Factor V Leiden, mild hyperhomocyst(e)inemia and Buerger's disease

Homozygous Factor V Leiden Thrombophilia in a Patient With Histologically Confirmed Thromboangiitis Obliterans

Thromboangiitis obliterans (TAO) is a vasculitis characterised by segmental occlusions of small to medium-sized arteries and superficial veins, and a curious predilection for young male smokers. The exact aetiology remains unknown. Current theories postulate it is an autoimmune endarteritis, triggered by some constituent of tobacco and occurring in genetically susceptible individuals. The disease can pose a diagnostic challenge, requiring a high degree of clinical suspicion, particularly in male smokers aged between 20-45 presenting with peripheral ischaemia. The fundamental principle of management is absolute tobacco abstinence. In this article, we report the case of a 27-year-old man who presented with infected, chronic wounds of his upper and lower extremities. He was initially treated with antibiotics and surgical debridement. Unfortunately he went on to develop a protracted course of complications due to poor wound healing ultimately leading to amputation of several digits. A diagnosis of TAO was suspected, and this was later confirmed histologically. Incidentally and of note, the patient was also found to be homozygous for factor V Leiden. An association between TAO and hypercoagulable states, specifically heterozygous factor V Leiden mutation, has been previously described. It is unclear if a synergistic effect between TAO and homozygosity for factor V Leiden may have contributed to the severity and unremitting nature of our patient’s symptoms. We present this case in order to highlight the importance of early recognition of the condition and the need to offer comprehensive smoking cessation support in order to prevent amputation and other complications of poor wound healing.

[Buerger's disease or thromboangiitis obliterans]

The Buerger's disease or thromboangiitis obliterants (TAO) is a non atheromatous inflammatory disease which alters medium and small-sized arteries and veins. It can be found world-wide, but it is more frequent in Eastern Europe, Middle East, Asia and Southeast Asia. Young men and smokers are the most affected. The incidence of this disease is increasing among women. The cause of this disease is unknown yet. The most striking fact is the relationship between TAO and tobacco. The diagnostic is most often late in front of a digital leg ischemia. Complementary exams help to its diagnostic and management but none of them are specific out of the pathology. The affection is evolving towards distal gangrene with amputation in 5 to 10% of cases. Prostacyclin demonstrated its efficiency. Revascularization surgery is difficult but sometimes possible. Sympathectomy, medular stimulation must be suggested. The patient survival is not at stake and the prognosis is above all functional. The most important element in the treatment is stop smoking definitively.

The role of prothrombotic mutations in patients with Buerger's disease

Thromboangiitis obliterans (TAO), or Buerger's disease, is a segmental occlusive inflammatory disorder of the arteries and veins, and etiopathogenesis is still obscure. In the present study we investigated the prevalence of prothrombin 20210 G-->A, factor V 1691 G-->A (Factor V Leiden), and factor V 4070 A-->G (His 1299 Arg) mutations, found to be associated with increased risk for vascular thrombosis, in 36 patients with TAO. We performed a case-control study of these mutations. The odds ratio for prothrombin 20210 A allele compared with G allele was 7.98 (95% confidence intervals 2. 45-25.93). Only this prothrombotic genetic factor was associated with the risk of TAO (p=0.032). In conclusion, carrying the prothrombin 20210 G-->A may be an important prothrombotic risk factor of TAO. This genetic predisposition must be screened in these patients routinely, and clinical importance must be supported by further investigations.

Comparative methodologic study of NFkappaB activation in cultured endothelial cells

The transcriptional regulatory protein nuclear factor kappaB (NFkappaB) participates in the control of gene expression of many modulators of the inflammatory and immune responses. Various activators trigger NFkappaB release and nuclear translocation after phosphorylation and proteolytic degradation of IkappaB. This study evaluated the abilities of fluorescence and confocal microscopies, laser scanning cytometry (LSC), electrophoretic mobility-shift assay (EMSA), and Western blotting to detect NFkappaB activation in endothelial cells (ECs) and to investigate the role of homocysteine (Hcy) in NFkappaB activation. ECs were treated with interleukin-1B (10 ng/mL) or Hcy thiolactone (1 and 5 mmol/L) as NFkappaB activators. Hcy, a thiol-containing amino acid, has been shown to directly damage ECs in vitro. Experimental evidence suggests that the atherogenic propensity associated with hyperhomocysteinemia results from EC dysfunction. When ECs were pretreated with an inhibitor (pyrrolidine dithiocarbamate, 100 micromol/L) or with staurosporine (5 microL/mL), no NFkappaB activation was observed. NFkappaB activation in ECs could be detected with all five techniques, clearly showing NFkappaB translocation from the cytoplasm to the nuclei. Confocal microscopy was more sensitive and less subjective than immunofluorescence microscopy. LSC was even more sensitive, specific, and reproducible. EMSA, the reference method, has the disadvantages of being radioactive, expensive, and time consuming. Western blot analysis detected the NFkappaB p50 subunit implicated in NFkappaB activation. The techniques usually used to detect NFkappaB activation in ECs are immunofluorescence microscopy and confocal microscopy, LSC, EMSA, and Western blot analysis, but none of them is ready for routine use.