Increased plasma endothelin-1 and abnormal nailfold capillaroscopic findings in patients with connective tissue diseases

Do, Ju Ho; Kim, Ho Youn

Abstract

BACKGROUND: Since the endothelin-1 may be implicated in the pathogenesis of peripheral vascular diseases associated with connective tissue diseases (CTDs), we examined the plasma endothelin-1 level in association with quantitative nailfold capillaroscopy in patients with CTDs.
METHODS
We investigated 79 patients with connective tissue diseases (54 systemic lupus erythematosus (SLE), 18 systemic sclerosis (SSc), 4 mixed connective tissue disease, 3 polymyositis/dermatomyositis). Plasma samples were obtained and endothelin-1 levels were measured by sandwich enzyme-linked immunosorbent assay. The presence and duration of Raynaud phenomenon as well as nailfold capillaroscopy were evaluated in each patient. To examine the quantitative nailfold capillaroscopy, we measured the length of apical limb width, capillary width and capillary length.
RESULTS
According to the presence or absence of Raynaud phenomenon, there was no statistically increased plasma endothelin-1 level between two groups (2.433 +/- 2.259 pg/mL n=33, vs. 1.905 +/- 1.371 pg/mL n=46, p=non specific). All the SSc patients had Raynaud phenomenon and according to the presence of abnormal capillaroscopic findings, there were increased level of endothelin-1 in abnormal capillaroscopy group compared to normal capillaroscopy group (3.940 +/- 3.335 pg/mL (n=12), vs 1.573 1.006 pg/mL (n=6), p<0.05). As compared quantitative examination of nailfold capillaroscopy with plasma endothelin-1 level, in SSc patients the endothelin-1 level correlated well with the length of apical limb width (r(s)=0.577 p<0.05). In SLE patients the endotheliln-1 level correlated well with the length of apical limb width and capillary width (r(s)=0.425 p<0.01, rs=0.278 p<0.05, respectively).
CONCLUSION
Our data demonstrate that the presence of abnormal capillaroscopic findings reflect increased plasma endothelin-1 level in patients with connective tissue diseases, and quantitative analysis of nailfold capillaroscopy can be useful to predict the disease activity with the evidence of increased plasma endothelin-1.