Platelet function may aid in determining disease severity for patients with psoriasis who are at an increased risk of developing cardiovascular disease (CVD) and increased inflammation, a review notes.
A review indicated that indexes of abnormal platelet function may help diagnosis disease severity in patients with psoriasis in order to prevent worsening conditions, which can lead to cardiovascular disease and increased inflammation.
Platelets initiate and regulate immune and inflammatory processes and can malfunction in several different ways. Platelets are major players in homeostasis and thrombosis but if they are dysfunctional, they can can play a role in the development of cardiovascular disease, affecting patient quality of life, psychological burden, and impaired social functioning, the researchers wrote.
Overall, investigators suggested that more progress must be made in antipsoriasis treatments in order to decrease the incidence of platelet-related complications. But despite an abundance of evidence pointing to increased risk of cardiovascular disease, there are no current anti-platelet guidelines for primary prevention in patients with psoriasis.
The Dangers of Platelet-Induced Thrombosis
Platelet aggregation induced by thrombin, adenosine diphosphate (a molecular compound used in metabolism and muscle contraction), and the antibiotic ristocetin is enhanced in patients with psoriasis, which can increase risk for blood clots.
Platelet-derived microparticles (PDMPs) are also elevated in patients with psoriasis compared with healthy individuals, especially in those with severe cases.
“Elevated levels of PDMPs observed in [patients with psoriasis] may be conducive to the development of thrombus and predictive of the cardiovascular outcomes by triggering a cascade of events,” investigators said.
PDMP incubation can cause an increase in microparticles associated with thrombosis, platelet aggregation, and endothelial wall damage.
Studies have shown PDMP levels can significantly decrease in patients treated with anti-tumor necrosis factor-α agents, such as etanercept, infliximab, and adalimumab, in concordance with topical therapies.
However, whether these psoriasis treatments can reduce cardiovascular risks by decreasing PDMP production still needs further study.
Platelet Involvement in Psoriatic Inflammation
Additionally, an increased mean platelet volume (MPV) can be an indicator of larger, more reactive platelets and is often elevated in patients with psoriasis and psoriatic arthritis.
Increased MPV values may also be relevant to increased inflammation and are dramatically higher in patients with psoriasis who also have atherosclerosis and metabolic syndrome, suggesting that MPV could be an early predictor to diagnose premature atherosclerosis and sensitivity in psoriasis.
P-selectin (CD62p) is a specific marker of irreversible platelet activation and in high amounts can increase risk of atherosclerosis in patients with psoriasis.
Evidence from previous studies have found that “effective therapy such as narrowband phototherapy and biological drugs could significantly reduce the level of CD62P and control platelet activation in patients who had increased CD62P expression when untreated,” investigators noted.
Platelet and white blood cell interaction is increased in patients with psoriasis. Some studies have reported that increased platelet activation may favor platelet interaction with white blood cells, which can cause vascular complication by creating plaque in the blood vessel.
This plaque can promote extravasation of white blood cells from the blood vessels close to the skin to cause inflammation of the skin.
The platelet to white blood cell ratio (PLR) is significantly higher in patients with psoriasis and psoriatic arthritis. PLR has been found to decrease after treatment with different biologics.
“It is very critical to find the relevant mechanism about platelet activation and to target platelet-specific pathways to slow down the progress of psoriasis,” investigators said.
The Risks of Oxidative Stress for Psoriasis
Oxidative stress is a key factor in the pathogenesis of psoriasis and represents the imbalance between the reactive oxygen species (ROS) production and the antioxidant system.
ROS production, especially in the creation of nitric oxide (NO), can cause damage to cellular constituents and may lead to the formation of lipid oxidation products such as malondialdehyde, which correlate with psoriasis disease severity.
Investigators noted that, “although ROS could regulate platelet function by different pathways, it remains to be further studied whether there is a corresponding mechanism that oxidative stress state in psoriasis could induce platelet activation and thereby increase the cardiovascular complication risks.”
Fan Z, Wang L, Jiang H, Lin Y, Wang Z. Platelet dysfunction and its role in the pathogenesis of psoriasis. Dermatology. 2020;2(236)1-10. doi: 10.1159/000505536.