Advanced Tissue Sciences Demonstrates Success of Tissue-Engineered Small-Diameter Blood Vessels.

Business Editors & Health/Medical Writers

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LA JOLLA, Calif.--(BW HealthWire)--Oct. 23, 2001

Pre-Clinical Findings Presented at

Biomedical Engineering Society Meeting

Advanced Tissue Sciences, Inc. (NASDAQ: ATIS) presented research at the annual Biomedical Engineering Society Meeting at Duke University in North Carolina supporting the potential of the company's tissue-engineering technology to replace life-threatening damaged blood vessels in the heart, legs or other areas of the body prone to vascular disease.

The study entailed implanting small-diameter tissue-engineered vascular grafts (TEVGs) into canine carotid arteries and monitoring their patency (whether they remained open) for up to 12 weeks. More than 80% of the grafts demonstrated patency at week four, when the first grafts were removed for tissue analysis. All remaining grafts continued to demonstrate patency until either they were removed for analysis or the 12-week endpoint was reached. This 12-week patency is significant because any hyperplasia (cell overgrowth) that would block the grafts would typically occur before week 12.

Histological evaluation of the grafts demonstrated an intact monolayer of endothelial cells and persistence of underlying smooth muscle cells, which is the structure normally found in native blood vessels. These results show that Advanced Tissue Sciences' core tissue-engineering technology has the potential to create viable and functional small-diameter blood vessels.

TEVGs have the potential to treat many life-threatening conditions, the most prevalent of which is coronary artery disease. According to the American Heart Association, over 500,000 coronary artery bypass procedures are performed annually in the U.S. This procedure requires a surgeon to harvest the saphenous vein, which runs through the leg, in order to use it to bypass diseased coronary vessels. TEVGs could potentially be used in place of the saphenous vein, decreasing patient morbidity and ensuring the bypass graft is disease-free. In addition, TEVGs could potentially be used to replace blood vessels in the leg when impaired circulation occurs, which is a common complication of diabetes. TEVGs could also potentially serve as arteriovenous shunts for patients undergoing dialysis.

"In the field of tissue engineering, developing small-diameter blood vessels is considered both extremely difficult and immensely important," said Anthony Ratcliffe, Ph.D., vice president of research and development at Advanced Tissue Sciences. "We are very encouraged by the success of this pre-clinical trial. It is the culmination of several years of research and development efforts leveraging our cell scaffold-based tissue-engineering technology in collaboration with academic leaders of this field at the University of California, San Diego and the University of Arizona."

"Cardiovascular disease is the leading cause of death in the U.S. and imposes significant costs to the health care system," said Gail K. Naughton, Ph.D., president of Advanced Tissue Sciences. "While there's still much research work to be done, this early success in TEVGs, combined with our efforts in other cardiovascular applications, underscores the potential of our core technology to fill pressing unmet clinical needs, and more importantly, to save lives."

Advanced Tissue Sciences is redefining tissue repair and transplantation with human-based products developed and derived from its patented tissue-engineering technology. It is the only company to have gained FDA approval for a tissue-engineered, living dermal substitute that is human-based, mass-produced and frozen for an extended shelf life.

The company's efforts are concentrated in four therapeutic areas where the body cannot heal itself: wound care; aesthetic and reconstructive; cardiovascular; and orthopedic. Four products are currently generating revenue for the company: TransCyte(R), a temporary covering for second and third degree burns; Dermagraft(R), for the treatment of diabetic foot ulcers; tissue-engineered, human-based collagen for wrinkle injections; and NouriCel(TM) for skincare and cosmetic markets. Other products are in clinical or pre-clinical stages.

The company has developed strategic alliances designed to unlock longer term product opportunities. These include two joint ventures with Smith & Nephew, a strategic alliance with Inamed Corporation and a collaboration with Medtronic, Inc. More information on Advanced Tissue Sciences is available at www.advancedtissue.com.

The discussions contained in this press release that are not strictly historical may be "forward-looking" statements which involve risks and uncertainties. No assurances can be given that our products in clinical and preclinical stages will be successful or receive FDA approval, we will be able to successfully commercialize or significantly penetrate the market or obtain adequate reimbursement for our products, we can manufacture commercial quantities of our products at a reasonable cost, or that we can launch our products in indicated timeframes. These and other risks are detailed in publicly available filings with the Securities & Exchange Commission including but without limitation to Advanced Tissue Sciences' Annual Report on Form 10-K for the year ended December 31, 2000 and the company's quarterly reports on Form 10-Q for the quarters ended March 31, 2001 and June 30, 2001. The company undertakes no obligation to release publicly the results of any revision to these forward-looking statements to reflect events or circumstances arising after the date hereof.