Stem cell technology company Aldagen, which last year withdrew initial public stock offering plans that could have raised up to $80 million to finance research and development and clinical trials, is now raising money in much smaller increments.

The Durham-based company is trying to raise $645,004, according to an amended securities filing — $120,000 more than the $525,004 mixed offering of debt, options and warrants that launched last September. A total of 13 investors have participated so far raising $585,004, the filing shows.

Aldagen is developing regenerative cell therapies for cardiovascular conditions. The company’s technology isolates specific adult stem cells that express high levels of the ALDH enzyme, which plays an important role in the development of stem cells and progenitor cells.

Aldagen believes that these cells have the potential to promote regeneration of cells and tissue, including blood vessels. Aldagen’s targets include critical limb ischemia, a severe artery obstruction that decreases blood flow to the body’s extremities. The company is also researching a regenerative cell therapy for stroke.

Venture capital-backed Aldagen has raised more than $60 million from investors including the Aurora Funds, Intersouth Partners, Harbert Venture Partners, CNF Investments and Tullis-Dickerson.

The company in 2009 filed plans to go public. Last April, the company withdrew those plans citing market conditions. But Aldagen is still pushing forward on clinical studies. Last June, Aldagen enrolled its first patient in a phase 2 clinical trial studying candidate ALD-401 as a possible treatment for stroke.

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