Cellular and Molecular Mechanisms of MEK1 Inhibitor-Induced Cardiotoxicity.

Background: Trametinib is a MEK1 (mitogen-activated extracellular signal-related kinase kinase 1) inhibitor used in the treatment of BRAF (rapid accelerated fibrosarcoma B-type)-mutated metastatic melanoma. Roughly 11% of patients develop cardiomyopathy following long-term trametinib exposure. Although described clinically, the molecular landscape of trametinib cardiotoxicity has not been characterized. Objectives: The aim of this study was to test the hypothesis that trametinib promotes widespread transcriptomic and cellular changes consistent with oxidative stress and impairs cardiac function. Methods: Mice were treated with trametinib (1 mg/kg/d). Echocardiography was performed pre- and post-treatment. Gross, histopathologic, and biochemical assessments were performed to probe for molecular and cellular changes. Human cardiac organoids were used as an in vitro measurement of cardiotoxicity and recovery. Results: Long-term administration of trametinib was associated with significant reductions in survival and left ventricular ejection fraction. Histologic analyses of the heart revealed myocardial vacuolization and calcification in 28% of animals. Bulk RNA sequencing identified 435 differentially expressed genes and 116 differential signaling pathways following trametinib treatment. Upstream gene analysis predicted interleukin-6 as a regulator of 17 relevant differentially expressed genes, suggestive of PI3K/AKT and JAK/STAT activation, which was subsequently validated. Trametinib hearts displayed elevated markers of oxidative stress, myofibrillar degeneration, an 11-fold down-regulation of the apelin receptor, and connexin-43 mislocalization. To confirm the direct cardiotoxic effects of trametinib, human cardiac organoids were treated for 6 days, followed by a 6-day media-only recovery. Trametinib-treated organoids exhibited reductions in diameter and contractility, followed by partial recovery with removal of treatment. Conclusions: These data describe pathologic changes observed in trametinib cardiotoxicity, supporting the exploration of drug holidays and alternative pharmacologic strategies for disease prevention.

Application of Pharmacokinetic Prediction Platforms in the Design of Optimized Anti-Cancer Drugs.

Cancer is the second most common cause of death in the United States, accounting for 602,350 deaths in 2020. Cancer-related death rates have declined by 27% over the past two decades, partially due to the identification of novel anti-cancer drugs. Despite improvements in cancer treatment, newly approved oncology drugs are associated with increased toxicity risk. These toxicities may be mitigated by pharmacokinetic optimization and reductions in off-target interactions. As such, there is a need for early-stage implementation of pharmacokinetic (PK) prediction tools. Several PK prediction platforms exist, including pkCSM, SuperCypsPred, Pred-hERG, Similarity Ensemble Approach (SEA), and SwissADME. These tools can be used in screening hits, allowing for the selection of compounds were reduced toxicity and/or risk of attrition. In this short commentary, we used PK prediction tools in the optimization of mitogen activated extracellular signal-related kinase kinase 1 (MEK1) inhibitors. In doing so, we identified MEK1 inhibitors with retained activity and optimized predictive PK properties, devoid of hERG inhibition. These data support the use of publicly available PK prediction platforms in early-stage drug discovery to design safer drugs.

Targeted rehabilitation to improve outcome after total knee replacement (TRIO): study protocol for a randomised controlled trial.

BACKGROUND: Approximately 20% of patients are not satisfied with the outcome of total knee replacement, great volumes of which are carried out yearly. Physiotherapy is often provided by the NHS to address dysfunction following knee replacement; however the efficacy of this is unknown. Although clinically it is accepted that therapy is useful, provision of physiotherapy to all patients post-operatively does not enhance outcomes at one year. No study has previously assessed the effect of targeting therapy to individuals struggling to recover in the early post-operative phase.The aim of the TRIO study is to determine whether stratifying care by targeting physiotherapy to those individuals performing poorly following knee replacement is effective in improving the one year outcomes. We are also investigating whether the structure of the physiotherapy provision itself influences outcomes. METHODS/DESIGN: The study is a multi-centre prospective randomised controlled trial (RCT) of patients undergoing primary total knee replacement, with treatment targeted at those deemed most susceptible to gain from it. Use of the national PROMS programme for pre-operative data collection allows us to screen all patients at initial post-operative clinical review, and recruit only those deemed to be recovering slowly.We aim to recruit 440 patients through various NHS orthopaedic centres who will undergo six weeks of physiotherapy. The intervention will be either 'intensive' involving both hospital and home-based functional exercise rehabilitation, or 'standard of care' consisting of home exercises. Patients will be randomised to either group using a web-based system. Both groups will receive pre and post-intervention physiotherapy review. Patients will be followed-up to one year post-operation. The primary outcome measure is the Oxford Knee Score. Secondary outcomes are patient satisfaction, functional ability, pain scores and cost-effectiveness. TRIAL REGISTRATION: Current Controlled Trials ISRCTN23357609. ClinicalTrials.gov NCT01849445.

Effect of water quality management efforts on wastewater loadings during the past century.

The history of wastewater discharges to the Hudson River watershed from Troy, New York, to the New York City Harbor was traced from 1900 to 2000. The parameters studied include population, flow, type of treatment, biochemical oxygen demand, suspended solids, total nitrogen, and total phosphorus. This paper details a methodology for estimating historic loadings where data are lacking. The data show dramatic changes in wastewater loadings. There has been a continued increase in wastewater flow and population over the past century but a decrease in contaminant loading during the last 25 years. The reduction in effluent loads is directly related to state and federal water quality management programs and the substantial public and private investment made in upgrading point source water pollution control infrastructure. A comparison of point with nonpoint source loads shows that although nonpoint sources are now a significant contributor of contaminants to the river, point sources remain as major sources of total nitrogen and total phosphorus.