We compared a standard antihypertensive losartan treatment with a pharmacogenomics-guided rostafuroxin treatment in never-treated Caucasian and Chinese patients with primary hypertension. ...Rostafuroxin is a digitoxigenin derivative that selectively disrupts the binding to the cSrc-SH2 domain of mutant α-adducin and of the ouabain-activated Na-K pump at 10
M. Of 902 patients screened, 172 were enrolled in Italy and 107 in Taiwan. After stratification for country and genetic background, patients were randomized to rostafuroxin or losartan, being the difference in the fall in office systolic blood pressure (OSBP) after 2-month treatment the primary endpoint. Three pharmacogenomic profiles (P) were examined, considering: P1, adding to the gene variants included in the subsequent P2, the variants detected by post-hoc analysis of a previous trial; P2, variants of genes encoding enzymes for endogenous ouabain (EO) synthesis (LSS and HSD3B1), EO transport (MDR1/ABCB1), adducin (ADD1 and ADD3); P3, variants of the LSS gene only. In Caucasians, the group differences (rostafuroxin 50 μg minus losartan 50 mg in OSBP mmHg) were significant both in P2 adjusted for genetic heterogeneity (P2a) and P3 LSS rs2254524 AA 9.8 (0.6-19.0), P = 0.038 and 13.4 (25.4-2.5), P = 0.031, respectively. In human H295R cells transfected with LSS A and LSS C variants, the EO production was greater in the former (P = 0.038); this difference was abolished by rostafuroxin at 10
M. Chinese patients had a similar drop in OSBP to Caucasians with losartan but no change in OSBP with rostafuroxin. These results show that genetics may guide drug treatment for primary hypertension in Caucasians.
BackgroundThere exists a wide interindividual variability in blood pressure (BP) response to β1‐blockers. To identify the genetic determinants of this variability, we performed a pharmacogenomic ...genome‐wide meta‐analysis of genetic variants influencing β1‐blocker BP response.Methods and ResultsGenome‐wide association analysis for systolic BP and diastolic BP response to β1‐blockers from 5 randomized clinical trials consisting of 1254 patients with hypertension of European ancestry were combined in meta‐analysis and single nucleotide polymorphisms (SNPs) with P<10−4 were tested for replication in 2 independent randomized clinical trials of β1‐blocker–treated patients of European ancestry (n=1552). Regions harboring the replicated SNPs were validated in a β1‐blocker–treated black cohort from 2 randomized clinical trials (n=315). A missense SNP rs28404156 in BST1 was associated with systolic BP response to β1‐blockers in the discovery meta‐analysis (P=9.33×10−5, β=−3.21 mm Hg) and replicated at Bonferroni significance (P=1.85×10−4, β=−4.86 mm Hg) in the replication meta‐analysis with combined meta‐analysis approaching genome‐wide significance (P=2.18×10−7). This SNP in BST1 is in linkage disequilibrium with several SNPs with putative regulatory functions in nearby genes, including CD38, FBXL5, and FGFBP1, all of which have been implicated in BP regulation. SNPs in this genetic region were also associated with BP response in the black cohort.ConclusionsData from randomized clinical trials of 8 European ancestry and 2 black cohorts support the assumption that BST1 containing locus on chromosome 4 is associated with β1‐blocker BP response. Given the previous associations of this region with BP, this is a strong candidate region for future functional studies and potential use in precision medicine approaches for BP management and risk prediction.
In spite of the common belief of Europe as reasonably homogeneous at genetic level, advances in high-throughput genotyping technology have resolved several gradients which define different ...geographical areas with good precision. When Northern and Southern European groups were considered separately, there were clear genetic distinctions. Intra-country genetic differences were also evident, especially in Finland and, to a lesser extent, within other European populations. Here, we present the first analysis using the 125,799 genome-wide Single Nucleotide Polymorphisms (SNPs) data of 1,014 Italians with wide geographical coverage. We showed by using Principal Component analysis and model-based individual ancestry analysis, that the current population of Sardinia can be clearly differentiated genetically from mainland Italy and Sicily, and that a certain degree of genetic differentiation is detectable within the current Italian peninsula population. Pair-wise F(ST) statistics Northern and Southern Italy amounts approximately to 0.001 between, and around 0.002 between Northern Italy and Utah residents with Northern and Western European ancestry (CEU). The Italian population also revealed a fine genetic substructure underscoring by the genomic inflation (Sardinia vs. Northern Italy = 3.040 and Northern Italy vs. CEU = 1.427), warning against confounding effects of hidden relatedness and population substructure in association studies.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The peculiar position of Sardinia in the Mediterranean sea has rendered its population an interesting biogeographical isolate. The aim of this study was to investigate the genetic population ...structure, as well as to estimate Runs of Homozygosity and regions under positive selection, using about 1.2 million single nucleotide polymorphisms genotyped in 1077 Sardinian individuals. Using four different methods--fixation index, inflation factor, principal component analysis and ancestry estimation--we were able to highlight, as expected for a genetic isolate, the high internal homogeneity of the island. Sardinians showed a higher percentage of genome covered by RoHs>0.5 Mb (F(RoH%0.5)) when compared to peninsular Italians, with the only exception of the area surrounding Alghero. We furthermore identified 9 genomic regions showing signs of positive selection and, we re-captured many previously inferred signals. Other regions harbor novel candidate genes for positive selection, like TMEM252, or regions containing long non coding RNA. With the present study we confirmed the high genetic homogeneity of Sardinia that may be explained by the shared ancestry combined with the action of evolutionary forces.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Genome-wide association studies have identified a high number of genetic loci associated with hypertension suggesting the presence of an underlying polygenic architecture. In this study, we aimed to ...dissect the polygenic component of primary hypertension searching also for pathway-specific components.
The polygenic risk score (PRS) models, based on the UK biobank genetic signals for hypertension status, were obtained on a target Italian case/control cohort including 561 cases and 731 hyper-normal controls from HYPERGENES, and were then applied to an independent validation cohort composed by multi-countries European-based samples including 1,284 cases and 960 hyper-normal controls.
The resulting genome-wide PRS was capable of stratifying the individuals for hypertension risk by comparing between individuals in the last PRS decile and the median decile: we observed an odds ratio (OR) of 3.62, CI = 2.01, 6.32 (
= 9.01E-07) and 3.22, 95% CI = 2.06, 5.10 (
= 6.47E-08) in the target and validation cohorts, respectively. The relatively high case/control ORs across PRS quantiles corroborates the presence of strong polygenic components which could be driven by an enrichment of risk alleles within the cases but also by potential enrichment of protective alleles in the old normotensive controls. Moreover, novel pathway-specific PRS revealed an enrichment of the polygenic signal attributable to specific biological pathways. Among those the most significantly associated with hypertension status was the calcium signaling pathway together with other mainly related such as the phosphatidylinositol/inositol phosphate pathways.
The development of pathway-specific PRS could prioritize biological mechanisms, according to their contribution to the genetic susceptibility, whose regulations might be a potential pharmacological preventive target.
Identification of susceptibility genes for essential hypertension in humans has been a challenge due to its multifactorial pathogenesis complicated by gene-gene and gene-environment interactions, ...developmental programing and sex specific differences. These concurrent features make identification of causal hypertension susceptibility genes with a single approach difficult, thus requiring multiple lines of evidence involving genetic, biochemical and biological experimentation to establish causal functional mutations. Here we report experimental evidence encompassing genetic, biochemical and in vivo modeling that altogether support ATP1A1 as a hypertension susceptibility gene in males in Sardinia, Italy. ATP1A1 encodes the α1Na,K-ATPase isoform, the sole sodium pump in vascular endothelial and renal tubular epithelial cells. DNA-sequencing detected a 12-nucleotide long thymidine (12T) insertion(ins)/deletion(del) polymorphism within a poly-T sequence (38T vs 26T) in the ATP1A1 5'-regulatory region associated with hypertension in a male Sardinian population. The 12T-insertion allele confers decreased susceptibility to hypertension (P = 0.035; OR = 0.50 0.28-0.93) accounting for 12.1 mmHg decrease in systolic BP (P = 0.02) and 6.6 mmHg in diastolic BP (P = 0.046). The ATP1A1 promoter containing the 12T-insertion exhibited decreased transcriptional activity in in vitro reporter-assay systems, indicating decreased α1Na,K-ATPase expression with the 12T-insertion, compared with the 12T-deletion ATP1A1 promoter. To test the effects of decreased α1Na,K-ATPase expression on blood pressure, we measured blood pressure by radiotelemetry in three month-old, highly inbred heterozygous knockout ATP1A1+/- male mice with resultant 58% reduction in ATP1A1 protein levels. Male ATP1A1+/- mice showed significantly lower blood pressure (P < 0.03) than age-matched male wild-type littermate controls. Concordantly, lower ATP1A1 expression is expected to lower Na-reabsorption in the kidney thereby decreasing sodium-associated risk for hypertension and sodium-induced endothelial stiffness and dysfunction. Altogether, data support ATP1A1 as a hypertension susceptibility gene in a male Sardinian population, and mandate further investigation of its involvement in hypertension in the general population.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Twenty years of genetic studies have not contributed to improvement in the clinical management of primary arterial hypertension. Genetic heterogeneity, epistatic-environmental-biological ...interactions, and the pathophysiological complexity of hypertension have hampered the clinical application of genetic findings. In the companion article, we furnished data from rodents and human cells demonstrating two hypertension-triggering mechanisms--variants of adducin and elevated concentrations of endogenous ouabain (within a particular range)--and their selective inhibition by the drug rostafuroxin. Here, we have investigated the relationship between variants of genes encoding enzymes for ouabain synthesis LSS (lanosterol synthase) and HSD3B1 (hydroxy-δ-5-steroid dehydrogenase, 3β- and steroid δ-isomerase 1), ouabain transport {MDR1/ABCB1 ATP-binding cassette, sub-family B (MDR/TAP), member 1}, and adducin activity ADD1 (adducin 1) and ADD3, and the responses to antihypertensive medications. We determined the presence of these variants in newly recruited, never-treated patients. The genetic profile defined by these variants predicted the antihypertensive effect of rostafuroxin (a mean placebo-corrected systolic blood pressure fall of 14 millimeters of mercury) but not that of losartan or hydrochlorothiazide. The magnitude of the rostafuroxin antihypertensive effect was twice that of antihypertensive drugs recently tested in phase 2 clinical trials. One-quarter of patients with primary hypertension display these variants of adducin or concentrations of endogenous ouabain and would be expected to respond to therapy with rostafuroxin. Because the mechanisms that are inhibited by rostafuroxin also underlie hypertension-related organ damage, this drug may also reduce the cardiovascular risk in these patients beyond that expected by the reduction in systolic blood pressure alone.
Coronary artery disease, heart failure, fatal arrhythmias, stroke, and renal disease are the most common causes of mortality for humans, and essential hypertension remains a major risk factor. ...Elucidation of susceptibility loci for essential hypertension has been difficult because of its complex, multifactorial nature involving genetic, environmental, and sex- and age-dependent nature. We investigated whether the 11p15.5 region syntenic to rat chromosome 1 region containing multiple blood pressure quantitative trait loci (QTL) detected in Dahl rat intercrosses harbors polymorphisms that contribute to susceptibility/resistance to essential hypertension in a Sardinian population. Initial testing performed using microsatellite markers spanning 18 Mb of 11p15.5 detected a strong association between D11S1318 (at 2.1 Mb, P = 0.004) and D11S1346 (at 10.6 Mb, P = 0.00000004), suggesting that loci in close proximity to these markers may contribute to susceptibility in our Sardinian cohort. NLR family, pyrin domain containing 6/angiotensin-vasopressin receptor (NLRP6/AVR), and adrenomedullin (ADM) are in close proximity to D11S1318 and D11S1346, respectively; thus we tested single nucleotide polymorphisms (SNPs) within NLRP6/AVR and ADM for their association with hypertension in our Sardinian cohort. Upon sex stratification, we detected one NLRP6/AVR SNP associated with decreased susceptibility to hypertension in males (rs7948797G, P = 0.029; OR = 0.73 0.57-0.94). For ADM, sex-specific analysis showed a significant association between rs4444073C, with increased susceptibility to essential hypertension only in the male population (P = 0.006; OR = 1.44 1.13-1.84). Our results revealed an association between NLRP6/AVR and ADM loci with male essential hypertension, suggesting the existence of sex-specific NLRP6/AVR and ADM variants affecting male susceptibility to essential hypertension.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Autosomal recessive hypercholesterolaemia (ARH) is caused by mutations in a putative adaptor protein called ARH. This recessive disorder, characterised by severe hypercholesterolaemia, xanthomatosis, ...and premature coronary artery disease, is rare except on the island of Sardinia, Italy. Our aim was to ascertain why ARH is more common on Sardinia than elsewhere.
We obtained detailed medical histories, did physical examinations, measured concentrations of lipoproteins, and harvested genomic DNA from 28 Sardinians with ARH from 17 unrelated families. We sequenced the coding regions and consensus splice sites of ARH in probands from these families, and from 40 individuals of non-Sardinian origin who had an autosomal recessive form of hypercholesterolaemia of unknown cause.
Two ARH mutations, a frameshift mutation (c432insA) in exon 4 (ARH1) and a nonsense mutation (c65G-A) in exon 1 (ARH2), were present in all of the 17 unrelated families with ARH. Three of the ARH alleles contained both mutations, as a result of an ancient recombination between ARH1 and ARH2. No regional clustering of the three mutant alleles within Sardinia was apparent. Furthermore, four Italians from the mainland with autosomal recessive hypercholesterolaemia were homozygous for ARH1.
The small number, high frequency, and dispersed distribution of ARH mutations on Sardinia are consistent with these mutations being ancient and maintained in the Sardinian population because of geographic isolation.
Many patients with hypertension will require multiple antihypertensive drugs to achieve blood pressure (BP) control. This double-blind study evaluated the efficacy and safety of aliskiren/amlodipine ...single-pill combinations (SPCs) in patients with mild-to-moderate hypertension who were non-responsive to aliskiren monotherapy. After a 4-week run-in with aliskiren 300 mg, patients with mean sitting diastolic BP (msDBP) ≥ 90 and < 110 mmHg were randomized to oncedaily aliskiren/ amlodipine 300/10 mg or 300/5 mg, or aliskiren 300 mg for 8 weeks. Aliskiren/amlodipine SPCs provided significantly greater mean reductions in mean sitting systolic BP/msDBP (300/10 mg, 18.0/13.1 mmHg; 300/5 mg, 14.4/10.5 mmHg) than aliskiren 300 mg (6.4/5.8 mmHg) at week 8 endpoint. This represents additional mean reductions of 11.6/7.2 mmHg (300/10 mg) and 8.0/4.7 mmHg (300/5 mg) over aliskiren alone (both p < 0.0001). Significantly more patients achieved BP control ( < 140/90 mmHg) with aliskiren/amlodipine 300/10 mg (65.5%) and 300/5 mg (56.6%) than with aliskiren (31.5% both p < 0.0001). Aliskiren, alone and in combination with amlodipine, was well tolerated, with a slightly higher incidence of adverse events with SPCs (29.0-30.1%) than with monotherapy (22.7%). In conclusion, aliskiren/amlodipine SPCs offer an effective next step for patients who have an inadequate BP response to aliskiren alone.
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