Maternal exposure to high-fat diet during pregnancy and lactation predisposes normal weight offspring mice to develop hepatic inflammation and insulin resistance

Abstract

Increasing evidence shows a potential link between the perinatal nutrient environment and metabolic outcome in offspring. Here, we investigated the effects of maternal feeding of a high-fat diet (HFD) during the perinatal period on hepatic metabolism and inflammation in male offspring mice at weaning and in early adulthood. Female C57BL/6 J mice were fed HFD or normal chow (NC) for 4 weeks before mating and during pregnancy and lactation. The male offspring mice were weaned onto an NC diet, and metabolic and molecular experiments were performed in early adulthood. At postnatal day 21, male offspring mice from HFD-fed dams (Off-HFD) showed significant increases in whole body fat mass and fasting levels of glucose, insulin, and cholesterol compared to male offspring mice from NC-fed dams (Off-NC). The RT-qPCR analysis showed two- to fivefold increases in hepatic inflammatory markers (MCP-1, IL-1β, and F4/80) in Off-HFD mice. Hepatic expression of G6Pase and PEPCK was elevated by fivefold in the Off-HFD mice compared to the Off-NC mice. Hepatic expression of GLUT4, IRS-1, and PDK4, as well as lipid metabolic genes, CD36, SREBP1c, and SCD1 were increased in the Off-HFD mice compared to the Off-NC mice. In contrast, CPT1a mRNA levels were reduced by 60% in the Off-HFD mice. At postnatal day 70, despite comparable body weights to the Off-NC mice, Off-HFD mice developed hepatic inflammation with increased expression of MCP-1, CD68, F4/80, and CD36 compared to the Off-NC mice. Despite normal body weight, Off-HFD mice developed insulin resistance with defects in hepatic insulin action and insulin-stimulated glucose uptake in skeletal muscle and brown fat, and these metabolic effects were associated with hepatic inflammation in Off-HFD mice. Our findings indicate hidden, lasting effects of maternal exposure to HFD during pregnancy and lactation on metabolic homeostasis of normal weight offspring mice.

Keywords: high-fat diet; inflammation; insulin resistance; lactation; liver; maternal nutrition.

FIGURE 1

Study design and timeline of experimental groups. The control group (chow‐fed dams) was fed a standard chow diet (17% fat), while the HFD group (HFD‐fed dams) was fed a HFD (~60% fat by calories) for 4 weeks prior to mating and throughout pregnancy and lactation. Male offspring mice were housed with their mother until weaning. On postnatal day 21, offspring mice from HFD‐fed dams (Off‐HFD) and NC‐fed dams (Off‐NC) were weaned on a normal chow diet and remained on chow diet for the duration of the study. A subgroup of male offspring mice (n = 4~5/group) was used for fasting blood samples and liver analysis. At postnatal day 70, we performed the metabolic and molecular studies including the 2‐h hyperinsulinemic–euglycemic clamp and using tissues obtained at the end of the clamp from both groups of mice (n = 5~7/group)

FIGURE 2

Changes in body composition of male offspring mice. The longitudinal changes in body weight and whole body lean and fat mass (measured using ¹H‐MRS) in male offspring mice fed chow diet through 10 weeks of age. *p‐value <0.05, **p‐value <0.01

FIGURE 3

Liver expression of inflammatory and metabolic genes in male offspring mice at postnatal day 21. Liver expression of genes associated with (a) Inflammation and macrophages, (b) glucose metabolism, and (c) lipid metabolism in male offspring mice from HFD‐fed dams (Off‐HFD) compared to male offspring mice from normal chow‐fed dams (Off‐NC) at postnatal day 21 (n = 4~5/group). Data were analyzed by Student's t‐test and expressed as means ± SEM. Abbreviations: CD36, Cluster of Differentiation 36; CD68, Cluster of Differentiation 68; CPT1a, Carnitine Palmitoyltransferase 1a; FAS, Fatty Acid Synthase; FATP1, Fatty Acid Transport Protein 1; GLUT4, Glucose Transporter type 4; G6Pase, Glucose‐6‐phosphatase; IL‐1β, Interleukin 1 beta; IL‐6, Interleukin 6; IRS‐1, Insulin Receptor Substrate 1; MCP‐1, Monocyte Chemoattractant Protein 1; PDK4, Pyruvate Dehydrogenase Kinase 4; PEPCK, Phosphoenolpyruvate Carboxykinase; PPARα, Peroxisome Proliferator‐activated Receptor alpha; PPARγ, Peroxisome Proliferator‐activated Receptor gamma; SCD1, Stearoyl CoA Desaturase 1; SREBP1c, Sterol Response Element‐binding Protein 1c; TNFα, Tumor Necrosis Factor alpha. *p‐value <0.05, **p‐value <0.01

FIGURE 4

Insulin action and glucose metabolism in male offspring mice at postnatal day 70. Insulin action and glucose metabolism during a hyperinsulinemic–euglycemic clamp in Off‐NC and Off‐HFD mice on chow diet at postnatal day 70. (a) Glucose infusion rate, (b) hepatic insulin action, (c) hepatic glucose production, (d) whole body glucose turnover, (e) whole body glycogen synthesis, (f) whole body glycolysis, (g) skeletal muscle glucose uptake, (h) white adipose tissue glucose uptake, and (i) brown adipose tissue uptake. Data were analyzed by Student's t‐test. Data are expressed as the mean ± SEM

FIGURE 5

Liver expression of inflammatory and metabolic genes in male offspring mice at postnatal day 70. Hepatic gene expression of (a) inflammatory and macrophage markers, (b) glucose metabolism, and (c) lipid metabolism were determined by RT‐qPCR (n = 5~7/group). Data were analyzed by Student's t‐test. Data are expressed as the mean ± SEM. *p‐value <0.05, **p‐value <0.01