Preclinical safety assessment of Angelica acutiloba using a 13-week repeated dose oral toxicity study in rats / 한국실험동물학회지

Angelica acutiloba (AA), a Japanese species of Danggui, has been used worldwide as a traditional herbal medicine with several bioactivities including anti-diabetic, anti-allergic, anti-inflammatory, anti-tumor, and anti-obesity. However, there is lack of toxicological data available to evaluate potential long-term toxicity and the no-observed-adverse-effect level (NOAEL) of AA extract in accordance with the test guidelines published by the Organization for Economic Cooperation and Development. In the 14-day repeat-dose toxicity study, no adverse effects on mortality, body weight change, clinical signs, and organ weights was found following repeat oral administration to rats for 14 days (125, 250, 500, 1000, and 2000 mg/kg body weight), leading that 2000 mg/kg is the highest recommended dose of AA extract for the 13-week repeat-dose oral toxicity study. In the 13-week repeat-dose oral toxicity study, the AA extract was orally administered to groups of rats for 13 weeks (125, 250, 500, 1000, and 2000 mg/kg body weight) to compare between control and AA extract groups. The administration of AA extract did not produce mortality or remarkable clinical signs during this 13-week study. And, the data revealed that there were no significant differences in food/water consumption, body weight, hematological parameters, clinical chemistry parameters, gross macroscopic findings, organ weight and histopathology in comparison to the control group. On the basis of these results, the subchronic NOAEL of the AA extract was more than 2000 mg/kg/day when tested in rats. And, the AA extract is considered safe to use orally as a traditional herbal medicine.

Evaluation of in vitro and in vivo genotoxicity of Angelica acutiloba in a standard battery of assays / 한국실험동물학회지

Among three representative species of Angelica found in Asian countries, including Korea, China, and Japan, Angelica acutiloba (AA) has been used as traditional herbal medicine with antitumor, anti-inflammatory, anti-obesity, and anti-diabetes activities. In this study, the potential genotoxicity and mutagenicity of the AA extract were examined in a battery of in vitro and in vivo tests (bacterial reverse mutation assay, in vitro chromosomal aberrations assay, and in vivo micronucleus assay) in accordance with the test guidelines for toxicity testing developed by the Organization for Economic Cooperation and Development. Upon testing in the bacterial mutation assay (Ames test) using five Salmonella typhimurium TA98, TA100, TA102, TA1535 and TA1537, no significant increase the number of revertant colonies in the metabolic activation system and non-activation system was noted in the AA extract groups. Also, in the chromosome aberration test, the AA extract did not cause chromosomal aberration with or without metabolic activation by S9 mix. A bone marrow micronucleus test of mice demonstrated that the incidence of micronucleated polychromatic erythrocytes in the AA extract groups (500, 1000 and 2000 mg/kg BW) was equivalent to that of the negative control group. Based on these results from a standard battery of assays, the AA extract was concluded to have no genotoxic at the proper dose.

Bone marrow stem/progenitor cell mobilization in C57BL/6J and BALB/c mice / 한국실험동물학회지

Bone marrow (BM) has been considered as a reservoir of stem/progenitor cells which are able to differentiate into ectodermal, endodermal, and mesodermal origins in vitro as well as in vivo. Following adequate stimulation, such as granulocyte stimulating factor (G-CSF) or AMD3100, BM resident stem/progenitor cells (BMSPCs) can be mobilized to peripheral blood. Several host-related factors are known to participate in this mobilization process. In fact, a significant number of donors are resistant to G-CSF induced mobilization protocols. AMD3100 is currently used in combination with G-CSF. However, information regarding host-related factors which may influence the AMD3100 directed mobilization is extremely limited. In this study, we were to get some more knowledge on the host-related factors that affect the efficiency of AMD3100 induced mobilization by employing in vivo mobilization experiments. As a result, we found that C57BL/6J mice are more sensitive to AMD3100 but less sensitive to G-CSF which promotes the proliferation of BMSPCs. We excluded S1P as one of the host related factor which influences AMD3100 directed mobilization because pre-treatment of S1P receptor antagonist FTY720 did not inhibit BMSPC mobilization. Further in vitro experiments revealed that BALB/c mice, compared to C57BL/6J mice, have less BMSPCs which migrate in response to host related factors such as sphingosine-1-phosphate (S1P) and to CXCL12. We conclude that AMD3100-directed mobilization depends on the number of BMSPCs rather than on the host-related factors. These results suggest that the combination of AMD3100 and G-CSF is co-operative and is optimal for the mobilization of BMSPCs.

The Role of Endothelin Receptor A during Myelination of Developing Oligodendrocytes

Endothelin (ET)-1 and its receptors (ETA and ETB receptor) are present in the central nervous system. ET exerts biological effects on gliogenesis and glial cell functions. In order to define a possible mechanism of ETA receptor signaling, the distribution of the ETA receptor in developing oligodendrocytes and the effects of ET-1 on the myelination of oligodendrocytes were examined. ETA receptor immunoreactivity was confined to the perivascular elements of the blood vessels during early postnatal development. However later in development, ETA receptor immunoreactivity was no longer observed in the vessels but became localized to the myelinating oligodendrocytes of the primitive corpus callosum of the white matter, apart from the vessels. ET-1 induced myelin basic protein (MBP) in primary oligodendrocyte precursor cell culture though the ETA receptor and was blocked by an ETA receptor antagonist. In addition, ET-1 evoked the release of Ca2+ which is a central regulator of oligodendrocyte differentiation. Our results provide a link between ET-1 and its ETA receptor and myelination during oligodendrocyte differentiation.

Establishment of Efficacy and Safety Assessment of Human Adipose Tissue-Derived Mesenchymal Stem Cells (hATMSCs) in a Nude Rat Femoral Segmental Defect Model

Human adipose tissue-derived mesenchymal stem cell (hATMSC) have emerged as a potentially powerful tool for bone repair, but an appropriate evaluation system has not been established. The purpose of this study was to establish a preclinical assessment system to evaluate the efficacy and safety of cell therapies in a nude rat bone defect model. Segmental defects (5 mm) were created in the femoral diaphyses and transplanted with cell media (control), hydroxyapatite/tricalcium phosphate scaffolds (HA/TCP, Group I), hATMSCs (Group II), or three cell-loading density of hATMSC-loaded HA/TCP (Group III-V). Healing response was evaluated by serial radiography, micro-computed tomography and histology at 16 weeks. To address safety-concerns, we conducted a GLP-compliant toxicity study. Scanning electron microscopy studies showed that hATMSCs filled the pores/surfaces of scaffolds in a cell-loading density-dependent manner. We detected significant increases in bone formation in the hATMSC-loaded HA/TCP groups compared with other groups. The amount of new bone formation increased with increases in loaded cell number. In a toxicity study, no significant hATMSC-related changes were found in body weights, clinical signs, hematological/biochemical values, organ weights, or histopathological findings. In conclusion, hATMSCs loaded on HA/TCP enhance the repair of bone defects and was found to be safe under our preclinical efficacy/safety hybrid assessment system.

Granulocyte-Derived Cationic Peptide Enhances Homing and Engraftment of Bone Marrow Stem Cells after Transplantation / 한국실험동물학회지

Current strategies to accelerate hematopoietic reconstitution after transplantation include transplantation of greater numbers of hematopoietic stem/progenitor cells (HSPCs) or ex vivo expansion of harvested HSPCs before transplant. However, the number of cells available for transplantation is usually low, and strategies to expand HSPCs and maintain equivalent engraftment capability ex vivo are limited. We noted that activated granulocyte-derived cationic peptides positively primed responsiveness of HSPCs to a CXCL12 gradient. Accordingly, we noted that accelerated homing/engraftment of beta-defensin-2, a well-known antimicrobial cationic peptide, primed bone marrow nucleated cells (BMNCs) compared to normal BMNCs after transplantation into lethally irradiated recipients. We envision that small cationic peptides, which primarily possess antimicrobial functions and are harmless to mammalian cells, could be applied to prime HSPCs before transplantation. This novel approach would be particularly important in cord blood transplantation, where the number of HSPCs available for transplantation is usually limited.

Safety Evaluation of Human Fibroblasts in Mice: Tumorigenicity, 13-week Toxicity and Distribution Studies / 한국실험동물학회지

Human fibroblasts were developed for cellular therapy with the aim of correcting of depressed scars, but the safety of that in vivo is unclear. In this study, we assessed the safety of human fibroblasts by investigating the tumorigenicity, 13-week toxicity and through distribution studies. In the tumorigenicity test, nude mice were divided into three dosage level treatment groups with a negative/positive control group. At 6 months after intradermal transplantation, all of the treatment groups showed no development of a nodule on the injection sites and organs. Toxicity studies were performed using ICR and BALB/c mice for 13 weeks. The mice were divided into three dosage level treatment groups with a control and a syngeneic group. There was no treatment-related effect on clinical signs, mortality, body weight, food/water consumption, hematology, serum biochemistry, urine, necropsy findings and histopathological findings in any groups. These results suggest that the no-observed-effect level (NOEL) of the human fibroblasts was greater than 7.5x10(7) cells/kg for mice. In the distribution study, groups were treated with fibroblasts labeled with a fluorescent dye (CM-DiI) at low and high doses with a control and a syngeneic group. At 24 hours, a large percentage of the labeled fibroblasts were observed at the dermal layer. At 3 months, fluorescence of the labeled fibroblasts continued to be observed. Other tissues were not detected the fluorescence at any time. These studies demonstrate that the safety of human fibroblasts is reasonable with no toxic effect, no tumorigenicity and retention in the dermis. Our studies define preclinical safety testing standards relevant to the development of cellular therapeutics.

Platynosomum fastosum Infestation in a Domestic Cat in Korea / 한국실험동물학회지

Cat liver fluke (Platynosomum fastosum) was identified upon necropsy of a Felis catus (domestic cat). This trematode has not been reported in domestic cats previously in Korea. Diagnosis of this fluke was made by the presence of eggs in the feces of the cat through the fecal sedimentation method. Flukes in the gallbladder, bile duct, and liver parenchyma were revealed by the necropsy findings. This report describes as the first case of a domestic cat with Platynosomum fastosum in Korea.

Platynosomum fastosum Infestation in a Domestic Cat in Korea / 한국실험동물학회지

Cat liver fluke (Platynosomum fastosum) was identified upon necropsy of a Felis catus (domestic cat). This trematode has not been reported in domestic cats previously in Korea. Diagnosis of this fluke was made by the presence of eggs in the feces of the cat through the fecal sedimentation method. Flukes in the gallbladder, bile duct, and liver parenchyma were revealed by the necropsy findings. This report describes as the first case of a domestic cat with Platynosomum fastosum in Korea.