The blood labyrinthine barrier in the human normal and Meniere's disease macula utricle.

The ultrastructural organization of the blood labyrinthine barrier (BLB) was investigated in the human vestibular endorgan, the utricular macula, using postmortem specimens from individuals with documented normal auditory and vestibular function and surgical specimens from patients with intractable Meniere's disease. Transmission electron microscopic analysis of capillaries located in the normal human utricular stroma showed vascular endothelial cells with few pinocytotic vesicles, covered by a smooth and uniform basement membrane surrounded by pericyte processes. Meniere's disease specimens revealed differential ultrastructural pathological changes in the cellular elements of the microvasculature. With moderate degeneration of the BLB, there were numerous vesicles within the vascular endothelial cells (VECs), with increased numbers at the abluminal face, pericyte process detachment and disruption of the perivascular basement membrane surrounding the VECs. With severe degeneration of the BLB, there was severe vacuolization or frank apparent necrosis of VECs and loss of subcellular organelles. A higher severity of BLB degenerative changes was associated with a higher degree of basement membrane thickening and edematous changes within the vestibular stroma. This study presents the first ultrastructural analysis of the capillaries constituting the BLB in the human vestibular macula utricle from normal and Meniere's disease

Ezrin and Moesin Expression Within the Developing Human Cerebrum and Tuberous Sclerosis-Associated Cortical Tubers.

The ERM (ezrin, radixin, and moesin) proteins belong to the band-4.1 superfamily of membrane-cytoskeleton-linking proteins which bind to the actin cytoskeleton via their C-terminal sequences and bind ERM binding membrane proteins (ERMBMPs). We investigated the immunohistochemical expression of two of the ERM proteins (ezrin and moesin) in developing human cerebral cortex and in cortical tubers from patients with tuberous sclerosis (TSC), to assess possible consequences of TSC gene product malfunction or inactivation in the developing brain in relation to ERM protein expression. Ezrin is abundantly expressed within radial glia and migrating cells in the intermediate zone in the prenatal human cerebrum, while moesin is primarily expressed in vascular endothelial cells in developing and adult human brain and scattered microglia in adult brain. In addition, both ezrin and moesin are abundantly co-expressed with hamartin and tuberin within a population of abnormal cells in TSC-associated cortical tubers. The expression of these two proteins--primarily ezrin--suggests that they are developmentally regulated and abundantly expressed in germinal matrix and/or migrating cells during cerebral cortical development. In TSC-associated cortical tubers, both proteins appeared to be up-regulated and are co-localized within a population of abnormal neuroglial cells typical of those seen in tubers. Expression of these proteins and their co-localization with tuberin and hamartin in these cells may suggest a compensatory up-regulation in response to TSC gene mutation

Cellular antiseizure mechanisms of everolimus in pediatric tuberous sclerosis complex, cortical dysplasia, and non-mTOR-mediated etiologies.

The present study was designed to examine the potential cellular antiseizure mechanisms of everolimus, a mechanistic target of rapamycin (mTOR) pathway blocker, in pediatric epilepsy cases. Cortical tissue samples obtained from pediatric patients (n = 11, ages 0.67-6.75 years) undergoing surgical resections for the treatment of their pharmacoresistant epilepsy were examined electrophysiologically in ex vivo slices. The cohort included mTOR-mediated pathologies (tuberous sclerosis complex [TSC] and severe cortical dysplasia [CD]) as well as non-mTOR-mediated pathologies (tumor and perinatal infarct). Bath application of everolimus (2 μm) had practically no effect on spontaneous inhibitory postsynaptic activity. In contrast, long-term application of everolimus reduced spontaneous excitatory postsynaptic activity, burst discharges induced by blockade of γ-aminobutyric acid A (GABAA) receptors, and epileptiform activity generated by 4-aminopyridine, a K+ channel blocker. The antiseizure effects were more pronounced in TSC and CD cases, whereas in non-mTOR-mediated pathologies, the effects were subtle at best. These results support further clinical trials of everolimus in mTOR pathway-mediated pathologies and emphasize that the effects require sustained exposure over time

Residual Tumor Confers a 10-Fold Increased Risk of Regrowth in Clinically Nonfunctioning Pituitary Tumors.

ObjectiveWe evaluated tumor recurrence and regrowth rates following endoscopic transnasal transsphenoidal (TNTS) surgical removal in a consecutive series of clinically nonfunctioning pituitary adenomas (CNFTs).DesignRetrospective chart review of clinical, biochemical, and sellar MRI findings in all TNTS surgeries in patients with CNFT, performed by a single surgeon, between 2008 and 2015 (n = 280).PatientsNinety-three patients met eligibility criteria, with complete clinical, biochemical, and imaging follow-up for a 3-year minimum.ResultsOf 85 patients who were not irradiated, 3-month postsurgical MRI demonstrated no residual tumor in 58 of 85 (68.2%), equivocal findings in 12 of 85 (14.1%), and definite residual tumor in 15 of 85 (17.6%) patients. Six of 85 (7.1%) demonstrated tumor regrowth by 3 years, and 2 further patients demonstrated true tumor recurrence at 3 and 6 years after surgery, respectively, for a total recurrence rate of 9.4% (8 of 85). Eight of the 93 patients were irradiated between 3 months and 4 years after pituitary surgery. In 3 patients with tumor regrowth, 2 exhibited residual tumor and 1 had no residual findings at the 3-month postoperative imaging. Overall, Ki-67 labeling index or Knosp grading did not predict recurrence.ConclusionTumor recurrence at 3 years was low (1 of 58; 1.7%) if the 3-month postoperative MRI showed no residual tumor. The findings support a less frequent imaging schedule for this group. Patients with definite residual tumor visible at 3 months harbor the greatest risk for tumor growth, but regrowth does not occur in all patients (6 of 15; 40%)

Sympathetic Nerve Fibers in Human Cervical and Thoracic Vagus Nerves

Background Vagus nerve stimulation therapy (VNS) has been used for chronic heart failure (CHF), and is believed to improve imbalance of autonomic control by increasing parasympathetic activity. Although it is known that there is neural communication between the VN and the cervical sympathetic trunk, there are few data regarding the quantity and/or distribution of the sympathetic components within the VN. Objective To examine the sympathetic component within human VN and correlate these with the presence of cardiac and neurologic diseases. Methods We performed immunohistochemistry on 31 human cervical and thoracic VNs (total 104 VNs) from autopsies and we reviewed the patients’ records. We correlated the quantity of sympathetic nerve fibers within the VNs with cardiovascular and neurologic disease states. Results All 104 VNs contain TH positive (sympathetic) nerve fibers; the mean TH positive areas were 5.47% in right cervical, 3.97% in left cervical, 5.11% in right thoracic, and 4.20% in left thoracic VN. The distribution of TH positive nerve fibers varied from case to case: central, peripheral, or scattered throughout nerve bundles. No statistically significant differences in nerve morphology were seen between diseases in which VNS is considered effective (depression and CHF), and other cardiovascular diseases, or neurodegenerative disease. Conclusion Human VNs contain sympathetic nerve fibers. The sympathetic component within the VN could play a role in physiologic effects reported with VNS. The recognition of sympathetic nerve fibers in the VNs may lead to better understanding of the therapeutic mechanisms of VNS

Enhanced Delivery of Rituximab Into Brain and Lymph Nodes Using Timed-Release Nanocapsules in Non-Human Primates.

Tumor metastasis into the central nervous system (CNS) and lymph nodes (LNs) is a major obstacle for effective therapies. Therapeutic monoclonal antibodies (mAb) have revolutionized tumor treatment; however, their efficacy for treating metastatic tumors-particularly, CNS and LN metastases-is poor due to inefficient penetration into the CNS and LNs following intravenous injection. We recently reported an effective delivery of mAb to the CNS by encapsulating the anti-CD20 mAb rituximab (RTX) within a thin shell of polymer that contains the analogs of choline and acetylcholine receptors. This encapsulated RTX, denoted as n-RTX, eliminated lymphoma cells systemically in a xenografted humanized mouse model using an immunodeficient mouse as a recipient of human hematopoietic stem/progenitor cells and fetal thymus more effectively than native RTX; importantly, n-RTX showed notable anti-tumor effect on CNS metastases which is unable to show by native RTX. As an important step toward future clinical translation of this technology, we further analyzed the properties of n-RTX in immunocompetent animals, rats, and non-human primates (NHPs). Our results show that a single intravenous injection of n-RTX resulted in 10-fold greater levels in the CNS and 2-3-fold greater levels in the LNs of RTX, respectively, than the injection of native RTX in both rats and NHPs. In addition, we demonstrate the enhanced delivery and efficient B-cell depletion in lymphoid organs of NHPs with n-RTX. Moreover, detailed hematological analysis and liver enzyme activity tests indicate n-RTX treatment is safe in NHPs. As this nanocapsule platform can be universally applied to other therapeutic mAbs, it holds great promise for extending mAb therapy to poorly accessible body compartments

Sustained delivery and molecular targeting of a therapeutic monoclonal antibody to metastases in the central nervous system of mice.

Approximately 15-40% of all cancers develop metastases in the central nervous system (CNS), yet few therapeutic options exist to treat them. Cancer therapies based on monoclonal antibodies are widely successful, yet have limited efficacy against CNS metastases, owing to the low levels of the drug reaching the tumour site. Here, we show that the encapsulation of rituximab within a crosslinked zwitterionic polymer layer leads to the sustained release of rituximab as the crosslinkers are gradually hydrolysed, enhancing the CNS levels of the antibody by approximately tenfold with respect to the administration of naked rituximab. When the nanocapsules were functionalized with CXCL13-the ligand for the chemokine receptor CXCR5, which is frequently found on B-cell lymphoma-a single dose led to improved control of CXCR5-expressing metastases in a murine xenograft model of non-Hodgkin lymphoma, and eliminated lymphoma in a xenografted humanized bone marrow-liver-thymus mouse model. Encapsulation and molecular targeting of therapeutic antibodies could become an option for the treatment of cancers with CNS metastases

Loss of O-GlcNAc glycosylation in forebrain excitatory neurons induces neurodegeneration

O-GlcNAc glycosylation (or O-GlcNAcylation) is a dynamic, inducible posttranslational modification found on proteins associated with neurodegenerative diseases such as α-synuclein, amyloid precursor protein, and tau. Deletion of the O-GlcNAc transferase (ogt) gene responsible for the modification causes early postnatal lethality in mice, complicating efforts to study O-GlcNAcylation in mature neurons and to understand its roles in disease. Here, we report that forebrain-specific loss of OGT in adult mice leads to progressive neurodegeneration, including widespread neuronal cell death, neuroinflammation, increased production of hyperphosphorylated tau and amyloidogenic Aβ-peptides, and memory deficits. Furthermore, we show that human cortical brain tissue from Alzheimer’s disease patients has significantly reduced levels of OGT protein expression compared with cortical tissue from control individuals. Together, these studies indicate that O-GlcNAcylation regulates pathways critical for the maintenance of neuronal health and suggest that dysfunctional O-GlcNAc signaling may be an important contributor to neurodegenerative diseases