Jia Wei Lin

The impact of time, legislation, and geography on the epidemiology of traumatic brain injury

In 1991, a population-based epidemiologic traumatic brain injury (TBI) study was done in urban and rural areas of Taiwan; this was 5 years before the helmet use law was passed and 8 years before the drink driving law was passed. In order to evaluate the impact of three major determinants (time, geography, and legislation) on the epidemiology of TBI, we conducted a prospective study in 2001 and used the 1991 data to examine the differences in TBI distribution in urban and rural Taiwan a decade after these laws were passed. In 2001, 5754 TBI cases were collected from the urban area of Taipei City, and 1474 TBI cases were collected from the rural area of Hualien County. The TBI incidence rate in Taipei City in 2001 was estimated to be 218/100,000 population (285/100,000 for males and 152/100,000 for females). When compared to the 1991 data, the incidence rate in 2001 had increased by 20%. The TBI incidence rate in Hualien County in 2001 was estimated to be 417/100,000 population (516/100,000 for males and 306/100,000 for females); this was a 37% increase over the 1991 data. Our study found that the distribution of causes and age distribution had shifted significantly over the 10-year period. In 2001, the age group with the highest incidence was 20-29 years, while in 1991 it had been the over 70 years age group. While traffic-related TBI had decreased, falls and assaults had increased in 2001. We also found that legislation, such as the helmet law, affects TBI distribution by decreasing the traffic-related TBI rate, decreasing the admission severity of TBI, and reducing TBI-related mortality. Finally, geography plays a crucial role in the outcome of TBI; over the 10 year period, Taipei had an increase in moderately severe outcomes, while Hualien had an increase in more severe outcomes. Comparative studies of TBI in urban and rural areas have shown that time, legislation, and geography are crucial determinants of TBI epidemiology. Although time and legal interventions seem to have more of an impact, geography does affect TBI outcomes.

Uric acid activates extracellular signal-regulated kinases and thereafter endothelin-1 expression in rat cardiac fibroblasts

BACKGROUND The association between hyperuricemia and cardiovascular diseases has long been recognized. Elevated levels of uric acid may have a causal role in hypertension and cardiovascular diseases. However, the direct effect of uric acid on cardiac cells remains unclear. Therefore, this study was aimed to examine the effect of uric acid in rat cardiac fibroblasts and to identify the putative underlying signaling pathways. METHODS Cultured rat cardiac fibroblasts were stimulated with uric acid; cell proliferation and endothelin-1 (ET-1) gene expression were examined. The effect of uric acid on NADPH oxidase activity, reactive oxygen species (ROS) formation, and extracellular signal-regulated kinases (ERK) phosphorylation were tested to elucidate the intracellular mechanism of uric acid in ET-1 gene expression. RESULTS Uric acid-increased cell proliferation and ET-1 gene expression. Uric acid also increased NADPH oxidase activity, ROS formation, ERK phosphorylation, and activator protein-1 (AP-1)-mediated reporter activity. Antioxidants suppressed uric acid-induced ET-1 gene expression, and ERK phosphorylation, and AP-1 reporter activities. Mutational analysis of the ET-1 gene promoter showed that AP-1 binding site was an important cis-element in uric acid-induced ET-1 gene expression. CONCLUSIONS These results suggest that uric acid-induced ET-1 gene expression, partially by the activation of ERK pathway via ROS generation in cardiac fibroblasts.

Uric acid stimulates endothelin-1 gene expression associated with NADPH oxidase in human aortic smooth muscle cells

AbstractAim:Recent experimental and human studies have shown that hyperuricemia is associated with hypertension and cardiovascular diseases. Elevated levels of endothelin-1 (ET-1) has been regarded as one of the most powerful independent predictors of cardiovascular diseases. For investigating whether uric acid-induced vascular diseases are related to ET-1, the uric acid-induced ET-1 expression in human aortic smooth muscle cells (HASMC) was examined.Methods:Cultured HASMC treated with uric acid, cell proliferation and ET-1 expression were examined. Antioxidant pretreatments on uric acid-induced extracellular signal-regulated kinases (ERK) phosphorylation were carried out to elucidate the redox-sensitive pathway in proliferation and ET-1 gene expression.Results:Uric acid was found to increase HASMC proliferation, ET-1 expression and reactive oxygen species production. The ability of both N-acetylcysteine and apo-cynin (l-[4-hydroxy-3-methoxyphenyl]ethanone, a NADPH oxidase inhibitor) to inhibit uric acid-induced ET-1 secretion and cell proliferation suggested the involvement of intracellular redox pathways. Furthermore, apocynin, and p47phox small interfering RNA knockdown inhibited ET-1 secretion and cell proliferation induced by uric acid. Inhibition of ERK by U0126 (1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio]butadiene) significantly suppressed uric acid-induced ET-1 expression, implicating this pathway in the response to uric acid. In addition, uric acid increased the transcription factor activator protein-1 (AP-1) mediated reporter activity, as well as the ERK phosphorylation. Mutational analysis of the ET-1 gene promoter showed that the AP-1 binding site was an important cis-element in uric acid-induced ET-1 gene expression.Conclusion:This is the first observation of ET-1 regulation by uric acid in HASMC, which implicates the important role of uric acid in the vascular changes associated with hypertension and vascular diseases.

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.

Antiproliferative Effect of Isosteviol on Angiotensin-II-Treated Rat Aortic Smooth Muscle Cells

Isosteviol is a derivative of stevioside, a constituent of Stevia rebaudiana, which is commonly used as a noncaloric sugar substitute in Japan and Brazil. The aims of this study were to examine whether isosteviol alters angiotensin-II-induced cell proliferation in rat aortic smooth muscle cells. Cultured rat aortic smooth muscle cells were preincubated with isosteviol, then stimulated with angiotensin II, after which [3H]thymidine incorporation and endothelin-1 secretion were examined. Isosteviol (1–100 µmol/l) inhibits angiotensin-II-induced DNA synthesis and endothelin-1 secretion. Measurements of 2′7′-dichlorofluorescin diacetate, a redox-sensitive fluorescent dye, showed an isosteviol-mediated inhibition of intracellular reactive oxygen species generated by the effects of angiotensin II. The inductive properties of angiotensin II on extracellular signal-regulated kinase (ERK) phosphorylation were found reversed with isosteviol and antioxidants such as N-acetylcysteine. In summary, we speculate that isosteviol inhibits angiotensin-II-induced cell proliferation and endothelin-1 secretion via attenuation of reactive oxygen species generation. Thus, this study provides important insights that may contribute to the effects of isosteviol on the cardiovascular system.

Curcumin Attenuates the Expression and Secretion of RANTES after Spinal Cord Injury In Vivo and Lipopolysaccharide-Induced Astrocyte Reactivation In Vitro

Curcumin has been proposed for treatment of various neuroinflammatory and neurodegenerative conditions, including post-traumatic inflammation during acute spinal cord injury (SCI). In this study, we examined whether curcumin anti-inflammation involves regulation of astrocyte reactivation, with special focus on the injury-induced RANTES (regulated on expression normal T-cell expressed and secreted) from astrocytes in acute SCI. Male Sprague-Dawley (SD) rats were subjected to impact injury of the spinal cord followed by treatment with curcumin (40 mg/kg i.p.). RANTES and inducible nitric oxide synthase expression as well as RANTES-positive astrocytes were all induced by injury accompanied by the elevation of lipid peroxidation, and attenuated by the curcumin treatment. In primary cultured rat astrocytes challenged with lipopolysaccharide (LPS) to mimic astrocyte reactivation following SCI, LPS induces robust increase of RANTES expression and the effect was also reduced by 1 μM curcumin treatment. Furthermore, cortical neurons cultured with astrocyte conditioned medium (ACM) conditioned with both LPS and curcumin (LPS-curcumin/ACM), which characteristically exhibited decreased RANTES expression when compared with ACM from astrocytes treated with LPS alone (LPS/ACM), showed higher level of cell viability and lower level of cell death as assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction activity assay and lactate dehydrogenase release assay, respectively. Knockdown of RANTES expression by siRNA (siRANTES) shows reduced RANTES expression and release from LPS-reactivated astrocytes, and ACM obtained from this condition (LPS-siRANTES/ACM) becomes less cytotoxic as compared with the LPS-ACM. Therefore, curcumin reduction of robust RANTES production in reactivated astrocytes both in vitro and in vivo may contribute to its neuroprotection and potential application in SCI.

Correlation between Glasgow coma score components and survival in patients with traumatic brain injury

BACKGROUND The Glasgow coma scale (GCS) score is used in the initial evaluation of patients with traumatic brain injury (TBI); however, the determination of an accurate score is not possible in all clinical situations. Our aim is to determine if the individual components of the GCS score, or combinations of them, are useful in predicting mortality in patients with TBI. METHODS The components of the GCS score and the receiver-operating characteristic (ROC) curves were analyzed from 27,625 cases of TBI in Taiwan. RESULTS The relationship between the survival rate and certain eye (E), motor (M) and verbal (V) score combinations for GCS scores of 6, 11, 12 and 13 were statistically significant. The areas under ROC curve of E+V, M+V and M alone were 0.904, 0.903 and 0.900, respectively, representing the 3 most precise combinations for predicting mortality. The area under the ROC curve for the complete GCS score (E+M+V) was 0.885. Patients with lower E, M and V score respectively, and lower complete GCS scores had higher hazard of death than those with the highest scores. CONCLUSION The results of this study indicate that the 3 fundamental elements comprising the Glasgow coma scale, E, M, and V individually, and in certain combinations are predictive of the survival of TBI patients. This observation is clinically useful when evaluating TBI patients in whom a complete GCS score cannot be obtained.

Curcumin enhances neuronal survival in N-methyl-d-aspartic acid toxicity by inducing RANTES expression in astrocytes via PI-3K and MAPK signaling pathways.

OBJECT Neuroinflammation, which is characterized by the overproduction of cytokines and chemokines, plays an important role in neurodegenerative diseases, especially in Alzheimers disease (AD). In the brain, chemokines are predominantly released by astrocytes and microglias. Expression of RANTES, as well as other cytokines, is involved in the inflammatory cascade that contributes to neurodegeneration in AD. Expression of RANTES may also have a neuroprotective effect. We sought to investigate whether curcumin exhibited neuroprotective and antioxidant activity via enhanced RANTES expression by astrocytes in cortical neuron cultures. We evaluated the neuroprotective and anti-neurodegenerative effects of curcumin in NMDA toxicity and in long-term cultures. METHODS Pregnant female Sprague-Dawley (SD) rats were used for primary culture of cortical neurons, and neonatal 0- to 2-day-old SD rats were used for primary culture of astrocytes. Cultured astrocytes were conditioned with curcumin to prepare astrocyte-conditioned medium (ACM). Real-time polymerase chain reaction was performed to assess RANTES and iNOS mRNA expression in astrocytes following curcumin treatment. ELISA was used to detect astrocyte-secreted RANTES protein in ACM with curcumin treatment. JAK/STAT, PI-3K, PKC and MAPK inhibitors were used to ascertain whether the effects of curcumin involved these signaling pathways. To evaluate the effects of curcumin-enhanced astrocytes on neuronal survival, cultured cortical neurons treated or untreated with NMDA were incubated in ACM with or without curcumin treatment. Long-term culture (15days in vitro, DIV) was performed to investigate the effects of curcumin-treated astrocytes on the survival of cultured cortical neurons. Neuronal survival rate was assessed by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction activity assay (for cell viability), and the lactate dehydrogenase (LDH) release assay (for cell death). RESULTS We demonstrated that curcumin enhanced RANTES expression in primary cultured astrocytes, and that this effect was related to activation of PI-3K and MAPK signaling pathways. We found that curcumin inhibited iNOS expression in primary cultured astrocytes in non-stressed condition. We also found that neurons exposed to NMDA and cultured with curcumin treated ACM, which characteristically exhibited elevated RANTES expression showed higher level of cell viability and lower level of cell death. Using a small interfering RNA (siRNA) knockdown model, we found evidence that the basal level of RANTES expression in non-stimulated astrocytes provided neuroprotection. CONCLUSION We postulate that the enhanced neuronal survival by curcumin treatment in NMDA toxicity and long-term cultures was in part attributable to elevated astrocyte-derived RANTES expression via activation of PI3K/MAPK signaling pathways.

Urotensin II-induced endothelin-1 expression and cell proliferation via epidermal growth factor receptor transactivation in rat aortic smooth muscle cells

Urotensin II (U-II) is implicated in vascular smooth muscle cell proliferation, which results in vascular remodeling. We recently demonstrated that both reactive oxygen species (ROS) generation and epidermal growth factor receptor (EGFR) transactivation play critical roles in U-II signal transduction. However, the detailed intracellular mechanism of U-II in vascular smooth muscle cells remains unclear. In this study, we used rat aortic smooth muscle cells treated with U-II to investigate the connection between ROS generation and EGFR transactivation. U-II treatment was found to stimulate endothelin-1 (ET-1) expression and cell proliferation through the phosphorylation of EGFR and ROS generation. NAD(P)H oxidase inhibitor apocynin and ROS scavenger N-acetylcysteine (NAC) inhibited the EGFR transactivation induced by U-II. In contrast, AG-1478 (an EGFR inhibitor) failed to inhibit intracellular ROS generation induced by U-II. Src homology 2-containing tyrosine phosphatase (SHP-2) was shown to be associated with EGFR during U-II treatment by EGFR coimmunoprecipitation. ROS have been reported to oxidize the catalytic cysteine of SHP-2 and inhibit its activity. We examined the effect of U-II on SHP-2 in smooth muscle cells using a modified malachite green phosphatase assay. SHP-2 was oxidized during U-II treatment; and this oxidization could be repressed by NAC treatment. In SHP-2 knockdown cells, U-II-induced EGFR phosphorylation, ET-1 secretion, and cell proliferation were enhanced, and were not influenced by NAC. Our data suggest that U-II-mediated ROS generation can inhibit SHP-2 activity to facilitate the EGFR transactivation and mitogenic signal transduction in rat aortic smooth muscle cells.

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.