By Janis Siegel, Jewish Sound Correspondent
Each year, many heart disease patients in the U.S. and around the world die waiting for a heart transplant because there are just not enough organ donors to serve all of the patients on waiting lists.
Tissue engineering is now becoming a real option for patients and ongoing research is demonstrating that it can restore the heart’s function after a heart attack.
To date, treatment with a manufactured tissue grid that replaces damaged heart tissue has been done mainly by replacing the damaged heart tissue with a collagen grid harvested from pig hearts.
But many patients’ own immune cells often attack the foreign animal cells, which causes the fix to fail.
However, Dr. Tal Dvir is hoping that heart attack patients in the near future may actually have hearts of gold now that the Tel Aviv University researcher found that a mesh-like patch of heart tissue infused with gold nanoparticles, microscopic particles of common materials that take on different properties when formed at this size, can only eliminate the risk of the patient’s immune cell rejection. At the same time, the patch also appears capable of generating its own electrical impulses that regulate the rhythm and beating function of a normal heart.
“Gold nanoparticles are promising candidates for tissue engineering, since they can be designed to minimize toxicity and have been used in drug delivery, imaging and cancer therapy,” Dvir told TAU staff.
“Our goal was twofold,” Dvir said. “To engineer tissue that would not trigger an immune response in the patient, and to fabricate a functional patch not beset by signaling or conductivity problems.”
In his team’s latest study, published in the journal Nano Letters in September 2014, Dvir, a member of the George S. Wise Faculty of Life Science in TAU’s Department of Molecular Microbiology and Biotechnology and the Center for Nanoscience and Nanotechnology, also collaborated with TAU’s Department of Materials Science and Engineering for the research.
Researchers found that this gold-laden collagen heart tissue grid can then be surgically implanted as a patch to replace damaged tissue and improve heart function in patients.
“We now have proof that these…cardiac patches improve heart function after heart attacks with minimal immune response,” Dvir said. “We plan to move it to large animals and, after that, to clinical trials.”
Dvir has been awarded fellowships from the American Heart Association, the Alon Fellowship for Young Investigators, the Israeli Ministry of Education, the Slezak Super Center Award for Cardiac Research, and the Marie Curie Award for Young Investigators.
In previous research with gold nanoparticles, they have been used in cancer therapies to promote drug delivery and to improve imaging tests.
In tissue engineering, gold nanoparticles can be designed to reduce toxicity, either from drugs that are used or a patient’s reaction to the tissue grid.
After the gold nanoparticle mesh grid is placed into the damaged heart, its function could be restored to that of a healthy heart. However, Dvir wrote, the tissue will eventually break down and need to be repaired.
In Feb. 2014, Dvir also experimented with the omentum, a sheet of fat attached to the bottom edge of the stomach, as an underlying collagen grid for cardiac patches in heart patients.
“We envision that this approach…may open up new opportunities in the broader field of tissue engineering and personalized regenerative medicine,” wrote Dvir and the TAU team in the journal IOP Science.
Also in Feb. 2014, the group at TAU experimented with albumin, a simple protein found in egg whites, milk, and blood serum, by manipulating and fabricating electrically woven albumin fibers.
“For the first time, a three-dimensional cardiac patch was fabricated from albumin fibers,” wrote Dvir’s group. “We hypothesized that since albumin fibers’ mechanical properties resemble those of cardiac tissue… they can support the assembly of cardiac tissues capable of generating strong contraction forces.”
Simply put, simulated heart tissue from an albumin-based source conducted and improved electrical impulses in the heart and functioned well.
“Our measurements showed that the scaffolds have improved elasticity…and that they are capable of adsorbing serum proteins,” he wrote, “leading to strong cell-matrix interactions.”
Longtime Jewish Sound correspondent and freelance journalist Janis Siegel has covered international health research for SELF magazine and campaigns for Fred Hutchinson Cancer Research Center.