09.10.2023 Diabetes

Transplant problems

Study finds that organs for pancreatic islet donation are rejected due to factors ranging from donors’ health problems to a lack of trained personnel

One promising alternative therapy for diabetes is the transplantation of isolated pancreatic cell islets from the pancreases of living but brain-dead donors | Image: Shutterstock

Type 1 diabetes (mellitus) is a result of a person’s own immune system destroying beta cells in the pancreas, causing the organ to produce little or no insulin—the hormone responsible for transporting glucose, the body’s main source of cellular energy, to muscle cells. People with the condition therefore require insulin injections for the rest of their lives. The treatment, however, often failes to prevent the most common complications of the disease.

One promising alternative therapy is the transplantation of isolated pancreatic cell islets from the pancreases of living but brain-dead donors. However, the health conditions of the donors, as well as technical issues involved in the conservation, transportation, and isolation of these cells, prevent the procedure from being carried out more often in Brazil, according to a study published in the journal Diabetology & Metabolic Syndrome by researchers from the School of Medicine at the University of São Paulo (FM-USP).

The authors, members of FM-USP’s Cellular and Molecular Therapy Research Center (NUCEL), carried out a retrospective analysis of pancreases received between January 2007 and January 2010 and the reasons why most of the organs were refused.

A total of 558 pancreases were offered by the São Paulo State Transplant Center in the period, 512 of which were rejected, with 46 accepted for islet isolation and transplantation.

The data suggest that hyperglycemia, technical issues, age, positive serology results, and hyperamylasemia are the leading reasons for organ refusal. Hyperamylasemia—an excess of the digestive enzyme amylase—may be associated with head trauma, one of the biggest causes of brain death in Brazil. It was the fifth most common reason for pancreas refusal in the study (8.2%).

The most common reason for pancreases being rejected, however, was hyperglycemia (14.8%), which can be harmful to pancreatic islets, since it is associated with an increased death rate of beta cells—the very cells that synthesize and secrete insulin.

Elevated glucose may be a consequence of the donor being admitted to an intensive care unit (ICU), where medication and parenteral nutrition can contribute to glucose instability.

Technical issues accounted for 8.7% of rejections, the second most common reason. The difficulties include insufficient numbers of personnel qualified to isolate islets, problems related to the availability of specific reagents and supplies, and organ transportation issues related to the long distances between the hospitals where donors are located and the transplant centers.

Finally, the advanced age of donors (8.5% of rejections) and positive serology results for a series of infections (8.4% of rejections) complete the list of obstacles to obtaining pancreatic islets.

“With respect to the supply of pancreases for islet transplantation in Brazil, our study highlights the need to concentrate efforts on improving the quality of donor organs in the ICU and minimizing technical problems,” wrote the study authors.

“We believe that the conclusions shown in this work could help to increase the availability of better-quality pancreases, leading to improved islet isolation and transplant outcomes,” they concluded.

In 2002, NUCEL became the first center in Brazil to perform a pancreatic islet transplant. Five patients underwent the procedure, which consists of one or more infusions of isolated cells into the bloodstream.

Only two other centers in the country perform islet isolation and transplantation: a laboratory at the Pontifical Catholic University (PUC) of Paraná, in Curitiba, and another at Hospital de Clínicas in Porto Alegre, Rio Grande do Sul.

In most cases, people with diabetes mellitus who undergo the treatment begin to produce their own insulin and rely less on hormone injections, in addition to reducing or eliminating episodes of hyperglycemia.


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