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Published: 15 May 2024

Doctors Against Animal Experiments criticizes xenotransplantation research

On March 16, the 62-year-old Richard Slayman in Boston (USA) became the first living person worldwide to receive a pig kidney transplant. Nearly two months after the procedure, the patient has died. Nevertheless, the doctors involved from Massachusetts General Hospital (MGH) see Slayman as "a beacon of hope for countless transplant patients" (1). The German association Doctors Against Animal Experiments (DAAE) is appalled at how xenotransplantation research not only continues to sacrifice countless animals but also plays with the hopes of severely ill patients.

After Slayman, who developed kidney failure due to type 2 diabetes and hypertension, experienced the failure of a human kidney transplanted in 2018 and increasingly suffered from complications during dialysis, the doctors suggested the risky procedure to him. The kidney transplanted to him on March 16 came from a pig genetically modified to deactivate certain substances that could trigger the human immune system. Additionally, human genes were inserted, and porcine viruses were removed from the genome.

In 2022, two genetically modified pig hearts were transplanted, and the patients died 6 and 8 weeks after the transplantation (2). In Slayman's case, the doctors hoped for a longer survival since the pig kidney was better adapted to humans with a total of 69 genetic modifications compared to 10 modifications in the previously transplanted pig hearts. The transplantation of pig kidneys had previously been tested on baboons and brain-dead patients. Currently, nothing is known about the circumstances of Slayman's death. According to a press release from MGH, there are no indications so far that the patient's death is related to the xenotransplantation. In addition to Slayman, another patient, also suffering from diabetes, also received a pig kidney transplant, which, however, had to be removed in the meantime (3).

"It is disturbing how much medical research relies on increasingly complex technical procedures, degrading animals not only to test objects but also to arbitrarily genetically modifiable spare parts reservoirs," says Dr. Johanna Walter, scientific advisor at DAAE. In Germany, xenotransplantation research is being conducted at Ludwig Maximilian University (LMU) Munich. For at least three decades, pig hearts have been transplanted into baboons there. The monkeys often die in severe agony within a few hours or sometimes after a few weeks or months, which is publicly celebrated as a 'success.' However, the breakthrough that has been repeatedly announced as imminent for decades has yet to materialize (4).

The most common causes of kidney failure are diabetes and hypertension. Both conditions are largely attributable to poor diet, overweight, lack of exercise, and smoking. "The majority of people who will suffer from kidney failure in the future could avoid this organ damage today through simple lifestyle adjustments. This would be a risk-free and cost-effective measure that would also alleviate the shortage of donor organs, which serves as a justification for xenotransplantation research," says Walter.

Here, DAAD sees not only the healthcare system but also politics as having a duty to give greater emphasis to disease prevention, rather than waiting until patients are sick and desperate enough to consent to high-risk and ethically questionable experiments. Continuing to pour money into xenotransplantation research is deemed irresponsible by the association. Treatment options should be advanced through powerful and human-oriented research.