Adaptation of the Human Skin by Chronic Solar-simulating UV Irradiation Prevents Ultraviolet-B Irradiation-induced Rise in Serum C–Reactive Protein Levels¶

Validation of a novel method of ultraviolet-induced cutaneous inflammation and its associations with anhedonia

Affective immunology of the skin is a growing area; however, established protocols for measuring individual differences in cutaneous inflammation are lacking. To address this, we present a preliminary validation of Precision Implementation of Minimal Erythema Dose (PI-MED) testing as a method for measuring cutaneous inflammation. PI-MED is a recently adapted protocol, optimized for reproducibility and individual differences research, that uses ultraviolet (UV) light to evoke cutaneous erythema, or inflammatory skin reddening. PI-MED's novel UV dosage schedule produces standardized erythema responses across different skin pigmentation types and shows strong internal consistency within person and good test-retest reliability across 8-10 weeks. In line with predictions, increased PI-MED erythema was associated with heightened anhedonia, across several measures, beyond influences of non-affective covariates. While future work should further refine the dosage schedule for the lightest and darkest skin types, overall, evidence supports PI-MED as a protocol for inducing and measuring individual differences in cutaneous inflammation. Further, PI-MED-induced erythema can expand psychoneuroimmunology research by offering a complementary assessment for general inflammatory tone. This work adds to a growing body of evidence demonstrating a distinct relationship between inflammation and anhedonia.

Solar UVR and Variations in Systemic Immune and Inflammation Markers

The characterization of the effects of solar UVR on a broad set of circulating markers in systemic immunity and inflammation may provide insight into the mechanisms responsible for the UVR associations observed for several benign and malignant diseases. We examined the associations between exposure to solar UVR and circulating levels of 78 markers among 1,819 individuals aged 55–74 years who participated in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial using multiplex assays. Solar UVR was derived by linking the geocoded locations of 10 screening centers across the continental United States and the date of blood draw to the National Solar Radiation Database from 1993 to 2005. We assessed associations between ambient solar UVR and dichotomized marker levels using adjusted weighted logistic regression models and applied a 5% false discovery rate criterion to P-values. UVR exposure was associated (P < 0.05) with 9 of the 78 markers. CCL27, CCL4, FGF2, GM-CSF, IFN-γ, soluble IL4R, IL-7, and IL-11 levels were lower with increasing UVR tertile, with adjusted ORs ranging from 0.66 to 0.80, and the significant association for CCL27 withstood multiple comparison correction. In contrast, CRP levels were elevated with increasing UVR. Solar UVR was associated with alterations in systemic immune and inflammation marker levels.

Ultraviolet radiation, vitamin D and the development of obesity, metabolic syndrome and type-2 diabetes

Obesity is increasing in prevalence in many countries around the world. Its causes have been traditionally ascribed to a model where energy intake exceeds energy consumption. Reduced energy output in the form of exercise is associated with less sun exposure as many of these activities occur outdoors. This review explores the potential for ultraviolet radiation (UVR), derived from sun exposure, to affect the development of obesity and two of its metabolic co-morbidities, type-2 diabetes and metabolic syndrome. We here discuss the potential benefits (or otherwise) of exposure to UVR based on evidence from pre-clinical, human epidemiological and clinical studies and explore and compare the potential role of UVR-induced mediators, including vitamin D and nitric oxide. Overall, emerging findings suggest a protective role for UVR and sun exposure in reducing the development of obesity and cardiometabolic dysfunction, but more epidemiological and clinical research is required that focuses on measuring the direct associations and effects of exposure to UVR in humans.

Accumulation of C-reactive protein in basal keratinocytes of normal skins

BACKGROUND

C-reactive protein (CRP) is a prototypic acute phase protein which increases dramatically in the blood during the first 48h of tissue inflammation and has been recognized as a risk factor for atherosclerosis. CRP interacts with a variety of proteins.

OBJECTIVE

To know the role of accumulated CRP in the skin.

METHODS

Interaction of CRP with basal keratinocytes was studied using immunohistochemical method and keratinocyte culture system.

RESULTS

We found an immunohistochemical deposition of CRP on the basal keratinocyte membrane in some normal human skins (23 out of 46 skins). When added to cultured keratinocytes, heat-denatured but not native CRP was found to adhere to keratinocyte cell membrane after 1h, then internalized into cytoplasm after 24h. The heat-denatured CRP recognized at least four keratinocyte polypeptides with the molecular weights of 56, 42, 32 and 24kDa. Ligand binding assays suggested that multiple populations of receptor-ligand interactions were involved in the binding between CRP and keratinocyte. Cultured dermal microvascular endothelial cells were found to express CRP of which expression was greatly induced by interleukin-1β (IL-1β) treatment, suggesting that the deposited CRP in the basal keratinocytes can be derived from local dermal microvasculatures as well as from systemic circulation (serum). Treatment of cultured keratinocytes with heat-denatured CRP induced interleukin-8 (IL-8) expression, a potent leukocyte chemotactic cytokine. CRP in the medium (liquid phase) and CRP-coated dishes (solid phase) both inhibited the adhesion of keratinocytes in culture.

CONCLUSION

Accumulation of CRP may regulate the skin inflammation and keratinocyte proliferation by modulating keratinocyte cytokine expression and adhesion to substrate.

Evaluation of systemic oxidant/antioxidant status and paraoxonase 1 enzyme activities in psoriatic patients treated by narrow band ultraviolet B phototherapy

OBJECTIVES

Ultraviolet B is a potent oxidative stress (OS) inducer in the skin; however, there are no data about the systemic oxidative effect of narrow band ultraviolet B (NB-UVB) phototherapy. In this study, we aimed to investigate the change in the OS status of psoriatic patients who were treated by NB-UVB phototherapy and to determine the relationships between OS, psoriasis severity, and systemic inflammatory condition.

METHODS

Twenty-four psoriatic patients were treated with a total of 30 sessions of NB-UVB irradiation. Psoriasis area and severity index (PASI), serum levels of high sensitive C-reactive protein (hsCRP), total antioxidant status (TAS), total oxidant status (TOS), the oxidative stress index (OSI), serum paraoxonase (PON), and arylesterase (ARE) activities before and after NB-UVB therapy were determined.

RESULTS

PASI scores significantly decreased after NB-UVB therapy (P = 0.001). The pre- and post-treatment hsCRP and TAS levels were similar (P = 0.253 and 0.301, respectively). TOS and OSI values significantly increased after phototherapy (both P < 0.001). PON and ARE activities did not change after treatment (both P > 0.05). There was no correlation between PASI and hsCRP, TAS, TOS, OSI, PON, and ARE values (P > 0.05).

CONCLUSION

A systemic OS may emerge in psoriatic patients treated by NB-UVB phototherapy.

C-reactive protein and seizures in focal epilepsy: a video-electroencephalographic study

PURPOSE

  C-reactive protein (CRP) has been studied extensively in many noninflammatory neurologic conditions, but there has been little study of CRP in the context of seizures or epilepsy. The purpose of this study was to examine CRP concentrations in patients with refractory focal epilepsy who were undergoing video-electroencephalography (EEG) monitoring compared with healthy controls, and CRP change during 24 h after a seizure.

METHODS

  CRP levels were measured in serum at the onset of video-EEG recording (CRP-0h) and at 3, 6, 12, and 24 h after index seizure (the first verified localized-onset seizure) in 31 patients during inpatient video-EEG monitoring by using high sensitivity measurement of CRP concentration. The patients were categorized into two groups: temporal lobe epilepsy (TLE; n = 15) and extratemporal lobe epilepsy (XLE; n = 16). Eighty healthy volunteers served as controls.

KEY FINDINGS

  CRP-0h concentration was significantly higher in patients with refractory focal epilepsy than in controls (3.5 vs. 0.7 mg/ml, p < 0.001). All five patients with elevated CRP-0h (>mean + 2 standard deviations in controls) had TLE (vs. none in XLE; p = 0.018). Index seizure type was associated with CRP increase from baseline to maximum level after index seizure (p = 0.005). The most important predictor of increase in CRP level was secondarily generalized tonic-clonic seizure (SGTCS; p = 0.030).

SIGNIFICANCE

  The higher baseline levels in patients with epilepsy compared with healthy controls demonstrates that CRP concentrations are also affected in refractory epilepsy. Our data suggest that SGTCS stimulates CRP production. These results emphasize the association between inflammation and refractory epilepsy.

Long-term UVB irradiation affects the immune functions of carp (Cyprinus carpio) and rainbow trout (Oncorhynchus mykiss)

The effects of long-term, low-dose ultraviolet B (UVB) radiation on immune functions of two fish species representing different taxonomic groups, carp (Cyprinus carpio) and rainbow trout (Oncorhynchus mykiss), were assessed in this study. The fish were exposed to 7, 20 or 60 mJ cm(-2) UVB three times per week, for 6 weeks. In carp, UVB exposure affected the respiratory burst activity of blood and head kidney phagocytes, differential blood leukocyte counts and blood chemistry. Phytohemagglutinin (PHA)-stimulated in vitro proliferation responses of blood and head kidney lymphocytes, however, remained unchanged. Rainbow trout tolerated the irradiations with fewer alterations, but significant changes were detected in blood chemistry and hematocrits of the irradiated fish. These results indicate that long-term exposure to low doses of UVB induces immunomodulation in fish, and that there are species-specific differences in sensitivity to irradiation.