External validation and longitudinal application of the DO-GAP index to individualise survival prediction in idiopathic pulmonary fibrosis

Potential role of SIRT-1 and SIRT-3 as biomarkers for the diagnosis and prognosis of idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a debilitating and progressive lung disease of unknown aetiology, characterized by the relentless deposition of fibrotic tissue. Biomarkers may play a pivotal role as indicators of disease presence, progression, and treatment response. Sirtuins, a family of enzymes with ADP ribosyltransferase or deacetylase activity, have been implicated in several diseases, including pulmonary fibrosis.

METHODS

A cross-sectional, prospective, observational single-center study was conducted to investigate the potential role of serum SIRTs levels as biomarkers in patients with IPF. Demographic, clinical, and functional data and serological samples were collected from 34 patients with IPF followed at the Interstital Lung and Rare Diseases Outpatient Clinic of the Vanvitelli Pneumology Clinic, Monaldi Hospital, Naples, Italy and from 19 age-matched controls.

RESULTS

Serum SIRT-1 levels were significantly reduced in IPF patients compared to controls (median IPF 667 [435-858] pg/mL versus controls 925 [794-1173] pg/mL; p < 0.001 ). In contrast, serum SIRT-3 levels were significantly increased in IPF patients compared to controls (median IPF 338 [230-500] pg/mL versus controls 154 [99.8-246] pg/mL; p < 0.001). There were no statistically significant differences in serum SIRT-6 and SIRT-7 levels between IPF and controls. In addition, we found a significant positive correlation between SIRT-1 and lung function parameters such as FEV1% (ϱ=0.417;p = 0.016), FVC% (ϱ=0.449;p = 0.009) and DLCO% (ϱ=0.393;p = 0.024), while a significant negative correlation was demonstrated between SIR-1 and GAP score, demonstrating a significant reduction in SIRT-1 in advanced Gender-Age-Physiology (GAP) stages 2-3 compared to GAP stage 1 (p = 0.008).

CONCLUSIONS

This prospective, cross-sectional study showed that SIRT-1 was associated with lung function and IPF severity and that both SIRT-1 and SIRT-3 could be considered as potential biomarkers of IPF, whereas SIRT-6 and SIRT-7 were not associated with IPF.

Multidisciplinary Approach to the Diagnosis of Idiopathic Interstitial Pneumonias: Focus on the Pathologist's Key Role

Idiopathic Interstitial Pneumonias (IIPs) are a heterogeneous group of the broader category of Interstitial Lung Diseases (ILDs), pathologically characterized by the distortion of lung parenchyma by interstitial inflammation and/or fibrosis. The American Thoracic Society (ATS)/European Respiratory Society (ERS) international multidisciplinary consensus classification of the IIPs was published in 2002 and then updated in 2013, with the authors emphasizing the need for a multidisciplinary approach to the diagnosis of IIPs. The histological evaluation of IIPs is challenging, and different types of IIPs are classically associated with specific histopathological patterns. However, morphological overlaps can be observed, and the same histopathological features can be seen in totally different clinical settings. Therefore, the pathologist's aim is to recognize the pathologic-morphologic pattern of disease in this clinical setting, and only after multi-disciplinary evaluation, if there is concordance between clinical and radiological findings, a definitive diagnosis of specific IIP can be established, allowing the optimal clinical-therapeutic management of the patient.

Pulmonary vascular dysfunction without pulmonary hypertension: A distinct phenotype in idiopathic pulmonary fibrosis

Pulmonary vascular dysfunction in the absence of pulmonary hypertension (PH) has been observed in patients with idiopathic pulmonary fibrosis (IPF). We describe the prevalence and etiology of elevated pulmonary vascular resistance (PVR) without PH among patients with IPF. Hemodynamic, echocardiographic, and functional respiratory imaging (FRI) data was compared between patients with IPF without PH with normal (<3 wood units) and elevated PVR (≥3 wood units). Mortality between these two groups were compared to patients with IPF and PH. Of 205 patients with IPF, there were 146 patients without PH, of whom 114 (78.1%) had a normal PVR and 32 (21.9%) who had a high PVR. Functional testing and hemodynamics were similar in the two groups, except for the cardiac index which was significantly lower in patients with a high PVR (2.3 vs. 2.6 L/min/m2; p = 0.004). Echocardiographic comparison demonstrated a higher tricuspid regurgitant velocity in those with a high PVR (3.4 vs 3.0 m/s; p = 0.046). FRI revealed proportionately fewer large vessels as a proportion of the vasculature in the patients without PH and elevated PVRs. Among patients without PH, PVR was associated with increased mortality. In conclusion, patients with IPF without PH but a high PVR appear to be a distinct phenotype with a prognosis between those with and without PH, likely reflecting the continuum of vascular dysfunction. The basis for this unique hemodynamic profile could not be definitively discerned although FRI suggested an aberrant anatomical vascular response.