A highly decreased binding of cyclic adenosine monophosphate to protein kinase A in erythrocyte membranes is specific for active psoriasis

Erythroid disturbances before and after treatment of Portuguese psoriasis vulgaris patients: a cross-sectional and longitudinal study

BACKGROUND

A few studies in psoriasis vulgaris patients have reported changes suggesting red blood cell (RBC) damage is linked to neutrophil activation, oxidative stress, and psoriasis worsening.

OBJECTIVE

The aim of this study was to evaluate erythroid disturbances in Portuguese psoriasis vulgaris patients, before, during, and after treatment.

METHODS

A cross-sectional study (n = 73 patients vs 40 healthy control subjects) followed by a longitudinal study (n = 47 patients) was performed, with assessments before, and at 3, 6, and 12 weeks of therapy (10 patients started topical treatment, 17 narrow-band UVB, and 20 photochemotherapy [psoralen plus UVA; PUVA]). Evaluations included hematologic data, total bilirubin levels, membrane-bound hemoglobin (MBH), membrane protein band 3 profile, total plasma antioxidant status (TAS), lipid peroxidation (thiobarbituric acid [TBA] assay), elastase, lactoferrin, and C-reactive protein (CRP).

RESULTS

Before treatment, patients presented with higher leukocyte/neutrophil and reticulocyte counts, elastase, lactoferrin, TBA, TBA/TAS, reticulocyte production index, total bilirubin and MBH values, lower RBC and hematocrit, higher percentages of high-molecular-weight aggregates, and lower percentages of band 3 monomer. After treatment, we observed a reversal in most of the parameters. However, patients still presented with values suggestive of accelerated RBC damage, removal, and production, as most of the parameters were still higher than those in the control group; the same occurred with CRP.

CONCLUSION

Our data suggest that psoriasis vulgaris triggers an inflammatory response, with release of acute-phase reactants, reactive oxygen species, cationic proteins, and proteases, leading to enhanced RBC damage/aging and, ultimately, to enhanced RBC removal. These assumptions were strengthened by the observation that, with treatment, all of these changes were reversed, the inflammation was reduced, the production of reticulocytes was increased, and the RBCs presented changes usually observed in younger/less damaged RBCs. These erythroid changes were enhanced with PUVA therapy, probably due to the more pronounced clearing of the lesions, as suggested by Psoriasis Area and Severity Index (PASI) scores. Finally, after treatment, a residual inflammation still persisted that might contribute to the observed erythroid disturbances.

Soluble adenylyl cyclase defines a nuclear cAMP microdomain in keratinocyte hyperproliferative skin diseases

Cyclic adenosine monophosphate (cAMP) is a nearly ubiquitous signaling molecule important for numerous signaling pathways in human skin. We studied a novel class of mammalian adenylyl cyclase, the soluble adenylyl cyclase (sAC). We examined sAC localization in normal human skin and found it to be present in keratinocytes, melanocytes, mononuclear cells, eccrine ducts, and nerves. In normal skin, sAC keratinocyte staining was evenly distributed throughout the cell. However, in certain hyperproliferative disorders of the skin, including psoriasis, verruca vulgaris, and SCCIS on sun-damaged skin, sAC keratinocyte staining was predominantly nuclear. In contrast, in other hyperproliferative disorders, such as basal cell carcinoma, sAC staining was similar to normal human skin. Using a model of epithelial differentiation, we established that sAC migrates into the nucleus when differentiated cells are induced to reenter the cell cycle. Previous work had determined that nuclear sAC activates the cAMP-response-element-binding (CREB) transcription factor, and we found that in psoriasis lesions, nuclear sAC occurs concomitantly with activation of CREB. Hence, sAC may play a role in the pathogenesis of certain hyperproliferative skin disorders via modulation of gene expression.