Adipokines in interstitial lung diseases

Exploring the role of serum adiponectin and its holigomerization in fibrotic interstitial lung diseases: results from a cross-sectional study

Intestitial lung diseases (ILDs) include a group of inflammatory and fibrotic pulmonary disorders with different etiologies which in several patients might lead to a progressive reduction of respiratory capacities and chronic respiratory failure. Nowadays, biomarkers for predicting the ILD progression and response to therapies are lacking. Adiponectin, the most abundant peptide secreted by adipocytes, has emerged as a potential response biomarker in fibrotic progressive ILDs. The aim of this observational prospective single-center cross-sectional study is therefore to verify whether serum adiponectin levels were altered in patients with fibrotic ILDs (f-ILDs) and its correlation with clinical and pulmonary function data. Sixty-four f-ILDs patients - divided in three subgroups IPF, CTD-ILDs and other f-ILDs - and 45 healthy subjects were recruited. Serum adiponectin concentration were measured by enzyme-linked immunosorbent assay (ELISA). Pulmonary function tests and clinical data were systematically collected. The results showed that patients with f-ILDs have reduced circulating levels of serum adiponectin (12.5 [10.8-15.4] versus 19.3 [17.3-20.8] p < 0.001). No significant difference in adiponectin levels were observed in the different f-ILDs subgroups (p = 0.619). Adiponectin levels were not associated with progression of f-ILDs (p = 0.745). High molecular weight adiponectin isoform was highly reduced in patients with f-ILDs. In patients with CTD-ILDs - but not in other subgroups - adiponectin levels were associated with pulmonary function and GAP index. These resuls support a potential role of adiponectin as diagnostic and prognostic biomarker of f-ILDs.

The predictive effects of adiponectin and irisin hormones on diagnosis and clinical involvement of Sarcoidosis

BACKGROUND

Sarcoidosis is a chronic disease of unknown etiology characterised by systemic non-caseating granulomas that can affect any organ in the body, especially the lungs and in which genetic and environmental factors are thought to play a role in its pathophysiology. Adipokines and myokines secreted from adipose and muscle tissue play a role in the pathogenesis or protection against many inflammatory and autoimmune diseases in which inflammation and immunity form the basis. In our study, we aimed to investigate the role of the irisin and adiponectin in sarcoidosis.

METHODS

The study included 90 sarcoidosis patients and 86 healthy subjects. Adiponectin and irisin levels were analysed in addition to standard tests for diagnosis and follow-up of patients with sarcoidosis. The sensitivity and specificity of serum irisin levels for the diagnosis of sarcoidosis were evaluate dusing ROC analysis.

RESULTS

Irisin levels were significantly lower in the patient group than in the control group (3.28-5.25, p < 0.001). There was no association between irisin levels and extrapulmonary involvement. The cut-off irisin value for the diagnosis of sarcoidosis was ≤ 4.2662 with 95% confidence interval, and the sensitivity and specificity were calculated as 84% and 55.8%, respectively.

CONCLUSIONS

To our knowledge, this is the first study to investigate irisin in sarcoidosis patients. Based on the available evidence, anti-inflammatory, anti-oxidant and anti-apoptocic effects of irisin may play a role in the pathophysiology of sarcoidosis. Although no significant difference was found in our study, we believe that a comprehensive evaluation of adiponectin in sarcoidosis is important.

The association between adipokines and pulmonary diseases: a mendelian randomization study

BACKGROUND

The role of adipokines in the development of lung diseases is significant, yet their specific relationship with different lung diseases remains unclear.

METHODS

In our research, we analyzed genetic variations associated with adipokines and various lung conditions such as interstitial lung disease, chronic obstructive pulmonary disease, asthma, lung cancer, sleep apnea, pneumonia, and tuberculosis, using data from public genome-wide studies. We employed Mendelian randomization techniques, including inverse variance weighting, weighted median, and MR-Egger regression methods, and conducted sensitivity checks to validate our findings.

RESULTS

A study using the FinnGen database, which included 198,955 participants, identified 13 SNPs associated with adiponectin. Notably, adiponectin was found to significantly reduce the risk of interstitial lung disease and idiopathic pulmonary fibrosis. However, little evidence was found to establish a direct cause-effect relationship between the six adipokines and several other lung conditions, including sarcoidosis, asthma, chronic obstructive pulmonary disease, lung cancer, tuberculosis, pneumonia, and sleep apnea syndrome.

CONCLUSION

This study reveals a reverse link between adiponectin levels and the likelihood of interstitial lung disease, including idiopathic pulmonary fibrosis.

Linking Adiposity to Interstitial Lung Disease: The Role of the Dysfunctional Adipocyte and Inflammation

Adipose tissue has functions beyond its principal functions in energy storage, including endocrine and immune functions. When faced with a surplus of energy, the functions of adipose tissue expand by mechanisms that can be both adaptive and detrimental. These detrimental adipose tissue functions can alter normal hormonal signaling and promote local and systemic inflammation with wide-ranging consequences. Although the mechanisms by which adipose tissue triggers metabolic dysfunction and local inflammation have been well described, little is known about the relationship between adiposity and the pathogenesis of chronic lung conditions, such as interstitial lung disease (ILD). In this review, we detail the conditions and mechanisms by which adipose tissue becomes dysfunctional and relate this dysfunction to inflammatory changes observed in various forms of ILD. Finally, we review the existing basic and clinical science literature linking adiposity to ILD, highlighting the need for additional research on the mechanisms of adipocyte-mediated inflammation in ILD and its clinical implications.