Impact of genetic polymorphisms of cytochrome P450 2 C (CYP2C) enzymes on the drug metabolism and design of antidiabetics

Tuberculosis-diabetes comorbidities: Mechanistic insights for clinical considerations and treatment challenges

Tuberculosis (TB) remains a leading cause of death among infectious diseases, particularly in poor countries. Viral infections, multidrug-resistant and ex-tensively drug-resistant TB strains, as well as the coexistence of chronic illnesses such as diabetes mellitus (DM) greatly aggravate TB morbidity and mortality. DM [particularly type 2 DM (T2DM)] and TB have converged making their control even more challenging. Two contemporary global epidemics, TB-DM behaves like a syndemic, a synergistic confluence of two highly prevalent diseases. T2DM is a risk factor for developing more severe forms of multi-drug resistant-TB and TB recurrence after preventive treatment. Since a bidirectional relationship exists between TB and DM, it is necessary to concurrently treat both, and promote recommendations for the joint management of both diseases. There are also some drug-drug interactions resulting in adverse treatment outcomes in TB-DM patients including treatment failure, and reinfection. In addition, autophagy may play a role in these comorbidities. Therefore, the TB-DM comorbidities present several health challenges, requiring a focus on multidisciplinary collaboration and integrated strategies, to effectively deal with this double burden. To effectively manage the comorbidity, further screening in affected countries, more suitable drugs, and better treatment strategies are required.

Vital role of CYP450 in the biodegradation of antidiabetic drugs in the aerobic activated sludge system and the mechanisms

The extensive use of antidiabetic drugs (ADDs) and their detection in high concentrations in the environment have been extensively documented. However, the mechanism of ADDs dissipation in aquatic environments is still not well understood. This study thoroughly investigates the dissipation behavior of ADDs and the underlying mechanisms in the aerobic activated sludge system. The results indicate that the removal efficiencies of ADDs range from 3.98% to 100% within 48 h, largely due to the biodegradation process. Additionally, the gene expression of cytochrome P450 (CYP450) is shown to be significantly upregulated in most ADDs-polluted samples (P < 0.05), indicating the vital role of CYP450 enzymes in the biodegradation of ADDs. Enzyme inhibition experiments validated this hypothesis. Moreover, molecular docking and simulation results indicate that a strong correlation between the biodegradation of ADDs and the interactions between ADDs and CYP450 (Ebinding). The differences in dissipation behavior among the tested ADDs are possibly due to their electrophilic characteristics. Overall, this study makes the initial contribution to a more profound comprehension of the crucial function of CYP450 enzymes in the dissipation behavior of ADDs in a typical aquatic environment.

Evaluation of Zhenwu Decoction Effects on CYP450 Enzymes in Rats Using a Cocktail Method by UPLC-MS/MS

This thesis is aimed at shedding light on the effects of the Zhenwu decoction (ZWD) on the activities and mRNA expressions of seven CYP450 isoenzymes. In the first step, we determined the main chemical compounds of ZWD by high-performance liquid chromatography (HPLC). Next, 48 male (SD) rats were randomly divided into the normal saline (NS) group and the ZWD low- (2.1875 g/kg), medium- (4.375 g/kg), and high- (8.75 g/kg) dose groups (12 per group). All rats were gavaged once daily for 28 consecutive days. A mixed solution of seven probe drugs was injected into 24 rats through the caudal vein after the last intragastric administration. Lastly, a validated cocktail method and real-time quantitative reverse-transcription polymerase chain reaction (RT-qPCR) were used to detect pharmacokinetic parameters and mRNA expressions, respectively. Compared with the NS group, ZWD at medium- and high-dose groups could significantly induce CYP2C6 (P < 0.05) activity, while the mRNA expression (P < 0.05) increased only in the high-dose group. Additionally, CYP2C11 activity was induced and consistent with mRNA expression (P < 0.05). Moreover, ZWD could induce the activity of CYP3A1 (P < 0.05), but the mRNA expression showed no significant differences except in high-dose groups. Additionally, ZWD has no effects on CYP1A2, CYP2B1, CYP2C7, and CYP2D2. In conclusion, the significant inductive effects of ZWD on three CYP450 isoenzymes indicated that when ZWD was coadministrated with drugs mediated by these enzymes, not only should the potential herb-drug interactions (HDIs) be observed, but the dosage adjustment and tissue drug concentration should also be considered. Furthermore, the approach described in this article can be applied to study the importance of gender, age, and disease factors to HDI prediction.

A Cocktail Interaction Study Evaluating the Drug-Drug Interaction Potential of the Perpetrator Drug ASP8477 at Multiple Ascending Dose Levels

ASP8477 (molecular weight 325.36 g/mol) is a fatty acid amide hydrolase inhibitor intended for the treatment of neuropathic pain. Results from in vitro studies indicated that ASP8477 is a direct inhibitor of cytochrome P450 (CYP) 2C8, 2C9, 2C19, 2D6, and 3A4 enzymes at expected efficacious concentrations, with the strongest effect on CYP2C19; a phase 1 study confirmed ASP8477 to be a CYP2C19 inhibitor. To further evaluate the interaction potential of ASP8477, a cocktail interaction study was performed using the probe substrates of the validated Inje cocktail containing losartan (CYP2C9), omeprazole (CYP2C19), dextromethorphan (CYP2D6), and midazolam (CYP3A4). Because ASP8477 shows nonlinear pharmacokinetics, 3 doses (20, 60, and 100 mg) were evaluated. This study revealed changes in exposure (area under the concentration‐time curve) of the probe substrates after treatment with 20, 60, and 100 mg ASP8477, respectively, compared with substrates alone with geometric mean ratios of: midazolam, 119%, 151%, and 158%; losartan, 107%, 144%, and 190%; omeprazole, 213%, 456%, and 610%; and dextromethorphan, 138%, 340%, and 555% (with increasing doses, respectively). Overall, ASP8477 was a weak inhibitor for CYP3A4 and CYP2C9, a moderate to strong inhibitor for CYP2C19, and a weak to strong inhibitor for CYP2D6, with doses from 20 to 100 mg. This study confirmed that the Inje cocktail approach was able to detect relevant drug‐drug interactions impacting further development of ASP8477 and future therapeutic use. With the approach used here, the inhibiting effect of a perpetrator drug on different CYP enzymes can be evaluated, and at different doses, thereby supporting dose recommendations for potential interactions.

Clinical management of concurrent diabetes and tuberculosis and the implications for patient services

Diabetes triples the risk for active tuberculosis, thus the increasing burden of type 2 diabetes will help to sustain the present tuberculosis epidemic. Recommendations have been made for bidirectional screening, but evidence is scarce about the performance of specific tuberculosis tests in individuals with diabetes, specific diabetes tests in patients with tuberculosis, and screening and preventive therapy for latent tuberculosis infections in individuals with diabetes. Clinical management of patients with both diseases can be difficult. Tuberculosis patients with diabetes have a lower concentration of tuberculosis drugs and a higher risk of drug toxicity than tuberculosis patients without diabetes. Good glycaemic control, which reduces long-term diabetes complications and could also improve tuberculosis treatment outcomes, is hampered by chronic inflammation, drug-drug interactions, suboptimum adherence to drug treatments, and other factors. Besides drug treatments for tuberculosis and diabetes, other interventions, such as education, intensive monitoring, and lifestyle interventions, might be needed, especially for patients with newly diagnosed diabetes or those who need insulin. From a health systems point of view, delivery of optimum care and integration of services for tuberculosis and diabetes is a huge challenge in many countries. Experience from the combined tuberculosis and HIV/AIDS epidemic could serve as an example, but more studies are needed that include economic assessments of recommended screening and systems to manage concurrent tuberculosis and diabetes.

CYP2C metabolism of oral antidiabetic drugs--impact on pharmacokinetics, drug interactions and pharmacogenetic aspects

INTRODUCTION

The cytochrome P4502C enzymes account for the metabolism of approximately 20% of therapeutic drugs including certain oral antidiabetic drugs (OADs).

AREAS COVERED

This review focuses on the effect of CYP2C enzymes on metabolism of sulphonylureas (SUs), meglitinides, and thiazolidinediones (TZDs) discussing their impact on pharmacokinetics, drug interactions and toxicological profiles. Pharmacogenetic aspects reflecting individual gene variants and variable drug effects are also considered.

EXPERT OPINION

Genetic polymorphisms of CYP2C9 enzymes (*2/*2, *2/*3, *3/*3) influence the glycaemic response to SUs and impair their substrate metabolism. Restricted data from small-sized studies with heterogenous definitions of hypoglycaemia revealed no clear association between CYP2C9 genotypes and the risk of hypoglycaemia. Functional polymorphisms of CYP2C8- and CYP2C9 drug metabolizing genes affect markedly pharmacokinetics of meglitinides. Compared to wild-type carriers, patients treated with TZDs and carrying the common CYP2C8*3 and *4 variants showed a reduced glycaemic control. The strong CYP2C8 and OATP1B1 inhibitor gemfibrozil increases substantially the plasma concentrations of repaglinide and TZDs. Numerous metabolic drug interactions exist between SUs and commonly prescribed drugs, especially anti-infectives. The complex pharmacokinetic and pharmacogenetic properties and the unfavourable short and long term risk profile of glibenclamide and glimepiride raise the question whether their use can be justified any longer.