Advanced microvascular damage associated with occurrence of sarcopenia in systemic sclerosis patients: results from a retrospective cohort study

Objective. Systemic sclerosis (SSc) is characterised by microvascular inflammatory damage, loss of capillaries and progressive systemic fibrosis. Capillary rarefaction may precede sarcopenia, we therefore evaluated the body composition and occurrence of sarcopenia in SSc patients, in relation to the peripheral microcirculatory status, assessed and scored by nailfold videocapillaroscopy (NVC) patterns, including capillary number count and microangiopathy evolution score (MES). Methods. Body composition and bone mineral density were assessed by Dual x-ray absorptiometry and a dedicated software (GE Lunar, USA) in 43 SSc patients (age 64.1 +/- 11.2 yrs, 83.7% women) affected by limited or diffuse cutaneous (74.4%) according to the 2013 EULAR/ACR criteria and 43 age-matched healthy subjects (HS). Sarcopenia was checked as relative skeletal muscle index (RSMI). Clinical, laboratory, body composition and bone parameters were analysed according to the different NVC patterns and MES. Means were compared by the Student's t-test or by one way analysis of variance; medians were compared by the Kruskall Wallis test; and frequencies by the chi square test. Results. Sarcopenia was found in 23.26% of SSc patients with a prevalence significantly higher than age matched HS (4.65%; p=0.03). Interestingly, SSc patients with "late" NVC pattern showed a significantly higher prevalence of sarcopenia (43.75%) compared to "early" (9.1%) and "active" (12.5%) NVC patterns (p<0.0002). In addition, capillary density was found significantly lower in sarcopenic versus non-sarcopenic patients (4.4 +/- 1.8 vs. 5.8 +/- 2.2, p<0.05). Finally, MES showed significantly most severe score in sarcopenic SSc patients (p<0.001): peripheral blood flow analised in a sample of sarcopenic SSc patients by Laser speckle contrast analysis (LASCA) showed lowest values (p<0.05). Total mass (TM), lean mass (LM), fat mass (FM) and bone mineral content (BMC) values were found significantly lower in sarcopenic SSc patients (p<0.0001, p<0.001, p=0.004, p=0.04, respectively). Conclusion. SSc patients with sarcopenia and altered body composition were found affected by the most severe NVC pattern ("late"), a significantly reduced/altered number of capillaries and microvascular array (MES), suggesting a strong link between severity of local microvascular failure and associated muscle sufferance.