Vitamin D: a pleiotropic hormone

Vitamin D-related genetic variants and prostate cancer risk in Black men

BACKGROUND

The relationship between vitamin D and prostate cancer has primarily been characterized among White men. Black men, however, have higher prostate cancer incidence and mortality rates, chronically low circulating vitamin D levels, and ancestry-specific genetic variants in vitamin D-related genes. Here, we examine critical genes in the vitamin D pathway and prostate cancer risk in Black men.

METHODS

We assessed a total of 73 candidate variants in genes (namely GC, CYP27A1, CYP27B1, CYP24A1, VDR, and RXRA) including functional variants previously associated with prostate cancer and circulating 25(OHD) in White men. Associations with prostate cancer risk were examined using genome-wide association study data for approximately 10,000 prostate cancer cases and 10,000 controls among Black men and over 85,000 cases and 91,000 controls among White men for comparison. A statistical significance threshold of 0.000685 was used to account for the 73 variants tested.

RESULTS

None of the variants examined were significantly associated with prostate cancer risk among Black men after multiple comparison adjustment. Suggestive associations (P < 0.05) for four variants were found in Black men, including two in RXRA (rs41400444 OR=1.09, 95 % CI: 1.01-1.17, P = 0.024 and rs10881574 OR = 0.93, 0.87-1.00, P = 0.046) and two in VDR (rs2853563 OR = 1.07, 1.01-1.13, P = 0.017 and rs1156882 OR = 1.06, 1.00-1.12, P = 0.045). Two variants in VDR were also positively associated with risk in White men (rs11568820 OR = 1.04, 1.02-1.06, P = 0.00024 and rs4516035 OR = 1.03, 1.01-1.04, P = 0.00055).

CONCLUSION

We observed suggestive associations between genetic variants in RXRA and VDR and prostate cancer risk in Black men. Future research exploring the relationship of vitamin D with cancer risk in Black men will need larger sample sizes to identify ancestry-specific variants relevant to risk in this population.

Vitamin D Supplementation Improves Pathological Complete Response in Breast Cancer Patients Undergoing Neoadjuvant Chemotherapy: A Randomized Clinical Trial

This study aimed to evaluate the effect of vitamin D (VD) supplementation on the pathological complete response (pCR) rate in women with breast cancer (BC) undergoing neoadjuvant chemotherapy (NCT). A randomized clinical trial was conducted with 80 women aged ≥45years with BC who were eligible for NCT. Women were randomized into two groups: VD group, daily supplementation with 2,000IU of cholecalciferol (n = 40) or placebo (n = 40), for 6 months. The primary outcome measure was the pCR rate. Serum 25-hydroxyvitamin-D [25(OH)D] levels were measured after BC diagnosis and the end of NCT. Of the 80 randomized women, 75 completed the NCT and underwent surgery. Baseline 25(OH)D values indicated hypovitaminosis D in both groups (VD: 19.6 ± 5.8 ng/mL and placebo: 21 ± 7.9 ng/mL, p = 0.33). After 6 months, 25(OH)D levels increased in the VD group compared to the placebo group (28 ± 8.7 vs. 20.2 ± 6.1 ng/mL, p = 0.03). The pCR rate was higher in women supplemented with VD when compared than the placebo (43% vs. 24%, p = 0.04). Adjusted logistic regression showed that women with 25(OH)D levels ≥20ng/mL were more likely to achieve pCR (OR3.65, 95%CI 1.09-12.8, p = 0.04). Women with BC undergoing NCT who received supplementation with 2,000IU of VD were more likely to achieve a pathological complete response than women in the placebo group.

TRIAL REGISTRATION

Ensaiosclinicos.gov.br, identifier RBR-10k4gqdg.

Vitamin D stimulates Il-15 synthesis in rodent muscle

Besides its classical skeletal function, vitamin D plays a critical role in both skeletal muscle and the immune system. Interleukin-15 (IL-15), which is highly expressed, and secreted complexed with its receptor, IL-15Rα, by skeletal muscle, stimulates the development of immune cells and affects myogenesis and muscle mass. However, little is known about possible regulators of this myokine. To test whether vitamin D could be a regulator of muscle IL-15 and IL-15Rα expression, C2C12 myotubes were treated with vitamin D3 metabolites and analysis were performed in gastrocnemius muscles of rats treated with a single intraperitoneal dose of 1,25(OH)2D3. The role of VDR was investigated by siRNA technique in C2C12 myotubes and in gastrocnemius muscles of vitamin D receptor knockout (Vdr-KO) mice. Treatment of C2C12 myotubes with 1,25(OH)2D3 or 25(OH)D3 increased Il-15 gene expression in a dose-dependent manner and 1,25(OH)2D3 also moderately increased the relative Il-15 protein amount. Rats treated with a single dose of 1,25(OH)2D3 demonstrated a higher mRNA abundance of muscle Il-15 than controls. The 1,25(OH)2D3 effect on Il-15 was considerably weaker in C2C12 myotubes treated with Vdr-specific siRNA. Vdr-KO mice showed significantly lower muscle Il-15 mRNA than WT mice. Il-15Ra mRNA and Il-15/Il-15Rα protein abundance were unaffected by 1,25(OH)2D3-treatment or VDR functionality, and Cyp27b1 activity is not required for 25(OH)D3-mediated Il-15 gene expression. The results provide evidence for a regulatory role of hydroxyvitamin D3 metabolites on the Il-15 synthesis in skeletal muscle cells, which is largely mediated by the VDR.

Vitamin D Deficiency Meets Hill's Criteria for Causation in SARS-CoV-2 Susceptibility, Complications, and Mortality: A Systematic Review

Clinical trials consistently demonstrate an inverse correlation between serum 25-hydroxyvitamin D [25(OH)D; calcifediol] levels and the risk of symptomatic SARS-CoV-2 disease, complications, and mortality. This systematic review (SR), guided by Bradford Hill's causality criteria, analyzed 294 peer-reviewed manuscripts published between December 2019 and November 2024, focusing on plausibility, consistency, and biological gradient. Evidence confirms that cholecalciferol (D3) and calcifediol significantly reduce symptomatic disease, complications, hospitalizations, and mortality, with optimal effects above 50 ng/mL. While vitamin D requires 3-4 days to act, calcifediol shows effects within 24 h. Among 329 trials, only 11 (3%) showed no benefit due to flawed designs. At USD 2/patient, D3 supplementation is far cheaper than hospitalization costs and more effective than standard interventions. This SR establishes a strong inverse relationship between 25(OH)D levels and SARS-CoV-2 vulnerability, meeting Hill's criteria. Vitamin D3 and calcifediol reduce infections, complications, hospitalizations, and deaths by ~50%, outperforming all patented, FDA-approved COVID-19 therapies. With over 300 trials confirming these findings, waiting for further studies is unnecessary before incorporating them into clinical protocols. Health agencies and scientific societies must recognize the significance of these results and incorporate D3 and calcifediol for prophylaxis and early treatment protocols of SARS-CoV-2 and similar viral infections. Promoting safe sun exposure and adequate vitamin D3 supplementation within communities to maintain 25(OH)D levels above 40 ng/mL (therapeutic range: 40-80 ng/mL) strengthens immune systems, reduces hospitalizations and deaths, and significantly lowers healthcare costs. When serum 25(OH)D levels exceed 70 ng/mL, taking vitamin K2 (100 µg/day or 800 µg/week) alongside vitamin D helps direct any excess calcium to bones. The recommended vitamin D dosage (approximately 70 IU/kg of body weight for a non-obese adult) to maintain 25(OH)D levels between 50-100 ng/mL is safe and cost-effective for disease prevention, ensuring optimal health outcomes.

A Novel Organophosphate Ester, Tris(2,4-ditert-butylphenyl) Phosphate, Induced Reproductive Toxicity in Male Zebrafish at Environmentally Relevant Concentrations

As a novel organophosphate ester (NOPE), tris(2,4-ditert-butylphenyl) phosphate (TDtBPP) has attracted significant attention due to its unexpectedly high detection in natural environments. However, the ecological toxic effects of environmentally relevant concentrations of TDtBPP in organisms remain entirely unknown. In this study, 1 month old zebrafish were exposed to 0, 50, 500, or 5000 ng/L TDtBPP for 150 days, and the reproductive toxicity in male fish was evaluated. Results demonstrated that TDtBPP exposure significantly inhibited the maturation of spermatozoa and thus decreased spermatogenesis. Furthermore, abnormal sperm morphology and decreased sperm motility were also observed. The decrease in sperm quantity and quality eventually resulted in the declining fecundity. Moreover, TDtBPP exposure downregulated the expression of hsd3b1 in vivo and in vitro and subsequently inhibited the synthesis of androgens in zebrafish testes and Leydig cells. This inhibition of androgen synthesis appeared to be responsible for the observed reproductive toxicity in male fish. Molecular docking and dual-luciferase reporter gene experiments elucidated that TDtBPP inhibited the promotion of vitamin D on hsd3b1 transcription by the vitamin D receptor and thus downregulated the expression of hsd3b1. Our findings provide first time evidence that TDtBPP poses a risk to male fish reproduction at environmentally relevant levels.

The relationships of serum vitamin D concentration with linear speed and change of direction performance in soccer players

The aim of the study was to establish whether the level of 25 hydroxyvitamin D (25(OH)D) in serum has an influence on speed (m/s) and change of direction (COD, s) performance. Twenty male soccer players from the top league participated in the study. All subjects were evaluated for the serum concentration of 25(OH)D at the beginning of the preseason. The linear sprint test was performed at 5 m and 30 m, and COD (time and deficit) at the beginning (BPP) and after (APP) 6 weeks of the preparatory period. The results revealed that 20% of soccer players had a significant deficiency of 25(OH)D (<20 ng/mL) and 30% had insufficient 25(OH)D levels (between 20 and 30 ng/mL). Positive correlations were found between the training effect for the ∆COD (BPP-APP) (p = 0.003) and ∆deficit (BPP-APP) (p = 0.039). Significant differences were noticed for the ∆COD (m = 0.60 [s]) and ∆deficit (m = 0.56[s]) in the soccer players whose 25(OH)D concentration was <=30 ng/mL, and for the ∆COD (p = 0.002) and ∆deficit (p = 0.017) in the soccer players whose 25(OH)D concentration was >30 ng/mL. The training effect was significantly higher for the soccer players whose 25(OH)D concentration was above 30 ng/mL. Soccer players with higher 25(OH)D levels achieved superior results in the COD test and demonstrated better deficit outcomes, affirming the positive influence of 25(OH)D on muscle metabolism.

Sodium-glucose cotransporter 2 inhibitors and renin-angiotensin-aldosterone system, possible cellular interactions and benefits

Sodium glucose cotransporter 2 inhibitors (SGLT2is) are a newly developed class of anti-diabetics which exert potent hypoglycemic effects in the diabetic milieu. However, the evidence suggests that they also have extra-glycemic effects. The renin-angiotensin-aldosterone system (RAAS) is a hormonal system widely distributed in the body that is important for water and electrolyte homeostasis as well as renal and cardiovascular function. Therefore, modulating RAAS activity is a main goal in patients, notably diabetic patients, which are at higher risk of complications involving these organ systems. Some studies have suggested that SGLT2is have modulatory effects on RAAS activity in addition to their hypoglycemic effects and, thus, these drugs can be considered as promising therapeutic agents for renal and cardiovascular disorders. However, the exact molecular interactions between SGLT2 inhibition and RAAS activity are not clearly understood. Therefore, in the current study we surveyed the literature for possible molecular mechanisms by which SGLT2is modulate RAAS activity.

A 12-week double-blind randomised controlled trial investigating the effect of dietary supplementation with 125 μg/d vitamin D in adults with asthma

Vitamin D deficiency has previously been linked to higher rates of exacerbation and reduced lung function in asthmatics. Previous randomised controlled trials investigating the effect of vitamin D supplementation have mainly focused on children with asthma. Trials involving adults have typically used bolus dosing regimens, and the main outcomes have been patient-focused without investigating underlying inflammation. The present study aimed to conduct a 12-week placebo-controlled randomised controlled trials administering a daily 125 µg vitamin D3 supplement to adults with mild to moderate asthma. A total of 32 participants were randomised to receive either the 125 μg vitamin D3 supplement or an identical matching placebo. The primary outcome of the study was lung function measured by the ratio of FEV1:FVC (effect size 2·5) with secondary outcomes including asthma symptoms and inflammatory biomarkers. There was a small but statistically significant higher increase in the mean (±sd) ratio of FEV1:FVC from baseline to post-intervention in the vitamin D group (+0·05 ± 0·06) compared with the placebo group (+0·006 ± 0·04, P = 0·04). There was no effect of the intervention on asthma control test scores, or the inflammatory biomarkers measured. There was a moderate, significant association between baseline plasma 25(OH)D concentration and baseline plasma IL-10 (r = 0·527, P = 0·005) and TNF-α (r = −0·498. P = 0·008) concentrations. A daily vitamin D3 supplement led to slightly improved lung function in adult asthmatics and may be a useful adjunct to existing asthma control strategies, particularly for individuals with suboptimal vitamin D status.

Plasma vitamin D levels are correlated with the pathogenesis of human T-cell leukemia virus type 1-associated diseases

The active form of vitamin D (VD) exerts hormonal effects by regulating the expression of genes involved in T-cell activity, cell differentiation, and proliferation. Human T-cell leukemia virus type 1 (HTLV-1) is a causative agent of life-threatening diseases, adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy (HAM). Among ATL patients, hypercalcemia is one of the most serious complications due to bone resorption. In this study, wild-type mice administered UV-irradiated HTLV-1-infected cells showed up to 47% decrease of plasma VD level compared with untreated mice. To clarify the effect of HTLV-1 on plasma VD level, 315 samples registered in nationwide cohort study on ATL onset were measured. The VD level in HAM (14.98 ± 8.5 ng/mL) was significantly lower than those in asymptomatic carriers and ATL (p < 0.05). Upon comparing the VD levels in ATL stratified by disease subtypes, acute ATL showed a lower level (15.81 ± 12.0 ng/mL) than chronic and smoldering types (p < 0.05). In the longitudinal observation, VD levels were significantly higher in untreated spontaneous remission cases than in ATL progression cases, in which the VD levels decreased approximately 40% after onset. In cases of relapse after transplantation, the plasma VD level dropped to 38.7% of the pre-relapse level, while in cases of complete remission, the VD level increased with improvement of the performance status. Taken together, these results suggest that plasma VD level is a potential indicator for the onset and relapse of HTLV-1-associated diseases.

Antioxidant Functions of Vitamin D and CYP11A1-Derived Vitamin D, Tachysterol, and Lumisterol Metabolites: Mechanisms, Clinical Implications, and Future Directions

Evidence is increasing that vitamin D and CYP11A1-derived vitamin D, tachysterol, and lumisterol metabolites play a significant antioxidant role beyond its classical functions in bone health and calcium metabolism. Several recent studies have linked these elements to reduced oxidative stress as well as improved immune, cardiovascular, and neurological functions as a result of chronic kidney disease and cancer. Additionally, supplementation with this vitamin has been shown to be one of the most cost-effective micronutrient interventions worldwide, highlighting its potential as a therapeutic approach. The underlying mechanisms and implications of this antioxidant function of vitamin D or CYP11A1-derived vitamin D, tachysterol, and lumisterol metabolites are not well understood. This comprehensive and narrative review is aimed at summarizing the current evidence regarding the molecular mechanisms implicated in this antioxidant function of vitamin D, as well as to provide a general overview and to identify key research areas for the future, offering an extensive perspective that can guide both researchers and clinicians in the management of diseases associated with oxidative stress and/or insufficient vitamin D status.

Variants in Vitamin D-related Genes and Prostate Cancer Risk in Black Men

BACKGROUND

The relationship between vitamin D and prostate cancer has primarily been characterized among White men. However, Black men have higher prostate cancer incidence and mortality rates, chronically low circulating vitamin D levels, and ancestry-specific genetic variants in vitamin D-related genes. Here, we examine six critical genes in the vitamin D pathway and prostate cancer risk in Black men.

METHODS

We assessed a total of 69 candidate variants in six genes ( GC, CYP27A1, CYP27B1, CYP24A1, VDR , and RXRA ) including functional variants previously associated with prostate cancer and circulating 25(OHD) in White men. Associations with prostate cancer risk were examined using genome-wide association study data for approximately 10,000 prostate cancer cases and 10,000 controls among Black men and over 85,000 cases and 91,000 controls among White men. A statistical significance threshold of 0.000724 was used to account for the 69 variants tested.

RESULTS

None of the variants examined were significantly associated with prostate cancer risk among Black men after multiple comparison adjustment. Four variants tested P<0.05 in Black men, including two in RXRA (rs41400444 OR=1.09, 95% CI: 1.01-1.17, P = 0.024 and rs10881574 OR = 0.93, 0.87-1.00, P = 0.046) and two in VDR (rs2853563 OR = 1.07, 1.01-1.13, P = 0.017 and rs1156882 OR = 1.06, 1.00-1.12, P = 0.045). Two variants in VDR were also positively associated with risk in White men (rs11568820 OR = 1.04, 1.02-1.06, P = 0.00024 and rs4516035 OR = 1.03, 1.01-1.04, P = 0.00055).

CONCLUSION

We observed suggestive non-significant associations between genetic variants in RXRA and VDR and prostate cancer risk in Black men. Future research exploring the relationship of vitamin D with cancer risk in Black men will need larger sample sizes to identify ancestry-specific variants relevant to risk in this population.

Organic phosphate but not inorganic phosphate regulates Fgf23 expression through MAPK and TGF-ꞵ signaling

One of the main regulators of phosphate homeostasis is fibroblast growth factor 23 (FGF23), secreted by osteocytes. The effects of organic versus inorganic dietary phosphate on this homeostasis are unclear. This study used MC3T3-E1 FGF23-producing cells to examine the transcriptomic responses to these phosphates. Most importantly, the expression and secretion of FGF23 were only increased in response to organic phosphate. Gene ontology terms related to a response to environmental change were only enriched in cells treated with organic phosphate while cells treated with inorganic phosphate were enriched for terms associated with regulation of cellular phosphate metabolism. Inhibition of MAPK signaling diminished the response of Fgf23 to organic phosphate, suggesting it activates FGF23. TGF-β signaling inhibition increased Fgf23 expression after the addition of organic phosphate, while the negative TGF-β regulator Skil decreased this response. In summary, the observed differential response of FGF23-producing to phosphate types may have consequences for phosphate homeostasis.

Current Aspects of Selected Factors to Modulate Brain Health and Sports Performance in Athletes

This review offers a comprehensive evaluation of current aspects related to nutritional strategies, brain modulation, and muscle recovery, focusing on their applications and the underlying mechanisms of physiological adaptation for promoting a healthy brain, not only in athletes but also for recreationally active and inactive individuals. We propose that applying the rule, among others, of good sleep, regular exercise, and a properly balanced diet, defined as "SPARKS", will have a beneficial effect on the function and regeneration processes of the gut-brain-muscle axis. However, adopting the formula, among others, of poor sleep, stress, overtraining, and dysbiosis, defined as "SMOULDER", will have a detrimental impact on the function of this axis and consequently on human health as well as on athletes. Understanding these dynamics is crucial for optimizing brain health and cognitive function. This review highlights the significance of these factors for overall well-being, suggesting that adopting the "SPARKS" approach may benefit not only athletes but also older adults and individuals with health conditions.

Association Between Vitamin D Deficiency and Tumor Characteristics in Breast Cancer Patients

Introduction Breast cancer is the most frequent cancer among women worldwide, but there is little literature regarding the effects of vitamin D on breast cancer patients in the Indian population. Hence, this study was planned to determine the correlation between vitamin D deficiency and tumor characteristics in breast cancer patients. Methods This was a cross-sectional study conducted in a tertiary healthcare facility in central India among all newly diagnosed patients with breast carcinoma who had received primary surgery and pathological confirmation. We performed universal sampling and included 50 patients in the study. We excluded patients with insufficient histopathological reports, those unfit for surgery, and those with hepatic or renal failure, metabolic bone disease, malabsorption, or recent consumption of vitamin D (patients who had received oral vitamin D in the preceding two weeks, or vitamin D injection in the preceding six months). Results Among the 50 patients, 86% were vitamin D deficient, with a mean deficiency of 23.54. Vitamin D deficiency is most common in the age groups 41-50 years and >60 years, with the mean age group of 51.49 years. The left side is more involved than the right in vitamin D-deficient patients. Most patients were moderately and poorly differentiated, suggesting a significant association between vitamin D deficiency and tumor differentiation. Almost half the patients were estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (Her-2/neu) status negative with vitamin D deficiency. Vitamin D deficiency was highest in Her-2/neu amplified, luminal A, and B patients. The mean lymph node-positive participants was 4.04, and the mean number of lymph nodes extracted was 15.58 in vitamin D-deficient breast cancer patients. Conclusion The prevalence of low vitamin D status was high among breast cancer patients. There is an association between vitamin D deficiency and tumors with poor prognostic features. Low vitamin D levels were considered a risk factor for ER, PR, and Her-2/neu-negative tumors along with positive lymph node status in breast cancer patients. Vitamin D status is a modifiable risk factor for breast cancer. Thus, it is concluded from this study that vitamin D has a potential role in the prevention of breast cancer, it may reduce its aggressiveness, and its deficiency is associated with an increased risk of breast cancer.

Design, synthesis, and biological activity of D-bishomo-1α,25-dihydroxyvitamin D3 analogs and their crystal structures with the vitamin D nuclear receptor

The biologically active metabolite of vitamin D3 - calcitriol - is a hormone involved in the regulation of calcium-phosphate homeostasis, immunological processes and cell differentiation, being therefore essential for the proper functioning of the human body. This suggests many applications of this steroid in the treatment of diseases such as rickets, psoriasis and some cancers. Unfortunately, using therapeutic doses of calcitriol is associated with high concentrations of this compound which causes hypercalcemia. For this reason, new calcitriol analogs are constantly sought, devoid of calcemic effects but maintaining its beneficial properties. In this study, we present the synthesis of vitamin D derivatives characterized by an enlarged (seven-membered) ring D. Preparation of the designed vitamin D compounds required separate syntheses of crucial building blocks (C/D-rings fragments with side chain and rings A) which were combined by different methods, including Wittig-Horner reaction and Suzuki coupling. Biological activities of the target vitamin D analogs were assessed both in vitro and in vivo, demonstrating their significant potency compared to the natural hormone. Furthermore, the successful crystallization of these compounds with the vitamin D receptor (VDR) enabled us to investigate additional molecular interactions with this protein.

Enhanced Metabolic Effects of Fish Oil When Combined with Vitamin D in Diet-Induced Obese Male Mice

Vitamin D (vit D) and fish oil (FO) both offer unique health benefits, however, their combined effects have not been evaluated in obesity and nonalcoholic fatty liver disease (NAFLD). Hence, we hypothesized that vit D and FO supplementation would have additive effects in reducing obesity-associated inflammation and NAFLD. Male C57BL6 mice were split into four groups and fed a high fat (HF) diet supplemented with a low (HF; +200 IU vit D) or high dose of vitamin D (HF + D; +1000 IU vit D); combination of vit D and FO (HF-FO; +1000 IU vit D); or only FO (HF-FO; +200 IU vit D) for 12 weeks. We measured body weight, food intake, glucose tolerance, and harvested epididymal fat pad and liver for gene expression analyses. Adiposity was reduced in groups supplemented with both FO and vit D. Glucose clearance was higher in FO-supplemented groups compared to mice fed HF. In adipose tissue, markers of fatty acid synthesis and oxidation were comparable in groups that received vit D and FO individually in comparison to HF. However, the vit D and FO group had significantly lower fatty acid synthesis and higher oxidation compared to the other groups. Vit D and FO also significantly improved fatty acid oxidation, despite similar fatty acid synthesis among the four groups in liver. Even though we did not find additive effects of vit D and FO, our data provide evidence that FO reduces markers of obesity in the presence of adequate levels of vit D.

Oleanolic acid exerts bone anabolic effects via activation of osteoblastic 25-hydroxyvitamin D 1-alpha hydroxylase

Oleanolic acid (OA) is previously shown to exert bone protective effects in aged animals. However, its role in regulating osteoblastic vitamin D bioactivation, which is one of major causes of age-related bone loss, remains unclear. Our results revealed that treatment of OA significantly increased skeletal CYP27B1 expression and circulating 1,25(OH)2D3 in ovariectomized mice (p <0.01). Moreover, OA upregulated CYP27B1 protein expression and activity, as well as the vitamin D-responsive bone markers alkaline phosphatase (ALP) activity and osteopontin (OPN) protein expression, in human osteoblast-like MG-63 cells (p<0.05). CYP27B1 expression increased along with the osteoblastic differentiation of human bone marrow derived mesenchymal stem cells (hMSCs). CYP27B1 expression and cellular 1,25(OH)2D3 production were further potentiated by OA in cells at mature osteogenic stages. Notably, our study suggested that the osteogenic actions of OA were CYP27B1 dependent. In summary, the bone protective effects of OA were associated with the induction of CYP27B1 activity and expression in bone tissues and osteoblastic lineages. Hence, OA might be a potential approach for management of age-related bone loss.

The improvement of homocysteine-induced myocardial inflammation by vitamin D depends on activation of NFE2L2 mediated MTHFR

OBJECTIVES

Myocardial inflammation underlies a broad spectrum of conditions that cause damage to the myocardium and lead to structural and functional defects. Homocysteine (Hcy) is closely related to the occurrence and development of cardiovascular diseases. We investigated the mechanism underlying the effects of vitamin D as a prophylactic treatment for Hcy-induced cardiac inflammation.

METHODS

The levels of 25(OH)D3 and Hcy were assessed using ELISA kits. Expression levels of the vitamin D receptor (VDR), NFE2 like bZIP transcription factor 2 (NFE2L2), methylenetetrahydrofolate reductase (MTHFR) and inflammatory factors were examined by Western blotting, immunohistochemistry and real time polymerase chain reaction. NFE2L2/MTHFR-knockdown HL-1 cells and NFE2L2+/- mouse were used to test the effects of vitamin D.

RESULTS

We found the levels of Hcy in the serum and myocardial tissue of mice in the Hcy + CCE group were lower than in the Hcy groups, which was opposed to the trend exhibited by the serum 25(OH)D3 level of mice. The mRNA and protein expression levels of the inflammatory factors in cardiac tissues and cardiomyocytes were strongly decreased by the Hcy treatment, compared to the Hcy + CCE/Hcy + 1,25(OH)2D3 groups. Moreover, the results revealed that the level of nuclear NFE2L2 in Hcy + CCE/Hcy + 1,25(OH)2D3 group was increased compared to Hcy group with a reciprocal decrease in the level of cytosolic NFE2L2 in vivo and in vitro. Similarly, the MTHFR mRNA and protein expression in the Hcy + CCE group was higher than the Hcy group. We determined that NFE2L2 promoted the expression of MTHFR. However, based on Hcy treatment, the combination of 1,25(OH)2D3 and MTHFR-/- reversed the decline in IL-6 and TNFα expression caused by 1,25(OH)2D3 alone. Chromatin immunoprecipitation and luciferase reporter assays showed the up-regulation effect of VDR on NFE2L2 and NFE2L2 on MTHFR.

CONCLUSIONS

Our findings indicate that vitamin D/VDR could improve Hcy-induced myocardial inflammation through activation of NFE2L2 mediated MTHFR.

Vitamin D Status in Palindromic Rheumatism: A Propensity Score Matching Analysis

OBJECTIVE

To determine whether there is a correlation between vitamin D levels and palindromic rheumatism (PR) as an at-risk phenotype of rheumatoid arthritis (RA).

METHODS

A total of 308 participants were enrolled in this cross-sectional study. We recorded their clinical characteristics and performed propensity-score matching (PSM). Serum 25(OH)D3 levels were determined via enzyme-linked immunosorbent assay.

RESULTS

Our PSM resulted in 48 patients with PR and 96 matched control individuals. The multivariate regression analysis we performed after the PSM did not show a significant increase in PR risk in patients with vitamin D deficiency/insufficiency. There was no significant correlation between levels of 25(OH)D3 and frequency/duration of attacks, number of joints affected, and duration of symptoms before diagnosis (P ≥ .05). Mean (SD) serum levels of 25(OH)D3 in patients with and without progression to RA were 28.7 (15.9) ng/mL and 25.1 (11.4) ng/mL, respectively.

CONCLUSION

Based on the results, we found no clear association between vitamin D serum levels and the risk, severity, and rate of PR progressing into RA.

Evaluation of serum anti-Müllerian hormone concentrations following treatment with vitamin D in Holstein Friesian heifers

Anti-Müllerian hormone (AMH) levels in the blood of dairy cattle are associated with the count of antral follicles (AFC), ovarian function. Numerous studies, particularly in human medicine, have shown that vitamin D3 (Vit D3) has a positive effect on AMH levels. To our knowledge, the effects of Vit D3 on serum AMH levels in heifers have not been investigated. The goal of the current study was to evaluate the concentrations of serum AMH in dairy heifers following Vit D3 treatment. The study included 20 healthy non-pregnant Holstein Friesian heifers. These animals came to estrus at least once. All heifers received a single intramuscular dosage of 5 million IU Vit D3 (Cholecalciferol). Blood samples were collected from the coccygeal veins of all animals before and after Vit D3 injection (days 7, 14, and 28) for the measurement of AMH and 25(OH)D concentrations. In our analysis, we observed that after exogenous Vit D3 administration, circular 25(OH)D increased constantly (up to day 28 after Vit D3 injection) in all animals. On day 28, AMH concentrations saw a 10% increase in comparison with those measured the day before the Vit D3 injection. However, a comparison of AMH concentrations measured across days did not reveal statistically significant differences between Day 0, 7, 14, and 28 levels (p = .10). Furthermore, no statistical correlation was observed between the pairs (age-AMH) and (weight-AMH). Considering all times, no correlation was found between 25(OH)D and blood AMH levels. These findings demonstrated that exogenous Vit D3 did not affect serum AMH in Holstein Friesian heifers.

In vitro regulation of fibroblast growth factor 23 by 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D synthesized by osteocyte-like MC3T3-E1 cells

Fibroblast growth factor 23 (FGF23) is produced and secreted by osteocytes and is essential for maintaining phosphate homeostasis. One of the main regulators of FGF23, 1,25-dihydroxyvitamin D (1,25(OH)2D3), is primarily synthesized in the kidney from 25-hydroxyvitamin D (25(OH)D) by 1α-hydroxylase (encoded by CYP27B1). Hitherto, it is unclear whether osteocytes can convert 25(OH)D and thereby allow for 1,25(OH)2D3 to induce FGF23 production and secretion locally. Here, we differentiated MC3T3-E1 cells toward osteocyte-like cells expressing and secreting FGF23. Treatment with 10-6 M 25(OH)D resulted in conversion of 25(OH)D to 150 pmol/L 1,25(OH)2D3 and increased FGF23 expression and secretion, but the converted amount of 1,25(OH)2D3 was insufficient to trigger an FGF23 response, so the effect on FGF23 was most likely directly caused by 25(OH)D. Interestingly, combining phosphate with 25(OH)D resulted in a synergistic increase in FGF23 expression and secretion, likely due to activation of additional signaling pathways by phosphate. Blockage of the vitamin D receptor (VDR) only partially abolished the effects of 25(OH)D or 25(OH)D combined with phosphate on Fgf23, while completely inhibiting the upregulation of cytochrome P450 family 24 subfamily A member 1 (Cyp24a1), encoding for 24-hydroxylase. RNA sequencing and in silico analyses showed that this could potentially be mediated by the nuclear receptors Retinoic Acid Receptor β (RARB) and Estrogen Receptor 2 (ESR2). Taken together, we demonstrate that osteocytes are able to convert 25(OH)D to 1,25(OH)2D3, but this is insufficient for FGF23 activation, implicating a direct effect of 25(OH)D in the regulation of FGF23, which occurs at least partially independent from its cognate VDR. Moreover, phosphate and 25(OH)D synergistically increase expression and secretion of FGF23, which warrants investigating consequences in patients receiving a combination of vitamin D analogues and phosphate supplements. These observations help us to further understand the complex relations between phosphate, vitamin D, and FGF23.

Vitamin D3 analogue calcipotriol inhibits the profibrotic effects of transforming growth factor- β1 on pancreatic stellate cells

OBJECTIVE

To evaluate the inhibitory effect of vitamin D3 analogue calcipotriol (Cal) on the fibrosis of pancreatic stellate cells (PSCs) induced by TGF-β1 and the rationality of Cal use in alcoholic chronic pancreatitis (ACP).

MATERIAL AND METHODS

Double-labeling immunofluorescence was used for the identification of VDR+PSCs in the pancreas of healthy controls (HC) and ACP patients. Van Gieson staining for examination of collagen fibers. RT-qPCR and Western Blot for determining the mRNAs and proteins of VDR, TGF-β1 and COL1A1 in the pancreas of ACP or in vitro PSCs. ELISA or LC-MS/MS for detection of serum TGF-β1 and COL1A1 or 25(OH)D3. The PSC line (RP-2 cell) was used for the determination of proteomic alterations in Cal plus TGF-β1 versus TGF-β1 and to examine the effect of VDR gene knockdown.

RESULTS

Enhanced expression of VDR was detected in RP-2 cells stimulated with alcohol (ALC) plus Cal versus Cal alone and in PSCs in the pancreas of ACP versus HC. The increased VDR+PSCs were positively correlated with the levels of COL1A1 mRNAs or areas of collagen deposition in the pancreas of ACP. TGF-β1 was overexpressed in the pancreas of ACP and ALC-treated RP-2 cells while 25(OH)D3 level in serum was significantly decreased in ACP versus HC. Through a VDR-dependent mechanism, Cal antagonized 16 profibrotic proteins in TGF-β1-induced RP-2 cells that included 7 extracellular matrix components, 2 cytoskeletal proteins, 2 fibrosis-associated factors (RUNX1 and TRAF2), TIMP-1, CCN1, integrin α11, an adhesion scaffold protein (TGFB1i1) and an enzyme mediating TGF-β1-induced fibrogenesis (ENPP1).

CONCLUSION

This study suggests that Cal administration may be a potential antifibrotic strategy via inhibiting TGF-β1-mediated PSC action during the development of ACP.

Linking Mechanisms of Vitamin D Signaling with Multiple Sclerosis

Environmental triggers often work via signal transduction cascades that modulate the epigenome and transcriptome of cell types involved in the disease process. Multiple sclerosis (MS) is an autoimmune disease affecting the central nervous system being characterized by a combination of recurring inflammation, demyelination and progressive loss of axons. The mechanisms of MS onset are not fully understood and genetic variants may explain only some 20% of the disease susceptibility. From the environmental factors being involved in disease development low vitamin D levels have been shown to significantly contribute to MS susceptibility. The pro-hormone vitamin D3 acts via its metabolite 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) as a high affinity ligand to the transcription factor VDR (vitamin D receptor) and is a potent modulator of the epigenome at thousands of genomic regions and the transcriptome of hundreds of genes. A major target tissue of the effects of 1,25(OH)2D3 and VDR are cells of innate and adaptive immunity, such as monocytes, dendritic cells as well as B and T cells. Vitamin D induces immunological tolerance in T cells and reduces inflammatory reactions of various types of immune cells, all of which are implicated in MS pathogenesis. The immunomodulatory effects of 1,25(OH)2D3 contribute to the prevention of MS. However, the strength of the responses to vitamin D3 supplementation is highly variegated between individuals. This review will relate mechanisms of individual's vitamin D responsiveness to MS susceptibility and discuss the prospect of vitamin D3 supplementation as a way to extinguish the autoimmunity in MS.

Exploring the Effects of Vitamin D and Vitamin A Levels on the Response to COVID-19 Vaccine

COVID-19 vaccines were developed at an unprecedented speed in history. The factors affecting the response to COVID-19 vaccines are not clear. Herein, the effects of vitamin D and vitamin A (retinol) levels on the response to the BNT162b2 vaccine were explored. A total of 124 vaccine recipients were recruited from the general population attending vaccination centers in Irbid, Jordan. Blood samples were collected immediately before receiving the first vaccine dose (D0) and three weeks later (D21). Baseline (D0) levels of 25-hydroxyvitamin D [25(OH)D], retinol, and SARS-CoV-2 S1 IgG antibodies were measured with ELISA. The response to the BNT162b2 vaccine was tested by measuring the levels and avidity of SARS-CoV-2 S1 IgG antibodies on D21. The participants were divided into two groups, unexposed and exposed, based on the D0 SARS-CoV-2 antibody results. No significant correlation was found between the levels of 25(OH)D or retinol and the levels, avidity, or fold increase of antibodies in both groups. Similarly, no significant difference in antibody response was found between 25(OH)D status groups, retinol status groups, or combined status groups. These findings show that the baseline vitamin D or vitamin A levels have no effect on the short-term response to a single dose of BNT162b2 vaccine.

Infections and Autoimmunity-The Immune System and Vitamin D: A Systematic Review

Both 25-autoimmunity and(25(OH)D: calcifediol) and its active form, 1,25-dihydroxyvitamin D (1,25(OH)2D: calcitriol), play critical roles in protecting humans from invasive pathogens, reducing risks of autoimmunity, and maintaining health. Conversely, low 25(OH)D status increases susceptibility to infections and developing autoimmunity. This systematic review examines vitamin D's mechanisms and effects on enhancing innate and acquired immunity against microbes and preventing autoimmunity. The study evaluated the quality of evidence regarding biology, physiology, and aspects of human health on vitamin D related to infections and autoimmunity in peer-reviewed journal articles published in English. The search and analyses followed PRISMA guidelines. Data strongly suggested that maintaining serum 25(OH)D concentrations of more than 50 ng/mL is associated with significant risk reduction from viral and bacterial infections, sepsis, and autoimmunity. Most adequately powered, well-designed, randomized controlled trials with sufficient duration supported substantial benefits of vitamin D. Virtually all studies that failed to conclude benefits or were ambiguous had major study design errors. Treatment of vitamin D deficiency costs less than 0.01% of the cost of investigation of worsening comorbidities associated with hypovitaminosis D. Despite cost-benefits, the prevalence of vitamin D deficiency remains high worldwide. This was clear among those who died from COVID-19 in 2020/21-most had severe vitamin D deficiency. Yet, the lack of direction from health agencies and insurance companies on using vitamin D as an adjunct therapy is astonishing. Data confirmed that keeping an individual's serum 25(OH)D concentrations above 50 ng/mL (125 nmol/L) (and above 40 ng/mL in the population) reduces risks from community outbreaks, sepsis, and autoimmune disorders. Maintaining such concentrations in 97.5% of people is achievable through daily safe sun exposure (except in countries far from the equator during winter) or taking between 5000 and 8000 IU vitamin D supplements daily (average dose, for non-obese adults, ~70 to 90 IU/kg body weight). Those with gastrointestinal malabsorption, obesity, or on medications that increase the catabolism of vitamin D and a few other specific disorders require much higher intake. This systematic review evaluates non-classical actions of vitamin D, with particular emphasis on infection and autoimmunity related to the immune system.

Dietary and Serum Antioxidants Associated with Prostate-Specific Antigen for Middle-Aged and Older Men

High prostate-specific antigen (PSA) levels can indicate potential prostate problems and are a warning sign of prostate cancer. The impact of antioxidants on the PSA of generally healthy men is understudied. This study aims to evaluate 14 dietary and endogenous antioxidants associated with PSA levels for United States (US) men. We assessed 7398 men using the 2003-2010 US population-based National Health and Nutrition Examination Survey (NHANES). The PSA levels were categorized into three groups: Normal, borderline, and elevated levels. We performed analyses for middle-aged and older groups aged 40-64.9 and ≥65, respectively. The weighted multinomial regressions were performed to evaluate antioxidants associated with the PSA status. For results, 0.3% and 3.4% of middle-aged and older men, respectively, had elevated PSA (>10 ng/mL). Men with a higher serum albumin level had a lower risk of an elevated PSA, adjusting for age. The magnitude of albumin's impact on PSA is larger in middle-aged men than in older men (OR of elevated PSA = 0.82 and 0.90, respectively, interaction p = 0.002). Other antioxidants are not associated with PSA. Our findings support men with low serum albumin tend to have an elevated PSA level, so related interventions can be considered to decrease PSA for maintaining prostate health.

Enzymatic activation in vitamin D signaling - Past, present and future

Vitamin D signaling is important in regulating calcium homeostasis essential for bone health but also displays other functions in cells of several tissues. Disturbed vitamin D signaling is linked to a large number of diseases. The multiple cytochrome P450 (CYP) enzymes catalyzing the different hydroxylations in bioactivation of vitamin D₃ are crucial for vitamin D signaling and function. This review is focused on the progress achieved in identification of the bioactivating enzymes and their genes in production of 1α,25-dihydroxyvitamin D₃ and other active metabolites. Results obtained on species- and tissue-specific expression, catalytic reactions, substrate specificity, enzyme kinetics, and consequences of gene mutations are evaluated. Matters of incomplete understanding regarding the physiological roles of some vitamin D hydroxylases are critically discussed and the authors will give their view of the importance of each enzyme for vitamin D signaling. Roles of different vitamin D receptors and an alternative bioactivation pathway, leading to 20-hydroxylated vitamin D₃ metabolites, are also discussed. Considerable progress has been achieved in knowledge of the vitamin D₃ bioactivating enzymes. Nevertheless, several intriguing areas deserve further attention to understand the pleiotropic and diverse activities elicited by vitamin D signaling and the mechanisms of enzymatic activation necessary for vitamin D-induced responses.

Vitamin D: A master example of nutrigenomics

Nutrigenomics attempts to characterize and integrate the relation between dietary molecules and gene expression on a genome-wide level. One of the biologically active nutritional compounds is vitamin D₃, which activates via its metabolite 1α,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) the nuclear receptor VDR (vitamin D receptor). Vitamin D₃ can be synthesized endogenously in our skin, but since we spend long times indoors and often live at higher latitudes where for many winter months UV-B radiation is too low, it became a true vitamin. The ligand-inducible transcription factor VDR is expressed in the majority of human tissues and cell types, where it modulates the epigenome at thousands of genomic sites. In a tissue-specific fashion this results in the up- and downregulation of primary vitamin D target genes, some of which are involved in attenuating oxidative stress. Vitamin D affects a wide range of physiological functions including the control of metabolism, bone formation and immunity. In this review, we will discuss how the epigenome- and transcriptome-wide effects of 1,25(OH)₂D₃ and its receptor VDR serve as a master example in nutrigenomics. In this context, we will outline the basis of a mechanistic understanding for personalized nutrition with vitamin D₃.

An overview of vitamins as epidrugs for colorectal cancer prevention

Gene expression altering epigenomic modifications such as DNA methylation, histone modification, and chromosome remodeling is crucial to regulating many biological processes. Several lifestyle factors, such as diet and natural, bioactive food compounds, such as vitamins, modify epigenetic patterns. However, epigenetic dysregulation can increase the risk of many diseases, including cancer. Various studies have provided supporting and contrasting evidence on the relationship between vitamins and cancer risk. Though there is a gap in knowledge about whether dietary vitamins can induce epigenetic modifications in the context of colorectal cancer (CRC), the possibility of using them as epidrugs for CRC treatment is being explored. This is promising because such studies might be informative about the most effective way to use vitamins in combination with DNA methyltransferase inhibitors and other approved therapies to prevent and treat CRC. This review summarizes the available epidemiological and observational studies involving dietary, circulating levels, and supplementation of vitamins and their relationship with CRC risk. Additionally, using available in vitro, in vivo, and human observational studies, the role of vitamins as potential epigenetic modifiers in CRC is discussed. This review is focused on the action of vitamins as modifiers of DNA methylation because aberrant DNA methylation, together with genetic alterations, can induce the initiation and progression of CRC. Although this review presents some studies with promising results, studies with better study designs are necessary. A thorough understanding of the underlying molecular mechanisms of vitamin-mediated epigenetic regulation of CRC genes can help identify effective therapeutic targets for CRC prevention and treatment.

Low 25 (OH) vitamin D levels are associated with increased prevalence of nonalcoholic fatty liver disease and significant liver fibrosis

AIMS

Evidence on the role of 25-Hydroxyvitamin D (25(OH)D) in the occurrence and progression of nonalcoholic fatty liver disease (NAFLD) is conflicting and population-based data are scarce. Here, we assess the association between 25(OH)D levels, NAFLD and liver fibrosis in the general population.

MATERIALS AND METHODS

This is an analysis of data from the 2017-2018 cycle of the National Health and Nutrition Examination Survey. We included adult participants with available data on vibration-controlled transient elastography (VCTE) and without viral hepatitis and significant alcohol consumption. Steatosis and fibrosis were diagnosed by the median values of controlled attenuation parameter (CAP) and liver stiffness measurement (LSM), respectively. 25(OH)D was measured by high performance liquid chromatography-tandem mass spectrometry.

RESULTS

A total of 3970 participants (1928 men and 2042 women) were included in the study. The prevalence of NAFLD (CAP ≥ 274 dB/m) and significant liver fibrosis (LSM ≥ 8 kPa) were 41.7% (95% CI 39.4-44.0) and 8.4% (95% CI 7.0-9.9), respectively, while 21.1% (95% CI 17.3-25.4) of participants had low 25(OH)D levels (<50 nmol/L). A multivariable logistic regression model adjusted for age, sex, race-ethnicity, body mass index, waist circumference, calendar period, diabetes, chronic kidney disease, and vitamin D supplementation showed that compared with participants with low 25(OH)D, those with optimal levels (≥75 nmol/L) had lower odds of both NAFLD (OR 0.73, 95% CI 0.55-0.98 p = 0.038) and significant liver fibrosis (OR 0.65, 95% CI 0.44-0.96, p = 0.033).

CONCLUSIONS

An inverse relationship was found between 25(OH)D and NAFLD and fibrosis, suggesting a possible role of vitamin D in NAFLD occurrence and progression.

Urine trace element disorder along with renal function injury in vitamin D deficient diabetic rats and intervention effect of 1α,25-dihydroxyvitamin D3

Introduction

Trace element metabolism disorders are often secondary to disorders of glucose metabolism in diabetes. Although 1α,25-dihydroxyvitamin D3 [1,25(OH)₂D₃] could ameliorate abnormal glucose metabolism in the development of diabetes, the effect on trace element metabolism is unclear. The objective of this study was to evaluate the influence of 1,25(OH)₂D₃ on urinary excretions of trace elements in Zucker diabetic fatty (ZDF) rats.

Methods

At 6 weeks of age, male ZDF (n = 40) rats were subdivided into four groups: diabetic model (ZDF), low-dose (ZDF + VL, 2 μg/kg⋅bw), middle-dose (ZDF + VM, 8 μg/kg⋅bw) and high-dose (ZDF + VH, 16 μg/kg⋅bw) 1,25(OH)₂D₃ groups. Another 10 Zucker lean (ZL) rats served as a control group. All rats were given vitamin D deficient Purina #5008 chow and the intervention groups were given the corresponding dose of 1,25(OH)₂D₃ by gavage on alternate days for 7 weeks. Microalbuminuria (MALB) and urinary creatinine concentration were detected by a biochemical autoanalyzer. Urine trace element concentrations were measured using inductively coupled plasma mass spectrometry (ICP-MS) and were corrected by urinary creatinine.

Results

Throughout the intervention phase, MALB, UACR and urinary creatinine levels in the ZDF group were significantly higher than those in the ZL group, and showed a gradual increase with the prolongation of the intervention time. These changes were reversed in a dose-dependent manner after 1,25(OH)₂D₃ intervention (P < 0.05). Correspondingly, most of the urinary trace element excretions in the ZDF rats were significantly increased compared with the ZL group, and 1,25(OH)₂D₃ intervention significantly reduced the urinary copper (Cu), zinc (Zn), selenium (Se) and molybdenum (Mo) levels in the ZDF rats (P < 0.05), especially in the medium and high dose groups.

Conclusion

1,25(OH)₂D₃ had improvement effects on urinary Cu, Zn, Se, and Mo excretions in ZDF rats, suggesting that it may be related to the reduction of diabetic renal impairment and renal oxidative damage.

Interaction of Vitamin D with Peptide Hormones with Emphasis on Parathyroid Hormone, FGF23, and the Renin-Angiotensin-Aldosterone System

The seminal discoveries that parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23) are major endocrine regulators of vitamin D metabolism led to a significant improvement in our understanding of the pivotal roles of peptide hormones and small proteohormones in the crosstalk between different organs, regulating vitamin D metabolism. The interaction of vitamin D, FGF23 and PTH in the kidney is essential for maintaining mineral homeostasis. The proteohormone FGF23 is mainly secreted from osteoblasts and osteoclasts in the bone. FGF23 acts on proximal renal tubules to decrease production of the active form of vitamin D (1,25(OH)₂D) by downregulating transcription of 1α-hydroxylase (CYP27B1), and by activating transcription of the key enzyme responsible for vitamin D degradation, 24-hydroxylase (CYP24A1). Conversely, the peptide hormone PTH stimulates 1,25(OH)₂D renal production by upregulating the expression of 1α-hydroxylase and downregulating that of 24-hydroxylase. The circulating concentration of 1,25(OH)₂D is a positive regulator of FGF23 secretion in the bone, and a negative regulator of PTH secretion from the parathyroid gland, forming feedback loops between kidney and bone, and between kidney and parathyroid gland, respectively. In recent years, it has become clear that vitamin D signaling has important functions beyond mineral metabolism. Observation of seasonal variations in blood pressure and the subsequent identification of vitamin D receptor (VDR) and 1α-hydroxylase in non-renal tissues such as cardiomyocytes, endothelial and smooth muscle cells, suggested that vitamin D may play a role in maintaining cardiovascular health. Indeed, observational studies in humans have found an association between vitamin D deficiency and hypertension, left ventricular hypertrophy and heart failure, and experimental studies provided strong evidence for a role of vitamin D signaling in the regulation of cardiovascular function. One of the proposed mechanisms of action of vitamin D is that it functions as a negative regulator of the renin-angiotensin-aldosterone system (RAAS). This finding established a novel link between vitamin D and RAAS that was unexplored until then. During recent years, major progress has been made towards a more complete understanding of the mechanisms by which FGF23, PTH, and RAAS regulate vitamin D metabolism, especially at the genomic level. However, there are still major gaps in our knowledge that need to be filled by future research. The purpose of this review is to highlight our current understanding of the molecular mechanisms underlying the interaction between vitamin D, FGF23, PTH, and RAAS, and to discuss the role of these mechanisms in physiology and pathophysiology.

The Efficacious Benefit of 25-Hydroxy Vitamin D to Prevent COVID-19: An In-Silico Study Targeting SARS-CoV-2 Spike Protein

The environment has rapidly looked at proven specialist task forces in the aftermath of the COVID-19 pandemic to build public health policies and measures to mitigate the effects of emerging coronaviruses. According to the researchers, taking 10 μg of 25-hydroxy vitamin D daily is recommended to keep us safe. There have been several studies recently indicating that there is a reduced risk of contracting Coronavirus by 25-hydroxy vitamin D consumption, even though there is no scientific data to prove that one would not affect the COVID-19 viral infection by 25-hydroxy vitamin D consumption. In this regard, the present study investigates the important literature and the role of 25-hydroxy vitamin D to prevent COVID-19 infection by conducting an in-silico study with SARS-CoV-2 spike protein as a target. Lopinavir, a previously reported drug candidate, served as a reference standard for the study. MD simulations were carried out to improve predictions of receptor-ligand complexes which offer novelty and strength to the current study. MD simulation protocols were explored and subjected to 25-hydroxy vitamin D and a known drug, Lopinavir. Comparison of ligands at refined models to the crystal structure led to promising results. Appropriate timescale simulations have been used to understand the activation mechanism, the role of water networks for receptor function, and the ligand binding process. Furthermore, MD simulations in combination with free energy calculations have also been carried out for lead optimization, evaluation of ligand binding modes, and assessment of ligand selectivity. From the results, 25-hydroxy vitamin D was discovered to have the vital interaction and highest potency in LBE, lower RMSD, and lower inhibition intensity similar to the standard. The findings from the current study suggested that 25-hydroxy vitamin D would be more effective in treating COVID-19. Compared with Lopinavir, 25-hydroxy vitamin D had the most potent interaction with the putative binding sites of the SARS-CoV-2 spike protein of COVID-19.

Beneficial effects of vitamin D in the management of untreated hyperlipidemia in diabetic patients in Erbil, Iraq

Hyperlipidemia is highly prevalent among type 2 diabetes mellitus (T2DM) patients. As hyperlipidemia plays a major part in atherosclerosis development and progression, this occurrence is linked to a significantly raised risk of cardiovascular disease. This study aims to assess the effects of vitamin D supplementation on lipid parameters in T2DM patients with untreated hyperlipidemia. Thirty-five T2DM patients with hyperlipidemia and vitamin D deficiency were supplemented with vitamin D for three months. Serum 25-hydroxyvitamin D (25[OH]D), calcium, lipid parameters, atherogenic indices, glucose, and HbA1c were recorded before and after the intervention. After supplementation, there was a statistically significant reduction in VLDL-C and triglycerides. Triglycerides showed a significant negative correlation with 25(OH)D. Atherogenic indices and HDL-C also improved significantly. Vitamin D supplementation had beneficial effects on the lipid profile of T2DM patients with untreated hyperlipidemia and vitamin D deficiency. Thus, vitamin D could be a valuable adjuvant therapy for these patients.

Association Between Vitamin D Binding Protein Gene Polymorphism (rs7041), Vitamin D Receptor, and 25-Hydroxyvitamin D Serum Levels With Prostate Cancer in Kurdish Population in West of Iran

Prostate cancer (PCa) pathology has been linked to vitamin D, vitamin D receptors (VDRs), and vitamin D binding proteins (VDBPs). We sought to investigate the association between VDR rs2228570 and rs1544410 as well as VDBP rs7041 polymorphisms and serum 25-hydroxyvitamin D (25(OH)-vitamin D) levels in PCa patients. Blood samples were collected from 111 PCa patients and 150 age-matched healthy volunteers. The VDR rs2228570 T/C, rs1544410 G/A, and VDBP rs7041 T/G genotypes were determined using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). 25(OH)-vitamin D and PSA (Total and Free) serum levels were measured. The frequencies of VDBP genotypes T/G vs. T/T (56.5% vs. 44.5%, p = 0.01) according to the dominant model T/G + G/G vs. T/T (84.3% vs. 71.5%, p = 0.01) were significantly higher in PCa patients when compared to control group and considerably increased the risk of disease by 2.29, 1.44, and 2.13 folds respectively. Interestingly, the results demonstrated that PCa patients with the dominant model (T/G + G/G vs. T/T) of VDBP had significantly lower serum levels of vitamin D and higher serum levels of total and free PSA in comparison to the controls. Furthermore, when compared to controls, PCa patients with the dominant model T allele (T/G + G/G vs. TT) of VDBP had significantly higher vitamin D, total PSA, and free PSA concentrations. Serum levels of 25(OH)-vitamin D and rs7041 T/G polymorphism of the VDBP gene could be potential risk factors for PCa.

Vitamin D Receptor and Its Influence on Multiple Sclerosis Risk and Severity: From Gene Polymorphisms to Protein Expression

Multiple sclerosis (MS) is a multifactorial neurodegenerative disease. Low levels of vitamin D are a risk factor for MS and alterations in the vitamin D receptor (VDR) might be a risk factor as well. This study aimed to evaluate whether the VDR rs731236 (Taq-I) and rs4334089 (HpyCH4V) gene polymorphisms and VDR protein expression are associated with MS risk and severity. Vitamin D plasma levels were analyzed in a group of patients. Additional analyses of VDR protein expression and vitamin D levels of patients with different forms of MS (MSSS < 3 and MSSS ≥ 3) were performed. The analysis of the genotypic and allelic frequencies revealed that the rs731236 (Taq-I) gene polymorphism is significantly associated with MS presence. Although the total, cytosolic and nuclear VDR protein contents do not change between MS patients and healthy controls and between patients with different MS severity, vitamin D levels decrease in parallel with an increase in MSSS.

The Use of Dietary Supplements and Amino Acid Restriction Interventions to Reduce Frailty in Pre-Clinical Models

Frailty is a state of accelerated aging that increases susceptibility to adverse health outcomes. Due to its high societal and personal costs, there is growing interest in discovering beneficial interventions to attenuate frailty. Many of these interventions involve the use of lifestyle modifications such as dietary supplements. Testing these interventions in pre-clinical models can facilitate our understanding of their impact on underlying mechanisms of frailty. We conducted a narrative review of studies that investigated the impact of dietary modifications on measures of frailty or overall health in rodent models. These interventions include vitamin supplements, dietary supplements, or amino acid restriction diets. We found that vitamins, amino acid restriction diets, and dietary supplements can have beneficial effects on frailty and other measures of overall health in rodent models. Mechanistic studies show that these effects are mediated by modifying one or more mechanisms underlying frailty, in particular effects on chronic inflammation. However, many interventions do not measure frailty directly and most do not investigate effects in both sexes, which limits their applicability. Examining dietary interventions in animal models allows for detailed investigation of underlying mechanisms involved in their beneficial effects. This may lead to more successful, translatable interventions to attenuate frailty.

Effect of Vitamin D Supplementation on Postoperative Outcomes in Cardiac Surgery Patients: A Systematic Review

Background Vitamin D deficiency is a very common occurrence in cardiac patients. It has been proved that cardiac surgery and cardiopulmonary bypass accelerate the deficiency further. The postoperative outcomes of patients deteriorate in the presence of vitamin D deficiency. Perioperative supplementation of vitamin D is the only solution to the problem. Hence, the present systematic review was conducted to derive the efficacy and safety of vitamin D supplementation on postoperative outcomes in cardiac surgery patients.

Method Publications over duration of last 10 years was searched from different database and web sites. The data from full-text research articles were analyzed for the effect on different postoperative outcomes and side effects.

Result Eight randomized control trials were retrieved on the effect of perioperative vitamin D supplementation in cardiac surgery patients and their postoperative outcomes. Six articles (75%) were found to be in favor of improvement in postoperative outcome. Two articles (25%) did not find any difference of outcome between the control and treatment group. All the studies observed the restoration of vitamin D to normal and no adverse effects from supplementation.

Conclusion Perioperative vitamin D supplementation improves the postoperative outcomes after cardiac surgery. It is effective and safe to supplement vitamin D in cardiac surgery patients.

VDR mediated HSD3B1 to regulate lipid metabolism and promoted testosterone synthesis in mouse Leydig cells

BACKGROUND

The vitamin D receptor (VDR) mediates the pleiotropic biological actions that include osteoporosis, immune responses and androgen synthesis wherein the VDR transcriptionally regulates expression of the genes involved in this complex process. 3β-Hydroxysteroid dehydrogenase-1 (HSD3B1) is an absolutely necessary enzyme for androgen synthesis.

OBJECTIVE

The purpose of the present study was to explore the molecular mechanism of VDR mediated HSD3B1 regulation of lipid metabolism and testosterone synthesis.

METHODS

The levels of VDR, HSD3B1 and lipid metabolism associated protein were determined by quantitative real-time polymerase chain reaction (RT-qPCR) or western blot. The levels of testosterone concentrations in cell culture media serum by enzyme-linked immunosorbent assay (ELISA). Targeted relationship between VDR and Hsd3b1 was evaluated by dual-luciferase reporter assay.

RESULTS

Based on the data analysis of mouse testicular proteome, we found that the expression of HSD3B1 was significantly reduced after VDR deletion. Here, we identified that Hsd3b1 was widely expressed in different tissues of mice by RT-qPCR, and was highly expressed in testis, and mainly located in testicular Leydig cells. Dual-luciferase assay confirmed that VDR could bind candidate vitamin D responsive elements (VDREs) in upstream region of Hsd3b1, and enhance gene expression. Furthermore, over-expression VDR and HSD3B1 significantly increased testosterone synthesis in mice Leydig cells. Meanwhile, Lpl expression was significantly down-regulated and Angptl4 expression was significantly up-regulated in the present of HSD3B1 overexpression. Both LPL and ANGPTL4 play important roles in regulating lipid metabolism.

CONCLUSIONS

The present study unveiled VDR mediated HSD3B1 to regulate lipid metabolism and promoted testosterone synthesis in mouse Leydig cells. These findings will greatly help us to understand the roles of VDR and HSD3B1 in testosterone synthesis and lipid metabolism.

A decrease in serum 1,25(OH)2D after elective hip replacement and during bone healing is associated with changes in serum iron and plasma FGF23

OBJECTIVE

Although calcitriol is essential for bone healing, its serum concentrations are low after hip surgery, and they continue to decline during bone healing. This study aimed to test the hypothesis of an association of changes in calcitriol production with the status of fibroblast growth factor 23 (FGF23) and iron deficiency after elective hip replacement for coxarthrosis.

METHODS

In this prospective study, we measured the biomarkers of 17 patients undergoing elective hip replacement on admission, on the first day after surgery, and at the regular check-up after 48 ± 8 days. The serum concentrations of 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, transferrin, ferritin, parathyroid hormone, intact plasma FGF23 (iFGF23) and C-terminal FGF23 (cFGF23) were determined.

RESULTS

In our patients who underwent elective hip replacement, significant correlations existed between the percent change in the conversion rate of 25(OH)D to 1,25(OH)₂D, plasma intact to C-terminal FGF23 ratio, and serum iron.

CONCLUSIONS

The production of calcitriol is compromised after elective hip replacement surgery, leading to reduced levels of active vitamin D in the serum. Significant correlations between the percent change in the conversion rate of 25(OH)D to 1,25(OH)₂D, plasma intact to C-terminal FGF23 ratio, and serum iron on the first day as well as 7 weeks after surgery could inspire future studies to determine whether and how calcitriol deficiency should be corrected, especially in fracture cases.

The Role of Vitamin D in Supporting Health in the COVID-19 Era

The genomic activity of vitamin D is associated with metabolic effects, and the hormone has a strong impact on several physiological functions and, therefore, on health. Among its renowned functions, vitamin D is an immunomodulator and a molecule with an anti-inflammatory effect, and, recently, it has been much studied in relation to its response against viral infections, especially against COVID-19. This review aims to take stock of the correlation studies between vitamin D deficiency and increased risks of severe COVID-19 disease and, similarly, between vitamin D deficiency and acute respiratory distress syndrome. Based on this evidence, supplementation with vitamin D has been tested in clinical trials, and the results are discussed. Finally, this study includes a biochemical analysis on the effects of vitamin D in the body's defense mechanisms against viral infection. In particular, the antioxidant and anti-inflammatory functions are considered in relation to energy metabolism, and the potential, beneficial effect of vitamin D in COVID-19 is described, with discussion of its influence on different biochemical pathways. The proposed, broader view of vitamin D activity could support a better-integrated approach in supplementation strategies against severe COVID-19, which could be valuable in a near future of living with an infection becoming endemic.

Insights into the perspective correlation between vitamin D and regulation of hormones: sex hormones and prolactin

Aim. Vitamin D is currently an exciting research target, besides its obvious role in calcium homeostasis and bone health, enormous work is being directed at examining the effects of this vitamin on various biological functions and pathological conditions.

Material and methods. The review of the literature and the analysis took about six months and was carried out through PubMed. This is a search engine opening mainly the MEDLINE database of trusted references. We called up all studies written in English that were published between the years 2004 to 2021 and that came through using the applied search terms, and analysed all those that met the criteria.

Results. The endocrine system with its many glands and hormones and their essential roles in the maintenance of normal body functioning cannot be far from interactions with vitamin D. Male and female sex hormones are no exceptions and many studies have investigated the correlations between these hormones and vitamin D. As such, direct and indirect relationships have been found between vitamin D, its receptors or one of its metabolising enzymes with sex hormones and the development of reproductive organs in males and females.

Conclusion. This review summarises the research investigating the associations of vitamin D with sex hormones and reproductive organs in males and females, and thus may pave the road for future studies that will investigate the clinical significance of vitamin D in the management of reproductive system disorders. Despite some conflicting results about the relationship between VD and the effectiveness of the reproductive system, many studies confirm the presence of receptors for this vitamin in the reproductive system, and this supports the direct or indirect relationship between VD and prolactin or VD and testosterone through PO4 and Ca2+ homeostasis, or production of osteocalcin. Therefore, VD is positively associated with semen quality and androgen status. Furthermore, a direct relationship between VD and the production of progesterone, estrogen and estrone in human ovarian cells has been supported by many studies.

FGF23 and Vitamin D Metabolism

Apart from its phosphaturic action, the bone-derived hormone fibroblast growth factor-23 (FGF23) is also an essential regulator of vitamin D metabolism. The main target organ of FGF23 is the kidney, where FGF23 suppresses transcription of the key enzyme in vitamin D hormone (1,25(OH)₂D) activation, 1α-hydroxylase, and activates transcription of the key enzyme responsible for vitamin D degradation, 24-hydroxylase, in proximal renal tubules. The circulating concentration of 1,25(OH)₂D is a positive regulator of FGF23 secretion in bone, forming a feedback loop between kidney and bone. The importance of FGF23 as regulator of vitamin D metabolism is underscored by the fact that in the absence of FGF23 signaling, the tight control of renal 1α-hydroxylase fails, resulting in overproduction of 1,25(OH)₂D in mice and men. During recent years, big strides have been made toward a more complete understanding of the mechanisms underlying the FGF23-mediated regulation of vitamin D metabolism, especially at the genomic level. However, there are still major gaps in our knowledge that need to be filled by future research. Importantly, the intracellular signaling cascades downstream of FGF receptors regulating transcription of 1α-hydroxylase and 24-hydroxylase in proximal renal tubules still remain unresolved. The purpose of this review is to highlight our current understanding of the molecular mechanisms underlying the regulation of vitamin D metabolism by FGF23, and to discuss the role of these mechanisms in physiology and pathophysiology. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

Correlation between Pre-Operative 25-Hydroxyvitamin D Levels and Poor Prognostic Factors for Papillary Thyroid Cancer

PURPOSE

To evaluate the relationship between pre-operative 25-hydroxyvitamin D (25 (OH) D) levels and poor prognostic factors for papillary thyroid cancer (PTC).

METHODS

A total of 1161 patients diagnosed with PTC were analyzed retrospectively. The patients were categorized .based on their pre-operative 25 (OH) D levels into three groups: the severe vitamin D deficiency (VDD) group (25 (OH) D < 10 ng/mL), moderate VDD group (20 ng/mL > 25 (OH) D ≥ 10 ng/mL), and control group (25(OH)D ≥ 20 ng/mL) Differences in the demographic and clinicopathological characteristics among the three groups were analyzed. Linear and logistic regression analyses were also performed to determine the effect of 25 (OH) D levels on the established poor prognostic factors for PTC.

RESULTS

We observed a negative correlation between 25 (OH) D levels and tumor size (r = -0.067, P = 0.049). Severe VDD and moderate VDD were independently associated with lymph node metastasis and distant metastasis diagnosed during surgery (P = 0.00, odds ratio (OR) = 4.11; P = 0.00, OR = 3.33, respectively). After adjusting parameters such as sex, age, body mass index, and thyroid-stimulating hormone (TSH) levels, severe VDD and moderate VDD were found to be closely associated with advanced cancer stage (stage III or IV) (P = 0.018, OR = 3.02; P = 0.041, OR = 3.60, respectively). Additionally, a significant correlation (P = 0.007) was observed between the pre-operative 25 (OH) D and TSH levels.

CONCLUSION

25 (OH) D levels were significantly associated with certain poor prognostic factors for PTC, including larger tumor diameter and the occurrence of lymph node metastasis. More prospective studies are needed to evaluate whether the assessment and supplementation of vitamin D contributes to the pre-operative management of patients with PTC.

Effects of vitamin D-related gene polymorphisms on attempted suicide

OBJECTIVE

Emerging evidence suggests that vitamin D might protect from attempted suicide. The study aimed to investigate the associations between single-nucleotide polymorphisms (SNPs) related to vitamin D levels identified in a large genome-wide association study and attempted suicide in rural China.

METHODS

This 1:1 matched case-control study included altogether 510 suicide attempters and 510 community controls. Genotypes of four target SNPs (DHCR7-rs12785878, CYP2R1-rs10741657, GC-rs2282679, and CYP24A1-rs6013897) were determined, and a genetic risk score (GRS) was constructed to evaluate the combined effect of them. Demographic and psychological information was acquired through face-to-face interviews.

RESULTS

The A allele of CYP24A1-rs6013897 was significantly associated with attempted suicide (OR = 1.27, 95% CI, 1.03-1.58, P = 0.029), even after adjusting for demographic and psychological confounders (adjusted OR = 1.53, 95% CI, 1.01-2.30, P = 0.043). The GRS analyses revealed a significantly higher risk of attempted suicide with a greater number of low vitamin D alleles (adjusted OR = 1.33, 95% CI, 1.13-1.58, P < 0.001). Subgroup analyses stratified by sex indicated that the genetic associations were only significant among males with adjusted ORs of 3.77 (95% CI, 1.56-9.10) for the A allele of rs6013897 and 2.04 (95% CI, 1.32-3.17) for GRS.

CONCLUSIONS

Our findings identity CYP24A1-rs6013897 as a potential biomarker for attempted suicide and indicate that a genetic predisposition to lower vitamin D levels may contribute to attempted suicide. It suggests the possibility that vitamin D may have the preventive potential for attempted suicide.

Revisiting food-sourced vitamins for consumer diet and health needs: a perspective review, from vitamin classification, metabolic functions, absorption, utilization, to balancing nutritional requirements

The significant attention gained by food-sourced vitamins has provided insights into numerous current researches; for instance, the potential reversal of epigenetic age using a diet and lifestyle intervention, the balance between food and dietary supplements in the general population, the role of diet and food intake in age-related macular degeneration, and the association of dietary supplement use, nutrient intake and mortality among adults. As relevant literature about food-sourced vitamin increases, continuous synthesis is warranted. To supplement existing information, this perspective review discussed food-sourced vitamins for consumer diet and health needs, scoping from vitamin absorption, metabolic functions, utilization, to balancing nutritional requirements. Relevant literatures were identified through a search of databases like Google Scholar, Web of Science, the Interscience Online Library, ScienceDirect, and PubMed. We demonstrated that vitamins whether from plant- and animal-based sources are prerequisites for the metabolic functions of the human body. The fat- and water-soluble classification of vitamins remains consistent with their respective absorption and dissolution potentials, underpinned by numerous physiological functions. Vitamins, largely absorbed in the small intestine, have their bioavailability dependent on the food composition, its associated interactions, as well as alignment with their metabolic functions, which involves antioxidants, coenzymes, electron acceptor/donor, and hormones. Moreover, vitamin deficiencies, in every form, pose a serious threat to human health. Vitamin toxicities remain rare, but can still occur mainly from supplementation, although it appears much less in water-soluble vitamins of which some excesses get readily removed by the human body, different from the fat-soluble ones that are stored in tissues and organs. Besides discussions of absorption, transport, and cellular uptake of vitamins, this perspective review also included approaches to meeting vitamin requirements and therapeutic strategies against micronutrient deficiency and COVID-19. We have also attempted on how to strike the balance between food-sourced vitamins and dietary supplements.

Transmol: repurposing a language model for molecular generation

Recent advances in convolutional neural networks have inspired the application of deep learning to other disciplines. Even though image processing and natural language processing have turned out to be the most successful, there are many other domains that have also benefited; among them, life sciences in general and chemistry and drug design in particular. In concordance with this observation, from 2018 the scientific community has seen a surge of methodologies related to the generation of diverse molecular libraries using machine learning. However to date, attention mechanisms have not been employed for the problem of de novo molecular generation. Here we employ a variant of transformers, an architecture recently developed for natural language processing, for this purpose. Our results indicate that the adapted Transmol model is indeed applicable for the task of generating molecular libraries and leads to statistically significant increases in some of the core metrics of the MOSES benchmark. The presented model can be tuned to either input-guided or diversity-driven generation modes by applying a standard one-seed and a novel two-seed approach, respectively. Accordingly, the one-seed approach is best suited for the targeted generation of focused libraries composed of close analogues of the seed structure, while the two-seeds approach allows us to dive deeper into under-explored regions of the chemical space by attempting to generate the molecules that resemble both seeds. To gain more insights about the scope of the one-seed approach, we devised a new validation workflow that involves the recreation of known ligands for an important biological target vitamin D receptor. To further benefit the chemical community, the Transmol algorithm has been incorporated into our cheML.io web database of ML-generated molecules as a second generation on-demand methodology.