Did you know that Parkinson’s disease and Alzheimer’s disease share the same causal cellular pathway? This pathway is the MAPK pathway which is involved in cell proliferation, differentiation, survival, death, and transformation. The pathway is believed to be started when the cell is under oxidative stress. Oxidative stress is caused by imbalance between the production of reactive oxygen, which are toxic to the body, and the natural ability of the body to react with or bind to them and detoxify the free oxygen radicals. These free oxygen molecules can bind to other molecules in the cells and cause damage. Once the damage was done in one cell, the free oxygen can spread to neighboring cells and cause damage to them as well.
Here is a brief explanation of how these two diseases share a common activation pathway. When a cell is under stressful condition due to, for example, genetic mutations or aging, the free radical formation is increased and this activates the MAPK pathway, specifically those activate p38 and JNK, which facilitates the mechanisms of cell inflammation and eventual cell death. In the Alzheimer’s disease and Parkinson’s disease, the MAPK activation leads to the death of the neurons which release dopamine, an essential neurotransmitter to mediate cellular activities in the regions of the brain important for memory, movement, and several other physiological and psychological functions.
As we talked about Alzheimer’s disease in my blog from last week, let’s take a brief look at Parkinson’s disease and MAPK pathway this week. Parkinson’s disease is mostly characterized by the formation of Lewy bodies in Substantia nigra of the brain. Substantia nigra is the region in the brain that is rich in dopamine releasing neurons called ‘dopaminergic’ neurons. These dopaminergic neurons project to Nigrostriatal pathway in the brain which is involved in controlling movement.
Normal neurons of Substantia Nigra
The main content of these Lewy bodies is the protein called Alpha-synuclein which is normally present in the synapses and nuclei of the nerve cells. The over-expression of the gene that encodes for Alpha-synuclein is usually caused by genetic mutation or oxidative stress which blocks the active degradation of this precursor gene. This over-expression leads to abnormal aggregation and deposition of Lewy bodies in the dopaminergic neurons of Sustantia nigra. As a result of this aggregation, these neurons are exposed to inflammatory reactions and eventual cell death and hence cause dysfunctions in mediating movement.
Lewy bodies in the neurons of Substantia Nigra of Parkinson’s patient
One of the most natural solutions to prevent and reduce these neuronal abnormalities is the anti-oxidants. Antioxidants are the compounds that can bind to the free radicals and detoxify them by giving an electron to free oxygen molecules. Antioxidants are naturally present in many fruits and vegetables that are rich sources of Vitamin C, E, Flavonoids and Carotenoids. Researchers have confirmed the positive effect of antioxidants in preventing aging related diseases like Alzheimer’s, Diabetes, and neurodegenerative diseases such as Parkinson’s disease.
It is recommended to have healthy diet of fruits and vegetables such as, grapes, citrus fruits, grapefruit,etc., rather than taking anti-oxidant supplements as the overdose of antioxidants can interfere with normal physiological functions of the reactive oxygen. Hence, it is important to have a healthy diet containing fruits and vegetables and to keep the optimum amount of anti-oxidants in the body in order to slow down aging and related diseases and to prevent other dozens of diseases such as cancer which are induced by oxidative stress.
Link between Parkinson's, Alzheimer's, Free radicals and Anti-oxidants!
