Elucidation of the Mechanisms By Which Anesthetics Induce Blood-Brain Barrier Breakdown and Delirium in the Elderly

Delirium is a highly prevalent neuropsychiatric or neurocognitive disorder that presents a major problem to modern healthcare. Patients suffering from delirium normally have a worse prognosis, prolonged hospital stay, increased hospital cost, long-term cognitive impairment, and higher mortality rates. Many factors can predispose one to develop delirium, which makes treating this disorder a daunting task. Unfortunately, delirium is the most common psychiatric syndrome found in the hospital setting. In fact, a form of delirium known as postoperative delirium (POD) is one of the most common postoperative complications faced by elderly patients undergoing surgery. POD is a major problem in modern healthcare, and it will only become worse because the world’s older population (65+) is projected to triple between 2009 and 2050. This realization caused POD to emerge as an area of research interest. Many precipitating factors can cause one to develop POD, including exposure to anesthetics. Studies have indicated that many patients who were given general anesthesia have developed delirium; however, no studies have explained the mechanism by which anesthesia induces POD in patients. Unraveling this mechanism is the main goal of the research being presented here. Our lab has hypothesized that POD is caused by a temporary, anesthesia- or drug-induced breakdown of the blood-brain barrier (BBB). The BBB, which is formed by the vascular endothelium in the brain, is a highly selective barrier that separates the circulating blood from the brain and prevents a large number of substances from entering the brain. We believe that BBB breakdown after exposure to anesthetics allows an influx of plasma components into the brain tissue that disrupts brain homeostasis and causes neuronal misfiring. In the short-term, this culminates into the array of symptoms that hallmark POD. In the long-term, if not reversed or only partially reversed, this could trigger subsequent Postoperative Cognitive Decline (POCD) and Dementia. A preliminary anesthesia study conducted in our lab revealed that exposure to the inhalation anesthetics (IAs) Sevoflurane and Isoflurane causes immediate structural changes in brain vascular endothelial cells (BVECs), including an overall flattening of surface membranes and loss of the tight junction ridge. These structural changes can lead to the formation of holes in the vascular endothelial lining. This study also revealed that exposure to Sevoflurane leads to an increase in BBB permeability. A subsequent study revealed that Sevoflurane increases BBB permeability in preadolescent and elderly rats, age-dependent changes occur in the luminal surface topography of brain vascular endothelial cells associated with development and maintenance of the BBB, and Sevoflurane and Isoflurane induce changes in BVEC luminal surface topography that may be linked to increased BBB permeability. In vitro experiments using a human brain endothelial cell line (hCMEC/D3) that can form a BBB-like barrier yielded the following results: (1) hCMEC/D3 cells express tight junction proteins, (2) transendothelial electrical resistance (TEER) decreases and barrier permeability increases after hCMEC/D3 cells are exposed to anesthesia, (3) the distribution and expression of the tight junction protein ZO-1 in hCMEC/D3 cells is not affected by exposure to anesthesia, (4) addition of DMSO or floating cells to the cell culture medium does not aid the transfer of anesthetics from the air to the cell monolayer, and (5) Histamine and Acetaminophen induce contraction in hCMEC/D3 cells, which can compromise barrier functional integrity. Finally, studies on the effects of the specialized pro-resolving lipid mediator (SPM) Lipoxin in resolving BBB insults revealed the following: (1) bacterial lipopolysaccharide (LPS) injections led to an increase in BBB permeability, as evidenced by detecting IgG, a serum component normally restricted to blood vessels, in rat brain tissue. (2) Lipoxin reduces LPS-induced BBB permeability, as evidenced by decreased levels of IgG in rat brain tissue. (3) LPS induces a number of luminal surface changes in rat BVECs, as shown by scanning electron microscopy. (4) Lipoxin helps restore key luminal surface features of rat BVECs to near normal, and most importantly, blocks the death of BVECs and the associated loss of barrier integrity

Autoantibodies as Diagnostic Biomarkers for the Detection and Subtyping of Multiple Sclerosis

The goal of this preliminary proof-of-concept study was to use human protein microarrays to identify blood-based autoantibody biomarkers capable of diagnosing multiple sclerosis (MS). Using sera from 112 subjects, including 51 MS subjects, autoantibody biomarkers effectively differentiated MS subjects from age- and gender-matched normal and breast cancer controls with 95.0% and 100% overall accuracy, but not from subjects with Parkinson\u27s disease. Autoantibody biomarkers were also useful in distinguishing subjects with the relapsing-remitting form of MS from those with the secondary progressive subtype. These results demonstrate that autoantibodies can be used as noninvasive blood-based biomarkers for the detection and subtyping of M

Detection of Alzheimer\u27s disease at mild cognitive impairment and disease progression using autoantibodies as blood-based biomarkers

Introduction There is an urgent need to identify biomarkers that can accurately detect and diagnose Alzheimer\u27s disease (AD). Autoantibodies are abundant and ubiquitous in human sera and have been previously demonstrated as disease-specific biomarkers capable of accurately diagnosing mild-moderate stages of AD and Parkinson\u27s disease. Methods Sera from 236 subjects, including 50 mild cognitive impairment (MCI) subjects with confirmed low CSF Aβ42 levels, were screened with human protein microarrays to identify potential biomarkers for MCI. Autoantibody biomarker performance was evaluated using Random Forest and Receiver Operating Characteristic curves. Results Autoantibody biomarkers can differentiate MCI patients from age-matched and gender-matched controls with an overall accuracy, sensitivity, and specificity of 100.0%. They were also capable of differentiating MCI patients from those with mild-moderate AD and other neurologic and non-neurologic controls with high accuracy. Discussion Autoantibodies can be used as noninvasive and effective blood-based biomarkers for early diagnosis and staging of AD

Potential utility of autoantibodies as blood-based biomarkers for early detection and diagnosis of Parkinson’s disease

Introduction There is a great need to identify readily accessible, blood-based biomarkers for Parkinson’s disease (PD) that are useful for accurate early detection and diagnosis. This advancement would allow early patient treatment and enrollment into clinical trials, both of which would greatly facilitate the development of new therapies for PD. Methods Sera from a total of 398 subjects, including 103 early-stage PD subjects derived from the Deprenyl and Tocopherol Antioxidative Therapy of Parkinsonism (DATATOP) study, were screened with human protein microarrays containing 9,486 potential antigen targets to identify autoantibodies potentially useful as biomarkers for PD. A panel of selected autoantibodies with a higher prevalence in early-stage PD was identified and tested using Random Forest for its ability to distinguish early-stage PD subjects from controls and from individuals with other neurodegenerative and non-neurodegenerative diseases. Results Results demonstrate that a panel of selected, blood-borne autoantibody biomarkers can distinguish early-stage PD subjects (90% confidence in diagnosis) from age- and sex-matched controls with an overall accuracy of 87.9%, a sensitivity of 94.1% and specificity of 85.5%. These biomarkers were also capable of differentiating patients with early-stage PD from those with more advanced (mild-moderate) PD with an overall accuracy of 97.5%, and could distinguish subjects with early-stage PD from those with other neurological (e.g., Alzheimer’s disease and multiple sclerosis) and non-neurological (e.g., breast cancer) diseases. Conclusion These results demonstrate, for the first time, that a panel of selected autoantibodies may prove to be useful as effective blood-based biomarkers for the diagnosis of early-stage PD

Evidence That Brain-Reactive Autoantibodies Contribute to Chronic Neuronal Internalization of Exogenous Amyloid-β1-42 and Key Cell Surface Proteins During Alzheimer\u27s Disease Pathogenesis

Blood-brain barrier (BBB) permeability is a recognized early feature of Alzheimer\u27s disease (AD). In the present study, we examined consequences of increased BBB permeability on the development of AD-related pathology by tracking selected leaked plasma components and their interactions with neurons in vivo and in vitro. Histological sections of cortical regions of postmortem AD brains were immunostained to determine the distribution of amyloid-β1-42 (Aβ42), cathepsin D, IgG, GluR2/3, and alpha7 nicotinic acetylcholine receptor (α7nAChR). Results revealed that chronic IgG binding to pyramidal neurons coincided with internalization of Aβ42, IgG, GluR2/3, and α7nAChR as well as lysosomal compartment expansion in these cells in regions of AD pathology. To test possible mechanistic interrelationships of these phenomena, we exposed differentiated SH-SY5Y neuroblastoma cells to exogenous, soluble Aβ42 peptide and serum from AD and control subjects. The rate and extent of Aβ42 internalization in these cells was enhanced by serum containing neuron-binding IgG autoantibodies. This was confirmed by treating cells with individual antibodies specific for α7nAChR, purified IgG from AD or non-AD sera, and sera devoid of IgG, in the presence of 100 nM Aβ42. Initial co-localization of IgG, α7nAChR, and Aβ42 was temporally and spatially linked to early endosomes (Rab11) and later to lysosomes (LAMP-1). Aβ42 internalization was attenuated by treatment with monovalent F(ab) antibody fragments generated from purified IgG from AD serum and then rescued by coupling F(ab) fragments with divalent human anti-Fab. Overall, results suggest that cross-linking of neuron-binding autoantibodies targeting cell surface proteins can accelerate intraneuronal Aβ42 deposition in AD

Unearthing Patterns in Venetian History: Developing an Online Tool for Discovering Patterns in Subterranean Archaeological Sites

Archaeologists in Venice would benefit from digital tools to improve their efficiency in data collection, visualization, and correlation. To aid in archaeological research, we developed a three-part prototype system, consisting of a web app, online database, and a map-based website, for the archaeological firm Studio Zandinella. The first aspect of the project was an online database that allows archaeologists to store and visualize archaeological data. The second part of the system was a data collecting system that records information on the database. The third part of the system was a map-based website that visualizes the contents of the database. These tools will allow Venetian archaeologists to better conduct research and find patterns of data across archaeological sites in Venice

Autonomous Lionfish Harvester

The Lionfish Major Qualifying Project Team has developed a harvesting mechanism for the purpose of hunting lionfish, with the intent of attaching it to an autonomous submarine robot. The harvester functions as an independent mechanism capable of sensing lionfish, determining their location, and harvesting them

Harnessing neurovascular interaction to guide axon growth

Abstract Regulating the intrinsic interactions between blood vessels and nerve cells has the potential to enhance repair and regeneration of the central nervous system. Here, we evaluate the efficacy of aligned microvessels to induce and control directional axon growth from neural progenitor cells in vitro and host axons in a rat spinal cord injury model. Interstitial fluid flow aligned microvessels generated from co-cultures of cerebral-derived endothelial cells and pericytes in a three-dimensional scaffold. The endothelial barrier function was evaluated by immunostaining for tight junction proteins and quantifying the permeability coefficient (~10−7 cm/s). Addition of neural progenitor cells to the co-culture resulted in the extension of Tuj-positive axons in the direction of the microvessels. To validate these findings in vivo, scaffolds were transplanted into an acute spinal cord hemisection injury with microvessels aligned with the rostral-caudal direction. At three weeks post-surgery, sagittal sections indicated close alignment between the host axons and the transplanted microvessels. Overall, this work demonstrates the efficacy of exploiting neurovascular interaction to direct axon growth in the injured spinal cord and the potential to use this strategy to facilitate central nervous system regeneration

Sevoflurane and Isoflurane induce structural changes in brain vascular endothelial cells and increase Blood-brain barrier permeability: Possible link to postoperative delirium and cognitive decline

A large percentage of patients subjected to general anesthesia at 65 years and older exhibit postoperative delirium (POD). Here, we test the hypothesis that inhaled anesthetics (IAs), such as Sevoflurane and Isoflurane, act directly on brain vascular endothelial cells (BVECs) to increase blood-brain barrier (BBB) permeability, thereby contributing to POD. Rats of young (3–5 months), middle (10–12 months) and old (17–19 months) ages were anesthetized with Sevoflurane or Isoflurane for 3 h. After exposure, some were euthanized immediately; others were allowed to recover for 24 h before sacrifice. Immunohistochemistry was employed to monitor the extent of BBB breach, and scanning electron microscopy (SEM) was used to examine changes in the luminal surfaces of BVECs. Quantitative immunohistochemistry revealed increased BBB permeability in older animals treated with Sevoflurane, but not Isoflurane. Extravasated immunoglobulin G showed selective affinity for pyramidal neurons. SEM demonstrated marked flattening of the luminal surfaces of BVECs in anesthetic-treated rats. Results suggest an aging-linked BBB compromise resulting from exposure to Sevoflurane. Changes in the luminal surface topology of BVECs indicate a direct effect on the plasma membrane, which may weaken or disrupt their BBB-associated tight junctions. Disruption of brain homeostasis due to plasma influx into the brain parenchyma and binding of plasma components (e.g., immunoglobulins) to neurons may contribute to POD. We propose that, in the elderly, exposure to some IAs can cause BBB compromise that disrupts brain homeostasis, perturbs neuronal function and thereby contributes to POD. If unresolved, this may progress to postoperative cognitive decline and later dementia