The benefits of Vitamin D in the COVID-19 pandemic: biochemical and immunological mechanisms

In December 2019, a new infectious complication called CoronaVirus Infectious Disease-19, briefly COVID-19, caused by SARS-COV-2, is identified in Wuhan, China. It spread all over the world and became a pandemic. In many individuals who had suffered SARS-COV-2 infection, cytokine storm starts through cytokine overproduction and leads to Acute Respiratory Syndrome (ARS), organ failure, and death. According to the obtained evidence, Vitamin D (VitD) enhances the ACE2/Ang(1-7)/MasR pathway activity, and it also reduces cytokine storms and the ARS risk. Therefore, VitD intake may be beneficial for patients with SARS-COV-2 infection exposed to cytokine storm but do not suffer hypotension. In the present review, we have explained the effects of VitD on the renin-angiotensin system (RAS) function and angiotensin-converting enzyme2 (ACE2) expression. Furthermore, we have reviewed the biochemical and immunological effects of VitD on immune function in the underlying diseases and its role in the COVID-19 pandemic.

Effects of the Vitamin D3 on Alleviating the Oxidative Stress Induced by Diquat in Wenchang Chickens

Vitamin D₃ (VD₃) is an indispensable micronutrient in livestock and poultry feed. Its function in antioxidant stress has been reported. We investigate whether the addition of different concentrations of VD₃ to the diet affects the production performance, slaughter performance, meat quality, organ index, and gut injury on the diquat (DQ)-induced model of oxidative stress in Wenchang chickens. Four hundred and eighty one-day-old chickens were randomly divided into six groups: control (basal diet), 4000 VD (basal diet + VD₃ 4000 IU per kg feed intake), 1000 VD+DI (DQ, basal diet + VD₃ 1000 IU per kg feed intake), 2000 VD+DI (DQ, basal diet + VD₃ 2000 IU per kg feed intake), and 4000 VD+DI (DQ, basal diet + VD₃ 4000 IU per kg feed intake). The results showed that the addition of VD₃ to the diet promoted DQ-induced weight loss and reduced ADFI, slaughter rate, splenic index, and pH after 1 h and 24 h in the leg muscles. VD₃ decreased the increase in content of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) among proinflammatory cytokines (p < 0.05) and increased the reduction in anti-inflammatory cytokines content of interleukin-10 (IL-10) (p < 0.05) induced by DQ. In addition, liver and kidney injury biomarkers and the intestinal permeability index in serum were disordered after treatment with DQ (p < 0.05). VD₃ perfected the increase of D-lactic acid (D-LA), diamine oxidase (DAO), total cholesterol (T-CHO), creatinine (CR), blood urea nitrogen (BUN), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) content, aspartate transaminase (AST), alanine transaminase (ALT), and lactate dehydrogenase (LDH) activity (p < 0.05); it increased the decrease of albumin (ALB) content (p < 0.05). Meanwhile, VD₃ regulated the intestinal morphology and intestinal barrier. Moreover, DQ induced a decrease in total antioxidant capacity and antioxidant enzyme activity in the serum, liver, and jejunum (p < 0.05), and an increase in malonaldehyde (MDA) content (p < 0.05). However, the addition of different levels of VD₃ could alleviate the above phenomenon of oxidative stress in Wenchang chickens to different degrees. Thus, this research suggested that the addition of VD₃ can relieve the DQ-induced oxidative stress of Wenchang chickens, and the level of VD₃ acquisition is positively correlated with the remission effect.

Association of serum vitamin D status with gestational diabetes mellitus and other laboratory parameters in early pregnant women

Background

The association between serum 25-hydroxy vitamin D (25(OH)D) status and gestational diabetes mellitus (GDM) gained attention in recent years, however the conclusion is still controversial due to many interfering factors, such as region of living, environment, lifestyle, and food supplements. Other metabolites (laboratory parameters) are also important in reflecting gestational states. This study aimed to investigate the association of serum 25(OH)D status in early pregnancy with GDM and other laboratory parameters in pregnant women.

Methods

A total of 1516 pregnant women whose blood glucose were normal before pregnancy in the city of Foshan in Guangdong, China were enrolled in this study. GDM was diagnosed between 24 to 28 weeks of pregnancy following the guidelines from the American Diabetes Association. Maternal serum 25(OH)D and other laboratory parameters—including hematology, coagulation, chemistry, and bone density—were measured utilizing various analytical methods in clinical laboratory at gestational weeks 11 to 14.

Results

The average 25(OH)D concentration was 59.1 ± 12.6 nmol/L. None of the study subjects had 25(OH)D < 25 nmol/L; 434 (28.6%) women had 25(OH)D deficiency (< 50 nmol/L), 882 women (58.2%) had 25(OH)D insufficiency (50–74 mmol/L) and 200 women (13.2%) had 25(OH)D sufficiency (≥ 75 nmol/L). There were 264 (17.4%) women diagnosed with GDM. There was not, however, an association between serum 25(OH)D in early pregnancy and GDM. Interestingly, women with more parity and high serum alkaline phosphatase levels had higher serum 25(OH)D levels. There was a possible positive association between serum 25(OH)D and pre-albumin, and a possible negative association between serum 25(OH)D, creatinine, and thrombin time. This study did not find an association between serum 25(OH)D and bone density.

Conclusions

There were no associations between maternal serum 25(OH)D concentration in early pregnancy and the risk of GDM or bone density. There were, however, correlations between serum 25(OH)D and parity, seasoning at sampling, serum alkaline phosphatase, creatinine, pre-albumin, and coagulation factor thrombin time, which need further study to explain their pathophysiology and clinical significance.

Vitamin D3 enhances the effects of omega-3 oils against metabolic dysfunction-associated fatty liver disease in rat

This study investigated the effects of omega-3 oils (OM) and/or vitamin D₃ (VD) against metabolic dysfunction-associated fatty liver disease (MAFLD). Forty rats were divided into negative (NC) and positive (PC) controls, OM, VD, and OM + VD groups, and MAFLD was induced by high-fat/high-fructose diet (12 weeks). Oral OM (415 mg/kg/day) and/or intramuscular VD (290 IU/kg/day) were given for 4 weeks (5 times/week). The PC animals were markedly obese and had hyperglycemia, insulin resistance, dyslipidemia, elevated liver enzymes, abnormal hepatic histology, and increased caspase-3 with apoptosis than the NC group. The expression of hepatic peroxisome proliferator-activated receptor-α (PPAR-α; 5.3-fold), insulin induced gene-1 (INSIG1; 7.8-fold), adiponectin receptor-1 (AdipoR1; 4.4-fold), and leptin receptor (LEPR; 6-fold) declined, while PPAR-γ (3.7-fold) and sterol regulatory element-binding protein-1 (SREBP1; 2.4-fold) increased, in the PC than the NC group. Leptin (2.2-fold), malondialdehyde (2.1-fold), protein carbonyl groups (17.3-fold), IL-1β (4.4-fold), IL-6 (2.1-fold), TNF-α (1.8-fold) also increased, whereas adiponectin (2.8-fold) glutathione (2.1-fold), glutathione peroxidase-1 (2.4-fold), glutathione reductase (2.2-fold), catalase (1.4-fold), and IL-10 (2.8-fold) decreased, in the PC livers. Both monotherapies attenuated obesity, metabolic profiles, and PPAR-γ/SREBP1/leptin/Caspase-3/apoptosis, while induced PPAR-α/adiponectin/AdipoR1/LEPR/INSIG1. The monotherapies also reduced the oxidative stress and pro-inflammatory markers and increased the antioxidant and anti-inflammatory molecules. However, the OM effects were better than VD monotherapy. Alternatively, the co-therapy group showed the greatest ameliorations in liver functions, lipid-regulatory molecules, oxidative stress, inflammation, and apoptosis. In conclusion, while OM monotherapy was superior to VD, the co-therapy protocol displayed the best alleviations against MAFLD, possibly by enhanced modulation of metabolic, antioxidant, and anti-inflammatory pathways.

Vitamin D3 Protects Mice from Diquat-Induced Oxidative Stress through the NF-κB/Nrf2/HO-1 Signaling Pathway

Vitamin D3, as an indispensable and fat-soluble micronutrient, plays an important role in the health of humans and animals. At present, studies are focusing on the calcium absorption and immunoregulation function of vitamin D3; this study was aimed at exploring the antioxidative stress ability of vitamin D3 on diquat-induced intestinal dysfunction of ICR mice and the underlying mechanism. The results showed that oral gavage of vitamin D3 daily significantly improved the body weight gain and immune organ index and significantly reverted the abnormal changes of ALT, AST, SOD, GSH-Px, T-AOC, and MDA in the serum and jejunum induced by diquat. The addition of vitamin D3 also significantly reduced the concentration of DAO, D-LA, and certain proinflammatory cytokines in serum. Moreover, vitamin D3 improved the pathological morphology of the duodenum, jejunum, colon, liver, and kidney tissues, and it also largely attenuated the degree of inflammatory infiltration of macrophages and cell apoptotic index of jejunal epithelial tissue induced by diquat. The results demonstrated that vitamin D3 significantly recovered the intestinal barrier injury by enhancing the expression of mucins and tight junction proteins in the jejunum. In addition, the results indicated that vitamin D3 could significantly reduce the phosphorylation level of NF-κB (p65) and enhance the expression of Nrf2 and HO-1 in the jejunum compared with the diquat-induced group. This study suggested that oral administration of vitamin D3 can protect mice against oxidative damage by inhibiting the phosphorylation level of NF-κB (p65) and activating Nrf2-related signaling pathways.

Aptamers as potential recognition elements for detection of vitamins and minerals: a systematic and critical review

Background: Vitamin and mineral deficiencies are prevalent globally, and extensive efforts have been made to assess their status. Most traditional methods are expensive and time-consuming; therefore, developments of rapid, simple, specific, and sensitive methods for the assessment of vitamins and minerals in biological samples are of high importance in research. Aptamers are synthetic nucleic acid single-stranded DNA or RNA that can be synthesized in vitro. They can be engineered to be analyte-specific and have been suggested as a substitute for monoclonal antibodies, due to their high sensitivity and affinity. In addition, aptamers can be chemically synthesized and readily modified for use as biosensors. These features make aptamers a promising tool for the detection of biological analytes. In this review, we provide an overview of the potential use of aptamer-based biosensors.Methods: Search terms were conducted on several online databases, including Google Scholar, PubMed, Scopus, and Science Direct from January 2000 to August 2019. Eligibility criteria were used and quality evaluation was performed. Following the review of 4349 articles, 39 articles met the inclusion criteria.Results: Aptasensors have recently been developed for the detection of vitamins by using optical methods, with a detection range from 74 pM to 204 pM, and lower limit of detection of 2.4 pM. Both electrochemical and optical methods have been used for detection of minerals, however electrochemical methods show a wider linear range and lower detection limits compared to optical methods with a wide linear range from 0.2 fM to 1.0 mM and limit of detection of 14.7 fM.Conclusion: The current report reviews recent developments in aptamer-based biosensors for detection of vitamins and minerals. Studies have shown that aptasensors' properties are suitable for the quantification of vitamins and minerals with high sensitivity, affinity, and specificity. Nevertheless, the limitations and future directions of aptamers require further research and new technological innovation.

Vitamin D protects against oxidative stress, inflammation and hepatorenal damage induced by acute paracetamol toxicity in rat

Acute paracetamol (APAP) toxicity is a leading cause of liver, and less commonly renal, injuries through oxidative stress and inflammation. Albeit vitamin D (VD) is a well-known anti-oxidant and anti-inflammatory hormone, there is no report on its potential protective/therapeutic actions against APAP acute toxicity. This study, therefore, measured the interplay between APAP toxicity and the hepatorenal expressions of the VD-metabolising enzymes (Cyp2R1, Cyp27b1 & cyp24a1), receptor (VDR) and binding protein (VDBP) alongside the effects of VD treatment on APAP-induced hepatorenal injuries. Thirty-two male rats were distributed equally into negative (NC) and positive (PC) controls besides VD prophylactic (P-VD) and therapeutic (T-VD) groups. All groups, except the NC, received a single oral dose of APAP (1200 mg/kg). The P-VD also received by intraperitoneal injection two cycles of VD₃ (1000 IU/Kg/day; 5 days/week) prior to, and a third round after, APAP administration. Similarly, the T-VD group received VD₃ (3000 IU/Kg/day) for five successive days post-APAP intoxication. Euthanasia was on the sixth day post-APAP toxicity. The PC group had marked alterations in the hepatorenal biochemical parameters, upregulation in cellular cleaved caspase-3 as well as pronounced increase in the numbers of apoptotic/necrotic cells by TUNEL technique. The PC group plasma levels of 25-hydroxyvitamin D (25-OH VD) also declined markedly and coincided with significant inhibitions in the expression of Cyp2R1 and Cyp27b1 enzymes and VDR, whereas the VDBP and Cyp24a1 increased substantially, in the hepatorenal tissues at the gene and protein levels compared with the NC group. Coherently, the lipid peroxidation marker (MDA) and pro-inflammatory cytokines (IL1β, IL6, IL17A, IFN-γ & TNF-α) augmented significantly, while the anti-oxidative markers (GSH, GPx & CAT) and anti-inflammatory cytokines (IL10 & IL22) diminished substantially, in the PC hepatorenal tissues. Both VD regimens alleviated the APAP-induced hepatorenal damages and restored the 25-OH VD levels together with the hepatorenal expression of Cyp2R1, Cyp27b1, Cyp24a1, VDR and VDBP. Additionally, MDA and all the targeted pro-inflammatory cytokines declined, whereas all the anti-oxidative and anti-inflammatory markers increased, in both VD groups hepatorenal tissues and the results were significantly different than the PC group. Although the P-VD anti-inflammatory and anti-oxidative stress actions were more pronounced than the T-VD group, the results remained markedly abnormal than the NC group. In conclusion, this report is the first to reveal that the circulatory VD levels alongside the hepatorenal VD-metabolising enzymes and VDR are pathologically altered following acute APAP toxicity. Moreover, the prophylactic protocol showed better anti-oxidative and anti-inflammatory effects than the therapeutic regimen against APAP-induced hepatorenal injuries.