Vitamin D and diabetes

Receptors and Signaling Pathways Controlling Beta-Cell Function and Survival as Targets for Anti-Diabetic Therapeutic Strategies

Preserving the function and survival of pancreatic beta-cells, in order to achieve long-term glycemic control and prevent complications, is an essential feature for an innovative drug to have clinical value in the treatment of diabetes. Innovative research is developing therapeutic strategies to prevent pathogenic mechanisms and protect beta-cells from the deleterious effects of inflammation and/or chronic hyperglycemia over time. A better understanding of receptors and signaling pathways, and of how they interact with each other in beta-cells, remains crucial and is a prerequisite for any strategy to develop therapeutic tools aimed at modulating beta-cell function and/or mass. Here, we present a comprehensive review of our knowledge on membrane and intracellular receptors and signaling pathways as targets of interest to protect beta-cells from dysfunction and apoptotic death, which opens or could open the way to the development of innovative therapies for diabetes.

Type 1 diabetes mellitus and sperm quality: A case-control study

BACKGROUND

The potential impact of diabetes mellitus type 1 (DM1) on male fertility is currently poorly defined. Hyperglycaemia and insulin deficiency may affect spermatogenesis. Some evidence suggests that men with DM1 have a significant reduction in progressive sperm motility, sperm morphology and semen volume, without significant changes in sperm concentration and count, but definite data are lacking.

OBJECTIVES

To evaluate the impact of DM1 on clinical parameters related to male fertility and semen analysis.

MATERIALS AND METHODS

We compared a court of 42 male DM1 patients with 43 nondiabetic subjects overlapping in age and remaining clinical data in an observational case-control study. All subjects underwent a comprehensive andrological reproductive evaluation, including medical history, physical examination, and semen analysis. We collected biochemical data in all patients with DM1, while diabetic patients with any alteration in semen parameters underwent sperm culture and scrotal ultrasound. In addition, all men completed the IIEF-5 questionnaire (International Index of Erectile Function-5) and the AMS (Aging Male Symptom score) questionnaire.

RESULTS

Patients with DM1 had a higher prevalence of infertility, erectile dysfunction and worse semen parameters compared with controls. In particular, semen volume, total sperm count, and total and progressive sperm motility were significantly lower (p < 0.001, p = 0.003, p = 0.048, and p = 0.022 respectively). In addition, the rate of semen anti-sperm antibody positivity, the AMS score and FSH levels were higher.

DISCUSSION AND CONCLUSION

Several mechanisms may contribute to these semen alterations in DM1 patients, such as oxidative damage to spermatogenesis, seminal infections and pelvic neurological changes. These data suggest that patients with DM1 should be counselled from an andrological-reproductive point of view.

Forgetting the Frail: National Trends in Vitamin D Prescription After Fragility Fracture-A Large Insurance Claims Database Study

INTRODUCTION

Vitamin D plays a critical role in bone health, affecting bone mineral density and fracture healing. Insufficient serum vitamin D levels are associated with increased fracture rates. Despite guidelines advocating vitamin D supplementation, little is known about the prescription rates after fragility fractures. This study aims to characterize vitamin D prescription rates after three common fragility fractures in patients older than 50 years and explore potential factors influencing prescription rates.

METHODS

The study used the PearlDiver Database, identifying patients older than 50 years with hip fractures, spinal compression fractures, or distal radius fractures between 2010 and 2020. Patient demographics, comorbidities, and vitamin D prescription rates were analyzed. Statistical methods included chi-square analysis and univariate and multivariable analyses.

RESULTS

A total of 3,214,294 patients with fragility fractures were included. Vitamin D prescriptions increased from 2.50% to nearly 6% for all fracture types from 2010 to 2020. Regional variations existed, with the Midwest having the highest prescription rate (4.25%) and the West the lowest (3.31%). Patients with comorbidities such as diabetes, tobacco use, obesity, female sex, age older than 60 years, and osteoporosis were more likely to receive vitamin D prescriptions.

DISCUSSION

Despite a notable increase in vitamin D prescriptions after fragility fractures, the absolute rates remain low. Patient comorbidities influenced prescription rates, perhaps indicating growing awareness of the link between vitamin D deficiency and these conditions. However, individuals older than 60 years, a high-risk group, were markedly less likely to receive prescriptions, possibly because of practice variations and concerns about polypharmacy. Educational initiatives and revised guidelines may have improved vitamin D prescription rates after fragility fractures. However, there is a need to raise awareness about the importance of vitamin D for bone health, particularly in older adults, and additional study variations in prescription practices. These findings emphasize the importance of enhancing post-fracture care to reduce morbidity and mortality associated with fragility fractures.

LEVEL OF EVIDENCE

III.

Molecular effects of Vitamin-D and PUFAs metabolism in skeletal muscle combating Type-II diabetes mellitus

Multiple post-receptor intracellular alterations such as impaired glucose transfer, glucose phosphorylation, decreased glucose oxidation, and glycogen production contribute to insulin resistance (IR) in skeletal muscle, manifested by diminished insulin-stimulated glucose uptake. Type-2 diabetes mellites (T2DM) has caused by IR, which is also seen in obese patients and those with metabolic syndrome. The Vitamin-D receptor (VDR) and poly unsaturated fatty acids (PUFAs) roles in skeletal muscle growth, shapes, and function for combating type-2 diabetes have been clarified throughout this research. VDR and PUFAs appears to show a variety of effects on skeletal muscle, in addition it shows a promising role on bone and mineral homeostasis. Individuals having T2DM are reported to suffer from severe muscular weakness and alterations in shape of the muscle. Several studies have investigated the effect on VDR on muscular strength and mass, which leads to Vitamin-D deficiency (VDD) in individuals, in which most commonly seen in elderly. VDR has been shown to affect skeletal cellular proliferation, intracellular calcium handling, as well as genomic activity in a variety of different ways such as muscle metabolism, insulin sensitivity, which is the major characteristic pathogenesis for IR in combating T2DM. The identified VDR gene polymorphisms are ApaI, TaqI, FokI, and BsmI that are associated with T2DM. This review collates informations on the mechanisms by which VDR activation takes place in skeletal muscles. Despite the significant breakthroughs made in recent decades, various studies show that IR affects VDR and PUFAs metabolism in skeletal muscle. Therefore, this review collates the data to show the role of VDR and PUFAs in the skeletal muscles to combat T2DM.

Association of vitamin D and cognition in people with type 2 diabetes: a systematic review

CONTEXT

There is a high prevalence of vitamin D deficiency and impaired cognitive function in people with type 2 diabetes mellitus (T2DM).

OBJECTIVE

To critically and systematically review the literature on the association between vitamin D status and cognitive performance in people with type 2 diabetes.

DATA SOURCES

This review was conducted according to PRISMA recommendations. MEDLINE, SCOPUS, the Cochrane Library, and Web of Science databases were searched using the terms "Diabetes Mellitus, Type 2", "Cognitive Function", and "Vitamin D".

DATA EXTRACTION

Eight observational and 1 randomized study were included, containing data of 14 648 adult and elderly individuals (19-74 y). All extracted data were compiled, compared, and critically analyzed.

DATA ANALYSIS

There is no strong evidence that lower serum concentrations of vitamin D and vitamin D-binding protein are associated with worsening cognitive function in individuals with T2DM. Vitamin D supplementation (12 wk) improved the scores of some executive functioning tests, although there was no difference between low doses (5000 IU/wk) and high doses (50 000 IU/wk).

CONCLUSIONS

There is no high-quality evidence demonstrating an association between vitamin D status and cognitive function, or clinical benefits on cognition from vitamin D supplementation in individuals with T2DM. Future studies are needed. Systematic Review Registration: PROSPERO registration no. CRD42021261520.

The Association between Serum 25-Hydroxyvitamin D3 Levels and Pro-Inflammatory Markers in New-Onset Type 2 Diabetes Mellitus and Prediabetes

In this study, we aimed to reveal the pro-inflammatory effects of serum 25-hydroxyvitamin D3 (Vit D) deficiency and insufficiency in new-onset type 2 diabetes mellitus (T2DM) and prediabetes. We recruited 84 prediabetes patients, 94 new-onset T2DM patients and 113 healthy participants. We measured the levels of C-reactive protein (CRP), fibrinogen, ferritin, interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), nuclear factor kappa-B (NF-κB) and mitogen-activated protein kinase (MAPK) in the serum of the participants. ANOVA Bonferroni and Kruskal-Wallis Dunn tests were used to compare the inflammation markers and vitamin D levels between the groups. Based on covariance analysis with age, gender and BMI, the Vit D levels of the T2DM group were significantly lower (p < 0.003). Pro-inflammatory markers and CRP were significantly higher in prediabetic and diabetic subjects. In the prediabetes group, IL-1β, IL-6, IL-8, TNF-α and MAPK were significantly higher in those with Vit D insufficiency and deficiency groups. In the T2DM group, IL-1β, IL-6, IL-8, TNF-α, NF-κB, MAPK and CRP were significantly higher in those with Vit D insufficiency and deficiency. Our study emphasizes the pro-inflammatory effects of Vit D deficiency and insufficiency in new-onset type 2 diabetes mellitus and prediabetes.

Prospective effects of cholecalciferol supplementation on irisin levels in sedentary postmenopausal women: A pilot study

Introduction

In postmenopausal women, vitamin D deficiency has been associated with disability, low muscle mass and fractures. Irisin is an important myokine that may contribute to the maintenance of muscle and bone density. Vitamin D is associated with the growth and function of muscle tissue through interactions between the vitamin D receptor and PGC-1α and activation of p38/MAPK (mitogen-activated protein kinase) in muscle, a mechanism similar to irisin action. The aim of this pilot study was to evaluate the effects of cholecalciferol supplementation on serum irisin levels in sedentary postmenopausal women with hypovitaminosis D (25(OH)D < 20 ng/mL).

Material and methods

80 sedentary postmenopausal women with hypovitaminosis D and low sun exposure were supplemented with cholecalciferol (30,000 IU/month) for 12 months. Calcium, parathyroid hormone, alkaline phosphatase (AP) and irisin levels were measured before and after supplementation.

Results

25(OH) vitamin D increased in all participants. Serum levels of irisin increased (from 0.52 ± 0.27 to 0.80 ± 0.53; p < 0.003), accompanied by a decrease in AP (from 80 ± 24 to 66 ± 23; p < 0.001).

Conclusions

Restoration of vitamin D status increased serum irisin levels in sedentary postmenopausal women. Whether increased serum irisin levels may have an impact on clinical outcomes deserves further evaluation.

The Role of Vitamin D and Its Molecular Bases in Insulin Resistance, Diabetes, Metabolic Syndrome, and Cardiovascular Disease: State of the Art

In the last decade, an increasing awareness was directed to the role of Vitamin D in non-skeletal and preventive roles for chronic diseases. Vitamin D is an essential hormone in regulating calcium/phosphorous balance and in the pathogenesis of inflammation, insulin resistance, and obesity. The main forms of vitamin D, Cholecalciferol (Vitamin D3) and Ergocalciferol (Vitamin D2) are converted into the active form (1,25-dihydroxyvitamin D) thanks to two hydroxylations in the liver, kidney, pancreas, and immune cells. Some anti-inflammatory cytokines are produced at higher levels by vitamin D, while some pro-inflammatory cytokines are released at lower levels. Toll-Like Receptor (TLR) expression is increased, and a pro-inflammatory state is also linked to low levels of vitamin D. Regardless of how it affects inflammation, various pathways suggest that vitamin D directly improves insulin sensitivity and secretion. The level of vitamin D in the body may change the ratio of pro- to anti-inflammatory cytokines, which would impact insulin action, lipid metabolism, and the development and function of adipose tissue. Many studies have demonstrated an inverse relationship between vitamin D concentrations and pro-inflammatory markers, insulin resistance, glucose intolerance, metabolic syndrome, obesity, and cardiovascular disease. It is interesting to note that several long-term studies also revealed an inverse correlation between vitamin D levels and the occurrence of diabetes mellitus. Vitamin D supplementation in people has controversial effects. While some studies demonstrated improvements in insulin sensitivity, glucose, and lipid metabolism, others revealed no significant effect on glycemic homeostasis and inflammation. This review aims to provide insight into the molecular basis of the relationship between vitamin D, insulin resistance, metabolic syndrome, type 1 and 2 diabetes, gestational diabetes, and cardiovascular diseases.

Single-cell chromatin accessibility of developing murine pancreas identifies cell state-specific gene regulatory programs

Numerous studies have characterized the existence of cell subtypes, along with their corresponding transcriptional profiles, within the developing mouse pancreas. The upstream mechanisms that initiate and maintain gene expression programs across cell states, however, remain largely unknown. Here, we generate single-nucleus ATAC-Sequencing data of developing murine pancreas and perform an integrated, multi-omic analysis of both chromatin accessibility and RNA expression to describe the chromatin landscape of the developing pancreas at both E14.5 and E17.5 at single-cell resolution. We identify candidate transcription factors regulating cell fate and construct gene regulatory networks of active transcription factor binding to regulatory regions of downstream target genes. This work serves as a valuable resource for the field of pancreatic biology in general and contributes to our understanding of lineage plasticity among endocrine cell types. In addition, these data identify which epigenetic states should be represented in the differentiation of stem cells to the pancreatic beta cell fate to best recapitulate in vitro the gene regulatory networks that are critical for progression along the beta cell lineage in vivo.

Three Major Causes of Metabolic Retinal Degenerations and Three Ways to Avoid Them

An imbalance of homeostasis in the retina leads to neuron loss and this eventually results in a deterioration of vision. If the stress threshold is exceeded, different protective/survival mechanisms are activated. Numerous key molecular actors contribute to prevalent metabolically induced retinal diseases-the three major challenges are age-related alterations, diabetic retinopathy and glaucoma. These diseases have complex dysregulation of glucose-, lipid-, amino acid or purine metabolism. In this review, we summarize current knowledge on possible ways of preventing or circumventing retinal degeneration by available methods. We intend to provide a unified background, common prevention and treatment rationale for these disorders and identify the mechanisms through which these actions protect the retina. We suggest a role for herbal medicines, internal neuroprotective substances and synthetic drugs targeting four processes: parainflammation and/or glial cell activation, ischemia and related reactive oxygen species and vascular endothelial growth factor accumulation, apoptosis and/or autophagy of nerve cells and an elevation of ocular perfusion pressure and/or intraocular pressure. We conclude that in order to achieve substantial preventive or therapeutic effects, at least two of the mentioned pathways should be targeted synergistically. A repositioning of some drugs is considered to use them for the cure of the other related conditions.

The Role of Vitamin D in Health and Disease: A Narrative Review on the Mechanisms Linking Vitamin D with Disease and the Effects of Supplementation

Vitamin D insufficiency or deficiency (VDD) is a very prevalent condition in the general population. Vitamin D is necessary for optimal bone mineralization, but apart from the bone effects, preclinical and observational studies have suggested that vitamin D may have pleiotropic actions, whereas VDD has been linked to several diseases and higher all-cause mortality. Thus, supplementing vitamin D has been considered a safe and inexpensive approach to generate better health outcomes-and especially so in frail populations. Whereas it is generally accepted that prescribing of vitamin D in VDD subjects has demonstrable health benefits, most randomized clinical trials, although with design constraints, assessing the effects of vitamin D supplementation on a variety of diseases have failed to demonstrate any positive effects of vitamin D supplementation. In this narrative review, we first describe mechanisms through which vitamin D may exert an important role in the pathophysiology of the discussed disorder, and then provide studies that have addressed the impact of VDD and of vitamin D supplementation on each disorder, focusing especially on randomized clinical trials and meta-analyses. Despite there already being vast literature on the pleiotropic actions of vitamin D, future research approaches that consider and circumvent the inherent difficulties in studying the effects of vitamin D supplementation on health outcomes are needed to assess the potential beneficial effects of vitamin D. The evaluation of the whole vitamin D endocrine system, rather than only of 25-hydroxyvitamin D levels before and after treatment, use of adequate and physiologic vitamin D dosing, grouping based on the achieved vitamin D levels rather than the amount of vitamin D supplementation subjects may receive, and sufficiently long follow-up are some of the aspects that need to be carefully considered in future studies.

The Association Between Insulin Use and Asthma: An Epidemiological Observational Analysis and Mendelian Randomization Study

BACKGROUND

Asthma is a common respiratory disease caused by genetic and environmental factors, but the contribution of insulin use to the risk of asthma remains unclear. This study aimed to investigate the association between insulin use and asthma in a large population-based cohort, and further explore their causal relationship by Mendelian randomization (MR) analysis.

METHODS

An epidemiological study including 85,887 participants from the National Health and Nutrition Examination Survey (NHANES) 2001-2018 was performed to evaluate the association between insulin use and asthma. Based on the inverse-variance weighted approach, MR analysis were conducted to estimate the causal effect of insulin use on asthma from the UKB and FinnGen datasets, respectively.

RESULTS

In the NHANES cohort, we found that insulin use was associated with an increased risk of asthma [odd ratio (OR) 1.38; 95% CI 1.16-1.64; p < 0.001]. For the MR analysis, we found a causal relationship between insulin use and a higher risk of asthma in both Finn (OR 1.10; p < 0.001) and UK Biobank cohorts (OR 1.18; p < 0.001). Meanwhile, there was no causal association between diabetes and asthma. After multivariable adjustment for diabetes in UKB cohort, the insulin use remained significantly associated with an increased risk of asthma (OR 1.17, p < 0.001).

CONCLUSIONS

An association between insulin use and an increased risk of asthma was found via the real-world data from the NHANES. In addition, the current study identified a causal effect and provided a genetic evidence of insulin use and asthma. More studies are needed to elucidate the mechanisms underlying the association between insulin use and asthma.

Pharmacological inhibitors of β-cell dysfunction and death as therapeutics for diabetes

More than 500 million adults suffer from diabetes worldwide, and this number is constantly increasing. Diabetes causes 5 million deaths per year and huge healthcare costs per year. β-cell death is the major cause of type 1 diabetes. β-cell secretory dysfunction plays a key role in the development of type 2 diabetes. A loss of β-cell mass due to apoptotic death has also been proposed as critical for the pathogenesis of type 2 diabetes. Death of β-cells is caused by multiple factors including pro-inflammatory cytokines, chronic hyperglycemia (glucotoxicity), certain fatty acids at high concentrations (lipotoxicity), reactive oxygen species, endoplasmic reticulum stress, and islet amyloid deposits. Unfortunately, none of the currently available antidiabetic drugs favor the maintenance of endogenous β-cell functional mass, indicating an unmet medical need. Here, we comprehensively review over the last ten years the investigation and identification of molecules of pharmacological interest for protecting β-cells against dysfunction and apoptotic death which could pave the way for the development of innovative therapies for diabetes.

Association of vitamin D and magnesium with insulin sensitivity and their influence on glycemic control

Insulin resistance increases the risk of developing diabetes, and the degree of resistance influences the glycemic control of patients with diabetes. Numerous researchers have focused on improving insulin sensitivity in order to prevent diabetes-related complications and other chronic diseases. Several studies have also linked vitamin D levels to insulin secretion and resistance, given that both vitamin D and its receptor complex play important roles in regulating pancreatic β-cells. It has been suggested that vitamin D supplementation improves vitamin D levels, but further research is needed to confirm this as neither insulin function nor glycemic control improves when vitamin D levels increase. Magnesium is a cofactor for many enzymes. Although the role of magnesium in the management of diabetes has long been evaluated, it has not yet been determined whether magnesium supplements improve insulin function. However, several researchers have found that patients with good glycemic control have high magnesium levels. Magnesium is closely related to vitamin D and is necessary for the transport and activation of vitamin D in humans. Combined supplementation with vitamin D and magnesium improves glycemic control in patients with diabetes.

Vitamin D regulates insulin and ameliorates apoptosis and oxidative stress in pancreatic tissues of rats with streptozotocin-induced diabetes

This study was designed to evaluate the potential therapeutic efficacy of vitamin D (Vit D) in averting the harmful effects of type 2 diabetes mellitus (T2D). Forty male Wistar rats were allotted into four groups: (1) the control, (2) Vit D, (3) streptozotocin (STZ), and (4) STZ + Vit D groups. Rats co-treated with Vit D had significantly (p < 0.05) decreased levels of cortisol; proinflammatory cytokines, including interleukin-6 (IL-6); and malondialdehyde (MDA). Meanwhile, the levels of insulin significantly (p < 0.05) increased, whereas the activity of the antioxidant system, including glutathione (GSH), superoxide dismutase (SOD), catalase, and total antioxidant capacity (TAC), significantly (p < 0.05) decreased. Histopathological examination revealed the destruction of beta cells in the islets of Langerhans in rats with diabetes. Meanwhile, immunoexpression revealed an increase in the immunoreactivity of caspase-3 and endothelial nitric oxide synthase and a reduction in the immunoreactivity of insulin in rats with diabetes. In conclusion, Vit D ameliorated the harmful biochemical impact of diabetes mellitus, probably by increasing insulin secretion and sensitivity, ameliorating β-cell function, and decreasing cortisol levels; also, the anti-inflammatory effect of Vit D reduces the number of proinflammatory cytokines (e.g., IL-6) and increases the activity of the antioxidant system, such as GSH, SOD, TAC, and catalase while reducing lipid peroxidation enzymes (e.g., MDA).

Vitamin D and Beta Cells in Type 1 Diabetes: A Systematic Review

The prevalence of type 1 diabetes (T1D) is rising steadily. A potential contributor to the rise is vitamin D. In this systematic review, we examined the literature around vitamin D and T1D. We identified 22 papers examining the role of vitamin D in cultured β-cell lines, islets, or perfused pancreas, and 28 papers examining vitamin D in humans or human islets. The literature reports strong associations between T1D and low circulating vitamin D. There is also high-level (systematic reviews, meta-analyses) evidence that adequate vitamin D status in early life reduces T1D risk. Several animal studies, particularly in NOD mice, show harm from D-deficiency and benefit in most studies from vitamin D treatment/supplementation. Short-term streptozotocin studies show a β-cell survival effect with supplementation. Human studies report associations between VDR polymorphisms and T1D risk and β-cell function, as assessed by C-peptide. In view of those outcomes, the variable results in human trials are generally disappointing. Most studies using 1,25D, the active form of vitamin D were ineffective. Similarly, studies using other forms of vitamin D were predominantly ineffective. However, it is interesting to note that all but one of the studies testing 25D reported benefit. Together, this suggests that maintenance of optimal circulating 25D levels may reduce the risk of T1D and that it may have potential for benefits in delaying the development of absolute or near-absolute C-peptide deficiency. Given the near-complete loss of β-cells by the time of clinical diagnosis, vitamin D is much less likely to be useful after disease-onset. However, given the very low toxicity of 25D, and the known benefits of preservation of C-peptide positivity for long-term complications risk, we recommend considering daily cholecalciferol supplementation in people with T1D and people at high risk of T1D, especially if they have vitamin D insufficiency.

Association between serum 25 (OH) D levels and depression symptoms in adults with prediabetes

BACKGROUND AND AIM

Depression symptoms are a significant risk factor for prediabetes-related diabetes, and low vitamin D levels are connected with depression symptoms. The goal of this study is to examine the association between vitamin D and depression symptoms in prediabetic persons.

METHODS

This cross-sectional survey was conducted in Tianjin, China, among 4051 individuals. Symptoms of depression were assessed using the Self-Rating Depression Scale (SDS) (cut-off point SDS ≥45). Serum 25 (OH) D concentrations were determined using an enzyme immunoassay (OCTEIA 25-hydroxy Vitamin D, IDS Ltd, UK) and classified into three levels: 50 nmol/L, 50-75 nmol/L, and >75 nmol/L. The link between serum 25 (OH) D concentrations and depression symptoms in prediabetes was investigated using multiple logistic regression analysis. The models were adjusted for a variety of potential confounders.

RESULTS

The prevalence of symptoms of depression in prediabetic adults was 14.2% (12.5% males and 16.4% females). After adjusting for potentially confounding variables, the odds ratios - ORs for symptoms of depression in women across serum 25 (OH) D levels were 1.00 (reference), 1.03 (0.57, 1.39), and 0.28 (0.12, 0.57), respectively (p = 0.0015). However, no statistically significant connection was discovered in males.

CONCLUSION

In women with prediabetes, we showed a substantial negative connection between serum 25 (OH) D levels and depressed symptoms. Vitamin D supplementation may be an effective way to decrease the risk of depression symptoms in women with prediabetes.

Vitamin D Deficiency During the First Trimester of Pregnancy and the Risk of Developing Gestational Diabetes Mellitus

OBJECTIVE

To investigate the relationships among various factors that affect serum vitamin D levels and vitamin D in the first trimester and the risk of developing gestational diabetes mellitus (GDM).

DESIGN

A prospective cohort design.

SETTING

The family health center of Ankara, Turkey.

PARTICIPANTS

Out of 889 pregnant women who participated in the study in the first trimester (6-13 weeks gestation), 814 participated in GDM screening in the second trimester (24-28 weeks gestation).

METHODS

We determined serum vitamin D levels, demographic data, various biochemical and anthropometric parameters, and factors that affect vitamin D synthesis of participants in the first trimester and used logistic regression analysis to analyze the effects of the associations among vitamin D deficiency and the other variables on the occurrence of GDM.

RESULTS

Vitamin D deficiency in the first trimester was present in 425 (82.5%) participants. In the second trimester, 198 participants (24.3%) were diagnosed with GDM through oral glucose tolerance test screening. We detected GDM in the second trimester in 5.7% of participants who had vitamin D deficiency in the first trimester. Even after adjustment for vitamin D intake, clothing style, and duration of exposure to the sun, the risk of GDM was significantly greater in participants who were vitamin D deficient than those who were not deficient. The risk of GDM among women with vitamin D deficiency was sustained or increased significantly after we adjusted for age, parity, prepregnancy body mass index, history of diabetes, triglyceride levels, vitamin D intake, clothing style, and length of sun exposure, OR = 10.60, p < .001, 95% confidence interval [2.82, 39.76].

CONCLUSIONS

Our results suggest that vitamin D deficiency in the first trimester may significantly increase the risk of developing GDM.

Association between vitamin D and insulin resistance in adults with latent tuberculosis infection: Results from the National Health and Nutrition Examination Survey (NHANES) 2011-2012

BACKGROUND

Evidence demonstrated that vitamin D insufficiency was involved in insulin resistance (IR) pathogenesis and associated with tuberculosis. However, the association of vitamin D and IR in patients with latent tuberculosis infection (LTBI) remains unclear. This study aims to evaluate the association between vitamin D and insulin resistance in US adults with LTBI.

METHOD

National Health and Nutrition Examination Survey (NHANES) participants ≥ 20 years during the years 2011-2012 with positive QuantiFERON®-TB Gold-In-Tube (QFT) or tuberculin skin testing (TST) were enrolled in present study. Participants with LTBI were divided into 2 groups: (1) vitamin D insufficiency group (n = 267), and (2) vitamin D sufficiency group (n = 437).

RESULTS

Weighted analysis of all the population in the study showed that serum 25(OH)D inversely correlated with HOMA-IR (r = -0.14, P = 0.008). The vitamin D insufficiency group had higher fasting insulin (17.5 (1.38) vs. 15.29 (3.1), respectively, P = 0.0013) and HOMA-IR (5.0 (0.4) vs. 4.5 (1), respectively, P = 0.013) than the vitamin D sufficiency group. In adjusted analysis, vitamin D levels was independently associated with insulin resistance (adjusted OR [aOR] 2.74; 95% CI, 1.01-7.48, p = 0.0489).

CONCLUSIONS

Taken together, our study suggested that serum 25(OH) D concentrations were inversely and independently associated with HOMA-IR in LTBI.

Combined resveratrol and vitamin D treatment ameliorate inflammation-related liver fibrosis, ER stress, and apoptosis in a high-fructose diet/streptozotocin-induced T2DM model

A high fructose diet is a major cause of diabetes and various metabolic disorders, including fatty liver. In this study, we investigated the effects of resveratrol and vitamin D (VitD) treatments on endoplasmic reticulum (ER) stress, oxidative stress, inflammation, apoptosis, and liver regeneration in a rat model of type 2 diabetes mellitus, namely, T2DM Sprague-Dawley rats. This T2DM rat model was created through a combination treatment of a 10% fructose diet and 40 mg/kg streptozotocin (STZ). Resveratrol (1 mg/kg/day) and VitD (170/IU/week) were administered alone and in combination to both the diabetic and control groups. Immunohistochemical staining was performed to evaluate PCNA, NF-κB, TNF-α, IL-6, IL-1β, GRP78, and active caspase-3 in liver tissue. The TUNEL method and Sirius red staining were used to determine apoptosis and fibrosis, respectively. G6PD, 6-PGD, GR, and GST activities were measured to determine oxidative stress status. We found that the expressions of cytokines (TNF-α, IL-6, and IL-1β) correlated with NF-κB activation and were significantly increased in the T2DM rats. Increased GRP78 expression, indicating ER stress, increased in apoptotic cells, enhanced caspase-3 activation, and collagen accumulation surrounding the central vein were observed in the T2DM group compared with the other groups. The combination VitD + resveratrol treatment improved antioxidant defense via increasing G6PD, 6-PGD, GR, and GST activities compared to the diabetic groups. We concluded that the combined administration of resveratrol with VitD ameliorates the adverse effects of T2DM by regulating blood glucose levels, increasing antioxidant defense mechanisms, controlling ER stress, enhancing tissue regeneration, improving inflammation, and reducing apoptosis in liver cells. In conclusion, this study indicates that the combination treatment of resveratrol + VitD can be a beneficial option for preventing liver damage in fructose-induced T2DM.

Analysis of risk factors for the development of type 2 diabetes mellitus complicated with Hashimoto's thyroiditis

AIMS

The purpose of this study is to elucidate the correlation between thyroid hormone, glycosylated hemoglobin (HbA1c), vitamin D and type 2 diabetes mellitus (T2DM) with Hashimoto's thyroiditis (HT), and to seek the independent predictors affecting disease development.

METHODS

The study included 44 T2DM with HT, 94 T2DM, and 112 healthy subjects. We investigated some laboratory factors like thyroid hormone and compared the levels. Independent predictors determination by logistic univariate regression analysis were analyzed. The diagnostic value of thyroid-stimulating hormone (TSH) and threshold concentration were determined by ROC curve.

RESULTS

In T2DM with HT group, levels of PTH, HbA1c were lower and levels of TSH were significantly higher, when compared with T2DM group. But there was no significant difference in vitamin D between these two groups. In both logistic univariate regression analysis and multiple logistic regression analysis, TSH, HbA1c were independent predictors for T2DM with HT. Based on the ROC curve, the best cut-off value of the TSH was 4 mIU/L (sensitivity 72.7%, specificity 94.6%, AUC = 0.832) for predicting T2DM with HT in T2DM patients.

CONCLUSIONS

TSH has increased risk for T2DM evolving into T2DM complicated with HT, so it is important to monitor the concentrations of TSH in patients with T2DM. Although vitamin D was not the independent predictor in T2DM with HT development, effect of vitamin D deficiency on the progress of diabetes and its complications should be taken into consideration.

Metabolic changes in vitamin D receptor knockout mice

VDR expression has been found in many cell types involved in metabolism, including the beta-cells of the pancreatic islets. Activated vitamin D and its interactions with the vitamin D receptor (VDR) are implicated in glucose homeostasis. We investigated the metabolic phenotype of the VDR-null (VDRKO) mouse at early and middle age. All offspring of heterozygote VDRKO breeding-pairs were fed ‘rescue diet’ from weaning to normalize calcium and phosphate levels in VDRKO and to avoid confounding by different diets. Glucose tolerance testing was performed at 7 and 24 weeks of age. Insulin tolerance testing, glucose-stimulated insulin secretion, body-composition studies and islet isolation were performed at 25–27 weeks. Glucose-stimulated insulin secretion was tested in isolated islets. VDRKO mice had reduced bone density, subcutaneous fat mass and muscle weights compared to WT mice. Despite reduced fat mass, glucose tolerance did not differ significantly. Male but not female VDRKO had improved insulin sensitivity. Global loss of VDR has significant effects on organs involved in energy metabolism and glucose homeostasis. In the setting of decreased fat mass, a clear effect on glucose tolerance was not present.

Insulin Resistance and Vitamin D Deficiency: A Link Beyond the Appearances

Vitamin D is a steroid hormone that plays a key role in the regulation of body homeostasis, including cardiovascular function. Although the chronic deficiency of vitamin D is associated with cardiovascular risk factors, as well as with an adverse prognosis, randomized controlled trials have failed in demonstrating that dietary vitamin D supplementation could ameliorate the prognosis of patients with cardiovascular diseases, and suggested that vitamin D deficiency is the expression of the effects of other determinants of cardiovascular risk. Thus, the supplementation of vitamin D is not sufficient to improve the cardiovascular risk profile and prognosis. Insulin resistance is a complex phenomenon that plays a key role in the pathogenesis of conventional cardiovascular risk factors. Interestingly, defects of vitamin D and insulin resistance have a superimposable epidemiological distribution. According to the common view, Insulin resistance is considered the direct or indirect consequence of vitamin D deficiency. However, it is also reasonable to speculate that the deficit or the impaired action of vitamin D, in some circumstances, could be the result of the same pathogenic mechanisms responsible of insulin resistance development. In this case, vitamin D deficiency could be considered an epiphenomenon of insulin resistance. Insulin resistance is a reversible condition, being possibly ameliorated by physical activity and hypocaloric diets. Notably, both physical exercise and energy-restricted dietary regimens are associated with an increase of vitamin D levels. These findings indicate that improving insulin resistance condition is a necessary step to ameliorate vitamin D supplementation-based strategies in cardiovascular prevention.

The Association Between GC Gene Polymorphisms and Metabolic Syndrome in Chinese Rural Population: A Case-Control Study

BACKGROUND

GC (group-specific component globulin) encoding VDBP (Vitamin D binding protein) polymorphisms have been associated with susceptibility to some diseases such as diabetes, obesity, osteoporosis, and polycystic ovary syndrome, but the evidence for metabolic syndrome (MetS) in the Chinese rural population is inconclusive. Therefore, we investigated the relationship between GC variants (rs7041, rs4588, rs2282679, and rs705117) and MetS risk as well as VDBP levels in the Chinese rural population.

PATIENTS AND METHODS

The participants (range of age: 20-90 years) of this case-control study were recruited from the northern Chinese Han rural population. We matched 445 MetS cases with non-MetS controls in a 1:1 ratio by sex, age (within 5 years). Real-time PCR technology was carried out by TaqMan assays to examine the four variants of rs7041, rs4588, rs2282679, and rs705117 within the GC gene. To identify the association of GC gene polymorphisms with MetS, we calculated ORs using a conditional logistic regression model adjusted for potential confounding factors.

RESULTS

We observed inverse associations of CA and AA genotypes of rs4588 with risk of MetS (OR = 0.678, 95% CI 0.505-0.910, P = 0.010; 0.603, 95% CI 0.373-0.973, P = 0.039, respectively) compared with carriers of CC genotype. A similar relationship was also found between rs2282679 and MetS, showing that carrying AC genotype of rs2282679 can decrease the risk of MetS (OR = 0.683, 95% CI 0.509-0.917, P = 0.011) compared with carriers of AA genotype. The results of correlation analysis between MetS components and GC polymorphisms showed that the ORs of AA genotype of rs4588 with high level of TG (triglycerides) and low level of HDL-C (high-density lipoprotein cholesterol) were 0.473 (95% CI 0.245-0.911, P = 0.025) and 0.268 (95% CI 0.117-0.615, P = 0.002), respectively; the ORs of CC genotype of rs2282679 with high level of TG and low level of HDL-C were 0.428 (95% CI 0.217-0.842, P = 0.014) and 0.263 (95% CI 0.110-0.628, P = 0.003), respectively. However, there was no significant association between the concentration of VDBP and MetS risk.

CONCLUSION

Among the Chinese rural population, GC polymorphism was associated with lower metabolic syndrome susceptibility, which might be through affecting blood lipid levels (TG and HDL-C).

Serum 25(OH)D Levels Modify the Association between Triglyceride and IR: A Cross-Sectional Study

BACKGROUND

Triglycerides and 25(OH)D had been reported as correlates of IR, but the results suggest substantial heterogeneity across races. In addition, little research reported on whether different 25(OH)D levels affect triglycerides and IR. Therefore, a similar study on the US population would be a great addition to the current one. This study investigated the association between triglycerides and IR at different 25(OH)D levels.

METHODS

A total of 19,926 participants were included, each containing specific indicators for the study project. IR was estimated as a HOMA-IR index ≥2.73. Four multivariate logistic regression models were developed to analyze the association between TG and IR and whether different 25(OH)D levels influenced this association. Smoothed fitting curves were plotted.

RESULTS

Triglyceride was significantly associated with IR (OR: 1.3, 95 CI %), while this association received different 25(OH)D levels (P for interaction <0.001). The effect value OR was 1.33 with the high levels, and its effect value OR was 1.28 with the low levels.

CONCLUSION

This study demonstrates that triglyceride levels are significantly associated with insulin in the US adult population and can be used as a predictor of IR. This correlation was compromised at different 25 (OH)D levels, so future studies need to be explored in more ethnically diverse contexts.

Guidance for high-dose vitamin D supplementation for prolonging the honeymoon phase in children and adolescents with new-onset type 1 diabetes

The publication of our recent randomized controlled trial (RCT) showing that vitamin D could protect the β-cells during the honeymoon phase of type 1 diabetes (T1D) has led to calls for guidance for vitamin D supplementation during the critical phase of type 1 diabetes. Prolonging the partial clinical remission (PR) phase of TID improves glycemic control and reduces long-term complications of T1D. This RCT randomized 36 children and adolescents to either receive vitamin D₂ (ergocalciferol, given as 50,000 international units per week for 2 months and then every other week for 10 months) or a placebo. The results showed that vitamin D significantly decreased the temporal rise in both hemoglobin A1c at a mean rate of changes of 0.14% every 3 months versus 0.46% every 3 months for the placebo group (p=0.044); and in the functional marker of PR, the insulin-dose adjusted A1c at a mean rate of change of 0.30% every 3 months versus 0.77% every 3 months for the placebo group, (p=0.015). We recommend a baseline estimation of 25(OH)D concentration at the time of diagnosis of T1D, and to begin vitamin D supplementation if serum 25(OH)D concentration is <30 ng/mL, to maintain serum 25(OH)D concentrations between 30-60 ng/mL. If serum 25(OH)D concentration is >30 ng/mL, monitor vitamin D status with serial 25(OH)D estimations; and initiate vitamin D supplementation if serum 25(OH)D concentrations drop to <30 ng/mL. Continue vitamin D supplementation for at least one year to ensure optimal benefit from vitamin D supplementation during the partial clinical remission phase of type 1 diabetes.

Comparative pharmacokinetic study of bicalutamide administration alone and in combination with vitamin D in rats

Bicalutamide (BCL) has been approved for treatment of advanced prostate cancer (Pca), and vitamin D is inevitably used in combination with BCL in Pca patients for skeletal or anti-tumor strategies. Therefore, it is necessary to study the effect of vitamin D application on the pharmacokinetics of BCL.

We developed and validated a specific, sensitive and rapid UHPLC–MS/MS method to investigate the pharmacokinetic behaviours of BCL in rat plasma with and without the combined use of vitamin D. Plasma samples were extracted by protein precipitation with ether/dichloromethane (2:1 v/v), and the analytes were separated by a Kinetex Biphenyl 100A column (2.1 × 100 mm, 2.6 μm) with a mobile phase composed of 0.5 mM ammonium acetate (PH 6.5) in water (A) and acetonitrile (B) in a ratio of A:B = 35:65 (v/v). Analysis of the ions was run in the multiple reactions monitoring (MRM) mode. The linear range of BCL was 5–2000 ng mL−1. The intra- and inter-day precision were less than 14%, and the accuracy was in the range of 94.4–107.1%. The mean extraction recoveries, matrix effects and stabilities were acceptable for this method. The validated method was successfully applied to evaluate the pharmacokinetic behaviours of BCL in rat plasma. The results demonstrated that the pharmacokinetic property of BCL is significantly affected by combined use of vitamin D, which might help provide useful evidence for the clinical therapy and further pharmacokinetic study.

Effect of vitamin D supplementation on OPG/RANKL signalling activities in endothelial tissue damage in diet-induced diabetic rat model

BACKGROUND

Type 2 Diabetes Mellitus is a chronic metabolic disease that causes endothelial damage and is an important risk factor for atherosclerosis. In the present study vitamin D3 supplementation in rats was used to determine the role of Osteoprotegerin (OPG)/Receptor activator kB ligand (RANKL) signalling in endothelial damage and changes in the expression levels of genes involved in this pathway. We hypothesized that vitamin D3 supplementation affects OPG and RANKL activity in the aorta.

METHODS

Diabetes was induced in rats via injections of 40 mg/kg of streptozotocin followed by a high fructose (10%) diet. Group 2 (healthy) and 4 (diabetic) received 170 IU/kg of vitamin D3 weekly for 5 weeks, while Group 1 (healthy) and 2 (diabetic) received sterile saline. The aortas of each group were collected to analyse mRNA expression using the real-time PCR method and also to evaluate magnesium and calcium levels using inductively coupled plasma mass spectrometry.

RESULTS

Opg and Il-1b expression levels were significantly associated with both diabetes and vitamin D3 supplementation in the aortas of the study groups (p ≤ 0.05). Opg mRNA expression was also found to correlate with both Icam-1 and Nos3 mRNA expression levels (r = 0.699, p = 0.001 and r = 0.622, p = 0.003, respectively). In addition, when mineral levels in the aortic tissues were compared among all groups, it was found that the interaction of diabetes and vitamin D3 supplementation significantly affected Mg levels and Mg/Ca ratios.

CONCLUSIONS

It is concluded that vitamin D3 supplementation has a modulatory effect on OPG/RANKL activity in the vessel wall by ameliorating endothelial damage in diabetes. This effect may contribute to the regulation of cytokine-mediated vascular homeostasis and mineral deposition in the aorta; therefore, further comprehensive studies are proposed to demonstrate this relationship.

Comparison of Profile of Primary Hyperparathyroidism With and Without Type 2 Diabetes Mellitus: Retrospective Analysis From the Indian Primary Hyperparathyroidism Registry

OBJECTIVE

To describe the prevalence and compare the clinicobiochemical profile of patients with primary hyperparathyroidism (PHPT) with and without type 2 diabetes mellitus (T2DM).

METHODS

We conducted a retrospective observational study wherein the details of patients with PHPT with T2DM (PHPT-T2DM) and without T2DM were retrieved from the Indian PHPT Registry (www.indianphptregistry.com) between 2005 and 2019. We compared the clinical, biochemical, and postoperative findings of patients with PHPT-T2DM with age-, sex-, and body mass index-matched patients with PHPT without T2DM (in 1:2 ratio).

RESULTS

Of the 464 patients with PHPT, 54 (11.6%) had T2DM. We observed an increase in the prevalence of PHPT-T2DM cases over time; only 7 (7.1%) of the total patients with PHPT had T2DM between 2005 and 2009 that increased to 31 (12.8%) in the last half decade (2015-2019). Patients with PHPT-T2DM had a significantly lower prevalence of nephrolithiasis (18.5% vs 36.1%, respectively; P = .03) and a higher prevalence of pancreatitis (22.2% vs 5.6%, respectively; P = .007) than those without T2DM. Furthermore, intact parathyroid hormone (203 pg/mL [139.8-437.3 pg/mL] vs 285 pg/mL [166-692 pg/mL], respectively; P = .04) and serum creatinine (0.90 mg/dL [0.67-1.25 mg/dL] vs 1.10 mg/dL [0.73-1.68 mg/dL], respectively; P = .03) levels were significantly lower in patients with PHPT-T2DM than those without T2DM. Also, tumor weight tended to be lower in patients with PHPT-T2DM than in the non-T2DM counterparts (1.05 g [0.5-2.93 g] vs 2.16 g [0.81-7.0 g], respectively; P = .06).

CONCLUSION

The prevalence of T2DM in Asian Indians with PHPT is 11.6%. Patients with PHPT-T2DM are characterized by a higher prevalence of pancreatitis, a lower prevalence of nephrolithiasis, and lower levels of intact parathyroid hormone/creatinine. Part of the clinical picture can possibly be explained by early detection of PHPT in patients with T2DM consequent to more frequent screening.

Vitamin d and leishmaniasis: Neither seasonal nor risk factor in canine host but potential adjuvant treatment through cbd103 expression

Vitamin D (VitD) deficiency has been shown to be a risk factor for a plethora of disorders. We have shown that dogs with clinical leishmaniasis presented lower VitD serum levels than non-infected dogs, and even lower than those with asymptomatic infection. However, if VitD deficiency is a risk factor to develop clinical leishmaniasis remains to be answered. It is also unknown if VitD participates in Leishmania control. First, we retrospectively analysed VitD concentration in serum samples from 36 healthy dogs collected in different periods of the year concluding that there isn't a seasonal variation of this vitamin in dogs. We also included 9 dogs with clinical leishmaniasis and 10 non-infected healthy dogs, in which we measured VitD levels at the beginning of the study, when all dogs were negative for serology and qPCR, and 1 year later. Whereas non-infected dogs showed no change in VitD levels along the study, those developing clinical leishmaniasis showed a significant VitD reduction at the end of the study (35%). When we compared VitD concentration between the two groups at the beginning of the study, no differences were detected (43.6 (38-59) ng/mL, P = 0.962). Furthermore, an in vitro model using a canine macrophage cell line proved that adding active VitD leads to a significant reduction in L. infantum load (31.4%). Analyzing expression of genes related to VitD pathway on primary canine monocytes, we showed that CBD103 expression was significantly enhanced after 1,25(OH)2D addition. Our results show that VitD concentration is neither seasonal nor a risk factor for developing canine leishmaniasis, but it diminishes with the onset of clinical disease suggesting a role in parasitic control. Our in vitro results corroborate this hypothesis and point out that VitD regulates infection through CBD103 expression. These results open the possibility for studies testing VitD as an adjuvant in leishmaniasis therapy.

A Literature Review of the Potential Impact of Medication on Vitamin D Status

In recent years, there has been a significant increase in media coverage of the putative actions of vitamin D as well as the possible health benefits that supplementation might deliver. However, the potential effect that medications may have on the vitamin D status is rarely taken into consideration. This literature review was undertaken to assess the degree to which vitamin D status may be affected by medication. Electronic databases were searched to identify literature relating to this subject, and study characteristics and conclusions were scrutinized for evidence of potential associations. The following groups of drugs were identified in one or more studies to affect vitamin D status in some way: anti-epileptics, laxatives, metformin, loop diuretics, angiotensin-converting enzyme inhibitors, thiazide diuretics, statins, calcium channel blockers, antagonists of vitamin K, platelet aggregation inhibitors, digoxin, potassium-sparing diuretics, benzodiazepines, antidepressants, proton pump inhibitors, histamine H2-receptor antagonists, bile acid sequestrants, corticosteroids, antimicrobials, sulphonamides and urea derivatives, lipase inhibitors, hydroxychloroquine, highly active antiretroviral agents, and certain chemotherapeutic agents. Given that the quality of the data is heterogeneous, newer, more robustly designed studies are required to better define likely interactions between vitamin D and medications. This is especially so for cytochrome P450 3A4 enzyme (CYP3A4)-metabolized medications. Nevertheless, this review suggests that providers of health care ought to be alert to the potential of vitamin D depletions induced by medications, especially in elderly people exposed to multiple-drug therapy, and to provide supplementation if required.

Vitamin D and iodine status was associated with the risk and complication of type 2 diabetes mellitus in China

The purpose of this study was to assess the relationship between 25-hydroxyvitamin D (25(OH)D), urinary iodine concentration (UIC), and type 2 diabetes mellitus (T2DM) risk and complications and to establish a model to predict T2DM in the general population. A total of 567 adults (389 T2DM patients and 178 controls) were enrolled, and the levels of 25(OH)D, iodine, and blood biochemical parameters were measured. Pearson’s correlation analysis showed an inverse correlation between 25(OH)D level, UIC, and T2DM risk. Low 25(OH)D level was a risk factor for developing T2DM (OR, 0.81; 95% CI, 1.90–2.63; P = 0.043) after adjustment for multiple risk factors. 25(OH)D level and UIC were inversely correlated with short-term and long-term glucose levels. 25(OH)D deficiency was also associated with a high incidence of T2DM complicated with thyroid dysfunction. A prediction model based on 25(OH)D, iodine status, and other risk factors was established and recommended to screen high-risk T2DM in the general population and provide early screening and timely treatment for them.

Mechanistic Effects of Vitamin D Supplementation on Metabolic Syndrome Components in Patients with or without Vitamin D Deficiency

The prevalences of metabolic syndrome (MetS) and vitamin D deficiency are increasing dramatically worldwide. MetS is a major challenge because it can increase the risk of most non-communicable diseases. The beneficial effect of vitamin D on MetS components remains controversial, so the present review focused on the clinical effects of vitamin D supplementation on MetS components. Vitamin D can inhibit the protein expression of nuclear factor beta; improve arterial stiffness; decrease renin-angiotensin-aldosterone system activity, parathyroid hormone levels, inflammatory cytokines, 3-hydroxy-3-methylglutaryl-coenzyme A reductase, and lanosterol 14 α-demethylase enzyme activity; increase the activity of lipoprotein lipase; alter gene expression in C2C12 cells; and improve phospholipid metabolism and mitochondrial oxidation. We tried to elucidate and analyze almost all evidence from randomized controlled trial studies of the efficacy of vitamin D supplementation in patients with MetS. The findings of the present study reported beneficial effects of vitamin D supplementation on mentioned factors. Vitamin D supplementation is recommended in people with vitamin D deficiency even if it has no considerable effect on most MetS factors. However, existing data from interventional studies are insufficient to reach a definitive conclusion about the effect of vitamin D supplementation on MetS components in patients without vitamin D deficiency. Thus, new clinical studies are needed to test the hypothesis that vitamin D supplementation could alleviate MetS components in patients with sufficient intake of vitamin D.

Emerging Roles of BRD7 in Pathophysiology

Bromodomain is a conserved structural module found in many chromatin-associated proteins. Bromodomain-containing protein 7 (BRD7) is a member of the bromodomain-containing protein family, and was discovered two decades ago as a protein that is downregulated in nasopharyngeal carcinoma. Since then, BRD7 has been implicated in a variety of cellular processes, including chromatin remodeling, transcriptional regulation, and cell cycle progression. Decreased BRD7 activity underlies the pathophysiological properties of various diseases in different organs. BRD7 plays an important role in the pathogenesis of many cancers and, more recently, its roles in the regulation of metabolism and obesity have also been highlighted. Here, we review the involvement of BRD7 in a variety of pathophysiological conditions, with a focus on glucose homeostasis, obesity, and cancer.

Vitamin D deficiency in patients evaluated for obstructive sleep apnea: is it associated with disease severity?

PURPOSE

The aim of the present study was to assess vitamin D levels in a large cohort of OSA patients and to investigate possible correlations with clinical and polysomnographic parameters.

METHODS

In this cross-sectional study, 685 consecutive patients underwent type 1 polysomnography (PSG) for OSA diagnosis. They were grouped according to apnea-hypopnea index (AHI) as mild, moderate, and severe. Patients with AHI < 5 served as controls. Demographic, PSG data, and serum levels of vitamin D were measured and compared between groups.

RESULTS

OSA was diagnosed in 617 of the patients (90%). Of those, 94 (15%) had mild OSA, 150 (24%) moderate OSA, and 373 (61%) severe OSA. The risk of vitamin D deficiency (< 20 ng/mL) was observed in 38% of the cohort. OSA patients had lower vitamin D levels compared to controls (23 ng/mL vs 26 ng/mL, p = 0.006). The lowest levels of vitamin D [mean 21] (p < 0.001 among all groups) and the higher prevalence for vitamin D deficiency (45%) were observed in severe OSA patients. After multiparametric adjustments for age, gender, obesity, and comorbidities, severe OSA showed significant independent associations with the risk of vitamin D deficiency [OR (95% CI) 2.002 (1.049-3.819), p = 0.035].

CONCLUSIONS

A large proportion of patients referred for OSA evaluation had vitamin D deficiency, which was independently associated with severe OSA. However, further research is needed in order to determine the role of vitamin D in OSA patients.

Clinical factors correlated with vitamin D deficiency in patients with obesity scheduled for bariatric surgery: A single center experience

We aim to assess the prevalence of vitamin D deficiency (VDD) in patients scheduled for bariatric surgery (BS), and to identify factors that might be associated with VDD. We conducted a cross-sectional observational study involving all consecutive patients scheduled for BS from 2017 to 2019. The exclusion criteria were missing data for vitamin D levels, intake of vitamin D supplements in the 3 months prior to serum vitamin D determination, and renal insufficiency. A total of 206 patients (mean age and body mass index [BMI] of 34.9 ± 10.7 years, and 44.3 ± 6.99 kg/m², respectively) met the inclusion criteria and were enrolled for data analysis. VDD (<19.9 ng/mL), severe VDD (<10 ng/mL), and vitamin D insufficiency (20-29.9 ng/mL) were present in 68.8 %, 12.5 %, and 31.2 % of patients, respectively. A significant inverse correlation was found between vitamin D levels and initial BMI, parathyroid hormone, and homeostatic model assessment of insulin resistance (r = -0.280, p < 0.05; r = -0.407, p = 0.038; r = -0.445, p = 0.005), respectively. VDD was significantly more prevalent in patients with higher BMI [-0.413 ± 0.12, CI95 % (-0.659; -0.167), p = 0.006], whereas no significant association between hypertension [-1.005 ± 1.65, CI95 % (-4.338; 2.326), p = 0.001], and diabetes type 2 (T2D) [-0.44 ± 2.20, CI95 % (-4.876; 3.986), p = 0.841] was found. We observed significant association between female sex and levels of vitamin D [6.69 ± 2.31, CI95 % (2.06; 11.33), p = 0.006]. The present study shows that in patients scheduled for BS, VDD deficiency is common and was associated with higher BMI, and female sex.

Vitamin D Receptor Overexpression in β-Cells Ameliorates Diabetes in Mice

Vitamin D deficiency has been associated with increased incidence of diabetes, both in humans and in animal models. In addition, an association between vitamin D receptor (VDR) gene polymorphisms and diabetes has also been described. However, the involvement of VDR in the development of diabetes, specifically in pancreatic β-cells, has not been elucidated yet. Here, we aimed to study the role of VDR in β-cells in the pathophysiology of diabetes. Our results indicate that Vdr expression was modulated by glucose in healthy islets and decreased in islets from both type 1 diabetes and type 2 diabetes mouse models. In addition, transgenic mice overexpressing VDR in β-cells were protected against streptozotocin-induced diabetes and presented a preserved β-cell mass and a reduction in islet inflammation. Altogether, these results suggest that sustained VDR levels in β-cells may preserve β-cell mass and β-cell function and protect against diabetes.

Vitamin D status and its relation to insulin resistance in a Mexican pediatric population

Background Obesity in children and adolescents has increased alarmingly, placing them at a higher risk for impaired glucose tolerance and type 2 diabetes. The prevalence of vitamin D deficiency has increased as well. Vitamin D is critical for glucose homeostasis and insulin secretion. Studies on adults have reported an inverse association between vitamin D levels and insulin resistance (IR), but the results in children are inconsistent. The aim of our study was to determine the association between IR and serum vitamin D levels in obese Mexican children and adolescents. Methods A cross-sectional study was performed on 227 children and adolescents between 6 and 19 years of age. Obesity was diagnosed through body mass index (BMI) for age, according to the World Health Organization (WHO) criteria (2007). 25-Hydroxyvitamin D (25[OH]D) was measured using an immunoassay technique and the homeostatic model assessment of insulin resistance (HOMA-IR) was calculated using the Matthews equation. Student's t-test was carried out. Results The mean serum 25(OH)D level was 35.80 ng/mL, and 55.1% of the subjects had levels classified as sufficient, 33.5% as insufficient, and 11.5% as deficient. The mean level of HOMA-IR was 3.16, and 70% of the subjects were diagnosed with IR. Fasting insulin levels and HOMA-IR were significantly different in adolescents with hypovitaminosis, compared with adolescents in the vitamin D sufficiency group (p = 0.01 and p = 0.03, respectively). Conclusions The insulin levels and HOMA-IR were higher in adolescents with hypovitaminosis. The girls presented higher levels of insulin and HOMA-IR than the boys.

Metformin and Micronutrient Status in Type 2 Diabetes: Does Polypharmacy Involving Acid-Suppressing Medications Affect Vitamin B12 Levels?

Metformin is the first-choice drug in uncomplicated type 2 diabetes (T2DM) and is effective in improving glycaemic control. It is the most widely prescribed oral antidiabetic medicine and has a good safety profile. However, there is an abundance of evidence that metformin use is associated with decreased Vitamin B12 status, though the clinical implications of this in terms of increased risk of diabetic peripheral neuropathy are debated. There is growing evidence that other B vitamins, vitamin D and magnesium may also be impacted by metformin use in addition to alterations to the composition of the microbiome, depending on the dose and duration of therapy. Patients using metformin for prolonged periods may, therefore, need initial screening with intermittent follow-up, particularly since vitamin B₁₂ deficiency has similar symptoms to diabetic neuropathy which itself affects 40-50% of patients with T2DM at some stage. Among patients with T2DM, 40% are reported to experience symptomatic gastroesophageal reflux disease (GORD), of whom 70% use oral antidiabetic medications. The most common medications used to treat GORD are proton pump inhibitors (PPIs) and antagonists of histamine selective H₂ receptors (H₂RAs), both of which independently affect vitamin B₁₂ and magnesium status. Research indicates that co-prescribing metformin with either PPIs or H₂RAs can have further deleterious effects on vitamin B₁₂ status. Vitamin B12 deficiency related to metformin and polypharmacy is likely to contribute to the symptoms of diabetic neuropathy which may frequently be under-recognised. This review explores current knowledge surrounding these issues and suggests treatment strategies such as supplementation.

Impact of the Glycemic Control and Duration of Type 2 Diabetes on Vitamin D Level and Cardiovascular Disease Risk

BACKGROUND AND AIMS

To investigate the impact of glycemic control and T2D duration on vitamin D status and cardiovascular disease (CVD) risk among Saudi patients.

METHODS

This case-control study was conducted in King Faisal Specialist Hospital, Saudi Arabia. A total of 25 nondiabetic controls and 92 patients with confirmed T2D, aged 20-60 years, were included. Patients with T2D were divided into the following groups based on disease duration (newly diagnosed: ≈6 months and long duration: ≥5 years) and glycemic control based on their glycated hemoglobin (HbA_1C) level with a threshold of ≤0.053 mol/mol: newly diagnosed controlled (NC, n = 25), newly diagnosed uncontrolled (NU, n = 25), newly diagnosed uncontrolled (NU, n = 25), newly diagnosed uncontrolled (NU, n = 25), newly diagnosed uncontrolled (NU.

RESULTS

Our study showed that T2D duration was an independent predictor of vitamin D deficiency. The longer disease duration, the lower odds of being vitamin D deficient (odds ratio (OR) = 0.05, 95% CI: 0.01-0.29, p < 0.05). No significant association was observed between vitamin D and HbA_1C levels. In the NU group, CVD risk scores were directly correlated with serum 25(OH)D (r = 0.53, p < 0.05). No significant association was observed between vitamin D and HbA_1C levels. In the NU group, CVD risk scores were directly correlated with serum 25(OH)D (r = 0.53, p < 0.05). No significant association was observed between vitamin D and HbA_1C levels. In the NU group, CVD risk scores were directly correlated with serum 25(OH)D (.

CONCLUSION

Duration of diabetes rather than glycemic control is associated with vitamin D deficiency. Glycemic uncontrol may augment vitamin D deficiency-associated CVD risk in both newly diagnosed and old patients with type 2 diabetes.

The Protective Role of Calbindin-D9k on Endoplasmic Reticulum Stress-Induced Beta Cell Death

Intracellular calcium ion content is tightly regulated for the maintenance of cellular functions and cell survival. Calbindin-D_9k (CaBP-9k) is responsible for regulating the distribution of cytosolic free-calcium ions. In this study, we aimed to investigate the effect of CaBP-9k on cell survival in pancreatic beta cells. Six-month-old wildtype CaBP-9k, CaBP-28k, and CaBP-9k/28k knockout (KO) mice were used to compare the pathological phenotypes of calcium-binding protein-deleted mice. Subsequently, the endoplasmic reticulum (ER) stress reducer tauroursodeoxycholic acid (TUDCA) was administered to wildtype and CaBP-9k KO mice. In vitro assessment of the role of CaBP-9k was performed following CaBP-9k overexpression and treatment with the ER stress inducer thapsigargin. Six-month-old CaBP-9k KO mice showed reduced islet volume and up-regulation of cell death markers resulting from ER stress, which led to pancreatic beta cell death. TUDCA treatment recovered islet volume, serum insulin level, and abdominal fat storage by CaBP-9k ablation. CaBP-9k overexpression elevated insulin secretion and recovered thapsigargin-induced ER stress in the INS-1E cell line. The results of this study show that CaBP-9k can protect pancreatic beta cell survival from ER stress and contribute to glucose homeostasis, which can reduce the risk of type 1 diabetes and provide the molecular basis for calcium supplementation to diabetic patients.

Regulation of somatostatin expression by vitamin D3 and valproic acid in human adipose-derived mesenchymal stem cells

BACKGROUND

Adipose-derived mesenchymal stem cells (ADMSC) are non-haematopoietic, fibroblast-like multipotent progenitor cells. They have the potential for trilineage (adipocyte, chondrocyte and osteocyte) differentiation as well as differentiation into endocrine pancreatic progenitors. In diabetic or cancer therapy, somatostatin (SST) expression plays a vital role. Small molecules such as valproic acid (VPA) and micronutrients like vitamin D3 have differentiation potential in ADMSC. Therefore, the aim of this study was to investigate the role of vitamin D3 machinery and its metabolic enzymes in ADMSC. Furthermore, the reprogramming effect of vitamin D3 and VPA was evaluated on somatostatin expression in pancreatic lineage differentiation.

METHODS

ADMSC were characterised based on their cell surface marker profile using flow cytometry. Specific adipogenic and osteogenic differentiation protocols were used in this study. Gene expression of several pluripotent, endodermal, pancreatic progenitor and pancreatic endocrine lineage markers were investigated in native ADMSC and after stimulation with different concentration of vitamin D3 for five consecutive days (0, 50, 100, 150 nM) and VPA (0.5, 1, 1.5, 2 mM) by real-time PCR. Furthermore, somatostatin expression was confirmed with ELISA and immunocytochemistry.

RESULTS

In ADMSC, the expression of somatostatin mRNA, the vitamin D receptor (VDR) and its metabolising enzymes 1 α-Hydroxylase, 24-Hydroxylase and 25-Hydroxylase were detected. Upon stimulation with vitamin D3, nuclear translocation of vitamin D receptor (VDR) was observed. Interestingly, the presence of vitamin D3 reduced the transcription of the somatostatin gene. By contrast, VPA treatment of cultivated ADMSC showed enhancing effect on somatostatin gene expression. No other pluripotent, endodermal, pancreatic progenitor or pancreatic endocrine lineage mRNA expression was modulated under the influence of vitamin D3 and VPA.

CONCLUSION

Human ADMSC carry the VDR. The vitamin D metabolising enzyme 25-Hydroxylase responded to the addition of vitamin D3. Moreover, our results demonstrate that somatostatin expression in ADMSC is constitutive, partially secreted and regulated by vitamin D3 and VPA.

Bystander activation and autoimmunity

The interaction over time of genetic, epigenetic and environmental factors (i.e., autoimmune ecology) increases or decreases the liability an individual would have to develop an autoimmune disease (AD) depending on the misbalance between risk and protective effects. Pathogens have been the most common antecedent events studied, but multiple other environmental factors including xenobiotic chemicals, drugs, vaccines, and nutritional factors have been implicated into the development of ADs. Three main mechanisms have been offered to explain the development of autoimmunity: molecular mimicry, epitope spreading, and bystander activation. The latter is characterized by auto-reactive B and T cells that undergo activation in an antigen-independent manner, influencing the development and course of autoimmunity. Activation occurs due to a combination of an inflammatory milieu, co-signaling ligands, and interactions with neighboring cells. In this review, we will discuss the studies performed seeking to define the role of bystander activation in systemic and organ-specific ADs. In all cases, we are cognizant of individual differences between hosts and the variable latency time for clinical expression of disease, all of which have made our understanding of the etiology of loss of immune tolerance difficult and enigmatic.

Vitamin D status in diabetic patients (type 2) and its relation to glycemic control & diabetic nephropathy

BACKGROUND

Vitamin D deficiency appears to be lower in diabetic patients. Vitamin D may affect glycemic control & diabetic nephropathy.

AIM

To assess vitamin D level in type 2 diabetic patients and its relation to their glycemic control and development of nephropathy compared to healthy controls.

DESIGN

and Setting: Case control study including 82 participants (41 cases and 41 controls) from Family Medicine Clinic, Cairo University Hospitals.

METHOD

Participants fulfilling the inclusion criteria were allocated into two groups, diabetes and control groups. History was taken, examination was done, and blood sample was withdrawn for analysis of Vitamin D levels and HBA1C. From the diabetic group only, serum creatinine was assessed and urine sample was collected for microalbuminuria. The results were analyzed using SPSS program version 21.

RESULTS

Vitamin D level was lower in the diabetic group compared to control (65.5% and 56.1%). Vitamin D level was inversely proportionate to HbA1c levels in the diabetic patients (p value 0.000 & r -0.482), as well as to the A/C ratio (p value 0.01 & r -0.396).

CONCLUSION

Vitamin D level appeared to be lower in diabetic patients and is associated with poor glycemic control & microalbuminuria.

Local In Vivo Measures of Muscle Lipid and Oxygen Consumption Change in Response to Combined Vitamin D Repletion and Aerobic Training in Older Adults

Intramyocellular (IMCL), extramyocellular lipid (EMCL), and vitamin D deficiency are associated with muscle metabolic dysfunction. This study compared the change in [IMCL]:[EMCL] following the combined treatment of vitamin D and aerobic training (DAT) compared with vitamin D (D), aerobic training (AT), and control (CTL). Male and female subjects aged 60–80 years with a BMI ranging from 18.5–34.9 and vitamin D status of ≤32 ng/mL (25(OH)D) were recruited to randomized, prospective clinical trial double-blinded for supplement with a 2 × 2 factorial design. Cholecalciferol (Vitamin D₃) (10,000 IU × 5 days/week) or placebo was provided for 13 weeks and treadmill aerobic training during week 13. Gastrocnemius IMCL and EMCL were measured with magnetic resonance spectroscopy (MRS) and MRI. Hybrid near-infrared diffuse correlation spectroscopy measured hemodynamics. Group differences in IMCL were observed when controlling for baseline IMCL (p = 0.049). DAT was the only group to reduce IMCL from baseline, while a mean increase was observed in all other groups combined (p = 0.008). IMCL reduction and the corresponding increase in rVO₂ at study end (p = 0.011) were unique to DAT. Vitamin D, when combined with exercise, may potentiate the metabolic benefits of exercise by reducing IMCL and increasing tissue-level VO₂ in healthy, older adults.

Effects of vitamin D supplementation on metabolic and endocrine parameters in healthy premenopausal women: A randomized controlled trial

BACKGROUND & AIMS

Vitamin D supplementation may affect glycemic as well as hormonal regulation. Thus, the aim of the current study was to investigate whether vitamin D supplementation has any significant effects on metabolic and endocrine parameters in healthy premenopausal women. Primary outcome measure was the plasma glucose area under the curve (AUCgluc).

METHODS

The current study was a single-center, double-blind, randomized placebo-controlled trial that was conducted at the Medical University of Graz, Austria, between March 2013 and October 2017. One-hundred and fifty healthy premenopausal women with 25-hydroxyvitamin D [25(OH)D] concentrations <75 nmol/L once weekly received either 20,000 IU of cholecalciferol or placebo (2:1 ratio) over a total of 24 weeks.

RESULTS

In total, 127 women [age 36.2 ± 8.7 years; BMI 25.3 ± 5.6 kg/m²; baseline 25(OH)D 55.8 ± 19.7 nmol/L] completed the study. Vitamin D supplementation had no significant effect on AUCgluc (mean treatment effect 11.70; p = 0.069), while it had a significant treatment effect on homeostatic model assessment-insulin resistance (HOMA-IR; mean treatment effect 0.31; p = 0.019) and quantitative insulin-sensitivity check index (QUICKI; mean treatment effect -0.019; p = 0.013). There was no significant effect on the remaining secondary outcome parameters.

CONCLUSIONS

In this randomized-controlled trial in healthy premenopausal women, there was a significant treatment effect of vitamin D supplementation on HOMA-IR and QUICKI, while there was no significant treatment effect on AUCgluc.

Vitamin D status and the risk of type 2 diabetes: The Melbourne Collaborative Cohort Study

AIMS

Inverse associations between vitamin D status and risk of type 2 diabetes observed in epidemiological studies could be biased by confounding and reverse causality. We investigated the prospective association between vitamin D status and type 2 diabetes and the possible role of reverse causality.

METHODS

We conducted a case-cohort study within the Melbourne Collaborative Cohort Study (MCCS), including a random sample of 628 participants who developed diabetes and a sex-stratified random sample of the cohort (n = 1884). Concentration of 25-hydroxyvitamin D (25(OH)D) was measured using liquid chromatography-tandem mass spectrometry in samples collected at recruitment. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the risk of type 2 diabetes for quartiles of 25(OH)D relative to the lowest quartile and per 25 nmol/L increase in 25(OH)D, adjusting for confounding variables.

RESULTS

The ORs for the highest versus lowest 25(OH)D quartile and per 25 nmol/L increase in 25(OH)D were 0.60 (95% CI: 0.44, 0.81) and 0.76 (95% CI: 0.63, 0.92; p = 0.004), respectively. In participants who reported being in good/very good/excellent health approximately four years after recruitment, ORs for the highest versus lowest 25(OH)D quartile and per 25 nmol/L increase in 25(OH)D were 0.46 (95% CI: 0.29, 0.72) and 0.71 (95% CI: 0.56, 0.89; p = 0.003), respectively.

CONCLUSIONS

In this sample of middle-aged Australians, vitamin D status was inversely associated with the risk of type 2 diabetes, and this association did not appear to be explained by reverse causality.

Effects of vitamin D supplementation on advanced glycation end products signaling pathway in T2DM patients: a randomized, placebo-controlled, double blind clinical trial

BACKGROUND

Several researches have recommended vitamin D possible health benefits on diabetic complications development, but a few number of studies have been accomplished on the molecular and cellular mechanisms. Certain cellular pathways modification and also some transcription factors activation may protect cells from hyperglycemia condition induced damages. This study purpose was to determine the vitamin D supplementation effect on some key factors [advanced glycation end products (AGEs) signaling pathway] that were involved in the diabetic complications occurrence and progression for type-2 diabetes participants.

METHODOLOGY

48 type-2 diabetic patients (T2DM) randomly divided into two groups (n = 24 per group), receiving: 100-µg vitamin D or placebo for 3 months. At this study beginning and the end, the receptor expression for advanced glycation end products (RAGE) and glyoxalase I (GLO1) enzyme from peripheral blood mononuclear cells (PBMCs) and AGEs and tumor necrosis factor-α (TNF-α) serum levels were measured by the use of real-time PCR and ELISA methods, respectively.

RESULTS

This study results demonstrated that vitamin D supplementation could down-regulate RAGE mRNA [fold change = 0.72 in vitamin D vs. 0.95 in placebo) P = 0.001)]. In addition, no significant changes were observed for GLO1 enzyme expression (P = 0.06). This study results also indicated that vitamin D serum level significantly increased in vitamin D group (P < 0.001). Moreover, AGES and TNF-α serum levels significantly reduced in vitamin D group, but they were remained unchanged in the placebo group.

CONCLUSION

In conclusion, vascular complications are more frequent in diabetic patients, and vitamin D treatment may prevent or delay the complications onset in these patients by AGEs serum level and RAGE gene expression reducing.Trial registration NCT03008057. Registered December 2016.