A single nucleotide polymorphism in the promoter region of the osteoprotegerin gene is related to intima‐media thickness of the carotid artery in hypertensive patients. The Swedish irbesartan left ventricular hypertrophy investigation vs atenolol (SILVHIA)

Association of a single nucleotide polymorphism of RANK gene with blood pressure in Spanish women

In addition to governing key functions in bone metabolism and the immune system, the RANK/RANKL/OPG system plays a role in the vascular system, particularly in vascular calcification and atherosclerosis.Given that these 2 phenotypes are considered a major cause of high blood pressure (BP), in this study we analyzed the association of SNPs in RANK and OPG genes with blood pressure. An observational study was conducted of 2 SNPs in the RANK gene (rs884205 and rs78326403) and 1 in the OPG gene (rs4876869) with systolic (SBP) and diastolic blood pressure (DBP) in a cohort of 695 women.Data analysis revealed a statistically significant association between the SNP rs884205 and BP pressure (SBP and DBP). Analyzing this relationship by the dominant inheritance model for this SNP (allele risk: A), women of the AA/AC genotype showed higher BP than women of the CC genotype, both for SBP (P = .001) and for DBP (P = .003), and these associations both surpassed the Bonferroni threshold for multiple comparisons. Multivariate regression analysis including known predictors of BP as independent variables was performed to evaluate the strength of this association, which in the case of the SNP rs884205 of the RANK gene remained statistically significant after adjustment for both SBP (P = .0006) and DBP (P = .005), demonstrating the key role of this SNP in BP.We report a robust association between the SNP rs884205 in RANK gene and BP in women, and this SNP is validated as a candidate in cardiovascular risk studies.

Bone Mineral Density Is Positively Related to Carotid Intima-Media Thickness: Findings From a Population-Based Study in Adolescents and Premenopausal Women

Osteoporosis and cardiovascular disease (CVD) are both common causes of morbidity and mortality. Previous studies, mainly of people older than 60 years, suggest a relationship between these conditions. Our aim was to determine the association between bone characteristics and CVD markers in younger and middle-aged individuals. Women (n = 3366) and their adolescent offspring (n = 4368) from the UK population-based cohort study, Avon Longitudinal Study of Parents and Children (ALSPAC), were investigated. We measured total body (TB) and hip bone mineral density (BMD), TB bone area (BA) and bone mineral content (BMC) by dual-energy X-ray absorptiometry (DXA), and carotid intima-media thickness (cIMT) by high-resolution ultrasound. Arterial distensibility was calculated as the difference between systolic and diastolic arterial diameters. Linear regression determined associations between bone exposures and cIMT (in adolescents) and both cIMT and arterial distensibility (in women), generating partial correlation coefficients. Mean (SD) age of women was 48 (4.2) years, body mass index (BMI) was 26.2 (5.0) kg/m² , and 71% were premenopausal. In confounder-adjusted analyses (age, height, lean mass, fat mass, menopause, smoking, estrogen replacement, calcium/vitamin D supplementation, and education) TB and hip BMD were both positively associated with cIMT (0.071 [0.030, 0.112], p = 0.001; 0.063 [0.025, 0.101], p = 0.001, respectively). Femoral neck BMD and TB BMD, BMC, and BA were positively associated with arterial distensibility. Mean (SD) age of adolescents was 17 (0.4) years, BMI was 23 (4.1) kg/m² , and 44.5% were male. Total hip and TB measurements were positively associated with cIMT, with similar magnitudes of association to those found in their mothers. In contrast to most published findings, we identified weak positive associations between BMD and cIMT in predominantly premenopausal women and their adolescent offspring. We found greater femoral neck BMD and TB DXA measurements to be associated with reduced arterial stiffness. Rather than a relationship with preclinical atherosclerosis, in these relatively young populations, we speculate our associations between BMD, cIMT, and arterial distensibility may reflect a shared relationship between bone and vascular growth and development. © 2016 American Society for Bone and Mineral Research.

Association of gene polymorphisms in RANKL/RANK/OPG system with hypertension and blood pressure in Chinese women

Recent studies have revealed that the receptor activator of nuclear factor-kappa B ligand/RANK/osteoprotegerin (RANKL/RANK/OPG) system has an important role in vascular calcification, which is contributory to various cardiovascular diseases and intimately linked to the regulation of blood pressure. Therefore, we performed a case-control study to investigate the associations of 21 single-nucleotide polymorphisms (SNPs) in the TNFSF11, TNFRSF11A and TNFRSF11B genes in the RANKL/RANK/OPG system with hypertension and blood pressure in post-menopausal Chinese women. In this study, 503 hypertensive patients and 509 normal controls were recruited. Genotyping was performed using the high-throughput Sequenom genotyping platform. The results showed that two SNPs (rs6567270 and rs4603673) in the TNFRSF11A were associated with hypertension (P=0.010 and P=0.013, respectively) and systolic blood pressure (P=0.024 and P=0.023, respectively). One SNP (rs9646629) in the TNFRSF11A showed significant association with diastolic blood pressure (P=0.031). The results of this study suggest that TNFRSF11A but not TNFSF11 and TNFRSF11B genetic variation is associated with hypertension and blood pressure in Chinese women. The findings provide additional support for the genetic role of RANKL/RANK/OPG system in hypertension and blood pressure regulation.

Osteoprotegerin in Cardiometabolic Disorders

Osteoprotegerin (OPG), a glycoprotein traditionally implicated in bone remodelling, has been recently related to cardiovascular disease (CVD). Human studies show a positive relationship between circulating OPG, vascular damage, and CVD, and as such OPG has emerged as a potential biomarker for CVD. This review focuses on the relationship between circulating OPG and different endocrine cardiometabolic alterations such as type 1 and 2 diabetes. The association of OPG with diabetic complications (neuropathy, nephropathy, or retinopathy) as well as with atherosclerosis, coronary artery calcification, morbidity, and mortality is pointed out. Moreover, OPG modulation by different treatments is also established. Besides, other associated diseases such as obesity, hypertension, and metabolic syndrome, which are known cardiovascular risk factors, are also considered.

Role of osteoprotegerin and its gene polymorphisms in the occurrence of left ventricular hypertrophy in essential hypertensive patients

The aim of the study was to investigate the role of osteoprotegerin (OPG) in left ventricular hypertrophy (LVH) development in patients with essential hypertension (EH). A total of 1092 patients diagnosed with EH were recruited. The LVHs were determined and OPG gene polymorphisms were genotyped. Patients with LVH had a significantly higher mean serum OPG level than those without LVH. The 1181CC genotype carriers had significantly lower risk for LVH compared with GC and GG genotype carriers. The serum OPG level and OPG 1181 G>C polymorphism were found to be independent risk factors for the occurrence of LVH in hypertensive patients. In vitro study shows that OPG overexpression upregulates cell surface size, protein synthesis per cell, and hypertrophy- and fibrosis-related proteins in both cardiomyocytes and cardiac fibroblasts, whereas OPG inhibition can abolish the above-mentioned changes. Consistent with the in vitro data, our in vivo study revealed that the OPG administration induced the LVH in hypertensive rats. This study is the first to report the close association between OPG and LVH development in EH patients and the regulatory effect of OPG on cardiomyocytes and cardiac fibroblasts.

The role of osteoprotegerin in cardiovascular disease

Osteoprotegerin (OPG) is a 401 amino acid N-glycosylated protein, which is highly expressed in a large number of tissues. OPG mainly binds to two ligands, i.e. RANKL (receptor activator of nuclear factor κB ligand) and TRAIL (tumor necrosis factor- related apoptosis-inducing ligand). Upon binding to the former ligand, OPG inhibits the activation of osteoclasts and promotes apoptosis of osteoclasts, whereas the binding of OPG with TRAIL prevents apoptosis of tumor cells. There is now emerging evidence that OPG participates in the pathogenesis of atherosclerosis and cardiovascular diseases by amplifying the adverse effects of inflammation and several traditional risk factors such as hyperlipidemia, endothelial dysfunction, diabetes mellitus, and hypertension. Some epidemiological studies also showed a positive association between OPG levels and cardiovascular morbidity and mortality. The aim of this article is to provide an overview of the main biochemical, physiological, and pathological aspects of OPG biology in cardiovascular disease.

Expression of osteoprotegerin in placenta and its association with preeclampsia

BACKGROUND

Osteoprotegerin (OPG), a key regulatory factor in bone metabolism, was documented also a potential pro-angiogenic factor, which acts an important role in protecting vascular endothelial cells. Since preeclampsia has gradually been employed to be vascular diseases, we speculated that OPG might be associated with preeclampsia. The study was to evaluate the level of OPG protein and mRNA in placenta, and investigate the relationship between OPG and the pathogenesis of preeclampsia.

METHODOLOGY/PRINCIPAL FINDINGS

Placental specimens from 30 term normal pregnancy, 30 severe preeclampsia and 30 mild cases were studied. The expression and levels of OPGs' protein and mRNA were detected by immunohistochemistry, western blot analysis and real-time quantitative PCR analysis respectively. The expression of OPG protein was found in cytoplasm of placenta cytotrophoblasts and syncytiotrophoblasts in three groups. There were no significant differences of OPG protein between the maternal and fetal side in each group. The OPG protein and mRNA levels in severe preeclampsia were significantly higher than those in mild cases and normal pregnancy. However, there were no markedly differences of the OPG protein and mRNA levels between term delivery and preterm delivery in severe cases. In preeclampsia, the OPG protein and mRNA level was positively correlated with systolic blood pressure and 24 h urinary protein respectively.

CONCLUSIONS/SIGNIFICANCE

OPG protein and mRNA level in placentas of preeclampsia were found abnormal compared with normal pregnancy. In preeclampsia, the OPG protein and mRNA levels were closely related with its important clinical parameters. Taken together, OPG might be closely correlated with the pathogenesis of preeclampsia.

A cohort study of the effects of serum osteoprotegerin and osteoprotegerin gene polymorphisms on cardiovascular mortality in elderly women

OBJECTIVE

To investigate the role of serum osteoprotegerin (OPG) and OPG gene polymorphisms in relation to cardiovascular (CV) and all-cause mortality in elderly women.

BACKGROUND

The OPG/RANK/RANKL plays a vital role in bone cell biology. It has also been detected in myocardial tissue and atherosclerotic plaques. In some population studies, OPG and OPG gene polymorphisms have been associated with CV disease risk.

DESIGN, MEASUREMENTS AND RESULTS

In an 8.5-year cohort population study of 1333 postmenopausal women mean age 75.2 ± 2.7 years, serum OPG concentrations above the median were associated with an increased risk of all-cause [odds ratio (OR) 1.39 (1.04-1.85)], and in particular CV mortality [OR 1.83 (1.10-3.05)], before and after adjusting for age, BMI, treated hypertension, diabetes, hypercholesterolemia, previous HRT use, calcium supplementation and smoking. Genotyping the OPG gene did not provide further information on the association between OPG and CV risk or mortality events.

CONCLUSIONS

Raised osteoprotegerin appears to be an independent risk factor for total and CV death and thus has potential as a useful biomarker of risk as well as a potential target for therapeutic intervention.

A single-nucleotide polymorphism in the gene encoding osteoprotegerin is associated with diastolic blood pressure in older men

BACKGROUND

Osteoprotegerin (OPG) has been associated with cardiovascular events but currently the mechanisms underlying this association are unknown. OPG is thought to play a role in controlling artery calcification and small studies have suggested that it may influence artery structure. We examined the association between single nucleotide polymorphisms (SNPs) in the gene encoding OPG (tumor necrosis factor receptor superfamily, member 11b, TNFRSF11B), with blood pressure in a large cohort of elderly men.

METHODS

21 tagging SNPs in the region encoded by TNFRSF11B were examined in 1,071 men recruited in a population-based study of elderly men. Genotyping was carried out using the Illumina Golden Gate assay. SNPs were investigated for their association with resting systolic and diastolic blood pressure after adjusting for other variables using linear regression. The association of SNPs in the region encoded by TNFRSF11B with plasma OPG was assessed in a random subset of 467 men.

RESULTS

One SNP, rs11573901, was significantly associated with diastolic blood pressure, after adjusting for other risk factors and multiple testing (coefficient -4.36, P = 0.001). Men with the TC genotype had lower diastolic blood pressure than those with the common cc variation. this snp was not associated with plasma opg in the 467 men in which this was examined.

CONCLUSIONS

This study suggests that a SNP within the region encoded by TNFRSF11B, which is believed to code for OPG, is associated with blood pressure. The mechanism underlying this observed association is currently unclear.

Serum osteoprotegerin is associated with carotid intima media thickness in women with previous gestational diabetes

Circulating levels of osteoprotegerin (OPG) have been shown to be increased in patients with cardiovascular disorders and diabetes. The aim of this study was to determine serum OPG levels in women with previous gestational diabetes (GDM), and to investigate the relationship between OPG and carotid intima media thickness (IMT) and circulating cardiovascular risk factors. Serum OPG was measured in 46 women with previous GDM and 30 age-matched healthy controls. Carotid IMT was evaluated. Serum lipid, insulin and hsCRP levels, plasma fibrinogen, vWF and PAI-1 levels were measured. Serum OPG levels tended to be increased in women with previous GDM (p=0.058). Carotid IMT was increased in the study group. Women with previous GDM had elevated levels of hsCRP and PAI-1. OPG levels were positively correlated with age, fasting and post-load glucose levels, hsCRP, and carotid IMT. Multiple regression analysis showed that serum OPG was a statistically significant predictor for elevated carotid IMT. Our results revealed that OPG levels tended to be elevated in women with previous GDM. Significant association of OPG with carotid IMT suggested that OPG might play a role in the pathogenesis of endothelial dysfunction in women with previous GDM.

Pathogenesis of calciphylaxis: Hans Selye to nuclear factor kappa-B

The clinical syndrome of calciphylaxis is characterized by arteriolar medial calcification, thrombotic cutaneous ischemia, necrotic skin ulceration, and a high mortality rate. This review integrates calciphylaxis risk factors with the molecular processes governing osseous and extraosseous mineralization. As the pathogenesis of calciphylaxis is better understood, targeted therapies aimed at disease prevention and reversal will follow.

Polymorphisms at the Osteoprotegerin and Interleukin-6 Genes in Relation to First-Ever Stroke

BACKGROUND

Arterial calcification and osteoporosis often coexist, especially in postmenopausal women. Osteoporosis associates with a substantially increased risk of stroke in elderly women, suggesting that impaired estrogen signaling may link stroke and osteoporosis. Osteoprotegerin (OPG, TNFRSF11B) and interleukin-6 (IL-6, IL6) are putative target genes for estrogen signaling and have been implicated in both cardiovascular diseases and osteoporosis. We hypothesized that specific polymorphisms in these genes may be associated with increased risk of ischemic stroke or intracerebral hemorrhage (ICH).

METHODS

We performed a population-based prospective nested case-control study, in which the relationships between polymorphisms (OPG-1181G/C, OPG-950T/C and IL6-174G/C) and ischemic stroke and ICH were examined. Definitive first-ever stroke events (n = 388), i.e. ischemic stroke (n = 320), ICH (n = 61) and unspecified stroke (n = 7) cases, and controls without cardiovascular disease (n = 773), matched for age, sex and geographical region were studied. Univariate and multivariate models using conditional logistic regression, which included traditional risk factors, were used to test for association.

RESULTS

Carriers of the OPG-1181C/C genotype had a significantly (p = 0.018) increased risk of ICH (OR, 2.69; 95% CI, 1.19-6.12) in the univariate analysis. After adjustments (hypertension, diabetes, BMI and triglycerides), this genotype remained significantly (p = 0.005) associated with ICH (OR, 6.04; 95% CI, 1.71-21.29). By contrast, no correlations were found between this genotype and ischemic stroke, nor between the OPG-950T/C or IL6-174G/C polymorphisms and stroke subtypes.

CONCLUSIONS

In this population, the OPG-1181C/C genotype associates with first-ever ICH, implying that alterations in OPG-mediated signaling in the vasculature may be involved in the pathophysiology of this disease.

Heritability of carotid intima-media thickness: a twin study

OBJECTIVE

To estimate the heritability of carotid intima-media thickness (IMT), a surrogate marker for atherosclerosis, independent of traditional coronary risk factors.

METHODS AND RESULTS

We performed a classical twin study of carotid IMT using 98 middle-aged male twin pairs, 58 monozygotic (MZ) and 40 dizygotic (DZ) pairs, from the Vietnam Era Twin Registry. All twins were free of overt cardiovascular disease. Carotid IMT was measured by ultrasound. Bivariate and multivariate analyses were used to determine the association between traditional cardiovascular risk factors and carotid IMT. Intraclass correlation coefficients and genetic modeling techniques were used to determine the relative contributions of genes and environment to the variation in carotid IMT. In our sample, the mean of the maximum carotid IMT was 0.75+/-0.11. Age, systolic blood pressure and HDL were significantly associated with carotid IMT. The intraclass correlation coefficient for carotid IMT was larger in MZ (0.66; 95% confidence interval [CI], 0.62-0.69) than in DZ twins (0.37; 95% CI, 0.29-0.44), and the unadjusted heritability was 0.69 (95% CI, 0.54-0.79). After adjusting for traditional coronary risk factors, the heritability of carotid IMT was slightly reduced but still of considerable magnitude (0.59; 95% CI, 0.39-0.73).

CONCLUSION

Genetic factors have a substantial influence on the variation of carotid IMT. Most of this genetic effect occurs through pathways independent of traditional coronary risk factors.

The osteoprotegerin/RANK/RANKL system: a bone key to vascular disease

Owing to the common coincidence of osteoporosis and vascular disease, pathophysiological links between both disorders have long been sought. The osteoprotegerin (OPG)/receptor activator of NF-kappaB (RANK)/receptor activator of NF-kappaB ligand (RANKL) cytokine network, a key regulatory system in bone homeostasis, has been implicated recently in vascular calcification, changes in matrix composition and diabetic macroangiopathy, aortic aneurysm development, heart failure and, most importantly, advanced atherosclerosis, plaque destabilization and manifestation of cardiovascular diseases. The concept of an active role of RANKL and OPG in vascular pathophysiology is intriguing and is gaining increasing support from both epidemiological and basic research. OPG serum level is considered to be a stable and reliable indicator of the overall activity of the OPG/RANK/RANKL axis and may find application as a biomarker of vascular risk and prognosis. RANKL in turn may be a suitable target for novel therapies. Pharmacological strategies for specific interference with the OPG/RANK/RANKL axis are currently being developed and evaluated in osteoporosis therapy.

The relationship between four single nucleotide polymorphisms in the promoter region of the osteoprotegerin gene and aortic calcification or coronary artery disease in Koreans

OBJECTIVE

Osteoprotegerin (OPG) is a recently identified cytokine that acts as a decoy receptor for the receptor activator of the NF-kappaB ligand (RANKL). OPG has been shown to be an important inhibitor of osteoclastogenesis and arterial calcification in animal models. OPG has been proposed as a link molecule between osteoporosis and arterial calcification, but the relationship between the OPG gene and the cardiovascular system in human populations is unclear. Thus, the aim of this study was to investigate the relationship between OPG gene polymorphisms and aortic calcification or coronary artery disease in Koreans.

DESIGN AND PATIENTS

Genotyping of four polymorphisms, A163G, G209A, T245G and T950C, in the promoter region of the OPG gene was performed in 251 healthy Korean women (mean age 51.3 +/- 6.9 years) and in a second study population consisting of 100 patients who underwent coronary angiography (mean age 57.0 +/- 11.9 years), by allelic discrimination using the 5' nuclease polymerase chain reaction assay. Cardiovascular risk factors and serum OPG levels were measured and aortic calcification in thoracic and abdominal aorta was examined by simple radiological methods.

RESULTS

In the first study population, the prevalence of aortic calcification increased significantly as the subjects grew older. The frequencies of mutant alleles were significantly higher in the subjects with aortic calcification compared with those without aortic calcification in G209A and T950C polymorphisms, although these significances were lost after adjustment for age. No significant relationship was found between OPG gene polymorphisms and serum OPG levels or cardiovascular risk factors. In the second study group, there were no associations between OPG promoter genotypes and aortic calcification, serum OPG levels, or coronary artery disease.

CONCLUSIONS

We observed that the four polymorphisms in the promoter region of the OPG gene were not associated with aortic calcification or coronary artery disease in Koreans. Further studies are needed to clarify this relationship.

Genetic determinants of carotid ultrasound traits

Atherosclerosis is a complex disease with various intermediate phenotypes that are themselves complex and influenced by many factors. Through the use of carotid ultrasound techniques, the intermediate stages of vascular disease can be imaged and studied for association with potential genetic determinants. In this article we review the most recent available data (reports published since 2004) on the genetic determinants of atherosclerosis, as measured by one-, two-, and three-dimensional ultrasonography of the carotid arteries. In general, associations are disparate and modest. For intima-media thickness, promising associations have been found for both TNFRSF1A R92Q and PPARG P12A, but associations also differed in the same individuals depending on the specific ultrasound trait studied (eg, linear intima-media thickness versus total plaque volume in carotid arteries). Some of the challenging issues for future studies include accounting for gene-environment interactions, sex-specific associations, and the distinctiveness of different carotid ultrasound measures.

Genetic variants predisposing to cardiovascular disease

PURPOSE OF REVIEW

The goal of this review is to provide an update on the most recent and relevant findings in the area of genotype-phenotype associations as well as the relationships between genetic factors and cardiovascular disease risk markers and events. In addition, emphasis will be placed on the methodological problems associated with studying the genetics of complex disorders, specifically cardiovascular diseases.

RECENT FINDINGS

Genes associated with cardiovascular disease predisposition have been examined, including traditional cardiovascular disease candidate genes, such as ACE, AGT, eNOS, PON and MTHFR, new loci that have recently been added to the growing list of cardiovascular disease candidate genes (i.e. MEF2A, ALOX5, LTA, APOM, PDE4D), and genes that have been shown to be at the intersection of several age-related disorders through interaction with one another or with environmental factors (i.e. APOA5, APOE, PPARgamma, LPL and LIPC).

SUMMARY

During the last year, tremendous effort has been made in elucidating new genes associated with cardiovascular disease predisposition. For the most part, however, major breakthroughs have not been made, primarily due to the poor replication of results among studies, as a consequence of poor experimental design. Nevertheless, we have increased our understanding of the complexity of cardiovascular disease and the relevance of gene-environment interactions as the ultimate drivers of the individual predisposition to the disease. It is essential, therefore, that present and future genetic studies in this area take into consideration the inclusion of high-quality environmental data in the analytical process to test the clinical usefulness of a genetic marker as a risk predictor.