Topic Review
Vitamin D3 Hydroxyderivatives in Human
itamin D3 (D3) is produced in the skin in two steps. Initially there is a photochemical reaction caused by the action of UVB radiation (290–315 nm) on 7-dehydrocholesterol (7DHC) in which the B ring is broken producing pre-vitamin D3. In the second reaction, vitamin D3 is formed from pre-vitamin D3 by its thermal isomerization at 37 °C over several hours. Both the UVB intensity and the level of skin pigmentation affect the rate of vitamin D3 production. Vitamin D3 is a fat-soluble prohormonal secosteroid that has endocrine, paracrine and autocrine functions. Melanin absorbs UVB limiting the production of D3, and the same effect is achieved with clothing and sunscreen. Skin, more specifically the epidermis, has the full capacity to produce and activate vitamin D3.
  • 500
  • 07 Jul 2021
Topic Review
Vitamin D3 and Ischemic Stroke
Ischemic stroke is one of the major causes of death and permanent disability worldwide. The only efficient treatment to date is anticoagulant therapy and thrombectomy, which enable restitution of blood flow to ischemic tissues. Numerous promising neuroprotectants have failed in clinical trials. Given the complex pathomechanism of stroke, a multitarget pharmacotherapy seems a more rational approach in stroke prevention and treatment than drugs acting on single molecular targets. Vitamin D3 has emerged as a potential treatment adjunct for ischemic stroke, as it interferes with the key prosurvival pathways and shows neuroprotective, anti-inflammatory, regenerative and anti-aging properties in both neuronal and vascular tissue.
  • 431
  • 28 Nov 2022
Topic Review
Vitamin D, Sun Exposure and Skin Cancer
The current vitamin D deficiency epidemic is accompanied by an increase in endemic skin cancer. Ultraviolet (UV) exposure (neither artificial nor natural) is not the ideal source to synthesize vitamin D. There is conflicting epidemiological evidence regarding vitamin D, non-melanoma skin cancer (NMSC), and cutaneous melanoma (CMM), confounded by the effect of sun exposure and other factors. 
  • 386
  • 29 Mar 2022
Topic Review
Vitamin D, microbiome, and IBD
Inflammatory bowel disease (IBD) is a chronic inflammation of the gastrointestinal tract (GIT), including Crohn’s disease (CD) and ulcerative colitis (UC), which differ in the location and lesion extensions. Both diseases are associated with microbiota dysbiosis, with a reduced population of butyrate-producing species, abnormal inflammatory response, and micronutrient deficiency (e.g., vitamin D hypovitaminosis). Vitamin D (VitD) is involved in immune cell differentiation, gut microbiota modulation, gene transcription, and barrier integrity. Vitamin D receptor (VDR) regulates the biological actions of the active VitD (1α,25-dihydroxyvitamin D3), and is involved in the genetic, environmental, immune, and microbial aspects of IBD. VitD deficiency is correlated with disease activity and its administration targeting a concentration of 30 ng/mL may have the potential to reduce disease activity. Moreover, VDR regulates functions of T cells and Paneth cells and modulates release of antimicrobial peptides in gut microbiota-host interactions. Meanwhile, beneficial microbial metabolites, e.g., butyrate, upregulate the VDR signaling.
  • 735
  • 31 Jan 2021
Topic Review
Vitamin D—Practical Considerations and Clinical Guidance
Empirical evidence establishes the connection between exposure and clinical outcomes. Clinical studies show that chronic diseases and infections can be prevented by proactively correcting vitamin D deficiency in individuals who are vitamin D deficient, and in the community. In RCTs, with proper daily or once-a-week vitamin D supplementation in the intervention group, the serum 25(OH)D concentration must be meaningfully increased to the above pre-planned level to ensure the validity of the clinical study. Clinical outcomes correlate well with the serum 25(OH)D concentrations but not necessarily with the administered doses. It is a common error by researchers and healthcare workers to assume that the amount taken automatically produces the stipulated serum levels.
  • 533
  • 01 Nov 2023
Topic Review
Vitamin D with Ovarian Reserve Markers and Depression
Since the identification of vitamin D receptors in both the female reproductive tract and the central nervous system, further data have shown that vitamin D is involved in the processes of reproductive and mental health.
  • 129
  • 05 Jan 2024
Topic Review
Vitamin D Target Genes
The biologically active form of vitamin D3, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3), modulates innate and adaptive immunity via genes regulated by the transcription factor vitamin D receptor (VDR). In order to identify the key vitamin D target genes involved in these processes, transcriptome-wide datasets were compared, which were obtained from a human monocytic cell line (THP-1) and peripheral blood mononuclear cells (PBMCs) treated in vitro by 1,25(OH)2D3, filtered using different approaches, as well as from PBMCs of individuals supplemented with a vitamin D3 bolus. The led to the genes ACVRL1, CAMP, CD14, CD93, CEBPB, FN1, MAPK13, NINJ1, LILRB4, LRRC25, SEMA6B, SRGN, THBD, THEMIS2 and TREM1. Public epigenome- and transcriptome-wide data from THP-1 cells were used to characterize these genes based on the level of their VDR-driven enhancers as well as the level of the dynamics of their mRNA production.
  • 1.0K
  • 15 Apr 2022
Topic Review
Vitamin D Supplementation on Fatigue in Multiple Sclerosis
Multiple sclerosis (MS) is an autoimmune and inflammatory chronic disease of the central nervous system that constitutes one of the leading causes of disability among young adults. Multiple sclerosis can produce a variety of symptoms, such as fatigue, blurred vision, optic neuritis, weakness, dizziness, balance disturbances, cognitive decline, and problems with bladder control, as well as an increased risk of depression and anxiety. Fatigue is one of the most common and disabling symptoms and can be described as a subjective lack of physical and/or mental energy that interferes with usual activities. 
  • 316
  • 04 Jul 2023
Topic Review
Vitamin D Status and Allergy Outcomes
The very early onset of allergic diseases points to the specific vulnerability of the developing immune system to environmental changes and the development of primary intervention strategies is crucial to address this unparalleled burden. Vitamin D is known to have immunomodulatory functions. While allergic disease is multifactorial, associations with reduced sunlight exposure have led to the hypothesis that suboptimal vitamin D levels during critical early periods may be one possible explanation. Interventions to improve vitamin D status, especially in early life, may be the key to allergic disease prevention.
  • 400
  • 28 Apr 2022
Topic Review
Vitamin D Signaling in Gastro-Rheumatology
Vitamin D has been recently pointed out, and abnormalities of the vitamin D axis have been described in both in vitro and in vivo models of inflammatory bowel diseases (IBD) and arthritis.
  • 383
  • 29 Apr 2021
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