Basic & Clinical Pharmacology & Toxicology最新文献

Quercetin is known to reduce blood pressure (BP); however, its acute effects are unclear. We investigated the acute effects of quercetin on BP, aortic mechanical properties and vascular reactivity in female Sprague–Dawley (SD) rats. Hypertension was induced using L-NAME (40 mg/kg/day). Quercetin (4.5 mg/kg) was administered intravenously. Mechanical properties of the aortae were measured by echo-tracking in normotensive and hypertensive rats. L-NAME and quercetin quantities in the aorta were determined using AP-MALDI-MSI. Vascular reactivity was performed in mesenteric and renal arteries. L-NAME increased BP and PWVβ while decreasing strain. Quercetin decreased BP and ameliorated PWVβ in L-NAME-induced hypertensive rats. Ex vivo, the acetylcholine (ACh)-induced increase in tension at 100 μM was reduced in renal arteries when exposed to quercetin while phenylephrine (Phe)-induced contractile response was augmented. In quiescent rings of renal arteries incubated with L-NAME (10 μM) and TRAM-34 (1 μM), the ACh-induced vasoconstrictions were inhibited by quercetin. Quercetin resulted in concentration-dependent vasodilation in mesenteric arteries and increased its sensitivity to ACh-induced relaxations. Quercetin lowered BP in L-NAME-induced hypertensive rats, likely due to changes in aortic mechanical properties and relaxation of resistance arteries. Further research is warranted to clarify the acute effects of quercetin on renal arteries in this hypertensive model.

Raloxifene has low bioavailability due to extensive glucuronidation in the intestine and the liver, and its pharmacokinetics is associated with high intra- and interindividual variability. Some of this variability could be explained by the enterohepatic recycling of raloxifene, which is driven by transporter-mediated uptake and efflux and gut microbial deglucuronidation of raloxifene glucuronides. These individual processes involved in raloxifene disposition, however, have not been characterized in full detail. In this study, we evaluated the interactions of raloxifene and its three glucuronide metabolites (raloxifene 4′-glucuronide, raloxifene 6-glucuronide and raloxifene 4′,6-diglucuronide) with drug transporters using Sf9 membrane vesicles and HEK293 cells. Additionally, we measured the deglucuronidation of raloxifene glucuronides in human faecal extracts. All raloxifene glucuronides were transported by MRP2 and MRP3, whereas raloxifene monoglucuronides were identified as substrates of OATP1B1, OATP1B3 and OATP2B1. All three raloxifene glucuronides were readily deglucuronidated in the presence of faecal extracts, although with high between-subject variability. The results of this study provide further understanding of the disposition of raloxifene, which can help understand the sources behind the interindividual variability in raloxifene pharmacokinetics.

In a 2022 consultation, the UK public highlighted the need to disseminate trial results to participants. We assess whether the information provided to trial participants in publicly available participant information sheets (PISs) of trials conducted in the UK is helpful for future trials. This cross-sectional study is based on a search conducted on 18 August 2023 on ClinicalTrials.gov looking for UK completed or terminated phase 2–4 medicine trials. The posted PIS (or the protocol, if the PIS was unavailable) were reviewed checking the text used to inform participants on how results will be disseminated to participants. Of the 48 records retrieved, 32 were included: 23 and 9 had the PIS or the protocol posted, respectively. Seven (22%) did not mention dissemination of results to participants. Thirteen (41%) used the same short “common, standard text” of four sentences to inform participants. This text mentioned ClinicalTrials.gov as the source for further information and US Law as the reason for it. Twelve (38%) used different texts with different scopes and lengths. These results showed that publicly available PISs of medicinal product trials conducted in the UK are very limited and of scarce utility for investigators aiming to start a new trial.

Ulcerative colitis (UC) is an inflammatory bowel disease and psychological factors may be one of its pathogeneses. Selective serotonin reuptake inhibitor drug such as paroxetine with an effective anti-depression ability may be a new option for UC treatment. To evaluate the therapeutic effect of paroxetine on the exacerbation of UC symptoms caused by depression, a dual model of C57BL/6 mice was established using dextran sulphate sodium and chronic unpredictable mild stress (CUMS). Behavioural experiments, H&E staining and the level of 5-hydroxytryptamine (5-HT) in the brain were used to demonstrate successful replication of the CUMS model. The levels of 5-HT, TNF-α and IL-1β in the colon and the activity of MPO in the serum were determined by ELISA kits. The levels of some gut microbiota in the faeces were measured by qPCR and faecal differential metabolites were analysed by ¹H NMR. The results indicate that CUMS can exacerbate UC symptoms in mice by exacerbating inflammation, and UC+CUMS can disrupt gut microbiota and fatty acid metabolism. Paroxetine can improve the mental state of mice, reduce serum MPO activity, but increase TNF-α and IL-1β levels in the colon. In addition, paroxetine also can restore the intestinal flora of mice and improve intestinal absorption and metabolic function of amino acids and short-chain fatty acids.

Autophagy is a vital mechanism that eliminates large cytoplasmic components via lysosomal degradation to maintain cellular homeostasis. The role of autophagy in cancer treatment has been studied extensively. Autophagy primarily prevents tumour initiation by maintaining genomic stability and preventing cellular inflammation. However, autophagy also supports cancer cell survival and growth by providing essential nutrients for therapeutic resistance. Thus, autophagy has emerged as a promising strategy for overcoming resistance and enhancing anti-cancer therapy. Inhibiting autophagy significantly improves the sensitivity of lung, colorectal, breast, liver and prostate cancer cells to tumour necrosis factor-related apoptosis-inducing ligand (TRAIL). This review investigates the intricate interplay between autophagy modulation and TRAIL-based therapy, specifically focussing on comparing the efficacy of late-stage autophagy inhibition versus early-stage inhibition in overcoming cancer resistance. We expose the distinctive advantages of late-stage autophagy inhibition by exploring the mechanisms underlying autophagy's impact on TRAIL sensitivity. Current preclinical and clinical investigations are inspected, showing the potential of targeting late-stage autophagy for sensitizing resistant cancer cells to TRAIL-induced apoptosis. This review emphasizes the significance of optimizing autophagy modulation to enhance TRAIL-mediated therapy and overcome the challenge of treatment resistance in cancer. We offer insights and recommendations for guiding the development of potential therapeutic strategies aimed at overcoming the challenges posed by treatment-resistant cancers.

Angelman Syndrome (AS) is a neurodevelopmental disorder caused by the loss of function of ubiquitin-protein ligase E3A (UBE3A), resulting in marked changes in synaptic plasticity. In AS mice, a dysregulation of Ca²⁺/calmodulin-dependent protein kinase II alpha (CaMKIIα) was previously described. This has been convincingly validated through genetic rescue of prominent phenotypes in mouse cross-breeding experiments. Selective ligands that specifically stabilize the CaMKIIα central association (hub) domain and affect different conformational states in vitro are now available. Two of these ligands, 3-hydroxycyclopent-1-enecarboxylic acid (HOCPCA) and (E)-2-(5-hydroxy-2-phenyl-5,7,8,9-tetrahydro-6H-benzo[7]annulen-6-ylidene)acetic acid (Ph-HTBA), confer neuroprotection after ischemic stroke in mice where CaMKIIα is known to be dysregulated. Here, we sought to investigate whether pharmacological modulation with these prototypical CaMKIIα hub ligands presents a viable approach to alleviate AS symptoms. We performed an in vivo functional evaluation of AS mice treated for a total of 14 days with either HOCPCA or Ph-HTBA (7 days pre-treatment and 7 days of behavioural assessment). Both compounds were well-tolerated but unable to revert robust phenotypes of motor performance, anxiety, repetitive behaviour or seizures in AS mice. Biochemical experiments subsequently assessed CaMKIIα autophosphorylation in AS mouse brain tissue. Taken together our results indicate that pharmacological modulation of CaMKIIα via the selective hub ligands used here is not a viable treatment strategy in AS.

The MDM2-p53 pathway plays a pivotal role in regulating cell cycle and apoptosis, with its dysfunction contributing to approximately 50% of human malignancies. MDM2, an E3 ubiquitin ligase, targets the tumour suppressor p53 for degradation, thereby promoting uncontrolled cell growth in cancers. Inhibiting the MDM2-p53 interaction represents a promising therapeutic strategy for reactivating p53’s tumour-suppressive functions. This study explored the potential of ibutamoren (IBU) as a novel inhibitor of MDM2. In silico analyses utilizing molecular modelling revealed that IBU has a low IC₅₀ for MDM2 inhibition and favourably binds to the p53-binding pocket of MDM2. In vitro experiments demonstrated that IBU treatment reduced the viability of immortalized cancer cell lines with a functional MDM2-p53 pathway but not in cell lines where this pathway harboured damaging mutations. This trend was further supported by RT-qPCR analysis, which showed differential expression of two p53 target genes upon IBU treatment in cell lines with wild MDM2-p53 pathways but not in those harbouring damaging mutations. These findings provide preliminary evidence supporting IBU's anticancer activity, plausibly through the MDM2-p53 pathway, and suggest that further studies are warranted to explore its mechanism of action and potential development as a lead compound in oncology research.

Natural products constitute a vast source of bioactive compounds with the potential of providing valuable insight for future medicines. However, from a pharmacological perspective, natural product studies are also often accompanied by serious limitations due to, for example, the complex nature of biological extracts, the challenge of reproducibly characterizing the extract and providing an exhaustive list of constituents and, consequently, the difficulties in linking the observed pharmacological effects to specific chemical entities. The present paper discusses the major challenges of studies with natural products and provides a guideline to be followed by authors submitting research findings involving data from natural products, and their derivatives, to Basic & Clinical Pharmacology & Toxicology.

Daptomycin, an anti-methicillin-resistant Staphylococcus aureus drug, causes exposure-dependent muscle toxicity and eosinophilic pneumonia. Although the area under the concentration-time curve (AUC)-guided dosing is crucial, an optimal blood sampling strategy is lacking. This study aimed to identify an optimal limited sampling strategy using Bayesian forecasting to rapidly achieve the target AUC. Two validated population pharmacokinetic models generated a virtual population of 1000 individuals (models 1 and 2 represent diverse patients and kidney transplant recipients, respectively). The AUC for each blood sample was assessed using the probability of achieving the estimated/reference AUC ratio on the second day (AUC_24–48) and at the steady state (AUC_ss). In Model 1, Bayesian posterior probabilities for AUC_24–48 increased from 50.7% (a priori) to 59.4% and for AUC_ss from 48.9% (a priori) to 61.9%, with one-point C_trough sampling at 24 h. With two-point sampling at 7 and 24 h, the probabilities increased to 73.8% for AUC_24–48 and 69.7% for AUC_ss. In Model 2, the probabilities for both AUC_24–48 and AUC_ss with one-point C_trough or two-point sampling incorporating C_trough sampling increased compared to a priori probabilities. These results suggest that two-point sampling incorporating C_trough during initial dosing enhanced achieving the target AUC_24–48 and AUC_ss rapidly.