Kyung Ha Choi

Electroacupuncture Acutely Improves Cerebral Blood Flow and Attenuates Moderate Ischemic Injury via an Endothelial Mechanism in Mice

Electroacupuncture (EA) is a novel therapy based on traditional acupuncture combined with modern eletrotherapy that is currently being investigated as a treatment for acute ischemic stroke. Here, we studied whether acute EA stimulation improves tissue and functional outcome following experimentally induced cerebral ischemia in mice. We hypothesized that endothelial nitric oxide synthase (eNOS)-mediated perfusion augmentation was related to the beneficial effects of EA by interventions in acute ischemic injury. EA stimulation at Baihui (GV20) and Dazhui (GV14) increased cerebral perfusion in the cerebral cortex, which was suppressed in eNOS KO, but there was no mean arterial blood pressure (MABP) response. The increased perfusion elicited by EA were completely abolished by a muscarinic acetylcholine receptor (mAChR) blocker (atropine), but not a β-adrenergic receptor blocker (propranolol), an α-adrenergic receptor blocker (phentolamine), or a nicotinic acetylcholine receptor (nAChR) blocker (mecamylamine). In addition, EA increased acetylcholine (ACh) release and mAChR M3 expression in the cerebral cortex. Acute EA stimulation after occlusion significantly reduced infarct volume by 34.5% when compared to a control group of mice at 24 h after 60 min-middle cerebral artery occlusion (MCAO) (moderate ischemic injury), but not 90-min MCAO (severe ischemic injury). Furthermore, the impact of EA on moderate ischemic injury was totally abolished in eNOS KO. Consistent with a smaller infarct size, acute EA stimulation led to prominent improvement of neurological function and vestibule-motor function. Our results suggest that acute EA stimulation after moderate focal cerebral ischemia, but not severe ischemia improves tissue and functional recovery and ACh/eNOS-mediated perfusion augmentation might be related to these beneficial effects of EA by interventions in acute ischemic injury.

Self-assembled nanoparticles of hyaluronic acid/poly(dl-lactide-co-glycolide) block copolymer

We synthesized block copolymer composed of hyaluronic acid (HA) and poly(DL-lactide-co-glycolide) (PLGA) (HAbLG) for antitumor targeting. (1)H NMR was employed to confirm synthesis of block copolymer. At (1)H NMR study, HabLG nanoparticles showed HA intrinsic peaks only at D(2)O, indicating that they contained HA as a hydrophilic outer-shell and PLGA as a inner-core. Anti-tumor activity was studied using CD44-overexpressing HCT-116 human colon carcinoma cells. Addition of doxorubicin (DOX)-incorporated nanoparticles to tumor cells resulted in the expression of a strong red fluorescence color while they expressed very weak fluorescence when CD44 receptor was blocked with free HA. Flow cytometry data also showed similar results, indicating that the fluorescence intensity of tumor cells treated with nanoparticles was significantly decreased when CD44 receptor was blocked. These results indicate that HAbLG nanoparticles were able to target CD44-overexpressing tumor cells via receptor-mediated endocytosis.

Electroacupuncture preconditioning reduces cerebral ischemic injury via BDNF and SDF-1α in mice

BackgroundThis study was designed to determine if electroacupuncture (EA) preconditioning improves tissue outcome and functional outcome following experimentally induced cerebral ischemia in mice. In addition, we investigated whether the expression of brain-derived neurotrophic factor (BDNF) and stromal cell derived factor-1α (SDF-1α) and infarct volume were related with improvement in neurological and motor function by interventions in this study.MethodsAfter treatment with EA at the acupoints ‘Baihui (GV20)’ and ‘Dazhui (GV14)’ for 20 min, BDNF was assessed in the cortical tissues based on Western blot and the SDF-1α and vascular endothelial growth factor (VEGF) levels in the plasma determined by ELISA. To assess the protective effects of EA against ischemic injury, the mice received once a day 20 min EA preconditioning for three days prior to the ischemic event. Focal cerebral ischemia was then induced by photothrombotic cortical ischemia. Infarct volumes, neurobehavioral deficit and motor deficit were evaluated 24 h after focal cerebral ischemia.ResultsThe expression of BDNF protein increased significantly from 6 h, reaching a plateau at 12 h after the end of EA treatment in the cerebral cortex. Furthermore, SDF-1α, not VEGF, increased singnificantly from 12 h to 48 h after EA stimulation in the plasma. Moreover, EA preconditioning reduced the infarct volume by 43.5% when compared to control mice at 24 h after photothrombotic cortical ischemia. Consistent with a smaller infarct size, EA preconditioning showed prominent improvement of neurological function and motor function such as vestibule-motor function, sensori-motor function and asymmetric forelimb use. The expression of BDNF colocalized within neurons and SDF-1α colocalized within the cerebral vascular endothelium was observed throughout the ischemic cortex by EA.ConclusionsPretreatment with EA increased the production of BDNF and SDF-1α, which elicited protective effects against focal cerebral ischemia. These results suggest a novel mechanism of EA pretreatment-induced tolerance against cerebral ischemic injury.

Effect of 5-aminolevulinic acid-based photodynamic therapy via reactive oxygen species in human cholangiocarcinoma cells

Cancer cells have been reported to exhibit an enhanced capacity for protoporphyrin IX (PpIX) synthesis facilitated by the administration of 5-aminolevulinic acid (ALA). We investigated the effect of ALA-based photodynamic therapy (PDT) on human cholangiocarcinoma cells (HuCC-T1). Since protoporphyrin IX (PpIX), a metabolite of ALA, can produce reactive oxygen species (ROS) under irradiation and then induce phototoxicity, ALA-based PDT is a promising candidate for the treatment of cholangiocarcinoma. When various concentrations of ALA (0.05–2 mM) were used to treat HuCC-T1 cells for 6 or 24 hours, the intracellular PpIX level increased according to the ALA concentration and treatment time. Furthermore, an increased amount of PpIX in HuCC-T1 cells induced increased production of ROS by irradiation, resulting in increased phototoxicity.

Effect of surfactant on 5-aminolevulinic acid uptake and PpIX generation in human cholangiocarcinoma cell.

Photodynamic therapy (PDT) is a palliative therapy and has been used to cure cholangiocarcinoma (CC), which has a poor prognosis and limited available curative therapy. PDT was shown to improve the median survival time of advanced-stage patients. Recently, 5-aminolevulinic acid (ALA) has been used as a pro-photosensitizer, which can be transferred to intercellular protoporphyrin IX (PpIX), which is a strong photosensitizer, via the heme pathway. The main limitation of using ALA in PDT is the hydrophilic properties of ALA, which results in low cellular uptake. In this study, non-ionic surfactants, pluronic F68 (PF68) and Tween 80 (TW80), were used to address this limitation. The human CC cell line, HuCC-T1, was cotreated with ALA and different concentrations of surfactants for 4h. The effect of surfactants was evaluated by monitoring the uptake of ALA, the fluorescence intensity of PpIX, and the cell survival rate after suitable light irradiation. Cotreatment with the surfactant resulted in an increased intracellular ALA level, PpIX formation, and phototoxicity.

Cyanidin-3-rutinoside increases glucose uptake by activating the PI3K/Akt pathway in 3T3-L1 adipocytes.

In this study, the effect of cyanidin-3-rutinoside (C3R) on glucose uptake by 3T3-L1 adipocytes was studied. C3R significantly increased glucose uptake, which was associated with enhanced plasma membrane glucose transporter type 4 (PM-GLUT4) expression in 3T3-L1 adipocytes. The potentiating effect of C3R on glucose uptake and PM-GLUT4 expression was related to enhanced phosphorylation of insulin receptor substrate 1 (IRS-1) and Akt, as well as augmented activation of phosphatidylinositol-3-kinase (PI3K) in the insulin signaling pathway. C3R induced glucose uptake was inhibited only by the PI3K inhibitor, but not by an AMPK inhibitor in 3T3-L1 adipocytes. Therefore, C3R likely up-regulates glucose uptake and PM-GLUT4 expression in 3T3-L1 adipocytes by activating the PI3K/Akt pathways.

Alleviating Effects of Mulberry Fruit Extract on Postprandial Hyperglycemia in Streptozotocin-induced Diabetic Mice

Postprandial hyperglycemia is an early defect of type 2 diabetes and one of primary anti-diabetic targets. The alpha-glucosidase inhibitors regulate postprandial hyperglycemia by impeding the rate of carbohydrate (such as starch) digestion in the small intestine. This study was designed to investigate the inhibitory actions of mulberry fruit extract (MFE) on α-glucosidase and α-amylase activities, and its alleviating effect on postprandial hyperglycemia activities in vitro and in vivo. Male four-week old ICR mice and streptozotocin (STZ)-induced diabetic mice were treated with mulberry fruit extract. MFE showed strong inhibitory effects against α-glucosidase and α-amylase activities, with half-maximal inhibitory concentration (IC50) values of 0.16 and 0.14 mg/ml, respectively, and was more effective than acarbose, which was used as a positive control. The increase in postprandial blood glucose levels was more significantly attenuated in the MFE-administered group mice than in the control group mice of both STZ-induced diabetic and normal mice. Moreover, the area under the glucose response curve significantly decreased following MFE administration in diabetic mice. These results indicate that MFE may be a potent inhibitor of α-glucosidase and α-amylase, and helpful in suppressing postprandial hyperglycemia in diabetic mice. The mulberry fruit extracts may be considered as a potential candidate for the management of diabetes.