The Role of Inflammation in the Pathogenesis of Pulmonary Fibrosis: Mechanisms and Treatment Implications

Fibrotic interstitial lung diseases (fILDs) encompass a heterogeneous group of interstitial lung diseases (ILDs) and may arise from persistent inflammation caused by systemic disease or environmental exposures. Idiopathic pulmonary fibrosis (IPF), the prototypical fILD, is characterized by progressive fibrosis, limited inflammation, and a high mortality rate. In contrast, other fILDs display variable contributions of fibrosis and inflammation that are only partially determined by the underlying diagnosis. Within most fILDs, a broad spectrum of disease phenotypes can be observed. Inflammation and fibrosis are not discrete, sequential events but rather dynamically intertwined processes. The nature and relative importance of these interactions vary according to the underlying etiology. Inflammation can function as both a driver and a consequence of fibrotic remodeling, establishing self-perpetuating feed-forward loops, yet also playing a role in fibrosis resolution and control. As therapeutic strategies for predominantly fibrotic versus inflammatory ILDs differ substantially, improved understanding of the pathomechanisms that drive fibrosis is essential for optimizing personalized treatment approaches. Fibrotic and inflammatory signaling pathways show considerable overlap, and their interaction is central to disease initiation and progression. Elucidating the mechanisms that govern cellular responses to diverse injurious stimuli provides an opportunity to refine patient stratification and tailor therapies to improve outcomes. Insights from experimental models of pulmonary fibrosis (PF) and translational research have significantly advanced our understanding of these processes and are reviewed in this article, together with current therapeutic advances and future directions.