Hypertension and renin-angiotensin system blockers are not associated with expression of angiotensin-converting enzyme 2 (ACE2) in the kidney.

AIMS: Angiotensin-converting enzyme 2 (ACE2) is the cellular entry point for severe acute respiratory syndrome coronavirus (SARS-CoV-2)-the cause of coronavirus disease 2019 (COVID-19). However, the effect of renin-angiotensin system (RAS)-inhibition on ACE2 expression in human tissues of key relevance to blood pressure regulation and COVID-19 infection has not previously been reported. METHODS AND RESULTS: We examined how hypertension, its major metabolic co-phenotypes, and antihypertensive medications relate to ACE2 renal expression using information from up to 436 patients whose kidney transcriptomes were characterized by RNA-sequencing. We further validated some of the key observations in other human tissues and/or a controlled experimental model. Our data reveal increasing expression of ACE2 with age in both human lungs and the kidney. We show no association between renal expression of ACE2 and either hypertension or common types of RAS inhibiting drugs. We demonstrate that renal abundance of ACE2 is positively associated with a biochemical index of kidney function and show a strong enrichment for genes responsible for kidney health and disease in ACE2 co-expression analysis. CONCLUSION: Our results indicate that neither hypertension nor antihypertensive treatment is likely to alter the expression of the key entry receptor for SARS-CoV-2 in the human kidney. Our data further suggest that in the absence of SARS-CoV-2 infection, kidney ACE2 is most likely nephro-protective but the age-related increase in its expression within lungs and kidneys may be relevant to the risk of SARS-CoV-2 infection.

Uncovering genetic mechanisms of kidney aging through transcriptomics, genomics, and epigenomics.

Nephrons scar and involute during aging, increasing the risk of chronic kidney disease. Little is known, however, about genetic mechanisms of kidney aging. We sought to define the signatures of age on the renal transcriptome using 563 human kidneys. The initial discovery analysis of 260 kidney transcriptomes from the TRANScriptome of renaL humAn TissuE Study (TRANSLATE) and the Cancer Genome Atlas identified 37 age-associated genes. For 19 of those genes, the association with age was replicated in 303 kidney transcriptomes from the Nephroseq resource. Surveying 42 nonrenal tissues from the Genotype-Tissue Expression project revealed that, for approximately a fifth of the replicated genes, the association with age was kidney-specific. Seventy-three percent of the replicated genes were associated with functional or histological parameters of age-related decline in kidney health, including glomerular filtration rate, glomerulosclerosis, interstitial fibrosis, tubular atrophy, and arterial narrowing. Common genetic variants in four of the age-related genes, namely LYG1, PPP1R3C, LTF and TSPYL5, correlated with the trajectory of age-related changes in their renal expression. Integrative analysis of genomic, epigenomic, and transcriptomic information revealed that the observed age-related decline in renal TSPYL5 expression was determined both genetically and epigenetically. Thus, this study revealed robust molecular signatures of the aging kidney and new regulatory mechanisms of age-related change in the kidney transcriptome.

Renal Mechanisms of Association between Fibroblast Growth Factor 1 and Blood Pressure.

The fibroblast growth factor 1 (FGF1) gene is expressed primarily in the kidney and may contribute to hypertension. However, the biologic mechanisms underlying the association between FGF1 and BP regulation remain unknown. We report that the major allele of FGF1 single nucleotide polymorphism rs152524 was associated in a dose-dependent manner with systolic BP (P = 9.65 × 10(-5)) and diastolic BP (P = 7.61 × 10(-3)) in a meta-analysis of 14,364 individuals and with renal expression of FGF1 mRNA in 126 human kidneys (P=9.0 × 10(-3)). Next-generation RNA sequencing revealed that upregulated renal expression of FGF1 or of each of the three FGF1 mRNA isoforms individually was associated with higher BP. FGF1-stratified coexpression analysis in two separate collections of human kidneys identified 126 FGF1 partner mRNAs, of which 71 and 63 showed at least nominal association with systolic and diastolic BP, respectively. Of those mRNAs, seven mRNAs in five genes (MME, PTPRO, REN, SLC12A3, and WNK1) had strong prior annotation to BP or hypertension. MME, which encodes an enzyme that degrades circulating natriuretic peptides, showed the strongest differential coexpression with FGF1 between hypertensive and normotensive kidneys. Furthermore, higher level of renal FGF1 expression was associated with lower circulating levels of atrial and brain natriuretic peptides. These findings indicate that FGF1 expression in the kidney is at least under partial genetic control and that renal expression of several FGF1 partner genes involved in the natriuretic peptide catabolism pathway, renin-angiotensin cascade, and sodium handling network may explain the association between FGF1 and BP.

Signatures of miR-181a on the Renal Transcriptome and Blood Pressure.

MicroRNA-181a binds to the 3' untranslated region of messenger RNA (mRNA) for renin, a rate-limiting enzyme of the renin-angiotensin system. Our objective was to determine whether this molecular interaction translates into a clinically meaningful effect on blood pressure and whether circulating miR-181a is a measurable proxy of blood pressure. In 200 human kidneys from the TRANScriptome of renaL humAn TissuE (TRANSLATE) study, renal miR-181a was the sole negative predictor of renin mRNA and a strong correlate of circulating miR-181a. Elevated miR-181a levels correlated positively with systolic and diastolic blood pressure in TRANSLATE, and this association was independent of circulating renin. The association between serum miR-181a and systolic blood pressure was replicated in 199 subjects from the Genetic Regulation of Arterial Pressure of Humans In the Community (GRAPHIC) study. Renal immunohistochemistry and in situ hybridization showed that colocalization of miR-181a and renin was most prominent in collecting ducts where renin is not released into the systemic circulation. Analysis of 69 human kidneys characterized by RNA sequencing revealed that miR-181a was associated with downregulation of four mitochondrial pathways and upregulation of 41 signaling cascades of adaptive immunity and inflammation. We conclude that renal miR-181a has pleiotropic effects on pathways relevant to blood pressure regulation and that circulating levels of miR-181a are both a measurable proxy of renal miR-181a expression and a novel biochemical correlate of blood pressure.

Male-specific region of the Y chromosome and cardiovascular risk: phylogenetic analysis and gene expression studies.

OBJECTIVE: Haplogroup I of male-specific region of the human Y chromosome is associated with 50% increased risk of coronary artery disease. It is not clear to what extent conventional cardiovascular risk factors and genes of the male-specific region may explain this association. APPROACH AND RESULTS: A total of 1988 biologically unrelated men from 4 white European populations were genotyped using 11 Y chromosome single nucleotide polymorphisms and classified into 13 most common European haplogroups. Approximately 75% to 93% of the haplotypic variation of the Y chromosome in all cohorts was attributable to I, R1a, and R1b1b2 lineages. None of traditional cardiovascular risk factors, including body mass index, blood pressures, lipids, glucose, C-reactive protein, creatinine, and insulin resistance, was associated with haplogroup I of the Y chromosome in the joint inverse variance meta-analysis. Fourteen of 15 ubiquitous single-copy genes of the male-specific region were expressed in human macrophages. When compared with men with other haplogroups, carriers of haplogroup I had ≈ 0.61- and 0.64-fold lower expression of ubiquitously transcribed tetratricopeptide repeat, Y-linked gene (UTY) and protein kinase, Y-linked, pseudogene (PRKY) in macrophages (P=0.0001 and P=0.002, respectively). CONCLUSIONS: Coronary artery disease predisposing haplogroup I of the Y chromosome is associated with downregulation of UTY and PRKY genes in macrophages but not with conventional cardiovascular risk factors.

Genetic imputation of kidney transcriptome, proteome and multi-omics illuminates new blood pressure and hypertension targets.

Genetic mechanisms of blood pressure (BP) regulation remain poorly defined. Using kidney-specific epigenomic annotations and 3D genome information we generated and validated gene expression prediction models for the purpose of transcriptome-wide association studies in 700 human kidneys. We identified 889 kidney genes associated with BP of which 399 were prioritised as contributors to BP regulation. Imputation of kidney proteome and microRNAome uncovered 97 renal proteins and 11 miRNAs associated with BP. Integration with plasma proteomics and metabolomics illuminated circulating levels of myo-inositol, 4-guanidinobutanoate and angiotensinogen as downstream effectors of several kidney BP genes (SLC5A11, AGMAT, AGT, respectively). We showed that genetically determined reduction in renal expression may mimic the effects of rare loss-of-function variants on kidney mRNA/protein and lead to an increase in BP (e.g., ENPEP). We demonstrated a strong correlation (r = 0.81) in expression of protein-coding genes between cells harvested from urine and the kidney highlighting a diagnostic potential of urinary cell transcriptomics. We uncovered adenylyl cyclase activators as a repurposing opportunity for hypertension and illustrated examples of BP-elevating effects of anticancer drugs (e.g. tubulin polymerisation inhibitors). Collectively, our studies provide new biological insights into genetic regulation of BP with potential to drive clinical translation in hypertension.

Peritoneal dialysis as a mode of treatment for acute kidney injury in sub-Saharan Africa.

BACKGROUND: Developing sustainable treatment programs for kidney failure in most countries of sub-Saharan Africa continues to remain an imposing challenge. While long-term renal replacement therapies in end-stage renal disease appear beyond national financial capabilities, there exist opportunities for a short-term and affordable treatment of acute kidney injury (AKI). Peritoneal dialysis (PD) is an effective and simpler modality compared to hemodialysis (HD) and can be performed without the need for machinery or electricity, making it an ideal choice in a low-resource setting. METHODS: Since cost of treatment is the major obstacle, the goal is to develop a program that is cost effective. Developing an HD program requires a large capital investment by the hospital, needing water treatment systems and machinery and providing for their ongoing repair and maintenance. Gravity-driven PD is a simple, effective modality and can be performed in low-resource locales. RESULTS: In a pediatric program that we started in the Komfo Anokye Teaching Hospital in Kumasi, Ghana, 28 patients have been treated with PD for AKI so far. Half of them were treated successfully and were discharged having fully recovered kidney function. Seven patients (25%) were determined to have end-stage renal disease, whereas 7 others (25%) died during hospitalization. In these cases, late presentation for dialysis may have contributed to the inability to recover. CONCLUSION: For individuals and governments alike, who are concerned about the cost of providing or paying for dialysis, using PD to treat AKI is an effective and simpler modality compared to HD and can be performed without the need for machinery or electricity, making it an ideal choice in a low-resource setting.

Different mortality predictor pattern in hemodialysis and peritoneal dialysis diabetic patients in 4-year prospective observation.

INTRODUCTION: The aim was to identify factors carrying an ominous prognosis in a cohort of diabetic patients (pts) on a hemodialysis (HD) and peritoneal dialysis (PD) program. MATERIALS AND METHODS: We analyzed survival rates of 61 diabetic dialysis pts (35 HD/26 PD). The participants were matched in baseline characteristics, standard indicators of dialysis care and laboratory parameters. The studied group was prospectively observed up to 4 years. RESULTS: 21 pts (34.4%) survived the whole observation period. The annual mortality rate was 23.2%, with no difference between HD and PD. Irrespective of dialysis modality, the only factor associated with mortality in the Cox proportional hazard model was serum albumin lowering. Referring to dialysis modality, the HD survivors were characterized by lower IL-6 level, higher albumin concentration, and increased serum cholesterol values with higher cholesterol left in multivariate analysis; under PD therapy the only factor significantly associated with mortality was older age. In contrast to HD treatment, elevated cholesterol was a universal finding in PD patients, significantly above levels in HD, with a slight tendency to lower values in PD survivors. CONCLUSIONS: 1. A difference in mortality predictor pattern appeared in diabetic patients treated by PD and HD. 2. In the PD group more advanced age had a decisive negative impact on survival whereas in the HD group the outlook was dependent on factors related to nutrition and inflammation. 3. Elevated cholesterol level was associated with survival benefit in HD patients, being a common abnormality in the PD group, without positive prognostic significance.

Pathway analysis shows association between FGFBP1 and hypertension.

Variants in the gene encoding fibroblast growth factor 1 (FGF1) co-segregate with familial susceptibility to hypertension, and glomerular upregulation of FGF1 associates with hypertension. To investigate whether variants in other members of the FGF signaling pathway may also associate with hypertension, we genotyped 629 subjects from 207 Polish families with hypertension for 79 single nucleotide polymorphisms in eight genes of this network. Family-based analysis showed that parents transmitted the major allele of the rs16892645 polymorphism in the gene encoding FGF binding protein 1 (FGFBP1) to hypertensive offspring more frequently than expected by chance (P=0.005). An independent cohort of 807 unrelated Polish subjects validated this association. Furthermore, compared with normotensive subjects, hypertensive subjects had approximately 1.5- and 1.4-fold higher expression of renal FGFBP1 mRNA and protein (P=0.04 and P=0.001), respectively. By immunohistochemistry, hypertension-related upregulation of FGFBP1 was most apparent in the glomerulus and juxtaglomerular space. Taken together, these data suggest that FGFBP1 associates with hypertension and that systematic analysis of signaling pathways can identify previously undescribed genetic associations.

[Carbohydrate sweeteners and obesity]. / Weglowodanowe substancje slodzace a otylosc.

The U.S. prevalence of obesity increases since the mid-70s of the 20th century. Around that time high-fructose corn syrup (HFCS)--mixture of fructose and glucose was introduced as a sweetener replacing sucrose in the food production. HFCS containing 55% fructose and 42-45% glucose (HFCS55) has dominated the American soft drink industry and HFCS has recently become commonly used in Poland. The coincidence of HFCS introduction and obesity epidemic raised widely publicized suspicions of a causal relationship between the two. As a possible mechanism, a higher content of fructose in the HFCS55, as compared with sucrose was suggested -fructose is known to increase serum uric acid level, induce hepatic lipogenesis and not stimulate postprandial hyperinsulinemia, a main activator of leptin release. Few comparative studies of HFCS and sucrose have largely failed to reveal any different impacts on the metabolic parameters, yet they were mainly short-term. It has been recently shown that obesity is linked with changes in the intenstinal flora. Among the causes of allegedly different effects of sucrose and HFCS on metabolism, their influence on the gut microbiome has not been examined. Some bacterial types do not hydrolyze sucrose which may determine different compositions of gut flora with the use of both sweeteners. Studies involving quantitative analysis of bacterial DNA in the stool, both in animals and in humans, shall shed light on the issue that has recently so much absorbed the U.S. public opinion.

Uncovering genetic mechanisms of hypertension through multi-omic analysis of the kidney.

The kidney is an organ of key relevance to blood pressure (BP) regulation, hypertension and antihypertensive treatment. However, genetically mediated renal mechanisms underlying susceptibility to hypertension remain poorly understood. We integrated genotype, gene expression, alternative splicing and DNA methylation profiles of up to 430 human kidneys to characterize the effects of BP index variants from genome-wide association studies (GWASs) on renal transcriptome and epigenome. We uncovered kidney targets for 479 (58.3%) BP-GWAS variants and paired 49 BP-GWAS kidney genes with 210 licensed drugs. Our colocalization and Mendelian randomization analyses identified 179 unique kidney genes with evidence of putatively causal effects on BP. Through Mendelian randomization, we also uncovered effects of BP on renal outcomes commonly affecting patients with hypertension. Collectively, our studies identified genetic variants, kidney genes, molecular mechanisms and biological pathways of key relevance to the genetic regulation of BP and inherited susceptibility to hypertension.

A super-agonist of growth hormone-releasing hormone causes rapid improvement of nutritional status in patients with chronic kidney disease.

Chronic kidney disease is frequently associated with protein-energy wasting related to chronic inflammation and a resistance to anabolic hormones such as insulin and growth hormone (GH). In this study, we determined whether a new GH-releasing hormone super-agonist (AKL-0707) improved the anabolism and nutritional status of nondialyzed patients with stage 4-5 chronic kidney disease randomized to twice daily injections of the super-agonist or placebo. After 28 days, this treatment significantly increased 24-h GH secretion by almost 400%, without altering the frequency or rhythmicity of secretory bursts or fractional pulsatile GH release, and doubled the serum insulin-like growth factor-1 level. There was a significant change in the Subjective Global Assessment from 'mildly to moderately malnourished' to 'well-nourished' in 6 of 9 patients receiving AKL-0707 but in none of 10 placebo-treated patients. By dual-energy X-ray absorptiometry, both the mean fat-free mass and the body mineral content increased, but fat mass decreased, all significantly. In the AKL-0707-treated group, both serum urea and normalized protein equivalent of nitrogen appearance significantly decreased with no change in dietary protein intake, indicating a protein anabolic effect of treatment. Thus, our study shows that stimulation of endogenous GH secretion by AKL-0707 overcomes uremic catabolism of patients with advanced chronic kidney disease.

A common variant in low-density lipoprotein receptor-related protein 6 gene (LRP6) is associated with LDL-cholesterol.

OBJECTIVE: A rare mutation in low-density lipoprotein receptor-related protein 6 gene (LRP6) was identified as the primary molecular defect underlying monogenic form of coronary artery disease. We hypothesized that common variants in LRP6 could predispose subjects to elevated LDL-cholesterol (LDL-C). METHODS AND RESULTS: Twelve common (minor allele frequency > or =0.1) single nucleotide polymorphisms in LRP6 were genotyped in 703 individuals from 213 Polish pedigrees (Silesian Cardiovascular Study families). The family-based analysis revealed that the minor allele of rs10845493 clustered with elevated LDL-C in offspring more frequently than expected by chance (P=0.0053). The quantitative analysis restricted to subjects free of lipid-lowering treatment confirmed the association between rs10845493 and age-, sex-, and BMI-adjusted circulating levels of LDL-C in families as well as 2 additional populations - 218 unrelated subjects from Silesian Cardiovascular Study replication panel and 1138 individuals from Young Men Cardiovascular Association cohort (P=0.0268, P=0.0476, and P=0.0472, respectively). In the inverse variance weighted meta-analysis of the 3 populations each extra minor allele copy of rs10845493 was associated with 0.14 mmol/L increase in age-, sex-, and BMI-adjusted LDL-C (SE=0.05, P=0.0038). CONCLUSIONS: Common polymorphism in the gene underlying monogenic form of coronary artery disease impacts on risk of LDL-C elevation.

Fibroblast growth factor 1 gene and hypertension: from the quantitative trait locus to positional analysis.

BACKGROUND: The distal portion of the long arm of chromosome 5 is linked to hypertension and contains functional candidate blood pressure-regulating genes. METHODS AND RESULTS: Tightening the grid of microsatellite markers under this quantitative trait locus in the Silesian Hypertension Study (629 individuals from 207 Polish hypertensive families) provided enhanced support for linkage of this region to blood pressure (maximal Z=3.51, P=0.0002). The fine mapping, comparative genomics, and functional prioritization identified fibroblast growth factor 1 gene (FGF1) as the positional candidate. Linkage disequilibrium mapping based on 51 single nucleotide polymorphisms spanning the locus showed no overlap between 3 independent haploblocks of FGF1 and the adjacent extragenic chromosomal regions. Single and multilocus family-based analysis revealed that genetic variation within FGF1 haploblock 1 was associated with hypertension and identified a common intronic single nucleotide polymorphism, rs152524, as the major driver of this association (P=0.0026). Real-time quantitative polymerase chain reaction and Western blotting analysis of renal tissue obtained from subjects undergoing unilateral nephrectomy showed an increase in both mRNA and protein FGF1 expression in hypertensive patients compared with normotensive controls. Renal immunohistochemistry revealed that FGF1 was expressed exclusively within the glomerular endothelial and mesangial cells. CONCLUSIONS: Our data demonstrate that genetic variation within FGF1 cosegregates with elevated blood pressure in hypertensive families and that this association is likely to be mediated by upregulation of renal FGF1 expression. The results of our study will need to be replicated in other cohorts.

Associations between calcineurin inhibitors and arterial compliance in kidney transplant recipients.

INTRODUCTION: Several studies have suggested an effect of calcineurin inhibitors on arterial compliance in kidney transplant recipients. We aimed to investigate whether the type of calcineurin inhibitor influences large and small artery compliance in these patients independently of other determinants. METHODS: Patients (104 men, 56 women; 124 treated with cyclosporine, 32 with tacrolimus), aged 44.5 +/- 11.0 years (20-69), with kidney graft functioning for 3.7 +/- 2.5 years (0.25-14.2), were studied. Arterial compliance was assessed with the HDI/Pulse Wave CR-2000 System, which estimates large (C1) and small artery (C2) elasticity indices. Blood cell count, serum lipid profile, calcium x phosphate product, concentrations of CRP, total protein and albumin, plasma fibrinogen and glomerular filtration rate were estimated. Multiple linear regression analysis was employed to check for associations between C1, C2 and patients' demographic, clinical and laboratory profiles, including type of calcineurin inhibitor used. RESULTS: Both C1 and C2 correlated positively with body surface area and negatively with age and mean blood pressure. Furthermore, C1 was associated negatively with pulse rate (beta=-0.37; p<0.00001), while C2 was related positively to the interaction term of the current use of tacrolimus x its duration (beta=0.19; p<0.005) and negatively to the simultaneous use of cyclosporine and beta-blocker (beta=-0.18; p<0.003), as well as tacrolimus and low-dose aspirin (beta=-0.24; p<0.0002). CONCLUSIONS: Calcineurin inhibitors differentially influence small artery compliance in kidney transplant recipients. Use of tacrolimus appears to improve small artery compliance proportionally to the duration of treatment, but combinations of tacrolimus and low-dose aspirin, as well as cyclosporine and beta-blocker seem to exert a negative influence.

[The influence of demographic and clinical parameters on arterial elasticity indices in families with hypertension and coronary artery disease]. / Ocena wplywu czynników demograficznych i klinicznych na wskazniki elastycznosci naczyn tetniczych w rodzinach chorych na nadcisnienie tetnicze i chorobe niedokrwienna serca.

The aim of this study was to assess associations between clinical factors and large (C1) and small (C2) artery elasticity indices. The study was performed in a group consisting of 162 persons: 81 men and 81 women (mean age--43.7 +/- 16.1 years), representing 45 families (88 parents--50 suffering from hypertension, 50 with ischaemic heart disease, 9 type 2 diabetic patients and 74 offsprings--5 with hypertension, 1 with ischaemic heart disease). Mean age in the group of parents was 56.4 +/- 8.3 years, in the group of children--28.7 +/- 8.3 years. Arterial elasticity was assessed using HDI Pulsewave TM CR-2000 machine. Subjects with hypertension had lower C1 than those with normotension (12.2 +/- 4.1 vs 15.0 +/- 3.7, p < 0.00002) and diabetic subjects exhibited lower C1 than non-diabetic controls (11.4 +/- 2.8 vs 14.3 +/- 4, p < 0.04). C2 value was significantly lower in subjects with hypertension (4.1 +/- 2.3 vs 6.7 +/- 2.9, p < 8 x 10(-2)) than in normotensives and patients with coronary artery disease had lower C2 than subjects without heart disease (4.2 +/- 2.1 vs 6.6 +/- 3.1, p < 6 x 10(-6)). C1 correlated inversely with systolic (Rs = -0.54, p < 8 x 10(-14)) and diastolic pressure (r = -0.33, p < 0.003), as well as C2. Filial C1 correlated positively with paternal C1 (Rs = 0.3, p < 0.04). Our data indicate that traditional cardiovascular risk factors correlate with marker of arterial elasticity. Correlation between C1 in fathers and sons suggests the familial predisposition in the group of men.

Correlation between serum low-density lipoprotein cholesterol concentration and arterial wall stiffness.

BACKGROUND: Elevated serum low-density lipoprotein cholesterol (LDL-C) concentration is a risk factor for atherosclerosis, which involves remodelling of the arterial walls with their subsequent stiffening. AIM: We sought to evaluate the relationship between serum lipid levels and the elastic properties of the arterial wall. METHODS: The study group comprised 315 men and women aged 55.84 ± 9.44 years. Serum glucose and lipid concentrations were determited. All subjects underwent blood pressure (BP) measurement, transthoracic echocardiography, and assessment of vascular compliance of large (C1) and small arteries (C2) using the HDI/Pulse Wave™ CR-2000 Research CardioVascular Profiling System (Hypertension Diagnostics Inc., Eagan, MN, USA). The subjects were divided into three groups: group I - LDL-C < 2.6 mmol/L, group II - LDL-C ≥ 2.6 mmol/L and < 4.0 mmol/L, and group III - LDL-C ≥ 4.0 mmol/L. RESULTS: There were no intergroup differences with regard to smoking status (p = 0.56), serum glucose concentration (p = 0.13), body mass index (p = 0.96), systolic (p = 0.17) and diastolic BP (p = 0.29), or C1 (p = 0.09). However, C2 was higher in groups I and II than in group III (5.12 ± 2.57 vs. 5.18 ± 2.75 vs. 4.20 ± 1.58 mL/mmHg × 100, respectively, p < 0.01). Multivariate regression analysis negated the independent associations between C1 and serum lipid levels. In contrast, C2 was independently inversely associated with serum LDL-C concentration (r = -0.15, p < 0.01). CONCLUSIONS: Higher serum LDL-C concentration seems to contribute independently to stiffening of small arterial vasculature in otherwise healthy adults. Screening for dyslipidaemia in the general population and its prompt treatment are highly recom-mended.

Molecular insights into genome-wide association studies of chronic kidney disease-defining traits.

Genome-wide association studies (GWAS) have identified >100 loci of chronic kidney disease-defining traits (CKD-dt). Molecular mechanisms underlying these associations remain elusive. Using 280 kidney transcriptomes and 9958 gene expression profiles from 44 non-renal tissues we uncover gene expression partners (eGenes) for 88.9% of CKD-dt GWAS loci. Through epigenomic chromatin segmentation analysis and variant effect prediction we annotate functional consequences to 74% of these loci. Our colocalisation analysis and Mendelian randomisation in >130,000 subjects demonstrate causal effects of three eGenes (NAT8B, CASP9 and MUC1) on estimated glomerular filtration rate. We identify a common alternative splice variant in MUC1 (a gene responsible for rare Mendelian form of kidney disease) and observe increased renal expression of a specific MUC1 mRNA isoform as a plausible molecular mechanism of the GWAS association signal. These data highlight the variants and genes underpinning the associations uncovered in GWAS of CKD-dt.

Association of the human Y chromosome with cholesterol levels in the general population.

OBJECTIVE: Males are at higher risk of cardiovascular diseases than females. The aim of the study was to test whether the potential of the Y chromosome to affect cardiovascular risk could be attributed to its influence on lipids. METHODS AND RESULTS: 1288 Polish men (1157 subjects from young healthy cohort and 131 individuals from middle-aged hypertensive population) were phenotyped for determinants of cardiovascular risk including BMI, blood pressures, lipids, and testosterone. Each subject was genotyped for the HindIII(+/-) polymorphism within the nonrecombining region of the Y chromosome. Men with the HindIII(-) variant exhibited significantly higher total cholesterol (TC) and low-density lipoprotein cholesterol (LDL) levels than subjects with the HindIII(+) genotype in both populations. The differences between the genotypes were 0.15 mmol/L (P=0.0107) and 0.45 mmol/L (P=0.0377) in TC and 0.15 mmol/L (P=0.0059) and 0.41 mmol/L (P=0.0432) in LDL among young apparently healthy men and middle-aged hypertensive men, respectively. The HindIII(+) was associated with a significant increase in blood pressure of the middle-aged men. Testosterone serum concentrations correlated positively with HDL-cholesterol levels, and this association was independent of the Y chromosome. CONCLUSIONS: The results indicate that a locus/loci on the Y chromosome may influence LDL levels, independent of testosterone levels.