1
|
Liu Y, Li J, Ding C, Tong H, Yan Y, Li S, Li S, Cao Y. Leu promotes C2C12 cell differentiation by regulating the GSK3β/β-catenin signaling pathway through facilitating the interaction between SESN2 and RPN2. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2024; 104:6696-6705. [PMID: 38551359 DOI: 10.1002/jsfa.13496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 03/02/2024] [Accepted: 03/29/2024] [Indexed: 04/25/2024]
Abstract
BACKGROUND Leucine (Leu) is an essential amino acid that facilitates skeletal muscle satellite cell differentiation, yet its mechanism remains underexplored. Sestrin2 (SESN2) serves as a Leu sensor, binding directly to Leu, while ribophorin II (RPN2) acts as a signaling factor in multiple pathways. This study aimed to elucidate Leu's impact on mouse C2C12 cell differentiation and skeletal muscle injury repair by modulating RPN2 expression through SESN2, offering a theoretical foundation for clinical skeletal muscle injury prevention and treatment. RESULTS Leu addition promoted C2C12 cell differentiation compared to the control, enhancing early differentiation via myogenic determinant (MYOD) up-regulation. Sequencing revealed SESN2 binding to and interacting with RPN2. RPN2 overexpression up-regulated MYOD, myogenin and myosin heavy chain 2, concurrently decreased p-GSK3β and increased nuclear β-catenin. Conversely, RPN2 knockdown yielded opposite results. Combining RPN2 knockdown with Leu rescued increased p-GSK3β and decreased nuclear β-catenin compared to Leu absence. Hematoxylin and eosin staining results showed that Leu addition accelerated mouse muscle damage repair, up-regulating Pax7, MYOD and RPN2 in the cytoplasm, and nuclear β-catenin, confirming that the role of Leu in muscle injury repair was consistent with the results for C2C12 cells. CONCLUSION Leu, bound with SESN2, up-regulated RPN2 expression, activated the GSK3β/β-catenin pathway, enhanced C2C12 differentiation and expedited skeletal muscle damage repair. © 2024 Society of Chemical Industry.
Collapse
Affiliation(s)
- Yifan Liu
- Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
- Laboratory of Cell and Development, Department of Life Science, Northeast Agricultural University, Harbin, China
| | - Jinping Li
- Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
- Laboratory of Cell and Development, Department of Life Science, Northeast Agricultural University, Harbin, China
| | - Cong Ding
- Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
- Laboratory of Cell and Development, Department of Life Science, Northeast Agricultural University, Harbin, China
| | - Huili Tong
- Laboratory of Cell and Development, Department of Life Science, Northeast Agricultural University, Harbin, China
| | - Yunqin Yan
- Laboratory of Cell and Development, Department of Life Science, Northeast Agricultural University, Harbin, China
| | - Shuang Li
- Laboratory of Cell and Development, Department of Life Science, Northeast Agricultural University, Harbin, China
| | - Shufeng Li
- Laboratory of Cell and Development, Department of Life Science, Northeast Agricultural University, Harbin, China
| | - Yunkao Cao
- Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
- Laboratory of Cell and Development, Department of Life Science, Northeast Agricultural University, Harbin, China
| |
Collapse
|
2
|
Nolan CJ, Desoye G. Disentangling fetal insulin hypersecretion and insulin resistance. Trends Endocrinol Metab 2024:S1043-2760(24)00091-2. [PMID: 38697899 DOI: 10.1016/j.tem.2024.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Revised: 04/10/2024] [Accepted: 04/10/2024] [Indexed: 05/05/2024]
Abstract
Disentangling which of insulin hypersecretion and insulin resistance is upstream in obesity-related type 2 diabetes (T2D) is challenging. Here, we consider the dynamics of insulin secretion and action in the fetuses of mothers with diabetes. We argue that fetal insulin hypersecretion occurs first, with insulin resistance being an adaptive protective response.
Collapse
Affiliation(s)
- Christopher J Nolan
- School of Medicine and Psychology, College of Health and Medicine, Australian National University, Acton, ACT 2601, Australia; John Curtin School of Medical Research, College of Health and Medicine, Australian National University, Acton, ACT 2601, Australia; Department of Diabetes and Endocrinology, The Canberra Hospital, Yamba Drive, Garran, ACT 2605, Australia.
| | - Gernot Desoye
- Department of Obstetrics and Gynaecology, Medical University of Graz, Auenbruggerplatz 14, 8036 Graz, Austria
| |
Collapse
|
3
|
Rudar M, Suryawan A, Nguyen HV, Chacko SK, Vonderohe C, Stoll B, Burrin DG, Fiorotto ML, Davis TA. Pulsatile Leucine Administration during Continuous Enteral Feeding Enhances Skeletal Muscle Mechanistic Target of Rapamycin Complex 1 Signaling and Protein Synthesis in a Preterm Piglet Model. J Nutr 2024; 154:505-515. [PMID: 38141773 PMCID: PMC10900192 DOI: 10.1016/j.tjnut.2023.12.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 12/25/2023] Open
Abstract
BACKGROUND Continuous feeding does not elicit an optimal anabolic response in skeletal muscle but is required for some preterm infants. We reported previously that intermittent intravenous pulses of leucine (Leu; 800 μmol Leu·kg-1·h-1 every 4 h) to continuously fed pigs born at term promoted mechanistic target of rapamycin complex 1 (mTORC1) activation and protein synthesis in skeletal muscle. OBJECTIVES The aim was to determine the extent to which intravenous Leu pulses activate mTORC1 and enhance protein synthesis in the skeletal muscle of continuously fed pigs born preterm. METHODS Pigs delivered 10 d preterm was advanced to full oral feeding >4 d and then assigned to 1 of the following 4 treatments for 28 h: 1) ALA (continuous feeding; pulsed with 800 μmol alanine·kg-1·h-1 every 4 h; n = 8); 2) L1× (continuous feeding; pulsed with 800 μmol Leu·kg-1·h-1 every 4 h; n = 7); 3) L2× (continuous feeding; pulsed with 1600 μmol Leu·kg-1·h-1 every 4 h; n = 8); and 4) INT (intermittent feeding every 4 h; supplied with 800 μmol alanine·kg-1 per feeding; n = 7). Muscle protein synthesis rates were determined with L-[2H5-ring]Phenylalanine. The activation of insulin, amino acid, and translation initiation signaling pathways were assessed by Western blot. RESULTS Peak plasma Leu concentrations were 134% and 420% greater in the L2× compared to the L1× and ALA groups, respectively (P < 0.01). Protein synthesis was greater in the L2× than in the ALA and L1× groups in both the longissimus dorsi and gastrocnemius muscles (P < 0.05) but not different from the INT group (P > 0.10). Amino acid signaling upstream and translation initiation signaling downstream of mTORC1 largely corresponded to the differences in protein synthesis. CONCLUSIONS Intravenous Leu pulses potentiate mTORC1 activity and protein synthesis in the skeletal muscles of continuously fed preterm pigs, but the amount required is greater than in pigs born at term.
Collapse
Affiliation(s)
- Marko Rudar
- Department of Animal Sciences, Auburn University, Auburn, AL, United States
| | - Agus Suryawan
- Department of Pediatrics, USDA/Agricultural Research Service, Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, United States
| | - Hanh V Nguyen
- Department of Pediatrics, USDA/Agricultural Research Service, Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, United States
| | - Shaji K Chacko
- Department of Pediatrics, USDA/Agricultural Research Service, Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, United States
| | - Caitlin Vonderohe
- Department of Pediatrics, USDA/Agricultural Research Service, Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, United States
| | - Barbara Stoll
- Department of Pediatrics, USDA/Agricultural Research Service, Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, United States
| | - Douglas G Burrin
- Department of Pediatrics, USDA/Agricultural Research Service, Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, United States
| | - Marta L Fiorotto
- Department of Pediatrics, USDA/Agricultural Research Service, Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, United States
| | - Teresa A Davis
- Department of Pediatrics, USDA/Agricultural Research Service, Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, United States.
| |
Collapse
|
4
|
Page L, Younge N, Freemark M. Hormonal Determinants of Growth and Weight Gain in the Human Fetus and Preterm Infant. Nutrients 2023; 15:4041. [PMID: 37764824 PMCID: PMC10537367 DOI: 10.3390/nu15184041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 09/13/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023] Open
Abstract
The factors controlling linear growth and weight gain in the human fetus and newborn infant are poorly understood. We review here the changes in linear growth, weight gain, lean body mass, and fat mass during mid- and late gestation and the early postnatal period in the context of changes in the secretion and action of maternal, placental, fetal, and neonatal hormones, growth factors, and adipocytokines. We assess the effects of hormonal determinants on placental nutrient delivery and the impact of preterm delivery on hormone expression and postnatal growth and metabolic function. We then discuss the effects of various maternal disorders and nutritional and pharmacologic interventions on fetal and perinatal hormone and growth factor production, growth, and fat deposition and consider important unresolved questions in the field.
Collapse
Affiliation(s)
- Laura Page
- Division of Pediatric Endocrinology, Duke University Medical Center, Durham, NC 27710, USA;
| | - Noelle Younge
- Neonatology, Duke University Medical Center, Durham, NC 27710, USA;
| | - Michael Freemark
- Division of Pediatric Endocrinology, Duke University Medical Center, Durham, NC 27710, USA;
- The Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27710, USA
| |
Collapse
|
5
|
White A, Stremming J, Brown LD, Rozance PJ. Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets. J Dev Orig Health Dis 2023; 14:353-361. [PMID: 37114757 PMCID: PMC10205682 DOI: 10.1017/s2040174423000090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Insulin-like growth factor-1 (IGF-1) is a critical fetal growth hormone that has been proposed as a therapy for intrauterine growth restriction. We previously demonstrated that a 1-week IGF-1 LR3 infusion into fetal sheep reduces in vivo and in vitro insulin secretion suggesting an intrinsic islet defect. Our objective herein was to determine whether this intrinsic islet defect was related to chronicity of exposure. We therefore tested the effects of a 90-min IGF-1 LR3 infusion on fetal glucose-stimulated insulin secretion (GSIS) and insulin secretion from isolated fetal islets. We first infused late gestation fetal sheep (n = 10) with either IGF-1 LR3 (IGF-1) or vehicle control (CON) and measured basal insulin secretion and in vivo GSIS utilizing a hyperglycemic clamp. We then isolated fetal islets immediately following a 90-min IGF-1 or CON in vivo infusion and exposed them to glucose or potassium chloride to measure in vitro insulin secretion (IGF-1, n = 6; CON, n = 6). Fetal plasma insulin concentrations decreased with IGF-1 LR3 infusion (P < 0.05), and insulin concentrations during the hyperglycemic clamp were 66% lower with IGF-1 LR3 infusion compared to CON (P < 0.0001). Insulin secretion in isolated fetal islets was not different based on infusion at the time of islet collection. Therefore, we speculate that while acute IGF-1 LR3 infusion may directly suppress insulin secretion, the fetal β-cell in vitro retains the ability to recover GSIS. This may have important implications when considering the long-term effects of treatment modalities for fetal growth restriction.
Collapse
Affiliation(s)
- Alicia White
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Jane Stremming
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Laura D Brown
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Paul J Rozance
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| |
Collapse
|
6
|
Rozance PJ, Boehmer BH, Chang EI, Wesolowski SR, Brown LD. Chronic Fetal Leucine Infusion Increases Rate of Leucine Oxidation but Not of Protein Synthesis in Late Gestation Fetal Sheep. J Nutr 2023; 153:493-504. [PMID: 36894241 PMCID: PMC10196590 DOI: 10.1016/j.tjnut.2022.12.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 11/19/2022] [Accepted: 12/27/2022] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Leucine increases protein synthesis rates in postnatal animals and adults. Whether supplemental leucine has similar effects in the fetus has not been determined. OBJECTIVE To determine the effect of a chronic leucine infusion on whole-body leucine oxidation and protein metabolic rates, muscle mass, and regulators of muscle protein synthesis in late gestation fetal sheep. METHODS Catheterized fetal sheep at ∼126 d of gestation (term = 147 d) received infusions of saline (CON, n = 11) or leucine (LEU; n = 9) adjusted to increase fetal plasma leucine concentrations by 50%-100% for 9 d. Umbilical substrate net uptake rates and protein metabolic rates were determined using a 1-13C leucine tracer. Myofiber myosin heavy chain (MHC) type and area, expression of amino acid transporters, and abundance of protein synthesis regulators were measured in fetal skeletal muscle. Groups were compared using unpaired t tests. RESULTS Plasma leucine concentrations were 75% higher in LEU fetuses compared with CON by the end of the infusion period (P < 0.0001). Umbilical blood flow and uptake rates of most amino acids, lactate, and oxygen were similar between groups. Fetal whole-body leucine oxidation was 90% higher in LEU (P < 0.0005) but protein synthesis and breakdown rates were similar. Fetal and muscle weights and myofiber areas were similar between groups, however, there were fewer MHC type IIa fibers (P < 0.05), greater mRNA expression levels of amino acid transporters (P < 0.01), and a higher abundance of signaling proteins that regulate protein synthesis (P < 0.05) in muscle from LEU fetuses. CONCLUSIONS A direct leucine infusion for 9 d in late gestation fetal sheep does not increase protein synthesis rates but results in higher leucine oxidation rates and fewer glycolytic myofibers. Increasing leucine concentrations in the fetus stimulates its own oxidation but also increases amino acid transporter expression and primes protein synthetic pathways in skeletal muscle.
Collapse
Affiliation(s)
- Paul J Rozance
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
| | - Brit H Boehmer
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
| | - Eileen I Chang
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
| | - Stephanie R Wesolowski
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
| | - Laura D Brown
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA.
| |
Collapse
|
7
|
Brown LD, Palmer C, Teynor L, Boehmer BH, Stremming J, Chang EI, White A, Jones AK, Cilvik SN, Wesolowski SR, Rozance PJ. Fetal Sex Does Not Impact Placental Blood Flow or Placental Amino Acid Transfer in Late Gestation Pregnant Sheep With or Without Placental Insufficiency. Reprod Sci 2022; 29:1776-1789. [PMID: 34611848 PMCID: PMC8980110 DOI: 10.1007/s43032-021-00750-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 09/24/2021] [Indexed: 10/20/2022]
Abstract
Pregnant sheep have been used to model complications of human pregnancies including placental insufficiency and intrauterine growth restriction. Some of the hallmarks of placental insufficiency are slower uterine and umbilical blood flow rates, impaired placental transport of oxygen and amino acids, and lower fetal arterial concentrations of anabolic growth factors. An impact of fetal sex on these outcomes has not been identified in either human or sheep pregnancies. This is likely because most studies measuring these outcomes have used small numbers of subjects or animals. We undertook a secondary analysis of previously published data generated by our laboratory in late-gestation (gestational age of 133 ± 0 days gestational age) control sheep (n = 29 male fetuses; n = 26 female fetuses; n = 3 sex not recorded) and sheep exposed to elevated ambient temperatures to cause experimental placental insufficiency (n = 23 male fetuses; n = 17 female fetuses; n = 1 sex not recorded). The primary goal was to determine how fetal sex modifies the effect of the experimental insult on outcomes related to placental blood flow, amino acid and oxygen transport, and fetal hormones. Of the 112 outcomes measured, we only found an interaction between fetal sex and experimental insult for the uterine uptake rates of isoleucine, phenylalanine, and arginine. Additionally, most outcomes measured did not show a difference based on fetal sex when adjusting for the impact of placental insufficiency. Exceptions included fetal norepinephrine and cortisol concentrations, which were higher in female compared to male fetuses. For the parameters measured in the current analysis, the impact of fetal sex was not widespread.
Collapse
Affiliation(s)
- Laura D Brown
- Perinatal Research Center, Department of Pediatrics, University of Colorado Anschutz Medical Campus, 13243 East 23rd Avenue, Aurora, CO, 80045, USA
| | - Claire Palmer
- Perinatal Research Center, Department of Pediatrics, University of Colorado Anschutz Medical Campus, 13243 East 23rd Avenue, Aurora, CO, 80045, USA
| | - Lucas Teynor
- Perinatal Research Center, Department of Pediatrics, University of Colorado Anschutz Medical Campus, 13243 East 23rd Avenue, Aurora, CO, 80045, USA
| | - Brit H Boehmer
- Perinatal Research Center, Department of Pediatrics, University of Colorado Anschutz Medical Campus, 13243 East 23rd Avenue, Aurora, CO, 80045, USA
| | - Jane Stremming
- Perinatal Research Center, Department of Pediatrics, University of Colorado Anschutz Medical Campus, 13243 East 23rd Avenue, Aurora, CO, 80045, USA
| | - Eileen I Chang
- Perinatal Research Center, Department of Pediatrics, University of Colorado Anschutz Medical Campus, 13243 East 23rd Avenue, Aurora, CO, 80045, USA
| | - Alicia White
- Perinatal Research Center, Department of Pediatrics, University of Colorado Anschutz Medical Campus, 13243 East 23rd Avenue, Aurora, CO, 80045, USA
| | - Amanda K Jones
- Perinatal Research Center, Department of Pediatrics, University of Colorado Anschutz Medical Campus, 13243 East 23rd Avenue, Aurora, CO, 80045, USA
| | - Sarah N Cilvik
- Perinatal Research Center, Department of Pediatrics, University of Colorado Anschutz Medical Campus, 13243 East 23rd Avenue, Aurora, CO, 80045, USA
| | - Stephanie R Wesolowski
- Perinatal Research Center, Department of Pediatrics, University of Colorado Anschutz Medical Campus, 13243 East 23rd Avenue, Aurora, CO, 80045, USA
| | - Paul J Rozance
- Perinatal Research Center, Department of Pediatrics, University of Colorado Anschutz Medical Campus, 13243 East 23rd Avenue, Aurora, CO, 80045, USA.
| |
Collapse
|
8
|
White A, Stremming J, Boehmer BH, Chang EI, Jonker SS, Wesolowski SR, Brown LD, Rozance PJ. Reduced glucose-stimulated insulin secretion following a 1-wk IGF-1 infusion in late gestation fetal sheep is due to an intrinsic islet defect. Am J Physiol Endocrinol Metab 2021; 320:E1138-E1147. [PMID: 33938236 PMCID: PMC8285601 DOI: 10.1152/ajpendo.00623.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Insulin and insulin-like growth factor-1 (IGF-1) are fetal hormones critical to establishing normal fetal growth. Experimentally elevated IGF-1 concentrations during late gestation increase fetal weight but lower fetal plasma insulin concentrations. We therefore hypothesized that infusion of an IGF-1 analog for 1 wk into late gestation fetal sheep would attenuate fetal glucose-stimulated insulin secretion (GSIS) and insulin secretion in islets isolated from these fetuses. Late gestation fetal sheep received infusions with IGF-1 LR3 (IGF-1, n = 8), an analog of IGF-1 with low affinity for the IGF binding proteins and high affinity for the IGF-1 receptor, or vehicle control (CON, n = 9). Fetal GSIS was measured with a hyperglycemic clamp (IGF-1, n = 8; CON, n = 7). Fetal islets were isolated, and insulin secretion was assayed in static incubations (IGF-1, n = 8; CON, n = 7). Plasma insulin and glucose concentrations in IGF-1 fetuses were lower compared with CON (P = 0.0135 and P = 0.0012, respectively). During the GSIS study, IGF-1 fetuses had lower insulin secretion compared with CON (P = 0.0453). In vitro, glucose-stimulated insulin secretion remained lower in islets isolated from IGF-1 fetuses (P = 0.0447). In summary, IGF-1 LR3 infusion for 1 wk into fetal sheep lowers insulin concentrations and reduces fetal GSIS. Impaired insulin secretion persists in isolated fetal islets indicating an intrinsic islet defect in insulin release when exposed to IGF-1 LR3 infusion for 1 wk. We speculate this alteration in the insulin/IGF-1 axis contributes to the long-term reduction in β-cell function in neonates born with elevated IGF-1 concentrations following pregnancies complicated by diabetes or other conditions associated with fetal overgrowth.NEW & NOTEWORTHY After a 1-wk infusion of IGF-1 LR3, late gestation fetal sheep had lower plasma insulin and glucose concentrations, reduced fetal glucose-stimulated insulin secretion, and decreased fractional insulin secretion from isolated fetal islets without differences in pancreatic insulin content.
Collapse
Affiliation(s)
- Alicia White
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Jane Stremming
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Brit H Boehmer
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Eileen I Chang
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Sonnet S Jonker
- Knight Cardiovascular Institute, Center for Developmental Health, Oregon Health & Science University, Portland, Oregon
| | - Stephanie R Wesolowski
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Laura D Brown
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Paul J Rozance
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| |
Collapse
|
9
|
Boehmer BH, Wesolowski SR, Brown LD, Rozance PJ. Chronic Fetal Leucine Infusion Does Not Potentiate Glucose-Stimulated Insulin Secretion or Affect Pancreatic Islet Development in Late-Gestation Growth-Restricted Fetal Sheep. J Nutr 2020; 151:312-319. [PMID: 33326574 PMCID: PMC7850025 DOI: 10.1093/jn/nxaa357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/28/2020] [Accepted: 10/15/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Growth-restricted fetuses have attenuated glucose-stimulated insulin secretion (GSIS), smaller pancreatic islets, less pancreatic β-cells, and less pancreatic vascularization compared with normally growing fetuses. Infusion of leucine into normal late-gestation fetal sheep potentiates GSIS, as well as increases pancreatic islet size, the proportion of the pancreas and islet comprising β-cells, and pancreatic and islet vascularity. In addition, leucine stimulates hepatocyte growth factor (HGF ) mRNA expression in islet endothelial cells isolated from normal fetal sheep. OBJECTIVE We hypothesized that a 9-d leucine infusion would potentiate GSIS and increase pancreatic islet size, β-cells, and vascularity in intrauterine fetal growth restriction (IUGR) fetal sheep. We also hypothesized that leucine would stimulate HGF mRNA in islet endothelial cells isolated from IUGR fetal sheep. METHODS Late-gestation Columbia-Rambouillet IUGR fetal sheep (singleton or twin) underwent surgeries to place vascular sampling and infusion catheters. Fetuses were randomly allocated to receive a 9-d leucine infusion to achieve a 50-100% increase in leucine concentrations or a control saline infusion. GSIS was measured and pancreas tissue was processed for histologic analysis. Pancreatic islet endothelial cells were isolated from IUGR fetal sheep and incubated with supplemental leucine. Data were analyzed by mixed-models ANOVA; Student, Mann-Whitney, or a paired t test; or a test of equality of proportions. RESULTS Chronic leucine infusion in IUGR fetuses did not affect GSIS, islet size, the proportion of the pancreas comprising β-cells, or pancreatic or pancreatic islet vascularity. In isolated islet endothelial cells from IUGR fetuses, HGF mRNA expression was not affected by supplemental leucine. CONCLUSIONS IUGR fetal sheep islets are not responsive to a 9-d leucine infusion with respect to insulin secretion or any histologic features measured. This is in contrast to the response in normally growing fetuses. These results are important when considering nutritional strategies to prevent the adverse islet and β-cell consequences in IUGR fetuses.
Collapse
Affiliation(s)
- Brit H Boehmer
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, CO, USA
| | - Stephanie R Wesolowski
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, CO, USA
| | - Laura D Brown
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, CO, USA
| | | |
Collapse
|