AIM: Serotonin is crucial for proper foetal development, and the placenta has been described as a 'donor' of serotonin for the embryo/foetus. However, in later stages of gestation the foetus produces its own serotonin from maternally-derived tryptophan and placental supply is no longer needed. We propose a novel model of serotonin homeostasis in the term placenta with special focus on the protective role of organic cation transporter 3 (OCT3/SLC22A3). METHODS: Dually perfused rat term placenta was employed to quantify serotonin/tryptophan transport and metabolism. Placental membrane vesicles isolated from human term placenta were used to characterize serotonin transporters on both sides of the syncytiotrophoblast. RESULTS: We obtained the first evidence that serotonin is massively taken up from the foetal circulation by OCT3. This uptake is concentration-dependent and inhibitable by OCT3 blockers of endogenous (glucocorticoids) or exogenous (pharmaceuticals) origin. Population analyses in rat placenta revealed that foetal sex influences placental extraction of serotonin from foetal circulation. Negligible foetal serotonin levels were detected in maternal-to-foetal serotonin/tryptophan transport and metabolic studies. CONCLUSION: We demonstrate that OCT3, localized on the foetus-facing membrane of syncytiotrophoblast, is an essential component of foeto-placental homeostasis of serotonin. Together with serotonin degrading enzyme, monoamine oxidase-A, this offers a protective mechanism against local vasoconstriction effects of serotonin in the placenta. However, this system may be compromised by OCT3 inhibitory molecules, such as glucocorticoids or antidepressants. Our findings open new avenues to explore previously unsuspected/unexplained complications during pregnancy including prenatal glucocorticoid excess and pharmacotherapeutic risks of treating pregnant women with OCT3 inhibitors.

• MeSH
• homeostáza MeSH
• krysa rodu rattus MeSH
• lidé MeSH
• membránové transportní proteiny pro serotonin metabolismus   MeSH
• monoaminoxidasa metabolismus   MeSH
• placenta * metabolismus   MeSH
• plod MeSH
• proteiny přenášející organické kationty metabolismus   MeSH
• serotonin * metabolismus   MeSH
• sexuální faktory MeSH
• těhotenství MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

In spite of remarkable reduction in the number of children born with HIV due to antiretroviral therapy, concerns remain on the short- and long-term effects of antiretroviral drugs at the feto-placental unit. Cardio- and skeletal myopathies have been reported in children exposed to antiretroviral drugs prenatally. These conditions have also been described in perturbed placental transfer of l-carnitine, an essential co-factor in fatty acid oxidation. Due to limited fetal and placental synthesis, carnitine supply is maintained through the placental carnitine uptake from maternal blood by the organic cation/carnitine transporters OCTN1 and OCTN2 (SLC22A4 and SLC22A5, respectively). The aim of our study was to investigate potential inhibition of placental carnitine uptake by a broad range of antiretroviral drugs comprising nucleoside/nucleotide reverse transcriptase inhibitors (lamivudine, zidovudine, abacavir, tenofovir disoproxil fumarate), non-nucleoside reverse transcriptase inhibitors (rilpivirine, efavirenz, etravirine), protease inhibitors (ritonavir, lopinavir, atazanavir, saquinavir, tipranavir), integrase inhibitors (raltegravir, dolutegravir, elvitegravir) and viral entry inhibitor, maraviroc. Studies in choriocarcinoma BeWo cells and human placenta-derived models confirmed predominant expression and function of OCTN2 above OCTN1 in l-carnitine transport. Subsequent screenings in BeWo cells and isolated MVM vesicles revealed seven antiretroviral drugs as inhibitors of the Na+-dependent l-carnitine uptake, corresponding to OCTN2. Ritonavir, saquinavir and elvitegravir showed the highest inhibitory potential which was further confirmed for ritonavir and saquinavir in placental fresh villous fragments. Our data indicate possible impairment in placental and fetal supply of l-carnitine with ritonavir and saquinavir, while suggesting retained placental carnitine transport with the other antiretroviral drugs.

• MeSH
• antiretrovirové látky toxicita   MeSH
• biologický transport MeSH
• hodnocení rizik MeSH
• karnitin metabolismus   MeSH
• lidé MeSH
• matka - expozice noxám škodlivé účinky   MeSH
• nádorové buněčné linie MeSH
• placenta účinky léků   metabolismus   MeSH
• proteiny přenášející organické kationty antagonisté a inhibitory   metabolismus   MeSH
• rodina nosičů rozpuštěných látek 22, člen 5 antagonisté a inhibitory   metabolismus   MeSH
• těhotenství MeSH
• Check Tag
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

Efavirenz (EFV) is a non-nucleoside reverse transcriptase inhibitor used in first-line combination antiretroviral therapy (cART). It is usually administered with nucleoside reverse transcriptase inhibitors (NRTI), many of which are substrates of OCT uptake solute carriers (SLC22A) and MATE (SLC47A), P-gp (MDR1, ABCB1), BCRP (ABCG2), or MRP2 (ABCC2) efflux transporters. The aim of this study was to evaluate the inhibitory potential of efavirenz towards these transporters and investigate its effects on the pharmacokinetics and tissue distribution of a known Oct/Mate substrate, lamivudine, in rats. Accumulation and transport assays showed that efavirenz inhibits the uptake of metformin by OCT1-, OCT2- and MATE1-expressing MDCK cells and reduces transcellular transport of lamivudine across OCT1/OCT2- and MATE1-expressing MDCK monolayers. Only negligible inhibition of MATE2-K was observed in HEK-MATE2-K cells. Efavirenz also reduced the efflux of calcein from MDCK-MRP2 cells, but had a rather weak inhibitory effect on Hoechst 33342 accumulation in MDCK-MDR1 and MDCK-BCRP cells. An in vivo pharmacokinetic interaction study in male Wistar rats revealed that intravenous injection of efavirenz or the control Oct/Mate inhibitor cimetidine significantly reduced the recovery of lamivudine in urine and greatly increased lamivudine retention in the renal tissue. Co-administration with efavirenz or cimetidine also increased the AUC0-∞ value and reduced total body clearance of lamivudine. These data suggest that efavirenz is a potent inhibitor of OCT/Oct and MATE/Mate transporters. Consequently, it can engage in drug-drug interactions that reduce renal excretion of co-administered substrates and enhance their retention in the kidneys, potentially compromising therapeutic safety.

• MeSH
• benzoxaziny farmakologie   MeSH
• buňky MDCK MeSH
• cimetidin farmakologie   MeSH
• eliminace ledvinami MeSH
• HEK293 buňky MeSH
• inhibitory reverzní transkriptasy farmakokinetika   farmakologie   moč   MeSH
• krysa rodu rattus MeSH
• lamivudin farmakokinetika   farmakologie   moč   MeSH
• ledviny metabolismus   MeSH
• lidé MeSH
• metformin metabolismus   farmakologie   MeSH
• plocha pod křivkou MeSH
• poločas MeSH
• potkani Wistar MeSH
• proteiny přenášející organické kationty antagonisté a inhibitory   metabolismus   MeSH
• proteiny spojené s mnohočetnou rezistencí k lékům antagonisté a inhibitory   metabolismus   MeSH
• psi MeSH
• ROC křivka MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• mužské pohlaví MeSH
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

1. Emtricitabine is a nucleoside reverse transcriptase inhibitor used in combination antiretroviral therapy of HIV (cART). Although active transport mechanisms are believed to mediate tubular secretion of the drug into urine, the responsible transporter and its potential to cause pharmacokinetic drug--drug interactions (DDI) has not been identified so far. The aim of this study was to investigate whether drug transporters P-gp (ABCB1), BCRP (ABCG2), MRP2 (ABCC2), OCT1 (SLC22A1), OCT2 (SLC22A2) or MATE1 (SLC47A1) can mediate active transcellular transfer of emtricitabine. 2. We employed transport assays in polarized monolayers of MDCK cells stably expressing P-gp, BCRP, MRP2, OCT1, OCT2 and/or MATE1. Among the transporters studied only MATE1 accelerated basal-to-apical transport of emtricitabine over a wide range of concentrations (6 nM to 1 mM). The transport was enhanced by an oppositely directed pH gradient and significantly reduced (p < 0.001) at low temperature in MDCK-MATE1, MDCK-OCT1/MATE1 and MDCK-OCT2/MATE1 cells. Co-administration of cimetidine or ritonavir decreased MATE1-mediated transport of emtricitabine by up to 42 and 39%, respectively (p < 0.01) and augmented intracellular accumulation of emtricitabine (p < 0.05). 3. We demonstrate emtricitabine as a substrate of MATE1 and suggest that MATE1 might cause DDI between emtricitabine and other co-administrated drugs including antiretrovirals.

• MeSH
• buňky MDCK MeSH
• emtricitabin metabolismus   MeSH
• inhibitory reverzní transkriptasy metabolismus   MeSH
• P-glykoprotein metabolismus   MeSH
• proteiny přenášející organické kationty metabolismus   MeSH
• psi MeSH
• zvířata MeSH
• Check Tag
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Lamivudine is one of the antiretroviral drugs of choice for the prevention of mother-to-child transmission (MTCT) in HIV-positive women. In this study, we investigated the relevance of drug efflux transporters P-glycoprotein (P-gp) (MDR1 [ABCB1]), BCRP (ABCG2), MRP2 (ABCC2), and MATE1 (SLC47A1) for the transmembrane transport and transplacental transfer of lamivudine. We employed in vitro accumulation and transport experiments on MDCK cells overexpressing drug efflux transporters, in situ-perfused rat term placenta, and vesicular uptake in microvillous plasma membrane (MVM) vesicles isolated from human term placenta. MATE1 significantly accelerated lamivudine transport in MATE1-expressing MDCK cells, whereas no transporter-driven efflux of lamivudine was observed in MDCK-MDR1, MDCK-MRP2, and MDCK-BCRP monolayers. MATE1-mediated efflux of lamivudine appeared to be a low-affinity process (apparent Km of 4.21 mM and Vmax of 5.18 nmol/mg protein/min in MDCK-MATE1 cells). Consistent with in vitro transport studies, the transplacental clearance of lamivudine was not affected by P-gp, BCRP, or MRP2. However, lamivudine transfer across dually perfused rat placenta and the uptake of lamivudine into human placental MVM vesicles revealed pH dependency, indicating possible involvement of MATE1 in the fetal-to-maternal efflux of the drug. To conclude, placental transport of lamivudine does not seem to be affected by P-gp, MRP2, or BCRP, but a pH-dependent mechanism mediates transport of lamivudine in the fetal-to-maternal direction. We suggest that MATE1 might be, at least partly, responsible for this transport.

• MeSH
• ABC transportéry metabolismus   MeSH
• biologický transport fyziologie   MeSH
• buněčné linie MeSH
• buňky MDCK MeSH
• krysa rodu rattus MeSH
• lamivudin metabolismus   MeSH
• lidé MeSH
• P-glykoproteiny metabolismus   MeSH
• placenta metabolismus   MeSH
• potkani Wistar MeSH
• proteiny přenášející organické kationty metabolismus   MeSH
• proteiny spojené s mnohočetnou rezistencí k lékům metabolismus   MeSH
• psi MeSH
• těhotenství MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• psi MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

In vivo metabolism of the radiolabelled receptor-specific peptides has been described; however, information regarding the pharmacokinetic behaviour of the degradation products within the body is very scarce. The present study was designed to obtain new knowledge on the disposition and elimination of low-molecular radiometabolites of receptor-specific peptides in the organism and to reveal the potential involvement of selected membrane transport mechanisms in the cellular uptake of radiometabolites, especially in the kidney. The study compared pharmacokinetics of two radiometabolites: a final metabolite of somatostatin analogues, (177)Lu-DOTA-DPhe, and a tripeptide metabolite of (177)Lu-DOTA-minigastrin 11, (177)Lu-DOTA-DGlu-Ala-Tyr. Their pharmacokinetics was compared with that of respective parent (177)Lu-radiopeptide. Both radiometabolites exhibited relative rapid clearing from most body tissues in rats in vivo along with predominant renal excretion. The long-term renal retention of the smaller radiometabolite (177)Lu-DOTA-DPhe was lower than that of (177)Lu-DOTA-DGlu-Ala-Tyr. An uptake of (177)Lu-DOTA-DPhe by human renal influx transporter organic cation transporter 2 was found in vitro in a cellular model. The study brings the first experimental data on the in vivo pharmacokinetics of radiometabolites of receptor-specific somatostatin and gastrin analogues. The found results may indicate a negative correlation between the degree of decomposition of the parent peptide chain and the renal retention of the metabolite.

• MeSH
• buňky MDCK MeSH
• fenylalanin analogy a deriváty   chemie   farmakokinetika   MeSH
• gastriny chemie   farmakokinetika   MeSH
• HeLa buňky MeSH
• komplexní sloučeniny chemie   farmakokinetika   MeSH
• krysa rodu rattus MeSH
• ledviny metabolismus   MeSH
• lidé MeSH
• oligopeptidy chemie   farmakokinetika   MeSH
• potkani Wistar MeSH
• proteiny přenášející organické kationty metabolismus   MeSH
• psi MeSH
• radiofarmaka chemie   farmakokinetika   MeSH
• somatostatin analogy a deriváty   chemie   MeSH
• tkáňová distribuce MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• mužské pohlaví MeSH
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Amphotericin B (AmB) is excreted via the renal excretion route. This excretion process may result in nephrotoxicity. However, relevant information on the precise renal excretion mechanisms is not available. The aim of the study was to analyze the possible interaction of AmB or its prodrug AmB deoxycholate (AmB-DOC) with the typical renal organic anion transporters (OATs) and organic cation transporters (OCTs), using cellular and organ models. The relevant transport systems were then investigated in terms of the drug-drug interactions of AmB-DOC with antivirals that might potentially be used concomitantly. To analyze the renal excretion mechanisms of [(3)H]AmB, perfused rat kidney was employed. HeLa and MDCK II cells transiently transfected with human OAT1 (hOAT1) or hOCT2 were used as the cellular models. A significant tubular secretion of AmB was demonstrated in the perfused rat kidney. The cellular studies performed confirmed the active transport of AmB into cells. AmB did not interact with hOAT1 but strongly inhibited hOCT2. In contrast, AmB-DOC inhibited both hOAT1 and hOCT2. However, [(3)H]AmB cellular uptake by hOAT1 and hOCT2 was not found. AmB-DOC interacted significantly with adefovir, tenofovir, and cidofovir in hOAT1-transfected cells at supratherapeutic concentrations. In conclusion, the significant potency of AmB and AmB-DOC for inhibiting the transporters was demonstrated in this study. The secretion of AmB in the renal tubules is likely not related to the transporters here, since the drug was not proven to be a substrate for them. Drug-drug interactions of AmB and the antivirals used in this study on the investigated transporters are not probable.

• MeSH
• amfotericin B metabolismus   MeSH
• antivirové látky metabolismus   MeSH
• buněčné linie MeSH
• fixní kombinace léků MeSH
• HeLa buňky MeSH
• krysa rodu rattus MeSH
• kyselina deoxycholová metabolismus   MeSH
• ledviny metabolismus   MeSH
• lékové interakce MeSH
• lidé MeSH
• potkani Wistar MeSH
• protein 1 přenášející organické anionty metabolismus   MeSH
• proteiny přenášející organické kationty metabolismus   MeSH
• psi MeSH
• teplota MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• mužské pohlaví MeSH
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

In our previous study, we described synchronized activity of organic cation transporter 3 (OCT3/SLC22A3) and multidrug and toxin extrusion 1 (MATE1/SLC47A1) transporter in the passage of organic cations across the rat placenta and the role of these transporters in fetal defense; in this study, we hypothesized that changes in placental levels of OCT3 and MATE1 throughout gestation might affect the fetal protection and detoxification. Using quantitative RT-PCR, Western blot analysis, and immunohistochemistry, we were able to detect Oct3/OCT3 and Mate1/MATE1 expression in the rat placenta as early as on Gestation Day (gd) 12 with increasing tendency toward the end of pregnancy. Comparing first versus third trimester human placenta, we observed stable expression of OCT1 and decreasing expression of OCT2 and OCT3 isoforms. Contrary to the current literature, we were able to detect also MATE1/MATE2 isoforms in the human placenta, however, with considerable inter- and intraindividual variability. Using infusion of 1-methyl-4-phenylpyridinium (MPP(+)), a substrate of OCT and MATE transporters, into pregnant dams, we investigated the protective function of the placenta against organic cations at different gds. The highest amount of MPP(+) reached the fetus on gd 12 while from gd 15 onward, maternal-to-fetal transport of MPP(+) decreased significantly. We conclude that increased expression of placental OCT3 and MATE1 along with general maturation of the placental tissues results in significantly lower transport of MPP(+) from mother to fetus. In contrast, decreasing expression of OCT3 and MATE1 in human placenta indicates these transporters may play a role in fetal protection preferentially at earlier stages of gestation.

• MeSH
• antiportéry metabolismus   MeSH
• imunohistochemie MeSH
• krysa rodu rattus MeSH
• lidé MeSH
• messenger RNA metabolismus   MeSH
• placenta metabolismus   MeSH
• plod metabolismus   MeSH
• potkani Wistar MeSH
• přenašeče organických aniontů nezávislé na sodíku metabolismus   MeSH
• proteiny přenášející organické kationty metabolismus   MeSH
• těhotenství MeSH
• vývoj plodu MeSH
• western blotting MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Mammal multidrug and toxin extrusion protein 1 (MATE 1) encoded by SLC47A1 gene was described in 2005 as an efflux transporter that mediates proton-coupled organic cation secretion. Shortly after, other isoforms (MATE2 and MATE2-K, both encoded by SLC47A2 gene) were identified. In the kidney and liver, MATEs work in concert with organic cation transporters (OCTs), together representing an eliminatory pathway for organic cations. Over 40 clinically used drugs and several endogenous compounds are known substrates or inhibitors of MATEs and the list is constantly growing. These transporters are supposed to modulate pharmacokinetics/toxicokinetics and to play a role in drug resistance and (patho)physiological processes. Drug-drug interactions on MATE transporters and polymorphisms in SLC47A genes may affect renal excretion of substrate drugs, such as metformin, resulting in inadequate pharmacotherapy or occurrence of toxic effects. Expression and function of MATEs in tissues other than kidney and liver remain to be elucidated.

• MeSH
• farmakokinetika * MeSH
• játra metabolismus   MeSH
• ledviny metabolismus   MeSH
• lékové interakce MeSH
• lidé MeSH
• polymorfismus genetický MeSH
• proteiny přenášející organické kationty genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

Renal hypouricemia (RHUC) is a heterogeneous inherited disorder characterized by impaired tubular uric acid (UA) transport with severe complications, such as acute kidney injury (AKI). Type 1 is caused by a loss-of-function mutation in the SLC22A12 gene (URAT1), type 2 in the SLC2A9 gene (GLUT9). This article describes three Czech families with RHUC type 1. The serum UA in the probands was 0.9, 1.1 and 0.5 mg/dl and expressed as an increase in the fractional excretion of UA (48, 43 and 39%). The sequencing analysis of SLC22A12 revealed three novel variants: p.G366R, p.T467M and a deletion p.L415_G417del. A detailed metabolic investigation in proband C for progressive visual failure supported suspicion of neuronal ceroid lipofuscinosis type 7 conditioned by the mutation in the MFSD8 gene. Functional studies showed significantly decreased urate uptake and a mis-localized URAT1 signal in p.G366R, p.L415_G417del and p.T467M. Furthermore, colocalization studies showed accumulation of URAT1 protein in the endoplasmic reticulum. The findings suggest that loss-of-function mutations cause RHUC via loss of UA absorption partly by protein misfolding. However, they do not necessarily lead to AKI and a possible genotype-phenotype correlation was not proposed. Furthermore, results confirm an uneven geographical and ethnic distribution of SLC22A12 variants; the p.L415_G417del mutation predominates in the Roma ethnic group in the Czech Republic.

• MeSH
• absorpce MeSH
• akutní poškození ledvin diagnóza   etiologie   genetika   MeSH
• alely * MeSH
• dítě MeSH
• dospělí MeSH
• endoplazmatické retikulum metabolismus   MeSH
• frekvence genu * MeSH
• heterozygot MeSH
• kyselina močová moč   MeSH
• lidé MeSH
• membránové transportní proteiny genetika   MeSH
• močové kameny komplikace   diagnóza   etnologie   genetika   MeSH
• mutace * MeSH
• neuronální ceroidlipofuscinózy diagnóza   etiologie   genetika   MeSH
• přenašeče organických aniontů genetika   metabolismus   MeSH
• proteiny přenášející organické kationty genetika   metabolismus   MeSH
• rodokmen MeSH
• Romové genetika   MeSH
• vrozené poruchy tubulárního transportu komplikace   diagnóza   etnologie   genetika   MeSH
• Xenopus MeSH
• zvířata MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH