Titolo della tesi: Role of biofilm production and skin inflammatory molecules in supporting the growth and persistence of Cutibacterium acnes in acne vulgaris
Summary
Acne vulgaris is a common inflammatory disorder affecting more than 80% of young adolescents. Evidence suggests that Cutibacterium acnes plays a role in the pathogenesis of acne lesions, although the mechanism(s) are, as yet, poorly understood. The study aimed to measure the prevalence of C. acnes in comedogenesis and the progression towards inflamed acne lesions; to analyze the role of C. acnes as well as the impact of biofilm production and in the antibiotic susceptibility of C. acnes isolates; to assess the level of different inflammatory molecules on the skin of acne patients and their role in promoting bacterial growth and persistence. Samples for microbiological analysis were collected from the skin of 10 healthy subjects and the unaffected skin, the comedones, and the papulo-pustular lesions of 15 acne patients. Microbiota analysis showed a significantly higher relative abundance of C. acnes (P < 0.05) in inflammatory (papule and pustule) compared with non-inflammatory (comedones) acne lesions, unaffected skin, and the skin of healthy subjects. All the strains analyzed were able to produce biofilm. Still, the C. acnes strains isolated from acne patients were significantly more efficient in biofilm production than those isolated from the skin of healthy subjects. The level of cutaneous interleukin (IL)-α, and vascular endothelial growth factor (VEGF) were significantly higher (P < 0.05) in the skin of acne patients as compared to control subjects. Additionally, the presence of both IL-1α and VEGF selectively promoted a concentration-dependent increase of C. acnes growth in-vitro.
These findings suggest that C. acnes proliferates in the inflammatory lesions of acne patients. The increased IL-1α and VEGF levels observed in acne patients' skin may play a role in promoting the growth of C. acnes. Biofilm production by C. acnes may contribute to sustaining bacterial adhesion and chronic persistence in acne.