L’ Alzheimers it is among the most common forms of dementia and affects more than 55 million people worldwide, according to WHO data. A number unfortunately destined to increase: it is estimated that by 2050 they will be 139 million patients affected.
Despite the medical-scientific progress in the development of pharmacological therapies, there is still no effective cure.
Alzheimer’s is a chronic neurodegenerative disease characterized by the destruction of nerve cells. The disease involves an alteration of the cognitive functions of the individual in a consistent and irreversible way, inducing states of confusion, mood swings and disorientation. The illness Alzheimer’s disease is associated with the presence of plaques that interfere with the transmission of nerve impulses, leading to progressive atrophy of the brain.
According to a study published today in the scientific magazine Brain and led by a team ofUniversitè Laval and Rush University Medical Center in Chicago the Alzheimer’s disease would be associated with one reduction of insulin receptors in cerebral microvessels. This, in turn could contribute to brain insulin resistance and to formation of amyloid plaquesone of the hallmarks of Alzheimer’s disease.
The results support the idea that Alzheimer’s is a neurodegenerative disease with a strong metabolic component.
The work was led by Frederic Calon, professor at the Faculty of Pharmacy and researcher at the Institute of Nutrition and Functional Foods and the CHU de Que’bec-Universitè Laval Research Center. It is based on a longitudinal study begun in 1993 and involving about 1,100 members of about thirty religious congregations in the United States. The participants agreed to undergo yearly medical and psychological tests and to donate their brains after they die. The brain article is based on data from 60 deceased people who participated in this large study.
Examination of their brains revealed that insulin receptors are found primarily in microvessels, not neurons, as previously thought. It also reveals that insulin receptor alpha-B subunits were less prevalent in the microvessels of people diagnosed with Alzheimer’s. Another piece of information concerns cognitive test scores, which are lower in subjects with fewer alpha-B insulin receptors in their microvessels. Finally, subjects with fewer alpha-B insulin receptors in their microvessels had more beta-amyloid plaques in their brains.
Calon’s comment: “Our study shows that drugs do not need to cross the blood-brain barrier of microvessels to affect brain insulin resistance. Instead, they can target insulin receptors located in brain microvessels. This broadens the range of drugs that could be tested for Alzheimer’s”.