High-Risk PNPLA3 rs738409 Genotype Is Associated with Higher Concentrations of CCL2 in Liver Transplant Candidates with Alcoholic End-Stage Liver Disease

TL;DR

People with a specific genetic variant (PNPLA3 GG) have higher levels of a protein called CCL2 in their blood, which may explain why they are more likely to develop severe liver disease complications.

Contribution

The study identifies a novel association between the PNPLA3 GG genotype and elevated CCL2 levels in patients with alcoholic liver disease.

Findings

GG genotype carriers had significantly higher CCL2 concentrations compared to CC/CG carriers.

GG carriers also showed higher AST and ALT levels and lower platelet counts.

CCL2 levels were not significantly different between ALD patients with and without HCC.

Abstract

Background and Objectives: Patients with GG rs738409 patatin-like phospholipase domain-containing protein 3 (PNPLA3) genotype (148M variant) have greater risk to develop end-stage liver disease and its associated clinical complications, including hepatocellular carcinoma (HCC). We aimed to analyze the association between the PNPLA3 genotype and augmented inflammatory response in transplant candidates with end-stage alcoholic liver disease (ALD). Materials and Methods: Concentrations of 13 cytokines were measured in 106 end-stage ALD patients without HCC (40 with CC, 40 with CG, and 26 with GG genotype), 35 end-stage ALD patients with HCC, and 19 control patients by cytometric bead array. Results: We found significantly higher concentrations of IL-1, IFN-α, IFN-γ, TNF-α, IL-6, CXCL8, IL-10, IL-12, IL-32, and IL-33 in patients with ALD compared to controls, while the concentration of CCL2 was significantly lower. No differences were observed in the concentration of IL-17 and IL-18. ALD patients with and without HCC had similar cytokine concentrations (p > 0.05 for all comparisons). End-stage ALD patients without HCC of the GG genotype had significantly higher CCL2 concentrations (212.6 [135.9–264.9] pg/mL) compared to end-stage ALD patients without HCC carrying the CC/CG genotypes (141.3 [104.1–201.6] pg/mL, p = 0.002, Mann–Whitney). No significant differences across the genotypes were found for the remaining measured cytokines (p > 0.05). GG carriers also had significantly higher levels of AST and ALT, and lower platelet counts. Conclusions: End-stage ALD patients without HCC who carry the PNPLA3 GG genotype have relatively higher CCL2 levels compared to those with the CC or CG genotypes. Relatively elevated CCL2 concentrations in GG patients might contribute to their increased risk of developing clinical complications compared to CC/CG patients.

Figures