Evolution of our understanding of vitamin D

Ethnic Differences in Response to Oral Vitamin D Supplementation: A Systematic Review and Meta-analysis

CONTEXT

Individual variability in oral vitamin D supplement response hinders the understanding of its clinical impact, and while ethnicity has been implicated in this variability it has not been well described.

OBJECTIVE

The aim was to systematically assess the impact of ethnicity on response to oral vitamin D supplementation.

DATA SOURCE

The Web of Science and PubMed databases were searched for articles published from 1960 to the end of 2020. All trials in adults measuring 25(OH)D3 blood levels were included.

DATA EXTRACTION

Two reviewers independently extracted the data from the eligible studies. The change in 25(OH)D3 blood levels (95% CI) and P values were extracted, and grouped according to ethnicity, then subjected to random-effects meta-analysis. The primary outcome measurement was mean serum 25(OH)D3 levels and the secondary outcome was dose-adjusted mean serum 25(OH)D3 levels, both compared with baseline.

DATA ANALYSIS

A total of 18 studies were identified, and data from 1131 participants were extracted. Body mass index (BMI) and dose were significant covariates (Pearson correlation coefficient, P = .016 and .017) and were normalized in the meta-analysis to minimize heterogeneity, but latitude was not (P = .66). Meta-analysis showed an effect of ethnicity on dose and BMI-adjusted mean serum 25(OH)D3 levels compared with baseline (P < .00001, I2 = 98%). Asian and White study participants demonstrated a statistically higher increase in dose and BMI-adjusted 25(OH)D3 blood levels (183 nmol/L [95% CI, 163-203] and 173 nmol/L [95% CI, 152-194], respectively), compared with Arab and Black study participants (37 nmol/L [95% CI, 35-39] and 99 nmol/L [95% CI, 90-108]) using repeated t tests. Sensitivity analysis demonstrated that these findings were not impacted by potential study bias or the inclusion of immigrant populations.

CONCLUSION

Ethnicity had an impact on oral vitamin D response. Further prospective studies should examine if ethnicity-based dose stratification in both clinical practice and clinical trials is warranted.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023410076.

Significance of Duodenal Prolactin Receptor Modulation by Calcium and Vitamin D in Sulpiride-Induced Hyperprolactinemia

Background and Objectives: Hyperprolactinemia, as a potential side-effect of some antipsychotic medications, is associated with decreased bone density and an increased risk of fractures. This study investigates whether calcium and vitamin D supplementation affects prolactin receptor (Prlr) gene expression in the duodenum, vertebrae, and kidneys of female rats with sulpiride-induced hyperprolactinemia. Materials and Methods: Twenty-one-week-old female Wistar rats were assigned to three groups: Group S consisted of ten rats who received sulpiride injections (10 mg/kg) twice daily for 6 weeks; Group D (10 rats) received daily supplementation of 50 mg calcium and 500 IU vitamin D along with sulpiride for the last 3 weeks; and Group C consisting of seven age-matched nulliparous rats serving as a control group. Real-time PCR was used to assess Prlr gene expression in the duodenum, vertebrae, and kidneys. Results: In Group S, Prlr gene expression was notably decreased in the duodenum (p < 0.01) but elevated in the vertebrae and kidneys compared to Group C. Conversely, Group D exhibited significantly increased Prlr expression in the duodenum (p < 0.01) alongside elevated expression in the vertebrae and kidneys. Conclusions: In sulpiride-induced hyperprolactinemia, decreased Prlr gene expression in the duodenum may lead to reduced intestinal calcium absorption. Consequently, prolactin may draw calcium from the skeletal system to maintain calcium balance, facilitated by increased Prlr gene expression in the vertebrae. However, vitamin D supplementation in sulpiride-induced hyperprolactinemia notably enhances Prlr gene expression in the duodenum, potentially ameliorating intestinal calcium absorption and mitigating adverse effects on bone health.

Progress of linking gut microbiota and musculoskeletal health: casualty, mechanisms, and translational values

The musculoskeletal system is important for balancing metabolic activity and maintaining health. Recent studies have shown that distortions in homeostasis of the intestinal microbiota are correlated with or may even contribute to abnormalities in musculoskeletal system function. Research has also shown that the intestinal flora and its secondary metabolites can impact the musculoskeletal system by regulating various phenomena, such as inflammation and immune and metabolic activities. Most of the existing literature supports that reasonable nutritional intervention helps to improve and maintain the homeostasis of intestinal microbiota, and may have a positive impact on musculoskeletal health. The purpose of organizing, summarizing and discussing the existing literature is to explore whether the intervention methods, including nutritional supplement and moderate exercise, can affect the muscle and bone health by regulating the microecology of the intestinal flora. More in-depth efficacy verification experiments will be helpful for clinical applications.

Association between serum 25-hydroxyvitamin D and fasting blood glucose in osteoporosis patients

Osteoporosis (OP) is often associated with other complications, such as impaired glucose homeostasis. Vitamin D deficiency is common and has been linked to bone metabolism and the regulation of blood sugar levels. The aim of this study was to evaluate the independent relationship between serum 25-hydroxyvitamin D (25[OH]D) and fasting blood glucose levels (FBG) in a group of patients diagnosed with OP. This is a retrospective cross-sectional study from a prospectively collected database at our tertiary referral center. Consecutive 2084 OP patients who were hospitalization were finally analyzed in this study. FBG is the dependent variable, serum 25(OH)D level of OP patients is exposure variable of this study. There was a linear significantly negative association between serum 25(OH)D and FBG (β, - 0.02; 95% CI - 0.03 to - 0.01; P = 0.0011) in the fully adjusted models. Specifically, when serum 25(OH)D level was less than 23.39 ng/mL, FBG decreased by 0.04 mmol/L for every 1 ng/mL increase of serum 25(OH)D level. When serum 25(OH)D was greater than 23.39 ng/ mL, the negative association was insignificant (P = 0.9616). If the association is confirmed, the clinical management of blood glucose in OP patients with serum 25(OH)D deficiency has instructive implications.

Calcifediol: Mechanisms of Action

Due to its essential role in calcium and phosphate homeostasis, the secosteroid hormone calcitriol has received growing attention over the last few years. Calcitriol, like other steroid hormones, may function through both genomic and non-genomic mechanisms. In the traditional function, the interaction between the biologically active form of vitamin D and the vitamin D receptor (VDR) affects the transcription of thousands of genes by binding to repeated sequences present in their promoter region, named vitamin D-responsive elements (VDREs). Non-transcriptional effects, on the other hand, occur quickly and are unaffected by inhibitors of transcription and protein synthesis. Recently, calcifediol, the immediate precursor metabolite of calcitriol, has also been shown to bind to the VDR with weaker affinity than calcitriol, thus exerting gene-regulatory properties. Moreover, calcifediol may also trigger rapid non-genomic responses through its interaction with specific membrane vitamin D receptors. Membrane-associated VDR (mVDR) and protein disulfide isomerase family A member 3 (Pdia3) are the best-studied candidates for mediating these rapid responses to vitamin D metabolites. This paper provides an overview of the calcifediol-related mechanisms of action, which may help to better understand the vitamin D endocrine system and to identify new therapeutic targets that could be important for treating diseases closely associated with vitamin D deficiency.

Calcifediol: Why, When, How Much?

Vitamin D deficiency is a constantly growing health problem worldwide. Adults affected with hypovitaminosis D could experience negative consequences on their musculoskeletal system and extra-skeletal health. In fact, an optimal vitamin D status is essential to ensure the correct bone, calcium, and phosphate homeostasis. To improve vitamin D status, it is important to not only increase the intake of food fortified with vitamin D, but also to administer vitamin D supplementation when required. Vitamin D3 (cholecalciferol) is the most widely used supplement. In recent years, the administration of calcifediol (25(OH)D3), the direct precursor of the biologically active form of vitamin D3, as oral vitamin D supplementation has progressively grown. Here, we report the potential medical benefits of some peculiar biological actions of calcifediol, discussing the possible specific clinical scenarios in which the oral intake of calcifediol could be most effective to restore the correct serum levels of 25(OH)D3. In summary, the aim of this review is to provide insights into calcifediol-related rapid non-genomic responses and the possible use of this vitamin D metabolite as a supplement for the treatment of people with a higher risk of hypovitaminosis D.

Targeting 7-dehydrocholesterol reductase against EV-A71 replication by upregulating interferon response

Recent studies have shown a close link between viral infections and cholesterol metabolism. Here, we reported that 7-dehydrocholesterol reductase (DHCR7), a terminal enzyme for catalyzing cholesterol synthesis in the Kandutsch-Russell pathway, is harnessed by enterovirus A71 (EV-A71) benefitting for its replication. Overexpression of DHCR7 resulted in upregulating of EV-A71 replication, while the S14A mutation, which reduces DHCR7 enzyme activity, has no effect on EV-A71 replication. Knockdown of DHCR7 expression with small interfering RNA (siRNA) or enzyme activity inhibition with pharmacological inhibitor AY9944 could significantly inhibit EV-A71 replication. Adding cholesterol to DHCR7 knockdown cells or AY9944-treated cells could rescue EV-A71 replication. More importantly, prophylactic administration of AY9944 effectively protected mice from lethal EV-A71 infection. In addition, the natural cholesterol precursor 7-dehydrocholesterol (7-DHC), which is converted to cholesterol by DHCR7, has a similar effect against EV-A71 infection. Mechanistically, AY9944 or 7-DHC treatment can specifically promote IRF3 phosphorylation to activate interferon response. Moreover, AY9944 effectively cleared coxsackievirus B3 (CVB3) and coxsackievirus A16 (CVA16) infections in vitro. In conclusion, pharmacological modulation of DHCR7 might provide a chance for treatment of enterovirus infection, including EV-A71.

Public Knowledge, Attitude, and Practice Toward Vitamin D Deficiency in Al-Qunfudhah Governorate, Saudi Arabia

BACKGROUND

Vitamin D is a very important component of all vital functions in the human body. Its deficiency is a major public health issue worldwide and is associated with a broad spectrum of diseases. This study assessed knowledge, attitude, and practices regarding vitamin D deficiency among the general population in the Al-Qunfudhah governorate, Saudi Arabia.

METHODS

An analytical cross-sectional study was carried out among the population in Al-Qunfudhah governorate, Saudi Arabia. A self-administrated online questionnaire was utilized to collect the research data during a period of four months from November 2021 to February 2022.

RESULTS

A sample of 466 participants was recruited in this study, about two-thirds of them were females (64.4%) and had a university education (67.8%). Despite 91% of them having previously heard about vitamin D, only (17.4%) were able to recognize sunlight exposure as a main source of vitamin D. Poor knowledge and positive attitude regarding vitamin D were obviously seen among 72.3% and 95.7%. Although 89% of the participants' family members had been diagnosed with hypovitaminosis D. Only 45% of the sample were willing to be compliant with vitamin D supplement whenever it is needed. The most reported source of information regarding vitamin D among the respondents was mass media (62.2%). The associated variables of good knowledge were female gender (P 0.001), young (P 0.001), unmarried (P 0.006), highly educated (P 0.048), and receiving medical information from physicians (P 0.018).  Conclusion: This study reveals the poor level of knowledge about vitamin D deficiency among the Al-Qunfudhah population, and this negatively affected their compliance for vitamin D supplementation when having hypovitaminosis D. Positive attitude toward vitamin D deficiency among the majority of the participants was obvious and may direct them to change their behavior toward vitamin D. Therefore, this study highlights the necessity of educating and sensitizing population about vitamin D and prevention of its deficiency.

Vitamin D Deficiency in Both Oral and Systemic Manifestations in SARS-CoV-2 Infection: Updated Review

The specialized literature emphasizes the fact that vitamin D has a potentially beneficial effect in the context of the current COVID-19 pandemic. The purpose of this article is to highlight the role of vitamin D, both prophylactic and curative, in the treatment of patients diagnosed with COVID-19. Even though its relevance is still unknown and causes various controversies, there is currently no specific treatment for patients diagnosed with COVID-19. There are various prevention strategies with new vaccination schedules, but additional randomized and clinical trials are still needed to combat this pandemic. In addition to the systemic manifestations of SARS-CoV-2 infection, oral manifestations of this disease have also been described in the literature. The etiology of oral manifestations associated with COVID-19 infection and vitamin D deficiency remains controversial. In the present studies, oral manifestations such as salivary gland infections, aphthae, erythema, gingivitis, ulcers, etc. have been reported. This is a new topic, and the prevalence of manifestations is described in only a few studies, which is inconsistent with the number of COVID-19 cases reported since the beginning of the pandemic. The clinical symptomatology in patients with current COVID-19 infection is polymorphic. Whether the oral manifestation is directly caused by SARS-CoV-2 or a secondary manifestation remains an important topic to analyze and discuss.

An Overview of the Current Known and Unknown Roles of Vitamin D3 in the Female Reproductive System: Lessons from Farm Animals, Birds, and Fish

Recent studies have clearly shown that vitamin D₃ is a crucial regulator of the female reproductive process in humans and animals. Knowledge of the expression of vitamin D₃ receptors and related molecules in the female reproductive organs such as ovaries, uterus, oviduct, or placenta under physiological and pathological conditions highlights its contribution to the proper function of the reproductive system in females. Furthermore, vitamin D₃ deficiency leads to serious reproductive disturbances and pathologies including ovarian cysts. Although the influence of vitamin D₃ on the reproductive processes of humans and rodents has been extensively described, the association between vitamin D₃ and female reproductive function in farm animals, birds, and fish has rarely been summarized. In this review, we provide an overview of the role of vitamin D₃ in the reproductive system of those animals, with special attention paid to the expression of vitamin D₃ receptors and its metabolic molecules. This updated information could be essential for better understanding animal physiology and overcoming the incidence of infertility, which is crucial for optimizing reproductive outcomes in female livestock.

Efficacy and safety of a novel source of dietary 25-hydroxycholecalciferol in growing pigs

A randomized complete block design experiment was conducted to determine the safety and efficacy of supplementation of increasing concentrations of a novel, bacterial fermentation-derived vitamin D source on growth performance and tissue deposition of 25-hydroxycholecalciferol (25OHD3) in growing swine. Dietary treatments were as follows: commercial control with vitamin D3 (CON) at NRC recommended concentrations and three diets composed of CON + increasing inclusions (25, 50, and 250 µg/kg equivalent) of 25OHD3 from a novel source (CON + 25; CON + 50; and CON + 250, respectively). Pigs (n = 144) were assigned to 24 pens which were allotted to one of the four dietary treatments and fed for 42 d. Blood samples were collected for 25OHD3 concentration determination and individual body weights (BW) were measured on experimental day 0, 39, and 63. On day 42, tissues from 48 pigs (12 pigs per dietary treatment) were analyzed for 25OHD3 concentration. No differences were observed in growth performance. Day 39 serum 25OHD3 concentrations were greatest in CON + 250-fed pigs and linearly decreased as dietary 25OHD3 inclusion decreased (P < 0.0001). On day 42, tissue 25OHD3 concentrations increased linearly as 25OHD3 increased in the diet (P < 0.0001). On day 63, 21 d after dietary 25OHD3 withdrawal, serum 25OHD3 concentrations of all 25OHD3-fed pigs decreased to that of or within 2.76 ± 0.89 ng/mL of CON-fed pigs which demonstrates that feeding 250 µg/kg 25OHD3 is well tolerated by growing pigs and will clear the body within 21 d.

Dietary supplementation of 25-hydroxycholecalciferol as an alternative to cholecalciferol in swine diets: A review

25-hydroxycholecalciferol (25-OHD₃ ) formed via hepatic hydroxylation from vitamin D, cholecalciferol, represents the precursor of the biologically active vitamin D hormone, 1,25-dihydroxyvitamin D. Due to a higher absorption rate and the omission of one hydroxylation, dietary supplementation of 25-OHD₃ instead of vitamin D₃ is considered to be more efficient as plasma concentrations of 25-OHD₃ are increased more pronounced. The present review summarises studies investigating potential beneficial effects on mineral homeostasis, bone metabolism, health status and performance in sows, piglets and fattening pigs. Results are inconsistent. While most studies could not demonstrate any or only a slight impact of partial or total replacement of vitamin D₃ by 25-OHD₃ , some experiments indicated that 25-OHD₃ might alter physiological processes when animals are challenged, for example, by a restricted mineral supply.

Vitamin D resistant genes - promising therapeutic targets of chronic diseases

Vitamin D is an essential vitamin indispensable for calcium and phosphate metabolism, and its deficiency has been implicated in several extra-skeletal pathologies, including cancer and chronic kidney disease. Synthesized endogenously in the layers of the skin by the action of UV-B radiation, the vitamin maintains the integrity of the bones, teeth, and muscles and is involved in cell proliferation, differentiation, and immunity. The deficiency of Vit-D is increasing at an alarming rate, with nearly 32% of children and adults being either deficient or having insufficient levels. This has been attributed to Vit-D resistant genes that cause a reduction in circulatory Vit-D levels through a set of signaling pathways. CYP24A1, SMRT, and SNAIL are three genes responsible for Vit-D resistance as their activity either lowers the circulatory levels of Vit-D or reduces its availability in target tissues. The hydroxylase CYP24A1 inactivates analogs and prohormonal and/or hormonal forms of calcitriol. Elevation of the expression of CYP24A1 is the major cause of exacerbation of several diseases. CYP24A1 is rate-limiting, and its induction has been correlated with increased prognosis of diseases, while loss of function mutations cause hypersensitivity to Vit-D. The silencing mediator of retinoic acid and thyroid hormone receptor (SMRT) and its corepressor are involved in the transcriptional repression of VDR-target genes. SNAIL1 (SNAIL), SNAIL2 (Slug), and SNAIL3 (Smuc) are involved in transcriptional repression and binding to histone deacetylases and methyltransferases in addition to recruiting polycomb repressive complexes to the target gene promoters. An inverse relationship between the levels of calcitriol and the epithelial-to-mesenchymal transition is reported. Studies have demonstrated a strong association between Vit-D deficiency and chronic diseases, including cardiovascular diseases, diabetes, cancers, autoimmune diseases, infectious diseases, etc. Vit-D resistant genes associated with the aforementioned chronic diseases could serve as potential therapeutic targets. This review focuses on the basic structures and mechanisms of the repression of Vit-D regulated genes and highlights the role of Vit-D resistant genes in chronic diseases.

D-VITylation: Harnessing the biology of vitamin D to improve the pharmacokinetic properties of peptides and small proteins

Peptides have great potential to be potent and specific therapeutics, yet their small size leads to rapid glomerular filtration, which severely limits therapeutic applications. Although conjugation of small proteins to large polymers typically results in longer residence times, these conjugates often have a significant loss of biological activity due to steric hindrance. Here, we improve the pharmacokinetics (PK) of peptide therapeutics by harnessing the biology of vitamin D. Attachment of a small vitamin D-based molecule (D-VITylation) protects the conjugated peptide or protein from renal clearance by virtue of reversible binding to the serum-circulating vitamin D binding protein (DBP), without compromising bioactivity. Varying the conjugation site on vitamin D affects the binding to DBP, with higher affinity corresponding to a longer plasma half-life. We also demonstrate the important contribution of the peptide to the overall PK, likely due to alternative clearance mechanisms such as protease degradation and receptor-mediated cellular uptake. With a Fab antibody fragment, for which these alternate clearance mechanisms are not significant, D-VITylation increases the half-life of elimination from 14 to 61 h in rats. The PK profile in minipigs and projected lifetime in humans suggest that D-VITylation is a viable strategy to achieve once-weekly dosing of peptide therapeutics in humans.

Vitamin D Deficiency During Development Permanently Alters Liver Cell Composition and Function

Vitamin D, a fat-soluble vitamin, plays a critical role in calcium homeostasis, the immune system, and normal development. Many epidemiological cohort studies globally have found high prevalence rates of vitamin D deficiency and insufficiency, recognized as an important health issue that needs to be solved. In particular, reproductive age and pregnant women low in vitamin D status may confer risks of diseases like obesity on their offspring. While observational studies have suggested associations between prenatal vitamin D deficiency and metabolic phenotypes in offspring, not yet determined is whether prenatal vitamin D deficiency permanently alters the development of the liver, a major metabolic organ. We tested the histopathology and the transcriptomic profiles of livers from male C57BL/6J mice exposed to prenatal vitamin D deficiency through a maternal dietary intervention model. We found that prenatal vitamin D deficiency increases the prevalence of histopathological changes in the liver, and alters its gene expression profile. Cell subtype proportion analysis showed that the liver of prenatal vitamin D deficiency alters non-parenchymal cells of the liver, specifically macrophages, a subset of endothelial cells, and dendritic cells. Our results indicate the long-term memory of prenatal vitamin D deficiency exposure in the adult liver, a potential contributor to offspring health risks.

Combined Maternal and Post-Hatch Dietary Supplementation of 25-Hydroxycholecalciferol Alters Early Post-Hatch Broiler Chicken Duodenal Macrophage and Crypt Cell Populations and Their Mitotic Activity

The previous work has demonstrated that maternal supplementation of the circulating metabolite of vitamin D3 (D3), 25-hydroxycholecalciferol (25OHD3), enhances the immunocompetence of broiler chick offspring. In post-hatch broiler diets, 25OHD3 has been shown to affect intestinal morphology and improve the immune status of broilers. An experiment with a 2 × 2 factorial treatment arrangement was conducted to assess the effects of combining maternal (MDIET) and post-hatch (PDIET) dietary 25OHD3 inclusion on duodenal crypt and macrophage cell populations and mitotic activity in young broiler chickens. All diets were formulated to provide 5,000 IU of vitamin D. Broiler breeder hens were offered 1 of 2 MDIET: 5,000 IU D3 per kg of feed (MCTL) or 2,240 IU of D3 + 2,760 IU of 25OHD3 per kg of feed (M25OHD3) from week 25 to 41. Male broiler offspring (n = 480) hatched from eggs collected during week 41 of breeding age were allotted in raised floor pens (4 birds per pen from day 0 to 7 and individually allotted from day 8 to 21). Chicks were fed 1 of 2 PDIET (starter day 0 to 21): 5,000 IU D3 per kg of feed (PCTL) or 2,240 IU D3 + 2,760 IU 25OHD3 (P25OHD3). DUO samples (n = 12 birds per treatment per day) were collected on days 3, 6, 9, 12, 15, 18, and 21 for cryohistological and immunofluorescence analysis to facilitate the enumeration of the total macrophages, CD80+ macrophages (pro-inflammatory macrophages), and mitotically active cells (BrdU+) to calculate the proportion of proliferating cells (PPC) per duodenal crypt. Bird age impacted crypt PPC with the greatest PPC per duodenal crypt observed on days 3 and 9, and the lowest PPC per crypt was observed on day 21 (P < 0.0001). Broilers from the M25OHD3:PCTL treatment had a greater PPC (P =.002) than birds from the MCTL:PCTL treatment at day 3. An interaction among MDIET and PDIET was observed for proliferating macrophages at day 21 (P = 0.029) where M25OHD3:P25OHD3 birds had more proliferating macrophages than M25OHD3:PCTL-fed birds. These results indicate that combined MDIET and PDIET 25OHD3 supplementation may alter early post-hatch duodenal development and innate immunity.

Correlation of Vitamin D3, PAI-1, and HCG Hormone in Pre- and Post-Menopausal in Babylon Province

Background

Menopause is a unique event in women's life it usually occurs naturally, most often after age 50 when woman has not menstruated in 12 consecutive months. This study was planned to assess the relationship between Vitamin D3 level, PAI-1 and HCG in Babylon women at age <50 years as pre-menopausal and> 50 years as post-menopausal.

Methods

The sample were selected from a group of pre- and post-menopausal women, 30 and 50 respectively. All the tests were evaluated to measure Vitamin D3 level, PAI-1 and HCG level. The sample was collected between July 2019 and January 2020 at Merjan medical city GIT and Liver Center, Babylon province, Iraq.

Results

The result of current study revealed that there are significant differences in vitamin D3 level in various age categories within postmenopausal women (p= 0.02) also there is no significant differences in PAI-1 and HCG with in these two groups, p= 0.08 and 0.07, respectively. Also, there is significant negative correlation between vitamin D3 and PAI-1 in postmenopausal women (p. value is 0.01).

Conclusion

Indeed, postmenopausal women regarded as elderly, but they have sufficient vitamin D3 and normal PAI-I levels as markers for normal non fibrosis status.

Rapid Nontranscriptional Effects of Calcifediol and Calcitriol

Classically, a secosteroid hormone, vitamin D, has been implicated in calcium and phosphate homeostasis and has been associated with the pathogenesis of rickets and osteomalacia in patients with severe nutritional vitamin D deficiency. The spectrum of known vitamin D-mediated effects has been expanded in recent years. However, the mechanisms of how exactly this hormone elicits its biological function are still not fully understood. The interaction of this metabolite with the vitamin D receptor (VDR) and, subsequently, with the vitamin D-responsive element in the region of specific target genes leading to the transcription of genes whose protein products are involved in the traditional function of calcitriol (known as genomic actions). Moreover, in addition to these transcription-dependent mechanisms, it has been recognized that the biologically active form of vitamin D₃, as well as its immediate precursor metabolite, calcifediol, initiate rapid, non-genomic actions through the membrane receptors that are bound as described for other steroid hormones. So far, among the best candidates responsible for mediating rapid membrane response to vitamin D metabolites are membrane-associated VDR (VDRm) and protein disulfide isomerase family A member 3 (Pdia3). The purpose of this paper is to provide an overview of the rapid, non-genomic effects of calcifediol and calcitriol, whose elucidation could improve the understanding of the vitamin D₃ endocrine system. This will contribute to a better recognition of the physiological acute functions of vitamin D₃, and it could lead to the identification of novel therapeutic targets able to modulate these actions.

Vitamin D as therapeutic modulator in cerebrovascular diseases: a mechanistic perspectives

Vitamin D deficiency has been linked to several major chronic diseases, such as cardiovascular and neurodegenerative diseases, diabetes, and cancer, linked to oxidative stress, inflammation, and aging. Vitamin D deficiency appears to be particularly harmful to the cardiovascular system, as it can cause endothelial dysfunctioning and vascular abnormalities through the modulation of various downstream mechanisms. As a result, new research indicates that therapeutic approaches targeting vitamin D inadequacies or its significant downstream effects, such as impaired autophagy, abnormal pro-inflammatory and pro-oxidant reactions, may delay the onset and severity of major cerebrovascular disorders such as stroke and neurologic malformations. Vitamin D modulates the various molecular pathways, i.e., Nitric Oxide, PI3K-Akt Pathway, cAMP pathway, NF-kB Pathway, Sirtuin 1, Nrf2, FOXO, in cerebrovascular disorder. The current review shows evidence for vitamin D's mitigating or slowing the progression of these cerebrovascular disorders, which are significant causes of disability and death worldwide.

Role of vitamin D deficiency and comorbidities in COVID-19

Recent manuscripts described the incidence of vitamin D hypovitaminosis in coronavirus disease 2019 (COVID-19) patients. Vitamin D deficiency is also common in patients with comorbidities that are associated with a poor COVID-19 prognosis. In this letter, we review the literature regarding the association of comorbidities, vitamin D deficiency, and COVID-19.

Vitamin D Receptor Expression and its Clinical Significance in Papillary Thyroid Cancer

Objective: This study aimed to evaluate the association between vitamin D receptor (an essential component in the vitamin D signaling pathway) and serum vitamin D as well as its clinical significance in papillary thyroid cancer. Methods: This prospective cohort study comprised patients with thyroid tumors who visited our hospital, from 2017 to 2018. The level of vitamin D receptor expression from thyroid tissue was measured in patients with thyroid tumor and evaluated for correlation with serum vitamin D levels and clinicopathologic characteristics of papillary thyroid cancer. Data from 501 patients with papillary thyroid cancer from The Cancer Genome Atlas database were analyzed. Results: Increased vitamin D receptor protein and mRNA expression were observed in papillary thyroid cancer compared to those in normal and benign tissues. Lower vitamin D receptor protein expression was associated with high TNM stage papillary thyroid cancer and low p21 protein expression. Lower relative vitamin D receptor mRNA expression in papillary thyroid cancer was associated with low serum 25-hydroxyvitamin D level. The Cancer Genome Atlas database showed a positive correlation among mRNA expression of vitamin D receptor, CYP24A1, and p21. Conclusions: An association between decreased vitamin D receptor protein expression and advanced stage papillary thyroid cancer, and a correlation between low vitamin D receptor mRNA expression with low serum 25-hydroxyvitamin D level was observed. Low vitamin D receptor expression in papillary thyroid cancer was shown to positively correlate with low serum vitamin D level and disease aggressiveness.

In Vitro Non-Genomic Effects of Calcifediol on Human Preosteoblastic Cells

Several recent studies have demonstrated that the direct precursor of vitamin D₃, the calcifediol [25(OH)D₃], through the binding to the nuclear vitamin D receptor (VDR), is able to regulate the expression of many genes involved in several cellular processes. Considering that itself may function as a VDR ligand, although with a lower affinity, respect than the active form of vitamin D, we have assumed that 25(OH)D₃ by binding the VDR could have a vitamin’s D₃ activity such as activating non-genomic pathways, and in particular we selected mesenchymal stem cells derived from human adipose tissue (hADMSCs) for the in vitro assessment of the intracellular Ca²⁺ mobilization in response to 25(OH)D₃. Our result reveals the ability of 25(OH)D₃ to activate rapid, non-genomic pathways, such as an increase of intracellular Ca²⁺ levels, similar to what observed with the biologically active form of vitamin D₃. hADMSCs loaded with Fluo-4 AM exhibited a rapid and sustained increase in intracellular Ca²⁺ concentration as a result of exposure to 10⁻⁵ M of 25(OH)D₃. In this work, we show for the first time the in vitro ability of 25(OH)D₃ to induce a rapid increase of intracellular Ca²⁺ levels in hADMSCs. These findings represent an important step to better understand the non-genomic effects of vitamin D₃ and its role in endocrine system.

Causal Links between Hypovitaminosis D and Dysregulation of the T Cell Connection of Immunity Associated with Obesity and Concomitant Pathologies

Subclinical inflammation in morbid obesity is associated with immune activation and the development of concomitant diseases. Impaired immune homeostasis and immune cell dysregulation in adipose tissue are associated with phenotypic and functional changes in the pool of T lymphocytes and the development of chronic hypovitaminosis D. Low vitamin D levels in obesity lead to the activation, proliferation and production of pro-inflammatory mediators by T cells. Hypovitaminosis D is the cause of a decrease in the functional potential of regulatory and anti-inflammatory lymphocytes and the maintenance of the inflammatory response. The exact molecular genetic mechanisms of the effect of vitamin D on T lymphocytes have not been fully elucidated. Therefore, uncovering the functional role of T cells and their relationship to vitamin D homeostasis in the context of obesity development may contribute to the development of new pathogenetic methods for clinical prediction of the risk of metabolic, oncologic, autoimmune and infectious complications. The review presents the molecular genetic mechanisms of the effect of vitamin D on adipose tissue resident T lymphocytes and the characteristics of vitamin D receptor expression, and analyzes the phenotypic and functional characteristics of potentially pathogenic T lymphocytes in relation to the development of obesity and its associated complications.

ε2 , ε3 , and ε4 variants of ApoE; rs2228570 (VDR), rs4588 and rs7041 (VDBP) polymorphisms in patients with multiple sclerosis: A case-control study in Turkish population

AIM OF THE STUDY

Multiple sclerosis (MS) is a degenerative disease characterized by autoimmune demyelination in the central nervous system. Yet, underlined genetics or environmental markers are still controversial. The impact of vitamin D and cholesterol on disease activity has been phrased by many studies; however, the data available for the Turkish population are very limited. This study aimed to investigate the effect of vitamin D-related polymorphisms (VDBP and VDR) and cholesterol-related variants of ApoE on Turkish MS patients.

MATERIALS AND METHODS

Total DNAs were extracted from peripheral blood samples of 51 MS patients and 50 healthy volunteers. rs4588 and rs7041 polymorphisms of VDBP, rs2228570 of VDR, as well as ε2, ε3, and ε4 variants of ApoE, were investigated by RT-PCR. Biochemical parameters which thought to be associated with MS were also measured. Results were evaluated statistically.

RESULTS

Homozygous mutant genotype and G allele of rs2228570 in VDR, as well as heterozygous genotype of rs4588 in VDBP, were found statistically high in patients. Total cholesterol, triglyceride, and LDL-C levels were found significantly high, whereas HDL-C and vitamin D levels were low in patients. An association was found between rs4588 variation and high triglyceride levels. Similar correlations were found between ε2 genotype and low LDL-C level; ε3 genotype and higher LDL-C. Gender, triglyceride, HDL-C, and AA genotype in rs4588 had a significant effect on MS progression.

CONCLUSION

The variations of rs2228570 and rs4588, vitamin D deficiency, and biological parameters related to cholesterol metabolism may be associated with MS risk.

The Interdependency and Co-Regulation of the Vitamin D and Cholesterol Metabolism

Vitamin D and cholesterol metabolism overlap significantly in the pathways that contribute to their biosynthesis. However, our understanding of their independent and co-regulation is limited. Cardiovascular disease is the leading cause of death globally and atherosclerosis, the pathology associated with elevated cholesterol, is the leading cause of cardiovascular disease. It is therefore important to understand vitamin D metabolism as a contributory factor. From the literature, we compile evidence of how these systems interact, relating the understanding of the molecular mechanisms involved to the results from observational studies. We also present the first systems biology pathway map of the joint cholesterol and vitamin D metabolisms made available using the Systems Biology Graphical Notation (SBGN) Markup Language (SBGNML). It is shown that the relationship between vitamin D supplementation, total cholesterol, and LDL-C status, and between latitude, vitamin D, and cholesterol status are consistent with our knowledge of molecular mechanisms. We also highlight the results that cannot be explained with our current knowledge of molecular mechanisms: (i) vitamin D supplementation mitigates the side-effects of statin therapy; (ii) statin therapy does not impact upon vitamin D status; and critically (iii) vitamin D supplementation does not improve cardiovascular outcomes, despite improving cardiovascular risk factors. For (iii), we present a hypothesis, based on observations in the literature, that describes how vitamin D regulates the balance between cellular and plasma cholesterol. Answering these questions will create significant opportunities for advancement in our understanding of cardiovascular health.

Efficacy of using a complex of minerals and vitamins for prevention of complications in bone tissue and the digestive tract in rats with hypothyroidism

Significant consequences of hypothyroidism are impairments in all types of metabolism, including bone metabolism, pathological changes in the digestive tract and the development of deficiency of vitamins, macro-and micronutrients.The relevance of the study is due to the widespread occurrence of hypothyroidism and the feasibility of developing effective methods for the prevention of the pathology and its complications. The study was aimed at the condition of bone tissue and digestive tract in rats with hypothyroidism, as well as the effectiveness of preventive addition of a complex of vitamins and minerals. The studies were performed on rats with hypothyroidism that was caused using thyrostatic mercazolyl for 50 days, administered orally. Prophylaxis was performed by adding a prophylactic complex of vitamins P, C, D and minerals Ca, Mg, Cu, Se, Mn to the daily diet. In the bone tissue of rats, the indicators of destruction (elastase and acid phosphatase activity) and mineralization (alkaline phosphatase activity, calcium content) as well as the antioxidant state (activities of catalase, glutathione reductase, malonic dialdehyde content) were studied. In the gums and mucous membranes of the digestive tract of rats, we determined indicators of antioxidant status (catalase activity, malonic dialdehydecontent), inflammation (activities of elastase, acid phosphatase) and dysbiosis (activities of urease activity, lysozyme). In the bone tissue of rats with hypothyroidism, activation of destruction processes, reduction of calcium levels, activation of lipid peroxidation and antioxidant enzymes were found. Hypothyroidism also led to pathological disorders in the gums of rats and gastric mucosa, small and large intestine, namely – the development of inflammation, increased membrane permeability, activation of lipid peroxidation, increased contamination with opportunistic bacteria against the background of reduced antioxidant protection. In general, preventive use of the complex contributed to the normalization of the studied parameters in the gums, mucous membranes of the stomach, intestines, as well as remodeling processes and antioxidant-prooxidative state in the bone tissue of animals with hypothyroidism. In the conditions of hypothyroidism, the proposed complex of vitamins and minerals provided notable antioxidant, anti-inflammatory and antidysbiotic effects in the tissues of the gastrointestinal tract, thus overcoming the calcium deficiency in the blood and stopping the destructive and oxidative processes in the bone tissue of animals with hypothyroidism.

Up-regulated long noncoding RNA AC007128.1 and its genetic polymorphisms associated with Tuberculosis susceptibility

Background

Tuberculosis (TB) remains a major public health problem. Long non-coding RNAs (lncRNAs) are important regulators of gene expression. In this study, we explored the association between the expression of lncRNA AC007128.1 and TB susceptibility.

Methods

Three single-nucleotide polymorphisms (SNPs) (rs12333784, rs6463794, and rs720964) of lncRNA AC007128.1 were selected using the 1000 Genomes Project database and offline software Haploview V4.2, and were genotyped by a customized 2×48-Plex SNPscan™ Kit.

Results

We identified two differentially expressed lncRNA including AC007128.1 and AP001065.3 in comparisons of expression profiles between ATB vs. LTBI, LTBI vs. HCs, and AC700128.1 expression was specifically and significantly up-regulated in TB patients by verification of external data. Gene Ontology functional enrichment analysis and co-expression network showed up-regulated mRNA was mainly involved in negative regulation of the G protein-coupled receptor (GPCR) signaling pathway, and FPR1 and CYP27B1 were involved in the co-expression of AC007128.1. Using the 1000 Genomes Project, software Haploview V4.2, and SNP genotype, we screened out SNP rs12333784 which locus at 7p21.3 in AC007128.1 associated with TB susceptibility. The G carrier of rs12333784 was then finally verified to be significantly associated with pulmonary TB (PTB) and extrapulmonary tuberculosis (EPTB) susceptibility (pBonferroni =0.03878), and a similar but more significant effect was observed under the dominant model analysis (pBonferroni =0.013, OR =1.349, 95% CI, 1.065–1.709). In addition, the GG + GA genotype of SNP rs12333784 was significantly correlated with higher glucose (GLU) (P=0.03), higher gamma-glutamyl transferase (GGT) (P=0.05), and higher erythrocyte sedimentation rate (ESR) (P=0.05).

Conclusions

Our findings show lncRNA AC007128.1 can be regarded as biomarkers discriminating between ATB and LTBI and may also be a diagnostic biomarker for LBTI. These findings may aid clinical decision making in the management of TB.

Molecular and physical technologies for monitoring fluid and electrolyte imbalance: A focus on cancer population

Several clinical examinations have shown the essential impact of monitoring (de)hydration (fluid and electrolyte imbalance) in cancer patients. There are multiple risk factors associated with (de)hydration, including aging, excessive or lack of fluid consumption in sports, alcohol consumption, hot weather, diabetes insipidus, vomiting, diarrhea, cancer, radiation, chemotherapy, and use of diuretics. Fluid and electrolyte imbalance mainly involves alterations in the levels of sodium, potassium, calcium, and magnesium in extracellular fluids. Hyponatremia is a common condition among individuals with cancer (62% of cases), along with hypokalemia (40%), hypophosphatemia (32%), hypomagnesemia (17%), hypocalcemia (12%), and hypernatremia (1-5%). Lack of hydration and monitoring of hydration status can lead to severe complications, such as nausea/vomiting, diarrhea, fatigue, seizures, cell swelling or shrinking, kidney failure, shock, coma, and even death. This article aims to review the current (de)hydration (fluid and electrolyte imbalance) monitoring technologies focusing on cancer. First, we discuss the physiological and pathophysiological implications of fluid and electrolyte imbalance in cancer patients. Second, we explore the different molecular and physical monitoring methods used to measure fluid and electrolyte imbalance and the measurement challenges in diverse populations. Hydration status is assessed in various indices; plasma, sweat, tear, saliva, urine, body mass, interstitial fluid, and skin-integration techniques have been extensively investigated. No unified (de)hydration (fluid and electrolyte imbalance) monitoring technology exists for different populations (including sports, elderly, children, and cancer). Establishing novel methods and technologies to facilitate and unify measurements of hydration status represents an excellent opportunity to develop impactful new approaches for patient care.

Vitamin D Deficiency in Children and Adolescents: Role of Puberty and Obesity on Vitamin D Status

Background:

Vitamin D deficiency is common among children and adolescents and can be affected by several factors such as puberty and obesity.

Objective:

The aim of this study was to evaluate vitamin D status in children and adolescents and to analyse the influence of puberty and obesity on its level.

Method:

A cross-sectional study was carried-out, in which clinical and biochemical data were gathered from 384 healthy children and adolescents between May 2019 to May 2020.

Results:

220 females and 164 males were enrolled (aged 7-16 years; mean ± SD: 11 ± 2.5). Vitamin D deficiency was found in 49% of the total cases and was significantly more prevalent in females than males (33.1% in female; 15.9% in male, P < .001). Mean vitamin D level was lower in obese children compared with non-obese (P < .001). Non-obese group had significantly higher levels of vitamin D in Tanner stage IV of puberty than obese individuals (20.1 ± 17.0 vs 5.4 ± 2.0) (P = .03). Vitamin D levels were significantly lower in females than males only in Tanner stage II (12.3 ± 9.0 vs 19.6 ± 16.6) (P = .005). The lowest level of Vitamin D was in Tanner stage Ⅳ-Ⅴ in boys and in Tanner stage Ⅱ-Ⅲ in girls (P < .001).

Conclusion:

Puberty is an additional risk factor for vitamin D deficiency especially in girls and obese children. This increased risk, together with the fact that most important time for building a proper skeleton is during childhood and adolescent, makes it essential to monitor vitamin D in these age groups.

Centennial Review: Effects of vitamins A, D, E, and C on the chicken immune system

Vitamins are nutritional elements which are necessary for essential activities such as development, growth, and metabolism of cells. In addition to these conventional functions, vitamins A, D, E, and C have vital roles in normal function of the immune system as their deficiency is known to impair innate and adaptive host responses. By altering transcription of multiple immune system genes and contributing to antioxidant activities, these vitamins influence the immune system in different ways including modulation of cell-mediated and antibody-mediated responses, immunoregulation, and antiinflammatory effects. Furthermore, supplementation of these vitamins to poultry may assist the immune system to combat microbial pathogens while reducing detrimental effects associated with stress and enhancing responses to vaccines. In this article, the relationship between the chicken immune system and vitamins A, D, E, and C is reviewed, and evidence from the literature pertaining to how these vitamins exert their antiinflammatory, regulatory, and antimicrobial effects is discussed.

Non-Musculoskeletal Benefits of Vitamin D beyond the Musculoskeletal System

Vitamin D, a fat-soluble prohormone, is endogenously synthesized in response to sunlight or taken from dietary supplements. Since vitamin D receptors are present in most tissues and cells in the body, the mounting understanding of the role of vitamin D in humans indicates that it does not only play an important role in the musculoskeletal system, but has beneficial effects elsewhere as well. This review summarizes the metabolism of vitamin D, the research regarding the possible risk factors leading to vitamin D deficiency, and the relationships between vitamin D deficiency and numerous illnesses, including rickets, osteoporosis and osteomalacia, muscle weakness and falls, autoimmune disorders, infectious diseases, cardiovascular diseases (CVDs), cancers, and neurological disorders. The system-wide effects of vitamin D and the mechanisms of the diseases are also discussed. Although accumulating evidence supports associations of vitamin D deficiency with physical and mental disorders and beneficial effects of vitamin D with health maintenance and disease prevention, there continue to be controversies over the beneficial effects of vitamin D. Thus, more well-designed and statistically powered trials are required to enable the assessment of vitamin D’s role in optimizing health and preventing disease.

Potential role of hypovitaminosis D and vitamin D supplementation during COVID-19 pandemic

Vitamin D deficiency is a pandemic disorder affecting over 1 billion of subjects worldwide and displaying a broad spectrum of implications on cardiovascular and inflammatory disorders. Since the initial reports of the association between hypovitaminosis D and COVID-19, Vitamin D has been pointed as a potentially interesting treatment for SARS-CoV-2 infection. We provide an overview on the current status of vitamin D deficiency, the mechanisms of action of vitamin D and the current literature on the topic, with a special focus on the potential implications for COVID-19 pandemic.

Understanding the Biological Activities of Vitamin D in Type 1 Neurofibromatosis: New Insights into Disease Pathogenesis and Therapeutic Design

Vitamin D is a fat-soluble steroid hormone playing a pivotal role in calcium and phosphate homeostasis as well as in bone health. Vitamin D levels are not exclusively dependent on food intake. Indeed, the endogenous production-occurring in the skin and dependent on sun exposure-contributes to the majority amount of vitamin D present in the body. Since vitamin D receptors (VDRs) are ubiquitous and drive the expression of hundreds of genes, the interest in vitamin D has tremendously grown and its role in different diseases has been extensively studied. Several investigations indicated that vitamin D action extends far beyond bone health and calcium metabolism, showing broad effects on a variety of critical illnesses, including cancer, infections, cardiovascular and autoimmune diseases. Epidemiological studies indicated that low circulating vitamin D levels inversely correlate with cutaneous manifestations and bone abnormalities, clinical hallmarks of neurofibromatosis type 1 (NF1). NF1 is an autosomal dominant tumour predisposition syndrome causing significant pain and morbidity, for which limited treatment options are available. In this context, vitamin D or its analogues have been used to treat both skin and bone lesions in NF1 patients, alone or combined with other therapeutic agents. Here we provide an overview of vitamin D, its characteristic nutritional properties relevant for health benefits and its role in NF1 disorder. We focus on preclinical and clinical studies that demonstrated the clinical correlation between vitamin D status and NF1 disease, thus providing important insights into disease pathogenesis and new opportunities for targeted therapy.

Influence of Single Nucleotide Polymorphisms on Rifampin Pharmacokinetics in Tuberculosis Patients

Rifampin (RF) is metabolized in the liver into an active metabolite 25-desacetylrifampin and excreted almost equally via biliary and renal routes. Various influx and efflux transporters influence RF disposition during hepatic uptake and biliary excretion. Evidence has also shown that Vitamin D deficiency (VDD) and Vitamin D receptor (VDR) polymorphisms are associated with tuberculosis (TB). Hence, genetic polymorphisms of metabolizing enzymes, drug transporters and/or their transcriptional regulators and VDR and its pathway regulators may affect the pharmacokinetics of RF. In this narrative review, we aim to identify literature that has explored the influence of single nucleotide polymorphisms (SNPs) of genes encoding drug transporters and their transcriptional regulators (SLCO1B1, ABCB1, PXR and CAR), metabolizing enzymes (CES1, CES2 and AADAC) and VDR and its pathway regulators (VDR, CYP27B1 and CYP24A1) on plasma RF concentrations in TB patients on antitubercular therapy. Available reports to date have shown that there is a lack of any association of ABCB1, PXR, CAR, CES1 and AADAC genetic variants with plasma concentrations of RF. Further evidence is required from a more comprehensive exploration of the association of SLCO1B1, CES2 and Vitamin D pathway gene variants with RF pharmacokinetics in distinct ethnic groups and a larger population to reach conclusive information.

Patterns of Vitamin D Deficiency in a Community Outpatient Psychiatric Practice: a Real-World Evaluation of Treatment Gaps

Vitamin D is traditionally recognized for its role in bone mineralization but recent observations suggest additional pertinent functions in neuronal biology. The present study examines the rate and pattern of Vitamin D deficiency in the outpatient mental health clinic of a community teaching hospital as well as the vitamin D supplementation practices of outpatient psychiatrists. Participants include 148 consecutive psychiatric outpatients. Individuals with conditions that alter the metabolism of vitamin D were excluded from the study as are those who may be taking medications that influence Vitamin D metabolism. Statistical analysis was performed using the SPSS 25th edition, statistical significance set at p < 0.05. The majority of patients in the study were between 41 and 65 years old (n = 91, 61.5%), African American (n = 120, 81.1%) and female (n = 80, 54.1%). The median level is 23.7 ng/ml. As defined by the Endocrine Society's Clinical Practice Guidelines, 68.2% of the population had insufficient and deficient Vitamin D levels (32.4% and 35.8% respectively), 62.4% of whom were not prescribed any Vitamin D supplementation and of this untreated group, 84% were African Americans. No clinical or demographic characteristics showed any statistical difference in both the "treated" and "not treated groups". Logistic regression did not reveal any significant predictors for Vitamin D deficiency. Vitamin D deficiency remains a significant issue among patients with psychiatric disorders. Our findings show gaps in Vitamin D deficiency treatment and recommend that future studies examine physician prescription practices in light of the racial disparity in Vitamin D deficiency treatment oberved in this study.

Dietary Phytase and Lactic Acid-Treated CerealGrains Differently Affected Calcium and PhosphorusHomeostasis from Intestinal Uptake to SystemicMetabolism in a Pig Model

High intestinal availability of dietary phosphorus (P) may impair calcium (Ca)homeostasis and bone integrity. In the present study, we investigated the effect of phytasesupplementation in comparison to the soaking of cereal grains in 2.5% lactic acid (LA) on intestinalCa and P absorption; intestinal, renal, and bone gene expression regarding Ca and P homeostasis;bone parameters; and serum levels of regulatory hormones in growing pigs. Thirty-two pigs wererandomly assigned to one of four diets in a 2 × 2 factorial design in four replicate batches for 19days. The diets comprised either untreated or LA-treated wheat and maize without and withphytase supplementation (500 phytase units/kg). Although both treatments improved the Pbalance, phytase and LA-treated cereals differently modulated gene expression related to intestinalabsorption, and renal and bone metabolism of Ca and P, thereby altering homeostatic regulatorymechanisms as indicated by serum Ca, P, vitamin D, and fibroblast growth factor 23 levels.Moreover, phytase increased the gene expression related to reabsorption of Ca in the kidney,whereas LA-treated cereals decreased the expression of genes for osteoclastogenesis in bones,indicating an unbalanced systemic availability of minerals. In conclusion, high intestinalavailability of dietary P may impair Ca homeostasis and bone integrity.

In silico identification of novel transcription factors associated with CYP27B1 transcriptional regulation in LPS-challenged mononuclear phagocytes

Renal and extrarenal production of the active form of vitamin D, 1,25-dihydroxyvitamin D (1,25(OH)2D), is catalyzed by CYP27B1, an enzyme also called 1-α-hydroxylase. The overproduction of 1,25(OH)2D has been described in granulomatous diseases. High circulating concentrations of 1,25(OH)2D can lead to hypercalcemia. The aim of this work was to characterize the transcriptional regulation of CYP27B1 in human mononuclear phagocytes exposed to LPS due to its relevance to understanding the hypercalcemia and ectopic calcifications associated with chronic inflammatory diseases such as tuberculosis and other granulomatous diseases. The human CYP27B1 promoter analysis identified binding sites for published TF, SNPs, novel putative TFBS and conserved sites compared to mice. Then, using microarray data, a meta-analysis was performed to obtain a global view of the gene expression in LPS-challenged dendritic cells, monocytes and macrophages. Finally, two experiments, GSE40885 and time series GSE19765, were analyzed in-depth using differential expression analysis which permitted the identification of TF co-expressed with CYP27B1. This work allowed us to formulate a CYP27B1 transcriptional regulation model for LPS-challenged monocytes/macrophages. The importance of two TF families, NFKB and CEBPB, was confirmed. Data also suggests that PLAGL2 and STAT4 which are novel TF could participate in the CYP27B1 transcriptional regulation in cells exposed to LPS. These TF, in turn, would be interacting with regions that present polymorphisms in the general population which might explain the pathological phenotypes associated with altered vitamin D metabolism.

25(OH) D3 alleviate liver NK cytotoxicity in acute but not in chronic fibrosis model of BALB/c mice due to modulations in vitamin D receptor

Background

Low 25-Hydroxy-vitamin-D; “25(OH)-D3” serum and vitamin D receptor (VDR) levels were recently correlated to advanced fibrosis. However, VDR mechanism in liver fibrosis modulations is not well understood. In this study, we aimed to evaluate changes in liver NK cells cytotoxicity due to modulations in VDR in CCl₄ fibrosis model following 25(OH) D3 injections.

Methods

Carbon-tetrachloride (CCl₄) hepatic-fibrosis was induced in BALB/c mice for 1 and 4 weeks as an acute and chronic fibrosis model, respectively. Along 1th to 4th weeks, vitamin D were i.p injected/2x week. Liver were assessed histologically and for proteins quantification for VDR and αSMA expressions. In vitro, potential killing of NK cells were evaluated following co-culture with primary-hepatic-stellate-cells (pHSCs) obtained from BALB/c WT-mice.

Results

Systemic inflammation and hepatic-fibrosis increased along 4 weeks of CCl₄ as indicated by serum ALT and αSMA expressions (P < 0.02) as well as histological assessments, respectively. These results were associated with increased NK1.1 activations and hypercalcemia. While vitamin D administrations delayed fibrosis of early stages, vitamin D worsen hepatic-fibrosis of late stages of CCl₄. In week 4, no further activations of NK cells were seen following vitamin D injections and were associated with down-expressions of VDR (1.7 Fold, P < 0.004) indicating the inability of vitamin D to ameliorate hepatic fibrosis. In vitro, NK cells from the chronic model of CCl₄ did not affect pHSCs killing and fail to reduce fibrosis.

Conclusion

Vitamin D alleviate liver NK cytotoxicity in acute but not in chronic fibrosis model due to modulations in vitamin D receptor and calcium. Hypercalcemia associated with late fibrosis may inhibited VDR levels, however, may not explain the profibrogenic effects of vitamin D.

Bone Metabolism and Vitamin D Implication in Gastroenteropancreatic Neuroendocrine Tumors

Patients affected by gastroenteropancreatic–neuroendocrine tumors (GEP–NETs) have an increased risk of developing osteopenia and osteoporosis, as several factors impact on bone metabolism in these patients. In fact, besides the direct effect of bone metastasis, bone health can be affected by hormone hypersecretion (including serotonin, cortisol, and parathyroid hormone-related protein), specific microRNAs, nutritional status (which in turn could be affected by medical and surgical treatments), and vitamin D deficiency. In patients with multiple endocrine neoplasia type 1 (MEN1), a hereditary syndrome associated with NET occurrence, bone damage may carry other consequences. Osteoporosis may negatively impact on the quality of life of these patients and can increment the cost of medical care since these patients usually live with their disease for a long time. However, recommendations suggesting screening to assess bone health in GEP–NET patients are missing. The aim of this review is to critically analyze evidence on the mechanisms that could have a potential impact on bone health in patients affected by GEP–NET, focusing on vitamin D and its role in GEP–NET, as well as on factors associated with MEN1 that could have an impact on bone homeostasis.

The Relationship Between Thyroid Antibodies and Vitamin D Level in Primary Hypothyroidism

Introduction:

Vitamin D deficiency is a global health problem. Its deficiency has been reported to be associated with different autoimmune diseases.

Aim:

The aim of this study was to evaluate the relationship between vitamin D level and thyroid antibodies in autoimmune hypothyroidism.

Methods:

A total number of 150 individuals were enrolled in this study. They were divided into the fallowing groups: group I included 50 patients with autoimmune thyroid disease (AITD), group II included 50 patients without autoimmune thyroid disease. Group III included 50 apparently healthy participants representing a control group. All participants underwent a detailed clinical examination and laboratory tests including, 25 (OH) vitamin D, thyroid-stimulating hormone (TSH) and thyroid autoantibodies assessment, including anti-thyroid peroxidase antibodies (anti-TPO) and anti-thyroglobulin antibodies (anti-TG).

Results:

Serum levels of 25 (OH) vitamin D recorded a highly significant difference between the studies groups (20,76±6,31 ng/ml in group I vs. 24,37±9,05ng/ml in group II vs. 24,57±6,45ng/ml in group III, p<0,01). Moreover, there was a highly significant difference between patients with AITD and patients without AITD (20,76±6,31ng/ml vs. 24,37±9,05ng/ml, respectively; p<0,01). The concentration of anti-TPO and anti-TG antibodies were statistically significant higher in patients with vitamin D deficiency (p< 0,001). Serum TSH were significantly higher in group I (p< 0,001).

Conclusion:

Significantly low levels of vitamin D were documented in patients with AITD that were related to the presence of anti-thyroid antibodies and higher level thyroid-stimulation hormone (TSH), suggesting the involvement of vitamin D in the pathogenesis of AITD and the advisability of supplementation.

Vitamin D metabolism in dogs and cats and its relation to diseases not associated with bone metabolism

Due to the presence of receptors in the cells of numerous body tissues, vitamin D is associated with several physiological functions that go beyond calcium and phosphorus homoeostasis and control of bone metabolism in the body. In humans, several studies have associated lower vitamin D concentrations with numerous diseases, such as cancer, heart disease, autoimmune diseases and infectious diseases, and also with an increase in the total mortality rate of the population. Recently, this nutrient started to gain importance in veterinary medicine, and several articles have shown a correlation between low vitamin D status and diseases unrelated to bone metabolism. The present review aims to highlight the recent publications that investigated this relationship, bringing the evidence that exists so far in dogs and cats.

The sunshine under our skin: public knowledge and practices about vitamin D deficiency in Al Ain, United Arab Emirates

This cross-sectional study among members of public showed that people generally had good knowledge and awareness about vitamin D. However, inconsistencies between awareness and attitudes were observed. Our findings reinforce the need of educating people to improve attitude and practices toward vitamin D consumption.

INTRODUCTION

Owing to its hot and dry climate, United Arab Emirates (UAE) is one of the top ranked vitamin D deficient countries. However, little is known about people's awareness surrounding this topic.

METHODS

A descriptive cross-sectional survey to assess people's knowledge, awareness, and attitude toward vitamin D deficiency was conducted in Al Ain city of UAE. A 25-item validated self-administered questionnaire was used for data collection. Differences among demographic groups were analyzed using chi-square test, and simple binary logistic regressions were used to investigate the association between vitamin D awareness and other significant risk factors.

RESULTS

More than 90% of the total 346 participants showed awareness toward vitamin D and its deficiency. Doctors were reported as the most common source of information. More than one-third of the participants claimed to have vitamin D deficiency with significantly more females than males. More than 70% of the sample considered sunlight as the best source of vitamin D and avoiding going out in sun as the major risk for vitamin D deficiency. Nearly half (43%) of the participants did not consume milk and only 24% claimed to be using vitamin D supplements. Females were found to be applying sunscreen and consuming vitamin supplements significantly more than their male counterparts. Participants aged 24-35 years, having bachelor degree and those who were tested for vitamin D, were found to score better for awareness questions.

CONCLUSIONS

Our findings demonstrate a mismatch between knowledge and awareness, and attitude implying the need of educating people to improve their attitude toward consuming vitamin D rich food and supplements.

New developments in our understanding of vitamin metabolism, action and treatment

Although vitamin D has been reported to have pleiotropic effects including effects on the immune system and on cancer progression, the principal action of vitamin D is the maintenance of calcium and phosphate homeostasis. The importance of vitamin D in this process is emphasized by the consequences of vitamin D deficiency which includes rickets in children and osteomalacia in adults. Vitamin D deficiency has also been reported to increase the risk of falls and osteoporotic fractures. Although vitamin D fortification of foods (including dairy products) has contributed to a marked decrease in rickets in the Western world, vitamin D deficiency in children and adults is still prevalent world-wide. This review summarizes new developments in our understanding of vitamin D endocrine system and addresses clinical syndromes related to abnormalities in vitamin D metabolism and action. In addition, the current understanding of the evaluation of vitamin D deficiency and sufficiency and recommendations for achieving vitamin D sufficiency are discussed.

Hypovitaminosis D: Is It Time to Consider the Use of Calcifediol?

Hypovitaminosis D is becoming a notable health problem worldwide. A consensus exists among several different medical societies as to the need for adequate levels of vitamin D for bone and general health. The correct method by which to restore normal vitamin D levels is still a matter of debate. Although cholecalciferol remains the most commonly distributed form of vitamin D supplementation worldwide, several drugs with vitamin D activity are available for clinical use, and making the correct selection for the individual patient may be challenging. In this narrative review, we aim to contribute to the current knowledge base on the possible and appropriate use of calcifediol-the 25-alpha-hydroxylated metabolite-in relation to its chemical characteristics, its biological properties, and its pathophysiological aspects. Furthermore, we examine the trials that have aimed to evaluate the effect of calcifediol on the restoration of normal vitamin D levels. Calcifediol is more soluble than cholecalciferol in organic solvents, due to its high polarity. Good intestinal absorption and high affinity for the vitamin-D-binding protein positively affect the bioavailability of calcifediol compared with cholecalciferol. In particular, orally administered calcifediol shows a much shorter half-life than oral cholecalciferol. Most findings suggest that oral calcifediol is about three- to five-fold more powerful than oral cholecalciferol, and that it has a higher rate of intestinal absorption. Accordingly, calcifediol can be particularly useful in treating diseases associated with decreased intestinal absorption, as well as obesity (given its lower trapping in the adipose tissue) and potentially neurological diseases treated with drugs that interfere with the hepatic cytochrome P-450 enzyme system, resulting in decreased synthesis of calcifediol. Up to now, there has not been enough clinical evidence for its use in the context of osteoporosis treatment.

Quantitation of serum 25(OH)D2 and 25(OH)D3 concentrations by liquid chromatography tandem mass spectrometry in patients with diabetes mellitus

Vitamin D has been considered to regulate calcium and phosphorus homeostasis and to preserve skeletal integrity. Serum 25-hydroxyvitamin D (25(OH)D) is the best indicator of vitamin D levels. The association of serum 25(OH)D deficiency with increased risk of type 1 diabetes (T1DM) and type 2 diabetes (T2DM) is controversial. We investigated serum 25(OH) D₂ and 25(OH)D₃ levels in diabetes patients by using liquid chromatography tandem mass spectrometry (LC-MS/MS). Serum 25(OH)D2 and 25(OH)D3 levels were measured with liquid chromatography tandem mass spectrometry in electrospray ionization positive mode. Chromatograms were separated using an ACE5 C18 column on a gradient of methanol. The total 25(OH)D levels were calculated as the sum of 25(OH)D3 and 25(OH)D2 levels. A total of 56 patients with T1DM and 41 patients with T2DM were enrolled in this study. There were 42 and 28 non-diabetic, age-matched volunteers who participated as the T1DM controls and the T2DM controls, respectively. The total 25(OH)D levels were lowest in the 21–40 age group. The levels of both 25(OH)D3 and the total 25(OH)D were significantly higher in the T1DM and T2DM groups than in the controls (p < 0.01 in T1DM and p < 0.05 in T2DM group, respectively). The 25(OH)D2 levels were only significantly higher in T1DM patients than in the controls. The percentages of vitamin D deficiency (total 25(OH)D less than 20 ng/mL) in the T1DM, T2DM, the T1DM controls and the T2DM controls were 7.1%, 0%, 14.3% and 3.6%, respectively. The percentages of vitamin D insufficiency (total 25(OH)D less than 30 ng/mL) in the T1DM, T2DM, the T1DM controls and the T2DM controls were 26.8%, 7.3%, 54.8% and 17.9%, respectively. The percentages of vitamin D deficiency and insufficiency were significantly lower in the T1DM patients than in the T1DM controls (p < 0.01). In the present study, both type 1 and type 2 diabetes patients had higher serum 25(OH)D levels and lower percentages of vitamin D deficiency/insufficiency.

Linkage of microbiota and osteoporosis: A mini literature review

The gut microbiota (GM) has become a recent topic of interest in the role of many disease states. Assessing patients with osteoporosis (OP), there is a strong correlation between gut microbe dysregulation and decreased bone density. Gut dysbiosis may lead to inflammation, dysregulation of nutrient and calcium transport across the intestine into circulation and systemic inflammation. Investigation of microbial profile relative to normal gut microbiomes, assessment of inflammatory markers such as interleukin-1 (IL-1), IL-6, and tumor necrosis factor-alpha. Therapies to normalize GM in patients with OP or prevent occurrence of OP to be investigated include: High fiber prebiotic diets to promote growth of normal gut bacteria and short chain fatty acid production, Probiotics to encourage growth of normal gut microbes, and antibiotic treatment followed by fecal matter transplant.

The effect of vitamin D pathway genes and deferasirox pharmacogenetics on liver iron in thalassaemia major patients

Monitoring and treating iron overload is crucial in transfusion-dependent thalassaemia patients. Liver stiffness measurement by transient elastography and T2* magnetic resonance imaging represent non-invasive ways to evaluate the adequacy of the iron chelation treatment. We explored the role of single nucleotide polymorphisms involved in vitamin D metabolism, transport and activity, and in deferasirox metabolism on liver iron burden parameters. One-hundred and five beta-thalassaemia patients, treated with deferasirox, have been enrolled. Drug plasma C_trough and AUC were measured by a HPLC-UV method. Allelic discrimination was performed by real-time PCR. Age, UGT1A1-364 CT/TT and CYP27B1 -1260 GT/TT positively predicted liver stiffness values. Deferasirox dose and serum ferritin negatively predicted T2* data, whereas age and CYP2D6 1457 GG genotype positively influenced these values. The discoveries of this research may be useful for personalized medicine and the proposed method could be applied in patients with hereditary hemochromatosis and myelodysplastic syndromes.

Association of Vitamin D Status with Chronic Disease Risk Factors and Cognitive Dysfunction in 50⁻70 Year Old Adults

Vitamin D deficiency/insufficiency has been primarily associated with skeletal disorders, however, since vitamin D receptors are found on multiple types of cells, there is also a link to increased chronic disease risk and all-cause mortality. The aim of this study was to examine whether deficient/insufficient vitamin D levels are associated with risk factors of chronic diseases and cognitive dysfunction in 50 to 70 year old adults. Participants completed the health status, three-day dietary record and vitamin D food frequency, sun exposure, and international physical activity questionnaires. Cognitive function of the participants was assessed using the Automated Neuropsychological Assessment Metrics while body composition (percent body fat, android/gynoid ratio) was assessed using Dual Energy X-ray Absorptiometry. Applanation tonometry was used to obtain pressure wave forms at the radial artery to examine arterial stiffness and central pressures. A fasting blood draw was taken to measure vitamin D, blood lipid and glucose levels. Fifty percent of the participants (36/72) were vitamin D deficient/insufficient. Individuals in the low physical activity (PA) group had lower serum vitamin D concentration compared to those in the high PA group (p = 0.04). Moreover, serum vitamin D levels were negatively related to risk factors of chronic diseases; blood glucose (r = -0.38; p = 0.01), triglycerides (r = -0.27; p = 0.02), and android/gynoid ratio (r = -0.32; p = 0.01). Deficient/insufficient vitamin D levels are linked to the risk factors of chronic diseases in men and women aged 50 to 70 years.