Occurrence of the JAK2 V617F mutation in patients with peripheral arterial disease.

The acquired JAK2 V617F mutation is common in patients with myeloproliferative neoplasms. We previously showed that JAK2 V617F is also found in coronary patients, most of them affected by coronary atherosclerosis. Peripheral arterial disease (PAD) is another important manifestation of atherosclerosis. However, prevalence of the JAK2 V617F mutation and its effect on clinical or hematologic characteristics is unknown in PAD patients. In the present study we determined the prevalence of JAK2 V617F in a cohort of 287 patients with sonographically proven PAD and compared mutation frequency with mutational status of 997 healthy people from the KORA F4 study. JAK2 V617F screening and quantification of allele burden in both cohorts was performed with same allele-specific quantitative real-time PCR method. From a total of 287 PAD patients, 9 individuals were tested positive for the JAK2 V617F mutation. One patient showed elevated hemoglobin values, indicating polycythemia vera. Observed JAK2 V617F frequency (3.1%) in PAD patients showed a 5-fold, highly significant increase compared with healthy people (P < 0.001). Furthermore, occurrence of the mutation in PAD patients was significantly decreased in patients using aspirin (P = 0.003). We conclude that the prevalence of JAK2 V617F mutation is significantly increased in PAD patients compared to the general population. Future studies are warranted to confirm our observations and to define the underlying mechanisms behind our findings.

Evaluation of the prevalence and prospective clinical impact of the JAK2 V617F mutation in coronary patients.

The JAK2 V617F mutation is not only found in the majority of patients with myeloproliferative neoplasms (MPN), including essential thrombocythemia (ET), but also has been reported in individuals without overt MPN. A close relation of the JAK2 V617F mutation to atherothrombotic events has been described, at least in patients with MPN. The prevalence of the JAK2 V617F mutation and its clinical impact in coronary patients is unknown. To address this issue, DNA samples from 1,589 subjects undergoing coronary angiography with up to 11 years of follow up were genotyped using allele-specific real-time PCR assays. Prevalence of the JAK2 V617F mutation was 1.32% (n = 21) in coronary patients. Two JAK2 V617F positive patients showed baseline platelet counts indicative for ET and a third patient developed ET during follow up, finally resulting in a percentage of 0.188% of ET cases. This corresponds to an up to fivefold accumulation of ET cases in coronary patients compared with the general population. Our study showed no impact of the JAK2 V617F mutation on future atherothrombotic events or overall survival (HR = 1.04 [0.33-3.27]; P = 0.949 and HR = 0.35 [0.05-2.46]; P = 0.288, respectively). Therefore, our data suggest that JAK2 V617F positive coronary patients are not at increased risk for future atherothrombotic complications. Routine mutation screening in coronary patients is, therefore, not warranted. However, number of ET cases appears to be accumulated in coronary patients. For this reason, we recommend JAK2 V617F testing only in coronary patients showing abnormal blood cell counts for further clarification.

Quantitation of JAK2 V617F Allele Burden by Using the QuantStudio™ 3D Digital PCR System.

The JAK2 V617F mutation is highly prevalent in patients with myeloproliferative neoplasms (MPN). Furthermore, it has been shown that its allelic burden correlates with hematologic characteristics, drug response, and clinical endpoints in MPN patients. Digital PCR is an emerging technology for sensitive mutation detection and quantitation, based on dilution and high-grade partitioning of a sample. Here, we describe the use of the nanofluidic chip-based QuantStudio™ 3D Digital PCR System for quantitation of the JAK2 V617F mutation.

Serum uromodulin is associated with impaired glucose metabolism.

Uromodulin is the most abundant urine protein under physiological conditions. It has recently been described as a serum and plasma marker for kidney disease. Whether uromodulin is associated with impaired glucose metabolism is unknown.We therefore measured serum uromodulin and glucose traits in a cohort of 529 consecutively recruited patients.Serum uromodulin was significantly and inversely correlated with fasting plasma glucose (r = -0.161; P < 0.001), with plasma glucose 2 hours after an oral 75 g glucose challenge (r = -0.158; P = 0.001), and with HbA1c (r = -0.103; P = 0.018). A total of 146 (27.6%) of our patients had type 2 diabetes mellitus (T2DM). Analysis of covariance confirmed that T2DM was an independent determinant of serum uromodulin (F = 5.5, P = 0.020) after multivariate adjustment including hypertension and glomerular filtration rate. Prospectively, uromodulin was lowest in patients with T2DM at baseline, higher in initially nondiabetic subjects who developed diabetes during follow-up (FU) and highest among nondiabetic patients (147.7 ±â€Š69.9 vs 164 ±â€Š67 vs 179.9 ±â€Š82.2 ng/mL, Ptrend < 0.001). Similar results were seen with respect to prediabetes (168.0 ±â€Š81.2 vs 172.8 ±â€Š66.3 vs 188.2 ±â€Š74.0 ng/mL, P = 0.011).We conclude that serum uromodulin is significantly associated with impaired glucose metabolism and the development of prediabetes and diabetes.

High plasma chemerin is associated with renal dysfunction and predictive for cardiovascular events - Insights from phenotype and genotype characterization.

The novel adipokine chemerin, encoded by the RARRES2 gene, has been suggested to be linked to insulin resistance and to the metabolic syndrome (MetS). However, no well-defined cardiovascular profile has been reported and the association with coronary artery disease (CAD) is a matter of debate. Because there is a relation between renal dysfunction and CAD, we analyzed plasma chemerin levels and the estimated glomerular filtration rate (eGFR) in 495 patients undergoing coronary angiography for the evaluation of established or suspected stable CAD. Chemerin levels were higher in patients with Type 2 diabetes mellitus (T2DM, n=111) and the metabolic syndrome (MetS, n=147) than in subjects without T2DM (191.5±72.9 vs. 169.7±64.7ng/ml, p=0.001) or the MetS (201.2±71.0 vs. 163,1ng/ml, p<0.001), but did not differ significantly between patients with significant CAD (n=247) and those without significant CAD (177.1±67.0 vs. 171.7±67.2ng/ml, p=0.193). Analysis of covariance using age, sex, and BMI as covariates showed that chemerin was significantly and independently associated with eGFR (F=49.6, p<0.001). After an 8-year follow-up period, patients with high chemerin levels were more often affected by cardiovascular events (HR=1.72 [95% CI 1.19-2.47], p=0.004), even after appropriate adjustment for age, gender, BMI, as well as eGFR (adjusted HR 1.51 [95% CI 1.03-2.23], p=0.037). Given the cardiometabolic role of chemerin, we also applied a Cardio-Metabo Chip analysis and revealed a genome-wide significant association with SNPs (rs55709438, rs2444030, and rs3098423) located at chromosomal region 15q15-23, which were associated with metabolic traits and eGFR. This study for the first time demonstrates that high chemerin concentrations are significantly associated with renal impairment and predictive of cardiovascular events and that 15q15-23 might have an impact on chemerin levels beyond common genetic variations in RARRES2.

Quercetin Impacts Expression of Metabolism- and Obesity-Associated Genes in SGBS Adipocytes.

Obesity is characterized by the rapid expansion of visceral adipose tissue, resulting in a hypoxic environment in adipose tissue which leads to a profound change of gene expression in adipocytes. As a consequence, there is a dysregulation of metabolism and adipokine secretion in adipose tissue leading to the development of systemic inflammation and finally resulting in the onset of metabolic diseases. The flavonoid quercetin as well as other secondary plant metabolites also referred to as phytochemicals have anti-oxidant, anti-inflammatory, and anti-diabetic effects known to be protective in view of obesity-related-diseases. Nevertheless, its underlying molecular mechanism is still obscure and thus the focus of this study was to explore the influence of quercetin on human SGBS (Simpson Golabi Behmel Syndrome) adipocytes' gene expression. We revealed for the first time that quercetin significantly changed expression of adipokine (Angptl4, adipsin, irisin and PAI-1) and glycolysis-involved (ENO2, PFKP and PFKFB4) genes, and that this effect not only antagonized but in part even overcompensated the effect mediated by hypoxia in adipocytes. Thus, these results are explained by the recently proposed hypothesis that the protective effect of quercetin is not solely due to its free radical-scavenging activity but also to a direct effect on mitochondrial processes, and they demonstrate that quercetin might have the potential to counteract the development of obesity-associated complications.

Confirmation of Host Genetic Determinants in the CFH Region and Susceptibility to Meningococcal Disease in a Central European Study Sample.

BACKGROUND: Invasive meningococcal disease (IMD) is a leading cause of meningitis and severe sepsis in children and adolescents. Genetic factors are important in determining the susceptibility to and outcome of IMD. Recently, a genome-wide association study from the United Kingdom showed significant associations of single-nucleotide polymorphisms within complement factor H (CFH; rs1065489) and in CFH-related protein 3 (rs426736) with susceptibility of IMD. We report data of a genetic replication study in Central European children. METHODS: The study was conducted as a retrospective case-reference study involving 248 patients with confirmed diagnosis of IMD from Austria and Germany and 835 healthy reference individuals from a multicenter German birth cohort. RESULTS: Carriers of the minor alleles of rs1065489 and rs426736 were at lower risk of IMD [allelic odds ratio = 0.60 (0.44-0.82); P = 0.001 and 0.61 (0.45-0.83); P = 0.001]. Also, 2 major haplotypes (GT and TC) derived from the 2 single-nucleotide polymorphisms were significantly associated with IMD (P = 0.001 and P = 0.003, respectively). CONCLUSIONS: The consistency of the results between the genome-wide association study and our study population strengthens the association of CFH polymorphisms to the susceptibility of IMD. Our results support the conclusion that CFH is a critical determinant in acquiring meningococcal disease.

Common single nucleotide polymorphisms at the NPC1L1 gene locus significantly predict cardiovascular risk in coronary patients.

BACKGROUND: Niemann-Pick C1-like 1 (NPC1L1) is involved in dietary cholesterol absorption and is the direct molecular target of the LDL-lowering drug ezetimibe. Recently, genetic variants in NPC1L1 have been associated with the incidence of cardiovascular events, but it remains unclear if the impact of NPC1L1 on cardiovascular risk is dependent on its role in cholesterol absorption. Furthermore, no direct association of genetic variants in NPC1L1 with coronary atherosclerosis has been established. METHODS: To further address these issues, we determined the impact of 34 single nucleotide polymorphisms (SNPs) at the NPC1L1 gene locus on the presence of coronary atherosclerosis and prospectively on future cardiovascular events in a cohort of 984 angiographied Caucasian patients. RESULTS: Out of investigated SNPs, 24 variants were significantly associated with future cardiovascular events. The highest impact was observed for rs55837134 (sex-and age adjusted additive HR = 1.67 [1.28-2.18]; p = 1.3 e-4). Regression analysis conditioned on rs55837134 showed that significant associations between remaining SNPs at the NPC1L1 locus and vascular events did not persist suggesting their dependence on rs55837134. Its significant association remained almost unchanged after further adjustment for total cholesterol, LDL cholesterol, and other cardiovascular risk factors (additive HR = 1.67 [1.28-2.18]; p = 1.7 e-4). In addition, no significant association of investigated NPC1L1 variants with coronary atherosclerosis could be observed, at least after false discovery rate correction. CONCLUSIONS: Genetic variants of NPC1L1, particularly rs55837134, show a predictive impact on cardiovascular events. Further studies to determine the molecular consequences of common genetic variants in NPC1L1 are needed.

Evaluation of BRCA1/2 mutational status among German and Austrian women with triple-negative breast cancer.

PURPOSE: Testing for BRCA1 and BRCA2 mutations in breast cancer patients is used to identify the risk of second primary cancers and the risk of cancer in the patients' family. Women with triple-negative breast cancer (TNBC) are thought to be more likely to be BRCA1/2 mutation carriers, but most national guidelines for genetic testing, including those used in Germany and Austria, do not consider receptor triple negativity. METHODS: We determined the prevalence of BRCA1 and BRCA2 mutations within a cohort of 100 unselected TNBC cases, including patients from Germany and Austria to identify those BRCA-positive patients with a masked family history and who would have been missed due to respective current national guidelines. Double-stranded Sanger sequencing of all exons of BRCA1 and BRCA2, respectively, was performed. RESULTS: We identified a total of 13 deleterious mutations in BRCA1 and a total of four deleterious mutations in BRCA2. The total rate of deleterious BRCA1/2 mutation carriers was 21 % in our cohort. Six novel mutations, including two deleterious mutations, have been identified, which have not been described in public mutation databases so far. According to current German and Austrian national guidelines for genetic testing, 38.1 and 52.4 %, respectively, of BRCA1/2 mutation carriers would have been overlooked. CONCLUSIONS: We conclude that the prevalence of BRCA1 and BRCA2 mutations is high in TNBC patients and that BRCA1/2 mutations are not restricted to young women or patients with a positive family history. Receptor triple negativity should therefore be considered in BRCA1/2 genetic testing guidelines.

Genome-wide association study reveals a polymorphism in the podocyte receptor RANK for the decline of renal function in coronary patients.

Impaired kidney function is a significant health problem and a major concern in clinical routine and is routinely determined by decreased glomerular filtration rate (GFR). In contrast to single assessment of a patients' kidney function providing only limited information on patients' health, serial measurements of GFR clearly improves the validity of diagnosis. The decline of kidney function has recently been reported to be predictive for mortality and vascular events in coronary patients. However, it has not been investigated for genetic association in GWA studies. This study investigates for the first time the association of cardiometabolic polymorphisms with the decline of estimated GFR during a 4 year follow up in 583 coronary patients, using the Cardio-Metabo Chip. We revealed a suggestive association with 3 polymorphisms, surpassing genome-wide significance (p = 4.0 e-7). The top hit rs17069906 (p = 5.6 e-10) is located within the genomic region of RANK, recently demonstrated to be an important player in the adaptive recovery response in podocytes and suggested as a promising therapeutic target in glomerular diseases.

Angiopoietin-like protein 4 significantly predicts future cardiovascular events in coronary patients.

BACKGROUND: Angiopoietin-like protein 4 (ANGPTL4) has been associated with cardiometabolic disorders including dyslipidemia and atherosclerosis in animal studies; in humans, however, its impact on metabolic traits and cardiovascular risk remains unclear. METHODS: We examined the association of plasma ANGPTL4 levels with the metabolic syndrome (harmonized consensus definition), with angiographically determined coronary artery disease (CAD), and with the risk of future cardiovascular events in a cohort of 490 patients undergoing coronary angiography for the evaluation of stable CAD. In addition, we investigated the influence of the tagging single nucleotide polymorphisms (SNPs) rs4076317, rs2278236, rs1044250, and rs11672433 as well as variant rs116843064 (E40K) of the ANGPTL4 gene on cardiovascular risk in a larger sample of 983 angiographied coronary patients including the above mentioned 490 subjects. RESULTS: Plasma ANGPTL4 was significantly higher in patients with the metabolic syndrome than in subjects without the metabolic syndrome (26.0 ± 19.4 ng/ml vs. 22.2 ± 19.7 ng/ml; p = 0.008). No significant association was found between ANGPTL4 and angiographically characterized coronary atherosclerosis. Prospectively, however, plasma ANGPTL4 significantly predicted future cardiovascular events both univariately (HR1.45 [1.16-1.82], p = 0.001) and after adjustment for standard cardiovascular risk factors (1.26 [1.01-1.58]; p = 0.045). Concordantly, rs4076317, rs2278236, and rs1044250 significantly affected the risk of future cardiovascular events (adjusted HRs 0.70 [0.54-0.90]; p = 0.005, 0.76 [0.61-0.94]; p = 0.012, and 1.30 [1.03-1.62]; p = 0.025, respectively). CONCLUSIONS: We conclude that plasma ANGPTL4 levels as well as ANGPTL4 variants significantly predict cardiovascular events independently of conventional cardiovascular risk factors.