Xiangtong Zhang

Hematoma Volume Affects the Accuracy of Computed Tomographic Angiography ‘Spot Sign’ in Predicting Hematoma Expansion after Acute Intracerebral Hemorrhage

Background: We hypothesized that the presence of tiny, enhancing foci (‘spot sign’) within acute hematomas is associated with hematoma expansion. Methods: We retrospectively analyzed the effect of hematoma volume on accuracy of computed tomographic angiography (CTA) in predicting hematoma expansion in 312 patients with acute intracerebral hemorrhage (ICH). The patients were divided into 2 groups according to their initial hematoma volume (<30 vs. ≧30 ml). CTA was performed at admission and 24 h after initial presentation. Results: The <30-ml group consisted of 203 patients of whom 42 had hematoma expansion (20.9%). The ≧30-ml group consisted of 109 patients of whom 34 had hematoma expansion (31.19%). In the <30-ml group, the sensitivity and specificity of CTA in predicting hematoma expansion were 71.4 and 93.8%, respectively. In the ≧30-ml group, the sensitivity and specificity of CTA were 85.7 and 91.9%, respectively. For all 312 patients, the area under the curve was 0.86 (p < 0.001, 95% CI 0.80–0.92); the sensitivity and specificity of CTA were 77.9 and 93.2%, respectively. Conclusions: CTA can reliably predict hematoma expansion in clinical practice, especially for hematomas >30 ml.

Transplantation of Bone Marrow Stromal Cells Enhances Nerve Regeneration of the Corticospinal Tract and Improves Recovery of Neurological Functions in a Collagenase-Induced Rat Model of Intracerebral Hemorrhage

The reorganization of brain structures after intracerebral hemorrhage (ICH) insult is crucial to functional outcome. Although the pattern of neuronal rewiring is well-documented after ischemic stroke, the study of brain plasticity after ICH has been focusing on the enhancement of dendritic complexity. Here we hypothesized that functional restoration after ICH involves brain reorganization which may be favorably modulated by stem cell transplantation. In this study, bone marrow stromal cells (BMSCs) were transplanted into the perilesional sites of collagenaseinduced ICH in adult rats one day after ICH injury. Forelimb functional recovery was monitored with modified limb placing and vibrissae-elicited forelimb placement tests. Anterograde and retrograde tracing were used to assess the reorganization of bilateral forelimb areas of the sensorimotor cortex. We found that in rats transplanted with BMSCs after ICH injury, axonal sprouting occurred in the contralateral caudal forelimb area of the cortex, and was significantly higher than in ICH rat models that received only the vehicle (P < 0.01). The number of positive neurons in the ipsilateral rostral forelimb area of the cortex of the BMSC group was 1.5-to 4.5-fold greater than in the vehicle group (P < 0.05). No difference was found between the BMSC and vehicle groups in hemispheric atrophy or labeled neurons in the ipsilateral caudal forelimb area (P = 0.193). Scores for improved functional behavior in the BMSC group were in accord with the results from histology. Neuronal plasticity of the denervated corticospinal tract at bilateral forelimb areas of the cortex in the collagenase-induced ICH rat models was significantly enhanced by BMSC transplantation. BMSC transplantation may facilitate functional recovery after ICH injury.

The effect of simvastatin treatment on proliferation and differentiation of neural stem cells after traumatic brain injury.

OBJECTIVE To study the effect of simvastatin on neurological functional recovery after traumatic brain injuries (TBI) and the possible molecular mechanisms, we evaluated simvastatin-induced proliferation and differentiation of neural stem cells (NSCs) in vitro and in vivo and possible involvement of Notch-1 signaling in this process. METHODS Adult Wistar rats were randomly divided into three groups (n=28 for each): sham group, saline-treated group and simvastatin-treated group. Simvastatin was given orally at a dose of 1mg/kg/day starting at day 1 after TBI. At 1, 3, 7, 14, 21, 28, and 35 days after simvastatin treatment, functional outcome was measured using modified neurological severity scores (mNSS). Immunofluorescence of nestin was used to identify neurogenesis of NSCs in injured area of TBI rats. Western blot was applied to detect the expression level of Notch-1 protein in TBI rats with simvastatin. RESULTS Immunostaining showed a significant increase in the number of nestin-positive cells in injured area of the simvastatin-treated group compared to that of the saline-treated group (p<0.05). In in vitro experiment, simvastatin induced enhanced proliferation and neurogenesis of cultured NSCs and elevated Notch-1 protein expression. Co-incubation of γ-secretase inhibitor, an inhibitor of Notch-1 pathway, with simvastatin abolished its neurorestoration effect. Most importantly, the simvastatin-treated group had significantly decreased mNSS at day 35 after TBI compared with the saline-treated group (p<0.05). CONCLUSION Simvastatin treatment enhanced neurological functional recovery after TBI possibly via activation of Notch signaling and increasing neurogenesis in the injured area.

OPN gene polymorphism and the serum OPN levels confer the susceptibility and prognosis of ischemic stroke in Chinese patients.

Aim: To investigate the association of Osteopontin (OPN) gene polymorphism and serum thrombin-cleaved OPN level with the susceptibility to ischemic stroke (IS) and its prognosis. Methods: A total of 377 patients with IS and 551 healthy individuals were recruited. The OPN gene polymorphisms at -156 G>GG, -443 C>T and -66 T>G were genotyped. Serum full-length and the thrombin-cleaved OPN were determined. Results: We found that only the -443 C>T polymorphism was significantly associated with the susceptibility to IS. The -443 CC represented a near 2 time higher risk for IS incidence than TT carriers. Also, the -443 CC genotype had significantly poorer outcome and they significantly had higher occurrence for bad recovery as determined by modified Rankin Scale (mRS) (OR=2.18, p=0.043) and Barthel Index (BI) (OR=2.12, p=0.05). The mean serum thrombin-cleaved OPN level in IS group were significantly higher than that in control group. ROC analysis showed that the thrombin-cleaved OPN level (cut-off value, 166.8 ng/ml) can discriminate IS patients from controls with a specificity of 86.3% and a sensitivity of 57.7%. The serum thrombin-cleaved OPN was significantly associated with the clinical outcome at 12 months after discharge from hospital. Conclusion: These results suggest that the -443 C>T polymorphism of OPN gene and serum thrombin-cleaved OPN can be used as a biomarker for the susceptibility and prognosis of IS patients.

Reversal effects of two new milbemycin compounds on multidrug resistance in MCF-7/adr cells in vitro.

Development of agents to overcome multidrug resistance (MDR) is important in cancer chemotherapy, and the overexpression of P-glycoprotein (P-gp) is one of the major mechanisms of MDR. In this paper, we evaluated the effects of two new milbemycin compounds, milbemycin β(14) and secomilbemycin D, isolated from fermentation broth of S. bingchenggensis on reversing MDR of adriamycin-resistant human breast carcinoma (MCF-7/adr) cells. We observed that the both milbemycins (5 μM) showed strong potency to increase adriamycin cytotoxicity toward MCF-7/adr cells with reversal fold (RF) of 13.5 and 10.59, respectively. In addition, the mechanisms of milbemycins on reversing P-gp-mediated MDR demonstrated that they significantly increased the accumulations of adriamycin and Rh123 via inhibiting P-gp efflux in MCF-7/adr cells. Furthermore, the results also revealed that milbemycin β(14) and secomilbemycin D could regulate down the expression of P-gp, but not affect the expression of MDR1 gene. In conclusion, our observations suggest that the two new milbemycin compounds probably represent the promising agents for reversing MDR in cancer therapy.

TUSC3 suppresses glioblastoma development by inhibiting Akt signaling

Glioblastoma multiform is one of the most common and most aggressive brain tumors in humans. The molecular and cellular mechanisms responsible for the onset and progression of GBM are elusive and controversial. The function of tumor suppressor candidate 3 (TUSC3) has not been previously characterized in GBM. TUSC3 was originally identified as part of an enzyme complex involved in N-glycosylation of proteins, but was recently implicated as a potential tumor suppressor gene in a variety of cancer types. In this study, we demonstrated that the expression levels of TUSC3 were downregulated in both GBM tissues and cells, and also found that overexpression of TUSC3 inhibits GBM cell proliferation and invasion. In addition, the effects of increased levels of methylation on the TUSC3 promoter were responsible for decreased expression of TUSC3 in GBM. Finally, we determined that TUSC3 regulates proliferation and invasion of GBM cells by inhibiting the activity of the Akt signaling pathway.

Human amniotic epithelial stem cells inhibit microglia activation through downregulation of tumor necrosis factor-α, interleukin-1β and matrix metalloproteinase-12 in vitro and in a rat model of intracerebral hemorrhage

BACKGROUND AIMS The molecular mechanisms by which stem cell transplantation improves functional recovery after intracerebral hemorrhage (ICH) are not well understood. Accumulating evidence suggests that microglia cells are activated shortly after ICH and that this activation contributes to secondary ICH-induced brain injury. We studied the effect of human amniotic epithelial stem cells (HAESCs) on microglia activation. METHODS To study the effect of HAESCs in vitro, we used thrombin to activate the microglia cells. Twenty-four hours after thrombin treatment, the levels of tumor necrosis factor-α and interleukin-1β were measured by enzyme-linked immunosorbent assay. In vivo, the HAESCs were transplanted into the rat striatum 1 day after collagenase-induced ICH. The expression levels of matrix metalloproteinase (MMP)-12 and microglia infiltration in the peri-hematoma tissues were determined 7 days after ICH through the use of reverse transcriptase-polymerase chain reaction and immunohistochemical analysis, respectively. RESULTS Thrombin-activated microglia expression of tumor necrosis factor-α, interleukin-1β and MMP-12 was significantly reduced through contact-dependent and paracrine mechanisms when the HAESCs were co-cultured with microglia cells. After transplantation of HAESCs in rat brains, the expression levels of MMP-12 and microglia infiltration in the peri-hematoma tissues were significantly reduced. CONCLUSIONS Our observations suggest that microglia activation could be inhibited by HAESCs both in vitro and in vivo, which may be an important mechanism by which the transplantation of HAESCs reduces brain edema and ameliorates the neurologic deficits after ICH. Therefore, we hypothesize that methods for suppressing the activation of microglia and reducing the inflammatory response can be used for designing effective treatment strategies for ICH.

Spinal duraplasty with two novel substitutes restored locomotor function after acute laceration spinal cord injury in rats

A dural tear is a common complication after acute laceration spinal cord injury (ALSCI). An unrepaired dural tear is associated with poor locomotor functional recovery. Spinal duraplasty with biomaterials may promote functional recovery in ALSCI. However, an ideal dural substitute has not yet been found. In this work, we investigated the possibility of using a denuded human amniotic membrane (DHAM) or DHAM seeded on bone marrow stromal cells (DHAM-BMSCs) as duraplasty biomaterials. We patched broken dura with the two novel substitutes in an ALSCI rat model. At the end of the eighth week, we observed that the neural motor function was recovered according to the Basso-Beattie-Bresnahan scale, and the neural loop was successfully reestablished between the ends of the lesions by motor-evoked potentials in the duraplasty groups. Moreover, the DHAM-BMSCs repaired the dura and resulted in a significant reduction in the total lesion and cystic volumes by nearly 10-fold versus the control group (p < 0.01). The levels of neurotrophic factors and NF-200-positive fibers were also improved in the duraplasty groups, compared to the control group. Our data suggest that the two novel substitutes may be promising grafts for patching dural defects to improve locomotor function after ALSCI.

Multifunctional upconversion nanoparticles for targeted dual-modal imaging in rat glioma xenograft

Purpose Achieving a radiographic gross total resection in high-grade gliomas improves overall survival. Many technologies such as intraoperative microscope, intraoperative ultrasound, fluorescence imaging, and intraoperative magnetic resonance imaging have been applied to improve tumor resection. However, most commercial available magnetic resonance imaging contrast agents have limited permeability across the blood–brain barrier and are cleared rapidly from circulation. Fluorescence imaging discriminates tumor from normal tissue and provides a promising new strategy to maximize sage surgical resection of tumor. However, the penetration depth of fluorescence imaging is generally low. Materials and methods In this study, a new type of magnetite NaGdF4:Yb3+,Er3+,Li+@NaGdF4 (UCNPs) core-shell nanoparticles, coated with SiO2 and further functionalized with glioma and blood–brain barrier targeting motifs, was prepared for dual-modal in vivo upconversion imaging and magnetic resonance imaging. Results The as-prepared multifunctional upconversion nanoparticles (UCNPs@SiO2-CX-Lf) were biocompatible, showed strong upconversion luminescence under excitation of 980 nm, and provided high signal-to-noise ratio in vivo. Moreover, UCNPs@SiO2-CX-Lf nanoparticles showed a high relaxivity of 1.25 S-1 mM-1 and were successfully applied as contrast agent for magnetic resonance imaging in tumor xenograft rat model with prolonged tumor signal enhancement. In vivo and magnetic resonance imaging Upconversion Luminescence (UCL) imaging results indicated that these particles can across the blood–brain barrier, bind to glioma, gave bright UCL signal and T1 magnetic resonance imaging contrast. Conclusions Targeted UCL and magnetic resonance imaging dual-modal in vivo imaging using Yb3+/Er3+/Li+ codoped NaGdF4 core-shell nanostructure can serve as a platform technology for the next generation of intraoperative probes for image-guided tumor resection.

Moxidectin inhibits glioma cell viability by inducing G0/G1 cell cycle arrest and apoptosis

Moxidectin (MOX), a broad-spectrum antiparasitic agent, belongs to the milbemycin family and is similar to avermectins in terms of its chemical structure. Previous research has revealed that milbemycins, including MOX, may potentially function as effective multidrug resistance agents. In the present study, the impact of MOX on the viability of glioma cells was examined by MTT and colony formation assay, and the molecular mechanisms underlying MOX-mediated glioma cell apoptosis were explored by using flow cytometry and apoptosis rates. The results demonstrated that MOX exerts an inhibitory effect on glioma cell viability and colony formations in vitro and xenograft growth in vivo and is not active against normal cells. Additionally, as shown by western blot assay, it was demonstrated that MOX arrests the cell cycle at the G0/G1 phase by downregulating the expression levels of cyclin-dependent kinase (CDK)2, CDK4, CDK6, cyclin D1 and cyclin E. Furthermore, it was revealed that MOX is able to induce cell apoptosis by increasing the Bcl-2-associated × protein/B-cell lymphoma 2 ratio and activating the caspase-3/-9 cascade. In conclusion, these results suggest that MOX may inhibit the viability of glioma cells by inducing cell apoptosis and cell cycle arrest, and may be able to function as a potent and promising agent in the treatment of glioma.