Vitamin D3 inhibits p38 MAPK and senescence-associated inflammatory mediator secretion by senescent fibroblasts that impacts immune responses during ageing.

Vitamin D3 replacement in older insufficient adults significantly improves their antigen-specific varicella zoster virus (VZV) cutaneous immunity. However, the mechanisms involved in this enhancement of cutaneous immunity are not known. Here, we show for the first time that vitamin D3 blocks the senescence-associated secretory phenotype (SASP) production by senescent fibroblasts by partially inhibiting the p38 MAPK pathway. Furthermore, transcriptomic analysis of skin biopsies from older subjects after vitamin D3 supplementation shows that vitamin D3 inhibits the same inflammatory pathways in response to saline as the specific p38 inhibitor, losmapimod, which also enhances immunity in the skin of older subjects. Vitamin D3 supplementation therefore may enhance immunity during ageing in part by blocking p38 MAPK signalling and in turn inhibit SASP production from senescent cells in vivo.

Circadian regulation of calcium and phosphorus homeostasis during the oviposition cycle in laying hens.

Maintenance of calcium and phosphorus homeostasis in laying hens is crucial for preservation of skeletal integrity and eggshell quality, though physiological regulation of these systems is incompletely defined. To investigate changes in mineral and vitamin D3 homeostasis during the 24-h egg formation cycle, 32-wk-old commercial laying hens were sampled at 1, 3, 4, 6, 7, 8, 12, 15, 18, 21, 23, and 24 h post-oviposition (HPOP; n ≥ 4). Ovum location and egg calcification stage were recorded, and blood chemistry, plasma vitamin D3 metabolites, circulating parathyroid hormone (PTH), and expression of genes mediating uptake and utilization of calcium and phosphorus were evaluated. Elevated levels of renal 25-hydroxylase from 12 to 23 HPOP suggest this tissue might play a role in vitamin D3 25-hydroxylation during eggshell calcification. In shell gland, retinoid-x-receptor gamma upregulation between 6 and 8 HPOP followed by subsequently increased vitamin D receptor indicate that vitamin D3 signaling is important for eggshell calcification. Increased expression of PTH, calcitonin, and fibroblast growth factor 23 (FGF23) receptors in the shell gland between 18 and 24 HPOP suggest elevated sensitivity to these hormones toward the end of eggshell calcification. Shell gland sodium-calcium exchanger 1 was upregulated between 4 and 7 HPOP and plasma membrane calcium ATPase 1 increased throughout eggshell calcification, suggesting the primary calcium transporter may differ according to eggshell calcification stage. Expression in shell gland further indicated that bicarbonate synthesis precedes transport, where genes peaked at 6 to 7 and 12 to 18 HPOP, respectively. Inorganic phosphorus transporter 1 (PiT-1) expression peaked in kidney between 12 and 15 HPOP, likely to excrete excess circulating phosphorus, and in shell gland between 18 and 21 HPOP. Upregulation of FGF23 receptors and PiT-1 during late eggshell calcification suggest shell gland phosphorus uptake is important at this time. Together, these findings identified potentially novel hormonal pathways involved in calcium and phosphorus homeostasis along with associated circadian patterns in gene expression that can be used to devise strategies aimed at improving eggshell and skeletal strength in laying hens.

Dietary Co-supplements attenuate the chronic unpredictable mild stress-induced depression in mice.

Does it make a difference what we eat when it comes to our mental health? Food and nutrients are essential not only for human biology and physical appearance but also for mental and emotional well-being. There has been a significant increase in the favourable effects of dietary supplements in the treatment of depressive state in the latest days. Co-supplements which can be a great contribution in the management of depression from the future perspective and might help to reduce standard anti-depressant drug doses, which can be a strategic way to reduce the side effect of standard anti-depressants drugs. This study was designed to evaluate and compare the anti-depressant effects of cholecalciferol-D3 (V.D3), n-3 polyunsaturated fatty acid (PUFA), and a combination of V.D3 + n-3 PUFA with fluoxetine treatment in chronic unpredictable mild stress (CUMS) induced depression in the mice model. We established CUMS depressant mice model and treated CUMS mice with V.D3, n-3 PUFA, and a combination of V.D3 + n-3 PUFA with fluoxetine. Behavioral changes were measured by the forced swim and tail suspension test. Oxidative stress markers and anti-depressant activity were assessed through parameters such as superoxide dismutase, reduced glutathione, lipid peroxidation, and serum corticosterone levels. Additionally, we measured the levels of neurotransmitters dopamine and serotonin. CUMS induced mice displayed depressive-like behaviours. Moreover, cholecalciferol-D3, n-3 PUFA, and a combination of Cholecalciferol-D3 + n-3 PUFA with fluoxetine treatment attenuated the depressive-like behaviour in CUMS mice accompanied with suppression of oxidative stress markers by up-regulated the expression of an antioxidant signalling pathway. The results suggested that treatment of cholecalciferol-D3, n-3 PUFA, and a combination of Cholecalciferol-D3 + n-3 PUFA with fluoxetine significantly ameliorated depressive-like behaviours in CUMS induced depression in mice. To delve further into the implications of these findings, future studies could explore the specific molecular mechanisms underlying the observed effects on oxidative stress markers and the antioxidant signaling pathway. This could provide valuable insights into the potential of dietary supplements in the management of depression and help in reducing the reliance on conventional antidepressant medications, thus improving the overall quality of treatment for this prevalent mental health condition.

Effect of 25-hydroxycholecalciferol supplementation with different dietary available phosphorus levels for broilers.

1. Based on the hypothesis that 25-hydroxycholecalciferol (25-OH-D3) inclusion would optimise dietary mineral digestibility and ameliorate growth performance and bone mineralisation in available phosphorus (AvP) deficient-fed broilers, a trial was conducted to evaluate its effect on diets with different levels of AvP.2. Broilers aged 1-21 d were randomly assigned one of the eight treatments, consisting of four dietary levels of AvP (0.45%, 0.42%, 0.39%, and 0.36%) and with or without supplementation with 25-OH-D3 at 69 µg/kg of feed. All diets contained 100 µg/kg of vitamin D3 (cholecalciferol).3. The addition of 25-OH-D3 resulted in higher feed intake and body weight gain, and lower FCR (P < 0.05) compared to non-supplemented diets, whereas AvP levels had a quadratic effect only on feed intake. There were no interactions between treatment factors.4. Increasing AvP levels linearly reduced the ileal digestibility of Ca and P (P < 0.01) and supplementing 25-OH-D3 increased both Ca and P ileal digestibility (P < 0.05), without any interactions observed for ileal digestibility.5. There was an interaction, whereby 25-OH-D3 inclusion increased serum metabolites in broilers fed 0.36% to 0.42% AvP compared to the non-supplemented diets (P < 0.001), whereas, at 0.45% AvP, diets with or without 25-OH-D3 had similar results.6. The P content in bone linearly increased in line with AvP levels (P < 0.05) and supplementation of 25-OH-D3 increased ash bone content (P < 0.001).7. Broilers can benefit from 25-OH-D3 supplementation combined with cholecalciferol with regard to Ca and P utilisation and vitamin D status, allowing for a reduction of dietary AvP levels down to 0.36% without impairing growth performance or bone status.

n-3 essential fatty acid and vitamin D supplementation improve skeletal health in laying hens.

Keel bone fractures and osteoporosis are prevalent and damaging skeletal issues in the laying hen industry. There is a large interest in improving bone quality parameters to reduce or eliminate these conditions, thus improving bird welfare. Both essential fatty acids (EFA) and vitamin D can play a role in bone metabolism. The hypothesis of this study was that birds supplemented with lower n-6:n-3 EFA ratio or vitamin D would have improved bone properties compared to a control diet. A total of 3,520 Lohmann Brown-Lite pullets were used in this study. Pullets were housed on the floor from 0 to 17 wk of age and then moved to an aviary (17-52 wk of age). Starting at 12 wk of age, birds were split into diet treatments-control, flax, fish, or vitamin D diets with n-6:n-3 ratios of 6.750, 0.534, 0.534, and 6.750, respectively. Diets were formulated to be isonitrogenous and isocaloric. Basal vitamin D3 levels were formulated to be 2,760 IU/kg across all diets; for the vitamin D diet, the vitamin D3 level was increased to 5,520 IU/kg. Hens on fish and vitamin D diets had greater bone density, keel bone volume, digital bone mineral content, and keel condition compared to flax and control hens. Additionally, birds fed the vitamin D diet had the heaviest body weights compared to birds fed fish or control diets. Birds fed the flax and vitamin D diets had improved feather coverage across multiple body regions. Feeding an n-3 EFA- or vitamin D-enriched diet decreased mortality by 1.6 to 3.3% compared to the control. The fish and vitamin D diets generated mixed production performance. Compared to the other treatments, the vitamin D diet generated higher case weights but lower hen day percentage throughout the study. When compared to the other treatments, the fish diet had the lowest case weights but had a greater hen day percentage after 36 wk of age. Results indicate that a fish-based EFA and vitamin D supplementation show promise in improving skeletal health but require further investigation.

Nephroprotective effect of vitamin D Against Levofloxacin-induced renal injury: an observational study.

The pathogenesis of kidney damage involves complicated interactions between vascular endothelial and tubular cell destruction. Evidence has shown that vitamin D may have anti-inflammatory effects in several models of kidney damage. In this study, we evaluated the effects of synthetic vitamin D on levofloxacin-induced renal injury in rats. Forty-two white Albino rats were divided into six groups, with each group comprising seven rats. Group I served as the control (negative control) and received intraperitoneal injections of normal saline (0.5 ml) once daily for twenty-one days. Group II and Group III were treated with a single intraperitoneal dose of Levofloxacin (50 mg/kg/day) and (100 mg/kg/day), respectively, for 14 days (positive control groups). Group IV served as an additional negative control and received oral administration of vitamin D3 (500 IU/rat/day) for twenty-one days. In Group V, rats were orally administered vitamin D3 (500 IU/rat/day) for twenty-one days, and intraperitoneal injections of Levofloxacin (50 mg/kg/day) were administered on day 8 for 14 days. Group VI received oral vitamin D3 supplementation (500 IU/rat/day) for twenty-one days, followed by intraperitoneal injections of Levofloxacin (100 mg/kg/day) on day 8 for fourteen days. Blood samples were collected to measure creatinine, urea, malondialdehyde, glutathione reductase, and superoxide dismutase levels. Compared to the positive control group, vitamin D supplementation lowered creatinine, urea, and malondialdehyde levels, while increasing glutathione reductase and superoxide dismutase levels. Urea, creatinine, and malondialdehyde levels were significantly (p<0.05) higher in rats administered LFX 50mg and 100mg compared to rats given (LFX + vitamin D). The main findings of this study show that vitamin D reduces renal dysfunction, suggesting that vitamin D has antioxidant properties and may be used to prevent renal injury.

Vitamin D3 decreases myoblast fusion during the growth and increases myogenic gene expression during the differentiation phase in muscle satellite cells from Korean native beef cattle.

The process of myogenesis, which involves the growth and differentiation of muscle cells, is a crucial determinant of meat yield and quality in beef cattle. Essential nutrients, such as vitamins D and A, play vital roles in the development and maintenance of various tissues, including muscle. However, limited knowledge exists regarding the specific effects of vitamins A and D in bovine muscle. Therefore, the aim of this study was to investigate the impact of vitamins A and D treatment on myogenic fusion and differentiation in bovine satellite cells (BSC). BSC were isolated from Korean native beef cattle, specifically from four female cows approximately 30 mo old. These individual cows were used as biological replicates (n = 3 or 4), and we examined the effects of varying concentrations of vitamins A (All-trans retinoic acid; 100 nM) and D (1,25-dihydroxy-vitamin D3; 1 nM, 10 nM, and 100 nM), both individually and in combination, on myoblast fusion and myogenic differentiation during the growth phase (48 h) or differentiation phase (6 d). The results were statistically analyzed using GLM procedure of SAS with Tukey's test and t-tests or one-way ANOVA where appropriate. The findings revealed that vitamin A enhanced the myoblast fusion index, while vitamin D treatment decreased the myoblast fusion index during the growth phase. Furthermore, vitamin A treatment during the differentiation phase promoted terminal differentiation by regulating the expression of myogenic regulatory factors (Myf5, MyoD, MyoG, and Myf6) and inducing myotube hypertrophy compared to the control satellite cells (P < 0.01). In contrast, vitamin D treatment during the differentiation phase enhanced myogenic differentiation by increasing the mRNA expression of MyoG and Myf6 (P < 0.01). Moreover, the combined treatment of vitamins A and D during the growth phase increased myoblast fusion and further promoted myogenic differentiation and hypertrophy of myotubes during the differentiation phase (P < 0.01). These results suggest that vitamin A and D supplementation may have differential effects on muscle development in Korean native beef cattle during the feeding process.

The study investigated the effects of vitamins A and D on the growth and differentiation phases of bovine satellite cells and found that both vitamins have a positive impact on muscle development. Vitamin A promoted myoblast fusion during the growth phase, leading to increased myotube formation, while vitamin D suppressed myoblast fusion during this phase. However, during the differentiation phase, both vitamins enhanced terminal differentiation and hypertrophy. Vitamin A promoted the activation of satellite cells, while vitamin D promoted the expression of genes that enhance myogenesis. The combination treatment of vitamins A and D during the growth phase complemented each other to increase myogenic cell fusion, and during differentiation, promoted terminal differentiation and hypertrophy. These findings suggest that supplementing cattle feed with both vitamins A and D has the potential to enhance muscle development, which would be advantageous for the meat industry.

Increased dietary vitamin D3 and calcium partially alleviate heat stress symptoms and inflammation in lactating Holstein cows independent of dietary concentrations of vitamin E and selenium.

Twelve multiparous Holstein cows (42.2 ± 5.6 kg of milk/d; 83 ± 27 d in milk) were used in a split-plot design testing the effects of mineral and vitamin supplementation on the time course of animal performance, metabolism, and inflammation markers during heat stress. The main plot was the average concentrations of dietary vitamin E and Se (adequate: 11.1 IU/kg of vitamin E and 0.55 mg/kg of Se, and high: 223 IU/kg of vitamin E and 1.8 mg/kg of Se, respectively). Within each plot, cows were randomly assigned to (1) heat stress (HS) with adequate concentrations of vitamin D3 and Ca (1,012 IU/kg and 0.73%, respectively), (2) HS with high concentrations of vitamin D3 and Ca (HS+D3/Ca; 3,764 IU/kg and 0.97%, respectively), or (3) pair-feeding (PF) in thermoneutrality with adequate concentrations of vitamin D3 and Ca (1,012 IU/kg and 0.73% Ca) in a Latin square design with 14-d periods and 7-d washouts. The highest rectal temperature was recorded at 1700 h for HS (39.4°C; mean of d 1 to 14), being 1.2 and 0.8°C greater than for PF and HS+D3/Ca, respectively. Respiratory rate and water intake were higher in HS (73 breaths/min and 115 L/d, respectively) relative to PF (28 breaths/min and 76 L/d). Heat stress decreased dry matter intake progressively, reaching a nadir on d 5 to 7 (33% reduction) and was not different between treatments. Milk yield decreased progressively in all treatments, but remained greater in PF relative to HS from d 3 to 14 (10%), whereas HS and HS+D3/Ca were not different. Milk fat, protein, and lactose concentrations and yields were lower in HS relative to PF from d 3 to 14, but not different between HS and HS+D3/Ca. Relative to PF, preprandial insulin concentrations were increased in HS, whereas plasma nonesterified fatty acids were decreased on d 7 and 14. Plasma lipopolysaccharide-binding protein concentrations increased in HS cows on d 7 and 14, respectively, relative to PF, whereas they were reduced in HS + D3/Ca on d 14. Plasma C-reactive protein, tumor necrosis factor-α, and fecal calprotectin were increased in HS relative to both PF and HS+D3/Ca on d 7 and 14. Rectal temperature was positively associated with plasma lipopolysaccharide-binding protein (r = 0.72), tumor necrosis factor-α (r = 0.74), C-reactive protein (r = 0.87), and with milk somatic cells (r = 0.75). Plasma 8-hydroxy-2-deoxyguanosine concentrations presented a 3-way interaction, where 8-hydroxy-2-deoxyguanosine was lower in HS than in PF on d 7 and 14, and lower in HS+D3/Ca relative to HS on d 14 in the adequate vitamin E and Se treatment, but no effects were observed in the high vitamin E and Se group. Plasma superoxide dismutase concentrations increased over time, and were higher in HS relative to PF on d 14, whereas HS+D3/Ca was similar to HS. Heat stress markedly reduced milk production and milk components while increasing markers of leaky gut and inflammation. In contrast, vitamin D3 and Ca supplementation reduced hyperthermia (d 7-14), markers of leaky gut, and inflammation independent of dietary concentrations of vitamin E and Se.

Antagonizing EZH2 combined with vitamin D3 exerts a synergistic role in anti-fibrosis through bidirectional effects on hepatocytes and hepatic stellate cells.

BACKGROUND AND AIM: Whether vitamin D3 (VD3) supplementation is associated with improved liver fibrosis is controversial. METHODS: Liver fibrosis models were treated with VD3, active VD (1,25-OH2 Vitamin D3), or collaboration with GSK126 (Ezh2 inhibitor), respectively. Hepatic stellate cells (HSCs) were co-cultured with hepatocytes and then stimulated with TGF-ß. Autophagy of hepatocytes was determined after the intervention of 1,25-OH2 Vitamin D3 and GSK126. Also, the active status of HSCs and the mechanism with 1,25-OH2 Vitamin D3 and GSK126 intervention were detected. RESULTS: 1,25-OH2 Vitamin D3, but not VD3, is involved in anti-fibrosis and partially improves liver function, which might be associated with related enzymes and receptors (especially CYP2R1), leading to decreased of its biotransformation. GSK126 plays a synergistic role in anti-fibrosis. The co-culture system showed increased hepatocyte autophagy after HSCs activation. Supplementation with 1,25-OH2 Vitamin D3 or combined GSK126 reduced these effects. Further studies showed that 1,25-OH2 Vitamin D3 promoted H3K27 methylation of DKK1 promoter through VDR/Ezh2 due to the weakening for HSCs inhibitory signal. CONCLUSIONS: VD3 bioactive form 1,25-OH2 Vitamin D3 is responsible for the anti-fibrosis, which might have bidirectional effects on HSCs by regulating histone modification. The inhibitor of Ezh2 plays a synergistic role in this process.

Effect of prepartum source and amount of vitamin D supplementation on lactation performance of dairy cows.

The objectives of this experiment were to determine the effects of supplementing 25-hydroxyvitamin D3 (calcidiol, CAL) compared with vitamin D3 (cholecalciferol, CHOL) at 1 or 3 mg/d in late gestation on production outcomes of dairy cows. One hundred thirty-three parous and 44 nulliparous pregnant Holstein cows were enrolled in the experiment. Cows were blocked by parity and previous lactation milk yield (parous) or genetic merit (nulliparous) and assigned randomly to receive 1 or 3 mg/d of CAL or CHOL in a 2 × 2 factorial arrangement of treatments (CAL1, CAL3, CHOL1, and CHOL3). Treatments were provided to individual cows as a top-dress to the prepartum diet from 250 d in gestation until parturition. The prepartum diet had a dietary cation-anion difference of -128 mEq/kg of dry matter. Production and disease were evaluated for the first 42 d in milk, and reproduction was evaluated to 300 d in milk. Incidence of postpartum diseases did not differ among treatments. Feeding CAL compared with CHOL increased yields of colostrum and colostrum fat, protein, and total solids, resulting in an increased amount of net energy for lactation secreted as colostrum (CHOL = 7.0 vs. CAL = 9.0 ± 0.7 Mcal). An interaction between source and amount was observed for milk yield: CAL3 increased milk yield compared with CHOL3 (CHOL3 = 34.1 vs. CAL3 = 38.7 ± 1.4 kg/d) but milk yield did not differ between CAL1 and CHOL1 (CHOL1 = 36.9 vs. CAL1 = 36.4 ± 1.4 kg/d). Concentrations of serum calcidiol on day of calving and average serum Ca from d 2 to 11 postpartum were positively associated with milk yield in the first 42 d in milk. Interactions between source and amount of vitamin D were also observed for pregnancy after first AI: the percentage of cows receiving CHOL1 and CAL3 that became pregnant was smaller than that of cows receiving CHOL3 and CAL1. However, pregnancy per AI and pregnancy by 300 d in milk did not differ among treatments. Overall, CAL3 increased milk yield compared with CHOL3, whereas in cows fed 1 mg/d (CAL1 and CHOL1), the source of vitamin D generally had no effect. The effect of CAL3 may be explained in part by serum CAL concentrations and postpartum serum Ca, which were associated with milk yield.

Effect of source and amount of vitamin D on serum concentrations and retention of calcium, magnesium, and phosphorus in dairy cows.

The objectives of the experiment were to determine the effects of supplementing 2 amounts of 25-hydroxyvitamin D3 (calcidiol; CAL) compared with equal amounts of vitamin D3 (cholecalciferol; CHOL) on serum concentrations, absorptions, and retentions of Ca, Mg, and P in periparturient dairy cows. One hundred seventy-seven (133 parous and 44 nulliparous) pregnant Holstein cows were enrolled in the experiment. Cows were blocked by parity and previous lactation milk yield (parous) or genetic merit for energy-corrected milk yield (nulliparous) and assigned randomly to receive 1 or 3 mg/d of CAL or CHOL in a 2 × 2 factorial arrangement of treatments. Treatments were provided to individual cows as a top-dress to the prepartum diet from 250 d gestation until parturition. The prepartum diet had a dietary cation-anion difference of -128 mEq/kg of dry matter. All cows were fed a common postpartum diet containing 46 µg of vitamin D3/kg of dry matter without further supplementation of treatments. Concentrations of vitamin D metabolites, Ca, Mg, and P in serum were measured pre- and postpartum, in addition to total-tract digestibility and urinary excretion of Ca, Mg, and P in the prepartum period. Feeding 3 mg compared with 1 mg of CAL increased serum 25-hydroxyvitamin D3 (CAL1 = 94 vs. CAL3 = 173 ± 3 ng/mL). In comparison, the increment in serum 25-hydroxyvitamin D3 from feeding 3 mg compared with 1 mg of CHOL was small (CHOL1 = 58 vs. CHOL3 = 64 ± 3 ng/mL). Feeding CAL increased prepartum concentration of P in serum compared with CHOL (CHOL = 1.87 vs. CAL = 2.01 ± 0.02 mM), regardless of the amount fed, but neither source nor amount affected prepartum Ca or Mg in serum. Feeding CAL increased serum Ca and P for the first 11 d postpartum compared with CHOL (CHOL = 2.12 vs. CAL = 2.16 ± 0.01 mM serum Ca; CHOL = 1.70 vs. CAL = 1.78 ± 0.02 mM serum P) but the amount of vitamin D did not affect postpartum concentrations of Ca, Mg, and P in serum. Feeding CAL increased prepartum apparent digestibility of Ca compared with CHOL (CHOL = 26.6 vs. CAL = 33.5 ± 2.8%) but treatments did not affect Ca retention prepartum. Neither source nor amount of vitamin D affected Mg and P apparent digestibility, but CAL decreased the concentration of P excreted in urine during the prepartum period (CHOL = 1.8 vs. CAL = 0.8 ± 0.3 g/d). Calcidiol tended to increase the amount of Ca secreted in colostrum (CHOL = 9.1 vs. CAL = 11.2 ± 0.9 g/d) and Ca excreted in urine postpartum (CHOL = 0.4 vs. CAL = 0.6 ± 0.1 g/d) compared with CHOL. Collectively, feeding CAL at 1 or 3 mg/d compared with CHOL in the last 24 d of gestation is an effective way to increase periparturient serum P concentration and postpartum serum Ca of dairy cows fed a prepartum diet with negative DCAD.

Vitamin D3 supplementation ameliorates cognitive impairment and alters neurodegenerative and inflammatory markers in scopolamine induced rat model.

A multifaceted approach can be effective for the treatment of dementia including the most common form, Alzheimer's disease (AD). However, currently, it involves only symptomatic treatment with cholinergic drugs. Beneficial effects of high Vitamin D3 levels or its intake in the prevention and treatment of cognitive disorders have been reported. Thus, the present study examined the preventive effect of Vitamin D3 (Calcitriol) supplementation on cognitive impairment and evaluated its impact on the accumulation or degradation of Aß plaques. A single intraperitoneal injection of scopolamine was used to induce cognitive impairment in rats. Treatment of Vitamin D3 was provided for 21 days after the injection. Various behavioral parameters like learning, spatial memory and exploratory behavior, biochemical alterations in the brain homogenate and histology of the hippocampus were investigated. Our results indicated that scopolamine-induced rats depicted cognitive deficits with high Aß levels and hyperphosphorylated tau proteins in the brain tissue, while Vitamin D supplementation could significantly improve the cognitive status and lower these protein levels. These results were supported by the histopathological and immunohistochemical staining of the hippocampal brain region. Furthermore, mechanistic analysis depicted that Vitamin D supplementation improved the Aß protein clearance by increasing the neprilysin levels. It also reduced the accumulation of Aß plaques by lowering neuroinflammation as well as oxidative stress. The present findings indicate that Vitamin D3 supplementation can ameliorate cognitive deficits and thereby delay AD progression by increasing Aß plaque degradation, reducing inflammation and oxidative stress.

Vitamin D Promotes Remyelination by Suppressing c-Myc and Inducing Oligodendrocyte Precursor Cell Differentiation after Traumatic Spinal Cord Injury.

Demyelination due to oligodendrocytes loss occurs after traumatic spinal cord injury (TSCI). Several studies have suggested the therapeutic potential of vitamin D (VitD) in demyelinating diseases. However, experimental evidence in the context of TSCI is limited, particularly in the presence of prior VitD-deficiency. In the present study, a contusion and a transection TSCI rat model were used, representing mild and severe injury, respectively. Motor recovery was assessed in rats with normal VitD level or with VitD-deficiency after 8 weeks' treatment post-TSCI (Cholecalciferol, 500 IU/kg/day). The impact on myelin integrity was examined by transmission electron microscopy and studied in vitro using primary culture of oligodendrocytes. We found that VitD treatment post-TSCI effectively improved hindlimb movement in rats with normal VitD level irrespective of injury severity. However, cord-transected rats with prior deficiency did not seem to benefit from VitD supplementation. Our data further suggested that having sufficient VitD was essential for persevering myelin integrity after injury. VitD rescued oligodendrocytes from apoptotic cell death in vitro and enhanced their myelinating ability towards dorsal root axons. Enhanced myelination was mediated by increased oligodendrocyte precursor cells (OPCs) differentiation into oligodendrocytes in concert with c-Myc downregulation and suppressed OPCs proliferation. Our study provides novel insights into the functioning of VitD as a regulator of OPCs differentiation as well as strong preclinical evidence supporting future clinical testing of VitD for TSCI.

VITAMIN D AND OPHTHALMOPATHIAS. A REVIEW.

The importance of vitamin D3 (hydroxycholecalciferol) as one of the liposoluble vitamins is known in the prevention and treatment of metabolic bone diseases (rickets, osteomalacia, osteoporosis). In recent years, however, information has increased on the importance of vitamin D3 in numerous organ systems and in the pathogenesis of various diseases, e. g. ophthalmopathies. The immunological functions of vitamin D3 are the subject of studies dealing with autoimmune optic nerve disorders and their results appear to have a positive effect on demyelinating diseases. It also plays an important role in maintaining the thickness of the retinal nerve fiber layer, but its additional administration has not been successful. Optical neuritis may be the first sign of multiple sclerosis. It appears that sufficient serum vitamin D3 levels may protect patients from deterioration in the form of a further attack of demyelination. The course of diabetic retinopathy is probably also influenced by vitamin D3, inter alia, by correlating the fact that its receptor and the enzymes of its metabolism are expressed on the retina. Low serum levels of vitamin D3 may even trigger age-related macular degeneration. Conversely, higher dietary intake of vitamin D3 may positively affect neovascularization. The optimal level of hydroxycholecalciferol is between 60 and 200 nmol /l, the severe deficit represents a decrease below 25 nmol/l. The body can normally produce up to 10,000 IU of this vitamin after exposure to sunlight. However, the demonstration of its protective character in connection with the mentioned diseases of the retina and optic nerve will require a sufficient number of studies to confirm the facts found so far about this rediscovered vitamin.

Cholecalciferol (vitamin D3) must not be considered as an endocrine disruptor / Le cholécalciférol (la vitamine D3) ne doit pas être inclus dans la liste des perturbateurs endocriniens

A French ministerial decree planning to include cholecalciferol, i.e. vitamin D3 (VD3), in the endocrine disruptors (ED) list has generated a lot of concerns in French physicians and scientists. The aim of the present article was to discuss the scientific rationale that may support or not this decision, which seems to be due to the use of VD3 overdose as a rodenticide in some European countries. First, it is noticeable that cholecalciferol is not an "exogenous substance", a term used in all the definitions of ED, as it is largely synthesized in the skin after UVB rays exposure. Second, we did not find any published article that may support the inclusion of VD3 in the ED list. The request "vitamin D AND endocrine disruptor" reported 33 references in the PubMed database on March, 10, 2022, most of them discussing disturbances of vitamin D metabolism by EDs. Third, a large amount of studies conclude that VD3 has or may have beneficial effects on many functions that are known to be altered by EDs. In addition, we warn that learning that VD3 could be legally considered as a PE may cause the general public to mistrust vitamin D supplementation, which is not desirable in terms of public health as it may increase the already too high prevalence of vitamin D deficient individuals. We consider the aberrant decision of including cholecalciferol in the ED list should be rapidly invalidated before being effective in France and possibly disseminated in the European Union.

Un projet d'arrêté ministériel inscrivant le cholécalciférol, c'est-à-dire la vitamine D3 (VD3), dans la liste des perturbateurs endocriniens (PE) est à l'origine de débats en France. L'objectif de notre article était de préciser les arguments scientifiques pour et contre l'inscription de la VD3 dans la liste des PE, qui semble être initialement due à son utilisation à très forte dose comme raticide/rodenticide dans certains pays. Premièrement, le cholécalciférol ne peut être défini comme une substance exogène, terme utilisé dans les différentes définitions des PE, car il est largement synthétisé dans la peau suite à l'exposition aux UVB. Deuxièmement, il n'existe aucune publication dans la base de données PubMed en faveur d'une inscription de la VD3 dans la liste des PE. La requête « vitamin D AND endocrine disruptor ¼ retrouvait 33 références au 10 mars 2022, la plupart évoquant des perturbations du métabolisme de la vitamine D par les PE. Troisièmement, un grand nombre d'études concluent, au contraire, que la VD3 a des effets bénéfiques sur de nombreuses fonctions altérées par les PE. Plus largement, nous alertons sur le fait qu'apprendre que la VD3 pourrait être règlementairement considérée comme un PE pourrait occasionner, auprès du grand public, une défiance vis-à-vis de la supplémentation en vitamine D, ce qui n'est pas souhaitable en termes de santé publique car de nature à aggraver la prévalence déjà trop élevée des individus carencés en vitamine D. Il est encore temps d'éviter cette décision aberrante et non fondée.

Vitamin D3 Priming of Dendritic Cells Shifts Human Neutrophil-Dependent Th17 Cell Development to Regulatory T Cells.

Vitamin D3 (VD3) is a potential adjuvant for use in tolerogenic vaccine formulations that target dendritic cells (DCs) for the treatment of chronic inflammatory disorders, e.g., autoimmune diseases. These disorders are often associated with enhanced activity of IL-17-producing T helper 17 (Th17) cells which develop in a DC-driven and neutrophil-dependent fashion. Here, we investigated the effect of VD3 on Candida albicans-specific human T-cell differentiation, since C. albicans is a model pathogen for Th17 cell development. VD3 priming of DCs restricted neutrophil-dependent Th17 cell development and neutrophil-independent Th1 cell formation from naive CD4+ T cells. In line with this, the production of Th1/Th17-polarizing cytokines IL-12 and IL-23 by DCs was reduced by VD3 priming. Development of both FoxP3+CD127lowCD25+ Tregs and IL-10-producing T cells was significantly enhanced in VD3-primed conditions, even in the presence of neutrophils. ICOS+ Tregs, major IL-10 producers, CD69+FoxP3+, and TIGIT+FoxP3+ Tregs were significantly induced by VD3 priming as well. Our data support the potential use of VD3 as an adjuvant to induce tolerance in the treatment of autoimmune disorders, including those in which neutrophils are involved in pathogenesis, since we show that Treg development is enhanced by VD3 even in the presence of neutrophils, while Th17 cell development is restricted.

Physiologically Based Pharmacokinetic Modeling of Vitamin D3 and Metabolites in Vitamin D-Insufficient Patients.

A physiologically based pharmacokinetic (PBPK) model of vitamin D3 and metabolites [25(OH)D3, 1,25(OH)2D3, and 24,25(OH)2D3] is presented. In this study, patients with 25(OH)D3 plasma concentrations below 30 ng/ml were studied after a single dose of 5000 I.U. (125 µg) cholecalciferol, provided with 5000 I.U. daily cholecalciferol supplementation until vitamin D replete [25(OH)D3 plasma concentrations above 30 ng/ml], and had serial plasma samples were collected at each phase for 14 days. Total concentrations of vitamin D3 and metabolites were measured by ultra-high performance liquid chromatography tandem mass spectrometry. A nine-compartment PBPK model was built using MATLAB to represent the triphasic study nature (insufficient, replenishing, and sufficient). The stimulatory and inhibitory effect of 1,25(OH)2D3 were incorporated by fold-changes in the primary metabolic enzymes CYP27B1 and CYP24A1, respectively. Incorporation of dynamic adipose partition coefficients for vitamin D3 and 25(OH)D3 and variable enzymatic reactions aided in model fitting. Measures of model predictions agreed well with data from metabolites, with 97%, 88%, and 98% of the data for 25(OH)D3, 24,25(OH)2D3, and 1,25(OH)2D3, respectively, within twofold of unity (fold error values between 0.5 and 2.0). Bootstrapping was performed and optimized parameters were reported with 95% confidence intervals. This PBPK model could be a useful tool for understanding the connections between vitamin D and its metabolites under a variety of clinical situations. SIGNIFICANCE STATEMENT: This study developed a physiologically based pharmacokinetic (PBPK) model of vitamin D3 and metabolites for patients moving from an insufficient to a repleted state over a period of 16 weeks.

Vitamin D3 decreases TNF-α-induced inflammation in lung epithelial cells through a reduction in mitochondrial fission and mitophagy.

Previous work has shown an association between vitamin D3 deficiency and an increased risk for acquiring various inflammatory diseases. Vitamin D3 can reduce morbidity and mortality in these patients via different mechanisms. Lung inflammation is an important event in the initiation and development of respiratory disorders. However, the anti-inflammatory effects of vitamin D3 and the underlying mechanisms remained to be determined. The purpose of this study was to examine the effects and mechanisms of action of vitamin D3 (Vit. D) on the expression of intercellular adhesion molecule-1 (ICAM-1) in vitro and in vivo with or without tumor necrosis factor α (TNF-α) treatment. Pretreatment with Vit. D reduced the expression of ICAM-1 and leukocyte adhesion in TNF-α-treated A549 cells. TNF-α increased the accumulation of mitochondrial reactive oxygen species (mtROS), while Vit. D reduced this effect. Pretreatment with Vit. D attenuated TNF-α-induced mitochondrial fission, as shown by the increased expression of mitochondrial fission factor (Mff), phosphorylated dynamin-related protein 1 (p-DRP1), and mitophagy-related proteins (BCL2/adenovirus E1B 19 kDa protein-interacting protein 3, Bnip3) in A549 cells. Inhibition of DRP1 or Mff significantly decreased ICAM-1 expression. In addition, we found that Vit. D decreased TNF-α-induced ICAM-1 expression, mitochondrial fission, and mitophagy via the AKT and NF-κB pathways. Moreover, ICAM-1 expression, mitochondrial fission, and mitophagy were increased in the lung tissues of TNF-α-treated mice, while Vit. D supplementation reduced these effects. In this study, we elucidated the mechanisms by which Vit. D reduces the expression of adhesion molecules in models of airway inflammation. Vit. D might be served as a novel therapeutic agent for the targeting of epithelial activation in lung inflammation. Graphical Headlights: • The expression of DRP1 and Mff, mitochondrial fission-related proteins, was increased in TNF-α-treated A549 cells. • The expression of Bnip3 and LC3B, mitophagy-related proteins, was increased in TNF-α-treated A549 cells. • Vit. D pretreatment decreased TNF-α-induced inflammation through the reduction of mitochondrial fission and mitophagy in A549 cells.

Assessment of a Novel Vitamin D3 Formulation with Nanostructured Lipid Carriers for Transdermal Delivery.

OBJECTIVE: Develop and assess a transdermal emulsion loaded with nanostructured lipid carriers for vitamin D3 supplementation. METHODS: Vitamin D3 loaded nanostructured lipid carriers, produced via high shear homogenization and ultrasonication, were assessed for their particle size, distribution, morphology, zeta potential, entrapment efficiency, and cytotoxicity. They were incorporated into a transdermal vehicle, and the stability and ex vivo permeation were evaluated. RESULTS: Spherical nanoparticles were developed with a particle size of 192.5 nm, a polydispersity index of 0.13, a zeta potential of -29.0 mV, and an entrapment efficiency of 99.75%. They were stable (particle size and distribution) for 15 days when stored in a refrigerator, and for 30 days at room temperature and 32°C. The nanoparticles decreased the drug cytotoxicity against fibroblasts, as shown by IC50 (nanoparticle: 32.48 µg mL-1 vitamin D3: 16.73 µg mL-1). The emulsion loaded with nanoparticles minimized the degradation of vitamin D3 when compared with the nanoparticle dispersion. Additionally, the emulsion provided the skin permeation of vitamin D3 following the recommended daily allowance. CONCLUSION: To the best of our knowledge, this is the first study to use nanostructured lipid carriers for transdermal delivery of vitamin D. The developed formulation is a promising strategy to overcome the vitamin D3 variable oral bioavailability. It also represents a comfortable route of administration; thus it could be beneficial for patients and clinicians. However, further studies are needed to allow the permeation of larger amounts of vitamin D3, and the combination of these nanoparticles with microneedles would be interesting.

Vitamin D3 Attenuates Viral-Induced Inflammation and Fibrotic Responses in Bronchial Smooth Muscle Cells.

Toll-like receptor 3 (TLR3) activation by viral infections plays a key role in promoting inflammatory immune responses that contribute to pulmonary fibrosis in chronic inflammatory respiratory diseases. Vitamin D3 has been shown to be beneficial to patients with asthma and chronic obstructive pulmonary disease (COPD) through its anti-inflammatory and anti-fibrotic properties. Smooth muscle cells are one of the major contributors to airway remodeling in asthma and COPD. We therefore aimed to investigate the effect of vitamin D3 treatment on viral-induced TLR3 responses in Bronchial Smooth Muscle Cells (BSMCs) as a mechanism contributing to pulmonary fibrosis in asthma and COPD. Primary BSMCs from patients with asthma (n=4), COPD (n=4), and healthy control subjects (n=6) were treated with polyinosinic: polycytidylic acid (polyI:C), TLR3 agonist in the presence or absence of vitamin D3 (1,25D3). Here we report the mRNA expression and protein levels of pro-inflammatory and pro-fibrotic markers (IL-6, IFN-ß1, CCL2/MCP-1, fibronectin 1 and type I collagen) among BSMCs groups: asthma, COPD, and healthy controls. We show that at the baseline, prior to polyI:C stimulation, asthma and COPD BSMCs presented increased pro-inflammatory and pro-fibrotic state compared to healthy control subjects, as measured by quantitative PCR and immunoassays (ELISA/Flow Cytometry. Ligation of TLR3 by polyI:C in BSMCs was associated with increased TLR3 mRNA expression, and 1,25D3 treatment significantly reduced its expression. In addition, 1,25D3 decreased the expression of IL-6, IFN-ß1, CCL2, FN1 and COL1A1 induced by polyI:C in BSMCs. The regulatory effect of 1,25D3 treatment on polyI:C-stimulated BSMCs was further confirmed at protein levels. Our findings suggest that vitamin D3 attenuates TLR3 agonist-induced inflammatory and fibrotic responses in BSMCs and support the clinical relevance of vitamin D3 supplementation in patients with viral infections having chronic respiratory diseases, such as asthma and COPD.