Five patients in the United Kingdom have developed Alzheimer’s disease, which appears to be the result of contaminated injections they received as children decades ago, according to a new study that may change how scientists think about the causes of dementia and cause concern in patients. received the same treatment.
All five patients received human growth hormone injections from cadavers over several years to treat very short stature, according to the study published Monday in the journal Nature Medicine. Scientists obtained this hormone from the pituitary glands located at the base of the brain of cadavers.
But what scientists didn’t realize at the time was that in some cases another substance was also extracted from contaminating the batches: amyloid-beta protein. This protein plays a role in the formation of brain plaques seen in Alzheimer’s disease. The researchers said they cannot fully explain how exposure to these proteins might trigger the formation of plaques and tangles in the brain that cause Alzheimer’s disease.
Alzheimer’s cases generally fall into two main groups: cases caused by genetic mutations and cases that develop occasionally in the over-65 population due to a number of risk factors such as smoking, obesity and high blood pressure.
The patients in the new study did not fit into these two groups. They developed symptoms of dementia between the ages of 38 and 55. None of them had genetic mutations linked to early-onset dementia, according to the study.
The study’s authors said their findings suggest a possible third pathway for Alzheimer’s to develop: through contaminated medical products.
Some doctors who regularly treat children for hormone-related problems and who were not involved in the study said they were surprised by the findings.
Dr., who chairs the endocrinology section of the American Academy of Pediatrics. “This is new information that is unknown to the medical community,” said Kupper Wintergerst.
Other doctors said they were concerned that a treatment once considered safe was causing so much harm.
D., clinical professor of pediatric endocrinology at the UCLA David Geffen School of Medicine. “It’s disturbing to hear that Alzheimer’s is linked to a medical treatment,” said Dennis Chia.
Christopher Weber, director of global science initiatives for the Alzheimer’s Association, noted that the study was too small. The findings will be more reliable if other scientists obtain similar results in future studies.
Weber said there is no risk to the general public.
“Alzheimer’s disease is not contagious,” said Weber, who was not involved in the new study. “You cannot catch Alzheimer’s by caring for someone with Alzheimer’s. “Alzheimer’s disease is not transmitted through the air or by touching or being around someone with Alzheimer’s disease.”
Still, he said the study’s findings aren’t entirely new.
“We have long known that it is possible to create abnormal amyloid deposits, similar to what is seen in Alzheimer’s, by injecting amyloid-beta into the brain of an animal,” Weber said. “We are also transferring human Alzheimer’s genes into animals to initiate abnormal, Alzheimer’s-like processes in their brains.”
According to the new study, from 1959 to 1985, 27,000 children worldwide were given cadaver-derived growth hormone; these included approximately 7,700 patients in the United States. Doctors used hormones taken from cadavers before the synthetic version became available.
Other patients taking cadaver-derived hormones may have a higher risk of Alzheimer’s, the study authors said. But they added that they did not expect to see a large wave of cases.
Lead author of the study, Dr. “The actual risk of transmission of Alzheimer’s disease in this context is really very low, and these will probably be very rare cases,” said John Collinge. he said at a press conference on Thursday.
Collinge said patients should be aware of the potential risk for Alzheimer’s and seek testing and treatment if necessary.
“If we catch people at an early stage of Alzheimer’s, they may be able to adapt to existing treatments more easily,” he said.
Today, children treated for short stature are not at risk because doctors have been using synthetic growth hormone since 1985.
D., a professor emeritus at Children’s National Hospital who specializes in pediatric growth disorders. “I don’t think people should panic,” Paul Kaplowitz said.
Kaplowitz noted that U.S. manufacturers developed a safer way to purify cadaver-derived human growth hormone in 1977, significantly reducing the risk of contamination. Patients treated with cadaver-derived growth hormone in the United States after 1977 are probably at very low risk.
“You would think that if this were a big problem there would be a lot of cases by now,” said Kaplowitz, who was not involved in the new study.
Another dangerous protein
Although Collinge and his team’s previous research suggested that patients receiving cadaver-derived growth hormone might be at risk for Alzheimer’s, they began following the patients out of concerns about a different disease: Creutzfeldt-Jakob disease, or CJD, a rare and fatal condition. this was also caused by contaminated hormone samples.
CJD is a cousin of bovine spongiform encephalopathy, commonly called mad cow disease. More than 250 GH patients worldwide have been diagnosed with CJD.
Doctors believe patients developed CJD due to hormone samples contaminated with prions, little-understood proteins that can trigger normal brain proteins to fold into abnormal shapes. In the USA, 35 patients treated with cadaver-derived human growth hormone died due to CJD.
For decades, people living in or traveling to the United Kingdom or other places where mad cow disease has occurred have been banned from donating blood for fear of contracting the disease. The Food and Drug Administration lifted this ban in 2022.
Collinge said he doesn’t know whether the proteins thought to cause Alzheimer’s can be transmitted through blood transfusions or organ donations. A spokesman for the American Society for Transplantation said scientists know there is no link between organ transplants and an increased risk of Alzheimer’s.
“That’s an interesting question,” Collinge said at the news briefing. “This is not something we are looking into.”
Scientists have had evidence for some time that CJD can be transmitted through blood transfusions, and the American Red Cross has banned people receiving cadaver-derived growth hormone from donating blood.
However, a spokesperson for the American Red Cross said in a statement that there was “no scientific evidence” that donated blood could lead to the accumulation of amyloid protein in the body or increase the risk of Alzheimer’s. The Red Cross is in close contact with the FDA and other international health agencies that oversee blood safety to ensure its recommendations incorporate the latest science, spokesman Daniel Parra said.
New study raises questions about how Alzheimer’s begins. Alzheimer’s disease may have more in common with CJD than previously suspected, Collinge said.
“This may have important implications for the understanding and treatment of Alzheimer’s disease in the future,” he said in a statement. While there have been no other reported cases of people contracting Alzheimer’s through other medical care, this study “should lead us to consider measures to prevent accidental transmission through other medical or surgical procedures to prevent such cases from occurring in the future.”
For more information, patients treated with cadaver-derived human growth hormone in the United States can call the National Institute of Diabetes and Digestive and Kidney Diseases at 1-800-860-8747 or email healthinfo@niddk.nih.gov can send.
Patients receiving treatment in the UK can email the National Prion Clinic at uclh.prion.help@nhs.net.
This article first appeared on NBCNews.com.