Innovative Approaches to NAFLD: Exploring the Role of Nicotinamide in Multicellular Microtissue Models of Liver Fibrosis

Abstract

In non-alcoholic fatty liver disease (NAFLD), characterised by progressive liver damage, inflammation, fibrosis and potential cirrhosis, treatment options are limited, with liver transplantation as the only definitive solution. To address this urgent need, in vitro and tissue engineering studies have explored new drugs. This study investigated the anti-inflammatory and anti-fibrotic potential of Nicotinamide, utilising promising preliminary data for treating NAFLD. Multicellular liver microtissues comprising LX2 stellate cells, HepG2 hepatocytes and HUVECs were generated to establish a robust preclinical model for fibrosis. Cell viability and histological assessments confirmed successful co-aggregation within the microtissues. To induce fibrosis, they were treated with a palmitic and oleic acid mixture, followed by exposure to Nicotinamide. Treatment effectiveness was evaluated by analysing inflammatory factors, including transforming growth factor β1 (TGF-β1), tumour necrosis factor-alpha (TNF-α) and interleukin 1 beta and interleukin 6. Extracellular matrix deposition was assessed by measuring collagen type I (COL I) and α-smooth muscle actin (α-SMA). Our data suggested that Nicotinamide application led to significant improvements across several measures. Specifically, it effectively reduced inflammatory response by reducing TGF-β1 levels and decreasing COL I and α-SMA levels. Furthermore, Nicotinamide was crucial in reducing reactive oxygen species levels, indicating that activation of HSC, inflammatory signals and oxidative stress work together. These in vitro findings suggest Nicotinamide may have therapeutic potential warranting further investigation in advanced preclinical models. Our findings demonstrated significant improvements across various parameters, including reduced expression of pro-inflammatory cytokines and attenuated oxidative stress, underscoring the therapeutic potential of Nicotinamide in clinical studies.