Towards human ex vivo organ perfusion models to elucidate drug pharmacokinetics in health and disease

Abstract

To predict the absorption, distribution, metabolism and excretion (ADME) profile of candidate drugs a variety of preclinical models can be applied. The ADME and toxicological behavior of newly developed drugs are often investigated prior to assessment in humans, which is associated with long time-lines and high costs. Therefore, good predictions of ADME profiles earlier in the drug development process are very valuable. Good prediction of intestinal absorption and renal and biliary excretion remain especially difficult, as there is an interplay of active transport and metabolism involved. To study these processes, including enterohepatic circulation, ex vivo tissue models are highly relevant and can be regarded as the bridge between in vitro and in vivo models. In this review the current in vitro, in vivo and in more detail ex vivo models for studying pharmacokinetics in health and disease are discussed. Additionally, we propose novel models, i.e., perfused whole-organs, which we envision will generate valuable pharmacokinetic information in the future due to improved translation to the in vivo situation. These machine-perfused organ models will be particularly interesting in combination with biomarkers for assessing the functionality of transporter and CYP450 proteins.     

Antioxidant imbalance and genotoxicity detected in fish induced by titanium dioxide nanoparticles (NpTiO2) and inorganic lead (PbII)

Titanium dioxide nanoparticles (NpTiO₂) are the most widely-used nanoparticle type and the adsorption of metals such as lead (PbII) onto their surface is a major source of concern to scientists. This study evaluated the effects of the associated exposure to both types of contaminant, i.e., lead (a known genotoxic metal) and NpTiO₂, in a freshwater fish (Astyanax serratus) through intraperitoneal injection for an acute assay of 96 h. The effects of this exposure were evaluated using the comet assay, DNA diffusion assay and piscine micronucleus test, as well as the quantification of antioxidant enzymes (SOD, CAT, and GST) and metallothioneins. Our findings indicate that co-exposure of PbII with NpTiO₂ can provoke ROS imbalances, leading to DNA damage in the blood and liver tissue of A. serratus, as well as modifying erythropoiesis in this species, inducing necrosis and changing the nuclear morphology of the erythrocytes.     

Investigation of the miRNA146a and miRNA155 gene expression levels in patients with multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disease and the most common neurodegenerative status. MicroRNAs play an important role in macrophage response to inflammatory processes, and alterations in miRNA levels trigger the inactivation of specific T lymphocytes. As a result, these factors can lead to autoimmune diseases such as MS. Therefore, to determine the role of MicroRNA-146a and MicroRNA-155 in MS patients, their expression levels in serum of MS patients were compared with healthy controls.In this study, the expression levels of MicroRNA-146a and MicroRNA-155 in 30 serum samples of MS and healthy patients as a control group. MicroRNA extraction and cDNA synthesis was performed according manufacture protocols. The expression levels of MicroRNAs were evaluated by Real Time-PCR.MicroRNA-146a and MicroRNA-155 levels were increased in patients with MS compared to controls. The results demonstrated that EDSS score are increased with increasing level of MicroRNA-146a and MicroRNA-155. ROC curve analysis showed that the area under curve (AUC) was significant for MicroRNA-146a and MicroRNA-155.Increased expression levels of MicroRNA-146a and MicroRNA-155 may be associated with the pathogenesis of MS disease. If this study is conducted in a larger sample population and the above results can be used to identify patients or control patients who are under medical care.     

RNA sequencing steps toward the first line

• DNA is the sequence that codes for proteins.
• Messenger RNA is transcribed from the DNA sequence of genes and translated into protein.
• It can be difficult to predict how a change in the DNA sequence will affect messenger RNA and protein quantity and quality.
• DNA translocation changes can cause the joining of sequences from two different genes or different parts of the same gene.
• DNA sequencing is often used clinically to predict how DNA changes might affect proteins.
• Alternatively, RNA sequencing can be used as a more direct measure of the effect of DNA changes on the protein products.
• This sequencing is important for identifying changes in cancer that may indicate response to targeted therapy, prognosis, or diagnosis.

     

Effects of Spironolactone Treatment in Elderly Women With Heart Failure and Preserved Left Ventricular Ejection Fraction

BackgroundAlthough spironolactone has been shown to decrease morbidity and mortality in patients with heart failure and reduced left ventricular ejection fraction, its role in patients with heart failure and preserved left ventricular ejection fraction (HFpEF) is not well defined. In this study we investigated the mechanisms involved when elderly women with HFpEF are treated with spironolactone.Methods and ResultsForty-eight women with HFpEF were enrolled in a randomized placebo-controlled trial and were assigned to 25 mg spironolactone daily (n = 24) or placebo (n = 24) for 6 months. Six-minute walk distance, clinical composite score, Doppler echocardiography, and biomarkers were determined at baseline and after 3 and 6 months of therapy. Six months of spironolactone treatment stabilized clinical symptoms, as demonstrated by significant worsening of the clinical composite score in the placebo group (P = .02). In addition, spironolactone treatment improved diastolic function by significantly increasing early diastolic tissue Doppler velocity of the lateral mitral annulus (lateral e′; P = .003) and significantly reducing the mitral peak E velocity to lateral e′ ratio (lateral E/e′; P = .0001). Finally, spironolactone favorably affected remodeling through a reduction in myocardial fibrosis measured by a reduction in type III procollagen levels (P = .035). Six-minute walk distance did not significantly improve with spironolactone treatment compared with placebo.ConclusionsSpironolactone stabilizes functional capacity and symptoms and improves diastolic function, possibly through its ability to suppress type III procollagen synthesis.