Maternal diet intervention before pregnancy primes offspring lipid metabolism in liver

Nutrigenetic and Epigenetic Mechanisms of Maternal Nutrition-Induced Glucolipid Metabolism Changes in the Offspring

Maternal nutrition during pregnancy regulates the offspring's metabolic homeostasis, including insulin sensitivity and the metabolism of glucose and lipids. The fetus undergoes a crucial period of plasticity in the uterus; metabolic changes in the fetus during pregnancy caused by maternal nutrition not only influence fetal growth and development but also have a long-term or even life-long impact for the offspring. Epigenetic modifications, such as DNA methylation, histone modification, and non-coding RNAs, play important roles in intergenerational and transgenerational effects. In this context, this narrative review comprehensively summarizes and analyzes the molecular mechanisms underlying how maternal nutrition, including a high-fat diet, polyunsaturated fatty acid diet, methyl donor nutrient supplementation, feed restriction, and protein restriction during pregnancy, impacts the genes involved in glucolipid metabolism in the liver, adipose tissue, hypothalamus, muscle, and oocytes of the offspring in terms of the epigenetic modifications. This will provide a foundation for the further exploration of nutrigenetic and epigenetic mechanisms for integrative mother-child nutrition and promotion of the offspring's health through the regulation of maternal nutrition during pregnancy. Note: This paper is part of the Nutrition Reviews Special Collection on Precision Nutrition.

Postnatal Consumption of Black Bean Powder Protects against Obesity and Dyslipidemia in Male Adult Rat Offspring from Obese Pregnancies

The adverse influence of maternal obesity on offspring metabolic health throughout the life-course is a significant public health challenge with few effective interventions. We examined if black bean powder (BBP) supplementation to a high-calorie maternal pregnancy diet or a postnatal offspring diet could offer protection against the metabolic programming of metabolic disease risk in adult offspring. Female Sprague Dawley rats were randomly assigned to one of three diets (n = 10/group) for a 3-week pre-pregnancy period and throughout gestation and lactation: (i) a low-caloric control diet (CON); (ii) a high-caloric obesity-inducing diet (HC); or (iii) the HC diet with 20% black bean powder (HC-BBP). At weaning [postnatal day (PND) 21], one male pup from each dam was weaned onto the CON diet throughout the postnatal period until adulthood (PND120). In addition, a second male from the HC group only was weaned onto the CON diet supplemented with BBP (CON-BBP). Thus, based on the maternal diet exposure and offspring postnatal diet, four experimental adult offspring groups were compared: CON/CON, HC/CON, HC-BPP/CON, and HC/CON-BBP. On PND120, blood was collected for biochemical analysis (e.g., lipids, glycemic control endpoints, etc.), and livers were excised for lipid analysis (triglycerides [TG] and cholesterol) and the mRNA/protein expression of lipid-regulatory targets. Compared with the CON/CON group, adult offspring from the HC/CON group exhibited a higher (p < 0.05) body weight (BW) (682.88 ± 10.67 vs. 628.02 ± 16.61 g) and hepatic TG (29.55 ± 1.31 vs. 22.86 ± 1.85 mmol/g). Although maternal BBP supplementation (HC-BBP/CON) had little influence on metabolic outcomes, the consumption of BBP in the postnatal period (HC/CON-BBP) lowered hepatic TG and cholesterol compared with the other treatment groups. Reduced hepatic TG in the HC/CON-BBP was likely associated with lower postnatal BW gain (vs. HC/CON), lower mRNA and protein expression of hepatic Fasn (vs. HC/CON), and lower serum leptin concentration (vs. CON/CON and HC groups). Our results suggest that the postnatal consumption of a black-bean-powder-supplemented diet may protect male rat offspring against the programming of obesity and dyslipidemia associated with maternal obesity. Future work should investigate the bioactive fraction of BBP responsible for the observed effect.

Preconception Diet Interventions in Obese Outbred Mice and the Impact on Female Offspring Metabolic Health and Oocyte Quality

Obese individuals often suffer from metabolic health disorders and reduced oocyte quality. Preconception diet interventions in obese outbred mice restore metabolic health and oocyte quality and mitochondrial ultrastructure. Also, studies in inbred mice have shown that maternal obesity induces metabolic alterations and reduces oocyte quality in offspring (F1). Until now, the effect of maternal high-fat diet on F1 metabolic health and oocyte quality and the potential beneficial effects of preconception dietary interventions have not been studied together in outbred mice. Therefore, we fed female mice a high-fat/high-sugar (HF/HS) diet for 7 weeks and switched them to a control (CONT) or caloric-restriction (CR) diet or maintained them on the HF/HS diet for 4 weeks before mating, resulting in three treatment groups: diet normalization (DN), CR, and HF/HS. In the fourth group, mice were fed CONT diet for 11 weeks (CONT). HF/HS mice were fed an HF/HS diet from conception until weaning, while all other groups were then fed a CONT diet. After weaning, offspring were kept on chow diet and sacrificed at 11 weeks. We observed significantly elevated serum insulin concentrations in female HF/HS offspring and a slightly increased percentage of mitochondrial ultrastructural abnormalities, mitochondrial size, and mitochondrial mean gray intensity in HF/HS F1 oocytes. Also, global DNA methylation was increased and cellular stress-related proteins were downregulated in HF/HS F1 oocytes. Mostly, these alterations were prevented in the DN group, while, in CR, this was only the case for a few parameters. In conclusion, this research has demonstrated for the first time that a maternal high-fat diet in outbred mice has a moderate impact on female F1 metabolic health and oocyte quality and that preconception DN is a better strategy to alleviate this compared to CR.

Gestational and Developmental Contributors of Pediatric MASLD

Pediatric metabolic dysfunction-associated steatotic liver disease (MASLD) is common and can be seen as early as in utero. A growing body of literature suggests that gestational and early life exposures modify the risk of MASLD development in children. These include maternal risk factors, such as poor cardiometabolic health (e.g., obesity, gestational diabetes, rapid weight gain during pregnancy, and MASLD), as well as periconceptional dietary exposures, degree of physical activity, intestinal microbiome, and smoking. Paternal factors, such as diet and obesity, also appear to play a role. Beyond gestation, early life dietary exposures, as well as the rate of infant weight gain, may further modify the risk of future MASLD development. The mechanisms linking parental health and environmental exposures to pediatric MASLD are complex and not entirely understood. In conclusion, investigating gestational and developmental contributors to MASLD is critical and may identify future interventional targets for disease prevention.

Inflammation and Oxidative Stress Induced by Obesity, Gestational Diabetes, and Preeclampsia in Pregnancy: Role of High-Density Lipoproteins as Vectors for Bioactive Compounds

Inflammation and oxidative stress are essential components in a myriad of pathogenic entities that lead to metabolic and chronic diseases. Moreover, inflammation in its different phases is necessary for the initiation and maintenance of a healthy pregnancy. Therefore, an equilibrium between a necessary/pathologic level of inflammation and oxidative stress during pregnancy is needed to avoid disease development. High-density lipoproteins (HDL) are important for a healthy pregnancy and a good neonatal outcome. Their role in fetal development during challenging situations is vital for maintaining the equilibrium. However, in certain conditions, such as obesity, diabetes, and other cardiovascular diseases, it has been observed that HDL loses its protective properties, becoming dysfunctional. Bioactive compounds have been widely studied as mediators of inflammation and oxidative stress in different diseases, but their mechanisms of action are still unknown. Nonetheless, these agents, which are obtained from functional foods, increase the concentration of HDL, TRC, and antioxidant activity. Therefore, this review first summarizes several mechanisms of HDL participation in the equilibrium between inflammation and oxidative stress. Second, it gives an insight into how HDL may act as a vector for bioactive compounds. Third, it describes the relationships between the inflammation process in pregnancy and HDL activity. Consequently, different databases were used, including MEDLINE, PubMed, and Scopus, where scientific articles published in the English language up to 2023 were identified.

Maternal Weight Management to Prevent the Developmental Programming of MAFLD in Offspring of Obese Mothers

The global surge of obesity amongst women of reproductive age has raised concerns surrounding the health consequences for their offspring as there is a formidable link between an obesogenic maternal environment and the developmental programming of metabolic dysfunction in the offspring. Specifically, the offspring of mothers with obesity have a three-fold higher risk of developing metabolic-associated fatty liver disease (MAFLD) compared to the offspring of healthy-weight mothers. Given the burgeoning burden of obesity and its comorbidities, it is essential to focus research efforts on methods to alleviate the intergenerational onset of obesity and MAFLD. This review summarizes the current research surrounding the developmental programming of MAFLD in the offspring of mothers with obesity and examines the potential for weight interventions to prevent such metabolic dysfunction in the offspring. It focuses on the benefits of pre-pregnancy interventional strategies, including dietary and exercise intervention, to ameliorate adverse liver health outcomes in the offspring. The utility and translation of these interventions for humans may be difficult for prospective mothers with obesity, thus the use of pre-pregnancy therapeutic weight loss aids, such as glucagon-like peptide-1 receptor agonists, is also discussed.

Pregnancy and Metabolic-Associated Fatty Liver Disease

Metabolic-associated fatty liver disease (MAFLD), the term proposed to substitute nonalcoholic fatty liver disease, comprises not only liver features but also potentially associated metabolic dysfunctions. Since experimental studies in mice and retrospective clinical studies in humans investigated the association between nonalcoholic fatty liver disease during pregnancy and the adverse clinical outcomes in mothers and offspring, it is plausible that MAFLD may cause similar or worse effects on mother and the offspring. Only a few studies have investigated the possible association of maternal MAFLD with more severe pregnancy-related complications. This article provides an overview of the evidence for this dangerous liaison.

Effect of Gestational Fish Oil Supplementation on Liver Metabolism and Mitochondria of Male and Female Rat Offspring Programmed by Maternal High-Fat Diet

SCOPE

Perinatal maternal moderately high-fat diet (mHFD) is associated with obesity and fatty liver disease in offspring, and maternal fish oil (FO: n-3 PUFA source) supplementation may attenuate these disorders. This study evaluates the effects of FO given to pregnant rats fed a mHFD on the offspring's liver at weaning.

METHODS AND RESULTS

Female Wistar rats receive an isoenergetic, control (CT: 10.9% from fat) or high-fat (HF: 28.7% from fat) diet before mating, and throughout pregnancy and lactation. FO supplementation (HFFO: 2.9% of FO in the HF diet) is given to one subgroup of HF dams during pregnancy. At weaning, male and female mHFD offspring display higher body mass, adiposity, and hepatic cellular damage, steatosis, and inflammation, accompanied by increased damaged mitochondria. FO does not protect pups from systemic metabolic alterations and partially mitigates hepatic histological damage induced by mHFD only in females. However, FO reduces mRNA expression of lipogenic genes, and mitochondrial damage, and modified mitochondrial morphology suggestive of early adaptations via mitochondrial dynamics.

CONCLUSIONS

Gestational FO supplementation has limited beneficial effects on the damage caused by perinatal mHFD consumption in offspring's liver at weaning. However, FO imprinting effect on lipid metabolism and mitochondria may have beneficial long-term outcomes.

Severe gestational diabetes mellitus in lean dams is associated with low IL-1α levels and affects the growth of the juvenile mouse offspring

We investigated how maternal gestational diabetes (GDM) impacts the metabolic status of offspring. GDM was induced in CD1 mice consuming a fast-food diet (FFD) by repeated low-dose streptozotocin injections before mating. Offspring of normoglycemic standard chow or the FFD consuming dams served as controls. In 4-week-old offspring weaned to standard chow, plasma concentrations of extracellular DNA, inflammatory markers, and parameters of the cardiometabolic status (glycemia, liver lipid content; body, organ, and fat weight) were determined. Two-factor analysis of variance indicated that the male offspring of GDM dams manifest postnatal growth retardation and lower relative kidney weight. Regardless of sex, GDM offspring manifest the lowest IL-1α levels, and other inflammatory markers showed mild and inconsistent alterations. Offspring of dams consuming the FFD displayed higher liver triacylglycerols content. The three groups of offspring showed no significant differences in glycemia and extracellular DNA. Partial least squares-discriminant analysis indicated that male GDM offspring present lower kidney, body, and brown adipose tissue weights; lower IL-1α levels, and higher concentrations of GM-CSF and IL-10 compared with their FFD counterparts. The model failed to select discriminative variables in females. In conclusion, in mice, maternal GDM in the absence of obesity adversely affects the early growth of juvenile male offspring.

Pregnancy and Metabolic-associated Fatty Liver Disease: A Clinical Update

The intricate relationship between metabolic-associated fatty liver disease (MAFLD) and maternal complications has rapidly become a significant health threat in pregnant women. The presence of MAFLD in pregnancy increases the maternal risk of metabolic complications and comorbidities for both mother and baby. The preexistence or development of MAFLD in pregnancy is a complex multifactorial disorder that can lead to further complications for mother and baby. Therefore, as pregnant women are severely underrepresented in clinical research, there is a great need for a fair inclusion of this group in clinical trials. This review aims to explore the effects of MAFLD during pregnancy in the context of maternal complications and outcomes and explore the effects of pregnancy on the development and progression of MAFLD within the context of maternal obesity, altered metabolic profiles, gestational diabetes and altered hormonal profiles. We also addressed potential implications for the presence of MAFLD during pregnancy and its management in the clinical setting.

The Legacy of Parental Obesity: Mechanisms of Non-Genetic Transmission and Reversibility

While a dramatic increase in obesity and related comorbidities is being witnessed, the underlying mechanisms of their spread remain unresolved. Epigenetic and other non-genetic mechanisms tend to be prominent candidates involved in the establishment and transmission of obesity and associated metabolic disorders to offspring. Here, we review recent findings addressing those candidates, in the context of maternal and paternal influences, and discuss the effectiveness of preventive measures.

Diet Modification before or during Pregnancy on Maternal and Foetal Outcomes in Rodent Models of Maternal Obesity

The obesity epidemic has serious implications for women of reproductive age; its rising incidence is associated not just with health implications for the mother but also has transgenerational ramifications for the offspring. Increased incidence of diabetes, cardiovascular disease, obesity, and kidney disease are seen in both the mothers and the offspring. Animal models, such as rodent studies, are fundamental to studying maternal obesity and its impact on maternal and offspring health, as human studies lack rigorous controlled experimental design. Furthermore, the short and prolific reproductive potential of rodents enables examination across multiple generations and facilitates the exploration of interventional strategies to mitigate the impact of maternal obesity, both before and during pregnancy. Given that obesity is a major public health concern, it is important to obtain a greater understanding of its pathophysiology and interaction with reproductive health, placental physiology, and foetal development. This narrative review focuses on the known effects of maternal obesity on the mother and the offspring, and the benefits of interventional strategies, including dietary intervention, before or during pregnancy on maternal and foetal outcomes. It further examines the contribution of rodent models of maternal obesity to elucidating pathophysiological pathways of disease development, as well as methods to reduce the impact of obesity on the mothers and the developing foetus. The translation of these findings into the human experience will also be discussed.

Temporary Increased LDL-C in Offspring with Extreme Elevation of Maternal Preconception Estradiol: A Retrospective Cohort Study

Objective

To investigate the effect of maternal estradiol (E₂) elevation on long-term metabolic manifestations in the offspring.

Study Design and Setting

This was a retrospective cohort study. Overall, 3690 children conceived by in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) between July 2014 and December 2017 were recruited and divided into four groups categorized by maternal E₂ quartiles (Q1, <2420; Q2, 2420–3839; Q3, 3839–5599; and Q4, ≥5599 pg/mL). The metabolic profiles were measured during childhood. Linear mixed models were used to evaluate the association between maternal E₂ elevation and metabolic phenotypes of the offspring.

Results

Lipoprotein cholesterol (LDL-C) was significantly higher in the highest quartile group than in the lowest quartile group during infancy (adjusted mean difference [95% confidence interval, CI]): 0.11 [0.02, 0.20], P = 0.005), but the difference disappeared in the later childhood phase. In children born after fresh embryo transfer, LDL-C showed an increasing trend with the increase in maternal E₂ level (adjusted mean difference [95% CI]: Q2 vs Q1, −0.01 [−0.11, 0.08], Q3 vs Q1, 0.06 [−0.04, 0.15], Q4 vs Q1, 0.10 [0, 0.20]). Other metabolic variables were comparable across increasing quartiles of maternal E₂ levels.

Conclusion

This study demonstrates a temporary increase in LDL-C levels in infants with higher levels of maternal preconception E₂ levels. However, the long-term safety of hyperestrogens after ovarian stimulation in the next generation is favorable. The mechanism underlying the transiently increased metabolic dysfunction risk in infants conceived by IVF/ICSI requires investigation in future studies.

Maternal obesogenic diet regulates offspring bile acid homeostasis and hepatic lipid metabolism via the gut microbiome in mice

Mice exposed in gestation to maternal high-fat/high-sucrose (HF/HS) diet develop altered bile acid (BA) homeostasis. We hypothesized that these reflect an altered microbiome and asked if microbiota transplanted from HF/HS offspring change hepatic BA and lipid metabolism to determine the directionality of effect. Female mice were fed HF/HS or chow (CON) for 6 wk and bred with lean males. 16S sequencing was performed to compare taxa in offspring. Cecal microbiome transplantation (CMT) was performed from HF/HS or CON offspring into antibiotic-treated mice fed chow or high fructose. BA, lipid metabolic, and gene expression analyses were performed in recipient mice. Gut microbiomes from HF/HS offspring segregated from CON offspring, with increased Firmicutes to Bacteriodetes ratios and Verrucomicrobial abundance. After CMT was performed, HF/HS-recipient mice had larger BA pools, increased intrahepatic muricholic acid, and decreased deoxycholic acid species. HF/HS-recipient mice exhibited downregulated hepatic Mrp2, increased hepatic Oatp1b2, and decreased ileal Asbt mRNA expression. HF/HS-recipient mice exhibited decreased cecal butyrate and increased hepatic expression of Il6. HF/HS-recipient mice had larger livers and increased intrahepatic triglyceride versus CON-recipient mice after fructose feeding, with increased hepatic mRNA expression of lipogenic genes including Srebf1, Fabp1, Mogat1, and Mogat2. CMT from HF/HS offspring increased BA pool and shifted the composition of the intrahepatic BA pool. CMT from HF/HS donor offspring increased fructose-induced liver triglyceride accumulation. These findings support a causal role for vertical transfer of an altered microbiome in hepatic BA and lipid metabolism in HF/HS offspring.NEW & NOTEWORTHY We utilized a mouse model of maternal obesogenic diet exposure to evaluate the effect on offspring microbiome and bile acid homeostasis. We identified shifts in the offspring microbiome associated with changes in cecal bile acid levels. Transfer of the microbiome from maternal obesogenic diet-exposed offspring to microbiome-depleted mice altered bile acid homeostasis and increased fructose-induced hepatic steatosis.

Maternal Isocaloric High-Fat Diet Induces Liver Mitochondria Maladaptations and Homeostatic Disturbances Intensifying Mitochondria Damage in Response to Fructose Intake in Adult Male Rat Offspring

SCOPE

Perinatal maternal obesity and excessive fructose consumption have been associated with liver metabolic diseases. We investigated whether moderate maternal high-fat diet affects the liver mitochondria responses to fructose intake in adult offspring.

METHODS AND RESULTS

Wistar female rats received a standard diet (mSTD) or high-fat diet (mHFD) (9% and 28.6% fat, respectively), before mating until the end of lactation. Male offspring were fed standard diet from weaning to adulthood and received water or fructose-drinking water (15%) from 120 to 150 days old. Fructose induced liver mitochondrial ultrastructural alterations with higher intensity in mHFD offspring, accompanied by reduced autophagy markers. Isolated mitochondria respirometry showed unaltered ATP-coupled oxygen consumption with increased Atp5f1b mRNA only in mHFD offspring. Fructose increased basal respiration and encoding complex I-III mRNA, only in mSTD offspring. Uncoupled respiration was lower in mHFD mitochondria that were unable to exhibit fructose-induced increase Ucp2 mRNA. Fructose decreased antioxidative defense markers, increased unfolded protein response and insulin resistance only in mHFD offspring without fructose-induced hepatic lipid accumulation.

CONCLUSION

Mitochondrial dysfunction and homeostatic disturbances in response to fructose are early events evidencing the higher risk of fructose damage in the liver of adult offspring from dams fed an isocaloric moderate high-fat diet. This article is protected by copyright. All rights reserved.

Role of the Gut Microbiota in Regulating Non-alcoholic Fatty Liver Disease in Children and Adolescents

Non-alcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease in children and adolescents. Although obesity is the leading cause of NAFLD, the etiologies of NAFLD are multifactorial (e.g., high-fat diet, a lack of exercise, gender, maternal obesity, the antibiotic use), and each of these factors leads to dysbiosis of the gut microbiota community. The gut microbiota is a key player in the development and regulation of the gut mucosal immune system as well as the regulation of both NAFLD and obesity. Dysbiosis of the gut microbiota promotes the development of NAFLD via alteration of gut-liver homeostasis, including disruption of the gut barrier, portal transport of bacterial endotoxin (lipopolysaccharide) to the liver, altered bile acid profiles, and decreased concentrations of short-chain fatty acids. In terms of prevention and treatment, conventional approaches (e.g., dietary and exercise interventions) against obesity and NAFLD have been confirmed to recover the dysbiosis and dysbiosis-mediated altered metabolism. In addition, increased understanding of the importance of gut microbiota-mediated homeostasis in the prevention of NAFLD suggests the potential effectiveness of gut microbiota-targeted preventive and therapeutic strategies (e.g., probiotics and fecal transplantation) against NAFLD in children and adolescents. This review comprehensively summarizes our current knowledge of the gut microbiota, focusing on its interaction with NAFLD and its potential therapeutic role in obese children and adolescents with this disorder.

Maternal high-fat diet disrupted one-carbon metabolism in offspring, contributing to nonalcoholic fatty liver disease

BACKGROUND & AIMS

Pregnant women may transmit their metabolic phenotypes to their offspring, enhancing the risk for nonalcoholic fatty liver disease (NAFLD); however, the molecular mechanisms remain unclear.

METHODS

Prior to pregnancy female mice were fed either a maternal normal-fat diet (NF-group, "no effectors"), or a maternal high-fat diet (HF-group, "persistent effectors"), or were transitioned from a HF to a NF diet before pregnancy (H9N-group, "effectors removal"), followed by pregnancy and lactation, and then offspring were fed high-fat diets after weaning. Offspring livers were analysed by functional studies, as well as next-generation sequencing for gene expression profiles and DNA methylation changes.

RESULTS

The HF, but not the H9N offspring, displayed glucose intolerance and hepatic steatosis. The HF offspring also displayed a disruption of lipid homeostasis associated with an altered methionine cycle and abnormal one-carbon metabolism that caused DNA hypermethylation and L-carnitine depletion associated with deactivated AMPK signalling and decreased expression of PPAR-α and genes for fatty acid oxidation. These changes were not present in H9N offspring. In addition, we identified maternal HF diet-induced genes involved in one-carbon metabolism that were associated with DNA methylation modifications in HF offspring. Importantly, the DNA methylation modifications and their associated gene expression changes were reversed in H9N offspring livers.

CONCLUSIONS

Our results demonstrate for the first time that maternal HF diet disrupted the methionine cycle and one-carbon metabolism in offspring livers which further altered lipid homeostasis. CpG islands of specific genes involved in one-carbon metabolism modified by different maternal diets were identified.

Maternal Exercise Mediates Hepatic Metabolic Programming via Activation of AMPK-PGC1α Axis in the Offspring of Obese Mothers

Maternal obesity is associated with an increased risk of hepatic metabolic dysfunction for both mother and offspring and targeted interventions to address this growing metabolic disease burden are urgently needed. This study investigates whether maternal exercise (ME) could reverse the detrimental effects of hepatic metabolic dysfunction in obese dams and their offspring while focusing on the AMP-activated protein kinase (AMPK), representing a key regulator of hepatic metabolism. In a mouse model of maternal western-style-diet (WSD)-induced obesity, we established an exercise intervention of voluntary wheel-running before and during pregnancy and analyzed its effects on hepatic energy metabolism during developmental organ programming. ME prevented WSD-induced hepatic steatosis in obese dams by alterations of key hepatic metabolic processes, including activation of hepatic ß-oxidation and inhibition of lipogenesis following increased AMPK and peroxisome-proliferator-activated-receptor-γ-coactivator-1α (PGC-1α)-signaling. Offspring of exercised dams exhibited a comparable hepatic metabolic signature to their mothers with increased AMPK-PGC1α-activity and beneficial changes in hepatic lipid metabolism and were protected from WSD-induced adipose tissue accumulation and hepatic steatosis in later life. In conclusion, this study demonstrates that ME provides a promising strategy to improve the metabolic health of both obese mothers and their offspring and highlights AMPK as a potential metabolic target for therapeutic interventions.

Maternal obesity accelerated non-alcoholic fatty liver disease in offspring mice by reducing autophagy

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease characterized by an excessive accumulation of triacylglycerol in the liver. Autophagy is a lysosome-dependent degradation product recovery process, which widely occurs in eukaryotic cells, responsible for the vital maintenance of cellular energy balance. Previously published studies have demonstrated that autophagy is closely related to NAFLD occurrence and maternal obesity increases the susceptibility of offspring to non-alcoholic fatty liver disease, however, the underlying mechanism of this remains unclear. In the present study, NAFLD mouse models (offspring of an obese mother mouse via high-fat feeding) were generated, and the physiological indices of the liver were observed using total cholesterol, triglyceride, high-density lipoprotein and low-density lipoprotein serum assay kits. The morphological changes of the liver were also observed via HE, Masson and oil red O staining. Reverse transcription-quantitative-PCR and western blotting were performed to detect changes of autophagy-related genes in liver or fibrosis marker proteins (α-smooth muscle actin or TGF-β₁). Changes in serum inflammatory cytokine IL-6 levels were determined via ELISA. The results of the present study demonstrated that the offspring of an obese mother were more likely to develop NALFD than the offspring of a chow-fed mother, due to their increased association with liver fibrosis. When feeding continued to 17 weeks, the worst cases of NAFLD were observed and the level of autophagy decreased significantly compared with the offspring of a normal weight mouse. In addition, after 17 weeks of feeding, compared with the offspring of a chow-fed mother, the offspring of an obese mouse mother had reduced adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) phosphorylation levels and increased mammalian target of rapamycin (mTOR) phosphorylation levels. These results suggested that a reduced level of AMPK/mTOR mediated autophagy may be of vital importance for the increased susceptibility of offspring to NAFLD caused by maternal obesity. In conclusion, the current study provided a new direction for the treatment of NAFLD in offspring caused by maternal obesity.

Epigenetic Biomarkers for the Diagnosis and Treatment of Liver Disease

Research in the last decades has demonstrated the relevance of epigenetics in controlling gene expression to maintain cell homeostasis, and the important role played by epigenome alterations in disease development. Moreover, the reversibility of epigenetic marks can be harnessed as a therapeutic strategy, and epigenetic marks can be used as diagnosis biomarkers. Epigenetic alterations in DNA methylation, histone post-translational modifications (PTMs), and non-coding RNA (ncRNA) expression have been associated with the process of hepatocarcinogenesis. Here, we summarize epigenetic alterations involved in the pathogenesis of chronic liver disease (CLD), particularly focusing on DNA methylation. We also discuss their utility as epigenetic biomarkers in liquid biopsy for the diagnosis and prognosis of hepatocellular carcinoma (HCC). Finally, we discuss the potential of epigenetic therapeutic strategies for HCC treatment.

Maternal resistance to diet-induced obesity partially protects newborn and post-weaning male mice offspring from metabolic disturbances

The rising rate of childhood overweight follows the increase in maternal obesity, since perinatal events impact offspring in a diversity of metabolic disorders. Despite many studies that have linked dietary consumption, overnutrition, or maternal obesity as the mediators of fetal metabolic programming, there are gaps regarding the knowledge about the contribution of different maternal phenotypes to the development of metabolic disturbances in offspring. This study aimed to investigate whether maternal high-fat diet (HFD) consumption without the development of the obese phenotype would protect offspring from metabolic disturbances. Female mice were fed standard chow diet or a HFD for 4 weeks before mating. HFD females were classified into obesity-resistant (OR) or obesity-prone (OP), according to weight gain. OP females presented with higher adiposity, fasting serum glucose and insulin, cholesterol and non-esterified fatty acid (NEFA). Newborn offspring from OP dams showed higher serum glucose and insulin and alteration in hepatic gene expression that may have contributed to the rise in hepatic fat content and decline of glycogen levels in the liver. Despite offspring from OR and OP females having showed similar growth after the day of delivery, offspring from OP females had higher caloric intake, fasting glucose, serum triglycerides and altered hepatic gene expression, as well as glucose and pyruvate intolerance and lower insulin sensitivity at d28 compared with offspring from OR females. Maternal pre-pregnancy serum glucose, insulin, and NEFA positively correlated with serum glucose and fat liver content and negatively correlated with hepatic glycogen in offspring. In conclusion, our results show that maternal resistance to diet-induced obesity partially protects offspring from early metabolic disturbances.

Pregestational diet transition to normal-fat diet avoids the deterioration of pancreatic β-cell function in male offspring induced by maternal high-fat diet

Novel progress has been made to understand the adverse pathophysiology in the pancreas of offspring exposed to overnutrition in utero. Our study is the first to evaluate whether the adverse effects of maternal overnutrition on offspring β-cell function are reversible or preventable through preconception maternal diet interventions. Herein, offspring mice were exposed in utero to one of the following: maternal normal-fat diet (NF group), maternal high-fat diet (HF group) or maternal diet transition from an HF to NF diet 9 weeks before pregnancy (H9N group). Offspring mice were subjected to postweaning HF diet for 12 weeks. HF offspring, but not H9N, displayed glucose intolerance and insulin resistance. HF male offspring had enlarged islet β-cells with reduced β-cell density, whereas, H9N male offspring did not show these changes. Co-immunofluorescent (Co-IF) staining of glucose transporter 2 (Glut2) and insulin (Ins) revealed significantly more Glut2⁺Ins^- cells, indicative of insulin degranulation, in HF male offspring but not H9N. In addition, Co-IF of insulin and p-H3S10 indicated that β cells of HF male offspring, but not H9N, had proliferation defects likely due to inhibited protein kinase B (AKT) phosphorylation. In summary, our study demonstrates that maternal H9N diet effectively prevents functional deterioration of β cells seen in HF male offspring by avoiding β-cell proliferation defects and degranulation.

Developmental Programming of NAFLD by Parental Obesity

The surge of obesity across generations has become an increasingly relevant issue, with consequences for associated comorbidities in offspring. Data from longitudinal birth cohort studies support an association between maternal obesity and offspring nonalcoholic fatty liver disease (NAFLD), suggesting that perinatal obesity or obesogenic diet exposure reprograms offspring liver and increases NAFLD susceptibility. In preclinical models, offspring exposed to maternal obesogenic diet have increased hepatic steatosis after diet-induced obesity; however, the implications for later NAFLD development and progression are still unclear. Although some models show increased NAFLD incidence and progression in offspring, development of nonalcoholic steatohepatitis with fibrosis may be model dependent. Multigenerational programming of NAFLD phenotypes occurs after maternal obesogenic diet exposure; however, the mechanisms for such programming remain poorly understood. Likewise, emerging data on the role of paternal obesity in offspring NAFLD development reveal incomplete mechanisms. This review will explore the impact of parental obesity and obesogenic diet exposure on offspring NAFLD and areas for further investigation, including the impact of parental diet on disease progression, and consider potential interventions in preclinical models.