The Effects of Busulfan on Xenogeneic Transplantation of Human Peripheral Blood Mononuclear Cells in Recipient Mice.

BACKGROUND: Humanized mouse models with engraftment of human peripheral blood mononuclear cells (PBMCs) or hematopoietic stem cells (HSCs) are effective tools for the study of human immunity. Busulfan has been used as a substitute for irradiation in human hematopoietic stem cell (HSC) transplantation models, but it has not been tested in human peripheral blood mononuclear cell (PBMC) transplantation models. METHODS: This study evaluated PBMC engraftment using cytometry and enzyme-linked immunosorbent assay (ELISA) in female NOD.CB17/Prkdcscid/JKrb/ IL2 receptor γ-/- (NIG) mice treated with busulfan. RESULTS: In this model, the percentage of human CD3+ T cell engraftment in the blood was 28.2%, with dominant infiltration of CD8+ cells in the spleen 3 weeks post PBMC transplantation. Production of human cytokines, including Interleukin (IL)-12p70, IL-4, IL-5, IFN-γ, IL-6, IL-8, IL-22, Tumor Necrosis Factor alpha, and IL-10, was determined in mice treated with busulfan. CONCLUSIONS: Our findings demonstrate that busulfan treatment is a beneficial alternative for simple and efficient PBMC engraftment in a rodent model, possibly helping to evaluate human immunity in preclinical studies.

In vivo genome editing using 244-cis LNPs and low-dose AAV achieves therapeutic threshold in hemophilia A mice.

Gene therapy and rebalancing therapy have emerged as promising approaches for treating hemophilia A, but there are limitations, such as temporary efficacy due to individual differences. Genome editing for hemophilia has shown long-term therapeutic potential in preclinical trials. However, a cautious approach is necessary because genome editing is irreversible. Therefore, we attempted to induce low-level human factor 8 (hF8) gene knockin (KI) using 244-cis lipid nanoparticles and low-dose adeno-associated virus to minimize side effects and achieve a therapeutic threshold in hemophilia A mice. We selected the serpin family C member 1, SerpinC1, locus as a target to enable a combined rebalancing strategy with hF8 KI to augment efficacy. This strategy improved blood coagulation activity and reduced hemophilic complications without adverse effects. Furthermore, hemophilic mice with genome editing exhibit enhanced survival for 40 weeks. Here, we demonstrate an effective, safe, and sustainable treatment for hemophilia A. This study provides valuable information to establish safe and long-term genome-editing-mediated treatment strategies for treating hemophilia and other protein-deficient genetic diseases.

Preclinical Evaluation of interferon-gamma primed human Wharton's jelly-derived mesenchymal stem cells.

The potential of human mesenchymal stem cells (MSCs) for cell therapy has been investigated in numerous immune-mediated conditions; MSCs are considered one of the most promising cellular therapeutics to treat intractable diseases. Recently, approaches to prime MSCs have been investigated, thereby generating cellular products with enhanced potential for a variety of clinical applications. Interferon-gamma (IFN-γ) priming is a current approach used to increase the therapeutic efficacy of MSCs. In this study, we determined the systemic toxicity, tumorigenicity and biodistribution of IFN-γ-primed Wharton's jelly-derived (WJ)-MSCs in male and female BALB/c-nu/nu mice. There were no deaths or pathologic lesions in the mice treated with 5 × 106 cells/kg IFN-γ-primed MSCs in the repeated dose study. In the tumorigenicity study, one of the subcutaneously treated mice showed bronchioloalveolar adenoma in the lung but tested negative for human-specific anti-mitochondrial antibody, suggesting the spontaneous murine origin of the adenoma. A biodistribution study using real-time quantitative polymerase chain reaction demonstrated the systemic IFN-γ-primed MSC clearance by day 28. Based on the toxicity, biodistribution, and tumorigenicity studies, we concluded that IFN-γ-primed MSCs at 5 × 106 cells/kg do not induce tumor formation and adverse changes.

A general toxicity and biodistribution study of human natural killer cells by single or repeated intravenous dose in severe combined immune deficient mice.

Natural killer (NK) cells are a part of the innate immune system and represent the first line of defense against infections and tumors. NK cells can eliminate tumor cells without major histocompatibility restriction and are independent of the expression of tumor-associated antigens. Therefore, they are considered an emerging tool for cancer immunotherapy. However, the general toxicity and biodistribution of NK cells after transplantation remain to be understood. This study was conducted to evaluate the general toxicity and biodistribution of human NK cells after single or repeated intravenous dosing in severely combined immunodeficient (SCID) mice. There were no test item-related toxicological changes in single and repeated administration groups. The no observed adverse effect level of human NK cells was 2 × 107 cells/head for both male and female SCID mice. Results from the biodistribution study showed that human NK cells were mainly distributed in the lungs, and a small number of the cells were detected in the liver, heart, spleen, and kidney of SCID mice, in both the single and repeated dose groups. Additionally, human NK cells were completely eliminated from all organs of the mice in the single dose group on day 7, while the cells persisted in mice in the repeated dose group until day 64. In conclusion, transplantation of human NK cells in SCID mice had no toxic effects. The cells were mainly distributed in the lungs and completely disappeared from the body over time after single or repeated intravenous administration.

Bisphenol A impairs renal function by reducing Na+/K+-ATPase and F-actin expression, kidney tubule formation in vitro and in vivo.

The kidney proximal tubule is responsible for reabsorbing water and NaCl to maintain the homeostasis of the body fluids, electrolytes, and nutrients. Thus, abnormal functioning of the renal proximal tubule can lead to life-threatening imbalances. Bisphenol A (BPA) has been used for decades as a representative chemical in household plastic products, but studies on its effects on the kidney proximal tubule are insufficient. In this study, immunocytochemical and cytotoxicity tests were performed using two- and three-dimensional human renal proximal tubular epithelial cell (hRPTEC) cultures to investigate the impact of low-dose BPA (1-10 µM) exposure. BPA was found to interfere with straight tubule formation as observed by low filamentous actin formation and reduced Na+/K+-ATPase expression in the tubules of hRPTEC 3D cultures. Similar results were observed in rat pup kidneys following oral administration of 250 mg/kg BPA. Moreover, the expression of HO-1 and 8-OHdG, key markers for oxidative stress, was increased in vitro and in vivo following BPA administration, whereas that of OAT1 and OAT, important transporters of the renal proximal tubules, was not altered. Overall, no-observed-adverse-effect-level (NOAEL)-dose BPA exposure can decrease renal function by promoting abnormal tubular formation both in vitro and in vivo. Therefore, we propose that although it does not exhibit life-threatening toxicity, exposure to low levels of BPA can negatively affect homeostasis in the body by means of long-term deterioration of renal proximal tubular function in humans.

Tumorigenicity Assessment of Human Cancer Cell Lines Xenografted on Immunodeficient Mice as Positive Controls of Tumorigenicity Testing.

Recent advances in human pluripotent stem cell (hPSC)-derived cell therapies and genome editing technologies such as CRISPR/Cas9 make regenerative medicines promising for curing diseases previously thought to be incurable. However, the possibility of off-target effects during genome editing and the nature of hPSCs, which can differentiate into any cell type and infinitely proliferate, inevitably raises concerns about tumorigenicity. Tumorigenicity acts as a major obstacle to the application of hPSC-derived and gene therapy products in clinical practice. Thus, regulatory authorities demand mandatory tumorigenicity testing as a key pre-clinical safety step for the products. In the tumorigenicity testing, regulatory guidelines request to include human cancer cell line injected positive control group (PC) animals, which must form tumors. As the validity of the whole test is determined by the tumor-forming rates (typically above 90%) of PC animals, establishing the stable tumorigenic condition of PC animals is critical for successful testing. We conducted several studies to establish the proper positive control conditions, including dose, administration routes, and the selection of cell lines, in compliance with Good Laboratory Practice (GLP) regulations and/or guidelines, which are essential for pre-clinical safety tests of therapeutic materials. We expect that our findings provide insights and practical information to create a successful tumorigenicity test and its guidelines.

Characteristics of Extracellular Vesicles and Preclinical Testing Considerations Prior to Clinical Applications.

Cell therapy products have significant limitations, such as storage instability, difficulties with transportation, and toxicity issues such as tumorigenicity and immunogenicity. Extracellular vesicles (EVs) secreted from cells show potential for therapeutic agent development. EVs have not been widely examined as investigational drugs, and non-clinical studies for the clinical approval of EV therapeutic agents are challenging. EVs contain various materials, such as DNA, cellular RNA, cytokines, chemokines, and microRNAs, but do not proliferate or divide like cells, thus avoiding safety concerns related to tumorigenicity. However, the constituents of EVs may induce the proliferation of normal cells; therefore, the suitability of vesicles should be verified through non-clinical safety evaluations. In this review, the findings of non-clinical studies on EVs are summarized. We describe non-clinical toxicity studies of EVs, which should be useful for researchers who aim to develop these vesicles into therapeutic agents. A new method for evaluating the immunotoxicity and tumorigenicity of EVs should also be developed.

Biomarker LEPRE1 induces pelitinib-specific drug responsiveness by regulating ABCG2 expression and tumor transition states in human leukemia and lung cancer.

Biomarkers for treatment sensitivity or drug resistance used in precision medicine include prognostic and predictive molecules, critical factors in selecting appropriate treatment protocols and improving survival rates. However, identification of accurate biomarkers remain challenging due to the high risk of false-positive findings and lack of functional validation results for each biomarker. Here, we discovered a mechanical correlation between leucine proline-enriched proteoglycan 1 (LEPRE1) and pelitinib drug sensitivity using in silico statistical methods and confirmed the correlation in acute myeloid leukemia (AML) and A549 lung cancer cells. We determined that high LEPRE1 levels induce protein kinase B activation, overexpression of ATP-binding cassette superfamily G member 2 (ABCG2) and E-cadherin, and cell colonization, resulting in a cancer stem cell-like phenotype. Sensitivity to pelitinib increases in LEPRE1-overexpressing cells due to the reversing effect of ABCG2 upregulation. LEPRE1 silencing induces pelitinib resistance and promotes epithelial-to-mesenchymal transition through actin rearrangement via a series of Src/ERK/cofilin cascades. The in silico results identified a mechanistic relationship between LEPRE1 and pelitinib drug sensitivity, confirmed in two cancer types. This study demonstrates the potential of LEPRE1 as a biomarker in cancer through in-silico prediction and in vitro experiments supporting the clinical development of personalized medicine strategies based on bioinformatics findings.

Preclinical safety assessment of a therapeutic human papillomavirus DNA vaccine combined with intravaginal interleukin-7 fused with hybrid Fc in female rats.

This study was conducted to establish the toxicological profile of combination treatment with therapeutic HPV DNA vaccines (GX-188E) and the long-acting form of recombinant human interleukin-7 fused with hybrid Fc (IL-7hyFc). GX-188E was administered intramuscularly by electroporation with or without IL-7hyFc intravaginally once per 2 weeks for 8 weeks (five times) in female Sprague-Dawley rats. Because up-regulation of immune responses and migration of antigen-specific T cells in cervicoviginal tissue were predicted as therapeutic effects, we distinguished adverse effects from therapeutic effects based on the severity of the systemic immune response, reversibility of lymphoid tissue changes, target tissue damage, and off-target immune responses. We observed that the number of neutrophils was increased, and the number of lymphocytes was decreased in the blood. Further, myofiber degeneration, necrosis, fibroplasia, and cell infiltration were observed at the GX-188E administration site. These changes were fully or partially recovered over a 4-week period. Analysis of lymphocytes in spleen revealed that CD4+ T cells and total T cells decreased in rats treated with GX-188E in combination with a high dose of IL-7hyFc (1.25 mg/animal). However, these changes were not considered adverse because they were transient and may have been related to electroporation-mediated DNA delivery or the local migration of lymphocytes induced by IL-7. Therefore, the potential toxicity of the combination of GX-188E and IL-7hyFc treatment was comparable to that of GX-188E treatment alone, and the no observed adverse effect level for GX-188E with IL-7hyFc was considered as 320 µg/animal for GX-188E and 1.25 mg/animal for IL-7hyFc.

In vitro and in vivo assessment of the genotoxic effects of ceric ammonium nitrate and 1,3-propane sultone.

A variety of methods have been developed for accurate and systematic evaluation of chemical genotoxicity. Ceric ammonium nitrate (CAN) and 1,3-propane sultone (1,3-PS) have been extensively applied in industrial fields. Although 1,3-PS, but not CAN, has been reported as a potent carcinogen, systematic assessment of the genotoxic properties of these chemicals has not been conducted. The purpose of this study was to establish a decision tree for evaluating genotoxicity based on the good laboratory practices (GLP) system using 1,3-PS and CAN as test chemicals. In vitro studies were performed including the bacterial reverse mutation assay, chromosomal aberration assay, and micronucleus assay. We conducted in vivo studies using a combined micronucleus and alkaline comet (MN-CMT) assay and the Pig-a gene mutation assay, which is a promising method for detecting gene mutations in vivo. CAN showed negative responses in all in vitro genotoxicity assays and the in vivo combined MN-CMT assay. Meanwhile, 1,3-PS had positive results in all in vitro and in vivo genotoxicity assays. In this study, we confirmed the genotoxicity of 1,3-PS and CAN using both in vitro and in vivo assays. We propose a decision tree for evaluating chemical-induced genotoxicity.

Subacute toxicity and toxicokinetics study of DHP107, an oral paclitaxel formulation with once-weekly dosing in mice.

DHP107, an oral formulation of paclitaxel, is effectively and systemically absorbed in intestinal endothelial cells. Although the in vivo efficacy of DHP107 has been reported, the potential toxicity of DHP107 has not been evaluated. Therefore, this study was conducted to evaluate the toxicity and toxicokinetics of DHP107 orally administered to ICR mice at 25, 50, and 100 mg/kg via once-weekly dosing for six weeks. DHP107-related clinical signs were observed in both sexes at 100 mg/kg. There were significant increases in the number of platelets and percentages of reticulocytes and basophils in male mice. Also in males, there was a significant decrease in the absolute and relative weights of testes, epididymides, kidneys, and heart. Relative spleen weights were significantly increased in males treated with doses ≥50 mg/kg which had histopathological correlates. These changes were reversible after a two-week recovery period with the exception of the findings in the reproductive organs. Systemic exposure to paclitaxel increased with DHP107 doses in single and multiple dosing with no marked differences between sexes. In conclusion, the target organs were determined to be the reproductive and hematopoietic organs in male mice, suggesting of sex difference and the NOAEL of DHP107 was established to be < 25 mg/kg for males and 50 mg/kg for females.

Therapeutic Effect of a Xeno-Free Three-Dimensional Stem Cell Mass in a Hind Limb Ischemia Model.

IMPACT STATEMENT: We describe an innovative method of culturing a three-dimensional cell mass (3DCM) of human adipose-derived stem cells (hASCs) in the xeno-free (XF) condition for the treatment of severe ischemic diseases. The majority of the mice injected with XF-3DCMs exhibited limb salvaging and displayed similar blood perfusion compared to normal limbs. In vivo tumorigenicity and toxicity analysis showed that XF-3DCMs did not transform into tumor cells and induce toxicity, respectively. Our results strongly suggest that XF-3DCMs can be effectively used for therapeutic applications and eliminate immunological reaction of animal-derived material contamination.

Subchronic oral toxicity study of Korean red ginseng extract in Sprague-Dawley rats with a 4-week recovery period.

Ginseng is a major herbal remedy used in Asian countries for thousands of years and known to restore and enhance vital energy. Korean red ginseng, which is processed by steaming and drying fresh Panax ginseng, is most popular and contains unique ginsenosides, which have anticancer and anti-inflammatory properties. The present study was carried out to evaluate the repeated oral dose toxicity of Korean red ginseng extract. The test article was administered orally once a day to male and female Sprague-Dawley rats at dose levels of 0, 500, 1000, or 2000 mg/kg/day for 13 consecutive weeks (15 animals/sex/group in the vehicle control and 2000 mg/kg/day groups, and 10 animals/sex/group in the 500 and 1000 mg/kg/day groups). Ten animals per group were sacrificed at the end of the 13-week treatment period, and the remaining rats were sacrificed after a 4-week recovery period. Administration of Korean red ginseng extract did not result in any toxicologically significant changes in mortality, body weight, food consumption, ophthalmoscopy, hematology, serum biochemistry, gross pathological findings, absolute/relative organ weights, or histopathology. It was established that the no observed adverse effect level (NOAEL) of the test article was 2000 mg/kg/day for both sexes in this study.

Twenty-six-week oral carcinogenicity study of 3-monochloropropane-1,2-diol in CB6F1-rasH2 transgenic mice.

The carcinogenic potential of 3-monochloro-1,2-propanediol (3-MCPD) was evaluated in a short-term carcinogenicity testing study using CB6F1 rasH2-Tg (rasH2-Tg) mice. 3-MCPD is found in many foods and food ingredients as a result of storage or processing and is regarded as a carcinogen since it is known to induce Leydig cell and kidney tumors in rats. Male and female rasH2-Tg mice were administered 3-MCPD once daily by oral gavage at doses of 0, 10, 20, and 40 mg/kg body weight (bw) per day for 26 weeks. As a positive control, N-methyl-N-nitrosourea (MNU) was administered as a single intraperitoneal injection (75 mg/kg). In 3-MCPD-treated mice, there was no increase in the incidence of neoplastic lesions compared to the incidence in vehicle control mice. However, 3-MCPD treatment resulted in an increased incidence of tubular basophilia in the kidneys and germ cell degeneration in the testes, with degenerative germ cell debris in the epididymides of males at 20 and 40 mg/kg bw per day. In 3-MCPD-treated females, vacuolation of the brain and spinal cord was observed at 40 mg/kg bw per day; however, only one incidence of vacuolation was observed in males. Forestomach and cutaneous papilloma and/or carcinoma and lymphoma were observed in most rasH2 mice receiving MNU treatment. We concluded that 3-MCPD did not show carcinogenic potential in the present study using rasH2-Tg mice. The findings of this study suggest that the carcinogenic potential of 3-MCPD is species specific.

Potential urinary biomarkers of nephrotoxicity in cyclophosphamide-treated rats investigated by NMR-based metabolic profiling.

The anticancer-drug cyclophosphamide (CP) is known to have nephrotoxicity. The aim of this study was to identify urinary biomarkers indicating CP-induced nephrotoxicity. We investigated the urine metabolic profiles using nuclear magnetic resonance spectrometry of rats administered with single high-doses of CP (0, 30, and 100 mg/kg body weight) and daily low-doses over a 4-week period (0, 1, 3, and 10 mg/kg body weight). Among 18 identified urinary metabolites, 2-oxoglutarate, citrate, hippurate, formate, valine, and alanine for short-term and 2-oxoglutarate, citrate, hippurate, isoleucine, leucine, allantoin, valine, and lysine for long-term were selected as potential biomarkers. Pathway-enrichment analysis suggested that the urinary metabolism of CP is related to valine, leucine, and isoleucine biosynthesis; taurine and hypotaurine metabolism; glyoxylate and dicarboxylate metabolism; citrate cycle; and alanine, aspartate, and glutamate metabolism, with high pathway impact. The potential biomarkers obtained in this study could be used to monitor CP-induced nephrotoxicity relative to dose and treatment time.

Tumorigenicity Evaluation of Umbilical Cord Blood-derived Mesenchymal Stem Cells.

Mesenchymal stem cells (MSCs) have been identified in multiple types of tissue and exhibit characteristic self-renewal and multi-lineage differentiation abilities. However, the possibility of oncogenic transformation after transplantation is concerning. In this study, we investigated the tumorigenic potential of umbilical cord blood-derived MSCs (hUCB-MSCs) relative to MRC-5 and HeLa cells (negative and positive controls, respectively) both in vitro and in vivo. To evaluate tumorigenicity in vitro, anchorage-independent growth was assessed using the soft agar colony formation assay. hUCB-MSCs and MRC-5 cells formed few colonies, while HeLa cells formed a greater number of larger colonies, indicating that hUCB-MSCs and MRC-5 cells do not have anchorage-independent proliferation potential. To detect tumorigenicity in vivo, hUCB-MSCs were implanted as a single subcutaneous injection into BALB/c-nu mice. No tumor formation was observed in mice transplanted with hUCB-MSCs or MRC-5 cells based on macroand microscopic examinations; however, all mice transplanted with HeLa cells developed tumors that stained positive for a human gene according to immunohistochemical analysis. In conclusion, hUCB-MSCs do not exhibit tumorigenic potential based on in vitro and in vivo assays under our experimental conditions, providing further evidence of their safety for clinical applications.

Characterization of urinary metabolites as biomarkers of colistin-induced nephrotoxicity in rats by a liquid chromatography/mass spectrometry-based metabolomics approach.

Colistin is a polypeptide antibiotic that effectively treats infections caused by multidrug-resistant Gram-negative bacteria, but its clinical use is limited due to nephrotoxicity. The purpose of the present study was to identify biomarkers of colistin-induced nephrotoxicity and to further characterize the mechanisms underlying this process by analyzing urinary metabolites using untargeted metabolomic approach. Rats receiving intraperitoneal administration of colistin sodium methanesulfonate (CMS) (25 or 50mg/kg) exhibited histopathological changes in the kidney and increased blood urea nitrogen levels. Additionally, the levels of phenylalanine, tryptophan, and tyrosine in the urine of the CMS-treated group were significantly higher than those of the control group, suggesting that colistin caused proximal tubular damage. Urinary acetylcarnitine and butyrylcarnitine levels also increased after CMS treatment, but the levels of purine metabolites and metabolites related to the tricarboxylic acid cycle were reduced. The most significant increase in the CMS-treated groups was observed in creatine levels. CMS-induced selective nephrotoxicity may be attributed to relatively high tissue concentrations of colistin in the kidney. Taken together, our results indicate that high levels of colistin in the kidney caused perturbations in the tricarboxylic acid cycle, amino acid metabolism, creatine metabolism, and purine metabolism and ultimately led to kidney injury.

A 28-day oral gavage toxicity study of 3-monochloropropane-1,2-diol (3-MCPD) in CB6F1-non-Tg rasH2 mice.

3-Monochloro-1,2-propanediol (3-MCPD) is a well-known contaminant of foods containing hydrolyzed vegetable protein. However, limited toxicity data are available for the risk assessment of 3-MCPD and its carcinogenic potential is controversial. To evaluate the potential toxicity and determine the dose levels for a 26-week carcinogenicity test using Tg rasH2 mice, 3-MCPD was administered once daily by oral gavage at doses of 0, 25, 50, and 100 mg/kg body weight (b.w.)/day for 28 days to male and female CB6F1-non-Tg rasH2 mice (N = 5 males and females per dose). The standard toxicological evaluations were conducted during the in-life and post-mortem phase. In the 100 mg/kg b.w./day group, 3 males and 1 female died during the study and showed clinical signs such as thin appearance and subdued behavior accompanied by significant decreases in mean b.w. Microscopy revealed tubular basophilia in the kidneys, exfoliated degenerative germ cells in the lumen of the seminiferous tubule of the testes, vacuolation in the brain, axonal degeneration of the sciatic nerve, and cardiomyopathy in the 100, ≥25, ≥50, 100, and 100 mg/kg b.w./day groups, respectively. In conclusion, 3-MCPD's target organs were the kidneys, testes, brain, sciatic nerve, and heart. The "no-observed-adverse-effect level" (NOAEL) of 3-MCPD was ≤25 and 25 mg/kg b.w./day in males and females, respectively.

CKD-501, a novel selective PPARγ agonist, shows no carcinogenic potential in ICR mice following oral administration for 104 weeks.

CKD-501 is a peroxisome proliferator-activated receptor gamma (PPARγ) agonist that is effective for the treatment of diabetes. However, its carcinogenic potential remains controversial. The current carcinogenicity study was conducted over a period of 104 weeks in ICR mice. Three groups, each consisting of 60 male and 60 female mice, received oral CKD-501 dosages of 0.2, 1.0 or 6.0 mg kg(-1) day(-1). The mortality rates of the male control, 0.2, 1.0 and 6.0 mg kg(-1) day(-1) treated groups were 60%, 68%, 58% and 67%, respectively and 57%, 68% and 67% in the female control, 0.2 and 1.0 mg kg(-1) day(-1) treated groups. It was 67% in the female 6.0 mg kg(-1) day(-1) treated group, which was terminated at week 98 due to its increased mortality rate. No significant treatment-related effects were observed on the survival rates, with the exception of females in the 6.0 mg kg(-1) day(-1) group. Body weights increased in females receiving 1.0 and 6.0 mg kg(-1) day(-1) due to the class effects of the PPARγ agonist. Differences were not found in hematology parameters between the CKD-501-treated groups and their corresponding controls, but the histopathological evidence did not reveal any findings attributed to CKD-501. Treated animals exhibited non-neoplastic findings (adipocyte proliferation, bone marrow hypoplasia cardiomyopathy), but all of these were expected changes for this class of compound. There were no treatment-related neoplastic changes in this study. The results of this study therefore demonstrate a lack of carcinogenicity following oral administration of CKD-501 to ICR mice for 104 weeks.

Pathological features of bone marrow transplantation-related toxicity in a mouse.

In this case report, we present a mock-transduced bone marrow (BM) transplantation in a mouse, which was found moribund and autopsied to evaluate pathogenesis. Macroscopically, red discoloration of systemic organs was observed. Hematological values revealed a decrease in white blood cells, red blood cells, hematocrit, hemoglobin, and platelets, but an increase in reticulocytes. In BM cytology, hematopoietic cell lines were severely depleted. Histopathologically, hemorrhage in the cerebellar parenchyma, hemosiderin deposition and hemorrhage in the heart, necrosis and telangiectasia in liver, pulmonary parenchymal cysts, spermatogenic germ cells necrosis, atrophy and hemorrhage in testis, oligospermia and hemorrhage in the epididymis, and atrophy of BM, thymus and spleen were observed. In conclusion, autoimmune-like complications such as hematological value change, BM dysplasia and systemic hemorrhage appear to be the lethal cause of the mouse transplanted with mock-transduced BM.