Nonalcoholic fatty liver disease in psoriasis

Abstract

Psoriasis is a chronic, patchy, red, scaly rash affecting around 2% of the population. People with psoriasis, while usually healthy, are more susceptible than others to arthritis, metabolic syndrome (MetS: type 2 diabetes, high blood pressure and obesity) and a liver disorder called non-alcoholic fatty liver disease (NAFLD). NAFLD starts as excess fat deposits in the liver but can progress to inflammation (non-alcoholic steatotic hepatosis NASH), cirrhosis and even liver cancer. This paper from researchers in the US and Italy reviews the links between psoriasis and NAFLD, which is more than twice as common, and more severe, in people with psoriasis than in those without. The risk of NAFLD in psoriasis increases with age and with the severity of the psoriasis, even when methotrexate (an effective medicine for psoriasis, known to cause liver damage) is taken out of the equation. Both conditions show increased levels of inflammatory chemicals produced by fat (adipokines), and decreased levels of an anti-inflammatory adipokine. Adipokines have a role in energy balance, insulin sensitivity, blood pressure, and blood vessel maintenance, as well as inflammation. The liver responds to adipokines by producing hepatokines which can promote MetS and NAFLD. A multistep process involving these and other body chemicals with complicated feedback loops creates an imbalance between liver cell death and regeneration resulting in NAFLD. The inflammatory events in psoriasis feed in to this process. This review emphasises the importance of monitoring general health in psoriasis and raises the possibility that certain anti-inflammatory medications may alleviate both disorders.