Publications by authors named "Akira Koibuchi"

3 Publications

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Single- and multiple-dose safety, tolerability, pharmacokinetic, and pharmacodynamic profiles of ASP0367, or bocidelpar sulfate, a novel modulator of peroxisome proliferator-activated receptor delta in healthy adults: Results from a phase 1 study.

Muscle Nerve 2021 Oct 12. Epub 2021 Oct 12.

Parexel International, Baltimore, MD, USA.

Introduction/aims: ASP0367, or bocidelpar sulfate, is an orally administered small molecule that potently and selectively modulates PPARδ to address mitochondrial dysfunction occurring in diseases including primary mitochondrial myopathy and Duchenne muscular dystrophy. Objectives of this first-in-human trial were to evaluate the safety/tolerability, pharmacokinetics, and pharmacodynamics of ASP0367 in healthy participants.

Methods: In this double-blind phase 1 study, adult participants were randomized to single or multiple ascending oral doses of ASP0367 or placebo; study duration was 1 and 14 days, respectively. Pharmacokinetic parameters under fed conditions were also evaluated.

Results: A total of 64 (single dose cohort) and 37 (multiple dose cohort) participants were included. Following single doses of 1-120 mg, ASP0367 was rapidly absorbed with median time to maximum plasma concentration (t ) of 1.50-2.24 hours under fasting conditions; ASP0367 concentrations declined in a multiphasic manner after reaching maximum plasma concentration. Under fed conditions, t was delayed 1.7 hours. Following multiple once-daily doses, mean half-life of ASP0367 10-75 mg ranged from 14.1-17.5 hours; steady state was reached after 4 days. Negligible accumulation was observed following repeated dosing. No participants receiving ASP0367 discontinued treatment, and all treatment-emergent adverse events were mild-to-moderate in severity; none were deemed drug-related. No clinically significant changes were observed on laboratory or electrocardiography evaluations. Treatment- and dose-dependent upregulation of six PPARδ target genes were observed with single and multiple doses of ASP0367.

Discussion: ASP0367, or bocidelpar sulfate, was well tolerated; rapid absorption, roughly dose-proportional bioavailability, and effects on PPARδ target genes were demonstrated in healthy adult participants.
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October 2021

Development of a New Conditionally Immortalized Human Liver Sinusoidal Endothelial Cells.

Biol Pharm Bull 2018 ;41(3):440-444

Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University.

Liver sinusoidal endothelial cells (LSECs), which are specialized endothelial cells that line liver sinusoids, have been reported to participate in a variety of liver functions, such as blood macromolecule clearance and factor VIII production. In addition, LSECs play crucial roles in liver regeneration following acute liver injury, as well as the development and progression of liver diseases or drug-induced hepatotoxicity. However, the molecular mechanisms underlying their roles remain mostly unknown. Therefore, in order to contribute to the clarification of those mechanisms, herein we report on the development of a new immortalized human LSEC (HLSEC) line. To produce this cell line, two immortalized genes were introduced into the primary HLSECs, which eventually resulted in the establishment of the HLSEC/conditionally immortalized, clone-J (HLSEC/ciJ). Consistent with the two-immortalized gene expression, HLSEC/ciJ showed excellent proliferation activity. Additionally, the results of gene expression analyses showed that several LSEC (as well as pan-endothelial) marker mRNAs and proteins were clearly expressed in HLSEC/ciJ. Furthermore, we found that adherence junction proteins were localized at the cell border in the HLSEC/ciJ monolayer, and that the cells exhibited a tube-like structure formation property. Taken together, the results obtained thus far indicate that we have successfully immortalized HLSECs, resulting in creation of HLSEC/ciJ, a cell line that possesses infinite proliferation ability while retaining possession of at least some HLSEC features. We believe that the HLSEC/ciJ have the potential to provide a valuable and unlimited alternative source of HLSECs for use in liver/LSEC physiology/pathophysiology, pharmacology, and toxicology studies.
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August 2018

Characterization of release profile of ornithine carbamoyltransferase from primary rat hepatocytes treated with hepatotoxic drugs: Implications for its unique potential as a drug-induced liver injury biomarker.

Drug Metab Pharmacokinet 2016 Feb 6;31(1):102-105. Epub 2015 Dec 6.

Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba-shi, Chiba 260-8675, Japan.

Ornithine carbamoyltransferase (OCT) is a mitochondrial protein expressed primarily in the liver. It has been shown that, like alanine aminotransferase (ALT), OCT is released from damaged hepatocytes in rats and humans, which has given rise to the possibility that OCT might provide a diagnostic biomarker of various forms of liver damage, including drug-induced liver injury (DILI). However, OCT release characteristics in DILI, as well as their diagnostic advantages, remain elusive. Therefore, this study aimed at clarifying whether and how OCT is released from rat primary hepatocytes in vitro using seven potentially hepatotoxic drugs. The results showed that OCT releases from damaged hepatocytes were observed for all tested drugs, and that those releases were not associated with mitochondrial membrane proteins. It should be underscored that the release dynamics were significantly larger than those of ALT. Furthermore, unlike ALT, the maximum OCT release levels showed differences depending on the drug being tested, suggesting that OCT release was susceptible to toxicity mechanisms. Taken together, these unique release characteristics highlight the possibility that OCT could provide a promising DILI biomarker that might contribute not only to diagnostic accuracy improvements, but also to a better understanding of toxicity types in clinical and drug development settings.
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February 2016