Microbiome critical for bone hormone action

PTH (parathyroid hormone) increases calcium levels in the blood and can either drive bone loss or bone formation, depending on how it is produced or Read more

More NMDA but less excitotoxicity? Now possible

Many researchers have wanted to enhance NMDA receptor signals to treat disorders such as schizophrenia. But at the same time, they need to avoid killing neurons with “excitotoxicity”, which comes from excess calcium entering the Read more

Update on pancreatic cancer: images and clinical trial

In 2018, Winship magazine had a feature story on pancreatic cancer. Our team developed an illustration that we hoped could convey the tumors’ complex structure, which contributes to making them difficult to treat. Oncologist Bassel El-Rayes described how the tumors recruit other cells to form a protective shell. "If you look at a tumor from the pancreas, you will see small nests of cells embedded in scar tissue," he says. "The cancer uses this scar Read more

Type 1 diabetes

Islet transplants from fish?

The shortage of human organ donors has led scientists to investigate animals as a potential source for transplantable organs or tissues. Pigs are often mentioned because of their size: similar to ours.

Recently, prospects for xenotransplantation brightened when Harvard geneticist George Church demonstrated the removal of dozens of endogenous retroviruses from the pig genome, in a tour de force of the CRISPR/Cas9 gene editing technique.

Emory researchers Susan Safley and Collin Weber have been exploring the possibility of using different animals for xenotransplantation: fish, specifically tilapia.

Why fish? This review details several advantages tilapia may offer in the field of islet transplant, but first – a reminder about islets.

Islets are the clusters of cells in the pancreas that produce insulin. Several clinical trials, including this one led by Emory’s Nicole Turgeon, have shown that islets isolated from deceased human donors can restore normal blood sugar regulation in patients with type 1 diabetes. Still, obstacles remain such as the shortage of human islets, and the loss of insulin independence over time, even with the use of drugs that hold off immune rejection.

For islet transplant, here are some of the proposed advantages presented by tilapia:

*tilapia have large, distinct islet organs called Brockmann bodies that are easy to isolate

*tilapia grow quickly and cost less to raise than pigs

*tilapia islets are resistant to hypoxia, thought to contribute to graft loss

*tilapia do not express alpha (1,3) gal, a carbohydrate structure present on mammalian cells that causes hyperacute rejection Read more

Posted on by Quinn Eastman in Immunology Leave a comment

Challenges in islet transplantation

Two recent research papers from the Emory Transplant Center describe research on pancreatic islet transplantation, an experimental procedure that could help people with type I diabetes live without daily insulin injections.

Islet transplantation may offer people with type I diabetes the ability to produce their own insulin again

As with other types of transplantation, the challenge with islet transplantation is to avoid rejection of the donated organ and to balance that goal against side effects from the drugs needed to control the immune system. These papers illustrate how that balancing act is especially complex.

In the last decade, transplant specialists developed a method for islet transplantation named the “Edmonton protocol” after pioneers at the University of Alberta. While the emergence of this method was a major step forward, there are limitations:

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Posted on by Quinn Eastman in Uncategorized 3 Comments

Pig stem cells: hope for Type 1 diabetes treatment

University of Georgia researchers recently reported on their work to create pigs with induced pluripotent stem cells. This type of cell, first developed about five years ago, has the ability to turn into any other kind of cell in the body.

An Emory transplant team, working with the UGA group, hopes to use this technology to develop pig islet cells as an alternative to human islets to treat patients with Type 1 diabetes. Type 1 diabetes usually occurs early in life and affects more than one million Americans who are unable to manufacture their own insulin because their pancreatic islets do not function.

Emory islet transplant team

The Emory Transplant Center has conducted clinical trials since 2003 transplanting human pancreatic islet cells into patients with Type I diabetes. Some of these patients have been able to give up insulin injections, either temporarily or permanently. Other sources of islets are needed for transplant though because of the large number of potential patients and because each transplant typically requires islets from several pancreases.

To create pigs using pluripotent stem cells, the UGA team injected new genes into pig bone marrow cells to reprogram the cells into functioning like embryonic stem cells. The resulting pluripotent cells were inserted into blastocysts (developing embryos), and the embryos were implanted into surrogate mothers. The resulting pigs had cells from the stem cell lines as well as the embryo donor in multiple tissue types.

The pluripotent stem cell process could allow researchers to make genetic changes to dampen or potentially eliminate the rejection of the pig islets by the human immune system.

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Posted on by Holly Korschun in Uncategorized Leave a comment