The role of vitamin D in the age of COVID-19: A systematic review and meta-analysis

BACKGROUND

Evidence recommends that vitamin D might be a crucial supportive agent for the immune system, mainly in cytokine response regulation against COVID-19. Hence, we carried out a systematic review and meta-analysis in order to maximise the use of everything that exists about the role of vitamin D in the COVID-19.

METHODS

A systematic search was performed in PubMed, Scopus, Embase and Web of Science up to December 18, 2020. Studies focused on the role of vitamin D in confirmed COVID-19 patients were entered into the systematic review.

RESULTS

Twenty-three studies containing 11 901 participants entered into the meta-analysis. The meta-analysis indicated that 41% of COVID-19 patients were suffering from vitamin D deficiency (95% CI, 29%-55%), and in 42% of patients, levels of vitamin D were insufficient (95% CI, 24%-63%). The serum 25-hydroxyvitamin D concentration was 20.3 ng/mL among all COVID-19 patients (95% CI, 12.1-19.8). The odds of getting infected with SARS-CoV-2 are 3.3 times higher among individuals with vitamin D deficiency (95% CI, 2.5-4.3). The chance of developing severe COVID-19 is about five times higher in patients with vitamin D deficiency (OR: 5.1, 95% CI, 2.6-10.3). There is no significant association between vitamin D status and higher mortality rates (OR: 1.6, 95% CI, 0.5-4.4).

CONCLUSION

This study found that most of the COVID-19 patients were suffering from vitamin D deficiency/insufficiency. Also, there is about three times higher chance of getting infected with SARS-CoV-2 among vitamin-D-deficient individuals and about five times higher probability of developing the severe disease in vitamin-D-deficient patients. Vitamin D deficiency showed no significant association with mortality rates in this population.

The Therapeutic Potential of Quercetin in Parkinson's Disease: Insights into its Molecular and Cellular Regulation

Parkinson's disease (PD) is a chronic and progressive neurodegenerative disorder characterized by the progressive death of dopaminergic neurons in the substantia nigra pars compacta (SNc). PD is a multifactorial disorder, with several different factors being suggested to play a synergistic pathophysiological role, including oxidative stress, autophagy, underlying pro-inflammatory events and neurotransmitters abnormalities. Overall, PD can be viewed as the product of a complex interaction of environmental factors acting on a given genetic background. The importance of this subject has gained more attention to discover novel therapies to prevent as well as treat PD. According to previous research, drugs used to treat PD have indicated significant limitations. Therefore, the role of flavonoids has been extensively studied in PD treatment. Quercetin, a plant flavonol from the flavonoid group, has been considered as a supplemental therapy for PD. Quercetin has pharmacological functions in PD by controlling different molecular pathways. Although few studies intended to evaluate the basis for the use of quercetin in the context of PD have been conducted so far, at present, there is very little evidence available addressing the underlying mechanisms of action. Various principal aspects of these treatment procedures remain unknown. Here, currently existing knowledge supporting the use of quercetin for the clinical management of PD has been reviewed.

Effects of metformin and insulin therapy regimens on postpartum oral glucose tolerance test results in pregnant women with gestational diabetes mellitus: a comparative study

OBJECTIVES

The main purpose of this study was to compare the effects of two regimens of metformin and insulin therapy on postpartum oral glucose tolerance test (OGTT) results in pregnant women with gestational diabetes mellitus (GDM).

METHODS

In this single-blind randomized clinical trial (RCT), a total number of 60 pregnant women meeting the inclusion criteria were assigned to two groups with a randomized block design (RBD): insulin therapy (IT) group (30 patients) and metformin therapy (MT) group (30 patients). At baseline, the data were comprised of prenatal maternal age, gestational age, GDM diagnosis, and maternal weight/height. During the postpartum period, 5-cc blood samples were taken from the pregnant women concerned to analyze their fasting blood sugar (FBS) levels. Then, the patients were asked to come back four days and six weeks later after delivery to check the OGTT results. At six weeks postpartum, in addition to OGTT, the glycated hemoglobin (HbA₁C) test was performed for all mothers. Finally, six weeks after delivery, these mothers were evaluated with regard to weight loss and body mass index (BMI).

RESULTS

Six weeks postpartum, the maternal weight and BMI significantly decreased in the MT group compared with the IT one, while there was no significant difference between both groups at baseline. On the fourth day, the OGTT results in the MT group were significantly lower in comparison with those in the IT group (p=0.012). At sixth weeks postpartum, the OGTT results were comparably lower in the MT group than those reported for the IT one; however, such a difference was not statistically significant (p=0.087).

CONCLUSIONS

According to the study results, metformin could be an effective and safe treatment for pregnant women suffering from GDM instead of insulin therapy.

The effects of vitamin D supplementation on expanded disability status scale in people with multiple sclerosis: A critical, systematic review and metaanalysis of randomized controlled trials

In this meta-analysis of randomized controlled trials (RCTs), the effects of vitamin D supplementation on the scores for the expanded disability status scale (EDSS) in people with multiple sclerosis (MS) are assessed. The following databases were search up to January 2018: MEDLINE, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials. The quality of the relevant extracted data was assessed according to the Cochrane risk of bias tool. Data were pooled by the use of the inverse variance method and expressed as mean difference with 95% Confidence Intervals (95% CI). Six studies were included in this meta-analysis. The findings demonstrated that supplementation with vitamin D alone and vitamin D plus calcium did not affect the EDSS score (WMD -0.11 (-0.33, 0.11); P = 0.32). In addition, subgroup analysis showed that vitamin D supplementation alone, when compared to the use of a placebo, and vitamin D plus calcium supplementation compared with the control did not affect EDSS (WMD -0.13 (-0.30, 0.11); P = 0.29) and (WMD -0.08 (-0.57, 0.41); P = 0.29), respectively. Overall, this meta-analysis indicated that taking vitamin D in people with MS had no significant effect on EDSS.

A Genetic Association Study of MTHFR C677T Polymorphism with Risk of Metabolic Syndrome: A Systematic Review and Meta-Analysis

Methylenetetrahydrofolate reductase (MTHFR) is an enzyme that plays a crucial role as a methyl-group donor in demethylation of homocysteine. The aim of this systematic review and meta-analysis was to study the relationship between MTHFR gene polymorphism and metabolic syndrome (MS). We used search engines and databases such as Science Direct, Google Scholar, Embase, Cochrane Library, and PubMed to identify eligible studies up to 2018. The articles were studied based on keywords including MTHFR, mutation, variant, and polymorphism in combination with MS. Data was analyzed using Comprehensive Meta-Analysis version 2.2.064 software. After extracting the data from seven articles, the total number of subjects was 1280 in the patient group and 1374 in the control group. The odds ratio was estimated to be 1.078 for the allele model of T vs. C (95% confidence interval [CI]: 1.626-0.715), 1.157 for the allele model of CC vs. CT (95% CI: 0.829-1.615), 1.020 for the allele model of CT + TT vs. CC (95% CI: 1.611-0.646) and 0.799 for the allele model of TT vs. CC + CT (95% CI: 1.185- 0.539). As well, the results showed no statistically significant correlation between polymorphism genotypes of the MTHFR gene and MS (P<0.05). In general, this study showed that the presence of C677T polymorphism in the MTHFR gene has no effect on the incidence of MS.

Chemical Decellularization Methods and Its Effects on Extracellular Matrix

Background:  Extracellular matrix (ECM) produced by tissue decellularization processes as a biological scaffold due to its unique properties compared to other scaffolds for migration and implantation of stem cells have been used successfully in the field of tissue engineering and regenerative medicine in the last years. The objective of this manuscript was to provide an overview of the chemical decellularization methods, evaluation of decellularized ECM and the potential effect of the chemical decellularization agents on the biochemical composition.Methods: We searched in Google Scholar, PubMed, Scopus, and Science Direct. The literature search was done by using the following keywords: “ECM, biologic scaffold, decellularization, chemical methods, tissue engineering.” We selected articles have been published from 2000 to 2016, and 15 full texts and 97 abstracts were reviewed.Results:Employing an optimization method to minimize damage to the ECM ultrastructure as for a result of the lack of reduction in mechanical properties and also the preservation of essential proteins such as laminin, fibronectin, Glycosaminoglycans (GAGs), growth factor is required. Various methods include chemical, physical and enzymatic technics were studied. However, on each of these methods can have undesirable effects on ECM.Conclusion: It is suggested that instead of the Sodium dodecyl sulfate (SDS) which have high strength degradation, we can use zwitterionic separately or in combination with SDS. Tributyl phosphate (TBP) due to its unique properties can be used in decellularization process.

Ventricular endomyocardial fibrosis in a pregnant female with Behçet’s disease

A 32-year-old pregnant woman, diagnosed with Behçet’s disease 6 months earlier, presented with recent mild hemoptysis and exertional dyspnea. Transthoracic echocardiography showed an enlarged dysfunctional right ventricle. A large hypoechoic triangular-shaped mass was seen attached to the inner right ventricular wall, filling the cavity. No change in the size of the mass was noted after anticoagulant administration, and right heart failure progressed. Surgery was performed to remove the mass and repair the tricuspid valve. This was a very rare presentation of Behçet’s disease in pregnancy, which resulted in delivery of a completely healthy baby despite corticosteroid pulse therapy and cyclophosphamide.