Toll-like receptor (TLR)-9 promotor polymorphisms and atherosclerosis.

BACKGROUND: Currently, the primary cause of atherosclerosis remains controversial: while oxidized or enzymatically altered LDL is widely accepted as one cause of the inflamed lesion, microorganisms such as C. pneumoniae or cytomegalovirus (CMV) also have recently been postulated to be involved in the pathogenesis of atherosclerosis. Microbial products activate innate immune cells of the host via Toll-like receptors (TLRs). Common polymorphisms of the TLR-2 and TLR-4 genes have been shown to be associated with an increased risk for restenosis after PTCA, and a lower risk of carotid atherosclerosis, respectively. Microbial DNA has been shown to activate immune cells via the cytosolic TLR-9. Specially, C. pneumonia and CMV as intracellular pathogens may be potent trigger of TLR-9 signaling. Therefore, we investigated whether the two common promotor polymorphisms of the TLR-9 gene are correlated with atherogenesis. METHODS: The T-1237C and the T-1486C polymorphisms were analyzed by Real Time PCR in 202 (derivation study, age 58.1, SD 10.0) and 182 (validation study, age 59.7, SD 9.6) patients that underwent angioplasty and 188 healthy controls (age 52.5, SD 6.1). Restenosis was defined as >50% luminal diameter reduction at follow-up angiography. RESULTS: We found the two polymorphism being able to create new potential binding sites for transcription factors, however, no association of the TLR-9 polymorphisms with atherogenesis or restenosis was detectable. CONCLUSION: Our data indicate that the two TLR-9 promotor polymorphisms are not involved in atherogenesis.

A frequent toll-like receptor (TLR)-2 polymorphism is a risk factor for coronary restenosis.

Restenosis is a major problem for patients undergoing percutaneous transluminal coronary angioplasty (PTCA). Inflammatory processes and genetic factors have been suggested to be involved in the pathogenesis of both atherosclerosis and restenosis. The recently discovered family of Toll-like receptors (TLRs) consists of molecules that initiate signaling after host-pathogen interactions. Recently it has been shown that the TLRs are involved in the development and progression of atherosclerosis by interfering with lipid metabolisms and by mediating inflammation. TLR-2 is a key innate immunity receptor for sensing both endogenous inflammatory mediators and ligands of several microbial pathogens postulated to be involved in atherosclerosis. A frequent single nucleotide polymorphism (SNP) for the TLR-2 gene, resulting in a non-functional receptor, has been described. By genotyping two independent groups of patients receiving PTCA, followed by stent implantation in one group, we found a significantly enhanced frequency of the TLR-2 Arg753Gln SNP in patients with restenosis as compared to those without restenosis (PTCA: 7.21 versus 2.45%, P = 0.014; PTCA/stent: 6.86 versus 1.53%, P = 0.013). In contrast, a common TLR-4 SNP was similarly distributed among the patient groups investigated. We furthermore compared the frequency of both SNPs in the patients with an age-matched group of individuals without atherosclerosis and found a trend towards a lower frequency of the TLR-4 SNP in the atherosclerotic group (PTCA: 5.58; PTCA/stent: 3.85 versus 7.14%). We conclude that in restenosis a functional TLR-2 is protective and potentially involved in a reaction pattern preventing restenosis. Screening for the TLR-2 Arg753Gln SNP may be of importance for stratifying a patient's risk and for preventive and therapeutic measures.

The microsatellite polymorphism of heme oxygenase-1 is associated with baseline plasma IL-6 level but not with restenosis after coronary in-stenting.

BACKGROUND: Vascular smooth muscle cells (VSMCs) can express heme-oxygenase (HO), a rate-limiting enzyme in the degradation of heme to bilirubin, ferritin and carbon monoxide (CO). VSMC-derived CO can suppress VSMC proliferation and may serve as an antiproliferation factor. The promoter region of HO-1 shows a polymorphism with different (GT) n repeats that has been reported to differently induce gene expression. The objective of this study was to examine the effect of this variation on the occurrence of restenosis after in-stent treatment in patients with coronary artery disease. METHODS: Candidates who underwent coronary stent implantation were genotyped for the HO-1 promoter polymorphism using polymerase chain reaction (PCR) and automated DNA capillary sequencer. Serum levels of IL-6 and C-reactive protein (CRP) were obtained at baseline, 24 hours and 48 hours after stenting. The primary end point for the study was angiographic evidence of in-stent restenosis at 6 months. All parameters for evaluation of restenosis were analysed by quantitative computer-assisted angiographic analysis (QCA). RESULTS: One hundred and eighty-seven patients who underwent coronary stent implantation were studied of whom 27.8% showed > or = 50% restenosis after 6 months. The distribution of (GT) n repeats of all patients in the promoter region of HO-1 genotype ranged from 22 to 42, with (GT) 25 and (GT) 32 being the two most common alleles. The allelic repeats were divided into the short class (S) with 29 (GT) n, the middle class (M) with 30-37 (GT) n and the long class (L) with 38 (GT) n. There was no significant difference in the restenosis between the genotype groups or between post operation levels of inflammation markers, but carriers of the S allele (n = 120) had 33.3% lower baseline IL-6 compared with non-S carriers (n = 67, P = 0.0008). CONCLUSIONS: Although no association was observed between the HO-1 promoter polymorphism and coronary in-stent restenosis following the stent procedure, the association with plasma IL-6 levels suggests that HO-1 S allele might protect from the atherosclerotic inflammatory process.

Rapid and inexpensive real-time PCR for genotyping functional polymorphisms within the Toll-like receptor -2, -4, and -9 genes.

The discovery of the human Toll-like receptors (TLRs) and the recognition of their pivotal role in sensing microbial pathogens during the last 5 years have resulted in a renewed appreciation of innate immunity. Due to their central role in both, triggering innate immunity as well as linking innate and adaptive immunity, genetic variations within the TLR genes, known to be associated with a variety of infectious diseases, are currently of great interest. Several single nucleotide polymorphisms (SNPs) within TLR genes have been described and seem to be associated with susceptibility to inflammatory diseases. However, methods for genotyping SNPs within the TLR genes, e.g. direct sequencing or polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) analysis, are time-consuming. In this work, we report novel real-time PCR methods for genotyping five TLR SNPs within TLR-2, TLR-4 and TLR-9 that have been associated with various diseases using fluorescence labeled hybridization probes and the LightCycler instrument. In addition, we provide protocols employing a standard Taq polymerase in order to reduce substantially the costs for real-time PCR.

A comparison of the radial and the femoral approaches in primary or rescue percutaneous coronary intervention for acute myocardial infarction in the elderly.

BACKGROUND: Access site complications are reduced using radial percutaneous coronary intervention (PCI). There is concern that technical difficulties using this approach can delay achievement of reperfusion during primary or rescue PCI for acute myocardial infarction (AMI) especially in elderly patients. METHODS AND RESULTS: We studied 155 patients (pts) > or = 70 years who underwent primary or rescue PCI for AMI; radial (Group1; 87 pts) or femoral (Group2; 68 pts). Baseline characteristics, the amount of IIB/IIIA inhibitor, contrast and heparin used, and TIMI flow pre and post PCI were similar in both groups (P>0.05). Time from arrival in the catheterization laboratory to the first balloon inflation (Group 1: 44.0+/-21.5 versus Group 2 38.8+/-18.7 min) was also similar, but was significantly longer (61.2+/-11.1 min) compared to both groups in patients with a failed radial approach (7 pts, 8%). Angiographic success, and in-hospital MACE were also similar in the two groups, but vascular access site complications were significantly higher in Group 2 (0 versus 2.9%, P<0.05). CONCLUSION: The use of the radial approach in elderly patients undergoing primary and rescue PCI, when successful, is safe and effective as the femoral approach, and leads to fewer vascular complications.