Serum concentrations of 25-OH vitamin D and the pro-inflammatory interleukins IL-17, IL-23, and IL-18 in patients with plaque psoriasis

AIMS

The present study aimed to assess vitamin D status and serum concentrations of pro-inflammatory cytokines IL-17, Il-23, and IL-18 in patients with chronic plaque psoriasis and their association with various demographic and clinical characteristics.

METHODS

The study was conducted during the autumn/winter period on 48 patients with chronic plaque psoriasis and 48 controls. Total serum 25(OH)D level was determined with Roche Elecsys® 2010 Vitamin D total assay. Commercial ELISA kits were used for quantifying the serum levels of IL-17A, IL-18, and IL-23.

RESULTS

Serum 25(OH)D had a median value of 16.95 ng/mL (IQR 10.8-23.50) for patients with psoriasis and 18.80 ng/mL (IQR 15.45-25.85) for the control group (P=0.09). A moderate negative correlation was found between PASI score and 25(OH)D levels (rs=-0.34; P=0.02). The serum levels of IL-17 (P=0.001), IL-23 (P=0.01) and IL-18 (P=0.02) were significantly higher in the patient group compared to controls. IL-17 concentrations were higher in patients with moderate to severe psoriasis compared to patients with mild psoriasis (P=0.003). No significant correlations were detected between the serum concentrations of 25(ОH)D and IL-17, IL-23, and IL-18.

CONCLUSION

It was confirmed that IL-17 serum level is associated with psoriasis severity. Measurement of 25(OH)D serum concentration can be useful in patients with moderate to severe psoriasis with or without comorbidities. A direct association between 25(OH)D serum concentration and the serum concentrations of IL-17, IL-23, or IL-18 was not identified in this study.

Low Vitamin K Status in Patients with Psoriasis Vulgaris: A Pilot Study

Psoriasis vulgaris (PV) is a disease characterized by skin manifestations and systemic inflammation. There are no published studies to date on vitamin K status assessed by extrahepatic vitamin K-dependent proteins [e.g., osteocalcin (OC) and matrix Gla protein (MGP)] in patients with PV, even if vitamin K was found to promote wound contraction and decrease the healing time of the skin. Metabolic syndrome (MS), a comorbidity of PV, was found to influence vitamin K status, and vitamin D was found to be involved in the pathogenesis of PV. Therefore, our aim was to assess the status of vitamins K and D in subjects with PV. We enrolled 44 patients with PV and 44 age- and sex-matched subjects as a control group (CG), of which individuals with MS were designated the CG with MS subgroup. Furthermore, the PV patients were stratified into two subgroups: those with MS (n = 20) and those without MS (n = 24). In addition to the quantification of vitamin D and MGP in all subjects, the uncarboxylated OC/carboxylated OC (ucOC/cOC) ratio was also assessed as an inversely proportional marker of vitamin K status. We found an increased ucOC/cOC ratio in the PV group compared to CG but also a greater ucOC/cOC ratio in the PV with MS subgroup than in the CG with MS subgroup. MGP was decreased in the PV with MS subgroup compared to CG with MS subgroup. There was no difference in the vitamin D concentration between the groups. This is the first study to report decreased vitamin K status in patients with PV, independent of the presence of MS.

Efficacy and safety of vitamin D supplementation on psoriasis: A systematic review and meta-analysis

OBJECTIVES

Our aim was to analyze the results of published randomized controlled trials (RCTs) on vitamin D supplementation for psoriasis in order to explore its effectiveness and safety.

PATIENTS AND METHODS

As of July 7 2023, we conducted a systematic literature search in PubMed, Cochrane, Embase, and Web of Science Core Collection databases. The study outcomes included change values in Psoriasis Area and Severity Index (PASI) (at 3 months, 6 months, and end of follow-up)/Dermatology Life Quality Index (DLQI)/Psoriasis disability index (PDI)/C-reactive protein (CRP), and adverse events.

RESULTS

333 patients from 4 studies were evaluated. Pooled analyses showed no significant effect of DLQI/PDI/CRP change value (P > 0.05) or PASI change value (3 months, end of follow-up; P > 0.05). Sensitivity analyses and statistical tests did not support the results of the PASI change values (6 months, P = 0.05). However, the results of subgroup analyses should not be ignored(supplementation with vitamin D2 or Asia would be more effective; P = 0.03). There were no serious adverse effects, and only a few individuals experienced nausea.

CONCLUSIONS

The efficacy and safety of vitamin D supplementation in the treatment of psoriasis remains unremarkable. The search for a new prognostic index that combines clinical and laboratory factors is needed to compensate for the shortcomings of existing measures and provide stronger evidence of validity.

The CDX2 G allele and the FoKI F allele of the VDR gene are more prevalent and related to changes in vitamin D levels in patients with psoriasis vulgaris: A pilot study

BACKGROUND AND AIMS

Psoriasis is a chronic, non-contagious autoimmune condition marked by dry, itchy,erythematous and scaly plaques. From modest, localized plaques to total body coverage, the severity of psoriasis varies. Plaque, guttate, inverted, pustular, and erythrodermic psoriasis are the five primary kinds. About 90% of cases are of plaque psoriasis, commonly known as psoriasis vulgaris. Study aims to determine the impact of an rs2228570 (FokI) variant and an rs11568820 (CDX2) variant on serum vitamin D levels (SVD) in patients with psoriasis, and the correlation between the two variants and disease severity.

METHODS

A case-control study consisting of 95 psoriasis vulgaris patients and 84 healthy controls. The clinical investigation, molecular genetics analysis, and biochemical analysis were done for both groups.

RESULTS

SVD levels were significantly decreased in psoriasis patients group. FokI genotypes analysis, we found no significant variance between groups. CDX2 G/G genotype is more prevalent in patients than controls. Moderate psoriasis vulgaris patients with CDX2 G/G genotypes have higher SVD levels than CDX2 G/A, and CDX2 A/A p = 0.003.

CONCLUSION

The study found a difference in vitamin D levels between patients and healthy subjects, as well as a difference in vitamin D levels with different FoKI and CDX2 genotypes.

Psoriasis and Vitamin D: A Systematic Review and Meta-Analysis

Psoriasis is a chronic immune-dysregulated inflammatory disease and hypovitaminosis D is considered a risk factor. We conducted an online database search to review and meta-analyze the relationship between vitamin D, other bone metabolism parameters, and psoriasis. The efficacy of oral vitamin D supplementation in improving Psoriasis Area and Severity Index (PASI) was also evaluated. Non-original articles, case reports, and animal studies were excluded. Bias risk was assessed according to the Cochrane Collaboration's tool and the Newcastle-Ottawa scale in randomized controlled trials (RCTs) and case-control studies, respectively. Unstandardized mean differences were used for data synthesis. Twenty-three studies reported serum 25 hydroxyvitamin D (25(OH)D) levels in 1876 psoriasis patients and 7532 controls. Psoriasis patients had significantly lower 25(OH)D levels than controls (21.0 ± 8.3 vs. 27.3 ± 9.8, p < 0.00001). Conversely, 450 psoriasis patients had lower levels of parathormone than 417 controls (38.7 ± 12.8 vs. 43.7 ± 16.5, p = 0.015). Four RCTs examined the effect of oral vitamin D supplementation on psoriasis for 173 patients and 160 patients were treated with placebo. No significant differences were found in PASI after 3, 6, and 12 months of supplementation. It is shown that 25(OH)D serum levels are significantly lower in psoriasis, but, although the granularity of RCT methodology may have influenced the pooled analysis, vitamin D supplementation did not seem to improve clinical manifestations.

The vitamin D receptor gene polymorphism rs1544410 T/T genotype as a predictor of factor vitamin D thresholds deficiency in patients with psoriasis vulgaris-A preliminary study

BACKGROUND

Many clinical features of psoriasis include a rash with itchy, scaly patches, most frequently on the knees, elbows, trunk, and scalp. By studying genes involved with psoriasis receptivity, the pathologic pathways of psoriasis become clearer and more understood.

AIM

To predict the participation of rs1544410 in serum vitamin D levels (SDL) in psoriasis, psoriasis susceptibility, and severity.

PATIENTS/METHODS

One hundred five patients with psoriasis were categorized by body surface area as mild, moderate, and severe. SDL and genetic analysis of rs1544410 were performed using polymerase chain reaction and standard Sanger methods.

RESULT

Our findings revealed that SDL were higher in healthy subjects than in patients. The rs1544410 genotype TT was more prevalent in patients, while CT was more prevalent in controls. Our findings revealed that the T alleles were frequently more in the patient group than in the controls. (p ≤ 0.001). While in healthy normal individuals, the C alleles were frequently more (p ≤ 0.001). SDL are lower in patients with the TT genotype. Patients with moderate form of psoriasis have higher SDL than those with mild or severe form.

CONCLUSION

rs1544410 polymorphism has been linked to a higher probability of psoriasis and SDL deficiency. However, grander scale studies in a larger number of people are necessary.

Comparing Vitamin D Level Between Patients with Psoriasis and Healthy Individuals: A Systematic Review and Meta-Analysis

BACKGROUND

Psoriasis is nowadays regarded as a systemic inflammatory disorder. Among the topicals, vitamin D derivates are often applied on the skin for their anti-inflammatory and immune-modulatory properties. Vitamin D serum levels in psoriasis (PsO) patients are still debated and an eventual depletion may offer the rational to integrate anti-psoriatic therapies with oral vitamin D. Then, we aimed to perform a systematic review and meta-analysis on the current evidence towards serum vitamin D level in PsO.

METHODS

We searched in PubMed, Scopus, Web of Sciences, ScienceDirect and Science Information Database (SID) using the terms "Vitamin D" and "Psoriasis" including manuscripts in English, Italian and Persian. Duplications were excluded using EndNote software and records were screened by title, abstract and full-text. Quality assessment of studies was assessed using Newcastle Ottawa Checklist (NOS). Psoriasis odds ratio (OR) and mean serum vitamin D levels were calculated and displayed in Forest-plots. Heterogeneity indexes were evaluated using I2 and Q. Sensitivity analysis and publication biases were also considered.

RESULTS

From 3006 records extracted, after removing duplicates and analyzing full texts we finally included 19 manuscripts involving a total of 1387 PsO cases and 6939 controls. PsO patients exhibited a substantial odds ratio (3.07, 95% CI: 1.56-6.04) for lower serum vitamin D levels compared to the control group. Standardized Mean Difference (SMD) of vitamin D in PsO versus controls was -0.92 (-1.33 to -0.51).

CONCLUSION

Psoriatic patients displayed higher risk to have a vitamin D deficiency. Interventional studies to verify the preventive value are mandatory.

Vitamin D status in Psoriasis: impact and clinical correlations

Psoriasis is a continuing, periodic, immune‑mediated, fiery skin disease branded by hyper proliferation of epidermal keratinocytes and accompanying with inflammatory cellular infiltrate in both dermis and epidermis. Immunomodulation could be an important effect of vitamin D in Psoriasis. This case-control study was designed to measure serum 25-hydroxy vitamin D levels in patients with psoriasis and healthy controls and to find out clinical correlation, if any. Six hundred two (n = 602) subjects (285 cases and 317 controls) were taken for the study. Cases and controls were frequency matched with respect to age and gender. Various demographic and clinical details were taken using a questionnaire. Chemiluminescence Micro Particle Immunoassay was used to estimate serum 25-hydroxy vitamin D levels. The vitamin D deficiency in psoriasis patients was 60.0% vs. 17.5% in controls (P < 0.001) with mean vitamin D levels of 28.3 ± 13.9 ng/ml in psoriasis patient’s vs. 37.9 ± 9.7 ng/ml in controls. Vitamin D deficiency was found to be associated with psoriasis independently of gender, age, smoking status, family history, hypertension, chronic medication, nail changes, duration of symptoms and severity of disease. Vitamin D levels were seven times lower in patients with Psoriasis as compared to controls. Reduced vitamin D levels are related to duration and clinical severity of the disease. Early detection of vitamin D deficiency and timely intervention could lead to better clinical outcome and improved quality of life in psoriasis patients.

Vitamin D Signaling in Psoriasis: Pathogenesis and Therapy

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

Association of rs1544410 and rs7975232 Polymorphisms and Serum Vitamin D Levels with Psoriasis Susceptibility and Severity: A Case-Control Study in Egyptian Patients

Background

Vitamin D is a regulatory factor for skin immune functions through vitamin D receptor, which is expressed on many immune cells. Vitamin D receptor is located on chromosome 12q 13.11 and has many single nucleotide polymorphisms. Some of them were hypothesized to be associated with psoriasis. Psoriasis is a genetic disease that is greatly affected by environmental factors.

Methods

A total of 135 psoriasis patients and 114 healthy controls were recruited. Both had a measurement of serum vitamin D and two vitamin D receptor variants:, rs1544410: G > A (HGVS:NC_000012.12:g.47846052) and rs7975232: C > A (HGVS: NC_000012.12:g.47845054). We assessed the relationship between vitamin deficiency as well as the two gene polymorphisms with psoriasis susceptibility and severity.

Results

Serum vitamin D levels were not significantly different between cases and controls. However, a significant association between vitamin D levels and severity was observed. We attributed this to our finding that rs7975232 was more significantly polymorphic among cases than controls, while rs1544410 polymorphism did not show a significant difference among the 2 groups.

Conclusion

We did not find a significant difference in serum vitamin D levels between cases and controls. Yet, psoriasis severity was significantly associated with serum vitamin D levels. We attributed this to other findings that the vitamin D receptor rs7975232 gene is polymorphic in psoriasis patients. At the same time, rs1544410 was not significantly more polymorphic in psoriasis patients. Both genes’ polymorphisms were associated with severe psoriasis.

Is vitamin D status relevant to psoriasis and psoriatic arthritis? A retrospective cross-sectional study

BACKGROUND

Psoriasis is a systemic, immune-mediated disease characterized by inflammatory manifestations in the skin and joints. Vitamin D deficiency is currently considered a pandemic and is associated with comorbidities including psoriasis and psoriatic arthritis (PsA).

OBJECTIVES

To determine the prevalence of hypovitaminosis D [25(OH)D] in patients with plaque psoriasis, with and without PsA, and of independent predictors of serum 25(OH)D levels.

DESIGN AND SETTING

Retrospective cross-sectional study conducted among 300 patients at an outpatient clinic in a university center in Juiz de Fora, Minas Gerais, Brazil.

METHODS

Demographic and clinical data (psoriasis area and severity index [PASI], family history, age at onset, disease duration, and the presence of PsA according to Classification Criteria for Psoriatic Arthritis), skin phototype, and season of the year were reviewed.

RESULTS

Hypovitaminosis D (< 30 ng/mL) was highly prevalent in patients with psoriasis with and without PsA (82.2% and 74.9%, respectively). An inverse correlation between PASI and vitamin D was found (without PsA r = -0.59 and, PsA r = -0.52, P < 0.001), and multivariate regression revealed that hypovitaminosis D was associated with disease severity, season, and phototype. It was confirmed by binary logistic regression between PASI and vitamin D deficiency (< 30 ng/mL), (odds ratio, OR 1.78 CI: -0.20-0.53, P < 0.001).

CONCLUSION

Hypovitaminosis D (< 30 ng/mL) was highly prevalent in psoriatic patients with and without PsA. Season and skin phototype were associated with 25(OH)D levels. An inverse association between PASI and serum 25(OH)D levels was established.

The Effects of Vitamin D on the Expression of IL-33 and Its Receptor ST2 in Skin Cells; Potential Implication for Psoriasis

Interleukin 33 (IL-33) belongs to the IL-1 family and is produced constitutively by epithelial and endothelial cells of various organs, such as the skin. It takes part in the maintenance of tissue homeostasis, repair, and immune response, including activation of Th2 lymphocytes. Its involvement in pathogenesis of several inflammatory diseases including psoriasis was also suggested, but this is not fully understood. The aim of the study was to investigate expression of IL-33 and its receptor, ST2, in psoriasis, and the effects of the active form of vitamin D (1,25(OH)₂D₃) on their expression in skin cells. Here we examined mRNA and protein profiles of IL-33 and ST2 in 18 psoriatic patients and healthy volunteers by qPCR and immunostaining techniques. Potential effects of 1,25(OH)₂D₃ and its receptor (VDR) on the expression of IL-33 and ST2 were tested in cultured keratinocytes, melanocytes, fibroblasts, and basal cell carcinoma cells. It was shown that 1,25(OH)₂D₃ effectively stimulated expression of IL-33 and its receptor ST2’s mRNAs in a time-dependent manner, in keratinocytes and to the lesser extends in melanocytes, but not in fibroblasts. Furthermore, the effect of vitamin D on expression of IL-33 and ST2 was VDR-dependent. Finally, we demonstrated that the expression of mRNA for IL-33 was mainly elevated in the psoriatic skin but not in its margin. Interestingly, ST2 mRNA was downregulated in psoriatic lesion compared to both marginal tissue as well as healthy skin. Our data indicated that vitamin D can modulate IL-33 signaling, opening up new perspectives for our understanding of the mechanism of vitamin D action in psoriasis therapy.

Influence of Ethnicities and Skin Color Variations in Different Populations: A Review

BACKGROUND

In the world scientific tradition, skin color is the primary physical characteristic used to divide humans into groups. Human skin has a wide range of tones and colors, which can be seen in a wide range of demographic populations. Many factors influence the color of people's skin, but the pigment melanin is by far the most important. Melanin is produced by cells called melanocytes in the skin and is the primary determinant of skin color in people with darker skin. Indeed, >150 genes have now been identified as having a direct or indirect effect on skin color. Vitamin D has recently been discovered to regulate cellular proliferation and differentiation in a variety of tissues, including the skin. The mechanisms through which the active vitamin D metabolite 1,25 dihydroxyvitamin D3 (or calcitriol) affects keratinocyte development are numerous and overlap with the mechanisms by which calcium influences keratinocyte differentiation. Ultraviolet (UV) is the most major modifiable risk factor for skin cancer and many other environmental-influenced skin disorders when it is abundant in the environment. Although the UV component of sunlight is known to cause skin damage, few researches have looked at the impact of non-UV solar radiation on skin physiology in terms of inflammation, and there is less information on the role of visible light in pigmentation.

SUMMARY

The quantity and quality of melanin are regulating by the expression of genes. The enzyme tyrosinase is primarily responsible for the genetic mechanism that controls human skin color. Genetics determines constitutive skin color, which is reinforced by facultative melanogenesis and tanning reactions. High quantities of melanin and melanogenic substances are typically accepted in darker skin to protect against UV radiation-induced molecular damage. Previous research has proposed that skin color variation is caused by a dynamic genetic mechanism, contributing to our understanding of how population demographic history and natural selection shape human genetic and phenotypic diversity. However, the most significant ethnic skin color difference is determined by melanin content. This current review aimed to assess the influence of skin color variations in skin structure and functions as well as difference in dermatological disease patterns. Also, this article reviewed several cases of skin color adaptation in different populations. Key Messages: Skin color impacts the composition and activity. Therefore, the contrast of dermatological ailments between distinct race-related categories is remarkable. Skin color adaptation is a challenging procedure. Refinement of skin color is an age-old craving of humans with ever-evolving drifts.

Pilot study: immunohistochemistry expressions of vitamin D receptor associated with severity of disease in psoriasis patients

BACKGROUND

Psoriasis is a chronic inflammatory skin disorder characterized by keratinocyte hyperproliferation, differentiation abnormalities, and resistance to apoptosis. There are several factors that can affect psoriasis and vitamin D is one of the recently arisen. The role of vitamin D is mediated by vitamin D receptors (VDR) in target cells. VDR is a nuclear hormone that is involved in the antiproliferation and pro-differentiation pathways in keratinocytes. However, until now vitamin D/VDR signaling in psoriasis has not been fully understood.

METHODS

A cross-sectional study that involved 28 skin specimens from psoriasis patients to assess the immunohistochemistry expressions of VDR as well as their association with severity and duration of psoriasis. Statistical analyses were performed using Spearman's correlation coefficients, with P <0.05 was considered statistically significant.

RESULTS

In total, 28 specimens from psoriasis patients consisting of 60.7% women and 39.3% men, with mean age 41.28 ± 14.97 years, predominantly age group 46-55 years (25%), mean duration of disease 6.64 ± 4.26 years, and mean Psoriasis Area and Severity Index (PASI) score 19.23 ± 11.30. The immunohistochemistry expressions of VDR were predominantly strong (57.1%) and located in the basal layer (53.6%). There were a significant negative correlation between the expressions of VDR and PASI score (P <0.001, r = -0.719) and between the expressions of VDR and duration of disease in psoriasis (P = 0.020, r = -0.438).

CONCLUSION

VDR expressions and severity of psoriasis showed a strong significant negative correlation and also a moderate significant negative correlation between VDR expressions and duration of disease.

The Association Between Vitamin D Values and Psoriasis: A Literature Review

The Vitamin D deficiency could be involved in the development of psoriasis, Vitamin D defficiency being considerd to be involved in the development of disorders related to cellular immune system. The aim of this study is to review the literature in order to find if there is an association between the Vitamin D level in the serum and psoriasis. A search for relevant articles was performed using PubMed, Web of Science and Springer databases. A total of 19 articles fulfilled the criteria for inclusion in this review. 14 studies revealed statistically significant lower levels of Vitamin D in psoriatic patients when compared to healthy controls. The other 5 studies did not found a statistically significant difference between 25-hydroxycholecalciferol levels in psoriasis group and in control group.

Low Vitamin D in Psoriasis: Reality or Myth?

Context:

Psoriasis is a chronic, systemic disease with the beneficial effect of topical vitamin D3 analogs, known for a long time. Low levels of vitamin D are increasingly found to be associated with the initial development of some autoimmune diseases. There are contradictory reports of low serum levels of vitamin D3 in the pathogenesis of psoriasis.

Aims:

(1) To determine the serum levels of vitamin D, calcium and C-reactive protein (CRP) in patients with psoriasis vulgaris, (2) To compare these levels with the serum levels of controls, and (3) To correlate them with the severity of the disease.

Subjects and Methods:

A hospital-based case–control study with 61 patients of psoriasis and 61 age- and sex-matched controls was undertaken. A detailed history was taken and examination including body mass index, Psoriasis Area and Severity Index (PASI) was done. Estimations of serum vitamin D, serum calcium, and CRP levels were done.

Results:

Mean 25(OH) vitamin D level was not significantly different between persons with and without psoriasis. Mean vitamin D level in cases was 18.41±9.41 and that in controls was 17.24±13.03 (P =0.63). However, vitamin D level were significantly lower in females than in males in both cases (P =0.02) and controls (P =0.006). There was no significant correlation between the severity of psoriasis and serum levels of vitamin D, serum calcium, and CRP.

Conclusions:

Serum level of vitamin D did not correlate with the severity of psoriasis in our study.

Association between psoriasis and vitamin D: Duration of disease correlates with decreased vitamin D serum levels: An observational case-control study

Recent literature has focused on the association of psoriasis with lower than normal or highly deficient vitamin D blood levels.To investigate the controversial association between psoriasis and vitamin D levels.From 2012 to 2014, 561 subjects were assessed, of which 170 had psoriasis, 51 had an autoimmune bullous, and 340 were healthy patients. Anagraphical data, 25(OH)D blood levels, and seasons of vitamin D levels assessments were recorded for each group.Vitamin D levels were significantly different among the 3 groups (K = 151.284; P = .0001). Psoriatic patients had significantly lower serum levels of 25(OH)D (21.8 ng/mL) than healthy controls (34.3 ng/mL) (chi-square = 11.5; P = .0007). Patients with bullous diseases showed the lowest vitamin D mean values (18.2 ng/mL). The linear multiple regression model showed 25(OH)D levels to be influenced by age, season of blood vitamin D levels assessment, and psoriasis duration.These results confirm the reduced vitamin D levels in psoriatic patients when compared to healthy controls, and provide new evidence regarding the association of vitamin D levels and psoriasis duration. The limits of our study include its observational nature and the small number of patients undergoing biological immunosuppressive therapies.

Role of Vitamin D Beyond the Skeletal Function: A Review of the Molecular and Clinical Studies

The classical function of Vitamin D, which involves mineral balance and skeletal maintenance, has been known for many years. With the discovery of vitamin D receptors in various tissues, several other biological functions of vitamin D are increasingly recognized and its role in many human diseases like cancer, diabetes, hypertension, cardiovascular, and autoimmune and dermatological diseases is being extensively explored. The non-classical function of vitamin D involves regulation of cellular proliferation, differentiation, apoptosis, and innate and adaptive immunity. In this review, we discuss and summarize the latest findings on the non-classical functions of vitamin D at the cellular/molecular level and its role in complex human diseases.

Association between circulating 25-hydroxyvitamin D levels and psoriasis, and correlation with disease severity: a meta-analysis

BACKGROUND

Psoriasis is a chronic, autoimmune, inflammatory skin disorder. 25-hydroxy vitamin D [25(OH)D] deficiency may contribute to the pathogenesis of psoriasis through reduction in antiproliferative, anti-inflammatory and antiangiogenic activities.

AIM

To evaluate the relationship between circulating 25(OH)D levels and psoriasis, and to determine the correlation between serum/plasma 25(OH)D levels and psoriasis severity.

METHODS

We performed a meta-analysis to compare serum/plasma 25(OH)D levels between patients with psoriasis and healthy controls (HCs), and to determine the correlation coefficients between circulating 25(OH)D levels and psoriasis severity as assessed by Psoriasis Area and Severity Index (PASI).

RESULTS

Ten articles with a total of 571 patients with psoriasis and 496 HCs were included. The 25(OH)D level was significantly lower in the psoriasis group than in the HC group. Subgroup analysis by sample size revealed a significantly lower level of 25(OH)D in the psoriasis group for large (N > 80) but not for small (N < 80) sample sizes. Stratification by adjustment for age and/or sex or sample type revealed a significantly lower 25(OH)D level in the psoriasis group after adjustment for serum but not after nonadjustment for plasma. Meta-analysis of the correlation coefficients revealed a small but statistically significant positive correlation between circulating 25(OH)D levels and PASI.

CONCLUSIONS

This meta-analysis demonstrated that circulating 25(OH)D levels are lower in patients with psoriasis, and that a small but statistically significant negative correlation exists between 25(OH)D levels and psoriasis severity.

Th17 micro-milieu regulates NLRP1-dependent caspase-5 activity in skin autoinflammation

IL-1β is a potent player in cutaneous inflammation and central for the development of a Th17 micro-milieu in autoinflammatory diseases including psoriasis. Its production is controlled at the transcriptional level and by subsequent posttranslational processing via inflammatory caspases. In this study, we detected inflammatory caspase-5 active in epidermal keratinocytes and in psoriatic skin lesions. Further, interferon-γ and interleukin-17A synergistically induced caspase-5 expression in cultured keratinocytes, which was dependent on the antimicrobial peptide psoriasin (S100A7). However, diseases-relevant triggers for caspase-5 activity and IL-1β production remain unknown. Recently, extranuclear DNA has been identified as danger-signals abundant in the psoriatic epidermis. Here, we could demonstrate that cytosolic double-stranded (ds) DNA transfected into keratinocytes triggered the activation of caspase-5 and the release of IL-1β. Further, interleukin-17A promoted caspase-5 function via facilitation of the NLRP1-inflammasome. Anti-inflammatory vitamin D interfered with the IL-1β release and suppressed caspase-5 in keratinocytes and in psoriatic skin lesions. Our data link the disease-intrinsic danger signals psoriasin (S100A7) and dsDNA for NLPR1-dependent caspase-5 activity in psoriasis providing potential therapeutic targets in Th17-mediated skin autoinflammation.