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Tanner AR, Kennedy VC, Lynch CS, Winger QA, Anthony RV, Rozance PJ. Increasing maternal glucose concentrations is insufficient to restore placental glucose transfer in chorionic somatomammotropin RNA interference pregnancies. Am J Physiol Endocrinol Metab 2024; 326:E602-E615. [PMID: 38353640 DOI: 10.1152/ajpendo.00331.2023] [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: 10/06/2023] [Revised: 02/01/2024] [Accepted: 02/05/2024] [Indexed: 04/19/2024]
Abstract
We previously demonstrated impaired placental nutrient transfer in chorionic somatomammotropin (CSH) RNA interference (RNAi) pregnancies, with glucose transfer being the most impacted. Thus, we hypothesized that despite experimentally elevating maternal glucose, diminished umbilical glucose uptake would persist in CSH RNAi pregnancies, demonstrating the necessity of CSH for adequate placental glucose transfer. Trophectoderm of sheep blastocysts (9 days of gestational age; dGA) were infected with a lentivirus expressing either nontargeting control (CON RNAi; n = 5) or CSH-specific shRNA (CSH RNAi; n = 7) before transfer into recipient sheep. At 126 dGA, pregnancies were fitted with vascular catheters and underwent steady-state metabolic studies (3H2O transplacental diffusion) at 137 ± 0 dGA, before and during a maternal hyperglycemic clamp. Umbilical glucose and oxygen uptakes, as well as insulin and IGF1 concentrations, were impaired (P ≤ 0.01) in CSH RNAi fetuses and were not rescued by elevated maternal glucose. This is partially due to impaired uterine and umbilical blood flow (P ≤ 0.01). However, uteroplacental oxygen utilization was greater (P ≤ 0.05) during the maternal hyperglycemic clamp, consistent with greater placental oxidation of substrates. The relationship between umbilical glucose uptake and the maternal-fetal glucose gradient was analyzed, and while the slope (CON RNAi, Y = 29.54X +74.15; CSH RNAi, Y = 19.05X + 52.40) was not different, the y-intercepts and elevation were (P = 0.003), indicating reduced maximal glucose transport during maternal hyperglycemia. Together, these data suggested that CSH plays a key role in modulating placental metabolism that ultimately promotes maximal placental glucose transfer.NEW & NOTEWORTHY The current study demonstrated a novel, critical autocrine role for chorionic somatomammotropin in augmenting placental glucose transfer and maintaining placental oxidative metabolism. In pregnancies with CSH deficiency, excess glucose in maternal circulation is insufficient to overcome fetal hypoglycemia due to impaired placental glucose transfer and elevated placental metabolic demands. This suggests that perturbations in glucose transfer in CSH RNAi pregnancies are due to compromised metabolic efficiency along with reduced placental mass.
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Affiliation(s)
- Amelia R Tanner
- Animal Reproduction and Biotechnology Laboratory, Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States
- Perinatal Research Center, University of Colorado School of Medicine, Aurora, Colorado, United States
| | - Victoria C Kennedy
- Animal Reproduction and Biotechnology Laboratory, Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States
| | - Cameron S Lynch
- Animal Reproduction and Biotechnology Laboratory, Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States
| | - Quinton A Winger
- Animal Reproduction and Biotechnology Laboratory, Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States
| | - Russell V Anthony
- Animal Reproduction and Biotechnology Laboratory, Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States
| | - Paul J Rozance
- Perinatal Research Center, University of Colorado School of Medicine, Aurora, Colorado, United States
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Brown LD, Rozance PJ, Wang D, Eroglu EC, Wilkening RB, Solmonson A, Wesolowski SR. Increased hepatic glucose production with lower oxidative metabolism in the growth-restricted fetus. JCI Insight 2024; 9:e176497. [PMID: 38687612 DOI: 10.1172/jci.insight.176497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 04/17/2024] [Indexed: 05/02/2024] Open
Abstract
Fetal growth restriction (FGR) is accompanied by early activation of hepatic glucose production (HGP), a hallmark of type 2 diabetes (T2D). Here, we used fetal hepatic catheterization to directly measure HGP and substrate flux in a sheep FGR model. We hypothesized that FGR fetuses would have increased hepatic lactate and amino acid uptake to support increased HGP. Indeed, FGR fetuses compared with normal (CON) fetuses had increased HGP and activation of gluconeogenic genes. Unexpectedly, hepatic pyruvate output was increased, while hepatic lactate and gluconeogenic amino acid uptake rates were decreased in FGR liver. Hepatic oxygen consumption and total substrate uptake rates were lower. In FGR liver tissue, metabolite abundance, 13C-metabolite labeling, enzymatic activity, and gene expression supported decreased pyruvate oxidation and increased lactate production. Isolated hepatocytes from FGR fetuses had greater intrinsic capacity for lactate-fueled glucose production. FGR livers also had lower energy (ATP) and redox state (NADH/NAD+ ratio). Thus, reduced hepatic oxidative metabolism may make carbons available for increased HGP, but also produces nutrient and energetic stress in FGR liver. Intrinsic programming of these pathways regulating HGP in the FGR fetus may underlie increased HGP and T2D risk postnatally.
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Affiliation(s)
- Laura D Brown
- Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Paul J Rozance
- Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Dong Wang
- Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Evren C Eroglu
- Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Randall B Wilkening
- Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Ashley Solmonson
- University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Stephanie R Wesolowski
- Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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3
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Swenson KS, Wang D, Jones AK, Nash MJ, O’Rourke R, Takahashi DL, Kievit P, Hennebold JD, Aagaard KM, Friedman JE, Jones KL, Rozance PJ, Brown LD, Wesolowski SR. Metformin Disrupts Signaling and Metabolism in Fetal Hepatocytes. Diabetes 2023; 72:1214-1227. [PMID: 37347736 PMCID: PMC10450827 DOI: 10.2337/db23-0089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 06/20/2023] [Indexed: 06/24/2023]
Abstract
Metformin is used by women during pregnancy to manage diabetes and crosses the placenta, yet its effects on the fetus are unclear. We show that the liver is a site of metformin action in fetal sheep and macaques, given relatively abundant OCT1 transporter expression and hepatic uptake following metformin infusion into fetal sheep. To determine the effects of metformin action, we performed studies in primary hepatocytes from fetal sheep, fetal macaques, and juvenile macaques. Metformin increases AMP-activated protein kinase (AMPK) signaling, decreases mammalian target of rapamycin (mTOR) signaling, and decreases glucose production in fetal and juvenile hepatocytes. Metformin also decreases oxygen consumption in fetal hepatocytes. Unique to fetal hepatocytes, metformin activates stress pathways (e.g., increased PGC1A gene expression, NRF-2 protein abundance, and phosphorylation of eIF2α and CREB proteins) alongside perturbations in hepatokine expression (e.g., increased growth/differentiation factor 15 [GDF15] and fibroblast growth factor 21 [FGF21] expression and decreased insulin-like growth factor 2 [IGF2] expression). Similarly, in liver tissue from sheep fetuses infused with metformin in vivo, AMPK phosphorylation, NRF-2 protein, and PGC1A expression are increased. These results demonstrate disruption of signaling and metabolism, induction of stress, and alterations in hepatokine expression in association with metformin exposure in fetal hepatocytes. ARTICLE HIGHLIGHTS The major metformin uptake transporter OCT1 is expressed in the fetal liver, and fetal hepatic uptake of metformin is observed in vivo. Metformin activates AMPK, reduces glucose production, and decreases oxygen consumption in fetal hepatocytes, demonstrating similar effects as in juvenile hepatocytes. Unique to fetal hepatocytes, metformin activates metabolic stress pathways and alters the expression of secreted growth factors and hepatokines. Disruption of signaling and metabolism with increased stress pathways and reduced anabolic pathways by metformin in the fetal liver may underlie reduced growth in fetuses exposed to metformin.
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Affiliation(s)
- Karli S. Swenson
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO
| | - Dong Wang
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO
| | - Amanda K. Jones
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO
| | - Michael J. Nash
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO
| | - Rebecca O’Rourke
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO
| | - Diana L. Takahashi
- Division of Cardiometabolic Health, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR
| | - Paul Kievit
- Division of Cardiometabolic Health, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR
| | - Jon D. Hennebold
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR
| | - Kjersti M. Aagaard
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Baylor College of Medicine & Texas Children’s Hospital, Houston, TX
| | - Jacob E. Friedman
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Kenneth L. Jones
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Paul J. Rozance
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO
| | - Laura D. Brown
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO
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4
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Kyllo HM, Wang D, Lorca RA, Julian CG, Moore LG, Wilkening RB, Rozance PJ, Brown LD, Wesolowski SR. Adaptive responses in uteroplacental metabolism and fetoplacental nutrient shuttling and sensing during placental insufficiency. Am J Physiol Endocrinol Metab 2023; 324:E556-E568. [PMID: 37126847 PMCID: PMC10259853 DOI: 10.1152/ajpendo.00046.2023] [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: 02/13/2023] [Revised: 04/12/2023] [Accepted: 04/25/2023] [Indexed: 05/03/2023]
Abstract
Glucose, lactate, and amino acids are major fetal nutrients. During placental insufficiency-induced intrauterine growth restriction (PI-IUGR), uteroplacental weight-specific oxygen consumption rates are maintained, yet fetal glucose and amino acid supply is decreased and fetal lactate concentrations are increased. We hypothesized that uteroplacental metabolism adapts to PI-IUGR by altering nutrient allocation to maintain oxidative metabolism. Here, we measured nutrient flux rates, with a focus on nutrients shuttled between the placenta and fetus (lactate-pyruvate, glutamine-glutamate, and glycine-serine) in a sheep model of PI-IUGR. PI-IUGR fetuses weighed 40% less and had decreased oxygen, glucose, and amino acid concentrations and increased lactate and pyruvate versus control (CON) fetuses. Uteroplacental weight-specific rates of oxygen, glucose, lactate, and pyruvate uptake were similar. In PI-IUGR, fetal glucose uptake was decreased and pyruvate output was increased. In PI-IUGR placental tissue, pyruvate dehydrogenase (PDH) phosphorylation was decreased and PDH activity was increased. Uteroplacental glutamine output to the fetus and expression of genes regulating glutamine-glutamate metabolism were lower in PI-IUGR. Fetal glycine uptake was lower in PI-IUGR, with no differences in uteroplacental glycine or serine flux. These results suggest increased placental utilization of pyruvate from the fetus, without higher maternal glucose utilization, and lower fetoplacental amino acid shuttling during PI-IUGR. Mechanistically, AMP-activated protein kinase (AMPK) activation was higher and associated with thiobarbituric acid-reactive substances (TBARS) content, a marker of oxidative stress, and PDH activity in the PI-IUGR placenta, supporting a potential link between oxidative stress, AMPK, and pyruvate utilization. These differences in fetoplacental nutrient sensing and shuttling may represent adaptive strategies enabling the placenta to maintain oxidative metabolism.NEW & NOTEWORTHY These results suggest increased placental utilization of pyruvate from the fetus, without higher maternal glucose uptake, and lower amino acid shuttling in the placental insufficiency-induced intrauterine growth restriction (PI-IUGR) placenta. AMPK activation was associated with oxidative stress and PDH activity, supporting a putative link between oxidative stress, AMPK, and pyruvate utilization. These differences in fetoplacental nutrient sensing and shuttling may represent adaptive strategies enabling the placenta to maintain oxidative metabolism at the expense of fetal growth.
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Affiliation(s)
- Hannah M Kyllo
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado, United States
| | - Dong Wang
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado, United States
| | - Ramón A Lorca
- Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, Colorado, United States
| | - Colleen G Julian
- Department of Biomedical Informatics, University of Colorado School of Medicine, Aurora, Colorado, United States
| | - Lorna G Moore
- Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, Colorado, United States
| | - Randall B Wilkening
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado, United States
| | - Paul J Rozance
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado, United States
| | - Laura D Brown
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado, United States
| | - Stephanie R Wesolowski
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado, United States
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5
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Wilson RL, Stephens KK, Jones HN. Placental nanoparticle gene therapy normalizes gene expression changes in the fetal liver associated with fetal growth restriction in a fetal sex-specific manner. J Dev Orig Health Dis 2023; 14:325-332. [PMID: 36794386 PMCID: PMC10947591 DOI: 10.1017/s2040174423000016] [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: 02/17/2023]
Abstract
Fetal growth restriction (FGR) is associated with increased risk of developing non-communicable diseases. We have a placenta-specific nanoparticle gene therapy protocol that increases placental expression of human insulin-like growth factor 1 (hIGF1), for the treatment of FGR in utero. We aimed to characterize the effects of FGR on hepatic gluconeogenesis pathways during early stages of FGR establishment, and determine whether placental nanoparticle-mediated hIGF1 therapy treatment could resolve differences in the FGR fetus. Female Hartley guinea pigs (dams) were fed either a Control or Maternal Nutrient Restriction (MNR) diet using established protocols. At GD30-33, dams underwent ultrasound guided, transcutaneous, intraplacental injection of hIGF1 nanoparticle or PBS (sham) and were sacrificed 5 days post-injection. Fetal liver tissue was fixed and snap frozen for morphology and gene expression analysis. In female and male fetuses, liver weight as a percentage of body weight was reduced by MNR, and not changed with hIGF1 nanoparticle treatment. In female fetal livers, expression of hypoxia inducible factor 1 (Hif1α) and tumor necrosis factor (Tnfα) were increased in MNR compared to Control, but reduced in MNR + hIGF1 compared to MNR. In male fetal liver, MNR increased expression of Igf1 and decreased expression of Igf2 compared to Control. Igf1 and Igf2 expression was restored to Control levels in the MNR + hIGF1 group. This data provides further insight into the sex-specific mechanistic adaptations seen in FGR fetuses and demonstrates that disruption to fetal developmental mechanisms may be returned to normal by treatment of the placenta.
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Affiliation(s)
- Rebecca L Wilson
- Center for Research in Perinatal Outcomes, University of Florida College of Medicine, Gainesville, Florida 32610, USA
- Department of Physiology and Aging, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Kendal K Stephens
- Department of Obstetrics and Gynecology, University of Cincinnati, Cincinnati, Ohio, 45229, USA
| | - Helen N Jones
- Center for Research in Perinatal Outcomes, University of Florida College of Medicine, Gainesville, Florida 32610, USA
- Department of Physiology and Aging, University of Florida College of Medicine, Gainesville, Florida 32610, USA
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6
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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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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] [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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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: 1] [Impact Index Per Article: 0.3] [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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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] [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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10
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Tanner AR, Lynch CS, Kennedy VC, Ali A, Winger QA, Rozance PJ, Anthony RV. CSH RNA Interference Reduces Global Nutrient Uptake and Umbilical Blood Flow Resulting in Intrauterine Growth Restriction. Int J Mol Sci 2021; 22:ijms22158150. [PMID: 34360913 PMCID: PMC8348624 DOI: 10.3390/ijms22158150] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/21/2021] [Accepted: 07/27/2021] [Indexed: 01/03/2023] Open
Abstract
Deficiency of the placental hormone chorionic somatomammotropin (CSH) can lead to the development of intrauterine growth restriction (IUGR). To gain insight into the physiological consequences of CSH RNA interference (RNAi), the trophectoderm of hatched blastocysts (nine days of gestational age; dGA) was infected with a lentivirus expressing either a scrambled control or CSH-specific shRNA, prior to transfer into synchronized recipient sheep. At 90 dGA, umbilical hemodynamics and fetal measurements were assessed by Doppler ultrasonography. At 120 dGA, pregnancies were fitted with vascular catheters to undergo steady-state metabolic studies with the 3H2O transplacental diffusion technique at 130 dGA. Nutrient uptake rates were determined and tissues were subsequently harvested at necropsy. CSH RNAi reduced (p ≤ 0.05) both fetal and uterine weights as well as umbilical blood flow (mL/min). This ultimately resulted in reduced (p ≤ 0.01) umbilical IGF1 concentrations, as well as reduced umbilical nutrient uptakes (p ≤ 0.05) in CSH RNAi pregnancies. CSH RNAi also reduced (p ≤ 0.05) uterine nutrient uptakes as well as uteroplacental glucose utilization. These data suggest that CSH is necessary to facilitate adequate blood flow for the uptake of oxygen, oxidative substrates, and hormones essential to support fetal and uterine growth.
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Affiliation(s)
- Amelia R. Tanner
- College of Veterinary Medicine, Colorado State University, Fort Collins, CO 80523, USA; (A.R.T.); (C.S.L.); (V.C.K.); (A.A.); (Q.A.W.)
| | - Cameron S. Lynch
- College of Veterinary Medicine, Colorado State University, Fort Collins, CO 80523, USA; (A.R.T.); (C.S.L.); (V.C.K.); (A.A.); (Q.A.W.)
| | - Victoria C. Kennedy
- College of Veterinary Medicine, Colorado State University, Fort Collins, CO 80523, USA; (A.R.T.); (C.S.L.); (V.C.K.); (A.A.); (Q.A.W.)
| | - Asghar Ali
- College of Veterinary Medicine, Colorado State University, Fort Collins, CO 80523, USA; (A.R.T.); (C.S.L.); (V.C.K.); (A.A.); (Q.A.W.)
| | - Quinton A. Winger
- College of Veterinary Medicine, Colorado State University, Fort Collins, CO 80523, USA; (A.R.T.); (C.S.L.); (V.C.K.); (A.A.); (Q.A.W.)
| | - Paul J. Rozance
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA;
| | - Russell V. Anthony
- College of Veterinary Medicine, Colorado State University, Fort Collins, CO 80523, USA; (A.R.T.); (C.S.L.); (V.C.K.); (A.A.); (Q.A.W.)
- Correspondence:
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11
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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] [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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12
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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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13
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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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14
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Rozance PJ, Jones AK, Bourque SL, D'Alessandro A, Hay WW, Brown LD, Wesolowski SR. Effects of chronic hyperinsulinemia on metabolic pathways and insulin signaling in the fetal liver. Am J Physiol Endocrinol Metab 2020; 319:E721-E733. [PMID: 32830555 PMCID: PMC7864241 DOI: 10.1152/ajpendo.00323.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The effect of chronic of hyperinsulinemia in the fetal liver is poorly understood. Here, we produced hyperinsulinemia with euglycemia for ∼8 days in fetal sheep [hyperinsulinemic (INS)] at 0.9 gestation. INS fetuses had increased insulin and decreased oxygen and amino acid (AA) concentrations compared with saline-infused fetuses [control (CON)]. Glucose (whole body) utilization rates were increased, as expected, in INS fetuses. In the liver, however, there were few differences in genes and metabolites related to glucose and lipid metabolism and no activation of insulin signaling proteins (Akt and mTOR). There was increased p-AMPK activation and decreased mitochondrial mass (PGC1A expression, mitochondrial DNA content) in INS livers. Using an unbiased multivariate analysis with 162 metabolites, we identified effects on AA and one-carbon metabolism in the INS liver. Expression of the transaminase BCAT2 and glutaminase genes GLS1 and GLS2 was decreased, supporting decreased AA utilization. We further evaluated the roles of hyperinsulinemia and hypoxemia, both present in INS fetuses, on outcomes in the liver. Expression of PGC1A correlated only with hyperinsulinemia, p-AMPK correlated only with hypoxemia, and other genes and metabolites correlated with both hyperinsulinemia and hypoxemia. In fetal hepatocytes, acute treatment with insulin activated p-Akt and decreased PGC1A, whereas hypoxia activated p-AMPK. Overall, chronic hyperinsulinemia produced greater effects on amino acid metabolism compared with glucose and lipid metabolism and a novel effect on one-carbon metabolism in the fetal liver. These hepatic metabolic responses may result from the downregulation of insulin signaling and antagonistic effects of hypoxemia-induced AMPK activation that develop with chronic hyperinsulinemia.
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Affiliation(s)
- Paul J Rozance
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Amanda K Jones
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Stephanie L Bourque
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Angelo D'Alessandro
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - William W Hay
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Laura D Brown
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Stephanie R Wesolowski
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
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15
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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] [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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16
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Rood K, Lopez V, La Frano MR, Fiehn O, Zhang L, Blood AB, Wilson SM. Gestational Hypoxia and Programing of Lung Metabolism. Front Physiol 2019; 10:1453. [PMID: 31849704 PMCID: PMC6895135 DOI: 10.3389/fphys.2019.01453] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 11/11/2019] [Indexed: 12/12/2022] Open
Abstract
Gestational hypoxia is a risk factor in the development of pulmonary hypertension in the newborn and other sequela, however, the mechanisms associated with the disease remain poorly understood. This review highlights disruption of metabolism by antenatal high altitude hypoxia and the impact this has on pulmonary hypertension in the newborn with discussion of model organisms and human populations. There is particular emphasis on modifications in glucose and lipid metabolism along with alterations in mitochondrial function. Additional focus is placed on increases in oxidative stress and the progression of pulmonary vascular disease in the newborn and on the need for further exploration using a combination of contemporary and classical approaches.
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Affiliation(s)
- Kristiana Rood
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Vanessa Lopez
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Michael R La Frano
- Department of Food Science and Nutrition, Center for Health Research, California Polytechnic State University, San Luis Obispo, CA, United States.,Center for Health Research, California Polytechnic State University, San Luis Obispo, CA, United States
| | - Oliver Fiehn
- NIH West Coast Metabolomics Center, University of California, Davis, Davis, CA, United States.,Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA, United States
| | - Lubo Zhang
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Arlin B Blood
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Sean M Wilson
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
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