Exploring the Influence of Metabolic Changes in Fibrotic Lung Diseases.

Abstract

Fibrotic lung diseases are often characterized by chronic inflammation and the progressive destruction of the vasculature, parenchyma, and airways, leading to cellular metabolic changes. As a result, these changes activate several pathological pathways, contributing to the disease's progression and worsening. However, the precise impact of metabolic changes and their contributions to the progression of fibrotic lung diseases need deeper exploration. The current review highlights the interplay between immunometabolites and hypoxia in bringing out cellular and epigenetic changes that progress and further exacerbate pulmonary fibrosis. Notably, the mitochondrial-linked immunometabolites such as lactate, succinate, 2-hydroxyglutarate (2-HG), fumarate, and itaconate have the potential to determine cellular fate in health and disease. For instance, lactate accumulation is one of the vital factors associated with pulmonary fibrosis (PF). The metabolite succinate promotes hypoxia response, inflammatory markers accumulation, fibroblast activation, and PF, whereas L-2-HG impairs the TCA cycle, reduces glycolysis, and disrupts the nicotinamide adenine dinucleotide (NADH/NAD+) ratio, ultimately leading to dysfunctional mitochondrial respiration and contributing to lung fibrosis. Due to the progressive and degenerative nature of fibrotic lung diseases, individuals affected by them need ongoing clinical support and monitoring. The currently available pharmacological treatments are limited and come with multiple side effects. Therefore, the search for newer therapeutics in the form of small molecules targeting these metabolites is increasingly being formulated to treat chronic fibrotic pulmonary conditions through their exhaustive mechanistic investigations backed by robust preclinical and clinical trials.