Reduced glomerular filtration rate defines chronic kidney disease and is associated with cardiovascular and all-cause mortality. We conducted a meta-analysis of genome-wide association studies for estimated glomerular filtration rate (eGFR), combining data across 133,413 individuals with replication in up to 42,166 individuals. We identify 24 new and confirm 29 previously identified loci. Of these 53 loci, nineteen associate with eGFR among individuals with diabetes. Using bioinformatics, we show that identified genes at eGFR loci are enriched for expression in kidney tissues and in pathways relevant for kidney development and transmembrane transporter activity, kidney structure, and regulation of glucose metabolism. Chromatin state mapping and DNase I hypersensitivity analyses across adult tissues demonstrate preferential mapping of associated variants to regulatory regions in kidney but not extra-renal tissues. These findings suggest that genetic determinants of eGFR are mediated largely through direct effects within the kidney and highlight important cell types and biologic pathways.

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Endothelial dysfunction contributes to the increased cardiovascular risk that accompanies CKD. We hypothesized that the soluble VEGF receptor 1 (sFlt-1), a VEGF antagonist, plays a role in endothelial dysfunction and decreased angiogenesis in CKD. We enrolled 130 patients with CKD stages 3 to 5 and 56 age-and gender-matched control patients. Plasma sFlt-1 levels were higher in patients with CKD and, after multivariate regression analyses, exclusively associated with renal function and levels of vWF, a marker of endothelial dysfunction. Compared with serum from control patients, both recombinant sFlt-1 and serum from patients with CKD had antiangiogenic activity in the chick chorioallantoic membrane (CAM) assay, induced endothelial cell apoptosis in vitro, and decreased nitric oxide generation in two different endothelial cell lines. Pretreating the sera with an antibody against sFlt-1 abrogated all of these effects. Furthermore, we observed increased sFlt1 levels in 5/6-nephrectomized rats compared with sham-operated animals. Finally, using real-time PCR and ELISA, we identified monocytes as a possible source of increased sFlt-1 in patients with CKD. Our findings show that excess sFlt-1 associates with endothelial dysfunction in CKD and suggest that increased sFlt-1 may predict cardiovascular risk in CKD.

Abstract-Anomalies in either of the tightly linked genes encoding the enzymes CYP11B1 (11␤-hydroxylase) or CYP11B2 (aldosterone synthase) can lead to important changes in arterial pressure and are responsible for several monogenically inherited forms of hypertension. Mutations in these genes or their regulatory regions could thus contribute to genetic variation in susceptibility to essential hypertension. To test this hypothesis, we performed 2 complementary studies of the CYP11B1/CYP11B2 locus in essential hypertension. After characterizing a DNA contig containing the CYP11B1 gene and mapping the gene in the Centre d'Etudes du Polymorphisme Humain reference panel of families, we performed a linkage study with 292 hypertensive sibling pairs and a highly informative microsatellite marker near CYP11B1. We also analyzed the association of 2 frequent biallelic polymorphisms of the CYP11B2 gene, 1 in the promoter at position Ϫ344 (Ϫ344C/T) and the other, a common gene conversion in intron 2, with hypertension in 380 hypertensive patients and 293 normotensive individuals. Statistical analyses did not show significant linkage of the CYP11B1 microsatellite marker to hypertension. No positive association with hypertension was found with the gene conversion in intron 2, but a positive association with hypertension was found with the Ϫ344T allele. The hypertensive and normotensive samples differed significantly in both genotype (Pϭ0.023) and allele frequencies (Pϭ0.010). Our data suggest a modest contribution of the CYP11B2 gene to essential hypertension. (Hypertension. 1998;32:198-204.)Key Words: aldosterone synthase Ⅲ steroid 11␤-hydroxylase Ⅲ biallelic polymorphism Ⅲ microsatellite marker Ⅲ association study Ⅲ linkage study T he cytochrome P450, CYP11B1, a steroid 11␤-hydroxylase, catalyzes the terminal step of cortisol biosynthesis.

Abstract-The renin-angiotensin-aldosterone system plays an important role in blood pressure regulation by influencing salt-water homeostasis and vascular tone. The purpose of the present study was to search for associations of single nucleotide polymorphisms on 3 major candidate genes of this system with the plasma concentrations of the corresponding renin-angiotensin-aldosterone system components considered as quantitative phenotypes. Genotyping was performed in 114 normotensive subjects for different variants of the angiotensinogen (AGT) gene (C-532T, G-6A, M235T), the angiotensin I-converting enzyme (ACE) gene [4656(CT) 2/3 ], the aldosterone synthase (CYP11B2), and the type 1 angiotensin II receptor (AT1R) gene (A1166C) by hybridization with allele-specific oligonucleotides (ASO) or enzymatic digestion of polymerase chain reaction products. Plasma levels of AGT, ACE, angiotensin II (Ang II), aldosterone, and immunoreactive active renin were measured according to standard techniques. Platelet binding sites for Ang II were analyzed by the binding of radioiodinated Ang II to purified platelets. B max and K D values of the Ang II binding sites on platelets of each individual were calculated to examine a possible relationship between these parameters and the AT1R genotype. A highly significant association of the ACE 4656(CT) 2/3 variant with plasma ACE levels was observed (PϽ0.0001). ANOVA showed a significant effect of the AGT C-532T polymorphism on AGT plasma levels (Pϭ0.017), but no significant effect was detectable with the other AGT polymorphisms tested, such as the G-6A or the M235T. A significant effect association was also found between the C-344T polymorphism of the CYP11B2 gene and plasma aldosterone levels, with the T allele associated with higher levels (Pϭ0.02 Key Words: angiotensinogen Ⅲ angiotensin-converting enzyme Ⅲ angiotensin II Ⅲ aldosterone Ⅲ polymorphism Ⅲ blood pressure S ingle nucleotide biallelic polymorphisms are powerful tools when used to search for a linkage disequilibrium between a marker genotype and a disease, mainly of multifactorial origin. With these markers, candidate genes of the renin-angiotensin-aldosterone system (RAAS), including those of angiotensinogen (AGT), the angiotensin I-converting enzyme (ACE), and type I angiotensin (Ang) II receptor (AT1R), have been investigated in association studies with cardiovascular diseases, such as hypertension or myocardial infarction. As examples of these associations, the ACE insertion/deletion (I/D) polymorphism was found associated with myocardial infarction, cardiac hypertrophy after physical exercise, and Alzheimer disease, 1,2 and the AGT or AT1R genes were found to be associated with hypertension. 3,4 Therefore, it is of interest to establish relationships between these marker genotypes and intermediate phenotypes related to the disease and to the gene tested to understand the physiopathology of these associations, thus helping to clarify inconsistent results issued from some association studies. Among these observations, the st...

Fabry disease (FD) is a progressive multisystemic disorder, treatable with recombinant enzyme replacement therapy (agalsidase). However, recent studies suggest an endogenous inhibition of agalsidase in patients with FD, as reported for other lysosomal storage diseases. To assess the clinical consequences of serum-mediated agalsidase inhibition in affected patients, we determined the agalsidase inhibition status of 168 patients (68 male) with FD and compared outcomes of inhibition-positive patients with those of inhibition-negative patients. The assessment included clinical events during time on agalsidase, determination of renal and cardiac function, and evaluation of FD-related symptoms. The frequency of serum-mediated agalsidase inhibition was 40% in agalsidase-treated males. Inhibition did not depend on the compound initially used (agalsidase-a or -b). Agalsidase inhibition was associated with higher lysoglobotriaosylceramide levels and worse disease severity scores in patients. Compared with agalsidase inhibition-negative men, agalsidase inhibition-positive men showed greater left ventricular mass (P=0.02) and substantially lower renal function (difference in eGFR of about -30 ml/min per 1.73 m 2 ; P=0.04), which was confirmed by a longitudinal 5-year retrospective analysis. Additionally, affected patients presented more often with FD-typical symptoms, such as diarrhea, fatigue, and neuropathic pain, among others. Therefore, patients with poor clinical outcome on agalsidase should be tested for agalsidase inhibition. Future studies are warranted to determine if affected patients with FD benefit from acute reduction of anti-agalsidase antibodies or long-term immune modulation therapies to suppress agalsidase inhibition and to identify mechanisms that minimize antibody generation against agalsidase.

Abstract-The matrix Gla protein (MGP) is an important inhibitor of vessel and cartilage calcification that is strongly expressed in human calcified, atherosclerotic plaques and could modulate plaque calcification and coronary heart disease risk. Using a genetic approach, we explored this possibility by identifying polymorphisms of the MGP gene and testing their possible association with myocardial infarction (MI) and plaque calcification. Eight polymorphisms were identified in the coding and 5Ј-flanking sequences of the MGP gene. All polymorphisms were investigated in 607 patients with MI and 667 control subjects recruited into the ECTIM Study (Etude Cas-Témoins de l'Infarctus du Myocarde) and in 717 healthy individuals with echographically assessed arterial calcification and atherosclerosis who were participating in the AXA Study. In the ECTIM Study, alleles and genotypes were distributed similarly in patients and controls in the whole study group; in only 1 subgroup of subjects defined as being at low risk for MI were the concordant AϪ7 and Ala 83 alleles more frequent in patients with MI than in controls (PϽ0.003). In the AXA Study among subjects with femoral atherosclerosis, the same alleles were more common in the presence than the absence of plaque calcification (PϽ0.025). The other MGP polymorphisms were not associated with any investigated clinical phenotype. Transient transfection experiments with allelic promoter-reporter gene constructs and DNA-protein interaction assays were carried out to assess possible in vitro functionality of the promoter variants detected at positions Ϫ814, Ϫ138, and Ϫ7 relative to the start of transcription. When compared with the Ϫ138 T allele, the minor Ϫ138 C allele consistently conferred a reduced promoter activity of Ϫ20% (PϽ0.0001) in rat vascular smooth muscle cells and of Ϫ50% (PϽ0.004) in a human fibroblast cell line, whereas the other polymorphisms, including Ϫ7, displayed no evidence of in vitro functionality. We conclude that the AϪ7 or Ala 83 alleles of the MGP gene may confer an increased risk of plaque calcification and MI; however, the observed relationships are weak or limited to subgroups of patients and therefore need confirmation. (Arterioscler Thromb Vasc

Despite the important advances that have enabled better stroke prevention in atrial fibrillation (AF) and more effective maintenance of sinus rhythm over the past decades, a large unmet need to improve the prevention and treatment of AF remains. Mortality for AF remains at 3.5% per year, and death is often experienced as sudden death or as a result of heart failure 1,2 . Each year, approximately 20% of patients with AF need to be hospitalized 3,4 , and stroke occurs in 1.5% of patients with AF who are receiving anticoagulant drugs 5 . Furthermore, more than half of the patients with AF are symptomatic despite adequate anticoagulation and rate control 4,6 . In view of the projected increase in the incidence and prevalence of AF 7-9 , as well as the substantial burden of death and dis ability that is still associated with this condition 10 , the status quo is unacceptable.Current management of patients with AF comprises treatment of the accompanying cardiovascular conditions, oral anticoagulation, rate control -with medications that slow atrioventricular nodal recovery or, rarely, with atrioventricular nodal ablation -and rhythm-control therapy with antiarrhythmic drugs, electrical cardioversion, catheter ablation or, at times, AF surgery 11,12 . Unfortunately, most of these current approaches are disconnected from our understanding of the major mechanisms that cause AF 1,13,14 1,2,7,19,20 Abstract | Despite remarkable advances in antiarrhythmic drugs, ablation procedures, and stroke-prevention strategies, atrial fibrillation (AF) remains an important cause of death and disability in middle-aged and elderly individuals. Unstructured management of patients with AF sharply contrasts with our detailed, although incomplete, knowledge of the mechanisms that cause AF and its complications. Altered calcium homeostasis, atrial fibrosis and ageing, ion-channel dysfunction, autonomic imbalance, fat-cell infiltration, and oxidative stress, in addition to a susceptible genetic background, contribute to the promotion, maintenance, and progression of AF. However, clinical management of patients with AF is currently guided by stroke risk parameters, AF pattern, and symptoms. In response to this apparent disconnect between the known pathophysiology of AF and clinical management, we propose a roadmap to develop a set of clinical markers that reflect the major causes of AF in patients. Thereby, the insights into the mechanisms causing AF will be transformed into a format that can underpin future personalized strategies to prevent and treat AF, ultimately informing better patient care.230 | APRIL 2016 | VOLUME 13 www.nature.com/nrcardio CONSENSUS STATEMENT © 2 0 1 6 M a c m i l l a n P u b l i s h e r s L i m i t e d . A l l r i g h t s r e s e r v e d .