Chien Min Lin

Hyaluronic acid inhibits the glial scar formation after brain damage with tissue loss in rats.

BACKGROUND Brain tissue scarring (gliosis) was believed to be the major cause of epileptic focus after brain injury, and prevention of scarring could reduce the incidence of seizure. We tried the HA coating onto the cortical brain defect of Spraque-Dawley rats to reduce the marginal glial scarring. METHODS A 4 x 2 x 2 mm(3) cortical defect was created in the brain of Spraque-Dawley rats. Three percent HA gel was coated onto the lesion for the experimental groups and normal saline solutions for the control groups. The brain was retrieved 4, 8, and 12 weeks after treatment. The brains were then sectioned and processed for H&E and GFAP staining, and the thickness of the scarring and the number of GFAP+ cells were analyzed. RESULTS The thickness of cutting marginal gliosis was significantly decreased in the HA groups. The 12-week HA group showed the smallest thickness of gliosis, whereas the 12-week control group exhibited the largest thickness of gliosis. The significant difference in the thickness of gliosis was also noted between the HA and the control groups 8 weeks after treatment. The number of GFAP+ cells was also significantly decreased in the HA groups when compared to the respective control group 4, 8, and 12 weeks after the surgery. CONCLUSION The results support the hypothesis that HA inhibits glial scarring not only by decreasing the thickness of gliosis but also by reducing the number of the glial cells. Furthermore, our results suggest that HA might be used to reduce glial scar formation in central nervous system surgery, which subsequently prevents the post-operation or posttraumatic seizure incidence.

Attenuating Experimental Spinal Cord Injury by Hyperbaric Oxygen: Stimulating Production of Vasculoendothelial and Glial Cell Line-Derived Neurotrophic Growth Factors and Interleukin-10

The present study was carried out to further examine the mechanisms underlying the beneficial effects of hyperbaric oxygen (HBO(2)) on experimental spinal cord injury (SCI). Rats were divided into three major groups: (1) sham operation (laminectomy only); (2) laminectomy + SCI + normobaric air (NBA; 21% oxygen at 1 ATA); and (3) laminectomy + SCI + HBO(2) (100% oxygen at 2.5 ATA for 2 h). Spinal cord injury was induced by compressing the spinal cord for 1 min with an aneurysm clip calibrated to a closing pressure of 55 g. HBO(2) therapy was begun immediately after SCI. Behavioral tests of hindlimb motor function as measured by the Basso, Beattie, and Bresnahan (BBB) locomotor scale was conducted on days 1-7 post-SCI. The triphenyltetrazolium chloride staining assay and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick-end labeling assay were also conducted after SCI to evaluate spinal cord infarction and apoptosis, respectively. Cells positive for glial cell line-derived neurotrophic nerve growth factor (GDNF) and vascular endothelial growth factor (VEGF) and cytokines in the injured spinal cord were assayed by immunofluorescence and commercial kits, respectively. It was found that HBO(2) therapy significantly attenuated SCI-induced hindlimb dysfunction, and spinal cord infarction and apoptosis, as well as overproduction of spinal cord interleukin-1beta and tumor necrosis factor-alpha. In contrast, the numbers of both GDNF-positive and VEGF-positive cells and production of spinal cord interleukin-10 after SCI were all significantly increased by HBO(2). These data suggest that HBO(2) may attenuate experimental SCI by stimulating production of GDNF, VEGF, and interleukin-10.

Neurocytoprotective effects of the bioactive constituents of Pueraria thomsonii in 6-hydroxydopamine (6-OHDA)-treated nerve growth factor (NGF)-differentiated PC12 cells

Chronic neurodegenerative disorders are having an increasing impact on public health as human longevity increases. Parkinsons disease (PD) is a degenerative disorder of the central nervous system and is characterized by motor system disorders resulting in loss of dopamine-producing brain cells. Pueraria thomsonii Benth. (Fabaceae) is an herbal medicine that has traditionally been used as an antipyretic agent. In the present study, the active constituents, daidzein and genistein, were isolated from P. thomsonii. Both compounds exhibited neurocytoprotective effects against 6-hydroxydopamine (6-OHDA)-induced cytotoxicity in nerve growth factor (NGF)-differentiated PC12 cells. Neither daidzein nor genistein affected 6-OHDA-induced cellular reactive oxygen species (ROS) generation according to flow cytometric analysis. Rather, they inhibited caspase-8 and partially inhibited caspase-3 activation, providing a protective mechanism against 6-OHDA-induced cytotoxicity in NGF-differentiated PC12 cells. The present results imply that daidzein and genistein may be useful in the development of future strategies for the treatment of PD.

Neurotrauma research in Taiwan

Because of the rapid industrial and economic growth, Taiwan and other developing countries have faced an enormous increase in the number of motorcycles, which has subsequently caused a rapid increase of the motorcycle-related traumatic brain injuries (TBI). In order to tackle this serious problem, stepwise approaches for TBI were implemented in Taiwan from 1991 to 2007. Step 1 was to do a nationwide TBI registry in order to identify the risk factors and determinants. We found that the major cause of TBI in Taiwan was motorcycle-related injury, and very few motorcyclists wore a helmet. Step 2 was to launch the implementation of the helmet use law on June 1, 1997. A rapid decline of TBI hospitalizations and deaths was demonstrated soon thereafter. Step 3 was to enroll into international collaborations with the Global Spine and Head Injury Prevention Project (Global SHIP Project) groups for TBI. The comparative results thus obtained could be used to develop prevention strategies for developing countries. Step 4 was to implement clinical researches for TBI, which included a Propofol study, hyperbaric oxygen therapy (HBOT), brain parenchymal oxygen (PbtO2) monitoring, etc. Step 5 was to develop guidelines for the management of severe TBI in Taiwan. Through a 2-year period of review, discussion, and integration, a 9-chapter guideline was published in June 2007. In summary, our experience and process for management of TBI in Taiwan can be used as a reference for other developing countries.

Pterostilbene suppressed irradiation-resistant glioma stem cells by modulating GRP78/miR-205 axis

Glioblastoma multiforme (GBM) is the most aggressive type characterized by relapse and resistance even with the combination of radio- and chemotherapy. The presence of glioma stem cells (GSCs) has been shown to contribute to tumorigenesis, recurrence and treatment resistance. Particularly, CD133-positive glioma cells have been shown to represent the subpopulation that confers glioma radioresistance and suggested to be the source of tumor recurrence after radiation. Thus, a better understanding and the development of agents which target GSCs could potentially lead to a significant improvement in treating GBM patients. Here, we demonstrated that GRP78 (an antistress protein) was highly expressed in GBM cells along with β-catenin and Notch and correlated to the development of GSCs. CD133+ GSCs exhibited enhanced migration/invasion and self-renewal abilities. When GRP78 was silenced, GSC properties were suppressed and the sensitivity towards irradiation increased. In addition, the level of microRNA 205 appeared to be negatively associated with GRP78 expression. Our previous study indicated that pterostilbene (PT) possessed anticancer stem cell properties in hepatocellular carcinoma. Thus, we examined whether PT is also effective against GSCs. We found that PT-treated GSCs exhibited suppressed self-renewal and irradiation-resistant abilities. PT-mediated effects were associated with an increase of miR-205. Finally, we showed that PT treatment suppressed tumorigenesis in GSC xenograft mice. In conclusion, we provided evidence that GRP78/miR-205 axis played an important role in GSC maintenance and irradiation resistance. PT treatment suppressed GSC development via negatively modulating GRP78 signaling. PT may be considered for combined therapeutic agent to enhance irradiation efficacy in GBM patients.

Preclinical investigation of ibrutinib, a Bruton’s kinase tyrosine (Btk) inhibitor, in suppressing glioma tumorigenesis and stem cell phenotypes

Standard interventions for glioma include surgery, radiation and chemotherapies but the prognosis for malignant cases such as glioblastoma multiforme remain grim. Even with targeted therapeutic agent, bevacitumab, malignant glioma often develops resistance and recurrence. Thus, developing alternative interventions (therapeutic targets, biomarkers) is urgently required. Brutons tyrosine kinase (Btk) has been long implicated in B cell malignancies but surprisingly it has recently been shown to also play a tumorigenic role in solid tumors such as ovarian and prostate cancer. Bioinformatics data indicates that Btk is significantly higher in clinical glioma samples as compared to normal brain cells and Btk expression level is associated with stage progression. This prompts us to investigate the potential role of Btk as a therapeutic target for glioma. Here, we demonstrate Btk expression is associated with GBM tumorigenesis. Down-regulation of Btk in GBM cell lines showed a significantly reduced abilities in colony formation, migration and GBM sphere-forming potential. Mechanistically, Btk-silenced cells showed a concomitant reduction in the expression of CD133 and Akt/mTOR signaling. In parallel, Ibrutinib (a Btk inhibitor) treatment led to a similar anti-tumorigenic response. Using xenograft mouse model, tumorigenesis was significantly reduced in Btk-silenced or ibrutinib-treated mice as compared to control counterparts. Finally, our glioma tissue microarray analysis indicated a higher Btk staining in the malignant tumors than less malignant and normal brain tissues. Collectively, Btk may represent a novel therapeutic target for glioma and ibrunitib may be used as an adjuvant treatment for malignant GBM.

Clinical practice guidelines in severe traumatic brain injury in Taiwan

BACKGROUND Severe TBIs are major causes of disability and death in accidents. The Brain Trauma Foundation supported the first edition of the Guidelines for the Management of Severe Traumatic Brain Injury in 1995 and revised it in 2000. The recommendations in these guidelines are well accepted in the world. There are still some different views on trauma mechanisms, pathogenesis, and managements in different areas. Individualized guidelines for different countries would be necessary, and Taiwan is no exception. METHODS In November 2005, we organized the severe TBI guidelines committee and selected 9 topics, including ER treatment, ICP monitoring, CPP, fluid therapy, use of sedatives, nutrition, intracranial hypertension, seizure prophylaxis, and second-tier therapy. We have since searched key questions in these topics on Medline. References are classified into 8 levels of evidence: 1++, 1+, 1-, 2++, 2+, 2-, 3, and 4 based on the criteria of the SIGN. RESULTS Recommendations are formed and graded as A, B, C, and D. Grade A means that at least one piece of evidence is rated as 1++, whereas grade B means inclusion of studies rated as 2++. Grade C means inclusion of references rated as 2+, and grade D means levels of evidence rated as 3 or 4. Overall, 42 recommendations are formed. Three of these are rated as grade A, 13 as grade B, 21 as grade C, and 5 as grade D. CONCLUSIONS We have completed the first evidence-based, clinical practice guidelines for severe TBIs. It is hoped that the guidelines will provide concepts and recommendations to promote the quality of care for severe TBIs in Taiwan.

A Prospective Randomized Study of Brain Tissue Oxygen Pressure-Guided Management in Moderate and Severe Traumatic Brain Injury Patients

The purpose of this study was to compare the effect of PbtO2-guided therapy with traditional intracranial pressure- (ICP-) guided treatment on the management of cerebral variables, therapeutic interventions, survival rates, and neurological outcomes of moderate and severe traumatic brain injury (TBI) patients. From 2009 to 2010, TBI patients with a Glasgow coma scale <12 were recruited from 6 collaborative hospitals in northern Taiwan, excluding patients with severe systemic injuries, fixed and dilated pupils, and other major diseases. In total, 23 patients were treated with PbtO2-guided management (PbtO2 > 20 mmHg), and 27 patients were treated with ICP-guided therapy (ICP < 20 mmHg and CPP > 60 mmHg) in the neurosurgical intensive care unit (NICU); demographic characteristics were similar across groups. The survival rate in the PbtO2-guided group was also significantly increased at 3 and 6 months after injury. Moreover, there was a significant correlation between the PbtO2 signal and Glasgow outcome scale-extended in patients from 1 to 6 months after injury. This finding demonstrates that therapy directed by PbtO2 monitoring is valuable for the treatment of patients with moderate and severe TBI and that increasing PaO2 to 150 mmHg may be efficacious for preventing cerebral hypoxic events after brain trauma.

Garcinol downregulates Notch1 signaling via modulating miR‐200c and suppresses oncogenic properties of PANC‐1 cancer stem‐like cells

Pancreatic cancer represents one of the most aggressive types of malignancy due to its high resistance toward most clinically available treatments. The presence of pancreatic cancer stem‐like cells (CSCs) has been attributed to the intrinsically high resistance and highly metastatic potential of this disease. Here, we identified and isolated pancreatic CSCs using the side population (SP) method from human pancreatic cancer cell line, PANC‐1. We then compared the SP and non‐SP PANC‐1 cells genetically. PANC‐1 SP cells exhibited CSC properties including enhanced self‐renewal ability, increased metastatic potential, and resistance toward gemcitabine treatment. These cancer stem‐like phenotypes were supported by their enhanced expression of ABCG2, Oct4, and CD44. A traditional plant‐derived antioxidant, garcinol, has been implicated for its anticancer properties. Here, we found that garcinol treatment to PANC‐1 SP cells significantly suppressed the stem‐like properties of PANC‐1 SP cells and metastatic potential by downregulating the expression of Mcl‐1, EZH2, ABCG2, Gli‐1, and Notch1. More importantly, garcinol treatment led to the upregulation of several tumor suppressor microRNAs, and miR‐200c increased by garcinol treatment was found to target and downregulate Notch1. Thus, PANC‐1 SP cells may serve as a model for studying drug‐resistant pancreatic CSCs, and garcinol has the potential as an antagonist against pancreatic CSCs.

Comparing Miniopen and Minimally Invasive Transforaminal Interbody Fusion in Single-Level Lumbar Degeneration

Degenerative diseases of the lumbar spine, which are common among elderly people, cause back pain and radicular symptoms and lead to a poor quality of life. Lumbar spinal fusion is a standardized and widely accepted surgical procedure used for treating degenerative lumbar diseases; however, the classical posterior approach used in this procedure is recognized to cause vascular and neurologic damage of the lumbar muscles. Various studies have suggested that using the minimally invasive transforaminal interbody fusion (TLIF) technique provides long-term clinical outcomes comparable to those of open TLIF approaches in selected patients. In this study, we compared the perioperative and short-term advantages of miniopen, MI, and open TLIF. Compared with open TLIF, MI-TLIF and miniopen TLIF were associated with less blood loss, shorter hospital stays, and longer operative times; however, following the use of these procedures, no difference in quality of life was measured at 6 months or 1 year. Whether miniopen TLIF or MI-TLIF can replace traditional TLIF as the surgery of choice for treating degenerative lumbar deformity remains unclear, and additional studies are required for validating the safety and efficiency of these procedures.