Microvascular involvement in systemic sclerosis: laser Doppler evaluation of reactivity to acetylcholine and sodium nitroprusside by iontophoresis.
OBJECTIVE
To investigate the skin vasodilatory response to iontophoretically applied acetylcholine (Ach), an endothelium dependent vasodilator, and to sodium nitroprusside (SNP), an endothelium independent vasodilator, in patients with systemic sclerosis (SSc).


METHODS
Eleven SSc patients were preliminarily studied (10 females, mean age 40.5; mean disease duration 6.5 years), and 16 age and sex matched control subjects. By means of laser Doppler flowmetry skin blood flow was evaluated at third finger, at baseline, and after postischaemic hyperaemia test and during iontophoretically transcutaneous application of 1% solution of Ach and SNP.


RESULTS
No significant differences in basal skin blood flow were detected between SSc patients and controls. Cutaneous vasodilatory response to ischaemia, Ach, and SNP was significantly less pronounced in SSc patients compared with controls (p < 0.001). Moreover, among SSc patients a lower (p < 0.05) vasodilatory response to Ach compared with ischaemia and SNP was recorded.


CONCLUSIONS
These data confirm a reduction of skin digital vasodilatory reserve in SSc patients and suggest a defect of both endothelial dependent arteriolar relaxation and wall compliance in the pathogenesis of this dysfunction.
La Civita
L
L
Department of Internal Medicine, University of Pisa, Italy.
Rossi
M
M
Vagheggini
G
G
Storino
F A
FA
Credidio
L
L
Pasero
G
G
Giusti
C
C
Ferri
C
C
D000109:Acetylcholine; D000328:Adult; D000704:Analysis of Variance; D004730:Endothelium, Vascular / Q000187:drug effects*; D005260:Female; D006801:Humans; D007478:Iontophoresis; D007511:Ischemia / Q000503:physiopathology; D017078:Laser-Doppler Flowmetry; D008297:Male; D008833:Microcirculation / Q000187:drug effects; D008875:Middle Aged; D009599:Nitroprusside; D012595:Scleroderma, Systemic / Q000503:physiopathology*; D012867:Skin / Q000098:blood supply*; D013268:Stimulation, Chemical; D014664:Vasodilation / Q000187:drug effects*
D009599:Nitroprusside; D000109:Acetylcholine