Goeun Yang

Human neural stem cells over-expressing choline acetyltransferase restore cognition in rat model of cognitive dysfunction.

A human neural stem cell (NSC) line over-expressing human choline acetyltransferase (ChAT) gene was generated and these F3.ChAT NSCs were transplanted into the brain of rat Alzheimer disease (AD) model which was induced by application of ethylcholine mustard aziridinium ion (AF64A) that specifically denatures cholinergic nerves and thereby leads to memory deficit as a salient feature of AD. Transplantation of F3.ChAT human NSCs fully recovered the learning and memory function of AF64A animals, and induced elevated levels of acetylcholine (ACh) in cerebrospinal fluid (CSF). Transplanted F3.ChAT human NSCs were found to migrate to various brain regions including cerebral cortex, hippocampus, striatum and septum, and differentiated into neurons and astrocytes. The present study demonstrates that brain transplantation of human NSCs over-expressing ChAT ameliorates complex learning and memory deficits in AF64A-cholinotoxin-induced AD rat model.

Improvement of cognitive function and physical activity of aging mice by human neural stem cells over-expressing choline acetyltransferase

Aging is characterized by progressive loss of cognitive and memory functions as well as decrease in physical activities. In the present study, a human neural stem cell line (F3 NSC) over-expressing choline acetyltransferase (F3.ChAT), an enzyme responsible for acetylcholine synthesis, was generated and transplanted in the brain of 18-month-old male ICR mice. Four weeks post-transplantation, neurobehavioral functions, expression of ChAT enzyme, production of acetylcholine and neurotrophic factors, and expression of cholinergic nervous system markers in transplanted animals were investigated. F3.ChAT NSCs markedly improved both the cognitive function and physical activity of aging animals, in parallel with the elevation of brain acetylcholine level. Transplanted F3 and F3.ChAT cells were found to differentiate into neurons and astrocytes, and to produce ChAT proteins. Transplantation of the stem cells increased brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF), enhanced expression of Trk B, and restored host microtubule-associated protein 2 and cholinergic nervous system. The results demonstrate that human NSCs over-expressing ChAT improve cognitive function and physical activity of aging mice, not only by producing ACh directly but also by restoring cholinergic neuronal integrity, which might be mediated by neurotrophins BDNF and NGF.

Human adipose tissue-derived mesenchymal stem cells improve cognitive function and physical activity in ageing mice

Brain ageing leads to atrophy and degeneration of the cholinergic nervous system, resulting in profound neurobehavioral and cognitive dysfunction from decreased acetylcholine biosynthesis and reduced secretion of growth and neurotrophic factors. Human adipose tissue‐derived mesenchymal stem cells (ADMSCs) were intravenously (1 × 106 cells) or intracerebroventricularly (4 × 105 cells) transplanted into the brains of 18‐month‐old mice once or four times at 2‐week intervals. Transplantation of ADMSCs improved both locomotor activity and cognitive function in the aged animals, in parallel with recovery of acetylcholine levels in brain tissues. Transplanted cells differentiated into neurons and, in part, into astrocytes and produced choline acetyltransferase proteins. Transplantation of ADMSCs restored microtubule‐associated protein 2 in brain tissue and enhanced Trk B expression and the concentrations of brain‐derived neurotrophic factor and nerve growth factor. These results indicate that human ADMSCs differentiate into neural cells in the brain microenvironment and can restore physical and cognitive functions of aged mice not only by increasing acetylcholine synthesis but also by restoring neuronal integrity that may be mediated by growth/neurotrophic factors.

Immunopotentiation and antitumor effects of a ginsenoside Rg3-fortified red ginseng preparation in mice bearing H460 lung cancer cells

Antitumor effects of a ginsenoside Rg(3)-fortified red ginseng preparation (Rg(3)-RGP) were investigated in human non-small cell lung carcinoma (H460) cells using in vitro cytotoxicity assay and in vivo nude mouse xenograft model. Immunomodulatory effects of the preparation were also assessed by measuring the facilitating activities on the nitric oxide (NO) release from peritoneal macrophages, in vitro and in vivo lymphocyte proliferation, and the carbon clearance from circulating blood. In a cell level, Rg(3)-RGP exerted H460 cytotoxicity and facilitated splenocyte proliferation at very high concentrations, without affecting NO production. However, oral administration of Rg(3)-RGP (100-300 mg/kg) enhanced carbon particle-phagocytic index of blood macrophages up to 360-397% of control value. In addition, Rg(3)-RGP significantly increased the splenocyte proliferation (23% at 100mg/kg). In tumor-bearing mice, 28-day oral treatment with Rg(3)-RGP (100mg/kg) remarkably suppressed the tumor growth, leading to the decrease of the tumor volume and weight by 30-31%, which was comparable to the effect (27-29% reduction) of doxorubicin (2mg/kg at 3-day intervals). While Rg(3)-RGP did not cause adverse effects, intravenous injection of doxorubicin markedly decreased body and testes weights, and exhibited severe depletion of spermatogenic cells in the atrophic seminiferous tubules. These results indicate that Rg(3)-RGP exerts antitumor activities via indirect immunomodulatory actions, without causing adverse effects as seen in doxorubicin.

Animal models of periventricular leukomalacia.

Periventricular leukomalacia, specifically characterized as white matter injury, in neonates is strongly associated with the damage of pre-myelinating oligodendrocytes. Clinical data suggest that hypoxia-ischemia during delivery and intrauterine or neonatal infection-inflammation are important factors in the etiology of periventricular leukomalacia including cerebral palsy, a serious case exhibiting neurobehavioral deficits of periventricular leukomalacia. In order to explore the pathophysiological mechanisms of white matter injury and to better understand how infectious agents may affect the vulnerability of the immature brain to injury, novel animal models have been developed using hypoperfusion, microbes or bacterial products (lipopolysaccharide) and excitotoxins. Such efforts have developed rat models that produce predominantly white matter lesions by adopting combined hypoxia-ischemia technique on postnatal days 1-7, in which unilateral or bilateral carotid arteries of animals are occluded (ischemia) followed by 1-2 hour exposure to 6-8% oxygen environment (hypoxia). Furthermore, low doses of lipopolysaccharide that by themselves have no adverse-effects in 7-day-old rats, dramatically increase brain injury to hypoxic-ischemic challenge, implying that inflammation sensitizes the immature central nervous system. Therefore, among numerous models of periventricular leukomalacia, combination of hypoxia-ischemia-lipopolysaccharide might be one of the most-acceptable rodent models to induce extensive white matter injury and ensuing neurobehavioral deficits for the evaluation of candidate therapeutics.

Increased Nephrotoxicity after Combined Administration of Melamine and Cyanuric Acid in Rats

Renal toxicity by melamine in combination with cyanuric acid (1:1) was investigated. Male rats were orally administered melamine plus cyanuric acid (5, 50 or 400 mg/kg each) for 3 days. In contrast to a negligible effect by melamine alone (50 mg/kg, a no-observed-adverse-effect-level: NOAEL), co-administration with cyanuric acid markedly increased the concentrations of blood urea nitrogen and creatinine, as well as kidney weight. A high dose (400 mg/kg) of melamine plus cyanuric acid induced more severe kidney toxicity. The increased blood parameters for kidney toxicity and organ weight lasted longer than 4 days. Combined treatment with melamine and cyanuric acid (50-400 mg/kg each) resulted in many gold-brown crystals and toxic lesions in renal tubules, which were not observed in animals treated with melamine alone (50 mg/kg). These results indicate that only a 3-day exposure to melamine in combination with cyanuric acid causes severe renal damage, even at a NOAEL for melamine found in a 13-week toxicity study. Therefore, it is suggested that the tolerable daily intake or regulatory/management levels of melamine need to be re-considered for cases of co-exposure with cyanuric acid.

Anti-Helicobacter pylori effects of IgY from egg york of immunized hens

Effects of egg york containing IgY specific for Helicobacter pylori on the bacterial growth and intragastric infection were investigated in comparison with a proton-pump inhibitor pantoprazole. For in vitro anti-bacterial activity test, H. pylori (1×108 CFU/mL) was incubated with a serially diluted IgY for 3 days. As a result, IgY fully inhibited the bacterial growth at 16 mg/mL, which was determined to a minimal inhibitory concentration. In vivo elimination study, male C57BL/6 mice were infected with the bacteria by intragastric inoculation (1×108 CFU/mouse) 3 times at 2-day intervals, and 2 weeks later, orally treated twice a day with 50, 100, 200 or 500 mg/kg IgY for 18 days. After the final administration, biopsy sample of the gastric mucosa was assayed for the bacterial identification via urease, oxidase, catalase, nitrate reduction and H2S tests in addition to microscopic examination for mucosal inflammation. In CLO kit test, 75, 50, 12.5 and 12.5% of the animals revealed positive reaction following treatment with 50, 100, 200 and 500 mg/kg IgY, respectively, resulting in a superior efficacy at 200 mg/kg than 30 mg/kg pantoprazole that displayed 75% elimination. The CLO test results were confirmed by bacterial identification. Microscopic examination revealed that H. pylori infection caused severe gastric mucosal inflammation, which were not observed in the CLO-negative mice following treatment with IgY or pantoprazole. Taken together, IgY inhibited the growth of H. pylori, and improved gastritis and villi injuries by eliminating the bacteria from the stomach. The results indicate that IgY could be a good candidate overcoming tolerance of antibiotics for the treatment of H. pylori-mediated gastric ulcers.

Comparative Effects of Human Neural Stem Cells and Oligodendrocyte Progenitor Cells on the Neurobehavioral Disorders of Experimental Autoimmune Encephalomyelitis Mice

Since multiple sclerosis (MS) is featured with widespread demyelination caused by autoimmune response, we investigated the recovery effects of F3.olig2 progenitors, established by transducing human neural stem cells (F3 NSCs) with Olig2 transcription factor, in myelin oligodendrocyte glycoprotein- (MOG-) induced experimental autoimmune encephalomyelitis (EAE) model mice. Six days after EAE induction, F3 or F3.olig2 cells (1 × 106/mouse) were intravenously transplanted. MOG-injected mice displayed severe neurobehavioral deficits which were remarkably attenuated and restored by cell transplantation, in which F3.olig2 cells were superior to its parental F3 cells. Transplanted cells migrated to the injured spinal cord, matured to oligodendrocytes, and produced myelin basic proteins (MBP). The F3.olig2 cells expressed growth and neurotrophic factors including brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), ciliary neurotrophic factor (CNTF), and leukemia inhibitory factor (LIF). In addition, the transplanted cells markedly attenuated inflammatory cell infiltration, reduced cytokine levels in the spinal cord and lymph nodes, and protected host myelins. The results indicate that F3.olig2 cells restore neurobehavioral symptoms of EAE mice by regulating autoimmune inflammatory responses as well as by stimulating remyelination and that F3.olig2 progenitors could be a candidate for the cell therapy of demyelinating diseases including MS.

Neuroprotective Effects of a Butanol Fraction of Rosa hybrida Petals in a Middle Cerebral Artery Occlusion Model.

The neuroprotective effects of a butanol fraction of white rose petal extract (WRPE-BF) were investigated in a middle cerebral artery occlusion (MCAO) model. Seven week-old male rats were orally administered WRPE-BF for 2 weeks and subjected to MCAO for 2 h, followed by reperfusion. Twenty-four h later, MCAO-induced behavioral dysfunctions were markedly improved in a dose-dependent manner by pretreatment with WRPE-BF. Moreover, higher dose of WRPE-BF not only decreased infarction area but also effectively reduced astrogliosis. The expression of inducible nitric oxide synthase, cyclooxygenase-2, and glial fibrillary acidic protein in MCAO model were markedly inhibited by WRPE-BF treatment. Notably, WRPE-BF decreased nitric oxide and malondialdehyde levels in the striatum and subventricular zone of stroke-challenged brains. These data suggested that WRPE-BF may exert its neuroprotective effects via anti-oxidative and anti-inflammatory activities against ischemia-reperfusion brain injury and could be a good candidate as a therapeutic target for ischemic stroke.

Neurobehavioural deficits correlate with the cerebral infarction volume of stroke animals: A comparative study on ischaemia-reperfusion and photothrombosis models

The study investigated the correlation between infarction areas and behavioural deficits in middle cerebral artery occlusion (MCAO) and photothrombosis stroke models. In the MCAO model, a 0.38 mm-diameter silicone-coated thread was introduced through the left external carotid artery and advanced 18 mm via the internal carotid artery to the origin of middle cerebral artery of male Sprague-Dawley rats weighing 300-350 g. The thread was removed for reperfusion after occlusion for 0.5, 1 or 2h. In the photothrombosis model, after a midline incision on the scalp, a focused light (10,000 lux, 6 mm-diameter) was delivered 1mm anterior to the bregma and 3mm left of the midline for 5, 10 or 20 min. During the first 2 min of irradiation, Rose Bengal dye (30 mg/kg) was injected intravenously. Twenty four hours post-surgery, the animals were subjected to neurological scoring and behavioural performances, and were sacrificed for macroscopic and microscopic examinations of brain injury. Total infarction volumes in the MCAO model rats increased in an occlusion time-dependent manner, while the infarction volumes in photothrombosis model rats plateaued relatively quickly with no time-dependent increase. The MCAO model displayed neurological scores and behavioural deficits that correlated well with infarction volumes, while relatively poor correlation between infarction volume and neurobehavioural abnormalities was evident in the photothrombosis model. The results indicate the suitability of the MCAO model for studies on preventive or therapeutic compounds related to functional recovery, although the photothrombosis model might be useful to generate focused lesions leading to the location-related behavioural changes.