Plasma Lipoprotein(a) and its relationship with disease activity in patients with Behçet's disease

Arterial distensibility in chronic inflammatory rheumatic disorders

The pulse wave velocity (PWV), as an indicator of arterial distensibility, may play an important role in the stratification of patients based on the cardiovascular risk. PWV inversely correlates with arterial distensibility and relative arterial compliance. Decreased arterial distensibility alters arterial blood pressure and flow dynamics, and disturbes coronary perfusion. Systemic immune and inflammatory diseases, such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) are associated with increased morbidity and mortality, predominantly due to adverse cardiovascular events. Systemic inflammation in these disorders may alter arterial compliance and arterial distensibility and, through this effect, lead to accelerated atherosclerosis. We have demonstrated an increase in the carotid-femoral (aortic) PWV that is a technique in which large artery elasticity is assessed from analysis of the peripheral arterial waveform, in patients with chronic inflammatory conditions such as RA, SLE, familial Mediterranean fever (FMF), Wegener's granulomatosis (WG), sarcoidosis, psoriasis and psoriatic arthritis except Behçet's disease (BD). In this review, the issue of arterial stiffness in RA, SLE, as well as WG, psoriasis, FMF, BD, sarcoidosis, systemic sclerosis (SS) and Takayasu's arteritis (TA) is overviewed.

Serum paraoxonase activity is decreased in the active stage of Behçet's disease

AIMS

To evaluate paraoxonase1 (PON1) activities and malondialdehyde (MDA) levels, one of the end products of lipid peroxidation induced by reactive oxygen species in patients with Behçet's disease (BD) in the active stage.

METHODS

Serum MDA levels and PON1 levels were measured spectrophotometrically in 16 patients with BD in the active stage of the disease and in 15 healthy subjects who constituted the control group.

RESULTS

In the BD group, median (range) serum PON1 and MDA levels were 149.64 U/l (88.02-281.68) and 1.21 nmol/ml (0.90-3.42), respectively. In the control group, median (range) serum PON1 and MDA levels were 206.86 U/l (114.43-422.52) and 0.72 nmol/ml (0.50-1.12), respectively. There was a statistically significant decrease in serum PON1 levels (p = 0.02) and an increase in serum MDA levels (p<0.001) in patients with BD in the active stage when compared to controls.

CONCLUSION

Endothelial damage and increased polymorph nuclear leucocyte activity in the active stage of BD could result in a pro-oxidation environment which, in turn, results in decreased antioxidant PON activity and increased lipid peroxidation as evidenced by increased MDA levels.

Adenosine deaminase enzyme activity is increased and negatively correlates with catalase, superoxide dismutase and glutathione peroxidase in patients with Behçet's disease: original contributions/clinical and laboratory investigations

AIM

Behçet's disease (BD) is an inflammatory vasculitis with immunologic, endothelial and neutrophil alterations. Adenosine deaminase (AD) is a marker of T-cell activation and is related to the production of reactive oxygen species by neutrophils with the production of NO(*), O(2)(*-), H(2)O(2) and OH(*). We reported increased tumour necrosis factor-alpha, soluble interleukin-2 receptor, interleukin-6, interleukin-8 and NO(*) in active BD. As there is a relation between cytokines, T cells and oxidative stress in inflammatory diseases, this study further evaluated: (1) plasma AD activity and its correlation with acute phase reactants; (2) thiobarbituric acid-reactive substances (TBARS) as an indicator for lipid peroxidation; and (3) antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSHPx) and catalase in patients with BD. The effect of disease activity and correlations between the measured parameters were explored.

METHODS

A total of 35 active (n=17) or inactive (n=18) patients with BD (16 men, 19 women) satisfying International Study Group criteria, and 20 age-matched and sex-matched controls (nine men, 11 women) were included in this cross-sectional case-control study. AD and TBARS were measured in plasma, catalase in red blood cells (RBC), and SOD and GSHPx in both plasma and RBC in both groups. Acute phase reactants (alpha(1)-antitrypsin, alpha(2)-macroglobulin, neutrophils, erythrocyte sedimentation rate) were used to classify patients as active or inactive.

RESULTS

Plasma AD (mean+/-standard error of the mean, 36.1+/-0.7 U/l) and TBARS (4.2+/-0.1 nmol/ml) levels were significantly (for each, p<0.001) higher in BD than in controls (24.1+/-0.8 U/l and 1.6+/-0.1 nmol/ml, respectively). RBC catalase activity was significantly (p<0.001) lower in BD than in controls (120.9+/-3.8 versus 160.3+/-4.1 k/g haemoglobin). SOD and GSHPx activities were significantly lower in both plasma and erythrocytes of patients with BD than in controls (plasma SOD, 442.4+/-8.6 versus 636.4+/-9.2 U/ml, p<0.001; RBC SOD, 3719.2+/-66.0 versus 4849.7+/-49.0 U/g haemoglobin, p<0.001; plasma GSHPx, 73.1+/-1.5 versus 90.6+/-2.9 U/ml, p<0.001; RBC GSHPx, 600.7+/-8.0 versus 670.6+/-10.1 U/g haemoglobin, p<0.001). Active BD patients had significantly lower antioxidant enzymes (except RBC catalase) and higher AD and TBARS levels than inactive subjects (for each, p<0.01). When considering all BD patients, a significant positive correlation was present between AD and TBARS (p<0.001) whereas both AD and TBARS were negatively correlated with antioxidant enzymes (for each, p<0.05).

CONCLUSIONS

AD and lipid peroxidation are increased and associated with defective antioxidants in BD, suggesting interactions between activated T cells and neutrophil hyperfunction. Measures of pro-oxidative stress and antioxidative defence with AD activity as an indicator of T-cell activation can be considered as significant supportive diagnostic indicators, especially in active disease. In addition, strengthening the antioxidant defence may contribute to treatment modalities.

Plasma apolipoprotein(a) co-deposits with fibrin in inflammatory arthritic joints

Extravascular coagulation and diminished fibrinolysis are processes that contribute to the pathology of both inflammatory arthritis and atherosclerosis. We hypothesized that, given its homology with plasminogen, apolipoprotein (apo) (a), the distinctive glycoprotein of the atherogenic lipoprotein (Lp) (a), may be equally implicated in inflammatory arthritis. We detected the presence of apo(a) as part of Lp(a) in human arthritic synovial fluid. The abundance of apo(a) in synovial fluid rose in proportion to plasma apo(a) levels and was higher in inflammatory arthritides than in osteoarthritis. In addition, apo(a) immunoreactive material, but not apo(a) transcripts, was detected in inflammatory arthritic synovial tissues. These data indicated that synovial fluid apo(a) originates from circulating Lp(a) and that diffusion of Lp(a) through synovial tissue is facilitated in inflammatory types of arthritis. In synovial tissues, apo(a) co-localized with fibrin. These observations could be reproduced in a model of antigen-induced arthritis, using transgenic mice expressing human Lp(a). Although in this mouse model the presence of apo(a) did not change the severity of arthritis, the co-localization of apo(a) with fibrin in synovial tissue suggests that, in humans, apo(a) may modulate locally the fibrinolytic activity and may thus contribute to the persistence of intra-articular fibrin in inflammatory arthritis.

Relationship between lipid peroxidation and disease activity in patients with Behçet's disease

Behçet's disease is a chronic multi-systemic disorder which is characterized by a relapsing systemic inflammatory process. The alteration of lipid profile and lipid peroxidation resulting from the inflammatory process may he associated with an increased risk for atherosclerosis in patients with Behcet's disease. We investigated lipids, lipoprotein and lipid peroxidation and their inter-relationships considering the disease activity. Eighteen patients (11 male and 7 female) and 20 age-matched healthy subjects (10 male and 10 female) were studied. Lipid profile including total cholesterol, triacylglycerol, HDL-cholesterol, LDL-cholesterol, lipoprotein(a), apoAI and apoB, and acute phase reactants including polymorphonuclear (PMN) elastase, PMN leukocyte count, erythrocyte sedimentation rate (ESR) and complements (C3, C4) were evaluated in patients in active and inactive periods of Behçet's disease and control subjects. The levels of thiobarbituric acid reactive substance (TBARS) were assessed as an indicator of lipid peroxidation. Lipid peroxidation was found to he increased in the active period compared to the inactive period of the disease and control subjects. Also, lipid peroxidation showed correlations of various degrees with atherogenic lipid parameters in both periods of the followed-up patients. In conclusion, patients with Behçet's disease in the active period may be much more susceptible to atherogenic events than those in the inactive period of the disease and control subjects.