Precursor Cells Generated From Human Embryonic Stem Cells Show Ability to Repair Vascular Damage in Animals
-New, scalable population of hemangioblast cells halves the death rate following heart attack and repairs ischemic limbs and damaged vasculature-
Alameda, CA, May 7, 2007 - Today, Advanced Cell Technology (OTCBB: ACTC) announces what it considers to be the biggest scientific news in its history, the ability to produce hemangioblast cells, literally in the billions, for potential use in a wide variety of clinical applications. This finding is documented in a paper being published today in Nature Methods, the premier science journal from the same publisher as Nature.

In the paper, ACTC reports that for the first time hemangioblast precursor cells derived from human embryonic stem (hES) cells can be used to achieve vascular repair. The research, which appears today online (ahead of print), by ACTC and its collaborators, describes an efficient method for generating large numbers of bipotential progenitors-known as hemangioblasts-from hES cells that are capable of differentiating into blood vessels as well as into all blood and immune cell lineages.

Hemangioblasts are the mythical "unicorn" cells in the human embryo that give rise to our entire blood and immune system, as well as to the blood vessels in our body. Previous attempts to both produce large numbers of hemangioblasts and to induce them to develop into multiple types of blood cells (hematopoetic lineages) and blood vessel cells (endothelial lineages) have not produced sufficient numbers of cells to allow potential therapeutic applications. Moreover, these hemangioblasts could be frozen (cryopreserved), thawed, and expanded into large cell populations with the same character and function as blood and endothelial cells.

ACTC now has the ability to generate an unlimited supply, literally billions, of these cells, for potential use in a wide variety of clinical applications.

In animal tests, the cells have shown impressive reparative potential. When injected into the bloodstream of mice with damaged retinas, they migrated to the other side of the body and repaired the damaged vasculature within a few days.

Additionally, in animals which suffered from massive heart attacks, the cells reduced mortality rates by 50%, as described below.

"The ability to repair vascular damage using these cells could have a profound impact on a large number of diseases that are major human afflictions," said Robert Lanza, M.D., Vice President of Research & Scientific Development at ACTC, and senior author of the study. "Our results suggest the possibility of using nature's early cellular developmental components to restore vascularization and function in patients with vascular disease. An injection of these cells may be able to prevent a patient from having a leg amputated or a patient from dying after a heart attack."

"We have developed for the first time a simple and highly scalable source of human hemangioblasts," stated Shi-Jiang Lu, Ph.D., Director of Differentiation at ACTC and first author of the paper. "These proprietary cells represent a new and distinctly different population of cells that can be differentiated into vascular structures and multiple hematopoietic cell types. The elimination of serum and other animal components from the system, as well as the ability to generate an unlimited supply of these cells, will be important for future preclinical and human studies."

When the cells were injected into animals that had damage to their retina due to diabetes or ischemia-reperfusion injury (lack of adequate blood flow) of the retina, the cells homed to the site of injury and showed robust reparative function of the entire damaged vasculature within 24-48 hours. The cells showed a similar regenerative capacity in animal models of both myocardial infarction (50% reduction in mortality rate) and hind limb ischemia, with restoration of blood flow to near normal levels.
"These cells were able to generate functional blood vessels in the presence of severe tissue injury as well as in chronic disease states," says Maria Grant, M.D., Professor of Pharmacology at the University of Florida, and an author on the paper. "These cells have a robust vascular reparative ability under what is typically considered very adverse growth conditions making them potentially ideal for treatment of diabetic vascular complications where profound tissue compromise exists and healing is typically severely compromised."

"While the cells in this study were tested in animal models, we believe this breakthrough has the potential to benefit many Americans suffering from vascular disease," stated William M. Caldwell, IV, Chairman and CEO of ACTC. "Advanced Cell is committed to moving this technology from the laboratory into the clinic. We plan on filing an Investigational New Drug Application with the Food and Drug Administration for the first clinical application of these cells by the end of next year."

The researchers of the paper from ACTC collaborated with scientists from the University of Florida, Gainesville, Florida, and the Memorial Sloan-Kettering Cancer Center (MSKCC), New York, New York. The paper's other authors are Qiang Feng of ACT, Sergio Caballero of the University of Florida, and Yu Chen and Malcolm A.S. Moore, DPhil, of MSKCC.

In August of last year Nature, a premier science journal, published research by ACTC that demonstrated a technique to generate human embryonic stem cells without destroying the embryo-a significant breakthrough in the ethical debate surrounding stem cell research, that made headlines worldwide.