Longitudinal serological assessment of type VI collagen turnover is related to progression in a real-world cohort of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF): Diagnostic routes using novel biomarkers

Idiopathic pulmonary fibrosis (IPF) diagnosis is still the diagnosis of exclusion. Differentiating from other forms of interstitial lung diseases (ILDs) is essential, given the various therapeutic approaches. The IPF course is now unpredictable for individual patients, although some genetic factors and several biomarkers have already been associated with various IPF prognoses. Since its early stages, IPF may be asymptomatic, leading to a delayed diagnosis. The present review critically examines the recent literature on molecular biomarkers potentially useful in IPF diagnostics. The examined biomarkers are grouped into breath and sputum biomarkers, serologically assessed extracellular matrix neoepitope markers, and oxidative stress biomarkers in lung tissue. Fibroblasts and complete blood count have also gained recent interest in that respect. Although several biomarker candidates have been profiled, there has yet to be a single biomarker that proved specific to the IPF disease. Nevertheless, various IPF biomarkers have been used in preclinical and clinical trials to verify their predictive and monitoring potential.

Fibroblasts are not just fibroblasts: clear differences between dermal and pulmonary fibroblasts' response to fibrotic growth factors

Systemic Sclerosis (SSc) hallmark is skin fibrosis, but up to 80% of the patients have fibrotic involvement in the pulmonary system. Antifibrotic drugs which have failed in a general SSc population have now been approved in patients with SSc-associated interstitial lung disease (ILD). This indicates that the fibrotic progression and regulation of fibroblasts likely depend on local factors specific to the tissue type. This study investigated the difference between dermal and pulmonary fibroblasts in a fibrotic setting, mimicking the extracellular matrix. Primary healthy fibroblasts were grown in a crowded environment and stimulated with TGF-β1 and PDGF-AB. The viability, morphology, migration capacity, extracellular matrix formation, and gene expression were assessed: TGF-β1 only increased the viability in the dermal fibroblasts. PDGF-AB increased the migration capacity of dermal fibroblasts while the pulmonary fibroblasts fully migrated. The morphology of the fibroblasts was different without stimulation. TGF-β1 increased the formation of type III collagen in pulmonary fibroblasts, while PDGF-AB increased it in dermal fibroblasts. The gene expression trend of type VI collagen was the opposite after PDGF-AB stimulation. The fibroblasts exhibit different response profiles to TGF-β1 and PDGF-AB; this suggests that drivers of fibrosis are tissue-dependent, which needs to be considered in drug development.

Regional and disease specific human lung extracellular matrix composition

Chronic lung diseases, such as chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF), are characterized by regional extracellular matrix (ECM) remodeling which contributes to disease progression. Previous proteomic studies on whole decellularized lungs have provided detailed characterization on the impact of COPD and IPF on total lung ECM composition. However, such studies are unable to determine the differences in ECM composition between individual anatomical regions of the lung. Here, we employ a post-decellularization dissection method to compare the ECM composition of whole decellularized lungs (wECM) and specific anatomical lung regions, including alveolar-enriched ECM (aECM), airway ECM (airECM), and vasculature ECM (vECM), between non-diseased (ND), COPD, and IPF human lungs. We demonstrate, using mass spectrometry, that individual regions possess a unique ECM signature characterized primarily by differences in collagen composition and basement-membrane associated proteins, including ECM glycoproteins. We further demonstrate that both COPD and IPF lead to alterations in lung ECM composition in a region-specific manner, including enrichment of type-III collagen and fibulin in IPF aECM. Taken together, this study provides methodology for future studies, including isolation of region-specific lung biomaterials, as well as a dataset that may be applied for the identification of novel ECM targets for therapeutics.

Human epididymis protein 4 (HE4) is a novel biomarker for fibrosis in IgG4-related disease and can predict poor prognosis

Objectives

IgG4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory disorder with heterogeneous manifestations. This study aimed to investigate the utility of human epididymis protein 4 (HE4) as a potential clinical biomarker of fibrosis in IgG4-RD.

Methods

Plasma HE4 levels were estimated in 136 patients with IgG4-RD and 73 healthy individuals (controls) by electrochemical luminescence. HE4 expression levels and the degree of fibrosis in pancreatic tissues from 15 patients with IgG4-RD and 10 controls were compared using immunohistochemistry and Masson trichrome staining. Correlation between HE4 levels and laboratory parameters was determined, and the efficacy of HE4 as a biomarker of fibrosis and prognosis in IgG4-RD was also evaluated.

Results

Plasma HE4 levels were significantly higher in patients with IgG4-RD compared with controls. Optimal HE4 cut-off value for identifying patients with IgG4-RD was determined to be 50.8 pmol/L with an AUC (area under curve) of 0.791. HE4 levels were positively correlated with diverse laboratory parameters, and indicators of organ function impairment. Additionally, HE4 was highly expressed in the affected organs in patients with IgG4-RD and its plasma levels were closely correlated with degree of fibrosis, indicating the utility of HE4 in assessing internal organ damage and fibrosis. Further analysis showed that patients in the HE4 high expression group had poor prognosis.

Conclusions

Our results demonstrate that HE4 can be used as a biomarker for IgG4-RD as it is correlated with diverse baseline clinical features, internal organ damage and degree of fibrosis in affected organs, and can predict poor prognosis.