After a month, however, the cells looked like adult heart muscle cells — elongated with striped patterns.
They next tagged these cells with a fluorescent protein and injected about 200,000 of the cells into the ventricle or lower heart chamber of newborn nude rats — rats with deficient immune systems that wouldn’t attack and reject the newly introduced cells.
After about a week, Kwon reports, the fluorescent cells were still rounded and immature-looking.
But they also found that those genes were similar to those activated, or turned on, in the hearts of newborn rats.
In their initial experiments designed to overcome the developmental roadblock, the researchers first created a cell line of immature heart cells taken from mouse embryonic stem cells.
Generating mature and viable heart muscle cells from human or other animal stem cells has proven difficult for biologists.
Now, Johns Hopkins researchers report success in creating them in the laboratory by implanting stem cells taken from a healthy adult or one with a type of heart disease into newborn rat hearts.After a month growing the human ARVC immature heart cells in the rat heart ventricles, the cells began to demonstrate properties of heart tissue from patients with the disease, Kwon says.Specifically, they accumulated lots of fat and had more cells dying than healthy cells appearing.This requires the completion of 30 credits in addition to the regular (90 or 120 credit) degree program. Canadians and Permanent Residents who are 21 years of age or older and who lack the normal pre-university schooling may be considered for admission to the MEP, which requires successful completion of a minimum of 18 additional credits.Please see Mature Entry for admissions requirements.The information provided is for reference purposes.