Posted by: Dan | November 16, 2006

Cytograft: Growing Replacement Parts

Scientific American has their yearly Top 50 leaders in science, technology and society out in their latest issue, and I thought one was worth advertising here on my blog… in the category “Trends in Research, Business and Policy”: Growing Replacement Parts.

With the goal of reproducing the mechanical properties of soft tissue, bioengineers William R. Wagner and Michael S. Sacks of University of Pittsburgh have fashioned an inexpensive polymer, polyester urethane urea, into a scaffold. This cylindrical scaffold’s strength resembles that of a pulmonary valve because it responds to stress differently depending on the direction in which the stress is applied. During fabrication, living cells can be integrated into the scaffold, and its mechanical properties can be controlled to create a made-to-order patch of tissue.

At an April conference, Wagner claimed that a patch of this biomaterial infused with smooth muscle cells promotes healing and reduced formation of scar tissue in the hearts of rats recovering from cardiac arrest. Vascular tissue (tissue rich with blood vessels) is the hardest tissue to engineer. The researchers hope to repeat the experiment using a patch infused with muscle-derived stem cells in the hopes of even better results.

Already having reached the phase of clinical trials, the California bioengineering company, Cytograft, has patented a method for growing blood vessels from a human patient’s own cells. The mechanical strength of the vessel comes from fibroblasts (connective tissue cells) arranged in sheets.

Tissue engineering holds a great deal of promise for progress in all areas of medicine, and I know of at least one lab here at Cornell that is working on alternative approaches to growing vascular tissues in vitro. Exciting stuff.



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