Some aspects of body thermoregulation, environmental temperature and vascular hypothesis in systemic sclerosis patients.

In line with vascular hypothesis of systemic sclerosis (SSc), it is proposed that visceral Raynaud's phenomenon (RP)/endothelial dysfunction causes severe oxygen supply/consumption imbalance in internal organs, leading to visceral ischemic failure in early SSc, especially with cold environmental temperature (Te) and severe RP. There would also be a decrease in body thermogenesis and a decrease in heat loss caused by chronic visceral ischemia and by systemic vasculopathy, respectively. At any given time, these disorders could produce low core temperature (Tc). Hence, SSc is proposed as a candidate cause of secondary hypothermia. It is suggested that SSc could be an adaptive response in cold Te to systemic endothelial damage with secondary chronic visceral ischemia/slow metabolism. This pathophysiological mechanism is proposed in early visceral failure, prognosis, SSc phenotype according to ethnicity, and other manifestations. The impact of Te and Tc on SSc warrants further investigations.