A New Window for the Treatment of Posterior Cerebral Artery, Superior Cerebellar Artery, and Basilar Apex Aneurysm: The Expanded Endoscopic Endonasal Approach

To explore the feasibility of an endoscopic endonasal transclival approach to treat aneurysms arising in the basilar apex, posterior cerebral arteries, and superior cerebellar arteries

Using the Endoscopic Endonasal Transclival Approach to Access Aneurysms Arising from AICA, PICA, and Vertebral Artery: An Anatomical Study

Objective To explore the use of the endoscopic endonasal transclival approach (EEA) for clipping anterior inferior cerebellar artery (AICA), posterior inferior cerebellar artery (PICA), and vertebral artery (VA) aneurysms

Neocortex and allocortex respond differentially to cellular stress in vitro and aging in vivo.

In Parkinson's and Alzheimer's diseases, the allocortex accumulates aggregated proteins such as synuclein and tau well before neocortex. We present a new high-throughput model of this topographic difference by microdissecting neocortex and allocortex from the postnatal rat and treating them in parallel fashion with toxins. Allocortical cultures were more vulnerable to low concentrations of the proteasome inhibitors MG132 and PSI but not the oxidative poison H2O2. The proteasome appeared to be more impaired in allocortex because MG132 raised ubiquitin-conjugated proteins and lowered proteasome activity in allocortex more than neocortex. Allocortex cultures were more vulnerable to MG132 despite greater MG132-induced rises in heat shock protein 70, heme oxygenase 1, and catalase. Proteasome subunits PA700 and PA28 were also higher in allocortex cultures, suggesting compensatory adaptations to greater proteasome impairment. Glutathione and ceruloplasmin were not robustly MG132-responsive and were basally higher in neocortical cultures. Notably, neocortex cultures became as vulnerable to MG132 as allocortex when glutathione synthesis or autophagic defenses were inhibited. Conversely, the glutathione precursor N-acetyl cysteine rendered allocortex resilient to MG132. Glutathione and ceruloplasmin levels were then examined in vivo as a function of age because aging is a natural model of proteasome inhibition and oxidative stress. Allocortical glutathione levels rose linearly with age but were similar to neocortex in whole tissue lysates. In contrast, ceruloplasmin levels were strikingly higher in neocortex at all ages and rose linearly until middle age. PA28 levels rose with age and were higher in allocortex in vivo, also paralleling in vitro data. These neo- and allocortical differences have implications for the many studies that treat the telencephalic mantle as a single unit. Our observations suggest that the topographic progression of protein aggregations through the cerebrum may reflect differential responses to low level protein-misfolding stress but also reveal impressive compensatory adaptations in allocortex

Correction: Neocortex and Allocortex Respond Differentially to Cellular Stress In Vitro and Aging In Vivo

In Parkinson’s and Alzheimer’s diseases, the allocortex accumulates aggregated proteins such as synuclein and tau well before neocortex. We present a new high-throughput model of this topographic difference by microdissecting neocortex and allocortex from the postnatal rat and treating them in parallel fashion with toxins. Allocortical cultures were more vulnerable to low concentrations of the proteasome inhibitors MG132 and PSI but not the oxidative poison H(2)O(2). The proteasome appeared to be more impaired in allocortex because MG132 raised ubiquitin-conjugated proteins and lowered proteasome activity in allocortex more than neocortex. Allocortex cultures were more vulnerable to MG132 despite greater MG132-induced rises in heat shock protein 70, heme oxygenase 1, and catalase. Proteasome subunits PA700 and PA28 were also higher in allocortex cultures, suggesting compensatory adaptations to greater proteasome impairment. Glutathione and ceruloplasmin were not robustly MG132-responsive and were basally higher in neocortical cultures. Notably, neocortex cultures became as vulnerable to MG132 as allocortex when glutathione synthesis or autophagic defenses were inhibited. Conversely, the glutathione precursor N-acetyl cysteine rendered allocortex resilient to MG132. Glutathione and ceruloplasmin levels were then examined in vivo as a function of age because aging is a natural model of proteasome inhibition and oxidative stress. Allocortical glutathione levels rose linearly with age but were similar to neocortex in whole tissue lysates. In contrast, ceruloplasmin levels were strikingly higher in neocortex at all ages and rose linearly until middle age. PA28 levels rose with age and were higher in allocortex in vivo, also paralleling in vitro data. These neo- and allocortical differences have implications for the many studies that treat the telencephalic mantle as a single unit. Our observations suggest that the topographic progression of protein aggregations through the cerebrum may reflect differential responses to low level protein-misfolding stress but also reveal impressive compensatory adaptations in allocortex

A New Window for the Treatment of Posterior Cerebral Artery, Superior Cerebellar Artery, and Basilar Apex Aneurysm: The Expanded Endoscopic Endonasal Approach

OBJECTIVE:  To explore the feasibility of an endoscopic endonasal transclival approach to treat aneurysms arising in the basilar apex, posterior cerebral arteries, and superior cerebellar arteries. STUDY DESIGN:  Cadaveric anatomical study. PARTICIPANTS:  Fifteen cadaveric specimens. MAIN OUTCOME MEASURES:  Degree of surgical exposure of each artery attained, distance from the nasal vestibule to these three arteries, and feasibility of clipping these vessels using standard vascular clip applicators. RESULTS:  Both posterior cerebral arteries were exposed, 0.67 cm (standard deviation [SD]: 0.2) on the right side and 0.59 cm (SD: 0.2) on the left side. Both right and left superior cerebral arteries were exposed, 0.6 cm (SD: 0.2) and 0.7 cm (SD: 0.3), respectively. The length of the basilar artery exposed was 2.6 cm (SD: 0.3). The distance from the nasal vestibule to the posterior cerebral artery, superior cerebellar artery, and basilar apex was 10 cm with an SD of ± 0.7, 0.6, and 0.8 cm, respectively. We were able to apply clips on each of these three vessels with a minimal alteration of surrounding normal tissue. CONCLUSION:  The endoscopic endonasal transclival approach represents a potentially feasible surgical corridor to treat aneurysms arising from these vessels

Impact of natural aging on neocortex and allocortex <i>in vivo</i>.

<p><b>A:</b> Glutathione levels in whole tissue lysates of rat neo- and allocortex as a function of age. Allocortical glutathione levels were similar to those in neocortex but rose in an age-dependent manner and were significantly higher at 19–22 months of age relative to the youngest group (2–4 months). Neocortical glutathione did not change significantly as a function of age. <b>B–C:</b> Western immunoblotting for ceruloplasmin as a function of age and brain region. Neocortex had much more ceruloplasmin than allocortex at every age examined. Furthermore, neocortical ceruloplasmin rose in an age-dependent manner until rats were 16–19 months old. <b>D–E:</b> PA28 levels as a function of age in neo- and allocortex. PA28 levels rose in neocortex at 19–22 months and in allocortex at 16–19 months relative to the youngest age group. Allocortical PA28 levels were significantly higher than in neocortex at 16–19 months of age. Data are expressed as mean and standard error of the mean from 4–5 rats per group. For all panels, **<i>p</i> ≤ 0.01, ***<i>p</i> ≤ 0.001, allocortex versus neocortex;+<i>p</i> ≤ 0.05,+++<i>p</i> ≤ 0.001 versus levels in the 2–4 month old group; Bonferroni <i>post hoc</i> correction following two-way ANOVA.</p

Role of glutathione in protection of neo- and allocortex against proteasome inhibition.

<p><b>A:</b> Glutathione (GSH) levels as a function of total MAP2 levels in neocortex and allocortex in the presence or absence of MG132. Allocortical cells exhibited less glutathione than neocortical cells in both conditions <i>in vitro</i>. <b>B–C:</b> MAP2 levels (<b>B</b>) and glutathione levels (<b>C</b>) as a function of indicated concentrations of buthionine sulfoximine (BSO). Neocortical cells exhibited much greater glutathione loss with buthionine sulfoximine than allocortical cells. Buthionine sulfoximine was not lethal to neurons at the indicated concentrations. <b>D–E:</b> Neocortical and allocortical neurons were treated with vehicle or MG132 (0.25 µM) and vehicle or buthionine sulfoximine (12.5 µM). Both allocortical neurons and neocortical neurons were more vulnerable to combined treatment with buthionine sulfoximine and MG132 than either toxin alone (<b>D</b>). The glutathione assay revealed again that neocortical cells lost more glutathione with buthionine sulfoximine than allocortical cells, but that allocortical cells had overall less glutathione than neocortical cells in all four groups (<b>E</b>). <b>F–G</b>: N-acetyl cysteine (3 mM) completely prevented the toxicity of 0.25 µM MG132 in allocortical cultures (<b>F</b>) and considerably raised glutathione levels both with and without MG132 on board (<b>G</b>). Shown are the mean and standard error of the mean of at least 3 independent experiments. For all panels, *<i>p</i> ≤ 0.05, **<i>p</i> ≤ 0.01, ***<i>p</i> ≤ 0.001, or ****<i>p</i> ≤ 0.0001 allocortex versus neocortex; ^∧<i>p</i> ≤ 0.05, ^∧∧<i>p</i> ≤ 0.01, ^∧∧∧<i>p</i> ≤ 0.001, or ^∧∧∧∧<i>p</i> ≤ 0.0001 MG132 versus vehicle;+<i>p</i> ≤ 0.05,++<i>p</i> ≤ 0.01,+++<i>p</i> ≤ 0.001,++++<i>p</i> ≤ 0.0001 buthionine sulfoximine versus water or N-acetyl cysteine versus water; Bonferroni <i>post hoc</i> correction following two-way ANOVA.</p

Involvement of autophagic defenses and ubiquitin-proteasome system.

<p><b>A–B</b>: Infrared Western immunoblotting for macroautophagy-related molecule Beclin 1 following treatment of neo- and allocortical cultures with 0.25 and 1 µM MG132 is shown. β-actin was used as a loading control. <b>C–D</b>: Ammonium chloride (20 mM NH₄Cl) was used to inhibit all forms of autophagy and wortmannin (50 nM) was used to inhibit macroautophagy in neo- and allocortical cultures subjected to vehicle or 0.25 µM MG132. Neocortical neurons became as vulnerable to MG132 as allocortical neurons in response to NH₄Cl. Wortmannin failed to elicit an effect. Shown are the mean and standard error of the mean of at least 3 independent experiments. *<i>p</i> ≤ 0.05, **<i>p</i> ≤ 0.01, ***<i>p</i> ≤ 0.001 allocortex vs neocortex; ^∧<i>p</i> ≤ 0.05 or ^∧∧∧<i>p</i> ≤ 0.001 MG132 vs vehicle; +<i>p</i> ≤ 0.05 NH₄Cl versus vehicle; Bonferroni <i>post hoc</i> correction following two-way ANOVA. <b>E–F:</b> Infrared Western immunoblotting for ubiquitin-conjugated proteins revealed that allocortex exhibited higher levels of this measure of proteotoxic stress in response to MG132. <b>G:</b> Proteasome activity was measured in the presence or absence of MG132 in a fluorogenic assay. Allocortical proteasomes were more inhibited by MG132 than those from neocortex. Shown are the mean and standard error of the mean of at least 3 independent experiments. For F and G, *<i>p</i> ≤ 0.05, **<i>p</i> ≤ 0.01 allocortex versus neocortex;+<i>p</i> ≤ 0.05,+++<i>p</i> ≤ 0.001,++++<i>p</i> ≤ 0.0001 MG132 versus vehicle (0 µM MG132); Bonferroni <i>post hoc</i> correction following two-way ANOVA.</p

Characterization of <i>in vitro</i> model.

<p><b>A–F:</b> Neocortical and allocortical tissue was microdissected from postnatal rat brains, dissociated, and plated in 96-well plates at 100,000 cells per well. Cells were treated with 2.5 µM cytosine arabinofuranoside to suppress, but not eliminate, glial proliferation on day in vitro 2 (DIV2). Plates were immunostained on DIV4 for the neuronal marker microtubule associated protein 2 (MAP2, shown in red). Nuclei were stained blue with Hoechst. Merged images reveal that the majority of the Hoechst-stained nuclei were neuronal. However, arrowheads point to large nuclei that were possibly glial. Long stemmed arrows point to condensed, potentially apoptotic nuclei that may have lost their neuronal phenotype. <b>G:</b> Blind cell counts revealed that nearly 75% of neocortical and allocortical Hoechst-positive cells expressed the MAP2 neuronal phenotype. <b>H and I:</b> Basal survival on DIV4 was measured by an infrared In-Cell Western assay for MAP2 and by the Cell Titer Glo assay for ATP. Both assays revealed that allocortex survived <i>in vitro</i> conditions at approximately twice the rate of neocortex. A grayscale inset of a representative infrared MAP2 stain of neo- versus allocortical neurons is included in <b>H.</b> Shown are the mean and standard error of the mean of at least 3 independent experiments. **<i>p</i> ≤ 0.01 or ***<i>p</i> ≤ 0.001 by the two tailed <i>t</i>-test. <b>J:</b> Brains were fixed following tissue dissections, cut in the sagittal plane, and stained for the infrared nuclear marker DRAQ5. Neocortical dissections (arrow) were centered in primary motor and sensory cortex (Ctx), dorsal to hippocampus (HP) and caudoputamen (CP). Allocortical dissections (arrow) were centered much more laterally in the brain ventral to hippocampus in the entorhinal and piriform cortices.</p