Biomedical subjects

Markus Exner

Publications and source records attributed to Markus Exner.

At least 19 recordsLinked to original sources

PubMed2006

The dietary soy flavonoid genistein abrogates tissue factor induction in endothelial cells induced by the atherogenic oxidized phospholipid oxPAPC.

INTRODUCTION: Tissue factor (TF) plays a pivotal role in the generation of thrombin in atherothrombotic disease. The oxidized phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (oxPAPC), an active compound of minimally oxidized low-density lipoprotein (MM-LDL), induces TF in endothelial cells (EC). The dietary soybean isoflavonoid genistein has been claimed to reverse several processes leading to atherosclerosis and related cardiovascular events via binding to estrogen receptors, generating nitric oxide (NO) or inhibiting tyrosine kinase-dependent pathways. METHODS AND MATERIALS: The effects and mechanisms of genistein on activity, antigen expression and mRNA levels of oxPAPC-induced TF were studied in human umbilical vein endothelial cells (HUVEC) and human aortic endothelial cells (HAEC). RESULTS AND CONCLUSIONS: Genistein abrogated oxPAPC-induced TF activity in arterial and venous human EC to basal levels, as measured by functional clotting assay, and downregulated oxPAPC-induced antigen expression measured by flow cytometry and mRNA levels quantified by real-time PCR. Western blotting and inhibitor experiments with the estrogen-receptor inhibitor ICI 182,780 and the NO-synthase inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) showed that the effect may be mediated via inhibition of phosphorylation of ERK, but not upstream MEK1/2. The effect is not mediated by the tyrosine kinase inhibitor activity of genistein, as another tyrosine kinase inhibitor (tyrphostin 25) had no effect. Binding to the estrogen receptor or generation of NO are not involved in the action of genistein on TF. In conclusion genistein reduces oxPAPC-induced TF expression and thereby the prothrombotic phenotype of EC, further substantiating and explaining the beneficial effects of dietary genistein in preventing atherosclerosis and related cardiovascular events.

Anticoagulants↗

PubMed2006

A microsatellite polymorphism in the heme oxygenase-1 gene promoter is associated with risk for melanoma.

Heme oxygenase-1 (HO-1) has been demonstrated to play an important role in the regulation of signaling systems, which are involved in the control of cell cycle progression and apoptosis. Recently, a (GT)n dinucleotide repeat polymorphism in the HO-1 promoter was shown to modulate HO-1 gene expression. Short (<25 GT) repeats are associated with an increased HO-1 upregulation after stimulation than are longer repeats. Malignant melanoma (MM) is the most serious cutaneous malignancy with high tendency to aggressive growth and resistance to apoptosis. Therefore, we sought to study the influence of this polymorphism on the progression of MM. We determined the HO-1 promoter genotype in 152 patients with MM and 398 healthy controls and studied their association in regard to susceptibility to MM, Breslow thickness and disease-free survival. In our study, the homozygous short allele with <25 (GT)n repeats (S/S) was found more frequently in the melanoma group compared to the healthy control population (21 and 12%, respectively). The calculated risk for acquiring primary MM in S/S carriers was 2-fold higher compared to those with L-allele types (95% confidence interval: 1.2-2.4, p = 0.03). Additionally, the S/S genotype was significantly associated with primary tumors with deeper Breslow thickness compared to L-allele (>25 repeats) carriers (mean Breslow thickness: 4.0 +/- 2.9 mm versus 3.1 +/- 1.7 mm, p = 0.03). These data suggest that HO-1 might render a higher risk for MM in S/S genotype individuals and could represent an important candidate gene in the pathogenesis and growth of malignant melanoma.

Alleles↗

PubMed2006

Asymmetric dimethylarginine predicts major adverse cardiovascular events in patients with advanced peripheral artery disease.

OBJECTIVE: Circulating concentrations of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthesis, are elevated in conditions associated with increased cardiovascular risk. We investigated whether elevated ADMA concentrations predict major adverse cardiovascular events (MACE) in patients with advanced peripheral artery disease (PAD). METHODS AND RESULTS: We prospectively enrolled 496 of 533 consecutive patients with PAD (median age 70 years, 279 males). ADMA and L-arginine were assessed at baseline by high performance liquid chromatography. The occurrence of MACE (myocardial infarction, percutaneous coronary intervention, coronary artery bypass graft, stroke, carotid revascularization, death) was evaluated during a follow-up of median 19 months (interquartile range 11 to 25). One hundred eighty-two MACE were observed in 141 patients (28%). MACE occurred in 39% of the patients in the highest quartile and 26% of those in the lowest quartile of ADMA (P=0.016, log-rank test for all quartiles). Adjusted hazard ratios for occurrence of MACE for increasing quartiles of ADMA compared with the lowest quartile were 0.87 (95% confidence interval [CI], 0.51 to 1.48), 1.12 (95% CI, 0.62 to 1.90), and 1.70 (95% CI, 1.02 to 2.88), respectively. We observed no association between cardiovascular outcome and L-arginine. CONCLUSIONS: High ADMA plasma concentrations independently predict MACE in patients with advanced PAD. This indicates that ADMA may be a new cardiovascular risk marker in these patients.

Aged↗

PubMed2006

Dental and periodontal status and risk for progression of carotid atherosclerosis: the inflammation and carotid artery risk for atherosclerosis study dental substudy.

BACKGROUND AND PURPOSE: Dental and periodontal disease are potentially involved in the pathogenesis of atherosclerosis. We investigated whether dental and periodontal status is associated with the presence and future progression of carotid stenosis. METHODS: We randomly selected 411 of 1268 participants from the prospective Inflammation and Carotid Artery Risk for Atherosclerosis Study and evaluated dental and periodontal status and oral hygiene at baseline measuring three World Health Organization-validated indices: DMFT (decayed, missing, filled teeth), SLI (Silness-Löe Index), and CPITN (community periodontal index for treatment needs), respectively. The degree of carotid stenosis was measured by duplex ultrasound at baseline and after median 7.5 months (range=6 to 9 months) to identify patients with progressive carotid stenosis. RESULTS: DMFT (P<0.01), SLI (P=0.048), CPITN (P=0.007), and edentulousness (P=0.007) were associated with the baseline degree of carotid stenosis. Atherosclerosis progression was observed in 48 of 411 patients (11.7%). DMFT (adjusted odds ratio [OR]=1.11, 95% CI=1.01 to 1.22, P=0.032) and SLI (adjusted OR=1.77, 95% CI=1.09 to 2.79, P=0.021), but not CPITN (adjusted OR=1.51, 95% CI=0.89 to 2.45, P=0.16) were significant predictors of disease progression, irrespective of traditional cardiovascular risk factors and the baseline degree of stenosis. Edentulous patients had a significantly increased risk for disease progression as compared with patients with teeth (adjusted OR=2.10, 95% CI=1.06 to 4.16, P=0.33). CONCLUSIONS: Dental status, oral hygiene, and particularly tooth loss are associated with the degree of carotid stenosis and predict future progression of the disease.

Aged↗

PubMed2006

Myeloperoxidase predicts progression of carotid stenosis in states of low high-density lipoprotein cholesterol.

OBJECTIVES: We investigated the effect of myeloperoxidase (MPO) on progression of carotid stenosis in states of high and low high-density lipoprotein-cholesterol (HDL-C) and low-density lipoprotein-cholesterol (LDL-C) levels. BACKGROUND: Myeloperoxidase is pivotally involved in the pathogenesis of atherosclerosis. In vitro data suggest that MPO exerts deleterious effects via oxidative modulation of lipoproteins. METHODS: We prospectively studied 1,019 of 1,268 consecutive patients who were asymptomatic with respect to carotid artery disease. Patients underwent serial carotid ultrasound investigations at baseline and after a follow-up interval of median 7.5 months (range 6 to 9 months), categorizing carotid arteries as 0% to 29%, 30% to 49%, 50% to 69%, 70% to 89%, or 90% to 99% stenosed or occluded. The MPO, HDL-C, and LDL-C levels were measured at baseline, grouped by medians, and correlated with progression of carotid atherosclerosis. RESULTS: Progression of carotid atherosclerosis was found in 100 of 1,019 patients (9.8%). Myeloperoxidase (p = 0.014) but not HDL-C (p = 0.95) or LDL-C (p = 0.30) were associated with progressive disease. However, MPO > or =310 ng/ml was significantly associated with progressive disease (adjusted odds ratio [OR] 2.57, 95% confidence interval [CI] 1.39 to 4.75) only in patients with HDL-C levels <49 mg/dl. Otherwise, in patients with higher HDL-C levels (> or =49 mg/dl), MPO > or =310 ng/ml did not predict disease progression (adjusted OR 1.42, 95% CI 0.72 to 2.78). No interaction of MPO with LDL-C was observed. CONCLUSIONS: Myeloperoxidase was associated with progression of carotid atherosclerosis in patients with HDL cholesterol levels below 49 mg/dl.

Aged↗

PubMed2006

Anti-inflammatory mechanisms of the Tibetan herbal preparation Padma 28 in the vessel wall.

BACKGROUND: The Tibetan herbal preparation Padma 28 has been shown to act as an anti-atherosclerotic agent in advanced peripheral arterial occlusive disease. We tested the effect of aqueous Padma 28 extracts on both the Creactive protein (CRP) induced expression of the pro-inflammatory cell adhesion molecule E-selectin and the anti-atherosclerotic protective enzyme heme oxygenase- 1 (HO-1) in human aortic endothelial cells. METHODS AND RESULTS: According to FACS analysis, quantitative RT-PCR and Western blot, CRP-induced E-selectin expression was completely prevented by aqueous Padma 28 extracts. Additionally, Padma 28 mediated an up to 60-fold upregulation of HO-1 mRNA as measured by quantitative RT-PCR. This upregulation could also be demonstrated on the protein level. CONCLUSION: Aqueous extracts of the Tibetan herbal preparation Padma 28 inhibit CRP-induced expression of the inflammatory cell adhesion molecule E-selectin and lead to upregulation of the vascular protective enzyme HO-1 in human aortic endothelial cells. These properties may be responsible for its anti-atherosclerotic effects in peripheral arterial occlusive disease.

Anti-Inflammatory Agents↗

PubMed2006

Products of the reaction of HOCl with tryptophan protect LDL from atherogenic modification.

Hypochlorite (HOCl) attacks amino acid residues in LDL making the particle atherogenic. Tryptophan is prone to free radical reactions and modification by HOCl. We hypothesized, that free tryptophan may quench the HOCl attack therefore protecting LDL. Free tryptophan inhibits LDL apoprotein modification and lipid oxidation. Tryptophan-HOCl metabolites associate with LDL reducing its oxidizability initiated by endothelial cells, Cu(2+) and peroxyl radicals. One tryptophan-HOCl metabolite was identified as 4-methyl-carbostyril which showed antioxidative activity when present during Cu(2+) mediated lipid oxidation, but did not associate with LDL. Indole-3-acetaldehyde, a decomposition product of tryptophan chloramine (the product of the tryptophan-HOCl reaction) was found to associate with LDL increasing its resistance to oxidation. Myeloperoxidase treatment of LDL in the presence of chloride, H(2)O(2) and tryptophan protected the lipoprotein from subsequent cell-mediated oxidation. We conclude that, in vivo, the activated myeloperoxidase system can generate antioxidative metabolites from tryptophan by the reaction of hypochlorite with this essential amino acid.

Acetaldehyde↗

PubMed2006

Rescue therapy with tacrolimus and mycophenolate mofetil does not prevent deterioration of graft function in C4d-positive chronic allograft nephropathy.

BACKGROUND: Humoral alloresponses may contribute to chronic allograft nephropathy (CAN) in a subset of kidney transplant recipients. For chronic humoral rejection, the efficacy of rescue therapy with tacrolimus and mycophenolate mofetil has been suggested. METHODS: Eleven recipients with C4d-positive CAN (index biopsy performed after a median of 3 years posttransplantation), who had been on cyclosporine A-based immunosuppression, were converted to tacrolimus, and if not part of basal therapy, to mycophenolate mofetil. We evaluated the effect of this tacrolimus/mycophenolate mofetil rescue therapy on clinical outcomes and on alloantibody formation detected with flow cytometric testing of panel-reactive antibody. RESULTS: Tacrolimus/mycophenolate mofetil rescue therapy (plus anti-rejection treatment in six recipients with additional signs of acute cellular rejection) failed to prevent progressive deterioration of graft function. Four patients returned to dialysis after 4 to 18 months. Serial post-transplant serology detected HLA class I and/or II reactivity in seven recipients. Tacrolimus/mycophenolate mofetil therapy did not affect the time course of alloantibody levels. One patient with C4d-positive transplant glomerulopathy, who did not respond to tacrolimus/mycophenolate mofetil rescue therapy, developed nephrotic-range proteinuria associated with a rapid decline of allograft function. Despite considerable reduction in alloantibody levels and nearly complete clearance of C4d deposits, immunoadsorption failed to prevent graft failure in this patient. CONCLUSION: Our data argue against the efficacy of tacrolimus/mycophenolate mofetil rescue therapy in established C4d-positive chronic allograft dysfunction. Prospective trials are needed to evaluate whether early initiation of this or other antihumoral strategies are capable of effectively preventing alloantibody-mediated chronic graft injury.

Adult↗

PubMed2006

C4d in pediatric renal allograft biopsies: a marker for negative outcome in steroid-resistant rejection.

Recently, deposition of C4d, reflecting complement activation via the classical pathway, has been established as marker of antibody-mediated rejection. As C4d can be detected in paraffin sections, it allows for retrospective analysis in populations with low case loads, such as in pediatric transplantation. In this study we re-evaluated consecutive renal transplant biopsies obtained since 1990 in 36 children (18 boys, 18 girls) who had received their allograft (nine living, 27 cadaveric) at an age of 10.12+/-4.4 yr. Clinical indications for biopsy were 16 acute steroid resistant rejections (ASRs), 11 chronic rejections and nine other diagnoses. Overall, C4d deposition was found in nine cases (25%), eight of them with diagnosed ASR. Six out of these eight allografts were lost during 36 months of clinical follow-up, a significantly higher rate than in C4d-negative biopsies (p<0.05). C4d status therefore turned out to be an excellent predictor for inferior graft survival following ASR. None of the other histopathologic markers were sensitive for humoral rejections. In conclusion, the high prevalence of C4d-positive staining in ASR demonstrates the importance of the humoral part of the immune system in pediatric transplantation. The worse outcome of C4d-positive rejections despite massive immunosuppressive therapy clearly indicates the need for innovative therapies in this high-risk population.

Biomarkers↗

PubMed2006

Prediction of iatrogenic pseudoaneurysm after percutaneous endovascular procedures.

PURPOSE: To prospectively evaluate the accuracy of using physical examination to identify puncture-related groin pseudoaneurysms, as assessed by using duplex ultrasonography (US), after percutaneous transluminal procedures and to prospectively evaluate the association between preinterventional platelet count, antiplatelet medication, and the occurrence of pseudoaneurysms. MATERIALS AND METHODS: This study was approved by the local ethics committee, and informed consent was obtained from all patients. The study prospectively included 273 consecutive patients (161 men, 112 women; age range, 34-90 years) who were referred for duplex US evaluation of the inguinal arterial puncture site 1 day after endovascular procedures. Prior to duplex US, all patients underwent physical examination of the groin. In addition, clinical characteristics and preinterventional laboratory parameters were assessed. Statistical significance was determined by using chi2 tests, the Fischer exact test, and unpaired t tests. RESULTS: Twenty-three pseudoaneurysms were found in 273 patients by using duplex US. Pulsatile groin masses that were detected at physical examination were used to correctly identify all pseudoaneurysms (positive predictive value, 100%; negative predictive value, 100%). Painful pulse palpation had a slightly lower predictive power (positive predictive value, 92% [95% confidence interval: 81%, 100%]; negative predictive value, 100% [95% confidence interval: 100%, 100%]). Other clinical parameters, such as the presence of superficial hematomas, systolic bruits, or nonpulsatile groin masses, had no adequate predictive properties. Interobserver agreement was excellent between observers (97% agreement [95% confidence interval: 92%, 100%]). All patients with pseudoaneurysms had a preprocedural platelet count of less than 200 x 10(9)/L. No subacute complications were observed at the access site in patients with a platelet count of more than 200 x 10(9)/L. CONCLUSION: Physical examination revealed sufficient predictive capability in facilitating the identification of iatrogenic pseudoaneurysms after percutaneous vascular procedures. A platelet count of less than 200 x 10(9)/L was associated with high predictive capability, thereby warranting further assessment in a larger series of patient.

Adult↗

PubMed2005

Analysis of sequence variations in the ABCC6 gene among patients with abdominal aortic aneurysm and pseudoxanthoma elasticum.

Abdominal aortic aneurysm (AAA) is characterized by dilatation of arterial walls, which is accompanied by degradation of elastin and collagen molecules. Biochemical and environmental factors are known to be relevant for AAA development, and familial predisposition is well recognized. A connective tissue disorder that is also associated with fragmentation of elastic fibers is Pseudoxanthoma elasticum (PXE). PXE is caused by mutations in the ABCC6 gene and mainly affects dermal, ocular and all vascular tissues. To investigate whether variations in ABCC6 are found in AAA patients and to determine mutations in PXE patients, we analyzed seven selected ABCC6 exons of 133 AAA and 54 PXE patients subjected to mutational analysis. In our cohort of AAA patients, we found five ABCC6 alterations, which result in missense or silent amino acid variants. The allelic frequencies of these sequence variations were not significantly different between AAA patients and healthy controls. Therefore, we suggest that alterations in ABCC6 are not a genetic risk factor for AAA. Mutational screening of the PXE patients revealed 19 different ABCC6 variations, including two novel PXE-causing mutations. These results expand the ABCC6 mutation database in PXE.

Adult↗

PubMed2005

Preoperative antithrombin III activity predicts outcome after surgical repair of acute type A aortic dissection.

BACKGROUND: Acute Stanford type A aortic dissection is associated with substantial perioperative morbidity and mortality. A sepsis-like state may lead to antithrombin (AT) III consumption and deficiency. The impact of preoperative AT III activity on outcome in patients undergoing emergency surgery is yet unknown. METHODS: We measured preoperative AT III activity in 99 consecutive patients undergoing emergency aortic surgery for Stanford type A aortic dissection during a 4-year period in a retrospective study. Cardiovascular co-morbidities, risk factors and surgical data were recorded and patients were followed for 30-day mortality, and occurrence of multiple organ failure (MOF). RESULTS: During the first 30 days, 15 patients (15%) died, and 8 patients (8%) had MOF. Median AT III levels (IQR) in 30-day non-survivors versus survivors were 64% (52-72) versus 90% (75-97) (p<0.001), and in patients with versus without MOF were 66% (52.3-77.3) versus 88% (72-96) (p=0.018), respectively. Adjusted odds ratios for 30-day mortality and MOF for AT III activity (per % increments) were 0.92 (p=0.007), and 0.96 (p=0.012), respectively, indicating a significant inverse relationship between AT III activity and outcome. CONCLUSION: There is a strong inverse association between preoperative AT III activity and adverse outcome in patients undergoing surgical repair of acute Stanford type A aortic dissection. Larger studies are necessary to determine a cut-off value for AT III and to assess whether patients with low AT III levels benefit targeted therapeutic interventions.

Adult↗

PubMed2005

Association of a functional polymorphism in the clopidogrel target receptor gene, P2Y12, and the risk for ischemic cerebrovascular events in patients with peripheral artery disease.

BACKGROUND AND PURPOSE: There is considerable variability in the antiplatelet effects of the thienopyridine agent "clopidogrel." We tested for an association of gene sequence variations in P2Y12 and occurrence of neurological adverse events in patients with symptomatic peripheral artery disease (PAD) during clopidogrel treatment. METHODS: We studied 137 patients undergoing antiplatelet therapy with clopidogrel and 336 patients with aspirin for the occurrence of neurological events (ischemic stroke and/or carotid revascularization). Prevalence of 2 previously described exonic polymorphisms of the P2Y12 gene, 34C>T and 52G>T, was determined by polymerase chain reaction. RESULTS: Genotype frequencies for mutated, heterozygous, and wild-type alleles for the 34C>T and the 52G>T polymorphisms were 9% (n=40), 44% (n=210), and 47% (n=223), and 4% (n=17), 27% (n=127), and 70% (n=329), respectively. During the median follow-up of 21 months, neurological events occurred in 8% of patients. In patients with aspirin therapy, neither polymorphism was associated with neurological events. However, in clopidogrel patients, carriers of at least one 34T allele had a 4.02-fold increased adjusted risk for neurological events compared with carriers of only 34C alleles (95% confidence interval, 1.08 to 14.9). Neither polymorphism was associated with all-cause mortality. CONCLUSIONS: In PAD patients, clopidogrel response variability exists, which may result in increased risk for cerebrovascular events. Sequence alterations of the target receptor gene represent one possible mechanism for clopidogrel failure. Whether identification of the 34C>T polymorphism as a contributor to this process could serve as risk stratification tool, an indicator for higher clopidogrel doses, or the use of alternate agents warrants further investigation.

Aged↗

PubMed2005

Prognostic impact of fibrinogen in carotid atherosclerosis: nonspecific indicator of inflammation or independent predictor of disease progression?

BACKGROUND: Fibrinogen is a key factor in the coagulation cascade, it exhibits proinflammatory properties, and it is suggested to play a pivotal role in atherogenesis. We investigated whether fibrinogen predicts future progression of carotid atherosclerosis, analyzing whether fibrinogen levels add to the prognostic information of other inflammatory parameters. METHODS: We prospectively studied 1268 consecutive patients without recent (12 months) symptoms from cerebrovascular disease. Patients underwent serial ultrasound investigations in 6- to 9-month intervals, categorizing carotid arteries as 0% to 29%, 30% to 49%, 50% to 69%, 70% to 89%, or 90% to 99% stenosed, or occluded. Fibrinogen levels were determined at baseline and follow-up. The risk for progressive carotid atherosclerosis according to fibrinogen levels was calculated, adjusting for traditional risk factors and other inflammatory parameters (C-reactive protein and serum amyloid A). RESULTS: Progression of carotid atherosclerosis was found in 117 of 1268 patients (9.2%) after a median of 8 months (range 6 to 18). Adjusted hazard ratios for atherosclerosis progression with increasing quartiles of baseline fibrinogen were 1.83 (P=0.037), 2.09 (P=0.008), and 2.45 (P=0.002), respectively, compared with the lowest quartile. Fibrinogen at follow-up also was associated with progressive disease (P=0.004). However, additionally adjusting for other inflammatory parameters diminished these associations to a nonsignificant level. CONCLUSIONS: Elevated fibrinogen, reflecting the level of inflammatory activity, is associated with progression of carotid atherosclerosis, as it was demonstrated previously for other inflammatory parameters. However, this association seems to be nonspecifically related to the extent of the inflammatory process in atherosclerotic disease rather than to specific properties of fibrinogen.

Aged↗

PubMed2005

Complement component C5a predicts future cardiovascular events in patients with advanced atherosclerosis.

AIMS: Complement activation occurs in atherosclerotic lesions, and particularly complement component C5a exerts potent chemotactic and proinflammatory effects. However, it is yet unknown, whether plasma levels of C5a may predict cardiovascular risk. The aim of this study was to examine whether plasma levels of the complement component C5a may predict cardiovascular risk in patients with advanced atherosclerosis. METHODS AND RESULTS: We studied 173 patients with symptomatic peripheral artery disease (median age 72, 82 male). Cardiovascular risk profile, levels of the complement factor C5a, and other non-specific inflammatory parameters [high sensitivity C-reactive protein, serum amyloid A (SAA), and fibrinogen] were obtained at baseline, and patients were followed for median 22 months [interquartile range (IQR) 13-27] for the occurrence of major adverse cardiovascular events (MACE: myocardial infarction, percutaneous coronary interventions, coronary artery bypass graft, carotid revascularization, stroke, and death). We observed 65 MACE in 49 patients (28%). Cumulative event rates (95% confidence interval (CI)) within quartiles of C5a at 24 months were 16 (5-27), 26 (13-39), 36 (21-51), and 37% (23-51), respectively (P=0.0077). Adjusted hazard ratios for the occurrence of a first MACE according to increasing quartiles of C5a were 1.81, 2.23, and 2.66, respectively, as compared to the lowest quartile (P=0.038), irrespective of the level of other inflammatory parameters. CONCLUSION: Complement activation, indicated by the elevation of C5a, seems to be associated with increased cardiovascular risk in patients with advanced atherosclerosis. Clinically, determination of C5a may add to the predictive value of other non-specific inflammatory parameters.

Aged↗

PubMed2005

Inflammation and Carotid Artery--Risk for Atherosclerosis Study (ICARAS).

BACKGROUND: Compelling evidence suggests that inflammation is fundamentally involved in the pathogenesis of atherosclerosis; however, temporal correlation between inflammation and morphological features of atherosclerosis progression has not been demonstrated unequivocally. METHODS AND RESULTS: We prospectively studied 1268 consecutive patients who were initially asymptomatic with respect to carotid artery disease. Patients underwent serial carotid ultrasound investigations at baseline and after a follow-up interval of a median of 7.5 months (range 6 to 9 months), with measurement of carotid flow velocities and categorization of carotid arteries as 0% to 29%, 30% to 49%, 50% to 69%, 70% to 89%, or 90% to 99% stenosed or occluded. High-sensitivity C-reactive protein (hs-CRP) and serum amyloid A (SAA) were measured at baseline and follow-up. Progression of carotid atherosclerosis was found in 103 (8.1%) of 1268 patients. Hs-CRP and SAA, respectively, at baseline (P=0.004 and P=0.014) and follow-up (P<0.001 and P<0.001) and the change from baseline to follow-up (P<0.001 and P<0.001) were significantly associated with progressive atherosclerosis. Adjusted ORs (95% CI) for atherosclerosis progression with increasing quintiles of baseline hs-CRP were 1.65 (0.71 to 3.84), 1.87 (0.8 to 4.37), 3.32 (1.49 to 7.39), and 3.65 (1.65 to 8.08), and with increasing quintiles of baseline SAA, they were 0.86 (0.38 to 1.92), 0.99 (0.49 to 1.99), 1.72 (0.91 to 3.28), and 2.28 (1.24 to 4.20), respectively, compared with the lowest quintiles. CONCLUSIONS: These findings supply evidence for a close temporal correlation between inflammation and morphological features of rapidly progressive carotid atherosclerosis, which suggests that elevation or increase of the inflammatory biomarkers hs-CRP and SAA identifies the presence of active atherosclerotic disease.

Aged↗

PubMed2005

[C4d]FlowPRA screening--a specific assay for selective detection of complement-activating anti-HLA alloantibodies.

On waiting lists, transplant candidates are routinely screened for potentially harmful complement-fixing alloantibodies using complement-dependent cytotoxicity (CDC) panel-reactive antibody (PRA) testing. We have recently developed a novel cell-independent assay for assessment of complement-activating panel reactivity ([C4d]FlowPRA), which is based on selective flow-cytometric detection of alloantibody-triggered C4 complement split product deposition to human leukocyte antigen (HLA)-coated FlowPRA beads. Serum specimens selected from 120 transplant candidates were evaluated by [C4d]FlowPRA (HLA class I vs II) in comparison with FlowPRA IgG alloantibody screening (HLA class I vs II), a method detecting both complement- and noncomplement-activating alloantibodies, and with CDC-PRA on separated T (T-CDC) or B cells (B-CDC, evaluation on platelet-absorbed sera). For each assay, >/=10% PRA reactivity was considered positive. Comparing complement-dependent PRA assays with standard FlowPRA, the specificity calculated for [C4d]FlowPRA (HLA class I: 92%; class II: 100%) was found to be superior to that of CDC testing (T-CDC-PRA: 79%; B-CDC-PRA: 86%). Because noncomplement-activating alloreactivities were not detected for both techniques, low sensitivities were calculated ([C4d]FlowPRA HLA class I: 61%; class II: 31%; T-CDC-PRA: 70%; B-CDC-PRA: 55%). Compared with CDC-PRA, [C4d]FlowPRA gave a high specificity (HLA class I compared with T-CDC: 89%, HLA class II compared with B-CDC: 95%) but, at least in part because of false-positive CDC results, a modest sensitivity (66% and 38%, respectively). For both HLA classes, we found a highly significant association between absolute [C4d]FlowPRA and CDC-PRA levels (p < 0.0001). Our results suggest that detection of C4 split product deposition to FlowPRA beads may represent an attractive HLA-specific and time-effective alternative to CDC-PRA screening.

B-Lymphocytes↗

PubMed2005

PAI-1 4G/5G insertion/deletion promoter polymorphism and microvascular complications in type 2 diabetes mellitus.

BACKGROUND: Plasminogen activator inhibitor-1 (PAI-1) plays an important role in the regulation of fibrinolysis and extracellular matrix turnover. PAI-1 4G/5G insertion/deletion polymorphism in the PAI-1 promoter region has been shown to modulate PAI-1 plasma levels. We investigated the relationship between this polymorphism and the prevalence of diabetic nephropathy and retinopathy in patients with type 2 diabetes in the Austrian population. PATIENTS AND METHODS: 147 consecutive patients with type 2 diabetes mellitus (96 men, 51 women; median age, 65 years; IQR, 59-71) were analyzed for the PAI-1 4G/5G genotype. RESULTS: The genotype distribution in the individuals tested was as follows: 17% (n = 25) 5G/5G, 54% (n = 80) 4G/5G, and 29% (n = 42) 4G/4G. Patients homozygous for allele 4G had a significantly higher risk of diabetic proliferative retinopathy than patients without signs of diabetic retinopathy or nonproliferative retinopathy (OR, 7.3; 95% CI, 1.4-38.8; P = 0.02). No significant associations were observed between the PAI-1 genotype and the presence of albuminuria. CONCLUSION: According to our results, diabetic proliferative retinopathy might be associated with the prevalence of PAI-1 genotype 4G/4G.

Aged↗