Review of metabolic, immunologic, and virologic consequences of suboptimal vitamin D levels in HIV infection

The Role of Vitamin D in Respiratory Viral Infections and Other Infectious Diseases

Clinical studies and meta-analyzes have shown that reduced levels of 25 (OH) D in the blood contribute to impaired immunity and stimulate excessive inflammation that adversely affects the health of children: the risk of developing bronchial asthma (BA), obstructive bronchitis, and allergic rhinitis increases. The main purpose of this review is to summarize the current literature data on the relationship between vitamin D, VRI and other infectious diseases with a clinical example.

Vitamin D Status and Kidney Function Decline in HIV-Infected Men: A Longitudinal Study in the Multicenter AIDS Cohort Study

Vitamin D may play an important role in a range of disease processes. In the general population, lower vitamin D levels have been associated with kidney dysfunction. HIV-infected populations have a higher risk of chronic kidney disease. Few studies have examined the link between lower vitamin D levels and kidney function decline among HIV-infected persons. We investigated the associations of serum 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)₂D] with kidney function decline in a cohort of HIV-infected white and black men under highly active antiretroviral therapy treatment in the vitamin D ancillary study of the Multicenter AIDS Cohort Study. The associations of 25(OH)D and 1,25(OH)₂D with annual change in estimated glomerular filtration rate (eGFR) were evaluated using linear mixed effects models. This study included 187 whites and 86 blacks with vitamin D measures and eGFR ≥60 ml/min/1.73 m² at baseline. Over a median follow-up of 8.0 years, lower 25(OH)D levels were significantly associated with faster eGFR decline in whites (adjusted annual change in eGFR, tertile 1: -2.06 ml/min/1.73 m² vs. tertile 3: -1.23 ml/min/1.73 m², p trend .03), while no significant association was detected in blacks. Lower 1,25(OH)₂D was associated with faster kidney function decline in both whites and blacks, although the estimates were not statistically significant. In conclusion, lower 25(OH)D levels were significantly associated with faster eGFR decline in a cohort of HIV-infected white men, but not in those with black ancestry. Further research is warranted to investigate the association of 25(OH)D and 1,25(OH)₂D with kidney function decline in larger and ethnically diverse populations.

Bone mineral density and vitamin D concentration: the challenges in taking care of children and adolescents infected with HIV

BACKGROUND

The increase in life expectancy for patients living with human immunodeficiency virus (HIV) infection has resulted in health complications related to a chronic disease.

OBJECTIVES

To evaluate the prevalence of bone mineral density (BMD) alterations and vitamin D concentrations in HIV-infected children and adolescents and to verify the variations in those parameters during a 12-month interval.

METHODS

A prospective cohort study with a dual period of evaluation was conducted in 57 patients perinatally HIV-infected and one patient with sexual abuse in early infancy. Demographic, anthropometric, pubertal stage, viral load, T CD4+ cell count and antiretroviral therapy were evaluated. Biochemical tests and total body (TB) and lumbar spine (L1-L4) bone density evaluations by dual X-ray absorptiometry (DXA) were performed. Calcium or vitamin D supplements were prescribed if reduction in BMD or deficiency for vitamin D was detected.

RESULTS

58 patients (ages 5.4-18.3 years; 60.3% girls) were included (T0); 55 patients were reevaluated after 12 (±3) months (T1). Low bone mass for chronological age was found in 6/58 (10.4%) and 6/55(10.9%) patients at T0 and at T1, respectively. There was no statistical relationship between z-scores for BMD (BMD z-score) and the variables sex, fracture history, family history of osteoporosis, physical activity and pubertal stage. There was a relation between BMD z-score alterations for TB and HIV viral load at T1 (p=0.016). There was no association between duration or classes of antiretroviral therapy and bone density. The mean value of vitamin D in T0 was 23.43ng/mL±2.015 and in T1 22.1ng/mL±0.707 and considered insufficient levels for this population.

CONCLUSION

Patients infected with HIV are at risk for BMD alterations and lower vitamin D serum concentrations; both of these variables should be evaluated at routine examinations in order to improve both prevention and therapeutic planning.

Adiponectin, Leptin and Inflammatory Markers in HIV-associated Metabolic Syndrome in Children and Adolescents

BACKGROUND

Metabolic syndrome (MetS) is more common in HIV-infected adults and children than in the general population. Adipocytokines and inflammatory markers may contribute to the pathophysiology of this condition and could be useful indices for monitoring MetS. The objective of this study was to provide information on the prevalence of MetS and investigate the role of adipocytokines and other biomarkers in this syndrome in HIV-infected pediatric patients.

METHODS

A cross-sectional study was conducted between October 2013 and March 2014 in the outpatient clinics of 2 tertiary pediatric referral hospitals. Fifty-four HIV-infected children and adolescents were included. MetS was defined according to the International Diabetes Federation and modified National Cholesterol Education Program Adult Treatment Panel III criteria. Measurements included anthropometry, waist circumference, blood pressure, fasting lipids, glucose and insulin, adiponectin, leptin, interleukin-6, vitamin D and C-reactive protein and clinical lipodystrophy assessment.

RESULTS

Among the total, 3.7% of patients met the International Diabetes Federation criteria for MetS and 7.4% met the National Cholesterol Education Program Adult Treatment Panel III criteria. C-reactive protein and leptin levels were significantly higher and adiponectin level significantly lower in patients with MetS, regardless of the criteria used. Insulin resistance was observed in 40.7% of patients; abnormal quantitative insulin sensitivity check index values were found in 88.9%. Eighteen patients (33.3%) had vitamin D deficiency.

CONCLUSIONS

The prevalence of MetS was similar to that observed in larger cohorts of HIV-infected patients in our setting. Adipocytokine dysregulation seems to be related to MetS in HIV-infected children. A high percentage of patients showed insulin resistance, which should be strictly monitored.

Environmental Factors Related to Pulmonary Tuberculosis in HIV-Infected Patients in the Combined Antiretroviral Therapy (cART) Era

The aim of our study was to evaluate the seasonal variations and whether short-term exposure to environmental risk factors, such as climate and air pollution, is associated with PTB-related hospital admissions in human immunodeficiency virus (HIV)-infected patients in Spain during the era of combined antiretroviral therapy (cART). A retrospective study was carried out using data from the Minimum Basic Data Set (MBDS) and the State Meteorological Agency (AEMET) of Spain. The primary outcome variable was hospital admissions with PTB diagnosis. The environmental risk factors evaluated were season, temperature, humidity, NO2, SO2, O3, PM10, and CO. Overall, HIV-infected patients had a lower frequency of PTB-related hospital admissions in summer (22.8%) and autumn (22.4%), but higher values in winter (26.6%) and spring (28.2%). Using a Bayesian temporal model, PTB-related hospital admissions were less frequent in summer-autumn and more abundant in winter-spring during the first years of follow-up. During the later years of follow-up, the seasonal trends continued resulting in the lowest values in autumn and the highest in spring. When considering short-term exposure to environmental risk factors, lower temperatures at 1 week (odds ratio (OR) = 1.03; p = 0.008), 1.5 weeks (OR = 1.03; p<0.001), 2 weeks (OR = 1.04; p<0.001), and 3 weeks (OR = 1.03; p<0.001) prior to PTB admission. In addition, higher concentration of NO2 at the time of admission were significantly associated with higher likelihoods of PTB-related hospital admission in HIV-infected patients when 1.5 weeks (OR = 1.1; p = 0.044) and 2 weeks (OR = 1.21; p<0.001) were used as controls. Finally, higher concentration of SO2 at 1.5 weeks prior to PTB admission was significantly associated with a higher likelihood of PTB-related hospital admissions (OR = 0.92; p = 0.029). In conclusion, our data suggest an apparent seasonal variation in hospital admissions of HIV-infected patients with a PTB diagnosis (summer/autumn vs. winter/spring), as well as a link to short-term exposure to environmental risk factors, such as temperature and ambient NO2 and SO2.

Optimal vitamin D plasma levels are associated with lower bacterial DNA translocation in HIV/hepatitis c virus coinfected patients

OBJECTIVE

Vitamin D has been linked to the immune response modulation and the integrity of the intestinal mucosal barrier. Therefore, vitamin D might be involved in bacterial translocation related to HIV infection. Our major aim was to analyze the association between plasma levels of 25-hydroxy-vitamin D [25(OH)D] and bacterial 16S ribosomal DNA (bactDNA) in 120 HIV/hepatitis c virus (HCV) coinfected patients.

DESIGN

Cross-sectional study.

METHODS

Plasma 25(OH)D levels were quantified by enzyme immunoassay. The vitamin D status was defined as deficient (<25 nmol/l), insufficient (25-74 nmol/l), and optimal (≥75 nmol/l) plasma levels. Plasma bactDNA levels were measured by quantitative real-time PCR. For bactDNA levels the cutoffs used were as follows: low [<p25th (46 copies/μl)], moderate [p25th to p50th (78 copies/μl)], high [p50th to p75th (159 copies/μl)], and very high (>p75th).

RESULTS

Eighteen (15%) patients had 25(OH)D deficiency, 93 (77.5%) had insufficiency and nine (7.5%) had 25(OH)D optimal values. The bactDNA levels were lower in patients with 25(OH)D at least 75 nmol/l [37 copies/μl] than in patients with 25(OH)D insufficiency [84.2 copies/μl; P = 0.042]. Conversely, low bactDNA levels (<p25th) were found in 66.7% of patients with 25(OH)D optimal levels, whereas bactDNA levels above p25th were found only in 11.1% of them (P = 0.029). The plasma 25(OH)D not less than 75 nmol/l was associated with low bactDNA levels (<p25th) [adjusted OR = 8.13 (95% confidence interval = 1.82; 36.67); P = 0.006)]. The patients with optimal vitamin D status [25(OH)D ≥75 nmol/l] had lower plasma levels of CCL7 (P = 0.047) and basic fibroblast growth factor (P = 0.042).

CONCLUSION

The optimal vitamin D status was associated with low bacterial translocation and inflammation in HIV/HCV coinfected patients.

PTH and Vitamin D

PTH and Vitamin D are two major regulators of mineral metabolism. They play critical roles in the maintenance of calcium and phosphate homeostasis as well as the development and maintenance of bone health. PTH and Vitamin D form a tightly controlled feedback cycle, PTH being a major stimulator of vitamin D synthesis in the kidney while vitamin D exerts negative feedback on PTH secretion. The major function of PTH and major physiologic regulator is circulating ionized calcium. The effects of PTH on gut, kidney, and bone serve to maintain serum calcium within a tight range. PTH has a reciprocal effect on phosphate metabolism. In contrast, vitamin D has a stimulatory effect on both calcium and phosphate homeostasis, playing a key role in providing adequate mineral for normal bone formation. Both hormones act in concert with the more recently discovered FGF23 and klotho, hormones involved predominantly in phosphate metabolism, which also participate in this closely knit feedback circuit. Of great interest are recent studies demonstrating effects of both PTH and vitamin D on the cardiovascular system. Hyperparathyroidism and vitamin D deficiency have been implicated in a variety of cardiovascular disorders including hypertension, atherosclerosis, vascular calcification, and kidney failure. Both hormones have direct effects on the endothelium, heart, and other vascular structures. How these effects of PTH and vitamin D interface with the regulation of bone formation are the subject of intense investigation.

Increase of 25-hydroxyvitamin D levels after initiation of combination antiretroviral therapy

Although vitamin D deficiency in HIV patients reported worldwide, the mechanisms and the effect of combination antiretroviral therapy (cART) on vitamin D levels are unclear. Patients were 50 male Japanese with HIV who visited Teikyo University Hospital, Tokyo, Japan. Patients were divided into those receiving cART (cART-experienced group, n = 30) and those who had not received cART (cART-naïve group, n = 20). Patients in the cART-experienced group had received treatment with cART for more than one year and those in the cART-naïve group were just about to start cART at study entry. Patients underwent measurement of serum 25-hydroxyvitamin D (25(OH)D) levels and assessment of clinical factors twice at one year intervals. At study entry, 23 (76.7%) in the cART-experienced group and 19 (95.0%) in the cART-naïve group had vitamin D insufficiency or deficiency. Mean 25(OH)D values were significantly higher in the cART-experienced group (25.2 ng/ml vs. 19.3 ng/ml, p = 0.01). However, levels of 25(OH)D at one year increased more in the cART-naïve group (-1.1 ng/ml vs. 5.0 ng/ml, p = 0.01), with mean 25(OH)D values in the cART-naïve group increasing to match those in the cART-experienced group. HIV infected patients who initiated cART showed increases in vitamin D levels in one year.

An update on the association of vitamin D deficiency with common infectious diseases

Vitamin D plays an important role in modulating the immune response to infections. Deficiency of vitamin D is a common condition, affecting both the general population and patients in health care facilities. Over the last decade, an increasing body of evidence has shown an association between vitamin D deficiency and an increased risk for acquiring several infectious diseases, as well as poorer outcomes in vitamin D deficient patients with infections. This review details recent developments in understanding the role of vitamin D in immunity, the antibacterial actions of vitamin D, the association between vitamin D deficiency and common infections (like sepsis, pneumonia, influenza, methicillin-resistant Staphylococcus aureus, human immunodeficiency virus type-1 (HIV), and hepatitis C virus (HCV)), potential therapeutic implications for vitamin D replacement, and future research directions.

Prevalence of metabolic syndrome among antiretroviral-naive and antiretroviral-experienced HIV-1 infected Thai adults

Metabolic syndrome (MS), a group of interrelated risk factors for cardiovascular diseases (CVD) and type 2 diabetes, has been increasingly reported among HIV-infected patients. Data on the prevalence and risk factors for MS among HIV-1 infected Thai adults are limited. The study collected cross-sectional data from 580 HIV-1 infected adults-46.2% were men and 71% were antiretroviral therapy (ART)-experienced. The majority (78.8%) of them used non-nucleoside reverse transcriptase inhibitor-based regimens. Data on lipid profiles, fasting blood glucose, CD4 count, HIV RNA, antiretroviral therapy (ART), anthropometry, food intake, and exercise were recorded. MS was defined using American Heart Association/National Heart Lung and Blood Institute criteria. Overall prevalence of MS was 22.2%; 15.9% in ART-naïve group vs. 24.9% in ART-experienced group, p = 0.018. Significant risk factors for MS in multivariate analyses included age ≥35 years (odds ratio, OR, 4.2, 95%CI 1.6-11.0, p = 0.004), high cholesterol (OR 4.7, 95%CI 1.7-12.9, p = 0.002), and living outside Bangkok (OR 4.2, 95%CI 1.6-10.8, p = 0.003) in the ART-naïve group, and female gender (OR 1.7, 95%CI 1.0-2.8, p = 0.05), lipodystrophy (OR 1.8, 95%CI 1.0-3.0, p = 0.032), high cholesterol (OR 1.9, 95%CI 1.1-3.1, p = 0.015), and food insecurity (OR 1.8, 95%CI 1.0-3.3, p = 0.05) in the ART-experienced group. All variables, except for female gender in the ART-experienced group, remained significantly associated with MS in a model where lipodystrophy was excluded. We concluded that MS was common among HIV-1-infected Thai adults. As HIV-infected patients get older, early screening and intervention, such as ART modification to avoid lipodystrophy, may reduce MS and CVD-related morbidities and mortalities in long-term care.

Vitamin D deficiency is associated with severity of liver disease in HIV/HCV coinfected patients

OBJECTIVE

To study the association of plasma 25-hydroxy vitamin D (25(OH)D) levels in HIV/HCV coinfected patients with severity of liver disease and virological response to hepatitis C virus (HCV) therapy with pegylated-interferon-alpha plus ribavirin (pegIFNα/RBV).

METHODS

A cross-sectional study in 174 HIV/HCV coinfected patients that underwent a liver biopsy previously to start HCV therapy and a retrospective study of 125 of them. Plasma 25(OH)D levels were quantified by enzyme immunoassay. Liver biopsies were evaluated by METAVIR score. A sustained virological response (SVR) was defined as an undetectable serum HCV viral load (<10 IU/mL) up through 24 weeks after the end of HCV treatment.

RESULTS

The median of plasma 25(OH)D level was 48 nmol/L (p25th: 32.5; p75th: 56.1) and 27 (15.5%) had 25(OH)D deficiency (<25 nmol/L). The percentage of 25(OH)D deficiency was higher in patients with significant fibrosis (F ≥ 2) (92.6% vs. 57.1%; p = 0.010) and moderate necroinflammatory activity grade (A ≥ 2) (85.2% vs. 60%; p = 0.043). However, adjusted logistic regression analyses showed that 25(OH)D deficiency was only associated with severity of liver disease [F ≥ 2 (OR = 8.47 (95% of confidence interval (CI) = 1.88; 38.3); p = 0.005) and A ≥ 2 (OR = 3.25 (95%CI = 1.06; 10.1); p = 0.040)]. Moreover, any significant relationship was found between 25(OH)D deficiency and SVR after HCV therapy.

CONCLUSION

Plasma 25(OH)D deficiency was associated with liver disease severity in HIV/HCV coinfected patients, but it was not associated with HCV treatment failure.