Parkinson’s Disease Causes – The causes of Parkinson’s disease are not well understood. But it appears to result from several risk factors. Exposure to unknown environmental toxicants, toxic endogenous compounds, and genetic alterations are thougt as the risk factors of Parkinson’s disease.
Mitochondria and Oxidative Stress in Parkinson’s disease
Both mitochondria and oxidative stress play a crucial role in the pathogenesis of Parkinson’s disease. Many studies have shown that cell death appear to be involved in the deteriorating of dopaminergic neurons, and mitochondria and oxidative stress play key roles in initiating these cell death process. Mitochondria is an organelle placed in all cells in our bodies. They are basically our energy sources.
During this energy producing
Process oxygen is used and in the end of some particular reactions “Reactive oxygen species (also called prooxidants)” are produced within the respiratory chain of the mitochondria. Superoxide, peroxynitrate and hydrogen peroxide are reactive oxygen species. They have a capacity to oxidize and damage a variety of cellular constituents including lipids, DNA, and proteins. But fortunately we have natural fighting systems that combat these reactive oxygen species in our mitochondries. This system is named antioxidant system. Antioxidant system is divided into enzymatic and nonenzymatic groups.
The nonenzymatic antioxidants include the lipid-soluble vitamins such as vitamin E and vitamin A or provitamin A (beta-carotene), and the water-soluble vitamin C. Free radicals are also produced continuously in cells either as by-products of metabolism.
Oxidative stress is the harmful condition that occurs when there is an excess of reactive oxygen species, a decrease in antioxidant levels, or both. It is clear that oxidative stress is an important risk factor of Parkinson’s disease and plays an important role in the pathogenesis of the disease. Neuronal deterioration in the substantia nigra is thought to be due to the accumulation of free radicals. These free radicals react with surrounding cells through oxidation, causing neuronal degeneration. This neuronal degeneration, especially in the substantia nigra, is the cause of Parkinson’s disease.
Mitochondrial Mutations in Parkinson’s disease
Another risk factor of Parkinson’s disease is mithocondrial mutations. Recent surveys of individuals with familial Parkinson’s disease have shown that mutations in three of five known genes linked to Parkinson’s disease are associated with mitochondrial impairment and decreased resistance to oxidative stress. As we mentioned before increased oxidative stress is an important risk factor of Parkinson’s disease.