Quan Jiang - US grants

DESCRIPTION (Adapted from Applicant's Abstract): This application will develop magnetic resonance imaging (MRI) criteria to predict outcome of thrombolysis after focal cerebral embolic ischemia in rats. The goal of this proposal is to assess whether the MRI measurements can identify reversibly damaged tissue and identify cerebral tissue that is destined to hemorrhage when treated with a thrombolytic agent. The applicants would also investigate whether the efficacy of thrombolytic intervention can be characterized and predicted by quantitative changes in MRI measurable parameters. Two specific aims are proposed: Specific Aim 1-To predict hemorrhagic transformation (HT) after embolic stroke and thrombolysis in rats using MRI. Specific Aim 2a-To identify reversibly damaged ischemic tissue after embolic stroke and thrombolysis in rat using MRI. Specific Aim 2b B To determine the ability of MRI to predict the efficacy of thrombolytic intervention with rt-PA. The applicants would employ multimodality MRI and image analysis methodology in combination with histological endpoints to characterize cerebral tissue subjected to embolic stroke and to predict outcome of thrombolytic therapy. The long-term goal is to provide new and important information relevant to the treatment of acute stroke by thrombolysis.

[unreadable] DESCRIPTION (provided by applicant): Treatment of stroke with bone marrow stromal cells (MSCs) significantly improves functional recovery in experimental stroke. However, little is known about temporal and spatial profiles of migration of transplanted MSCs and the effects of these cells on host cerebral tissue leading to functional recovery. We propose to develop noninvasive in vivo magnetic resonance (MR) methodology for tracking transplanted MSCs and investigating their effects on the host brain. In Specific Aim 1, we will first optimize methodology for magnetic contrast agent labeling and in vivo three dimensional magnetic resonance (MRI) monitoring of transplanted MSCs in the host brain. Using the optimized methodology, we will then examine the effects of different routes (intravenous vs intracisternal) of transplantation on survival, migration, and distribution patterns of transplanted cells in brain subjected to stroke. In Specific Aim 2, dynamic effects of transplanted MSCs on the host brain angiogenesis and functional recovery after stroke will be noninvasively measured by means of MR. Neurological outcome will be measured using a battery of behavioral tests. Correlation between changes in MR measurements and dynamic functional improvements will be analyzed in the same animal. In addition, changes in MR measurements of angiogenesis resulting from MSC transplantation will be verified using three dimensional laser scanning confocal microscopy in combination with immuno-histochemistry. With these novel approaches, we expect that noninvasive MR measurements will simultaneously detect the migration and distribution of transplanted cells and the effects of these cells on the host brain tissue, and that changes in MR measurements will correlate to neurological function. Therefore, MR could potentially provide important noninvasive measurements for developing a successful cell therapy for stroke. After completing our studies, we expect to demonstrate that MR tracking magnetic labeled cells is a valid new technique for studying cell therapy for stroke, which will lead to optimization of cell transplantation protocols and improved management of stroke. [unreadable] [unreadable]

brain imaging /visualization /scanning

DESCRIPTION (provided by applicant): There are two major innovative aspects to our proposal: 1) To develop magnetic resonance imaging (MRI) as a means to monitor and predict functional recovery after traumatic brain injury (TBI); and 2) To treat TBI with bone marrow stromal cells (MSCs) early, i.e. within 24 hours of injury, as a neuroprotective and neurorestorative therapy. Neurorestorative treatment of TBI using MSCs has demonstrated promise in promoting neuronal remodeling, and improvement of functional recovery. However, we and others have not studied the beneficial effects of early, within 24 hours of injury, treatment with MSCs. Also, there is a compelling need to noninvasively monitor brain remodeling and functional recovery and to translate these methodologies from experimental studies to the clinic. We propose that MRI can sensitively monitor ongoing structural remodeling of brain tissue after TBI that reflects neurological function, and therefore, MRI can be employed to assess recovery and ultimately be applied to the TBI patient. In this proposal, we will develop and implement MR methodologies to investigate the effects of early and late MSC treatment on the migration and distribution of MSCs and lesion volume after TBI (Aim 1), neurite reorganization (Aim 2), and the relationship between brain remodeling and functional recovery (Aim 3) in the experimental animal subjected to TBI. MRI measurements of brain remodeling will be verified using three dimensional laser scanning confocal microscopy and immuno-histochemistry. Neurological outcome will be assessed using a battery of behavioral tests. With these novel approaches, we expect that MRI methodologies for measurement of distribution and concentration of MSCs and neurite reorganization are valid new tools for monitoring the recovery from TBI after restorative therapy. These methods should lead to optimization of treatment protocols and improved management of recovery from TBI.

? DESCRIPTION (provided by applicant): Type II diabetes mellitus (T2DM) is a common metabolic disease and an established risk factor for cognitive dysfunction in the elderly population. However, the pathological mechanisms that underpin the development and progression of DM-related deficits remain unclear. Recent investigations1-4 have altered the traditional model of cerebrospinal fluid (CSF) hydrodynamics. The brain lacks specialized organ-wide anatomic structure to facilitate lymphatic clearance although the brain has complex architecture and high metabolic activity. However, a newly identified glymphatic system has been shown to modulate the CSF-interstitial (ISF) exchange, which facilitates clearance of interstitial solute from the brain parenchyma. Impairment of the glymphatic system is involved with the development of neurodegenerative conditions, including Alzheimers disease and sleep disorders, etc2, 4. Although the impact of the glymphatic system is being investigated in Alzheimers disease and sleep disorders, with promising results, there are no reported data related to diabetes and the glymphatic system. Using a model of T2DM in middle-aged rats and noninvasive MRI methodologies, our preliminary data indicate that compared with age-matched non-DM rats, the T2DM rats reduced clearance rate of interstitial Gd-DTPA agent from brain parenchyma by approximately 84 % and increased clearance time by 4.2 time of Non-DM rats in the hippocampus, leading to accumulation of Gd-DTPA agent in these regions and consequently high MRI signal intensity in T1 weighted MRI (T1WI). In parallel, ex-vivo confocal imaging analysis revealed that in Non-DM rats, the concentration of interstitial Texas Red-conjugated dextran (TR-3, MW 3kD) reached a plateau in the brain interstitium approximately 3h after injecting TR-3 into the cisterna magna and after that TR-3 began to clear and was almost completely cleared from brain parenchyma at 6h after the injection, whereas in middle-age T2DM rats TR-3 accumulated in the hippocampal interstitium with time and exhibited strong fluorescent signals at 6h after the injection. These ex-vivo data are consistent with in vivo MRI findings, indicating that T2DM impairs the glymphatic clearance of interstitial solutes in the brain. In addition, T2DM rats exhibited microvascular thrombosis and blood brain barrier (BBB) leakage in the hippocampus in immunofluorescent analysis and also showed spatial learning deficits compared to Non-DM rats. Based on our novel preliminary data, we will employ MRI and 3D confocal microscopy to evaluate for the first time, temporal and spatial profiles of paravascular CSF-ISF exchange throughout the brain during the development of T2DM. We propose to further develop MRI protocol and analysis modeling as an effective means to evaluate the function and status of the glymphatic system (Aim 1). We will then use the optimized MRI protocol and analysis to explore the relationships between impairment of glymphatic system, vascular damage, and functional deficits during develop of DM (Aim 2). Data generated from this application will provide new insights into the progression of DM associated impairment of the glymphatic system.

ABSTRACT The objective of this application is to investigate glymphatic impairment and cognitive deficits during progression of aging with and without diabetes. Emerging data1-5 indicate that the glymphatic system in the brain mediates the cerebrospinal fluid (CSF)-interstitial (ISF) exchange and solute clearance from the brain parenchyma. However, despite the well-described dysfunction of the glymphatic system in the development of neurodegenerative conditions, there is still no reported study that focuses on the role of the glymphatic system in the development of cognitive impairment during aging and aging with type-2 diabetes (DM). Using non- invasive MRI methodologies to investigate cerebral solute waste clearance in middle-age control and type-2 diabetic (DM) rats, we have found increased impairment of the glymphatic system, as indicated by reduced clearance of interstitial Gd-DTPA in brain parenchyma, primarily in the hippocampus and hypothalamus in DM rats (Fig.2&3)6. In parallel, 3D confocal microscopic analysis of the brain-wide distribution of fluorescent tracers revealed increased delayed clearance of ISF in the hippocampus and hypothalamus from DM rats (Fig.2&3)6. Impairment of the glymphatic system in DM rats was shown to be highly correlated with cognitive deficits as measured by an array of cognitive tests including the Morris Water Maze (MWM) for hippocampal related learning and memory. Importantly, histopathological analysis shows that delayed clearance of interstitial solutes is associated with sporadic cerebral microvascular thrombosis in the hippocampus 2 months after hyperglycemia (15 months from birth), while extensive microvascular thrombosis and para-vascular accumulation of beta- amyloid (A?) are detected at 4 months after induction of hyperglycemia (17 months from birth), suggesting that the impairment of the glymphatic system leads to A? accumulation. Collectively, our preliminary data, for the first time, demonstrate that non-invasive MRI methodologies can detect DM-induced early impairment of the glymphatic system which is highly correlated with hippocampal related dysfunction of learning and memory. Based on our novel preliminary data, we will employ MRI and 3D confocal microscopy to evaluate and quantitatively measure kinetic clearance parameters of the glymphatic system during progression of aging with and without DM (Aim 1). We will then investigate: whether impairment of the glymphatic system predicts cognitive dysfunction, the sensitivity and association between impairment of the glymphatic system, the onset of brain vascular dysfunction, and cognitive deficits during aging with and without DM (Aim 2). Data generated from this application will provide new insights into aging and age-matched DM associated impairment of the glymphatic system and the relationship of the glymphatic system with vascular and cognitive dysfunction.

ABSTRACT Ischemic stroke patients with Diabetes mellitus (DM) exhibit a distinct risk-factor and etiologic profile and a worse neurovascular prognosis than non-DM patients. Therefore, there is a compelling need to investigate neurovascular changes after stroke in the DM and non-DM population and to develop therapeutic approaches specifically designed to reduce neurological deficits after stroke. Type 2 diabetes (T2DM) constitutes 90% of diabetic patients and is associated with low high-density lipoprotein cholesterol (HDL-C), impairment of the anti-oxidative capacity of HDL-C, low phosphorylation of endothelial nitric oxide synthase (p-eNOS), and with reduced ATP-binding cassette transporter A1 (ABCA1) gene expression. D-4F is an economical apolipoprotein A-I (ApoA-I) mimetic peptide, presently employed in clinical trials to reduce coronary atherosclerosis in patients with acute coronary syndrome. However, the therapeutic effects of D-4F in post-ischemic stroke have not been investigated. Our preliminary data show that D-4F treatment of stroke starting 2h or 24h after ischemic stroke improves recovery of neurological function in both T2DM and non-DM mice and also increases p-eNOS and ABCA1 in the ischemic brain. In a novel and clinically relevant approach, based on our robust preliminary data, we propose to use D-4F in the treatment of stroke in the non-DM and T2DM population in mice. We seek to develop D-4F as a novel neurorestorative therapy to reduce white matter (WM) dysfunction and vascular damage, in T2DM and non-DM mice when treatment is initiated at 24h after onset of ischemic stroke. In addition, most development of stroke treatments has focused on young adult animals, but not on old animals, the prevalent population with stroke. Increased age also increases neurological impairment after stroke. We have also developed and implemented multimodality MRI imaging which can dynamically monitor neurovascular remodeling in both the animal and the patient. In the current study, we will measure WM and vascular changes and elucidate the mechanisms of action of D-4F in young adult and aged animals with and without T2DM after stroke. Our hypothesis is that D-4F increases ABCA1 and p-eNOS signaling activity which mediates vascular and WM remodeling and in concert improve functional outcome after stroke. We, therefore, propose two highly integrated and longitudinally designed Specific Aims. Aim 1 will investigate the delayed (24h after stroke) therapeutic effects of D-4F in non-DM and T2DM in young adult and aged mice after stroke. The differences in cerebral WM and vascular changes, and neurological functional outcome after stroke between non-DM and T2DM mice treated with or without D-4F will be analyzed. MRI will be employed to measure the dynamics of neurovascular reorganization underlying therapeutic response and recovery. In Aim 2, using eNOS knockout mice and specific loss of brain ABCA1 mice, we will investigate the mechanisms by which D-4F promotes neurovascular remodeling and hence, neurological recovery. The long-term objective of this RO1 is to develop a neurorestorative treatment for stroke in patients with or without diabetes.

ABSTRACT The objective of this application is to first develop and validate microvessel measurement for the entire brain to enhance detection sensitivity of microvessels by ten-fold using superparamagnetic iron oxide (SPIO) enhanced susceptibility weighted imaging (SWI, SPIO-SWI) and then to investigate the interaction between glymphatic and vascular systems for waste clearance in the diabetic brain. Emerging data indicate that the glymphatic system in the brain mediates the cerebrospinal fluid (CSF)-interstitial (ISF) exchange and solute clearance from the brain parenchyma and plays an important role in neurological diseases1-6. Despite many milestone achievements, conclusive findings on the solute efflux pathways are relatively limited. Consequently, the interaction between vascular and glymphatic systems on waste clearance, especially with neurological diseases, is unclear. The paucity of research into the efflux pathway may be attributed in part to technical difficulties, such as the challenging need to perform minimally invasive in-vivo, ultra-high detection sensitivity for tube-shaped influx and efflux pathways, and whole brain imaging. Although MRI can overcome the weak points of two-photon confocal microscopy to provide non-invasive whole brain in-vivo imaging of the glymphatic system, conventional MRI sensitivity is insufficient for the required spatial resolution for investigating microvessels of glymphatic and vascular systems. We have developed highly sensitive MRI methods (Fig. 1) which significantly improve the detection sensitivity of small vessels by using the combination of high susceptibility of MRI agents with blooming effects7-9. The new methods provide excellent tools for investigating the efflux pathways of waste clearance under normal and pathophysiological conditions. Three efflux routes have been recently proposed and solutes in the brain could reach the lymphatic network by the olfactory bulb across the ethmoid plate10, 11 or by functioning conventional lymphatic vasculature in the meninges12. We found that tracer concentration in the venous system significantly increased with diabetes (Fig. 9), thus adding a new route for brain waste clearance. Based on our novel preliminary data and published studies by others, we hypothesize that, the newly developed SPIO-SWI technique significantly increases detecting sensitivity of microvessels in both vascular and glymphatic systems, and the efflux pathways of waste clearance with and without diabetes can be identified and investigated using this optimized SPIO-SWI method. To test these hypotheses, we will first (Aim 1) further develop, optimize and validate SPIO-SWI techniques to enhance the detection sensitivity for both vascular and glymphatic microvessels. We will perform computer simulation, optimize SWI technique and experimental conditions in animal studies and then validate USPIO-SWI technique by LSCM measurements. We will then (Aim 2) investigate the interaction between vascular and glymphatic systems for waste clearance in diabetic brain using the optimized USPIO-SWI technique. Data generated from this application will provide new insights into the efflux pathways between glymphatic and vascular systems in diabetic brain.