The first suspected cases of transmission of Alzheimer’s disease are described | The science

It was an unintentional experiment with tragic results. Thousands of short people around the world were given growth hormones extracted from the pituitary glands of cadavers. Treatment was stopped around 1985 when it was discovered that these intramuscular injections could transmit prions that cause fatal Creutzfeldt-Jakob disease, similar to mad cow disease. A new study has revealed another undesirable effect of these treatments. A team from University College London believes that hormone treatment of the pituitary gland (a pea-sized gland at the base of the brain) transmitted Alzheimer’s disease to five people in the United Kingdom. These will be the first known cases of random transmission of the disease.

About 55 million people worldwide suffer from dementia, most cases associated with Alzheimer’s disease. A catastrophic, unintended experiment could shed light on the mysterious mechanisms of a disease for which there is still no effective treatment. Abnormal accumulations of two proteins are often found in the brains of deceased patients: beta-amyloid and tau. The same researchers, led by neurologist John Collinge, warned in 2015 that they had found suspicious beta-amyloid plaques in the brains of six people who died of Creutzfeldt-Jakob disease after taking growth hormones. In 2018, they discovered beta-amyloid in decades-old batches of the hormone and found that these proteins caused dementia in laboratory mice.

Collinge’s team is confident that they have discovered the first five known cases of accidental transmission of Alzheimer’s disease. All victims received growth hormones from cadavers, often for years, and began to show symptoms of dementia between the ages of 38 and 55, despite lacking the genetic variants present in other early cases. The opening will be announced this Monday in a specialist magazine. Natural medicine.

The early signs of 2015 caused global alarm due to some erroneous headlines, especially in the tabloid press. British tabloid Daily Mirror the cover said, “Alzheimer’s can give you the disease.” Collinge’s team now emphasizes that cadaveric hormone treatments were discontinued decades ago and that “there is no evidence that beta-amyloid can be transmitted in other contexts, such as during activities of daily living or in the provision of routine care.”

However, the authors suggest that we reconsider current measures to prevent accidental transmission of Alzheimer’s disease during invasive surgical procedures. “The main problem is with the instruments used in neurosurgery, we must ensure that they are decontaminated,” Collinge explains to EL PAÍS.

An international study conducted just over a decade ago identified 226 cases of Creutzfeldt-Jakob disease caused by growth hormone treatment in cadavers. Epidemiologist Fernando García López explains that not a single case of the disease has been registered in Spain, despite the fact that more than a hundred cases have already been identified in neighboring France. García López of the National Center of Epidemiology detailed that eight cases of Creutzfeldt-Jakob disease, caused by implants of the dura mater (one of the membranes that protect the brain) after brain tumor surgery, have been reported in Spain. Since 1987, the epidemiologist explains, the dura mater obtained from corpses began to be treated with caustic soda, and the problem disappeared.

Alzheimer’s disease is not contagious

Pascual Sanchez Juan, neurologist

Between 1959 and 1985, almost 2,000 people in the United Kingdom were given growth hormones obtained from cadavers. To date, approximately 80 cases of Creutzfeldt-Jakob disease caused by this treatment have been reported. The researchers say one would expect more cases of Alzheimer’s disease in this group of patients. Epidemiologist Fernando García López recalls that Spain has had a surveillance system in place since 1995 that analyzes whether patients with Creutzfeldt-Jakob disease received growth hormones decades ago. “We had to find them. Why did France have 119 cases and we have none? “It’s a mystery,” he says.

John Collinge’s laboratory had already demonstrated in 1996 that the new variant of Creutzfeldt-Jakob disease was caused by the same strain of prions—abnormal transmissible proteins—that caused mad cow disease. A British neurologist believes that the lessons learned from this prion disease can be applied to Alzheimer’s disease. Collinge and colleagues suggest that beta-amyloids do not respond to a single profile, but rather form a “cloud of diverse species,” as occurs with prions. Ignoring this heterogeneity could contribute to the emergence of resistance to early Alzheimer’s drugs.

Neurologist Pascual Sanchez Juan It’s stupid. “Alzheimer’s disease is not contagious. There is no risk associated with communicating with patients at home or in nursing homes,” he reassures. Sánchez Juan is the scientific director of the Foundation Research Center for Neurological Diseases in Madrid. “If we can know the specific strain, we can better target treatment for each patient, but we have not yet been able to correlate this diversity of beta-amyloid plaques with the different clinical subtypes of Alzheimer’s disease,” he complains. An expert from the Spanish Society of Neurology is optimistic: “Alzheimer’s disease probably occurs for many reasons, but there are many mechanisms that we do not know about. The new study represents a unique scientific experiment. They unintentionally introduced pathology to patients. Now they will be able to clarify things that would not otherwise be possible.”

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