The impact of IUGR on pancreatic islet development and β-cell function

Fetal Hypoglycemia Induced by Placental SLC2A3-RNA Interference Alters Fetal Pancreas Development and Transcriptome at Mid-Gestation

Glucose, the primary energy substrate for fetal oxidative processes and growth, is transferred from maternal to fetal circulation down a concentration gradient by placental facilitative glucose transporters. In sheep, SLC2A1 and SLC2A3 are the primary transporters available in the placental epithelium, with SLC2A3 located on the maternal-facing apical trophoblast membrane and SLC2A1 located on the fetal-facing basolateral trophoblast membrane. We have previously reported that impaired placental SLC2A3 glucose transport resulted in smaller, hypoglycemic fetuses with reduced umbilical artery insulin and glucagon concentrations, in addition to diminished pancreas weights. These findings led us to subject RNA derived from SLC2A3-RNAi (RNA interference) and NTS-RNAi (non-targeting sequence) fetal pancreases to qPCR followed by transcriptomic analysis. We identified a total of 771 differentially expressed genes (DEGs). Upregulated pathways were associated with fat digestion and absorption, particularly fatty acid transport, lipid metabolism, and cholesterol biosynthesis, suggesting a potential switch in energetic substrates due to hypoglycemia. Pathways related to molecular transport and cell signaling in addition to pathways influencing growth and metabolism of the developing pancreas were also impacted. A few genes directly related to gluconeogenesis were also differentially expressed. Our results suggest that fetal hypoglycemia during the first half of gestation impacts fetal pancreas development and function that is not limited to β cell activity.

Paternal DDT exposure induces sex-specific programming of fetal growth, placenta development and offspring's health phenotypes in a mouse model

Mounting evidence suggests that environmentally induced epigenetic inheritance occurs in mammals and that traits in the progeny can be shaped by parental environmental experiences. Epidemiological studies link parental exposure to environmental toxicants, such as the pesticide DDT, to health phenotypes in the progeny, including low birth and increased risk of chronic diseases later in life. Here, we show that the progeny of male mice exposed to DDT in the pre-conception period are born smaller and exhibit sexual dimorphism in metabolic function, with male, but not female, offspring developing severe glucose intolerance compared to controls. These phenotypes in DDT offspring were linked to reduced fetal growth and placenta size as well as placenta-specific reduction of glycogen levels and the nutrient sensor and epigenetic regulator OGT, with more pronounced phenotypes observed in male placentas. However, placenta-specific genetic reduction of OGT only partially replicates the metabolic phenotype observed in offspring of DDT-exposed males. Our findings reveal a role for paternal pre-conception environmental experiences in shaping placenta development and in fetal growth restriction. While many questions remain, our data raise the tantalizing possibility that placenta programming could be a mediator of environmentally induced intergenerational epigenetic inheritance of phenotypes and needs to be further evaluated.

Metabolic and fecal microbial changes in adult fetal growth restricted mice

BACKGROUND

Fetal growth restriction (FGR) increases risk for development of obesity and type 2 diabetes. Using a mouse model of FGR, we tested whether metabolic outcomes were exacerbated by high-fat diet challenge or associated with fecal microbial taxa.

METHODS

FGR was induced by maternal calorie restriction from gestation day 9 to 19. Control and FGR offspring were weaned to control (CON) or 45% fat diet (HFD). At age 16 weeks, offspring underwent intraperitoneal glucose tolerance testing, quantitative MRI body composition assessment, and energy balance studies. Total microbial DNA was used for amplification of the V4 variable region of the 16 S rRNA gene. Multivariable associations between groups and genera abundance were assessed using MaAsLin2.

RESULTS

Adult male FGR mice fed HFD gained weight faster and had impaired glucose tolerance compared to control HFD males, without differences among females. Irrespective of weaning diet, adult FGR males had depletion of Akkermansia, a mucin-residing genus known to be associated with weight gain and glucose handling. FGR females had diminished Bifidobacterium. Metabolic changes in FGR offspring were associated with persistent gut microbial changes.

CONCLUSION

FGR results in persistent gut microbial dysbiosis that may be a therapeutic target to improve metabolic outcomes.

IMPACT

Fetal growth restriction increases risk for metabolic syndrome later in life, especially if followed by rapid postnatal weight gain. We report that a high fat diet impacts weight and glucose handling in a mouse model of fetal growth restriction in a sexually dimorphic manner. Adult growth-restricted offspring had persistent changes in fecal microbial taxa known to be associated with weight, glucose homeostasis, and bile acid metabolism, particularly Akkermansia, Bilophilia and Bifidobacteria. The gut microbiome may represent a therapeutic target to improve long-term metabolic outcomes related to fetal growth restriction.

RISING STARS: Mechanistic insights into maternal-fetal cross talk and islet beta-cell development

The metabolic health trajectory of an individual is shaped as early as prepregnancy, during pregnancy, and lactation period. Both maternal nutrition and metabolic health status are critical factors in the programming of offspring toward an increased propensity to developing type 2 diabetes in adulthood. Pancreatic beta-cells, part of the endocrine islets, which are nutrient-sensitive tissues important for glucose metabolism, are primed early in life (the first 1000 days in humans) with limited plasticity later in life. This suggests the high importance of the developmental window of programming in utero and early in life. This review will focus on how changes to the maternal milieu increase offspring's susceptibility to diabetes through changes in pancreatic beta-cell mass and function and discuss potential mechanisms by which placental-driven nutrient availability, hormones, exosomes, and immune alterations that may impact beta-cell development in utero, thereby affecting susceptibility to type 2 diabetes in adulthood.

The physiological basis with uterine myometrium contractions from electro-mechanical/hormonal myofibril function to the term and preterm labor

Background

Most labor-related problems can be attributed to the uterine myometrium muscle, as this irritable tissue must suppress its irritability potential during pregnancy. Unfortunately, fewer studies have investigated the causes of this lack of suppression in preterm labor.

Methods

We conducted a scoping narrative review using three online databases (PubMed, Scopus, and Science Direct).

Results

The review focused on ion channel functions in the myometrium, including sodium channels [Na K-ATPase, Na-activated K channels (Slo2), voltage-gated (SCN) Na+, Na+ leaky channels, nonselective (NALCN) channels], potassium channels [KATP (Kir6) channels, voltage-dependent K channels (Kv4, Kv7, and Kv11), twin-pore domain K channels (TASK, TREK), inward rectifier Kir7.1, Ca2+-activated K+ channels with large (KCNMA1, Slo1), small (KCNN1-3), intermediate (KCNN4) conductance], and calcium channels [L-Type and T-type Ca2+ channels, calcium-activated chloride channels (CaCC)], as well as hyperpolarization-activated cation channels. These channels' functions are associated with hormonal effects such as oxytocin, estrogen/progesterone, and local prostaglandins.

Conclusion

Electromechanical/hormonal activity and environmental autocrine factors can serve as the primary practical basis for premature uterine contractions in term/preterm labor. Our findings highlight the significance of.1.the amplitude rate of hyperpolarization and the frequency of contractions,2.changes in the estrogen/progesterone ratio,3.Prostaglandins E/F involvement in initiating potential spikes and the increase of intracytoplasmic Ca2+.This narrative study highlights the range of hyperpolarization and the frequency of myometrium contractions as crucial factors. The synchronized complex progress of estrogen to progesterone ratio and prostaglandins plays a significant role in initiating potential spikes and increasing intracytoplasmic Ca2+, which further influences the contraction process during labor. Insights into myometrium physiology gained from this study may pave the way for much-needed new treatments to reduce problems associated with normal and preterm labor.

Maternal-fetal cross-talk via the placenta: influence on offspring development and metabolism

Compelling epidemiological and animal experimental data demonstrate that cardiometabolic and neuropsychiatric diseases originate in a suboptimal intrauterine environment. Here, we review evidence suggesting that altered placental function may, at least in part, mediate the link between the maternal environment and changes in fetal growth and development. Emerging evidence indicates that the placenta controls the development and function of several fetal tissues through nutrient sensing, modulation of trophoblast nutrient transporters and by altering the number and cargo of released extracellular vesicles. In this Review, we discuss the development and functions of the maternal-placental-fetal interface (in humans and mice) and how cross-talk between these compartments may be a mechanism for in utero programming, focusing on mechanistic target of rapamycin (mTOR), adiponectin and O-GlcNac transferase (OGT) signaling. We also discuss how maternal diet and stress influences fetal development and metabolism and how fetal growth restriction can result in susceptibility to developing chronic disease later in life. Finally, we speculate how interventions targeting placental function may offer unprecedented opportunities to prevent cardiometabolic disease in future generations.

Daily injection of the β2 adrenergic agonist clenbuterol improved poor muscle growth and body composition in lambs following heat stress-induced intrauterine growth restriction

Background: Intrauterine growth restriction (IUGR) is associated with reduced β2 adrenergic sensitivity, which contributes to poor postnatal muscle growth. The objective of this study was to determine if stimulating β2 adrenergic activity postnatal would rescue deficits in muscle growth, body composition, and indicators of metabolic homeostasis in IUGR offspring. Methods: Time-mated ewes were housed at 40°C from day 40 to 95 of gestation to produce IUGR lambs. From birth, IUGR lambs received daily IM injections of 0.8 μg/kg clenbuterol HCl (IUGR+CLEN; n = 11) or saline placebo (IUGR; n = 12). Placebo-injected controls (n = 13) were born to pair-fed thermoneutral ewes. Biometrics were assessed weekly and body composition was estimated by ultrasound and bioelectrical impedance analysis (BIA). Lambs were necropsied at 60 days of age. Results: Bodyweights were lighter (p ≤ 0.05) for IUGR and IUGR+CLEN lambs than for controls at birth, day 30, and day 60. Average daily gain was less (p ≤ 0.05) for IUGR lambs than controls and was intermediate for IUGR+CLEN lambs. At day 58, BIA-estimated whole-body fat-free mass and ultrasound-estimated loin eye area were less (p ≤ 0.05) for IUGR but not IUGR+CLEN lambs than for controls. At necropsy, loin eye area and flexor digitorum superficialis muscles were smaller (p ≤ 0.05) for IUGR but not IUGR+CLEN lambs than for controls. Longissimus dorsi protein content was less (p ≤ 0.05) and fat-to-protein ratio was greater (p ≤ 0.05) for IUGR but not IUGR+CLEN lambs than for controls. Semitendinosus from IUGR lambs had less (p ≤ 0.05) β2 adrenoreceptor content, fewer (p ≤ 0.05) proliferating myoblasts, tended to have fewer (p = 0.08) differentiated myoblasts, and had smaller (p ≤ 0.05) muscle fibers than controls. Proliferating myoblasts and fiber size were recovered (p ≤ 0.05) in IUGR+CLEN lambs compared to IUGR lambs, but β2 adrenoreceptor content and differentiated myoblasts were not recovered. Semitendinosus lipid droplets were smaller (p ≤ 0.05) in size for IUGR lambs than for controls and were further reduced (p ≤ 0.05) in size for IUGR+CLEN lambs. Conclusion: These findings show that clenbuterol improved IUGR deficits in muscle growth and some metabolic parameters even without recovering the deficit in β2 adrenoreceptor content. We conclude that IUGR muscle remained responsive to β2 adrenergic stimulation postnatal, which may be a strategic target for improving muscle growth and body composition in IUGR-born offspring.

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

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.

Fetal growth restriction followed by early catch-up growth impairs pancreatic islet morphology in male rats

Fetal growth restriction (FGR), followed by postnatal early catch-up growth, is associated with an increased risk of metabolic dysfunction, including type 2 diabetes in humans. This study aims to determine the effects of FGR and early catch-up growth after birth on the pathogenesis of type 2 diabetes, with particular attention to glucose tolerance, pancreatic islet morphology, and fibrosis, and to elucidate its mechanism using proteomics analysis. The FGR rat model was made by inducing mild intrauterine hypoperfusion using ameroid constrictors (ACs). On day 17 of pregnancy, ACs were affixed to the uterine and ovarian arteries bilaterally, causing a 20.9% reduction in birth weight compared to sham pups. On postnatal day 4 (P4), the pups were assigned to either the good nutrition (GN) groups with 5 pups per dam to ensure postnatal catch-up growth or poor nutrition groups with 15 pups per dam to maintain lower body weight. After weaning, all pups were fed regular chow food ad libitum (P21). Rats in both FGR groups developed glucose intolerance; however, male rats in the FGR good nutrition (FGR-GN) group also developed hypertriglyceridemia and dysmorphic pancreatic islets with fibrosis. A comprehensive and functional analysis of proteins expressed in the pancreas showed that FGR, followed by early catch-up growth, severely aggravated cell adhesion-related protein expression in male offspring. Thus, FGR and early catch-up growth caused pancreatic islet morphological abnormalities and fibrosis associated with the disturbance of cell adhesion-related protein expressions. These changes likely induce glucose intolerance and dyslipidemia in male rats.

Non-coding RNAs: The link between maternal malnutrition and offspring metabolism

Early life nutrition is associated with the development and metabolism in later life, which is known as the Developmental Origin of Health and Diseases (DOHaD). Epigenetics have been proposed as an important explanation for this link between early life malnutrition and long-term diseases. Non-coding RNAs (ncRNAs) may play a role in this epigenetic programming. The expression of ncRNAs (such as long non-coding RNA H19, microRNA-122, and circular RNA-SETD2) was significantly altered in specific tissues of offspring exposed to maternal malnutrition. Changes in these downstream targets of ncRNAs lead to abnormal development and metabolism. This review aims to summarize the existing knowledge on ncRNAs linking the maternal nutrition condition and offspring metabolic diseases, such as obesity, type 2 diabetes (T2D) and non-alcoholic fatty liver disease (NAFLD).

A Low Dose of Ouabain Alters the Metabolic Profile of Adult Rats Experiencing Intrauterine Growth Restriction in a Sex-Specific Manner

Intrauterine growth restriction (IUGR) increases the risk of type 2 diabetes mellitus (T2DM) and metabolic diseases. The pancreas of fetuses with IUGR is usually characterized by pancreatic dysplasia and reduced levels of insulin secretion caused by the diminished replication of β-cells. Previous studies showed that a low dose of ouabain could reduce the apoptosis of embryonic nephric cells during IUGR and partially restore the number of nephrons at birth. The rescued kidneys functioned well and decreased the prevalence of hypertension. Thus, we hypothesized that ouabain could rescue pancreatic development during IUGR and reduce the morbidity of T2DM and metabolic diseases. Maternal malnutrition was used to induce the IUGR model, and then a low dose of ouabain was administered to rats with IUGR during pregnancy. Throughout the experiment, we monitored the pattern of weight increase and evaluated the metabolic parameters in the offspring in different stages. Male, but not female, offspring in the IUGR group presented catch-up growth. Ouabain could benefit the impaired glucose tolerance of male offspring; however, this desirable effect was eliminated by aging. The insulin sensitivity was significantly impaired in male offspring with IUGR, but it was improved by ouabain, even during old age. However, in the female offspring, low birth weight appeared to be a beneficial factor even in old age; administering ouabain exacerbated these favorable effects. Our data suggested that IUGR influenced glucose metabolism in a sex-specific manner and ouabain treatment during pregnancy exerted strongly contrasting effects in male and female rats.

Small RNAs derived from tRNA fragmentation regulate the functional maturation of neonatal β cells

tRNA-derived fragments (tRFs) are an emerging class of small non-coding RNAs with distinct cellular functions. Here, we studied the contribution of tRFs to the regulation of postnatal β cell maturation, a critical process that may lead to diabetes susceptibility in adulthood. We identified three tRFs abundant in neonatal rat islets originating from 5' halves (tiRNA-5s) of histidine and glutamate tRNAs. Their inhibition in these islets reduced β cell proliferation and insulin secretion. Mitochondrial respiration was also perturbed, fitting with the mitochondrial enrichment of nuclear-encoded tiRNA-5^HisGTG and tiRNA-5^GluCTC. Notably, tiRNA-5 inhibition reduced Mpc1, a mitochondrial pyruvate carrier whose knock down largely phenocopied tiRNA-5 inhibition. tiRNA-5^HisGTG interactome revealed binding to Musashi-1, which was essential for the mitochondrial enrichment of tiRNA-5^HisGTG. Finally, tiRNA-5s were dysregulated in the islets of diabetic and diabetes-prone animals. Altogether, tiRNA-5s represent a class of regulators of β cell maturation, and their deregulation in neonatal islets may lead to diabetes susceptibility in adulthood.

Lessons from neonatal β-cell epigenomic for diabetes prevention and treatment

Pancreatic β-cell expansion and functional maturation during the birth-to-weaning period plays an essential role in the adaptation of plasma insulin levels to metabolic needs. These events are driven by epigenetic programs triggered by growth factors, hormones, and nutrients. These mechanisms operating in the neonatal period can be at least in part reactivated in adult life to increase the functional β-cell mass and face conditions of increased insulin demand such as obesity or pregnancy. In this review, we will highlight the importance of studying these signaling pathways and epigenetic programs to understand the causes of different forms of diabetes and to permit the design of novel therapeutic strategies to prevent and treat this metabolic disorder affecting hundreds of millions of people worldwide.

Prenatal Oxygen and Glucose Therapy Normalizes Insulin Secretion and Action in Growth Restricted Fetal Sheep

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.

Maternal antagonism of Glp1 reverses the adverse outcomes of sleeve gastrectomy on mouse offspring

Mothers that underwent bariatric surgery are at higher risk for delivering a small-for-gestational age (SGA) infant. This phenomenon is attributed to malabsorption and rapid weight loss following surgery. We compared pregnancy outcomes in lean mice that underwent sham surgery or sleeve gastrectomy (SG). SG led to a reduction in glucose levels and an increase in postprandial levels of glucagon-like peptide 1 (Glp1) without affecting mice weight during pregnancy. Pups of SG-operated mice (SG pups) were born SGA. The placenta and pancreas of the pups were not affected by SG, although a high-fat diet caused hepatic steatosis and glucose intolerance in male SG pups. Treatment with a Glp1 receptor antagonist during pregnancy normalized the birth weight of SG pups and diminished the adverse response to a high-fat diet without affecting glucose levels of pregnant mice. The antagonist did not affect the birth weight of pups of sham-operated mice. Our findings link elevated Glp1 signaling, rather than weight loss, to the increased prevalence of SGA births following bariatric surgery with metabolic consequences for the offspring. The long-term effects of bariatric surgery on the metabolic health of offspring of patients require further investigation.

Tissue-specific responses that constrain glucose oxidation and increase lactate production with the severity of hypoxemia in fetal sheep

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.

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

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.

Going Up Inflame: Reviewing the Underexplored Role of Inflammatory Programming in Stress-Induced Intrauterine Growth Restricted Livestock

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.

Pancreas deficiency modifies bone development in the ovine fetus near term

Hormones have an important role in the regulation of fetal growth and development, especially in response to nutrient availability in utero. Using micro-CT and an electromagnetic three-point bend test, this study examined the effect of pancreas removal at 0.8 fraction of gestation on the developing bone structure and mechanical strength in fetal sheep. When fetuses were studied at 10 and 25 days after surgery, pancreatectomy caused hypoinsulinaemia, hyperglycaemia and growth retardation which was associated with low plasma concentrations of leptin and a marker of osteoclast activity and collagen degradation. In pancreatectomized fetuses compared to control fetuses, limb lengths were shorter, and trabecular (Tb) bone in the metatarsi showed greater bone volume fraction, Tb thickness, degree of anisotropy and porosity, and lower fractional bone surface area and Tb spacing. Mechanical strength testing showed that pancreas deficiency was associated with increased stiffness and a greater maximal weight load at fracture in a subset of fetuses studied near term. Overall, pancreas deficiency in utero slowed the growth of the fetal skeleton and adapted the developing bone to generate a more compact and connected structure. Maintenance of bone strength in growth-retarded limbs is especially important in a precocial species in preparation for skeletal loading and locomotion at birth.

Diminished insulin sensitivity is associated with altered brain activation to food cues and with risk for obesity - Implications for individuals born small for gestational age

While classically linked to memory, the hippocampus is also a feeding behavior modulator due to its multiple interconnected pathways with other brain regions and expression of receptors for metabolic hormones. Here we tested whether variations in insulin sensitivity would be correlated with differential brain activation following exposure to palatable food cues, as well as with variations in implicit food memory in a cohort of healthy adolescents, some of whom were born small for gestational age (SGA). Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) was positively correlated with activation in the cuneus, and negatively correlated with activation in the middle frontal lobe, superior frontal gyrus and precuneus when presented with palatable food images versus non-food images in healthy adolescents. Additionally, HOMA-IR and insulinemia were higher in participants with impaired food memory. SGA individuals had higher snack caloric density and greater chance for impaired food memory. There was also an interaction between the HOMA-IR and birth weight ratio influencing external eating behavior. We suggest that diminished insulin sensitivity correlates with activation in visual attention areas and inactivation in inhibitory control areas in healthy adolescents. Insulin resistance also associated with less consistency in implicit memory for a consumed meal, which may suggest lower ability to establish a dietary pattern, and can contribute to obesity. Differences in feeding behavior in SGA individuals were associated with insulin sensitivity and hippocampal alterations, suggesting that cognition and hormonal regulation are important components involved in their food intake modifications throughout life.

Sexually dimorphic changes in the endocrine pancreas and skeletal muscle in young adulthood following intra-amniotic IGF-I treatment of growth-restricted fetal sheep

Fetal growth restriction (FGR) is associated with decreased insulin secretory capacity and decreased insulin sensitivity in muscle in adulthood. We investigated whether intra-amniotic IGF-I treatment in late gestation mitigated the adverse effects of FGR on the endocrine pancreas and skeletal muscle at 18 mo of age. Singleton-bearing ewes underwent uterine artery embolization between 103 and 107 days of gestational age, followed by 5 once-weekly intra-amniotic injections of 360-µg IGF-I (FGRI) or saline (FGRS) and were compared with an unmanipulated control group (CON). We measured offspring pancreatic endocrine cell mass and pancreatic and skeletal muscle mRNA expression at 18 mo of age (n = 7-9/sex/group). Total α-cell mass was increased ∼225% in FGRI males versus CON and FGRS males, whereas β-cell mass was not different between groups of either sex. Pancreatic mitochondria-related mRNA expression was increased in FGRS females versus CON (NRF1, MTATP6, UCP2), and FGRS males versus CON (TFAM, NRF1, UCP2) but was largely unchanged in FGRI males versus CON. In skeletal muscle, mitochondria-related mRNA expression was decreased in FGRS females versus CON (PPARGC1A, TFAM, NRF1, UCP2, MTATP6), FGRS males versus CON (NRF1 and UCP2), and FGRI females versus CON (TFAM and UCP2), with only MTATP6 expression decreased in FGRI males versus CON. Although the window during which IGF-I treatment was delivered was limited to the final 5 wk of gestation, IGF-I therapy of FGR altered the endocrine pancreas and skeletal muscle in a sex-specific manner in young adulthood.NEW & NOTEWORTHY Fetal growth restriction (FGR) is associated with compromised metabolic function throughout adulthood. Here, we explored the long-term effects of fetal IGF-I therapy on the adult pancreas and skeletal muscle. This is the first study demonstrating that IGF-I therapy of FGR has sex-specific long-term effects at both the tissue and molecular level on metabolically active tissues in adult sheep.

Placental mTOR complex 1 regulates fetal programming of obesity and insulin resistance in mice

Fetal growth restriction, or low birth weight, is a strong determinant for eventual obesity and type 2 diabetes. Clinical studies suggest placental mechanistic target of rapamycin (mTOR) signaling regulates fetal birth weight and the metabolic health trajectory of the offspring. In the current study, we used a genetic model with loss of placental mTOR function (mTOR-KO^Placenta) to test the direct role of mTOR signaling on birth weight and metabolic health in the adult offspring. mTOR-KO^Placenta animals displayed reduced placental area and total weight, as well as fetal body weight at embryonic day (E) 17.5. Birth weight and serum insulin levels were reduced; however, β cell mass was normal in mTOR-KO^Placenta newborns. Adult mTOR-KO^Placenta offspring, under a metabolic high-fat challenge, displayed exacerbated obesity and metabolic dysfunction compared with littermate controls. Subsequently, we tested whether enhancing placental mTOR complex 1 (mTORC1) signaling, via genetic ablation of TSC2, in utero would improve glucose homeostasis in the offspring. Indeed, increased placental mTORC1 conferred protection from diet-induced obesity in the offspring. In conclusion, placental mTORC1 serves as a mechanistic link between placental function and programming of obesity and insulin resistance in the adult offspring.

Strategies to improve neurodevelopmental outcomes in babies at risk of neonatal hypoglycaemia

Neonatal hypoglycaemia is associated with adverse development, particularly visual-motor and executive function impairment, in childhood. As neonatal hypoglycaemia is common and frequently asymptomatic in at-risk babies-ie, those born preterm, small or large for gestational age, or to mothers with diabetes, it is recommended that these babies are screened for hypoglycaemia in the first 1-2 days after birth with frequent blood glucose measurements. Neonatal hypoglycaemia can be prevented and treated with buccal dextrose gel, and it is also common to treat babies with hypoglycaemia with infant formula and intravenous dextrose. However, it is uncertain if screening, prophylaxis, or treatment improves long-term outcomes of babies at risk of neonatal hypoglycaemia. This narrative review assesses the latest evidence for screening, prophylaxis, and treatment of neonates at risk of hypoglycaemia to improve long-term neurodevelopmental outcomes.

Perinatal Nutritional and Metabolic Pathways: Early Origins of Chronic Lung Diseases

Lung development is not completed at birth, but expands beyond infancy, rendering the lung highly susceptible to injury. Exposure to various influences during a critical window of organ growth can interfere with the finely-tuned process of development and induce pathological processes with aberrant alveolarization and long-term structural and functional sequelae. This concept of developmental origins of chronic disease has been coined as perinatal programming. Some adverse perinatal factors, including prematurity along with respiratory support, are well-recognized to induce bronchopulmonary dysplasia (BPD), a neonatal chronic lung disease that is characterized by arrest of alveolar and microvascular formation as well as lung matrix remodeling. While the pathogenesis of various experimental models focus on oxygen toxicity, mechanical ventilation and inflammation, the role of nutrition before and after birth remain poorly investigated. There is accumulating clinical and experimental evidence that intrauterine growth restriction (IUGR) as a consequence of limited nutritive supply due to placental insufficiency or maternal malnutrition is a major risk factor for BPD and impaired lung function later in life. In contrast, a surplus of nutrition with perinatal maternal obesity, accelerated postnatal weight gain and early childhood obesity is associated with wheezing and adverse clinical course of chronic lung diseases, such as asthma. While the link between perinatal nutrition and lung health has been described, the underlying mechanisms remain poorly understood. There are initial data showing that inflammatory and nutrient sensing processes are involved in programming of alveolarization, pulmonary angiogenesis, and composition of extracellular matrix. Here, we provide a comprehensive overview of the current knowledge regarding the impact of perinatal metabolism and nutrition on the lung and beyond the cardiopulmonary system as well as possible mechanisms determining the individual susceptibility to CLD early in life. We aim to emphasize the importance of unraveling the mechanisms of perinatal metabolic programming to develop novel preventive and therapeutic avenues.

Reduced glucose-stimulated insulin secretion following a 1-wk IGF-1 infusion in late gestation fetal sheep is due to an intrinsic islet defect

Insulin and insulin-like growth factor-1 (IGF-1) are fetal hormones critical to establishing normal fetal growth. Experimentally elevated IGF-1 concentrations during late gestation increase fetal weight but lower fetal plasma insulin concentrations. We therefore hypothesized that infusion of an IGF-1 analog for 1 wk into late gestation fetal sheep would attenuate fetal glucose-stimulated insulin secretion (GSIS) and insulin secretion in islets isolated from these fetuses. Late gestation fetal sheep received infusions with IGF-1 LR3 (IGF-1, n = 8), an analog of IGF-1 with low affinity for the IGF binding proteins and high affinity for the IGF-1 receptor, or vehicle control (CON, n = 9). Fetal GSIS was measured with a hyperglycemic clamp (IGF-1, n = 8; CON, n = 7). Fetal islets were isolated, and insulin secretion was assayed in static incubations (IGF-1, n = 8; CON, n = 7). Plasma insulin and glucose concentrations in IGF-1 fetuses were lower compared with CON (P = 0.0135 and P = 0.0012, respectively). During the GSIS study, IGF-1 fetuses had lower insulin secretion compared with CON (P = 0.0453). In vitro, glucose-stimulated insulin secretion remained lower in islets isolated from IGF-1 fetuses (P = 0.0447). In summary, IGF-1 LR3 infusion for 1 wk into fetal sheep lowers insulin concentrations and reduces fetal GSIS. Impaired insulin secretion persists in isolated fetal islets indicating an intrinsic islet defect in insulin release when exposed to IGF-1 LR3 infusion for 1 wk. We speculate this alteration in the insulin/IGF-1 axis contributes to the long-term reduction in β-cell function in neonates born with elevated IGF-1 concentrations following pregnancies complicated by diabetes or other conditions associated with fetal overgrowth.NEW & NOTEWORTHY After a 1-wk infusion of IGF-1 LR3, late gestation fetal sheep had lower plasma insulin and glucose concentrations, reduced fetal glucose-stimulated insulin secretion, and decreased fractional insulin secretion from isolated fetal islets without differences in pancreatic insulin content.

Islet Epigenetic Impacts on β-Cell Identity and Function

The development and maintenance of differentiation is vital to the function of mature cells. Terminal differentiation is achieved by locking in the expression of genes essential for the function of those cells. Gene expression and its memory through generations of cell division is controlled by transcription factors and a host of epigenetic marks. In type 2 diabetes, β cells have altered gene expression compared to controls, accompanied by altered chromatin marks. Mutations, diet, and environment can all disrupt the implementation and preservation of the distinctive β-cell transcriptional signature. Understanding of the full complement of genomic control in β cells is still nascent. This article describes the known effects of histone marks and variants, DNA methylation, how they are regulated in the β cell, and how they affect cell-fate specification, maintenance, and lineage propagation. © 2021 American Physiological Society. Compr Physiol 11:1-18, 2021.

Maternofetal inflammation induced for 2 wk in late gestation reduced birth weight and impaired neonatal growth and skeletal muscle glucose metabolism in lambs

Intrauterine stress impairs growth and metabolism in the fetus and offspring. We recently found that sustained maternofetal inflammation resulted in intrauterine growth-restricted (MI-IUGR) fetuses with asymmetric body composition, impaired muscle glucose metabolism, and β-cell dysfunction near term. These fetuses also exhibited heightened inflammatory tone, which we postulated was a fetal programming mechanism for the IUGR phenotype. Thus, the objective of this study was to determine whether poor growth and metabolism persisted in MI-IUGR lambs after birth. Polypay ewes received serial lipopolysaccharide or saline injections in the first 2 wk of the third trimester of pregnancy to produce MI-IUGR (n = 13) and control (n = 12) lambs, respectively. Lambs were catheterized at 25 d of age. β-Cell function was assessed at 29 d, hindlimb glucose metabolism at 30 d, and daily blood parameters from day 26 to 31. Glucose metabolism was also assessed in flexor digitorum superficialis (FDS) muscle isolated at necropsy on day 31. Asymmetric body composition persisted in MI-IUGR neonates, as these lambs were lighter (P < 0.05) than controls at birth and 31 d, but body and cannon bone lengths did not differ at either age. FDS muscles from MI-IUGR lambs were smaller (P < 0.05) and exhibited reduced (P < 0.05) glucose oxidation and Akt phosphorylation but similar glucose uptake compared with controls when incubated in basal or insulin-spiked media. Similarly, hindlimb glucose oxidation was reduced (P < 0.05) in MI-IUGR lambs under basal and hyperinsulinemic conditions, but hindlimb glucose utilization did not differ from controls. Circulating urea nitrogen and cholesterol were reduced (P < 0.05), and triglycerides, high-density lipoprotein cholesterol, and glucose-to-insulin ratios were increased (P < 0.05) in MI-IUGR lambs. Glucose and insulin concentrations did not differ between groups during basal or hyperglycemic conditions. Although circulating monocyte and granulocyte concentrations were greater (P < 0.05) in MI-IUGR lambs, plasma tumor necrosis factor α (TNFα) was reduced (P < 0.05). FDS muscle contained greater (P < 0.05) TNF receptor 1 (TNFR1) and IκBα protein content. These findings indicate that maternofetal inflammation in late pregnancy results in fetal programming that impairs growth capacity, muscle glucose oxidation, and lipid homeostasis in offspring. Inflammatory indicators measured in this study appear to reflect heightened cytokine sensitivity in muscle and compensatory systemic responses to it.

Prolonged transitional neonatal hypoglycaemia: characterisation of a clinical syndrome

BACKGROUND

We performed a case-control study to characterise infants with "prolonged transitional hypoglycaemia".

METHODS

Cases were born ≥36 weeks' gestation; had ≥1 hypoglycaemic episode <72 h and ≥72 h; received ongoing treatment for hypoglycaemia ≥72 h; and were without congenital disorders or acute illness. Cases were compared to controls born ≥36 weeks' with brief transitional hypoglycaemia, resolving <72 h.

RESULTS

39/471 infants screened met case definition: 71.8% were male, 61.5% were small-for-gestational-age (SGA), and most were admitted <6 h. Compared to controls (N = 75), key risk factors for prolonged transitional hypoglycaemia were SGA (OR = 6.4, 95%CI 2.7-15.1), severe/recurrent hypoglycaemia <24 h (OR = 16.7, 95%CI 4.5-16.1), intravenous glucose bolus <24 h (OR = 26.6, 95%CI 9.4-75.1) and maximum glucose delivery rate <48 h of ≥8 mg/kg/min (OR = 25.5, 95%CI 7.7-84.1).

CONCLUSIONS

Infants with prolonged transitional hypoglycaemia are predominantly male, SGA and have early severe/recurrent hypoglycaemia requiring glucose boluses and high glucose delivery rates in the first 24-48 h.

Immune dysfunction in developmental programming of type 2 diabetes mellitus

Intrauterine growth restriction (IUGR) is a common complication of pregnancy and increases the risk of the offspring developing type 2 diabetes mellitus (T2DM) later in life. Alterations in the immune system are implicated in the pathogenesis of IUGR-induced T2DM. The development of the fetal immune system is a delicate balance as it must remain tolerant of maternal antigens whilst also preparing for the post-birth environment. In addition, the fetal immune system is susceptible to an altered intrauterine milieu caused by maternal and placental inflammatory mediators or secondary to nutrient and oxygen deprivation. Pancreatic-resident macrophages populate the pancreas during fetal development, and their phenotype is dynamic through the neonatal period. Furthermore, macrophages in the islets are instrumental in islet development as they influence β-cell proliferation and islet neogenesis. In addition, cytokines, derived from β-cells and macrophages, are important to islet homeostasis in the fetus and adult and, when perturbed, can cause islet dysfunction. Several activated immune pathways have been identified in the islets of people who experienced IUGR, with alternations in the levels of IL-1β and IL-4 as well as changes in TGFβ signalling. Leptin levels are also altered. Immunomodulation has shown therapeutic benefit in T2DM and might be particularly useful in IUGR-induced T2DM.

Maternal nutrient restriction alters endocrine pancreas development in fetal heifers

Maternal nutrient restriction during pregnancy alters fetal programming, which modifies the growth and health of the offspring in postnatal life. In cattle, nutrient restriction during pregnancy can be a result of environmental or economic factors, but little is known about how it alters the physiology of the fetus and affects future reproductive or growth efficiency. This study used female monozygotic twins, produced through in vitro fertilization and embryo splitting, to determine the effect of moderate maternal nutrient restriction on fetal development. Recipient Angus cross heifers pregnant with one twin were fed a diet meeting 100% National Research Council (NRC) total energy requirements (n = 4; control), whereas recipient heifers pregnant with the second twin were fed at 70% of NRC total energy requirements (n = 4; restricted) from gestational day (GD) 158 to GD 265 in Calan gate feeders. Recipient heifers were killed at GD 265. Change in maternal metabolic body weight was greater from zero in restricted heifers than controls (P < 0.05); restricted heifers lost weight during the nutrient restriction period. There was no difference in last rib back fat or rib eye area between groups (P > 0.10). There was no difference in fetal weight, uterine weight, or total placentome weight between groups (P > 0.10). The pancreas weight was reduced in restricted fetuses compared with control fetuses (P < 0.01), but there were no other differences in fetal organ weights (P > 0.10). Plasma insulin concentrations were reduced in restricted fetuses compared with controls (P < 0.01), but there was no effect of maternal diet on plasma glucose or glucagon concentrations in the fetus (P > 0.10). Histological analyses of the fetal pancreas revealed no differences in endocrine cell number or localization. Results indicate that a modest late gestation nutritional restriction impairs development of the fetal pancreas in the cow. Additional research will be needed to determine if these developmental changes lead to altered glucose and insulin homeostasis in the adult.

Chronic Fetal Leucine Infusion Does Not Potentiate Glucose-Stimulated Insulin Secretion or Affect Pancreatic Islet Development in Late-Gestation Growth-Restricted Fetal Sheep

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.

Developmental origins of metabolic diseases

Almost 2 billion adults in the world are overweight, and more than half of them are classified as obese, while nearly one-third of children globally experience poor growth and development. Given the vast amount of knowledge that has been gleaned from decades of research on growth and development, a number of questions remain as to why the world is now in the midst of a global epidemic of obesity accompanied by the "double burden of malnutrition," where overweight coexists with underweight and micronutrient deficiencies. This challenge to the human condition can be attributed to nutritional and environmental exposures during pregnancy that may program a fetus to have a higher risk of chronic diseases in adulthood. To explore this concept, frequently called the developmental origins of health and disease (DOHaD), this review considers a host of factors and physiological mechanisms that drive a fetus or child toward a higher risk of obesity, fatty liver disease, hypertension, and/or type 2 diabetes (T2D). To that end, this review explores the epidemiology of DOHaD with discussions focused on adaptations to human energetics, placental development, dysmetabolism, and key environmental exposures that act to promote chronic diseases in adulthood. These areas are complementary and additive in understanding how providing the best conditions for optimal growth can create the best possible conditions for lifelong health. Moreover, understanding both physiological as well as epigenetic and molecular mechanisms for DOHaD is vital to most fully address the global issues of obesity and other chronic diseases.

Effects of different diet-induced postnatal catch-up growth on glycolipid metabolism in intrauterine growth retardation male rats

A number of studies have reported the occurrence of long-term metabolic disorders in mammals following intrauterine growth retardation (IUGR). However, the effects of dietary patterns during IUGR have not been fully elucidated. The present study aimed to evaluate the effects of different dietary patterns during critical growth windows on metabolic outcomes in the offspring of rats with IUGR. Male offspring rats from mothers fed either a normal or low-protein diet were randomly assigned to one of the following groups: Normal diet throughout pregnancy, lactation and after weaning (CON); normal diet throughout pregnancy and high-fat diet throughout lactation and after weaning (N + H + H); low-protein diet throughout pregnancy and high-fat diet throughout lactation and after weaning (IUGR + H + H); low-protein diet throughout pregnancy and lactation and high-fat diet after weaning (IUGR + L + H); and low-protein diet throughout pregnancy and normal diet throughout lactation and after weaning. During lactation, the male offspring in the N + H + H group exhibited the fastest growth rate, whereas the slowest rate was in the IUGR + L + H group. Following weaning, all IUGR groups demonstrated significant catch-up growth. Abnormal insulin tolerance were observed in the N + H + H, IUGR + H + H and IUGR + L + H groups and insulin sensitivity was decreased in IUGR + L + H group. The triglycerides/high-density lipoprotein ratio in the IUGR + L + H group was significantly higher compared with in the other groups. The abdominal circumference, Lee's index and adipocyte diameter of IUGR groups were significantly increased compared with the CON group. High levels of leptin and interleukin-6 in adipose tissues, and low adiponectin were observed in the IUGR + L + H group. Different dietary patterns during specific growth windows showed numerous impacts on glycolipid metabolism in IUGR offspring. The present study elucidated the mechanisms and potential options for IUGR treatment and prevention.

Maternal low-protein diet on the last week of pregnancy contributes to insulin resistance and β-cell dysfunction in the mouse offspring

Maternal low-protein diet (LP) throughout gestation affects pancreatic β-cell fraction of the offspring at birth, thus increasing their susceptibility to metabolic dysfunction and type 2 diabetes in adulthood. The present study sought to strictly examine the effects of LP during the last week of gestation (LP12.5) alone as a developmental window for β-cell programming and metabolic dysfunction in adulthood. Islet morphology analysis revealed normal β-cell fraction in LP12.5 newborns. Normal glucose tolerance was observed in 6- to 8-wk-old male and female LP12.5 offspring. However, male LP12.5 offspring displayed glucose intolerance and reduced insulin sensitivity associated with β-cell dysfunction with aging. High-fat diet exposure of metabolically normal 12-wk-old male LP12.5 induced glucose intolerance due to increased body weight, insulin resistance, and insufficient β-cell mass adaptation despite higher insulin secretion. Assessment of epigenetic mechanisms through microRNAs (miRs) by a real-time PCR-based microarray in islets revealed elevation in miRs that regulate insulin secretion (miRs 342, 143), insulin resistance (miR143), and obesity (miR219). In the islets, overexpression of miR143 reduced insulin secretion in response to glucose. In contrast to the model of LP exposure throughout pregnancy, islet protein levels of mTOR and pancreatic and duodenal homeobox 1 were normal in LP12.5 islets. Collectively, these data suggest that LP diet during the last week of pregnancy is critical and sufficient to induce specific and distinct developmental programming effects of tissues that control glucose homeostasis, thus causing permanent changes in specific set of microRNAs that may contribute to the overall vulnerability of the offspring to obesity, insulin resistance, and type 2 diabetes.

Leucine acutely potentiates glucose-stimulated insulin secretion in fetal sheep

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.

The mechanisms of lncRNA Tug1 in islet dysfunction in a mouse model of intrauterine growth retardation

Taurine upregulated gene 1 (Tug1) is a novel lncRNA that participates in growth, and the abnormal expression of Tug1 related to mouse islet cell dysfunction. A recent study revealed that intrauterine growth retardation (IUGR) related to the pathogenesis of diabetes. Here, we aimed to explore the role and mechanism of Tug1 in IUGR-mediated islet dysfunction. We observed that newborn IUGR mice had lower body and pancreas weight and smaller islets than newborn control mice. After IUGR mice were given a normal diet, they showed catch-up growth and abnormal glucose tolerance; however, the pancreas/body weight ratio remained low. Blood glucose, serum insulin and related gene expression showed mild recovery after overexpression of Tug1 in IUGR mice. Furthermore, Tug1 was enriched in the nuclei of MIN6 cells. Using RIP and CHIP analyses we found that Tug1 could regulate Hes1 expression by binding to EZH2 to affect insulin synthesis in MIN6 cells. These findings indicate that lncRNA Tug1 could regulate the expression of Hes1 via EZH2-driven H3K27 methylation and affect insulin production. SIGNIFICANCE OF THE STUDY: This study suggests Tug1 as a novel biomarker, as it was shown to regulate β cell function and is worthy of further investigation due to its potential for diabetes treatment.

A Chronic Fetal Leucine Infusion Potentiates Fetal Insulin Secretion and Increases Pancreatic Islet Size, Vascularity, and β Cells in Late-Gestation Sheep

BACKGROUND

Infusion of a complete amino acid mixture into normal late-gestation fetal sheep potentiates glucose-stimulated insulin secretion (GSIS). Leucine acutely stimulates insulin secretion in late-gestation fetal sheep and isolated fetal sheep islets in vitro.

OBJECTIVES

We hypothesized that a 9-d leucine infusion would potentiate GSIS in fetal sheep.

METHODS

Columbia-Rambouillet fetal sheep at 126 days of gestation received a 9-d leucine infusion to achieve a 50%-100% increase in leucine concentrations or a control infusion. At the end of the infusion we measured GSIS, pancreatic morphology, and expression of pancreatic mRNAs. Pancreatic islet endothelial cells (ECs) were isolated from fetal sheep and incubated with supplemental leucine or vascular endothelial growth factor A (VEGFA) followed by collection of mRNA. Data measured at multiple time points were compared with a repeated-measures 2-factor ANOVA. Data measured at 1 time point were compared using Student's t test or the Mann-Whitney test.

RESULTS

Glucose-stimulated insulin concentrations were 80% higher in leucine-infused (LEU) fetuses than in controls (P < 0.05). In the pancreas, LEU fetuses had a higher proportion of islets >5000 μm2 than controls (75% more islets >5000 μm2; P < 0.05) and a larger proportion of the pancreas that stained for β cells (12% greater; P < 0.05). Pancreatic and pancreatic islet vascularity were both 25% greater in LEU fetuses (P < 0.05). Pancreatic VEGFA and hepatocyte growth factor (HGF) mRNA expressions were 38% and 200% greater in LEU fetuses than in controls (P < 0.05), respectively. In isolated islet ECs, HGF mRNA was 20% and 50% higher after incubation in supplemental leucine (P < 0.05) or VEGFA (P < 0.01), respectively.

CONCLUSIONS

A 9-d leucine infusion potentiates fetal GSIS, demonstrating that glucose and leucine act synergistically to stimulate insulin secretion in fetal sheep. A greater proportion of the pancreas being comprised of β cells and higher pancreatic vascularity contributed to the higher GSIS.

Associations of birthweight and history of childhood obesity with beta cell mass in Japanese adults

AIMS/HYPOTHESIS

Low birthweight is associated with a high risk of diabetes, but there are no reports discussing birthweight and pancreatic tissues in humans. The purpose of this study was to examine the correlation between birthweight and beta and alpha cell mass in humans.

METHODS

Sixty-four Japanese adults with and without diabetes who underwent pancreatectomy and were able to recall their weight history including birthweight were included. Pancreatic tissues were stained for insulin and glucagon, and fractional beta cell area (BCA) and alpha cell area (ACA) were quantified. Islet size and density and beta cell replication were also quantified and their associations with birthweight were evaluated.

RESULTS

In participants without diabetes, there was a weak positive correlation between birthweight and BCA (R = 0.34, p = 0.03). The group with a history of childhood obesity, but not the group with a history of obesity in adulthood only, showed higher BCA compared with those without a history of obesity (1.78 ± 0.74% vs 0.99 ± 0.53%, p = 0.01), and the correlation coefficient between birthweight and BCA increased after excluding those with a history of childhood obesity (R = 0.51, p < 0.01). In those with diabetes, there was no correlation between birthweight and BCA. No correlation was found between birthweight and ACA in either those with or without diabetes.

CONCLUSIONS/INTERPRETATION

Birthweight and beta, but not alpha, cell mass are positively correlated in non-diabetic adults, and a history of childhood obesity may affect beta cell mass. Graphical abstract.

Sex Differences Across the Lifespan: A Focus on Cardiometabolism

Women's health and sex differences research remain understudied. In 2016, to address the topic of sex differences, the Center for Women' s Health Research (CWHR) at the University of Colorado (cwhr@ucdenver.edu) held its inaugural National Conference, "Sex Differences Across the Lifespan: A Focus on Metabolism" and published a report summarizing the presentations. Two years later, in 2018, CWHR organized the 2nd National Conference. The research presentations and discussions from the 2018 conference also addressed sex differences across the lifespan with a focus on cardiometabolism and expanded the focus by including circadian physiology and effects of sleep on cardiometabolic health. Over 100 participants, including basic scientists, clinicians, policymakers, advocacy group leaders, and federal agency leadership participated. The meeting proceedings reveal that although exciting advances in the area of sex differences have taken place, significant questions and gaps remain about women's health and sex differences in critical areas of health. Identifying these gaps and the subsequent research that will result may lead to important breakthroughs.

Dietary Leucine Supplementation Restores Serum Glucose Levels, and Modifying Hepatic Gene Expression Related to the Insulin Signal Pathway in IUGR Piglets

Simple Summary

Intrauterine malnutrition may compromise the size and structure of fetal organs and tissues, which leads to lower birth weight and a slower rate of growth after weaning. Intrauterine growth restriction/retardation (IUGR) impairs pancreas function, resulting in the decreased glucose levels in serum. Leucine, one of branched chain amino acids, is an essential amino acid and the substrate of protein synthesis. Leucine also acts as a major regulator of hormone signal transduction, like insulin. Dietary branched chain amino acids or leucine have beneficial effects on the glucose metabolism and glycogen synthesis of muscle. Leucine supplementation improves the insulin sensitivity in liver and muscle and then influences the systemic glucose homeostasis. However, it is still unclear whether leucine supplementation would alter insulin sensitivity in IUGR neonatal piglets. Our results showed that dietary leucine supplementation restored serum glucose concentrations, increased insulin and creatinine concentrations, and enhanced protein kinase adenosine monophosphate-activated γ 3-subunit and glucose transporter type 2 expression. These findings suggest that leucine might play a positive role in hepatic lipid metabolism and glucose metabolism in IUGR.

Abstract

This study aimed to investigate the effects of leucine with different levels on the insulin resistance in intrauterine growth restriction/retardation (IUGR) piglets. Thirty-two weaned piglets were arranged in a 2 × 2 factorial design and four treatments (n = 8) were as follow: (1) normal weaned piglets fed a basal diet (CONT), (2) IUGR weaned piglets fed a basal diet (IUGR), (3) normal weaned piglets fed a basal diet with the addition of 0.35% l-leucine (C-LEU), and (4) IUGR fed a basal diet with the addition of 0.35% l-leucine (I-LEU) for a 21-days trial. The results showed that compared to the IUGR group, the I-LEU group had higher final body weight and body weight gain, higher serum glucose concentrations, and higher serum insulin concentrations (p < 0.05). The gene expression of phosphatidylinositol 3-kinase p110 gamma, protein kinase adenosine monophosphate-activated γ 3-subunit, glycogen synthase kinase-3 alpha, and glucose transporter type 2 were increased in the I-LEU group as compared to the IUGR group (p < 0.05). It was concluded that dietary leucine supplementation restored serum glucose concentrations, increased insulin and creatinine concentrations, and enhanced protein kinase adenosine monophosphate-activated γ 3-subunit and glucose transporter type 2 expression, suggesting that leucine might play a positive role in hepatic lipid metabolism and glucose metabolism in IUGR.

[Establishment of an ovalbumin-induced bronchial asthma model in mice with intrauterine growth retardation]

OBJECTIVE

To establish and evaluate an ovalbumin (OVA)-induced bronchial asthma model in mice with intrauterine growth retardation (IUGR), and to explore the molecular mechanism of relationship between IUGR and asthma.

METHODS

A total of 16 pregnant BALB/c female mice were divided into a low-protein diet group (n=8) and a normal-protein diet group (n=8), which were fed with low-protein (8%) diet and normal-protein (20%) diet respectively. The neonatal mice were weighed 6 hours after birth. Sixteen male neonatal mice with IUGR were randomly chosen from the low-protein diet group and enrolled in the IUGR group, and 16 male neonatal mice from the normal-protein diet group were enrolled in the control group. Blood samples were collected from the mice in both groups for testing of blood glucose. Enzyme-linked immunosorbent assay (ELISA) was used to determine serum insulin level. The mice in the control group were randomized into a control + PBS group and a control + OVA group (n=8 each). The mice in the IUGR group were randomized into an IUGR + PBS group and an IUGR + OVA group (n=8 each). Six-week-old mice in the control + OVA and IUGR + OVA groups were subjected to intraperitoneal injection of 2 mg/mL OVA for sensitization and aerosol inhalation of 1% OVA for challenge. Mice in the control + PBS group and the IUGR + PBS group were treated with an equivalent amount of PBS. ELISA was used to determine serum IgE level in the mice in each group. Bronchoalveolar lavage fluid (BLF) was collected from the mice in each group for cell counting. The lung tissue of the mice in each group was stained with hematoxylin and eosin to observe pathological changes.

RESULTS

The body weight at 6 hours after birth was significantly lower for neonatal mice in the low-protein diet group compared with those in the normal-protein diet group (P<0.01). The IUGR group had a significantly lower serum insulin level than the control group (P<0.01). The IUGR + PBS group had a significantly lower IgE level than the control + PBS group (P<0.01). Compared with the control + PBS and IUGR + PBS groups, the control + OVA and IUGR + OVA groups had a significantly increased IgE level, and the IgE level was significantly higher in the IUGR + OVA group than in the control + OVA group (P<0.01). Compared with the control + PBS and IUGR + PBS groups, the control + OVA and IUGR + OVA groups had significantly increased counts of leukocytes, eosinophils, lymphocytes, and macrophages in the BLF (P<0.01). The pulmonary alveoli of OVA-induced IUGR mice showed massive inflammatory cell infiltration and damage of intercellular continuity. Meanwhile, airway epithelial cell proliferation, bronchial wall thickening, bronchial lumen narrowing, and massive inflammatory cell infiltration around the bronchi and the vascular wall were observed.

CONCLUSIONS

An OVA-induced bronchial asthma model has been successfully established in the mice with IUGR induced by low-protein diet, which provides a basis for further study of the molecular mechanism of relationship between IUGR and airway inflammation.

[Establishment of an ovalbumin-induced bronchial asthma model in mice with intrauterine growth retardation]

OBJECTIVE

To establish and evaluate an ovalbumin (OVA)-induced bronchial asthma model in mice with intrauterine growth retardation (IUGR), and to explore the molecular mechanism of relationship between IUGR and asthma.

METHODS

A total of 16 pregnant BALB/c female mice were divided into a low-protein diet group (n=8) and a normal-protein diet group (n=8), which were fed with low-protein (8%) diet and normal-protein (20%) diet respectively. The neonatal mice were weighed 6 hours after birth. Sixteen male neonatal mice with IUGR were randomly chosen from the low-protein diet group and enrolled in the IUGR group, and 16 male neonatal mice from the normal-protein diet group were enrolled in the control group. Blood samples were collected from the mice in both groups for testing of blood glucose. Enzyme-linked immunosorbent assay (ELISA) was used to determine serum insulin level. The mice in the control group were randomized into a control + PBS group and a control + OVA group (n=8 each). The mice in the IUGR group were randomized into an IUGR + PBS group and an IUGR + OVA group (n=8 each). Six-week-old mice in the control + OVA and IUGR + OVA groups were subjected to intraperitoneal injection of 2 mg/mL OVA for sensitization and aerosol inhalation of 1% OVA for challenge. Mice in the control + PBS group and the IUGR + PBS group were treated with an equivalent amount of PBS. ELISA was used to determine serum IgE level in the mice in each group. Bronchoalveolar lavage fluid (BLF) was collected from the mice in each group for cell counting. The lung tissue of the mice in each group was stained with hematoxylin and eosin to observe pathological changes.

RESULTS

The body weight at 6 hours after birth was significantly lower for neonatal mice in the low-protein diet group compared with those in the normal-protein diet group (P<0.01). The IUGR group had a significantly lower serum insulin level than the control group (P<0.01). The IUGR + PBS group had a significantly lower IgE level than the control + PBS group (P<0.01). Compared with the control + PBS and IUGR + PBS groups, the control + OVA and IUGR + OVA groups had a significantly increased IgE level, and the IgE level was significantly higher in the IUGR + OVA group than in the control + OVA group (P<0.01). Compared with the control + PBS and IUGR + PBS groups, the control + OVA and IUGR + OVA groups had significantly increased counts of leukocytes, eosinophils, lymphocytes, and macrophages in the BLF (P<0.01). The pulmonary alveoli of OVA-induced IUGR mice showed massive inflammatory cell infiltration and damage of intercellular continuity. Meanwhile, airway epithelial cell proliferation, bronchial wall thickening, bronchial lumen narrowing, and massive inflammatory cell infiltration around the bronchi and the vascular wall were observed.

CONCLUSIONS

An OVA-induced bronchial asthma model has been successfully established in the mice with IUGR induced by low-protein diet, which provides a basis for further study of the molecular mechanism of relationship between IUGR and airway inflammation.

Label-Free Proteomics of the Fetal Pancreas Identifies Deficits in the Peroxisome in Rats with Intrauterine Growth Restriction

Aim

The objective of the present study was to identify differentially expressed proteins (DEPs) in the pancreas of a fetus with intrauterine growth restriction (IUGR) and to investigate the molecular mechanisms leading to adulthood diabetes in IUGR.

Methods

The IUGR rat model was induced by maternal protein malnutrition. The fetal pancreas was collected at embryonic day 20 (E20). Protein was extracted, pooled, and subjected to label-free quantitative proteomic analysis. Bioinformatics analysis (GO and IPA) was performed to define the pathways and networks associated with DEPs. LC-MS results were confirmed by western blotting and/or quantitative PCR (q-PCR). The principal parameters of oxidative stress-superoxide dismutase (Sod) were determined in blood samples of fetal rats.

Results

A total of 57 DEPs (27 upregulated, 30 downregulated) were identified with a 1.5-fold change threshold and a p value ≤ 0.05 between the IUGR and the control pancreas. Bioinformatics analysis revealed that these proteins play important roles in peroxisome biogenesis and fission, fatty acid beta-oxidation (FAO), mitotic cell cycle, and histone modification. The peroxin Pex14 was downregulated in the IUGR pancreas as confirmed by western blotting and q-PCR. Pmp70, a peroxisomal membrane protein involved in the transport of fatty acids, was upregulated. Hsd17b4 and Acox1/2, which catalyze different steps of peroxisomal FAO, were dysregulated. Sod plasma concentrations in the IUGR fetus were higher than those in the control, suggesting partial compensation for oxidative stress. Multiple DEPs were related to the regulation of the cell cycle, including reduced Cdk1, Mcm2, and Brd4. The histone acetylation regulators Hdac1/2 were downregulated, whereas Sirt1/3 and acetylated H3K56 were increased in the IUGR fetal pancreas.

Conclusion

The present study identified DEPs in the fetal pancreas of IUGR rats by proteomic analysis. Downregulation of pancreas peroxins and dysregulation of enzymes involved in peroxisomal FAO may impair the biogenesis and function of the peroxisome and may underlie the development of T2 diabetes mellitus in adult IUGR rats. Disorders of cell cycle regulators may induce cell division arrest and lead to smaller islets. The present data provide new insight into the role of the peroxisome in the development of the pancreas and may be valuable in furthering our understanding of the pathogenesis of IUGR-induced diabetes.

The brain development of infants with intrauterine growth restriction: role of glucocorticoids

Brain injury is a serious complication of intrauterine growth restriction (IUGR), but the exact mechanism remains unclear. While glucocorticoids (GCs) play an important role in intrauterine growth and development, GCs also have a damaging effect on microvascular endothelial cells. Moreover, intrauterine adverse environments lead to fetal growth restriction and the hypothalamus-pituitary-adrenal (HPA) axis resetting. In addition, chronic stress can cause a decrease in the number and volume of astrocytes in the hippocampus and glial cells play an important role in neuronal differentiation. Therefore, it is speculated that the effect of GCs on cerebral neurovascular units under chronic intrauterine stimulation is an important mechanism leading to brain injury in infants with growth restrictions.

Postnatal Nutrient Repartitioning due to Adaptive Developmental Programming

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.

Osteoprotegerin promotes islet β cell proliferation in intrauterine growth retardation rats through the PI3K/AKT/FoxO1 pathway

Osteoprotegerin (OPG) is a critical factor involved in bone metabolism. The level of OPG is increased in the serum of diabetic patients; however, there is no consensus in prior studies on the role of OPG in regulating the function of islet β cells. A rat model of intrauterine growth retardation (IUGR) was established in the present study to investigate whether OPG could enhance the proliferation of β cells; and an in vitro culture model of rat islet β cell line INS-1 was used, to confirm the effect of OPG supplementation and reveal the possible mechanism. The results showed that endogenous OPG expression was reduced and normal proliferation of β cells was impaired in the IUGR islets. Exogenous supplement of OPG restored β cell proliferation to an extent in the IUGR rats, possibly associated with regulation of the PI3K/AKT/FoxO1 signalling, as evidenced by the changes of protein expression in the pathway. Furthermore, treating rat islet INS-1 cells with a PI3K inhibitor, LY294002, blunted the effects of OPG supplement in promoting cell cycle and suppressing cell apoptosis. Taken together, the present work demonstrated that OPG supplementation could improve the proliferation of islet β cells in IUGR, and the PI3K/AKT/FoxO1 pathway is involved in the underlying mechanism.

Amino acid restriction increases β-cell death under challenging conditions

Malnutrition programs metabolism, favor dysfunction of β cells. We aimed to establish an in vitro protocol of malnutrition, assessing the effect of amino acid restriction upon the β cells. Insulin-producing cells INS-1E and pancreatic islets were maintained in RPMI 1640 medium containing 1× (Ctl) or 0.25× (AaR) of amino acids. We evaluated several markers of β-cell function and viability. AaR Insulin secretion was reduced, whereas cell viability was unaltered. Calcium oscillations in response to glucose increased in AaR. AaR showed lower Ins1 RNAm, snap 25, and PKC (protein kinase C) protein content, whereas phospho-eIF2α was increased. AaR cells exposed to nutrient or chemical challenges displayed higher apoptosis rates. We showed that amino acid restriction programmed β cell and induced functional changes. This model might be useful for the study of molecular mechanisms involved with β-cell programming helping to establish novel therapeutic targets to prevent harmful outcomes of malnutrition.

Children Born Small for Gestational Age: Differential Diagnosis, Molecular Genetic Evaluation, and Implications

Children born small for gestational age (SGA), defined as a birth weight and/or length below -2 SD score (SDS), comprise a heterogeneous group. The causes of SGA are multifactorial and include maternal lifestyle and obstetric factors, placental dysfunction, and numerous fetal (epi)genetic abnormalities. Short-term consequences of SGA include increased risks of hypothermia, polycythemia, and hypoglycemia. Although most SGA infants show catch-up growth by 2 years of age, ∼10% remain short. Short children born SGA are amenable to GH treatment, which increases their adult height by on average 1.25 SD. Add-on treatment with a gonadotropin-releasing hormone agonist may be considered in early pubertal children with an expected adult height below -2.5 SDS. A small birth size increases the risk of later neurodevelopmental problems and cardiometabolic diseases. GH treatment does not pose an additional risk.