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

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.

Vitamin D/VDR signaling attenuates lipopolysaccharide‑induced acute lung injury by maintaining the integrity of the pulmonary epithelial barrier

Vitamin D and its receptor have a protective effect on epithelial barriers in various tissues. Low levels of vitamin D are associated with numerous pulmonary diseases, including acute lung injury (ALI) and acute respiratory distress syndrome. The present study investigated whether the vitamin D/vitamin D receptor (VDR) pathway may ameliorate lipopolysaccharide (LPS)-induced ALI through maintaining the integrity of the alveolar epithelial barrier. This was investigated by exposing wild-type (WT) and VDR knockout C57BL/6J mice to LPS, then comparing the healthy and LPS-treated mice lungs and bronchoalveolar lavage fluid (BALF). More specifically, lung histology, mRNA levels of proinflammatory cytokines and chemokines, and protein expression levels of tight junction proteins were determined. In addition, a vitamin D analog (paricalcitol) was administered to WT mice in order to investigate the effect of vitamin D on the alveolar epithelial barrier following exposure to LPS. VDR knockout mice exhibited severe lung injuries (P<0.001), increased alveolar permeability [demonstrated by a higher wet-dry ratio of lung weight (P<0.05), greater expression levels of BALF protein (P<0.001) and fluorescein isothiocyanate-conjugated 4 kDa dextran (P<0.001) leakage into the alveolar space], elevated proinflammatory cytokine and chemokine mRNA levels, as demonstrated by reverse transcription-quantitative polymerase chain reaction (P<0.05), and decreased protein and mRNA expression levels of occludin (P<0.01) and zonula occludens-1 (ZO-1; P<0.01) compared with WT mice. Paricalcitol treatment partially inhibited these pathological changes in WT mice by maintaining the mRNA and protein expression levels of occludin (P<0.01) and ZO-1 (P<0.05). A lack of VDRs in the pulmonary epithelial barrier appeared to compromise its defense, leading to more severe LPS-induced lung injury. Furthermore, vitamin D treatment alleviated LPS-induced lung injury and preserved alveolar barrier function. Therefore vitamin D treatment may present as a potential therapeutic strategy in ALI and acute respiratory distress syndrome.

Attenuation of hyperoxia-induced lung injury in neonatal rats by 1α,25-Dihydroxyvitamin D3

BACKGROUND

Mounting evidence suggests that Toll-like receptor (TLRs) plays an important role in oxidative stress and is implicated in the pathogenesis of hyperoxic lung injury. 1α,25-Dihydroxyvitamin D3 (1,25(OH)2D3), the hormonally active form of vitamin D, not only plays an essential role in mineral balance, but also possesses immunomodulatory and antioxidant properties. Besides, Vitamin D3 is involved in the regulation of TLRs signaling. The present study was designed to investigate whether 1,25(OH)2D3 attenuates hyperoxia-induced lung injury by regulating TLRs signaling in neonatal rats.

METHODS

Pups were divided into four groups: normoxia control group (NC), normoxia plus 1,25(OH)2D3 treatment group (ND), hyperoxia control group (HC), and hyperoxia plus 1,25(OH)2D3 treatment group (HD). Lung tissues were collected for histological examination and detection of mRNA and protein expressions.

RESULTS

Treatment of hyperoxia-exposed animals with 1,25(OH)2D3 resulted in significantly increased body weight and reduced hyperoxia-induced lung injury. Moreover, 1,25(OH)2D3 significantly downregulated the expression of TLR4, NF-κB, and the inflammatory cytokines TNF-α, IL-1β, and IL-6.

CONCLUSIONS

1,25(OH)2D3 could attenuate hyperoxia-induced lung injury in neonatal rats, possibly by regulating TLR4/NF-κB signaling.

Vitamin D ameliorates hepatic ischemic/reperfusion injury in rats

Vitamin D, most commonly associated with the growth and remodeling of bone, has been shown to ameliorate ischemia/reperfusion injury (IRI) in some tissues, yet its underlying mechanism remains elusive. This study was designed to examine the protective effect of vitamin D, if any, against hepatic IRI in rats and the underlying mechanism involved. Adult female Wistar rats were randomly divided into control, sham-operated (sham), ischemia/reperfusion (I/R), and ischemic-reperfused vitamin D-treated (vit D) groups. Rats in the I/R and vit D groups were subjected to partial (70%) hepatic ischemia for 45 min, followed by 1 h of reperfusion. Vitamin D was given to rats orally in a dose of 500 IU/kg daily for 2 weeks before being subjected to I/R. Markers of liver damage, oxidative stress, inflammation and apoptosis were evaluated. Hepatic morphology was also examined. Vit D-treated rats had significantly lower serum levels of alanine aminotransferase, aspartate aminotransferase, and γ glutamyl transferase compared to rats in the I/R group. Also, vit D-treated rats showed a significant decrease in malondialdehyde, interleukin-1 beta, interleukin-6, tumor necrosis factor-α, nuclear factor κB, B cell leukemia/lymphoma 2-associated X protein, cytochrome c, and caspase-3 levels, with higher levels of glutathione peroxidase and B cell lymphoma 2 protein levels in liver tissues compared to I/R rats. Histological examination showed less damaged liver tissues with amelioration of apoptotic signs in the vit D group compared to the I/R group. In conclusion, vitamin D supplementation ameliorates hepatic IRI mostly by alleviating the inflammatory-apoptotic response mediated by the oxidative reperfusion injury insult.

Roles of vitamin D in amyotrophic lateral sclerosis: possible genetic and cellular signaling mechanisms

Evidence suggests that there are aberrations in the vitamin D-endocrine system in subjects with amyotrophic lateral sclerosis (ALS). Here, we review the relationship between vitamin D and ALS. Vitamin D deficiency was reported in patients with ALS. Dietary vitamin D₃ supplementation improves functional capacity in the G93A transgenic mouse model of ALS. Genetic studies have provided an opportunity to identify the proteins that link vitamin D to ALS pathology, including major histocompatibility complex (MHC) class II molecules, toll-like receptors, poly(ADP-ribose) polymerase-1, heme oxygenase-1, and calcium-binding proteins, as well as the reduced form of nicotinamide adenine dinucleotide phosphate. Vitamin D also exerts its effect on ALS through cell-signaling mechanisms, including glutamate, matrix metalloproteinases, mitogen-activated protein kinase pathways, the Wnt/β-catenin signaling pathway, prostaglandins, reactive oxygen species, and nitric oxide synthase.

In conclusion, vitamin D may have a role in ALS. Further investigation of vitamin D in ALS patients is needed.

The role of vitamin D in Alzheimer's disease: possible genetic and cell signaling mechanisms

Alzheimer's disease (AD) is the most common form of dementia in the elderly individuals and is associated with progressive memory loss and cognitive dysfunction. A significant association between AD and low levels of vitamin D has been demonstrated. Furthermore, vitamin D supplements appear to have a beneficial clinical effect on AD by regulating micro-RNA, enhancing toll-like receptors, modulating vascular endothelial factor expression, modulating angiogenin, and advanced glycation end products. Vitamin D also exerts its effects on AD by regulating calcium-sensing receptor expression, enhancing amyloid-β peptides clearance, interleukin 10, downregulating matrix metalloproteinases, upregulating heme oxygenase 1, and suppressing the reduced form of nicotinamide adenine dinucleotide phosphate expression. In conclusion, vitamin D may play a beneficial role in AD. Calcitriol is the best vitamin D supplement for AD, because it is the active form of the vitamin D3 metabolite and modulates inflammatory cytokine expression. Therefore, further investigation of the role of calcitriol in AD is needed.

Lipopolysaccharide-induced lung injury is independent of serum vitamin D concentration

Vitamin D deficiency is increasing in incidence around the world. Vitamin D, a fat-soluble vitamin, has documented effects on the innate and adaptive immune system, including macrophage and T regulatory (Treg) cell function. Since Treg cells are important in acute lung injury resolution, we hypothesized that vitamin D deficiency increases the severity of injury and delays injury resolution in lipopolysaccharide (LPS) induced acute lung injury. Vitamin D deficient mice were generated, using C57BL/6 mice, through diet modification and limited exposure to ultraviolet light. At 8 weeks of age, vitamin D deficient and sufficient mice received 2.5 g/kg of LPS or saline intratracheal. At 1 day, 3 days and 10 days, mice were anesthetized and lung elastance measured. Mice were euthanized and bronchoalveolar lavage fluid, lungs and serum were collected. Ex vivo neutrophil chemotaxis was evaluated, using neutrophils from vitamin D sufficient and deficient mice exposed to the chemoattractants, KC/CXCL1 and C5a, and to bronchoalveolar lavage fluid from LPS-exposed mice. We found no difference in the degree of lung injury. Leukocytes were mildly decreased in the bronchoalveolar fluid of vitamin D deficient mice at 1 day. Ex-vivo, neutrophils from vitamin D deficient mice showed impaired chemotaxis to KC but not to C5a. Vitamin D deficiency modestly impairs neutrophil chemotaxis; however, it does not affect lung injury or its resolution in an LPS model of acute lung injury.