Treating IPF--all or nothing? A PRO-CON debate

Molecular Mechanisms of Pulmonary Fibrogenesis and Its Progression to Lung Cancer: A Review

Idiopathic pulmonary fibrosis (IPF) is defined as a specific form of chronic, progressive fibrosing interstitial pneumonia of unknown cause, occurring primarily in older adults, and limited to the lungs. Despite the increasing research interest in the pathogenesis of IPF, unfavorable survival rates remain associated with this condition. Recently, novel therapeutic agents have been shown to control the progression of IPF. However, these drugs do not improve lung function and have not been tested prospectively in patients with IPF and coexisting lung cancer, which is a common comorbidity of IPF. Optimal management of patients with IPF and lung cancer requires understanding of pathogenic mechanisms and molecular pathways that are common to both diseases. This review article reflects the current state of knowledge regarding the pathogenesis of pulmonary fibrosis and summarizes the pathways that are common to IPF and lung cancer by focusing on the molecular mechanisms.

Lung carcinogenesis and fibrosis taken together: just coincidence?

PURPOSE OF REVIEW

The pathogenesis of lung cancer and pulmonary fibrotic disorders partially overlaps. This review focuses on the common features of the two disease categories, aimed at advancing our translational understanding of their pathobiology and at fostering the development of new therapies.

RECENT FINDINGS

Both malignant and collagen-producing lung cells display enhanced cellular proliferation, increased resistance to apoptosis, a propensity for invading and distorting the lung parenchyma, as well as stemness potential. These characteristics are reinforced by the tissue microenvironment and inflammation seems to play an important adjuvant role in both types of disorders.

SUMMARY

Unraveling the thread of the common and distinct characteristics of lung fibrosis and cancer might contribute to a more comprehensive approach of the pathobiology of both diseases and to a pathfinder for novel and personalized therapeutic strategies.

Aerobic Exercise Attenuated Bleomycin-Induced Lung Fibrosis in Th2-Dominant Mice

INTRODUCTION

The aim of this study was to investigate the effect of aerobic exercise (AE) in reducing bleomycin-induced fibrosis in mice of a Th2-dominant immune background (BALB/c).

METHODS

BALB/c mice were distributed into: sedentary, control (CON), Exercise-only (EX), sedentary, bleomycin-treated (BLEO) and bleomycin-treated+exercised (BLEO+EX); (n = 8/group). Following treadmill adaptation, 15 days following a single, oro-tracheal administration of bleomycin (1.5U/kg), AE was performed 5 days/week, 60min/day for 4 weeks at moderate intensity (60% of maximum velocity reached during a physical test) and assessed for pulmonary inflammation and remodeling, and cytokine levels in bronchoalveolar lavage (BAL).

RESULTS

At 45 days post injury, compared to BLEO, BLEO+EX demonstrated reduced collagen deposition in the airways (p<0.001) and also in the lung parenchyma (p<0.001). In BAL, a decreased number of total leukocytes (p<0.01), eosinophils (p<0.001), lymphocytes (p<0.01), macrophages (p<0.01), and neutrophils (p<0.01), as well as reduced pro-inflammatory cytokines (CXCL-1; p<0.01), (IL-1β; p<0.001), (IL-5; p<0.01), (IL-6; p<0.001), (IL-13; p<0.01) and pro-fibrotic growth factor IGF-1 (p<0.001) were observed. Anti-inflammatory cytokine IL-10 was increased (p<0.001).

CONCLUSION

AE attenuated bleomycin-induced collagen deposition, inflammation and cytokines accumulation in the lungs of mice with a predominately Th2-background suggesting that therapeutic AE (15-44 days post injury) attenuates the pro-inflammatory, Th2 immune response and fibrosis in the bleomycin model.

"Scar-cinoma": viewing the fibrotic lung mesenchymal cell in the context of cancer biology

Lung cancer and pulmonary fibrosis are common, yet distinct, pathological processes that represent urgent unmet medical needs. Striking clinical and mechanistic parallels exist between these distinct disease entities. The goal of this article is to examine lung fibrosis from the perspective of cancer-associated phenotypic hallmarks, to discuss areas of mechanistic overlap and distinction, and to highlight profibrotic mechanisms that contribute to carcinogenesis. Ultimately, we speculate that such comparisons might identify opportunities to leverage our current understanding of the pathobiology of each disease process in order to advance novel therapeutic approaches for both. We anticipate that such "outside the box" concepts could be translated to a more precise and individualised approach to fibrotic diseases of the lung.