Liangfu Zhou

Clinical evaluation and follow-up outcome of diffusion tensor imaging-based functional neuronavigation: a prospective, controlled study in patients with gliomas involving pyramidal tracts.

OBJECTIVETo evaluate diffusion tensor imaging (DTI)-based functional neuronavigation in surgery of cerebral gliomas with pyramidal tract (PT) involvement with respect to both perioperative assessment and follow-up outcome. METHODSA prospective, randomized controlled study was conducted between 2001 and 2005. A consecutive series of 238 eligible patients with initial imaging diagnosis of cerebral gliomas involving PTs were randomized into study (n = 118) and control (n = 120) groups. The study cases underwent DTI and three-dimensional magnetic resonance imaging scans. The maps of fractional anisotropy were calculated for PT mapping. Both three-dimensional magnetic resonance imaging data sets and fractional anisotropy maps were integrated by rigid registration, after which the tumor and adjacent PT were segmented and reconstructed for presurgical planning and intraoperative guidance. The control cases were operated on using routine neuronavigation. RESULTSThere was a trend for high-grade gliomas (HGGs) in the study group to be more likely to achieve gross total resection (74.4 versus 33.3%, P < 0.001). There was no significant difference of low-grade gliomas resection between the two groups. Postoperative motor deterioration occurred in 32.8% of control cases, whereas it occurred in only 15.3% of the study cases (P < 0.001). The 6-month Karnofsky Performance Scale score of study cases was significantly higher than that of control cases (86 ± 20 versus 74 ± 28 overall, P < 0.001; 93 ± 10 versus 86 ± 17 for low-grade gliomas, P = 0.013; and 77 ± 27 versus 53 ± 32 for HGGs, P = 0.001). For 81 HGGs, the median survival of study cases was 21.2 months (95% confidence interval, 14.1–28.3 mo) compared with 14.0 months (95% confidence interval, 10.2–17.8 mo) of control cases (P = 0.048). The estimated hazard ratio for the effect of DTI-based functional neuronavigation was 0.570, representing a 43.0% reduction in the risk of death. CONCLUSIONDTI-based functional neuronavigation contributes to maximal safe resection of cerebral gliomas with PT involvement, thereby decreasing postoperative motor deficits for both HGGs and low-grade gliomas while increasing high-quality survival for HGGs.

In vivo tracking of superparamagnetic iron oxide nanoparticle-labeled mesenchymal stem cell tropism to malignant gliomas using magnetic resonance imaging : Laboratory investigation

OBJECT Mesenchymal stem cells (MSCs) have been shown to migrate toward tumors, but their distribution pattern in gliomas has not been completely portrayed. The primary purpose of the study was to assay the tropism capacity of MSCs to gliomas, to delineate the pattern of MSC distribution in gliomas after systemic injection, and to track the migration and incorporation of magnetically labeled MSCs using 1.5-T magnetic resonance (MR) imaging. METHODS The MSCs from Fischer 344 rats were colabeled with superparamagnetic iron oxide nanoparticles (SPIO) and enhanced green fluorescent protein (EGFP). The tropism capacity of MSCs was quantitatively assayed in vitro using the Transwell system. To track the migration of MSCs in vivo, MR imaging was performed both 7 and 14 days after systemic administration of labeled MSCs. After MR imaging, the distribution patterns of MSCs in rats with gliomas were examined using Prussian blue and fluorescence staining. RESULTS The in vitro study showed that MSCs possessed significantly greater migratory capacity than fibroblast cells (p<0.001) and that lysis of F98 glioma cells and cultured F98 cells showed a greater capacity to induce migration of cells than other stimuli (p<0.05). Seven days after MSC transplantation, the SPIO-EGFP colabeled cells were distributed throughout the tumor, where a well-defined dark hypointense region was represented on gradient echo sequences. After 14 days, most of the colabeled MSCs were found at the border between the tumor and normal parenchyma, which was represented on gradient echo sequences as diluted amorphous dark areas at the edge of the tumors. CONCLUSIONS This study demonstrated that systemically transplanted MSCs migrate toward gliomas with high specificity in a temporal-spatial pattern, which can be tracked using MR imaging.

Recurrent gain-of-function USP8 mutations in Cushing's disease

Cushings disease, also known as adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas (PAs) that cause excess cortisol production, accounts for up to 85% of corticotrophin-dependent Cushings syndrome cases. However, the genetic alterations in this disease are unclear. Here, we performed whole-exome sequencing of DNA derived from 12 ACTH-secreting PAs and matched blood samples, which revealed three types of somatic mutations in a candidate gene, USP8 (encoding ubiquitin-specific protease 8), exclusively in exon 14 in 8 of 12 ACTH-secreting PAs. We further evaluated somatic USP8 mutations in additional 258 PAs by Sanger sequencing. Targeted sequencing further identified a total of 17 types of USP8 variants in 67 of 108 ACTH-secreting PAs (62.04%). However, none of these mutations was detected in other types of PAs (n = 150). These mutations aggregate within the 14-3-3 binding motif of USP8 and disrupt the interaction between USP8 and 14-3-3 protein, resulting in an elevated capacity to protect EGFR from lysosomal degradation. Accordingly, PAs with mutated USP8 display a higher incidence of EGFR expression, elevated EGFR protein abundance and mRNA expression levels of POMC, which encodes the precursor of ACTH. PAs with mutated USP8 are significantly smaller in size and have higher ACTH production than wild-type PAs. In surgically resected primary USP8-mutated tumor cells, USP8 knockdown or blocking EGFR effectively attenuates ACTH secretion. Taken together, somatic gain-of-function USP8 mutations are common and contribute to ACTH overproduction in Cushings disease. Inhibition of USP8 or EGFR is promising for treating USP8-mutated corticotrophin adenoma. Our study highlights the potentially functional mutated gene in Cushings disease and provides insights into the therapeutics of this disease.

miR-508-5p regulates multidrug resistance of gastric cancer by targeting ABCB1 and ZNRD1.

Multidrug resistance (MDR) is usually correlated with the poor prognosis of gastric cancer. In this study, we revealed a total of 11 microRNAs (miRNA) that regulated MDR of gastric cancer via high-throughput functional screening, and miR-508-5p reversed MDR most efficiently among these candidate miRNAs. The overexpression of miR-508-5p was sufficient to reverse cancer cell resistance to multiple chemotherapeutics in vitro and sensitize tumours to chemotherapy in vivo. Further studies showed that miR-508-5p could directly target the 3′-untranslated regions of ABCB1 and Zinc ribbon domain-containing 1 (ZNRD1), and suppress their expression at the mRNA and protein levels. Meanwhile, the suppression of ZNRD1 led to a decrease in ABCB1. These findings suggest that a miR-508-5p/ZNRD1/ABCB1 regulatory loop has a critical role in MDR in gastric cancer. In addition, miR-508-5p could be used as a prognostic factor for overall survival in gastric cancer. These data reveal an important role for miR-508-5p in the regulation of MDR in gastric cancer, and suggest the potential application of miR-508-5p in drug resistance prediction and treatment.

Association of Sequence Variants on Chromosomes 20, 11, and 5 (20q13.33, 11q23.3, and 5p15.33) With Glioma Susceptibility in a Chinese Population

Two genome-wide association studies of glioma in European populations identified 14 genetic variants strongly associated with risk of glioma, but it is unknown whether these variants are associated with glioma risk in Asian populations. The authors genotyped these 14 variants in 976 glioma patients and 1,057 control subjects to evaluate their associations with risk of glioma, particularly high-grade glioma (glioblastoma; n = 312), in a Chinese population (2004-2009). Overall, the authors identified 3 susceptibility loci for glioma risk at 20q13.33 (RTEL1 rs6010620 (P = 2.79 × 10(-6))), 11q23.3 (PHLDB1 rs498872 (P = 3.8 × 10(-6))), and 5p15.33 (TERT rs2736100 (P = 3.69 × 10(-4))) in this study population; these loci were also associated with glioblastoma risk (20q13.33: RTEL1 rs6010620 (P = 3.57 × 10(-7)); 11q23.3: PHLDB1 rs498872 (P = 7.24 × 10(-3)); 5p15.33: TERT rs2736100 and TERT rs2736098 (P = 1.21 × 10(-4) and P = 2.84 × 10(-4), respectively)). This study provides further evidence for 3 glioma susceptibility regions at 20q13.33, 11q23.3, and 5p15.33 in Chinese populations.

Transplantation of vascular endothelial growth factor-transfected neural stem cells into the rat brain provides neuroprotection after transient focal cerebral ischemia

OBJECTIVE:Vascular endothelial growth factor (VEGF) stimulation and neural stem cell (NSC) transplantation have been implicated in the treatment of cerebral ischemia because of their crucial roles in neuroprotection, neurogenesis, and angiogenesis. However, effective delivery of VEGF or NSCs remains difficult. This study attempted to explore whether VEGF121 complementary deoxyribonucleic acid could be transferred into the NSCs and, furthermore, whether transplanting these VEGF121-transfected NSCs into the rat brain provides sufficient neuroprotection after transient focal cerebral ischemia. METHODS:The VEGF121 gene was transfected to the NSCs isolated from E14 fetal rat hippocampus. In vitro studies revealed that VEGF messenger ribonucleic acid could be consistently expressed in NSCs from 1 day to up to 2 weeks. RESULTS:After transplantation of VEGF121-transfected NSCs into the perifocal area of the ischemic rat brain, we found that these cells could survive and migrate in the ischemic region for 12 weeks. Furthermore, we observed a significant improvement of the Neurological Severity Scale score in the rats transplanted with VEGF121-transfected NSCs in comparison to the phosphate-buffered saline-injected or the sham-operated rats (P < 0.05). Transplantation of nontransfected NSCs into ischemic rat brain improved the Neurological Severity Scale score as well. Of note, the improvement in the Neurological Severity Scale score occurred earlier in the VEGF121-transfected NSC rats than in the nontransfected NSC rats (range, 2–12 wk versus 8–12 wk), suggesting a potent neuroprotection mediated by additional VEGF121 transfection. CONCLUSION:We conclude that transplantation of VEGF121-transfected NSCs improved ischemic neurological deficiency. This finding provides a novel approach for the treatment of cerebral ischemia.

Diagnosis and surgical treatment of cavernous sinus hemangiomas: an experience of 20 cases

OBJECTIVE To elucidate the advances of diagnosis and surgical treatment of the cavernous sinus hemangiomas (CSHs). METHODS The data from 20 patients with the CSHs surgically treated by authors from 1996 through 2000 was analyzed retrospectively, and a review of relevant literature was conducted. RESULTS These 20 cases accounted for 16.3% of all intracranial cavernous hemangiomas surgically treated in the same period at Huashan Hospital. The patients were aged from 32 approximately 69 years with an average age of 47 years. There were 17 females and 3 males. The common clinical manifestations were visual loss, diplopia, headache, facial numbness and extraocular muscle palsy. Computed tomography (CT) and magnetic resonance imaging (MRI) were major preoperative diagnostic modalities, but demonstrated nonspecific features. The preoperative misdiagnostic rate was 38.9%. Of the 20 patients undergoing craniotomy via modified pterional approach with or without orbitozygomatic osteotomy, tumors were removed through epidural approach (EDA) in 13 cases, intradural approach (IDA) in 7 cases. Hypotension was induced during the operation in 2 cases. Total tumor removal was achieved in 12 cases (92.3%) in the EDA group and nil in the IDA group. Incomplete tumor removal was 1 case (7.7%) in the EDA group and 7 cases (100%) in the IDA group. One patient in the IDA group died of intracranial hemorrhage postoperatively. Compared with preoperative manifestations, cranial neuropathies at discharge were worsened in 76.9% of patients in the EDA group and 83.3% of patients in the IDA group, improved in 15.4% of patients in the EDA group and 16.7% of patients in the IDA group, unchanged in 7.7% of patients in the EDA group. Follow-up study (range, 1 approximately 6 years; mean, 3 years) was available in 17 patients (89%). All patients in the EDA group improved without tumor recurrence. Nonimprovement (2 cases) and continued worsening (3 cases) occurred in the IDA group. In patients with tumor incompletely removed, the tumor enlarged in 2 cases, and unchanged or decreased in size in 3 cases, in which 2 cases underwent postoperative radiosurgery or radiotherapy. According to pathologic and MRI characteristics, the CSHs can be divided into two types, sponge-like type and mulberry-like type. CONCLUSION Cavernous hemangioma should be included in differential diagnosis for middle aged females with cavernous sinus tumors. Two types of the CSHs, sponge-like type and mulberry-like type, can be identified. The best microsurgical approach for the removal of the CSHs is epidural approach via the skull-base craniotomy. Radiosurgery should be considered for patients with incomplete tumor removal.

Polymorphisms of LIG4 and XRCC4 Involved in the NHEJ Pathway Interact to Modify Risk of Glioma

Although the role of environmental risk factors in the etiology of gliomas remains to be elucidated, accumulative epidemiological evidence suggests that genetic factors, such as variants in genes involved in DNA repair, may also play an important role. LIG4 and XRCC4 are known to form a complex and are functionally linked in the repair of double‐stranded DNA breaks. To determine whether LIG4 and XRCC4 polymorphisms are associated with susceptibility to glioma and whether there are interactions between LIG4 and XRCC4, we conducted a case–control study of 771 glioma patients and 752 cancer‐free controls, assessed the associations between glioma risk and 20 tagging SNPs, and evaluated their potential gene–gene interactions using the multifactor dimensionality reduction (MDR), interaction dendrogram, and entropy analysis. In the single‐locus analysis, only one variant, the LIG4 SNP2 rs3093739:T>C (P‐permutation=0.009) was significantly associated with risk of developing glioma. Haplotype analysis revealed an association of glioma risk with genetic variants in LIG4 block 1 (global P=0.011), and XRCC4 blocks 2 and 4 (both global P<0.0001). Moreover, the MDR analysis suggested a significant three‐locus interaction model involving LIG4 SNP4 rs1805388:C>T, XRCC4 SNP12 rs7734849:A>T, and SNP15 rs1056503:G>T. Further dendrogram and graph analysis indicated a more‐than‐additive effect among these three loci. These results suggested that these variants may contribute to glioma susceptibility. Hum Mutat 29(3), 381–389, 2008.

Transsphenoidal pituitary macroadenomas resection guided by PoleStar N20 low-field intraoperative magnetic resonance imaging: comparison with early postoperative high-field magnetic resonance imaging.

OBJECTIVETo evaluate the applicability of low-field intraoperative magnetic resonance imaging (iMRI) during transsphenoidal surgery of pituitary macroadenomas. METHODSFifty-five transsphenoidal surgeries were performed for macroadenomas (modified Hardys Grade II–IV) resections. All of the surgical processes were guided by real-time updated contrast T1-weighted coronal and sagittal images, which were acquired with 0.15 Tesla PoleStar N20 iMRI (Medtronic Navigation, Louisville, CO). The definitive benefits as well as major drawbacks of low-field iMRI in transsphenoidal surgery were assessed with respect to intraoperative imaging, tumor resection control, comparison with early postoperative high-field magnetic resonance imaging, and follow-up outcomes. RESULTSIntraoperative imaging revealed residual tumor and guided extended tumor resection in 17 of 55 cases. As a result, the percentage of gross total removal of macroadenomas increased from 58.2% to 83.6%. The accuracy of imaging evaluation of low-field iMRI was 81.8%, compared with early postoperative high-field MRI (Correlation coefficient, 0.677; P < 0.001). A significantly lower accuracy was identified with low-field iMRI in 6 cases with cavernous sinus invasion (33.3%) in contrast to the 87.8% found with other sites (Fishers exact test, P < 0.001). CONCLUSIONThe PoleStar N20 low-field iMRI navigation system is a promising tool for safe, minimally invasive, endonasal, transsphenoidal pituitary macroadenomas resection. It enables neurosurgeons to control the extent of tumor resection, particularly for suprasellar tumors, ensuring surgical accuracy and safety, and leading to a decreased likelihood of repeat surgeries. However, this technology is still not satisfying in estimating the amount of the parasellar residual tumor invading into cavernous sinus, given the false or uncertain images generated by low-field iMRI in this region, which are difficult to discriminate between tumor remnant and blood within the venous sinus.

Dual-targeted antitumor effects against brainstem glioma by intravenous delivery of tumor necrosis factor-related, apoptosis-inducing, ligand-engineered human mesenchymal stem cells.

OBJECTIVEWe sought to explore the dual-targeted antitumor effects of membrane-spanned, tumor necrosis factor-related, apoptosis-inducing ligand (TRAIL)-engineered human mesenchymal stem cells (hMSCs) against brainstem gliomas. METHODSThe migration capacity of hMSCs toward gliomas was studied by the Transwell system in vitro and by intravenous injection of hMSCs in glioma-bearing mice in vivo. MSCs were engineered with native full-length human TRAIL (hTRAIL) by a recombinant adeno-associated virus (rAAV) vector (rAAV-hTRAIL). The targeted antiglioma effect was analyzed by coculture of hTRAIL-engineered MSCs with glioma in vitro and by systematic delivery of hTRAIL-engineered MSCs to established human brainstem glioma xenografts. RESULTSWe demonstrated systematically that transplanted MSCs migrated to a brainstem glioma with a high specificity. MSCs penetrated the vessels surrounding the tumor, then streamed in a chain pattern toward the glioma, eventually surrounding the tumor. Membrane-spanned, TRAIL-engineered MSCs not only expressed full-length TRAIL in MSC surface, but secreted some soluble TRAIL in medium. After being infected with rAAV-hTRAIL, hMSCs showed no increase in apoptosis. After coculture of hTRAIL-engineered MSCs and U87MG cells, the apoptosis of U87MG cells significantly increased more than soluble TRAIL-treated U87MG cells. Systematic delivery of hTRAIL-engineered MSCs to established human brainstem glioma xenografts resulted in the potent induction of apoptosis in gliomas, but not in normal brain and prolonged survival to 38.0 ± 10.46 days compared with phosphate-buffered saline (16.0 ± 0.66 days), soluble TRAIL (19.0 ± 1.65 days), and hMSC-LacZ (14.0 ± 0.59 days) treated groups. CONCLUSIONSystematically transplanted MSCs migrated to gliomas with a high specificity. Systematic delivery of MSC-hTRAIL can prolong the survival of brainstem glioma-bearing mice, presumably through a dual-targeted effect of membrane-spanned, TRAIL-engineered MSCs in the tumor microenvironment. MSCs may be an effective vehicle for the targeted delivery of therapeutic agents to brainstem gliomas.