Ph.D. Thesis Defense - Plasma Produced Reactive Oxygen and Nitrogen Species in Angiogenesis
Date: May 26, 2011
Time: 10:00 AM
Location: Curtis Hall, Room: 162
Krishna Priya Arjunan
Advisors: Alisa Morss Clyne, Ph.D., and Kambiz Pourrezaei, Ph.D.
Angiogenesis, the growth of new blood vessels from existing vessels, plays a key role in physiological processes including development, growth, and wound healing. Insufficient angiogenesis contributes to impaired wound healing in diabetic patients and the elderly. Vascularization is also essential for the successful engineering of large, complex tissues and organs in vitro. Although successful tissue fabrication of a few hundred microns has been achieved, tissue engineering is limited by the inability to vascularize constructs to provide nutrients to the tissue core.
Plasma medicine is a rapidly expanding interdisciplinary field combining engineering, physics, biochemistry and life sciences. Plasma, the fourth state of matter, is an ionized gas composed of charged particles (electrons, ions), excited atoms and molecules, radicals, and UV photons. Non-thermal dielectric barrier discharge (DBD) plasma, which primarily produces reactive oxygen species (ROS) has previously been used primarily to sterilize tissue and equipment, coagulate blood, or kill bacteria and cancerous cells. A nitric oxide (NO) producing pin-to-hole spark discharge (PHD) plasma has been reported to sterilize liquids and surfaces, including living tissue.
Low doses of reactive oxygen and nitrogen species (ROS/RNS) contribute to angiogenesis. This study demonstrates the potential of plasma in delivering ROS/RNS into liquids and cells for wound or tissue engineering vascularization. ROS produced by a DBD plasma penetrated into both treatment liquid as well as into endothelial cells. These ROS then enhanced endothelial cell proliferation, migration and tube formation through fibroblast growth factor-2 (FGF-2) release. Specifically, H2O2 and OH· were the primary ROS responsible for plasma-induced angiogenesis. In longer term studies, non-thermal DBD plasma induced FGF-2 release led to secondary intracellular ROS production, enhanced FGF-2 expression and subsequent enhanced FGF-2 release. In a parallel study, a PHD plasma produced NO that enhanced endothelial cell proliferation and migration while maintaining cell viability.
This research improves both our understanding of plasma and ROS/RNS effects on endothelial cells, and may facilitate the development of inexpensive, portable, medical devices for wound treatment. Thus, this dissertation contributes significantly to vascular biology, plasma medicine and health care.
Curtis Hall is located adjacent to the Main Building at the corner of 32nd and Chestnut Streets.