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White MR, Yates DT. Dousing the flame: reviewing the mechanisms of inflammatory programming during stress-induced intrauterine growth restriction and the potential for ω-3 polyunsaturated fatty acid intervention. Front Physiol 2023; 14:1250134. [PMID: 37727657 PMCID: PMC10505810 DOI: 10.3389/fphys.2023.1250134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 08/14/2023] [Indexed: 09/21/2023] Open
Abstract
Intrauterine growth restriction (IUGR) arises when maternal stressors coincide with peak placental development, leading to placental insufficiency. When the expanding nutrient demands of the growing fetus subsequently exceed the capacity of the stunted placenta, fetal hypoxemia and hypoglycemia result. Poor fetal nutrient status stimulates greater release of inflammatory cytokines and catecholamines, which in turn lead to thrifty growth and metabolic programming that benefits fetal survival but is maladaptive after birth. Specifically, some IUGR fetal tissues develop enriched expression of inflammatory cytokine receptors and other signaling cascade components, which increases inflammatory sensitivity even when circulating inflammatory cytokines are no longer elevated after birth. Recent evidence indicates that greater inflammatory tone contributes to deficits in skeletal muscle growth and metabolism that are characteristic of IUGR offspring. These deficits underlie the metabolic dysfunction that markedly increases risk for metabolic diseases in IUGR-born individuals. The same programming mechanisms yield reduced metabolic efficiency, poor body composition, and inferior carcass quality in IUGR-born livestock. The ω-3 polyunsaturated fatty acids (PUFA) are diet-derived nutraceuticals with anti-inflammatory effects that have been used to improve conditions of chronic systemic inflammation, including intrauterine stress. In this review, we highlight the role of sustained systemic inflammation in the development of IUGR pathologies. We then discuss the potential for ω-3 PUFA supplementation to improve inflammation-mediated growth and metabolic deficits in IUGR offspring, along with potential barriers that must be considered when developing a supplementation strategy.
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Affiliation(s)
| | - Dustin T. Yates
- Stress Physiology Laboratory, Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE, United States
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2
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Swanson R, Contreras-Correa Z, Dinh T, King H, Sidelinger D, Burnett D, Lemley C. Melatonin Supplementation Alters Maternal and Fetal Amino Acid Concentrations and Placental Nutrient Transporters in a Nutrient Restriction Bovine Model. Metabolites 2022; 12:metabo12121208. [PMID: 36557248 PMCID: PMC9782144 DOI: 10.3390/metabo12121208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/28/2022] [Accepted: 11/30/2022] [Indexed: 12/03/2022] Open
Abstract
Melatonin rescues uterine blood flow and fetal body weight in a seasonal dependent manner within a nutrient restriction bovine model. We sought to identify the effects of nutrient restriction, melatonin, and sampling time on maternal and fetal amino acids, and placental nutrient transporters. Pregnant heifers received adequate or restricted nutrition, and 20 mg of melatonin or placebo from gestational days 160-240 over two seasons. On day 240 maternal and fetal blood, amnion, and placentomes were collected. Amino acid concentrations were determined by gas chromatography-mass spectrometry. Caruncle and cotyledon tissues were assessed for nutrient transporter density by qPCR. Data were analyzed using the MIXED procedure of SAS for fixed effects. In fall, melatonin rescued effects of nutrient restriction on System N, Anion, and total maternal amino acids. Furthermore, melatonin rescued effects of nutrient restriction on Systems A, N, Br, Bo, and essential amnion amino acids. In summer, melatonin rescued effects of nutrient restriction in Systems Br and Bo maternal amino acids. Furthermore, melatonin rescued effects of nutrient restriction on caruncle SLC38A10 and SLC38A2. Melatonin rescued effects of nutrient restriction in a seasonal dependent manner. These data align with previous studies suggesting melatonin is a more effective therapeutic in summer months.
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Affiliation(s)
- Rebecca Swanson
- Department of Animal and Dairy Sciences, Mississippi State University, Starkville, MS 39762, USA
| | - Zully Contreras-Correa
- Department of Animal and Dairy Sciences, Mississippi State University, Starkville, MS 39762, USA
| | - Thu Dinh
- Department of Animal and Dairy Sciences, Mississippi State University, Starkville, MS 39762, USA
| | - Heath King
- College of Veterinary Medicine, Mississippi State University, Starkville, MS 39762, USA
| | - Darcie Sidelinger
- College of Veterinary Medicine, Mississippi State University, Starkville, MS 39762, USA
| | - Derris Burnett
- Department of Animal and Dairy Sciences, Mississippi State University, Starkville, MS 39762, USA
| | - Caleb Lemley
- Department of Animal and Dairy Sciences, Mississippi State University, Starkville, MS 39762, USA
- Correspondence: ; Tel.: +1-662-325-2934
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3
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Valenzuela I, Kinoshita M, van der Merwe J, Maršál K, Deprest J. Prenatal interventions for fetal growth restriction in animal models: A systematic review. Placenta 2022; 126:90-113. [PMID: 35796064 DOI: 10.1016/j.placenta.2022.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 05/20/2022] [Accepted: 06/17/2022] [Indexed: 12/09/2022]
Abstract
Fetal growth restriction (FGR) in human pregnancy is associated with perinatal mortality, short- and long-term morbidities. No prenatal therapy is currently established despite decades of research. We aimed to review interventions in animal models for prenatal FGR treatment, and to seek the next steps for an effective clinical therapy. We registered our protocol and searched MEDLINE, Embase, and The Cochrane Library with no language restrictions, in accordance with the PRISMA guideline. We included all studies that reported the effects of any prenatal intervention in animal models of induced FGR. From 3257 screened studies, 202 describing 237 interventions were included for the final synthesis. Mice and rats were the most used animals (79%) followed by sheep (16%). Antioxidants (23%), followed by vasodilators (18%), nutrients (14%), and immunomodulators (12%) were the most tested therapy. Two-thirds of studies only reported delivery or immediate neonatal outcomes. Adverse effects were rarely reported (11%). Most studies (73%), independent of the intervention, showed a benefit in fetal survival or birthweight. The risk of bias was high, mostly due to the lack of randomization, allocation concealment, and blinding. Future research should aim to describe both short- and long-term outcomes across various organ systems in well-characterized models. Further efforts must be made to reduce selection, performance, and detection bias.
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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] [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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Gibbs RL, Yates DT. The Price of Surviving on Adrenaline: Developmental Programming Responses to Chronic Fetal Hypercatecholaminemia Contribute to Poor Muscle Growth Capacity and Metabolic Dysfunction in IUGR-Born Offspring. FRONTIERS IN ANIMAL SCIENCE 2021; 2:769334. [PMID: 34966907 PMCID: PMC8713512 DOI: 10.3389/fanim.2021.769334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Maternofetal stress induces fetal programming that restricts skeletal muscle growth capacity and metabolic function, resulting in intrauterine growth restriction (IUGR) of the fetus. This thrifty phenotype aids fetal survival but also yields reduced muscle mass and metabolic dysfunction after birth. Consequently, IUGR-born individuals are at greater lifelong risk for metabolic disorders that reduce quality of life. In livestock, IUGR-born animals exhibit poor growth efficiency and body composition, making these animals more costly and less valuable. Specifically, IUGR-associated programming causes a greater propensity for fat deposition and a reduced capacity for muscle accretion. This, combined with metabolic inefficiency, means that these animals produce less lean meat from greater feed input, require more time on feed to reach market weight, and produce carcasses that are of less quality. Despite the health and economic implications of IUGR pathologies in humans and food animals, knowledge regarding their specific underlying mechanisms is lacking. However, recent data indicate that adaptive programing of adrenergic sensitivity in multiple tissues is a contributing factor in a number of IUGR pathologies including reduced muscle mass, peripheral insulin resistance, and impaired glucose metabolism. This review highlights the findings that support the role for adrenergic programming and how it relates to the lifelong consequences of IUGR, as well as how dysfunctional adrenergic signaling pathways might be effective targets for improving outcomes in IUGR-born offspring.
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Affiliation(s)
- Rachel L. Gibbs
- Stress Physiology Laboratory, Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Dustin T. Yates
- Stress Physiology Laboratory, Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE, United States
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Hicks ZM, Yates DT. Going Up Inflame: Reviewing the Underexplored Role of Inflammatory Programming in Stress-Induced Intrauterine Growth Restricted Livestock. FRONTIERS IN ANIMAL SCIENCE 2021; 2. [PMID: 34825243 PMCID: PMC8612632 DOI: 10.3389/fanim.2021.761421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The impact of intrauterine growth restriction (IUGR) on health in humans is well-recognized. It is the second leading cause of perinatal mortality worldwide, and it is associated with deficits in metabolism and muscle growth that increase lifelong risk for hypertension, obesity, hyperlipidemia, and type 2 diabetes. Comparatively, the barrier that IUGR imposes on livestock production is less recognized by the industry. Meat animals born with low birthweight due to IUGR are beset with greater early death loss, inefficient growth, and reduced carcass merit. These animals exhibit poor feed-to-gain ratios, less lean mass, and greater fat deposition, which increase production costs and decrease value. Ultimately, this reduces the amount of meat produced by each animal and threatens the economic sustainability of livestock industries. Intrauterine growth restriction is most commonly the result of fetal programming responses to placental insufficiency, but the exact mechanisms by which this occurs are not well-understood. In uncompromised pregnancies, inflammatory cytokines are produced at modest rates by placental and fetal tissues and play an important role in fetal development. However, unfavorable intrauterine conditions can cause cytokine activity to be excessive during critical windows of fetal development. Our recent evidence indicates that this impacts developmental programming of muscle growth and metabolism and contributes to the IUGR phenotype. In this review, we outline the role of inflammatory cytokine activity in the development of normal and IUGR phenotypes. We also highlight the contributions of sheep and other animal models in identifying mechanisms for IUGR pathologies.
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Affiliation(s)
- Zena M Hicks
- Stress Physiology Laboratory, Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Dustin T Yates
- Stress Physiology Laboratory, Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE, United States
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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 2021; 29:1776-1789. [PMID: 34611848 DOI: 10.1007/s43032-021-00750-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [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.
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Cilvik SN, Wesolowski SR, Anthony RV, Brown LD, Rozance PJ. Late gestation fetal hyperglucagonaemia impairs placental function and results in diminished fetal protein accretion and decreased fetal growth. J Physiol 2021; 599:3403-3427. [PMID: 33878802 DOI: 10.1113/jp281288] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 04/06/2021] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Fetal glucagon concentrations are elevated in the setting of placental insufficiency, hypoxia and elevated stress hormones. Chronically elevated glucagon concentrations in the adult result in profound decreases in amino acid concentrations and lean body mass. Experimental elevation of fetal glucagon concentrations in a late-gestation pregnant sheep results in lower fetal amino acid concentrations, lower protein accretion and lower fetal weight, in addition to decreased placental function. This study demonstrates a negative effect of glucagon on fetal protein accretion and growth, and also provides the first example of a fetal hormone that negatively regulates placental nutrient transport and blood flow. ABSTRACT Fetal glucagon concentrations are elevated in the setting of placental insufficiency and fetal stress. Postnatal studies have demonstrated the importance of glucagon in amino acid metabolism, and limited fetal studies have suggested that glucagon inhibits umbilical uptake of certain amino acids. We hypothesized that chronic fetal hyperglucagonaemia would decrease amino acid transfer and increase amino acid oxidation by the fetus. Late gestation singleton fetal sheep received a direct intravenous infusion of glucagon (GCG; 5 or 50 ng/kg/min; n = 7 and 5, respectively) or a vehicle control (n = 10) for 8-10 days. Fetal and maternal nutrient concentrations, uterine and umbilical blood flows, fetal leucine flux, nutrient uptake rates, placental secretion of chorionic somatomammotropin (CSH), and targeted placental gene expression were measured. GCG fetuses had 13% lower fetal weight compared to controls (P = 0.0239) and >28% lower concentrations of 16 out of 21 amino acids (P < 0.02). Additionally, protein synthesis was 49% lower (P = 0.0005), and protein accretion was 92% lower in GCG fetuses (P = 0.0006). Uterine blood flow was 33% lower in ewes with GCG fetuses (P = 0.0154), while umbilical blood flow was similar. Fetal hyperglucagonaemia lowered uterine uptake of 10 amino acids by >48% (P < 0.05) and umbilical uptake of seven amino acids by >29% (P < 0.04). Placental secretion of CSH into maternal circulation was reduced by 80% compared to controls (P = 0.0080). This study demonstrates a negative effect of glucagon on fetal protein accretion and growth. It also demonstrates that glucagon, a hormone of fetal origin, negatively regulates maternal placental nutrient transport function, placental CSH production and uterine blood flow.
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Affiliation(s)
- Sarah N Cilvik
- Wake Forest University Health Sciences, Winston-Salem, NC, 27157, USA
| | | | - Russ V Anthony
- Colorado State University College of Veterinary Medicine, Fort Collins, CO, USA
| | - Laura D Brown
- University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Paul J Rozance
- University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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Stremming J, Heard S, White A, Chang EI, Shaw SC, Wesolowski SR, Jonker SS, Rozance PJ, Brown LD. IGF-1 infusion to fetal sheep increases organ growth but not by stimulating nutrient transfer to the fetus. Am J Physiol Endocrinol Metab 2021; 320:E527-E538. [PMID: 33427051 PMCID: PMC7988781 DOI: 10.1152/ajpendo.00453.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Insulin-like growth factor-1 (IGF-1) is an important fetal growth factor. However, the role of fetal IGF-1 in increasing placental blood flow, nutrient transfer, and nutrient availability to support fetal growth and protein accretion is not well understood. Catheterized fetuses from late gestation pregnant sheep received an intravenous infusion of LR3 IGF-1 (LR3 IGF-1; n = 8) or saline (SAL; n = 8) for 1 wk. Sheep then underwent a metabolic study to measure uterine and umbilical blood flow, nutrient uptake rates, and fetal protein kinetic rates. By the end of the infusion, fetal weights were not statistically different between groups (SAL: 3.260 ± 0.211 kg, LR3 IGF-1: 3.682 ± 0.183; P = 0.15). Fetal heart, adrenal gland, and spleen weights were higher (P < 0.05), and insulin was lower in LR3 IGF-1 (P < 0.05). Uterine and umbilical blood flow and umbilical uptake rates of glucose, lactate, and oxygen were similar between groups. Umbilical amino acid uptake rates were lower in LR3 IGF-1 (P < 0.05) as were fetal concentrations of multiple amino acids. Fetal protein kinetic rates were similar. LR3 IGF-1 skeletal muscle had higher myoblast proliferation (P < 0.05). In summary, LR3 IGF-1 infusion for 1 wk into late gestation fetal sheep increased the weight of some fetal organs. However, because umbilical amino acid uptake rates and fetal plasma amino acid concentrations were lower in the LR3 IGF-1 group, we speculate that animals treated with LR3 IGF-1 can efficiently utilize available nutrients to support organ-specific growth in the fetus rather than by stimulating placental blood flow or nutrient transfer to the fetus.NEW & NOTEWORTHY After a 1-wk infusion of LR3 IGF-1, late gestation fetal sheep had lower umbilical uptake rates of amino acids, lower fetal arterial amino acid and insulin concentrations, and lower fetal oxygen content; however, LR-3 IGF-1-treated fetuses were still able to effectively utilize the available nutrients and oxygen to support organ growth and myoblast proliferation.
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Affiliation(s)
- Jane Stremming
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Sara Heard
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Alicia White
- 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
| | - Steven C Shaw
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Stephanie R Wesolowski
- 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
| | - Paul J Rozance
- 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
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Tanner AR, Lynch CS, Ali A, Winger QA, Rozance PJ, Anthony RV. Impact of chorionic somatomammotropin RNA interference on uterine blood flow and placental glucose uptake in the absence of intrauterine growth restriction. Am J Physiol Regul Integr Comp Physiol 2021; 320:R138-R148. [PMID: 33146554 PMCID: PMC7948125 DOI: 10.1152/ajpregu.00223.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Chorionic somatomammotropin (CSH) is one of the most abundantly produced placental hormones, yet its exact function remains elusive. Near-term [135 days of gestational age (dGA)], CSH RNA interference (RNAi) results in two distinct phenotypes: 1) pregnancies with intrauterine growth restriction (IUGR), and 2) pregnancies with normal fetal and placental weights. Here, we report the physiological changes in CSH RNAi pregnancies without IUGR. The trophectoderm of hatched blastocysts (9 dGA) were infected with lentiviral-constructs expressing either a scrambled control (Control RNAi) or CSH-specific shRNA (CSH RNAi), prior to transfer into synchronized recipient ewes. At 126 dGA, Control RNAi (n = 6) and CSH RNAi (n = 6) pregnancies were fitted with maternal and fetal catheters. Uterine and umbilical blood flows were measured at 132 dGA and nutrient uptakes were calculated by the Fick's principle. Control RNAi and CSH RNAi pregnancies were compared by analysis of variance, and significance was set at P ≤ 0.05. Absolute (mL/min) and relative (mL/min/kg fetus) uterine blood flows were reduced (P ≤ 0.05) in CSH RNAi pregnancies, but umbilical flows were not impacted. The uterine artery-to-vein glucose gradient (mmol/L) was significantly (P ≤ 0.05) increased. The uteroplacental glucose uptake (μmoL/min/kg placenta) was increased (P ≤ 0.05), whereas umbilical glucose uptake (μmoL/min/kg fetus) was reduced. Our results demonstrate that CSH RNAi has significant physiological ramifications, even in the absence of IUGR, and comparing CSH RNAi pregnancies exhibiting both IUGR and non-IUGR phenotypes may help determine the direct effects of CSH and its potential impact on fetal development.
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Affiliation(s)
- Amelia R. Tanner
- 1Animal Reproduction and Biotechnology Laboratory, Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Cameron S. Lynch
- 1Animal Reproduction and Biotechnology Laboratory, Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Asghar Ali
- 1Animal Reproduction and Biotechnology Laboratory, Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Quinton A. Winger
- 1Animal Reproduction and Biotechnology Laboratory, Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Paul J. Rozance
- 2Perinatal Research Center, University of Colorado School of Medicine, Aurora, Colorado
| | - Russell V. Anthony
- 1Animal Reproduction and Biotechnology Laboratory, Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
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11
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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.
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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
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12
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Boehmer BH, Baker PR, Brown LD, Wesolowski SR, Rozance PJ. Leucine acutely potentiates glucose-stimulated insulin secretion in fetal sheep. J Endocrinol 2020; 247:115-126. [PMID: 32756000 PMCID: PMC7484215 DOI: 10.1530/joe-20-0243] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 08/04/2020] [Indexed: 12/28/2022]
Abstract
A 9-day infusion of leucine into fetal sheep potentiates fetal glucose-stimulated insulin secretion (GSIS). However, there were accompanying pancreatic structural changes that included a larger proportion of β-cells and increased vascularity. Whether leucine can acutely potentiate fetal GSIS in vivo before these structural changes develop is unknown. The mechanisms by which leucine acutely potentiates GSIS in adult islets and insulin-secreting cell lines are well known. These mechanisms involve leucine metabolism, including leucine oxidation. However, it is not clear if leucine-stimulated metabolic pathways are active in fetal islets. We hypothesized that leucine would acutely potentiate GSIS in fetal sheep and that isolated fetal islets are capable of oxidizing leucine. We also hypothesized that leucine would stimulate other metabolic pathways associated with insulin secretion. In pregnant sheep we tested in vivo GSIS with and without an acute leucine infusion. In isolated fetal sheep islets, we measured leucine oxidation with a [1-14C] l-leucine tracer. We also measured concentrations of other amino acids, glucose, and analytes associated with cellular metabolism following incubation of fetal islets with leucine. In vivo, a leucine infusion resulted in glucose-stimulated insulin concentrations that were over 50% higher than controls (P < 0.05). Isolated fetal islets oxidized leucine. Leucine supplementation of isolated fetal islets also resulted in significant activation of metabolic pathways involving leucine and other amino acids. In summary, acute leucine supplementation potentiates fetal GSIS in vivo, likely through pathways related to the oxidation of leucine and catabolism of other amino acids.
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Affiliation(s)
- Brit H. Boehmer
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
| | - Peter R. Baker
- 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
| | - Stephanie R. Wesolowski
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
| | - Paul J. Rozance
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
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13
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Stremming J, Jansson T, Powell TL, Rozance PJ, Brown LD. Reduced Na + K + -ATPase activity may reduce amino acid uptake in intrauterine growth restricted fetal sheep muscle despite unchanged ex vivo amino acid transporter activity. J Physiol 2020; 598:1625-1639. [PMID: 31909825 DOI: 10.1113/jp278933] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 12/02/2019] [Indexed: 12/18/2022] Open
Abstract
KEY POINTS Fetuses with intrauterine growth restriction (IUGR) have reduced muscle mass that persists postnatally, which may contribute to their increased risk for adult onset metabolic diseases, such as diabetes and obesity. Amino acid transporter-mediated histidine uptake and system L amino acid transporter activity were similar in sarcolemmal membranes isolated from control and IUGR hindlimb skeletal muscle. Activity of Na+ K+ -ATPase, which is responsible for establishing the sodium gradient necessary for system A and N amino acid transporter function, was significantly reduced in IUGR skeletal muscle sarcolemma compared to control. ATP content was lower in IUGR skeletal muscle. Expression and phosphorylation of proteins in the mechanistic target of rapamycin pathway were similar in control and IUGR skeletal muscle homogenate. Our data suggest that lower Na+ K+ -ATPase activity, which reduces the driving force for active amino acid transport, and lower ATP availability contribute to reduced amino acid uptake and protein synthesis in IUGR fetal skeletal muscle. ABSTRACT Fetuses with intrauterine growth restriction (IUGR) have lower muscle mass that persists postnatally. Using a sheep model of placental insufficiency and IUGR, we have previously demonstrated lower net total uptake of amino acids by the fetal hindlimb and lower skeletal muscle protein synthesis rates. To investigate the mechanisms underlying these changes, we tested the hypothesis that ex vivo amino acid transporter and Na+ K+ -ATPase activity is reduced, and ex vivo ATP levels are lower in hindlimb skeletal muscle of the IUGR fetus. We developed a novel protocol to measure transporter-mediated histidine uptake, system L amino acid transporter activity and Na+ K+ -ATPase activity using sarcolemmal membranes isolated from hindlimb muscle of control (CON, n = 11-12) and IUGR (n = 12) late gestation fetal sheep. We also determined ATP content and the activity of insulin and mechanistic target of rapamycin (mTOR) signalling, which are involved in regulating cellular amino acid uptake and protein synthesis, by measuring the expression and phosphorylation of AKT, 4E-BP1, eIF2α, AMPKα, p70 S6 kinase and rpS6 in muscle homogenates. Transporter-mediated histidine uptake and system L activity were similar in control and IUGR sarcolemma, although ex vivo Na+ K+ -ATPase activity was lower by 64% (P = 0.019) in IUGR sarcolemma. ATP content was lower by 25% (P = 0.007) in IUGR muscle. Insulin, AMPK, and mTOR signalling activity was similar in control and IUGR muscle. We speculate that reduced muscle sarcolemmal Na+ K+ -ATPase activity and lower ATP content diminishes the sodium gradient in vivo, resulting in a reduced driving force for sodium-dependent transporters and subsequently lower muscle amino acid uptake.
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Affiliation(s)
- Jane Stremming
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Thomas Jansson
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Theresa L Powell
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.,Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Paul J Rozance
- 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
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14
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Zhou TE, Zhu T, Rivera JC, Omri S, Tahiri H, Lahaie I, Rouget R, Wirth M, Nattel S, Lodygensky G, Ferbeyre G, Nezhady M, Desjarlais M, Hamel P, Chemtob S. The Inability of the Choroid to Revascularize in Oxygen-Induced Retinopathy Results from Increased p53/miR-Let-7b Activity. THE AMERICAN JOURNAL OF PATHOLOGY 2019; 189:2340-2356. [PMID: 31430465 DOI: 10.1016/j.ajpath.2019.07.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 07/13/2019] [Accepted: 07/26/2019] [Indexed: 12/18/2022]
Abstract
Retinopathy of prematurity (ROP) is characterized by an initial retinal avascularization, followed by pathologic neovascularization. Recently, choroidal thinning has also been detected in children formerly diagnosed with ROP; a similar sustained choroidal thinning is observed in ROP models. But the mechanism underlying the lack of choroidal revascularization remains unclear and was investigated in an oxygen-induced retinopathy (OIR) model. In OIR, evidence of senescence was detected, preceded by oxidative stress in the choroid and the retinal pigment epithelium. This was associated with a global reduction of proangiogenic factors, including insulin-like growth factor 1 receptor (Igf1R). Coincidentally, tumor suppressor p53 was highly expressed in the OIR retinae. Curtailing p53 activity resulted in reversal of senescence, normalization of Igf1r expression, and preservation of choroidal integrity. OIR-induced down-regulation of Igf1r was mediated at least partly by miR-let-7b as i) let-7b expression was augmented throughout and beyond the period of oxygen exposure, ii) let-7b directly targeted Igf1r mRNA, and iii) p53 knock-down blunted let-7b expression, restored Igf1r expression, and elicited choroidal revascularization. Finally, restoration of Igf1r expression rescued choroid thickness. Altogether, this study uncovers a significant mechanism for defective choroidal revascularization in OIR, revealing a new role for p53/let-7b/IGF-1R axis in the retina. Future investigations on this (and connected) pathway could further our understanding of other degenerative choroidopathies, such as geographic atrophy.
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Affiliation(s)
- Tianwei E Zhou
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada; Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Centre, Université de Montréal, Montréal, Québec, Canada.
| | - Tang Zhu
- Department of Pharmacology, Centre Hospitalier Universitaire Sainte-Justine Hospital, Université de Montréal, Montréal, Québec, Canada
| | - José C Rivera
- Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Centre, Université de Montréal, Montréal, Québec, Canada; Department of Pharmacology, Centre Hospitalier Universitaire Sainte-Justine Hospital, Université de Montréal, Montréal, Québec, Canada; Department of Ophthalmology, Centre Hospitalier Universitaire Sainte-Justine Hospital, Université de Montréal, Montréal, Québec, Canada
| | - Samy Omri
- Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Centre, Université de Montréal, Montréal, Québec, Canada
| | - Houda Tahiri
- Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Centre, Université de Montréal, Montréal, Québec, Canada
| | - Isabelle Lahaie
- Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Centre, Université de Montréal, Montréal, Québec, Canada
| | - Raphaël Rouget
- Department of Pharmacology, Centre Hospitalier Universitaire Sainte-Justine Hospital, Université de Montréal, Montréal, Québec, Canada
| | - Maëlle Wirth
- Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Centre, Université de Montréal, Montréal, Québec, Canada
| | - Stanley Nattel
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada; Department of Medicine, Montreal Heart Institute, Université de Montréal, Montréal, Québec, Canada
| | - Gregory Lodygensky
- Department of Pediatrics, Sainte-Justine University Hospital Centre, Université de Montréal, Montréal, Québec, Canada
| | - Gerardo Ferbeyre
- Department of Biochemistry, Université de Montréal, Montréal, Québec, Canada
| | - Mohammad Nezhady
- Department of Pathology and Cell Biology, University of Montréal, Montréal, Québec, Canada
| | - Michel Desjarlais
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada; Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Centre, Université de Montréal, Montréal, Québec, Canada
| | - Patrick Hamel
- Department of Ophthalmology, Centre Hospitalier Universitaire Sainte-Justine Hospital, Université de Montréal, Montréal, Québec, Canada
| | - Sylvain Chemtob
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada; Department of Ophthalmology, Maisonneuve-Rosemont Hospital Research Centre, Université de Montréal, Montréal, Québec, Canada; Department of Pharmacology, Centre Hospitalier Universitaire Sainte-Justine Hospital, Université de Montréal, Montréal, Québec, Canada; Department of Ophthalmology, Centre Hospitalier Universitaire Sainte-Justine Hospital, Université de Montréal, Montréal, Québec, Canada; Department of Pediatrics, Sainte-Justine University Hospital Centre, Université de Montréal, Montréal, Québec, Canada.
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15
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Posont RJ, Yates DT. Postnatal Nutrient Repartitioning due to Adaptive Developmental Programming. Vet Clin North Am Food Anim Pract 2019; 35:277-288. [PMID: 31103181 DOI: 10.1016/j.cvfa.2019.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Fetal stress induces developmental adaptations that result in intrauterine growth restriction (IUGR) and low birthweight. These adaptations reappropriate nutrients to the most essential tissues, which benefits fetal survival. The same adaptations are detrimental to growth efficiency and carcass value in livestock, however, because muscle is disproportionally targeted. IUGR adipocytes, liver tissues, and pancreatic β-cells also exhibit functional adaptations. Identifying mechanisms underlying adaptive changes is fundamental to improving outcomes and value in low birthweight livestock. The article outlines studies that have begun to identify stress-induced fetal adaptations affecting growth, metabolism, and differential nutrient utilization in IUGR-born animals.
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Affiliation(s)
- Robert J Posont
- Department of Animal Science, University of Nebraska-Lincoln, PO Box 830908, Lincoln, NE 68583, USA
| | - Dustin T Yates
- Department of Animal Science, University of Nebraska-Lincoln, PO Box 830908, Lincoln, NE 68583, USA.
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16
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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] [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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