Differential Effects of Western and High-fat Diets on the Acceleration of Psoriatic Inflammation

Diet-induced metabolic changes can aggravate psoriatic inflammation.This study investigated the distinct inflammatory effects induced by a high-fat diet (HFD) and Western diet (WD) in mice by inducing psoriatic inflammation using topical imiquimod following 12 weeks on either diet.Both diets resulted in increased body weight and perigonadal fat mass compared to a chow diet, with HFD-fed mice gaining more weight.Fasting glucose levels were significantly elevated only in the HFD group.During psoriatic inflammation, WD-fed mice exhibited more pronounced weight loss and aggravated clinical signs of psoriasis.Systemic inflammatory responses, indicated by spleen weight and soluble CD14 serum levels, were increased in both HFD-and WD-fed mice compared to the chow-fed group, with no significant difference between the two diet groups.However, localized inflammatory responses in skin lesions were more pronounced in WDfed mice, with increased expression of inflammatory mediators.The intestinal immune environment and microbiome composition showed no significant differences between the diet groups.Transcriptomic analysis of skin lesions identified differentially expressed genes, with WD-fed mice enriched in gene sets related to inflammation, keratinization, and cornified envelope formation.In contrast, HFD-fed mice were enriched in genes related to tissue microenvironment remodeling.These findings suggest that WD exacerbates psoriatic skin inflammation more than HFD by promoting inflammatory responses in the skin, highlighting dietspecific impacts on localized inflammation.