Contribution of MLKL to the development of doxorubicin-induced cardiomyopathy and its amelioration by rapamycin.

Necroptosis, necrosis characterized by RIPK3-MLKL activation, has been proposed as a mechanism of doxorubicin (DOX)-induced cardiomyopathy. We showed that rapamycin, an mTORC1 inhibitor, attenuates cardiomyocyte necroptosis. Here we examined role of MLKL in DOX-induced myocardial damage and protective effects of rapamycin. Cardiomyopathy was induced in mice by intraperitoneal injections of DOX (10 mg/kg, every other day) and followed for 7 days. DOX-treated mice showed a significant decline in LVEF assessed by cardiac MRI (45.5 ± 5.1% vs. 65.4 ± 4.2%), reduction in overall survival rates, and increases in myocardial RIPK3 and MLKL expression compared with those in vehicle-treated mice, and those changes were prevented by administration of rapamycin (0.25 mg/kg) before DOX injection. In immunohistochemical analyses, p-MLKL signals were detected in the cardiomyocytes of DOX-treated mice, and the signals were reduced by rapamycin. Mlkl+/- and Mlkl-/- mice were similarly resistant to DOX-induced cardiac dysfunction, indicating that a modest reduction in MLKL level is sufficient to prevent the development of DOX-induced cardiomyopathy. However, evidence of cardiomyocyte necrosis assessed by C9 immunostaining, presence of replacement fibrosis, and electron microscopic analyses was negligible in the myocardium of DOX-treated mice. Thus, MLKL-mediated signaling contributes to DOX-induced cardiac dysfunction primarily by a necrosis-independent mechanism, which is inhibitable by rapamycin.

Low blood concentration of alcohol enhances activity related to stopping failure in the right inferior frontal cortex.

This study investigated the effects of low doses of alcohol, which are acceptable for driving a car, on inhibitory control and neural processing using the stop-signal task (SST) in 17 healthy right-handed social drinkers. The study employed simultaneous functional magnetic resonance imaging and electromyography (EMG) recordings to assess behavioral and neural responses under conditions of low-dose alcohol (breath-alcohol concentration of 0.15 mg/L) and placebo. The results demonstrated that even a small amount of alcohol consumption prolonged Go reaction times in the SST and modified stopping behavior, as evidenced by a decrease in the frequency and magnitude of partial response EMG that did not result in button pressing during successful inhibitory control. Furthermore, alcohol intake enhanced neural activity during failed inhibitory responses in the right inferior frontal cortex, suggesting its potential role in behavioral adaptation following stop-signal failure. These findings suggest that even low levels of alcohol consumption within legal driving limits can greatly impact both the cognitive performance and brain activity involved in inhibiting responses. This research provides important evidence on the neurobehavioral effects of low-dose alcohol consumption, with implications for understanding the biological basis of impaired motor control and decision-making and potentially informing legal guidelines on alcohol consumption.

Rehabilitation facilitates functional improvement following intravenous infusion of mesenchymal stem cells in the chronic phase of cerebral ischemia in rats.

The primary objective of this study was to investigate the potential facilitating effects of daily rehabilitation for chronic cerebral ischemia following the intravenous infusion of mesenchymal stem cells (MSC) in rats. The middle cerebral artery (MCA) was occluded by intraluminal occlusion using a microfilament (MCAO). Eight weeks after MCAO induction, the rats were used as a chronic cerebral ischemia model. Four experimental groups were studied: Vehicle group (medium only, no cells); Rehab group (vehicle + rehabilitation), MSC group (MSC only); and Combined group (MSC + rehabilitation). Rat MSCs were intravenously infused eight weeks after MCAO induction, and the rats received daily rehabilitation through treadmill exercise for 20 min. Behavioral testing, lesion volume assessment using magnetic resonance imaging (MRI), and histological analysis were performed during the observation period until 16 weeks after MCAO induction. All treated animals showed functional improvement compared with the Vehicle group; however, the therapeutic efficacy was greatest in the Combined group. The combination therapy is associated with enhanced neural plasticity shown with histological analysis and MRI diffusion tensor imaging. These findings provide behavioral evidence for enhanced recovery by combined therapy with rehabilitation and intravenous infusion of MSCs, and may form the basis for the development of clinical protocols in the future.

Repeated intravenous infusion of mesenchymal stem cells enhances recovery of motor function in a rat model with chronic spinal cord injury.

Spinal cord injury (SCI) can cause paralysis with a high disease burden with limited treatment options. A single intravenous infusion of mesenchymal stem cells (MSCs) improves motor function in rat SCI models, possibly through the induction of axonal sprouting and remyelination. Repeated infusions (thrice at weekly intervals) of MSCs were administered to rats with chronic SCI to determine if multiple-dosing regimens enhance motor improvement. Chronic SCI rats were randomized and infused with vehicle (vehicle), single MSC injection at week 6 (MSC-1) or repeatedly injections of MSCs at 6, 7, and 8 weeks (MSC-3) after SCI induction. In addition, a single high dose of MSCs (HD-MSC) equivalent to thrice the single dose was infused at week 6. Locomotor function, light and electron microscopy, immunohistochemistry and ex vivo diffusion tensor imaging were performed. Repeated infusion of MSCs (MSC-3) provided the greatest functional recovery compared to single and single high-dose infusions. The density of remyelinated axons in the injured spinal cord was the greatest in the MSC-3 group, followed by the MSC-1, HD-MSC and vehicle groups. Increased sprouting of the corticospinal tract and serotonergic axon density was the greatest in the MSC-3 group, followed by MSC-1, HD-MSC, and vehicle groups. Repeated infusion of MSCs over three weeks resulted in greater functional improvement than single administration of MSCs, even when the number of infused cells was tripled. MSC-treated rats showed axonal sprouting and remyelination in the chronic phase of SCI.

Therapeutic efficacy of intravenous infusion of mesenchymal stem cells in rat perinatal brain injury.

BACKGROUND: Perinatal brain injury is multifactorial and primarily associated with brain prematurity, inflammation, and hypoxia-ischemia. Although recent advances in perinatal medicine　have improved the survival rates of preterm infants, neurodevelopmental disorders remain a significant complication. We tested whether the intravenous infusion of mesenchymal stem cells (MSCs) had therapeutic efficacy against perinatal brain injury in rats. METHODS: Pregnant rats at embryonic day (E) 18 received lipopolysaccharide and the pups were born at E21. On postnatal day (PND) 7, the left common carotid artery of each pup was ligated, and they were exposed to 8% oxygen for 2 h. They were randomized on PND10, and MSCs or vehicle were intravenously infused. We performed behavioral assessments, measured brain volume using MRI, and performed histological analyses on PND49. RESULTS: Infused MSCs showed functional improvements in our model. In vivo MRI revealed that MSC infusion increased non-ischemic brain volume compared to the vehicle group. Histological analyses showed that cortical thickness, the number of NeuN+ and GAD67+ cells, and synaptophysin density in the non-ischemic hemisphere in the MSC group were greater than the vehicle group, but less than the control group. CONCLUSIONS: Infused MSCs improve sensorimotor and cognitive functions in perinatal brain injury and enhance neuronal growth. IMPACT: Intravenous infusion of MSCs improved neurological function in rats with perinatal brain injury, including motor, sensorimotor, cognitive, spatial, and learning memory. Infused MSCs increased residual (non-ischemic) tissue volume, number of neuronal cells, GABAergic cells, and cortical synapses in the contralesional (right) hemisphere. Intravenous administration of MSC might be suitable for the treatment of perinatal brain injury.

Microbleeds Due to Reperfusion Enhance Early Seizures after Carotid Ligation in a Rat Ischemic Model.

Impaired reperfusion in ischemic brain disease is a condition that we are increasingly confronted with owing to recent advances in reperfusion therapy. In the present study, rat models of reperfusion were investigated to determine the causes of acute seizures using magnetic resonance imaging (MRI) and histopathological specimens. Rat models of bilateral common carotid artery ligation followed by reperfusion and complete occlusion were created. We compared the incidence of seizures, mortality within 24 h, MRI, and magnetic resonance spectroscopy (MRS) to evaluate ischemic or hemorrhagic changes and metabolites in the brain parenchyma. In addition, the histopathological specimens were compared with those observed on MRI. In multivariate analysis, the predictive factors of mortality were seizure (odds ratios (OR), 106.572), reperfusion or occlusion (OR, 0.056), and the apparent diffusion coefficient value of the striatum (OR, 0.396). The predictive factors of a convulsive seizure were reperfusion or occlusion (OR, 0.007) and the number of round-shaped hyposignals (RHS) on susceptibility-weighted imaging (SWI) (OR, 2.072). The incidence of convulsive seizures was significantly correlated with the number of RHS in the reperfusion model. RHS on SWI was confirmed pathologically as microbleeds in the extravasation of the brain parenchyma and was distributed around the hippocampus and cingulum bundle. MRS analysis showed that the N-acetyl aspartate level was significantly lower in the reperfusion group than in the occlusion group. In the reperfusion model, RHS on SWI was a risk factor for convulsive seizures. The location of the RHS also influenced the incidence of convulsive seizures.

Computational Fluid Dynamics Analysis Features in Aneurysm Development in Rats.

The investigation of how to control the development and growth of cerebral aneurysms is important for the prevention of subarachnoid hemorrhage. Although there have been several types of research studies on computational fluid dynamics (CFD) analysis of brain aneurysm development and growth, there has been no unified interpretation of the CFD analysis results. The purpose of this study is to clarify the characteristics of CFD analysis results related to the development of cerebral aneurysms using an animal model. Nineteen rat models of cerebral aneurysms were created, and the CFD analysis results between the cerebral aneurysm group [n = 10; the aneurysm was observed on magnetic resonance angiography (MRA) within 10 weeks after aneurysm induction surgery] and the nonaneurysm group (n = 9) were compared. All aneurysms were confirmed on the proximal segment of the left cerebral artery (P1), and the cross-sectional area and curvature of the left P1 were evaluated together. In the cerebral aneurysm group, there was a decrease in wall shear stress (WSS) that is consistent with the location of the aneurysm compared to the nonaneurysm group. The cross-sectional area of the left P1 gradually increased in the aneurysm group but not in the nonaneurysm group. The mean curvature in the entire left P1 was higher in the aneurysm group than in the nonaneurysm group. This study revealed that the development of cerebral aneurysms is due to changes in vascular morphology, namely, an increase in vessel diameter and a high curvature, and a decreased WSS consistent with the site of aneurysm development using this animal model.

A practical protocol for high-spatial-resolution magnetic resonance angiography for cerebral arteries in rats.

BACKGROUND: Magnetic resonance angiography (MRA) is an important tool in rat models of cerebrovascular disease. Although MRA has long been used in rodents, the image quality is typically not as high as that observed in clinical practice. Moreover, studies on MRA image quality in rats are limited. This study aimed to develop a practical high-spatial-resolution MRA protocol for imaging cerebral arteries in rats. NEW METHOD: We used the "half position method" regarding coil placement and modified the imaging parameters and image reconstruction method. We applied this new imaging method to measure maturation-related signal changes on rat MRAs. RESULTS: The new practical high-spatial-resolution MRA imaging protocol obtained a signal intensity up to 3.5 times that obtained using a basic coil system, simply by modifying the coil placement method. This method allowed the detection of a gradual decrease in the signal in cerebral vessels with maturation. COMPARISON WITH EXISTING METHODS: A high-spatial-resolution MRA for rats was obtained with an imaging time of approximately 100 min. Comparable resolution and image quality were obtained using the new protocol with an imaging time of 30 min CONCLUSIONS: The new practical high-spatial-resolution MRA protocol can be implemented simply and successfully to achieve high image quality with an imaging time of approximately 30 min. This protocol will benefit researchers performing MRA imaging in cerebral artery studies in rats.

Accuracy of computed tomography: magnetic resonance imaging image fusion using a phantom for skull base surgery.

BACKGROUND: The aim of this study is to assess the positional accuracy of image fusions of the skull base region using different magnetic resonance imaging (MRI) and computed tomography (CT) image pairs. METHODS: An image set of 3D fast imaging employing steady-state acquisition-C (FIESTA-C) was used as the base image set. Image fusions were performed using an image set with different fields of view (FOVs): one with different matrix size, one with a different sequence of 3D spoiled gradient recalled acquisition, and one with different modality (CT), using a phantom including multi columnar objects. Position of columns at the center, and 4 and 8 cm from the center were measured. The displacements between the base image set and fused image set were measured. For slices with different z-positions, the displacement of the 8-cm column was assessed. For 20 clinical MRI cases, the distance between the dorsum sellae and the cranial nerves was measured. RESULTS: No significant differences were found between the different FOVs or image sequences. However, with the different matrix sizes and modalities, significant displacements were observed, although they were all within 0.5 mm. Similar displacements were observed in the slices at different z-positions. All cranial nerves were located within 40 mm of the dorsum sellae. CONCLUSIONS: The displacements following image fusion were within approximately 0.5 mm, even at 8 cm from the center. This suggests that the region where the cranial nerves are located, within 40 mm of the dorsum sellae, had no risk of positional error following image fusion.

Repeated intravenous infusion of mesenchymal stem cells for enhanced functional recovery in a rat model of chronic cerebral ischemia.

OBJECTIVE: Stroke is a major cause of long-term disability, and there are few effective treatments that improve function in patients during the chronic phase of stroke. Previous research has shown that single systemic infusion of mesenchymal stem cells (MSCs) improves motor function in acute and chronic cerebral ischemia models in rats. A possible mechanism that could explain such an event includes the enhanced neural connections between cerebral hemispheres that contribute to therapeutic effects. In the present study, repeated infusions (3 times at weekly intervals) of MSCs were administered in a rat model of chronic stroke to determine if multiple dosing facilitated plasticity in neural connections. METHODS: The authors induced middle cerebral artery occlusion (MCAO) in rats and, 8 weeks thereafter, used them as a chronic stroke model. The rats with MCAO were randomized and intravenously infused with vehicle only (vehicle group); with MSCs at week 8 (single administration: MSC-1 group); or with MSCs at weeks 8, 9, and 10 (3 times, repeated administration: MSC-3 group) via femoral veins. Ischemic lesion volume and behavioral performance were examined. Fifteen weeks after induction of MCAO, the thickness of the corpus callosum (CC) was determined using Nissl staining. Immunohistochemical analysis of the CC was performed using anti-neurofilament antibody. Interhemispheric connections through the CC were assessed ex vivo by diffusion tensor imaging. RESULTS: Motor recovery was better in the MSC-3 group than in the MSC-1 group. In each group, there was no change in the ischemic volume before and after infusion. However, both thickness and optical density of neurofilament staining in the CC were greater in the MSC-3 group, followed by the MSC-1 group, and then the vehicle group. The increased thickness and optical density of neurofilament in the CC correlated with motor function at 15 weeks following induction of MCAO. Preserved neural tracts that ran through interhemispheric connections via the CC were also more extensive in the MSC-3 group, followed by the MSC-1 group and then the vehicle group, as observed ex vivo using diffusion tensor imaging. CONCLUSIONS: These results indicate that repeated systemic administration of MSCs over 3 weeks resulted in greater functional improvement as compared to single administration and/or vehicle infusion. In addition, administration of MSCs is associated with promotion of interhemispheric connectivity through the CC in the chronic phase of cerebral infarction.

Pitfalls of Commonly Used Ischemic and Dementia Models Due to Early Seizure by Carotid Ligation.

While the bilateral common carotid artery (CCA) ligation model is widely used in cerebrovascular disease and dementia studies, it can frequently cause seizures. We examined the validity of seizure as an experimental model of ischemia. Eight-week-old male Wistar and Sprague-Dawley (SD) rats were implanted with electrocorticography (ECoG) electrodes and bilateral CCA ligation was performed and compared to the sham groups. ECoG monitoring was used to confirm the seizure discharge and count the number of spikes in the interictal phase 2 h after ligation, followed by power spectral analysis. Magnetic resonance imaging (MRI) was performed 6 h after bilateral CCA ligation to assess fractional anisotropy (FA), apparent diffusion coefficient (ADC), and cerebral blood flow (CBF) values. Magnetic resonance spectroscopy (MRS) was also performed and the ischemic parameters and electrophysiological changes were compared. The Wistar rat group had significantly higher mortality, frequency of seizures, incidence of non-convulsive seizures, and number of spikes in the interictal period compared to those in the SD rat group. Power spectral analysis showed increased power in the delta band in both Wistar and SD rat groups. MRI, after CCA ligation, showed significantly lower ADC values, lower glutamine and glutamate levels, and higher lactate values in Wistar rats, although there was no difference in FA values. Metabolic and electrophysiological changes after CCA ligation differed according to the rat strain. Wistar rats were prone to increased lactate and decreased glutamine and glutamate levels and the development of status epilepticus. Seizures can affect the results of ischemic experiments.

Intravenous Infusion of Mesenchymal Stem Cells Enhances Therapeutic Efficacy of Reperfusion Therapy in Cerebral Ischemia.

OBJECTIVE: Reperfusion therapy is a standard therapeutic strategy for acute stroke. Non-favorable outcomes are thought to partially result from impaired microcirculatory flow in ischemic tissue. Intravenous infusion of mesenchymal stem cells (MSCs) reduces stroke volume and improves behavioral function in stroke. One suggested therapeutic mechanism is the restoration of the microvasculature. The goal of this study was to determine whether infused MSCs enhance the therapeutic efficacy of reperfusion therapy following stroke in rats. METHODS: First, to establish a transient middle cerebral artery occlusion (MCAO) model displaying approximately identical neurologic function and lesion volume as seen in permanent MCAO (pMCAO) at day 7 after stroke induction, we transiently occluded the MCA for 90, 110, and 120 minutes. We found that the 110-minute occlusion met these criteria and was used as the transient MCAO (tMCAO) model. Next, 4 MCAO groups were used to compare the therapeutic efficacy of infused MSCs: (1) pMCAO+vehicle, (2) tMCAO+vehicle, (3) pMCAO+MSC, and (4) tMCAO+MSC. Our ischemic model was a unique ischemic model system in which both pMCAO and tMCAO provided similar outcomes during the study period in the groups without MSC infusion groups. Behavioral performance, ischemic volume, and regional cerebral blood flow (rCBF) using arterial spin labeling-magnetic resonance imaging and histologic evaluation of microvasculature was performed. RESULTS: The behavioral function, rCBF, and restoration of microvasculature were greater in group 4 than in group 3. Thus, infused MSCs facilitated the therapeutic efficacy of MCA reperfusion in this rat model system. CONCLUSIONS: Intravenous infusion of MSCs may enhance therapeutic efficacy of reperfusion therapy.

Optimal acceleration factor for image acquisition in turbo spin echo: diffusion-weighted imaging with compressed sensing.

In this study, the change in the image quality and apparent diffusion coefficient (ADC) with increase in the acceleration factor (AF) was analyzed and the most optimal AF was determined to reduce the scan time while preserving the image quality. The AF was changed from 2 to 20 in the MR acquisitions. The similarities between the accelerated and reference images were determined based on the structural similarity (SSIM) index for DWI image and coefficient of variation (%CV) for ADC. The SSIM index decreased significantly when the AF ≥ 8 compared with when the AF = 2 (p < 0.05). In the reference image, the %CV of the ADC increased significantly when the AF ≥ 10 (p < 0.01). In conclusion, a remarkable decrease in the image quality and ADC was observed when the AF was > 8. Thus, an AF < 8 would be optimal for reducing the scan time while preserving the image quality.

Visualization of cerebellar peduncles using diffusion tensor imaging.

The cerebellum communicates with the cerebral cortex via the superior, middle, and inferior cerebellar peduncles (CPs). To preserve the structure and function of the brainstem and cerebellum, which is compressed in various pathological conditions, it is important to delineate the spatial interrelationship of the CPs for presurgical planning and intraoperative guidance. Diffusion tensor tractography (DTT) is a technique capable of depicting the major fiber bundles in CPs. However, routine use of this technology for brainstem visualization remains challenging due to the anatomical smallness and complexity of the brainstem and susceptibility-induced image distortions. Here, we attempt to visualize CPs using high-resolution DTT in a commercial equipment for the application of this technique in normal clinical settings. DTT and fast imaging employing steady-state acquisition-cycled phases (FIESTA) of the whole brainstem were performed. We rendered the DTT fiber bundle using a region-of-interest-based fiber tracking method onto the structural image generated in FIESTA by automatic image coregistration. Fibers of the CPs were clearly visualized by DTT. The DTT-FIESTA overlaid image revealed the cross-sectional and three-dimensional anatomy of the pyramidal tract and the ascending sensory fibers, in addition to the CPs. This could indicate a geometrical relationship of these fibers in the brainstem. The CPs could be visualized clearly using DTT within clinically acceptable scanning times. This method of visualizing the exact pathway of fiber bundles and cranial nerves in the skull base helps in the planning of surgical approaches.

Arterial transit artifacts observed by arterial spin labeling in Moyamoya disease.

OBJECTIVES: Arterial spin labeling (ASL) is a magnetic resonance imaging (MRI) technique used to assess cerebral perfusion. When tissue perfusion is impaired, such as in Moyamoya disease, a hyperintense band called the arterial transit artifact (ATA) may occur, which interferes with accurate measurements on ASL-MRI. In this study, we evaluated the correlation of ATAs with magnetic resonance angiography (MRA) and single-photon emission computed tomography (SPECT) imaging results in Moyamoya disease. The aim of our study was to elucidate the pathophysiology of ATAs and risk factors for high ATA scores. MATERIALS AND METHODS: This retrospective study included 28 patients (56 hemispheres) with Moyamoya disease treated at our institution. MRI, MRA, ASL perfusion, and N-isopropyl-[123I] b-iodoamphetamine (123I-IMP) SPECT were performed. In order to semi-quantitatively evaluate the degree of ATA, the ATA scores were measured according to the number of hyperintense signal bands in the cerebral cortex. The relationship between the ATA scores and clinical and radiological factors were analyzed. RESULTS: Regional cerebral blood flow (rCBF) determined with ASL weakly correlated with that determined by 123I-IMP SPECT (ρ=0.31, p=0.027). There was no significant association between the ATA scores and rCBF values determined with 123I-IMP SPECT (p=0.872, 0.745, 0.743 at PLD1000 (post-labeling delay), 1500, and 2000, respectively). However, there was a significant correlation between ATA scores and MRA scores (ρ=0.427 p=0.001; ρ=0.612 p=0.001; ρ=0.563 p=0.001 at PLD1000, 1500, and 2000, respectively). An analysis of patient background characteristics revealed a significantly higher incidence of high ATA scores in female patients, patients with high MRA scores, and patients with a distinguishable ivy sign. A multivariate analysis confirmed that female sex, high MRA score, and presence of an ivy sign were risk factors for high ATA scores. CONCLUSION: ATA scores were moderately correlated with MRA scores, and presence of an ivy sign was the most predictive factor for high ATA scores. A high ATA score determined using ASL in a patient with Moyamoya disease might suggest an advanced disease stage and a reduction in cerebrovascular reserve capacity.

Intravenous delivery of mesenchymal stem cells protects both white and gray matter in spinal cord ischemia.

Ischemic spinal cord injury (iSCI) is a devastating complication of aortic surgery, with few strategies for prevention. Intravenous infusion of mesenchymal stem cells (MSCs) for iSCI has been shown to provide functional improvement through protection of gray matter. The purpose of this study was to investigate additional mechanisms which may exert therapeutic efficacy in iSCI. Severe iSCI was created to occlude the descending aorta, which was cross-clamped 5 mm distal to the left subclavian artery for 16 min. One day after iSCI induction, iSCI rats were randomized into two groups: one received intravenous infusion of MSCs (MSC-group), the other received vehicle (no cells; vehicle-group). Locomotor function and in vivo MRI were recorded. H&E, Nissl and toluidine blue stainings, immunohistochemical analysis, diffusion tensor imaging (DTI), and the assessment of blood-spinal cord barrier (BSCB) stability were performed. MSC treated animals exhibited gradual improvement in hind-limb locomotor function during the 4-week study period; however the vehicle-treated group displayed persistent motor deficits. In the MSC-treated group we observed the protection of white and gray matter volume reduction of axonal and neuronal loss or degeneration and preservation of microvasculature including BSCB function. Intravenous infusion of MSCs may provide therapeutic efficacy to improve functional outcomes in a rat model of severe iSCI via protection of white and gray matter.

Prolonged lifespan in a spontaneously hypertensive rat (stroke prone) model following intravenous infusion of mesenchymal stem cells.

Intravenous infusion of mesenchymal stem cells (MSCs) has been reported to provide therapeutic efficacy via microvascular remodeling in a spontaneously hypertensive rat. In this study, we demonstrate that intravenous infusion of MSCs increased the survival rate in a spontaneously hypertensive (stroke prone) rat model in which organs including kidney, brain, heart and liver are damaged during aging due to spontaneous hypertension. Gene expression analysis indicated that infused MSCs activates transforming growth factor-ß1-smad3/forkhead box O1 signaling pathway. Renal dysfunction was recovered after MSC infusion. Collectively, intravenous infusion of MSC may extend lifespan in this model system.

Intravenous infusion of mesenchymal stem cells improves impaired cognitive function in a cerebral small vessel disease model.

Cerebral small vessel disease (CSVD) is not only a cause of vascular dementia (VD) but also a contributing factor to Alzheimer's disease (AD). The essential pathological feature of CSVD is the disruption of blood-brain barrier (BBB). Dysfunction of BBB due to degeneration of both endothelial cells and pericytes in capillaries leads to neuronal damage and progressive brain atrophy. Moreover, deterioration of amyloid-ß (Aß) clearance due to the failure of the transvascular BBB transport system results in accumulation of Aß in the brain. Intravenous infusion of mesenchymal stem cells (MSCs) elicits functional recovery in experimental models including stroke and spinal cord injury. One effect of MSCs is to restore disrupted BBB through remodeling of microvasculature. Using spontaneously hypertensive rats (stroke-prone) with impaired cognitive function as a CSVD model, we have shown that infused MSCs has a therapeutic effect for cognitive function. Restoration of BBB function via remodeling of microvasculature and inhibition of Aß accumulation could inhibit progressive brain atrophy and lead to restore cognitive dysfunction. Gene expression analysis indicated that infused MSCs activates both transforming growth factor-ß and angiopoietin 1 signaling pathways and promotes the remodeling of microvasculature. Thus, infused MSCs may represent a novel therapy for both VD and AD.

Elevated brain derived neurotrophic factor levels in plasma reflect in vivo functional viability of infused mesenchymal stem cells for stroke in rats.

BACKGROUND: Intravenous infusion of mesenchymal stem cells (MSCs) derived from adult bone marrow elicits functional recovery in rat stroke models and clinical studies in patients are ongoing. Brain derived neurotrophic factor (BDNF) is a neurotrophic factor produced by MSCs and may contribute to their therapeutic efficacy. The purpose of the current study was to determine if BDNF is elevated in infarcted brain and in which compartment of blood (plasma or serum) after intravenous MSC infusion in a middle cerebral artery occlusion (MCAO) model in the rat. METHODS: In rats, a permanent middle cerebral artery occlusion (MCAO) was induced by intraluminal vascular occlusion with a microfilament and MSCs were intravenously administered 6 h after right MCAO induction. Enzyme-linked immunosorbent assay (ELISA) analysis of brain, serum and plasma BDNF were performed after the MSC infusion following the MCAO induction. Lesion volume was assessed using magnetic resonance imaging. Functional outcome was assessed using the Limb Placement Test. RESULTS: Infused MSCs reduced lesion volume and elicited functional improvement compared to the vehicle infused group. ELISA analysis of the MSC treated group revealed an increase BDNF levels in the infarcted hemisphere of the brain and plasma, but not in serum. The MSC group showed a greater increase in BDNF levels than sham control. In the MSC group, the expression of increased plasma BDNF levels correlated with increased brain BDNF levels. CONCLUSIONS: These results support the hypothesis that BDNF levels in plasma, but not serum, may be more appropriate to detect circulating BDNF in vivo following MSC infusion in a cerebral infarction rat model of ischemic stroke. Further, plasma BDNF might reflect in vivo functional viability of infused MSCs after stroke.