Friday, September 20, 2013

Stem cell stories that caught our eye: speedier creation of iPS cells, heart rhythms and arthritis

Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun.

Speedy route to reprogrammed stem cells. Many outlets carried news this week of a paper in Nature by a team in Israel that dramatically boosted the efficiency of reprogramming adult cells such as skin into embryonic-like stem cells called iPS cells. The efficiency jumped from at best a few percent to nearly 100 percent of cells treated converting to the iPS state. Our friend Paul Knoepfler blogged about how that efficiency generally will not matter much for patients when the goal is to use a patient’s own cells to create repair tissue that immunologically matches their own.

Nearly every writer glossed over a more important milestone in the paper. The team got the adult cells to convert to stem cells in just seven days instead of the usual four to six weeks. If you have had an acute injury such as a heart attack or stroke that time savings could be a lifesaver. Ed Yong did one of the better pieces on the research in The Scientist.

Making it easier to create the right neighborhood. Stem cell scientists are increasingly realizing that if you want to grow a stem cell in the lab and have it mature into an adult cell that functions appropriately you need to try to recreate the environment, or neighborhood, if would grow up in naturally. This was a theme of this year’s meeting of the International Society for Stem Cell Research, which we wrote about here.

The web publication RedOrbit wrote about work at Case Western in Cleveland that maps one neighborhood in detail. The work published in Advanced Materials focuses on turning mesenchymal stem cells into bone or cartilage. With my creaky knees I’m always on the lookout for articles on research trying to get this cell conversion right.

They found that the cells respond to a three-dimensional gradient of signals; that is they react to chemical factors and physical triggers depending on their location. They found one chemical factor that can promote bone and another that can promote cartilage, which is key to eventual repair of arthritic knees.

A light switch for the heart. In a few years, well most likely quite a few years, if you have an abnormal heart rhythm you might choose to have a few opsins instead of an electronic jolt from a mechanical device. So what’s an opsin. They are proteins that are sensitive to light. When they are on the surface of a cell and are struck by light they can open or close hatches that allow passage of signals like those that tell a heart muscle cell to beat. A team at Stanford has already placed the genes for opsins into heart muscle cells in the lab dish and shown those cells do change the way they beat based on light. The researcher’s goal is to do this same thing with stem cells from a patient and convert them into light-sensing heart muscle that can be grafted onto the patient’s heart.

Given the enormous complexity of the heart’s normal electrical signaling system, getting new cells to replicate a normal beat will take a long time to perfect. This piece in HealthCanal does a nice job of explaining the intricacies of this new science and its long-term potential.

We have a short video of heart cells created from stem cells beating in a lab dish on our web site.

iPS cells reveal drug for heart rhythm. In this blog we frequently write about disease-in-a-dish models for understanding disease. This is when researchers take skin or other adult cells from a patient and reprogram them into iPS type stem cells. They then mature those into the type of cells that malfunction in a disease, such as heart muscle, and look to see how the cells with the genetic predisposition to disease are different from normal cells. A team from Singapore did this with cells from a child with a type of heart rhythm error knows as Long QT syndrome. Once they had beating heart muscle from the patient in a dish they tested various drugs on the cells and found one—a drug that is not normally used for the disease—corrected the rhythm. The team won the best poster prize at the European Society of Cardiology earlier this month and was written up by ScienceDaily.

Don Gibbons

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