Bioengineered bone marrow cells let transplant recipients live drug-free

A mix of bioengineered cells can mean that transplant recipients no longer need to take a lifetime of anti-rejection drugs. This also makes transplants possible for patients without matched donors.
Written by Janet Fang, Contributor

Patients who receive kidney transplants usually end up taking drugs to help suppress their immune system from mounting an attack against the donated organ.

Up to 25 of these toxic immunosuppressant drugs need to be taken a day… for the rest of their lives. And these are known to cause side effects like high blood pressure, diabetes, and increased risk of infections.

Now, scientists have combined stem cells and other cells from bone marrow to promote a drug-free organ tolerance.

Not only does this free up transplant recipients from a lifetime of harmful drugs, this also makes transplants possible for patients who don’t have matched donors.

Previous research have found that mixing bone marrow stem cells from both the recipient and donor helps to promote organ tolerance – but this can also trigger graft-versus-host disease (GvHD), where donor immune cells attack the healthy tissues of the recipient.

So, to create an environment where two bone marrow systems exist and function in one person, a team led by Suzanne Ildstad the University of Louisville looked to bioengineered versions of cells from donor bone marrow.

In particular, they used donor stem cells that have been specially engineered to trick the recipients' immune system into thinking the donated organ is one of the patient’s own.

  1. Bone marrow stem cells were collected from donors.
  2. The team made those stem cells more ‘transplant-friendly’ by enriching them with graft-facilitating cells and removing GvHD-causing cells.
  3. Meanwhile, the recipients underwent a period of radiation and chemotherapy to suppress their immune systems.
  4. A couple weeks later, patients received their kidney transplants from their unrelated donors or a mismatched relatives, followed by the bone marrow mix.

The approach resulted in a nearly complete takeover of the recipient's immune system by the donor's immune cells, ScienceNOW explains.

And it seemed to work: 5 of the 8 patients maintained long-term normal kidney function and stopped taking immunosuppressants within a year. No sign of GvHD.

Ildstad is seeking to commercialize the approach through a company she founded called Regenerex, based in Louisville.

The work was published in Science Translational Medicine yesterday.

Image from Gray’s Anatomy via Wikimedia

This post was originally published on Smartplanet.com

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