Increase in circulating sphingosine-1-phosphate and decrease in ceramide levels in psoriatic patients

Psoriasis is characterized by hyperproliferation, deregulated differentiation and impaired apoptosis of keratinocytes. Mechanisms of lipid profile disturbances and metabolic syndrome in the psoriatic patients are still not fully understood. Sphingolipids, namely ceramides (CER) and sphingosine-1-phosphate (S1P) are signal molecules which can regulate cell growth, apoptosis and immune reactions. The aim of the study was to evaluate circulating CER and S1P levels in plaque-type psoriasis and their associations with the disease activity, inflammatory or metabolic markers and the presence of psoriatic comorbidities. Eighty-five patients with exacerbated plaque-type psoriasis and thirty-two healthy controls were enrolled. Serum CER and S1P concentrations before the treatment were examined. General patient characteristics included: PASI (Psoriasis Area and Severity Index), BMI (Body Mass Index), inflammatory and biochemical markers, lipid profile and presence of psoriatic comorbidities. Total serum concentration of CER was significantly decreased (p = 0.02) and concomitantly S1P levels significantly increased (p = 0.002) in psoriatic patients compared to the healthy control group. Among patients with psoriasis no significant correlations with the disease activity and inflammation markers were observed and only patients with psoriatic arthritis had significantly higher CER total concentration. Serum sphingolipid disturbances in psoriatic patients were observed. Decreased total CER and increased S1P serum levels may reflect their epidermal altered composition and metabolism. Patients with psoriatic arthritis have higher CER levels than psoriasis with skin involvement only. It might provide additional predictive value for psoriatic arthritis and may convey higher risk of metabolic and cardiovascular disease development in this group of patients.