Relationship of vitamin D insufficiency to AIDS-associated Kaposi's sarcoma outcomes: retrospective analysis of a prospective clinical trial in Zimbabwe

Immune Modulatory Effects of Vitamin D on Herpesvirus Infections

In addition to its classical role in calcium and phosphate metabolism regulation, vitamin D also has an important impact on immunity modulation. Vitamin D regulates the immune response, shifting from a proinflammatory state to a more tolerogenic one by increasing the release of anti-inflammatory cytokines while downregulating proinflammatory cytokines. Thus, low levels of vitamin D have been associated with an increased risk of developing autoimmune diseases like multiple sclerosis and type 1 diabetes. Furthermore, this prohormone also enhances the release of well-known antimicrobial peptides, like cathelicidin LL-37 and β-defensins; therefore, it has been proposed that vitamin D serum levels might be related to the risk of well-known pathogen infections, including herpesviruses. These are a group of widely spread viral pathogens that can cause severe encephalitis or tumors like Kaposi's sarcoma and Burkitt lymphoma. However, there is no consensus on the minimum levels of vitamin D or the recommended daily dose, making it difficult to establish a possible association between these two factors. This narrative non-systematic review will analyze the mechanisms by which vitamin D regulates the immune system and recent studies about whether there is an association between vitamin D serum levels and herpesvirus infections.

A real-world study of active vitamin D as a prognostic marker in patients with sarcoma

PURPOSE

The assessment of sarcoma during clinical practice is primarily based on imaging examination, with no effective biomarkers available. Although it has been established that 1,25(OH)2D3 is abnormally expressed in patients with sarcoma, it remains unclear whether 1,25(OH)2D3 level could be used as an evaluation marker in these patient population.

METHODS

This real-world study investigated 1,25(OH)2D3 level and its association with clinical features in sarcoma patients. Data on 1,25(OH)2D3, parathyroid hormone, calcium, and calcitonin were collected from 331 patients with sarcoma, while the imaging results and the variation in 1,25(OH)2D3 among 213 patients with sarcoma before and after treatment was further analyzed.

RESULTS

We found that the serum 1,25(OH)2D3 level was predominantly decreased in patients with sarcoma, with a mean of 45.68 nmol/L. 1,25(OH)2D3 was significantly correlated with the gender and age of sarcoma patients, with more substantial reductions in women and younger patients. Among sarcoma patients, those with progressive disease exhibited a 7.08 nmol/L (-13.73%) decrease in serum 1,25(OH)2D3 levels compared to baseline, while patients with non-progressive disease showed a 1.11 nmol/L (+ 7.0%) increase.

CONCLUSION

The variation of serum 1,25(OH)2D3 can predict the disease status of patients with sarcoma. Decreased serum 1,25(OH)2D3 levels are indicative of disease progression in sarcoma patients, suggesting its potential for application as a prognostic marker for disease assessment in this patient population.

Vitamin D Influences the Activity of Mast Cells in Allergic Manifestations and Potentiates Their Effector Functions against Pathogens

Mast cells (MCs) are abundant at sites exposed to the external environment and pathogens. Local activation of these cells, either directly via pathogen recognition or indirectly via interaction with other activated immune cells and results in the release of pre-stored mediators in MC granules. The release of these pre-stored mediators helps to enhance pathogen clearance. While MCs are well known for their protective role against parasites, there is also significant evidence in the literature demonstrating their ability to respond to viral, bacterial, and fungal infections. Vitamin D is a fat-soluble vitamin and hormone that plays a vital role in regulating calcium and phosphorus metabolism to maintain skeletal homeostasis. Emerging evidence suggests that vitamin D also has immunomodulatory properties on both the innate and adaptive immune systems, making it a critical regulator of immune homeostasis. Vitamin D binds to its receptor, called the vitamin D receptor (VDR), which is present in almost all immune system cells. The literature suggests that a vitamin D deficiency can activate MCs, and vitamin D is necessary for MC stabilization. This manuscript explores the potential of vitamin D to regulate MC activity and combat pathogens, with a focus on its ability to fight viruses.

Vitamin D Deficiency or Supplementation and the Risk of Human Herpesvirus Infections or Reactivation: A Systematic Review and Meta-analysis

BACKGROUND

Vitamin D may protect against respiratory virus infections, but any association with herpesviruses is unclear.

METHODS

We undertook a systematic review of vitamin D deficiency or supplementation and the risk of 8 human herpesviruses. Six databases and 4 gray literature databases were searched for relevant cohort studies, case-control studies, and clinical trials.

RESULTS

Ten studies were included, all conducted among immunosuppressed patients. There was no evidence that vitamin D deficiency is associated with cytomegalovirus (CMV) disease (pooled risk ratio, 1.06; 95% CI, 0.66-1.7), herpes zoster after transplantation (1 study), or HHV-8 among HIV patients (1 study). Vitamin D supplementation may decrease herpes zoster among hemodialysis patients (1 study) or CMV disease after renal transplantation (1 study), but supplementation was not associated with reduced EBV viral load among multiple sclerosis patients (1 study).

CONCLUSIONS

Any association between vitamin D and herpesviruses remains inconclusive. Further studies in the general population are needed.

Controversial Effects of Vitamin D and Related Genes on Viral Infections, Pathogenesis, and Treatment Outcomes

Vitamin D (VD) plays an essential role in mineral homeostasis and bone remodeling. A number of different VD-related genes (VDRG) are required for the metabolic activation of VD and the subsequent induction of its target genes. They include a set of genes that encode for VD-binding protein, metabolic enzymes, and the VD receptor. In addition to its well-characterized skeletal function, the immunoregulatory activities of VD and the related polymorphisms of VDRG have been reported and linked to its therapeutic and preventive actions for the control of several viral diseases. However, in regards to their roles in the progression of viral diseases, inconsistent and, in some cases, contradictory results also exist. To resolve this discrepancy, I conducted an extensive literature search by using relevant keywords on the PubMed website. Based on the volume of hit papers related to a certain viral infection, I summarized and compared the effects of VD and VDRG polymorphism on the infection, pathogenesis, and treatment outcomes of clinically important viral diseases. They include viral hepatitis, respiratory viral infections, acquired immunodeficiency syndrome (AIDS), and other viral diseases, which are caused by herpesviruses, dengue virus, rotavirus, and human papillomavirus. This review will provide the most current information on the nutritional and clinical utilization of VD and VDRG in the management of the key viral diseases. This information should be valuable not only to nutritionists but also to clinicians who wish to provide evidence-based recommendations on the use of VD to virally infected patients.

Association of Low Vitamin D with Complications of HIV and AIDS: A literature Review

With the advent of combination antiretroviral therapy (cART), the survival of HIV patients has improved dramatically, but the complications of the disease and treatment have become an important issue in the management of HIV patients. Vitamin-D deficiency is common in HIV patients. Low vitamin-D is associated with different comorbidities in the HIV uninfected general population. In this review, we first briefly describe vitamin D synthesis and mechanism of action and we focus on the epidemiological and clinical data dealing with the relationship between vitamin D deficiency in HIV infection with several comorbidities which has been found to be increasingly common in patients living with HIV infection. We searched the PubMed database using the keywords "HIV," "vitamin D" and other common disorders or conditions that are relatively common in HIV infection. The other conditions included in the search were osteoporosis and fracture, cardiovascular disease, diabetes and insulin resistance, active tuberculosis, hepatitis-C co-infection, and HIV disease progression. Articles presenting original data as well as systematic reviews and met analysis related to HIV population were included in our analysis. Vitamin-D deficiency seems to be associated with several adverse outcomes in HIV patients but a definite cause and effect relationship with vitamin-D is yet to be confirmed in most of the cases. However, the literature supporting the efficacy of vitamin-D supplementation is lacking.

Maternal plasma vitamin D levels and associated determinants in late pregnancy in Harare, Zimbabwe: a cross-sectional study

BACKGROUND

The importance of vitamin D in bone health and calcium homeostasis has been well documented. However, emerging evidence supports the role of vitamin D beyond its recognised traditional roles. In pregnancy, vitamin D levels are crucial in sustaining both the maternal stores and optimal growth of the foetus. In Southern Africa, there is paucity of data on vitamin D in pregnancy and related outcomes. To expand this body of knowledge, we assessed vitamin D levels in late pregnancy and (if any) associated maternal determinants in Harare, Zimbabwe.

METHODS

Study participants comprised of 138 pregnant Zimbabwean women in their third trimester. These were stratified by HIV status; sampling median (IQR) gestation for HIV negative study participants was 34 weeks (26-41) and 31 weeks (20-40) in the HIV positive participants. Maternal plasma 25 hydroxyvitamin (OH) Dlevels were measured using the ClinPrepHigh Pressure Liquid Chromatography (HPLC) kit. Statistical analysis was carried out using the STATA statistical package version 13. A p-value of < 0.05was considered to be statistically significant.

RESULTS

HIV infected participants had significantly higher mean 25 (OH) D concentration (112 ± 33.4 nmol/L) compared to the HIV uninfected (100 ± 27.1 nmol/L), p = 0.032.Participants whose samples were collected during summer had higher maternal 25 (OH) D levels than those cART duration and maternal 25 (OH) D levels (p = 0.031, Spearman correlation =0.28).

CONCLUSIONS

Our findings show high mean levels of maternal 25 (OH) D in late pregnancy in our setting and in the absence of vitamin D supplementation. Both HIV infection and season are significant determinants of maternal vitamin D levels. Summer season is associated with higher maternal plasma 25 (OH) D levels. HIV infection is associated with increased maternal vitamin D levels. Prolonged use of cART, Tenolam E is associated with improved maternal 25(OH) D levels.

Daily Nutritional Supplementation with Vitamin D₃ and Phenylbutyrate to Treatment-Naïve HIV Patients Tested in a Randomized Placebo-Controlled Trial

Poor nutritional status is common among human immunodeficiency virus (HIV)-infected patients including vitamin D (vitD₃) deficiency. We conducted a double-blinded, randomized, and placebo-controlled trial in Addis Ababa, Ethiopia, to investigate if daily nutritional supplementation with vitD₃ (5000 IU) and phenylbutyrate (PBA, 2 × 500 mg) could mediate beneficial effects in treatment-naïve HIV patients. Primary endpoint: the change in plasma HIV-1 comparing week 0 to 16 using modified intention-to-treat (mITT, n = 197) and per-protocol (n = 173) analyses. Secondary endpoints: longitudinal HIV viral load, T cell counts, body mass index (BMI), middle-upper-arm circumference (MUAC), and 25(OH)D₃ levels in plasma. Baseline characteristics were detectable viral loads (median 7897 copies/mL), low CD4⁺ (median 410 cells/µL), and elevated CD8⁺ (median 930 cells/µL) T cell counts. Most subjects were vitD₃ deficient at enrolment, but a gradual and significant improvement of vitD₃ status was demonstrated in the vitD₃ + PBA group compared with placebo (p < 0.0001) from week 0 to 16 (median 37.5 versus 115.5 nmol/L). No significant changes in HIV viral load, CD4⁺ or CD8⁺ T cell counts, BMI or MUAC could be detected. Clinical adverse events were similar in both groups. Daily vitD₃ + PBA for 16 weeks was well-tolerated and effectively improved vitD₃ status but did not reduce viral load, restore peripheral T cell counts or improve BMI or MUAC in HIV patients with slow progressive disease. Clinicaltrials.gov NCT01702974.

The interplay between vitamin D and viral infections

The pleiotropic role of vitamin D has been explored over the past decades and there is compelling evidence for an epidemiological association between poor vitamin D status and a variety of diseases. While the potential anti-viral effect of vitamin D has recently been described, the underlying mechanisms by which vitamin D deficiency could contribute to viral disease development remain poorly understood. The possible interactions between viral infections and vitamin D appear to be more complex than previously thought. Recent findings indicate a complex interplay between viral infections and vitamin D, including the induction of anti-viral state, functional immunoregulatory features, interaction with cellular and viral factors, induction of autophagy and apoptosis, and genetic and epigenetic alterations. While crosstalk between vitamin D and intracellular signalling pathways may provide an essential modulatory effect on viral gene transcription, the immunomodulatory effect of vitamin D on viral infections appears to be transient. The interplay between viral infections and vitamin D remains an intriguing concept, and the global imprint that vitamin D can have on the immune signature in the context of viral infections is an area of growing interest.

Vitamin D Deficiency in HIV Infection: Not Only a Bone Disorder

Hypovitaminosis D is a worldwide disorder, with a high prevalence in the general population of both Western and developing countries. In HIV patients, several studies have linked vitamin D status with bone disease, neurocognitive impairment, depression, cardiovascular disease, high blood pressure, metabolic syndrome, type 2 diabetes mellitus, infections, autoimmune diseases like type 1 diabetes mellitus, and cancer. In this review, we focus on the most recent epidemiological and experimental data dealing with the relationship between vitamin D deficiency and HIV infection. We analysed the extent of the problem, pathogenic mechanisms, clinical implications, and potential benefits of vitamin D supplementation in HIV-infected subjects.