PNPLA3 polymorphism increases risk for and severity of chronic hepatitis C liver disease

Mechanisms of Lipid Droplet Accumulation in Steatotic Liver Diseases

The steatotic diseases of metabolic dysfunction-associated steatotic liver disease (MASLD), alcohol-associated liver disease (ALD), and chronic hepatitis C (HCV) account for the majority of liver disease prevalence, morbidity, and mortality worldwide. While these diseases have distinct pathogenic and clinical features, dysregulated lipid droplet (LD) organelle biology represents a convergence of pathogenesis in all three. With increasing understanding of hepatocyte LD biology, we now understand the roles of LD proteins involved in these diseases but also how genetics modulate LD biology to either exacerbate or protect against the phenotypes associated with steatotic liver diseases. Here, we review the history of the LD organelle and its biogenesis and catabolism. We also review how this organelle is critical not only for the steatotic phenotype of liver diseases but also for their advanced phenotypes. Finally, we summarize the latest attempts and challenges of leveraging LD biology for therapeutic gain in steatotic diseases. In conclusion, the study of dysregulated LD biology may lead to novel therapeutics for the prevention of disease progression in the highly prevalent steatotic liver diseases of MASLD, ALD, and HCV.

The role of PNPLA3 and TM6SF2 polymorphisms on liver fibrosis and metabolic abnormalities in Brazilian patients with chronic hepatitis C

Background

Despite the growing body of knowledge about TM6SF2 and PNPLA3 polymorphisms in non-alcoholic fatty liver disease, their influence in the spectrum of HCV liver disease is not yet fully defined. Besides that, admixed populations, such as Brazilians, were not included in most of the studies.

Methods

This cross-sectional study enrolled 365 treatment-naïve patients with HCV and 134 healthy individuals. TM6SF2 (rs58542926 c.499C > T) and PNPLA3 (rs738409 c.444C > G) polymorphisms were evaluated regarding their association with clinical and laboratory data, histological liver steatosis and fibrosis, and with components of the metabolic syndrome.

Results

In HCV subjects, the frequencies of TM6SF2 CC and CT + TT were 89% and 11%, while PNPLA3 frequencies of CC and CG + GG were 51.4% and 48.6%. In the univariate logistic regression analysis, the TM6SF2 CT + TT genotype in HCV was associated with significant liver fibrosis (p = 0.047; OR 1.953; 95% CI 1.009–3.788). In comparison to the CT + TT genotype, the TM6SF2 CC genotype in HCV was associated with older age (p = 0.002), higher frequency of arterial hypertension (p = 0.032), obesity (p = 0.030), metabolic syndrome (p = 0.014) and lower total cholesterol levels (p = 0.036). The PNPLA3 GG subjects had lower body mass index than CG/ CC individuals (p = 0.047). None of the polymorphisms, or their combinations, was independently associated with hepatic steatosis or fibrosis. On the other hand, older age, lower serum levels of total cholesterol, and higher serum levels of alanine aminotransferase and alkaline phosphatase were associated with liver fibrosis in the multivariate logistic regression analysis.

Conclusion

In this evaluation of an admixed HCV population, neither TM6SF2 nor PNPLA3 polymorphisms were independently associated with hepatic steatosis or fibrosis. Other factors seem more influential than these specific polymorphisms in isolation. More studies are warranted to clarify the role of the TM6SF2 and PNPLA3 polymorphisms in Brazilians with HCV.

PNPLA3 polymorphisms are associated with raised alanine aminotransferase levels in hepatitis C virus genotype 3

BACKGROUND AND STUDY AIMS

Hepatitis C virus (HCV) infection is one of the leading causes of end-stage liver diseases. This study aimed to determine the association between polymorphisms in interleukin 28B (IL28B), PNPLA3, toll-like receptor 7 (TLR7), nucleotide-binding oligomerization domain-containing protein 2 (NOD2) and retinoic inducible gene-I (RIG-I) and HCV genotype and clinical presentation in an Indian population.

PATIENTS AND METHODS

A total of 500 patients with chronic HCV were enrolled in 19 centres across India. Genomic DNA was extracted from whole blood samples, and single nucleotide polymorphisms (SNPs) for IL28B, PNPLA3, TLR7, NOD2 and RIG-I genes were genotyped by real-time PCR using a TaqManSNP genotyping assay.

RESULTS

The mean age of the patients was 45 + 13 years, and the most common genotype observed was HCV genotype 3 (54%), followed by genotype 1 (24%). Although the allelic frequencies of TLR7, NOD2 and RIG-I were in significant disequilibrium in HCV patients compared with those in controls, the PNPLA3 polymorphism correlated significantly with higher viral load and alanine aminotransferase (ALT) levels in genotype 3 patients. Patients with PNPLA3 CG/GG genotypes, along with IL28B genotype CC, had higher levels of ALT than those with other genotypes.

CONCLUSION

These results indicate that PNPLA3 polymorphisms are associated with higher ALT levels in HCV genotype 3 patients in India and can help in identifying people who are at greater risk of developing HCV-associated liver diseases.

Role of the PNPLA3 polymorphism rs738409 on silymarin + vitamin E response in subjects with non-alcoholic fatty liver disease

BACKGROUND

non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in developed countries. Lifestyle changes are the pillar of the treatment, although a pharmacological approach is sometimes required in the case of a failure to respond/adhere to the diet.

OBJECTIVE

the aim of this study was to evaluate the effect of silymarin and the influence of the patatin-like phospholipase domain-containing protein 3 (PNPLA3) variant on the response to treatment in patients with NAFLD in a pilot study.

METHODS

a total of 54 patients with a NAFLD proven biopsy were enrolled in an open prospective study and were treated with Eurosil 85® (silymarin + vitamin E) for six months. Biochemical parameters and cardiovascular risk factors (diabetes mellitus, dyslipidemia, hypertriglyceridemia, arterial hypertension and HOMA-IR > 2.5) were recorded before and after six months of treatment. Non-invasive indexes (fatty liver index, lipid accumulation product and NAFLD-fibrosis score) were also calculated. The rs738409 PNPLA3 gene polymorphism status was also determined.

RESULTS

significant statistical changes from baseline values after six months of treatment were observed in transaminases levels but not in non-invasive index markers. Twenty patients (37.1%) were G allele carriers and had a higher percentage of lobular inflammation and ballooning on the basal liver biopsy. Patients with the G allele had a smaller decrease in transaminases levels after treatment with silymarin + vitamin E than non-G-allele carriers.

CONCLUSIONS

treatment with silymarin + vitamin E produced a decrease in transaminases after six months of treatment without an accompanying weight loss. PNPLA3 G-allele carriers responded poorly to the treatment.