The Vitamin D3 Pathway in Human Skin and its Role for Regulation of Biological Processes

Nonaqueous Capillary Electrophoretic Separation of Analogs of (24R)-1,24-Dihydroxyvitamin D3 Derivative as Predicted by Quantum Chemical Calculations

Nonaqueous capillary electrophoretic (NACE) separation was obtained of analogs of (24R)-1,24-dihydroxyvitamin D₃ derivative (calcipotriol) as predicted by quantum chemical calculations supported by the density functional theory (DFT). Among the key electronic properties investigated, absolute values of the dipole polarizability and energy gap between HOMO and LUMO molecular orbitals of the analog molecules differ significantly for particular analogs, and there is a direct relationship with their electrophoretic migration time. These differences and relationships suggest that the structurally related analogs should be separable in the electrostatic field. Indeed, the robust, sensitive, and rapid NACE method was first developed for the identification and determination of the anticancer analog of calcipotriol (coded PRI-2205) and its process-related impurities (coded PRI-2201, PRI-2203, and PRI-2204) in organic and aqueous biological solutions. The direct relation between the calculated electronic properties of the analogs and the experimental electrophoretic migration time could be a promising prospect for theoretically predicting the electrophoretic separations.

The Effect of Narrow-Band Ultraviolet B Phototherapy on Free and Total Vitamin D Serum Levels in Mild to Severe Plaque Psoriasis

Vitamin D plays an important role in skin inflammation in psoriasis. The beneficial effects of ultraviolet light B (UVB) phototherapy in psoriasis are partly attributed to UVB-induced increase of vitamin D levels. In clinical practice, total 25-hydroxy vitamin D (25(OH)D) levels are measured to assess sufficiency, but it might be more accurate to measure free 25(OH)D levels. The aim of this study was to measure free serum 25(OH)D levels in psoriasis patients before and after phototherapy and to investigate if free 25(OH)D correlates stronger to disease severity than total 25(OH)D. Twenty adults (>18 years) with psoriasis were included for treatment with narrow-band UVB (NB-UVB) phototherapy for 10-12 weeks. Psoriasis Area and Severity Index (PASI) and Visual Analogue Scale (VAS) were used to assess disease severity. Serum levels of total 25(OH)D, free 25(OH)D, and 1,25(OH)₂D were measured before and after NB-UVB. Total 25(OH)D, free 25(OH)D, 1,25(OH)₂D and the percentage of free 25(OH)D increased after NB-UVB, and PASI and VAS improved. The increase in total and free 25(OH)D remained significant when stratifying for vitamin D confounders. No correlations between disease severity and vitamin D levels were found. Total and free 25(OH)D levels were positively correlated before and after NB-UVB. NB-UVB is an effective treatment for mild to severe plaque psoriasis and increases not only total but also free 25(OH)D levels, as well as the percentage of free 25(OH)D, suggesting an increased bioavailability of skin-produced vitamin D.

Molecular insights into the pathogenic impact of vitamin D deficiency in neurological disorders

Neurological disorders are the major cause of disability, leading to a decrease in quality of life by impairing cognitive, sensorimotor, and motor functioning. Several factors have been proposed in the pathogenesis of neurobehavioral changes, including nutritional, environmental, and genetic predisposition. Vitamin D (VD) is an environmental and nutritional factor that is widely distributed in the central nervous system's subcortical grey matter, neurons of the substantia nigra, hippocampus, thalamus, and hypothalamus. It is implicated in the regulation of several brain functions by preserving neuronal structures. It is a hormone rather than a nutritional vitamin that exerts a regulatory role in the pathophysiology of several neurological disorders, including Alzheimer's disease, Parkinson's disease, epilepsy, and multiple sclerosis. A growing body of epidemiological evidence suggests that VD is critical in neuronal development and shows neuroprotective effects by influencing the production and release of neurotrophins, antioxidants, immunomodulatory, regulation of intracellular calcium balance, and direct effect on the growth and differentiation of nerve cells. This review provides up-to-date and comprehensive information on vitamin D deficiency, risk factors, and clinical and preclinical evidence on its relationship with neurological disorders. Furthermore, this review provides mechanistic insight into the implications of vitamin D and its deficiency on the pathogenesis of neurological disorders. Thus, an understanding of the crucial role of vitamin D in the neurobiology of neurodegenerative disorders can assist in the better management of vitamin D-deficient individuals.

Vitamin D, Cholesterol, and DXA Value Relationship with Bimaxillary Cone Beam CT Values

We evaluated the correlation that Vitamin D (Vit D), cholesterol levels, and T- and Z-scores of dual-energy X-ray absorptiometry (DXA) scans have with cone beam computed tomography values assessed in the anterior and posterior regions of maxillary and mandibular jaws. In total, 187 patients were recruited for this clinical study. Patients’ ages ranged between 45 and 65 years. Patients with valid DXA results, serum Vit D and cholesterol levels, and no evidence of bone disorders in the maxilla or mandibular region were included in the study and grouped in the control (non-osteoporosis) and case (osteoporosis) groups. Patients with a history of medical or dental disease that might complicate the dental implant therapy, chronic alcohol users, and patients who took calcium or Vit D supplements were excluded. The outcome variables assessed in the investigation were Vit D, cholesterol, Z-values, and cone beam computed tomography values. Regarding the case group, a significant (p < 0.05) inverse relationship was observed between Vit D and cholesterol. Although insignificant (p > 0.05), a positive relationship was found between Vit D and the cone beam computed tomography values in all regions of the jaws, except the mandibular posterior region (p < 0.05). Pearson correlation analysis was carried out. Vit D and cholesterol showed a statistically insignificant (p > 0.05) negative association with the cone beam computed tomography values in all regions of the jaws. However, the Z-values were highly correlated with the cone beam computed tomography values in all regions of the jaws (r > 7, p < 0.05). Vit D, cholesterol levels, and Z-values in women and men from young adulthood to middle age (45–65) were related with the cone beam computed tomography values of the jaws.

Does vitamin D have an effect on osseointegration of dental implants? A systematic review

Purpose

The aim of this study was to systematically review the available evidence to evaluate the efficacy of vitamin D supplementation or vitamin D depletion on the osseointegration of implants in animals and humans.

Methods

The focus questions addressed were “Do vitamin D deficient subjects treated with (dental) implants have an inferior osseointegration than subjects with adequate serum vitamin D level?” and “Do vitamin D supplemented subjects treated with (dental) implants have a superior osseointegration than subjects with adequate serum vitamin D level?” Humans and animals were considered as subjects in this study. Databases were searched from 1969 up to and including March 2021 using different combination of the following terms: “implant”, “bone to implant contact”, “vitamin D” and “osseointegration”. Letters to the editor, historic reviews, commentaries and articles published in languages other than English and German were excluded. The pattern of the present systematic review was customize to primarily summarize the pertinent data.

Results

Thirteen experimental studies with animals as subject, two clinical studies and three case reports, with humans as subjects, were included. The amount of inserted titanium implants ranged between 24 and 1740. Results from three animal studies showed that vitamin D deficiency has a negative effect on new bone formation and/or bone to implant contact (BIC). Eight animal studies showed that vitamin D supplementation has a enhancing effect on BIC and/or new bone formation around implants. Furthermore, enhancing the impact of vitamin D supplementation on the osseointegration of implants in subjects with diabetes mellitus, osteoporosis and chronic kidney disease (CKD) were assessed. Studies and case reports involving human subjects showed that patients with a low serum vitamin D level have a higher tendency to exhibit an early dental implant failure. When supplemented with vitamin D the osseointegration was successful in the case reports and a beneficial impact on the changes in the bone level during the osseointegration were determined.

Conclusions

Vitamin D deficiency seems to have a negative effect on the osseointegration of implants in animals. The supplementation of vitamin D appears to improve the osseointegration in animals with systemic diseases, such as vitamin D deficiency, diabetes mellitus, osteoporosis, and CKD. Slight evidence supports the hypothesis that humans similarly benefit from vitamin D supplementation in terms of osseointegration. Further investigation is required to maintain these assumptions.

7-Dehydrocholesterol Encapsulated Polymeric Nanoparticles As a Radiation-Responsive Sensitizer for Enhancing Radiation Therapy

Therapeutics that can be activated by radiation in situ to enhance the efficacy of radiotherapy are highly desirable. Herein, 7-Dehydrocholesterol (7-DHC), a biosynthetic precursor of cholesterol, as a radiosensitizer, exploiting its ability to propagate the free radical chain reaction is explored. The studies show that 7-DHC can react with radiation-induced reactive oxygen species and in turn promote lipid peroxidation, double-strand breaks, and mitochondrial damage in cancer cells. For efficient delivery, 7-DHC is encapsulated into poly(lactic-co-glycolic acid) nanoparticles, forming 7-DHC@PLGA NPs. When tested in CT26 tumor bearing mice, 7-DHC@PLGA NPs significantly enhanced the efficacy of radiotherapy, causing complete tumor eradication in 30% of the treated animals. After treatment, 7-DHC is converted to cholesterol, causing no detectable side effects or hypercalcemia. 7-DHC@PLGA NPs represent a radiation-responsive sensitizer with great potential in clinical translation.

Vitamin D Supplementation for Prevention of Dental Implant Failure: A Systematic Review

Background

Many factors play a significant role in osseointegration and healing after dental implant insertion and restoration. Some factors are related to dental biomaterials, such as the dental implant, prosthesis, and grafting materials. Other factors can be connected to operator skills and accumulated experience. Local and systemic patient-related factors are crucial in determining the success of the dental implant. Thorough examination and analysis of local factors using available examination tools are vital to prepare the implant candidate for such treatment. The patient's systemic condition directly affects the healing of the dental implant. One of the most overlooked systemic factors is the patients' vitamin D level, which influences bone formation around the implant and subsequent osseointegration. The current review examined the available literature regarding the association between vitamin D supplementation and dental implant osseointegration.

Methods

Data of this review were derived from recent research available on PubMed, Google Scholar, and Scopus. Inclusion criteria were the relation between the vitamin D serum and dental implant osseointegration or failure. The Systematic Reviews and Meta-Analyses (PRISMA) checklist was followed to perform the review. The study's outcome was the need for vitamin D supplementation to prevent implant failure.

Results

Five human studies (including case reports, case series, and retrospective studies) and six animal studies. All included studies discussed the relationship between vitamin D, early dental implant failure, and bone implant contact. Three retrospective studies found no significant relationship between vitamin D supplementation and EDIFs in humans. On the other hand, one retrospective study showed a significant relationship in humans. A case report and case series claimed that the implant was successfully placed after vitamin D supplementation. A total of four animal studies showed a significant relationship between vitamin D supplementation and osseointegration of the dental implant. Two animal studies showed no significant association.

Conclusion

To ensure optimal treatment outcomes, it is recommended to supplement the patient with vitamin D if the serum level is not within the normal range. Further clinical studies and case reports are needed to confirm the association between serum vitamin D levels and osseointegration.

Topical Application of Vitamin D3-Loaded Hybrid Nanosystem to Offset Imiquimod-Induced Psoriasis

Lipid-polymer hybrid nanoparticles display several benefits over either lipid and/or polymer based systems with respect to enhanced drug loading, good colloidal stability, sustained release profile, and high cellular uptake. The present work rivets on development and evaluation of vitamin D₃-loaded monolithic lipid-polymer hybrid nanoparticles (VD3/LPHNPs) for their in vivo anti-psoriatic efficacy. These LPHNPs were prepared using a hot homogenization method and exhibited spherical morphology with a lower particle size (123.1 nm) with narrow PDI (0.234) and efficient encapsulation (76.80%). Further, these LPHNPs demonstrated a sustained release profile of VD3 for up to 3 days following a Korsemeyer-Peppas release model. Further, VD3/LPHNPs were formulated into a topical gel containing 0.005% w/w of VD3. Rheological data suggested that the product exhibited non-newtonian flow properties with characteristic shear-thinning and variable thixotropy features that are desirable for topical formulation. The successful formation of gel structure and its long-term stability were confirmed from the oscillatory studies such as amplitude and frequency sweep tests. In vivo efficacy assessment in imiquimod-induced psoriatic mouse model demonstrated enhanced anti-psoriatic activity of VD3 with improved PASI score when delivered as LPHNPs gel as compared to the free VD3 gel that were further supported by histopathology and immunohistochemistry.

Is there a Relationship Between Vitamin D and Endometriosis? An Overview of the Literature

BACKGROUND

Vitamin D is involved in the physiological functions of several tissues, however, its deficiency may contribute to the development of various disorders. Recent research has been focusing on the role of vitamin D in the pathogenesis of endometriosis based on the evidence of the presence of vitamin D receptor and the enzymes required for vitamin D synthesis in the ectopic endometrium. Endometriosis, defined as the presence of endometrial glands and stroma in ectopic locations, is considered an estrogen-dependent disease and Vitamin D seems to have a role in modulation of the inflammatory state and proliferation of endometriotic cells.

OBJECTIVE

This study aimed to review the available literature regarding the relationship between vitamin D and endometriosis as well as the effects of vitamin D supplementation.

METHODS

A search on PubMed database has been performed.

RESULTS

The relationship between endometriosis and Vitamin D has been analyzed through the evaluation of vitamin D serum level, the polymorphism of vitamin D receptor and the role of vitamin D-binding protein in patient with endometriosis. The possible role of Vitamin D in the endometriosis therapy has also been investigated, in particular, the effect of vitamin D on pain relief, on endometriotic lesion in vitro and in rat models and in addition to a future target immunotherapy.

CONCLUSION

Although promising, the data analyzed are not sufficient to evidence a cause-effect relationship between VD status and endometriosis, therefore further studies are needed in order to better clarify the association between vitamin D and endometriosis, especially in the context of the possibility of new treatment options.

Reduced Dietary Calcium and Vitamin D Results in Preterm Birth and Altered Placental Morphogenesis in Mice During Pregnancy

Vitamin D and calcium are essential micronutrients for reproductive success. Vitamin D deficiency during pregnancy is associated with increased risk of pregnancy complications including pre-eclampsia and preterm birth (PTB). However, inconsistencies in the literature reflect uncertainties regarding the true biological importance of vitamin D but may be explained by maternal calcium intakes. We aimed to determine whether low dietary consumption of calcium along with vitamin D deficiency had an additive effect on adverse pregnancy outcome by investigating placental morphogenesis and foetal growth in a mouse model. Female mice were randomly assigned to one of four diets: control-fed (+Ca+VD), reduced vitamin D only (+Ca-VD), reduced calcium only (-Ca+VD) and reduced calcium and vitamin D (-Ca-VD), and sacrificed at gestational day (GD) 18.5. Maternal serum 25-hydroxyvitamin D (25(OH)D₃) levels were lower in each reduced diet group when compared with levels in +Ca+VD-fed mice. While the pregnancy rate did not differ between groups, in the -Ca-VD-fed group, 55% (5 out of 9 pregnant of known gestational age) gave birth preterm (<GD18.5). Of the -Ca-VD animals that gave birth at GD18.5, mean foetal weight increased by 8% when compared with +Ca+VD (P < 0.05) which was associated with increased placental efficiency (P = 0.05) as a result of changes to the placental labyrinth microstructure. In conclusion, we observed an interactive effect of low calcium and vitamin D intake that may impact offspring phenotype and preterm birth rate supporting the hypothesis that both calcium and vitamin D status are important for a successful pregnancy.

Imaging of vitamin D in psoriatic skin using time-of-flight secondary ion mass spectrometry (ToF-SIMS): A pilot case study

Recently it has been recognized that there is a need of investigating in detail the vitamin D synthesis and metabolism directly in the skin with respect to its possible autocrine and paracrine actions. The potential effects the active metabolite of vitamin D exerts in pathological skin conditions like psoriasis needs to be clarified. Under ultraviolet B (UVB) irradiation skin can autonomously synthesize, activate and degrade vitamin D. In this pilot case study, we used for the first time Time-of-flight secondary ion mass spectrometry (ToF-SIMS) in the analysis of skin biopsies from a patient with psoriasis before and after UVB phototherapy. We were able to visualize vitamin D₃ and its metabolites in the skin and subcutaneous tissue. At the same time information about their localization at subcellular level and morphology of the skin was received. This study proves that ToF-SIMS is a promising powerful tool to be used when investigating vitamin D´s role in dermatological diseases through skin biopsies.

Awareness of Vitamin D Deficiency among the General Population in Jeddah, Saudi Arabia

Background

During the last decade, vitamin D status was a major concern in the health and biomedical fields. This study assessed the level of awareness and knowledge regarding vitamin D and investigated the factors associated with the level of awareness such as knowing general facts about vitamin D, sources, benefit, and consequences of its deficiency.

Methods

This cross-sectional study was conducted among the general population in Jeddah, Saudi Arabia, above the age of 18 years who were in 3 malls during the period of August and September 2017. A self-administrated questionnaire in paper forms was utilized and was divided into two parts to collect data. It was designed by the authors after revising the previous studies and validated by three pediatric consultants. An ethical approval was obtained from the ethical committee in King Abdulaziz University. We did an initial sample and tested it with the Cronbach test. The questionnaire had 2 parts with 19 questions. The first part was demographic information, and the second part was general information about vitamin D. An ethical approval was obtained from the ethical committee in King Abdulaziz University. Each participant received explanations about the aim of the study, and a verbal consent was taken from participants. The scoring system was as follows: for each right answer, 1 score was given and for wrong answer, 0 score was given, and the overall score was 14. The collected data were statistically analyzed using descriptive statistics using IBM SPSS statistics for windows version 20.0 (SPSS Inc., Chicago, IL).

Result

Out of 1022 participants, 472 (46.1%) were aged 18–28 years, 830 (82.1%) were of Saudi ethnicity, 702 (68.7%) had a university degree, 275 (26.9%) attended high school, more than half were married (55.6%), and 54.4% had children. The majority of the participants agreed that vitamin D is important in the maintenance of bone and tooth health (88.4%). It is important in the maintenance of calcium and phosphates (76.6%), and it strengthens immunity (69.4%). Of the total participants, 86.2% were aware that sunlight exposure encourages vitamin D production in the skin. The overall knowledge mean score was 5.9 ± 1.2 (39.3%).

Conclusion

This study highlighted a high level of inadequate knowledge of vitamin D deficiency among participants. There was a significant association between knowledge level and education level. The awareness of vitamin D deficiency is high regarding its benefits. The study revealed that participants who did not have children had the highest score for benefits. Nongovernment organizations and social workers may work together with government health-care organization to teach parents and children about the uses and benefits of vitamin D.

Predicting serum vitamin D concentrations based on self-reported lifestyle factors and personal attributes

Evidence supports the role of vitamin D in various conditions of development and ageing. Serum 25-hydroxyvitamin D (25(OH)D) is the best indicator for current vitamin D status. However, the cost of its measurement can be prohibitive in epidemiological research. We developed and validated multivariable regression models that quantified the relationships between vitamin D determinants, measured through an in-person interview, and serum 25(OH)D concentrations. A total of 200 controls participating in a population-based case-control study in Montreal, Canada, provided a blood specimen and completed an in-person interview on socio-demographic, reproductive, medical and lifestyle characteristics and personal attributes. Serum 25(OH)D concentrations were quantified by liquid chromatography-tandem MS. Multivariable least squares regression was used to build models that predict 25(OH)D concentrations from interview responses. We assessed high-order effects, performed sensitivity analysis using the lasso method and conducted cross-validation of the prediction models. Prediction models were built for users and non-users of vitamin D supplements separately. Among users, alcohol intake, outdoor time, sun protection, dose of supplement use, menopausal status and recent vacation were predictive of 25(OH)D concentrations. Among non-users, BMI, sun sensitivity, season and recent vacation were predictive of 25(OH)D concentrations. In cross-validation, 46-47 % of the variation in 25(OH)D concentrations were explained by these predictors. In the absence of 25(OH)D measures, our study supports that predicted 25(OH)D scores may be used to assign exposure in epidemiological studies that examine vitamin D exposure.

Risk Factors for the Development of Cephalic Arch Stenosis

Purpose

The creation of a vascular access is necessary in hemodialysis patients, including those with marginal vessels. Upper arm fistulae are attractive due to the ease of creation and of achieving high access flow rates. Cephalic arch stenosis (CAS) can lead to failure of upper arm fistulae and is increasingly identified. We hypothesized that CAS is promoted by high blood flow rates, brachiocephalic fistulae, and an angle of cephalic vein insertion approaching 90 degrees.

Methods

All patients requiring a fistulogram between January 2004 and May 2006 had surveillance fluoroscopy of the central veins. Demographic, clinical and laboratory parameters were collected and the angle of the cephalic vein insertion measured by 3 blinded independent observers.

Results

Fifty-eight patients had fistulograms and CAS was detected in 18 subjects. Significant differences between the CAS and non-CAS groups were brachiocephalic fistula site (p=0.046), access flow (mL/min) (p=0.012), and absence of diabetes (p=0.03). Univariate predictors of CAS include access flow (per 100 mL/min) (p=0.042), platelet count (p=0.031) and calcium-phosphate product (p=0.026). The relationship of brachiocephalic site and CAS was confounded by access flow [(per 100 mL/min)*brachiocephalic fistula site (p=0.016)] and fistula age [brachiocephalic fistula site*fistula age (p=0.017)]. In multivariate analysis, renovascular disease, calcium-phosphate product, platelet count and access flow (per 100 mL/min)*brachiocephalic fistula predicted CAS (p<0.001, Negelkerke's R-Square= 0.55). The angle of insertion of the cephalic vein was not predictive for CAS.

Conclusions

CAS may be a long-term consequence of high blood flow rates. The interaction of access flow and brachiocephalic fistula supports the hypothesis that high flow through a brachiocephalic fistula promotes CAS. The multiple factors influencing cephalic arch remodeling require further research.

High Vitamin D Levels May Downregulate Inflammation in Patients with Behçet's Disease

Vitamin D plays a significant role in the immune system modulation and may confer a protective role in autoimmune diseases. We conducted a case-control study to compare 25(OH)D levels in patients with BD who were managed at a regional rheumatology programme in the midwest region of Ireland compared to matched controls. Healthy controls were selected from the Irish health system and matched in 1 : 5 ratio for age, sex, and the month of the year. 25(OH)D levels <20 nmol/L were classified as deficient while levels between 20 and 40 nmol/L were classified as insufficient. Differences between groups were assessed using Mann-Whitney test and associations between cases and controls were expressed as odds ratios and 95% confidence intervals. Nineteen patients with BD were compared with 95 controls matched by age, sex, and month of blood draw. 25(OH)D levels were significantly higher in patients in BD than in matched controls (median values: 45 nmol/L versus 22 nmol/L, p < 0.005) and tended to be lower in patients with active disease than in those without (median values: 35 nmol/L (IQR: 22.75-47.25 nm/L) versus 50 nmol/L (IQR: 35-67 nmol/L), p = 0.11). Compared to controls, patients with BD were significantly less likely to have 25(OH)D deficiency or insufficiency (OR: 0.09, 95% CI: 0.03-0.28, p < 0.001). Our findings suggest a possible role for 25(OH)D in modifying the inflammatory response in BD and uncover a potential opportunity to assess whether correction of Vit D deficiency confers protective benefits.

Assessment of vitamin D status – a changing landscape

In recent years it has been shown that vitamin D deficiency is associated with an increased incidence as well as the progression of a broad range of diseases including osteoporosis, rickets, cardiovascular disease, autoimmune disease, multiple sclerosis and cancer. Consequently, requests for the assessment of vitamin D status have increased dramatically. Despite significant progress in the analysis of vitamin D metabolites and an expansion of our pathophysiological knowledge of vitamin D, the assessment of vitamin D status remains a challenging and partially unresolved issue. Current guidelines from scientific bodies recommend the measurement of 25-hydroxy vitamin D (25-OHD) in blood as the preferred test. However, growing evidence indicates significant limitations of this test, including analytical aspects and interpretation of results. In addition, the relationships between 25-OHD and various clinical indices, such as bone mineral density and fracture risk, are rather weak and not consistent across races. Recent studies have systematically investigated new markers of vitamin D status including the vitamin D metabolite ratio (VMR) (ratio between 25-OHD and 24,25-dihydroxy vitamin D), bioavailable 25-OHD [25-OHD not bound to vitamin D binding protein (DBP)], and free 25-OHD [circulating 25-OHD bound to neither DBP nor albumin (ALB)]. These parameters may potentially change how we will assess vitamin D status in the future. Although these new biomarkers have expanded our knowledge about vitamin D metabolism, a range of unresolved issues regarding their measurement and the interpretation of results prevent their use in daily practice. It can be expected that some of these issues will be overcome in the near future so that they may be considered for routine use (at least in specialized centers). In addition, genetic studies have revealed several polymorphisms in key proteins of vitamin D metabolism that affect the circulating concentrations of vitamin D metabolites. The affected proteins include DBP, 7-dehydrocholesterol synthase and the vitamin D receptor (VDR). Here we aim to review existing knowledge regarding the biochemistry, physiology and measurement of vitamin D. We will also provide an overview of current and emerging biomarkers for the assessment of vitamin D status, with particular attention methodological aspects and their usefulness in clinical practice.

Polymeric nanospheres for topical delivery of vitamin D3

This study investigates the potential application of polymeric nanospheres (known as TyroSpheres) as a formulation carrier for topical delivery of cholecalciferol (i.e., Vitamin D3, VD3) with the goal to improve the skin delivery and stability of VD3. High drug loading and binding efficiencies were obtained for VD3 when loaded in TyroSpheres. VD3 was released from TyroSpheres in a sustained manner and was delivered across the stratum corneum, which occurred independent of the initial drug loading. An ex vivo skin distribution study showed that TyroSphere formulations delivered 3-10μg of active into the epidermis which was significantly higher than that delivered from Transcutol^® (the control vehicle). In addition, an in vitro cytotoxicity assay using keratinocytes confirmed that VD3 encapsulation in the nanoparticles did not alter the drug activity. Photodegradation of VD3 followed zero-order kinetics. TyroSpheres were able to protect the active against hydrolysis and photodegradation, significantly enhancing the stability of VD3 in the topical formulation.

Low vitamin D-modulated calcium-regulating proteins in psoriasis vulgaris plaques: S100A7 overexpression depends on joint involvement

Psoriasis is an inflammatory skin disease with or without joint involvement. In this disease, the thickened epidermis and impaired barrier are associated with altered calcium gradients. Calcium and vitamin D are known to play important roles in keratinocyte differentiation and bone metabolism. Intracellular calcium is regulated by calcium-sensing receptor (CASR), calcium release-activated calcium modulator (ORAI) and stromal interaction molecule (STIM). Other proteins modulated by vitamin D play important roles in calcium regulation e.g., calbindin 1 (CALB1) and transient receptor potential cation channel 6 (TRPV6). In this study, we aimed to investigate the expression of calcium-regulating proteins in the plaques of patients with psoriasis vulgaris with or without joint inflammation. We confirmed low calcium levels, keratinocyte hyperproliferation and an altered epidermal barrier. The CASR, ORAI1, ORAI3, STIM1, CALB1 and TRPV6 mRNA, as well as the sterol 27-hydroxylase (CYP27A1), 25-hydroxyvitamin D3 1-α-hydroxylase (CYP27B1) and 1,25-dihydroxyvitamin D3 24-hydroxylase (CYP24A1) protein levels were low in the plaques of patients with psoriasis. We demonstrated S100 calcium-binding protein A7 (S100A7) overexpression in the plaques of patients with psoriasis vulgaris with joint inflammation, compared with those without joint involvement. We suggest an altered capacity to regulate the intracellular Ca2+ concentration ([Ca2+]i), characterized by a reduced expression of CASR, ORAI1, ORAI3, STIM1, CALB1 and TRPV6 associated with diminished levels of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], which may be associated with an altered balance between keratinocyte proliferation and differentiation in the psoriatic epidermis. Additionally, differences in S100A7 expression depend on the presence of joint involvement.

Impact of vitamin D receptor polymorphisms in centenarians

Vitamin D is a seco-sterol produced endogenously in the skin or obtained from certain foods. It exerts its action through binding to intracellular vitamin D receptor (VDR). Lately, the role of vitamin D has been revised regarding its potential advantage on delaying the process of aging. The aim of this study was to assess the contribution of VDR gene polymorphisms in healthy aging and longevity. We evaluated the frequency of four polymorphisms of the VDR gene (FokI, BsmI, ApaI, and TaqI) in centenarians (102 subjects, mean age: 102.3 ± 0.3 years), compared to septuagenarians (163 subjects, mean age: 73.0 ± 0.6 years) and we analyzed a variety of pathophysiologically relevant functions in centenarians. BsmI and ApaI provided a significant association with longevity: there was a highly significant difference in the frequency of BsmI genotypes (p = 0.037), ApaI genotypes (p = 0.022), and ApaI alleles (p = 0.050) in centenarians versus septuagenarians. Furthermore, we found a significant correlation of all the VDR gene polymorphisms in centenarians with some measured variables such as hand grip strength, body mass index, blood pressure, HDL cholesterol, and mini-mental state examination. We also found a correlation with the prevalence of medical history of hypertension, acute myocardial infarction, angina, venous insufficiency, dementia, chronic obstructive pulmonary disease, and arthrosis. In conclusion, this study proposes a new scenario in which the variability of the VDR gene is relevant in the aging process and emphasizes the role of VDR genetic background in determining healthy aging.

Phototherapy and vitamin D

The skin is the site for the photosynthesis of vitamin D and is a target tissue for the active metabolite of vitamin D. An increasing body of evidence indicates that vitamin D produced during phototherapy may be responsible for the positive effects observed during treatment of some skin diseases. Topical or oral application of vitamin D derivatives are used alone or with phototherapy. This paper reviews what is known about the use of phototherapy to enhance vitamin D levels, the use of vitamin D analogues with phototherapy, the efficacy of combination therapies, and controversies regarding some of the outcomes. Vitamin D can play a beneficial role in treating psoriasis, even though the exact role of vitamin D in the pathogenesis and severity of psoriasis remains unclear. The role of vitamin D in vitiligo, atopic dermatitis, polymorphic light eruption, and mycosis fungoides must be further investigated.

Efficacy of narrowband ultraviolet B phototherapy and levels of serum vitamin D3 in psoriasis: A prospective study

INTRODUCTION

Narrowband ultraviolet B phototherapy (NBUVB) is safe and effective treatment for psoriasis. Vitamin D plays an important role in pathogenesis of psoriasis. It is known that psoriasis patients have low serum 25(OH)D levels, which increase after NBUVB. We assessed serum 25(OH)D levels, its correlation with Psoriasis Area and Severity Index (PASI), and the effect of NBUVB on 25(OH)D levels among Indian psoriasis patients.

MATERIALS AND METHODS

A prospective study comprising 30 adults with psoriasis with no major comorbidities (PASI > 10 and off-therapy >4 weeks) was conducted. PASI was estimated at baseline among patients and repeated after receiving 12 weeks of NBUVB therapy. Thirty age and gender-matched healthy controls were recruited to compare 25(OH)D levels at baseline and at 12 weeks. Patient demographic parameters, treatment dose, duration, side effects, and its impact on 25(OH)D levels and PASI were serially evaluated.

RESULTS

A total of 30 patients presenting with psoriasis and 30 healthy controls were enrolled in the study. Mean baseline PASI (M: F =19:11) among patients with mean age 36.8 (±7.7) years was 20.5 (±6.3) and all patients were either 25(OH)D deficient (n = 14) or insufficient (n = 16). Their baseline 25(OH)D levels were significantly lower than controls (25.93 nmol/L vs 47.54 nmol/L; P < 0.001). After NBUVB therapy (average cumulative dose 20.76 ± 7.1 J/cm(2); average treatment sessions 32.57 ± 1.9), there was a significant improvement in PASI as well as 25(OH)D (P < 0.05). There was no correlation between the mean improvement in PASI and 25(OH)D after 12 weeks of therapy. Twelve (40%) patients had therapy-related side effects [pruritus (n = 8), erythema (n = 4)], none had major side effects.

CONCLUSION

Improvement in PASI and serum 25(OH)D levels after NBUVB in psoriasis is significant but poorly correlated with each other. Vitamin D may not be the lone mediator of the therapeutic effects of NBUVB on psoriasis.

Microarray Analysis of Differentially-Expressed Genes Encoding CYP450 and Phase II Drug Metabolizing Enzymes in Psoriasis and Melanoma

Cytochrome P450 drug metabolizing enzymes are implicated in personalized medicine for two main reasons. First, inter-individual variability in CYP3A4 expression is a confounding factor during cancer treatment. Second, inhibition or induction of CYP3A4 can trigger adverse drug–drug interactions. However, inflammation can downregulate CYP3A4 and other drug metabolizing enzymes and lead to altered metabolism of drugs and essential vitamins and lipids. Little is known about effects of inflammation on expression of CYP450 genes controlling drug metabolism in the skin. Therefore, we analyzed seven published microarray datasets, and identified differentially-expressed genes in two inflammatory skin diseases (melanoma and psoriasis). We observed opposite patterns of expression of genes regulating metabolism of specific vitamins and lipids in psoriasis and melanoma samples. Thus, genes controlling the turnover of vitamin D (CYP27B1, CYP24A1), vitamin A (ALDH1A3, AKR1B10), and cholesterol (CYP7B1), were up-regulated in psoriasis, whereas melanomas showed downregulation of genes regulating turnover of vitamin A (AKR1C3), and cholesterol (CYP39A1). Genes controlling abnormal keratinocyte differentiation and epidermal barrier function (CYP4F22, SULT2B1) were up-regulated in psoriasis. The up-regulated CYP24A1, CYP4F22, SULT2B1, and CYP7B1 genes are potential drug targets in psoriatic skin. Both disease samples showed diminished drug metabolizing capacity due to downregulation of the CYP1B1 and CYP3A5 genes. However, melanomas showed greater loss of drug metabolizing capacity due to downregulation of the CYP3A4 gene.

Vitamin D deficiency at melanoma diagnosis is associated with higher Breslow thickness

BACKGROUND

Epidemiological evidence shows that people with thicker, or higher stage, melanomas have lower vitamin D status compared to those with thinner tumours. Evidence from experimental studies is inconsistent, but some suggest that administration of vitamin D metabolites can decrease tumour aggressiveness.

OBJECTIVES

Determine the relationship between vitamin D status at diagnosis and melanoma thickness (as an indicator of prognosis), in a subtropical setting with high melanoma incidence.

METHODS

We recruited 100 melanoma patients in Brisbane, Australia within days of their diagnosis. Data on factors previously associated with melanoma risk or prognosis were collected by questionnaire and physical examination. Serum for 25-hydroxyvitamin D3 [25(OH)D] levels was collected prior to wider excision biopsy; histological indicators of prognosis were obtained from pathology reports. We used multivariable logistic regression models to analyse the association between Breslow thickness (≥0.75 mm compared to <0.75 mm), Clark level (2-5 compared to 1) and presence of mitoses, and vitamin D status.

RESULTS

Serum 25(OH)D <50 nmol/L (versus ≥50 nmol/L) was associated with a nearly four-fold increase in risk of having a thicker tumour (Adjusted OR = 3.82, 95% CI: 1.03, 14.14; p = 0.04, adjusted for age, sex, skin phototype, body mass index and season at diagnosis). There was no significant association with Clark level or presence of mitosis. Serum 25(OH)D levels in the highest quartile (≥69.8 nmol/L) were not associated with a more favourable prognosis.

CONCLUSIONS

Vitamin D deficiency at the time of melanoma diagnosis is associated with thicker tumours that are likely to have a poorer prognosis. Ensuring vitamin D levels of 50 nmol/L or higher in this population could potentially result in 18% of melanomas having Breslow thickness of <0.75 mm rather than ≥0.75 mm.

The role of telomeres and vitamin D in cellular aging and age-related diseases

Aging is a complex biological process characterized by a progressive decline of organ functions leading to an increased risk of age-associated diseases and death. Decades of intensive research have identified a range of molecular and biochemical pathways contributing to aging. However, many aspects regarding the regulation and interplay of these pathways are insufficiently understood. Telomere dysfunction and genomic instability appear to be of critical importance for aging at a cellular level. For example, age-related diseases and premature aging syndromes are frequently associated with telomere shortening. Telomeres are repetitive nucleotide sequences that together with the associated sheltrin complex protect the ends of chromosomes and maintain genomic stability. Recent studies suggest that micronutrients, such as vitamin D, folate and vitamin B12, are involved in telomere biology and cellular aging. In particular, vitamin D is important for a range of vital cellular processes including cellular differentiation, proliferation and apoptosis. As a result of the multiple functions of vitamin D it has been speculated that vitamin D might play a role in telomere biology and genomic stability. Here we review existing knowledge about the link between telomere biology and cellular aging with a focus on the role of vitamin D. We searched the literature up to November 2014 for human studies, animal models and in vitro experiments that addressed this topic.

The diffuse component of erythemal ultraviolet radiation

The diffuse (Dif) component of ultraviolet radiation (UVR) plays an important role in the daily exposure of humans to solar radiation.

Prenatal factors associated with the neonatal line thickness in human deciduous incisors

The neonatal line (NNL) is used to distinguish developmental events observed in enamel which occurred before and after birth. However, there are few studies reporting relationship between the characteristics of the NNL and factors affecting prenatal conditions. The aim of the study was to determine prenatal factors that may influence the NNL thickness in human deciduous teeth. The material consisted of longitudinal ground sections of 60 modern human deciduous incisors obtained from full-term healthy children with reported birth histories and prenatal factors. All teeth were sectioned in the labio-lingual plane using diamond blade (Buechler IsoMet 1000). Final specimens were observed using scanning electron microscopy at magnifications 320×. For each tooth, linear measurements of the NNL thickness were taken on its labial surface at the three levels from the cemento-enamel junction. The difference in the neonatal line thickness between tooth types and between males and females was statistically significant. A multiple regression analyses confirmed influence of two variables on the NNL thickness standardised on tooth type and the children's sex (z-score values). These variables are the taking of an antispasmodic medicine by the mother during pregnancy and the season of the child's birth. These two variables together explain nearly 17% of the variability of the NNL. Children of mothers taking a spasmolytic medicine during pregnancy were characterised by a thinner NNL compared with children whose mothers did not take such medication. Children born in summer and spring had a thinner NNL than children born in winter. These results indicate that the prenatal environment significantly contributes to the thickness of the NNL influencing the pace of reaching the post-delivery homeostasis by the newborn's organism.

Influence of external, intrinsic and individual behaviour variables on serum 25(OH)D in a German survey

The objective of the present study was to identify external, intrinsic or behavioural factors that significantly influenced serum 25-hydroxyvitamin D (25(OH)D) concentrations in a German survey. Data from 3061 participants in the Cooperative Health Research in the Region of Augsburg, Germany (KORA) F4 survey were used to relate potential determinants to measured mean serum 25(OH)D concentrations using multivariable regression models. The factors significantly associated with hypovitaminosis D (defined as 25(OH)D<25 nmolL(-1)) were season (winter, spring and autumn), urban environment and high body mass index. In contrast, times spent in sunny regions, hours per day spent outdoors in the summer as well as additional oral intake were associated with higher 25(OH)D concentrations. These results suggest that mainly ambient UV exposure but also individual behaviour are the most important determinants for personal 25(OH)D concentrations. The analyses further showed that in winter 43% of subjects were vitamin D deficient and 42% insufficient. Even in summer over half the population has insufficient vitamin D status with 8% deficient and 47% insufficient. Therefore measures to mitigate widespread vitamin D insufficiency such as regular short-term sun exposure and/or improved dietary intake/supplementation recommendations by public health bodies need to be considered.

Analysis of FokI polymorphism of vitamin D receptor gene in intervertebral disc degeneration

AIM

We have hypothesized a possible relationship between disc degeneration (DD) and VDR FokI/T2C polymorphism.

METHODS

A case-control study was performed comprising 121 Brazilian patients with confirmed DD by nuclear magnetic resonance and a control group consisting of 131 healthy patients without a history of disc cysts of the lumbar spine. Detection of VDR FokI/T2C polymorphism was performed using restriction fragment length polymorphism-polymerase chain reaction. The chi-square test was used to compare allele and genotype frequencies between groups, and a p-value of <0.05 was considered statistically significant.

RESULTS

The results disclosed statistical difference between allele distribution among cases and controls (p=0.025, odds ratio=1.58, confidence interval=1.07-2.32) considering VDR FokI/T2C polymorphism.

CONCLUSION

The results showed a positive association between VDR FokI/T2C polymorphism and DD in Brazilian patients tested.

Determination of a safe and effective ultraviolet B radiant dose in budgerigars (Melopsittacus undulatus): a pilot study

The object of this study was to establish a minimum dose of ultraviolet B (UVB) radiation capable of producing an erythemal reaction in budgerigars (Melopsittacus undulatus), to determine a threshold dose of UVB for vitamin D photoconversion, and to investigate the use of safer UVB wavelengths. In each of 5 experiments of this study, 20 birds were divided into a control group (n = 10) and a UVB irradiated group (n = 10). Light sources that provide broadband UVB wavelengths (280-315 nm) and narrowband UVB (310-320 nm) were used. Varied doses of UVB radiation were administered to budgerigars by altering exposure time and irradiance. Safety was determined by observing body weight and incidence of photokeratitis and photodermatitis. Efficacy was evaluated by measuring changes in serum 25-hydroxycholecalciferol levels. Serum corticosterone was measured in 1 experiment to monitor stress levels. The results demonstrated that exposure to 180 mJ/cm2 broadband UVB induced vitamin D photoconversion, decreased body weights, and increased serum corticosterone levels. At these wavelengths, UVB-induced lesions were observed. A broadband UVB of 150 to 300 mJ/cm2 was determined as the minimum erythema dose, and the threshold dose for vitamin D photoconversion was calculated to be in the range of 113-225 mJ/cm2. No erythemal lesions or vitamin D photoconversion took place after exposure to up to 1730 mJ/cm2 narrowband UVB radiation. A minimum erythema dose and a threshold dose for vitamin D conversion need to be determined for each species if phototherapy is to be considered as a safe and effective therapeutic or husbandry tool.

Two neglected biologic risk factors in bone grafting and implantology: high low-density lipoprotein cholesterol and low serum vitamin D

Following a failure of a bone graft or an implant placement, the hypothesis of a biological abnormality is rarely considered as a possible cause. A systematic search of peer-reviewed literature for dyslipidemia or vitamin D deficiency may explain this lack of consideration. Excess low-density lipoprotein cholesterol (dyslipidemia) is responsible for a slower bone metabolism or lower dental implant osseointegration. In addition, vitamin D is a key factor for linking innate and adaptive immunity. Both of these factors are compromised under the conditions of vitamin D deficiency. Therefore, vitamin D deficiency slows implant osseointegration and increases the risk of graft infection. Vitamin D is also involved in immune function and therefore allergic reactions.

Determination of vitamin D and its metabolites

The demand for analysis of 25-hydroxyvitamin D has increased dramatically throughout the world over the past decade. As a consequence, a number of new automated assays have been introduced for 25-hydroxyvitamin D measurement. Automated assays have shown variable ability to meet the technical challenges associated with 25-hydroxyvitamin D measurement. Assays are able to meet performance goals for precision at high concentrations but fail to do so at low concentrations of 25-hydroxyvitamin D. The overall accuracy of automated methods has improved over recent years and generally shows good overall agreement with reference methods; however, discrepancies persist for individual samples. Liquid chromatography-tandem mass spectrometry is used by some routine laboratories for 25-hydroxyvitamin D analysis but its widespread use is hampered by limited sample throughput. 1,25-Dihydroxyvitamin D is an important analyte in specific clinical situations, which remains in the hands of specialised laboratories using manual analytical methods.

Estimation of daily ultraviolet radiation in Beijing using a semiempirical method

This study proposes a semiempirical method to reconstruct daily ultraviolet (UV) radiation from global solar (G) radiation measurements using a radiative transfer model. The attenuation ratio and cloud modification factors are calculated based on measured and simulated data under cloudless-sky conditions. A reconstruction method of UV radiation is established using cloud modification factors; based on comparisons among reconstructions and measurements, the reconstruction model is demonstrated to offer high resolution. The bias errors for daily measured and reconstructed UV radiation are maintained within ±20%, the mean absolute bias error (mabe) is 7.7% and the root mean square error (rmse) is 9.7%. Furthermore, the model performance and transferability were tested by comparison with a simple empirical model in Beijing, Eerduosi and Hailun. A comparison of the measured and estimated UV values for the two methods in the aforementioned three locations revealed that smaller mabe and rmse were observed in our method, with both of these values in the three locations being less than 14%. Thus, a better applicability and transferability has been confirmed. The results and analysis should contribute to improving the knowledge about actual UV climate characteristics.

The current state of play of rodent models to study the role of vitamin D in UV-induced immunomodulation

Ultraviolet radiation (UVR) from sunlight is immunomodulatory and the main source of vitamin D for humans. Vitamin D can also regulate adaptive immunity, through mechanisms that involve the induction or activation of regulatory T cells. Similar mechanisms have also been proposed for the induction of regulatory T cells after skin exposure to UVR. Here we discuss the converging and diverging immunoregulatory pathways of UVR and vitamin D, including the molecular pathways for regulatory T cell induction, non-genomic pathways regulated by vitamin D, antimicrobial peptides, skin integrity and potential interactions between vitamin D and other UVR-induced mediators. We then discuss possible in vivo approaches that could be used to demonstrate a direct (or otherwise) role for vitamin D in mediating the immunosuppressive effects of UVR such as the use of dietary vitamin D restriction to induce vitamin D deficiency, gene knockout mice or drugs to block enzymes of vitamin D metabolism. We end with discussion of the epigenetic effects of vitamin D and UVR for immunosuppression.

Patients with polymorphic light eruption have decreased serum levels of 25-hydroxyvitamin-D3 that increase upon 311 nm UVB photohardening

BACKGROUND

Polymorphic light eruption (PLE) is a very common condition whose pathogenesis may involve immunological abnormalities. Vitamin D sufficiency is thought to be important for normal immune function.

OBJECTIVE

To determine whether PLE patients are vitamin D deficient and to study how photohardening with 311 nm UVB affects the vitamin D status of PLE patients.

METHODS

The vitamin D status of 23 PLE patients (21 females and 2 males; age range, 18-55 years) was analysed at four different time points (early spring, late spring, summer, and winter) by measuring 25-hydroxyvitamin-D(3) (25(OH)D) serum levels through a standardised immunoassay. Fifteen of those patients received 311 nm UVB in early spring for prevention of PLE symptoms. 25(OH)D levels of the PLE patients were compared to that of 23 sex-, age-, and body-mass-index post hoc-matched control subjects.

RESULTS

PLE patients had low levels of 25(OH)D throughout the year compared to that of the control subjects. At baseline in early spring, the mean ± SD 25(OH)D level was 14.9 ± 3.0 ng ml(-1) in the PLE patients that would later receive 311 nm UVB and 14.4 ± 2.4 ng ml(-1) in the patients not receiving 311 nm UVB. Successful prophylactic treatment with 311 nm UVB significantly increased 25(OH)D levels to a mean of 21.0 ± 3.4 ng ml(-1) (p < 0.001; ANOVA, Tukey's test). Heading into summer, the 25(OH)D levels in treated patients decreased again, reaching their lowest levels in winter. In contrast, the 25(OH)D levels of untreated PLE patients stayed in the low range in early and late spring but increased by trend towards summer, reaching similar levels to that of the PLE patients who had received 311 nm UVB (17.1 ± 2.3 vs. 17.3 ± 6.0 ng ml(-1)). Like the treated PLE patients, 25(OH)D levels of untreated patients significantly decreased in winter to comparable levels (12.2 ± 1.9 vs. 13.8 ± 1.8 ng ml(-1)). Taken together, the 25(OH)D levels of PLE patients were significantly lower at all time points than that observed in the matched control population (34.4 ± 12.5 ng ml(-1)) (p < 0.000003).

CONCLUSIONS

PLE patients have low 25(OH)D serum levels. 311 nm UVB phototherapy that prevented PLE symptoms increased those levels. Thus, we speculate that boosting levels of vitamin D may be important in ameliorating PLE.

Intradermal application of vitamin D3 increases migration of CD14+ dermal dendritic cells and promotes the development of Foxp3+ regulatory T cells

The active form of vitamin D3 (VitD) is a potent immunosuppressive drug. Its effects are mediated in part through dendritic cells (DCs) that promote the development of regulatory T cells (Tregs). However, it remains elusive how VitD would influence the different human skin DC subsets, e.g., CD1a(+)/langerin(+) Langerhans cells, CD14(+) DDCs and CD1a(+) DDCs upon administration through the skin route in their natural environment. We addressed this issue by intradermal (ID) administration of VitD in a human skin explant system that closely resembles physiological conditions. ID injection of VitD selectively enhanced the migration of CD14(+) DDCs, a subset known for the induction of tolerance. Moreover, ID injection of VitD repressed the LPS-induced T cell stimulatory capacity of migrating DCs. These migrating DCs collectively induced T cells with suppressive activity and abolished IFN-γ productivity. Those induced T cells were characterized by the expression of Foxp3. Thus, we report the novel finding that ID injection of VitD not only modifies skin DC migration, but also programs these DCs in their natural milieu to promote the development of Foxp3(+) Tregs.

Environmental risk factors for multiple sclerosis: a review with a focus on molecular mechanisms

Multiple sclerosis (MS) is a chronic disabling disease of the central nervous system commonly affecting young adults. Pathologically, there are patches of inflammation (plaques) with demyelination of axons and oligodendrocyte loss. There is a global latitude gradient in MS prevalence, and incidence of MS is increasing (particularly in females). These changes suggest a major role for environmental factors in causation of disease. We have reviewed the evidence and potential mechanisms of action for three exposures: vitamin D, Epstein Barr virus and cigarette smoking. Recent advances supporting gene-environment interactions are reviewed. Further research is needed to establish mechanisms of causality in humans and to explore preventative strategies.

Human skin pigmentation, migration and disease susceptibility

Human skin pigmentation evolved as a compromise between the conflicting physiological demands of protection against the deleterious effects of ultraviolet radiation (UVR) and photosynthesis of UVB-dependent vitamin D(3). Living under high UVR near the equator, ancestral Homo sapiens had skin rich in protective eumelanin. Dispersals outside of the tropics were associated with positive selection for depigmentation to maximize cutaneous biosynthesis of pre-vitamin D(3) under low and highly seasonal UVB conditions. In recent centuries, migrations and high-speed transportation have brought many people into UVR regimes different from those experienced by their ancestors and, accordingly, exposed them to new disease risks. These have been increased by urbanization and changes in diet and lifestyle. Three examples-nutritional rickets, multiple sclerosis (MS) and cutaneous malignant melanoma (CMM)-are chosen to illustrate the serious health effects of mismatches between skin pigmentation and UVR. The aetiology of MS in particular provides insight into complex and contingent interactions of genetic and environmental factors necessary to trigger lethal disease states. Low UVB levels and vitamin D deficiencies produced by changes in location and lifestyle pose some of the most serious disease risks of the twenty-first century.

Analysis of vitamin D receptor gene (VDR) polymorphisms in Turner syndrome patients

Individuals with Turner syndrome (TS) have increased risk for autoimmune diseases, especially thyroid abnormalities. The function of the vitamin D receptor (VDR) gene is influenced by several genetic polymorphisms which are associated with a susceptibility to a range of autoimmune diseases. Thus, we have hypothesized a possible relationship between thyroid abnormalities and VDR polymorphisms (ApaI/G1025-49T, TaqI/T1056C, FokI/T2C and BsmI G1024 + 283A) in TS patients. A case-control study was performed comprising 101 Brazilian women with TS and a control group consisting of 133 healthy fertile women without a history of autoimmune diseases. In TS group, 21.8% had Hashimoto's thyroiditis. Detection of VDR polymorphisms was performed using TaqMan system by real-time PCR. The χ(2) was used to compare allele and genotype frequencies between groups. Combined genotypes of VDR gene polymorphisms were assessed by the haplotype analysis. A p value <0.05 was considered statistically significant. Relatively similar VDR polymorphisms genotype and allelic frequencies in cases and controls were found, even when only considering the patients with thyroid abnormalities. Haplotype analysis showed that none of the VDR haplotypes were associated to thyroid diseases in TS patients. In conclusion, the results showed no association between VDR gene polymorphisms and thyroid abnormalities in Brazilian TS patients tested.

Serum 25-hydroxyvitamin-D responses to multiple UV exposures from solaria: inferences for exposure to sunlight

We investigate the relationship between blood serum 25-hydroxyvitamin D (25(OH)D) and UV exposure from two artificial sources. We then use the results to test the validity of the action spectrum for vitamin D production, and to infer the production from summer and winter sunlight. The results are based on a two-arm randomised clinical trial of biweekly UV exposure for 12 weeks using two different types of dermatological booths: one emitting primarily UV-A radiation, and the other emitting primarily UV-B radiation (booth A and booth B respectively). In terms of the vitamin D production per unit erythema, one of the booths mimics summer noon sunlight, while the other mimics winter noon sunlight. Blood samples were taken before and after the exposures. For all participants, the phototherapy booth treatments arrested the usual wintertime decline in 25(OH)D, and for most the treatments from either booth resulted in significant increases. The increases were highly non-linear and there was a high degree of variability in 25(OH)D and its response to UV from person to person. By the end of the 12 week period, the mean increase was >30 nmol l(-1) from a cumulative exposure of 17 SED from the UV-A booth, and twice that for the UV-B booth for which the cumulative exposure was 268 SED. Assuming a logarithmic relationship between UV and vitamin D, the results for the two booths show no obvious inconsistency in the action spectrum for pre-vitamin D production. However, further measurements with similar exposures from each booth are required to confirm its validity. A model was developed to describe the increases in serum 25(OH)D resulting from the UV exposures, which differed markedly between the two booths. The deduced initial rate of increase of 25(OH)D was approximately 5 nmol l(-1) per SED. From the large increases in 25(OH)D from each booth, along with knowledge of the spectral distribution of sunlight and assuming the currently-accepted action spectrum for photo-conversion to pre-vitamin D, we infer that the production of 25(OH)D from sunlight should be possible throughout the year, although in winter the exposures necessary to maintain optimal levels of 25(OH)D would be impractically long. This finding is at variance with the commonly-held view that no vitamin D is produced at mid-latitudes in the winter. Further work is needed to resolve that inconsistency.

Photoisomerization of alfa calcidol by a sensitized quantum chain reaction

The production of vitamin D3 is a pharmaceutically relevant process, producing high added-value products. Precursors are extracts from vegetal origin but bearing mainly an E geometry in the 5,6 double bond. The synthesis of vitamin D3 (5-E-α-calcidol) with the correct Z stereochemistry in the 5,6 double bond from the E isomer using anthracene and triethylamine (TEA) as the sensitizer system was studied from the kinetic and mechanistic point of view. The sensitized isomerization of E-calcidol by irradiation of anthracene takes place only in deoxygenated solution and yields the Z isomer in ca 5% yield in the photostationary state. When TEA is added to the system, the E-Z reaction is not inhibited by oxygen any more, the quantum yield of photoisomerization to the Z isomer grows linearly with the concentration of E-calcidol, while conversions higher than 95% to the Z isomer are reached in the photostationary state and E-Z quantum yields as high as 45 at [E-calcidol] = 25 mM are reached. If TEA is replaced by 1,4-diazabicyclo[2.2.2]octane, the reaction rate drops to one-third at the same amine concentration. The observations can be explained by a quantum chain reaction mechanism. The high conversion achieved eliminates the need of isomer separation.

Vitamin D status in psoriasis patients during different treatments with phototherapy

BACKGROUND

Phototherapy (broadband UVB (BUVB), narrowband UVB (NBUVB) and heliotherapy) is commonly used treatment modalities for widespread psoriasis. Vitamin D3, cholecalciferol, is produced in the epidermis by ultraviolet radiation (290-315 nm) of 7-dehydrocholesterol. 25-hydroxyvitamin D [25(OH)D], and 1,25-dihydroxyvitamin D [1,25(OH)(2)D] are the major circulating metabolites. Sun exposure is the strongest factor influencing 25(OH)D. The similar wavelength spectrum of UVB responsible for D vitamin synthesis (BUVB, 280-315 nm) has been successfully used for years to treat psoriasis.

PURPOSE

The aim was: (1) To increase the knowledge about the effects of phototherapy on vitamin D production during treatment of psoriasis. (2) To examine if there were differences between the effect of BUVB, NBUVB and heliotherapy on vitamin D synthesis in psoriasis patients.

METHODS

Serum concentrations of 25(OH)D, 1,25(OH)(2)D, PTH, calcium and creatinine, measured before and after phototherapy in white Caucasian patients with moderate to severe active plaque psoriasis, were aggregated from three studies.

RESULTS

Psoriasis improved in all patients, with a reduction in PASI ((Psoriasis Area and Severity Index) score of about 75% on all regimes. Serum 25(OH)D increased and PTH decreased after the phototherapy. The increase in 25(OH)D was higher in the BUVB treated patients compared with NBUVB. There was no correlation between the dose of UVB and the increase of 25(OH)D.

CONCLUSION

UVB and heliotherapy improved the psoriasis score, increased the serum 25(OH)D levels and reduced the serum PTH concentrations. Vitamin D production in psoriasis patients increased less with NBUVB than with BUVB phototherapy.

20,23-dihydroxyvitamin D3, novel P450scc product, stimulates differentiation and inhibits proliferation and NF-kappaB activity in human keratinocytes

We have examined effects of the 20,23-dihydroxyvitamin D3 (20,23(OH)2D3), on differentiation and proliferation of human keratinocytes and the anti-inflammatory potential of 20,23(OH)2D3 from its action on nuclear factor-kappaB (NF-kappaB). 20,23(OH)2D3 inhibited growth of keratinocytes with a potency comparable to that for 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). Cell cycle analysis showed that this inhibition was associated with G1/G0 and G2/M arrests. 20,23(OH)2D3 stimulated production of involucrin mRNA and inhibited production of cytokeratin 14 mRNA in a manner similar to that seen for 1,25(OH)2D3. Flow cytometry showed that these effects were accompanied by increased involucrin protein expression, and an increase in the cell size and granularity. Silencing of the vitamin D receptor (VDR) by corresponding siRNA abolished the stimulatory effect on involucrin gene expression demonstrating an involvement of VDR in 20,23(OH)2D3 action. This mode of action was further substantiated by stimulation of CYP24 gene expression and stimulation of the CYP24 promoter-driven reporter gene activity. 20,23(OH)2D3 displayed several fold lower potency for induction of CYP24 gene expression than 1,25(OH)2D3. Finally, 20,23(OH)2D3 inhibited the transcriptional activity of NF-kappaB in keratinocytes as demonstrated by EMSA, NF-kappaB-driven reporter gene activity assays and measurements of translocation of p65 from the cytoplasm to the nucleus. These inhibitory effects were connected with stimulation of the expression of IkappaBalpha with subsequent sequestration of NF-kappaB in the cytoplasm and consequent attenuation of transcriptional activity. In summary, we have characterized 20,23(OH)2D3 as a novel secosteroidal regulator of keratinocytes proliferation and differentiation and a modifier of their immune activity.

Evidence that vitamin D(3) promotes mast cell-dependent reduction of chronic UVB-induced skin pathology in mice

Mast cell production of interleukin-10 (IL-10) can limit the skin pathology induced by chronic low-dose ultraviolet (UV)-B irradiation. Although the mechanism that promotes mast cell IL-10 production in this setting is unknown, exposure of the skin to UVB irradiation induces increased production of the immune modifying agent 1alpha,25-dihydroxyvitamin D(3) (1alpha,25[OH](2)D(3)). We now show that 1alpha,25(OH)(2)D(3) can up-regulate IL-10 mRNA expression and induce IL-10 secretion in mouse mast cells in vitro. To investigate the roles of 1alpha,25(OH)(2)D(3) and mast cell vitamin D receptor (VDR) expression in chronically UVB-irradiated skin in vivo, we engrafted the skin of genetically mast cell-deficient WBB6F(1)-Kit(W/W-v) mice with bone marrow-derived cultured mast cells derived from C57BL/6 wild-type or VDR(-/-) mice. Optimal mast cell-dependent suppression of the inflammation, local production of proinflammatory cytokines, epidermal hyperplasia, and epidermal ulceration associated with chronic UVB irradiation of the skin in Kit(W/W-v) mice required expression of VDR by the adoptively transferred mast cells. Our findings suggest that 1alpha,25(OH)(2)D(3)/VDR-dependent induction of IL-10 production by cutaneous mast cells can contribute to the mast cell's ability to suppress inflammation and skin pathology at sites of chronic UVB irradiation.