Magnitude of Drug–Drug Interactions in Special Populations

The Impact of Baohuoside I on the Metabolism of Tofacitinib in Rats

Purpose

To study the potential drug-drug interactions between tofacitinib and baohuoside I and to provide the scientific basis for rational use of them in clinical practice.

Methods

A total of eighteen Sprague-Dawley rats were randomly divided into three groups: control group, single-dose group (receiving a single dose of 20 mg/kg of baohuoside I), and multi-dose group (receiving multiple doses of baohuoside I for 7 days). On the seventh day, each rat was orally administered with 10 mg/kg of tofacitinib 30 minutes after giving baohuoside I or vehicle. Blood samples were collected and determined using UPLC-MS/MS. In vitro effects of baohuoside I on tofacitinib was investigated in rat liver microsomes (RLMs), as well as the underlying mechanism of inhibition. The semi-inhibitory concentration value (IC50) of baohuoside I was subsequently determined and its inhibitory mechanism against tofacitinib was analyzed. Furthermore, the interactions between baohuoside I, tofacitinib and CYP3A4 were explored using Pymol molecular docking simulation.

Results

The administration of baohuoside I orally has been observed to enhance the area under the concentration-time curve (AUC) of tofacitinib and decrease the clearance (CL). The observed disparity between the single-dose and multi-dose groups was statistically significant. Furthermore, our findings suggest that the impact of baohuoside I on tofacitinib metabolism may be a mixture of non-competitive and competitive inhibition. Baohuoside I exhibit an interaction with arginine (ARG) at position 106 of the CYP3A4 enzyme through hydrogen bonding, positioning itself closer to the site of action compared to tofacitinib.

Conclusion

Our study has demonstrated the presence of drug-drug interactions between baohuoside I and tofacitinib, which may arise upon pre-administration of tofacitinib. Altogether, our data indicated that an interaction existed between tofacitinib and baohuoside I and additional cares might be taken when they were co-administrated in clinic.

Human Carboxylesterase 1A Plays a Predominant Role in Hydrolysis of the Anti-Dyslipidemia Agent Fenofibrate in Humans

Fenofibrate, a marketed peroxisome proliferator-activated receptor-α (PPARα) agonist, has been widely used for treating severe hypertriglyceridemia and mixed dyslipidemia. As a canonical prodrug, fenofibrate can be rapidly hydrolyzed to release the active metabolite (fenofibric acid) in vivo, but the crucial enzyme(s) responsible for fenofibrate hydrolysis and the related hydrolytic kinetics have not been well-investigated. This study aimed to assign the key organs and crucial enzymes involved in fenofibrate hydrolysis in humans, as well as reveal the impact of fenofibrate hydrolysis on its non-PPAR-mediated biologic activities. Our results demonstrated that fenofibrate could be rapidly hydrolyzed in the preparations from both human liver and lung to release fenofibric acid. Reaction phenotyping assays coupling with chemical inhibition assays showed that human carboxylesterase 1A (hCES1A) played a predominant role in fenofibrate hydrolysis in human liver and lung, while human carboxylesterase 2A (hCES2A) and human monoacylglycerol esterase (hMAGL) contributed to a very lesser extent. Kinetic analyses showed that fenofibrate could be rapidly hydrolyzed by hCES1A in human liver preparations, while the inherent clearance of hCES1A-catalyzed fenofibrate hydrolysis is much higher (>200-fold) than than that of hCES2A or hMAGL. Biologic assays demonstrated that both fenofibrate and fenofibric acid showed very closed Nrf2 agonist effects, but fenofibrate hydrolysis strongly weakens its inhibitory effects against both hCES2A and hNtoum. Collectively, our findings reveal that the liver is the major organ and hCES1A is the predominant enzyme-catalyzing fenofibrate hydrolysis in humans, while fenofibrate hydrolysis significantly reduces inhibitory effects of fenofibrate against serine hydrolases. SIGNIFICANCE STATEMENT: Fenofibrate can be completely converted to fenofibric acid in humans and subsequently exert its pharmacological effects, but the hydrolytic pathways of fenofibrate in humans have not been well-investigated. This study reported that the liver was the predominant organ and human carboxylesterase 1A was the crucial enzyme involved in fenofibrate hydrolysis in humans.

Research Methods and New Advances in Drug-Drug Interactions Mediated by Renal Transporters

The kidney is critical in the human body's excretion of drugs and their metabolites. Renal transporters participate in actively secreting substances from the proximal tubular cells and reabsorbing them in the distal renal tubules. They can affect the clearance rates (CLr) of drugs and their metabolites, eventually influence the clinical efficiency and side effects of drugs, and may produce drug-drug interactions (DDIs) of clinical significance. Renal transporters and renal transporter-mediated DDIs have also been studied by many researchers. In this article, the main types of in vitro research models used for the study of renal transporter-mediated DDIs are membrane-based assays, cell-based assays, and the renal slice uptake model. In vivo research models include animal experiments, gene knockout animal models, positron emission tomography (PET) technology, and studies on human beings. In addition, in vitro-in vivo extrapolation (IVIVE), ex vivo kidney perfusion (EVKP) models, and, more recently, biomarker methods and in silico models are included. This article reviews the traditional research methods of renal transporter-mediated DDIs, updates the recent progress in the development of the methods, and then classifies and summarizes the advantages and disadvantages of each method. Through the sorting work conducted in this paper, it will be convenient for researchers at different learning stages to choose the best method for their own research based on their own subject's situation when they are going to study DDIs mediated by renal transporters.

Aging and aging-related diseases: from molecular mechanisms to interventions and treatments

Aging is a gradual and irreversible pathophysiological process. It presents with declines in tissue and cell functions and significant increases in the risks of various aging-related diseases, including neurodegenerative diseases, cardiovascular diseases, metabolic diseases, musculoskeletal diseases, and immune system diseases. Although the development of modern medicine has promoted human health and greatly extended life expectancy, with the aging of society, a variety of chronic diseases have gradually become the most important causes of disability and death in elderly individuals. Current research on aging focuses on elucidating how various endogenous and exogenous stresses (such as genomic instability, telomere dysfunction, epigenetic alterations, loss of proteostasis, compromise of autophagy, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, deregulated nutrient sensing) participate in the regulation of aging. Furthermore, thorough research on the pathogenesis of aging to identify interventions that promote health and longevity (such as caloric restriction, microbiota transplantation, and nutritional intervention) and clinical treatment methods for aging-related diseases (depletion of senescent cells, stem cell therapy, antioxidative and anti-inflammatory treatments, and hormone replacement therapy) could decrease the incidence and development of aging-related diseases and in turn promote healthy aging and longevity.