Reno-endocrinal disorders: A basic understanding of the molecular genetics

The successful management of endocrine diseases is greatly helped by the complete understanding of the underlying pathology. The knowledge about the molecular genetics contributes immensely in the appropriate identification of the causative factors of the diseases and their subsequent management. The fields of nephrology and endocrinology are also interrelated to a large extent. Besides performing the secretory functions, the renal tissue also acts as target organ for many hormones such as antidiuretic hormone (ADH), atrial natriuretic peptides (ANP), and aldosterone. Understanding the molecular genetics of these hormones is important because the therapeutic interventions in many of these conditions is related to shared renal and endocrine functions, including the anemia of renal disease, chronic kidney disease, mineral bone disorders, and hypertension related to chronic kidney disease. Their understanding and in-depth knowledge is very essential in designing and formulating the therapeutic plans and innovating new management strategies. However, we still have to go a long way in order to completely understand the various confounding causative relationships between the pathology and disease of these reno-endocrinal manifestations.

Vitamin D deficiency in children living in Jeddah, Saudi Arabia

OBJECTIVE

Vitamin D deficiency is an unrecognized epidemic and a common health problem worldwide. This study was conducted to evaluate the vitamin D status in children living in Jeddah, Saudi Arabia and to study its relation to various variables.

MATERIALS AND METHODS

A cross-sectional study was conducted in the pediatric clinic in Jeddah Clinic Hospital-Kandarah, Jeddah, KSA, from October through December 2010, in which 510 healthy children aged 4-15 years were enrolled. Serum calcium, phosphorus, alkaline phosphatase and 25-hydroxyvitamin D [25(OH)D] were measured. Dietary vitamin D intake and duration of daily sunlight exposure were determined. 25(OH)D levels <20 ng/mL and <7 ng/mL were defined as relative and severe vitamin D deficiency, respectively.

RESULTS

The mean concentration of 25(OH)D was 13.07 ± 7.81 ng/mL. Seventy subjects (13.72%) had normal 25(OH)D level ranging 20-70 ng/mL. Three hundred (58.82%) had relative 25(OH)D deficiency and 140 (27.45%) had severe deficiency (P=0.000). 220 (43.14%) subjects were males and 290 (56.86%) were females having a statistically significant higher incidence of 25(OH)D deficiency (P=0.019). 54.9% were Saudis, 27.45% were Yemenis and 11.76% were Egyptians. Saudis and Yemenis were more subjected to 25(OH)D deficiency in comparison to Egyptians and other nationalities (P=0.01). There were significant inverse correlations between 25(OH)D levels and bony aches (P=0.000). 56.25% of asymptomatic children had vitamin D deficiency (P=0.000). Duration of sunlight exposure and daily intake of vitamin D had significant effects on serum level of vitamin D (P=0.000).

CONCLUSIONS

A high prevalence of vitamin D deficiency in children living in Jeddah was observed in this study. Vitamin D supplementation of food products can prevent vitamin D deficiency in these children.

Vitamin D deficiency in hemodialysis patients

BACKGROUND

Vitamin D [(25(OH)D] deficiency and insufficiency is common in patients with chronic kidney disease (CKD). 25(OH)D has been found to have beneficial effects on bone, cardiovascular and immune functions. There are little data about vitamin D levels in Indian patients on dialysis. This study was undertaken to determine the vitamin D status of Indian CKD patients on hemodialysis.

MATERIALS AND METHODS

We included 45 patients on maintenance hemodialysis coming to Medanta, Medicity, Gurgaon. 25(OH)D levels were measured with radioimmunoassay (Diasorin) method and parathyroid hormone (PTH) was measured using electrochemiluminiscence immunoassay (ECLIA).

RESULTS

The mean age of patients was 55 ± 13 years. 32/45 (71%) were males. 23/45 (51%) were diabetics. The median duration of hemodialysis was 5.5 months (range 1-74 months). 33/45 (74%) patients were on thrice weekly hemodialysis. The mean level of vitamin D was 10.14 ± 8.7 ng/ml. Majority of the patients [43/45 (95.5%)] were either vitamin D deficient or had insufficient levels. 40/45 (88.9%) were vitamin D deficient (levels <20 ng/ml); of these, 29/40 (64.4%) had severe vitamin D deficiency (levels <10 ng/ml) and 3/45 (6.7%) had insufficient levels (20-30 ng/ml) of vitamin D. Only 2/45 (4.4%) patients had normal levels of vitamin D. 23/45 (51%) of patients were receiving calcitriol. The mean levels of serum calcium, phosphorus, alkaline phosphatase, and albumin were 8.8 ± 0.64 mg/dl, 5.0 ± 0.7 mg/dl, 126 ± 10.3 IU/l and 3.6 ± 0.62 g/dl, respectively. PTH levels ranged from 37 to 1066 pg/ml, and the median was 195.8 pg/ml. There was a weak correlation between 25(OH)D levels and weight, sex, hemoglobin, albumin, alkaline phosphatase, and presence of diabetes. There was, however, no correlation with duration of dialysis or PTH levels.

CONCLUSION

Vitamin D deficiency and insufficiency are universal in our hemodialysis patients, with severe vitamin D deficiency in two-third of patients.

Vitamin D and its role during pregnancy in attaining optimal health of mother and fetus

Despite its discovery a hundred years ago, vitamin D has emerged as one of the most controversial nutrients and prohormones of the 21st century. Its role in calcium metabolism and bone health is undisputed but its role in immune function and long-term health is debated. There are clear indicators from in vitro and animal in vivo studies that point to vitamin D's indisputable role in both innate and adaptive immunity; however, the translation of these findings to clinical practice, including the care of the pregnant woman, has not occurred. Until recently, there has been a paucity of data from randomized controlled trials to establish clear cut beneficial effects of vitamin D supplementation during pregnancy. An overview of vitamin metabolism, states of deficiency, and the results of recent clinical trials conducted in the U.S. are presented with an emphasis on what is known and what questions remain to be answered.

25-Hydroxy vitamin D levels and endothelial vasodilator function in normotensive women

INTRODUCTION

Vitamin D was shown to be related to endothelial function and blood pressure. Reactive hyperaemia index (RHI) measurement by pulse arterial tonometry is a new method to evaluate vasodilator function of endothelium. We aimed to evaluate the relationship between vitamin D levels and RHI in women.

MATERIAL AND METHODS

We enrolled 56 normotensive, nonsmoker, normolipidemic and normoglycemic women, (23 with 25-OH-vitamin D levels>20 µg/l, and 33 with values lower than 20 µg/l). The cardiologist who was blind for vitamin D results executed measurements by pulse arterial tonometry. The measurement was performed on the lying patient with pre- and post-occlusion measurements of RHI by digital sensors placed on each index finger, by 5 min intervals. Pulse amplitudes were recorded, pre-occlusion and post-occlusion ratio was compared by the software of device. Stepwise linear regression and multiple regression analyses were performed to evaluate predictors of endothelial function.

RESULTS

The low vitamin D group had a lower RHI value than the normal vitamin D group (p = 0.042). In regression analysis, positive predictors of RHI were serum 25-OHD (β = 0.401; 95% CI 0.010-0.042, p = 0.002), serum albumin (β = 0.315; 95% CI 0.286-2.350, p = 0.013), and, inversely, serum calcium (β = -0.247; 95% CI (-1.347)-(-0.010), p = 0.047).

CONCLUSIONS

Serum 25-hydroxy vitamin D was significantly related to endothelial functions measured as RHI, even in healthy non-smoker women.

Evidence of associations between feto-maternal vitamin D status, cord parathyroid hormone and bone-specific alkaline phosphatase, and newborn whole body bone mineral content

In spite of a high prevalence of vitamin D inadequacy in pregnant women and neonates, relationships among vitamin D status (25(OH)D), parathyroid hormone (PTH), bone specific alkaline phosphatase (BALP), and whole body bone mineral content (WBBMC) in the newborn are poorly characterized. The purpose of the present study was to investigate the relationships between maternal and cord 25(OH)D, PTH, BALP, and WBBMC in newborns in a multiethnic population in Oakland, California and to evaluate the predictive value of the biochemical indices as indicators of WBBMC. Maternal and cord blood were collected from 80 mother-infant pairs and infant WBBMC was measured by dual energy X-ray absorptiometry 8-21 days post-birth. Cord PTH and BALP were each inversely correlated with infant WBBMC (r = -0.28, p = 0.01 and r = -0.26, p = 0.02) and with cord 25(OH)D (r = -0.24, p = 0.03 and r = -0.34, p = 0.002), while cord 25(OH)D and unadjusted or weight-adjusted WBBMC were not significantly correlated with one other. In multivariate regression modeling, infant WBBMC was most strongly predicted by infant weight (p < 0.0001), while either PTH or BALP contributed modestly but significantly to the model (p = 0.006 and p = 0.03 respectively). Cord 25(OH)D was not a significant predictor of infant WBBMC. This study provides evidence of associations between feto-maternal 25(OH)D, cord PTH and BALP, and early infant WBBMC, though neither feto-maternal 25(OH)D nor the measured biochemical indices were suitable indicators of WBBMC.

Effects of rituximab treatment on the serum concentrations of vitamin D and interleukins 2, 6, 7, and 10 in patients with rheumatoid arthritis

Background

Rituximab, a monoclonal antibody that selectively targets CD20-positive B-lymphocytes, is used for the treatment of patients with rheumatoid arthritis (RA) with an inadequate response or tolerance to tumor necrosis factor inhibitors. The objective of this study was to investigate the effects of rituximab treatment on the serum concentrations of vitamin D, interleukin (IL) 2, IL-6, IL-7, and IL-10 in patients with rheumatoid arthritis (RA).

Methods

Forty-five patients, aged 25–78 years, were enrolled into a cohort prospective study. All patients were treated with intravenous rituximab. Disease activity score-28 (DAS-28) and serum concentrations of rheumatoid factor (RF), C-reactive protein (CRP), anticyclic citrullinated peptide (anti-CCP), erythrocyte sedimentation rate (ESR), health assessment questionnaire (HAQ), vitamin D, ILs 2, 6, 7, and 10 were estimated in the patients before and after treatment with rituximab.

Results

DAS-28, HAQ score, and serum concentrations of CRP, RF, anti-CCP, IL-2, IL-6, IL-7, IL-10, and ESR significantly decreased after treatment. All 45 patients had vitamin D deficiency before treatment and this did not significantly change after treatment. However no significant association was found among serum vitamin D concentration and any of the ILs.

Conclusion

We concluded from this study that although rituximab treatment of patients with RA significantly reduced their disease activity and serum concentrations of IL-2, IL-6, IL-7, and IL-10, it did not significantly alter their vitamin D status. Furthermore, no significant association was found among serum vitamin D concentration and any of the ILs.

Focus on vitamin D, inflammation and type 2 diabetes. Nutrients. 2012;4:52-67. [PMID: 22347618 PMCID: PMC3277101 DOI: 10.3390/nu4010052]

The initial observations linking vitamin D to type 2 diabetes in humans came from studies showing that both healthy and diabetic subjects had a seasonal variation of glycemic control. Currently, there is evidence supporting that vitamin D status is important to regulate some pathways related to type 2 diabetes development. Since the activation of inflammatory pathways interferes with normal metabolism and disrupts proper insulin signaling, it is hypothesized that vitamin D could influence glucose homeostasis by modulating inflammatory response. Human studies investigating the impact of vitamin D supplementation on inflammatory biomarkers of subjects with or at high risk of developing type 2 diabetes are scarce and have generated conflicting results. Based on available clinical and epidemiological data, the positive effects of vitamin D seem to be primarily related to its action on insulin secretion and sensitivity and secondary to its action on inflammation. Future studies specifically designed to investigate the role of vitamin D on type 2 diabetes using inflammation as the main outcome are urgently needed in order to provide a more robust link between vitamin D, inflammation and type 2 diabetes.

The Vitamin D Receptor, Inflammatory Bowel Diseases, and Colon Cancer

The nuclear receptor is an emerging therapeutic target in various human diseases. Vitamin D receptor (VDR), a nuclear receptor, mediates the biological functions of vitamin D. Classically, vitamin D is recognized as an essential contributor to mineral and bone homeostasis. Increasing evidence demonstrates that vitamin D is involved in inflammatory responses. Persistent intestinal inflammation is associated with colon cancer. This review focuses on vitamin D and VDR in inflammatory bowel diseases and colon cancer. We place emphasis on the regulatory roles of vitamin D/VDR on in inflammation, enteric bacteria, and tumorigenesis. We summarize the signaling pathways regulated by VDR in intestinal homeostasis. Finally, we discuss the potential application of the insights gleaned from these findings to personalized therapies in chronic inflammation and colon cancer.

Theobald palm and his remarkable observation: how the sunshine vitamin came to be recognized

The seminal discovery that sunlight was important in the prevention of nutritional rickets was made in 1890 by Theobald A. Palm, a medical missionary who contrasted the prevalence of rickets in northern European urban areas with similar areas in Japan and other tropical countries. He surmised that exposure to sunlight prevented rickets. Over the next 40 years his observation led to an understanding of ultraviolet irradiation and its role in vitamin D synthesis. This opened a new era of appreciation for the curative powers of the sun and "the sunshine vitamin". While Palm's observations were in some ways obscure, they had a potent effect on the development of photobiology.

Vitamin D and allergic disease: sunlight at the end of the tunnel?

A role for vitamin D in the regulation of immune function was first proposed after the identification of Vitamin D receptors in lymphocytes. It has since been recognized that the active form of vitamin D, 1α,25(OH)₂D₃, has direct affects on naïve and activated helper T cells, regulatory T cells, activated B cells and dendritic cells. There is a growing body of literature linking vitamin D (serum 25(OH)D, oral intake and surrogate indicators such as latitude) to various immune-related conditions, including allergy, although the nature of this relationship is still unclear. This review explores the findings of epidemiological, clinical and laboratory research, and the potential role of vitamin D in promoting the inappropriate immune responses which underpin the rise in a broad range of immune diseases.

The initiative on hip fractures of the Veneto Region

OBJECTIVE

to assess the prevalence of the most relevant environmental and individual risk factors in subjects with a recent hip fracture was the aim of this observational study promoted by the Health Authorities of the Regione Veneto (Italy).

METHODS

patients aged > 60 years of both genders with a recent hip fracture not associated with malignancies, were administered questionnaires on dietary habits, sun exposure, disability score. A complete family, pharmacological and pathology history was collected together with previous falls, details of the fracture index, anthropometric data. In a subgroup of patients blood was taken for the measurements of serum 25 hydroxy-vitamin D (25OHD).

RESULTS

the study includes 704 patients (573 women and 131 men). Mean age was 81±8 years (range 60-102). Severe pre-fracture disability was a common feature (58%) associated with multiple co-morbidities (84%), more frequently cardiovascular and neurological diseases, and specific medications. In a large proportion (86%) of the patients environmental or individual risk factors for falling were found. Vitamin D insufficiency was quite common, particularly in the regional Health Districts were strategies for preventing vitamin D deficiency were not implemented. Only a small proportion (17%) of the study population had been evaluate and treated for osteoporosis.

CONCLUSIONS

in senile patients with a recent hip fracture pre-existing disability, multiple co-morbidities, high risk of falling and inadequate intake of calcium and vitamin D was quite common. Community and case-finding interventions are highly warranted.

On the roles of solar UV irradiance and smoking on the diagnosis of second cancers after diagnosis of melanoma

Several recent papers have reported standardized incidence ratios (SIRs) for second cancers after diagnosis of cutaneous malignant melanoma. This review divides the types of cancer into five types: (1) those for which UV-B (UVB) irradiance and vitamin D reduces risk; (2) those for which UVB/vitamin D reduces risk and smoking increases risk; (3) smoking related; (4) unknown UVB/vitamin D and smoking sensitivity and (5) those for which UV irradiance increases risk. For those in category 1, SIRs were either significantly elevated or not significantly different from 1.0. For those in category 2, the SIR for kidney cancer was significantly elevated, whereas the SIRs for cervical, laryngeal and rectal cancer were significantly reduced. For those in category 3, all SIRs were significantly reduced. For those in categories 4 and 5, SIRs for all types except lip cancer were significantly elevated. A registry linkage study found significantly reduced SIRs for second cancers after diagnosis of nonmelanoma skin cancer in sunny countries but found increased SIRs in less sunny countries. The SIRs for second cancer for melanoma were elevated in both sunny and less sunny countries. This review concludes that sun exposure without sufficient vitamin D production may explain the elevated SIRs for vitamin D-sensitive cancers, whereas smoking-through production of skin elastosis, thereby reducing the risk of melanoma-probably explains the findings for smoking-related cancers. Thus, guidelines on UV irradiance should emphasize regular moderate UVB irradiance rather than avoidance for those who can tan.

Association Between Vitamin D Dosing Regimen and Fall Prevention in Long-term Care Seniors

INTRODUCTION

The effectiveness of vitamin D in reducing falls among long-term care (LTC) seniors remains nonconclusive. We reviewed how vitamin D dosing regimen could affect rate of fall and number of fallers among LTC seniors.

METHODS

We conducted a systematic literature review. Studies were selected by two independent reviewers based on study characteristics (age 75 or older), quality assessment (primary analysis randomized controlled trials), and outcome (rate of fall and number of fallers). Analyses of all trials following trials using daily standard dosage (800-1000 IU) only were performed to compare daily standard dosage with intermittent supratherapeutic dosage in fall prevention.

RESULTS

Seventy-nine studies were identified, with 28 selected by reviewers (kappa 0.98), and four RCT were conducted in LTC. Daily standard dosage provides greater reduction in rate of fall by 16%, which was statistically significant. However, reduction in number of fallers remained statistically insignificant even taking dosing regimen into account.

CONCLUSIONS

Daily standard dosage of vitamin D has greater benefits in reducing fall rate than that of intermittent supratherapeutic doses, but not in number of fallers. This could imply that vitamin D is useful in preventing fall recurrence rather than first fall. Prospective studies randomizing LTC seniors to different dosing regimens are warranted.

Epigenetic regulation of fetal bone development and placental transfer of nutrients: progress for osteoporosis

Osteoporosis is a common age-related disorder and causes acute and long-term disability and economic cost. Many factors influence the accumulation of bone minerals, including heredity, diet, physical activity, gender, endocrine functions, and risk factors such as alcohol, drug abuse, some pharmacological drugs or cigarette smoking. The pathology of bone development during intrauterine life is a factor for osteoporosis. Moreover, the placental transfer of nutrients plays an important role in the building of bones of fetuses. The importance of maternal calcium intake and vitamin D status are highlighted in this review. Various environmental factors including nutrition state or maternal stress may affect the epigenetic state of a number of genes during fetal development of bones. Histone modifications as histone hypomethylation, histone hypermethylation, hypoacetylation, etc. are involved in chromatin remodeling, known to contribute to the epigenetic landscape of chromosomes, and play roles in both fetal bone development and osteoporosis. This review will give an overview of epigenetic modulation of bone development and placental transfer of nutrients. In addition, the data from animal and human studies support the role of epigenetic modulation of calcium and vitamin D in the pathogenesis of osteoporosis. We review the evidence suggesting that various genes are involved in regulation of osteoclast formation and differentiation by osteoblasts and stem cells. Epigenetic changes in growth factors as well as cytokines play a rol in fetal bone development. On balance, the data suggest that there is a link between epigenetic changes in placental transfer of nutrients, including calcium and vitamin D, abnormal intrauterine bone development and pathogenesis of osteoporosis.

Vitamin D receptor (VDR) polymorphisms and skin cancer: A systematic review

Skin cancer is the most common cancer in humans. There are several types of skin cancer that include basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and malignant melanoma (MM). The associations of vDr polymorphisms with skin cancer risk are not well characterized so far. Only a few epidemiologic studies have directly addressed the relationship between VDR polymorphisms and the incidence and prognosis of MM. To make the most of the available information on VDR polymorphisms and skin cancer (MM, BCC and SCC), we undertook a systematic review of published studies. In conclusion, data summarized in this review support the concept that the vitamin D endocrine system (VDES) is of importance for pathogenesis and progression of MM and other types of skin cancer.

Hip fracture history and risk of nonmelanoma skin cancer: a Danish population-based study

Background

Vitamin D deficiency is associated with osteoporotic fractures, such as hip fracture. Sun exposure, the natural source of vitamin D, is the main risk factor for basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). In this study, we examined the association between a history of hip fracture and risk of BCC and SCC.

Methods

We conducted a population-based case-controlled study using data on BCC and SCC cases registered in the Danish Cancer Registry from 1990–2005. For each case, we selected five population controls matched by age and gender. We used conditional logistic regression to compute odds ratios (OR) and 95% confidence intervals (CI), while adjusting for chronic diseases and socioeconomic status.

Results

A history of hip fracture was associated with a decreased risk of BCC (OR 0.90, 95% CI 0.85–0.94), which was most pronounced in cases of tumors on the trunk, extremities, or at multiple sites. We found no association for SCC (OR 1.07, 95% CI 0.98–1.17).

Conclusion

Our study showed an inverse association between history of hip fracture and risk of BCC, but not of SCC. Sun exposure, resulting in vitamin D synthesis, may explain the link between the two diseases.

Renin-angiotensin system activity in vitamin D deficient, obese individuals with hypertension: An urban Indian study

BACKGROUND

Elevated renin-angiotensin-aldosterone system (RAAS) activity is an important mechanism in the development of hypertension. Both obesity and 25-hydroxy vitamin D [25(OH)D] deficiency have been associated with hypertension and augmented renin-angiotensin system (RAS) activity. We tried to test the hypothesis that vitamin D deficiency and obesity are associated with increased RAS activity in Indian patients with hypertension.

MATERIALS AND METHODS

Fifty newly detected hypertensive patients were screened. Patients with secondary hypertension, chronic kidney disease, or coronary artery disease were excluded. Patients underwent measurement of vitamin D and plasma renin and plasma aldosterone concentrations. They were divided into three groups according to their baseline body mass index (BMI; normal <25 kg/m(2), overweight 25-29.9 kg/m(2) and obese ≥30 kg/m(2)) and 25(OH)D levels (deficient <20 ng/ml, insufficient 20-29 ng/ml and optimal ≥30 ng/ml).

RESULTS

A total of 50 (male:female - 32:18) patients were included, with a mean age of 49.5 ± 7.8 years, mean BMI of 28.3 ± 3.4 kg/m(2) and a mean 25(OH)D concentration of 18.5 ± 6.4 ng/ml. Mean systolic blood pressure (SBP) was 162.4 ± 20.2 mm Hg and mean diastolic blood pressure (DBP) was 100.2 ± 11.2 mm Hg. All the three blood pressure parameters [SBP, DBP and mean arterial pressure (MAP)] were significantly higher among individuals with lower 25(OH)D levels. The P values for trends in SBP, DBP and MAP were 0.009, 0.01 and 0.007, respectively. Though all the three blood pressure parameters (SBP, DBP and MAP) were higher among individuals with higher BMIs, they were not achieving statistical significance. Increasing trends in PRA and PAC were noticed with lower 25(OH)D and higher BMI levels.

CONCLUSION

Vitamin D deficiency and obesity are associated with stimulation of RAAS activity. Vitamin D supplementation along with weight loss may be studied as a therapeutic strategy to reduce tissue RAS activity in individualswith Vitamin D deficiency and obesity.

The relationship between calcium metabolism, insulin-like growth factor-1 and pulse pressure in normotensive, normolipidaemic and non-diabetic patients

INTRODUCTION

Recent evidence suggests an interaction between bone metabolism and blood pressure (BP) regulation. The aim of our study was to evaluate endocrinological and metabolic factors related to pulse pressure (PP) in normotensive, normolipidaemic, non-smoker subjects.

MATERIAL AND METHODS

We consecutively enrolled 156 adults (37 males, 119 females) in summer 2009. The BP and body mass index (BMI) were recorded, and serum samples were taken for 25-hydroxy vitamin D (25-OHD), insulin-like growth factor-1 (IGF-1), growth hormone (GH), parathormone (PTH), calcium, albumin, phosphorus, glucose, triglyceride and cholesterol levels.

RESULTS

In the postmenopausal group, PP was significantly associated with age and BMI, while in premenopausal patients it was inversely related to ionized calcium. In men, a reverse relationship was present between GH and IGF-1 levels and PP.

CONCLUSIONS

The PP was predicted by different parameters in different genders and these predictors change even in the same gender before and after menopause. Well-known predictors of PP such as age and BMI were more pronounced in postmenopausal women, but none of the groups showed a relationship between PP and 25-OHD or PTH.

Antimicrobial implications of vitamin D

Evidence exists that vitamin D has a potential antimicrobial activity and its deficiency has deleterious effects on general well-being and longevity. Vitamin D may reduce the risk of infection through multiple mechanisms. Vitamin D boosts innate immunity by modulating production of anti-microbial peptides (AMPs) and cytokine response. Vitamin D and its analogues via these mechanisms are playing an increasing role in the management of atopic dermatitis, psoriasis, vitiligo, acne and rosacea. Vitamin D may reduce susceptibility to infection in patients with atopic dermatitis and the ability to regulate local immune and inflammatory responses offers exciting potential for understanding and treating chronic inflammatory dermatitides. Moreover, B and T cell activation as well as boosting the activity of monocytes and macrophages also contribute to a potent systemic anti-microbial effect. The direct invasion by pathogenic organisms may be minimized at sites such as the respiratory tract by enhancing clearance of invading organisms. A vitamin D replete state appears to benefit most infections, with the possible noteworthy exception of Leishmaniasis. Antibiotics remain an expensive option and misuse of these agents results in significant antibiotic resistance and contributes to escalating health care costs. Vitamin D constitutes an inexpensive prophylactic option and possibly therapeutic product either by itself or as a synergistic agent to traditional antimicrobial agents. This review outlines the specific antimicrobial properties of vitamin D in combating a wide range of organisms. We discuss the possible mechanisms by which vitamin D may have a therapeutic role in managing a variety of infections.

Solar UV doses of adult Americans and vitamin D(3) production

BACKGROUND

Sunlight contains UV radiation that affects human health in both detrimental (skin cancers) and beneficial (vitamin D(3)) ways. An evaluation of the vitamin D status of adult Americans (22-40, 41-59, 60+ yr) show many have deficient or insufficient serum levels of 25-hydroxyvitamin D, indicating they are not getting enough from dietary sources or sunlight. Those findings are in conflict with calculated values from the American Academy of Dermatology who insist people make "ample" vitamin D(3) (≥1,000 IU/day) from their "casual," or everyday, outdoor UV exposures even if they use sunscreens with sun protection factor 15.

OBJECTIVE

We investigated this situation using the everyday outdoor UV doses of indoor-working adult Americans (∼7,000) in the north (45°N) and south (35°N) to calculate how much vitamin D(3) they produce each season with and without vacationing.

RESULTS

Only during the summer can skin type II Caucasian adults (21-59 yr) meet their minimum (600 IU/day) vitamin D(3) needs from everyday exposures, but only if they do not wear professional clothes or sunscreens (except beach vacations).

METHOD

To do vitamin D(3) calculations properly, we used action spectrum and geometric conversion factors, not previously incorporated into other calculations.

CONCLUSIONS

Most adult Americans do not go outside enough to meet their minimum or optimum (≥1,200 IU/day) vitamin D(3) needs all year. The darker skin types (III-VI) and the oldest people (>59 yr) are at the highest risk for not making enough vitamin D(3) during the year from everyday outdoor exposures even with a 2-3 week summer vacation.

Renoprotective effects of Vitamin D and renin-angiotensin system

Vitamin D has many physiological functions. First it is a primary regulator of calcium homeostasis. Beyond that, vitamin D and its receptors (VDR) play important role in the immune system, cardiovascular system, reproductive system and insulin resistance. An important aspect of vitamin D pleiotropic effects is the interaction with components of the renin-angiotensin system (RAS). It was demonstrated that vitamin D-null mice have a sustained elevation of renin expression. The combination of both the AT1 blockers and the vitamin D analogues, leads to a marked amelioration of the molecular and clinical markers of diabetic nephropathy. This combination may protect the kidney through the effects on both the glomerular and the tubulointerstitial compartments. There are different studies that corroborate the renoprotective action of vitamin D in CKD. In fact the renoprotective mechanisms in humans remain to be assessed, but these are realized through reduction of proteinuria, high blood pressure, inflammation as well as hemodynamic effects. An important mechanism is the role of vitamin D as a potent negative endocrine regulator of renin expression. It was shown that low levels of vitamin D represent a novel risk factor for the progression of renal disease but it is not demonstrated yet that vitamin D can prolong the time to end-stage renal disease. This question remains to be answered in other future controlled clinical trials.

The thyroid hormone, parathyroid hormone and vitamin D associated hypertension

Thyroid disorders and primary hyperparathyroidism have been known to be associated with increases in blood pressure. The hypertension related to hypothyroidism is a result of increased peripheral resistance, changes in renal hemodynamics, hormonal changes and obesity. Treatment of hypothyroidism with levo-thyroxine replacement causes a decrease in blood pressure and an overall decline in cardiovascular risk. High blood pressure has also been noted in patients with subclinical hypothyroidism. Hyperthyroidism, on the other hand, is associated with systolic hypertension resulting from an expansion of the circulating blood volume and increase in stroke volume. Increased serum calcium levels associated with a primary increase in parathyroid hormone levels have been also associated with high blood pressure recordings. The mechanism for this is not clear but the theories include an increase in the activity of the renin-angiotensin-aldosterone system and vasoconstriction. Treatment of primary hyperparathyroidism by surgery results in a decline in blood pressure and a decrease in the plasma renin activity. Finally, this review also looks at more recent evidence linking hypovitaminosis D with cardiovascular risk factors, particularly hypertension, and the postulated mechanisms linking the two.

Successful treatment of reactive airways dysfunction syndrome by high-dose vitamin D

Reactive airways dysfunction syndrome is a controversial and poorly understood condition produced by inhalational injury from gas, vapors, or fumes. The symptoms mimic asthma, but appear unresponsive to asthma treatments. If symptoms persist for more than 6 months, there is a risk that they can become chronic. For these cases, effective treatments are lacking and quality of life is poor. We describe the first use of high-dose vitamin D in a patient with this condition, who fulfilled the 1995 American College of Chest Physicians criteria for this syndrome. The patient we describe presented an extremely difficult management problem and was refractory to conventional treatments, but responded to high-dose oral vitamin D supplements.

Seasonal variation of vitamin D and HbA(1c) levels in patients with type 1 diabetes mellitus in the Middle East

INTRODUCTION

The discovery that many tissues express the vitamin D receptor and are able to transform the 25-hydroxyvitamin D into 1,25-dihydroxyvitamin D (active metabolite) has led to the hypothesis that vitamin D could have a role in the pathogenesis and prevention of diabetes mellitus. Accumulating evidence has linked vitamin D deficiency with immunological disturbance in type 1 diabetes mellitus. Several epidemiological studies have shown lower serum 25-hydroxyvitamin D concentrations in diabetic individuals compared to nondiabetic individuals.

PATIENTS AND METHODS

A total of 105 Lebanese patients with type 1 diabetes mellitus were recruited. Levels of HbA(1c) and vitamin D were recorded during two phases with phase 1 being the period from June-September 2009 and phase 2 from January-April 2009.

RESULTS

Vitamin D levels at the end of sunny season (phase 2), reflecting the previous sunny months, were found to be higher than in the early summer season (phase 1) reflecting the previous cloudy months season, with a mean change of 0.70 ± 6.87 ng/mL (P = 0.029). HbA(1c) levels were higher in phase 2 than in phase 1 with an increase of 0.175% ± 1.46% (P = 0.113).

CONCLUSION

Vitamin D levels were higher at the end of the sunny season than at the end of cloudy season. HbA(1c) was also lower (but not significantly so) in the early summer season (cloudy months). There was a weak correlation between seasonal changes of vitamin D levels and the control of blood glucose as monitored by HbA(1c) in a cohort of Lebanese patients with type 1 diabetes mellitus.

Mineral and bone disorders in chronic kidney disease and end-stage renal disease patients: new insights into vitamin D receptor activation

Progressive loss of kidney function leads to reduced production of calcitriol (1,25-dihydroxyvitamin D; active vitamin D) and an imbalance in serum calcium (Ca) and phosphorus (P) levels, which are associated with progression of renal failure as well as increased rates of cardiovascular (CV) events and mortality. In addition, multifactorial hypocalcemia and resistance to parathyroid hormone (PTH) can lead to prolonged and excessive synthesis and secretion of PTH, eventually leading to development of secondary hyperparathyroidism and renal osteodystrophy. These changes associated with chronic kidney disease (CKD), extending beyond bone and related biochemical abnormalities, have prompted the development of the term CKD–mineral and bone disorder to describe its systemic nature. Excessive P loading, among other factors, will promote vascular calcification (VC), and PTH production will affect bone remodeling. Although administration of calcitriol increases serum Ca levels and decreases PTH, it is also associated with elevated Ca × P product. Therefore, compounds that selectively activate vitamin D receptors (VDR activators), potentially reducing Ca–P toxicity and distinctly affecting pathogenic mechanisms of VC, might enhance CV and renal protection, increase the vitamin D therapeutic window, and thus provide a significant clinical benefit. Moreover, selective VDR activators have been associated with improvement in survival, at least among dialysis patients. Thus, selective VDR activators should be considered a novel and interesting approach to enhance the standard of care in CKD patients.

The Effects of Olmesartan and Alfacalcidol on Renoprotection and klotho Gene Expression in 5/6 Nephrectomized Spontaneously Hypertensive Rats

Recently, an angiotensin inhibitor has been shown to upregulate the klotho mRNA level in chronic renal failure. In addition, the administration of vitamin D has been reported to improve the mortality of patients with chronic renal failure. In this study, we examined the effects of an angiotensin inhibitor and/or vitamin D on the progression of chronic renal failure by using male 5/6 nephrectomized (5/6Nx) spontaneously hypertensive rats. Male 5/6Nx spontaneously hypertensive rats were assigned to 4 groups as follows: 5/6Nx group, 5/6Nx rats; Alf group, 5/6Nx rats administered alfacalcidol (0.2 μg/kg/day); Olm group, 5/6Nx rats administered olmesartan (15 mg/kg/day); Alf + Olm group, 5/6Nx rats administered alfacalcidol (0.2 μg/kg/day) and olmesartan (15 mg/kg/day). These drugs were administered for 12 weeks. Systolic blood pressure in the Alf, Olm and Alf + Olm groups were significantly decreased relative to that in the 5/6Nx group during the 12-week experimental period. As a result, all treated groups showed renoprotection based on improvement of the systolic blood pressure, urinary protein excretion and histological renal fibrosis. Combination therapy of alfacalcidol and olmesartan was more effective than either alfacalcidol or olmesartan alone. Expression of klotho mRNA was significantly upregulated in the Alf + Olm group in comparison with in the 5/6Nx group. Serum levels of fibroblast growth factor 23 in the Alf group and the Alf + Olm group were significantly higher than those in the 5/6Nx group and the Olm group. In conclusion, the combination of Olm and Alf inhibited the progression of renal damage in the 5/6Nx group through the strong antihypertensive effect as well as the upregulation of the klotho gene.

Osteoporosis and Parkinson's disease

Parkinson's disease (PD) and osteoporosis are two conditions with a quite high prevalence in older people. From the literature we learn that in parkinsonian people there a is e major reduction of Bone Mass Density (BMD) compared to age-matched controls. A low BMD is one of the factors related to fracture's frequency in PD patients besides an increased risk of falls. From the standpoint pathophysiology, various factors are involved in osteoporosis: immobilization, endocrine factors like hypovitaminosis D, nutritional and iatrogenic factors.Considering morbidity and mortality related to fractures in old people and in particular in PD patients it is reasonable that these patients would undergo to vitamin and BMD measuring, to fall risk assessment and that all preventive measure are implemented to reduce the risk of fractures. Possible interventions are essentially based on fall prevention and treatment of osteoporosis. Randomized clinical studies in the literature, in which it was studied the effect of anti-osteoporotic drugs in patients with MP showed a significant reduction in the number of fractures and increase BMD.

Vitamin d and susceptibility of chronic lung diseases: role of epigenetics

Vitamin D deficiency is linked to accelerated decline in lung function, increased inflammation, and reduced immunity in chronic lung diseases. Epidemiological studies have suggested that vitamin D insufficiency is associated with low lung function in susceptible subjects who are exposed to higher levels of environmental agents (airborne particulates). Recent studies have highlighted the role of vitamin D and vitamin D receptor (VDR) in regulation of several genes that are involved in inflammation, immunity, cellular proliferation, differentiation, and apoptosis. Vitamin D has also been implicated in reversal of steroid resistance and airway remodeling, which are the hallmarks of chronic obstructive pulmonary disease (COPD) and severe asthma. VDR protein level is decreased in lungs of patients with COPD. VDR deficient mice develop an abnormal lung phenotype with characteristics of COPD, such as airspace enlargement and decline in lung function associated with increased lung inflammatory cellular influx, and immune-lymphoid aggregates formation. Dietary vitamin D may regulate epigenetic events, in particular on genes which are responsible for COPD susceptibility. Active metabolite of vitamin D, 1,25-dihydroxyvitamin D₃ plays an essential role in cellular metabolism and differentiation via its nuclear receptor (VDR) that cooperates with several other chromatin modification enzymes (histone acetyltransferases and histone deacetylases), thereby mediating complex epigenetic events in vitamin D signaling and metabolism. This review provides an update on the current knowledge and understanding on vitamin D, and susceptibility of chronic lung diseases in relation to the possible role of epigenetics in its molecular action. Understanding the molecular epigenetic mechanism of vitamin D/VDR would provide rationale for dietary vitamin D-mediated intervention in prevention and management of chronic lung diseases linked with vitamin D deficiency.

Association between vitamin D and pressure ulcers in older ambulatory adults: results of a matched case-control study

Background

Pressure ulcers are common among older adults, but knowledge about nutritional risk factors is still developing. Vitamin D deficiency is common in the elderly population and is required for normal skin proliferation. The role of vitamin D in pressure ulceration and wound healing is not known. The purpose of this case–control study was to determine the association between vitamin D levels and pressure ulceration in an older community-dwelling cohort.

Methods

All cases and controls were community-dwelling elderly older than 60 years in a primary care panel in Olmsted County, MN. Pressure ulcer cases were defined clinically. The controls were age-matched and gender-matched to controls without pressure ulceration. The main exposure variable was 25-hydroxyvitamin D levels in both groups. The other exposure variable was the Charlson Comorbidity Index used to measure medical comorbidity. The analysis included univariate and conditional logistic regression for 25-hydroxyvitamin D levels.

Results

The average (standard deviation) age of the study participants with a pressure ulcer was 80.46 years (±8.67), and the average vitamin D level was 30.92 ng/mL (±12.46). In univariate analysis, Vitamin D deficiency (levels < 25 ng/mL) was associated with pressure ulcers (odds ratio: 1.871, P = 0.0154). Comorbidities of the subjects calculated using the Charlson Comorbidity Index were also associated with pressure ulcers (odds ratio: 1.136, P < 0.001). In the final conditional logistical regression model, the association of Vitamin D and pressure ulcers became nonsignificant after adjustment for comorbid illness.

Conclusion

Medical comorbidities increased the risk of pressure ulceration. Vitamin D deficiency was not an independent risk factor for pressure ulceration, and may be a marker of comorbid illness.

The prevalence of vitamin D deficiency and relationship with fracture risk in older women presenting in Australian general practice

AIM

To investigate vitamin D status among older women and to explore relationships between vitamin D and fracture risk and vertebral fractures.

METHODS

A total of 267 general practitioners recruited 2466 women aged >70 years with no known osteoporosis or fragility fracture. Serum 25-hydroxy vitamin D (25(OH)D), bone mineral density by dual-energy X-ray absorptiometry (DXA) and vertebral fracture on thoracolumbar X-ray were determined.

RESULTS

A total of 2368 women, median age 76 years, provided data and of these 13% were on vitamin D supplements. 25(OH)D levels were available for 907 (44.1%) of those not taking vitamin D. 88.3% of these had a level below 75 nmol/L. Serum 25(OH)D was negatively associated with age (P = 0.003) and body mass index (P < 0.001), and positively associated with lower latitude, femoral neck DXA T-score (P = 0.044) and being Caucasian (P < 0.001).

CONCLUSIONS

The vitamin D status of community-dwelling older Australian women is inadequate, yet the use of supplements is low.

Influenza, solar radiation and vitamin D

The annual death numbers of influenza and pneumonia in Norway were studied for the time period 1980-2000. No direct relationships were found with the variations of the annual UVB fluences, probably due to the fact that these variations did not exceed 30%. However, there was a very pronounced seasonal variation of both influenza deaths and pneumonia deaths, the vast majority occurring during the winter. Vitamin D levels were also estimated from several publications. The data support the hypothesis that a high vitamin D level, as that found in the summer, acts in a protective manner with respect to influenza as well as pneumonia. The findings are discussed and compared with data from tropical and subtropical areas.

An estimate of the survival benefit of improving vitamin D status in the adult german population

BACKGROUND

Inadequate vitamin D status is a worldwide problem. Evidence is accumulating that individuals with low vitamin D status have excess mortality rates. We calculated to which extent annual mortality rates can be reduced in the German population by optimizing vitamin D status.

RESULTS

Mean serum concentrations of 25-hydroxyvitamin D in the DEVID study cohort were 41 nmol/l (SD: 22 nmol/l). More than 90% of individuals had 25-hydroxyvitamin D concentrations below the threshold that was associated with lowest mortality risk in the two aforementioned trials (75 nmol/l). According to conservative estimations, at least 2.2% of all deaths or 18,300 lives annually can be saved by achieving 25(OH)D concentrations of at least 75 nmol/l in the entire adult German population. Available data provide evidence for an exponential increase in total mortality with deficient 25-hydroxyvitamin D concentrations.

METHODS

Our calculations are based on (1) an annual mortality rate of 1.34% in the adult German population as provided by the Statistical Yearbook, (2) the actual vitamin D status in German adults with a high mortality risk as assessed in 1,343 individuals from 264 general practitioners in different German regions (DEVID study), and (3) data from two very large prospective cohorts (Dobnig et al. 2008; Melamed et al. 2008) about the excess mortality in individuals with inadequate vitamin D status.

CONCLUSION

Improving vitamin D status in a population with inadequate vitamin D status might be an effective strategy to reduce annual mortality rates.

The possible roles of solar ultraviolet-B radiation and vitamin D in reducing case-fatality rates from the 1918-1919 influenza pandemic in the United States

Deaths during the 1918-1919 influenza pandemic have been linked to both the influenza virus and secondary bacterial lung infections. Case fatality rates and percentage of influenza cases complicated by pneumonia were available from survey data for twelve United States locations in the 1918-1919 pandemic. This study analyzes case fatality rates and cases complicated by pneumonia with respect to estimated summertime and wintertime solar ultraviolet-B (UVB) doses as indicators of population mean vitamin D status. Substantial correlations were found for associations of July UVB dose with case fatality rates (r = -0.72, p = 0.009) and rates of pneumonia as a complication of influenza (r = -0.77, p = 0.005). Similar results were found for wintertime UVB. Vitamin D upregulates production of human cathelicidin, LL-37, which has both antimicrobial and antiendotoxin activities. Vitamin D also reduces the production of proinflammatory cytokines, which could also explain some of the benefit of vitamin D since H1N1 infection gives rise to a cytokine storm. The potential role of vitamin D status in reducing secondary bacterial infections and loss of life in pandemic influence requires further evaluation.

The role of vitamin D and SLCO1B1*5 gene polymorphism in statin-associated myalgias

Myalgias are the most common side effect of statin use and the commonest cause for discontinuing therapy. Vitamin D has known physiologic functions in muscle and vitamin D deficiency is known to cause myalgias, with its correction leading to disappearance of muscle symptoms. The 521T>C SLCO1B1*5 gene polymorphism decreasing function in the gene coding for a liver anion transporter that is responsible for statin uptake has been found to explain the majority of statin-associated muscle symptoms. Patients with statin-associated myalgias have been reported to improve with vitamin D supplementation. We therefore investigated (i) whether repletion of vitamin D in deficient patients with myalgias could lead to tolerance for subsequent statin therapy and (ii) whether vitamin D status modifies the effect of the SLCO1B1*5 genotype on myalgia risk. Using a retrospective cohort of 64 patients in whom 25-hydroxyvitamin D [25(OH)D] had been measured for any reason while on statin therapy, including 46 patients who consented to be genotyped, we found strong evidence showing that repletion of vitamin D in vitamin D deficient patients improved myalgias. Of 21 vitamin D deficient patients with intolerable statin-associated myalgias, 14 of 15 rechallenged with statins were subsequently symptomfree, with one patient experiencing mild and tolerable symptoms, far exceeding expected rates of acquired tolerability with no therapy (p = 0.01). In addition, while the SLCO1B1*5 genotype was associated with a three-fold increased risk of myalgias (p = 0.07), this risk was not found to differ by vitamin D status (p = 0.60).

Fundamental questions to sun protection: A continuous education symposium on vitamin D, immune system and sun protection at the University of Zürich

Since exposure to sunlight is a main factor in the development of non-melanoma skin cancer and there are associations between malignant melanoma and short-term intense ultraviolet (UV) exposure, particularly burning in childhood, strict protection from UV-radiation is recommended. However, up to 90% of all requisite vitamin D has to be formed within the skin through the action of the sun-a serious problem, for a connection between vitamin D deficiency, demonstrated in epidemiological studies, and various types of cancer and other diseases has been confirmed. A UVB-triggered skin autonomous vitamin D(3) synthesis pathway has recently been described, producing the active Vitamin D metabolite calcitriol. This cutaneous vitamin D(3) pathway is unique. Keratinocytes and dendritic cells can convert vitamin D to calcitriol. Cutaneous T cells activated in the presence of calcitriol express the chemokine receptor CCR10 attracting them to the chemokine CCL27 that keratinocytes express selectively in the epidermis, and migrate from dermal layers of the skin to the epidermis under UV radiation. Thus, calcitriol has endocrine roles beyond its calciotropic action, including cell growth and cancer prevention. Therefore, strict sun protection procedures to prevent skin cancer may induce the risk of vitamin D deficiency. As there is evidence that the protective effect of less intense solar radiation can outweigh its mutagenic effect, better balanced approaches to sun protection should be sought.

From the bench to emerging new clinical concepts: Our present understanding of the importance of the vitamin D endocrine system (VDES) for skin cancer

It is well accepted that growth and differentiation of keratinocytes and other cell types are regulated by 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)], the active form of vitamin D. Moreover, growing evidence now indicates that the UV-B-mediated cutaneous photosynthesis of vitamin D [and the consecutive cutaneous production of 1,25(OH)(2)D(3))] represents an evolutionary highly-conserved endocrine system that protects the skin against environmental hazards that may promote skin cancerogenesis, including ultraviolet and ionizing radiation. It is the aim of this review to summarize our present understanding of the cutaneous vitamin D endocrine system (VDES) and its importance for the prevention of skin cancerogenesis.

Time trends and latitude dependence of uveal and cutaneous malignant melanoma induced by solar radiation

In order to evaluate the role of solar radiation in uveal melanoma etiology, the time and latitude dependency of the incidence rates of this melanoma type were studied in comparison with those of cutaneous malignant melanoma (CMM). Norway and several other countries with Caucasian populations were included. there is a marked north-south gradient of the incidence rates of CMM in Norway, with three times higher rates in the south than in the north. No such gradient is found for uveal melanoma. Similar findings have been published for CMM in other Caucasian populations, with the exception of Europe as a whole. In most populations the ratios of uveal melanoma incidence rates to those of CMM tend to decrease with increasing CMM rates. This is also true for Europe, in spite of the fact that in this region there is an inverse latitude gradient of CMM, with higher rates in the north than in the south.In Norway the incidence rates of CMM have increased until about 1990 but have been constant or even decreased (for young people) after that time, indicating constant or decreasing sun exposure. The uveal melanoma rates have been increasing after 1990. In most other populations the incidence rates of CMM have been increasing until recently while those of uveal melanoma have been decreasing. These data generally support the assumption that uveal melanomas are not generated by ultraviolet (UV) radiation and that solar UV, via its role in vitamin D photosynthesis, may have a protective effect.

The JUPITER lipid lowering trial and vitamin D: Is there a connection?

There is growing evidence that vitamin D deficiency significantly increases the risk of adverse cardiovascular events and that a vitamin D status representing sufficiency or optimum is protective. Unfortunately, in clinical trials that address interventions for reducing risk of adverse cardiovascular events, vitamin D status is not generally measured. Failure to do this has now assumed greater importance with the report of a study that found rosuvastatin at doses at the level used in a recent large randomized lipid lowering trial (JUPITER) had a large and significant impact on vitamin D levels as measured by the metabolite 25-hydroxyvitamin D. The statin alone appears to have increased this marker such that the participants on average went from deficient to sufficient in two months. The difference in cardiovascular risk between those deficient and sufficient in vitamin D in observational studies was similar to the risk reduction found in JUPITER. Thus it appears that this pleiotropic effect of rosuvastatin may be responsible for part of its unusual effectiveness in reducing the risk of various cardiovascular endpoints found in JUPITER and calls into question the interpretation based only on LDL cholesterol and CRP changes. In addition, vitamin D status is a cardiovascular risk factor which up until now has not been considered in adjusting study results or in multivariate analysis, and even statistical analysis using only baseline values may be inadequate.

Vitamin D as a promising anticancer agent

Presence of vitamin D receptors in noncalcemic tissues and subsequent identification of its involvement in growth factor(s)-mediated cellular function suggested its probable beneficial role in genesis, progression and survival of cancerous growths. Data collected from both in vitro and in vivo studies are highly optimistic regarding its potential in prevention and regression of colorectal, prostate and breast cancers. The vitamin has been found to interfere with the transduction pathways of various growth factor(s)-activated receptors (receptor tyrosine kinases) thereby modulating transcription and alteration of genomic functions resulting in inhibition of cell proliferation and angiogenesis and facilitation of cell differentiation and apoptosis. It also increases the level of an endogenous protein - cystatin D, which possesses antitumor and antimetastatic property, by facilitation of the expression of the gene coding for it. Though not as a primary anticancer agent, this vitamin may be used for the prevention of cancer and included as an adjuvant in combination chemotherapy for the treatment of cancer.

The relationship between serum 25 hydroxy vitamin d levels and asthma in children

Purpose

Asthma and other allergic disorders have increased over the past decades in nearly all nations. Many studies have suggested the role of vitamin D deficiency in both T-helper1 and T-helper2 diseases; however, the association between vitamin D, allergy, and asthma remains uncertain. In this study, the associations of 25-hydroxy vitamin D3 levels with asthma and with the severity of asthma were evaluated.

Methods

This cross-sectional study was conducted on 50 asthmatic children and 50 healthy controls aged 6-18 years. Serum 25-hydroxy vitamin D3 levels were determined and compared between the two groups. The relationship between serum vitamin D levels and pulmonary function test outcomes and eosinophil counts were examined in asthmatic patients.

Results

Univariate analysis of the relationship between asthma and vitamin D showed that decreased vitamin D levels were associated with significantly increased odds of asthmatic state (P=0.002). In a multivariate analysis after adjustment for age, body mass index, and sex, the relationship between vitamin D and asthma increased. In asthmatic patients, 25-hydroxy vitamin D levels had direct and significant correlations with both predicted FEV1 (R²=0.318; P=0.024) and FEV1/FVC (R²=0.315; P=0.026). There were no associations between vitamin D level and eosinophil counts, duration of disease, and the number of hospitalization or unscheduled visits in the previous year (P>0.05).

Conclusions

These results showed that serum 25-hydroxy vitamin D levels were inversely associated with asthma, and there was a direct and significant relationship between vitamin D levels and pulmonary function test outcomes in asthmatic children. An interventional study in asthmatic patients with low serum vitamin D concentration may establish a causal relationship between asthma and vitamin D.

Effect of interval between serum draw and follow-up period on relative risk of cancer incidence with respect to 25-hydroxyvitamin D level: Implications for meta-analyses and setting vitamin D guidelines

Ecological studies have reported strong inverse correlations between indices of solar ultraviolet-B (UVB) doses and incidence and/or mortality rates for many types of cancer. Case-control studies (CCS) generally find inverse correlations between serum 25-hydroxyvitamin D [25(OH)D] concentration measured at time of diagnosis for cancer incidence, whereas nested case-control studies (NCCS), which involve a several-year follow-up time after serum sampling, generally do not. This paper examines the relation between follow-up interval and relative risk (RR) for breast, colorectal, and prostate cancer. I plot the RR versus serum 25(OH)D data as a function of follow-up time from the literature for each type of cancer. For breast cancer, RRs were significantly reduced only for follow-up periods less than 3 years. For colorectal cancer, RRs were generally significantly reduced for follow-up periods up to 12 years. For prostate cancer, RRs were not statistically significant from 4 years to 28 years. This study included no CCS. Follow-up periods after serum sampling should not be too long for breast cancer because once a tumor reaches a diameter of 1-3 mm, it requires angiogenesis to continue growing, and vitamin D reduces angiogenesis around tumors. Breast cancer diagnoses are more common in spring and fall than in summer or winter, indicating that they can grow rapidly if circulating 25(OH)D drops in the fall or melatonin levels drop in spring. Serum sampling should be conducted during the study, perhaps every 2 years, to overcome the problem of change of 25(OH)D concentration during cohort studies.

Vitamin D receptor (VDR) polymorphisms and skin cancer: A systematic review

Skin cancer is the most common cancer in humans. There are several types of skin cancer that include basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and malignant melanoma (MM). The associations of vDr polymorphisms with skin cancer risk are not well characterized so far. Only a few epidemiologic studies have directly addressed the relationship between VDR polymorphisms and the incidence and prognosis of MM. To make the most of the available information on VDR polymorphisms and skin cancer (MM, BCC and SCC), we undertook a systematic review of published studies. In conclusion, data summarized in this review support the concept that the vitamin D endocrine system (VDES) is of importance for pathogenesis and progression of MM and other types of skin cancer.

From the bench to the clinic: New aspects on immunoregulation by vitamin D analogs

The skin is a vital organ that plays a crucial role in defending us from pathogens. Multiple players from the innate and adaptive immune system are involved, such as neutrophils, dendritic cells, lymphocytes and antimicrobial peptides. Chronic inflammatory skin diseases can be mediated by inflammatory T cells and their interactions with other cells in the skin. Vitamin D is generated in the skin upon sun exposure and has a variety of effects. Vitamin D and its analogs have been used with success in treating mild to moderate T cell-mediated skin diseases, but how they mediate the beneficial effects is not well understood. In the recent years, emerging evidence is rising that vitamin D analogs and its modulation on the immune system plays a major role. It has been shown that vitamin D analogs can induce the generation of regulatory T cells, which are able to suppress proliferation and alter the function of inflammatory T cells. This may help explain the therapeutic effects that are observed and at the same time give hope that in combination with other therapy or used alone, vitamin D analogs may be helpful when treating more severe forms of the diseases.

Vitamin D analogs in the treatment of psoriasis: Where are we standing and where will we be going?

Vitamin D and analogs exert in the skin and other tissues potent effects on cellular differentiation and proliferation. Moreover, these compounds regulate apoptosis and exert immunomodulatory effects. During the last decades, it has convincingly been shown that vitamin D compounds are effective and safe in the topical treatment of psoriasis, where they nowadays represent a standard therapy. This review summarizes laboratory and clinical investigations related to the treatment of psoriasis with calcitriol or analogs. Additionally, promising concepts for the development of new vitamin D analogs are discussed. As a matter of fact, the final goal to create strong antiproliferative or antiinflammatory acting vitamin D analogs that exert only minor calcemic activity has not been reached until today. New agents that may activate selective vitamin D signalling pathways but may exert only negligible calcemic activity would declare a new era in dermatologic therapy and may also be effective in the topical or systemic treatment of various inflammatory skin diseases including atopic dermatitis and in various cutaneous malignancies, including lymphomas, squamous cell carcinoma or basal cell carcinoma.

A review of the role of solar ultraviolet-B irradiance and vitamin D in reducing risk of dental caries

Large geographical variations in dental health and tooth loss among US adolescents and young adults have been reported since the mid-1800s. Studies in the 1920s and 1930s noted that vitamin D and ultraviolet-B (UVB) irradiance reduced caries formation, the proposed mechanism being improved calcium absorption and metabolism. This paper reviews the history of studies of dental caries with respect to vitamin D, geographical location and available solar UVB doses. In addition, data on mean dental health rank by state for US servicemen from three periods, 1918, 1934 and 1943, were used in regression analyses with respect to summertime solar UVB doses and an index for mottled enamel, a proxy for natural fluoridation of drinking water, for 1935. There was a significant inverse correlation for dental health rank with respect to solar UVB from doses of 4.0 to 6.5 kJ/m(2) with little change thereafter. Adding data for mottled enamel rates for the states with UvB doses <6.6 kJ/m(2) improved the adjusted R(2) from 0.45 to 0.52. The mechanism whereby UVB reduces risk of dental caries is likely through production of vitamin D, followed by induction of cathelicidin and defensins, which have antimicrobial properties. Serum 25-hydroxyvitamin D concentrations at or above 30-40 ng/ml should significantly reduce the formation of dental caries. It is unfortunate that the UVB and vitamin D findings were not given more consideration in the 1950s as a way to reduce the risk of dental caries when water fluoridation was being proposed.

Vitamin d, and kidney disease

Mineral metabolism abnormalities, such as low 1,25-dihydroxyvitamin D (1,25(OH)(2)D) and elevated parathyroid hormone (PTH), are common at even higher glomerular filtration rate than previously described. Levels of 25-hydroxyvitamin D (25(OH)D) show an inverse correlation with those of intact PTH and phosphorus. Studies of the general population found much higher all-cause and cardiovascular (CV) mortality for patients with lower levels of vitamin D; this finding suggests that low 25(OH)D level is a risk factor and predictive of CV events in patients without chronic kidney disease (CKD). 25(OH)D/1,25(OH)2D becomes deficient with progression of CKD. Additionally, studies of dialysis patients have found an association of vitamin D deficiency with increased mortality. Restoration of the physiology of vitamin D receptor activation should be essential therapy for CKD patients.

Is supplementation of vitamin d beneficial for fracture healing? A short review of the literature

There has been a surge of interest regarding the benefits of vitamin D supplementation to prevent fractures. But can it also make them heal more quickly once they have occurred-that is, is supplementation of vitamin D beneficial for fracture healing? We found 13 studies that met our inclusion criteria, 11 of these were performed in animals. Two animal studies showed negative, 2 neutral, and 7 positive results. One clinical case series in humans was inconclusive in our opinion, and one randomized double-blind placebo-controlled trial showed that supplementation of vitamin D3 and calcium in elderly women with reduced bone mass and a proximal humerus fracture had a positive influence on bone healing. The major weakness of the latter study is low number of participants. A clear statement on the benefits of vitamin D for fracture healing awaits further trials, but all types of fractures in elderly individuals indicate the need for secondary prevention and the implementation of appropriate guidelines concerning falls, vitamin D, and osteoporosis.

Reducing hip fractures in the elderly

Clinical question:

Is there evidence that hip protectors and vitamin D with calcium supplementation reduce hip fractures in the elderly?

Results:

The results are that vitamin D and calcium supplementation reduce incidence of hip fractures. Hip protectors provide some benefit in reducing hip fractures in elderly patients in residential facilities.

Implementation:

Primary care providers should assess patients for the risk of hip fracture and consider using hip protectors and nutritional supplementaton in selected individuals to prevent fractures.

Is vitamin D status a determining factor for metabolic syndrome? A case-control study

This study was undertaken to assess vitamin D status in nonmenopausal women with metabolic syndrome (MeS) and to evaluate its possible role in inflammation and other components of MeS. A case-control study was conducted during late fall and winter 2009-10. A total of 375 women with waist circumference (WC) ≥88 cm were examined to find 100 who met MeS criteria according to the National Cholesterol Education Program (NCEP)/Adult Treatment Panel (ATP) III criteria (NCEP/ATP III). Of those without MeS, 100 age- and residence area-matched women were selected as a control group. Anthropometric and laboratory evaluations were performed. Waist-to-hip ratio (WHR), body mass index (BMI), homeostatic model of insulin resistance (HOMA-IR) and body fat mass (FM) were also evaluated. Women with MeS had significantly higher BMI, waist circumference (WC) and FM but lower serum osteocalcin than controls. There was no significant difference in serum 25 hydroxyvitamin D (25[OH]D), intact parathyroid hormone (iPTH) or vitamin D status between the two groups. Serum highly sensitive C-reactive protein (hsCRP) concentration was significantly higher in the MeS group, compared to the controls (3.4 ± 3.3 vs 2.0 ± 1.9 mg/L, P < 0.001). The difference remained significant even after controlling for BMI (P = 0.011), WC (P = 0.014) and FM (P = 0.005). When comparison was made only in those subjects with insulin resistance (HOMA-IR > 2.4), hsCRP was still higher in the MeS group (n = 79) than in the control group (n = 61) (P < 0.001). When data were categorized according to vitamin D status, in the MeS group significantly higher plasma glucose concentrations were observed in subjects with vitamin D deficiency compared to those with insufficiency or sufficiency (104.0 ± 11.7, 83.0 ± 11.3 and 83.2 ± 9.9 mg/dL, respectively, P < 0.001). Interestingly, their WC or WHR did not show any significant difference. In stepwise regression analysis, 25(OH)D was the main predictor of both hsCRP and plasma glucose. Vitamin D status may, at least in part, be a determining factor of systemic inflammation and the related metabolic derangements of MeS.