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Protein Found on Stem Cells Protects Against Immune Attack

Mechanism Identified for Cross-Species Therapeutic Effects of Medistem's Universal Donor Stem Cell Product

Medistem Inc. (PINKSHEETS: MEDS) announced today publication of a peer reviewed paper identifying a molecule found on the company's lead product, the universal donor Endometrial Regenerative Cell (ERC), as a key component of cellular escape from immune attack. The study, titled "Resistance of neonatal porcine Sertoli cells to human xenoantibody and complement-mediated lysis is associated with low expression of alpha-Gal and high production of clusterin and CD59," was published in the journal Xenotransplantation as a collaboration between Medistem and the Institute of Organ Transplantation, Tongji Hospital, in Wuhan, China.

The study found that CD59, a molecule made by ERC, plays an important role in protecting cells from immune rejection when placed in contact with immune components from another species. The ERC is a mesenchymal-like stem cell that Medistem discovered in 2007 capable of generating heart, lung, brain, muscle, blood vessel, pancreas, liver, fat and bone tissue. The original description of this cell, which won the "Publication of the Year Award" may be found at http://www.translational-medicine.com/content/pdf/1479-5876-5-57.pdf.

"One of the fundamental aspects of Medistem's lead product, the Endometrial Regenerative Cell (ERC), is its ability to function without the need for tissue matching. In other words, the ERC stem cells act as universal donors. We have previously published that human ERC are effective in treating mice having a condition that resembles critical limb ischemia (see paper http://www.translational-medicine.com/content/pdf/1479-5876-6-45.pdf). We now believe that expression of the molecule CD59 on ERC may be one of the mechanisms by which these human cells can be used not only as a universal donor for humans, but also for the treatment of numerous diseases across a variety of animal species," said Thomas Ichim, CEO of Medistem.

Medistem has filed an IND with the FDA for treatment of critical limb ischemia (severe obstruction of the arteries that leads to decreased blood flow to the extremities) with ERC. Currently the company is in the process of completing additional experiments requested by the FDA before clinical trials can commence. Through physician-initiated compassionate use mechanisms Medistem has already published on human use of ERC in treatment of heart failure, Duchenne Muscular Dystrophy, and multiple sclerosis. A recent peer-reviewed paper describing ERC in treatment of heart failure may be found at http://www.intarchmed.com/content/pdf/1755-7682-3-5.pdf.

About Medistem Inc.

Medistem Inc. is a biotechnology company developing technologies related to adult stem cell extraction, manipulation, and use for treating inflammatory and degenerative diseases. The company's lead product, the endometrial regenerative cell (ERC), is a "universal donor" stem cell being developed for critical limb ischemia. A publication describing the support for use of ERC for this condition may be found at http://www.translational-medicine.com/content/pdf/1479-5876-6-45.pdf.

Cautionary Statement

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