Increased Serum HMGB-1, ICAM-1 and Metalloproteinase-9 Levels in Buerger's Patients.

BACKGROUND: Thromboangiitis obliterans (TAO), or Buerger's disease, is an inflammatory occlusive disorder that affects the limb arteries of young smokers. In the aetiology of TAO the immune system appears to play a critical role; however, information on the aspects involved in the evolution of vascular tissue inflammation and of this disease are still limited. OBJECTIVE: This study was carried out to investigate HMGB-1 (high mobility group box-1), MMP (matrix metalloproteinase)- 2, MMP-9, MMP-11 and ICAM (intercellular adhesion molecule)-1 circulating levels in subjects with Buerger's disease. METHODS: Between January 2010 and December 2012, eight patients underwent surgical revascularization of the lower limbs and a specimen of the affected arterial wall was obtained for histological confirmation of Buerger's disease. A blood sample was collected on the same day for measuring HMGB-1, MMP-3, MMP-9 and ICAM-1 by western blot analysis. Controls (n=7) were healthy non-smokers. RESULTS: TAO subjects had a significant increase in HMGB-1, MMP-9 and ICAM-1 compared with controls (P<.0001), while no differences were observed in MMP-2 and MMP-11 levels. Histology confirmed a strong inflammatory infiltrate with signs of necrosis in the arterial wall. CONCLUSION: These data suggest a role for HMGB -1 in the vascular lesions associated with TAO, unveiling HMGB-1 as a potential target for treating this rare disease.

Thromboangiitis obliterans successfully treated with phosphodiesterase type 5 inhibitors.

Thromboangiitis obliterans, or Buerger's disease, is a non-atherosclerotic, segmental, inflammatory disease affecting the small- and medium-sized vessels of the distal extremities. Other than discontinuation of tobacco, there is no standard-of-care treatment. Although two randomized trials have demonstrated a role for intravenous iloprost, no oral drug has yet been demonstrated to be effective in treating thromboangiitis obliterans. We present the first three reported cases of thromboangiitis obliterans successfully treated with phosphodiesterase type 5 inhibitors, followed by a discussion of the rationale for the use of these agents in thromboangiitis obliterans.

Imbalanced matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 activities in patients with thromboangiitis obliterans.

The pathogenic mechanisms of thromboangiitis obliterans (TAO) are not entirely known and the imbalance of matrix metalloproteinases (MMPs) plays a role in vascular diseases. We evaluated the MMP-2 and MMP-9 circulating levels and their endogenous tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) in TAO patients with clinical manifestations. The study included 20 TAO patients (n = 10 female, n = 10 male) aged 38-59 years under clinical follow-up. The patients were classified into two groups: (1) TAO former smokers (n = 11) and (2) TAO active smokers (n = 9); the control group included normal volunteer non-smokers (n = 10) and active smokers without peripheral artery disease (n = 10). Patient plasma samples were used to analyze MMP-2 and MMP-9 levels using zymography, and TIMP-1 and TIMP-2 concentrations were determined by enzyme-linked immunosorbent assays. The analysis of MMP-2/TIMP-2 and MMP-9/TIMP-1 ratios (which were used as indices of net MMP-2 and MMP-9 activity, respectively) showed significantly higher MMP-9/TIMP-1 ratios in TAO patients (p < 0.05). We found no significant differences in MMP-2/TIMP-2 ratios (p > 0.05). We found higher MMP-9 levels and decreased levels of TIMP-1 in the TAO groups (active smokers and former smokers), especially in active smokers compared with the other groups (all p < 0.05). MMP-2 and TIMP-2 were not significantly different in patients with TAO as compared to the control group (p > 0.05). In conclusion, our results showed increased MMP-9 and reduced TIMP-1 activity in TAO patients, especially in active smokers compared with non-TAO patients. These data suggest that smoke compounds could activate MMP-9 production or inhibit TIMP-1 activity.

Determination of kininogens levels and kallikrein/kininase II activities in patients with thromboangiitis obliterans.

Some components of the kinin system such as plasma kallikrein levels, the activities of tissue kallikrein (including saliva) and kininase II and the concentrations of kininogen fractions (low-molecular weight/LKg and high-molecular weight/HKg) were evaluated in the plasma of patients with thromboangiitis obliterans (TAO) presenting clinical symptoms of the condition. Twenty TAO were diagnosed by means of the traditional Shionoya and Olin criteria and later classified into non-smokers (n = 11) and active smokers (n = 9). Fifty-three normal, non-smoking/smoking individuals (control) were also studied. Kininogen levels were determined by ELISA; the activities of kallikreins and kininase II were determined using selective substrates. The levels of enzymes (kallikreins and kininase II) and protein (kininogens) were significantly higher in patients with TAO who were active smokers compared to the control groups (no matter whether control individuals were active smokers or non-smokers, P < 0.001 for all comparisons). Interestingly, regardless of the time of disease onset, a significant increase in the levels of these components of the kinin system was also observed in patients when TAO active smokers were compared with TAO ex-smokers (P < 0.01 for all analysed parameters). Activation of the kinin system in patients with TAO may indicate the involvement of vasodilatation in an attempt to control vascular changes, thereby favouring the deposition of immune complexes at the vascular level because of nicotine stimulation. Moreover, our results corroborate the idea that TAO can be an autoimmune disorder with specific mechanisms.

Phosphatidylcholine-specific phospholipase C activity and level increase evidently in thromboangitis obliterans.

Thromboangitis obliterans (TAO) is considered to be an inflammatory disease. Previous research has demonstrated that phosphatidylcholine-specific phospholipase C (PC-PLC) plays critical roles in various inflammatory responses. However, the connection between PC-PLC and TAO is undetermined. Therefore, we sought to investigate whether PC-PLC was implicated in TAO. In our study, there were two groups: TAO group and control group. The PC-PLC activity of serum of two groups (16 TAO patients and 11 controls) was detected by PC-PLC activity assay. The level and distribution of PC-PLC in posterior tibial arteries in seven TAO patients and four controls were detected by immunofluorescence staining method. PC-PLC activity increased greatly in serum of TAO patients. Immunofluorescence analysis also revealed an upregulation of PC-PLC in the vascular endothelium of TAO patients. Our data suggest that PC-PLC activity and level increase obviously in TAO patients. Our study may provide new clues for seeking pathogenesis of TAO. Furthermore, it may bring new insights into clinical diagnosis and treatment of TAO.

Genetic evaluation of the common variant of the endothelial nitric oxide synthase (Glu(298)->

BACKGROUND: Nitric oxide is synthesized by endothelial nitric oxide synthase and plays a key role in adequate endothelial function. An important effect is the reduction of free radicals caused by cigarette smoking, which is the only established risk factor for thromboangiitis obliterans (TAO). In patients with TAO a genetic defect of endothelial nitric oxide synthase may therefore result in deteriorated endothelial function. The aim of our study was to evaluate whether a genetic defect of the common variant of endothelial nitric oxide synthase (Glu(298)-->Asp) can be found in a higher degree in patients with TAO compared to healthy controls. METHODS: We enrolled 42 patients with TAO and 149 healthy subjects. RESULTS: Nineteen patients (45.2%) showed homozygosity for Glu(298) versus 76 (51%) in the control group. The heterozygous status for Glu(298)-->Asp was found among 18 patients (42.9%) compared to 61 (40.9%) members of the control group, which was a nearly equal distribution. Homozygosity for the mutant Asp(298) was slightly elevated in the patient group with 11.9 versus 8.1% in the control group. Allele frequency for Asp(298) was 0.333. CONCLUSIONS: Our data do not show elevated homozygosity for the common variant Glu(298)-->Asp in patients with TAO compared to healthy controls. The limitation of our evaluation is the small number of patients, which is a general problem when evaluating patients with TAO, as this is not a common disease.