Vitamin D deficiency is associated with significant coronary stenoses in asymptomatic African American chronic cocaine users

The Interplay of Vitamin D Deficiency and Cellular Senescence in The Pathogenesis of Obesity-Related Co-Morbidities

This scoping review aims to clarify the interplay between obesity, vitamin D deficiency, cellular senescence, and obesity-related metabolic consequences, mainly subclinical atherosclerosis, and non-alcoholic fatty liver disease (NAFLD). Obesity is a significant global health problem that involves cellular, environmental, behavioral, and genetic elements. The fundamental cause of obesity throughout all life stages is an energy imbalance, and its consequences are countless and, foremost, very common. Obesity has been comprehensively studied in the literature given its association with low serum vitamin D, with many proposed mechanisms linking the two conditions. Moreover, markers of exaggerated cellular senescence have been proven to accumulate in obese individuals. Subclinical atherosclerosis initiates an early stage that ends in serious cardiac events, and obesity, low vitamin D, and senescent cells largely contribute to its associated chronic low-grade inflammation. Furthermore, NAFLD signifies the hepatic manifestation of metabolic syndrome, and studies have highlighted the important role of obesity, vitamin D deficiency, and cellular senescence in its development. Therefore, we outlined the most important mechanisms tying these conditions to one another.

Cellular Senescence and Vitamin D Deficiency Play a Role in the Pathogenesis of Obesity-Associated Subclinical Atherosclerosis: Study of the Potential Protective Role of Vitamin D Supplementation

The exact link between obesity, vitamin D deficiency, and their relation to cellular senescence in the pathogenesis of subclinical atherosclerosis is still under debate. Therefore, the current study aims to verify the possible role of vitamin D deficiency and cellular senescence in the pathogenesis of obesity-related subclinical atherosclerosis. Moreover, it aims to investigate the possible protective role of vitamin D supplementation. Fifty-seven male albino rats were enrolled in the study and classified into four groups: negative (10) and positive control groups (10), an obese model group (24), and a vitamin-D-supplemented obese group (13). Aortic tissue samples and fasting blood samples were collected. The following biochemical investigations were performed: serum cholesterol, triglycerides, HDL-C, LDL-C, ALT, AST, CPK, CK-MB, and hs-cTnt. HOMA-IR was calculated. Moreover, serum SMP-30, 25 (OH)Vitamin D3, and eNOS were determined by the ELISA technique. Aortic gene expression of eNOS, SMP-30, and P53 was estimated by real-time qRT-PCR. Serum 25(OH) D3 and SMP-30 were lower in the obese group. In addition, the obese group showed higher serum lipid profile, HOMA-IR, eNOS, ALT, AST, CPK, CK-MB, and hs-cTnt than the control groups, while decreased levels were found in the vitamin-D-treated obese group. Gene expression of eNOS and SMP-30 were in accordance with their serum levels. A positive correlation was found between vitamin D level and SMP-30. In conclusion, obesity is associated with vitamin D deficiency and enhanced cellular senescence. They could play a role in the pathogenesis of obesity-associated subclinical atherosclerosis and endothelial dysfunction. Vitamin D supplements could play a protective role against such obesity-related comorbidity.

The relationship between circulating vitamin D3 and subclinical atherosclerosis in an elderly Asian population

The current evidence regarding the association between vitamin D deficiency and cardiovascular diseases/metabolic disorders is contradictory and inconclusive. In this large-scale observational study, we investigated the relationship between the serum 25-hydroxy vitamin D3 [25(OH)D] concentration and subclinical atherosclerosis in an elderly Asian population. In the I-Lan longitudinal study (ILAS), 1798 elderly, aged 50 and older, were enrolled. For each subject, serum 25-hydroxy vitamin D3 [25(OH)D] concentration and demographic data were recorded. The participants were divided into two groups according to their serum 25(OH)D level (sufficient, > 20 ng/mL and deficient, ≤ 20 ng/mL). Carotid intima-media thickness (cIMT) was measured at bilateral common carotid arteries. Subclinical atherosclerosis was defined as a mean cIMT > 0.81 mm. The mean subject age was 64 ± 9 years old, and 604 (33.6%) were identified as having serum 25(OH)D level ≤ 20 ng/mL. Subjects with serum 25(OH)D level ≤ 20 ng/mL were younger, more likely to be female and smoker, and had a higher incidence of hypertension, dyslipidemia, and metabolic syndrome, compared to those with serum 25(OH)D level > 20 ng/mL. Additionally, patients with serum 25(OH)D level ≤ 20 ng/mL were associated with a lower risk of subclinical atherosclerosis (crude OR: 0.63, 95% CI 0.50–0.81, p < 0.001), according to univariate analysis. However, after adjusting for gender and age, serum 25(OH)D level ≤ 20 ng/mL was not a significant risk factor for subclinical atherosclerosis. Serum 25(OH)D level ≤ 20 ng/mL was not an independent risk factor for subclinical atherosclerosis in this large elderly Asian population. Association observed in the univariate analysis may be confounded by gender or comorbidities.

Low vitamin D is associated with coronary atherosclerosis in women with HIV

BACKGROUND

Vitamin D deficiency is underdiagnosed and undertreated, especially among people living with HIV (PLWH). Recently, there has been an increased interest in the role of vitamin D in cardiovascular disease (CVD). While vitamin D deficiency has been associated with CVD in observational studies in the general population, there are limited data in PLWH. We therefore performed an analysis to assess the relationship of vitamin D and coronary atherosclerosis using coronary CT angiography (CCTA).

METHODS

Women living with HIV (WLWH) without known CVD were included. Based on the median value of serum vitamin D levels, participants were dichotomized to either the <25 ng/ml (lower vitamin D group) or ≥25 ng/ml (higher vitamin D group). CCTA was used to assess plaque characteristics.

RESULTS

Forty-three WLWH were included in the analyses (mean age 46 ±8 years, 56% African American, duration of HIV 15 ±6 years, 83% undetectable HIV viral load). WLWH in the lower vitamin D group (n=22) had significantly higher numbers of segments with any coronary plaque (2.27 ±3.01 versus 0.38 ±0.97; P=0.02) and segments with non-calcified coronary plaque (1.41 ±1.82 versus 0.29 ±0.64; P=0.03) compared with WLWH in the higher vitamin D group (n=21). After adjusting for Framingham CHD risk point score, body mass index, diabetes and race, the relationship remained significant.

CONCLUSIONS

Our study demonstrates a significant, independent relationship between lower vitamin D status and higher numbers of noncalcified coronary plaque segments in WLWH. Further studies are warranted to evaluate the effect of vitamin D on CVD in PLWH. Trial Registration Identifier: NCT00455793.

Decreased ratio of influenza-specific IgG versus IgM in response to influenza vaccination in antiretroviral-treated HIV-infected African Americans compared to Caucasians, and its direct correlation with the percentages of peripheral Tfh cells

BACKGROUND

Racial differences have been observed in the rate of bacterial infection and disease progression in HIV. Here, we evaluate racial differences in seasonal influenza vaccine responses.

METHODS

16 healthy controls (9 Caucasians (CC) and 7 African Americans (AA)) and 26 antiretroviral therapy (ART)-treated aviremic HIV+ subjects (11 CC and 15 AA) were enrolled in the current study. Blood was collected at pre-vaccination (D0) and day 14 (D14) following seasonal influenza vaccination. Serologic responses were characterized in plasma by ELISA. B and T cells were assessed by flow cytometry ex vivo.

RESULTS

The absolute counts of CD4+ CD3+ T cells and CD19+ B cells were similar in healthy controls and HIV-infected individuals, and similar in CC and AA in the two study groups. However, the percentage of peripheral T follicular helper (pTfh) cells was decreased in HIV+ AA compared to HIV+ CC. There were no racial differences in IgG antibody responses against vaccination in the two study groups. However, the ratio of anti-influenza-specific IgG versus IgM induction following vaccination was decreased in HIV+ AA compared to HIV+ CC, which was directly correlated with the percentages of pTfh cells. This racial difference and correlation were not demonstrable in healthy controls.

CONCLUSION

Here we report that HIV + AA has decreased fold induction of IgG versus IgM after influenza vaccination, which may suggest impaired class-switching from IgM to IgG in AA HIV-infected individuals.

Serum 25-Hydroxyvitamin D Concentrations from Patient Groups at High Risk for Deficiency

BACKGROUND

Deficiency of 25-hydroxyvitamin D in serum is endemic in the general population, and testing for this hormone is useful in accessing a patient's overall health and well-being.

METHODS

We obtained blood from 216 hospitalized patients and outpatients divided into 4 groups thought to be at high risk of 25-hydroxyvitamin D deficiency: homeless, recreational drug abusers, psychiatric patients with limited access to the outdoors, and those infected with HIV. The 25-hydroxyvitamin D concentrations from these patients were determined with 2 different methodologies (immunoassay and mass spectrometry) and compared against 25-hydroxyvitamin D concentrations in apparently healthy controls. We hypothesized that these groups may be at higher risk for vitamin D deficiency because of poor nutrition, inadequate housing, restricted access to outdoors, or the presence of chronic disease.

RESULTS

For each of the patient groups including healthy controls, the median concentration of 25-hydroxyvitamin D was below 30 ng/mL, indicating deficiency. Comparisons between the healthy controls and the other groups were not statistically significant with either methodology, except for the homeless patients in whom a higher number of individuals had 25-hydroxyvitamin D concentrations below 20 ng/mL. Results between the 2 testing platforms demonstrated that only 52% of the specimens analyzed by immunoassay agreed within ±10% of the LC-MS/MS results, with an overall correlation coefficient to 0.920. The degree of concordance for deficiency with 2 published cutoffs of 20 and 30 ng/mL was 91% and 91%, respectively.

CONCLUSIONS

Vitamin D deficiency is a common finding in all the populations studied. The Lumipulse^® G vitamin D immunoassay is an alternative for detecting vitamin D deficiency.

Mendelian Randomization Studies Do Not Support a Role for Vitamin D in Coronary Artery Disease

BACKGROUND

Observational studies support a possible association between decreased vitamin D levels and risk of coronary artery disease (CAD); however, it remains unclear whether this relationship is causal. We aimed to evaluate whether genetically lowered vitamin D levels influence the risk of CAD using a Mendelian randomization approach.

METHODS AND RESULTS

In this 2-stage Mendelian randomization study, we first identified single-nucleotide polymorphisms associated with 25-hydroxyvitamin D (25OHD) levels in the SUNLIGHT consortium (n=33 996), then tested them for possible violation of Mendelian randomization assumptions. A count of risk alleles was tested for association with 25OHD levels in a separate cohort (n=2347). Alleles were weighted by their relative effect on 25OHD and tested for their combined effect on CAD in the Coronary Artery Disease Genome-Wide Replication and Meta-Analysis (CARDIoGRAM) study (22 233 cases/64 762 controls). Four single-nucleotide polymorphisms were identified to be associated with 25OHD levels, all in or near genes implicated in 25OHD synthesis, transport or metabolism. A count of these risk alleles was strongly associated with 25OHD (n=2347, F-test statistic=49.7, P=2×10(-12)). None of the single-nucleotide polymorphisms associated with 25OHD levels were associated with CAD (all P values >0.6). The Mendelian randomization odds ratio (OR) for CAD was 0.99 (95% confidence interval, 0.84-1.17; P=0.93; I(2)=0) per SD decrease in log-transformed 25OHD levels. These results persisted after sensitivity analyses for population stratification and pleiotropy.

CONCLUSIONS

Genetically lowered 25OHD levels were not associated with increased risk of CAD in a large, well-powered study, suggesting that previous associations between circulating 25OHD levels and CAD are possibly confounded or due to reverse causation.

Relationship between serum vitamin D levels and angiographic severity and extent of coronary artery disease

BACKGROUND

Vitamin D is known for its effect in calcium and bone homeostasis. There is an increasing evidence for health benefits accomplished by activated vitamin D that go beyond these classical functions. Previous studies have suggested that lower vitamin D levels are associated with increased cardiovascular disease risk. Therefore, we aimed to evaluate relationship between vitamin D levels and extent and severity of coronary artery disease.

MATERIALS AND METHODS

A total of 746 patients in whom coronary angiography was performed between August 2012 and July 2013 were enrolled in this study. Serum vitamin D levels were measured, and patients were grouped according to their serum vitamin D levels (vitamin D <20 ng/mL (n = 602) Group 1 versus >20 ng/dL (n = 144) Group 2). Gensini score system was used to evaluate the association between serum vitamin D levels and severity and extent of coronary artery disease.

RESULTS

There was no significant difference between the groups in terms of baseline characteristics and demographic characteristics. Mean serum vitamin D levels of all patient cohort was 15.54 ± 7.46 ng/mL. Group 1 and Group 2 had an average serum vitamin D levels of 12.6 ± 3.3 ng/mL and 27.5 ± 7.8 ng/mL, respectively. Gensini score for all cohort was 26.25 ± 34.32. Group 1 had an average Gensini score of 26.4 ± 35.7; on the other hand, Gensini score was 25.5 ± 27.5 in Group 2 (P = 0.097).

CONCLUSIONS

This study failed to demonstrate significant relationship between serum vitamin D levels and the severity and extent of coronary artery disease. Further studies with more participation and homogenous groups with comparable individual and environmental features are needed to evaluate the association of serum vitamin D levels and cardiovascular diseases.

Circulating vitamin D levels are associated with the presence and severity of coronary artery disease but not peripheral arterial disease in patients undergoing coronary angiography

BACKGROUND AND AIMS

To investigate the association between vitamin D levels, angiographic severity of coronary artery disease, arterial stiffness and degree of peripheral arterial disease (PAD) as assessed by ankle brachial index (ABI).

METHODS AND RESULTS

375 patients undergoing coronary angiography from November 2012 to September 2013 were recruited. Serum 25-hydroxyvitamin D (25OHD) levels were measured as were ABI and pulse wave velocity (PWV). Based on the findings of the coronary angiogram, patients were divided into subgroups: Absent, Single, Double and Triple Vessel Disease (as defined by >50% stenosis in each major coronary artery) 0.275 patients not taking vitamin D supplements were included in the analysis. Mean age was 66.0 ± 11.2 (mean ± SD) years. Levels of 25(OH)D were significantly lower in patients with CAD when compared to patients without CAD (57.0 ± 1.73 versus 70.1 ± 2.46 nmol/L; p < 0.01). One way ANOVA revealed triple vessel disease patients had significantly lower 25(OH)D levels when compared to single vessel disease patients (50.6 ± 2.84 nmol/L versus 61.3 ± 3.16 p < 0.01) and trended to be lower when compared to double vessel disease patients (50.6 ± 2.84 versus 59.0 ± 2.99 nmol/L; p = 0.07). Stepwise regression revealed that age, gender (male), hypertension, hyperlipidemia and 25(OH)D were significant predictors of CAD (p < 0.05). Vitamin D was the most significant predictor for CAD (p < 0.001) There was no correlation between 25(OH)D levels, ABI and PWV.

CONCLUSION

Among patients presenting for coronary angiography, low serum 25-hydroxyvitamin D levels are associated with the presence and extent of angiographic CAD but not arterial stiffness or PAD.

Association between serum vitamin D levels and subclinical coronary atherosclerosis and plaque burden/composition in young adult population

Evidence suggests that low 25-OH vitamin D 25(OH)D concentrations may increase the risk of several cardiovascular diseases such as hypertension, peripheral vascular disease, diabetes mellitus, obesity, myocardial infarction, heart failure and cardiovascular mortality. Recent studies suggested a possible relationship between vitamin D deficiency and increased carotid intima-media wall thickness and vascular calcification. We hypothesized that low 25(OH)D may be associated with coronary atherosclerosis and coronary plaque burden and composition, and investigated the relationship between serum vitamin D levels and coronary atherosclerosis, plaque burden or structure, in young adult patients by using dual-source 128x2 slice coronary computed tomography angiography (CCTA). We included 98 patients with coronary atherosclerosis and 110, age and gender matched, subjects with normal findings on CCTA examinations. Patients with subclinical atherosclerosis had significantly higher serum total cholesterol, triglycerides, hs-CRP, uric acid, HbA1c and creatinine levels and lower serum 25(OH)D levels in comparison with controls. There was no significant correlation between 25(OH)D and plaque morphology. There was also a positive relationship between 25(OH)D and plaque burden of coronary atherosclerosis. In multivariate analysis, coronary atherosclerosis was associated high hs-CRP (adjusted OR: 2.832), uric acid (adjusted OR: 3.671) and low 25(OH)D (adjusted OR: 0.689). Low levels of 25(OH)D were associated with coronary atherosclerosis and plaque burden, but there was no significant correlation between 25(OH)D and plaque morphology.

The causal effect of vitamin D binding protein (DBP) levels on calcemic and cardiometabolic diseases: a Mendelian randomization study

BACKGROUND

Observational studies have shown that vitamin D binding protein (DBP) levels, a key determinant of 25-hydroxy-vitamin D (25OHD) levels, and 25OHD levels themselves both associate with risk of disease. If 25OHD levels have a causal influence on disease, and DBP lies in this causal pathway, then DBP levels should likewise be causally associated with disease. We undertook a Mendelian randomization study to determine whether DBP levels have causal effects on common calcemic and cardiometabolic disease.

METHODS AND FINDINGS

We measured DBP and 25OHD levels in 2,254 individuals, followed for up to 10 y, in the Canadian Multicentre Osteoporosis Study (CaMos). Using the single nucleotide polymorphism rs2282679 as an instrumental variable, we applied Mendelian randomization methods to determine the causal effect of DBP on calcemic (osteoporosis and hyperparathyroidism) and cardiometabolic diseases (hypertension, type 2 diabetes, coronary artery disease, and stroke) and related traits, first in CaMos and then in large-scale genome-wide association study consortia. The effect allele was associated with an age- and sex-adjusted decrease in DBP level of 27.4 mg/l (95% CI 24.7, 30.0; n = 2,254). DBP had a strong observational and causal association with 25OHD levels (p = 3.2 × 10(-19)). While DBP levels were observationally associated with calcium and body mass index (BMI), these associations were not supported by causal analyses. Despite well-powered sample sizes from consortia, there were no associations of rs2282679 with any other traits and diseases: fasting glucose (0.00 mmol/l [95% CI -0.01, 0.01]; p = 1.00; n = 46,186); fasting insulin (0.01 pmol/l [95% CI -0.00, 0.01,]; p = 0.22; n = 46,186); BMI (0.00 kg/m(2) [95% CI -0.01, 0.01]; p = 0.80; n = 127,587); bone mineral density (0.01 g/cm(2) [95% CI -0.01, 0.03]; p = 0.36; n = 32,961); mean arterial pressure (-0.06 mm Hg [95% CI -0.19, 0.07]); p = 0.36; n = 28,775); ischemic stroke (odds ratio [OR]  = 1.00 [95% CI 0.97, 1.04]; p = 0.92; n = 12,389/62,004 cases/controls); coronary artery disease (OR = 1.02 [95% CI 0.99, 1.05]; p = 0.31; n = 22,233/64,762); or type 2 diabetes (OR = 1.01 [95% CI 0.97, 1.05]; p = 0.76; n = 9,580/53,810).

CONCLUSIONS

DBP has no demonstrable causal effect on any of the diseases or traits investigated here, except 25OHD levels. It remains to be determined whether 25OHD has a causal effect on these outcomes independent of DBP. Please see later in the article for the Editors' Summary.

Vitamin D receptor signaling in renal and cardiovascular protection

The high prevalence of vitamin D deficiency in patients with chronic kidney disease is believed to be an important risk factor for the cardiorenal syndrome commonly seen in this patient population. African Americans suffer a disproportionally high incidence of renal and cardiovascular disease with poor disease outcome, which may be partly attributed to their low vitamin D status in part owing to low subcutaneous photoproduction of vitamin D. Mounting evidence from animal and clinical studies has shown beneficial effects of vitamin D therapy on the renal and cardiovascular systems, and the underlying renoprotective and cardioprotective mechanisms of vitamin D receptor (VDR)-mediated signaling are under intense investigation. In this article, our most recent understanding of the renal protective mechanism of the podocyte VDR signaling against diabetic nephropathy and the anti-atherosclerotic role of macrophage VDR signaling in the regulation of atherosclerosis is reviewed.

Vitamin D deficiency and coronary artery disease: a review of the evidence

Coronary artery disease remains the leading cause of death in developed countries despite significant progress in primary prevention and treatment strategies. Older patients are at particularly high risk of poor outcomes following acute coronary syndrome and impaired nutrition, including low vitamin D levels, may play a role. The extraskeletal effects of vitamin D, in particular, its role in maintaining a healthy cardiovascular system are receiving increased attention. Longitudinal studies have demonstrated increased cardiovascular mortality and morbidity associated with vitamin D deficiency. Low vitamin D levels have been linked to inflammation, higher coronary artery calcium scores, impaired endothelial function and increased vascular stiffness. However, so far, few randomized controlled trials have investigated the potential benefits of vitamin D supplementation in preventing cardiovascular events, and most available trials have tested low doses of supplementation in relatively low-risk populations. Whether vitamin D supplementation will be beneficial among patients with coronary artery disease, including high risk older patients presenting with acute coronary syndrome, is unknown and warrants further investigation.

Vitamin D deficiency is associated with development of subclinical coronary artery disease in HIV-infected African American cocaine users with low Framingham-defined cardiovascular risk

Chronic cocaine use may lead to premature atherosclerosis, but the prevalence of and risk factors for coronary artery disease (CAD) in asymptomatic cocaine users have not been reported. The objective of this study was to examine whether vitamin D deficiency is associated with the development of CAD in human immunodeficiency virus (HIV)-infected African American cocaine users with low CAD risk.

METHODS

In this prospective follow-up study, we investigated 169 HIV-infected African American cocaine users with low Framingham risk at baseline. The main outcome measures were incidence of subclinical CAD and development of subclinical CAD.

RESULTS

Fifty of the 169 African Americans had evidence of subclinical disease on the initial cardiac computed tomography. A second cardiac computed tomography was performed on the 119 African Americans without disease on the first scan. The total sum of person-years of follow-up was 289.6. Subclinical CAD was detected in 11 of these, yielding an overall incidence of 3.80/100 person-years (95% confidence interval 1.90-6.80). Among the factors investigated, only vitamin D deficiency was independently associated with development of subclinical CAD. The study did not find significant associations between CD4 count, HIV viral load, or antiretroviral treatment use and the incidence of subclinical CAD. This study appears to suggest that there is a threshold level of vitamin D (10 ng/mL) above which the effect of vitamin D on subclinical CAD is diminished.

CONCLUSION

The incidence of subclinical CAD in HIV-infected African American cocaine users with low CAD risk is high, especially in those with vitamin D deficiency. Well designed randomized clinical trials are warranted to confirm the role of vitamin D deficiency in the development of CAD in HIV-infected African American cocaine users with low CAD risk.

Vitamin D deficiency is associated with the development of subclinical coronary artery disease in African Americans with HIV infection: a preliminary study

BACKGROUND

Premature coronary artery disease (CAD) is a major concern in human immunodeficiency virus (HIV)-infected African Americans. The objectives of the study were to estimate the incidence of subclinical CAD, defined by the presence of coronary plaque and/or calcification on cardiac computed tomography (CT), and to identify the associated risk factors in this vulnerable population.

SUBJECTS AND METHODS

Between August 2003 and September 2010, 188 HIV-infected African Americans without known, or symptoms of, CAD underwent cardiac CT. The subset without demonstrable disease underwent a second cardiac CT approximately 2 years later. The incidence of disease over that period and the effects of antiretroviral treatment and other known and hypothesized risk factors were investigated.

RESULTS

Sixty-nine of these 188 African Americans had evidence of subclinical disease on the initial cardiac CT, confirming prior high prevalence reports. A second cardiac CT was performed on 119 African Americans without disease approximately 2 years later. The total person-years of follow-up was 284.4. Subclinical CAD was detected in 14 of these, yielding an overall incidence of 4.92/100 person-years (95% confidence interval, 2.69-8.26). Among the factors investigated, only male sex and vitamin D deficiency were independently associated with the development of subclinical CAD. The study did not find significant associations between CD4 count, HIV viral load, antiretroviral treatment use, or cocaine use and the incidence of subclinical CAD.

CONCLUSIONS

The incidence of subclinical CAD in African Americans with HIV infection is provocatively high. Larger studies are warranted to confirm the role of vitamin D deficiency in the development of CAD in HIV-infected African Americans.

Vitamin D deficiency is associated with coronary artery calcification in cardiovascularly asymptomatic African Americans with HIV infection

OBJECTIVE

Patients with HIV infection are at increased risk for coronary artery disease (CAD), and growing evidence suggests a possible link between vitamin D deficiency and clinical/subclinical CAD. However, the relationship between vitamin D deficiency and coronary artery calcification (CAC), a sensitive marker for subclinical CAD, in those with HIV infection is not well investigated.

METHODS

CAC was quantified using a Siemens Cardiac 64 scanner, and vitamin D levels and the presence of traditional and novel risk factors for CAD were obtained in 846 HIV-infected African American (AA) participants aged 25 years or older in Baltimore, MD, USA without symptoms or clinical evidence of CAD.

RESULTS

The prevalence of vitamin D deficiency (25-hydroxy vitamin D <10 ng/mL) was 18.7%. CAC was present in 238 (28.1%) of the 846 participants. Logistic regression analysis revealed that the following factors were independently associated with CAC: age (adjusted odds ratio [OR]: 1.11; 95% confidence interval [CI]: 1.08-1.14); male sex (adjusted OR: 1.71; 95% CI: 1.18-2.49); family history of CAD (adjusted OR: 1.53; 95% CI: 1.05-2.23); total cholesterol (adjusted OR: 1.006; 95% CI: 1.002-1.010); high-density lipoprotein cholesterol (adjusted OR: 0.989; 95% CI: 0.979-0.999); years of cocaine use (adjusted OR: 1.02; 95% CI: 1.001-1.04); duration of exposure to protease inhibitors (adjusted OR: 1.004; 95% CI: 1.001-1.007); and vitamin D deficiency (adjusted OR: 1.98; 95% CI: 1.31-3.00).

CONCLUSION

Both vitamin D deficiency and CAC are prevalent in AAs with HIV infection. In order to reduce the risk for CAD in HIV-infected AAs, vitamin D levels should be closely monitored. These data also suggest that clinical trials should be conducted to examine whether vitamin D supplementations reduce the risk of CAD in this AA population.

Vitamin D receptor signaling inhibits atherosclerosis in mice

Although vitamin D has been implicated in cardiovascular protection, few studies have addressed the role of vitamin D receptor (VDR) in atherosclerosis. Here we investigate the effect of inactivation of the VDR signaling on atherogenesis and the antiatherosclerotic mechanism of vitamin D. Low density lipoprotein receptor (LDLR)(-/-)/VDR(-/-) mice exhibited site-specific accelerated atherogenesis, accompanied by increases in adhesion molecules and proinflammatory cytokines in the aorta and cholesterol influx in macrophages. Macrophages showed marked renin up-regulation in the absence of VDR, and inhibition of renin by aliskiren reduced atherosclerosis in LDLR(-/-)/VDR(-/-) mice, suggesting that the renin-angiotensin system (RAS) promotes atherosclerosis in the absence of VDR. LDLR(-/-) mice receiving LDLR(-/-)/VDR(-/-) BMT developed larger lesions than LDLR(-/-) BMT controls. Moreover, LDLR(-/-) mice receiving Rag-1(-/-)/VDR(-/-) BMT, which were unable to generate functional T and B lymphocytes, still had more severe atherosclerosis than Rag-1(-/-) BMT controls, suggesting a critical role of macrophage VDR signaling in atherosclerotic suppression. Aliskiren treatment eliminated the difference in lesions between Rag-1(-/-)/VDR(-/-) BMT and Rag-1(-/-) BMT recipients, indicating that local RAS activation in macrophages contributes to the enhanced atherogenesis seen in Rag-1(-/-)/VDR(-/-) BMT mice. Taken together, these observations provide evidence that macrophage VDR signaling, in part by suppressing the local RAS, inhibits atherosclerosis in mice.

Vitamin D: roles in renal and cardiovascular protection

PURPOSE OF REVIEW

Great progress has been made in recent years in understanding the expanding roles of the vitamin D endocrine system beyond calcemic regulation, including pathophysiological actions in the kidney and the cardiovascular system. The purpose of this review is to update the recent advance regarding the effects of vitamin D and its analogs on the renal and cardiovascular system.

RECENT FINDINGS

Vitamin D deficiency is not only widely associated with chronic kidney disease and cardiovascular disease in humans, but may also accelerate the disease progression. Dysregulation of vitamin D metabolism caused by renal insufficiency contributes to the low vitamin D status. Preclinical and clinical studies have demonstrated impressive therapeutic outcome with low-calcemic vitamin D analogs in renal and cardiovascular disease. The mechanism underlying the renal and cardiovascular protection involves regulation of multiple signaling pathways by vitamin D including nuclear factor κB, Wnt/β-catenin and the renin-angiotensin system.

SUMMARY

The renal and cardiovascular protective activity of vitamin D revealed in recent studies has profound clinical implications. Nutritional correction of vitamin D deficiency and treatment with vitamin D analogs could be therapeutic options for renal and cardiovascular problems. New vitamin D analogs with better renal and cardiovascular therapeutic efficacy are highly desired. More randomized trials are needed to address these issues.

Vitamin D deficiency is associated with silent coronary artery disease in cardiovascularly asymptomatic African Americans with HIV infection

BACKGROUND

Growing evidence suggests that vitamin D deficiency Is associated with clinical coronary artery disease (CAD). The relationship between vitamin D deficiency and subclinical CAD in HIV-infected individuals is not well-characterized.

METHODS

Computed tomographic (CT) coronary angiography was performed using contrast-enhanced 64-slice multidetector CT imaging, and vitamin D levels and the presence of traditional and novel risk factor for CAD were obtained in 674 HIV-infected African American (AA) participants aged 25-54 years in Baltimore, MD, without symptoms/clinical evidence of CAD.

RESULTS

The prevalence of vitamin D deficiency (25-hydroxy vitamin D <10 ng/mL) was 20.0% (95% confidence interval [CI], 16.9-23.1). Significant (≥50%) coronary stenosis was present in 64 (9.5%) of 674 participants. Multiple logistic regression analysis revealed that male gender (adjusted odds ratio [OR], 2.19; 95% CI, 1.17-4.10), diastolic BP ≥85 mmHg (adjusted OR: 1.94, 95% CI: 1.02 -3.68), low-density lipoprotein cholesterol ≥100 mg/dL (adjusted OR, 1.95; 95% CI, 1.13-3.36), cocaine use for ≥15 years (adjusted OR, 1.77; 95% CI, 1.01-3.10), use of antiretroviral therapies for ≥6 months (adjusted OR, 2.26; 95% CI, 1.17-4.36), year of enrollment after 2005 (adjusted ORs for 2006-2007, 2008-2009, and 2010 were 0.32 [95% CI, 0.13-0.76], 0.26 [95% CI, 0.12-0.56], and 0.32 (95% CI, 0.15-0.65], respectively), and vitamin D deficiency (adjusted OR, 2.28; 95% CI, 1.23-4.21) were independently associated with significant coronary stenosis.

CONCLUSIONS

Both vitamin D deficiency and silent CAD are prevalent in HIV-infected AAs. In addition to management of traditional CAD risk factors and substance abuse, vitamin D deficiency should be evaluated in HIV-infected AAs. These data support the conduct of a prospective trial of vitamin D in this high-risk patient population.