Vitamin D Receptor Is Necessary for Mitochondrial Function and Cell Health

Vitamin-D as a multifunctional molecule for overall well-being: An integrative review

Vitamin D is amongst the most important biomolecules to regularize and help in sustainable health, however, based on the studies, deficiency of this multifunctional vitamin is common. Vitamin D, besides playing a role in the form of vitamins, also acts as a multifunctional hormone (steroid). Vitamin D is synthesized inside the body through various steps starting from ultraviolet radiation exposure and comes from limited food sources, however, vitamin D-fortified food products are still among the major sources of vitamin D. Current review, focused on how vitamin D acts as a multifunctional molecule by effecting different functions in the body in normal or specific conditions and how it is important in fortification and how it can be managed from the available literature till date. During the Covid pandemic, people were aware of vitamin D and took supplementation, fortified foods, and sat under sunlight. As COVID prevalence decreases, people start forgetting about vitamin D. Vitamin D is very crucial for overall well-being as it has protective effects against a broad range of diseases as it can reduce inflammation, cancer cell growth and helps in controlling infection, increase metabolism, muscle, and bone strength, neurotransmitter expression, etc. Therefore, the present review is to provoke the population, and fulfillment of the vitamin D recommended dietary allowance daily must be confirmed.

The exposure to extremely low frequency electromagnetic-fields inhibits the growth and potentiates the sensitivity to chemotherapy of bidimensional and tridimensional human osteosarcoma models

We previously established a thermodynamical model to calculate the specific frequencies of extremely low frequency-electromagnetic field (ELF-EMF) able to arrest the growth of cancer cells. In the present study, for the first time, we investigated the efficacy of this technology on osteosarcoma, and we applied a precise frequency of the electromagnetic field on three human osteosarcoma cell lines, grown as adherent cells and spheroids. We evaluated the antitumour efficacy of irradiation in terms of response to chemotherapeutic treatments, which is usually poor in this type of cancer. Importantly, the results of this novel combinatorial approach revealed that the specific exposure can potentiate the efficacy of several chemotherapeutic drugs, both on bidimensional and tridimensional cancer models. The effectiveness of cisplatinum, methotrexate, ifosfamide and doxorubicin was greatly increased by the concomitant application of the specific ELF-EMF. Moreover, our experiments confirmed that ELF-EMF inhibited the proliferation and modulated the mitochondrial metabolism of all cancer models tested, whereas mesenchymal cells were not affected. The latter finding is extremely valuable, given the importance of preserving the cell reservoir necessary for tissue regeneration after chemotherapy. Altogether, this novel evidence opens new avenues to the clinical applications of ELF-EMF in oncology.

Pro-inflammatory cytokine IL-21 correlates with the reactive oxygen species and 25-hydroxy vitamin D in rheumatoid arthritis patients

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune disorder and its characteristics include the immune system's invasion of the healthy lining of the joints and the articular structures degeneration. The IL-21 pro-inflammatory cytokine, and the reactive oxygen species (ROS) might have a role in the RA etiopathogenesis. The present study assessed the correlation of IL-21 with vitamin 25(OH)D and the ROS.

METHODS

The study included 120 RA patients and 60 healthy group. The RA patients were categorized based on rheumatoid factor (RF) seropositivity or seronegativity and the RA severity. Chemiluminescent immunoassay and 10% hematocrit were used to check levels of vitamin 25(OH)D and ROS, respectively. ELISA was used for the detection of IL-21 in the plasma.

RESULTS

The RA patients had a significantly reduced vitamin 25(OH)D level compared to the healthy controls. The IL-21 and ROS were however significantly increased in the RA patients compared to the controls. Further, the seropositive RF and the high RA severity patients had significant IL-21 and ROS increase in comparison with the seronegative RF and the low severity RA patients. Finally, IL-21 negatively correlated with vitamin 25(OH)D, but positively correlated with the ROS.

CONCLUSION

This is the first investigation to confirm the relationship between IL-21 with vitamin 25(OH)D and the ROS among the RA patients. The findings indicate that vitamin 25(OH)D is reduced in the RA patients' serum. ROS and IL-21 are also associated with increased RA severity.

Malignant Melanoma: An Overview, New Perspectives, and Vitamin D Signaling

Melanoma, originating through malignant transformation of melanin-producing melanocytes, is a formidable malignancy, characterized by local invasiveness, recurrence, early metastasis, resistance to therapy, and a high mortality rate. This review discusses etiologic and risk factors for melanoma, diagnostic and prognostic tools, including recent advances in molecular biology, omics, and bioinformatics, and provides an overview of its therapy. Since the incidence of melanoma is rising and mortality remains unacceptably high, we discuss its inherent properties, including melanogenesis, that make this disease resilient to treatment and propose to use AI to solve the above complex and multidimensional problems. We provide an overview on vitamin D and its anticancerogenic properties, and report recent advances in this field that can provide solutions for the prevention and/or therapy of melanoma. Experimental papers and clinicopathological studies on the role of vitamin D status and signaling pathways initiated by its active metabolites in melanoma prognosis and therapy are reviewed. We conclude that vitamin D signaling, defined by specific nuclear receptors and selective activation by specific vitamin D hydroxyderivatives, can provide a benefit for new or existing therapeutic approaches. We propose to target vitamin D signaling with the use of computational biology and AI tools to provide a solution to the melanoma problem.

Vitamin D and Sulforaphane Decrease Inflammatory Oxidative Stress and Restore the Markers of Epithelial Integrity in an In Vitro Model of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is strictly linked to chronic oxidative stress, inflammation, loss of epithelial barrier integrity, and often with abnormal new blood vessel development. In this study, the retinal epithelial cell line ARPE-19 was treated with pro-inflammatory transforming growth factor-beta (TGF-β) to investigate the activity of vitamin D (VD) and sulforaphane (SF) in abating the consequences of oxidative stress and inflammation. The administration of VD and SF lowered reactive oxygen species (ROS) levels, and abated the related expression of the pro-inflammatory cytokines interleukin-6 and interleukin-8 induced by TGF-β. We evaluated mitochondrial respiration as a source of ROS production, and we discovered that the increased transcription of respiratory elements triggered by TGF-β was prevented by VD and SF. In this model of inflamed epithelium, the treatment with VD and SF also reduced the secretion of VEGF, a key angiogenic factor, and restored the markers of epithelial integrity. Remarkably, all the observed biological effects were potentiated by the co-stimulation with the two compounds and were not mediated by VD receptor expression but rather by the ERK 1/2 pathway. Altogether, the results of this study reveal the powerful synergistic anti-inflammatory activity of SF and VD and lay the foundation for future clinical assessment of their efficacy in AMD.

Mini-encyclopedia of mitochondria-relevant nutraceuticals protecting health in primary and secondary care-clinically relevant 3PM innovation

Despite their subordination in humans, to a great extent, mitochondria maintain their independent status but tightly cooperate with the "host" on protecting the joint life quality and minimizing health risks. Under oxidative stress conditions, healthy mitochondria promptly increase mitophagy level to remove damaged "fellows" rejuvenating the mitochondrial population and sending fragments of mtDNA as SOS signals to all systems in the human body. As long as metabolic pathways are under systemic control and well-concerted together, adaptive mechanisms become triggered increasing systemic protection, activating antioxidant defense and repair machinery. Contextually, all attributes of mitochondrial patho-/physiology are instrumental for predictive medical approach and cost-effective treatments tailored to individualized patient profiles in primary (to protect vulnerable individuals again the health-to-disease transition) and secondary (to protect affected individuals again disease progression) care. Nutraceuticals are naturally occurring bioactive compounds demonstrating health-promoting, illness-preventing, and other health-related benefits. Keeping in mind health-promoting properties of nutraceuticals along with their great therapeutic potential and safety profile, there is a permanently growing demand on the application of mitochondria-relevant nutraceuticals. Application of nutraceuticals is beneficial only if meeting needs at individual level. Therefore, health risk assessment and creation of individualized patient profiles are of pivotal importance followed by adapted nutraceutical sets meeting individual needs. Based on the scientific evidence available for mitochondria-relevant nutraceuticals, this article presents examples of frequent medical conditions, which require protective measures targeted on mitochondria as a holistic approach following advanced concepts of predictive, preventive, and personalized medicine (PPPM/3PM) in primary and secondary care.

Insight into vitamin D3 action within the ovary-Basic and clinical aspects

Vitamin D3 is a fat-soluble secosteroid predominantly synthesized in the skin or delivered with a diet. Nevertheless, recently it is considered more as a hormone than a vitamin due to its pleiotropic function within the organism ensured by widely distributed vitamin D receptors and metabolic enzymes. Besides the main role in calcium and phosphorus homeostasis, vitamin D3 was shown to regulate many cellular and metabolic processes in normal and cancerous tissues within the immune system, the cardiovascular system, the respiratory system and the endocrine system. The ovary is an important extraskeletal tissue of vitamin D3 action and local metabolism, indicating its role in the regulation of ovarian functions upon physiological and pathological conditions. This chapter reviews firstly the updated information about vitamin D3 metabolism and triggered intracellular pathways. Furthermore, the basic information about ovarian physiology and several aspects of vitamin D3 effects within the ovary are presented. Finally, the special attention is paid into possible mechanism of vitamin D3 action within ovarian pathologies such as premature ovarian failure, polycystic ovary syndrome, and ovarian cancer, considering its clinical application as alternative therapy.

The immune cell transcriptome is modulated by vitamin D3 supplementation in people with a first demyelinating event participating in a randomized placebo-controlled trial

Vitamin D deficiency is a risk factor for developing multiple sclerosis. The PrevANZ trial was conducted to determine if vitamin D3 supplementation can prevent recurrent disease activity in people with a first demyelinating event. As a sub-study of this trial, we investigated the effect of supplementation on peripheral immune cell gene expression. Participants were randomized to 1000, 5000 or 10,000 international units daily of vitamin D3 or placebo. Peripheral blood was collected at baseline and 12 weeks and sent for ribonucleic acid sequencing. Datasets from 55 participants were included. Gene expression was modulated by high dose supplementation. Antigen presentation and viral response pathways were upregulated. Oxidative phosphorylation and immune signaling pathways, including tumor necrosis factor-alpha and interleukin-17 signaling, were downregulated. Overall, vitamin D3 supplementation for 12 weeks modulated the peripheral immune cell transcriptome with induction of anti-inflammatory gene expression profiles. Our results support a dose-dependent effect of vitamin D3 supplementation on immune gene expression.

VDR regulates mitochondrial function as a protective mechanism against renal tubular cell injury in diabetic rats

PURPOSE

To investigate the regulatory effect and mechanism of Vitamin D receptor (VDR) on mitochondrial function in renal tubular epithelial cell under diabetic status.

METHODS

The diabetic rats induced by streptozotocin (STZ) and HK-2 cells under high glocose(HG)/transforming growth factor beta (TGF-β) stimulation were used in this study. Calcitriol was administered for 24 weeks. Renal tubulointerstitial injury and some parameters of mitochondrial function including mitophagy, mitochondrial fission, mitochondrial ROS, mitochondrial membrane potential (MMP), mitochondrial ATP, Complex V activity and mitochondria-associated ER membranes (MAMs) integrity were examined. Additionally, paricalcitol, 3-MA (an autophagy inhibitor), VDR over-expression plasmid, VDR siRNA and Mfn2 siRNA were applied in vitro.

RESULTS

The expression of VDR, Pink1, Parkin, Fundc1, LC3II, Atg5, Mfn2, Mfn1 in renal tubular cell of diabetic rats were decreased significantly. Calcitriol treatment reduced the levels of urinary albumin, serum creatinine and attenuated renal tubulointerstitial fibrosis in STZ induced diabetic rats. In addition, VDR agonist relieved mitophagy dysfunction, MAMs integrity, and inhibited mitochondrial fission, mitochondrial ROS. Co-immunoprecipitation analysis demonstrated that VDR interacted directly with Mfn2. Mitochondrial function including mitophagy, mitochondrial membrane potential (MMP), mitochondrial Ca2+, mitochondrial ATP and Complex V activity were decreased dramatically in HK-2 cells under HG/TGF-β ambience. In vitro pretreatment of HK-2 cells with autophagy inhibitor 3-MA, VDR siRNA or Mfn2 siRNA negated the activating effects of paricalcitol on mitochondrial function. Pricalcitol and VDR over-expression plasmid activated Mfn2 and then partially restored the MAMs integrity. Additionally, VDR restored mitophagy was partially associated with MAMs integrity through Fundc1.

CONCLUSION

Activated VDR could contribute to restore mitophagy through Mfn2-MAMs-Fundc1 pathway in renal tubular cell. VDR could recover mitochondrial ATP, complex V activity and MAMs integrity, inhibit mitochondrial fission and mitochondrial ROS. It indicating that VDR agonists ameliorate renal tubulointerstitial fibrosis in diabetic rats partially via regulation of mitochondrial function.

Safety and efficacy of antioxidant therapy in children and adolescents with attention deficit hyperactivity disorder: A systematic review and network meta-analysis

OBJECTIVE

To systematically evaluate the safety and efficacy of antioxidant therapy in children and adolescents with attention deficit hyperactivity disorder (ADHD).

METHODS

Randomized controlled trials and prospective studies on antioxidant therapy in children and adolescents with ADHD were searched in PubMed, Embase, and Cochrane Library from the inception of databases to November 12, 2022. Two investigators independently screened the literature, extracted data, and evaluated the quality of the included studies. Network meta-analysis (PROSPERO registration number CRD 42023382824) was carried out by using R Studio 4.2.1.

RESULTS

48 studies involving 12 antioxidant drugs (resveratrol, pycnogenol, omega-3, omega-6, quercetin, phosphatidylserine, almond, vitamin D, zinc, folic acid, ginkgo biloba, Acetyl-L-carnitine) were finally included, with 3,650 patients. Network meta-analysis showed that omega-6 (0.18), vitamin D (0.19), and quercetin (0.24) were the top three safest drugs according to SUCRA. The omega-3 (SUCRA 0.35), pycnogenol (SUCRA 0.36), and vitamin D (SUCRA 0.27) were the most effective in improving attention, hyperactivity, and total score of Conners' parent rating scale (CPRS), respectively. In terms of improving attention, hyperactivity, and total score of Conners' teacher rating scale (CTRS), pycnogenol (SUCRA 0.32), phosphatidylserine+omega-3 (SUCRA 0.26), and zinc (SUCRA 0.34) were the most effective, respectively. In terms of improving attention, hyperactivity and total score of ADHD Rating Scale-Parent, the optimal agents were phosphatidylserine (SUCRA 0.39), resveratrol+MPH (SUCRA 0.24), and phosphatidylserine (SUCRA 0.34), respectively. In terms of improving attention, hyperactivity and total score of ADHD Rating Scale-Teacher, pycnogenol (SUCRA 0.32), vitamin D (SUCRA 0.31) and vitamin D (SUCRA 0.18) were the optimal agents, respectively. The response rate of omega-3+6 was the highest in CGI (SUCRA 0.95) and CPT (SUCRA 0.42).

CONCLUSION

The rankings of safety and efficacy of the 12 antioxidants vary. Due to the low methodological quality of the included studies, the probability ranking cannot fully explain the clinical efficacy, and the results need to be interpreted with caution. More high-quality studies are still needed to verify our findings.

Mitochondrial Dysfunction: A Key Player in Brain Aging and Diseases

Mitochondria are thought to have become incorporated within the eukaryotic cell approximately 2 billion years ago and play a role in a variety of cellular processes, such as energy production, calcium buffering and homeostasis, steroid synthesis, cell growth, and apoptosis, as well as inflammation and ROS production. Considering that mitochondria are involved in a multitude of cellular processes, mitochondrial dysfunction has been shown to play a role within several age-related diseases, including cancers, diabetes (type 2), and neurodegenerative diseases, although the underlying mechanisms are not entirely understood. The significant increase in lifespan and increased incidence of age-related diseases over recent decades has confirmed the necessity to understand the mechanisms by which mitochondrial dysfunction impacts the process of aging and age-related diseases. In this review, we will offer a brief overview of mitochondria, along with structure and function of this important organelle. We will then discuss the cause and consequence of mitochondrial dysfunction in the aging process, with a particular focus on its role in inflammation, cognitive decline, and neurodegenerative diseases, such as Huntington's disease, Parkinson's disease, and Alzheimer's disease. We will offer insight into therapies and interventions currently used to preserve or restore mitochondrial functioning during aging and neurodegeneration.

Tremendous Fidelity of Vitamin D3 in Age-related Neurological Disorders

Vitamin D3 (VD) is a secosteroid hormone and shows a pleiotropic effect in brain-related disorders where it regulates redox imbalance, inflammation, apoptosis, energy production, and growth factor synthesis. Vitamin D3's active metabolic form, 1,25-dihydroxy Vitamin D3 (1,25(OH)2D3 or calcitriol), is a known regulator of several genes involved in neuroplasticity, neuroprotection, neurotropism, and neuroinflammation. Multiple studies suggest that VD deficiency can be proposed as a risk factor for the development of several age-related neurological disorders. The evidence for low serum levels of 25-hydroxy Vitamin D3 (25(OH)D3 or calcidiol), the major circulating form of VD, is associated with an increased risk of Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), dementia, and cognitive impairment. Despite decades of evidence on low VD association with neurological disorders, the precise molecular mechanism behind its beneficial effect remains controversial. Here, we will be delving into the neurobiological importance of VD and discuss its benefits in different neuropsychiatric disorders. The focus will be on AD, PD, and HD as they share some common clinical, pathological, and epidemiological features. The central focus will be on the different attributes of VD in the aspect of its anti-oxidative, anti-inflammatory, anti-apoptotic, anti-cholinesterase activity, and psychotropic effect in different neurodegenerative diseases.

Vitamin D and Its Role on the Fatigue Mitigation: A Narrative Review

Vitamin D has historically been associated with bone metabolism. However, over the years, a growing body of evidence has emerged indicating its involvement in various physiological processes that may influence the onset of numerous pathologies (cardiovascular and neurodegenerative diseases, rheumatological diseases, fertility, cancer, diabetes, or a condition of fatigue). This narrative review investigates the current knowledge of the pathophysiological mechanisms underlying fatigue and the ways in which vitamin D is implicated in these processes. Scientific studies in the databases of PubMed, Scopus, and Web of Science were reviewed with a focus on factors that play a role in the genesis of fatigue, where the influence of vitamin D has been clearly demonstrated. The pathogenic factors of fatigue influenced by vitamin D are related to biochemical factors connected to oxidative stress and inflammatory cytokines. A role in the control of the neurotransmitters dopamine and serotonin has also been demonstrated: an imbalance in the relationship between these two neurotransmitters is linked to the genesis of fatigue. Furthermore, vitamin D is implicated in the control of voltage-gated calcium and chloride channels. Although it has been demonstrated that hypovitaminosis D is associated with numerous pathological conditions, current data on the outcomes of correcting hypovitaminosis D are conflicting. This suggests that, despite the significant involvement of vitamin D in regulating mechanisms governing fatigue, other factors could also play a role.

Different impact of vitamin D on mitochondrial activity and morphology in normal and malignant keratinocytes, the role of genomic pathway

Deregulation of mitochondria activity is one of the hallmarks of cancerogenesis and an important target for cancer therapy. Therefore, we compared the impact of an active form of vitamin D3 (1,25(OH)2D3) on mitochondrial morphology and bioenergetics in human squamous cell carcinoma (A431) and immortalized HaCaT keratinocytes. It was shown that mitochondria of cancerous A431 cells differ from that observed in HaCaT keratinocytes in terms of network, morphology, bioenergetics, glycolysis, and mitochondrial DNA copy number, while treatment of A431 with 1,25(OH)2D3 partially eliminates these differences. Furthermore, mitochondrial membrane potential, basal respiration, and mitochondrial reactive oxygen species production were decreased in A431 cells treated with 1,25(OH)2D3. Additionally, the expression and protein level of mitophagy marker PINK1 was significantly increased in A431 1,25(OH)2D3 treated cells, but not observed in treated HaCaT cells. Knockout of VDR (vitamin D receptor) or RXRA (binding partner retinoid X receptor) partially altered mitochondrial morphology and function as well as mitochondrial response to 1,25(OH)2D3. Transcriptomic analysis on A431 cells treated with 1,25(OH)2D3 revealed modulation of expression of several mitochondrial-related genes involved in mitochondrial depolarization, mitochondrial protein translation (i.e. LYRM9, MARS2), and fusion-fission (OPA1, FIS1, MFN1 and 2), however, none of the genes coded by mitochondrial DNA was affected. Interestingly, in silico analyses of nuclear-encoded mitochondrial genes revealed that they are rather activated by the secondary genomic response to 1,25(OH)2D3. Taken together, 1,25(OH)2D3 remodels mitochondrial architecture and bioenergetics through VDR-dependent and only partially RXRA-dependent activation of the genomic pathway, thus outlining a new perspective for anticancer properties of vitamin D3 in relation to mitochondria in squamous cell carcinoma.

Mitochondrial might: powering the peripartum for risk and resilience

The peripartum period, characterized by dynamic hormonal shifts and physiological adaptations, has been recognized as a potentially vulnerable period for the development of mood disorders such as postpartum depression (PPD). Stress is a well-established risk factor for developing PPD and is known to modulate mitochondrial function. While primarily known for their role in energy production, mitochondria also influence processes such as stress regulation, steroid hormone synthesis, glucocorticoid response, GABA metabolism, and immune modulation - all of which are crucial for healthy pregnancy and relevant to PPD pathology. While mitochondrial function has been implicated in other psychiatric illnesses, its role in peripartum stress and mental health remains largely unexplored, especially in relation to the brain. In this review, we first provide an overview of mitochondrial involvement in processes implicated in peripartum mood disorders, underscoring their potential role in mediating pathology. We then discuss clinical and preclinical studies of mitochondria in the context of peripartum stress and mental health, emphasizing the need for better understanding of this relationship. Finally, we propose mitochondria as biological mediators of resilience to peripartum mood disorders.

Blackcurrant Anthocyanins Improve Blood Lipids and Biomarkers of Inflammation and Oxidative Stress in Healthy Women in Menopause Transition without Changing Body Composition

Recent cell and animal studies suggest the potential of blackcurrants (BCs; Ribes nigrum) as a dietary agent that may reduce the risk of cardiovascular disease (CVD) by improving dyslipidemia, oxidative stress, and inflammation. This study aimed to examine the effects of BC anthocyanin (ACN) extract supplementation on biomarkers of CVD risk in healthy adult women in menopause transition. The effects of BC ACN supplementation on body composition, fasting blood lipids and biomarkers of inflammation and oxidative stress were evaluated using anthropometric measures and blood samples collected from a pilot randomized controlled clinical trial in peri- and early postmenopausal women. Thirty-eight eligible peri- and early postmenopausal women aged 45-60 completed the entire trial, in which they were randomly assigned into one of three treatment groups: placebo (control group), 392 mg/day (low BC group), or 784 mg/day (high BC group) for six months. The significance of differences in outcomes was tested using repeated-measures ANOVA. Overall, following six-month BC consumption, significantly decreased triglyceride (TG) levels were observed between treatment groups (p < 0.05) in a dose-dependent manner. Plasma interleukin-1β (IL-1β) was significantly reduced in a dose and time dependent manner (p < 0.05). Significant decreases in thiobarbituric acid reactive substances (TBARS) levels were also observed between treatment groups (p < 0.05) in a dose-dependent manner. Six-month change in oxidized LDL was inversely correlated with changes in catalase (CAT) and total antioxidant capacity (TAC) (p < 0.05), while C-reactive protein (hs-CRP) change was positively correlated with changes in TG and IL-1β (p < 0.01). Together, these findings suggest that daily BC consumption for six months effectively improved dyslipidemia, inflammation, and lipid peroxidation, thus potentially mitigating the risk of postmenopausal CVD development in study participants. Future studies with larger sample sizes and at-risk populations are warranted to confirm these findings.

Vitamin D and Periodontal Health: A Systematic Review

The role of vitamin D in maintaining gum well-being is crucial. However, scientific research reported that the connotations of cholecalciferol and periodontal health have been divested in the present literature. However, there is enormous heterogeneity in the data available. The current review aims to systematically review and appraise the available literature investigating the role of vitamin D in maintaining periodontal health. Studies included randomized controlled trials and clinical trials following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and cohort studies reporting associations between vitamin D and oral health in systemically healthy patients. Databases such as PubMed, Google Scholar, Scopus, Embase, and other sources, including hand search, were searched until May 2023 using together-equipped search sequences. Altogether, scientific articles that conform to the inclusion principles underwent a thorough eminence evaluation. All papers meeting inclusion criteria were subject to quality assessment, and the method used to assess the risk of bias was the Cochrane risk of bias tool. The search identified 1883 papers, among which 1435 were excluded after title evaluation. After abstract and title screening, 455 were excluded, and six full texts were assessed. After full-text evaluation, two articles were excluded, and only four were included. The data shows vitamin D's association with oral health maintenance. Along with its action on bone metabolism, it has extended function, which provides for its action as an anti-inflammatory agent and production of anti-microbial peptides, which help maintain oral health. Although the literature available is immense, there is enormous heterogenicity in the papers conducted to appraise the association between vitamin D and oral health. This systematic review has filtered all the data to review a few essential aspects of the role of vitamin D in maintaining oral physiology. Vitamin D has a linear relationship with periodontal health; however, the evidence is insufficient, and further studies must be done.

Implications of vitamin D for flesh quality of grass carp (Ctenopharyngodon idella): antioxidant ability, nutritional value, sensory quality, and myofiber characteristics

BACKGROUND

Muscle represents a unique and complex system with many components and comprises the major edible part of animals. Vitamin D is a critical nutrient for animals and is known to enhance calcium absorption and immune response. In recent years, dietary vitamin D supplementation in livestock has received increased attention due to biological responses including improving shear force in mammalian meat. However, the vitamin D acquisition and myofiber development processes in fish differ from those in mammals, and the effect of vitamin D on fish flesh quality is poorly understood. Here, the influence of dietary vitamin D on fillet quality, antioxidant ability, and myofiber development was examined in grass carp (Ctenopharyngodon idella).

METHODS

A total of 540 healthy grass carp, with an initial average body weight of 257.24 ± 0.63 g, were allotted in 6 experimental groups with 3 replicates each, and respectively fed corresponding diets with 15.2, 364.3, 782.5, 1,167.9, 1,573.8, and 1,980.1 IU/kg vitamin D for 70 d.

RESULTS

Supplementation with 1,167.9 IU/kg vitamin D significantly improved nutritional value and sensory quality of fillets, enhancing crude protein, free amino acid, lipid, and collagen contents; maintaining an ideal pH; and reducing lactate content, shear force, and cooking loss relative to respective values in the control (15.2 IU/kg) group. Average myofiber diameter and the frequency of myofibers > 50 μm in diameter increased under supplementation with 782.5-1,167.9 IU/kg vitamin D. Levels of oxidative damage biomarkers decreased, and the expression of antioxidant enzymes and nuclear factor erythroid 2-related factor 2 signaling molecules was upregulated in the 1,167.9 IU/kg vitamin D treatment compared to respective values in the control group. Furthermore, vitamin D supplementation activated cell differentiation by enhancing the expression of myogenic regulatory factors and myocyte enhancer factors compared to that in the control group. In addition, supplementation with 1,167.9 IU/kg vitamin D improved protein deposition associated with protein synthesis molecule (target of rapamycin) signaling and vitamin D receptor paralogs, along with inhibition of protein degradation (forkhead box protein 1) signaling.

CONCLUSIONS

Overall, the results demonstrated that vitamin D strengthened antioxidant ability and myofiber development, thereby enhancing nutritional value and sensory quality of fish flesh. These findings suggest that dietary vitamin D supplementation is conducive to the production of nutrient-rich, high quality aquaculture products.

Supplementation with Vitamin D3 Protects against Mitochondrial Dysfunction and Loss of BDNF-Mediated Akt Activity in the Hippocampus during Long-Term Dexamethasone Treatment in Rats

Dexamethasone (DEXA) is a commonly used steroid drug with immunosuppressive and analgesic properties. Unfortunately, long-term exposure to DEXA severely impairs brain function. This study aimed to investigate the effects of vitamin D3 supplementation during chronic DEXA treatment on neurogenesis, mitochondrial energy metabolism, protein levels involved in the BDNF-mediated Akt activity, and specific receptors in the hippocampus. We found reduced serum concentrations of 25-hydroxyvitamin D3 (25(OH)D3), downregulated proBDNF and pAkt, dysregulated glucocorticosteroid and mineralocorticoid receptors, impaired mitochondrial biogenesis, and dysfunctional mitochondria energy metabolism in the DEXA-treated group. In contrast, supplementation with vitamin D3 restored the 25(OH)D3 concentration to a value close to that of the control group. There was an elevation in neurotrophic factor protein level, along with augmented activity of pAkt and increased citrate synthase activity in the hippocampus after vitamin D3 administration in long-term DEXA-treated rats. Our findings demonstrate that vitamin D3 supplementation plays a protective role in the hippocampus and partially mitigates the deleterious effects of long-term DEXA administration. The association between serum 25(OH)D3 concentration and BDNF level in the hippocampus indicates the importance of applying vitamin D3 supplementation to prevent and treat pathological conditions.

The Over-Irradiation Metabolite Derivative, 24-Hydroxylumister-ol3, Reduces UV-Induced Damage in Skin

The hormonal form of vitamin D₃, 1,25(OH)₂D₃, reduces UV-induced DNA damage. UV exposure initiates pre-vitamin D₃ production in the skin, and continued UV exposure photoisomerizes pre-vitamin D₃ to produce "over-irradiation products" such as lumisterol₃ (L₃). Cytochrome P450 side-chain cleavage enzyme (CYP11A1) in skin catalyzes the conversion of L₃ to produce three main derivatives: 24-hydroxy-L₃ [24(OH)L₃], 22-hydroxy-L₃ [22(OH)L₃], and 20,22-dihydroxy-L₃ [20,22(OH)L₃]. The current study investigated the photoprotective properties of the major over-irradiation metabolite, 24(OH)L₃, in human primary keratinocytes and human skin explants. The results indicated that treatment immediately after UV with either 24(OH)L₃ or 1,25(OH)₂D₃ reduced UV-induced cyclobutane pyrimidine dimers and oxidative DNA damage, with similar concentration response curves in keratinocytes, although in skin explants, 1,25(OH)₂D₃ was more potent. The reductions in DNA damage by both compounds were, at least in part, the result of increased DNA repair through increased energy availability via increased glycolysis, as well as increased DNA damage recognition proteins in the nucleotide excision repair pathway. Reductions in UV-induced DNA photolesions by either compound occurred in the presence of lower reactive oxygen species. The results indicated that under in vitro and ex vivo conditions, 24(OH)L₃ provided photoprotection against UV damage similar to that of 1,25(OH)₂D₃.

Insights into prevention mechanisms of bioactive components from healthy diets against Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease in which senile plaques, neurofibrillary tangles, insulin resistance, oxidative stress, chronic neuroinflammation, and abnormal neurotransmission are the potential mechanisms involved in its onset and development. Although it is still an intractable disorder, diet intervention has been developed as an innovative strategy for AD prevention. Some bioactive compounds and micronutrients from food, including soy isoflavones, rutin, vitamin B1, etc., have exhibited numerous neuronal health-promoting effects in both in vivo and in vitro studies. It is well known that their antiapoptotic, antioxidative, and anti-inflammatory properties prevent the neuronal or glial cells from injury or death, minimize oxidative damage, inhibit the production of proinflammatory cytokines by modulating typical signaling pathways of MAPK, NF-kβ, and TLR, and further reduce Aβ genesis and tau hyperphosphorylation. However, parts of the dietary components trigger AD-related proteins productions and inflammasome as well as inflammatory gene upregulation. This review summarized the neuroprotective or nerve damage-promoting role and underlying molecular mechanisms of flavonoids, vitamins, and fatty acids via the data from library databases, PubMed, and journal websites, which provides a comprehensive analysis of the prevention potential of these dietary components against AD.

Role of Vitamin D in Head and Neck Cancer-Immune Function, Anti-Tumour Effect, and Its Impact on Patient Prognosis

Head and neck squamous cell carcinoma (HNSCC) describes a heterogeneous group of human neoplasms of the head and neck with high rates of morbidity and mortality, constituting about 3% of all cancers and ~1.5% of all cancer deaths. HNSCC constituted the seventh most prevalent human malignancy and the most common human cancer in the world in 2020, according to multi-population observations conducted by the GLOBOCAN group. Since approximately 60-70% of patients present with stage III/IV neoplastic disease, HNSCC is still one of the leading causes of death in cancer patients worldwide, with an overall survival rate that is too low, not exceeding 40-60% of these patients. Despite the application of newer surgical techniques and the implementation of modern combined oncological treatment, the disease often follows a fatal course due to frequent nodal metastases and local neoplastic recurrences. The role of micronutrients in the initiation, development, and progression of HNSCC has been the subject of considerable research. Of particular interest has been vitamin D, the pleiotropic biologically active fat-soluble family of secosteroids (vitamin-D-like steroids), which constitutes a key regulator of bone, calcium, and phosphate homeostasis, as well as carcinogenesis and the further development of various neoplasms. Considerable evidence suggests that vitamin D plays a key role in cellular proliferation, angiogenesis, immunity, and cellular metabolism. A number of basic science, clinical, and epidemiological studies indicate that vitamin D has multidirectional biological effects and influences anti-cancer intracellular mechanisms and cancer risk, and that vitamin D dietary supplements have various prophylactic benefits. In the 20th century, it was reported that vitamin D may play various roles in the protection and regulation of normal cellular phenotypes and in cancer prevention and adjunctive therapy in various human neoplasms, including HNSCC, by regulating a number of intracellular mechanisms, including control of tumour cell expansion and differentiation, apoptosis, intercellular interactions, angio- and lymphogenesis, immune function, and tumour invasion. These regulatory properties mainly occur indirectly via epigenetic and transcriptional changes regulating the function of transcription factors, chromatin modifiers, non-coding RNA (ncRNAs), and microRNAs (miRs) through protein-protein interactions and signalling pathways. In this way, calcitriol enhances intercellular communication in cancer biology, restores the connection with the extracellular matrix, and promotes the epithelial phenotype; it thus counteracts the tumour-associated detachment from the extracellular matrix and inhibits the formation of metastases. Furthermore, the confirmation that the vitamin D receptor (VDR) is present in many human tissues confirmed the physiopathological significance of vitamin D in various human tumours. Recent studies indicate quantitative associations between exposure to vitamin D and the incidence of HNC, i.e., cancer risk assessment included circulating calcidiol plasma/serum concentrations, vitamin D intake, the presence of the VDR gene polymorphism, and genes involved in the vitamin D metabolism pathway. Moreover, the chemopreventive efficacy of vitamin D in precancerous lesions of the head and neck and their role as predictors of mortality, survival, and recurrence of head and neck cancer are also widely discussed. As such, it may be considered a promising potential anti-cancer agent for developing innovative methods of targeted therapy. The proposed review discusses in detail the mechanisms regulating the relationship between vitamin D and HNSCC. It also provides an overview of the current literature, including key opinion-forming systematic reviews as well as epidemiological, prospective, longitudinal, cross-sectional, and interventional studies based on in vitro and animal models of HNSCC, all of which are accessible via the PubMed/Medline/EMBASE/Cochrane Library databases. This article presents the data in line with increasing clinical credibility.

COVID-19: Focusing on the Link between Inflammation, Vitamin D, MAPK Pathway and Oxidative Stress Genetics

An uncontrolled inflammatory response during SARS-CoV-2 infection has been highlighted in several studies. This seems to be due to pro-inflammatory cytokines whose production could be regulated by vitamin D, ROS production or mitogen-activated protein kinase (MAPK). Several genetic studies are present in the literature concerning genetic influences on COVID-19 characteristics, but there are few data on oxidative stress, vitamin D, MAPK and inflammation-related factors, considering gender and age. Therefore, the aim of this study was to evaluate the role of single nucleotide polymorphisms in these pathways, clarifying their impact in affecting COVID-19-related clinical features. Genetic polymorphisms were evaluated through real-time PCR. We prospectively enrolled 160 individuals: 139 patients were positive for SARS-CoV-2 detection. We detected different genetic variants able to affect the symptoms and oxygenation. Furthermore, two sub-analyses were performed considering gender and age, showing a different impact of polymorphisms according to these characteristics. This is the first study highlighting a possible contribution of genetic variants of these pathways in affecting COVID-19 clinical features. This may be relevant in order to clarify the COVID-19 etiopathogenesis and to understand the possible genetic contribution for further SARS infections.

Immunomodulatory Role of Vitamin D on Gut Microbiome in Children

Vitamin D plays a role in regulating the immune system and can be linked to the alteration of the gut microbiome, which leads to several immunological diseases. This systematic review aims to explore the relationship between Vitamin D and children's gut microbiome, as well as its impact towards the immune system. We have systematically collated relevant studies from different databases concerning changes in the gut microbiome of children from infants to 18 years old associated with Vitamin D and the immunological pathways. The studies utilized 16S rRNA sequencing analysis of fecal matter with or without Vitamin D supplementation and Vitamin D levels. Ten studies were selected for the review, among which eight studies showed significant alterations in the gut microbiome related to Vitamin D supplementation or Vitamin D levels. The taxa of the phylum Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria are the most altered in these studies. The alteration of the taxa alters the Th1 and Th2 pathways and changes the immune response. We will discuss how Vitamin D may contribute to the activation of immune pathways via its effects on intestinal barrier function, microbiome composition, and/or direct effects on immune responses. In conclusion, the studies examined in this review have provided evidence that Vitamin D levels may have an impact on the composition of children's gut microbiomes.

Gene Polymorphisms and Biological Effects of Vitamin D Receptor on Nonalcoholic Fatty Liver Disease Development and Progression

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, with increasing prevalence worldwide. The genetic and molecular background of NAFLD pathogenesis is not yet clear. The vitamin D/vitamin D receptor (VDR) axis is significantly associated with the development and progression of NAFLD. Gene polymorphisms may influence the regulation of the VDR gene, although their biological significance remains to be elucidated. VDR gene polymorphisms are associated with the presence and severity of NAFLD, as they may influence the regulation of adipose tissue activity, fibrosis, and hepatocellular carcinoma (HCC) development. Vitamin D binds to the hepatic VDR to exert its biological functions, either by activating VDR transcriptional activity to regulate gene expression associated with inflammation and fibrosis or by inducing intracellular signal transduction through VDR-mediated activation of Ca²⁺ channels. VDR activity has protective and detrimental effects on hepatic steatosis, a characteristic feature of NAFLD. Vitamin D-VDR signaling may control the progression of NAFLD by regulating immune responses, lipotoxicity, and fibrogenesis. Elucidation of the genetic and molecular background of VDR in the pathophysiology of NAFLD will provide new therapeutic targets for this disease through the development of VDR agonists, which already showed promising results in vivo.

Vitamin D receptor (BsmI) gene polymorphism and allele frequency among chronic kidney disease patients in south Indian population

The vitamin D receptor (VDR) axis plays an important role in multiple physiological renal functions. BsmI gene is one among the VDR gene plays a vital role in maintaining this VDR axis and any polymorphism in VDR gene will cause dysfunction of renal tissues. The main objective of the study is to study the link between BsmI VDR gene polymorphism and Chronic Kidney Disease (CKD). This was a case-control study, which includes 100 cases and 100 controls. BsmI gene analysis was done by polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP). Among 100 CKD study participants, BB (wild-type) genotype of BsmI gene was present in 7 patients (7%), Bb (heterozygous) genotype was present in 23 patients (23%) and bb (mutant) genotype was present in 70 patients (70%). And among 100 controls, 92 subjects were found to have BB genotype and 8 subjects were found to have Bb genotype and none of subjects were found to have bb genotypes. CKD patients with Bb and bb genotypes were found to have significantly elevated serum urea, creatinine and decreased Glomerular Filtration Rate (GFR) when compared to the BB genotype of BsmI gene. 'b' allele of BsmI gene, Bb and bb genotypes of BsmI gene plays a greater role in Guanine/Adenine single nucleotide polymorphism of BsmI gene in CKD.

Vitamin D Modulates the Response of Patient-Derived Metastatic Melanoma Cells to Anticancer Drugs

Melanoma is considered a lethal and treatment-resistant skin cancer with a high risk of recurrence, making it a major clinical challenge. Our earlier studies documented that 1,25(OH)₂D₃ and its low-calcaemic analogues potentiate the effectiveness of dacarbazine and cediranib, a pan-VEGFR inhibitor. In the current study, a set of patient-derived melanoma cultures was established and characterised as a preclinical model of human melanoma. Thus, patient-derived cells were preconditioned with 1,25(OH)₂D₃ and treated with cediranib or vemurafenib, a BRAF inhibitor, depending on the BRAF mutation status of the patients enrolled in the study. 1,25(OH)₂D₃ preconditioning exacerbated the inhibition of patient-derived melanoma cell growth and motility in comparison to monotherapy with cediranib. A significant decrease in mitochondrial respiration parameters, such as non-mitochondrial oxygen consumption, basal respiration and ATP-linked respiration, was observed. It seems that 1,25(OH)₂D₃ preconditioning enhanced cediranib efficacy via the modulation of mitochondrial bioenergetics. Additionally, 1,25(OH)₂D₃ also decreased the viability and mobility of the BRAF+ patient-derived cells treated with vemurafenib. Interestingly, regardless of the strict selection, cancer-derived fibroblasts (CAFs) became the major fraction of cultured cells over time, suggesting that melanoma growth is dependent on CAFs. In conclusion, the results of our study strongly emphasise that the active form of vitamin D, 1,25(OH)₂D₃, might be considered as an adjuvant agent in the treatment of malignant melanoma.

An Integrated Approach to Skeletal Muscle Health in Aging

A decline in muscle mass and function represents one of the most problematic changes associated with aging, and has dramatic effects on autonomy and quality of life. Several factors contribute to the inexorable process of sarcopenia, such as mitochondrial and autophagy dysfunction, and the lack of regeneration capacity of satellite cells. The physiologic decline in muscle mass and in motoneuron functionality associated with aging is exacerbated by the sedentary lifestyle that accompanies elderly people. Regular physical activity is beneficial to most people, but the elderly need well-designed and carefully administered training programs that improve muscle mass and, consequently, both functional ability and quality of life. Aging also causes alteration in the gut microbiota composition associated with sarcopenia, and some advances in research have elucidated that interventions via the gut microbiota-muscle axis have the potential to ameliorate the sarcopenic phenotype. Several mechanisms are involved in vitamin D muscle atrophy protection, as demonstrated by the decreased muscular function related to vitamin D deficiency. Malnutrition, chronic inflammation, vitamin deficiencies, and an imbalance in the muscle-gut axis are just a few of the factors that can lead to sarcopenia. Supplementing the diet with antioxidants, polyunsaturated fatty acids, vitamins, probiotics, prebiotics, proteins, kefir, and short-chain fatty acids could be potential nutritional therapies against sarcopenia. Finally, a personalized integrated strategy to counteract sarcopenia and maintain the health of skeletal muscles is suggested in this review.

Vitamin D can ameliorate premature ovarian failure by inhibiting neutrophil extracellular traps: A review

The etiology of premature ovarian failure (POF) is mainly related to inflammatory diseases, autoimmune diseases, and tumor radiotherapy and chemotherapy; however, its specific pathogenesis has not been clarified. Vitamin D (VD), a fat-soluble vitamin, is an essential steroid hormone in the human body. Neutrophil extracellular traps (NETs) are meshwork structures that are formed when neutrophils are stimulated by inflammation and other factors and are closely associated with autoimmune and inflammatory diseases. Notably, VD inhibits NET formation and intervenes in the development of POF in terms of inflammatory and immune responses, oxidative stress, and tissue fibrosis. Therefore, this study aimed to theorize the relationship between NETs, VD, and POF and provide new ideas and targets for the pathogenesis and clinical treatment of POF.

Vitamin D deficiency in rheumatoid arthritis patients of India - a single-arm meta-analysis

Background

Vitamin D deficiency is commonly seen in patients with rheumatoid arthritis (RA).

Objectives

This meta-analysis is aimed to determine the prevalence of Vitamin D deficiency in RA patients in India and also to evaluate the association between vitamin D level and disease activity.

Methods

The relevant works of literature were identified through multiple databases and data was extracted from eligible studies independently. A single-arm meta-analysis was performed to estimate the prevalence of Vitamin D deficiency in RA patients in an Indian setup and its association with disease activity. A total of 15 studies was included in the analyses.

Results

The mean serum vitamin D level was 19.99 ng/ml [95% CI 16.49-24.23]. The proportion of patients with low vitamin D level was 0.80 [95% CI 0.65- 0.90], Vitamin D deficiency was 0.56 [95% CI 0.31-0.77] and vitamin D insufficiency was 0.20 [95% CI 0.12- 0.32]. A negative relationship was seen with serum vitamin D and disease activity score.

Conclusions

The results demonstrate significant low levels of serum vitamin D levels in patients with RA and established a negative correlation of Vitamin D with RA disease activity. The current evidence suggests a rationale for Vitamin D supplementation in the management of RA.

Exploring the possible mitoprotective and neuroprotective potency of thymoquinone, betanin, and vitamin D against cytarabine-induced mitochondrial impairment and neurotoxicity in rats' brain

It has been suggested that cytarabine (Ara-C) induces toxicity via mitochondrial dysfunction and oxidative stress. Therefore, we hypothesized that mitochondrial protective agents and antioxidants can reduce cytarabine-induced neurotoxicity. For this purpose, 48 male Wistar rats were assigned into eight equal groups include control group, Ara-C (70 mg/kg, i.p.) group, Ara-C plus betanin (25 mg/kg, i.p.) group, Ara-C plus vitamin D (500 U/kg, i.p.) group, Ara-C plus thymoquinone (0.5 mg/kg, i.p.) group, betanin group, vitamin group, and thymoquinone group. The activity of acetylcholinesterase (AChE), and butyrylcholinesterase (BChE), the concentrations of antioxidants (reduced glutathione and oxidized glutathione), oxidative stress (malondialdehyde) biomarkers, mitochondrial toxicity parameters as well as histopathological alteration in brain tissues were measured. Our results demonstrated that Ara-C exposure significantly declines the brain enzymes activity (AChE and BChE), levels of antioxidant biomarkers (GSH), and mitochondrial functions, but markedly elevate the levels of oxidative stress biomarkers (MDA) and mitochondrial toxicity. Almost all of the previously mentioned parameters (especially mitochondrial toxicity) were retrieved by betanin, vitamin D, and thymoquinone compared to Ara-C group. These findings conclusively indicate that betanin, vitamin D, and thymoquinone administration provide adequate protection against Ara-C-induced neurotoxicity through modulations of oxidative, antioxidant activities, and mitochondrial protective (mitoprotective) effects.

The Role of Maternal Vitamin D Deficiency in Offspring Obesity: A Narrative Review

Currently, vitamin D (VD) deficiency during pregnancy is widespread globally, causing unfavorable pregnancy outcomes for both mothers and infants for a longer time than expected, based on the Developmental Origins of Health and Disease (DOHaD) theory. As VD plays a key role in maintaining normal glucose and lipid metabolism, maternal VD deficiency may lead to obesity and other obesity-related diseases among offspring later in life. This review mainly focuses on the effect of maternal VD deficiency on offspring lipid metabolism, reviewing previous clinical and animal studies to determine the effects of maternal VD deficit on offspring obesity and potential mechanisms involved in the progression of offspring obesity. Emerging clinical evidence shows that a low VD level may lead to abnormal growth (either growth restriction or largeness for gestational age) and lipid and glucose metabolism disorders in offspring. Here, we also outline the link between maternal VD deficiency and life-long offspring effects, including the disorder of adipogenesis, the secretion of adipocytokines (including leptin, resistin, and adiponectin), activated systemic inflammation, increased oxidative reactions in adipose tissue, insulin resistance, and abnormal intestinal gut microbiota. Thus, there is an urgent need to take active steps to address maternal VD deficiency to relieve the global burden of obesity.

Non-Enzymatic Antioxidants against Alzheimer's Disease: Prevention, Diagnosis and Therapy

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive memory loss and cognitive decline. Although substantial research has been conducted to elucidate the complex pathophysiology of AD, the therapeutic approach still has limited efficacy in clinical practice. Oxidative stress (OS) has been established as an early driver of several age-related diseases, including neurodegeneration. In AD, increased levels of reactive oxygen species mediate neuronal lipid, protein, and nucleic acid peroxidation, mitochondrial dysfunction, synaptic damage, and inflammation. Thus, the identification of novel antioxidant molecules capable of detecting, preventing, and counteracting AD onset and progression is of the utmost importance. However, although several studies have been published, comprehensive and up-to-date overviews of the principal anti-AD agents harboring antioxidant properties remain scarce. In this narrative review, we summarize the role of vitamins, minerals, flavonoids, non-flavonoids, mitochondria-targeting molecules, organosulfur compounds, and carotenoids as non-enzymatic antioxidants with AD diagnostic, preventative, and therapeutic potential, thereby offering insights into the relationship between OS and neurodegeneration.

Vitamin D, a Secosteroid Hormone and Its Multifunctional Receptor, Vitamin D Receptor, in Alzheimer's Type Neurodegeneration

Vitamin D is a secosteroid hormone exerting neurosteroid-like properties. Its well-known nuclear hormone receptor, and recently proposed as a mitochondrial transcription factor, vitamin D receptor, acts for its primary functions. The second receptor is an endoplasmic reticulum protein, protein disulfide isomerase A3 (PDIA3), suggested to act as a rapid response. Vitamin D has effects on various systems, particularly through calcium metabolism. Among them, the nervous system has an important place in the context of our subject. Recent studies have shown that vitamin D and its receptors have numerous effects on the nervous system. Neurodegeneration is a long-term process. Throughout a human life span, so is vitamin D deficiency. Our previous studies and others have suggested that the out-come of long-term vitamin D deficiency (hypovitaminosis D or inefficient utilization of vitamin D), may lead neurons to be vulnerable to aging and neurodegeneration. We suggest that keeping vitamin D levels at adequate levels at all stages of life, considering new approaches such as agonists that can activate vitamin D receptors, and utilizing other derivatives produced in the synthesis process with UVB are crucial when considering vitamin D-based intervention studies. Given most aspects of vitamin D, this review outlines how vitamin D and its receptors work and are involved in neurodegeneration, emphasizing Alzheimer's disease.

Nongenomic Activities of Vitamin D

Vitamin D shows a variety of pleiotropic activities which cannot be fully explained by the stimulation of classic pathway- and vitamin D receptor (VDR)-dependent transcriptional modulation. Thus, existence of rapid and nongenomic responses to vitamin D was suggested. An active form of vitamin D (calcitriol, 1,25(OH)₂D₃) is an essential regulator of calcium-phosphate homeostasis, and this process is tightly regulated by VDR genomic activity. However, it seems that early in evolution, the production of secosteroids (vitamin-D-like steroids) and their subsequent photodegradation served as a protective mechanism against ultraviolet radiation and oxidative stress. Consequently, direct cell-protective activities of vitamin D were proven. Furthermore, calcitriol triggers rapid calcium influx through epithelia and its uptake by a variety of cells. Subsequently, protein disulfide-isomerase A3 (PDIA3) was described as a membrane vitamin D receptor responsible for rapid nongenomic responses. Vitamin D was also found to stimulate a release of secondary massagers and modulate several intracellular processes-including cell cycle, proliferation, or immune responses-through wingless (WNT), sonic hedgehog (SSH), STAT1-3, or NF-kappaB pathways. Megalin and its coreceptor, cubilin, facilitate the import of vitamin D complex with vitamin-D-binding protein (DBP), and its involvement in rapid membrane responses was suggested. Vitamin D also directly and indirectly influences mitochondrial function, including fusion-fission, energy production, mitochondrial membrane potential, activity of ion channels, and apoptosis. Although mechanisms of the nongenomic responses to vitamin D are still not fully understood, in this review, their impact on physiology, pathology, and potential clinical applications will be discussed.

The role of vitamin D on redox regulation and cellular senescence

Vitamin D is considered an essential micronutrient for human health that is metabolized into a multifunctional secosteroid hormone. We can synthesize it in the skin through ultraviolet B (UVB) rays or acquire it from the diet. Its deficiency is a major global health problem that affects all ages and ethnic groups. Furthermore, dysregulation of vitamin D homeostasis has been associated with premature aging, driven by various cellular processes, including oxidative stress and cellular senescence. Various studies have shown that vitamin D can attenuate oxidative stress and delay cellular senescence, mainly by inducing the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and Klotho and improving mitochondrial homeostasis, proposing this vitamin as an excellent candidate for delaying aging. However, the mechanisms around these processes are not yet fully explored. Therefore, in this review, the effects of vitamin D on redox regulation and cellular senescence are discussed to propose new lines of research and clinical applications of vitamin D in the context of age-related diseases.

An Overview of the Current Known and Unknown Roles of Vitamin D3 in the Female Reproductive System: Lessons from Farm Animals, Birds, and Fish

Recent studies have clearly shown that vitamin D₃ is a crucial regulator of the female reproductive process in humans and animals. Knowledge of the expression of vitamin D₃ receptors and related molecules in the female reproductive organs such as ovaries, uterus, oviduct, or placenta under physiological and pathological conditions highlights its contribution to the proper function of the reproductive system in females. Furthermore, vitamin D₃ deficiency leads to serious reproductive disturbances and pathologies including ovarian cysts. Although the influence of vitamin D₃ on the reproductive processes of humans and rodents has been extensively described, the association between vitamin D₃ and female reproductive function in farm animals, birds, and fish has rarely been summarized. In this review, we provide an overview of the role of vitamin D₃ in the reproductive system of those animals, with special attention paid to the expression of vitamin D₃ receptors and its metabolic molecules. This updated information could be essential for better understanding animal physiology and overcoming the incidence of infertility, which is crucial for optimizing reproductive outcomes in female livestock.

The critical issue linking lipids and inflammation: Clinical utility of stopping oxidative stress

The formation of an atheroma begins when lipoproteins become trapped in the intima. Entrapped lipoproteins become oxidized and activate the innate immune system. This immunity represents the primary association between lipids and inflammation. When the trapping continues, the link between lipids and inflammation becomes chronic and detrimental, resulting in atherosclerosis. When entrapment ceases, the association between lipids and inflammation is temporary and healthy, and the atherogenic process halts. Therefore, the link between lipids and inflammation depends upon lipoprotein retention in the intima. The entrapment is due to electrostatic forces uniting apolipoprotein B to polysaccharide chains on intimal proteoglycans. The genetic transformation of contractile smooth muscle cells in the media into migratory secretory smooth muscle cells produces the intimal proteoglycans. The protein, platelet-derived growth factor produced by activated platelets, is the primary stimulus for this genetic change. Oxidative stress is the main stimulus to activate platelets. Therefore, minimizing oxidative stress would significantly reduce the retention of lipoproteins. Less entrapment decreases the association between lipids and inflammation. More importantly, it would halt atherogenesis. This review will analyze oxidative stress as the critical link between lipids, inflammation, and the pathogenesis of atherosclerosis. Through this perspective, we will discuss stopping oxidative stress to disrupt a harmful association between lipids and inflammation. Numerous therapeutic options will be discussed to mitigate oxidative stress. This paper will add a new meaning to the Morse code distress signal SOS-stopping oxidative stress.

Mitochondrial Dysfunction and Neurodegenerative Disorders: Role of Nutritional Supplementation

Mitochondrial dysfunction has been implicated in the pathogenesis of a number of neurodegenerative disorders, including Parkinson's disease, Alzheimer's disease, amyotrophic lateral sclerosis, multisystem atrophy, and progressive supranuclear palsy. This article is concerned specifically with mitochondrial dysfunction as defined by reduced capacity for ATP production, the role of depleted levels of key nutritionally related metabolites, and the potential benefit of supplementation with specific nutrients of relevance to normal mitochondrial function in the above neurodegenerative disorders. The article provides a rationale for a combination of CoQ10, B-vitamins/NADH, L-carnitine, vitamin D, and alpha-lipoic acid for the treatment of the above neurodegenerative disorders.

The Effect of Metabolites on Mitochondrial Functions in the Pathogenesis of Skeletal Muscle Aging

Sarcopenia is an age-related systemic disease characterized by skeletal muscle aging that generally severely affects the quality of life of elderly patients. Metabolomics analysis is a powerful tool for qualitatively and quantitatively characterizing the small molecule metabolomics of various biological matrices in order to clarify all key scientific problems concerning cell metabolism. The discovery of optimal therapy requires a thorough understanding of the cellular metabolic mechanism of skeletal muscle aging. In this review, the relationship between skeletal muscle mitochondria, amino acid, vitamin, lipid, adipokines, intestinal microbiota and vascular microenvironment has been separately reviewed from the perspective of metabolomics, and a new therapeutic direction has been suggested.

To identify the association between dietary vitamin D intake and serum levels and risk or prognostic factors for melanoma-systematic review and meta-analysis

OBJECTIVE

To evaluate the association of serum vitamin D levels and dietary intake with melanoma risk and prognostic factors.

METHODS

Two independent investigators systematically searched PubMed, Embase and ISI Web of Knowledge (Thomson Scientific Technical Support, New York) databases for eligible studies published between January 1992 and September 2020 using the following combinations of search terms: (vitamin D, or 25-hydroxyvitamin D) AND (melanoma, malignant melanoma, cutaneous melanoma, or cutaneous malignant melanoma). Articles not written in English but with English titles and abstracts were also checked. We obtained the full text of all potentially eligible articles, and reference lists of all studies retrieved at the first stage were also checked to identify other eligible papers. Review articles not reporting original data were excluded, but their reference lists were inspected.

RESULTS

Six studies including 212 723 cases reported the association between dietary intake of 25(OH) D serum levels and melanoma risk. The total relative risk for the comparison between the highest and lowest quantiles of the distribution of vitamin D intake was 1.10 (95% CI 0.96 to 1.26) with I ²=56%. Another six studies including 12 297 cases evaluated the association between serum vitamin D levels and melanoma risk. The total relative risk for the comparison of serum vitamin D levels between the highest and lowest quantiles was 1.12 (95% CI 0.53 to 2.35) with I ²=91%. Four studies with 2105 cases investigated the association between serum 25(OH)D (nmol/L) and Breslow thickness, three of which found an inverse association between serum 25(OH)D (nmol/L) and melanoma thickness.

CONCLUSIONS

Vitamin D intake and serum 25(OH)D levels were not closely related with melanoma risk, but an inverse association between serum 25(OH)D levels with melanoma thickness was discovered. As the positive correlation between melanoma thickness and melanoma mortality has been recognised, hence it is concluded that a moderate dietary vitamin D supplement to avoid the serum 25(OH)D deficient might be beneficial to the long-term survival of patients with melanoma.

Vitamin D Signaling in Psoriasis: Pathogenesis and Therapy

Psoriasis is a systemic, chronic, immune-mediated disease that affects approximately 2–3% of the world’s population. The etiology and pathophysiology of psoriasis are still unknown, but the activation of the adaptive immune system with the main role of T-cells is key in psoriasis pathogenesis. The modulation of the local neuroendocrine system with the downregulation of pro-inflammatory and the upregulation of anti-inflammatory messengers represent a promising adjuvant treatment in psoriasis therapies. Vitamin D receptors and vitamin D-mediated signaling pathways function in the skin and are essential in maintaining the skin homeostasis. The active forms of vitamin D act as powerful immunomodulators of clinical response in psoriatic patients and represent the effective and safe adjuvant treatments for psoriasis, even when high doses of vitamin D are administered. The phototherapy of psoriasis, especially UVB-based, changes the serum level of 25(OH)D, but the correlation of 25(OH)D changes and psoriasis improvement need more clinical trials, since contradictory data have been published. Vitamin D derivatives can improve the efficacy of psoriasis phototherapy without inducing adverse side effects. The anti-psoriatic treatment could include non-calcemic CYP11A1-derived vitamin D hydroxyderivatives that would act on the VDR or as inverse agonists on RORs or activate alternative nuclear receptors including AhR and LXRs. In conclusion, vitamin D signaling can play an important role in the natural history of psoriasis. Selective targeting of proper nuclear receptors could represent potential treatment options in psoriasis.

Pivotal role of vitamin D in mitochondrial health, cardiac function, and human reproduction

Vitamin D, a secosteroid hormone, appears to have significant beneficial effects on various physiological systems, including the musculoskeletal system. Vitamin D assists in the regulation of numerous critical biological functions and physiological processes in humans, including inflammation, oxidative stress, and mitochondrial respiration, and is also linked to cardiac diseases. It is also reported that vitamin D plays a central role in molecular and cellular mechanisms, which reduce oxidative stress, and tissue damage and regulate cellular health. On the other side, hypovitaminosis D reduces mitochondrial activity and increases oxidative stress and inflammation in the body. Hypervitaminosis D increases the prevalence and severity of cellular damage. It has also been reported that vitamin D is involved in many functions of the reproductive system in human and critically play an important role in the reproductive tissues of women and men. Its role is very well defined, starting from female menarche to menopause, pregnancy, and lactation, and finally in male fertility. Hence, the appropriate amount of vitamin D is necessary to maintain the normal function of cell organelles. Based on recent studies, it is understood that vitamin D is involved in the biological activities of mitochondria in cells, especially in cardiomyocytes. In this review, we emphasized the role of vitamin D in mitochondrial respiration, which could significantly influence heart health and human reproduction.

Paricalcitol Attenuates Metabolic Syndrome-Associated Heart Failure through Enhanced Mitochondrial Fusion

Objectives

Transition from cardiac hypertrophy to failure involves adverse metabolic reprogramming involving mitochondrial dysfunction. We have earlier shown that vitamin D deficiency induces heart failure, at least in part, through insulin resistance. However, whether activation of vitamin D receptor (VDR) can attenuate heart failure and underlying metabolic phenotype requires investigation. Thus, we aimed to assess the cardioprotective potential of paricalcitol, a vitamin D receptor-activator, against cardiac hypertrophy and failure in high-fat high-fructose-fed rats.

Methods

Male Sprague Dawley rats were fed control (Con) or high-fat high-fructose (HFHFrD) diet for 20 weeks. After 12 weeks, rats from HFHFrD group were divided into the following: HFHFrD, HFHFrD+P (paricalcitol i.p. 0.08 μg/kg/day) and HFHFrD+E (enalapril maleate i.p. 10 mg/kg/day). Intraperitoneal glucose tolerance test, blood pressure measurement, and 2D echocardiography were performed. Cardiac fibrosis was assessed by Masson's trichrome staining of paraffin-embedded heart sections. Mitochondrial DNA and proteins, and citrate synthase activity were measured in rat hearts. VDR was silenced in H9c2 cardiomyoblasts, and immunoblotting was performed.

Results

Paricalcitol improved glucose tolerance, serum lipid profile, and blood pressure in high-fat high-fructose-fed rats. Paricalcitol reduced cardiac wall thickness and increased ejection fraction in high-fat high-fructose-fed rats but had no effect on perivascular fibrosis. PGC1-α was upregulated in the HFHFrD+P group compared to the HFHFrD group, but there was no significant difference in mitochondrial content. Citrate synthase activity was significantly higher in the HFHFrD+P group compared to the HFHFrD group. Rat hearts of the HFHFrD+P group had significantly higher expression of mitofusins. H9c2 cells with VDR knockdown showed significantly lower expression of Mfn2. Improvement in the HFHFrD+P group was comparable with that in the HFHFrD+E group.

Conclusions

Paricalcitol reverses cardiac dysfunction in rats with metabolic syndrome by enhancing mitochondrial fusion. We demonstrate repurposing potential of the drug currently used in end-stage kidney disease.

Vitamin D Supplementation Improves Mitochondrial Function and Reduces Inflammation in Placentae of Obese Women

Background

About 30% of women entering pregnancy in the US are obese. We have previously reported mitochondrial dysregulation and increased inflammation in the placentae of obese women. Vitamin D (VitD) is a major player in calcium uptake and was shown to modulate mitochondrial respiration and the immune/inflammation system. Studies show decreased VitD levels in obese individuals; however, the effect of maternal obesity on VitD metabolism and its association with placental function remains understudied.

Methods

Maternal and cord blood plasma and placental samples were collected upon C-section from normal-weight (NW, body mass index [BMI]<25) and obese (OB, BMI>30) women with uncomplicated pregnancies at term. We measured 25(OH)D3 (calcidiol) levels in maternal and cord blood plasma using ELISA. We assessed the expression of CYP27B1, an activator of calcidiol, and Vitamin D receptor (VDR) in placentae from NW and OB, and women with gestational diabetes and preeclampsia. In addition, we examined the effects of VitD supplementation on mitochondrial function and inflammation in trophoblasts from NW and OB, using the Seahorse Bioanalyzer and Western blot, respectively.

Results

Vitamin D levels in blood from OB but not NW women and in cord blood from babies born to NW and OB women showed a significant inverse correlation with maternal pre-pregnancy BMI (r=-0.50, p<0.1 and r=-0.55, p=0.004 respectively). Cord plasma VitD levels showed a positive correlation with placental efficiency, i.e., the ratio between fetal and placental weight, as well as with maternal blood VitD levels (r=0.69 and 0.83 respectively, p<0.00). While we found no changes in CYP27B1 in OB vs. NW women, VDR expression were decreased by 50% (p<0.03) independent of fetal sex. No changes in VDR expression relative to BMI-matched controls were observed in the placentae of women with gestational diabetes or preeclampsia. Cytotrophoblasts isolated from placentae of OB women showed a dose-dependent increase in VDR expression after 24-hour treatment with calcitriol (10 nM and 100 nM), an active form of VitD. Trophoblasts isolated from OB women and treated with calcitriol improved mitochondrial respiration (p<0.05). We also found a two-fold increase in expression of the NLRP3 inflammasome and the pro-inflammatory cytokine IL-18 in trophoblasts isolated from placentae of OB women (p<0.05), with IL-18 expression being reversed by calcitriol treatment (100 nM).

Conclusions

We show that VitD deficiency is at least partially responsible for mitochondrial dysfunction and increased inflammation in the placentae of obese women. Vitamin D supplementation could be beneficial in improving placental dysfunction seen in obese women.

The Vitamin D/Vitamin D receptor (VDR) axis in muscle atrophy and sarcopenia

Muscle atrophy and sarcopenia (the term given to the age-related decline in muscle mass and function), influence an individuals risk of falls, frailty, functional decline, and, ultimately, impaired quality of life. Vitamin D deficiency (low serum levels of 25-hydroxyvitamin D (25(OH)D₃)) has been reported to impair muscle strength and increase risk of sarcopenia. The mechanisms that underpin the link between low 25(OH)D₃ and sarcopenia are yet to be fully understood but several lines of evidence have highlighted the importance of both genomic and non-genomic effects of active vitamin D (1,25-dihydroxyvitamin D (1,25(OH)₂D₃)) and its nuclear vitamin D receptor (VDR), in skeletal muscle functioning. Studies in vitro have demonstrated a key role for the vitamin D/VDR axis in regulating biological processes central to sarcopenic muscle atrophy, such as proteolysis, mitochondrial function, cellular senescence, and adiposity. The aim of this review is to provide a mechanistic overview of the proposed mechanisms for the vitamin D/VDR axis in sarcopenic muscle atrophy.

Insights Into Vascular Anomalies, Cancer, and Fibroproliferative Conditions: The Role of Stem Cells and the Renin-Angiotensin System

Cells exhibiting embryonic stem cell (ESC) characteristics have been demonstrated in vascular anomalies (VAs), cancer, and fibroproliferative conditions, which are commonly managed by plastic surgeons and remain largely unsolved. The efficacy of the mTOR inhibitor sirolimus, and targeted therapies that block the Ras/BRAF/MEK/ERK1/2 and PI3KCA/AKT/mTOR pathways in many types of cancer and VAs, further supports the critical role of ESC-like cells in the pathogenesis of these conditions. ESC-like cells in VAs, cancer, and fibroproliferative conditions express components of the renin-angiotensin system (RAS) – a homeostatic endocrine signaling cascade that regulates cells with ESC characteristics. ESC-like cells are influenced by the Ras/BRAF/MEK/ERK1/2 and PI3KCA/AKT/mTOR pathways, which directly regulate cellular proliferation and stemness, and interact with the RAS at multiple points. Gain-of-function mutations affecting these pathways have been identified in many types of cancer and VAs, that have been treated with targeted therapies with some success. In cancer, the RAS promotes tumor progression, treatment resistance, recurrence, and metastasis. The RAS modulates cellular invasion, migration, proliferation, and angiogenesis. It also indirectly regulates ESC-like cells via its direct influence on the tissue microenvironment and by its interaction with the immune system. In vitro studies show that RAS inhibition suppresses the hallmarks of cancer in different experimental models. Numerous epidemiological studies show a reduced incidence of cancer and improved survival outcomes in patients taking RAS inhibitors, although some studies have shown no such effect. The discovery of ESC-like cells that express RAS components in infantile hemangioma (IH) underscores the paradigm shift in the understanding of its programmed biologic behavior and accelerated involution induced by β-blockers and angiotensin-converting enzyme inhibitors. The findings of SOX18 inhibition by R-propranolol suggests the possibility of targeting ESC-like cells in IH without β-adrenergic blockade, and its associated side effects. This article provides an overview of the current knowledge of ESC-like cells and the RAS in VAs, cancer, and fibroproliferative conditions. It also highlights new lines of research and potential novel therapeutic approaches for these unsolved problems in plastic surgery, by targeting the ESC-like cells through manipulation of the RAS, its bypass loops and converging signaling pathways using existing low-cost, commonly available, and safe oral medications.

The Role of Vitamin D in Supporting Health in the COVID-19 Era

The genomic activity of vitamin D is associated with metabolic effects, and the hormone has a strong impact on several physiological functions and, therefore, on health. Among its renowned functions, vitamin D is an immunomodulator and a molecule with an anti-inflammatory effect, and, recently, it has been much studied in relation to its response against viral infections, especially against COVID-19. This review aims to take stock of the correlation studies between vitamin D deficiency and increased risks of severe COVID-19 disease and, similarly, between vitamin D deficiency and acute respiratory distress syndrome. Based on this evidence, supplementation with vitamin D has been tested in clinical trials, and the results are discussed. Finally, this study includes a biochemical analysis on the effects of vitamin D in the body's defense mechanisms against viral infection. In particular, the antioxidant and anti-inflammatory functions are considered in relation to energy metabolism, and the potential, beneficial effect of vitamin D in COVID-19 is described, with discussion of its influence on different biochemical pathways. The proposed, broader view of vitamin D activity could support a better-integrated approach in supplementation strategies against severe COVID-19, which could be valuable in a near future of living with an infection becoming endemic.

Targeting mitochondria in dermatological therapy: Beyond oxidative damage and skin aging

INTRODUCTION

The analysis of the role of the mitochondria in oxidative damage and skin aging is a significant aspect of dermatological research. Mitochondria generate most reactive oxygen species (ROS); however, excessive ROS are cytotoxic and DNA-damaging and promote (photo-)aging. ROS also possesses key physiological and regulatory functions and mitochondrial dysfunction is prominent in several skin diseases including skin cancers. Although many standard dermatotherapeutics modulate mitochondrial function, dermatological therapy rarely targets the mitochondria. Accordingly, there is a rationale for "mitochondrial dermatology"-based approaches to be applied to therapeutic research.

AREAS COVERED

This paper examines the functions of mitochondria in cutaneous physiology beyond energy (ATP) and ROS production. Keratinocyte differentiation and epidermal barrier maintenance, appendage morphogenesis and homeostasis, photoaging and skin cancer are considered. Based on related PubMed search results, the paper evaluates thyroid hormones, glucocorticoids, Vitamin D3 derivatives, retinoids, cannabinoid receptor agonists, PPARγ agonists, thyrotropin, and thyrotropin-releasing hormone as instructive lead compounds. Moreover, the mitochondrial protein MPZL3 as a promising new drug target for future "mitochondrial dermatology" is highlighted.

EXPERT OPINION

Future dermatological therapeutic research should have a mitochondrial medicine emphasis. Focusing on selected lead agents, protein targets, in silico drug design, and model diseases will fertilize a mito-centric approach.