Mechanisms and secrets of Alzheimer's disease: exploring the brain

[Music] Alzheimer's disease was described for the first time in 1907 by the German psychiatrist alois alzheimer in performing a histopathologic study of the brain of his patient August II suffering from dementia he brought to light the presence of two types of lesions in the brain Sina plaques and neurofibrillary tangles he reached the conclusion of a distinct disease of the cerebral cortex a hundred years later thanks to current scientific techniques research has made a great leap in the understanding of the disease we know that the brain is made up of neurons and that these are interconnected to form a vast network these connections known as synapses enable the transmission of information from one neuron to another in Alzheimer's disease 10 to 15 years before the appearance of the symptoms two main lesions form in the brain senile plaques composed of amyloid beta protein and neurofibrillary tangles composed of tau protein how is the senile plaque formed on the surface of the neuron is a large protein called a PP normally a PP is sectioned by enzymes on the surface of the neuron and it fries a protein called amyloid beta the amyloid beta protein is then cleared in the body in the case of Alzheimer's disease there is an imbalance the amyloid beta protein is no longer regulated and is found in two greater quantity the proteins assembled to form into soluble fibrils and create senile plaques [Music] how are neural fibrillar eat angles formed when a neuron communicates with another a signal goes from the body known as soma to the synapse to transfer the information the signal passes through the skeleton of the neuron composed of microtubules these microtubules are stabilized by normal tau protein [Music] an Alzheimer's disease tau protein becomes defective and attaches from the microtubules thus the skeleton of the neuron dissociate as it is no longer maintained defective tau proteins then assemble to form filaments in the neuron [Music] without the skeleton the neurons degenerate and connections between the neurons are lost the abnormal accumulation of tau filaments in the neuron creates neurofibrillary tangles and eventually causes the death of the neuron how do the two lesions spread throughout the brain [Music] neurofibrillary tangles and senile plaques do not follow the same pathway in the brain overtime neurofibrillary tangles first developed in the region called the hippocampus which is essential to memory and learning they then reach the whole brain following a centrifugal movement the process causes a trophy which engenders global dysfunction the progression of the lesions corresponds with the symptoms of the disease which begin with memory problems followed by problems of language recognition and incapacity to perform gestures senile plaques developed differently they are initially observed in the cortex secondly in the hippocampus and then the senile plaques reach the whole brain following a sentry petal movement their progression does not correspond to the symptoms of the disease but numerous questions remain unanswered we know that the presence of the two cerebral lesions is necessary to develop Alzheimer's disease since one does not come without the other but which lesion comes first neurofibrillary tangles senile plaque the answer is still under debate many clinical trials destined to reduce senile plaques in the brain have failed in fact reducing them is not sufficient to eradicate the disease it has now been suggested that well before formation of senile plaques smaller forms of amyloid beta called oligomers appear to be toxic for neurons disturbing their communication when they fix on two synapses it would appear that the toxic oligomers and their accumulation Cina plaques are at the origin of neurofibrillary tangles which in their turn are responsible for symptoms the relationship between amyloid-beta protein and towel protein is still little understood what is the exact sequence of molecular mechanisms leading to the development of dementia what is the role of genetics and environmental risk factors in the appearance of the disease scientific research is essential in answering these questions thanks to researchers Alzheimer's disease is better and better known in its complexity and new avenues raise real hope for the eradication of this devastating disease you [Music]

Channel: Fondation Vaincre Alzheimer

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Id: dj3GGDuu15I

Length: 6min 27sec (387 seconds)

Published: Fri Oct 11 2013