Parasympathetic activity increases with digital microvascular damage and vascular endothelial growth factor in systemic sclerosis.

Objectives: The imbalance between angiogenic and angiostatic factors with derangement of the microvasculature are hallmarks of systemic sclerosis (SSc). Raynaud's phenomenon in SSc probably is due to the impaired neuroendothelial control mechanisms between vasoconstriction and vasodilatation. The aim of this study is to evaluate autonomic nervous system function using heart rate variability (HRV) analysis and to correlate with vascular endothelial growth factor (VEGF).

Methods: Twenty-seven SSc patients were enrolled. HRV was measured and markers of global sympathetic and parasympathetic system, respectively standard deviation of normal-to-normal RR intervals (SDNN) and square root of the mean of the sum of the squares of differences between adjacent NN intervals (RMSSD) were evaluated. Serum VEGF levels and nailfold videocapillaroscopy (NVC) were performed.

Results: A linear positive correlation was observed between RMSSD and VEGF (p<0.01, r=0.55), and RMSSD and disease duration (p< 0.01, r=0.54). The RMSSD median value was significantly increased (p< 0.05) with NVC damage progression. The RMSSD median value was significantly (p<0.05) higher in SSc patients with digital ulcers (DUs) than in SSc patients without DUs [44 (39.4-60.2) vs 24.6 (23-37.1)].

Conclusions: In our study parasympathetic modulation increases in relation to VEGF. When microcirculation is modified with capillaroscopic pattern progression and DUs, autonomic system seems to stimulate vasodilatation trough parasympathetic system. We can conclude that parasympathetic activity increases with digital microvascular damage and promotes VEGF release.