Following up on previous studies, Hopkins cardiologists used a thin tube to extract samples of heart tissue no bigger than a grain of rice within hours of the animals' heart attacks, then grew large numbers of cardiac stem cells in the lab from tissue obtained through biopsy, and within a month implanted the cells into the pigs' hearts. With help from a blue-dye tracking system, the scientists have shown that within two months the cells had developed into mature heart cells and vessel-forming endothelial cells.
"This is a relatively simple method of stem cell extraction that can be used in any community-based clinic, and if further studies show the same kind of organ repair that we see in pigs, it could be performed on an outpatient basis," says Eduardo Marbán, M.D., Ph.D., senior study author and professor and chief of cardiology at The Johns Hopkins University School of Medicine and its Heart Institute. "Starting with just a small amount of tissue, we demonstrated that it was possible, very soon after a heart attack, to use the healthy parts of the heart to regenerate some of the damaged parts."
Marbán cautions that no overall improvements in heart function have yet been shown in these studies, which were not designed to establish such changes and used relatively low numbers of infused cells (10 million or less). "But we have proof of principle, and we are planning to use larger numbers of cells implanted in different sites of the heart to test whether we can restore function as well," he says. "If the answer is yes, we could see the first phase of studies in people in late 2007."
The latest Hopkins findings are scheduled to be presented Nov. 13 at the American Heart Association's annual Scientific Sessions in Chicago. They are believed to be the first results in animal studies to show that so-called cardiac stem cell therapy can be successfully applied with minimally invasive methods to circumstances closely resembling those in humans. Scientists say the results build on earlier studies with cardiac stem cells in mice and humans that demonstrated success in regenerating infarcted heart muscle and restoring heart cell function post-infarct.
For the study, cardiac stem cells were extracted by tissue biopsy from eight pigs whose main arterial blood supply was tightened for more than two hours, duplicating the effects and damage caused by heart attack.
Using techniques developed in Marbán's lab, researchers extracted about a million cardiac stem cells from undamaged heart tissue, growing them without the use of potentially dangerous chemical stimulators.
After three weeks, the stem cells turned into spherical balls of cells that mimicked the electrical properties of heart muscle cells. The so-called cardiospheres yielded on average more than 14 million cells.
Within a month after the initial heart attack, a catheter tube was inserted into an artery in the pig leg for infusing the cardiospheres. Previous research had shown that they would on their own migrate to the damaged zones of the heart. Marbán's team was able to confirm this because they had labeled the stem cells with a gene that codes for an enzyme producing a blue dye, which could be seen under a microscope.
Months later, when researchers examined the hearts to see if any damaged tissue had been repaired, they found blue spots indicating where the stem cells had taken root. Closer examination of results revealed that stem cells had matured and grown in the border zones of the damaged area, where researchers suspect both dead and living tissue mingle and some blood supply remains.
"The goal is to repair heart muscle weakened not only by heart attack but by heart failure, perhaps averting the need for heart transplants," says Peter Johnston, M.D., study author and a Reynolds Foundation postdoctoral cardiology research fellow at Hopkins' Heart Institute. "By using a patient's own adult stem cells rather than a donor's, there would be no risk of triggering an immune response that could cause rejection."
David March | EurekAlert!
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy