Effects of non-invasive, 1,210 nm laser exposure on adipose tissue

Abstract

Background and Objectives

Laser radiation (1,210 nm) has been previously shown to be capable of selective photothermolysis of adipose tissue in vitro when applied non-invasively. The objective of this pilot study was to evaluate the in vivo effects of this laser in human subjects. Study Design/Materials and Methods

Twenty-four adult subjects were exposed non-invasively on the abdomen to a 1,210 nm laser at fluences of 70, 80, and 90 J/cm2, with a 10 mm spot size, 5 seconds pre-cooling, and 3 seconds exposure duration delivered with parallel contact cooling. There was an impairment of the skin-cooling device during the study. Exposure and control sites were biopsied at either 1–3 days or 4–7 weeks. Tissue was processed for nitroblue tetrazolium chloride (NBTC) staining, a marker for thermal damage, and hematoxylin and eosin (H&E) staining. Results

Laser exposures were painful, requiring local anesthesia in most subjects, but otherwise well tolerated. At 1–3 days after exposure, there was a fluence-dependent loss of NBTC staining in the fat and dermis. In 2 of 14 subjects (2 of 42 exposure sites) evaluated at 1–3 days after exposure, epidermal damage was noted within a small portion of the test site, likely due to impaired contact cooling. At 4–7 weeks, lipomembranous changes of the fat were seen in 89% of test sites and 33% of control sites. Conclusions

This in vivo study shows histologic evidence of laser-induced damage of fat. With further development, this might become a useful treatment for disorders involving the fat and/or lower dermis. Lasers Surg. Med. 41:401–407, 2009. © 2009 Wiley-Liss, Inc.