The combination of vitamin D3 and dehydroascorbic acid administration attenuates brain damage in focal ischemia

Vitamin D: The crucial neuroprotective factor for nerve cells

Vitamin D is well known for its role in regulating the absorption and utilization of calcium and phosphorus as well as bone formation, and a growing number of studies have shown that vitamin D also has important roles in the nervous system, such as maintaining neurological homeostasis and protecting normal brain function, and that neurons and glial cells may be the targets of these effects. Most reviews of vitamin D's effects on the nervous system have focused on its overall effects, without distinguishing the contributors to these effects. In this review, we mainly focus on the cells of the central nervous system, summarizing the effects of vitamin D on them and the related pathways. With this review, we hope to elucidate the role of vitamin D in the nervous system at the cellular level and provide new insights into the prevention and treatment of neurodegenerative diseases in the direction of neuroprotection, myelin regeneration, and so on.

Full spectrum of vitamin D immunomodulation in multiple sclerosis: mechanisms and therapeutic implications

Vitamin D deficiency has been associated with the risk of multiple sclerosis, disease activity and progression. Results from in vitro experiments, animal models and analysis of human samples from randomized controlled trials provide comprehensive data illustrating the pleiotropic actions of Vitamin D on the immune system. They globally result in immunomodulation by decreasing differentiation of effector T and B cells while promoting regulatory subsets. Vitamin D also modulates innate immune cells such as macrophages, monocytes and dendritic cells, and acts at the level of the blood–brain barrier reducing immune cell trafficking. Vitamin D exerts additional activity within the central nervous system reducing microglial and astrocytic activation. The immunomodulatory role of Vitamin D detected in animal models of multiple sclerosis has suggested its potential therapeutic use for treating multiple sclerosis. In this review, we focus on recent published data describing the biological effects of Vitamin D in animal models of multiple sclerosis on immune cells, blood–brain barrier function, activation of glial cells and its potential neuroprotective effects. Based on the current knowledge, we also discuss optimization of therapeutic interventions with Vitamin D in patients with multiple sclerosis, as well as new technologies allowing in-depth analysis of immune cell regulations by vitamin D.

Neuroprotective Properties of Vitamin C: A Scoping Review of Pre-Clinical and Clinical Studies

There is a need for novel neuroprotective therapies. We aimed to review the evidence for exogenous vitamin C as a neuroprotective agent. MEDLINE, Embase, and Cochrane library databases were searched from inception to May 2020. Pre-clinical and clinical reports evaluating vitamin C for acute neurological injury were included. Twenty-two pre-clinical and 11 clinical studies were eligible for inclusion. Pre-clinical studies included models of traumatic and hypoxic brain injury, subarachnoid and intracerebral hemorrhage, and ischemic stroke. The median [IQR] maximum daily dose of vitamin C in animal studies was 120 [50-500] mg/kg. Twenty-one animal studies reported improvements in biomarkers, functional outcome, or both. Clinical studies included single reports in neonatal hypoxic encephalopathy, traumatic brain injury, and subarachnoid hemorrhage and eight studies in ischemic stroke. The median maximum daily dose of vitamin C was 750 [500-1000] mg, or ∼10 mg/kg for an average-size adult male. Apart from one case series of intracisternal vitamin C administration in subarachnoid hemorrhage, clinical studies reported no patient-centered benefit. Although pre-clinical trials suggest that exogenous vitamin C improves biomarkers of neuroprotection, functional outcome, and mortality, these results have not translated to humans. However, clinical trials used approximately one tenth of the vitamin C dose of animal studies.

Vitamin D3 mitigates lipopolysaccharide-induced oxidative stress, tight junction damage and intestinal inflammatory response in yellow catfish, Pelteobagrus fulvidraco

The present study explored the possible mitigative effects of vitamin D₃ (VD₃) on lipopolysaccharide (LPS)-induced intestinal oxidative stress, inflammatory response and tight junction damage in yellow catfish, Pelteobagrus fulvidraco. Herein, four experimental groups were established by injecting yellow catfish with NaCl, LPS, VD₃ or LPS plus VD₃. The results showed that LPS induced oxidative stress and that exogenous VD₃ mitigated the adverse effects of LPS. Additionally, LPS suppressed the activity of antioxidant enzymes (Cat, Sod and Gr) and upregulated the mRNA expression of proinflammatory cytokines (Tnf-α, Il-1β, Il-8). Furthermore, the mRNA expression of "fencing" tight junctions (Claudin-1, Claudin-5, Occludin, Zo-1) was downregulated, while that of "pore-forming" tight junctions (Claudin-2, Claudin-12) was upregulated, however no effect on apoptosis genes was observed (p53, Bax, Caspase-3 and Caspase-9). These LPS-induced effects were significantly reversed by pretreatment with VD₃. Taken together, this study suggests that exogenous VD₃ substantially alleviates LPS-induced intestinal inflammation by upregulating antioxidant activity, suppressing inflammation and promoting fencing tight junctions in the intestine.

Calcitriol inhibits COX-1 and COX-2 expressions of renal vasculature in hypertension: Reactive oxygen species involved?

Vitamin D modulates about 3% human gene transcription besides the classical action on calcium/phosphorus homeostasis. The blood pressure-lowing and other protective action on cardiovascular disease have been reported. The present study aims to examine whether COX-1 and COX-2 were implicated in endothelial dysfunction in hypertension and calcitriol, an active form of vitamin D preserved endothelial function through regulating COX expression. Isometric study demonstrated the impaired endothelium-dependent relaxation (EDR) in renal arteries from spontaneously hypertensive rats were reversed by 12 h-calcitriol treatment and COX-1 and COX-2 inhibitors. Combined uses of COX-1 and COX-2 inhibitor induced more improved relaxations. Exaggerated expressions of COX-1 and COX-2 in renal artery from SHR were inhibited by 12 h-administration of calcitriol, NADPH oxidase inhibitor DPI, or reactive oxygen species (ROS) scavenger tempol. Furthermore, in normotensive WKY rats, calcitriol prevents against the blunted EDR in renal arteries by 12 h-Ang II exposure, with similar improvements by COX-1 and COX-2 inhibitors. Accordingly, increased COX-1 and COX-2 expressions by Ang II exposure were corrected by losartan, DPI, or tempol. Studies on human renal artery also revealed the beneficial action of calcitriol is mediated by suppressing COX-1 and COX-2 expressions, dependent on vitamin D receptor (VDR) activation. Taken together, our findings showed that COX-1 and COX-2 are positively involved in the renovascular dysfunction in hypertension and via VDR, calcitriol benefits renovasular function by suppressing COX-1 and COX-2 expressions. Furthermore, ROS is involved in the COX-1 and COX-2 up-regulations of renal arteries, maybe serving as a mediator in the inhibitory action of calcitriol on COX expression.

Neuroprotective effect of paricalcitol in a rat model of transient global cerebral ischemia

Background

Paricalcitol is known to attenuate ischemic-reperfusion injury of various organs. However, it is not known whether paricalcitol prevents neuronal injury after global cerebral ischemia. The purpose of this study is to investigate the neuroprotective effect of paricalcitol in a rat model of transient global cerebral ischemia.

Methods

This is a prospective, randomized experimental study. Male Sprague-Dawley rats that survived 10 min of four-vessel occlusion were randomly assigned to two treatment groups: one group was treated with paricalcitol 1 μg/kg IP, and the other was given an equivalent volume of normal saline IP. Drugs were administered at 5 min, 1 day, 2 days, and 3 days after ischemia. Neurologic function was assessed at 2 h, 1 day, 2 days, 3 days, and 4 days after ischemia. We tested motor function 3 days after ischemia using the rotarod test. Also, we tested memory function 4 days after ischemia using the passive avoidance test. We assessed neuronal degeneration in the hippocampus of surviving rats 4 days after ischemia.

Results

Eight rats were allocated to each group. No significant differences were found between the groups in terms of survival rate, motor coordination, or memory function. The neurological function score 2-h post-ischemia was significantly higher in the paricalcitol group (p = 0.04). Neuronal degeneration was significantly less in the paricalcitol group compared with the control group (p = 0.01).

Conclusions

Paricalcitol significantly attenuated neuronal injury in the hippocampus. Although motor coordination, memory function, and survival rate were not significantly improved by paricalcitol treatment in this study, paricalcitol remains a potential neuroprotective drug after global cerebral ischemia.

Insights on Nutrients as Analgesics in Chronic Pain

Many serious inflammatory disorders and nutrient deficiencies induce chronic pain, and anti-inflammatory diets have been applied successfully to modify the inflammatory symptoms causing chronic pain. Numerous scientific data and clinical investigations have demonstrated that long-term inflammation could lead to an inappropriate or exaggerated sensibility to pain. In addition, some Non-steroidal Anti-inflammatory Drugs (NSAID), which directly act on the many enzymes involved in pain and inflammation, including cyclooxygenases, are used to dampen the algesic signal to the central nervous system, reducing the responses of soft C-fibers to pain stimuli. On the other hand, there are a few reports from both health authorities and physicians, reporting that decreased transmission of pain signals can be achieved and improved, depending on the patient's dietary habit. Many nutrients, as well as a suitable level of exercise (resistance training), are the best methods for improving the total mitochondrial capacity in muscle cells, which can lead to a reduction in sensitivity to pain, particularly by lowering the inflammatory signaling to C-fibers. According to the current literature, it could be proposed that chronic pain results from the changed ratio of neuropeptides, hormones, and poor nutritional status, often related to an underlying inflammatory disorder. The current review also evaluates the effective role of nutrition-related interventions on the severity of chronic pain. This review pointed out that nutritional interventions can have a positive effect on pain experience through the indirect inhibitory effect on prostaglandin E2 and attenuation of mitochondrial dysfunction caused by ischemia/reperfusion in skeletal muscle, improving the intracellular antioxidant defense system. These data highlight the need for more nutrition studies where chronic pain is the primary outcome, using accurate interventions. To date, no nutritional recommendation for chronic pain has been officially proposed. Therefore, the goal of this article is to explore pain management and pain modulation, searching for a mode of nutrition efficient in reducing pain.

Genetic Variations in VDR could Modulate the Efficacy of Vitamin D3 Supplementation on Inflammatory Markers and Total Antioxidant Capacity among Breast Cancer Women: A Randomized Double Blind Controlled Trial

Background:

Low levels of vitamin D are found in a great part of breast cancer women. Study subjects using vitamin D₃ supplement had lower rates of cancers and fewer markers of inflammation. Additionally, recent studies demonstrate the power of vitamin D supplementation to lower inflammation and oxidative stress biomarkers associate with VDR polymorphism to reduce inflammation. This study was aimed to assess the impact of vitamin D₃ supplementation on the serum concentration of inflammatory markers and antioxidant capacity with regard to VDR polymorphism in the VDR gene in breast cancer women.

Methods:

A randomized, double-blind, placebo-controlled trial was conducted on 56 breast cancer women. Participants were assigned to 2 treatment arms: placebo and vitamin D₃ for 2 months intervention. Supplementation group received 50,000 IU of vitamin weekly. Blood samples were collected at baseline and after the intervention to measure the 25(OH) D₃, TNF-α, TGF- β and TAC. Genotyping was performed for FokI, BsmI, ApaI, and TaqI polymorphism.

Results:

After eight weeks supplementation, the intervention group showed a significant increase in the serum concentration of 25(OH) D₃ (28±2.6 to 39±3.5; p=0.004 and TAC (48.9±13.3 to 63.5±13.3; p= 0.017). Changes in TNF-α, TGF- β1 were not significant. Serum TAC levels of participants with the TT/Tt, Ff genotypes were more responsive to supplementation.

Conclusions:

Supplementation with a vitamin D₃ increased the TAC in breast cancer women, although it had no effect on inflammatory markers. Serum TAC in the TT/Tt, Ff were more responsive to vitamin D supplement compared with those with the FF/ff and tt genotypes.

Effects of Vitamin D3 on the NADPH Oxidase and Matrix Metalloproteinase 9 in an Animal Model of Global Cerebral Ischemia

Decreased blood flow in the brain leads to a rapid increase in reactive oxygen species (ROS). NADPH oxidase (NOX) is an enzyme family that has the physiological function to produce ROS. NOX2 and NOX4 overexpression is associated with aggravated ischemic injury, while NOX2/4-deficient mice had reduced stroke size. Dysregulation of matrix metalloproteinases (MMPs) contributes to tissue damage. The active form of vitamin D3 expresses neuroprotective, immunomodulatory, and anti-inflammatory effects in the CNS. The present study examines the effects of the vitamin D3 pretreatment on the oxidative stress parameters and the expression of NOX subunits, MMP9, microglial marker Iba1, and vitamin D receptor (VDR), in the cortex and hippocampus of Mongolian gerbils subjected to ten minutes of global cerebral ischemia, followed by 24 hours of reperfusion. The ischemia/reperfusion procedure has induced oxidative stress, changes in the expression of NOX2 subunits and MMP9 in the brain, and increased MMP9 activity in the serum of experimental animals. Pretreatment with vitamin D3 was especially effective on NOX2 subunits, MMP9, and the level of malondialdehyde and superoxide anion. These results outline the significance of the NOX and MMP9 investigation in brain ischemia and the importance of adequate vitamin D supplementation in ameliorating the injury caused by I/R.

Repurposing and repositioning neurosteroids in the treatment of traumatic brain injury: A report from the trenches

The field of neuroprotection after brain injuries has been littered with failed clinical trials. Finding a safe and effective treatment for acute traumatic brain injury remains a serious unmet medical need. Repurposing drugs that have been in use for other disorders is receiving increasing attention as a strategy to move candidate drugs more quickly to trial while reducing the very high cost of new drug development. This paper describes our own serendipitous discovery of progesterone's neuroprotective potential, and the strategies we are using in repurposing and developing this hormone for use in brain injuries-applications very different from its classical uses in treating disorders of the reproductive system. We have been screening and testing a novel analog that maintains progesterone's therapeutic properties while overcoming its physiochemical challenges, and testing progesterone in combination treatment with another pleiotropic hormone, vitamin D. Finally, our paper, in the context of the problems and pitfalls we have encountered, surveys some of the factors we found to be critical in the clinical translation of repurposed drugs. This article is part of the Special Issue entitled 'Drug Repurposing: old molecules, new ways to fast track drug discovery and development for CNS disorders'.

The Role of Parathyroid Hormone and Vitamin D Serum Concentrations in Patients with Cardiovascular Diseases

25-hydroxyvitamin D (25(OH)D) plays a crucial role in human homeostasis. Its deficiency (vitamin D deficiency—VDD), being common in European population, combined with elevated concentration of parathyroid hormone (PTH), represents a vicious cycle of mechanisms leading to heart failure (HF). Despite several papers published in that field, the effect of VDD and PTH concentration on cardiovascular system remains unequivocal; thus, the aim of the study was to compare these data among HF and non-HF patients being prospectively enrolled into the study during hospital stay in the cardiology ward. Patients with HF had higher PTH concentration (85.0 ± 52.6 versus 64.5 ± 31.7, p ≤ 0.02) compared to non-HF patients. Mean PTH values were associated with the clinical status expressed by the New York Heart Association class (NYHA class) (“0”—66.04, “I”—56.57, “II”—72.30, “III”—85.59, and “IV”—144.37 pg/ml, p ≤ 0.00004). Interestingly, neither 25(OH)D (31.5 versus 29.7 ng/ml, p ≤ ns) nor phosphorus (P) (1.23 versus 1.18 mmol/l, p ≤ ns) nor total calcium (Ca²⁺) concentration (2.33 versus 2.37 mmol/l, p ≤ ns) differed among the groups. Reassuming PTH serum concentration in contrary to 25(OH)D, P and Ca²⁺ are significantly raised among the patients with HF and shows significant relationship with the clinical status expressed by the NYHA class.

Vitamin D and Its Role in Neonatal Hypoxic-Ischemic Brain Injury

Emerging evidence has demonstrated that vitamin D plays an important role in many adult neurologic disorders, but is also critical in neuronal development and pruning in the neonatal and pediatric populations. Neonates are at a particularly high risk of vitamin D deficiency, in part due to the high prevalence of maternal deficiency during pregnancy. Several preclinical studies have demonstrated that infants born to vitamin D-deficient mothers are at a high risk of developing neonatal brain injury, and recent clinical studies have shown that neonates with hypoxic-ischemic encephalopathy (HIE) tend to be vitamin D-deficient. There are limited data, however, on whether additional prenatal or postnatal supplementation may alter the prevalence or severity of neonatal HIE. This review examines the current data supporting the neuroprotective role of vitamin D, with a focus on how these findings may be translated to neonates with HIE.

The vitamin D analogue paricalcitol attenuates hepatic ischemia/reperfusion injury through down-regulation of Toll-like receptor 4 signaling in rats

INTRODUCTION

Recent studies have revealed that vitamin D and its synthetic analogues have a protective effect on experimental ischemia/reperfusion (I/R) models in several organs, but little is known about its effect on the liver. The aim of this study was to evaluate the beneficial effects of vitamin D in a model of liver I/R in rats, focusing on Toll-like receptor (TLR) 4 signaling, which has been shown to be involved in I/R injury.

MATERIAL AND METHODS

Twenty-four male Wistar rats were randomized into four groups: Saline + Sham, Saline + I/R, Paricalcitol + Sham, and Paricalcitol + I/R. A synthetic vitamin D₂ analogue, paricalcitol, was intraperitoneally injected 24 h prior to surgery. The animals were subjected to 60 min of partial warm ischemia (70%), followed by reperfusion for 6 h on the same day. The ischemic lobe of the liver and blood were collected for molecular biochemical analyses.

RESULTS

Liver damage following I/R was diminished by pretreatment with paricalcitol. Pretreatment with paricalcitol decreased the levels of pro-inflammatory mediators, such as interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and macrophage migration inhibitory factor (MIF), in both plasma and liver tissue. In addition, pretreatment with paricalcitol markedly down-regulated the expression of TLR4, HMGB1, TNF-α and NF-κB.

CONCLUSIONS

The vitamin D analogue paricalcitol attenuates hepatic I/R injury through down-regulation of the TLR4 signaling pathway and might be considered to be a potential nutritional therapeutic agent against I/R injury in the liver.

Calcium-Vitamin D Co-supplementation Affects Metabolic Profiles, but not Pregnancy Outcomes, in Healthy Pregnant Women

BACKGROUND

Pregnancy is associated with unfavorable metabolic profile, which might in turn result in adverse pregnancy outcomes. The current study was designed to evaluate the effects of calcium plus Vitamin D administration on metabolic status and pregnancy outcomes in healthy pregnant women.

METHODS

This randomized double-blind placebo-controlled clinical trial was performed among 42 pregnant women aged 18-40 years who were at week 25 of gestation. Subjects were randomly allocated to consume either 500 mg calcium-200 IU cholecalciferol supplements (n = 21) or placebo (n = 21) for 9 weeks. Blood samples were obtained at the onset of the study and after 9-week trial to determine related markers. Post-delivery, the newborn's weight, length, and head circumference were measured during the first 24 h after birth.

RESULTS

Consumption of calcium-Vitamin D co-supplements resulted in a significant reduction of serum high-sensitivity C-reactive protein levels compared with placebo (-1856.8 ± 2657.7 vs. 707.1 ± 3139.4 μg/mL, P = 0.006). We also found a significant elevation of plasma total antioxidant capacity (89.3 ± 118.0 vs. -9.4 ± 164.9 mmol/L, P = 0.03), serum 25-hydroxyvitamin D (2.5 ± 3.5 vs. -1.7 ± 1.7 ng/mL, P < 0.0001), and calcium levels (0.6 ± 0.6 vs. -0.1 ± 0.4 mg/dL, P < 0.0001). The supplementation led to a significant decrease in diastolic blood pressure (-1.9 ± 8.3 vs. 3.1 ± 5.2 mmHg, P = 0.02) compared with placebo. No significant effect of calcium-Vitamin D co-supplements was seen on other metabolic profiles. We saw no significant change of the co-supplementation on pregnancy outcomes as well.

CONCLUSIONS

Although calcium-Vitamin D co-supplementation for 9 weeks in pregnant women resulted in improved metabolic profiles, it did not affect pregnancy outcomes.

Calcium plus vitamin D supplementation influences biomarkers of inflammation and oxidative stress in overweight and vitamin D-deficient women with polycystic ovary syndrome: a randomized double-blind placebo-controlled clinical trial

OBJECTIVE

This study was conducted to determine the effects of calcium plus vitamin D supplementation on inflammatory factors and biomarkers of oxidative stress among overweight vitamin D-deficient women with polycystic ovary syndrome (PCOS).

DESIGN, PATIENTS AND MEASUREMENTS

This randomized double-blind placebo-controlled clinical trial was performed among 104 overweight vitamin D-deficient women diagnosed with PCOS aged 18-40 years. Participants were randomly divided into four groups. Group A received 1000 mg calcium daily and vitamin D placebo weekly (N = 26), group B 50000 IU vitamin D weekly and calcium placebo daily (N = 26), group C 1000 mg calcium daily plus 50000 IU vitamin D weekly (N = 26) and group D calcium placebo daily plus vitamin D placebo weekly (N = 26) for 8 weeks. Fasting blood samples were taken at baseline and 8 weeks after intervention to measure inflammatory factors and biomarkers of oxidative stress.

RESULTS

After 8 weeks, individuals taking calcium plus vitamin D supplements had greater decreases in homoeostatic model assessment beta-cell function (HOMA-B) score (-11·1 vs -8·6, -3·4 and 13·7, respectively, P = 0·03), serum high-sensitivity C-reactive protein (hs-CRP) (-948·3 vs 802·3, -383·8 and 618·2 ng/ml, respectively, P = 0·04) and plasma malondialdehyde (MDA) concentrations (-0·6 vs -0·5, -0·1 and 0·6 μmol/l, respectively, P = 0·009), and significant increases in plasma total antioxidant capacity (TAC) (35·2 vs 21·1, 22·5 and -153·8 mmol/l, respectively, P = 0·006) and glutathione (GSH) levels (216·0 vs 3·9, -47·5 and -160·8 μmol/l, respectively, P = 0·001) compared with calcium alone, vitamin D alone and placebo groups. Calcium plus vitamin D cosupplementation did not influence plasma NO and catalase levels.

CONCLUSIONS

We found that calcium plus vitamin D cosupplementation for 8 weeks among overweight and vitamin D-deficient women with PCOS had beneficial effects on inflammatory factor and biomarkers of oxidative stress.

Vitamin C Attenuates Isoflurane-Induced Caspase-3 Activation and Cognitive Impairment

Anesthetic isoflurane has been reported to induce caspase-3 activation. The underlying mechanism(s) and targeted intervention(s), however, remain largely to be determined. Vitamin C (VitC) inhibits oxidative stress and apoptosis. We therefore employed VitC to further determine the up-stream mechanisms and the down-stream consequences of the isoflurane-induced caspase-3 activation. H4 human neuroglioma cells overexpressed human amyloid precursor protein (H4-APP cells) and rat neuroblastoma cells were treated either with (1) 2% isoflurane or (2) with the control condition, plus saline or 400 μM VitC for 3 or 6 h. Western blot analysis and fluorescence assay were utilized at the end of the experiments to determine caspase-3 activation, levels of reactive oxygen species and ATP, and mitochondrial function. The interaction of isoflurane (1.4% for 2 h) and VitC (100 mg/kg) on cognitive function in mice was also assessed in the fear conditioning system. Here, we show for the first time that the VitC treatment attenuated the isoflurane-induced caspase-3 activation. Moreover, VitC mitigated the isoflurane-induced increases in the levels of reactive oxygen species, opening of mitochondrial permeability transition pore, reduction in mitochondrial membrane potential, and the reduction in ATP levels in the cells. Finally, VitC ameliorated the isoflurane-induced cognitive impairment in the mice. Pending confirmation from future studies, these results suggested that VitC attenuated the isoflurane-induced caspase-3 activation and cognitive impairment by inhibiting the isoflurane-induced oxidative stress, mitochondrial dysfunction, and reduction in ATP levels. These findings would promote further research into the underlying mechanisms and targeted interventions of anesthesia neurotoxicity.

Effects of calcium-vitamin D co-supplementation on glycaemic control, inflammation and oxidative stress in gestational diabetes: a randomised placebo-controlled trial

AIMS/HYPOTHESIS

This study was designed to assess the effects of calcium and vitamin D supplementation on the metabolic status of pregnant women with gestational diabetes mellitus (GDM).

METHODS

This randomised placebo-controlled trial was performed at maternity clinics affiliated to Kashan University of Medical Sciences, Kashan, Iran. Participants were 56 women with GDM at 24-28 weeks' gestation (18 to 40 years of age). Subjects were randomly assigned to receive calcium plus vitamin D supplements or placebo. All study participants were blinded to group assignment. Individuals in the calcium-vitamin D group (n = 28) received 1,000 mg calcium per day and a 50,000 U vitamin D3 pearl twice during the study (at study baseline and on day 21 of the intervention), and those in the placebo group (n = 28) received two placebos at the mentioned times. Fasting blood samples were taken at study baseline and after 6 weeks of intervention.

RESULTS

The study was completed by 51 participants (calcium-vitamin D n = 25, placebo n = 26). However, as the analysis was based on an intention-to-treat approach, all 56 women with GDM (28 in each group) were included in the final analysis. After the administration of calcium plus vitamin D supplements, we observed a significant reduction in fasting plasma glucose (-0.89 ± 0.69 vs +0.26 ± 0.92 mmol/l, p < 0.001), serum insulin levels (-13.55 ± 35.25 vs +9.17 ± 38.50 pmol/l, p = 0.02) and HOMA-IR (-0.91 ± 1.18 vs +0.63 ± 2.01, p = 0.001) and a significant increase in QUICKI (+0.02 ± 0.03 vs -0.002 ± 0.02, p = 0.003) compared with placebo. In addition, a significant reduction in serum LDL-cholesterol (-0.23 ± 0.79 vs +0.26 ± 0.74 mmol/l, p = 0.02) and total cholesterol: HDL-cholesterol ratio (-0.49 ± 1.09 vs +0.18 ± 0.37, p = 0.003) and a significant elevation in HDL-cholesterol levels (+0.15 ± 0.25 vs -0.02 ± 0.24 mmol/l, p = 0.01) was seen after intervention in the calcium-vitamin D group compared with placebo. In addition, calcium plus vitamin D supplementation resulted in a significant increase in GSH (+51.14 ± 131.64 vs -47.27 ± 203.63 μmol/l, p = 0.03) and prevented a rise in MDA levels (+0.06 ± 0.66 vs +0.93 ± 2.00 μmol/l, p = 0.03) compared with placebo.

CONCLUSIONS/INTERPRETATION

Calcium plus vitamin D supplementation in women with GDM had beneficial effects on their metabolic profile.

TRIAL REGISTRATION

www.irct.ir IRCT201311205623N11.

FUNDING

The study was supported by a grant (no. 92110) from Kashan University of Medical Sciences.

Serum 25-hydroxyvitamin D predicts the short-term outcomes of Chinese patients with acute ischaemic stroke

Low vitamin D levels have been reported to contribute to the risk of cardiovascular events and mortality, especially stroke. In the present study we therefore evaluated the short-term prognostic value of serum 25(OH)D (25-hydroxyvitamin D) in Chinese patients with AIS (acute ischaemic stroke). From February 2010 to September 2012, consecutive stroke patients admitted to the emergency department at two hospitals in Beijing, China were identified. Clinical information was collected, and the serum concentration of 25(OH)D and NIHSS (National Institutes of Health Stroke Scale) were measured at the time of admission. Short-term functional outcome was measured using a modified Rankin Scale (mRS) at 90 days after admission. Multivariate analyses were performed using logistic regression models. During the inclusion period, 231 patients were diagnosed as having AIS, and 220 completed follow-up. The median serum 25(OH)D level was significantly lower in patients with AIS compared with normal controls [14.2 (10.2-18.9) ng/ml compared with 17.9 (12.5-22.9) ng/ml; P<0.001; values are medians (interquartile range)]. 25(OH)D was an independent prognostic marker of short-term functional outcome and death {0.79 (0.73-0.85) and 0.70 (0.50-0.98) respectively [values are odds rations (95% confidence intervals)]; P<0.01 for both, adjusted for NHISS, other predictors and vascular risk factors} in patients with AIS. In ROC (receiver operating characteristic) curve analysis, the prognostic accuracy of 25(OH)D was higher compared with all of the other serum predictors and was in the range of NIHSS score. In conclusion, these findings suggest that 25(OH)D is an independent prognostic marker for death and functional outcome within 90 days in Chinese patients with AIS even after adjusting for possible confounding factors.

Effects of vitamin D supplementation on glucose metabolism, lipid concentrations, inflammation, and oxidative stress in gestational diabetes: a double-blind randomized controlled clinical trial

BACKGROUND

To our knowledge, there is no study that has examined the effects of vitamin D supplementation on metabolic status in gestational diabetes mellitus (GDM).

OBJECTIVE

This study was designed to assess the effects of vitamin D supplementation on metabolic profiles, high-sensitivity C-reactive protein, and biomarkers of oxidative stress in pregnant women with GDM.

DESIGN

This randomized, double-blind, placebo-controlled clinical trial was conducted in 54 women with GDM. Subjects were randomly assigned to receive either vitamin D supplements or placebo. Individuals in the vitamin D group (n = 27) received capsules containing 50,000 IU vitamin D₃ 2 times during the study (at baseline and at day 21 of the intervention) and those in the placebo group (n = 27) received 2 placebos at the same times. Fasting blood samples were collected at baseline and after 6 wk of the intervention to quantify relevant variables.

RESULTS

Cholecalciferol supplementation resulted in increased serum 25-hydroxyvitamin D concentrations compared with placebo (+18.5 ± 20.4 compared with +0.5 ± 6.1 ng/mL; P < 0.001). Furthermore, intake of vitamin D supplements led to a significant decrease in concentrations of fasting plasma glucose (-17.1 ± 14.8 compared with -0.9 ± 16.6 mg/dL; P < 0.001) and serum insulin (-3.08 ± 6.62 compared with +1.34 ± 6.51 μIU/mL; P = 0.01) and homeostasis model of assessment-insulin resistance (-1.28 ± 1.41 compared with +0.34 ± 1.79; P < 0.001) and a significant increase in the Quantitative Insulin Sensitivity Check Index (+0.03 ± 0.03 compared with -0.001 ± 0.02; P = 0.003) compared with placebo. A significant reduction in concentrations of total (-11.0 ± 23.5 compared with +9.5 ± 36.5 mg/dL; P = 0.01) and low-density lipoprotein (LDL) (-10.8 ± 22.4 compared with +10.4 ± 28.0 mg/dL; P = 0.003) cholesterol was also seen after vitamin D supplementation.

CONCLUSIONS

Vitamin D supplementation in pregnant women with GDM had beneficial effects on glycemia and total and LDL-cholesterol concentrations but did not affect inflammation and oxidative stress. This trial was registered at www.irct.ir as IRCT201305115623N7.

Vitamin D supplementation affects serum high-sensitivity C-reactive protein, insulin resistance, and biomarkers of oxidative stress in pregnant women

Unfavorable metabolic profiles and oxidative stress in pregnancy are associated with several complications. This study was conducted to determine the effects of vitamin D supplementation on serum concentrations of high-sensitivity C-reactive protein (hs-CRP), metabolic profiles, and biomarkers of oxidative stress in healthy pregnant women. This randomized, double-blind, placebo-controlled clinical trial was conducted in 48 pregnant women aged 18-40 y old at 25 wk of gestation. Participants were randomly assigned to receive either 400 IU/d cholecalciferol supplements (n = 24) or placebo (n = 24) for 9 wk. Fasting blood samples were taken at study baseline and after 9 wk of intervention to quantify serum concentrations of hs-CRP, lipid concentrations, insulin, and biomarkers of oxidative stress. After 9 wk of intervention, the increases in serum 25-hydroxyvitamin D and calcium concentrations were greater in the vitamin D group (+3.7 μg/L and +0.20 mg/dL, respectively) than in the placebo group (-1.2 μg/L and -0.12 mg/dL, respectively; P < 0.001 for both). Vitamin D supplementation resulted in a significant decrease in serum hs-CRP (vitamin D vs. placebo groups: -1.41 vs. +1.50 μg/mL; P-interaction = 0.01) and insulin concentrations (vitamin D vs. placebo groups: -1.0 vs. +2.6 μIU/mL; P-interaction = 0.04) and a significant increase in the Quantitative Insulin Sensitivity Check Index score (vitamin D vs. placebo groups: +0.02 vs. -0.02; P-interaction = 0.006), plasma total antioxidant capacity (vitamin D vs. placebo groups: +152 vs. -20 mmol/L; P-interaction = 0.002), and total glutathione concentrations (vitamin D vs. placebo groups: +205 vs. -32 μmol/L; P-interaction = 0.02) compared with placebo. Intake of vitamin D supplements led to a significant decrease in fasting plasma glucose (vitamin D vs. placebo groups: -0.65 vs. -0.12 mmol/L; P-interaction = 0.01), systolic blood pressure (vitamin D vs. placebo groups: -0.2 vs. +5.5 mm Hg; P-interaction = 0.01), and diastolic blood pressure (vitamin D vs. placebo groups: -0.4 vs. +3.1 mm Hg; P-interaction = 0.01) compared with placebo. In conclusion, vitamin D supplementation for 9 wk among pregnant women has beneficial effects on metabolic status.

Revisiting the timing hypothesis: biomarkers that define the therapeutic window of estrogen for stroke

Significantly extended life expectancy coupled with contemporary sedentary lifestyles and poor nutrition has created a global epidemic of cardiovascular disease and stroke. For women, this issue is complicated by the discrepant outcomes of hormone therapy (HT) for stroke incidence and severity as well as the therapeutic complications for stroke associated with advancing age. Here we propose that the impact of estrogen therapy cannot be considered in isolation, but should include age-related changes in endocrine, immune, and nucleic acid mediators that collaborate with estrogen to produce neuroprotective effects commonly seen in younger, healthier demographics. Due to their role as modulators of ischemic cell death, the post-stroke inflammatory response, and neuronal survival and regeneration, this review proposes that Insulin-like Growth Factor (IGF)-1, Vitamin D, and discrete members of the family of non-coding RNA peptides called microRNAs (miRNAs) may be crucial biochemical markers that help determine the neuroprotective "window" of HT. Specifically, IGF-1 confers neuroprotection in concert with, and independently of, estrogen and failure of the insulin/IGF-1 axis is associated with metabolic disturbances that increase the risk for stroke. Vitamin D and miRNAs regulate and complement IGF-1 mediated function and neuroprotective efficacy via modulation of IGF-1 availability and neural stem cell and immune cell proliferation, differentiation and secretions. Together, age-related decline of these factors differentially affects stroke risk, severity, and outcome, and may provide a novel therapeutic adjunct to traditional HT practices.

Vitamin D deficiency exacerbates experimental stroke injury and dysregulates ischemia-induced inflammation in adult rats

Vitamin D deficiency (VDD) is widespread and considered a risk factor for cardiovascular disease and stroke. Low vitamin D levels are predictive for stroke and more fatal strokes in humans, whereas vitamin D supplements are associated with decreased risk of all-cause mortality. Because VDD occurs with other comorbid conditions that are also independent risk factors for stroke, this study examined the specific effect of VDD on stroke severity in rats. Adult female rats were fed control or VDD diet for 8 wk and were subject to middle cerebral artery occlusion thereafter. The VDD diet reduced circulating vitamin D levels to one fifth (22%) of that observed in rats fed control chow. Cortical and striatal infarct volumes in animals fed VDD diet were significantly larger, and sensorimotor behavioral testing indicated that VDD animals had more severe poststroke behavioral impairment than controls. VDD animals were also found to have significantly lower levels of the neuroprotective hormone IGF-I in plasma and the ischemic hemisphere. Cytokine analysis indicated that VDD significantly reduced IL-1α, IL-1β, IL-2, IL-4, IFN-γ, and IL-10 expression in ischemic brain tissue. However, ischemia-induced IL-6 up-regulation was significantly higher in VDD animals. In a separate experiment, the therapeutic potential of acute vitamin D treatments was evaluated, where animals received vitamin D injections 4 h after stroke and every 24 h thereafter. Acute vitamin D treatment did not improve infarct volume or behavioral performance. Our data indicate that VDD exacerbates stroke severity, involving both a dysregulation of the inflammatory response as well as suppression of known neuroprotectants such as IGF-I.

Preclinical evaluation of postischemic dehydroascorbic Acid administration in a large-animal stroke model

Dehydroascorbic acid (DHA), a blood-brain barrier transportable form of ascorbic acid, confers robust neuroprotection following murine stroke. In an effort to translate this promising neuroprotective strategy into human clinical trial, we evaluated postischemic DHA administration in a large-animal stroke model. Thirty-six adult male baboons were initially randomized to undergo transorbital craniectomy to induce transient cerebral artery occlusion and to receive postischemic dosing of either 500 mg/kg of DHA or vehicle. Primary outcomes included infarct volume, determined by magnetic resonance imaging, as well as neurological function evaluated on the day of sacrifice. The midpoint interim analysis (n = 9 per cohort) revealed that DHA administration did not significantly improve either infarct volume or neurological function. The study was terminated after a determination of statistical futility. We were unable to confirm a neuroprotective effect for postischemic DHA administration in our large-animal model using a dosing scheme that was previously successful in rodents. Further analysis of the efficacy of DHA administration must thus be undertaken prior to clinical translation.

Pretreatment of vitamin D3 ameliorates lung and muscle injury induced by reperfusion of bilateral femoral vessels in a rat model

BACKGROUND

Peripheral arterial occlusive disease (PAOD) is a challenge in peripheral vascular disease. Clinical observations show reperfusion of occluded vessels may cause compartment syndrome or remote organ injury. Less well known is the role of vitamin D3 in tissue injury; therefore, we attempted to determine whether vitamin D3 could alleviate local and remote organ injury induced by reperfusion of occluded vessels in animal models.

METHODS

Twenty-four male Sprague-Dawley rats were randomized into four groups: saline + sham, saline + I/R, vitamin D3 + sham, and vitamin D3 + I/R group. After pretreatment for 5 d, the animals designed to I/R injury were subjected to 3 h of ischemia induced by bilateral femoral arteries clamp, followed by reperfusion of the vessels for 3 h on d 6. Left lung and left anterior tibial muscle tissue were harvested for wet/dry weight ratio and histopathologic analysis. Blood was collected for analysis of urea nitrogen (BUN), creatinine (Cr), aspartate aminotransferase (AST), alanine aminotransferase (ALT), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), ionized calcium levels, and heme oxygenase-1 (HO-1).

RESULTS

Compared with the saline + sham group, there was a significant increase in plasma IL-6 level in both saline + I/R and vitamin D3 + I/R groups and muscle, lung wet/dry weight ratio in the saline + I/R group (P < 0.05). Compared with the saline + I/R group, there was a significant decrease in plasma IL-6 level, muscle and lung wet/dry weight ratio in both vitamin D3 + sham and vitamin D3 + I/R groups, and leukocyte HO-1 expression in vitamin D3 + sham group (P < 0.05). Compared with the vitamin D3 + sham group, there was a significant increase in plasma IL-6 levels in the vitamin D3 + I/R group, and leukocyte HO-1 expression in vitamin D3 + sham group (P < 0.05). BUN, Cr, AST, ALT, TNF-α, ionized calcium levels did not differ significantly among the groups.

CONCLUSIONS

Pretreatment of vitamin D3 ameliorates the systemic IL-6 levels, lung and muscle injury induced by ischemia followed by reperfusion of bilateral occluded vessels in a rat model.