Effects of periconceptional maternal alcohol intake and a postnatal high-fat diet on obesity and liver disease in male and female rat offspring

Intrauterine developmental origin, programming mechanism, and prevention strategy of fetal-originated hypercholesterolemia

There is increasing evidence that hypercholesterolemia has an intrauterine developmental origin. However, the pathogenesis of fetal-originated is still lacking in a theoretical system, which makes its clinical early prevention and treatment difficult. It has been found that an adverse environment during pregnancy (e.g., xenobiotic exposure) may lead to changes in fetal blood cholesterol levels through changing maternal cholesterol metabolic function and/or placental cholesterol transport function and may also directly affect the liver cholesterol metabolic function of the offspring in utero and continue after birth. Adverse environmental conditions during pregnancy may also raise maternal glucocorticoid levels and promote the placental glucocorticoid barrier opening, leading to fetal overexposure to maternal glucocorticoids. Intrauterine high-glucocorticoid exposure can alter the liver cholesterol metabolism of offspring, resulting in an increased susceptibility to hypercholesterolemia after birth. Abnormal epigenetic modifications are involved in the intrauterine programming mechanism of fetal-originated hypercholesterolemia. Some interventions targeted at pregnant mothers or offspring in early life have been proposed to effectively prevent and treat the development of fetal-originated hypercholesterolemia. In this paper, the recent research progress on fetal-originated hypercholesterolemia was reviewed, with emphasis on intrauterine maternal glucocorticoid programming mechanisms, in order to provide a theoretical basis for its early clinical warning, prevention, and treatment.

The Impacts of Periconceptional Alcohol on Neonatal Ovaries and Subsequent Adult Fertility in the Rat

Maternal exposures during pregnancy can impact the establishment of the ovarian reserve in offspring, the lifetime supply of germ cells that determine a woman's reproductive lifespan. However, despite alcohol consumption being common in women of reproductive age, the impact of prenatal alcohol on ovarian development is rarely investigated. This study used an established rat model of periconceptional ethanol exposure (PCEtOH; 12.5% v/v ethanol) for 4 days prior to 4 days post-conception. Ovaries were collected from neonates (day 3 and day 10), and genes with protein products involved in regulating the ovarian reserve analyzed by qPCR. Adult offspring had estrous cycles monitored and breeding performance assessed. PCEtOH resulted in subtle changes in expression of genes regulating apoptosis at postnatal day (PN) 3, whilst those involved in regulating growth and recruitment of primordial follicles were dysregulated at PN10 in neonatal ovaries. Despite these gene expression changes, there were no significant impacts on breeding performance in adulthood, nor on F2-generation growth or survival. This contributes additional evidence to suggest that a moderate level of alcohol consumption exclusively around conception, when a woman is often unaware of her pregnancy, does not substantially impact the fertility of her female offspring.

Exploring behavioral phenotypes in a mouse model of fetal alcohol spectrum disorders

Fetal alcohol spectrum disorders are one of the leading causes of developmental abnormalities worldwide. Maternal consumption of alcohol during pregnancy leads to a diverse range of cognitive and neurobehavioral deficits. Although moderate-to-heavy levels of prenatal alcohol exposure (PAE) have been associated with adverse offspring outcomes, there is limited data on the consequences of chronic low-level PAE. Here, we use a model of maternal voluntary alcohol consumption throughout gestation in a mouse model to investigate the effects of PAE on behavioral phenotypes during late adolescence and early adulthood in male and female offspring. Body composition was measured by dual-energy X-ray absorptiometry. Baseline behaviors, including feeding, drinking, and movement, were examined by performing home cage monitoring studies. The impact of PAE on motor function, motor skill learning, hyperactivity, acoustic reactivity, and sensorimotor gating was investigated by performing a battery of behavioral tests. PAE was found to be associated with altered body composition. No differences in overall movement, food, or water consumption were observed between control and PAE mice. Although PAE offspring of both sexes exhibited deficits in motor skill learning, no differences were observed in basic motor skills such as grip strength and motor coordination. PAE females exhibited a hyperactive phenotype in a novel environment. PAE mice exhibited increased reactivity to acoustic stimuli, and PAE females showed disrupted short-term habituation. Sensorimotor gating was not altered in PAE mice. Collectively, our data show that chronic low-level exposure to alcohol in utero results in behavioral impairments.

Prenatal alcohol exposure causes persistent microglial activation and age- and sex- specific effects on cognition and metabolic outcomes in an Alzheimer's Disease mouse model

Background: Prenatal alcohol exposure (PAE) causes behavioral deficits and increases risk of metabolic diseases. Alzheimer's Disease (AD) is a neurodegenerative disease that has a higher risk in adults with metabolic diseases. Both present with persistent neuroinflammation.Objectives: We tested whether PAE exacerbates AD-related cognitive decline in a mouse model (3xTg-AD; presenilin/amyloid precursor protein/tau), and assessed associations among cognition, metabolic impairment, and microglial reactivity.Methods: Alcohol-exposed (ALC) pregnant 3xTg-AD mice received 3 g/kg alcohol from embryonic day 8.5-17.5. We evaluated recognition memory and associative memory (fear conditioning) in 8-10 males and females per group at 3 months of age (3mo), 7mo, and 11mo, then assessed glucose tolerance, body composition, and hippocampal microglial activation at 12mo.Results: ALC females had higher body weights than controls from 5mo (p < .0001). Controls showed improved recognition memory at 11mo compared with 3mo (p = .007); this was not seen in ALC mice. Older animals froze more during fear conditioning than younger, and ALC mice were hyper-responsive to the fear-related cue (p = .017). Fasting blood glucose was lower in ALC males and higher in ALC females than controls. Positive associations occurred between glucose and fear-related context (p = .04) and adiposity and fear-related cue (p = .0002) in ALC animals. Hippocampal microglial activation was higher in ALC than controls (p < .0001); this trended to correlate with recognition memory.Conclusions: ALC animals showed age-related cognitive impairments that did not interact with AD risk but did correlate with metabolic dysfunction and somewhat with microglial activation. Thus, metabolic disorders may be a therapeutic target for people with FASDs.

Periconceptional alcohol alters in vivo heart function in ageing female rat offspring: Possible involvement of oestrogen receptor signalling

NEW FINDINGS

What is the central question of this study? What are the cardiovascular consequences of periconceptual ethanol on offspring throughout the lifespan? What is the main finding and its importance? It is shown for the first time that periconceptional alcohol has sex-specific effects on heart growth, with ageing female offspring exhibiting decreased cardiac output. Altered in vivo cardiac function in ageing female offspring may be linked to changes in cardiac oestrogen receptor expression.

ABSTRACT

Alcohol exposure throughout gestation is detrimental to cardiac development and function. Although many women decrease alcohol consumption once aware of a pregnancy, exposure prior to recognition is common. We, therefore, examined the effects of periconceptional alcohol exposure (PC:EtOH) on heart function, and explored mechanisms that may contribute. Female Sprague-Dawley rats received a liquid diet ±12.5% v/v ethanol from 4 days prior to mating until 4 days after mating (PC:EtOH). Cardiac function was assessed via echocardiography, and offspring were culled at multiple time points for assessment of morphometry, isolated heart and aortic ring function, protein and transcriptional changes. PC:EtOH-exposed embryonic day 20 fetuses (but not postnatal offspring) had larger hearts relative to body weight. Ex vivo analysis of hearts at 5-7 months old (mo) indicated no changes in coronary function or cardiac ischaemic tolerance, and apparently improved ventricular compliance in PC:EtOH females (compared to controls). At 12 mo, vascular responses in isolated aortic rings were unaltered by PC:EtOH, whilst echocardiography revealed reduced cardiac output in female but not male PC:EtOH offspring. At 19 mo, left ventricular transcript and protein for type 1 oestrogen receptor (ESR1), HSP90 transcript and plasma oestradiol levels were all elevated in female PC:EtOH exposed offspring. Summarising, PC:EtOH adversely impacts in vivo heart function in mature female offspring, associated with increased ventricular oestrogen-related genes. PC:EtOH may thus influence age-related heart dysfunction in females through modulation of oestrogen signalling.

Fetal alcohol spectrum disorders

Alcohol readily crosses the placenta and may disrupt fetal development. Harm from prenatal alcohol exposure (PAE) is determined by the dose, pattern, timing and duration of exposure, fetal and maternal genetics, maternal nutrition, concurrent substance use, and epigenetic responses. A safe dose of alcohol use during pregnancy has not been established. PAE can cause fetal alcohol spectrum disorders (FASD), which are characterized by neurodevelopmental impairment with or without facial dysmorphology, congenital anomalies and poor growth. FASD are a leading preventable cause of birth defects and developmental disability. The prevalence of FASD in 76 countries is >1% and is high in individuals living in out-of-home care or engaged in justice and mental health systems. The social and economic effects of FASD are profound, but the diagnosis is often missed or delayed and receives little public recognition. Future research should be informed by people living with FASD and be guided by cultural context, seek consensus on diagnostic criteria and evidence-based treatments, and describe the pathophysiology and lifelong effects of FASD. Imperatives include reducing stigma, equitable access to services, improved quality of life for people with FASD and FASD prevention in future generations.

Altered bone and body composition in children and adolescents with confirmed prenatal alcohol exposure

Prenatal alcohol exposure can contribute to long term adverse health outcomes. Development of the skeletal system begins at the early embryonic stage and continues into early adulthood but the effect of prenatal alcohol exposure on skeletal growth is relatively unexplored in a clinical population. Here, we performed dual X-ray absorptiometry to examine bone, fat, and muscle accrual in children and adolescents diagnosed with, or at risk of, fetal alcohol spectrum disorders (FASDs). Children (aged 4-9 years) with FASD or at risk of FASD (n = 10) had similar growth to age matched controls (n = 27). By adolescence (aged ≥10 years), those with FASDs (n = 13) were shorter and had lower areal bone mineral density and lean tissue mass than typically developing peers (n = 29). Overall, adolescents diagnosed with FASDs had greater odds of impairments to bone and body composition. These findings highlight the importance of early FASD diagnosis and appropriate post-diagnostic medical follow-up to enable timely, effective interventions to optimize bone and body composition during paediatric growth.

Orally administered zingerone does not mitigate alcohol-induced hepatic oxidative stress in growing Sprague Dawley rat pups

Neonatal alcohol exposure (NAE) can induce oxidative stress. We determined whether zingerone (ZO), a phytochemical with anti-oxidant activity, can mitigate the negative impact of neonatal alcohol-induced oxidative stress. Seventy ten-day-old Sprague-Dawley rat pups (35 male, 35 female) were randomly assigned and administered the following treatment regimens daily from postnatal day (PND) 12-21: group 1 - nutritive milk (NM), group 2 - NM +1 g/kg ethanol (Eth), group 3 - NM + 40 mg/kg ZO, group 4 - NM + Eth + ZO. Growth performance, blood glucose and plasma triglycerides (TGs), total cholesterol, HDL-cholesterol, leptin and insulin concentration were determined. Cytochrome p450E21(CYP2E1) and thiobarbituric acid (TBARS); markers of hepatic oxidative stress and catalase, superoxide dismutase (SOD) and total glutathione (GSH), anti-oxidant markers of the pups were determined. Oral administration of ethanol (NM + Eth), zingerone (NM + ZO) and combined ethanol and zingerone (NM + Eth + ZO) did not affect the growth performance and insulin and leptin concentration of the rats (p > 0.05). Ethanol significantly reduced plasma TGs concentration of female rats (p = 0.04 vs control). However, ethanol and/or its combination with zingerone decreased hepatic GSH (p = 0.02 vs control) and increased CYP2E1 (p = 0.0002 vs control) activity in male rat pups. Zingerone had no effect (p > 0.05 vs control) on the rats' CYP2E1, GSH, SOD and catalase activities. Neonatal alcohol administration elicited hepatic oxidative stress in male rat pups only, showing sexual dimorphism. Zingerone (NM + ZO) prevented an increase in CYP2E1 activity and a decrease in GSH concentration but did not prevent the alcohol-induced hepatic oxidative stress in the male rat pups.

Associations of maternal periconceptional alcohol consumption with offspring prehypertension/hypertension at age 6 years: the Growing Up in Singapore Towards healthy Outcomes prospective mother-offspring cohort study

OBJECTIVE

To evaluate the relationship of the levels of maternal alcohol consumption during the 1 year before pregnancy recognition with childhood cardiorenal, metabolic, and neurocognitive health.

METHODS

In 1106 women and their children from the Growing Up in Singapore Towards healthy Outcomes mother-offspring cohort, quantity of maternal alcohol consumption in the 12 months prior to pregnancy recognition was categorized as high (≥75th percentile: 1.9 g/day), low (<1.9 g/day), and none, and frequency of alcohol consumption was categorized as high (≥2-3 times/week), low (<2-3 times/week), and none. Offspring MRI-based abdominal fat depot, kidney, and brain volumes, blood pressure, metabolic syndrome score, and cognitive intelligence scores were assessed. Child prehypertension/hypertension at age 6 years was defined using a simplified pediatric threshold of 110/70 mmHg.

RESULTS

The average maternal alcohol consumption in the year prior to pregnancy recognition was 2.5 g/day, which is lower than the daily maximal limit of one standard drink (10 g) recommended for women by Singapore's Ministry of Health. After adjusting for participant characteristics, alcohol consumption at least 1.9 g/day was associated with over two-fold higher risk (risk ratio = 2.18, P = 0.013) of child prehypertension and 15% greater kidney growth between early infancy and age 6 years (P = 0.040) compared with abstinence. Alcohol consumption was not associated with metabolic and neurocognitive health at age 6-7 years. The associations with high frequency of alcohol consumption were concordant with those obtained for quantity of alcohol consumption.

CONCLUSION

Maternal self-reported alcohol consumption at least 1.9 g/day prior to pregnancy recognition was associated with increased risk of child prehypertension and rapid kidney growth. Our findings highlight the potential detrimental effects of low periconceptional alcohol consumption, below national guidelines on offspring cardiorenal health.

Aging-Related Behavioral, Adiposity, and Glucose Impairments and Their Association following Prenatal Alcohol Exposure in the C57BL/6J Mouse

People that experience prenatal alcohol exposure (PAE) may have behavioral and metabolic impairments, and it is unclear whether these remain stable or change with age. We assessed behavioral and metabolic endpoints across the lifespan in a mouse model of fetal alcohol spectrum disorder (FASD). Pregnant C57BL/6J mice received alcohol (ALC; 3 g/kg) or maltose-dextrin (control, CON) daily from embryonic day 8.5 to 17.5. Offspring were tested on accelerating rotarod, Y-maze, novel object recognition, and fear conditioning at 6 weeks and 10 and 17 months; females were also tested at 24 months. Body composition, fasting glucose, and glucose clearance were assessed at 18 months. Female but not male ALC mice had greater adiposity than age-matched CON from 7 months onward. At 18 months, male but not female ALC mice had reduced glucose clearance and ALC mice were more likely to have elevated fasting glucose. In the rotarod training session, ALC females performed worse than CON. In the Y-maze, significant exposure-age interactions affected ALC performance in both sexes versus age-match CON. For fear conditioning, all animals acquired the task and froze more at older ages. In both the context and cued tasks, there were exposure-age interactions and ALC animals frozen less than CON at 10 months. Correlation analysis revealed that fasting glucose and glucose clearance correlated with % of body fat in ALC but not in CON mice. Additionally, glucose intolerance and % body fat negatively correlated with performance in the rotarod, context learning, and novel object recognition tasks in ALC but not CON mice. All mice exhibit worsening of behavioral performance as they age, and PAE did not further exacerbate this. ALC but not CON mice displayed adiposity and glucose intolerance that correlate with their cognitive impairments, suggesting that these may be mechanistically related in PAE. Findings emphasize that FASD should be considered a whole-body disorder.

Prenatal choline supplementation during mouse pregnancy has differential effects in alcohol-exposed fetal organs

BACKGROUND

Fetal alcohol spectrum disorders (FASD) are preventable adverse outcomes consequent to prenatal alcohol exposure. Supplemental choline confers neuroprotection to the alcohol-exposed offspring, but its actions outside the brain are unclear. We previously reported that prenatal exposure of mice to 4.5 g/kg of alcohol decreased placental weight in females only, but decreased body weight and liver-to-body weight ratio and increased brain-to-body weight ratio in both sexes. Here we test the hypotheses that a lower alcohol dose will elicit similar outcomes, and that concurrent choline treatment will mitigate these outcomes.

METHODS

Pregnant C57BL/6J mice were gavaged with alcohol (3 g/kg; Alc) or maltodextrin (MD) from embryonic day (E) 8.5-17.5. Some also received a subcutaneous injection of 100 mg/kg choline chloride (Alc + Cho, MD + Cho). Outcomes were evaluated on E17.5.

RESULTS

Alc dams had lower gestational weight gain than MD; this was normalized by choline. In males, Alc decreased placental weight whereas choline increased placental efficiency, and Alc + Cho (vs. MD) tended to further reduce placental weight and increase efficiency. Despite no significant alcohol effects on these measures, choline increased fetal body weight but not brain weight, thus reducing brain-to-body weight ratio in both sexes. This ratio was also lower in the Alc + Cho (vs. MD) fetuses. Alc reduced liver weight and the liver-to-body weight ratio; choline did not improve these. Placental weight and efficiency correlated with litter size, whereas placental efficiency correlated with fetal morphometric measurements.

CONCLUSIONS

Choline prevents an alcohol-induced reduction in gestational weight gain and fetal body weight and corrects fetal brain sparing, consistent with clinical findings of improvements in alcohol-exposed children born to mothers receiving choline supplementation. Importantly, we show that choline enhances placental efficiency in the alcohol-exposed offspring but does not normalize fetal liver growth. Our findings support choline supplementation during pregnancy to mitigate the severity of FASD and emphasize the need to examine choline's actions in different organ systems.

Maternal choline supplementation in a rat model of periconceptional alcohol exposure: Impacts on the fetus and placenta

BACKGROUND

Maternal choline supplementation in rats can ameliorate specific neurological and behavioral abnormalities caused by alcohol exposure during pregnancy. We tested whether choline supplementation ameliorates fetal growth restriction and molecular changes in the placenta associated with periconceptional ethanol exposure (PCE) in the rat.

METHODS

Sprague Dawley dams were given either 12.5% ethanol (PCE) or 0% ethanol (Con) in a liquid diet from 4 days prior to 4 days after conception. At day 5 of pregnancy, dams were either placed on a standard chow (1.6 g choline/kg chow) or an intermediate chow (2.6 g choline/kg chow). On day 10 of pregnancy, a subset of the intermediate dams were placed on a chow further supplemented with choline (7.2 g choline/kg chow), resulting in 6 groups. Fetuses and placentas were collected on day 20 of pregnancy for analysis.

RESULTS

Choline supplementation resulted in increased fetal weight at late gestation, ameliorating the deficits due to PCE. This was most pronounced in litters on a standard chow during pregnancy. Choline also increased fetal liver weight and decreased fetal brain:liver ratio, independent of alcohol exposure. Placental weight was reduced as choline levels in the chow increased, particularly in female placentas. This resulted in a greater ratio of fetal:placental weight, suggesting increased placental efficiency. Global DNA methylation in the placenta was altered in a sex-specific manner by both PCE and choline. However, the increased glycogen deposition in female placentas, previously reported in this PCE model, was not prevented by choline supplementation.

CONCLUSIONS

Our results suggest that choline has the potential to ameliorate fetal growth restriction associated with PCE and improve placental efficiency following prenatal alcohol exposure. Our study highlights the importance of maternal nutrition in moderating the severity of adverse fetal and placental outcomes that may arise from prenatal alcohol exposure around the time of conception.

Fetal Programming Is Deeply Related to Maternal Selenium Status and Oxidative Balance; Experimental Offspring Health Repercussions

Nutrients consumed by mothers during pregnancy and lactation can exert permanent effects upon infant developing tissues, which could represent an important risk factor for diseases during adulthood. One of the important nutrients that contributes to regulating the cell cycle and tissue development and functionality is the trace element selenium (Se). Maternal Se requirements increase during gestation and lactation. Se performs its biological action by forming part of 25 selenoproteins, most of which have antioxidant properties, such as glutathione peroxidases (GPxs) and selenoprotein P (SELENOP). These are also related to endocrine regulation, appetite, growth and energy homeostasis. In experimental studies, it has been found that low dietary maternal Se supply leads to an important oxidative disruption in dams and in their progeny. This oxidative stress deeply affects gestational parameters, and leads to intrauterine growth retardation and abnormal development of tissues, which is related to endocrine metabolic imbalance. Childhood pathologies related to oxidative stress during pregnancy and/or lactation, leading to metabolic programing disorders like fetal alcohol spectrum disorders (FASD), have been associated with a low maternal Se status and intrauterine growth retardation. In this context, Se supplementation therapy to alcoholic dams avoids growth retardation, hepatic oxidation and improves gestational and breastfeeding parameters in FASD pups. This review is focused on the important role that Se plays during intrauterine and breastfeeding development, in order to highlight it as a marker and/or a nutritional strategy to avoid diverse fetal programming disorders related to oxidative stress.

Intergenerational implications of alcohol intake: metabolic disorders in alcohol-naïve rat offspring

Alcohol drinking may be associated with an increased risk of various metabolic diseases. Rat lines selectively bred for alcohol preference and alcohol avoidance constitute an interesting model to study inherited factors related to alcohol drinking and metabolic disorders. The aim of the present study was to compare the levels of selected laboratory biomarkers of metabolic disorders in blood samples from naïve offspring of Warsaw alcohol high-preferring (WHP), Warsaw alcohol low-preferring (WLP), and wild Wistar rats. Blood samples were collected from 3-month old (300–350 g) alcohol-naïve, male offspring of WHP (n = 8) and WLP rats (n = 8), as well as alcohol-naïve, male, wild Wistar rats. Markers of metabolic, hepatic, and pancreatic disorders were analysed (levels of homocysteine, glucose, total cholesterol, triglycerides and γ-glutamyl transferase (GGT), aspartate (AST), alanine aminotransferase (ALT), and amylase serum activities). Alcohol-naïve offspring of WHP, WLP, and wild Wistar rats differed significantly in the levels of triglycerides, total cholesterol, homocysteine, as well as in the activity of GGT, ALT, AST, and amylase enzymes. Most markers in the alcohol-naïve offspring of WHP rats were altered even thought they were never exposed to alcohol pre- or postnatally. This may suggest that parental alcohol abuse can have a detrimental influence on offspring vulnerability to metabolic disorders.

Hempseed (Cannabis sativa) lipid fractions alleviate high-fat diet-induced fatty liver disease through regulation of inflammation and oxidative stress

Diet and lifestyle-induced dysregulated lipid metabolism have been implicated in fatty liver disease. Chronic redox modulation and hepatic inflammation are key pathological mediators and hallmarks of fatty liver disease associated liver steatosis and steatohepatitis. In this context, owing to the beneficial phytochemical properties such as optimal omega-6: omega-3 PUFA ratio of hempseed, we aimed to explore its potential anti-inflammatory and antioxidant properties against high-fat diet (HFD)-induced experimental model of fatty liver disease. The hempseed lipid fractions (HEMP) were prepared and their ameliorating effects on HFD induced morphological changes, lipid profiles, liver function markers (LFT), markers of oxidative stress and inflammation were studied. Results indicated that HEMP administration to hypercholesterolemic rats resolved the morphological, histopathological, and biochemical indicators of fatty liver diseases. Further, the mechanistic evidence revealed that these hepatoprotective effects of HEMP are mediated through inhibition of oxidative stress and inflammatory mediators such as Cox-2, hPGDS, mPGES, IL-4, TNF-α and sEH. In conclusion, current study suggests the plausible antioxidant and anti-inflammatory role of HEMP in alleviating pathophysiological conditions including fatty liver disease, where oxidative stress and inflammation are key mediators.

Fetal alcohol spectrum disorder predisposes to metabolic abnormalities in adulthood

Prenatal alcohol exposure (PAE) affects at least 10% of newborns globally and leads to the development of fetal alcohol spectrum disorders (FASDs). Despite its high incidence, there is no consensus on the implications of PAE on metabolic disease risk in adults. Here, we describe a cohort of adults with FASDs that had an increased incidence of metabolic abnormalities, including type 2 diabetes, low HDL, high triglycerides, and female-specific overweight and obesity. Using a zebrafish model for PAE, we performed population studies to elucidate the metabolic disease seen in the clinical cohort. Embryonic alcohol exposure (EAE) in male zebrafish increased the propensity for diet-induced obesity and fasting hyperglycemia in adulthood. We identified several consequences of EAE that may contribute to these phenotypes, including a reduction in adult locomotor activity, alterations in visceral adipose tissue and hepatic development, and persistent diet-responsive transcriptional changes. Taken together, our findings define metabolic vulnerabilities due to EAE and provide evidence that behavioral changes and primary organ dysfunction contribute to resultant metabolic abnormalities.

Prenatal alcohol exposure programmes offspring disease: insulin resistance in adult males in a rat model of acute exposure

KEY POINTS

Prenatal alcohol exposure has the potential to affect fetal development and programme chronic disease in offspring. Previous preclinical models typically use high, chronic doses of alcohol throughout pregnancy to examine effects on offspring, particularly on the brain and behaviour. In this study we use a rat model of moderate, acute, prenatal alcohol exposure to determine if this can be detrimental to maintenance of glucose homeostasis in adolescent and adult offspring. Although female offspring were relatively unaffected, there was evidence of insulin resistance in 6-month-old male offspring exposed to prenatal alcohol, suggestive of a pre-diabetic state. This result suggests that even a relatively low-dose, acute exposure to alcohol during pregnancy can still programme metabolic dysfunction in a sex-specific manner.

ABSTRACT

Alcohol consumption is highly prevalent amongst women of reproductive age. Given that approximately 50% of pregnancies are unplanned, alcohol has the potential to affect fetal development and programme chronic disease in offspring. We examined the effect of an acute but moderate prenatal alcohol exposure (PAE) on glucose metabolism, lipid levels and dietary preference in adolescent and/or adult rat offspring. Pregnant Sprague-Dawley rats received an oral gavage of ethanol (1 g kg^-1 maternal body weight, n = 9 dams) or an equivalent volume of saline (control, n = 8 dams) at embryonic days 13.5 and 14.5. PAE resulted in a blood alcohol concentration of 0.05-0.06% 1 h post-gavage in dams. Fasting blood glucose concentration was not affected by PAE in offspring at any age, nor were blood glucose levels during a glucose tolerance test (GTT) in 6-month-old offspring (P > 0.5). However, there was evidence of insulin resistance in PAE male offspring at 6 months of age, with significantly elevated fasting plasma insulin (P = 0.001), a tendency for increased first phase insulin secretion during the GTT and impaired glucose clearance following an insulin challenge (P = 0.007). This was accompanied by modest alterations in protein kinase B (AKT) signalling in adipose tissue. PAE also resulted in reduced calorie consumption by offspring compared to controls (P = 0.04). These data suggest that a relatively low-level, acute PAE programmes metabolic dysfunction in offspring in a sex-specific manner. These results highlight that alcohol consumption during pregnancy has the potential to affect the long-term health of offspring.

Periconceptional ethanol exposure induces a sex specific diuresis and increase in AQP2 and AVPR2 in the kidneys of aged rat offspring

Maternal alcohol consumption can impair renal development and program kidney dysfunction in offspring. Given that most women who drink alcohol cease consumption upon pregnancy recognition, we aimed to investigate the effect of alcohol around the time of conception (PC:EtOH) on offspring renal development and function. Rats received a liquid diet ±12.5% v/v ethanol from 4 days before to 4 days after mating. At postnatal day 30, nephron number was assessed. Urine flow and electrolyte (Na, K, Cl) excretion was measured at 6 and 19 months and blood pressure at 12 months. At 19 months, kidneys were collected for gene and protein analysis and assessment of collecting duct length. At postnatal day 30, PC:EtOH offspring had fewer nephrons. At 6 months, PC:EtOH exposure did not alter urine flow nor affect blood pressure at 12 months. At 19 months, female but not male offspring exposed to PC:EtOH drank more water and had a higher urine flow despite no differences in plasma arginine vasopressin (AVP) concentrations. Aqp2 mRNA and Avpr2 mRNA and protein expression was increased in kidneys from female PC:EtOH offspring but collecting duct lengths were similar. Immunofluorescent staining revealed diffuse cytoplasmic distribution of AQP2 protein in kidneys from PC:EtOH females, compared with controls with apical AQP2 localization. PC:EtOH resulted in a low nephron endowment and in female offspring, associated with age-related diuresis. Changes in expression and cellular localization of AQP2 likely underpin this disturbance in water homeostasis and highlight the need for alcohol to be avoided in early pregnancy.

Periconceptional environment and the developmental origins of disease

The concept emerging from Professor David Barker’s seminal research on the developmental origins of later-life disease has progressed in many directions since it was first published. One critical question being when during gestation might environment alter the developmental programme with such enduring consequences. Here, we review the growing consensus from clinical and animal research that the period around conception, embracing gamete maturation and early embryogenesis might be the most vulnerable period. We focus on four types of environmental exposure shown to modify periconceptional reproduction and offspring development and health: maternal overnutrition and obesity; maternal undernutrition; paternal diet and health; and assisted reproductive technology. These conditions may act through diverse epigenetic, cellular and physiological mechanisms to alter gene expression and cellular signalling and function in the conceptus affecting offspring growth and metabolism leading to increased risk for cardiometabolic and neurological disease in later life.

Preconception paternal alcohol exposure exerts sex-specific effects on offspring growth and long-term metabolic programming

BACKGROUND

Although clinical data support an association between paternal alcohol use and deficits in child neurocognitive development, the relationship between paternal drinking and alcohol-induced growth phenotypes remains challenging to define. Using an established mouse model of chronic exposure, previous work by our group has linked preconception paternal alcohol use to sex-specific patterns of fetal growth restriction and placental dysfunction. The aim of the present study was to investigate the long-term impact of chronic preconception paternal alcohol use on offspring growth and metabolic programming.

RESULTS

Preconception paternal alcohol exposure induced a prolonged period of fetal gestation and an increased incidence of intrauterine growth restriction, which affected the male offspring to a greater extent than the females. While the female offspring of ethanol-exposed males were able to match the body weights of the controls within the first 2 weeks of postnatal life, male offspring continued to display an 11% reduction in weight at 5 weeks of age and a 6% reduction at 8 weeks of age. The observed growth deficits associated with insulin hypersensitivity in the male offspring, while in contrast, females displayed a modest lag in their glucose tolerance test. These metabolic defects were associated with an up-regulation of genes within the pro-fibrotic TGF-β signaling pathway and increased levels of cellular hydroxyproline within the livers of the male offspring. We observed suppressed cytokine profiles within the liver and pancreas of both the male and female offspring, which correlated with the up-regulation of genes in the LiverX/RetinoidX/FarnesoidX receptor pathways. However, patterns of gene expression were highly variable between the offspring of alcohol-exposed sires. In the adult offspring of alcohol-exposed males, we did not observe any differences in the allelic expression of Igf2 or any other imprinted genes.

CONCLUSIONS

The impact of paternal alcohol use on child development is poorly explored and represents a significant gap in our understanding of the teratogenic effects of ethanol. Our studies implicate paternal exposure history as an additional and important modifier of alcohol-induced growth phenotypes and challenge the current maternal-centric exposure paradigm.

Effect of Choline Supplementation on Neurological, Cognitive, and Behavioral Outcomes in Offspring Arising from Alcohol Exposure During Development: A Quantitative Systematic Review of Clinical and Preclinical Studies

Prenatal alcohol exposure results in cognitive, behavioral, and neurological deficits in offspring. There is an urgent need for safe and effective treatments to overcome these effects. Maternal choline supplementation has been identified as a potential intervention. Our objective was to review preclinical and clinical studies using choline supplementation in known cases of fetal alcohol exposure to determine its effectiveness in ameliorating deficits in offspring. A systematic search of 6 electronic databases was conducted and studies selected by reviewing titles/abstracts against specific inclusion/exclusion criteria. Study characteristics, population demographics, alcohol exposure, and intervention methods were tabulated, and quality of reporting was assessed. Data on cognitive, behavioral, and neurological outcomes were extracted and tabulated. Quantitative analysis was performed to determine treatment effects for individual study outcomes. A total of 189 studies were retrieved following duplicate removal. Of these, 22 studies (2 randomized controlled trials, 2 prospective cohort studies, and 18 preclinical studies) met the full inclusion/exclusion criteria. Choline interventions were administered at different times relative to alcohol exposure, impacting on their success to prevent deficits for specific outcomes. Only 1 clinical study showed significant improvements in information processing in 6-month-old infants from mothers treated with choline during pregnancy. Preclinical studies showed significant amelioration of deficits due to prenatal alcohol exposure across a wide variety of outcomes, including epigenetic/molecular changes, gross motor, memory, and executive function. This review suggests that choline supplementation has the potential to ameliorate specific behavioral, neurological, and cognitive deficits in offspring caused by fetal alcohol exposure, at least in preclinical studies. As only 1 clinical study has shown benefit, we recommend more clinical trials be undertaken to assess the effectiveness of choline in preventing deficits across a wider range of cognitive domains in children.

Does prenatal alcohol exposure cause a metabolic syndrome? (Non-)evidence from a mouse model of fetal alcohol spectrum disorder

Although prenatal alcohol exposure (PAE) reduces offspring growth, it may increase obesity risk at adolescence. Animal models of PAE display glucose intolerance and increased adiposity, suggesting that PAE causes metabolic reprogramming. We tested this hypothesis in a mouse model of binge PAE, wherein pregnant C57Bl/6J females received 3 g/kg alcohol (ETOH) daily from gestational day 12.5 to 17.5; maltodextrin (MD) and medium chain triglycerides (MCT) served as isocaloric nutritional controls, and sham (H2O) treatment controlled for gavage stress. Our comprehensive assessment quantified body composition, energy expenditure, glucose tolerance, and cardiovascular function in offspring at age 17 weeks. Although ETOH pups were initially lighter than all other groups, they did not have a unique obesogenic phenotype. Instead, a similar obesogenic phenotype emerged in all three caloric groups (MCT, MD, ETOH), such that caloric groups had greater post-weaning weight gain (both sexes), reduced gonadal fat weight (males), and reduced glucose clearance (males) compared against H2O offspring. PAE did not affect body composition, respiratory exchange ratio, metabolic adaption to high-fat or low-fat diet, eating behavior, and blood pressure, and ETOH values did not differ from those obtained from isocaloric controls. Exposure to a higher alcohol dose (4.5 g/kg) or a high-fat (60%) diet did not exacerbate differences in body composition or glucose tolerance. “PAE-specific” effects on postnatal growth, glucose tolerance, adiposity, or hypertension only emerged when PAE offspring were compared just against H2O controls, or against MD controls. We conclude that prior reports of obesity and glucose intolerance in adult PAE offspring reflect the contribution of added gestational calories, and not alcohol’s pharmacologic action. Results suggest that the increased adiposity risk in FASD is not caused by metabolic reprogramming, and instead originates from behavioral, medication, and/or dietary practices. This study highlights the importance of appropriate dietary controls in nutritional studies of PAE.