Systemic sclerosis (SSc) encompasses a spectrum of connective tissue disorders of unknown etiology. Whereas the pathological hallmark of SSc is increased synthesis and deposition of extracellular matrix within the skin and internal organs resulting in clinical fibrosis and scarring , the origins of the disease are believed to lie within the microvasculature. More than 90 percent of SSc patients initially present with Raynaud's phenomenon (RP), a disorder defined as episodic vasoconstriction of the microvascula-ture. Although microvascular injury is believed to be one of the key initiating events in SSc pathophysiology, both the root cause of the underlying microvascular injury and the precise cellular and molecular mechanisms by which it gives rise to fibrosis are unknown. Microvascular pericytes reside at the interface between the microvasculature and interstitium and are thus ideally situated to mediate interactions between microvessels and extravascular tissue. Furthermore, pericytes have been identified as mesenchy-mal precursor cells with the ability to transdifferentiate into other mesenchymal cell types including collagen-synthesizing fibroblasts, potentially making them key players in the link between microvascular damage and fibro-sis (Figure 1).
Was this article helpful?