Studies on the mechanism of photodynamic-therapy-induced tumor destruction

Victor H. Fingar; Thomas Jeffery Wieman M.D.

doi:10.1117/12.17661

1 July 1990 Studies on the mechanism of photodynamic-therapy-induced tumor destruction

Victor H. Fingar, Thomas Jeffery Wieman M.D.

Proceedings Volume 1203, Photodynamic Therapy: Mechanisms II; (1990) https://doi.org/10.1117/12.17661
Event: OE/LASE '90, 1990, Los Angeles, CA, United States

Abstract

There exists little doubt that profound changes occur to both tumor and normal tissue microvasculature during photodynamic therapy, and that these changes are important in the process of tumor destruction. We hypothesize that singlet oxygen, produced during light activation of photosensitizer, interacts with cellular membranes and induces the release of arachidonic acid metabolites, notably thromboxane, into the intravascular environment. This leads to vasoconstriction, platelet aggregation, and hemostasis. To test this hypothesis, we have measured the release of thromboxane into serum as a function of porphyrin and light doses used in phototherapy. Sprague Dawley rats bearing chondrosarcoma in the right hind limb were injected with 0-25 mg/kg Photofrin IP'. A catheter was implanted in the carotid artery 24 h later, and the hind limb exposed to 0-135 J/cm2 630 nm light. Immediately after treatment, serum was collected and thromboxane levels were measured by radioimmunoassay. We found significant increases in systemic thromboxane concentrations following phototherapy at the highest porphyrin and light doses, compared to drug and light controls. The administration of indomethacin (10 mg/kg i.p.) prior to treatment suppressed the release of thromboxane from tumor and normal tissues and inhibited hemostasis and tumor response to phototherapy. These studies have reinforced the important role of arachidonic acid metabolites in producing vascular damage during phototherapy.

Citation Download Citation

Victor H. Fingar and Thomas Jeffery Wieman M.D. "Studies on the mechanism of photodynamic-therapy-induced tumor destruction", Proc. SPIE 1203, Photodynamic Therapy: Mechanisms II, (1 July 1990); https://doi.org/10.1117/12.17661

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available