Background: The complete removal of port-wine stains has remained challenging. Based on the principle of treating port-wine stains with a dye laser, intravenous injection of artificial red cells (hemoglobin vesicles) immediately before laser treatment might improve the clinical outcome of the therapy. The hemoglobin vesicle injection increases the hemoglobin concentration in microvessels. Photons of dye laser are absorbed by the mixture of red blood cells and this newly added hemoglobin, potentially producing more heat and photocoagulation and, ultimately, necrosis of the endothelial cells effectively.
Methods: To confirm the performance of hemoglobin vesicles as a photosensitizer, the authors compared the absorbance of hemoglobin vesicles and human blood against 595-nm wavelength and the temperature increases that occur following dye laser irradiation. Furthermore, the authors investigated the microvessel transformation induced by the hemoglobin vesicle intravenous injection. Finally, the authors investigated the effect of the hemoglobin vesicle on the vascular destruction of dye laser irradiation with chicken wattle.
Results: Results show that hemoglobin vesicles have the same absorbance as that of human blood. They produce the same level of heat as human blood after laser irradiation. The hemoglobin vesicle intravenous injection caused dilatation of microvessels in animal models. The dye laser with hemoglobin vesicle can destroy the vessel wall effectively in animal models.
Conclusions: Hemoglobin vesicles can function as photosensitizers to destroy the vessel wall. A possible mechanism of pulsed dye laser–resistant port-wine stains is that overly small vessels do not contain sufficient red blood cells. They are therefore poor absorbers/heaters for these lasers. Hemoglobin vesicle combination therapy will improve clinical outcomes of dye laser treatment against such lesions only.
Chiba, Ichihara, Saitama, Hatano, and Kashihara, Japan
From the Department of Plastic, Reconstructive, and Aesthetic Surgery, Chiba University Graduate School of Medicine; Chiba Rosai Hospital; Saitama Children’s Medical Center; the Laboratory of Pathology, Hatano Research Institute, Food and Drug Safety Center; and the Department of Chemistry, Nara Medical University.
Received for publication December 1, 2015; accepted June 21, 2016.
Presented in part at the 26th Annual Symposium of the Japan Laser Therapy Association, in Tokyo, Japan, June 28 through 29, 2014; and the 22nd Annual Symposium of the Society of Blood Substitutes, in Kumamoto, Japan, October 22 through 23, 2015.
Disclosure: Dr. Sakai is a holder of the patents related to the production and utilization of hemoglobin-vesicles. Artificial red cells (hemoglobin-vesicles) were prepared by Hiromi Sakai at the Department of Chemistry, Nara Medical University. The other authors have no financial interests to declare in relation to the content of this article.
Hiromi Sakai, Ph.D.(D.Eng.), Ph.D.(D.Med.Sci.), Department of Chemistry, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521, Japan, firstname.lastname@example.org