Maternal obesogenic diet enhances cholestatic liver disease in offspring

Maternal Western Diet Programmes Bile Acid Dysregulation and Hepatic Fibrosis in Fetal and Juvenile Macaques

BACKGROUND AND AIMS

Maternal obesity increases the risk of the paediatric form of metabolic dysfunction-associated steatotic liver disease (MASLD), affecting up to 30% of youth, but the developmental origins remain poorly understood.

METHODS

Using a Japanese macaque model, we investigated the impact of maternal Western-style diet (mWSD) or chow diet followed by postweaning WSD (pwWSD) or chow diet focusing on bile acid (BA) homeostasis and hepatic fibrosis in livers from third-trimester fetuses and 3-year-old juvenile offspring.

RESULTS

Juveniles exposed to mWSD had increased hepatic collagen I/III content and stellate cell activation in portal regions. mWSD increased transcriptional signatures of FXR activation, while pwWSD impaired FXR pathway genes and increased liver BA content. Both mWSD and pwWSD increased serum BA concentrations. Notably, mWSD-exposed juvenile offspring had increased periportal CK19 expression and cholangiocyte gene expression supporting proliferation compared with maternal chow-exposed offspring. Fetuses exposed to mWSD had increased CK19 expression and hepatic BAs which correlated positively with periportal collagen deposition and negatively with markers of fetal oxygenation. In juvenile offspring, increased serum BAs correlated positively with hepatic oxidative stress and portal fibrosis without elevated liver enzymes.

CONCLUSIONS

mWSD is associated with hallmarks of paediatric MASLD including portal bile ductular reaction, portal fibrosis and dysregulated BA homeostasis. These conditions begin in utero and persist in juvenile offspring regardless of their postweaning diet. These findings implicate changes in BA metabolism that may drive developmental programming of MASLD in juvenile offspring beginning in utero.

Thermoneutral Housing Enables Studies of Vertical Transmission of Obesogenic Diet-Driven Metabolic Diseases

Vertical transmission of obesity is a critical contributor to the unabated obesity pandemic and the associated surge in metabolic diseases. Existing experimental models insufficiently recapitulate "human-like" obesity phenotypes, limiting the discovery of how severe obesity in pregnancy instructs vertical transmission of obesity. Here, via utility of thermoneutral housing and obesogenic diet feeding coupled to syngeneic mating of WT obese female and lean male mice on a C57BL/6 background, we present a tractable, more "human-like" approach to specifically investigate how maternal obesity contributes to offspring health. Using this model, we found that maternal obesity decreased neonatal survival, increased offspring adiposity, and accelerated offspring predisposition to obesity and metabolic disease. We also show that severe maternal obesity was sufficient to skew offspring microbiome and create a proinflammatory gestational environment that correlated with inflammatory changes in the offspring in utero and adulthood. Analysis of a human birth cohort study of mothers with and without obesity and their infants was consistent with mouse study findings of maternal inflammation and offspring weight gain propensity. Together, our results show that dietary induction of obesity in female mice coupled to thermoneutral housing can be used for future mechanistic interrogations of obesity and metabolic disease in pregnancy and vertical transmission of pathogenic traits.

Maternal Exercise Protects Male Offspring From Maternal Diet-Programmed Nonalcoholic Fatty Liver Disease Progression

Maternal obesity programs the risk for development of nonalcoholic fatty liver disease (NAFLD) in offspring. Maternal exercise is a potential intervention to prevent developmentally programmed phenotypes. We hypothesized that maternal exercise would protect from progression of NAFLD in offspring previously exposed to a maternal obesogenic diet. Female mice were fed chow (CON) or high fat, fructose, cholesterol (HFFC) and bred with lean males. A subset had an exercise wheel introduced 4 weeks after starting the diet to allow for voluntary exercise. The offspring were weaned to the HFFC diet for 7 weeks to induce NAFLD. Serum, adipose, and liver tissue were collected for metabolic, histologic, and gene expression analyses. Cecal contents were collected for 16S sequencing. Global metabolomics was performed on liver. Female mice fed the HFFC diet had increased body weight prior to adding an exercise wheel. Female mice fed the HFFC diet had an increase in exercise distance relative to CON during the preconception period. Exercise distance was similar between groups during pregnancy and lactation. CON-active and HFFC-active offspring exhibited decreased inflammation compared with offspring from sedentary dams. Fibrosis increased in offspring from HFFC-sedentary dams compared with CON-sedentary. Offspring from exercised HFFC dams exhibited less fibrosis than offspring from sedentary HFFC dams. While maternal diet significantly affected the microbiome of offspring, the effect of maternal exercise was minimal. Metabolomics analysis revealed shifts in multiple metabolites including several involved in bile acid, 1-carbon, histidine, and acylcarnitine metabolism. This study provides preclinical evidence that maternal exercise is a potential approach to prevent developmentally programmed liver disease progression in offspring.