Pooled genetic analysis in ultrasound measured non-alcoholic fatty liver disease in Indian subjects: A pilot study.

AIM: To investigate genetic susceptibility in Indian subjects with non-alcoholic fatty liver disease (NAFLD) by performing a pooled genetic study. METHODS: Study subjects (n = 306) were recruited and categorized into NAFLD and control groups based on ultrasound findings of fatty infiltration. Of the 306 individuals, 156 individuals had fatty infiltration and thus comprised the NAFLD group. One hundred and fifty (n = 150) individuals were normal, without fatty infiltration of the liver, comprising the control group. Blood samples, demographic and anthropometric data from the individuals were collected after obtaining informed consent. Anthropometric data, blood glucose, lipids and liver function tests were estimated using standard methods. Genome wide association studies done to date on NAFLD were identified, 19 single nucleotide polymorphisms (SNPs) were selected from these studies that were reported to be significantly associated with NAFLD and genotyping was performed on the Sequenom platform. Student's t test for continuous variables and χ(2) test was applied to variant carriers from both groups. Required corrections were applied as multiple testing was done. RESULTS The mean age of the control group was 39.78 ± 10.83 and the NAFLD group was 36.63 ± 8.20 years. The waist circumference of males and females in the control and NAFLD groups were 80.13 ± 10.35; 81.77 ± 13.65 and 94.09 ± 10.53; 92.53 ± 8.27 cms respectively. The mean triglyceride and alanine transaminase (ALT) levels in the control and NAFLD groups were 135.18 ± 7.77 mg/dL; 25.39 ± 14.73 IU/L and 184.40 ± 84.31 mg/dL; 110.20 ± 67.05 IU/L respectively. When χ(2) test was applied to the number of individuals carrying the variant risk alleles between the control and NAFLD group, a significant association was seen between rs738409 of the patatin-like phospholipase domain containing 3 (PNPLA3) gene (P = 0.001), rs2073080 of the PARVB gene (P = 0.02), rs2143571 of SAMM50 gene (P = 0.05) and rs6487679 of the pregnancy zone protein (PZP) gene (P = 0.01) with the disease. Variant single nucleotide polymorphisms (SNPs) in NCAN and PNPLA3 gene were associated with higher levels of ALT, whereas variant SNPs in APOC3, PNPLA3, EFCAB4B and COL13A1 were associated with high triglyceride levels. Apart from the above associations, rs2073080, rs343062 and rs6591182 were significantly associated with high BMI; rs2854117 and rs738409 with high triglyceride levels; and rs2073080, rs2143571, rs2228603, rs6487679 and rs738409 with high ALT levels. CONCLUSION: Pooled genetic analysis revealed an association of SNPs in PNPLA3, PARVB, SAMM50 and PZP genes with NAFLD. SNPs in NCAN and PNPLA3 gene were associated with higher levels of ALT, whereas variant SNPs in APOC3, PNPLA3, EFCAB4B and COL13A1 were associated with high triglyceride levels.

Maternal dietary folate and/or vitamin B12 restrictions alter body composition (adiposity) and lipid metabolism in Wistar rat offspring.

Maternal vitamin deficiencies are associated with low birth weight and increased perinatal morbidity and mortality. We hypothesize that maternal folate and/or vitamin B(12) restrictions alter body composition and fat metabolism in the offspring. Female weaning Wistar rats received ad libitum for 12 weeks a control diet (American Institute of Nutrition-76A) or the same with restriction of folate, vitamin B(12) or both (dual deficient) and, after confirming vitamin deficiency, were mated with control males. The pregnant/lactating mothers and their offspring received their respective diets throughout. Biochemical and body composition parameters were determined in mothers before mating and in offspring at 3, 6, 9 and 12 months of age. Vitamin restriction increased body weight and fat and altered lipid profile in female Wistar rats, albeit differences were significant with only B(12) restriction. Offspring born to vitamin-B(12)-restricted dams had lower birth weight, while offspring of all vitamin-restricted dams weighed higher at/from weaning. They had higher body fat (specially visceral fat) from 3 months and were dyslipidemic at 12 months, when they had high circulating and adipose tissue levels of tumor necrosis factor α, leptin and interleukin 6 and low levels of adiponectin and interleukin 1ß. Vitamin-restricted offspring had higher activities of hepatic fatty acid synthase and acetyl-CoA-carboxylase and higher plasma cortisol levels. In conclusion, maternal and peri-/postnatal folate and/or vitamin B(12) restriction increased visceral adiposity (due to increased corticosteroid stress), altered lipid metabolism in rat offspring perhaps by modulating adipocyte function and may thus predispose them to high morbidity later.

Impact of maternal chromium restriction on glucose tolerance, plasma insulin and oxidative stress in WNIN rat offspring.

Robust evidence suggests that nutritional insult during fetal development could program the offspring to glucose intolerance, impaired insulin response and insulin resistance (IR). Considering the importance of chromium (Cr) in maintaining carbohydrate metabolism, this study determined the effect of maternal Cr restriction (CrR) on glucose metabolism and plasma insulin in Wistar/NIN (WNIN) rat offspring and the associated biochemical and/or molecular mechanisms. Female, weanling WNIN rats received ad libitum for 12 weeks, a control diet or the same with 65% restriction of Cr and mated with control males. Some of the Cr-restricted dams were rehabilitated from conception or parturition and their pups weaned on to control diet. At the time of weaning, half of the Cr restricted offspring were rehabilitated to control diet while others continued on Cr-restricted diet. Maternal CrR increased fasting plasma glucose, fasting insulin, homeostasis model assessment of IR, and area under the curve of glucose and insulin during oral glucose tolerance test in the offspring. Expression and activity of rate-limiting enzymes of glucose metabolism were comparable among different groups and expression of genes involved in insulin secretion was increased albeit in male offspring whereas antioxidant enzyme activities were decreased in offspring of both genders. Rehabilitation, in general, corrected the changes albeit partially. Maternal dietary CrR induced IR, impaired glucose tolerance in WNIN rat offspring and was associated with increased oxidative stress, which may predispose them to type 2 diabetes in their later life.

Maternal dietary chromium restriction programs muscle development and function in the rat offspring.

Intrauterine growth retardation programs the fetus to manipulated metabolic changes that lead to adult diseases. Considering that chromium (Cr) supplements influence lean body mass (LBM) in both humans and experimental animals, we have studied the effect of maternal Cr restriction on muscle development and function in the rat offspring. Female weanling Wistar/NIN rats received, for 12 weeks, a control or 65% Cr-restricted diet ad libitum and mated with control males. While control mothers/offspring received control diet throughout (CrC), some restricted mothers were switched to control diet from conception (CrRC) and parturition (CrRP) and their offspring were weaned on to control diet. Half of the remaining restricted pups were weaned on to control diet (CrRW) and the other half continued on restricted diet throughout (CrR). Maternal CrR significantly decreased the percent of LBM (LBM %) and fat-free mass (FFM %) in the offspring and this was associated with decreased expression of the myogenic genes: MyoD, Myf5 and MyoG. Surprisingly, expression of the muscle atrophy genes, Atrogin and MuRF 1, was also decreased in CrR offspring. Although basal glucose uptake by muscle was higher in CrR than in CrC offspring, the stimulation with insulin was comparable, implying no change in its insulin sensitivity. Rehabilitation partly corrected myogenic and atrophic gene expression but had no effect on LBM % or FFM % or glucose uptake by muscle. The results show that maternal Cr restriction in rats may irreversibly impair muscle development and glucose uptake by muscle. Modulation of muscle atrophy appears to be an adaptive mechanism to preserve muscle mass in CrR offspring.