Preclinical Report

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In vivo histological evaluation of a novel ablative fractional resurfacing device†

  1. Basil M. Hantash MD, PhD1,2,
  2. Vikramaditya P. Bedi MS2,
  3. Bhumika Kapadia BS2,
  4. Zakia Rahman MD1,2,
  5. Kerrie Jiang NP2,
  6. Heather Tanner MS2,
  7. Kin Foong Chan PhD2,*,
  8. Christopher B. Zachary MBBS, FRCP3

Article first published online: 20 FEB 2007

DOI: 10.1002/lsm.20468

Issue

Lasers in Surgery and Medicine

Lasers in Surgery and Medicine

Special Issue: Dermatologic Laser Surgery

Volume 39, Issue 2, pages 96–107, February 2007

Additional Information

How to Cite

Hantash, B. M., Bedi, V. P., Kapadia, B., Rahman, Z., Jiang, K., Tanner, H., Chan, K. F. and Zachary, C. B. (2007), In vivo histological evaluation of a novel ablative fractional resurfacing device. Lasers Surg. Med., 39: 96–107. doi: 10.1002/lsm.20468

Author Information

  1. 1

    Stanford University School of Medicine, Stanford, California 94305

  2. 2

    Reliant Technologies, Inc., Mountain View, California 94043

  3. 3

    University of California, Irvine, California 92697

*Reliant Technologies, Inc., 464 Ellis Street, Mountain View, CA 94043, USA.

  1. †

    K.F.C. has disclosed a potential financial conflict of interest with this study.

Publication History

  1. Issue published online: 20 FEB 2007
  2. Article first published online: 20 FEB 2007
  3. Manuscript Accepted: 31 OCT 2006

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Keywords:

  • fractional photothermolysis;
  • infrared;
  • lasers;
  • CO2;
  • Er:YAG;
  • collagen;
  • MTZ;
  • MEND;
  • wound healing;
  • heat shock;
  • epithelialization

Abstract

Background and Objectives

A novel carbon dioxide (CO2) laser device employing ablative fractional resurfacing was tested on human skin in vivo for the first time.

Study Design/Materials and Methods

An investigational 30 W, 10.6 µm CO2 laser system was focused to a 1/e2 spot size of 120 µm to generate an array of microscopic treatment zones (MTZ) in human forearm skin. A range of pulse energies between 5 and 40 mJ was tested and lesion dimensions were assessed histologically using hematoxylin & eosin. Wound healing of the MTZ's was assessed immediately-, 2-day, 7-day, 1-month, and 3-month post treatment. The role of heat shock proteins was examined by immunohistochemistry.

Results

The investigational CO2 laser system created a microscopic pattern of ablative and thermal injury in human skin. The epidermis and part of the dermis demonstrated columns of thermal coagulation that surrounded tapering ablative zones lined by a thin eschar layer. Changing the pulse energy from 5 to 30 mJ resulted in a greater than threefold increase in lesion depth and twofold increase in width. Expression of heat shock protein (hsp)72 was detected as early as 2 days post-treatment and diminished significantly by 3 months. In contrast, increased expression of hsp47 was first detected at 7 days and persisted at 3 months post-treatment.

Conclusion

The thermal effects of a novel investigational ablative CO2 laser system utilizing fractional resurfacing were characterized in human forearm skin. We confirmed our previous ex vivo findings and show for the first time in-vivo, that a controlled array of microscopic treatment zones of ablation and coagulation could be deposited in human skin by varying treatment pulse energy. Immunohistochemical studies of heat shock proteins revealed a persistent collagen remodeling response lasting at least 3 months. We successfully demonstrated the first in-vivo use of ablative fractional resurfacing (AFR™) treatment on human skin. Lasers Surg. Med. 39:96–107, 2007. © 2007 Wiley-Liss, Inc.

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