Method to manufacture cartilage from human embryonic stem cells

BioTime, Inc. (NYSE Amex: BTX) and its wholly owned subsidiary OrthoCyte Corporation reported today a means of manufacturing cartilage from human embryonic stem cells that is suited for industrial scale-up of a product for the treatment of osteoarthritis. The paper, published online (ahead of print) in the peer-reviewed journal Regenerative Medicine, characterizes a progenitor cell line produced from human embryonic stem (hES) cells using proprietary ACTCellerate™ technology. The study reports that the cells are capable of regenerating cartilage with long sought-after identification markers. The study also shows that the cells can be directly expanded on a scale needed for industrial manufacture, which will be necessary in order to make transplantable cells available in commercial quantities.

“We see osteoarthritis as one of the low-hanging fruits in regenerative medicine”

In today's publication, BioTime scientists reported on one ACTCellerate™ line designated 4D20.8. This proprietary cell line is the cellular component of OrthoCyte's product in development, OTX-CP07. The scientific publication demonstrates that 4D20.8 cells possess site-specific markers of craniofacial mesenchyme, in particular, markers of proximal mandibular mesenchyme. This tissue is of significance in that it naturally produces one of the strongest joint cartilages of the body. The study documented conditions in which the cells can be propagated on a large scale, conditions in which the cells can be differentiated into cartilage in the laboratory, and evidence that the cells could repair damage to knee joints in rat models.

Another significant finding reported in the study is that the OrthoCyte 4D20.8 cells lacked certain mesenchymal stem cell (MSC) markers. MSCs have the ability to proliferate in response to fractures to generate a transient type of cartilage called "hypertrophic cartilage" that functions as a temporary repair of the fracture. Over time, that hypertrophic cartilage is transformed into bone. Therefore, due to their propensity to hypertrophy, MSCs have not served as an effective source of definitive cartilage for joint repair. When compared to MSCs in studies published in the current paper, 4D20.8 cells displayed markers consistent with definitive cartilage progenitors and showed a marked decrease in the expression of hypertrophic chondrocyte markers.

"We see osteoarthritis as one of the low-hanging fruits in regenerative medicine," said Michael D. West, Ph.D., BioTime's Chief Executive Officer. "The rapid rise of this market due to the aging of the baby boom population, the current lack of a cure for the disease, and the ease of scaling our product have led to our prioritizing this product for development."

Arnold Caplan, Ph.D., OrthoCyte's Chief Scientific Officer and Director of the Skeletal Research Center at Case Western Reserve University, commented, "The long-stated goal in orthopedic research has been to isolate the progenitors to specific and diverse types of cartilage in the body, such as those of the ear, nose, trachea, sternum, and weight-bearing joints. Cloning progenitors derived from hES cells is a novel method of obtaining these cells, which will be of great interest to those in the research community and those seeking to cure the debilitating disease of osteoarthritis."

A discussion of OrthoCyte's product development strategy delivered by Dr. Caplan and comments on the implications of BioTime's scientific advances are available online at www.biotimeinc.com and www.orthocyte.com.