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Study using low dose photodynamic therapy shows promise in the treatment of cancerous tumors

Changes in the microstructure of tumors induced by low dose Photodynamic therapy opens new possibilities.

By Emilee Green | Apr 04, 2019

LSM-18-0200.R1 - EC - Perentes-croppedWausau, WI (April 4, 2019) – This study reveals the mechanisms whereby low dose Photodynamic Therapy affects the microstructure of vessels. Using co-cultures of pericytes and endothelial cells in vitro, the authors show that low dose photodynamic therapy activates pericytes through Rho, myosin light chain and focal adhesion kinase phosphorylation (MLC‐P, FAK‐P). This leads to cytoskeletal reconfiguration causing pericytes to contract 3D collagen gels more efficiently.

The clinical report of this study, published in Lasers in Surgery and Medicine (LSM),the official journal of the American Society for Laser Medicine and Surgery, Inc. (ASLMS), was selected as Editor’s Choice in the March 2019 issue of LSM.

The study, led by Jean Yannis Perentes is titled “Vasculartargeted low dose photodynamic therapy stabilizes tumor vessels by modulating pericyte contractility”

Following these in vitro observations, Perentes and colleagues confirmed their findings in two in vivo models of malignant pleural mesothelioma. They found that low dose Photodynamic therapy caused MLC-P in pericytes which was associated to enhanced pericyte coverage of endothelial cells. This change in microstructure of the vasculature was associated to a drop in tumor interstitial fluid pressure and an enhancement of macromolecule distribution in tumors.

“The modulation of the tumor microenvironment to enhance the distribution and impact of chemotherapy is a promising modality for the management of solid tumors. Our study was performed on mesothelioma xenografts but the field of application could be enhanced to any tumor on which light can be delivered (skin, gut, ears/nose/throat, etc).” said Perentes.

Dr. Jean Yannis Perentes is currently a staff surgeon in Thoracic Surgery at the University Hospital of Lausanne. His lab has recently moved to the prestigious Agora structure which combines researchers from the University Hospital, UNIL and UNIGE faculties as well as the Federal Institute in Engineering of Lausanne.

Editor’s Choice is an exclusive article published in LSM, the official journal of the ASLMS. View the complete manuscript.

The American Society for Laser Medicine and Surgery, Inc. (ASLMS) is the largest multi-disciplinary professional organization, dedicated to the development and application of lasers and related technology for health care applications. ASLMS promotes excellence in patient care by advancing biomedical application of lasers and other related technologies worldwide. ASLMS membership includes physicians and surgeons representing multiple specialties, physicists involved in product development, biomedical engineers, biologists, nurses, industry representatives and manufacturers. For more information, visit

The American Society for Laser Medicine and Surgery is the world’s largest scientific organization dedicated to promoting research, education and high standards of clinical care in the field of medical laser applications. It provides a forum for the exchange of scientific information and participation in communicating the latest developments in laser medicine and surgery to clinicians, research investigators, government and regulatory agencies, and the public.

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