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These findings support the concept that genetic susceptibility exists in primary RP. The high prevalence of migraine suggests that primary RP is part of a more widespread disorder of vascular tone. These findings do not suggest that common molecular variants of these candidate genes are involved in primary RP.

Epithelial to mesenchymal transition (EMT) is a process whereby epithelial cells undergo transition to a mesenchymal phenotype and contribute directly to fibrotic disease. Recent studies support a role for EMT in cutaneous fibrotic diseases including scleroderma and hypertrophic scarring, although there is limited data on the cytokines and signalling mechanisms regulating cutaneous EMT. We investigated the ability of TGF-β and TNF-α, both overexpressed in cutaneous scleroderma and central mediators of EMT in other epithelial cell types, to induce EMT in primary keratinocytes and studied the signalling mechanisms regulating this process. TGF-β induced EMT in normal human epidermal keratinocytes (NHEK cells), and this process was enhanced by TNF-α. EMT was characterised by changes in morphology, proteome (down-regulation of E-cadherin and Zo-1 and up-regulation of vimentin and fibronectin), MMP secretion and COL1α1 mRNA expression. TGF-β and TNF-α in combination activated SMAD and p38 signalling in NHEK cells. P38 inhibition with SB203580 partially attenuated EMT, whereas SMAD inhibition using SB431542 significantly inhibited EMT and also reversed established EMT. These data highlight the retained plasticity of adult keratinocytes and support further studies of EMT in clinically relevant in vivo models of cutaneous fibrosis and investigation of SMAD inhibition as a potential therapeutic intervention.

Objective-To determine circulating endothelin-1 levels (ET-1) in patients with primary or secondary associated Raynaud's phenomenon (RP) under resting conditions and in response to cold provocation. Methods-Patients were categorised as primary RP (18) or scleroderma associated RP (14). Finger blood flow was measured by venous occlusion plethysmography at finger temperatures of 32°C and 24°C. Vasospasm was detected as a finger systolic pressure of 0 mm Hg after standardised provocative cooling. Severity of vasospasm was assessed by the level of cooling required to provoke spasm. Plasma ET-1 levels were measured in antecubital blood withdrawn under baseline conditions (finger 32°C) and at the point of vasospasm. Measurements were also made in 19 matched control subjects. Results-Finger blood flow was lower in patients with RP than in controls, with no diVerence between the two RP groups. Vasospasm occurred in all patients with RP but not in any control subjects and a grading system of severity was established. Baseline plasma ET-1 levels were similar in patients with RP and controls. Increases in ET-1 levels at the point of vasospasm in patients or corresponding timepoint in controls were also similar. There was no significant diVerence between the ET-1 levels in the two RP subgroups when the fingers were warm or when vasospasm was present. Conclusions-These results do not support the hypothesis that ET-1 plays a part in the pathogenesis of RP. Objective testing is a useful adjunct to the clinical diagnosis of RP and allows assignment of a severity grade.

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