NEW ORLEANS—Nonablative laser therapy for acne doesn’t kill Propionibacterium aches or decrease sebum production but instead appears to work by inducing a rapid and dramatic increase in transforming growth factor beta, Edward Seaton, M.D., and colleagues said in a poster presented at the annual meeting of the American Academy of Dermatology.
“TGF-[beta] is very important anti-inflammatory cytokine that plays a pivotal role in decreasing inflammation and is the first stimulus of neocollagenesis,” Dr. Seaton of Hammersmith Hospital, London, said in an interview. “This is the first time a biologic explanation of lasers’ effect on acne has been proposed.”
Dr. Seaton used nonablative laser therapy on the foreheads of 19 subjects with mild to moderate acne who had received no previous treatment. He took before and after measurements of P. acnes colony count, sebum production, and several cytokines and receptors: interleukin-1 (comedogenic), interleukin-1 receptor antagonist (anticomedogenic), interleukin-10 (anti-inflammatory), tumor necrosis factor (proinflammatory), TGF-[beta] (anti-inflammatory), and melanocortin-1 receptor (expressed in healthy sebaceous glands).
Each subject received one session of nonablative laser therapy (wavelength 585 nm, pulse duration 350 msec, 2 J/[cm.sup.2], spot diameter 7 mm). Cytokine levels were obtained from 4-mm punch biopsies from the buttocks before laser treatment and 3 and 24 hours post treatment.
After 24 hours, there was no decrease in the number of P. acnes colonies on the treated area; in fact, there was a non–statistically significant increase in the number of colonies. There was no significant decrease in the sebum excretion rate at 2, 4, 8, or 24 weeks post treatment.
After 24 hours, there was a fivefold increase in TGF-[beta] but no significant changes in any other cytokine or receptor levels. The TGF-[beta] levels had increased slightly, but nonsignificantly, by 3 hours post therapy.
Sullivan, Michele G.
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