Acne Vulgaris, Body Mass Index, Insulin Resistance and Retinoic Acid Receptor Gamma: AnyRelationship?

Background: Acne vulgaris (AV) is a common chronic inflammatory disease of thepilosebaceous units associated with long-term sequelae and complications. Little isknown about the association of acne with body mass index (BMI). Among retinoicacid receptors (RARs) α, β, and γ, the messenger RNA level of RAR-γ is the mostreadily detectable by Northern blotting in human and mouse skin. This observationsuggests that RAR-γ may play a critical role in the modulation of the therapeuticbenefits of isotretinoin in skin.Objective: The aim of the present study is to investigate the relation between BMIand severity of acne, and to find out if there is a link between BMI and RAR-γ in skintissues of acne patients, and the subsequent supposed effect on therapy response byisotretinoin.Patient and Methods: In this study, 60 acne vulgaris patients were conducted. Theywere classified according to their BMI into 3 subgroups; group I: 12 normal weight,group II: 21 overweight, and group III: 27 obese individuals. Global Acne GradingSystem (GAGS) was calculated for acne severity. Insulin resistance was checked (bymeasuring serum glucose level, insulin level and Homa-IR score) and RAR-γ levelswere evaluated in skin biopsies by ELISA.Results: Serum glucose level, insulin level and Homa-IR score were significantlyhigher in obese patients as compared to both normal weight and overweight ones,while no significant difference was observed between patients of normal weight andoverweight. The RAR-γ level was significantly lower in obese individuals than thosewith normal weight, and it was also significantly lower in overweight than normalweight. There was non-statistically significant difference in RAR-γ levels betweenoverweight and obese individuals. A statistically significant linear negative correlation was noticed between RAR-γlevels and the serum glucose level (r= -0.519, p=0.001), insulin (r= -0.485, p=0.001),Homa-IR (r= -0.485, p=0.001), and BMI (r= -0.470, p=0.001) in all studied subjectscollectively.Conclusion: Tissue levels of RAR-γ were down regulated in acne patients in relationto their BMI. There was no association between BMI and severity of acne in thecurrent study. Larger studies are needed to confirm these findings. Bettercharacterization of role of RAR-γ could constitute a therapeutic avenue to thetreatment of Acne Vulgaris