What is PD in Parkinson's disease

summary

What does PD mean in Parkinson's disease? Parkinson's disease (PD) is a common neurodegenerative disease. It is common in the elderly. The average age of onset is about 60 years old. It is rare in young people under 40 years old.

What is PD in Parkinson's disease

Firstly, the incidence rate and prevalence of PD increase with age. PD usually occurs over 60 years old, which suggests that aging is related to the onset of PD. The data show that the number of dopaminergic neurons in substantia nigra of normal adults decreases gradually with age. However, the prevalence of PD is not high in the elderly over 65 years old. Therefore, aging is only one of the risk factors of PD.

Second, the role of genetic factors in the pathogenesis of PD has been paid more and more attention by scholars. Since the discovery of the first Parkinson's disease pathogenic gene α - synuclein (Park1) in the late 1990s, at least six pathogenic genes have been associated with familial Parkinson's disease. But only 5-10% of Parkinson's disease have family history, most of them are sporadic cases. Genetic factors are only one of the causes of PD.

Third: in the 1980s, American scholars such as Langston found that some drug addicts would quickly develop typical Parkinson's disease like symptoms, and they were effective on levodopa preparations. It is found that the synthetic heroin used by drug addicts contains a neurotoxic substance 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). The substance is transformed into highly toxic 1-methyl-4-phenyl-pyridine ion MPP + in the brain and selectively enters into the substantia nigra dopaminergic neurons, which inhibits the activity of mitochondrial respiratory chain complex I and promotes oxidative stress response, leading to the degeneration and death of dopaminergic neurons. Therefore, it is suggested that mitochondrial dysfunction may be one of the pathogenic factors of PD. In the follow-up studies, it was also confirmed that the activity of mitochondrial respiratory chain complex I decreased selectively in substantia nigra of patients with primary PD. The chemical structures of some herbicides and insecticides are similar to MPTP. With the discovery of MPTP, people realized that some MPTP like chemicals in the environment may be one of the pathogenic factors of PD. However, only a small number of drug users exposed to MPTP developed PD, suggesting that PD may be the result of multiple factors.

matters needing attention

In addition to aging and genetic factors, brain injury, smoking, drinking coffee and other factors may also increase or decrease the risk of PD. Smoking is negatively correlated with the occurrence of PD, which has been consistent in many studies. Caffeine has a similar protective effect. Severe brain injury may increase the risk of PD.