Pathogenic mechanisms in varicose vein disease: the role of hypoxia and inflammation.

AIMS: Although the aetiology of varicose veins remains unknown, recent studies have focused on endothelial cell integrity and function. Among the regulatory factors of vessel tone, synthesises, pro- and anti-inflammatory, adhesion molecules and the transcription factor hypoxia inducible factor-1 alpha (HIF-1alpha), which are responsible for recruiting leukocytes, are very important. METHODS: Investigation in this study focused on the expression of ICAM-1, E-selectin and HIF-1alpha on endothelial cells using immunostaining and RT-PCR in varicose vein specimens compared with controls. RESULTS: Findings of this study showed alterations of the intima, such as focal intimal discontinuity and denudation of endothelium in varicose veins. Based on data derived from immunostaining and RT-PCR, no major differences were identified between ICAM-1 and E-selectin expression in varicose vein specimens compared with controls. In contrast, immunostaining results identified HIF-1alpha expression in five (5/20) varicose vein specimens, whereas no control saphenous vein specimens expressed HIF-1alpha. CONCLUSIONS: These findings could explain other evidence of hypoxia in varicose veins. Finally, results already obtained in this investigation suggest that the process of pathogenesis of varicose veins is not restricted to the role of adhesion molecules.

Inflammatory profiling of peripheral arterial disease.

The progression of peripheral arterial disease (PAD) is poorly understood but may be caused by an underlying inflammatory dysfunction. This study therefore profiled interleukin (IL)-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-13, anticardiolipin, and anti-beta2-glycoprotein 1 antibody concentrations and characterized patients' inflammatory response in vitro. Patients were classified according to World Health Organization criteria and ankle-brachial pressure index into critical ischemics (n=20), stable claudicants (n=20), and controls (n=20). In vitro studies involved culturing whole blood with RPMI-1640 for 24hr with and without 1 microg/mL lipopolysaccharide and profiling cytokine production. Autoantibody levels were measured using enzyme-linked immunosorbent assays, while cytokine profiles were determined by multiplex immunoassay. Serum IL-6, IL-10, IL-13, and anti-beta2-glycoprotein 1 antibody levels were higher in PAD (p<0.05). In the case of IL-6 and anti-beta2-glycoprotein 1 antibody, levels reflected increasing disease severity (p<0.05). In vitro studies revealed that IL-8 and IL-13 secretory capacities were significantly higher in PAD after 6 hr. However, when these were standardized against patient leukocyte count, cytokine production profiles did not differ. PAD features an increased inflammatory burden irrespective of Th1:Th2 cytokine type; this is more pronounced with increasing disease severity. However, the inflammatory hyperresponsiveness of cultured whole blood from PAD patients probably relates to associated leukocytosis, rather than being attributable to an inherent inflammatory dysfunction.

In situ and in vitro evidence for DCoH/HNF-1 alpha transcription of tyrosinase in human skin melanocytes.

Human epidermal melanocytes hold the full capacity for autocrine de novo synthesis/regulation/recycling of the essential cofactor 6-tetrahydrobiopterin (6BH(4)) for conversion of L-phenylalanine via phenylalanine hydroxylase to L-tyrosine and for production of L-Dopa via tyrosine hydroxylase to initiate both pigmentation and catecholamine synthesis in these neural crest-derived cells. Earlier we have demonstrated pterin-4a-carbinolamine dehydratase (PCD) mRNA and enzyme activities in epidermal melanocytes and keratinocytes. This protein dimerises also the transcription factor hepatocyte nuclear factor 1 (HNF-1), leading to activation of multiple genes. This study demonstrates for the first time DCoH/HNF-1 alpha expression and transcriptional activity in human epidermal melanocytes in vitro and in situ and identified tyrosinase, the key enzyme for pigmentation, as a new transcriptional target. Specific binding of DCoH/HNF-1 complex to the human tyrosinase promoter was confirmed by gel shift analysis. These results provide a novel mechanism in the regulation of skin pigmentation.

Diphencyprone immunotherapy alters anti-hair follicle antibody status in patients with alopecia areata.

Alopecia areata (AA) is a relatively common reversible hair loss disorder usually manifesting as patchy areas of complete hair loss on the scalp and other body parts that can progress to complete loss of all body hair. This condition is now generally assumed to be an autoimmune disease with the hair follicle (HF) as the principal target tissue. AA may be passively transferred by T cells and there is some evidence that serum IgG may also disturb hair cycling. Here, we examine whether the status of anti-HF antibody reactivity is altered during hair regrowth associated with topical immunotherapy using the contact sensitizer diphencyprone. Eleven patients with severe AA of the scalp were treated with diphencyprone on one side of the scalp and serum was obtained from each patient before the start of therapy, after unilateral hair regrowth, during continuing hair regrowth and in some cases after complete and sustained regrowth. The presence and titer of circulating antibodies to HF was assessed by indirect immunofluorescence and immunoblotting analysis. A striking reduction was detected in both the titer and range of HF components/antigens targeted by anti-hair follicle IgG antibodies in those patients that exhibited complete and sustained hair regrowth after DCP-treatment. By contrast, unilateral hair regrowth was associated with no change, or even an increase, in anti-HF antibody titer and reactivity. Therefore we can conclude that the down-regulation of antibody reactivity is likely to be a result rather than the cause of hair regrowth induction by topical immunotherapy. As this immunotherapy is associated with a reduction in the titer/pattern of anti-HF antibodies, these may hold the key to the identity of the HF antigen targets in AA. Moreover, the presence/titer of anti-HF antibodies may be a marker of clinical disease activity or opportunity for spontaneous regrowth.