Background Although elevated plasma levels of homocysteine (Hcy) are considered a risk factor for vascular events, it is still uncertain if the lowering of Hcy by folate restores endothelial function.

Objectives We evaluated the relationship between Hcy and endothelial damage in systemic sclerosis (SSc), measuring plasma levels of von Willebrand factor (vWf), a well accepted marker of endothelial dysfunction, and Hcy, after treatment with PGE1, which has no known interferences with Hcy metabolism and whose long-term benefit is thought to be due to improvement of endothelial function.

Methods Sixty mcg PGE1 (alprostadil alpha-cyclodextrine) in 250 ml 0.9% saline daily were infused daily for a 5 days-period (1st cycle), and after 1 and 2 months for 1 day-period thereafter (2nd and 3rd cycle, respectively) to 10 SSc patients (2 with the diffuse, dSSc, 7 with the limited type, lSSc, 1 with SSc sine scleroderma. Hcy (immunoassay), vWf (ELISA) and folic acid (radioassay) were measured before each cycle.

Results Hcy was reduced vs baseline before the 2nd and 3rd cycle (11.30 ± 3.23 and 12.16 ± 4.86 vs 14.46 ± 5.31 mcM/L, p < 0.005 and p = 0.0616, respectively; mean ± SD), with a percent decrease vs baseline significantly greater in dSSc vs lSSc (66.0 ± 9.7 vs 83.1 ± 7.0%, p < 0.03 and 64.2 ± 14.5 vs 88.4 ± 6.0%, p < 0.05, 2nd and 3rd cycles). vWf was also reduced (167 ± 39 and 156 ± 27 vs 183 ± 12 U/dl, p < 0.05), with no differences between lSSc or dSSc. Folic acid did not change (4.68 ± 1.56, 4.94 ± 2.09 and 4.54 ± 1.71 ng/ml). No relationship was observed between Hcy and vWf.

Conclusion These data are consistent with Hcy as a marker rather than a risk for endothelial damage. Further studies are however needed to evaluate the relatioship of Hcy and vWf plasma levels with endothelial function.