The Wellman Laboratories of Photomedicine at the Massachusetts General Hospital in
Boston is an internationally known institute for the development and application of laser in medicinco
Besides fundamental research which investigates the interaction of light with cells and molecules,
a great deal of studies arc performed towards clinical application to treat human diseases.
For this reason, all known medical specialties are involved in research programmes examining the
use of laser for their purposes: from ophtalmologists, using photodynamic therapy to treat
choroidal neovascularization, oncologists to photochemically target and remove breast cancer
cells from bone marrow, urologist to detect bladder cancer with fluorescence, gastroenterologists
to treat Barret's oesophagus to dermatologists removing latloes and treating multiple skin diseases
with the laser. The application of laser to treat vascular diseases was started decades ago, but more
recently the concept of photodynamic therapy was introduced by the research group of Dr.
LaMuraglia to prevent restenosis. As a research fellow in surgery I joined this group in 1994 and
our research goal was to better understand how photodynamic therapy affects the vascular wall.
The results from these investigations are presented in tllis thesis. The first part gives an outline of
the problem of restenosis, the concept of photodynamic therapy and aims of the study. The following
chapters describe how photodynamic therapy interacts with biological factors that regulate
the vascular healing process. Finally, considerations for possible clinical use are discussed