Cardiomyocyte regeneration research a focus at Penn Medicine

One of the most significant recent developments in cardiac research at Penn Medicine was achieved by mimicking the regeneration mechanisms of fish and frogs.

“A question that we have been asking for some time is how we can get the mammalian heart — the human heart in particular — to repair itself, since it doesn’t do it that well,” Ed Morrisey, PhD, professor of medicine, professor of cell and developmental biology, and scientific director of the Institute for Regenerative Medicine in the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, told Cardiology Today. “We started out with the idea that lower animals — for example, zebrafish — can do this quite readily.”

Cardiology Today about the heart muscle repair mechanisms of lower species, and how University of Pennsylvania researchers are incorporating these adaptations into human myocardial muscle regeneration.

Read the full spotlight on Healio here.

Penn-led Study Resolves Long-disputed Theory About Stem Cell Populations

Adult stem cells represent a sort of blank clay from which a myriad of different cell and tissue types are molded and as such are of critical importance to health, ageing and disease.  In tissues that turn over rapidly, such as the intestines, the self-renewing nature of stem cells and their susceptibility to cancer-causing mutations has led researchers to postulate that these cells also act as the cell of origin in cancers. The rarity of adult stem cells relative to their differentiated daughter cells has, however, made them historically difficult to study.

Over the years, researchers have hypothesized that the body maintains a population of mutation- and injury-resistant “reserve” stems cells that serve as a kind of dormant reservoir from which all other cells in a given tissue can be derived. Yet researchers have been conflicted about the precise identity of this population of cells.

Now, a team from the University of Pennsylvania has helped identify key characteristics that distinguish reserve stem cells from other stem cell populations that had been purported to have similar properties. The work, which employed single-cell gene expression analyses as well as other cutting-edge techniques, demonstrated that, in the intestines, reserve stem cells are a distinct population from so-called “label-retaining cells.” The two populations were long believed to be one and the same.

“The devil is in the details,” said senior author Christopher J. Lengner, an assistant professor in the Department of Biomedical Sciences in Penn’sSchool of Veterinary Medicine and member of the Penn Institute for Regenerative Medicine. “You need an assay with single-cell sensitivity to address the potential heterogeneity in the cell population being study and thus to truly understand what these cells are. Now that we have that level of resolution, we can begin to ask questions that are relevant to questions such as how cancer is initiated, a process that starts in a single cell.”

Read the full article here.

The paper appears in the journal Gastroenterology.

Making new cells by direct cell conversion rather than from stem cells

The regenerative medicine field has been fueled for years on the idea that we can generate new types of cells, as needed for biomedical purposes, from stem cells. Yet recent advances in being able to convert one adult type of cell into another are leading to new ideas about regeneration in the future. The review below describes the latest in the emerging field of “direct cell conversion.”

A Simpler Twist of Fate, Michael Eisenstein. Nature, June 2016.

View article here.