Usefulness of a humanized tricellular static transwell blood-brain barrier model as a microphysiological system for drug development applications. - A case study based on the benchmark evaluations of blood-brain barrier microphysiological system.

Microphysiological system (MPS), a new technology for in vitro testing platforms, have been acknowledged as a strong tool for drug development. In the central nervous system (CNS), the blood‒brain barrier (BBB) limits the permeation of circulating substances from the blood vessels to the brain, thereby protecting the CNS from circulating xenobiotic compounds. At the same time, the BBB hinders drug development by introducing challenges at various stages, such as pharmacokinetics/pharmacodynamics (PK/PD), safety assessment, and efficacy assessment.

[Pharma challenges to adoption of microphysiological system in drug research and development, especially safety assessment].

In the environment surrounding the pharma industries (1) declining productivity in research and development in pharma industries, (2) spreading of 3Rs in animal testing, and (3) diversifying of modalities, the regulatory authorities and pharmaceutical companies in US and EU are paying attention to the microphysiological system (MPS) to actively incorporate cutting-edge technologies into the evaluation assays used for approval applications for drug research and development. MPS generally refers to an in vitro culture system in which a culture environment close to that of a living body (in vivo) is reconstructed in a created minute space using a microfluidic device. Currently, many products have been put into practical use by US and EU companies and are sold all over the world.

Consideration for the validation of clinical laboratory methods in nonclinical fields.

In new drug development, cells or animals are treated with the selected candidate compound to confirm its efficacy and safety in nonclinical studies. Clinical laboratory tests are carried out using samples from experimental animals in these studies. The clinical laboratory test method validation in nonclinical fields should be conducted keeping in mind that the circumstances differ from those in clinical settings.

Progression process and safety assessment adaptation of endometrial lesions in ENU-induced 2-stage uterine carcinogenicity in a Tg-rasH2 mouse model.

Although acotiamide hydrochloride hydrate (acotiamide-HH) has not been reported to have genotoxic findings in any of the genotoxicity studies or treatment-related toxicological findings in reproductive and developmental studies, suspicious uterine tumorigenesis was observed in the results of a long-term rat carcinogenicity study. To clarify the uterine tumorigenesis of acotiamide-HH, we performed a 2-stage uterine carcinogenicity model in the transgenic rasH2 mouse initiated by N-Ethyl-N-nitrosourea (ENU). This model facilitated the short-term detection of uterine carcinogenic potential, and it appears to be a very useful testing method for assessing the safety of chemicals that may affect uterine tumorigenesis.

Investigation of Mechanisms for MK-801-Induced Neurotoxicity Utilizing Metabolomic Approach.

Single treatment of rats with the noncompetitive N-methyl-D-aspartate receptor antagonist MK-801 induces neuronal cell degeneration and death in the retrosplenial/posterior cingulate cortex (RS/PC) region, along with local cerebral glucose utilization. However, the relationship between this neuronal cell degeneration and death and glucose utilization remains unclear. To investigate the mechanism of MK-801-induced neurotoxicity and its relation to glucose utilization, changes in endogenous metabolites in the RS/PC region of MK-801 treated rats were assessed using metabolomics.

Hydroxyproline, a serum biomarker candidate for gastric ulcer in rats: a comparison study of metabolic analysis of gastric ulcer models induced by ethanol, stress, and aspirin.

Gastrointestinal symptoms are a common manifestation of adverse drug effects. Non-steroid anti-inflammatory drugs (NSAIDs) are widely prescribed drugs that induce the serious side effect of gastric mucosal ulceration. Biomarkers for these side effects have not been identified and ulcers are now only detectable by endoscopy.

[18F]FDG-PET as an imaging biomarker to NMDA receptor antagonist-induced neurotoxicity.

Positron emission tomography (PET) is an effective tool for noninvasive examination of the body and provides a range of functional information. PET imaging with [(18)F]fluoro-2-deoxy-d-glucose ([(18)F]FDG) has been used to image alterations in glucose metabolism in brain or cancer tissue in the field of clinical diagnosis but not in the field of toxicology. A single dose of N-methyl-d-aspartate (NMDA) receptor antagonist induces neuronal cell degeneration/death in the rat retrosplenial/posterior cingulate (RS/PC) cortex region.

Metabolic profiling to identify potential serum biomarkers for gastric ulceration induced by nonsteroid anti-inflammatory drugs.

Nonsteroid anti-inflammatory drugs (NSAIDs) are among the most frequently prescribed drugs currently available. The most frequently reported serious side effects associated with NSAIDs are gastric mucosal ulceration and gastric hemorrhage. Presently, these side effects are only detectable by endoscopy, however, and no biomarkers have yet been identified.

[Role of biomarkers in toxicity treatment "metabonomics" as a new biomarker discovery method].

For the treatment of clinical toxicity, investigations to determine the offending substance and rapid treatment are required. Particularly in the case of drug development, the side-effect biomarkers anticipated in a clinical study are based on various toxicological information gleaned from non-clinical studies. In fact, drug development may be discontinued if no biomarkers can be detected using conventional clinical laboratory methodology; therefore, new approaches for finding biomarkers are needed.

Analysis of gender difference of cardiac risk biomarkers using hGH-transgenic mice.

We investigated gender difference in the effects of chronic exposure to human growth hormone (hGH) on cardiac risk biomarkers using transgenic mice with non-pulsatile circulating hGH. Blood plasma was obtained from transgenic and control mice at 8, 12, and 16 weeks of age, and was used for the measurement of hGH and the following cardiac risk biomarkers: total cholesterol (CHO), triglyceride (TG), HDL cholesterol (HDL), LDL cholesterol (LDL), non esterified free fatty acids (NEFA), and lipid peroxides (LPO). The hearts and the livers of transgenic mice were weighed and histopathologically examined, and the results were compared with those of control mice.

Evaluation of H-FABP as a marker of ongoing myocardial damage using hGH transgenic mice.

Background: There are few heart-specific and highly sensitive biomarkers of cardiac disorders in experimental animals. To evaluate ongoing myocardial damage in experimental mice, available and reliable biomarkers are needed. We investigated whether or not heart-type fatty acid-binding protein (H-FABP) is useful as a biomarker for predicting ongoing myocardial disorders, by using CAG/EGFP-WAP/hGH transgenic male mice with heart disease induced by overexpression of human growth hormone (hGH).