In vitro and in vivo photosensitizing capabilities of 5-ALA versus photofrin in vascular endothelial cells.
OBJECTIVE
The objective of the present study was to evaluate the feasibility of photodynamic therapy (PDT) for complicated hemangiomas. The photosensitizing activities of 5-aminolevulinic acid (5-ALA) and Photofrin were evaluated in vitro with human dermal microvascular endothelial cells (MEC) and in vivo with the chicken cox comb.


METHODS
The in vitro absorption and photosensitizing activities of 5-ALA and Photofrin were examined in a MEC culture system. The percentages of MEC killed by different drug concentrations at a wavelength of 630 nm were measured by either live/dead or lactate dehydrogenase-released assays. Similarly, the in vivo biological activities of 5-ALA and Photofrin exposed to different total light dosages at 630 nm were studied by determining the amount of necrosis produced in chicken combs.


RESULTS
MEC incubated with 5-ALA at a concentration of 35 microg/ml and exposed to laser light at 630 nm at a power density of 100 mW/cm2 showed a 50% cell kill. MEC incubated with Photofrin at a concentration of 3.5 microg/ml and exposed to laser light at 630 nm at a power density of 100 mW/cm2 showed a 50% cell kill. Chicken combs that received 200 mg/kg of 5-ALA exposed to laser light at 630 nm at a power density of 100 mW/cm2 had an injury depth of 362.5+/-27.6 microm at histologic examination. Combs exposed to a power density of 100 or 120 mW/cm2 showed injury depths of 732.5+/-29.1 and 792.5+/-36.0 microm, respectively. Chicken combs that received 2.5 mg/kg of Photofrin exposed to laser light at 630 nm at a power density of 80 mW/cm2 had an injury depth of 535.6+/-22.3 microm at histologic examination. Combs exposed to a power density of 100 or 120 mW/cm2 showed injury depths of 795.8+/-32.5 and 805.2+/-49.1 microm, respectively.


CONCLUSIONS
Both 5-ALA and Photofrin have the capability to destroy MEC in vitro and vasculature in vivo. However, Photofrin achieved a higher degree of cell kill and tissue destruction at lower drug concentrations and at lower power densities.
Chang
C J
CJ
Chang Gung Memorial Hospital, Chang Gung Medical College, Taipei, Taiwan.
Sun
C H
CH
Liaw
L H
LH
Berns
M W
MW
Nelson
J S
JS
D000622:Aminolevulinic Acid / Q000494:pharmacology*; D000818:Animals; D002645:Chickens; D017323:Dihematoporphyrin Ether / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000648:ultrastructure; D006391:Hemangioma / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D007834:Lasers; D008856:Microscopy, Fluorescence; D009336:Necrosis; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology*; D012867:Skin / Q000098:blood supply; D012878:Skin Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D014407:Tumor Cells, Cultured
D017319:Photosensitizing Agents; D000622:Aminolevulinic Acid; D017323:Dihematoporphyrin Ether; D007770:L-Lactate Dehydrogenase