ALZHEIMER’S - TYPE III DIABETES
Alzheimer’s disease is characterized by dementia. It
is a disease of the brain which progressively affects thought process, abstract
reasoning, memory, speech, ability to perform simple tasks, etc. A validation of this neurodegenerative
disorder can only be made by autopsy
of the patient’s brain, which can reveal
the associated neuronal loss or cell death. The causative agents are
extracellular neuritic plaques and intracellular neurofibrillary tangles with
abundance of amyloid precursor protein, viz, Beta-amyloid, primarily in the
frontal and temporal lobes including hippocampus. These are insoluble deposits
which result in disruption in synaptic circuitry, cerebral atrophy, ventricular
enlargement and the consequential dementia. It is said that major loss of
volume is observed in the temporal lobe. In more advanced stages, it can spread
to other regions of the brain.
Research by neuropathologists at Rhode Island Hospital and Brown Medical
School, has revealed that development of plaques and the resultant loss of
neurons in Alzheimer’s Disease is because of abnormalities in insulin
signalling. Acetylcholine deficiency is
said to cause dementia. Insulin and Insulin like growth factor (IGF-I) stimulate
the production of an enzyme responsible for synthesising acetylcholine in the
brain. Because of the direct link
between the two, Alzheimer’s is being recognised as Type-III diabetes.
Type-I diabetes results when the Pancreas cannot make insulin as the
body’s own immune system destroys the insulin producing cells. On the other hand, when the Pancreas produce extremely small
quantities of insulin or when the body
is unable to respond to insulin, it is termed Type-II diabetes. Why is insulin so important can be understood
from how it works in the human body. All the cells in the body require energy
for functioning. In order to obtain energy
a large part of the food eaten is broken down to sugar called glucose.
Blood stream does the job of transporting glucose to the cells for further
usage as energy. Insulin mediates the transmission of glucose into cells for
further use. Pancreas keep releasing insulin in little amounts into the blood.
In case the blood glucose level rises, Pancreas increase the quantity of
insulin in blood for its ultimate transport to the cells. In the opposite case,
when blood sugar levels are low, the body signals us to eat and simultaneously
the Liver releases glucose for compensating the requirement.
Insulin expressed in the brain is a key factor for survival of the brain
cells and formation of memories. It is
said that the insulin receptors in the brain cells are damaged because of
the senile plaques, etc rendering the brain insulin resistant. In other words this could be a neuroendocrine
disorder and is being termed as Type-III diabetes. Diabetics, particularly
those with Type-II, are more at risk, it is being postulated. Researchers are working on this hypotheses
and growing evidence implicates
unhealthy diet and lifestyle for the increasing number of patients. Low glycemic diet, control over intake of
nitrates and a healthy life style including exercise, are being suggested to
counteract the disease.
PS:
Times of India has reported on 18.1.2013 that a London based Indian researcher Dr. Mahaveer Golechha (who obtained his doctorate from All India Institute of
Medical Sciences) has been selected by US based Alzheimer’s Drug Discovery
Foundation for receiving the ‘Young Investigator Scholarship Award’ award for
his work on ‘naringin’ which is a bioflavonoid found in grapes and other citrus
fruits and has significant anti Alzheimer’s activity. The award will be presented to him at the 7th
Annual Drug Discovery for Neurodegeneration Conference to be held in San
Francisco next month.
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