Identification and characterisation of a rare MTTP variant underlying hereditary non-alcoholic fatty liver disease.

Background & Aims: Non-alcoholic fatty liver disease (NAFLD) is a complex trait with an estimated prevalence of 25% globally. We aimed to identify the genetic variant underlying a four-generation family with progressive NAFLD leading to cirrhosis, decompensation, and development of hepatocellular carcinoma in the absence of common risk factors such as obesity and type 2 diabetes. Methods: Exome sequencing and genome comparisons were used to identify the likely causal variant. We extensively characterised the clinical phenotype and post-prandial metabolic responses of family members with the identified novel variant in comparison with healthy non-carriers and wild-type patients with NAFLD. Variant-expressing hepatocyte-like cells (HLCs) were derived from human-induced pluripotent stem cells generated from homozygous donor skin fibroblasts and restored to wild-type using CRISPR-Cas9. The phenotype was assessed using imaging, targeted RNA analysis, and molecular expression arrays. Results: We identified a rare causal variant c.1691T>C p.I564T (rs745447480) in MTTP, encoding microsomal triglyceride transfer protein (MTP), associated with progressive NAFLD, unrelated to metabolic syndrome and without characteristic features of abetalipoproteinaemia. HLCs derived from a homozygote donor had significantly lower MTP activity and lower lipoprotein ApoB secretion than wild-type cells, while having similar levels of MTP mRNA and protein. Cytoplasmic triglyceride accumulation in HLCs triggered endoplasmic reticulum stress, secretion of pro-inflammatory mediators, and production of reactive oxygen species. Conclusions: We have identified and characterised a rare causal variant in MTTP, and homozygosity for MTTP p.I564T is associated with progressive NAFLD without any other manifestations of abetalipoproteinaemia. Our findings provide insights into mechanisms driving progressive NAFLD. Impact and Implications: A rare genetic variant in the gene MTTP has been identified as responsible for the development of severe non-alcoholic fatty liver disease in a four-generation family with no typical disease risk factors. A cell line culture created harbouring this variant gene was characterised to understand how this genetic variation leads to a defect in liver cells, which results in accumulation of fat and processes that promote disease. This is now a useful model for studying the disease pathways and to discover new ways to treat common types of fatty liver disease.

Indian National Association for Study of the Liver (INASL) Guidance Paper on Nomenclature, Diagnosis and Treatment of Nonalcoholic Fatty Liver Disease (NAFLD).

Nonalcoholic fatty liver disease (NAFLD) is a major cause of chronic liver disease globally and in India. The already high burden of NAFLD in India is expected to further increase in the future in parallel with the ongoing epidemics of obesity and type 2 diabetes mellitus. Given the high prevalence of NAFLD in the community, it is crucial to identify those at risk of progressive liver disease to streamline referral and guide proper management. Existing guidelines on NAFLD by various international societies fail to capture the entire landscape of NAFLD in India and are often difficult to incorporate in clinical practice due to fundamental differences in sociocultural aspects and health infrastructure available in India. A lot of progress has been made in the field of NAFLD in the 7 years since the initial position paper by the Indian National Association for the Study of Liver on NAFLD in 2015. Further, the ongoing debate on the nomenclature of NAFLD is creating undue confusion among clinical practitioners. The ensuing comprehensive review provides consensus-based, guidance statements on the nomenclature, diagnosis, and treatment of NAFLD that are practically implementable in the Indian setting.

Development of Food Group Tree-Based Analysis and Its Association with Non-Alcoholic Fatty Liver Disease (NAFLD) and Co-Morbidities in a South Indian Population: A Large Case-Control Study.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is a global problem growing in parallel to the epidemics of obesity and diabetes, with South Asians being particularly susceptible. Nutrition and behaviour are important modifiers of the disease; however, studies to date have only described dietary patterns and nutrients associated with susceptibility to NAFLD. METHODS: This cross-sectional case-control study included 993 NAFLD patients and 973 healthy controls from Trivandrum (India). Dietary data was collected using a locally validated food frequency questionnaire. A tree-based classification categorised 2165 ingredients into three levels (food groups, sub-types, and cooking methods) and intakes were associated with clinical outcomes. RESULTS: NAFLD patients had significantly higher consumption of refined rice, animal fat, red meat, refined sugar, and fried foods, and had lower consumption of vegetables, pulses, nuts, seeds, and milk compared to controls. The consumption of red meat, animal fat, nuts, and refined rice was positively associated with NAFLD diagnosis and the presence of fibrosis, whereas consumption of leafy vegetables, fruits, and dried pulses was negatively associated. Fried food consumption was positively associated with NAFLD, whilst boiled food consumption had a negative association. Increased consumption of animal fats was associated with diabetes, hypertension, and cardiovascular outcomes among those with NAFLD, whereas consumption of wholegrain rice was negatively associated with these clinical-related outcomes. CONCLUSIONS: The tree-based approach provides the first comprehensive method of classifying food intakes to enable the identification of specific dietary factors associated with NAFLD and related clinical outcomes. This could inform culturally sensitive dietary guidelines to reduce risk of NAFLD development and/or its progression.

Cohort profile: the Trivandrum non-alcoholic fatty liver disease (NAFLD) cohort.

PURPOSE: The Trivandrum non-alcoholic fatty liver disease (NAFLD) cohort is a population-based study designed to examine the interaction between genetic and lifestyle factors and their association with increased risk of NAFLD within the Indian population. PARTICIPANTS: Between 2013 and 2016, a total of 2222 participants were recruited to this cohort through multistage cluster sampling across the whole population of Trivandrum-a district within the state of Kerala, South India. Data were collected from all inhabitants of randomly selected households over the age of 25. FINDINGS TO DATE: Full baseline clinical and pathological data were collected from 2158 participants. This included detailed demographic profiles, anthropometric measures and lifestyle data (food frequency, physical activity and anxiety and depression questionnaires). Biochemical profile and ultrasound assessment of the liver were performed and whole blood aliquots were collected for DNA analysis.The NAFLD prevalence within this population was 49.8% which is significantly higher than the global pooled prevalence of 25%. This highlights the importance of robust, prospective studies like this to enable collection of longitudinal data on risk factors, disease progression and to facilitate future interventional studies. FUTURE PLANS: The complete analysis of data collected from this cohort will give valuable insights into the interaction of the phenotypic and genotypic profiles that result in such a dramatic increased risk of NAFLD within the Indian population. The cohort will also form the basis of future lifestyle interventional studies, aimed at improving liver and metabolic health.

Metadoxine Versus Placebo for the Treatment of Non-alcoholic Steatohepatitis: A Randomized Controlled Trial.

OBJECTIVE AND DESIGN: The study aimed at assessing the therapeutic efficacy and safety of metadoxine versus placebo on the ultrasonographic and histological features of non-alcoholic steatohepatitis (NASH). SUBJECTS: 134 subjects with biopsy-confirmed NASH were randomized to receive metadoxine 500 mg two times daily (n = 75) or placebo (n = 59) added to the standard of care, over 16 weeks. EFFICACY ENDPOINTS: Originally, the primary efficacy endpoint was the composite of: reduction in the steatosis by ≥1 grade, reduction in hepatic necro-inflammation by ≥1 grade and ALT normalization. Since >50% of patients refused the second biopsy, it was decided to analyze only the individual parameters. RESULTS: There was no significant difference between the treatment and the placebo groups in either liver histology or ALT or AST. Overall, as expected both groups showed reduction in serum ALT and AST compared to baseline. Compared to placebo (9 out 54), patients on metadoxine (34 out of 75) had significantly higher rates of improvement in 1-point in steatosis grade on ultrasound (P-value <0.001). Safety and tolerability did not differ between treatments. CONCLUSION: Metadoxine is not effective in improvement of liver histology or serum ALT or AST in patients with NASH. However, there was significant improvement of steatosis assessed by ultrasound. To properly estimate the effects on histology and transaminases, further studies of longer duration and at higher doses are needed.