The 1450-nm diode laser has been found to be effective for the treatment of inflammatory acne in USA, Europe and
Japan. However, there is no report on its efficacy in Chinese acne vulgaris patients. We conduct this pilot study to
evaluate the efficacy and safety of the 1450-nm diode laser in the treatment of inflammatory facial acne vulgaris in
Chinese patients. Nineteen patients with inflammatory facial acne were treated with the 1450-nm diode laser at 4- to
6-week intervals. Clinical photographs and lesion counts were obtained at baseline and after each treatment. Subjective
evaluation of response to treatment and pain was assessed using a questionnaire. In our study, clinical improvement was
seen in all patients and was generally dramatic. Lesion counts decreased 34% after one treatment (p<0.01), 56% after
two treatments (p<0.01), and 81% after three treatments (p<0.01). However, the treatment-related pain was
comparatively hard to be tolerated in Chinese patitents, and the other main adverse effect was the hyper-pigmentation
after treatments (36.84%, 7/19).
Many lasers have claimed the clinical efficacy on skin rejuvenation. Systematic and comparative studies are needed to compare different laser effects and probe into the mechanism of laser skin rejuvenation. We performed this study to compare collagen remodeling with different laser effects on mice model in vivo. After depilation, the back skin of KM mice was used for the study. The 595nm pulsed dye laser (10ms), 1320nm Nd:YAG laser(350 ?s), 1064nm Q-switched
(5ns) and long-pulsed Nd:YAG(0.3ms) lasers were applied based on optimal tissue reaction fluence test to irradiate one side of the mice back and leave the other side as the control. Then the collagen remodelling was evaluated at 0, 1, 7, 21, 30 and 60 days, with biophysical parameters' measurements, histological and biochemical examination. All lasers applied showed a statistical improvement in skin elasticity, dermal thickness and synthesis of hydroxyproline compared with their own controls. The Q-switched 1064-nm laser resulted in greater improvement of skin elasticity, dermal
thickness, and higher synthesis of hydroxyproline than the other lasers after two months of treatments, while there was no significant difference among the 595nm, 1320nm and long-pulsed 1064nm lasers. Collagen type III increased markedly after the Q-switched 1064-nm laser treatment whereas more collagen type I was elicited by the 1320-nm laser.
The pulsed dye laser (PDL) has a history of producing safe and effective clearance of dermal vascular lesions; however, non-ablative treatments of rhytids with 595nm PDL are seldom studied. The purpose of our research is to evaluate the changes of skin elasticity, histology and the amount of hydroxyproline after 595nm PDL non-ablative rejuvenation and to offer references for effective clinical treatments. Forty KM mice were used for this experiment. Laser parameters were as follows: an energy fluence of 8 to 12J/cm<sup>2</sup>, a pulse duration of 10ms, and a spot size of 7mm with 10% overlap. Skin elasticity was measured using Reviscometer RVM 600. Specimens were sectioned for hematoxylin-eosin and Van-Gieson staining, and dermal thickness was recorded in an ocular micrometer. The amount of hydroxyproline in the dermis was quantified by the biochemical method. No marked side effects such as blister and purpura were noted during laser treatments. New collagen synthesized with an improvement in the organization of collagen fibrils. The 12 J/cm<sup>2</sup> group improved skin elasticity by 31.7%, dermal thickness by 25.3% and the amount of hydroxyproline by 55.9%. There were the good correlations between dermal thickness and the amount of hydroxyproline. Therefore 595nm PDL non-ablative photo-rejuvenation is a safe and effective method for wrinkle reduction. And the energy level of 12 J/cm<sup>2</sup> has the greatest effect in improving skin mechanical properties and accelerating new collagen formation.