Diana G. Hernandez-Ontiveros

MICROGLIA ACTIVATION AS A BIOMARKER FOR TRAUMATIC BRAIN INJURY

Traumatic brain injury (TBI) has become the signature wound of wars in Afghanistan and Iraq. Injury may result from a mechanical force, a rapid acceleration-deceleration movement, or a blast wave. A cascade of secondary cell death events ensues after the initial injury. In particular, multiple inflammatory responses accompany TBI. A series of inflammatory cytokines and chemokines spreads to normal brain areas juxtaposed to the core impacted tissue. Among the repertoire of immune cells involved, microglia is a key player in propagating inflammation to tissues neighboring the core site of injury. Neuroprotective drug trials in TBI have failed, likely due to their sole focus on abrogating neuronal cell death and ignoring the microglia response despite these inflammatory cells’ detrimental effects on the brain. Another relevant point to consider is the veracity of results of animal experiments due to deficiencies in experimental design, such as incomplete or inadequate method description, data misinterpretation, and reporting may introduce bias and give false-positive results. Thus, scientific publications should follow strict guidelines that include randomization, blinding, sample-size estimation, and accurate handling of all data (Landis et al., 2012). A prolonged state of inflammation after brain injury may linger for years and predispose patients to develop other neurological disorders, such as Alzheimer’s disease. TBI patients display progressive and long-lasting impairments in their physical, cognitive, behavioral, and social performance. Here, we discuss inflammatory mechanisms that accompany TBI in an effort to increase our understanding of the dynamic pathological condition as the disease evolves over time and begin to translate these findings for defining new and existing inflammation-based biomarkers and treatments for TBI.

Intravenous Transplants of Human Adipose-Derived Stem Cell Protect the Brain from Traumatic Brain Injury-Induced Neurodegeneration and Motor and Cognitive Impairments: Cell Graft Biodistribution and Soluble Factors in Young and Aged Rats

Traumatic brain injury (TBI) survivors exhibit motor and cognitive symptoms from the primary injury that can become aggravated over time because of secondary cell death. In the present in vivo study, we examined the beneficial effects of human adipose-derived stem cells (hADSCs) in a controlled cortical impact model of mild TBI using young (6 months) and aged (20 months) F344 rats. Animals were transplanted intravenously with 4 × 106 hADSCs (Tx), conditioned media (CM), or vehicle (unconditioned media) at 3 h after TBI. Significant amelioration of motor and cognitive functions was revealed in young, but not aged, Tx and CM groups. Fluorescent imaging in vivo and ex vivo revealed 1,1′ dioactadecyl-3-3-3′,3′-tetramethylindotricarbocyanine iodide-labeled hADSCs in peripheral organs and brain after TBI. Spatiotemporal deposition of hADSCs differed between young and aged rats, most notably reduced migration to the aged spleen. Significant reduction in cortical damage and hippocampal cell loss was observed in both Tx and CM groups in young rats, whereas less neuroprotection was detected in the aged rats and mainly in the Tx group but not the CM group. CM harvested from hADSCs with silencing of either NEAT1 (nuclear enriched abundant transcript 1) or MALAT1 (metastasis associated lung adenocarcinoma transcript 1), long noncoding RNAs (lncRNAs) known to play a role in gene expression, lost the efficacy in our model. Altogether, hADSCs are promising therapeutic cells for TBI, and lncRNAs in the secretome is an important mechanism of cell therapy. Furthermore, hADSCs showed reduced efficacy in aged rats, which may in part result from decreased homing of the cells to the spleen.

Amyotrophic lateral sclerosis: a neurovascular disease.

Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disease with a complicated pathogenesis. Compelling evidence indicates impairment of all neurovascular unit components including the blood-brain and blood-spinal cord barriers (BBB/BSCB) in both patients and animal models, leading to classification of ALS as a neurovascular disease. The present review provides an updated analysis of the normal and impaired BBB/BSCB, focusing on the ALS-altered barrier. Here we describe the roles of cellular components, tight junctions, transport systems, cell interactions, cytokines, matrix metalloproteinases, and free radicals in the BBB/BSCB disruption, along with recent evidence from experimental and clinical ALS studies. The BBB/BSCB is a promising research area in ALS and this review will reveal some aspects of microvascular pathology in ALS and hopefully provide ideas for the development of new therapeutic strategies.

Impaired blood–brain/spinal cord barrier in ALS patients

Vascular pathology, including blood-brain/spinal cord barrier (BBB/BSCB) alterations, has recently been recognized as a key factor possibly aggravating motor neuron damage, identifying a neurovascular disease signature for ALS. However, BBB/BSCB competence in sporadic ALS (SALS) is still undetermined. In this study, BBB/BSCB integrity in postmortem gray and white matter of medulla and spinal cord tissue from SALS patients and controls was investigated. Major findings include (1) endothelial cell damage and pericyte degeneration, (2) severe intra- and extracellular edema, (3) reduced CD31 and CD105 expressions in endothelium, (4) significant accumulation of perivascular collagen IV, and fibrin deposits (5) significantly increased microvascular density in lumbar spinal cord, (6) IgG microvascular leakage, (7) reduced tight junction and adhesion protein expressions. Microvascular barrier abnormalities determined in gray and white matter of the medulla, cervical, and lumbar spinal cord of SALS patients are novel findings. Pervasive barrier damage discovered in ALS may have implications for disease pathogenesis and progression, as well as for uncovering novel therapeutic targets.

Blood-Brain Barrier Alterations Provide Evidence of Subacute Diaschisis in an Ischemic Stroke Rat Model

Background Comprehensive stroke studies reveal diaschisis, a loss of function due to pathological deficits in brain areas remote from initial ischemic lesion. However, blood-brain barrier (BBB) competence in subacute diaschisis is uncertain. The present study investigated subacute diaschisis in a focal ischemic stroke rat model. Specific focuses were BBB integrity and related pathogenic processes in contralateral brain areas. Methodology/Principal Findings In ipsilateral hemisphere 7 days after transient middle cerebral artery occlusion (tMCAO), significant BBB alterations characterized by large Evans Blue (EB) parenchymal extravasation, autophagosome accumulation, increased reactive astrocytes and activated microglia, demyelinization, and neuronal damage were detected in the striatum, motor and somatosensory cortices. Vascular damage identified by ultrastuctural and immunohistochemical analyses also occurred in the contralateral hemisphere. In contralateral striatum and motor cortex, major ultrastructural BBB changes included: swollen and vacuolated endothelial cells containing numerous autophagosomes, pericyte degeneration, and perivascular edema. Additionally, prominent EB extravasation, increased endothelial autophagosome formation, rampant astrogliosis, activated microglia, widespread neuronal pyknosis and decreased myelin were observed in contralateral striatum, and motor and somatosensory cortices. Conclusions/Significance These results demonstrate focal ischemic stroke-induced pathological disturbances in ipsilateral, as well as in contralateral brain areas, which were shown to be closely associated with BBB breakdown in remote brain microvessels and endothelial autophagosome accumulation. This microvascular damage in subacute phase likely revealed ischemic diaschisis and should be considered in development of treatment strategies for stroke.

Compromised blood–brain barrier competence in remote brain areas in ischemic stroke rats at the chronic stage

Stroke is a life‐threatening disease leading to long‐term disability in stroke survivors. Cerebral functional insufficiency in chronic stroke might be due to pathological changes in brain areas remote from the initial ischemic lesion, i.e., diaschisis. Previously, we showed that the damaged blood–brain barrier (BBB) was involved in subacute diaschisis. The present study investigated BBB competence in chronic diaschisis by using a transient middle cerebral artery occlusion (tMCAO) rat model. Our results demonstrated significant BBB damage mostly in the ipsilateral striatum and motor cortex in rats at 30 days after tMCAO. The BBB alterations were also determined in the contralateral hemisphere via ultrastructural and immunohistochemical analyses. Major BBB pathological changes in contralateral remote striatum and motor cortex areas included 1) vacuolated endothelial cells containing large autophagosomes, 2) degenerated pericytes displaying mitochondria with cristae disruption, 3) degenerated astrocytes and perivascular edema, 4) Evans blue extravasation, and 5) appearance of parenchymal astrogliosis. Discrete analyses of striatal and motor cortex areas revealed significantly higher autophagosome accumulation in capillaries of ventral striatum and astrogliosis in dorsal striatum in both cerebral hemispheres. These widespread microvascular alterations in ipsilateral and contralateral brain hemispheres suggest persistent and/or continued BBB damage in chronic ischemia. The pathological changes in remote brain areas likely indicate chronic ischemic diaschisis, which should be considered in the development of treatment strategies for stroke. J. Comp. Neurol. 522:3120–3137, 2014.

Neurovascular aspects of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disease with a complicated and poorly understood pathogenesis. Strong evidence indicates impairment of all neurovascular unit components including the blood-brain and blood-spinal cord barriers (BBB/BSCB) in both patients and animal models. The present review provides an updated analysis of the microvascular pathology and impaired BBB/BSCB in ALS. Based on experimental and clinical ALS studies, the roles of cellular components, cell interactions, tight junctions, transport systems, cytokines, matrix metalloproteinases, and free radicals in the BBB/BSCB disruption are discussed. The impact of BBB/BSCB damage in ALS pathogenesis is a novel research topic, and this review will reveal some aspects of microvascular pathology involved in the disease and hopefully engender new therapeutic approaches.

Reduction of Circulating Endothelial Cells in Peripheral Blood of ALS Patients

Background Amyotrophic Lateral Sclerosis (ALS) treatment is complicated by the various mechanisms underlying motor neuron degeneration. Recent studies showed that the blood-brain barrier (BBB) and blood-spinal cord barrier (BSCB) are compromised in an animal model of ALS due to endothelial cell degeneration. A later study demonstrated a loss of endothelium integrity in the spinal cords of ALS patients. Since circulating endothelial cells (CECs) in the peripheral blood are associated with endothelium damage, being detached dysfunctional endothelial cells, we hypothesized that CEC levels may reflect endothelium condition in ALS patients. Methodology/Principal Findings CEC levels were estimated in whole blood smears from ALS patients with moderate stage (MALS), severe stage (SALS), and healthy controls by CD146 expression using immunocytochemistry. A significant reduction of CECs was detected in MALS and SALS patients. Conclusions/Significance CECs did not predict endothelium state in ALS patients; however, endothelial damage and/or impaired endothelium repair may occur in ALS leading to BBB/BSCB dysfunction. Reduced CECs in peripheral blood of ALS patients may indicate different mechanisms of endothelial damage and repair, rather than only detachment of dysfunctional endothelial cells. Although a potential mechanism of CEC reduction is discussed, establishing a reliable indicator of endothelial dysfunction/damage is important for evaluation of BBB/BSCB status in ALS patients during disease progression.

Resveratrol and Omega-3 Fatty Acid: Its Implications in Cardiovascular Diseases

The present review aims at summarizing the major therapeutic roles of resveratrol and omega-3 fatty acids (O3FAs) along with their related pathways. This article reviews some of the key studies involving the health benefits of resveratrol and O3FAs. Oxidative stress has been considered as one of the most important pathophysiological factors associated with various cardiovascular disease conditions. Resveratrol, with the potent antioxidant and free radical scavenging properties, has been proven to be a significantly protective compound in restoring the normal cardiac health. A plethora of research also demonstrated the reduction of the risk of coronary heart disease, hypertension, and stroke, and their complications by O3FAs derived from fish and fish oils. This review describes the potential cardioprotective role of resveratrol and O3FAs in ameliorating the endoplasmic reticulum stress.

Blood-brain barrier impairment in MPS III patients

BackgroundMucopolysaccharidosis type III (MPS III) is an autosomal recessive disorder caused by deficiency of a specific enzyme leading to heparan sulfate (HS) accumulation within cells and to eventual progressive cerebral and systemic organ abnormalities. Different enzyme deficiencies comprise the MPS III subcategories (A, B, C, D). Since neuropathological manifestations are common to all MPS III types, determining blood-brain barrier (BBB) condition may be critical to understand potential additional disease mechanisms.MethodsWe investigated BBB integrity in various brain structures of post-mortem tissues from an eleven year old Caucasian female with MPS III A and from a twenty four year old Caucasian female with MPS III D. Control tissues were obtained post-mortem from three Caucasians without neurological deficits: a twelve year old male, a twenty four year old female, and a twenty seven year old female. BBB capillary ultrastructure (electron microscopy) and capillary functional integrity (IgG leakage, tight junction proteins, and lysosomal accumulation within endothelium) were examined.ResultsCompromised BBB integrity was found in both MPS III cases. Major study findings were: (1) capillary endothelial and pericyte cell damage; (2) mucopolysaccharide bodies in a majority of endothelial cells and pericytes rupturing cell membranes; (3) severe extracellular edema; (4) IgG microvascular leakage and reductions of occludin and claudin-5 with variations between MPS III types; (5) extensive lysosomal accumulation in capillary endothelium.ConclusionsThese new findings of BBB structural and functional impairment, although from only two cases, MPS III A and III D, may have implications for disease pathogenesis and should be considered in treatment development for MPS III.