The pathology of Parkinson's disease, and how to counteract it - Essay Example

Pathology of Parkinson’s disease Parkinson’s disease commonly referred to as PD is one of the most common neurodegenerative diseases. PD affects mostly the neurons located in the nervous system. The affected neurons located in the basal ganglia cavity get deteriorated affecting the normal functions of the nervous system resulting to rigidity, tremor and bradykinesia. The resulting PD conditions get worse with age making it complicated to treat and control. More studies have to be conducted in an effort to come up with better strategies to counteract the disease. In order to identify different treatment methods, the pathology of the disease has to be understood which has also proved to be a complex process. This paper discusses the pathology and physiology of the PD and how it can be treated using various methods Studies conducted earlier have failed to identify the main factors behind PD irregular form making it almost impossible to come up with a single method of treating the disease. Parkinson’s condition normally affects the dopaminergic cells located in the substania nigra region by altering their normal activity of secreting dopamine. Dopaminergic cells form part of the neural circuits and once the circuit inside the basal ganglia is affected, the process of regulating movement will be inhibited. The movement regulation process involves both the indirect and direct pathways which are responsible for inhibiting and facilitating movement respectively. This implies that when the dopaminergic cells are lost, the disease condition will result in a movement disorder. PD results to the loss of more the 70% of the dopamine cells at its onset which is later followed by dopamine terminals asymmetric loss taking place in the striatum. When a patient is affected by PD, his or her circuitry balance in normally lost. Such loss comes about as a result of dopamine depletion. The parts that are affected in this case are the indirect and direct pathways whose nuclei are responsible for inhibiting the thalamus. When the activities of these nuclei found in the pathways increase, the inhibition process is consequently increased reducing the normal movement of a person. Another conditions resulting to the disease is the degeneration process that takes place in the presence of proteinaceous inclusions, which include; intracytoplasmic and Lewy bodies (LBs) (Blandini 1). The Lewy bodies are located in the brain cells and consist of different types of proteins which after degenerating they give rise to the PD conditions affecting the brain and the nervous system. The LBs can be easily identified when they affect the brain cells as they are spherical in shape with a core that is central and granular with a fibrillary halo surrounding it as shown in figure 1 bellow. The SNC activities are responsible for some of the PD symptoms including movement execution, tremors and muscle rigidity (Blandini 6). Figure 1 showing a Lewy body located in the brain cell (Cuerda 102). The death of Nigral cells is normally facilitated by the presence environmental toxins and the reduced number of Nigral cells consequently results in protein aggregation and mitochondrial defects (Blandini 1). The death of nigral cell is thus one of the main causes of neuron degeneration. Some of the factors leading to nigral cell death through abnormal apoptosis regulation include; impaired mitochondrial activities, proteasomal impairment or glutamate receptors excessive stimulation (Cuerda 102). Several methods of treating and controlling PD have been proposed. Among the many strategies is the L-3, 4-dihydroxyphenylalanine (L-DOPA) which is the oldest and the mostly commonly used (Schapira 102). L-DOPA treatment targets nervous system barrier between the brain and blood forming a reduced section of the brain as shown in the figure bellow. Once in the brain, L-DOPA is converted to the dopamine where it is broken down to form various systems of enzymes in the brain. The agonists produced by dopamine are the ones behind the stimulation process of the nerve receptors in the brain. The nerve receptors stimulation process reduces the symptoms of PD while still at its early stages. Dopamine and Dopaminergic transmission is pharmacological approaches which has been identified as one of treatments of PD. Dopamine are chemical compounds found in the brain involved in learning. When the dopamine transmission levels are increased in the brain as a result of high intake of addictives like cocaine, the dopamine system is stimulated releasing dopamine receptors. Now that dopamine cannot travel across the barrier between brain and blood, the transmission process involves having Levodopa travel across such bounderies after which it is converted to dopamine (Blandini 15). Figure 2 showing areas of brain volume reduction (Schapira 89). Therapeutic strategies can be used in the treatment of PD through employing neuroprotective effects which will reverse, block or hinder the neurodegenerative process. Nueroprotection slows down or in some situations prevents dopaminergic neurons from degenerating thus controlling the disease and reduces the effects of dopamine depletion. Some of the neuroprotective agents used in the prevention process include; dopamine agents, rasagiline and selegiline (Blandini 1). The number of neurons in the body determines the extent at which the disease will affect the patient. Nuerorescue process counters the impact of PD by increasing the number of lost neurons in the nervous system by reversing the neurons metabolic abnormalities (Blandini 5). In the same context of keeping up with the optimum number of neurons in the nervous system, Nuerorestoration can also be used as the process increases the number of dopaminergic neurons still surviving. The cells that have already been damaged by the disease can be replaced through cell transplantation or cell replacement of immature dopaminergic neurons to restore the lost neurons stabilizing the condition of the patient (Blandini 1).Deep brain stimulation (DBS) refers to a surgical procedure used to treat several neurological symptoms, especially the debilitating PD symptoms like stiffness, rigidity, tremor and walking problems (Stewart and Weiner 131). The globus pallidus form the main nucleus hence determines the motor circuit’s functions and can be inactivated through reducing its subthalamic nucleus activity thus controlling the disease extent. An alternative approach to treat PD is by the use of Gene therapy by using a virus that can move a gene into a selected brain part to produce an enzyme which is responsible for managing the symptoms associated with PD. Clinical studies conducted to find out the usefulness of gene therapy in the treatment of PD have identified specific genes such as alpha-synuclein (SNCA), park (PARK2), DJ1 (PARK7), induced putative kinase 1(PINK 1), and PTEN (Stewart and Weiner 130). The SNCA genes have been identified as to result in genetic variations and this forms a risk for idiopathic PD. Considering both LRRK and SNCA genes, SCNA levels of mutation is so low that is inconsequential to PD condition while LRRK has a slight mutation hence influences the form of PD (Stewart and Weiner 133). From the above discussion, it is evident that the pathology of PD is complicated making the treatment and control of the disease a complex task. The complexity of the disease has made it almost impossible for researchers to settle for a single approach of treating and controlling the disease. The neurons being the main causative agents of the disease form the basis of any method that can treat or control the disease. The approaches proposed control the degeneration process of the cells, stop it completely or try to restore the cells. Some of the approaches include; basal ganglia circuitry, dopamine and dopaminergic transmission, L-DOPA, deep brain stimulation, cell replacement/transplantation and neuroprotection. Despite the large number of approaches to counter PD, more studies have to be conducted to come up with more and better methods. Work Cited Blandini, Fabio. “Modeling and remodeling”. The Human Brain. October 6-9, 2004 Blandini, Fabio. “Neuroprotective compounds and innovative therapeutic strategies for Parkinson’s disease: experimental and clinical studies.” Open Access Journal of Clinical Trials. 2009:11-15 Cuerda, Roberto, et al. "Axial Rigidity and Quality of Life in Patients with Parkinson's disease: A Preliminary Study." Quality of Life Research 20.6 (2011): 817-23. ABI/INFORM Complete. Web. 26 Oct. 2012. Factor, Stewart and William Weiner. Parkinson's disease: Diagnosis and Clinical Management. New York, NY: Demos, 2008. Print. Schapira, Anthony. Parkinson's disease. Oxford: Oxford University Press, 2010. Print. Read More