SUNDAY, June 8 (HealthDay News) -- Adding a little shear stress along a vascular bypass graft during the procedure may help hold it together better in the long run, according to a new study.

Researchers report that gradually adding parallel pressure -- as opposed to normal perpendicular pressure -- to adult stem cells used in a graft helps then bind to the surfaces of the vessel.

The finding, expected to be presented during the annual meeting of the Society for Vascular Surgery being held in San Diego, could help development of a new tissue-engineered stem cell vascular bypass graft.

Integrins, molecules important for cell attachment on the surface of the stem cells, appear to be stimulated by shear force, according to the study. This helps these cells to remain attached to the inside of blood vessels.

"Firm attachment of the stem cells to the vascular graft would allow for the formation of a confluent monolayer of cells in the hopes of improving graft function," lead researcher Dr. Paul J. Dimuzio, a vascular surgeon at Thomas Jefferson University in Philadelphia, said in a prepared statement.

During the study, the researchers exposed human adipose-derived stem cells (ASC) differentiated toward endothelial-like cells to physiological levels of shear stress. Measurements of integrin activity and cell attachment were taken on sample culture plates precoated with collagen I, fibronectin or gelatin -- all vascular basement membrane components.

Future experiments will evaluate how well the stem cell grafts function as a bypass for occluded arteries, according to one researcher.

More information

The U.S. National Heart, Lung, and Blood Institute has more about coronary artery bypass grafting.