Body mass index and adipokines/cytokines dysregulation in systemic sclerosis

Body fat has regulatory functions through producing cytokines and adipokines whose role in the pathogenesis of systemic sclerosis (SSc) is currently emerging. Changes in body mass, either over- or underweight, entail a dysregulation of the cytokine/adipokine network that may impact upon SSc disease activity. We evaluated serum levels of adipokines and cytokines in SSc patients and correlated them to clinical features and body mass index (BMI) categories. The study included 89 SSc patients and 26 healthy donors (HD). Serum levels of adiponectin, leptin, resistin, visfatin, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-2, IL-10 and IL-17A were measured by multiplex immunoassay and correlated to BMI and disease-specific features. Student's t-test or analysis of variance (ANOVA) were used for comparisons between groups. Spearman's or Pearson's tests were used for correlation analysis. Serum levels of TNF-α, IL-2, leptin and resistin were significantly higher in SSc than in HD. Leptin levels were significantly higher in interstitial lung disease (ILD)- and pulmonary arterial hypertension (PAH)-SSc subgroups. The highest levels of IL-17A, IL-2, IL-10, leptin and visfatin were detected in SSc patients with obesity (p < 0.01). Conversely, underweight SSc patients showed the highest TNF-α levels (p < 0.05). Adipokines, IL-2, IL-10 and IL-17A were found to be increased in SSc patients with obesity, but whether or not they play a role in the pathogenesis of the disease remains to be investigated. Intriguingly, underweight patients had the highest TNF-α levels, suggesting a potential role of TNF-α in inducing the cachexia observed in long-lasting disease.