Cerebral pericytes are perivascular cells that stabilize blood vessels. Little is known about the plasticity of pericytes in the adult brain in vivo. Recently, using state-of-the-art technologies, including two-photon microscopy in combination with sophisticated Cre/loxP in vivo tracing techniques, a novel role of pericytes was revealed in vascular remodeling in the adult brain. Strikingly, after pericyte ablation, neighboring pericytes expand their processes and prevent vascular dilatation. This new knowledge provides insights into pericyte plasticity in the adult brain.
Animals ; Brain ; blood supply ; physiology ; physiopathology ; Brain Diseases ; physiopathology ; Capillaries ; physiology ; Cellular Microenvironment ; Diabetic Retinopathy ; physiopathology ; Endothelial Cells ; physiology ; Humans ; Pericytes ; physiology ; Vascular Remodeling

The purpose of this study was to establish a method to record the dynamic process of vascular regeneration and remodeling in rat cerebral ischemic regions. An animal brain window model was established to continuously observe the changes of rat cortical vascular ischemia in vivo, and the model of cerebral ischemia was established by photochemical embolization. Optical coherence tomography (OCT) was performed to record the formation of vascular blockage and the injury and regeneration of small vessels during cerebral ischemia recovery. The results showed that 30 min of laser irradiation could completely block the cortical vessels in rats. Within 24-48 h after ischemia, the degree of brain injury was the greatest, and the number of blood vessels in the ischemic region reached the minimum. Then the blocked blood vessels began to be dredged, and the small blood vessels around the ischemic area began to regenerate. Small blood vessels in the superficial/deep layers of the cortex disappeared significantly after laser irradiation. During 10 d after ischemia, the blocked blood vessels were gradually dredged and recovered. On the 10th day after laser irradiation, a large number of neovascularization appeared in the superficial layer of cortex, but the deep vessels did not recover. These results indicate that the method established in this study can observe the changes of blood vessel in cerebral ischemic region continuously, which lays a foundation for further quantitative study on the dynamics of embolized blood vessels and peripheral capillaries during the recovery of cerebral ischemia.
Animals ; Brain ; blood supply ; Brain Ischemia ; Cerebral Cortex ; blood supply ; Rats ; Regeneration

Brain ; blood supply ; pathology ; surgery ; Diagnosis, Differential ; Humans ; Middle Aged ; Pituitary Neoplasms ; cerebrospinal fluid ; complications ; diagnosis ; Stroke ; cerebrospinal fluid ; complications ; diagnosis ; Tuberculosis ; cerebrospinal fluid ; complications ; diagnosis

Objective Oxidative stress (OS) plays a crucial role in ischemic stroke. Grape seed procyanidin extract (GSPE) was reported to be a critical regulator of OS. We hypothesized that GSPE might also be protective in ischemia-reperfusion brain injury. This study aimed to explore whether GSPE administration can protect mice from ischemia-reperfusion brain injury.Methods Transient middle cerebral artery occlusion (MCAO) was conducted followed by reperfusion for 24 hours to make ischemia-reperfusion brain injury in mice that received GSPE (MCAOG, n=60) or normal saline (MCAONS, n=60). Sham-operated mice (GSPE group and normal saline group) were set as controls. The neurological severity score (NSS) was used to evaluate neural function impairment 1 hour, 24 hour, 3 days and 7 days after MCAO. Mice underwent brain T2WI imaging with a 3T animal MRI scanner 24 hours after reperfusion, and the stroke volume of brains were calculated according to abnormal signal intensity. Immunohistopathological analysis of brain tissues at 24 h after reperfusion was performed for neuronal nuclear antigen (NeuN), CD34, Bcl-2, and Bax. Glutathione peroxidation (GSH-Px) activity and the level of malonaldehyde (MDA) of brain tissue were also examined. The above indexes were compared among the groups statistically.Results Significant functional improvement was observed 24 hours after MCAO in MCAOG group compared to MCAONS group (P<0.05). MCAOG group had smaller cerebral stroke volume (22.46 ± 11.45 mmvs. 47.84±9.06 mm, P<0.05) than MCAONS group 24 hours after MCAO. More mature NeuN-immunoreactive neurons and more CD34-positive cells in peri-infarct zones were observed in brain tissue of MCAOG mice 24 h after MCAO than that of MCAONS mice (both P<0.05). MCAONS mice had significantly higher number of Bax-positive cells in brain tissue than MCAOG (P<0.05). The mean MDA level was significantly lower (P<0.05) and the GSH-Px activity was significantly higher (P<0.05) in brains of MCAOG mice compared to those of MCAONS mice.Conclusion GSPE administration protects mice from ischemia-reperfusion brain injury through attenuating oxidative stress and apoptosis, promoting angiogenesis, and activating antioxidant enzyme GSH-Px. GSPE may represent a new therapeutical direction for the treatment of ischemia-reperfusion brain injury.
Animals ; Apoptosis ; drug effects ; Brain ; blood supply ; Glutathione Peroxidase ; metabolism ; Grape Seed Extract ; pharmacology ; Infarction, Middle Cerebral Artery ; Male ; Mice ; Mice, Inbred C57BL ; Neuroprotective Agents ; pharmacology ; Oxidative Stress ; Proanthocyanidins ; pharmacology ; Reperfusion Injury ; drug therapy ; metabolism

Although 5-aminolevulinic acid (5-ALA)-mediated photodynamic therapy (PDT) has been demonstrated to be a novel and effective therapeutic modality for some human malignancies, its effect and mechanism on glioma are still controversial. Previous studies have reported that 5-ALA-PDT induced necrosis of C6 rat glioma cells in vitro. The aim of this study was to further investigate the effect and mechanism of 5-ALA-PDT on C6 gliomas implanted in rats in vivo. Twenty-four rats bearing similar size of subcutaneously implanted C6 rat glioma were randomly divided into 3 groups: receiving 5-ALA-PDT (group A), laser irradiation (group B), and mock procedures but without any treatment (group C), respectively. The growth, histology, microvessel density (MVD), and apoptosis of the grafts in each group were determined after the treatments. As compared with groups B and C, the volume of tumor grafts was significantly reduced (P<0.05), MVD was significantly decreased (P<0.001), and the cellular necrosis was obviously increased in group A. There was no significant difference in apoptosis among the three groups. The in vivo studies confirmed that 5-ALA-PDT may be an effective treatment for gliomas by inhibiting the tumor growth. The mechanism underlying may involve increasing the cellular necrosis but not inducing the cellular apoptosis, which may result from the destruction of the tumor microvessels.
Aminolevulinic Acid ; pharmacology ; therapeutic use ; Animals ; Brain Neoplasms ; blood supply ; drug therapy ; pathology ; Cell Line, Tumor ; Glioma ; blood supply ; drug therapy ; pathology ; Microvessels ; drug effects ; Photochemotherapy ; Photosensitizing Agents ; pharmacology ; therapeutic use ; Rats ; Rats, Wistar ; Xenograft Model Antitumor Assays

OBJECTIVETo observe the three-dimensional distribution of vessels, and to establish a new method for measurement of blood flow velocity in mice cerebral cortex using two-photon laser scanning microscopy and fluorescence probe labeling technique.

METHODSThe mouse was made cranial window surgery and injected Texas-Red through tail vein after anesthetized. The three-dimensional imaging of vessel was obtained through z-stack scanning, and blood flow velocity was quantified through line scanning.

RESULTSWe could detect vascular distribution for more than 500 µm depth using two-photon microscopy. The velocity of blood flow was (0.59 ± 0.12) mm/s in capillary.

CONCLUSIONThe method for observing the brain blood flow by two-photon microscopy was established, which could achieve quantification of single vascular blood flow velocity and provide experimental evidence for basic research and medical applications.

Animals ; Blood Flow Velocity ; Brain ; blood supply ; Capillaries ; Cerebrovascular Circulation ; Fluorescent Dyes ; Hemodynamics ; Mice ; Microscopy, Fluorescence

OBJECTIVETo investigate the effect of occlusal reconstruction on blood flow velocity and cerebral oxygen saturation in patients with malocclusion.

METHODSThirty-three patients with malocclusion treated with occlusal reconstruction in Department of Stomatology, Medical School of Huzhou Normal College from Feb 2011 to Oct 2013 were enrolled in the study. The systolic peak flow velocity (vs), end-diastolic peak flow (vd) , mean peak flow velocity (vm) of middle cerebral artery and the oxygen saturation (rScO2) in the brain were detected at rest or chewing status by using transcranial Doppler color ultrasonography and near-infrared spectroscopy, respectively.

RESULTSIn rest state, vm was significantly increased on 3 months after treatment, while vs and vd were significantly increased on 6 months after treatment and rScO2 were increased on 12 months after treatment (P<0.05). In chewing state, vs, vm, and rScO2 were increased on 3 months after treatment, and vd was increased on 6 months after treatment (P<0.05).

CONCLUSIONOcclusal reconstruction can increase blood flow velocity of middle cerebral artery and cerebral oxygen saturation and improve oxygen supply of the brain in patients with malocclusion.

Blood Flow Velocity ; Brain ; blood supply ; physiology ; Cerebrovascular Circulation ; Humans ; Malocclusion ; surgery ; Oxygen ; physiology ; Reconstructive Surgical Procedures ; Ultrasonography, Doppler, Transcranial

OBJECTIVETo observe the effect of carbon dioxide pneumoperitoneum and Trendelenburg position on cerebral blood backflow during robot-assisted radical prostatectomy in elderly patients.

METHODSFifty elderly patients (65-80 years) and 50 middle-aged patients (45-64 years) undergoing elective robot-assisted prostatectomy were enrolled in this study. For all the patients, jugular bulb and arterial blood gas was monitored and recorded before pneumoperitoneum (0), 10 min after pneumoperitoneum was achieved (T₁), 10 min (T₂) and 60 min (3) after Trendelenberg position, and 10 min in supine position after termination of pneumoperitoneum (4).

RESULTSCompared with those at 0, the mean arterial pressure, heart rate, and BIS value at 1, 2, 3 and 4 all showed no significant variations (P>0.05), but rSO2, SjvO2, and JBP increased significantly in both groups (P<0.01). Compared with those in the middle-aged group, rSO₂, SjvO₂, and JBP increased significantly and Da-jO₂decreased at 2, 3 in the elderly group (P<0.01), but jugular vein blood glucose or lactic acid content showed no significant difference between the two groups (P>0.05).

CONCLUSIONPneumoperitoneum and Trendelenburg position cause more obvious cerebral blood backflow in elderly patients than in middle-aged patients but do not affect cerebral metabolism of oxygen.

Aged ; Aged, 80 and over ; Brain ; blood supply ; Carbon Dioxide ; Head-Down Tilt ; Heart Rate ; Humans ; Jugular Veins ; Male ; Middle Aged ; Monitoring, Physiologic ; Oxygen ; Pneumoperitoneum, Artificial ; Prostate ; surgery ; Prostatectomy ; methods ; Robotic Surgical Procedures ; methods

PURPOSE: We evaluated hemodynamic significance of stenosis on magnetic resonance angiography (MRA) using acetazolamide perfusion single photon emission computed tomography (SPECT). MATERIALS AND METHODS: Of 171 patients, stenosis in internal carotid artery (ICA) and middle cerebral artery (MCA) (ICA-MCA) on MRA and cerebrovascular reserve (CVR) of MCA territory on SPECT was measured using quantification and a 3-grade system. Stenosis and CVR grades were compared with each other, and their prognostic value for subsequent stroke was evaluated. RESULTS: Of 342 ICA-MCA, 151 (44%) presented stenosis on MRA; grade 1 in 69 (20%) and grade 2 in 82 (24%) cases. Decreased CVR was observed in 9% of grade 0 stenosis, 25% of grade 1, and 35% of grade 2. The average CVR of grade 0 was significantly different from grade 1 (p<0.001) and grade 2 stenosis (p=0.007). In quantitative analysis, average CVR index was -0.56+/-7.91 in grade 0, -1.81+/-6.66 in grade 1 and -1.18+/-5.88 in grade 2 stenosis. Agreement between stenosis and CVR grades was fair in patients with lateralizing and non-lateralizing symptoms (kappa=0.230 and 0.346). Of the factors tested, both MRA and CVR were not significant prognostic factors (p=0.104 and 0.988, respectively), whereas hypertension and renal disease were significant factors (p<0.05, respectively). CONCLUSION: A considerable proportion of ICA-MCA stenosis detected on MRA does not cause CVR impairment despite a fair correlation between them. Thus, hemodynamic state needs to be assessed for evaluating significance of stenosis, particularly in asymptomatic patients.
*Acetazolamide ; Adult ; Aged ; Aged, 80 and over ; Brain/blood supply/radionuclide imaging ; Carotid Artery, Internal/physiopathology/radionuclide imaging ; Carotid Stenosis/physiopathology/*radionuclide imaging ; *Cerebrovascular Circulation ; Constriction, Pathologic ; Diuretics ; Female ; *Hemodynamics ; Humans ; Hypertension/physiopathology ; Iodine Radioisotopes ; *Magnetic Resonance Angiography ; Male ; Middle Aged ; *Radiopharmaceuticals ; Tomography, Emission-Computed, Single-Photon/*methods

Advances in imaging-based management of acute ischemic stroke now provide crucial information such as infarct core, ischemic penumbra/degree of collaterals, vessel occlusion, and thrombus that helps in the selection of the best candidates for reperfusion therapy. It also predicts thrombolytic efficacy and benefit or potential hazards from therapy. Thus, radiologists should be familiar with various imaging studies for patients with acute ischemic stroke and the applicability to clinical trials. This helps radiologists to obtain optimal rapid imaging as well as its accurate interpretation. This review is focused on imaging studies for acute ischemic stroke, including their roles in recent clinical trials and some guidelines to optimal interpretation.
Brain/blood supply/radiography ; Brain Infarction/*radiography/*therapy ; Cerebral Angiography/methods ; Diagnostic Imaging ; Diffusion Magnetic Resonance Imaging/*methods ; Fibrinolytic Agents/*therapeutic use ; Humans ; Intracranial Hemorrhages/diagnosis/radiography