Vitamin D in the Spectrum of Prediabetes and Cardiovascular Autonomic Dysfunction

Cardiovascular Risk Among Saudi Adults with Prediabetes: A Sub-Cohort Analysis from the Heart Health Promotion (HHP) Study

Background

This study aimed to estimate the prevalence of prediabetes among Saudi adults and to evaluate their risk of developing cardiovascular diseases.

Methods

This is a cohort of 2470 Saudi adults attending employee clinics in the university hospital. WHO-STEPs approach was used to collect sociodemographic (age, gender, and education), clinical (body mass index and blood pressure) and laboratory data (HbA1c, lipid profile and vitamin D concentration). Prediabetes was defined according to HbA1c level of 5.7–6.4%. Cardiovascular risk (CVR) scores were evaluated using the Framingham Risk Score. SPSS was used for data analysis to investigate the relation between different CVR and prediabetes.

Results

Prediabetes affected 25.1% of the study population. Males had higher rates of prediabetes than females (27.5% versus 23.5%). The prevalence of prediabetes increased from 11.6% among young individuals (18–29 years) to 56.0% among participants 60 years and older. Prediabetes patients exhibited considerably higher levels of all cardiovascular risk factors and nearly half of them (49.3%) had at least two risk factors. The prevalence of intermediate CVR among prediabetics was 13.2% compared to just 2.9% among the normal group, and high CVR was defined in 3.7% among prediabetics compared to only 1.7% in the normal group. Having prediabetes increased the odds to develop higher CVR of 2.64 times compared to those without prediabetes (OR = 2.64, 95% CI = 1.51–4.64) and the level of vitamin D did not affect the odds of CVR.

Conclusion

Prediabetes is quite prevalent among Saudi adults, and they are at a higher risk of cardiovascular diseases. Patients with prediabetes have higher cardiac risk scores when compared to normal participants across the whole spectrum of (25(OH)D) concentrations. Additionally, no significant correlation was observed between HbA1c and (25(OH)D) levels in prediabetics or normoglycemic subjects.

The Gestational Effects of Maternal Bone Marker Molecules on Fetal Growth, Metabolism and Long-Term Metabolic Health: A Systematic Review

Fetal exposure in adverse environmental factors during intrauterine life can lead to various biological adjustments, affecting not only in utero development of the conceptus, but also its later metabolic and endocrine wellbeing. During human gestation, maternal bone turnover increases, as reflected by molecules involved in bone metabolism, such as vitamin D, osteocalcin, sclerostin, sRANKL, and osteoprotegerin; however, recent studies support their emerging role in endocrine functions and glucose homeostasis regulation. Herein, we sought to systematically review current knowledge on the effects of aforementioned maternal bone biomarkers during pregnancy on fetal intrauterine growth and metabolism, neonatal anthropometric measures at birth, as well as on future endocrine and metabolic wellbeing of the offspring. A growing body of literature converges on the view that maternal bone turnover is likely implicated in fetal growth, and at least to some extent, in neonatal and childhood body composition and metabolic wellbeing. Maternal sclerostin and sRANKL are positively linked with fetal abdominal circumference and subcutaneous fat deposition, contributing to greater birthweights. Vitamin D deficiency correlates with lower birthweights, while research is still needed on intrauterine fetal metabolism, as well as on vitamin D dosing supplementation during pregnancy, to diminish the risks of low birthweight or SGA neonates in high-risk populations.

Potential role of 25(OH)D insufficiency in the dysfunction of glycolipid metabolism and cognitive impairment in patients with T2DM

PURPOSE

To investigate the changes of plasma 25(OH)D levels in type 2 diabetes mellitus (T2DM) patients and explore its role in the dysfunction of glucose and lipid metabolism and cognition.

METHODS

One hundred and thirty-two T2DM patients were enrolled and the demographic and clinical data were collected. The plasma concentration of 25(OH)D was detected and the patients were divided into two groups including a Vitamin D insufficient (VDI) group and a normal VD group according to the clinical diagnostic criterial of VDI with the plasma 25(OH)D level less than 29 ng/mL. The glycolipid metabolic and routine blood biochemical indices were detected, the plasma concentrations of C-reactive protein (CRP), interleukin-6 (IL-6), soluble myeloid soluble trigger receptor 1 (sTREM1) were measured. The cognitive function was assessed using the Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A). The depressive symptomatology was assessed using the Center for Epidemiological Survey Depression Scale (CES-D). Sleep quality was assessed using the Pittsburgh sleep quality index (PSQI).

RESULTS

There were 70 T2DM patients with VDI (70/132, 53.03%) in this study. The plasma concentrations of glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), postprandial blood glucose (PBG), IL-6, and sTREM1 were remarkably increased in T2DM patients with VDI as compared with that with the normal VD, accompanied with an elevated BRIEF-A scores. There was no significant difference between groups with regard to the indices of blood lipid, liver function, and scores in CES-D and PSQI. Moreover, results of Pearson correlation test showed that the plasma 25(OH)D levels were negatively correlated with HbA1c, FPG, PBG, CRP, IL-6, sTREM1, CES-D sum scores, and PSQI sum scores, but positively correlated with the plasma levels of Serum creatinine (Scr). Furthermore, result of Receiver Operating Characteristic (ROC) curve analysis showed a predictive role of VDI levels in discriminating T2DM patients with higher cognitive impairments, with the sensitivity and specificity being 62.12% and 62.12%, respectively.

CONCLUSION

VDI is harmful for T2DM patients with a significant relation with the hyperglycosemia and cognitive dysfunction.

Effect of Vitamin D status on QTc interval in type 2 diabetes mellitus

OBJECTIVES

Diabetes mellitus (DM) is associated with autonomic neuropathy and metabolic abnormalities. These predispose the patients to prolongation of QTc and risk of arrhythmias and sudden cardiac death. Vitamin D may also cause QTc prolongation. We hypothesized that concomitant Vitamin D deficiency and Type 2 DM may act in synergy to prolong QTc interval.

METHODS

Newly diagnosed Type 2 DM patients were recruited from Department of Endocrinology. Lead II ECG was acquired for 5 min during supine rest using a digital data acquisition system. QTc interval extraction was performed using software. 25-hydroxy Vitamin D estimation was done using Chemiluminescence method. Patients were divided into two groups- Vitamin D deficient and insufficient (VDD/I) and optimal (VDO) as per standard criteria. QTc intervals were compared between the two groups.

RESULTS

Sixty-five patients participated in the study. Age was comparable between the groups (p=0.67, Unpaired t-test). There was no significant difference amongst QTc intervals between the groups (p=0.19, Mann Whitney test). Also, there was no significant correlation between Vitamin D levels and QTc intervals assessed using Spearman's correlation coefficient.

CONCLUSIONS

While it seems plausible, coexisting Vitamin D deficiency and Type 2 DM probably do not act in synergy to prolong QTc interval. These findings merit future research on larger cohorts to investigate the relationship between Vitamin D status and newly diagnosed Type 2 DM on QTc intervals.

Cluster and Factor Analysis of Elements in Serum and Urine of Diabetic Patients with Peripheral Neuropathy and Healthy People

Diabetic peripheral neuropathy (DPN) is a common complication of diabetes mellitus, presented as a major teratogenic cause worldwide. This study discussed alternation and correlation of magnesium (Mg), calcium (Ca), copper (Cu), zinc (Zn), iron (Fe), chromium (Cr), and selenium (Se) among DPN patients and healthy people using multivariate statistical analysis. Fifty patients with DPN were recruited from endocrinology department, First Hospital of Jilin University between January 2010 and October 2011 and also 50 healthy subjects were enrolled at the same time. Inductively coupled plasma mass spectrometry (ICP-MS) was used to assay elements in serum and urine. Cluster analysis was used to clarify alternation of elements' homogeneity. Factor analysis was performed to evaluate the most informative kinds of elements. Mg, Ca, Zn, and Cr in DPN patients were significantly lower in serum whereas significantly higher in urine. Elements were clustered into 4 or 5 clusters based on internal association using between-groups linkage algorithm. Serum Cr, Se, and Fe were grouped, and Mg related to Ca more closely in both serum and urine in DPN. Factor analysis revealed discrepancies of elements' contribution. Cr, Se, and Fe appeared to be the most crucial factors contributing to DPN. Mg, Ca, Zn, and Cu were more influential, whereas Cr became less potent to disease. Contributed value of elements could be determined and specified using loadings in scree plot. Future studies and delicate statistical models should be applied.

Focus on 1,25-Dihydroxyvitamin D3 in the Peripheral Nervous System

In this review, we draw attention to the roles of calcitriol (1,25-dihydroxyvitamin D3) in the trophicity of the peripheral nervous system. Calcitriol has long been known to be crucial in phosphocalcium homeostasis. However, recent discoveries concerning its involvement in the immune system, anti-cancer defenses, and central nervous system development suggest a more pleiotropic role than previously thought. Several studies have highlighted the impact of calcitriol deficiency as a promoting factor of various central neurological diseases, such as multiple sclerosis, amyotrophic lateral sclerosis, Parkinson's disease, and Alzheimer's disease. Based on these findings and recent publications, a greater role for calcitriol may be envisioned in the peripheral nervous system. Indeed, calcitriol is involved in myelination, axonal homogeneity of peripheral nerves, and neuronal-cell differentiation. This may have useful clinical consequences, as calcitriol supplementation may be a simple means to avoid the onset and/or development of peripheral nervous-system disorders.

The serum vitamin D metabolome: What we know and what is still to discover

Vitamin D, referring to the two forms, D2 from the diet and D3 primarily derived from phototransformation in the skin, is a prohormone important in human health. The most hormonally active form, 1α,25-dihydroxyvitamin D (1α,25(OH)₂D), formed from vitamin D via 25-hydroxyvitamin D (25(OH)D), is not only important for regulating calcium metabolism, but has many pleiotropic effects including regulation of the immune system and has anti-cancer properties. The major circulating form of vitamin D is 25(OH)D and both D2 and D3 forms are routinely measured by LC/MS/MS to assess vitamin D status, due to their relatively long half-lives and much higher concentrations compared to 1α,25(OH)₂D. Inactivation of both 25(OH)D and 1α,25(OH)₂D is catalyzed by CYP24A1 and 25-hydroxyvitamin D3 3-epimerase. Initial products from these enzymes acting on 25(OH)D3 are 24R,25(OH)₂D3 and 3-epi-25(OH)D3, respectively, and both of these can also be measured routinely in some clinical laboratories to further document vitamin D status. With advances in LC/MS/MS and its increased availability, and with the help of studies with recombinant vitamin D-metabolizing enzymes, many other vitamin D metabolites have now been detected and in some cases quantitated, in human serum. CYP11A1 which catalyzes the first step in steroidogenesis, has been found to also act on vitamins D3 and D2 hydroxylating both at C20, but with some secondary metabolites produced by subsequent hydroxylations at other positions on the side chain. The major vitamin D3 metabolite, 20S-hydroxyvitamin D3 (20S(OH)D3), shows biological activity, often similar to 1α,25(OH)₂D3 but without calcemic effects. Using standards produced enzymatically by purified CYP11A1 and characterized by NMR, many of these new metabolites have been detected in human serum, with semi-quantitative measurement of 20S(OH)D3 indicating it is present at comparable concentrations to 24R,25(OH)₂D3 and 3-epi-25(OH)D3. Recently, vitamin D-related hydroxylumisterols derived from lumisterol3, a previtamin D3 photoproduct, have also been measured in human serum and displayed biological activity in initial in vitro studies. With the current extensive knowledge on the reactions and pathways of metabolism of vitamin D, especially those catalyzed by CYP24A1, CYP27A1, CYP27B1, CYP3A4 and CYP11A1, it is likely that many other of the resulting hydroxyvitamin D metabolites will be measured in human serum in the future, some contributing to a more detailed understanding of vitamin D status in health and disease.

The role of vitamin D in perinatology. An up-to-date review

The role of vitamin D in perinatology is a subject of major interest in current medicine. There is growing evidence about the role of maternal vitamin D levels in pregnancy outcomes. The aim of this review is to summarize the current literature about the role of vitamin D in perinatology. Evidence from this review suggests associations between low levels of maternal vitamin D and higher risk of certain obstetrical complications. Vitamin D has been found to be related to preeclampsia, gestational diabetes mellitus, low birth weight, and preterm birth. The current literature supports vitamin D supplementation in pregnant women, but more high-quality data are necessary. The problem that remains is how to achieve an optimal 25-hydroxyvitamin D level. To determine the real benefits of vitamin D supplementation in pregnancy, we need high-quality trials in larger groups.

Association of l-Arginine Supplementation with Markers of Endothelial Function in Patients with Cardiovascular or Metabolic Disorders: A Systematic Review and Meta-Analysis

l-Arginine supplementation is a potential therapy for treating cardiovascular and metabolic diseases. However, the use of distinct l-arginine sources, intervened populations, and treatment regimens may have yielded confusion about their efficacy. This research constitutes a systematic review and meta-analysis summarizing the effects of l-arginine supplementation compared to placebo in individuals with cardiovascular disease (CVD), obesity, or diabetes. Eligibility criteria included randomized clinical trials and interventions based on oral supplementation of l-arginine with a minimum duration of three days; comparison groups consisted of individuals with the same disease condition receiving an oral placebo substance. The primary outcome was flow-mediated dilation, and secondary outcomes were nitrite/nitrate (NOx) rate and asymmetric dimethylarginine (ADMA). Statistical heterogeneity among studies included in the meta-analyses was assessed using the inconsistency index (I2). Fifty-four full-text articles from 3761 retrieved references were assessed for eligibility. After exclusions, 13 studies were included for data extraction. There was no difference in blood flow after post-ischemic hyperemia between the supplementation of l-arginine and placebo groups before and after the intervention period (standardized mean difference (SMD) = 0.30; 95% confidence intervals (CIs) = −0.85 to 1.46; I2 = 96%). Sensitivity analysis showed decreased heterogeneity when the studies that most favor arginine and placebo were removed, and positive results in favor of arginine supplementation were found (SMD = 0.59; 95% CIs = 0.10 to 1.08; I2 = 75%). No difference was found in meta-analytical estimates of NOx and ADMA responses between arginine or placebo treatments. Overall, the results indicated that oral l-arginine supplementation was not associated with improvements on selected variables in these patients (PROSPERO Registration: CRD42017077289).

Differential and Overlapping Effects of 20,23(OH)₂D3 and 1,25(OH)₂D3 on Gene Expression in Human Epidermal Keratinocytes: Identification of AhR as an Alternative Receptor for 20,23(OH)₂D3

A novel pathway of vitamin D activation by CYP11A has previously been elucidated. To define the mechanism of action of its major dihydroxy-products, we tested the divergence and overlap between the gene expression profiles of human epidermal keratinocytes treated with either CYP11A1-derived 20,23(OH)₂D3 or classical 1,25(OH)₂D3. Both secosteroids have significant chemical similarity with the only differences being the positions of the hydroxyl groups. mRNA was isolated and examined by microarray analysis using Illumina’s HumanWG-6 chip/arrays and subsequent bioinformatics analyses. Marked differences in the up- and downregulated genes were observed between 1,25(OH)₂D3- and 20,23(OH)₂D3-treated cells. Hierarchical clustering identified both distinct, opposite and common (overlapping) gene expression patterns. CYP24A1 was a common gene strongly activated by both compounds, a finding confirmed by qPCR. Ingenuity pathway analysis identified VDR/RXR signaling as the top canonical pathway induced by 1,25(OH)₂D3. In contrast, the top canonical pathway induced by 20,23(OH)₂D3 was AhR, with VDR/RXR being the second nuclear receptor signaling pathway identified. QPCR analyses validated the former finding by revealing that 20,23(OH)₂D3 stimulated CYP1A1 and CYP1B1 gene expression, effects located downstream of AhR. Similar stimulation was observed with 20(OH)D3, the precursor to 20,23(OH)₂D3, as well as with its downstream metabolite, 17,20,23(OH)₃D3. Using a Human AhR Reporter Assay System we showed marked activation of AhR activity by 20,23(OH)₂D3, with weaker stimulation by 20(OH)D3. Finally, molecular modeling using an AhR LBD model predicted vitamin D3 hydroxyderivatives to be good ligands for this receptor. Thus, our microarray, qPCR, functional studies and molecular modeling indicate that AhR is the major receptor target for 20,23(OH)₂D3, opening an exciting area of investigation on the interaction of different vitamin D3-hydroxyderivatives with AhR and the subsequent downstream activation of signal transduction pathways in a cell-type-dependent manner.

Associations between serum vitamin D and the risk of female reproductive tumors: A meta-analysis with trial sequential analysis

BACKGROUND

Female reproductive tumors are common with high morbidity and mortality worldwide; however, the association between gynecological tumors and serum vitamin D is controversial. The aim of this meta-analysis was to evaluate the relationship between insufficiency of serum vitamin D and the occurrence of benign and malignant gynecological tumors.

METHODS

Studies from inception to June 2017 were searched in the electronic databases: National Library of Medicine (PubMed), Web of Science (Clerivate), and Cochrane Database of Systematic Reviews (Cochrane Library, CDSR) by 2 investigators independently. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using a random-effects model. STATA 12.0 Software and Trial Sequential Analysis (TSA) software were applied for data analyses.

RESULTS

Overall, 8 studies (including 2391 patients and 5798 patients with and without female reproductive tumors, respectively) were eligible for the present meta-analysis. In the subsequent meta-analysis, the occurrence of vitamin D deficiency in the case and control groups were 52.36% and 48.70%, respectively; women with female reproductive benign and malignant tumors were 55.57% and 50.59%, respectively. Although, no conclusive association was found between vitamin D deficiency and female reproductive tumors (OR, 1.05; 95% CI, 0.85-1.31); vitamin D deficiency may be a risk factor of malignant female reproductive neoplasm, as shown by the pooled OR (95% CI):1.17 (1.02-1.33). Furthermore, based on the OR values, association of vitamin D insufficiency with disease type, study location, number of patients, and methods for detecting CLA was observed. Similar results in the sensitivity analysis were observed. TSA showed that the cumulative Z-curve crossed the traditional boundary line, rather than crossing the trial sequential monitoring boundary. However, the cumulative information failed to reach the required information size.

CONCLUSIONS

Currently, vitamin D deficiency appears to be a common issue in females, and there may be an urgent need to improve the level of vitamin D. Furthermore, vitamin D deficiency may be a non-negligible risk factor of malignant female reproductive neoplasm. Undoubtedly, more trials are required in the future according to TSA.