The Asp299Gly Toll-like receptor 4 polymorphism in advanced aortic atherosclerosis.

BACKGROUND: Recently, the common Asp299Gly polymorphism of the Toll-like receptor 4 (TLR-4) was found to be associated with a reduced incidence of acute myocardial infarction and carotid atherosclerosis. As TLR-4 signalling is causally involved in atherogenesis, the polymorphism was postulated to impart protection from atherosclerosis. To explore a potential atheroprotective effect, we studied the association between the Asp299Gly polymorphism and atherosclerosis in hypertensive patients undergoing angiography for suspected renovascular disease. METHODS: 140 hypertensive subjects underwent intraarterial digital subtraction angiography, during which the presence of atherosclerotic lesions was assessed at the level of the abdominal aorta and renal arteries. Extensiveness of disease was classified as follows: atherosclerosis confined to the abdominal aorta, unilateral renal artery stenosis or bilateral renal artery stenosis. Subsequently, genotyping for the +896 A>G (Asp299Gly) single nucleotide polymorphism was performed in all patients. In statistical analyses 17 patients were excluded because of incomplete data (n=3) or a diagnosis of fibromuscular disease (n=14). RESULTS: 21 patients were found heterozygous for the 299Gly allele, whereas none of the subjects were 299Gly homozygous (299Gly allele frequency 7.8%). The prevalence of the 299Gly allele in atherosclerotic patients was not different from the prevalence observed in subjects without atherosclerotic lesions (16.9 vs 15.5%, p=0.83). Moreover, 299Gly carriership was not associated with the extensiveness of (advanced) aortic atherosclerosis (p=0.64). CONCLUSION: Our results suggest that the Asp299Gly TLR-4 receptor polymorphism is not associated with the prevalence nor extensiveness of (advanced) aortic atherosclerosis.

C-reactive protein, atherosclerosis and kidney function in hypertensive patients.

Previous studies have shown a relationship between coronary or carotid atherosclerosis and C-reactive protein (CRP) concentrations. In the present investigation, we evaluated the relationship between high-sensitivity CRP (hsCRP) concentrations and the presence of atherosclerotic lesions in the renal arteries and/or abdominal aorta. In 95 hypertensive patients who underwent intra-arterial DSA on suspicion of renovascular disease, blood was sampled during the procedure for measurement of hsCRP. The presence of atherosclerotic lesions was assessed at the level of the renal arteries and the abdominal aorta. Haemodynamically significant renal artery stenosis was diagnosed when 50% or more stenosis was observed. Patients with fibromuscular disease (n = 8) or incomplete data (n = 4) were excluded from analysis. The results revealed that the median hsCRP concentrations were significantly higher among the 57 patients with atherosclerosis of the aorta and/or renal arteries compared to those in the 26 patients without any angiographic lesions (4.6 vs 1.7 mg/l; P < 0.005). Moreover, in patients with renal artery stenosis, levels of hsCRP were higher when the degree of stenosis exceeded 50%. However, the association between hsCRP and the presence of atherosclerosis appeared to be confounded by serum creatinine, creatinine clearance, age and gender. In the whole group a significant inverse relationship was found between creatinine clearance and hsCRP (P < 0.05). In conclusion, hsCRP concentrations are related to atherosclerotic lesions in the renal arteries and the abdominal aorta. While this supports the view that atherosclerotic renal artery stenosis is part of a systemic inflammatory vascular disease, increased concentrations of CRP may also coincide with decreased renal function.