Is enhanced platelet activation the missing link leading to increased cardiovascular risk in psoriasis?

Background: Psoriasis is an immune mediated inflammatory skin disease associated with systemic inflammation resulting in increased risk for associated cardiovascular co-morbidities. The role of platelet activation in the pathophysiology of this condition has not been clearly studied. We undertook to study the platelet activation markers in psoriasis, as compared to controls and to identify its association with disease severity in psoriasis.

Methods: Sixty-two patients with psoriasis and 62 age and gender matched healthy controls were enrolled in this cross-sectional study. The severity of the disease was assessed using the psoriasis area severity index (PASI) scoring. The platelet indices [mean platelet volume (MPV) and platelet distribution width (PDW)] were estimated by an automated haematological laser optical analyzer. Plasma soluble P-selectin and platelet derived microparticle (PDMP) concentrations, serum high sensitivity C-reactive protein (hs-CRP) and interleukin (IL)-6 concentrations were estimated in all study participants. Platelet aggregation was assessed using adenosine diphosphate (ADP) as aggregating agent.

Results: We observed that there was significantly higher platelet indices (MPV and PDW) in patients with psoriasis, when compared to controls. Plasma soluble P-selectin concentrations, PDMP and platelet aggregation were significantly elevated in patients with psoriasis, as compared to controls. We also found significantly higher concentrations of hs-CRP and IL-6 in patients with psoriasis, as compared to controls. Platelet activation and systemic inflammation markers correlated positively with PASI, except PDW. We also observed significant positive correlation between platelet activation and systemic inflammation in psoriasis.

Conclusion: Significant platelet activation and systemic inflammation were observed in patients with psoriasis, especially when associated with severe disease. The increased platelet activation might be the missing link between the persistent inflammation and the development of atherosclerotic plaque leading onto cardiovascular co-morbidities seen associated with psoriasis.