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Song H, Hao Z, Feng H, Li R, Zhang R, Limesand SW, Zhao Y, Chen X. Insulin resistance and dyslipidemia in low-birth-weight goat kids. Front Vet Sci 2024; 11:1370640. [PMID: 38596462 PMCID: PMC11002208 DOI: 10.3389/fvets.2024.1370640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 03/06/2024] [Indexed: 04/11/2024] Open
Abstract
Low birth weight (LBW) impairs the development and health of livestock by affecting postnatal growth performance and metabolic health in adulthood. Previous studies on indigenous goats in southwest China showed that LBW goat kids had higher mortality and morbidity rates, including hepatic dyslipidemia and liver damage. However, the mechanism of insulin resistance affecting lipid metabolism under LBW conditions remains unclear. In this study, we conducted in vivo glucose-insulin metabolic studies, measured biochemical parameters, and analyzed related regulatory pathways. Both glucose tolerance tests and insulin tolerance tests indicated insulin resistance in LBW goat kids compared to controls (p < 0.05). The marker of insulin resistance, homeostasis model assessment (HOMA), was 2.85-fold higher in LBW than in control goats (p < 0.01). Additionally, elevated levels of free fatty acids in both plasma and skeletal muscle were observed in LBW goats compared to normal birth weight (NBW) goats (p < 0.05). Transcriptome analysis revealed impairments in lipid metabolism and insulin signaling in LBW goats. The observed lipid accumulation was associated with the upregulation of genes linked to fatty acid uptake and transport (FABP3), fatty acid oxidation (PPARA), triacylglycerol synthesis (LPIN1 and DGAT1), oxidative stress (ANKRD2), and insulin resistance (PGC1α). Furthermore, the insulin receptor substrate 2 (IRS2) was lower in the liver of LBW goat kids (p < 0.05). While there was no change in insulin function in skeletal muscle, LBW may lead to lipid accumulation in skeletal muscle by interfering with insulin function in the liver. These findings collectively impact the health and growth performance of livestock.
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Affiliation(s)
- Huihui Song
- College of Animal Science and Technology, Southwest University, Chongqing Key Laboratory of Herbivore Science, Chongqing, China
| | - Zhuohang Hao
- College of Animal Science and Technology, Southwest University, Chongqing Key Laboratory of Herbivore Science, Chongqing, China
| | - Hehan Feng
- College of Animal Science and Technology, Southwest University, Chongqing Key Laboratory of Herbivore Science, Chongqing, China
| | - Rui Li
- College of Animal Science and Technology, Southwest University, Chongqing Key Laboratory of Herbivore Science, Chongqing, China
| | - Ran Zhang
- Yunnan Center for Animal Disease Control and Prevention, Kunming, Yunnan, China
| | - Sean W. Limesand
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, AZ, United States
| | - Yongju Zhao
- College of Animal Science and Technology, Southwest University, Chongqing Key Laboratory of Herbivore Science, Chongqing, China
| | - Xiaochuan Chen
- College of Animal Science and Technology, Southwest University, Chongqing Key Laboratory of Herbivore Science, Chongqing, China
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Luna-Ramirez RI, Kelly AC, Anderson MJ, Bidwell CA, Goyal R, Limesand SW. Elevated Norepinephrine Stimulates Adipocyte Hyperplasia in Ovine Fetuses With Placental Insufficiency and IUGR. Endocrinology 2023; 165:bqad177. [PMID: 38035825 PMCID: PMC10726312 DOI: 10.1210/endocr/bqad177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 11/01/2023] [Accepted: 11/22/2023] [Indexed: 12/02/2023]
Abstract
Prevailing hypoxemia and hypoglycemia in near-term fetuses with placental insufficiency-induced intrauterine growth restriction (IUGR) chronically increases norepinephrine concentrations, which lower adrenergic sensitivity and lipid mobilization postnatally, indicating a predisposition for adiposity. To determine adrenergic-induced responses, we examined the perirenal adipose tissue transcriptome from IUGR fetuses with or without hypercatecholaminemia. IUGR was induced in sheep with maternal hyperthermia, and hypercatecholaminemia in IUGR was prevented with bilateral adrenal demedullation. Adipose tissue was collected from sham-operated control (CON) and IUGR fetuses and adrenal-demedullated control (CAD) and IUGR (IAD) fetuses. Norepinephrine concentrations were lower in IAD fetuses than in IUGR fetuses despite both being hypoxemic and hypoglycemic. In IUGR fetuses, perirenal adipose tissue mass relative to body mass was greater compared with the CON, adrenal-demedullated control, and IAD groups. Transcriptomic analysis identified 581 differentially expressed genes (DEGs) in CON vs IUGR adipose tissue and 193 DEGs in IUGR vs IAD adipose tissue. Integrated functional analysis of these 2 comparisons showed enrichment for proliferator-activated receptor signaling and metabolic pathways and identified adrenergic responsive genes. Within the adrenergic-regulated DEGs, we identified transcripts that regulate adipocyte proliferation and differentiation: adipogenesis regulatory factor, C/CCAAT/enhancer binding protein α, and sterol carrier protein 2. DEGs associated with the metabolic pathway included pyruvate dehydrogenase kinase 4, 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 4, IGF-binding proteins (IGFBP-5 and IGFBP-7). Sex-specific expression differences were also found for adipogenesis regulatory factor, pyruvate dehydrogenase kinase 4, IGFBP5, and IGFBP7. These findings indicate that sustained adrenergic stimulation during IUGR leads to adipocyte hyperplasia with alterations in metabolism, proliferation, and preadipocyte differentiation pathways.
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Affiliation(s)
- Rosa I Luna-Ramirez
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85719, USA
| | - Amy C Kelly
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85719, USA
| | - Miranda J Anderson
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85719, USA
| | | | - Ravi Goyal
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85719, USA
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85719, USA
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3
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Zhao W, Kelly AC, Luna-Ramirez RI, Bidwell CA, Anderson MJ, Limesand SW. Decreased Pyruvate but Not Fatty Acid Driven Mitochondrial Respiration in Skeletal Muscle of Growth Restricted Fetal Sheep. Int J Mol Sci 2023; 24:15760. [PMID: 37958743 PMCID: PMC10648961 DOI: 10.3390/ijms242115760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 10/26/2023] [Accepted: 10/28/2023] [Indexed: 11/15/2023] Open
Abstract
Fetuses with intrauterine growth restriction (FGR) have impaired oxidative and energy metabolism, with persistent consequences on their postnatal development. In this study, we test the hypothesis that FGR skeletal muscle has lower mitochondrial respiration rate and alters the transcriptomic profiles associated with energy metabolism in an ovine model. At late gestation, mitochondrial oxygen consumption rates (OCRs) and transcriptome profiles were evaluated in the skeletal muscle collected from FGR and control fetuses. The ex vivo mitochondrial OCRs were reduced (p < 0.01) in permeabilized FGR soleus muscle compared to the control muscle but only with pyruvate as the metabolic substrate. Mitochondrial OCRs were similar between the FGR and control groups for palmitoyl-carnitine (fatty acid-driven) or pyruvate plus palmitoyl-carnitine metabolic substrates. A total of 2284 genes were differentially expressed in the semitendinosus muscle from growth restricted fetuses (false discovery rate (FDR) ≤ 0.05). A pathway analysis showed that the upregulated genes (FGR compared to control) were overrepresented for autophagy, HIF-1, AMPK, and FOXO signaling pathways (all with an FDR < 0.05). In addition, the expression of genes modulating pyruvate's entry into the TCA cycle was downregulated, whereas the genes encoding key fatty acid oxidation enzymes were upregulated in the FGR muscle. These findings show that FGR skeletal muscle had attenuated mitochondrial pyruvate oxidation, possibly associated with the inability of pyruvate to enter into the TCA cycle, and that fatty acid oxidation might compensate for the attenuated energy metabolism. The current study provided phenotypic and molecular evidence for adaptive deficiencies in FGR skeletal muscle.
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Affiliation(s)
- Weicheng Zhao
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85719, USA; (W.Z.); (A.C.K.); (R.I.L.-R.); (M.J.A.)
| | - Amy C. Kelly
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85719, USA; (W.Z.); (A.C.K.); (R.I.L.-R.); (M.J.A.)
| | - Rosa I. Luna-Ramirez
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85719, USA; (W.Z.); (A.C.K.); (R.I.L.-R.); (M.J.A.)
| | | | - Miranda J. Anderson
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85719, USA; (W.Z.); (A.C.K.); (R.I.L.-R.); (M.J.A.)
| | - Sean W. Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85719, USA; (W.Z.); (A.C.K.); (R.I.L.-R.); (M.J.A.)
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Luna-Ramirez RI, Limesand SW, Goyal R, Pendleton AL, Rincón G, Zeng X, Luna-Nevárez G, Reyna-Granados JR, Luna-Nevárez P. Blood Transcriptomic Analyses Reveal Functional Pathways Associated with Thermotolerance in Pregnant Ewes Exposed to Environmental Heat Stress. Genes (Basel) 2023; 14:1590. [PMID: 37628641 PMCID: PMC10454332 DOI: 10.3390/genes14081590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/25/2023] [Accepted: 08/03/2023] [Indexed: 08/27/2023] Open
Abstract
Environmental heat stress triggers a series of compensatory mechanisms in sheep that are dependent on their genetic regulation of thermotolerance. Our objective was to identify genes and regulatory pathways associated with thermotolerance in ewes exposed to heat stress. We performed next-generation RNA sequencing on blood collected from 16 pregnant ewes, which were grouped as tolerant and non-tolerant to heat stress according to a physiological indicator. Additional samples were collected to measure complete blood count. A total of 358 differentially expressed genes were identified after applying selection criteria. Gene expression analysis detected 46 GO terms and 52 KEGG functional pathways. The top-three signaling pathways were p53, RIG-I-like receptor and FoxO, which suggested gene participation in biological processes such as apoptosis, cell signaling and immune response to external stressors. Network analysis revealed ATM, ISG15, IRF7, MDM4, DHX58 and TGFβR1 as over-expressed genes with high regulatory potential. A co-expression network involving the immune-related genes ISG15, IRF7 and DXH58 was detected in lymphocytes and monocytes, which was consistent with hematological findings. In conclusion, transcriptomic analysis revealed a non-viral immune mechanism involving apoptosis, which is induced by external stressors and appears to play an important role in the molecular regulation of heat stress tolerance in ewes.
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Affiliation(s)
- Rosa I. Luna-Ramirez
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Sean W. Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Ravi Goyal
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Alexander L. Pendleton
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85721, USA
| | | | - Xi Zeng
- Zoetis Inc., VMRD Genetics R&D, Kalamazoo, MI 49007, USA
| | - Guillermo Luna-Nevárez
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, Ciudad Obregón 85000, Mexico
| | - Javier R. Reyna-Granados
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, Ciudad Obregón 85000, Mexico
| | - Pablo Luna-Nevárez
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, Ciudad Obregón 85000, Mexico
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5
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Blomberg J, Luna Ramirez RI, Goyal D, Limesand SW, Goyal R. Sexual dimorphic gene expression profile of perirenal adipose tissue in ovine fetuses with growth restriction. Front Physiol 2023; 14:1179288. [PMID: 37601643 PMCID: PMC10437077 DOI: 10.3389/fphys.2023.1179288] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 07/06/2023] [Indexed: 08/22/2023] Open
Abstract
Worldwide, fetal growth restriction (FGR) affects 7%-10% of pregnancies, or roughly 20.5 million infants, each year. FGR increases not only neonatal mortality and morbidity but also the risk of obesity in later life. Currently, the molecular mechanisms by which FGR "programs" an obese phenotype are not well understood. Studies demonstrate that FGR females are more prone to obesity compared to males; however, the molecular mechanisms that lead to the sexually dimorphic programming of FGR are not known. Thus, we hypothesized that FGR leads to the sexually dimorphic programming of preadipocytes and reduces their ability to differentiate into mature adipocytes. To test the hypothesis, we utilized a maternal hyperthermia-induced placental insufficiency to restrict fetal growth in sheep. We collected perirenal adipose tissue from near-term (∼140 days gestation) male and female FGR and normal-weight fetal lambs (N = 4 to 5 in each group), examined the preadipocytes' differentiation potential, and identified differential mRNA transcript expression in perirenal adipose tissue. Male FGR fetuses have a lower cellular density (nuclei number/unit area) compared to control male fetuses. However, no difference was observed in female FGR fetuses compared to control female fetuses. In addition, the ability of preadipocytes to differentiate into mature adipocytes with fat accumulation was impaired in male FGR fetuses, but this was not observed in female FGR fetuses. Finally, we examined the genes and pathways involved in the sexually dimorphic programming of obesity by FGR. On enrichment of differentially expressed genes in males compared to females, the Thermogenesis KEGG Pathway was downregulated, and the Metabolic and Steroid Biosynthesis KEGG pathways were upregulated. On enrichment of differentially expressed genes in male FGR compared to male control, the Steroid Biosynthesis KEGG Pathway was downregulated, and the PPAR Signaling KEGG pathway was upregulated. No pathways were altered in females in response to growth restriction in perirenal adipose tissue. Thus, the present study demonstrates a sexually dimorphic program in response to growth restriction in sheep fetal perirenal adipose tissue.
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Affiliation(s)
| | | | | | | | - Ravi Goyal
- School of Animal and Comparative Biomedical Sciences, College of Agriculture and Life Sciences, University of Arizona, Tucson, AZ, United States
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Pendleton AL, Limesand SW, Goyal R. In Vivo Real-Time Study of Drug Effects on Carotid Blood Flow in the Ovine Fetus. J Vis Exp 2023. [PMID: 37184262 DOI: 10.3791/64551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023] Open
Abstract
The ability of an organism to maintain a constant blood flow to the brain in response to sudden surges in systemic blood pressure (BP) is known as cerebral autoregulation (CAR), which occurs in the carotid artery. In contrast to full-term neonates, preterm neonates are unable to reduce the cerebral blood flow (CBF) in response to increased systemic BP. In preterm neonates, this exposes the fragile cerebral vessels to high perfusion pressures, leading to their rupture and brain damage. Ex vivo studies using wire myography have demonstrated that carotid arteries from near-term fetuses constrict in response to the activation of adrenergic alpha1 receptors. This response is blunted in the preterm fetus. Thus, to examine the role of alpha1-AR in vivo, presented here is an innovative approach to determine the effects of drugs on a carotid arterial segment in vivo in an ovine fetus during the developmental progression of gestation. The presented data demonstrate the simultaneous measurement of fetal blood flow and blood pressure. The perivascular delivery system can be used to conduct a long-term study over several days. Additional applications for this method could include viral delivery systems to alter the expression of genes in a segment of the carotid artery. These methods could be applied to other blood vessels in the growing organism in utero as well as in adult organisms.
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Affiliation(s)
- Alexander L Pendleton
- School of Animal and Comparative Biomedical Sciences, College of Agriculture and Life Sciences, University of Arizona, Tucson
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, College of Agriculture and Life Sciences, University of Arizona, Tucson
| | - Ravi Goyal
- School of Animal and Comparative Biomedical Sciences, College of Agriculture and Life Sciences, University of Arizona, Tucson;
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7
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Goyal D, Limesand SW, Goyal R. Vascular Stem Cells and the Role of B-Raf Kinase in Survival, Proliferation, and Apoptosis. Int J Mol Sci 2023; 24:7483. [PMID: 37108645 PMCID: PMC10138574 DOI: 10.3390/ijms24087483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/04/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023] Open
Abstract
Neovascularization is an essential process in organismal development and aging. With aging, from fetal to adult life, there is a significant reduction in neovascularization potential. However, the pathways which play a role in increased neovascularization potential during fetal life are unknown. Although several studies proposed the idea of vascular stem cells (VSCs), the identification and essential survival mechanism are still not clear. In the present study, we isolated fetal VSCs from the ovine carotid artery and identified the pathways involved in their survival. We tested the hypothesis that fetal vessels contain a population of VSCs, and that B-Raf kinase is required for their survival. We conducted viability, apoptotic, and cell cycle stage assays on fetal and adult carotid arteries and isolated cells. To determine molecular mechanisms, we conducted RNAseq, PCR, and western blot experiments to characterize them and identify pathways essential for their survival. Results: A stem cell-like population was isolated from fetal carotid arteries grown in serum-free media. The isolated fetal VSCs contained markers for endothelial, smooth muscle, and adventitial cells, and formed a de novo blood vessel ex vivo. A transcriptomic analysis that compared fetal and adult arteries identified pathway enrichment for several kinases, including B-Raf kinase in fetal arteries. Furthermore, we demonstrated that B-Raf- Signal Transducer and Activator of Transcription 3 (STAT3)-Bcl2 is critical for the survival of these cells. Fetal arteries, but not adult arteries, contain VSCs, and B-Raf-STAT3-Bcl2 plays an important role in their survival and proliferation.
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Affiliation(s)
| | | | - Ravi Goyal
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85719, USA
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Castillo-Salas CA, Luna-Nevárez G, Reyna-Granados JR, Luna-Ramirez RI, Limesand SW, Luna-Nevárez P. Molecular markers for thermo-tolerance are associated with reproductive and physiological traits in Pelibuey ewes raised in a semiarid environment. J Therm Biol 2023; 112:103475. [PMID: 36796920 DOI: 10.1016/j.jtherbio.2023.103475] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 12/18/2022] [Accepted: 12/27/2022] [Indexed: 01/11/2023]
Abstract
Pelibuey sheep exhibit reproductive activity through the year, but warm weather lowers their fertility and demonstrates physiological limitations of environmental heat stress. Single nucleotide polymorphisms (SNPs) associated with heat stress tolerance in sheep have been reported previously. The objective was to validate the association of seven thermo-tolerance SNP markers with reproductive and physiological traits in Pelibuey ewes raised in a semiarid region. Pelibuey ewes were assigned to a cool (January 1st.- March 31st.; n = 101) or warm (April 1st.- August 31st.; n = 104) experimental group. All ewes were exposed to fertile rams and assessed for pregnancy diagnosis 90 days later; lambing day was reported at birth. These data served to calculate the reproductive traits of services per conception, prolificacy, days to estrus, days to conception, conception rate and lambing rate. Rectal temperature, rump/leg skin temperature and respiratory rate were measured and reported as physiological traits. Blood samples were collected and processed to extract DNA, which was genotyped using the TaqMan allelic discrimination method and qPCR. A mixed effects statistical model was used to validate associations between SNP genotypes and phenotypic traits. The SNPs rs421873172, rs417581105 and rs407804467 were confirmed as markers associated with reproductive and physiological traits (P < 0.05), and these SNPs were in the genes PAM, STAT1 and FBXO11, respectively. Interestingly, these SNP markers resulted as predictors for the evaluated traits but only in ewes from the warm group, which indicated their association with heat-stress tolerance. An additive SNP effect was confirmed with the highest contribution (P < 0.01) of the SNP rs417581105 for the evaluated traits. Reproductive performance improved (P < 0.05) and physiological parameters decreased in ewes carrying favorable SNP genotypes. In conclusion, three thermo-tolerance SNP markers were associated with improved reproductive and physiological traits in a prospective population of heat-stressed ewes raised in a semiarid environment.
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Affiliation(s)
- Candelario A Castillo-Salas
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, Ciudad Obregón, Sonora, 85000, México
| | - Guillermo Luna-Nevárez
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, Ciudad Obregón, Sonora, 85000, México
| | - Javier R Reyna-Granados
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, Ciudad Obregón, Sonora, 85000, México
| | - Rosa I Luna-Ramirez
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona, 85721, USA
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona, 85721, USA
| | - Pablo Luna-Nevárez
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, Ciudad Obregón, Sonora, 85000, México.
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Posont RJ, Most MS, Cadaret CN, Marks-Nelson ES, Beede KA, Limesand SW, Schmidt TB, Petersen JL, Yates DT. Primary myoblasts from intrauterine growth-restricted fetal sheep exhibit intrinsic dysfunction of proliferation and differentiation that coincides with enrichment of inflammatory cytokine signaling pathways. J Anim Sci 2022; 100:6652330. [PMID: 35908792 PMCID: PMC9339287 DOI: 10.1093/jas/skac145] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 04/14/2022] [Indexed: 12/14/2022] Open
Abstract
Intrauterine growth restriction (IUGR) is linked to lifelong reductions in muscle mass due to intrinsic functional deficits in myoblasts, but the mechanisms underlying these deficits are not known. Our objective was to determine if the deficits were associated with changes in inflammatory and adrenergic regulation of IUGR myoblasts, as was previously observed in IUGR muscle. Primary myoblasts were isolated from IUGR fetal sheep produced by hyperthermia-induced placental insufficiency (PI-IUGR; n = 9) and their controls (n = 9) and from IUGR fetal sheep produced by maternofetal inflammation (MI-IUGR; n = 6) and their controls (n = 7). Proliferation rates were less (P < 0.05) for PI-IUGR myoblasts than their controls and were not affected by incubation with IL-6, TNF-α, norepinephrine, or insulin. IκB kinase inhibition reduced (P < 0.05) proliferation of control myoblasts modestly in basal media but substantially in TNF-α-added media and reduced (P < 0.05) PI-IUGR myoblast proliferation substantially in basal and TNF-α-added media. Proliferation was greater (P < 0.05) for MI-IUGR myoblasts than their controls and was not affected by incubation with TNF-α. Insulin increased (P < 0.05) proliferation in both MI-IUGR and control myoblasts. After 72-h differentiation, fewer (P < 0.05) PI-IUGR myoblasts were myogenin+ than controls in basal and IL-6 added media but not TNF-α-added media. Fewer (P < 0.05) PI-IUGR myoblasts were desmin+ than controls in basal media only. Incubation with norepinephrine did not affect myogenin+ or desmin+ percentages, but insulin increased (P < 0.05) both markers in control and PI-IUGR myoblasts. After 96-h differentiation, fewer (P < 0.05) MI-IUGR myoblasts were myogenin+ and desmin+ than controls regardless of media, although TNF-α reduced (P < 0.05) desmin+ myoblasts for both groups. Differentiated PI-IUGR myoblasts had greater (P < 0.05) TNFR1, ULK2, and TNF-α-stimulated TLR4 gene expression, and PI-IUGR semitendinosus muscle had greater (P < 0.05) TNFR1 and IL6 gene expression, greater (P < 0.05) c-Fos protein, and less (P < 0.05) IκBα protein. Differentiated MI-IUGR myoblasts had greater (P < 0.05) TNFR1 and IL6R gene expression, tended to have greater (P = 0.07) ULK2 gene expression, and had greater (P < 0.05) β-catenin protein and TNF-α-stimulated phosphorylation of NFκB. We conclude that these enriched components of TNF-α/TNFR1/NFκB and other inflammatory pathways in IUGR myoblasts contribute to their dysfunction and help explain impaired muscle growth in the IUGR fetus.
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Affiliation(s)
- Robert J Posont
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Micah S Most
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Caitlin N Cadaret
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Eileen S Marks-Nelson
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Kristin A Beede
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, AZ 65721, USA
| | - Ty B Schmidt
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Jessica L Petersen
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Dustin T Yates
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
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10
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Camacho LE, Davis MA, Kelly AC, Steffens NR, Anderson MJ, Limesand SW. Prenatal Oxygen and Glucose Therapy Normalizes Insulin Secretion and Action in Growth Restricted Fetal Sheep. Endocrinology 2022; 163:6585511. [PMID: 35560217 PMCID: PMC9113332 DOI: 10.1210/endocr/bqac053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Indexed: 11/19/2022]
Abstract
Placental insufficiency (PI) lowers fetal oxygen and glucose concentrations, which disrupts glucose-insulin homeostasis and promotes fetal growth restriction (FGR). To date, prenatal treatments for FGR have not attempted to correct the oxygen and glucose supply simultaneously. Therefore, we investigated whether a five-day correction of oxygen and glucose concentrations in PI-FGR fetuses would normalize insulin secretion and glucose metabolism. Experiments were performed in near-term FGR fetal sheep with maternal hyperthermia-induced PI. Fetal arterial oxygen tension was increased to normal levels by increasing the maternal inspired oxygen fraction and glucose was infused into FGR fetuses (FGR-OG). FGR-OG fetuses were compared to maternal air insufflated, saline-infused fetuses (FGR-AS) and control fetuses. Prior to treatment, FGR fetuses were hypoxemic and hypoglycemic and had reduced glucose-stimulated insulin secretion (GSIS). During treatment, oxygen, glucose, and insulin concentrations increased, and norepinephrine concentrations decreased in FGR-OG fetuses, whereas FGR-AS fetuses were unaffected. On treatment day 4, glucose fluxes were measured with euglycemic and hyperinsulinemic-euglycemic clamps. During both clamps, rates of glucose utilization and production were greater in FGR-AS than FGR-OG fetuses, while glucose fluxes in FGR-OG fetuses were not different than control rates. After five-days of treatment, GSIS increased in FGR-OG fetuses to control levels and their ex vivo islet GSIS was greater than FGR-AS islets. Despite normalization in fetal characteristics, GSIS, and glucose fluxes, FGR-OG and FGR-AS fetuses weighed less than controls. These findings show that sustained, simultaneous correction of oxygen and glucose normalized GSIS and whole-body glucose fluxes in PI-FGR fetuses after the onset of FGR.
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Affiliation(s)
- Leticia E Camacho
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona 85719, USA
| | - Melissa A Davis
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona 85719, USA
| | - Amy C Kelly
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona 85719, USA
| | - Nathan R Steffens
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona 85719, USA
| | - Miranda J Anderson
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona 85719, USA
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona 85719, USA
- Correspondence: Sean W. Limesand, PhD, Animal and Comparative Biomedical Sciences, The University of Arizona, 1650 E Limberlost Dr, Tucson AZ 85719, USA.
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11
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Jones AK, Wang D, Goldstrohm DA, Brown LD, Rozance PJ, Limesand SW, Wesolowski SR. Tissue-specific responses that constrain glucose oxidation and increase lactate production with the severity of hypoxemia in fetal sheep. Am J Physiol Endocrinol Metab 2022; 322:E181-E196. [PMID: 34957858 PMCID: PMC8816623 DOI: 10.1152/ajpendo.00382.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Fetal hypoxemia decreases insulin and increases cortisol and norepinephrine concentrations and may restrict growth by decreasing glucose utilization and altering substrate oxidation. Specifically, we hypothesized that hypoxemia would decrease fetal glucose oxidation and increase lactate and pyruvate production. We tested this by measuring whole body glucose oxidation and lactate production, and molecular pathways in liver, muscle, adipose, and pancreas tissues of fetuses exposed to maternal hypoxemia for 9 days (HOX) compared with control fetal sheep (CON) in late gestation. Fetuses with more severe hypoxemia had lower whole body glucose oxidation rates, and HOX fetuses had increased lactate production from glucose. In muscle and adipose tissue, expression of the glucose transporter GLUT4 was decreased. In muscle, pyruvate kinase (PKM) and lactate dehydrogenase B (LDHB) expression was decreased. In adipose tissue, LDHA and lactate transporter (MCT1) expression was increased. In liver, there was decreased gene expression of PKLR and MPC2 and phosphorylation of PDH, and increased LDHA gene and LDH protein abundance. LDH activity, however, was decreased only in HOX skeletal muscle. There were no differences in basal insulin signaling across tissues, nor differences in pancreatic tissue insulin content, β-cell area, or genes regulating β-cell function. Collectively, these results demonstrate coordinated metabolic responses across tissues in the hypoxemic fetus that limit glucose oxidation and increase lactate and pyruvate production. These responses may be mediated by hypoxemia-induced endocrine responses including increased norepinephrine and cortisol, which inhibit pancreatic insulin secretion resulting in lower insulin concentrations and decreased stimulation of glucose utilization.NEW & NOTEWORTHY Hypoxemia lowered fetal glucose oxidation rates, based on severity of hypoxemia, and increased lactate production. This was supported by tissue-specific metabolic responses that may result from increased norepinephrine and cortisol concentrations, which decrease pancreatic insulin secretion and insulin concentrations and decrease glucose utilization. This highlights the vulnerability of metabolic pathways in the fetus and demonstrates that constrained glucose oxidation may represent an early event in response to sustained hypoxemia and fetal growth restriction.
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Affiliation(s)
- Amanda K Jones
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Dong Wang
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - David A Goldstrohm
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Laura D Brown
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Paul J Rozance
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
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12
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Limesand SW, Goyal R. Epigenetic Modifications Guide Maturational Processes in Rat Pancreatic Islets. Endocrinology 2022; 163:6446226. [PMID: 34849676 DOI: 10.1210/endocr/bqab243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Indexed: 11/19/2022]
Affiliation(s)
- Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona 85719, USA
| | - Ravi Goyal
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona 85719, USA
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13
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Luna-Nevárez G, Pendleton AL, Luna-Ramirez RI, Limesand SW, Reyna-Granados JR, Luna-Nevárez P. Genome-wide association study of a thermo-tolerance indicator in pregnant ewes exposed to an artificial heat-stressed environment. J Therm Biol 2021; 101:103095. [PMID: 34879913 DOI: 10.1016/j.jtherbio.2021.103095] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 09/07/2021] [Accepted: 09/14/2021] [Indexed: 11/26/2022]
Abstract
Environmental heat stress negatively influences sheep production in warm semi-arid regions. An animal's ability to tolerate warm weather is difficult to measure naturally due to environmental variability and genetic variation between animals. In this study we developed a thermo-tolerance indicator (TTI) to define heat stress tolerance in pregnant sheep in a controlled environment. Next, we performed a genome-wide association study (GWAS) to identify genomic regions and target genes associated with thermo-tolerance in sheep. Pregnant Columbia-Rambouillet crossbred ewes (n = 127) were heat-stressed inside a climate-controlled chamber for 57 days by increasing the temperature-humidity index to ≥30. Rectal temperature (RT) and feed intake (FI) data were collected daily and used for the predictive TTI analysis. After the tenth day of heat stress, the regression analyses revealed that FI was stable; however, when the ewe's RT exceeded 39.8 °C their FI was less than thermo-tolerant ewes. This average predicted temperature was used to classify each ewe as heat stress tolerant (≤39.8 °C) and non-heat stress tolerant (>39.8 °C). A GWAS analysis was performed and genomic regions were compared between heat stress tolerant and non-tolerant ewes. The single-marker genomic analysis detected 16 single nucleotide polymorphisms (SNP) associated with heat stress tolerance (P < 0.0001), whereas the multi-marker Bayesian analysis identified 8 overlapped 1-Mb chromosomal regions accounting for 11.39% of the genetic variation associated with tolerance to heat stress. Four intragenic SNP showed a remarkable contribution to thermo-tolerance, and these markers were within the genes FBXO11 (rs407804467), PHC3 (rs414179061), TSHR (rs418575898) and STAT1 (rs417581105). In conclusion, genomic regions harboring four intragenic SNP were associated with heat stress tolerance, and these candidate genes are proposed to influence heat tolerance in pregnant ewes subjected to an artificially induced warm climate. Moreover, these genetic markers could be suitable for use in further genetic selection programs in sheep managed in semi-arid regions.
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Affiliation(s)
- Guillermo Luna-Nevárez
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, Ciudad Obregón, Sonora, 85000, México
| | - Alexander L Pendleton
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona, 85721, USA
| | - Rosa I Luna-Ramirez
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona, 85721, USA
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona, 85721, USA
| | - Javier R Reyna-Granados
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, Ciudad Obregón, Sonora, 85000, México
| | - Pablo Luna-Nevárez
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, Ciudad Obregón, Sonora, 85000, México.
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14
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Jones AK, Rozance PJ, Brown LD, Lorca RA, Julian CG, Moore LG, Limesand SW, Wesolowski SR. Uteroplacental nutrient flux and evidence for metabolic reprogramming during sustained hypoxemia. Physiol Rep 2021; 9:e15033. [PMID: 34558219 PMCID: PMC8461030 DOI: 10.14814/phy2.15033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 08/23/2021] [Indexed: 01/14/2023] Open
Abstract
Gestational hypoxemia is often associated with reduced birth weight, yet how hypoxemia controls uteroplacental nutrient metabolism and supply to the fetus is unclear. This study tested the effects of maternal hypoxemia (HOX) between 0.8 and 0.9 gestation on uteroplacental nutrient metabolism and flux to the fetus in pregnant sheep. Despite hypoxemia, uteroplacental and fetal oxygen utilization and net glucose and lactate uptake rates were similar in HOX (n = 11) compared to CON (n = 7) groups. HOX fetuses had increased lactate and pyruvate concentrations and increased net pyruvate output to the utero-placenta. In the HOX group, uteroplacental flux of alanine to the fetus was decreased, as was glutamate flux from the fetus. HOX fetuses had increased alanine and decreased aspartate, serine, and glutamate concentrations. In HOX placental tissue, we identified hypoxic responses that should increase mitochondrial efficiency (decreased SDHB, increased COX4I2) and increase lactate production from pyruvate (increased LDHA protein and LDH activity, decreased LDHB and MPC2), both resembling metabolic reprogramming, but with evidence for decreased (PFK1, PKM2), rather than increased, glycolysis and AMPK phosphorylation. This supports a fetal-uteroplacental shuttle during sustained hypoxemia whereby uteroplacental tissues produce lactate as fuel for the fetus using pyruvate released from the fetus, rather than pyruvate produced from glucose in the placenta, given the absence of increased uteroplacental glucose uptake and glycolytic gene activation. Together, these results provide new mechanisms for how hypoxemia, independent of AMPK activation, regulates uteroplacental metabolism and nutrient allocation to the fetus, which allow the fetus to defend its oxidative metabolism and growth.
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Affiliation(s)
- Amanda K. Jones
- Perinatal Research Center, Department of PediatricsUniversity of Colorado School of MedicineAuroraColoradoUSA
| | - Paul J. Rozance
- Perinatal Research Center, Department of PediatricsUniversity of Colorado School of MedicineAuroraColoradoUSA
| | - Laura D. Brown
- Perinatal Research Center, Department of PediatricsUniversity of Colorado School of MedicineAuroraColoradoUSA
| | - Ramón A. Lorca
- Department of Obstetrics and GynecologyUniversity of Colorado School of MedicineAuroraColoradoUSA
| | - Colleen G. Julian
- Department of MedicineUniversity of Colorado School of MedicineAuroraColoradoUSA
| | - Lorna G. Moore
- Department of Obstetrics and GynecologyUniversity of Colorado School of MedicineAuroraColoradoUSA
| | - Sean W. Limesand
- School of Animal and Comparative Biomedical SciencesUniversity of ArizonaTucsonArizonaUSA
| | - Stephanie R. Wesolowski
- Perinatal Research Center, Department of PediatricsUniversity of Colorado School of MedicineAuroraColoradoUSA
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15
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Pendleton AL, Wesolowski SR, Regnault TRH, Lynch RM, Limesand SW. Dimming the Powerhouse: Mitochondrial Dysfunction in the Liver and Skeletal Muscle of Intrauterine Growth Restricted Fetuses. Front Endocrinol (Lausanne) 2021; 12:612888. [PMID: 34079518 PMCID: PMC8165279 DOI: 10.3389/fendo.2021.612888] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 04/22/2021] [Indexed: 11/14/2022] Open
Abstract
Intrauterine growth restriction (IUGR) of the fetus, resulting from placental insufficiency (PI), is characterized by low fetal oxygen and nutrient concentrations that stunt growth rates of metabolic organs. Numerous animal models of IUGR recapitulate pathophysiological conditions found in human fetuses with IUGR. These models provide insight into metabolic dysfunction in skeletal muscle and liver. For example, cellular energy production and metabolic rate are decreased in the skeletal muscle and liver of IUGR fetuses. These metabolic adaptations demonstrate that fundamental processes in mitochondria, such as substrate utilization and oxidative phosphorylation, are tempered in response to low oxygen and nutrient availability. As a central metabolic organelle, mitochondria coordinate cellular metabolism by coupling oxygen consumption to substrate utilization in concert with tissue energy demand and accretion. In IUGR fetuses, reducing mitochondrial metabolic capacity in response to nutrient restriction is advantageous to ensure fetal survival. If permanent, however, these adaptations may predispose IUGR fetuses toward metabolic diseases throughout life. Furthermore, these mitochondrial defects may underscore developmental programming that results in the sequela of metabolic pathologies. In this review, we examine how reduced nutrient availability in IUGR fetuses impacts skeletal muscle and liver substrate catabolism, and discuss how enzymatic processes governing mitochondrial function, such as the tricarboxylic acid cycle and electron transport chain, are regulated. Understanding how deficiencies in oxygen and substrate metabolism in response to placental restriction regulate skeletal muscle and liver metabolism is essential given the importance of these tissues in the development of later lifer metabolic dysfunction.
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Affiliation(s)
- Alexander L. Pendleton
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, AZ, United States
| | - Stephanie R. Wesolowski
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States
| | | | - Ronald M. Lynch
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, AZ, United States
| | - Sean W. Limesand
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, AZ, United States
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16
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Davis MA, Camacho LE, Pendleton AL, Antolic AT, Luna-Ramirez RI, Kelly AC, Steffens NR, Anderson MJ, Limesand SW. Augmented glucose production is not contingent on high catecholamines in fetal sheep with IUGR. J Endocrinol 2021; 249:195-207. [PMID: 33994373 PMCID: PMC8175032 DOI: 10.1530/joe-21-0071] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 04/22/2021] [Indexed: 01/04/2023]
Abstract
Fetuses with intrauterine growth restriction (IUGR) have high concentrations of catecholamines, which lowers the insulin secretion and glucose uptake. Here, we studied the effect of hypercatecholaminemia on glucose metabolism in sheep fetuses with placental insufficiency-induced IUGR. Norepinephrine concentrations are elevated throughout late gestation in IUGR fetuses but not in IUGR fetuses with a bilateral adrenal demedullation (IAD) at 0.65 of gestation. Euglycemic (EC) and hyperinsulinemic-euglycemic (HEC) clamps were performed in control, intact-IUGR, and IAD fetuses at 0.87 of gestation. Compared to controls, basal oxygen, glucose, and insulin concentrations were lower in IUGR groups. Norepinephrine concentrations were five-fold higher in IUGR fetuses than in IAD fetuses. During the EC, rates of glucose entry (GER, umbilical + exogenous), glucose utilization (GUR), and glucose oxidation (GOR) were greater in IUGR groups than in controls. In IUGR and IAD fetuses with euglycemia and euinsulinemia, glucose production rates (GPR) remained elevated. During the HEC, GER and GOR were not different among groups. In IUGR and IAD fetuses, GURs were 40% greater than in controls, which paralleled the sustained GPR despite hyperinsulinemia. Glucose-stimulated insulin concentrations were augmented in IAD fetuses compared to IUGR fetuses. Fetal weights were not different between IUGR groups but were less than controls. Regardless of norepinephrine concentrations, IUGR fetuses not only develop greater peripheral insulin sensitivity for glucose utilization but also develop hepatic insulin resistance because GPR was maintained and unaffected by euglycemia or hyperinsulinemia. These findings show that adaptation in glucose metabolism of IUGR fetuses are independent of catecholamines, which implicate that hypoxemia and hypoglycemia cause the metabolic responses.
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Affiliation(s)
- Melissa A Davis
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - Leticia E Camacho
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - Alexander L Pendleton
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - Andrew T Antolic
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - Rosa I Luna-Ramirez
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - Amy C Kelly
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - Nathan R Steffens
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - Miranda J Anderson
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
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17
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Luna-Nevarez G, Kelly AC, Camacho LE, Limesand SW, Reyna-Granados JR, Luna-Nevarez P. Discovery and validation of candidate SNP markers associated to heat stress response in pregnant ewes managed inside a climate-controlled chamber. Trop Anim Health Prod 2020; 52:3457-3466. [PMID: 32939704 DOI: 10.1007/s11250-020-02379-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 09/10/2020] [Indexed: 11/28/2022]
Abstract
Sheep production in desert environments during summer is challenging due to heat stress which reduces feed intake, growth, and fertility. Despite warm conditions, some ewes are able to maintain a normal performance suggesting the existence of genetic bases underlying heat tolerance. Our objective was to discover and validate genetic markers associated with thermo-tolerance in pregnant ewes exposed to warm environmental conditions. Using a well-defined model laboratory of heat stress in sheep, pregnant Columbia-Rambouillet crossbred ewes (n = 100) were examined. Following acclimation to the laboratory at thermo-neutral conditions, heat stress was induced in ewes by increasing the temperature-humidity index in a control environmental chamber during mid-gestation. Feed intake, water consumption, and rectal temperature were recorded daily and used to establish the heat stress tolerance index (HSTI) for each ewe. Rectal temperature was a predictor (P < 0.05) of feed intake, and the regression coefficient was used to classify the HSTI. In a subset of 24 ewes, a genome-wide association study (GWAS) was performed using the Illumina OvineSNP50 BeadChip. Single-marker analysis detected 3 intragenic SNPs associated with HSTI (P value = 10-5). Bayesian multi-marker approach discovered 26 chromosomal regions across the genome which accounted for 9.8% of the variation associated with HSTI. In an independent sheep population (n = 42), the three discovered SNPs were validated as molecular markers associated with thermo-tolerance phenotypic traits. These SNPs were located within the genes F13A1, PAM, and PRELID2. In conclusion, three SNPs appear to be novel molecular markers associated with heat stress tolerance in pregnant ewes providing new knowledge about genetic foundations of thermo-tolerance.
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Affiliation(s)
- Guillermo Luna-Nevarez
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, 85000, Ciudad Obregón, Sonora, México
| | - Amy C Kelly
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, 85721, USA
| | - Leticia E Camacho
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, 85721, USA
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, 85721, USA
| | - Javier R Reyna-Granados
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, 85000, Ciudad Obregón, Sonora, México
| | - Pablo Luna-Nevarez
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, 85000, Ciudad Obregón, Sonora, México.
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18
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Davis MA, Camacho LE, Anderson MJ, Steffens NR, Pendleton AL, Kelly AC, Limesand SW. Chronically elevated norepinephrine concentrations lower glucose uptake in fetal sheep. Am J Physiol Regul Integr Comp Physiol 2020; 319:R255-R263. [PMID: 32667834 PMCID: PMC7509250 DOI: 10.1152/ajpregu.00365.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 07/13/2020] [Accepted: 07/13/2020] [Indexed: 12/13/2022]
Abstract
Fetal conditions associated with placental insufficiency and intrauterine growth restriction (IUGR) chronically elevate plasma norepinephrine (NE) concentrations. Our objective was to evaluate the effects of chronically elevated NE on insulin-stimulated glucose metabolism in normally grown, non-IUGR fetal sheep, which are independent of other IUGR-related reductions in nutrients and oxygen availability. After surgical placement of catheters, near-term fetuses received either a saline (control) or NE intravenous infusion with controlled euglycemia. In NE fetuses, plasma NE concentrations were 5.5-fold greater than controls, and fetal euglycemia was maintained with a maternal insulin infusion. Insulin secretion was blunted in NE fetuses during an intravenous glucose tolerance test. Weight-specific fluxes for glucose were measured during a euinsulinemic-euglycemic clamp (EEC) and a hyperinsulinemic-euglycemic clamp (HEC). Plasma glucose and insulin concentrations were not different between groups within each clamp, but insulin concentrations increased 10-fold between the EEC and the HEC. During the EEC, rates of glucose uptake (umbilical uptake + exogenous infusion) and glucose utilization were 47% and 35% lower (P < 0.05) in NE fetuses compared with controls. During the HEC, rates of glucose uptake were 28% lower (P < 0.05) in NE fetuses than controls. Glucose production was undetectable in either group, and glucose oxidation was unaffected by the NE infusion. These findings indicate that chronic exposure to high plasma NE concentrations lowers rates of net glucose uptake in the fetus without affecting glucose oxidation rates or initiating endogenous glucose production. Lower fetal glucose uptake was independent of insulin, which indicates insulin resistance as a consequence of chronically elevated NE.
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Affiliation(s)
- Melissa A Davis
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
| | - Leticia E Camacho
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
| | - Miranda J Anderson
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
| | - Nathan R Steffens
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
| | - Alexander L Pendleton
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
| | - Amy C Kelly
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
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19
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Pendleton AL, Antolic AT, Kelly AC, Davis MA, Camacho LE, Doubleday K, Anderson MJ, Langlais PR, Lynch RM, Limesand SW. Lower oxygen consumption and Complex I activity in mitochondria isolated from skeletal muscle of fetal sheep with intrauterine growth restriction. Am J Physiol Endocrinol Metab 2020; 319:E67-E80. [PMID: 32396498 PMCID: PMC7468780 DOI: 10.1152/ajpendo.00057.2020] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/30/2020] [Accepted: 05/04/2020] [Indexed: 01/25/2023]
Abstract
Fetal sheep with placental insufficiency-induced intrauterine growth restriction (IUGR) have lower hindlimb oxygen consumption rates (OCRs), indicating depressed mitochondrial oxidative phosphorylation capacity in their skeletal muscle. We hypothesized that OCRs are lower in skeletal muscle mitochondria from IUGR fetuses, due to reduced electron transport chain (ETC) activity and lower abundances of tricarboxylic acid (TCA) cycle enzymes. IUGR sheep fetuses (n = 12) were created with mid-gestation maternal hyperthermia and compared with control fetuses (n = 12). At 132 ± 1 days of gestation, biceps femoris muscles were collected, and the mitochondria were isolated. Mitochondria from IUGR muscle have 47% lower State 3 (Complex I-dependent) OCRs than controls, whereas State 4 (proton leak) OCRs were not different between groups. Furthermore, Complex I, but not Complex II or IV, enzymatic activity was lower in IUGR fetuses compared with controls. Proteomic analysis (n = 6/group) identified 160 differentially expressed proteins between groups, with 107 upregulated and 53 downregulated mitochondria proteins in IUGR fetuses compared with controls. Although no differences were identified in ETC subunit protein abundances, abundances of key TCA cycle enzymes [isocitrate dehydrogenase (NAD+) 3 noncatalytic subunit β (IDH3B), succinate-CoA ligase ADP-forming subunit-β (SUCLA2), and oxoglutarate dehydrogenase (OGDH)] were lower in IUGR mitochondria. IUGR mitochondria had a greater abundance of a hypoxia-inducible protein, NADH dehydrogenase 1α subcomplex 4-like 2, which is known to incorporate into Complex I and lower Complex I-mediated NADH oxidation. Our findings show that mitochondria from IUGR skeletal muscle adapt to hypoxemia and hypoglycemia by lowering Complex I activity and TCA cycle enzyme concentrations, which together, act to lower OCR and NADH production/oxidation in IUGR skeletal muscle.
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Affiliation(s)
- Alexander L Pendleton
- Physiological Sciences Graduate Interdisciplinary Program, University of Arizona, Tucson, Arizona
| | - Andrew T Antolic
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
| | - Amy C Kelly
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
| | - Melissa A Davis
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
| | - Leticia E Camacho
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
| | - Kevin Doubleday
- Department of Epidemiology and Biostatistics, College of Public Health, University of Arizona, Tucson, Arizona
| | - Miranda J Anderson
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
| | - Paul R Langlais
- Physiological Sciences Graduate Interdisciplinary Program, University of Arizona, Tucson, Arizona
- Department of Medicine, University of Arizona, Tucson, Arizona
| | - Ronald M Lynch
- Physiological Sciences Graduate Interdisciplinary Program, University of Arizona, Tucson, Arizona
- Department of Physiology, University of Arizona, Tucson, Arizona
| | - Sean W Limesand
- Physiological Sciences Graduate Interdisciplinary Program, University of Arizona, Tucson, Arizona
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
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Yates DT, Camacho LE, Kelly AC, Steyn LV, Davis MA, Antolic AT, Anderson MJ, Goyal R, Allen RE, Papas KK, Hay WW, Limesand SW. Postnatal β2 adrenergic treatment improves insulin sensitivity in lambs with IUGR but not persistent defects in pancreatic islets or skeletal muscle. J Physiol 2019; 597:5835-5858. [PMID: 31665811 PMCID: PMC6911010 DOI: 10.1113/jp278726] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 10/28/2019] [Indexed: 12/21/2022] Open
Abstract
Key points Previous studies in fetuses with intrauterine growth restriction (IUGR) have shown that adrenergic dysregulation was associated with low insulin concentrations and greater insulin sensitivity. Although whole‐body glucose clearance is normal, 1‐month‐old lambs with IUGR at birth have higher rates of hindlimb glucose uptake, which may compensate for myocyte deficiencies in glucose oxidation. Impaired glucose‐stimulated insulin secretion in IUGR lambs is due to lower intra‐islet insulin availability and not from glucose sensing. We investigated adrenergic receptor (ADR) β2 desensitization by administering oral ADRβ modifiers for the first month after birth to activate ADRβ2 and antagonize ADRβ1/3. In IUGR lambs ADRβ2 activation increased whole‐body glucose utilization rates and insulin sensitivity but had no effect on isolated islet or myocyte deficiencies. IUGR establishes risk for developing diabetes. In IUGR lambs we identified disparities in key aspects of glucose‐stimulated insulin secretion and insulin‐stimulated glucose oxidation, providing new insights into potential mechanisms for this risk.
Abstract Placental insufficiency causes intrauterine growth restriction (IUGR) and disturbances in glucose homeostasis with associated β adrenergic receptor (ADRβ) desensitization. Our objectives were to measure insulin‐sensitive glucose metabolism in neonatal lambs with IUGR and to determine whether daily treatment with ADRβ2 agonist and ADRβ1/β3 antagonists for 1 month normalizes their glucose metabolism. Growth, glucose‐stimulated insulin secretion (GSIS) and glucose utilization rates (GURs) were measured in control lambs, IUGR lambs and IUGR lambs treated with adrenergic receptor modifiers: clenbuterol atenolol and SR59230A (IUGR‐AR). In IUGR lambs, islet insulin content and GSIS were less than in controls; however, insulin sensitivity and whole‐body GUR were not different from controls. Of importance, ADRβ2 stimulation with β1/β3 inhibition increases both insulin sensitivity and whole‐body glucose utilization in IUGR lambs. In IUGR and IUGR‐AR lambs, hindlimb GURs were greater but fractional glucose oxidation rates and ex vivo skeletal muscle glucose oxidation rates were lower than controls. Glucose transporter 4 (GLUT4) was lower in IUGR and IUGR‐AR skeletal muscle than in controls but GLUT1 was greater in IUGR‐AR. ADRβ2, insulin receptor, glycogen content and citrate synthase activity were similar among groups. In IUGR and IUGR‐AR lambs heart rates were greater, which was independent of cardiac ADRβ1 activation. We conclude that targeted ADRβ2 stimulation improved whole‐body insulin sensitivity but minimally affected defects in GSIS and skeletal muscle glucose oxidation. We show that risk factors for developing diabetes are independent of postnatal catch‐up growth in IUGR lambs as early as 1 month of age and are inherent to the islets and myocytes. Previous studies in fetuses with intrauterine growth restriction (IUGR) have shown that adrenergic dysregulation was associated with low insulin concentrations and greater insulin sensitivity. Although whole‐body glucose clearance is normal, 1‐month‐old lambs with IUGR at birth have higher rates of hindlimb glucose uptake, which may compensate for myocyte deficiencies in glucose oxidation. Impaired glucose‐stimulated insulin secretion in IUGR lambs is due to lower intra‐islet insulin availability and not from glucose sensing. We investigated adrenergic receptor (ADR) β2 desensitization by administering oral ADRβ modifiers for the first month after birth to activate ADRβ2 and antagonize ADRβ1/3. In IUGR lambs ADRβ2 activation increased whole‐body glucose utilization rates and insulin sensitivity but had no effect on isolated islet or myocyte deficiencies. IUGR establishes risk for developing diabetes. In IUGR lambs we identified disparities in key aspects of glucose‐stimulated insulin secretion and insulin‐stimulated glucose oxidation, providing new insights into potential mechanisms for this risk.
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Affiliation(s)
- Dustin T Yates
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Leticia E Camacho
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Amy C Kelly
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Leah V Steyn
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Melissa A Davis
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Andrew T Antolic
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Miranda J Anderson
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Ravi Goyal
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Ronald E Allen
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Klearchos K Papas
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - William W Hay
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
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Pendleton AL, Humphreys LR, Davis MA, Camacho LE, Anderson MJ, Limesand SW. Increased pyruvate dehydrogenase activity in skeletal muscle of growth-restricted ovine fetuses. Am J Physiol Regul Integr Comp Physiol 2019; 317:R513-R520. [PMID: 31314546 PMCID: PMC6842904 DOI: 10.1152/ajpregu.00106.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 07/16/2019] [Accepted: 07/16/2019] [Indexed: 12/13/2022]
Abstract
Fetal sheep with placental insufficiency-induced intrauterine growth restriction (IUGR) have lower fractional rates of glucose oxidation and greater gluconeogenesis, indicating lactate shuttling between skeletal muscle and liver. Suppression of pyruvate dehydrogenase (PDH) activity was proposed because of greater pyruvate dehydrogenase kinase (PDK) 4 and PDK1 mRNA concentrations in IUGR muscle. Although PDK1 and PDK4 inhibit PDH activity to reduce pyruvate metabolism, PDH protein concentrations and activity have not been examined in skeletal muscle from IUGR fetuses. Therefore, we evaluated the protein concentrations and activity of PDH and the kinases and phosphatases that regulate PDH phosphorylation status in the semitendinosus muscle from placenta insufficiency-induced IUGR sheep fetuses and control fetuses. Immunoblots were performed for PDH, phosphorylated PDH (E1α), PDK1, PDK4, and pyruvate dehydrogenase phosphatase 1 and 2 (PDP1 and PDP2, respectively). Additionally, the PDH, lactate dehydrogenase (LDH), and citrate synthase (CS) enzymatic activities were measured. Phosphorylated PDH concentrations were 28% lower (P < 0.01) and PDH activity was 67% greater (P < 0.01) in IUGR fetal muscle compared with control. PDK1, PDK4, PDP1, PDP2, and PDH concentrations were not different between groups. CS and LDH activities were also unaffected. Contrary to the previous speculation, PDH activity was greater in skeletal muscle from IUGR fetuses, which parallels lower phosphorylated PDH. Therefore, greater expression of PDK1 and PDK4 mRNA did not translate to greater PDK1 or PDK4 protein concentrations or inhibition of PDH as proposed. Instead, these findings show greater PDH activity in IUGR fetal muscle, which indicates that alternative regulatory mechanisms are responsible for lower pyruvate catabolism.
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Affiliation(s)
- Alexander L Pendleton
- Physiological Sciences Graduate Interdisciplinary Program, The University of Arizona, Tucson, Arizona
| | - Laurel R Humphreys
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona
| | - Melissa A Davis
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona
| | - Leticia E Camacho
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona
| | - Miranda J Anderson
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona
| | - Sean W Limesand
- Physiological Sciences Graduate Interdisciplinary Program, The University of Arizona, Tucson, Arizona
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona
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Limesand SW. Gestational Diabetes-Induced Programming of Pancreatic Islets. Endocrinology 2019; 160:2117-2118. [PMID: 31373637 DOI: 10.1210/en.2019-00537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 07/29/2019] [Indexed: 11/19/2022]
Affiliation(s)
- Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
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Jones AK, Rozance PJ, Brown LD, Goldstrohm DA, Hay WW, Limesand SW, Wesolowski SR. Sustained hypoxemia in late gestation potentiates hepatic gluconeogenic gene expression but does not activate glucose production in the ovine fetus. Am J Physiol Endocrinol Metab 2019; 317:E1-E10. [PMID: 30964701 PMCID: PMC6732654 DOI: 10.1152/ajpendo.00069.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 04/01/2019] [Accepted: 04/04/2019] [Indexed: 02/08/2023]
Abstract
Fetal hypoxemia is associated with pregnancy conditions that cause an early activation of fetal glucose production. However, the independent role of hypoxemia to activate this pathway is not well understood. We hypothesized that fetal hypoxemia would activate fetal glucose production by decreasing umbilical glucose uptake and increasing counter-regulatory hormone concentrations. We induced hypoxemia for 9 days with maternal tracheal N2 gas insufflation to reduce maternal and fetal arterial Po2 by ~20% (HOX) compared with fetuses from ewes receiving intratracheal compressed air (CON). At 0.9 of gestation, fetal metabolic studies were performed (n = 7 CON, 11 HOX). Umbilical blood flow rates, net fetal oxygen and glucose uptake rates, and fetal arterial plasma glucose concentrations were not different between the two groups. Fetal glucose utilization rates were lower in HOX versus CON fetuses but not different from umbilical glucose uptake rates, demonstrating the absence of endogenous glucose production. In liver tissue, mRNA expression of gluconeogenic genes G6PC (P < 0.01) and PCK1 (P = 0.06) were six- and threefold greater in HOX fetuses versus CON fetuses. Increased fetal norepinephrine and cortisol concentrations and hepatic G6PC and PCK1 expression were inversely related to fetal arterial Po2. These findings support a role for fetal hypoxemia to act with counter-regulatory hormones to potentiate fetal hepatic gluconeogenic gene expression. However, in the absence of decreased net fetal glucose uptake rates and plasma glucose concentrations, hypoxemia-induced gluconeogenic gene activation is not sufficient to activate fetal glucose production.
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Affiliation(s)
- Amanda K Jones
- Department of Pediatrics, University of Colorado School of Medicine , Aurora, Colorado
| | - Paul J Rozance
- Department of Pediatrics, University of Colorado School of Medicine , Aurora, Colorado
| | - Laura D Brown
- Department of Pediatrics, University of Colorado School of Medicine , Aurora, Colorado
| | - David A Goldstrohm
- Department of Pediatrics, University of Colorado School of Medicine , Aurora, Colorado
| | - William W Hay
- Department of Pediatrics, University of Colorado School of Medicine , Aurora, Colorado
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona , Tucson, Arizona
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Beede KA, Limesand SW, Petersen JL, Yates DT. Real supermodels wear wool: summarizing the impact of the pregnant sheep as an animal model for adaptive fetal programming. Anim Front 2019; 9:34-43. [PMID: 31608163 PMCID: PMC6777506 DOI: 10.1093/af/vfz018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Affiliation(s)
- Kristin A Beede
- Department of Animal Science, University of Nebraska - Lincoln, Lincoln, NE
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, AZ
| | - Jessica L Petersen
- Department of Animal Science, University of Nebraska - Lincoln, Lincoln, NE
| | - Dustin T Yates
- Department of Animal Science, University of Nebraska - Lincoln, Lincoln, NE
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Abstract
Maternal and paternal factors influence offspring development and program its genome for successful postnatal life. Based on the stressors during gestation, the pregnant female prepares the fetus for the outside environment. This preparation is achieved by changing the epigenome of the fetus and is referred to as 'developmental programming'. For instance, nutritional insufficiency in utero will lead to programming events that prepare the fetus to cope up with nutrient scarcity following birth; however, offspring may not face nutrient scarcity following birth. This discrepancy between predicted and exposed postnatal environments are perceived as 'stress' by the offspring and may result in cardiovascular and metabolic disorders. Thus, this developmental programming may be both beneficial as well as harmful depending on the prenatal vs postnatal environment. Over the past three decades, accumulating evidence supports the hypothesis of Developmental Origin of Health and Disease (DOHaD) by the programming of the fetal phenotype without altering the genotype per se. These heritable modifications in gene expression occur through DNA methylation, histone modification and noncoding RNA-associated gene activation or silencing, and all are defined as epigenetic modifications. In the present review, we will summarize the evidence supporting epigenetic regulation as a significant component in DOHaD.
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Affiliation(s)
- Dipali Goyal
- School of Animal and Comparative Biomedical Sciences, College of Agriculture and Life Sciences, University of Arizona, Tucson, Arizona, USA
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, College of Agriculture and Life Sciences, University of Arizona, Tucson, Arizona, USA
| | - Ravi Goyal
- School of Animal and Comparative Biomedical Sciences, College of Agriculture and Life Sciences, University of Arizona, Tucson, Arizona, USA
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Limesand SW, Thornburg KL, Harding JE. 30th anniversary for the Developmental Origins of Endocrinology. J Endocrinol 2019; 242:JOE-19-0227.R1. [PMID: 31125977 DOI: 10.1530/joe-19-0227] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 05/23/2019] [Indexed: 11/08/2022]
Abstract
This special issue for the Journal of Endocrinology celebrates the 30th anniversary of David Barker's seminal findings that led to the scientific field of the Developmental Origins of Health and Disease (DOHaD). In 1989, Barker and colleagues reported that low birth weight and weight at one year, proxies for fetal growth restriction, were related to an individual's risk for developing hypertension and cardiovascular heart disease. Barker's initial epidemiological studies also demonstrated that low birth weight was predictive of later glucose intolerance, Type 2 Diabetes, and other metabolic-related diseases. As the developmental origins concept developed, the number of epidemiological studies continued to expand globally, consistently demonstrating the higher risk of developing chronic degenerative diseases if one was born small. In this thematic issue on the early origins of disease, there are a series of review articles and research papers that capture the impact of early events on endocrine systems, as major mechanisms underlying Barker's original observations. Importantly, over the past 30 years as the DOHaD concept has become widely accepted, we have seen it applied to an ever expanding breadth of human health problems. This expansion is evidenced by the growth of new model systems and establishment of new causal relationships in neuroendocrinology, reproductive systems, obesity, and behavior. The importance the DOHaD concept, its continued evolution, and new underlying mechanism are captured in the articles of this issue dedicated to Professor Barker's legacy.
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Affiliation(s)
- Sean W Limesand
- S Limesand, Animal Sciences, University of Arizona, Tucson, 85719, United States
| | - Kent L Thornburg
- K Thornburg, Heart Research Center, Oregon Health and Science University, Portland, 97239, United States
| | - Jane E Harding
- J Harding, Medicine and Biology, Research Centre for Developmental, Auckland, New Zealand
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Kelly AC, Smith KE, Purvis WG, Min CG, Weber CS, Cooksey AM, Hasilo C, Paraskevas S, Suszynski TM, Weegman BP, Anderson MJ, Camacho LE, Harland RC, Loudovaris T, Jandova J, Molano DS, Price ND, Georgiev IG, Scott WE, Manas D, Shaw J, O’Gorman D, Kin T, McCarthy FM, Szot GL, Posselt AM, Stock PG, Karatzas T, Shapiro WJ, Lynch RM, Limesand SW, Papas KK. Oxygen Perfusion (Persufflation) of Human Pancreata Enhances Insulin Secretion and Attenuates Islet Proinflammatory Signaling. Transplantation 2019; 103:160-167. [PMID: 30095738 PMCID: PMC6371803 DOI: 10.1097/tp.0000000000002400] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND All human islets used in research and for the clinical treatment of diabetes are subject to ischemic damage during pancreas procurement, preservation, and islet isolation. A major factor influencing islet function is exposure of pancreata to cold ischemia during unavoidable windows of preservation by static cold storage (SCS). Improved preservation methods may prevent this functional deterioration. In the present study, we investigated whether pancreas preservation by gaseous oxygen perfusion (persufflation) better preserved islet function versus SCS. METHODS Human pancreata were preserved by SCS or by persufflation in combination with SCS. Islets were subsequently isolated, and preparations in each group matched for SCS or total preservation time were compared using dynamic glucose-stimulated insulin secretion as a measure of β-cell function and RNA sequencing to elucidate transcriptomic changes. RESULTS Persufflated pancreata had reduced SCS time, which resulted in islets with higher glucose-stimulated insulin secretion compared to islets from SCS only pancreata. RNA sequencing of islets from persufflated pancreata identified reduced inflammatory and greater metabolic gene expression, consistent with expectations of reducing cold ischemic exposure. Portions of these transcriptional responses were not associated with time spent in SCS and were attributable to pancreatic reoxygenation. Furthermore, persufflation extended the total preservation time by 50% without any detectable decline in islet function or viability. CONCLUSIONS These data demonstrate that pancreas preservation by persufflation rather than SCS before islet isolation reduces inflammatory responses and promotes metabolic pathways in human islets, which results in improved β cell function.
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Affiliation(s)
- Amy C. Kelly
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson AZ
| | - Kate E. Smith
- Physiological Sciences, University of Arizona, Tucson AZ
| | - William G. Purvis
- Department of Surgery, Institute for Cellular Transplantation, University of Arizona, Tucson AZ
| | | | - Craig S. Weber
- Physiological Sciences, University of Arizona, Tucson AZ
| | - Amanda M. Cooksey
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson AZ
| | - Craig Hasilo
- Human Islet Transplant Laboratory, McGill University Health Centre, Montreal, Quebec, CA
| | - Steven Paraskevas
- Human Islet Transplant Laboratory, McGill University Health Centre, Montreal, Quebec, CA
| | - Thomas M. Suszynski
- Department of Surgery, Institute for Cellular Transplantation, University of Arizona, Tucson AZ
| | - Bradley P. Weegman
- Department of Surgery, Institute for Cellular Transplantation, University of Arizona, Tucson AZ
| | - Miranda J. Anderson
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson AZ
| | - Leticia E. Camacho
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson AZ
| | - Robert C. Harland
- Department of Surgery, Institute for Cellular Transplantation, University of Arizona, Tucson AZ
| | - Tom Loudovaris
- Department of Surgery, Institute for Cellular Transplantation, University of Arizona, Tucson AZ
| | - Jana Jandova
- Department of Surgery, Institute for Cellular Transplantation, University of Arizona, Tucson AZ
| | - Diana S. Molano
- Department of Surgery, Institute for Cellular Transplantation, University of Arizona, Tucson AZ
| | - Nicholas D. Price
- Department of Surgery, Institute for Cellular Transplantation, University of Arizona, Tucson AZ
| | - Ivan G. Georgiev
- Department of Surgery, Institute for Cellular Transplantation, University of Arizona, Tucson AZ
| | - William E. Scott
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Derek Manas
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - James Shaw
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Doug O’Gorman
- Clinical Islet Transplant Program, Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, CA
| | - Tatsuya Kin
- Clinical Islet Transplant Program, Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, CA
| | - Fiona M. McCarthy
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson AZ
| | - Gregory L. Szot
- Department of Surgery, University of California San Francisco, San Francisco, CA
| | - Andrew M. Posselt
- Department of Surgery, University of California San Francisco, San Francisco, CA
| | - Peter G. Stock
- Department of Surgery, University of California San Francisco, San Francisco, CA
| | | | - William J. Shapiro
- Clinical Islet Transplant Program, Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, CA
| | | | - Sean W. Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson AZ
| | - Klearchos K. Papas
- Department of Surgery, Institute for Cellular Transplantation, University of Arizona, Tucson AZ
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Kelly AC, Limesand SW. Classic solutions to a modern problem: exercise training improves metabolic disorders in offspring from fathers on a high fat diet. J Physiol 2018; 597:9-10. [PMID: 30431645 DOI: 10.1113/jp277316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Amy C Kelly
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
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Hart NJ, Weber C, Papas KK, Limesand SW, Vagner J, Lynch RM. Multivalent activation of GLP-1 and sulfonylurea receptors modulates β-cell second-messenger signaling and insulin secretion. Am J Physiol Cell Physiol 2018; 316:C48-C56. [PMID: 30404557 DOI: 10.1152/ajpcell.00209.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Linking two pharmacophores that bind different cell surface receptors into a single molecule can enhance cell-targeting specificity to cells that express the complementary receptor pair. In this report, we developed and tested a synthetic multivalent ligand consisting of glucagon-like peptide-1 (GLP-1) linked to glibenclamide (Glb) (GLP-1/Glb) for signaling efficacy in β-cells. Expression of receptors for these ligands, as a combination, is relatively specific to the β-cell in the pancreas. The multivalent GLP-1/Glb increased both intracellular cAMP and Ca2+, although Ca2+ responses were significantly depressed compared with the monomeric Glb. Moreover, GLP-1/Glb increased glucose-stimulated insulin secretion in a dose-dependent manner. However, unlike the combined monomers, GLP-1/Glb did not augment insulin secretion at nonstimulatory glucose concentrations in INS 832/13 β-cells or human islets of Langerhans. These data suggest that linking two binding elements, such as GLP-1 and Glb, into a single bivalent ligand can provide a unique functional agent targeted to β-cells.
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Affiliation(s)
| | - Craig Weber
- Department of Physiology, University of Arizona , Tucson, Arizona
| | | | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona , Tucson, Arizona.,BIO5 Institute, University of Arizona , Tucson, Arizona
| | - Josef Vagner
- BIO5 Institute, University of Arizona , Tucson, Arizona
| | - Ronald M Lynch
- Department of Physiology, University of Arizona , Tucson, Arizona.,Department of Pharmacology, University of Arizona , Tucson, Arizona.,BIO5 Institute, University of Arizona , Tucson, Arizona
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Kelly AC, Bidwell CA, Chen X, Macko AR, Anderson MJ, Limesand SW. Chronic Adrenergic Signaling Causes Abnormal RNA Expression of Proliferative Genes in Fetal Sheep Islets. Endocrinology 2018; 159:3565-3578. [PMID: 30124804 PMCID: PMC6150948 DOI: 10.1210/en.2018-00540] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 08/10/2018] [Indexed: 12/22/2022]
Abstract
Intrauterine growth restriction (IUGR) increases the risk of developing diabetes in later life, which indicates developmental programming of islets. IUGR fetuses with placental insufficiency develop hypoxemia, elevating epinephrine and norepinephrine (NE) concentrations throughout late gestation. To isolate the programming effects of chronically elevated catecholamines, NE was continuously infused into normally grown sheep fetuses for 7 days. High plasma NE concentrations suppress insulin, but after the NE infusion was terminated, persistent hypersecretion of insulin occurred. Our objective was to identify differential gene expression with RNA sequencing (RNAseq) in fetal islets after chronic adrenergic stimulation. After determining the NE-regulated genes, we identified the subset of differentially expressed genes that were common to both islets from NE fetuses and fetuses with IUGR to delineate the adrenergic-induced transcriptional responses. A portion of these genes were investigated in mouse insulinoma (Min6) cells chronically treated with epinephrine to better approximate the β-cell response. In islets from NE fetuses, RNAseq identified 321 differentially expressed genes that were overenriched for metabolic and hormone processes, and the subset of 96 differentially expressed genes common to IUGR islets were overenriched for protein digestion, vitamin metabolism, and cell replication pathways. Thirty-eight of the 96 NE-regulated IUGR genes changed similarly between models with functional enrichment for proliferation. In Min6 cells, chronic epinephrine stimulation slowed proliferation and augmented insulin secretion after treatment. These data establish molecular mechanisms underlying persistent adrenergic stimulation in hyperfunctional fetal islets and identify a subset of genes dysregulated by catecholamines in IUGR islets that may represent programming of β-cell proliferation capacity.
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Affiliation(s)
- Amy C Kelly
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
| | | | - Xiaochuan Chen
- Chongqing Key Laboratory of Forage & Herbivore, College of Animal Science and Technology, Southwest University, Chongqing, China
| | - Antoni R Macko
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
| | - Miranda J Anderson
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
- Correspondence: Sean W. Limesand, PhD, School of Animal and Comparative Biomedical Sciences, University of Arizona, 1650 East Limberlost Drive, Tucson, Arizona 85719. E-mail:
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Posont RJ, Beede KA, Limesand SW, Yates DT. Changes in myoblast responsiveness to TNFα and IL-6 contribute to decreased skeletal muscle mass in intrauterine growth restricted fetal sheep. Transl Anim Sci 2018; 2:S44-S47. [PMID: 30627704 PMCID: PMC6310364 DOI: 10.1093/tas/txy038] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 04/14/2018] [Indexed: 01/04/2023] Open
Affiliation(s)
- Robert J Posont
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE
| | - Kristin A Beede
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, AZ
| | - Dustin T Yates
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE
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Kelly AC, Camacho LE, Pendarvis K, Davenport HM, Steffens NR, Smith KE, Weber CS, Lynch RM, Papas KK, Limesand SW. Adrenergic receptor stimulation suppresses oxidative metabolism in isolated rat islets and Min6 cells. Mol Cell Endocrinol 2018; 473:136-145. [PMID: 29360563 PMCID: PMC6045463 DOI: 10.1016/j.mce.2018.01.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 01/17/2018] [Accepted: 01/18/2018] [Indexed: 01/24/2023]
Abstract
Insulin secretion is stimulated by glucose metabolism and inhibited by catecholamines through adrenergic receptor stimulation. We determined whether catecholamines suppress oxidative metabolism in β-cells through adrenergic receptors. In Min6 cells and isolated rat islets, epinephrine decreased oxygen consumption rates compared to vehicle control or co-administration of epinephrine with α2-adrenergic receptor antagonist yohimbine. Epinephrine also decreased forskolin-stimulated oxygen consumption rates, indicating cAMP dependent and independent actions. Furthermore, glucose oxidation rates were decreased with epinephrine, independent of the exocytosis of insulin, which was blocked with yohimbine. We evaluated metabolic targets through proteomic analysis after 4 h epinephrine exposure that revealed 466 differentially expressed proteins that were significantly enriched for processes including oxidative metabolism, protein turnover, exocytosis, and cell proliferation. These results demonstrate that acute α2-adrenergic stimulation suppresses glucose oxidation in β-cells independent of nutrient availability and insulin exocytosis, while cAMP concentrations are elevated. Proteomics and immunoblots revealed changes in electron transport chain proteins that were correlated with lower metabolic reducing equivalents, intracellular ATP concentrations, and altered mitochondrial membrane potential implicating a new role for adrenergic control of mitochondrial function and ultimately insulin secretion.
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Affiliation(s)
- Amy C Kelly
- School of Comparative Animal and Biomedical Sciences, University of Arizona, Tucson AZ, United States
| | - Leticia E Camacho
- School of Comparative Animal and Biomedical Sciences, University of Arizona, Tucson AZ, United States
| | - Ken Pendarvis
- School of Comparative Animal and Biomedical Sciences, University of Arizona, Tucson AZ, United States
| | - Hailey M Davenport
- School of Comparative Animal and Biomedical Sciences, University of Arizona, Tucson AZ, United States
| | - Nathan R Steffens
- School of Comparative Animal and Biomedical Sciences, University of Arizona, Tucson AZ, United States
| | - Kate E Smith
- Department of Surgery, University of Arizona, Tucson AZ, United States
| | - Craig S Weber
- Department of Physiology, University of Arizona, Tucson AZ, United States
| | - Ronald M Lynch
- Department of Physiology, University of Arizona, Tucson AZ, United States
| | - Klearchos K Papas
- Department of Surgery, University of Arizona, Tucson AZ, United States
| | - Sean W Limesand
- School of Comparative Animal and Biomedical Sciences, University of Arizona, Tucson AZ, United States.
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Smith KE, Purvis WG, Davis MA, Min CG, Cooksey AM, Weber CS, Jandova J, Price ND, Molano DS, Stanton JB, Kelly AC, Steyn LV, Lynch RM, Limesand SW, Alexander M, Lakey JRT, Seeberger K, Korbutt GS, Mueller KR, Hering BJ, McCarthy FM, Papas KK. In vitro characterization of neonatal, juvenile, and adult porcine islet oxygen demand, β-cell function, and transcriptomes. Xenotransplantation 2018; 25:e12432. [PMID: 30052287 DOI: 10.1111/xen.12432] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 04/20/2018] [Accepted: 05/24/2018] [Indexed: 12/19/2022]
Abstract
BACKGROUND There is currently a shortage of human donor pancreata which limits the broad application of islet transplantation as a treatment for type 1 diabetes. Porcine islets have demonstrated potential as an alternative source, but a study evaluating islets from different donor ages under unified protocols has yet to be conducted. METHODS Neonatal porcine islets (NPI; 1-3 days), juvenile porcine islets (JPI; 18-21 days), and adult porcine islets (API; 2+ years) were compared in vitro, including assessments of oxygen consumption rate, membrane integrity determined by FDA/PI staining, β-cell proliferation, dynamic glucose-stimulated insulin secretion, and RNA sequencing. RESULTS Oxygen consumption rate normalized to DNA was not significantly different between ages. Membrane integrity was age dependent, and API had the highest percentage of intact cells. API also had the highest glucose-stimulated insulin secretion response during a dynamic insulin secretion assay and had 50-fold higher total insulin content compared to NPI and JPI. NPI and JPI had similar glucose responsiveness, β-cell percentage, and β-cell proliferation rate. Transcriptome analysis was consistent with physiological assessments. API transcriptomes were enriched for cellular metabolic and insulin secretory pathways, while NPI exhibited higher expression of genes associated with proliferation. CONCLUSIONS The oxygen demand, membrane integrity, β-cell function and proliferation, and transcriptomes of islets from API, JPI, and NPI provide a comprehensive physiological comparison for future studies. These assessments will inform the optimal application of each age of porcine islet to expand the availability of islet transplantation.
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Affiliation(s)
- Kate E Smith
- Department of Physiological Sciences, University of Arizona, Tucson, AZ, USA.,Department of Surgery, University of Arizona, Tucson, AZ, USA
| | | | - Melissa A Davis
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Catherine G Min
- Department of Physiological Sciences, University of Arizona, Tucson, AZ, USA.,Department of Surgery, University of Arizona, Tucson, AZ, USA
| | - Amanda M Cooksey
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Craig S Weber
- Department of Physiology, University of Arizona, Tucson, AZ, USA
| | - Jana Jandova
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | | | - Diana S Molano
- Department of Surgery, University of Arizona, Tucson, AZ, USA
| | | | - Amy C Kelly
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Leah V Steyn
- Department of Surgery, University of Arizona, Tucson, AZ, USA
| | - Ronald M Lynch
- Department of Physiology, University of Arizona, Tucson, AZ, USA
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Michael Alexander
- Department of Surgery, University of California-Irvine, Orange, CA, USA
| | | | - Karen Seeberger
- Department of Surgery, Alberta Diabetes Institute, University of Alberta, Edmonton, AL, Canada
| | - Gregory S Korbutt
- Department of Surgery, Alberta Diabetes Institute, University of Alberta, Edmonton, AL, Canada
| | - Kate R Mueller
- Schulze Diabetes Institute, Department of Surgery, University of Minnesota, Minneapolis, MN, USA
| | - Bernhard J Hering
- Schulze Diabetes Institute, Department of Surgery, University of Minnesota, Minneapolis, MN, USA
| | - Fiona M McCarthy
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
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Limesand SW, Camacho LE, Kelly AC, Antolic AT. Impact of thermal stress on placental function and fetal physiology. Anim Reprod 2018; 15:886-898. [PMID: 36249845 PMCID: PMC9536067 DOI: 10.21451/1984-3143-ar2018-0056] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 05/16/2018] [Indexed: 12/03/2022] Open
Abstract
In ruminants, prolonged exposure to high ambient temperatures negatively affects placental development and function. The pursuing limitations in placental oxygen and nutrient supply between the mother and fetus slow fetal growth lowering birth weights and postnatal performance. The pregnant ewe is a long-standing animal model for the study of maternal- fetal interactions and is susceptible to naturally occurring heat stress, which causes fetal growth restriction. In the pregnant ewe, studies show that the fetus adapts to hyperthermia-induced placental insufficiency to preserve placental transport capacity of oxygen and nutrients. These adaptive responses are at the expense of normal fetal development and growth. Enlarged transplacental gradient for oxygen and glucose facilitates diffusion across the placenta, but develops by lowering fetal blood oxygen and glucose concentrations. Fetal hypoxemia and hypoglycemia slow growth and alter their metabolic and endocrine profiles. Deficits in amino acids transport across the placenta are present but are overcome by reduced fetal clearance rates, likely due to fetal hypoxemia or endocrine responses to hypoxic stress. Here, we provide an overview of the performance limitations observed in ruminants exposed to heat stress during pregnancy, but we focus our presentation on the sheep fetus in pregnancies complicated by hyperthermia-induced placental insufficiency. We define the characteristics of placental dysfunction observed in the fetus of heat stressed ewes during pregnancy and present developmental adaptations in organogenesis, metabolism, and endocrinology that are proposed to establish maladaptive situations reaching far beyond the perinatal period.
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Abstract
Placental insufficiency is a primary cause of intrauterine growth restriction (IUGR). IUGR increases the risk of developing type 2 diabetes mellitus (T2DM) throughout life, which indicates that insults from placental insufficiency impair β-cell development during the perinatal period because β-cells have a central role in the regulation of glucose tolerance. The severely IUGR fetal pancreas is characterized by smaller islets, less β-cells, and lower insulin secretion. Because of the important associations among impaired islet growth, β-cell dysfunction, impaired fetal growth, and the propensity for T2DM, significant progress has been made in understanding the pathophysiology of IUGR and programing events in the fetal endocrine pancreas. Animal models of IUGR replicate many of the observations in severe cases of human IUGR and allow us to refine our understanding of the pathophysiology of developmental and functional defects in islet from IUGR fetuses. Almost all models demonstrate a phenotype of progressive loss of β-cell mass and impaired β-cell function. This review will first provide evidence of impaired human islet development and β-cell function associated with IUGR and the impact on glucose homeostasis including the development of glucose intolerance and diabetes in adulthood. We then discuss evidence for the mechanisms regulating β-cell mass and insulin secretion in the IUGR fetus, including the role of hypoxia, catecholamines, nutrients, growth factors, and pancreatic vascularity. We focus on recent evidence from experimental interventions in established models of IUGR to understand better the pathophysiological mechanisms linking placental insufficiency with impaired islet development and β-cell function.
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Affiliation(s)
- Brit H Boehmer
- Department of PediatricsPerinatal Research Center, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Sean W Limesand
- School of Animal and Comparative Biomedical SciencesUniversity of Arizona, Tucson, Arizona, USA
| | - Paul J Rozance
- Department of PediatricsPerinatal Research Center, University of Colorado School of Medicine, Aurora, Colorado, USA
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Smith KE, Kelly AC, Min CG, Weber CS, McCarthy FM, Steyn LV, Badarinarayana V, Stanton JB, Kitzmann JP, Strop P, Gruessner AC, Lynch RM, Limesand SW, Papas KK. Acute Ischemia Induced by High-Density Culture Increases Cytokine Expression and Diminishes the Function and Viability of Highly Purified Human Islets of Langerhans. Transplantation 2017; 101:2705-2712. [PMID: 28263224 PMCID: PMC6319561 DOI: 10.1097/tp.0000000000001714] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 01/24/2017] [Accepted: 02/16/2017] [Indexed: 11/25/2022]
Abstract
BACKGROUND Encapsulation devices have the potential to enable cell-based insulin replacement therapies (such as human islet or stem cell-derived β cell transplantation) without immunosuppression. However, reasonably sized encapsulation devices promote ischemia due to high β cell densities creating prohibitively large diffusional distances for nutrients. It is hypothesized that even acute ischemic exposure will compromise the therapeutic potential of cell-based insulin replacement. In this study, the acute effects of high-density ischemia were investigated in human islets to develop a detailed profile of early ischemia induced changes and targets for intervention. METHODS Human islets were exposed in a pairwise model simulating high-density encapsulation to normoxic or ischemic culture for 12 hours, after which viability and function were measured. RNA sequencing was conducted to assess transcriptome-wide changes in gene expression. RESULTS Islet viability after acute ischemic exposure was reduced compared to normoxic culture conditions (P < 0.01). Insulin secretion was also diminished, with ischemic β cells losing their insulin secretory response to stimulatory glucose levels (P < 0.01). RNA sequencing revealed 657 differentially expressed genes following ischemia, with many that are associated with increased inflammatory and hypoxia-response signaling and decreased nutrient transport and metabolism. CONCLUSIONS In order for cell-based insulin replacement to be applied as a treatment for type 1 diabetes, oxygen and nutrient delivery to β cells will need to be maintained. We demonstrate that even brief ischemic exposure such as would be experienced in encapsulation devices damages islet viability and β cell function and leads to increased inflammatory signaling.
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Affiliation(s)
- Kate E. Smith
- Department of Surgery, University of Arizona, Tucson, AZ
- Department of Physiological Sciences GIDP, University of Arizona, Tucson, AZ
| | - Amy C. Kelly
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ
| | - Catherine G. Min
- Department of Surgery, University of Arizona, Tucson, AZ
- Department of Physiological Sciences GIDP, University of Arizona, Tucson, AZ
| | - Craig S. Weber
- Department of Physiology, University of Arizona, Tucson, AZ
| | - Fiona M. McCarthy
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ
| | - Leah V. Steyn
- Department of Surgery, University of Arizona, Tucson, AZ
| | | | | | | | - Peter Strop
- Sanofi-Aventis Group, Tucson, AZ
- Icagen, Inc., Tucson, AZ
| | | | | | - Sean W. Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ
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Limesand SW, Rozance PJ. Fetal adaptations in insulin secretion result from high catecholamines during placental insufficiency. J Physiol 2017; 595:5103-5113. [PMID: 28194805 DOI: 10.1113/jp273324] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 02/06/2017] [Indexed: 12/13/2022] Open
Abstract
Placental insufficiency and intrauterine growth restriction (IUGR) of the fetus affects approximately 8% of all pregnancies and is associated with short- and long-term disturbances in metabolism. In pregnant sheep, experimental models with a small, defective placenta that restricts delivery of nutrients and oxygen to the fetus result in IUGR. Low blood oxygen concentrations increase fetal plasma catecholamine concentrations, which lower fetal insulin concentrations. All of these observations in sheep models with placental insufficiency are consistent with cases of human IUGR. We propose that sustained high catecholamine concentrations observed in the IUGR fetus produce developmental adaptations in pancreatic β-cells that impair fetal insulin secretion. Experimental evidence supporting this hypothesis shows that chronic elevation in circulating catecholamines in IUGR fetuses persistently inhibits insulin concentrations and secretion. Elevated catecholamines also allow for maintenance of a normal fetal basal metabolic rate despite low fetal insulin and glucose concentrations while suppressing fetal growth. Importantly, a compensatory augmentation in insulin secretion occurs following inhibition or cessation of catecholamine signalling in IUGR fetuses. This finding has been replicated in normally grown sheep fetuses following a 7-day noradrenaline (norepinephrine) infusion. Together, these programmed effects will potentially create an imbalance between insulin secretion and insulin-stimulated glucose utilization in the neonate which probably explains the transient hyperinsulinism and hypoglycaemia in some IUGR infants.
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Affiliation(s)
- Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Paul J Rozance
- Perinatal Research Center, University of Colorado School of Medicine, Aurora, CO, USA
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38
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Camacho LE, Chen X, Hay WW, Limesand SW. Enhanced insulin secretion and insulin sensitivity in young lambs with placental insufficiency-induced intrauterine growth restriction. Am J Physiol Regul Integr Comp Physiol 2017; 313:R101-R109. [PMID: 28490449 PMCID: PMC5582953 DOI: 10.1152/ajpregu.00068.2017] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 05/03/2017] [Accepted: 05/08/2017] [Indexed: 11/22/2022]
Abstract
Intrauterine growth restriction (IUGR) is associated with persistent metabolic complications, but information is limited for IUGR infants. We determined glucose-stimulated insulin secretion (GSIS) and insulin sensitivity in young lambs with placental insufficiency-induced IUGR. Lambs with hyperthermia-induced IUGR (n = 7) were compared with control lambs (n = 8). GSIS was measured at 8 ± 1 days of age, and at 15 ± 1 days, body weight-specific glucose utilization rates were measured with radiolabeled d-glucose during a hyperinsulinemic-euglycemic clamp (HEC). IUGR lambs weighed 23% less (P < 0.05) than controls at birth. Fasting plasma glucose and insulin concentrations were not different between IUGR and controls for either study. First-phase insulin secretion was enhanced 2.3-fold in IUGR lambs compared with controls. However, second-phase insulin concentrations, glucose-potentiated arginine-stimulated insulin secretion, and β-cell mass were not different, indicating that IUGR β-cells have an intrinsic enhancement in acute GSIS. Compared with controls, IUGR lambs had higher body weight-specific glucose utilization rates and greater insulin sensitivity at fasting (1.6-fold) and hyperinsulinemic periods (2.4-fold). Improved insulin sensitivity for glucose utilization was not due to differences in skeletal muscle insulin receptor and glucose transporters 1 and 4 concentrations. Plasma lactate concentrations during HEC were elevated in IUGR lambs compared with controls, but no differences were found for glycogen content or citrate synthase activity in liver and muscle. Greater insulin sensitivity for glucose utilization and enhanced acute GSIS in young lambs are predicted from fetal studies but may promote conditions that exaggerate glucose disposal and lead to episodes of hypoglycemia in IUGR infants.
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Affiliation(s)
- Leticia E Camacho
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
| | - Xiaochuan Chen
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona.,Chongqing Key Laboratory of Forage & Herbivore, College of Animal Science and Technology, Southwest University, Chongqing, China; and
| | - William W Hay
- Perinatal Research Center, University of Colorado School of Medicine, Aurora, Colorado
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona;
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Kelly AC, Bidwell CA, McCarthy FM, Taska DJ, Anderson MJ, Camacho LE, Limesand SW. RNA Sequencing Exposes Adaptive and Immune Responses to Intrauterine Growth Restriction in Fetal Sheep Islets. Endocrinology 2017; 158:743-755. [PMID: 28200173 PMCID: PMC5460795 DOI: 10.1210/en.2016-1901] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 02/03/2017] [Indexed: 11/19/2022]
Abstract
The risk of type 2 diabetes is increased in children and adults who exhibited fetal growth restriction. Placental insufficiency and intrauterine growth restriction (IUGR) are common obstetrical complications associated with fetal hypoglycemia and hypoxia that reduce the β-cell mass and insulin secretion. In the present study, we have defined the underlying mechanisms of reduced growth and proliferation, impaired metabolism, and defective insulin secretion previously established as complications in islets from IUGR fetuses. In an IUGR sheep model that recapitulates human IUGR, high-throughput RNA sequencing showed the transcriptome of islets isolated from IUGR and control sheep fetuses and identified the transcripts that underlie β-cell dysfunction. Functional analysis expanded mechanisms involved in reduced proliferation and dysregulated metabolism that include specific cell cycle regulators and growth factors and mitochondrial, antioxidant, and exocytotic genes. These data also identified immune responses, wnt signaling, adaptive stress responses, and the proteasome as mechanisms of β-cell dysfunction. The reduction of immune-related gene expression did not reflect a change in macrophage density within IUGR islets. The present study reports the islet transcriptome in fetal sheep and established processes that limit insulin secretion and β-cell growth in fetuses with IUGR, which could explain the susceptibility to premature islet failure in adulthood. Islet dysfunction formed by intrauterine growth restriction increases the risk for diabetes.
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Affiliation(s)
- Amy C. Kelly
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona 85719
| | | | - Fiona M. McCarthy
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona 85719
| | - David J. Taska
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona 85719
| | - Miranda J. Anderson
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona 85719
| | - Leticia E. Camacho
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona 85719
| | - Sean W. Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona 85719
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40
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Harris SE, De Blasio MJ, Davis MA, Kelly AC, Davenport HM, Wooding FBP, Blache D, Meredith D, Anderson M, Fowden AL, Limesand SW, Forhead AJ. Hypothyroidism in utero stimulates pancreatic beta cell proliferation and hyperinsulinaemia in the ovine fetus during late gestation. J Physiol 2017; 595:3331-3343. [PMID: 28144955 PMCID: PMC5451716 DOI: 10.1113/jp273555] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 01/11/2017] [Indexed: 12/17/2022] Open
Abstract
Key points Thyroid hormones are important regulators of growth and maturation before birth, although the extent to which their actions are mediated by insulin and the development of pancreatic beta cell mass is unknown. Hypothyroidism in fetal sheep induced by removal of the thyroid gland caused asymmetric organ growth, increased pancreatic beta cell mass and proliferation, and was associated with increased circulating concentrations of insulin and leptin. In isolated fetal sheep islets studied in vitro, thyroid hormones inhibited beta cell proliferation in a dose‐dependent manner, while high concentrations of insulin and leptin stimulated proliferation. The developing pancreatic beta cell is therefore sensitive to thyroid hormone, insulin and leptin before birth, with possible consequences for pancreatic function in fetal and later life. The findings of this study highlight the importance of thyroid hormones during pregnancy for normal development of the fetal pancreas.
Abstract Development of pancreatic beta cell mass before birth is essential for normal growth of the fetus and for long‐term control of carbohydrate metabolism in postnatal life. Thyroid hormones are also important regulators of fetal growth, and the present study tested the hypotheses that thyroid hormones promote beta cell proliferation in the fetal ovine pancreatic islets, and that growth retardation in hypothyroid fetal sheep is associated with reductions in pancreatic beta cell mass and circulating insulin concentration in utero. Organ growth and pancreatic islet cell proliferation and mass were examined in sheep fetuses following removal of the thyroid gland in utero. The effects of triiodothyronine (T3), insulin and leptin on beta cell proliferation rates were determined in isolated fetal ovine pancreatic islets in vitro. Hypothyroidism in the sheep fetus resulted in an asymmetric pattern of organ growth, pancreatic beta cell hyperplasia, and elevated plasma insulin and leptin concentrations. In pancreatic islets isolated from intact fetal sheep, beta cell proliferation in vitro was reduced by T3 in a dose‐dependent manner and increased by insulin at high concentrations only. Leptin induced a bimodal response whereby beta cell proliferation was suppressed at the lowest, and increased at the highest, concentrations. Therefore, proliferation of beta cells isolated from the ovine fetal pancreas is sensitive to physiological concentrations of T3, insulin and leptin. Alterations in these hormones may be responsible for the increased beta cell proliferation and mass observed in the hypothyroid sheep fetus and may have consequences for pancreatic function in later life. Thyroid hormones are important regulators of growth and maturation before birth, although the extent to which their actions are mediated by insulin and the development of pancreatic beta cell mass is unknown. Hypothyroidism in fetal sheep induced by removal of the thyroid gland caused asymmetric organ growth, increased pancreatic beta cell mass and proliferation, and was associated with increased circulating concentrations of insulin and leptin. In isolated fetal sheep islets studied in vitro, thyroid hormones inhibited beta cell proliferation in a dose‐dependent manner, while high concentrations of insulin and leptin stimulated proliferation. The developing pancreatic beta cell is therefore sensitive to thyroid hormone, insulin and leptin before birth, with possible consequences for pancreatic function in fetal and later life. The findings of this study highlight the importance of thyroid hormones during pregnancy for normal development of the fetal pancreas.
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Affiliation(s)
- Shelley E Harris
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Miles J De Blasio
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Melissa A Davis
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, 85721, USA
| | - Amy C Kelly
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, 85721, USA
| | - Hailey M Davenport
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, 85721, USA
| | - F B Peter Wooding
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Dominique Blache
- School of Animal Biology, University of Western Australia, 6009, Crawley, Australia
| | - David Meredith
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Miranda Anderson
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, 85721, USA
| | - Abigail L Fowden
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, 85721, USA
| | - Alison J Forhead
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK.,Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
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Chen X, Kelly AC, Yates DT, Macko AR, Lynch RM, Limesand SW. Islet adaptations in fetal sheep persist following chronic exposure to high norepinephrine. J Endocrinol 2017; 232:285-295. [PMID: 27888197 PMCID: PMC5173394 DOI: 10.1530/joe-16-0445] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 11/25/2016] [Indexed: 11/08/2022]
Abstract
Complications in pregnancy elevate fetal norepinephrine (NE) concentrations. Previous studies in NE-infused sheep fetuses revealed that sustained exposure to high NE resulted in lower expression of α2-adrenergic receptors in islets and increased insulin secretion responsiveness after acutely terminating the NE infusion. In this study, we determined if the compensatory increase in insulin secretion after chronic elevation of NE is independent of hyperglycemia in sheep fetuses and whether it is persistent in conjunction with islet desensitization to NE. After an initial assessment of glucose-stimulated insulin secretion (GSIS) at 129 ± 1 days of gestation, fetuses were continuously infused for seven days with NE and maintained at euglycemia with a maternal insulin infusion. Fetal GSIS studies were performed again on days 8 and 12. Adrenergic sensitivity was determined in pancreatic islets collected at day 12. NE infusion increased (P < 0.01) fetal plasma NE concentrations and lowered (P < 0.01) basal insulin concentrations compared to vehicle-infused controls. GSIS was 1.8-fold greater (P < 0.05) in NE-infused fetuses compared to controls at both one and five days after discontinuing the infusion. Glucose-potentiated arginine-induced insulin secretion was also enhanced (P < 0.01) in NE-infused fetuses. Maximum GSIS in islets isolated from NE-infused fetuses was 1.6-fold greater (P < 0.05) than controls, but islet insulin content and intracellular calcium signaling were not different between treatments. The half-maximal inhibitory concentration for NE was 2.6-fold greater (P < 0.05) in NE-infused islets compared to controls. These findings show that chronic NE exposure and not hyperglycemia produce persistent adaptations in pancreatic islets that augment β-cell responsiveness in part through decreased adrenergic sensitivity.
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Affiliation(s)
- Xiaochuan Chen
- Chongqing Key Laboratory of Forage & HerbivoreCollege of Animal Science and Technology, Southwest University, Chongqing, China
- School of Animal and Comparative Biomedical SciencesUniversity of Arizona, Tucson, Arizona, USA
| | - Amy C Kelly
- School of Animal and Comparative Biomedical SciencesUniversity of Arizona, Tucson, Arizona, USA
| | - Dustin T Yates
- School of Animal and Comparative Biomedical SciencesUniversity of Arizona, Tucson, Arizona, USA
| | - Antoni R Macko
- School of Animal and Comparative Biomedical SciencesUniversity of Arizona, Tucson, Arizona, USA
| | - Ronald M Lynch
- Department of PhysiologyUniversity of Arizona, Tucson, Arizona, USA
| | - Sean W Limesand
- School of Animal and Comparative Biomedical SciencesUniversity of Arizona, Tucson, Arizona, USA
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42
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Benjamin JS, Culpepper CB, Brown LD, Wesolowski SR, Jonker SS, Davis MA, Limesand SW, Wilkening RB, Hay WW, Rozance PJ. Chronic anemic hypoxemia attenuates glucose-stimulated insulin secretion in fetal sheep. Am J Physiol Regul Integr Comp Physiol 2017; 312:R492-R500. [PMID: 28100476 PMCID: PMC5407078 DOI: 10.1152/ajpregu.00484.2016] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 01/04/2017] [Accepted: 01/11/2017] [Indexed: 01/15/2023]
Abstract
Fetal insulin secretion is inhibited by acute hypoxemia. The relationship between prolonged hypoxemia and insulin secretion, however, is less well defined. To test the hypothesis that prolonged fetal hypoxemia impairs insulin secretion, studies were performed in sheep fetuses that were bled to anemic conditions for 9 ± 0 days (anemic, n = 19) and compared with control fetuses (n = 15). Arterial hematocrit and oxygen content were 34% and 52% lower, respectively, in anemic vs. control fetuses (P < 0.0001). Plasma glucose concentrations were 21% higher in the anemic group (P < 0.05). Plasma norepinephrine and cortisol concentrations increased 70% in the anemic group (P < 0.05). Glucose-, arginine-, and leucine-stimulated insulin secretion all were lower (P < 0.05) in anemic fetuses. No differences in pancreatic islet size or β-cell mass were found. In vitro, isolated islets from anemic fetuses secreted insulin in response to glucose and leucine as well as control fetal islets. These findings indicate a functional islet defect in anemic fetuses, which likely involves direct effects of low oxygen and/or increased norepinephrine on insulin release. In pregnancies complicated by chronic fetal hypoxemia, increasing fetal oxygen concentrations may improve insulin secretion.
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Affiliation(s)
- Joshua S Benjamin
- Perinatal Research Center, Department of Pediatrics, University of Colorado Denver School of Medicine, Aurora, Colorado
| | - Christine B Culpepper
- Perinatal Research Center, Department of Pediatrics, University of Colorado Denver School of Medicine, Aurora, Colorado
| | - Laura D Brown
- Perinatal Research Center, Department of Pediatrics, University of Colorado Denver School of Medicine, Aurora, Colorado.,Center for Women's Health Research, University of Colorado Denver School of Medicine, Aurora, Colorado
| | - Stephanie R Wesolowski
- Perinatal Research Center, Department of Pediatrics, University of Colorado Denver School of Medicine, Aurora, Colorado.,Center for Women's Health Research, University of Colorado Denver School of Medicine, Aurora, Colorado
| | - Sonnet S Jonker
- Knight Cardiovascular Institute Center for Developmental Health, Oregon Health & Science University, Portland, Oregon; and
| | - Melissa A Davis
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona
| | - Randall B Wilkening
- Perinatal Research Center, Department of Pediatrics, University of Colorado Denver School of Medicine, Aurora, Colorado
| | - William W Hay
- Perinatal Research Center, Department of Pediatrics, University of Colorado Denver School of Medicine, Aurora, Colorado
| | - Paul J Rozance
- Perinatal Research Center, Department of Pediatrics, University of Colorado Denver School of Medicine, Aurora, Colorado; .,Center for Women's Health Research, University of Colorado Denver School of Medicine, Aurora, Colorado
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Barry JS, Davidsen ML, Limesand SW, Galan HL, Friedman JE, Regnault TRH, Hay WW. Developmental Changes in Ovine Myocardial Glucose Transporters and Insulin Signaling Following Hyperthermia-Induced Intrauterine Fetal Growth Restriction. Exp Biol Med (Maywood) 2016; 231:566-75. [PMID: 16636305 DOI: 10.1177/153537020623100511] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Developmental changes in ovine myocardial glucose transporters and insulin signaling following hyperthermia-induced intrauterine fetal growth restriction (IUGR) were the focus of our study. Our objective was to test the hypothesis that the fetal ovine myocardium adapts during an IUGR gestation by increasing glucose transporter protein expression, plasma membrane-bound glucose transporter protein concentrations, and insulin signal transduction protein concentrations. Growth measurements and whole heart tissue were obtained at 55 days gestational age (dGA), 90 dGA, and 135 dGA (term = 145 dGA) in fetuses from control (C) and hyperthermic (HT) pregnant sheep. Additionally, in 135 dGA animals, arterial blood was obtained and Doppler ultrasound was used to determine umbilical artery systolic (S) and diastolic (D) flow velocity waveform profiles to calculate pulsatility (S – D/mean) and resistance (S – D/S) indices. Myocardial Glut-1, Glut-4, insulin signal transduction proteins involved in Glut-4 translocation, and glycogen content were measured. Compared to age-matched controls, HT 90-dGA fetal body weights and HT 135-dGA fetal weights and gross heart weights were lower. Heart weights as a percent of body weights were similar between C and HT sheep at 135 dGA. HT 135-dGA animals had (i) lower fetal arterial plasma glucose and insulin concentrations, (ii) lower arterial blood oxygen content and higher plasma lactate concentrations, (iii) higher myocardial Glut-4 plasma membrane (PM) protein and insulin receptor β protein (IRβ) concentrations, (iv) higher myocardial glycogen content, and (v) higher umbilical artery Doppler pulsatility and resistance indices. The HT ovine fetal myocardium adapts to reduced circulating glucose and insulin concentrations by increasing plasma membrane Glut-4 and IRβ protein concentrations. The increased myocardial Glut-4 PM and IRβ protein concentrations likely contribute to or increase the intracellular delivery of glucose and, together with the increased lactate concentrations, enhance glycogen synthesis, which allows for maintained myocardial growth commensurate with fetal body growth.
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Affiliation(s)
- James S Barry
- Department of Pediatrics, Section of Neonatology, University of Colorado School of Medicine, The Children's Hospital, 1056 East 19th Avenue, Box B070, Denver, CO 80218, USA.
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Brown LD, Davis M, Wai S, Wesolowski SR, Hay WW, Limesand SW, Rozance PJ. Chronically Increased Amino Acids Improve Insulin Secretion, Pancreatic Vascularity, and Islet Size in Growth-Restricted Fetal Sheep. Endocrinology 2016; 157:3788-3799. [PMID: 27501184 PMCID: PMC5045508 DOI: 10.1210/en.2016-1328] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Placental insufficiency is associated with reduced supply of amino acids to the fetus and leads to intrauterine growth restriction (IUGR). IUGR fetuses are characterized by lower glucose-stimulated insulin secretion, smaller pancreatic islets with less β-cells, and impaired pancreatic vascularity. To test whether supplemental amino acids infused into the IUGR fetus could improve these complications of IUGR we used acute (hours) and chronic (11 d) direct fetal amino acid infusions into a sheep model of placental insufficiency and IUGR near the end of gestation. IUGR fetuses had attenuated acute amino acid-stimulated insulin secretion compared with control fetuses. These results were confirmed in isolated IUGR pancreatic islets. After the chronic fetal amino acid infusion, fetal glucose-stimulated insulin secretion and islet size were restored to control values. These changes were associated with normalization of fetal pancreatic vascularity and higher fetal pancreatic vascular endothelial growth factor A protein concentrations. These results demonstrate that decreased fetal amino acid supply contributes to the pathogenesis of pancreatic islet defects in IUGR. Moreover, the results show that pancreatic islets in IUGR fetuses retain their ability to respond to increased amino acids near the end of gestation after chronic fetal growth restriction.
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Affiliation(s)
- Laura D Brown
- Perinatal Research Center (L.D.B., S.W., W.W.H., P.J.R.), University of Colorado School of Medicine, Aurora, Colorado 80045; School of Animal and Comparative Biomedical Sciences (M.D., S.W.L.), University of Arizona, Tucson, Arizona 85719; and Center for Women's Health Research (L.D.B., S.R.W., P.J.R.), University of Colorado School of Medicine, Aurora, Colorado 80045
| | - Melissa Davis
- Perinatal Research Center (L.D.B., S.W., W.W.H., P.J.R.), University of Colorado School of Medicine, Aurora, Colorado 80045; School of Animal and Comparative Biomedical Sciences (M.D., S.W.L.), University of Arizona, Tucson, Arizona 85719; and Center for Women's Health Research (L.D.B., S.R.W., P.J.R.), University of Colorado School of Medicine, Aurora, Colorado 80045
| | - Sandra Wai
- Perinatal Research Center (L.D.B., S.W., W.W.H., P.J.R.), University of Colorado School of Medicine, Aurora, Colorado 80045; School of Animal and Comparative Biomedical Sciences (M.D., S.W.L.), University of Arizona, Tucson, Arizona 85719; and Center for Women's Health Research (L.D.B., S.R.W., P.J.R.), University of Colorado School of Medicine, Aurora, Colorado 80045
| | - Stephanie R Wesolowski
- Perinatal Research Center (L.D.B., S.W., W.W.H., P.J.R.), University of Colorado School of Medicine, Aurora, Colorado 80045; School of Animal and Comparative Biomedical Sciences (M.D., S.W.L.), University of Arizona, Tucson, Arizona 85719; and Center for Women's Health Research (L.D.B., S.R.W., P.J.R.), University of Colorado School of Medicine, Aurora, Colorado 80045
| | - William W Hay
- Perinatal Research Center (L.D.B., S.W., W.W.H., P.J.R.), University of Colorado School of Medicine, Aurora, Colorado 80045; School of Animal and Comparative Biomedical Sciences (M.D., S.W.L.), University of Arizona, Tucson, Arizona 85719; and Center for Women's Health Research (L.D.B., S.R.W., P.J.R.), University of Colorado School of Medicine, Aurora, Colorado 80045
| | - Sean W Limesand
- Perinatal Research Center (L.D.B., S.W., W.W.H., P.J.R.), University of Colorado School of Medicine, Aurora, Colorado 80045; School of Animal and Comparative Biomedical Sciences (M.D., S.W.L.), University of Arizona, Tucson, Arizona 85719; and Center for Women's Health Research (L.D.B., S.R.W., P.J.R.), University of Colorado School of Medicine, Aurora, Colorado 80045
| | - Paul J Rozance
- Perinatal Research Center (L.D.B., S.W., W.W.H., P.J.R.), University of Colorado School of Medicine, Aurora, Colorado 80045; School of Animal and Comparative Biomedical Sciences (M.D., S.W.L.), University of Arizona, Tucson, Arizona 85719; and Center for Women's Health Research (L.D.B., S.R.W., P.J.R.), University of Colorado School of Medicine, Aurora, Colorado 80045
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45
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Hay WW, Brown LD, Rozance PJ, Wesolowski SR, Limesand SW. Challenges in nourishing the intrauterine growth-restricted foetus - Lessons learned from studies in the intrauterine growth-restricted foetal sheep. Acta Paediatr 2016; 105:881-9. [PMID: 27028695 DOI: 10.1111/apa.13413] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 02/24/2016] [Accepted: 03/29/2016] [Indexed: 12/11/2022]
Abstract
UNLABELLED Previous attempts to improve growth and development of the intrauterine growth-restricted (IUGR) foetus during pregnancy have not worked or caused harm. Our research identifies tissue-specific mechanisms underlying foetal growth restriction and then tests strategies to improve growth and ameliorate many of the metabolic problems before the infant is born. The goal of our studies is to reduce the impact of foetal growth restriction at critical stages of development on the lifelong complications of IUGR offspring. CONCLUSION Defining specific mechanisms that cause growth restriction in the foetus might identify specific nutrients and hormones that could be given to the mother to improve foetal growth and reduce metabolic complications, using strategies first tested in our IUGR animal model.
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Affiliation(s)
- William W. Hay
- Perinatal Research Center; University of Colorado School of Medicine; Aurora CO USA
| | - Laura D. Brown
- Perinatal Research Center; University of Colorado School of Medicine; Aurora CO USA
| | - Paul J. Rozance
- Perinatal Research Center; University of Colorado School of Medicine; Aurora CO USA
| | | | - Sean W. Limesand
- School of Animal and Comparative Biomedical Sciences; University of Arizona; Tucson AZ USA
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Macko AR, Yates DT, Chen X, Shelton LA, Kelly AC, Davis MA, Camacho LE, Anderson MJ, Limesand SW. Adrenal Demedullation and Oxygen Supplementation Independently Increase Glucose-Stimulated Insulin Concentrations in Fetal Sheep With Intrauterine Growth Restriction. Endocrinology 2016; 157:2104-15. [PMID: 26937714 PMCID: PMC4870878 DOI: 10.1210/en.2015-1850] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In pregnancies complicated by placental insufficiency and intrauterine growth restriction (IUGR), fetal glucose and oxygen concentrations are reduced, whereas plasma norepinephrine and epinephrine concentrations are elevated throughout the final third of gestation. Here we study the effects of chronic hypoxemia and hypercatecholaminemia on β-cell function in fetal sheep with placental insufficiency-induced IUGR that is produced by maternal hyperthermia. IUGR and control fetuses underwent a sham (intact) or bilateral adrenal demedullation (AD) surgical procedure at 0.65 gestation. As expected, AD-IUGR fetuses had lower norepinephrine concentrations than intact-IUGR fetuses despite being hypoxemic and hypoglycemic. Placental insufficiency reduced fetal weights, but the severity of IUGR was less with AD. Although basal plasma insulin concentrations were lower in intact-IUGR and AD-IUGR fetuses compared with intact-controls, glucose-stimulated insulin concentrations were greater in AD-IUGR fetuses compared with intact-IUGR fetuses. Interestingly, AD-controls had lower glucose- and arginine-stimulated insulin concentrations than intact-controls, but AD-IUGR and AD-control insulin responses were not different. To investigate chronic hypoxemia in the IUGR fetus, arterial oxygen tension was increased to normal levels by increasing the maternal inspired oxygen fraction. Oxygenation of IUGR fetuses enhanced glucose-stimulated insulin concentrations 3.3-fold in intact-IUGR and 1.7-fold in AD-IUGR fetuses but did not lower norepinephrine and epinephrine concentrations. Together these findings show that chronic hypoxemia and hypercatecholaminemia have distinct but complementary roles in the suppression of β-cell responsiveness in IUGR fetuses.
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Affiliation(s)
- Antoni R Macko
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona 85719
| | - Dustin T Yates
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona 85719
| | - Xiaochuan Chen
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona 85719
| | - Leslie A Shelton
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona 85719
| | - Amy C Kelly
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona 85719
| | - Melissa A Davis
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona 85719
| | - Leticia E Camacho
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona 85719
| | - Miranda J Anderson
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona 85719
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona 85719
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Yates DT, Cadaret CN, Beede KA, Riley HE, Macko AR, Anderson MJ, Camacho LE, Limesand SW. Intrauterine growth-restricted sheep fetuses exhibit smaller hindlimb muscle fibers and lower proportions of insulin-sensitive Type I fibers near term. Am J Physiol Regul Integr Comp Physiol 2016; 310:R1020-9. [PMID: 27053651 DOI: 10.1152/ajpregu.00528.2015] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/29/2016] [Indexed: 01/02/2023]
Abstract
Intrauterine growth restriction (IUGR) reduces muscle mass and insulin sensitivity in offspring. Insulin sensitivity varies among muscle fiber types, with Type I fibers being most sensitive. Differences in fiber-type ratios are associated with insulin resistance in adults, and thus we hypothesized that near-term IUGR sheep fetuses exhibit reduced size and proportions of Type I fibers. Placental insufficiency-induced IUGR fetuses were ∼54% smaller (P < 0.05) than controls and exhibited hypoxemia and hypoglycemia, which contributed to 6.9-fold greater (P < 0.05) plasma norepinephrine and ∼53% lower (P < 0.05) plasma insulin concentrations. IUGR semitendinosus muscles contained less (P < 0.05) myosin heavy chain-I protein (MyHC-I) and proportionally fewer (P < 0.05) Type I and Type I/IIa fibers than controls, but MyHC-II protein concentrations, Type II fibers, and Type IIx fibers were not different. IUGR biceps femoris muscles exhibited similar albeit less dramatic differences in fiber type proportions. Type I and IIa fibers are more responsive to adrenergic and insulin regulation than Type IIx and may be more profoundly impaired by the high catecholamines and low insulin in our IUGR fetuses, leading to their proportional reduction. In both muscles, fibers of each type were uniformly smaller (P < 0.05) in IUGR fetuses than controls, which indicates that fiber hypertrophy is not dependent on type but rather on other factors such as myoblast differentiation or protein synthesis. Together, our findings show that IUGR fetal muscles develop smaller fibers and have proportionally fewer Type I fibers, which is indicative of developmental adaptations that may help explain the link between IUGR and adulthood insulin resistance.
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Affiliation(s)
- Dustin T Yates
- Department of Animal Science, University of Nebraska, Lincoln, Nebraska; and School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona
| | - Caitlin N Cadaret
- Department of Animal Science, University of Nebraska, Lincoln, Nebraska; and
| | - Kristin A Beede
- Department of Animal Science, University of Nebraska, Lincoln, Nebraska; and
| | - Hannah E Riley
- Department of Animal Science, University of Nebraska, Lincoln, Nebraska; and
| | - Antoni R Macko
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona
| | - Miranda J Anderson
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona
| | - Leticia E Camacho
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona
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48
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Affiliation(s)
- Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona 85719
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49
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Rozance PJ, Anderson M, Martinez M, Fahy A, Macko AR, Kailey J, Seedorf GJ, Abman SH, Hay WW, Limesand SW. Placental insufficiency decreases pancreatic vascularity and disrupts hepatocyte growth factor signaling in the pancreatic islet endothelial cell in fetal sheep. Diabetes 2015; 64:555-64. [PMID: 25249573 PMCID: PMC4303968 DOI: 10.2337/db14-0462] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Hepatocyte growth factor (HGF) and vascular endothelial growth factor A (VEGFA) are paracrine hormones that mediate communication between pancreatic islet endothelial cells (ECs) and β-cells. Our objective was to determine the impact of intrauterine growth restriction (IUGR) on pancreatic vascularity and paracrine signaling between the EC and β-cell. Vessel density was less in IUGR pancreata than in controls. HGF concentrations were also lower in islet EC-conditioned media (ECCM) from IUGR, and islets incubated with control islet ECCM responded by increasing insulin content, which was absent with IUGR ECCM. The effect of ECCM on islet insulin content was blocked with an inhibitory anti-HGF antibody. The HGF receptor was not different between control and IUGR islets, but VEGFA was lower and the high-affinity VEGF receptor was higher in IUGR islets and ECs, respectively. These findings show that paracrine actions from ECs increase islet insulin content, and in IUGR ECs, secretion of HGF was diminished. Given the potential feed-forward regulation of β-cell VEGFA and islet EC HGF, these two growth factors are highly integrated in normal pancreatic islet development, and this regulation is decreased in IUGR fetuses, resulting in lower pancreatic islet insulin concentrations and insulin secretion.
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Affiliation(s)
- Paul J Rozance
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO Perinatal Research Center, University of Colorado School of Medicine, Aurora, CO
| | - Miranda Anderson
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ
| | - Marina Martinez
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ
| | - Anna Fahy
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ
| | - Antoni R Macko
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ
| | - Jenai Kailey
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO Perinatal Research Center, University of Colorado School of Medicine, Aurora, CO
| | - Gregory J Seedorf
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO Pediatric Heart Lung Center, University of Colorado School of Medicine, Aurora, CO
| | - Steven H Abman
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO Pediatric Heart Lung Center, University of Colorado School of Medicine, Aurora, CO
| | - William W Hay
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO Pediatric Heart Lung Center, University of Colorado School of Medicine, Aurora, CO
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ
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Steyn LV, Ananthakrishnan K, Anderson MJ, Patek R, Kelly A, Vagner J, Lynch RM, Limesand SW. A Synthetic Heterobivalent Ligand Composed of Glucagon-Like Peptide 1 and Yohimbine Specifically Targets β Cells Within the Pancreas. Mol Imaging Biol 2015; 17:461-70. [PMID: 25604385 DOI: 10.1007/s11307-014-0817-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 12/11/2014] [Accepted: 12/18/2014] [Indexed: 12/15/2022]
Abstract
PURPOSE β Cell specificity for a heterobivalent ligand composed of glucagon-like peptide-1 (GLP-1) linked to yohimbine (GLP-1/Yhb) was evaluated to determine its utility as a noninvasive imaging agent. PROCEDURES Competition binding assays were performed on βTC3 cells and isolated rat islets. Immunostaining for insulin was used to co-localized intravenously injected Cy5-labeled GLP-1/Yhb in β cells of Sprague-Dawley rats. Rats were intravenously injected with In-111-labeled GLP-1/Yhb to determine clearance rates and tissue biodistribution. Tissue-specific binding was confirmed by competition with pre-administration of unlabeled GLP-1/Yhb and in Streptozotocin-induced diabetic rats. RESULTS In βTC3 cells, high affinity binding of GLP-1/Yhb required interactions with both receptors because monovalent competition or receptor knockdown with RNAi lowered specificity and avidity of the heterobivalent ligand. Binding specificity for isolated islets was 2.6-fold greater than that of acinar tissue or islets pre-incubated with excess unlabeled GLP-1/Yhb. Immunofluorescent localization of Cy5-labeled GLP-1/Yhb was restricted to pancreatic islets. Within 30 min, ~90% of the In-111-labeled GLP-1/Yhb was cleared from blood. Tissue-specific accumulation of radiolabeled ligand was apparent in the pancreas, but not in other tissues within the abdominal imaging field. Pancreas specificity was lost in Streptozotocin-induced diabetic rats. CONCLUSIONS The GLP-1/Yhb exhibits high specificity for β cells, rapid blood clearance rates, and low non-specific uptake by other tissues within the abdominal imaging field. These characteristics of GLP-1/Yhb are desirable for application to β cell imaging in vivo and provide a basis for developing additional multivalent β cell-specific targeting agents to aid in the management of type 1 diabetes.
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Affiliation(s)
- Leah V Steyn
- School of Animal and Comparative Biomedical Sciences, William J. Parker Agricultural Research Center, The University of Arizona, 4101 N Campbell Ave, Tucson, AZ, 85719, USA
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