Physiological effects of dual target DBS in an individual with Parkinson's disease and a sensing-enabled pulse generator.

INTRODUCTION: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) or globus pallidus (GP) is an established therapy for Parkinson's disease (PD). Novel DBS devices can record local field potential (LFP) physiomarkers from the STN or GP. While beta (13-30 Hz) and gamma (40-90 Hz) STN and GP LFP oscillations correlate with PD motor severity and with therapeutic effects of treatments, STN-GP interactions in electrophysiology in patients with PD are not well characterized. METHODS: Simultaneous bilateral STN and GP LFPs were recorded in a patient with PD who received bilateral STN-DBS and GP-DBS. Power spectra in each target and STN-GP coherence were assessed in various ON- and OFF-levodopa and DBS states, both at rest and with voluntary movement. RESULTS: OFF-levodopa and OFF-DBS, beta peaks were present at bilateral STN and GP, coincident with prominent STN-GP beta coherence. Levodopa and dual-target-DBS (simultaneous STN-DBS and GP-DBS) completely suppressed STN-GP coherence. Finely-tuned gamma (FTG) activity at half the stimulation frequency (62.5 Hz) was seen in the STN during GP-DBS at rest. To assess the effects of movement on FTG activity, we recorded LFPs during instructed movement. We observed FTG activity in bilateral GP and bilateral STN during contralateral body movements while on GP-DBS and ON-levodopa. No FTG was seen with STN-DBS or dual-target-DBS. CONCLUSION: Dual-target-DBS and levodopa suppressed STN-GP coherence. FTG throughout the basal ganglia was induced by GP-DBS in the presence of levodopa and movement. This bilateral STN-FTG and GP-FTG corresponded with the least severe bradykinesia state, suggesting a pro-kinetic role for FTG.

A2B Adenosine Receptor Enhances Chemoresistance of Glioblastoma Stem-Like Cells under Hypoxia: New Insights into MRP3 Transporter Function.

Glioblastoma is the most common and aggressive primary brain tumor, characterized by its high chemoresistance and the presence of a cell subpopulation that persists under hypoxic niches, called glioblastoma stem-like cells (GSCs). The chemoresistance of GSCs is mediated in part by adenosine signaling and ABC transporters, which extrude drugs outside the cell, such as the multidrug resistance-associated proteins (MRPs) subfamily. Adenosine promotes MRP1-dependent chemoresistance under normoxia. However, adenosine/MRPs-dependent chemoresistance under hypoxia has not been studied until now. Transcript and protein levels were determined by RT-qPCR and Western blot, respectively. MRP extrusion capacity was determined by intracellular 5 (6)-Carboxyfluorescein diacetate (CFDA) accumulation. Cell viability was measured by MTS assays. Cell cycle and apoptosis were determined by flow cytometry. Here, we show for the first time that MRP3 expression is induced under hypoxia through the A2B adenosine receptor. Hypoxia enhances MRP-dependent extrusion capacity and the chemoresistance of GSCs. Meanwhile, MRP3 knockdown decreases GSC viability under hypoxia. Downregulation of the A2B receptor decreases MRP3 expression and chemosensibilizes GSCs treated with teniposide under hypoxia. These data suggest that hypoxia-dependent activation of A2B adenosine receptor promotes survival of GSCs through MRP3 induction.

Pituitary Apoplexy: Results of Surgical and Conservative Management Clinical Series and Review of the Literature.

OBJECTIVE: Pituitary apoplexy is associated with visual, cranial nerve, and endocrine dysfunction. In this article, the results of surgical and conservative management of pituitary apoplexy in a single center are evaluated and a review of the literature is presented. METHODS: A retrospective analysis was made of patients with pituitary apoplexy who underwent surgery or conservative management at our center between January 2007 and June 2017. Surgery was typically selected for patients who presented with acute deterioration of visual status and/or level of consciousness. Patients with no visual field deficit and those who had medical contraindications to undergo a surgical procedure because of previous comorbidities typically had conservative treatment. Baseline characteristics and clinical and radiologic outcomes were reviewed. A review of the literature (1990-2018) was performed according to PRISMA guidelines. Studies comparing the results of conservative and surgical management were identified. Visual, cranial nerve, and endocrine outcomes and tumor recurrence were analyzed. RESULTS: Forty-nine patients (73.1%) were managed surgically and 18 (26.9%) conservatively. After careful case selection, patients underwent surgical or conservative treatment. Patients who underwent conservative treatment had fewer visual deficits. At diagnosis, visual deficit (38.8% vs. 75.5%; P = 0.008) and cranial nerve palsy (27.7% vs. 51%; P = 0.058) were less common in the conservative group. Conservative and surgical treatments had similar visual and cranial nerve improvement rates (75% vs. 58.3%, P = 0.63 and 75% vs. 69.2%, P = 1.0, respectively). In the conservative group, tumor shrinkage was observed in 76.4% of cases. The systematic review retrieved 11 studies. No significant difference between conservative and surgical treatment for clinical outcomes (visual field recovery, odds ratio [OR], 1.45; 95% confidence interval [CI], 0.72-2.92; cranial nerve recovery, OR, 2.30; 95% CI, 0.93-5.65; and hypopituitarism, OR, 1.05; 95% CI, 0.64-1.74) or tumor recurrence (OR, 0.68; 95% CI, 0.20-2.34) was observed. CONCLUSIONS: A tailored approach to pituitary apoplexy, one that does not include an absolute need for surgery, is appropriate. Conservative management is appropriate in selected patients presenting without visual deficits.

Relationship between infarct size and serum uric acid levels during the acute phase of stroke.

INTRODUCTION: Uric acid has gained considerable attention as a potential neuroprotective agent in stroke during the last decades, however, its role in the pathophysiology of ischemic stroke remains poorly understood. A serial evaluation of uric acid levels during the acute phase of stroke and its association with infarct size on magnetic resonance imaging is lacking. METHODS: We present a cohort study of 31 patients with ischemic stroke who were not candidates for thrombolysis according to current criteria at the time. We performed daily measurements of serum uric acid and total antioxidant capacity of plasma during the first week after symptoms onset and 30 days after. Infarct size was determined in the acute phase by a DWI sequence and the final infarct size with a control MRI (FLAIR) at day 30. RESULTS: Uric acid significantly decreases between days 2 to 6 compared to day 1, after adjustment by sex, age and DWI at diagnosis, with a nadir value at 72h. A mixed model analysis showed a negative association between DWI at diagnosis and uric acid evolution during the first week after stroke. Moreover, multivariable linear regression of uric acid values during follow up on DWI volumes demonstrated that DWI volume at diagnosis is negatively associated with uric acid levels at day 3 and 4. There were no significant associations between total antioxidant capacity of plasma and DWI at diagnosis, or FLAIR at any point. DISCUSSION: Patients with larger infarcts exhibited a significant decrease in serum uric acid levels, accounting for a more prominent reactive oxygen species scavenging activity with subsequent consumption and decay of this antioxidant. The different kinetics of total antioxidant capacity of plasma and serum uric acid levels suggests a specific role of uric acid in the antioxidant response in ischemic stroke.

Ethmoid Meningoencephalocele in a Patient with Cerebrofacial Arteriovenous Metameric Syndrome.

BACKGROUND: Skull base meningoencephaloceles are a rare condition, frequently secondary to traumatic or iatrogenic causes. Cerebrofacial arteriovenous metameric syndrome (CAMS) is characterized by the presence of retinal, facial, and cerebral arteriovenous malformations (AVMs) with metameric distribution. To our knowledge, this is the first reported case associating these 2 conditions. CASE DESCRIPTION: A 45-year-old woman previously diagnosed with CAMS type 2 presented with a long history of cerebrospinal fluid (CSF) rhinorrhea. Magnetic resonance imaging and digital subtraction angiography demonstrated a right-sided facial and orbital AVM extending posteriorly along the optic tract into the suprasellar cistern, and a right-sided meningoencephalocele protruding into the olfactory recess and ethmoid sinus. An extended endoscopic endonasal approach was performed to resect the meningoencephalocele and to repair the CSF leak without complications. CONCLUSIONS: We report the unusual association between the development of a meningoencephalocele and a metameric syndrome, and comment on clinical implications in the management of this patient.

Novel therapeutic strategies for traumatic brain injury: acute antioxidant reinforcement.

Traumatic brain injury (TBI) is the most important cause of disability in individuals under the age of 45 years and thus represents a significant social and economic burden. Evidence strongly suggests that oxidative stress is a cornerstone event leading to and propagating secondary injury mechanisms such as excitotoxicity, mitochondrial dysfunction, apoptosis, autophagy, brain edema, and inflammation. TBI has defied conventional approaches to diagnosis and therapy development because of its heterogeneity and complexity. Therefore, it is necessary to explore alternative approaches to therapy development for TBI. The aim of this review is to present a therapeutic approach for TBI, taking into account the evidence supporting the role for oxidative stress in the pathophysiological processes of secondary brain injury. The role of agents such as mitochondria-targeted antioxidants (melatonin and new mitochondria-targeted antioxidants), nicotinamide adenine dinucleotide phosphate (NADPH) inhibitors (antioxidant vitamins and apocynin), and other compounds having mainly antioxidant properties (hydrogen-rich saline, sulforaphane, U-83836E, omega-3, and polyphenols) is covered. The rationale for innovative antioxidant therapies based on current knowledge and particularly the most recent studies regarding this field is discussed. Particular considerations and translational potential of new TBI treatments are examined and a novel therapeutic proposal for TBI is presented.

Oxidative stress and pathophysiology of ischemic stroke: novel therapeutic opportunities.

Stroke is the second leading cause of death, after ischemic heart disease, and accounts for 9% of deaths worldwide. According to the World Health Organization [WHO], 15 million people suffer stroke worldwide each year. Of these, more than 6 million die and another 5 million are permanently disabled. Reactive oxygen species [ROS] have been implicated in brain injury after ischemic stroke. There is evidence that a rapid increase in the production of ROS immediately after acute ischemic stroke rapidly overwhelm antioxidant defences, causing further tissue damage. These ROS can damage cellular macromolecules leading to autophagy, apoptosis, and necrosis. Moreover, the rapid restoration of blood flow increases the level of tissue oxygenation and accountsfor a second burst of ROS generation, which leads to reperfusion injury. Current measures to protect the brain against severe stroke damage are insufficient. Thus, it is critical to investigate antioxidant strategies that lead to the diminution of oxidative injury. The antioxidant vitamins C and E, the polyphenol resveratrol, the xanthine oxidase [XO] inhibitor allopurinol, and other antioxidant strategies have been reviewed in the setting of strokes. This review focuses on the mechanisms involved in ROS generation, the role of oxidative stress in the pathogenesis of ischemic stroke, and the novel therapeutic strategies to be tested to reduce the cerebral damage related to both ischemia and reperfusion.