Catalan researchers discover that green tea improves intellectual ability in people with Down syndrome

Barcelona (CNA).- A compound present in green tea, epigallocatechin gallate, mixed with a protocol of cognitive stimulation, has been shown to improve intellectual ability of people with Down syndrome; it may additionally modify excitability, and functional connectivity of the brain. These are the results of a phase 2 clinical trial carried out by a team of scientists led by the Mar Institute of Medical Research (IMIM) and the Centre for Genomic Regulation (CRG) in Barcelona; also collaborating was a research group specialising in neuropharmacology, Clinical Pharmacology and Neuroscience Integrated Systems. A researcher from the aforementioned neuropharmacological group, Dr. Rafael de la Torre, stated that “it was a surprise to see that the changes are not just on a cognitive level, that is, reasoning ability, learning, memory and attention, but that they also suggest that the functional connectivity of neurons in the brain is modified”. The next step for De la Torre and for the head of the Cellular Neurobiology and Systems at the CRG and principal author of the study, Dr. Dierssen, is to move forward and conduct these studies on children, in which brain plasticity is not as limited.

 

The study was published in the journal ‘The Lancet Neurology’ on Monday. This is the first time a treatment proves effective in improving cognitive function in cases of Down syndrome, according to the head of Cellular Neurobiology and Systems at the CRG and principal author of the study, Dr. Dierssen. “However, we must make clear that our discovery is not a cure for Down syndrome, and one must try our results on larger population samples, but this can be a treatment to improve the quality of life of these people”, pointed out the doctor.

According to the World Health Organization, Down syndrome affects about one in 1,000 people worldwide, and is the most common cause of intellectual disability of genetic origin. It is caused by a trisomy in chromosome 21, that is, people with this syndrome have three copies, and not two, of chromosome 21. This means that the genes present in this chromosome are overexpressed.

The work of researchers from the IMIM and CRG focuses on the role of a compound called epigallocatechin gallate, which offsets this excess and inhibits one of the genes included in chromosome 21 (called DYRK1A) related to brain plasticity and some cognitive abilities. The results of the study suggest that people treated with epigallocatechin gallate and with a protocol of cognitive stimulation saw an improvement in their visual recognition memory, attention and self-control, and adaptive behaviour and autonomy, and that these changes can be correlated with biological changes in their brain connectivity.

The research focuses on molecular analysis and behavioural alterations in learning and memory in intellectual disability. In particular, the research has been centred around studying the gene DYRK in mice, which is responsible for many of the cognitive deficits and neuronal plasticity seen in Down syndrome. Once the effects of overexpressed DYRK1A were demonstrated in mice, the objective was to determine whether inhibiting it would obtain enhanced brain development. Together with another research group at the CRG, the teams successfully achieved this goal through gene therapy, but, unfortunately, it was in[JA1] applicable to humans. After epigallocatechin gallate was proposed as a possible inhibitor for the effects of DYRK1A, Dr. Dierssen started using this compound in the experiments, obtaining results which reaffirm its effectiveness in mice.

To make the leap from preclinical research to clinical trials, there needed to be a research group specialising in neuropharmacology present and collaborating. Indeed, the work contains the results of a clinical trial, led by the research group Clinical Pharmacology and Neuroscience Integrated Systems of Dr. Rafael de la Torre. The clinical trial worked with 84 persons with Down syndrome between 16 and 34 years old. “The results suggest that people who received treatment with the compound of green tea along with a cognitive stimulation protocol have achieved better scores in their cognitive abilities”, explains Dr. De la Torre. However, studies are still needed in larger population samples.

It was already known that epigallocatechin gallate inhibited the excess of the gene DYRK1A, and the success obtained in previous studies with mice suggested that the treatment could also work in humans. Scientists have not limited themselves to studying the effects on the participants in the study on only a cognitive level, the researchers have also carried out neuroimaging tests to assess whether this improvement corresponded to physical or neurophysiological changes in the brain. “It was a surprise to see that the changes are not just on a cognitive level, that is, reasoning ability, learning, memory and attention, but that they also suggest that the functional connectivity of neurons in the brain is modified”, explained Dr. De la Torre.

Dierssen and De la Torre plan to continue their research and to initiate a clinical trial with children with Down syndrome. “Our results have been positive in an adult population, in which brain plasticity is limited because the brain is already fully developed. We believe that if the treatment is applied to children, the results could be even better”, stated the pair of researchers. Thus, clinical trials with a larger sample population will be essential to ensure positive effects and the safety of possible future treatment, and to prescribe and recommend it to patients properly.