Background: Thromboembolism is a major cause of events in carotid artery (CA) disease and predisp... more Background: Thromboembolism is a major cause of events in carotid artery (CA) disease and predisposes the dissemination of clots to upstream ischemic strokes. Although diagnostic methods are available to define thromboembolic strokes (CT, MRI, etc.), there is no technology to provide ambulatory assessment to ‘content image’ thrombi within the CA bifurcation free of the hospital setting. To address this unmet medical need we bioengineered the joining of the disintegrin bitistatin (Bit) to fluorescent NanoDiamond Particles (F-NDP) in order to bind to and non-invasively image vascular clots. F-NDP-Bit preferentially binds to the human platelet fibrinogen receptor (GPIIB/IIIA). F-NDP-Bit was systematically evaluated for NIR emission capacity in various tissues and demonstrated penetration of NIR fluorescence across distances similar to the distance from the human skin surface to the CA bifurcation. Methods: In vitro studies were conducted to evaluate binding of F-NDP-Bit to purified human GPIIB/IIIA. Also, the ability of the F-NDP-Bit to bind to vascular clots In Vivo was investigated in rat FeCl3-induced internal CA coagulation. Results: Using the specific GPIIB/IIIA antagonist lotrafiban, In Vitro specific and concentration-related F-NDP-Bit binding was demonstrated. In Vivo , intravenous administration of F-NDP-Bit during the evolution of FeCl3-induced internal CA thrombosis resulted in the dose-related clot accumulation of F-NDP-Bit that was cross-validated by three independent methods (all measures were significant as described; p < 0.05): ( 1 ) In Situ whole rat imaging via In Vivo Imaging System (IVIS: using Ex 54 nm; Em 695-770 nm); ( 2 ) Ex Vivo whole vessel/clot imaging (Scanning Confocal Microscopy), and ( 3 ) Extract, isolate and quantitate F-NDP-Bit following internal CA clot dissolution (12N HNO3) and direct counting (hemocytometer). Conclusions: These data indicate that F-NDP-Bit might address the need for fast, safe and highly affordable ambulatory imaging of vascular clot burden. Functionalization of F-NDP with selective ligands that can be pathognomonic for many disease situations also could facilitate risk assessment, earlier intervention and preventative medicine.
Journal of Cerebral Blood Flow and Metabolism, Nov 1, 1998
Brief occlusion of the middle cerebral artery (i.e., ischemic preconditioning; PC) induces signif... more Brief occlusion of the middle cerebral artery (i.e., ischemic preconditioning; PC) induces significant brain protec tion to subsequent severe ischemic events. In an effort to dis cover genes responsible for ischemic tolerance, we have ap plied a new technique, suppression subtractive hybridization (SSH), to identify genes that are upregulated by Pc. Using this SSH approach, a cDNA that encodes tissue inhibitor of matrix metalloproteinase-l (TIMP-l) was identified. Time course studies using Northern analysis revealed that TIMP-l mRNA was significantly elevated at 24 hours (3.3-fold over controls, P
Background: Mice expressing mutated hAPP in the entorhinal cortex (EC) display, hypersynchrony of... more Background: Mice expressing mutated hAPP in the entorhinal cortex (EC) display, hypersynchrony of the EC-hippocampus circuit, caused by decreased inhibitory tone (Angulo et al., NBD 2017). A similar EC inhibitory failure was also observed in mice expressing hAPOE4, (Nuriel et al., Nat Neursc 2017). Here we evaluated changes in EC
After an acute ischemia/reperfusion of the rat retina, the activation of cytotoxic proteases, inc... more After an acute ischemia/reperfusion of the rat retina, the activation of cytotoxic proteases, including calpain, results in necrosis and apoptosis of retinal ganglion cells resulting in their degeneration. Using a systemically administered calpain inhibitor that crosses the blood-retinal barrier would provide for novel systemic intervention that protects the retina from acute injury and loss of function. Herein, we study a novel calpain peptide inhibitor, cysteic-leucyl-argininal (CYLA), in an in-vivo rat model of retinal ischemia to determine functional protection using electroretinography. The CYLA prodrug was administered intraperitoneally before and/or after ischemia-reperfusion at concentrations of 20-40 mg/kg. We found that administering 20 mg/kg of CYLA only after ischemia provides significant preservation of retinal function.
We describe here the cloning and characterization of a rat homolog of the chemokine receptor CXCR... more We describe here the cloning and characterization of a rat homolog of the chemokine receptor CXCR3. The predicted amino acid sequence of rat CXCR3 contains 367 amino acid residues, sharing 96 and 87% amino acid sequence identity to the murine and human CXCR3, respectively. Among a large panel of chemokines tested, only interferon-inducible protein-10 (IP-10), interferon-gamma-induced monokine, and interferon-inducible T cell alpha-chemoattractant demonstrated specific abilities to induce an intracellular calcium mobilization response in human embryonic kidney 293 cells transfected with rat CXCR3 expression vector. (125)I-IP-10 competition binding studies to the CXCR3-transfected human embryonic kidney 293 cells demonstrated that human IP-10 and interferon-inducible T cell alpha-chemoattractant are more potent ligands than human interferon-gamma-induced monokine. Following our previous observation for the induced expression of IP-10 in focal stroke, we demonstrate here the time-dependent up-regulation of CXCR3 mRNA in the rat ischemic cortex after permanent occlusion of the middle cerebral artery. A significant increase in (125)I-IP-10-specific binding to ischemic cerebral cortical samples was obtained and paralleled the increase in CXCR3 mRNA expression. The changes in receptor expression and ligand binding correlate highly with known changes in leukocyte accumulation, and gliosis occurred after focal stroke. These data suggest that CXCR3/IP-10 may be a potential novel therapeutic target in focal stroke. In addition, the cloning of rat CXCR3 provides an important tool for the investigation of the pathophysiological role of CXCR3 in other rodent disease models.
Small vessel cerebrovascular disease, visualized as white matter hyperintensities on T2-weighted ... more Small vessel cerebrovascular disease, visualized as white matter hyperintensities on T2-weighted magnetic resonance imaging, contributes to the clinical presentation of Alzheimer's disease. However, the extent to which cerebrovascular disease represents an independent pathognomonic feature of Alzheimer's disease or directly promotes Alzheimer's pathology is unclear. The purpose of this study was to examine the association between white matter hyperintensities and plasma levels of tau and to determine if white matter hyperintensities and tau levels interact to predict Alzheimer's disease diagnosis. To confirm that cerebrovascular disease promotes tau pathology, we examined tau fluid biomarker concentrations and pathology in a mouse model of ischaemic injury. Three hundred ninety-one participants from the Alzheimer's Disease Neuroimaging Initiative (74.5 6 7.1 years of age) were included in this cross-sectional analysis. Participants had measurements of plasma total-tau, cerebrospinal fluid beta-amyloid, and white matter hyperintensities, and were diagnosed clinically as Alzheimer's disease (n ¼ 97), mild cognitive impairment (n ¼ 186) or cognitively normal control (n ¼ 108). We tested the relationship between plasma tau concentration and white matter hyperintensity volume across diagnostic groups. We also examined the extent to which white matter hyperintensity volume, plasma tau, amyloid positivity status and the interaction between white matter hyperintensities and plasma tau correctly classifies diagnostic category. Increased white matter hyperintensity volume was associated with higher plasma tau concentration, particularly among those diagnosed clinically with Alzheimer's disease. Presence of brain amyloid and the interaction between plasma tau and white matter hyperintensity volume distinguished Alzheimer's disease and mild cognitive impairment participants from controls with 77.6% and 63.3% accuracy, respectively. In 63 Alzheimer's Disease Neuroimaging Initiative participants who came to autopsy (82.33 6 7.18 age at death), we found that higher degrees of arteriosclerosis were associated with higher Braak staging, indicating a positive relationship between cerebrovascular disease and neurofibrillary pathology. In a transient middle cerebral artery occlusion mouse model, aged mice that received transient middle cerebral artery occlusion, but not sham surgery, had increased plasma and cerebrospinal fluid tau concentrations, induced myelin loss, and hyperphosphorylated tau pathology in the ipsilateral hippocampus and cerebral hemisphere. These findings demonstrate a relationship between cerebrovascular disease, operationalized as white matter hyperintensities, and tau levels, indexed in the plasma, suggesting that hypoperfusive injury promotes tau pathology. This potential causal association is supported by the demonstration that transient cerebral artery occlusion induces white matter damage, increases biofluidic markers of tau, and promotes cerebral tau hyperphosphorylation in older-adult mice.
Introduction: RNS60 is an experimental treatment containing oxygen nanobubbles. RNS60 has previou... more Introduction: RNS60 is an experimental treatment containing oxygen nanobubbles. RNS60 has previously been shown to reduce neuroinflammation and increase neuronal survival in animal models of multiple sclerosis, amyotrophic lateral sclerosis (ALS), Alzheimer's and Parkinson’s diseases, and traumatic brain injury. RNS60 is in phase 2 clinical testing as a treatment for ALS and acute ischemic stroke. Since RNS60 is protective in a variety of pathophysiological conditions that activate neurodegeneration, we evaluated whether RNS60 can reduce brain injury and rescue cognitive functions in a mouse model of ischemic stroke. Methods: Male C57BL/6J mice (4 months old) were subjected to transient (60 min) occlusion of the middle cerebral artery (tMCAo) followed by reperfusion, or sham surgery. We investigated the effects of post-stroke RNS60 treatment for 3 or 13 days (beginning 1 hour after reperfusion, 0.2 mL administered i.p., 1/day). Two control treatments (normal saline or oxygenated saline without nanobubbles) were used for comparison. Experimenters were blinded to the treatment groups throughout the study. To assess the post-stroke effects of RNS60 treatments, we performed multiple neurobehavioral tests that included modified neurological severity score (mNSS), novel object recognition (NOR), active place avoidance (APA), and the conflict variant of APA. Brains were collected for assessment of infarct volumes or for immunofluorescence measurements of amyloid, neurons, microglia, and axons. Results: Three days of treatment with RNS60 reduced brain infarction, edema, sensory-motor, and cognitive deficits. Thirteen days of treatment reduced brain infarction, amyloid pathology, neuronal cell death, microglial activation, and white matter damage. Noteworthy behavioral effects included recovery of memory during NOR and cognitive flexibility in the APA conflict variant. Conclusion: RNS60 treated mice exhibit significant acute and chronic protection of brain cells and neurobehavior after experimental stroke. Our data support the evaluation of RNS60 in clinical stroke trials.
White matter pathologies are critically involved in the etiology of vascular cognitive impairment... more White matter pathologies are critically involved in the etiology of vascular cognitive impairment-dementia (VCID), Alzheimer's disease (AD), and Alzheimer's disease and related diseases (ADRD), and therefore need to be considered a treatable target (Roseborough A, Hachinski V, Whitehead S. White matter degeneration-a treatable target?
Digital therapeutics is an evidence-based intervention using high-quality software, with the sole... more Digital therapeutics is an evidence-based intervention using high-quality software, with the sole purpose of treatment. As many healthcare systems are encountering high demands of quality outcomes, the need for digital therapeutics is gradually increasing in the clinical field. We conducted review of the implications of digital therapeutics in the treatment of neurological deficits for stroke patients. The implications of digital therapeutics have been discussed in four domains: cognition, speech and aphasia, motor, and vision. It was evident that different forms of digital therapeutics such as online platforms, virtual reality trainings, and iPad applications have been investigated in many trials to test its feasibility in clinical use. Although digital therapeutics may deliver high-quality solutions to healthcare services, the medicalization of digital therapeutics is accompanied with many limitations. Clinically validated digital therapeutics should be developed to prove its efficacy in stroke rehabilitation.
Background and Purpose: Interleukin-1lj is a proinflammatory cytokine produced by blood-borne and... more Background and Purpose: Interleukin-1lj is a proinflammatory cytokine produced by blood-borne and resident brain inflammatory cells. The present study was conducted to determine if interleukin-13 mRNA was produced in the brain of rats subjected to permanent focal ischemia. Methods: Rat interleukin-lj cDNA, synthesized from stimulated rat peritoneal macrophage RNA by reverse transcription and polymerase chain reaction and cloned in plasmid Bluescript KS+, was used to evaluate the expression of interleukin-1.3 mRNA in cerebral cortex from spontaneously hypertensive rats and normotensive rats subjected to permanent middle cerebral artery occlusion. Interleukin-1f3 mRNA was quantified by Northern blot analysis and compared with rat macrophage RNA standard. To correct for gel loading, blots were also analyzed with cyclophilin cDNA, which encodes an abundant, conserved protein that was unchanged by the experimental conditions. Results: Interleukin-10 mRNA produced in the ischemic zone was significantly increased from 6 hours to 120 hours, with a maximum of 211±24% of interleukin-lf reference standard, ie, 0.2 ng stimulated rat macrophage RNA, mRNA compared with the level in nonischemic cortices (4±2%) at 12 hours after ischemia (P<.01; n=6). Interleukin-1f3 mRNA at 12 hours after ischemia was markedly elevated in hypertensive rats over levels found in two normotensive rat strains. Neurological deficits were also apparent only in the hypertensive rats. Conclusions: Brain interleukin-1j3 mRNA is elevated acutely after permanent focal ischemia and especially in hypertensive rats. These data suggest that this potent proinflammatory and procoagulant cytokine might have a role in brain damage following ischemia. (Stroke. 1993;24:1746-1751.) KEY WoRDs * cerebral ischemia * cytokines * neuronal damage * rats I nterleukin-1,3 (IL-1,3) is a cytokine with multiple proinflammatory, procoagulant, and cell growth modulatory actions.' The presence of ILl ,3 in the central nervous system is believed to reflect synthesis by diverse cells such as endothelium, microglia, astrocytes, and neurons.2
Image Analyses: The perfusion delay index (PDI) was calculated from the 4 ipsilateral areas and t... more Image Analyses: The perfusion delay index (PDI) was calculated from the 4 ipsilateral areas and their corresponding contralateral counterparts using the DWI image as a reference. Of these four areas, three were chosen in the cortical region and one in the striatal region. The PDI index was defined as a ratio of the mean signal intensity in the ipsilateral area to that in the contralateral counterpart and expressed as a percentage. This calculation was done only at that instance of time when the contrast uptake was maximal in the contralateral hemisphere. Analysis of variance was used followed by appropriate post-hoc comparisons with p<0.05 considered significant. Results A representative graph showing the perfusion delay index (PDI) at one cortical region is shown in Fig 1. In all the three cortical regions evaluated, we found significant differences between vehicle and 10 ug/kg/min SB-234551 group in the perfusion delay index (PDI). The 3 ug/kg/min group did not show a significa...
American Journal of Physiology-Gastrointestinal and Liver Physiology, 1990
Increased fecal pellet output that occurs during cold-restraint stress (CRS) was evaluated system... more Increased fecal pellet output that occurs during cold-restraint stress (CRS) was evaluated systematically. Free-feeding rats, which exhibit a reduced occurrence of gastric ulcers under these conditions, were studied. CRS significantly increased fecal pellet production and fluid content. However, the fecal output produced during CRS was not associated with increased gut secretory activity or somatic motor activity associated with cold restraint and did not occur in anesthetized animals. Cold and restraint stress were additive in producing increased fecal output. Significant dose-related decreases in fecal output were produced by drugs that decrease gut transit (i.e., B-HT 920, clonidine, Lomotil, loperamide, and lidamidine). Anticholinergic-antisecretory drugs, antidepressants, and tranquilizers had little effect on fecal output or fluid content. Changes in gastrointestinal transit did not contribute to the increased fecal output during CRS. Transit in the lower small intestine was n...
Persistent neurobehavioral deficits and brain changes need validation for brain restoration. Two ... more Persistent neurobehavioral deficits and brain changes need validation for brain restoration. Two hours middle cerebral artery occlusion (tMCAO) or sham surgery was performed in male Sprague-Dawley rats. Neurobehavioral and cognitive deficits were measured over 10 weeks included: (1) sensory, motor, beam balance, reflex/abnormal responses, hindlimb placement, forepaw foot fault and cylinder placement tests, and (2) complex active place avoidance learning (APA) and simple passive avoidance retention (PA). Electroretinogram (ERG), hemispheric loss (infarction), hippocampus CA1 neuronal loss and myelin (Luxol Fast Blue) staining in several fiber tracts were also measured. In comparison to Sham surgery, tMCAO surgery produced significant deficits in all behavioral tests except reflex/abnormal responses. Acute, short lived deficits following tMCAO were observed for forelimb foot fault and forelimb cylinder placement. Persistent, sustained deficits for the whole 10 weeks were exhibited for motor (p,0.001), sensory (p,0.001), beam balance performance (p,0.01) and hindlimb placement behavior (p,0.01). tMCAO produced much greater and prolonged cognitive deficits in APA learning (maximum on last trial of 604683% change, p,0.05) but only a small, comparative effect on PA retention. Hemispheric loss/ atrophy was measured 10 weeks after tMCAO and cross-validated by two methods (e.g., almost identical % ischemic hemispheric loss of 33.463.5% for H&E and of 34.263.5% for TTC staining). No visual dysfunction by ERG and no hippocampus neuronal loss were detected after tMCAO. Fiber tract damage measured by Luxol Fast Blue myelin staining intensity was significant (p,0.01) in the external capsule and striatum but not in corpus callosum and anterior commissure. In summary, persistent neurobehavioral deficits were validated as important endpoints for stroke restorative research in the future. Fiber myelin loss appears to contribute to these long term behavioral dysfunctions and can be important for cognitive behavioral control necessary for complex APA learning.
Background: There are no drugs presently available to treat traumatic brain injury (TBI). A varie... more Background: There are no drugs presently available to treat traumatic brain injury (TBI). A variety of single drugs have failed clinical trials suggesting a role for drug combinations. Drug combinations acting synergistically often provide the greatest combination of potency and safety. The drugs examined (minocycline (MINO), N-acetylcysteine (NAC), simvastatin, cyclosporine A, and progesterone) had FDA-approval for uses other than TBI and limited brain injury in experimental TBI models. Methodology/Principal Findings: Drugs were dosed one hour after injury using the controlled cortical impact (CCI) TBI model in adult rats. One week later, drugs were tested for efficacy and drug combinations tested for synergy on a hierarchy of behavioral tests that included active place avoidance testing. As monotherapy, only MINO improved acquisition of the massed version of active place avoidance that required memory lasting less than two hours. MINO-treated animals, however, were impaired during the spaced version of the same avoidance task that required 24-hour memory retention. Coadministration of NAC with MINO synergistically improved spaced learning. Examination of brain histology 2 weeks after injury suggested that MINO plus NAC preserved white, but not grey matter, since lesion volume was unaffected, yet myelin loss was attenuated. When dosed 3 hours before injury, MINO plus NAC as single drugs had no effect on interleukin-1 formation; together they synergistically lowered interleukin-1 levels. This effect on interleukin-1 was not observed when the drugs were dosed one hour after injury. Conclusions/Significance: These observations suggest a potentially valuable role for MINO plus NAC to treat TBI.
Background: Thromboembolism is a major cause of events in carotid artery (CA) disease and predisp... more Background: Thromboembolism is a major cause of events in carotid artery (CA) disease and predisposes the dissemination of clots to upstream ischemic strokes. Although diagnostic methods are available to define thromboembolic strokes (CT, MRI, etc.), there is no technology to provide ambulatory assessment to ‘content image’ thrombi within the CA bifurcation free of the hospital setting. To address this unmet medical need we bioengineered the joining of the disintegrin bitistatin (Bit) to fluorescent NanoDiamond Particles (F-NDP) in order to bind to and non-invasively image vascular clots. F-NDP-Bit preferentially binds to the human platelet fibrinogen receptor (GPIIB/IIIA). F-NDP-Bit was systematically evaluated for NIR emission capacity in various tissues and demonstrated penetration of NIR fluorescence across distances similar to the distance from the human skin surface to the CA bifurcation. Methods: In vitro studies were conducted to evaluate binding of F-NDP-Bit to purified human GPIIB/IIIA. Also, the ability of the F-NDP-Bit to bind to vascular clots In Vivo was investigated in rat FeCl3-induced internal CA coagulation. Results: Using the specific GPIIB/IIIA antagonist lotrafiban, In Vitro specific and concentration-related F-NDP-Bit binding was demonstrated. In Vivo , intravenous administration of F-NDP-Bit during the evolution of FeCl3-induced internal CA thrombosis resulted in the dose-related clot accumulation of F-NDP-Bit that was cross-validated by three independent methods (all measures were significant as described; p &amp;lt; 0.05): ( 1 ) In Situ whole rat imaging via In Vivo Imaging System (IVIS: using Ex 54 nm; Em 695-770 nm); ( 2 ) Ex Vivo whole vessel/clot imaging (Scanning Confocal Microscopy), and ( 3 ) Extract, isolate and quantitate F-NDP-Bit following internal CA clot dissolution (12N HNO3) and direct counting (hemocytometer). Conclusions: These data indicate that F-NDP-Bit might address the need for fast, safe and highly affordable ambulatory imaging of vascular clot burden. Functionalization of F-NDP with selective ligands that can be pathognomonic for many disease situations also could facilitate risk assessment, earlier intervention and preventative medicine.
Journal of Cerebral Blood Flow and Metabolism, Nov 1, 1998
Brief occlusion of the middle cerebral artery (i.e., ischemic preconditioning; PC) induces signif... more Brief occlusion of the middle cerebral artery (i.e., ischemic preconditioning; PC) induces significant brain protec tion to subsequent severe ischemic events. In an effort to dis cover genes responsible for ischemic tolerance, we have ap plied a new technique, suppression subtractive hybridization (SSH), to identify genes that are upregulated by Pc. Using this SSH approach, a cDNA that encodes tissue inhibitor of matrix metalloproteinase-l (TIMP-l) was identified. Time course studies using Northern analysis revealed that TIMP-l mRNA was significantly elevated at 24 hours (3.3-fold over controls, P
Background: Mice expressing mutated hAPP in the entorhinal cortex (EC) display, hypersynchrony of... more Background: Mice expressing mutated hAPP in the entorhinal cortex (EC) display, hypersynchrony of the EC-hippocampus circuit, caused by decreased inhibitory tone (Angulo et al., NBD 2017). A similar EC inhibitory failure was also observed in mice expressing hAPOE4, (Nuriel et al., Nat Neursc 2017). Here we evaluated changes in EC
After an acute ischemia/reperfusion of the rat retina, the activation of cytotoxic proteases, inc... more After an acute ischemia/reperfusion of the rat retina, the activation of cytotoxic proteases, including calpain, results in necrosis and apoptosis of retinal ganglion cells resulting in their degeneration. Using a systemically administered calpain inhibitor that crosses the blood-retinal barrier would provide for novel systemic intervention that protects the retina from acute injury and loss of function. Herein, we study a novel calpain peptide inhibitor, cysteic-leucyl-argininal (CYLA), in an in-vivo rat model of retinal ischemia to determine functional protection using electroretinography. The CYLA prodrug was administered intraperitoneally before and/or after ischemia-reperfusion at concentrations of 20-40 mg/kg. We found that administering 20 mg/kg of CYLA only after ischemia provides significant preservation of retinal function.
We describe here the cloning and characterization of a rat homolog of the chemokine receptor CXCR... more We describe here the cloning and characterization of a rat homolog of the chemokine receptor CXCR3. The predicted amino acid sequence of rat CXCR3 contains 367 amino acid residues, sharing 96 and 87% amino acid sequence identity to the murine and human CXCR3, respectively. Among a large panel of chemokines tested, only interferon-inducible protein-10 (IP-10), interferon-gamma-induced monokine, and interferon-inducible T cell alpha-chemoattractant demonstrated specific abilities to induce an intracellular calcium mobilization response in human embryonic kidney 293 cells transfected with rat CXCR3 expression vector. (125)I-IP-10 competition binding studies to the CXCR3-transfected human embryonic kidney 293 cells demonstrated that human IP-10 and interferon-inducible T cell alpha-chemoattractant are more potent ligands than human interferon-gamma-induced monokine. Following our previous observation for the induced expression of IP-10 in focal stroke, we demonstrate here the time-dependent up-regulation of CXCR3 mRNA in the rat ischemic cortex after permanent occlusion of the middle cerebral artery. A significant increase in (125)I-IP-10-specific binding to ischemic cerebral cortical samples was obtained and paralleled the increase in CXCR3 mRNA expression. The changes in receptor expression and ligand binding correlate highly with known changes in leukocyte accumulation, and gliosis occurred after focal stroke. These data suggest that CXCR3/IP-10 may be a potential novel therapeutic target in focal stroke. In addition, the cloning of rat CXCR3 provides an important tool for the investigation of the pathophysiological role of CXCR3 in other rodent disease models.
Small vessel cerebrovascular disease, visualized as white matter hyperintensities on T2-weighted ... more Small vessel cerebrovascular disease, visualized as white matter hyperintensities on T2-weighted magnetic resonance imaging, contributes to the clinical presentation of Alzheimer's disease. However, the extent to which cerebrovascular disease represents an independent pathognomonic feature of Alzheimer's disease or directly promotes Alzheimer's pathology is unclear. The purpose of this study was to examine the association between white matter hyperintensities and plasma levels of tau and to determine if white matter hyperintensities and tau levels interact to predict Alzheimer's disease diagnosis. To confirm that cerebrovascular disease promotes tau pathology, we examined tau fluid biomarker concentrations and pathology in a mouse model of ischaemic injury. Three hundred ninety-one participants from the Alzheimer's Disease Neuroimaging Initiative (74.5 6 7.1 years of age) were included in this cross-sectional analysis. Participants had measurements of plasma total-tau, cerebrospinal fluid beta-amyloid, and white matter hyperintensities, and were diagnosed clinically as Alzheimer's disease (n ¼ 97), mild cognitive impairment (n ¼ 186) or cognitively normal control (n ¼ 108). We tested the relationship between plasma tau concentration and white matter hyperintensity volume across diagnostic groups. We also examined the extent to which white matter hyperintensity volume, plasma tau, amyloid positivity status and the interaction between white matter hyperintensities and plasma tau correctly classifies diagnostic category. Increased white matter hyperintensity volume was associated with higher plasma tau concentration, particularly among those diagnosed clinically with Alzheimer's disease. Presence of brain amyloid and the interaction between plasma tau and white matter hyperintensity volume distinguished Alzheimer's disease and mild cognitive impairment participants from controls with 77.6% and 63.3% accuracy, respectively. In 63 Alzheimer's Disease Neuroimaging Initiative participants who came to autopsy (82.33 6 7.18 age at death), we found that higher degrees of arteriosclerosis were associated with higher Braak staging, indicating a positive relationship between cerebrovascular disease and neurofibrillary pathology. In a transient middle cerebral artery occlusion mouse model, aged mice that received transient middle cerebral artery occlusion, but not sham surgery, had increased plasma and cerebrospinal fluid tau concentrations, induced myelin loss, and hyperphosphorylated tau pathology in the ipsilateral hippocampus and cerebral hemisphere. These findings demonstrate a relationship between cerebrovascular disease, operationalized as white matter hyperintensities, and tau levels, indexed in the plasma, suggesting that hypoperfusive injury promotes tau pathology. This potential causal association is supported by the demonstration that transient cerebral artery occlusion induces white matter damage, increases biofluidic markers of tau, and promotes cerebral tau hyperphosphorylation in older-adult mice.
Introduction: RNS60 is an experimental treatment containing oxygen nanobubbles. RNS60 has previou... more Introduction: RNS60 is an experimental treatment containing oxygen nanobubbles. RNS60 has previously been shown to reduce neuroinflammation and increase neuronal survival in animal models of multiple sclerosis, amyotrophic lateral sclerosis (ALS), Alzheimer&#39;s and Parkinson’s diseases, and traumatic brain injury. RNS60 is in phase 2 clinical testing as a treatment for ALS and acute ischemic stroke. Since RNS60 is protective in a variety of pathophysiological conditions that activate neurodegeneration, we evaluated whether RNS60 can reduce brain injury and rescue cognitive functions in a mouse model of ischemic stroke. Methods: Male C57BL/6J mice (4 months old) were subjected to transient (60 min) occlusion of the middle cerebral artery (tMCAo) followed by reperfusion, or sham surgery. We investigated the effects of post-stroke RNS60 treatment for 3 or 13 days (beginning 1 hour after reperfusion, 0.2 mL administered i.p., 1/day). Two control treatments (normal saline or oxygenated saline without nanobubbles) were used for comparison. Experimenters were blinded to the treatment groups throughout the study. To assess the post-stroke effects of RNS60 treatments, we performed multiple neurobehavioral tests that included modified neurological severity score (mNSS), novel object recognition (NOR), active place avoidance (APA), and the conflict variant of APA. Brains were collected for assessment of infarct volumes or for immunofluorescence measurements of amyloid, neurons, microglia, and axons. Results: Three days of treatment with RNS60 reduced brain infarction, edema, sensory-motor, and cognitive deficits. Thirteen days of treatment reduced brain infarction, amyloid pathology, neuronal cell death, microglial activation, and white matter damage. Noteworthy behavioral effects included recovery of memory during NOR and cognitive flexibility in the APA conflict variant. Conclusion: RNS60 treated mice exhibit significant acute and chronic protection of brain cells and neurobehavior after experimental stroke. Our data support the evaluation of RNS60 in clinical stroke trials.
White matter pathologies are critically involved in the etiology of vascular cognitive impairment... more White matter pathologies are critically involved in the etiology of vascular cognitive impairment-dementia (VCID), Alzheimer's disease (AD), and Alzheimer's disease and related diseases (ADRD), and therefore need to be considered a treatable target (Roseborough A, Hachinski V, Whitehead S. White matter degeneration-a treatable target?
Digital therapeutics is an evidence-based intervention using high-quality software, with the sole... more Digital therapeutics is an evidence-based intervention using high-quality software, with the sole purpose of treatment. As many healthcare systems are encountering high demands of quality outcomes, the need for digital therapeutics is gradually increasing in the clinical field. We conducted review of the implications of digital therapeutics in the treatment of neurological deficits for stroke patients. The implications of digital therapeutics have been discussed in four domains: cognition, speech and aphasia, motor, and vision. It was evident that different forms of digital therapeutics such as online platforms, virtual reality trainings, and iPad applications have been investigated in many trials to test its feasibility in clinical use. Although digital therapeutics may deliver high-quality solutions to healthcare services, the medicalization of digital therapeutics is accompanied with many limitations. Clinically validated digital therapeutics should be developed to prove its efficacy in stroke rehabilitation.
Background and Purpose: Interleukin-1lj is a proinflammatory cytokine produced by blood-borne and... more Background and Purpose: Interleukin-1lj is a proinflammatory cytokine produced by blood-borne and resident brain inflammatory cells. The present study was conducted to determine if interleukin-13 mRNA was produced in the brain of rats subjected to permanent focal ischemia. Methods: Rat interleukin-lj cDNA, synthesized from stimulated rat peritoneal macrophage RNA by reverse transcription and polymerase chain reaction and cloned in plasmid Bluescript KS+, was used to evaluate the expression of interleukin-1.3 mRNA in cerebral cortex from spontaneously hypertensive rats and normotensive rats subjected to permanent middle cerebral artery occlusion. Interleukin-1f3 mRNA was quantified by Northern blot analysis and compared with rat macrophage RNA standard. To correct for gel loading, blots were also analyzed with cyclophilin cDNA, which encodes an abundant, conserved protein that was unchanged by the experimental conditions. Results: Interleukin-10 mRNA produced in the ischemic zone was significantly increased from 6 hours to 120 hours, with a maximum of 211±24% of interleukin-lf reference standard, ie, 0.2 ng stimulated rat macrophage RNA, mRNA compared with the level in nonischemic cortices (4±2%) at 12 hours after ischemia (P<.01; n=6). Interleukin-1f3 mRNA at 12 hours after ischemia was markedly elevated in hypertensive rats over levels found in two normotensive rat strains. Neurological deficits were also apparent only in the hypertensive rats. Conclusions: Brain interleukin-1j3 mRNA is elevated acutely after permanent focal ischemia and especially in hypertensive rats. These data suggest that this potent proinflammatory and procoagulant cytokine might have a role in brain damage following ischemia. (Stroke. 1993;24:1746-1751.) KEY WoRDs * cerebral ischemia * cytokines * neuronal damage * rats I nterleukin-1,3 (IL-1,3) is a cytokine with multiple proinflammatory, procoagulant, and cell growth modulatory actions.' The presence of ILl ,3 in the central nervous system is believed to reflect synthesis by diverse cells such as endothelium, microglia, astrocytes, and neurons.2
Image Analyses: The perfusion delay index (PDI) was calculated from the 4 ipsilateral areas and t... more Image Analyses: The perfusion delay index (PDI) was calculated from the 4 ipsilateral areas and their corresponding contralateral counterparts using the DWI image as a reference. Of these four areas, three were chosen in the cortical region and one in the striatal region. The PDI index was defined as a ratio of the mean signal intensity in the ipsilateral area to that in the contralateral counterpart and expressed as a percentage. This calculation was done only at that instance of time when the contrast uptake was maximal in the contralateral hemisphere. Analysis of variance was used followed by appropriate post-hoc comparisons with p<0.05 considered significant. Results A representative graph showing the perfusion delay index (PDI) at one cortical region is shown in Fig 1. In all the three cortical regions evaluated, we found significant differences between vehicle and 10 ug/kg/min SB-234551 group in the perfusion delay index (PDI). The 3 ug/kg/min group did not show a significa...
American Journal of Physiology-Gastrointestinal and Liver Physiology, 1990
Increased fecal pellet output that occurs during cold-restraint stress (CRS) was evaluated system... more Increased fecal pellet output that occurs during cold-restraint stress (CRS) was evaluated systematically. Free-feeding rats, which exhibit a reduced occurrence of gastric ulcers under these conditions, were studied. CRS significantly increased fecal pellet production and fluid content. However, the fecal output produced during CRS was not associated with increased gut secretory activity or somatic motor activity associated with cold restraint and did not occur in anesthetized animals. Cold and restraint stress were additive in producing increased fecal output. Significant dose-related decreases in fecal output were produced by drugs that decrease gut transit (i.e., B-HT 920, clonidine, Lomotil, loperamide, and lidamidine). Anticholinergic-antisecretory drugs, antidepressants, and tranquilizers had little effect on fecal output or fluid content. Changes in gastrointestinal transit did not contribute to the increased fecal output during CRS. Transit in the lower small intestine was n...
Persistent neurobehavioral deficits and brain changes need validation for brain restoration. Two ... more Persistent neurobehavioral deficits and brain changes need validation for brain restoration. Two hours middle cerebral artery occlusion (tMCAO) or sham surgery was performed in male Sprague-Dawley rats. Neurobehavioral and cognitive deficits were measured over 10 weeks included: (1) sensory, motor, beam balance, reflex/abnormal responses, hindlimb placement, forepaw foot fault and cylinder placement tests, and (2) complex active place avoidance learning (APA) and simple passive avoidance retention (PA). Electroretinogram (ERG), hemispheric loss (infarction), hippocampus CA1 neuronal loss and myelin (Luxol Fast Blue) staining in several fiber tracts were also measured. In comparison to Sham surgery, tMCAO surgery produced significant deficits in all behavioral tests except reflex/abnormal responses. Acute, short lived deficits following tMCAO were observed for forelimb foot fault and forelimb cylinder placement. Persistent, sustained deficits for the whole 10 weeks were exhibited for motor (p,0.001), sensory (p,0.001), beam balance performance (p,0.01) and hindlimb placement behavior (p,0.01). tMCAO produced much greater and prolonged cognitive deficits in APA learning (maximum on last trial of 604683% change, p,0.05) but only a small, comparative effect on PA retention. Hemispheric loss/ atrophy was measured 10 weeks after tMCAO and cross-validated by two methods (e.g., almost identical % ischemic hemispheric loss of 33.463.5% for H&E and of 34.263.5% for TTC staining). No visual dysfunction by ERG and no hippocampus neuronal loss were detected after tMCAO. Fiber tract damage measured by Luxol Fast Blue myelin staining intensity was significant (p,0.01) in the external capsule and striatum but not in corpus callosum and anterior commissure. In summary, persistent neurobehavioral deficits were validated as important endpoints for stroke restorative research in the future. Fiber myelin loss appears to contribute to these long term behavioral dysfunctions and can be important for cognitive behavioral control necessary for complex APA learning.
Background: There are no drugs presently available to treat traumatic brain injury (TBI). A varie... more Background: There are no drugs presently available to treat traumatic brain injury (TBI). A variety of single drugs have failed clinical trials suggesting a role for drug combinations. Drug combinations acting synergistically often provide the greatest combination of potency and safety. The drugs examined (minocycline (MINO), N-acetylcysteine (NAC), simvastatin, cyclosporine A, and progesterone) had FDA-approval for uses other than TBI and limited brain injury in experimental TBI models. Methodology/Principal Findings: Drugs were dosed one hour after injury using the controlled cortical impact (CCI) TBI model in adult rats. One week later, drugs were tested for efficacy and drug combinations tested for synergy on a hierarchy of behavioral tests that included active place avoidance testing. As monotherapy, only MINO improved acquisition of the massed version of active place avoidance that required memory lasting less than two hours. MINO-treated animals, however, were impaired during the spaced version of the same avoidance task that required 24-hour memory retention. Coadministration of NAC with MINO synergistically improved spaced learning. Examination of brain histology 2 weeks after injury suggested that MINO plus NAC preserved white, but not grey matter, since lesion volume was unaffected, yet myelin loss was attenuated. When dosed 3 hours before injury, MINO plus NAC as single drugs had no effect on interleukin-1 formation; together they synergistically lowered interleukin-1 levels. This effect on interleukin-1 was not observed when the drugs were dosed one hour after injury. Conclusions/Significance: These observations suggest a potentially valuable role for MINO plus NAC to treat TBI.
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