Tacrine was the first drug used in the therapy of Alzheimer's disease (AD) and is one of the leading structures frequently pursued in the drug discovery of novel candidates for tackling AD. However, because tacrine has been withdrawn from the market due to its hepatotoxicity, ascribed to specific metabolites, concerns are high about the toxicity profile of newly developed compounds related to tacrine. From the point of view of drug safety, the formation of metabolites must be uncovered and analyzed. Bearing in mind that the main culprit of tacrine hepatotoxicity is its biotransformation to hydroxylated metabolites, human liver microsomes were used as a biotransformation model. Our study aims to clarify phase I metabolites of three potentially non-toxic tacrine derivatives (7-methoxytacrine, 6-chlorotacrine, 7-phenoxytacrine) and to semi-quantitatively determine the relative amount of individual metabolites as potential culprits of tacrine-based hepatotoxicity. For this purpose, a new selective UHPLC-Orbitrap method has been developed. Applying UHPLC-Orbitrap method, two as yet unpublished tacrine and 7-methoxytacrine monohydroxylated metabolites have been found and completely characterized, and the separation of ten dihydroxylated tacrine and 7-methoxytacrine metabolites was achieved for the first time. Moreover, the structures of several new metabolites of 7-phenoxytacrine and 6-chlorotacrine have been identified. In addition, the relative amount of these newly observed metabolites was determined. Based on the results and known facts about the toxicity of tacrine metabolites published so far, it appears that 7-phenoxytacrine and 6-chlorotacrine could be substantially less hepatotoxic compared to tacrine, and could potentially pave the way for metabolically safe molecules applicable in AD therapy.
- MeSH
- Alzheimerova nemoc * farmakoterapie metabolismus MeSH
- cholinesterasové inhibitory chemie MeSH
- jaterní mikrozomy metabolismus MeSH
- lékové postižení jater * metabolismus MeSH
- lidé MeSH
- takrin MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Tacrine was withdrawn from clinical use as a drug against Alzheimer's disease in 2013, mainly due to drug-induced liver injury. The culprit of tacrine-associated hepatotoxicity is believed to be the 7-OH-tacrine metabolite, a possible precursor of quinone methide (Qmeth), which binds to intracellular -SH proteins. In our study, several different animal and human models (liver microsomes, primary hepatocytes, and liver slices) were used to investigate the biotransformation and hepatotoxicity of tacrine and its 7-substituted analogues (7-methoxy-, 7-phenoxy-, and 7-OH-tacrine). Our goal was to find the most appropriate in vitro model for studying tacrine hepatotoxicity and, through rational structure modifications, to develop derivatives of tacrine that are less prone to Qmeth formation. Our results show that none of animal models tested accurately mimic human tacrine biotransformation; however, the murine model seems to be more suitable than the rat model. Tacrine metabolism was overall most accurately mimicked in three-dimensional (3D) spheroid cultures of primary human hepatocytes (PHHs). In this system, tacrine and 7-methoxytacrine were hydroxylated to 7-OH-tacrine, whereas 7-phenoxytacrine formed, as expected, only trace amounts. Surprisingly, however, our study showed that 7-OH-tacrine was the least hepatotoxic (7-OH-tacrine < tacrine < 7-methoxytacrine < 7-phenoxytacrine) even after doses had been adjusted to achieve the same intracellular concentrations. The formation of Qmeth-cysteine and Qmeth-glutathione adducts after human liver microsome incubation was confirmed by all of the studied tacrine derivatives, but these findings were not confirmed after incubation with 3D PHH spheroids. Therefore, the presented data call into question the suggested previously hypothesized mechanism of toxicity, and the results open new avenues for chemical modifications to improve the safety of novel tacrine derivatives.
- MeSH
- biotransformace MeSH
- indolochinony * MeSH
- krysa rodu rattus MeSH
- lékové postižení jater * MeSH
- lidé MeSH
- methamfetamin * MeSH
- myši MeSH
- takrin toxicita MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Increasing life expectancy in modern society is undoubtedly due to improved healthcare, scientific advances in medicine, and the overall healthy lifestyle of the general population. However, this positive trend has led to an increase in the number of older people with a growing need for a sustainable system for the long-term care of this part of the population, which includes social and health services that are essential for a high quality of life. Longevity also brings challenges in the form of a polymorbid geriatric population that places financial pressure on healthcare systems. Regardless, one disease dominates the debate about financial sustainability due to the increasing numbers of people diagnosed, and that is Alzheimer's disease (AD). The presented paper aims to demonstrate the economic burden of social and healthcare services. Data from two regions in the Czech Republic were selected to demonstrate the potential scope of the problem. The future costs connected with AD are calculated by a prediction model, which is based on a population model for predicting the number of people with AD between 2020 and 2070. Based on the presented data from the two regions in the Czech Republic and the prediction model, several trends emerged. There appears to be a significant difference in the annual direct costs per person diagnosed with AD depending on the region in which they reside. This may lead to a significant inequality of the services a person can acquire followed by subsequent social issues that can manifest as a lower quality of life. Furthermore, given the prediction of the growing AD population, the costs expressed in constant prices based on the year 2020 will increase almost threefold during the period 2020-2070. The predicted threefold increase will place additional financial pressure on all stakeholders responsible for social and healthcare services, as the current situation is already challenging.
- Publikační typ
- časopisecké články MeSH
In order to identify novel lead structures for human toll-like receptor 4 (hTLR4) modulation virtual high throughput screening by a peta-flops-scale supercomputer has been performed. Based on the in silico studies, a series of 12 compounds related to tryptamine was rationally designed to retain suitable molecular geometry for interaction with the hTLR4 binding site as well as to satisfy general principles of drug-likeness. The proposed compounds were synthesized, and tested by in vitro and ex vivo experiments, which revealed that several of them are capable to stimulate hTLR4 in vitro up to 25% activity of Monophosphoryl lipid A. The specific affinity of the in vitro most potent substance was confirmed by surface plasmon resonance direct-binding experiments. Moreover, two compounds from the series show also significant ability to elicit production of interleukin 6.
- MeSH
- adjuvancia imunologická chemie metabolismus farmakologie MeSH
- CHO buňky MeSH
- Cricetulus MeSH
- inhibiční koncentrace 50 MeSH
- interleukin-6 krev MeSH
- lidé MeSH
- ligandy MeSH
- počítačová simulace MeSH
- povrchová plasmonová rezonance MeSH
- rychlé screeningové testy metody MeSH
- simulace molekulární dynamiky MeSH
- simulace molekulového dockingu MeSH
- toll-like receptor 4 agonisté metabolismus MeSH
- tryptaminy chemie MeSH
- vakcíny MeSH
- vazebná místa MeSH
- vztahy mezi strukturou a aktivitou * MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
