(ORDO NEWS) — Scientists have shown that regular injections of GnRH help improve cognitive performance in patients with Down syndrome.
This hormone is known for its role in the regulation of reproductive function, but also affects various parts of the brain, and its deficiency caused by genomic mutations leads to a deterioration in cognitive function.
Scientists from the University Hospital of Lille (France) and the University Hospital of Lausanne (Switzerland) have proposed a new method for improving cognitive functions in people with Down syndrome – injection of the hormone GnRH.
First, the researchers identified dysfunction of GnRH-releasing neurons in mice with a Down’s syndrome model and its detrimental effects on cognitive function. They then conducted a pilot study of injection therapy with GnRH in patients with Down syndrome.
Down syndrome is a trisomy of chromosome 21, occurs in about one in 800 newborns and leads to numerous disorders, including cognitive decline. As they age, 77% of people with this disease experience symptoms similar to those of Alzheimer’s disease.
In addition, they often experience the loss of smell that is typical of neurodegenerative diseases, and men may experience a lack of puberty.
Investigating the cognitive impairments that accompany Down’s syndrome, scientists drew attention to the neurons of the hypothalamus that secrete GnRH. This hormone stimulates the anterior pituitary gland to secrete gonadotropic hormones: luteinizing and follicle-stimulating.
They, in turn, regulate the functioning of the reproductive system. However, scientists have shown that GnRH can also affect other areas of the brain, including those involved in cognition and information processing.
Studying mice with a model of Down syndrome, the authors of the work found that five different microRNAs encoded on chromosome 21 and necessary for the secretion of GnRH do not function in them. This leads to abnormalities in the development of GnRH-secreting neurons.
The results were confirmed both at the genetic and cellular levels. The scientists demonstrated that the progressive cognitive and olfactory impairment observed in mice with trisomy was closely associated with impaired GnRH secretion.
At the same time, the restoration of its physiological function led to an improvement in cognitive and olfactory abilities.
Therefore, the next step was pilot clinical trials on patients, which involved seven men with Down syndrome aged 20 to 50 years. They received one dose of GnRH every two hours (this allowed the natural rhythm of hormone secretion in the body to be reproduced) for six months.
From a clinical point of view, cognitive abilities changed in six of the seven patients: they showed improvement in understanding of instructions, thinking, perception of three-dimensional space, attention and episodic memory.
Although the treatment did not affect the sense of smell. These results were confirmed by brain imaging of patients: it showed a significant increase in the connection between different areas of the cerebral cortex.
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