Coagulation factor XIII, endothelial damage and systemic sclerosis

In the blood coagulation process, Factor XIII (F XIII) is responsible for the stabilization of the fibrin clot. The hypothesized ability of this blood coagulation factor to affect collagen synthesis and degradation led to its use in the treatment of scleroderma. However, the complex mechanism of action of F XIII remains unclear. The aim of our study was to assess possible effects of F XIII on endothelial damage, regarded as an early pathogenic event in systemic sclerosis (SSc). Thus, we measured plasma levels of von Willebrand factor antigen (vWF:Ag), a marker of endothelial cell injury, in 22 patients with SSc, 9 of whom were treated with F XIII and 13 who do not receive the drug. The plasma concentration of F XIII has also been analyzed. Interestingly, the vWF:Ag plasma levels within the group of SSc patients treated with F XIII were significantly lower than those of untreated SSc individuals (p <0.02). On the other hand, the highest mean value of vWF:Ag was found in a subset of untreated subjects having SSc with severe lung involvement, supporting a strict relationship between elevated levels of vWF:Ag and severity of the disease. In contrast, plasma concentration of F XIII resulted normal in all but 3 SSc patients, ruling out a deficiency of this blood coagulation factor as promoting the occurrence of SSc. These preliminary findings seem to support the hypothesis that F XIII may play an improving role on endothelial damage, other than the initially suggested action on collagen metabolism, in SSc.