Neurosurgery for Parkinson's disease

Resveratrol delays 6-hydroxydopamine-induced apoptosis by activating the PI3K/Akt signaling pathway

This study aimed to determine whether resveratrol (Res) delays the progression of 6-hydroxydopamine (6-OHDA)-induced apoptosis via activating the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway. Sprague-Dawley (SD) rats were unilaterally injected with 6-OHDA (8 μg/4 μL) into the substantia nigra of the midbrain. Res (15 and 30 mg/kg) was given orally to the rats for a total of 36 days to examine its protective effects. We first tested whether Res can delay the progression of 6-OHDA-induced damage by measuring weight and performance on behavioral tests (rotarod, open field test and grid test) and further explored whether this effect is related to the activation of the PI3K/Akt signaling pathway using immunohistochemistry (IHC) and Western blotting (WB). Our results showed that the damage induced by 6-OHDA gradually worsened, while Res 30 mg/kg treatment significantly improved motor function and increased body weight. Compared with those in the model group, the number of dopaminergic neurons cells and the expression of PI3K-110α, p-Akt Ser473, and pro-caspase-3 in the Res 30 mg/kg group were significantly increased, and the Bax/Bcl-2 ratio and the level of activated caspase-3 was decreased. The results indicate that Res ameliorates 6-OHDA-induced apoptosis and motor dysfunction via activating the PI3K/Akt signaling pathway, delaying the progression of Parkinson's disease (PD) symptoms in this model.

Parkinson's disease and anaesthesia

Parkinson's disease (PD), one of the most common disabling neurological diseases, affects about 1% of the population over 60 years of age. It is a degenerative disease of the central nervous system caused by the loss of dopaminergic fibers in basal ganglia of the brain. PD is an important cause of perioperative morbidity and with an increasingly elderly population, it is being encountered with greater frequency in surgical patients. Particular anaesthetic problems in PD include old age, antiparkinsonian drug interaction with anaesthetic drugs and various alterations in the respiratory, cardiovascular, autonomic, and neurological systems. This brief review focuses on the preoperative, intraoperative, and postoperative anesthetic management of PD and gives a brief account of intraoperative exacerbation of PDs and anesthetic management of stereotactic pallidotomy.

Advances in the treatment of Parkinson's disease

Parkinson's disease (PD) affects one in every 100 persons above the age of 65 years, making it the second most common neurodegenerative disease after Alzheimer's disease. PD is a disease of the central nervous system that leads to severe difficulties with body motions. The currently available therapies aim to improve the functional capacity of the patient for as long as possible; however they do not modify the progression of the neurodegenerative process. The need for newer and more effective agents is consequently receiving a great deal of attention and consequently being subjected to extensive research. This review concisely compiles the limitations of currently available therapies and the most recent research regarding neuroprotective agents, antioxidants, stem cell research, vaccines and various surgical techniques available and being developed for the management of PD.

Subthalamic stimulation for Parkinson disease: determination of electrode location necessary for clinical efficacy

Object

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) performed using intraoperative microelectrode recording (MER) to adjust electrode placement has become a widely used treatment for patients with advanced Parkinson disease (PD). Few studies have been conducted to examine the location of implanted electrodes relative to the intended target, and even fewer have been undertaken to investigate the degree to which variations in the location of these electrodes impacts their clinical efficacy. This study was performed to examine these issues.

Methods

The authors located 52 bilaterally implanted DBS electrode tips on postoperative magnetic resonance (MR) images obtained in 26 consecutive patients. Postoperative and preoperative planning MR images were merged to determine the DBS electrode tip coordinates relative to the midcommissural point. Surgical records listed the intended target coordinates for each DBS electrode tip. Clinical outcome assessment included the Unified PD Rating Scale (UPDRS) motor score at 1 year, standardized questionnaires, and routine follow-up visits.

The mean difference between electrode tip location and intended target for all 52 electrodes was less than 2 mm in all axes. Only one electrode was farther than 3 mm from the intended target, and this was the only electrode that had to be replaced due to lack of clinical efficacy (lack of tremor suppression); its reimplantation 4 mm more medially provided excellent tremor control. High correlation coefficients indicate that the MR imaging analysis accurately determined the anatomical location of the electrode tips. Blinded videotape reviews of UPDRS motor scores comparing effects of stimulation in patients who were “on” and “off” medication identified subgroups in whom there was minimal and maximal stimulation response. Patients in these subgroups had no differences between the MR imaging–determined actual electrode tip location and its intended location. Similarly, improvements of dyskinesias and severity of symptoms encountered during the wearing-off period for the drug did not correlate with variations of electrode tip location.

Conclusions

The findings in this study lead the authors to suggest that a DBS electrode placed anywhere within a 6-mm-diameter cylinder centered at the presumed middle of the STN (based on stereotactic atlas coordinates) provides similar clinical efficacy. Future studies may be warranted to evaluate prospectively the degree to which MER modification of the anatomically and/or image-determined target improves clinical efficacy of DBS electrodes.

A waitlist control-group study of cognitive, mood, and quality of life outcome after posteroventral pallidotomy in Parkinson disease

OBJECT

The aim of this study was to examine neuropsychological outcome from unilateral posteroventral pallidotomy (PVP) in Parkinson disease while controlling for confounding factors such as test practice and disease progression.

METHODS

Participants underwent baseline and 2-month follow-up assessments of cognition, quality of life, mood, and motor functioning. The surgery group (22 patients) underwent PVP (15 left, seven right) after baseline assessment. The waitlist group (14 patients) underwent PVP after follow up. At follow up, the left PVP group exhibited a decline on verbal measures of learning, fluency, working memory, and speeded color naming. The incidence of significant decline on these measures after left PVP ranged from 50 to 86%. The right PVP group did not exhibit a significant cognitive decline, but fluency did decline in 71% of patients who underwent right PVP. Participants who underwent PVP reported better bodily pain and social functioning at follow up than participants in the waitlist group. Improved bodily pain was evident for 62% of the surgery group, and social functioning improved for 19%. Surgery did not alter reported physical functioning or mood. Dyskinesia improved after surgery, but there were no improvements in "on-state" manual dexterity or handwriting.

CONCLUSIONS

Most patients who underwent left PVP exhibited declines in learning, fluency, working memory, and speeded color naming. Accounting for retesting effects altered the magnitude of these declines by up to one quarter of a standard deviation, but did not increase the breadth of postsurgical neuropsychological decline beyond that typically reported in the literature. It was found that PVP improved dyskinesia, bodily pain, and social functioning, but did not lead to improvement on other objective and self-reported measures of motor functioning.

Restorative neurosurgery

Restorative neurosurgery currently is the frontier of neuroscientists for the restoration of lost neuronal function especially in neurodegenerative diseases and ischemic and traumatic central nervous system (CNS) disorders. The striking developments in molecular neurobiology and bio-technology are progressively offering new opportunities for a better quality of life to patients suffering from loss of neuronal function. Besides all new and challenging medical therapeutic interventions, great emphasis is also given to transplantation for neuronal restoration as well.

Parkinson's disease and anaesthesia

Parkinson's disease is an increasingly common disease of elderly patients who present a particular anaesthetic challenge. This review explores the epidemiology, aetiology, pathogenesis, and pathophysiology of the condition, particularly the possible role of genetic factors. The clinical features are described in detail and recent advances in medical management are highlighted. Controversies surrounding the use of the newer drugs and possible advances in neurosurgical interventions are discussed. Particular anaesthetic problems in patients with Parkinson's disease are respiratory, cardiovascular, and neurological. Potential drug interactions are described and recommendations are made about suitable anaesthetic techniques.

Antioxidants as treatment for neurodegenerative disorders

Oxidative stress is a ubiquitously observed hallmark of neurodegenerative disorders. Neuronal cell dysfunction and cell death due to oxidative stress may causally contribute to the pathogenesis of progressive neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease, as well as acute syndromes of neurodegeneration, such as ischaemic and haemorrhagic stroke. Neuroprotective antioxidants are considered a promising approach to slowing the progression and limiting the extent of neuronal cell loss in these disorders. The clinical evidence demonstrating that antioxidant compounds can act as protective drugs in neurodegenerative disease, however, is still relatively scarce. In the following review, the available data from clinical, animal and cell biological studies regarding the role of antioxidant neuroprotection in progressive neurodegenerative disease will be summarised, focussing particularly on Alzheimer's disease, Parkinson's disease, Huntington's disease and amyotrophic lateral sclerosis. The general complications in developing potent neuroprotective antioxidant drugs directed against these long-term degenerative conditions will also be discussed. The major challenges for drug development are the slow kinetics of disease progression, the unsolved mechanistic questions concerning the final causalities of cell death, the necessity to attain an effective permeation of the blood-brain barrier and the need to reduce the high concentrations currently required to evoke protective effects in cellular and animal model systems. Finally, an outlook as to which direction antioxidant drug development and clinical practice may be leading to in the near future will be provided.