Organic Anion Research Articles

Efficient separation of organic anions in beverages using aminosilane-functionalized capillary electrophoresis with contactless conductivity detection

BackgroundCapillary electrophoresis (CE) has the advantage of rapid anion analysis, when employing a reverse electroosmotic flow (EOF). The conventional CE method utilizes dynamic coatings with surfactants like cetyltrimethylammonium bromide (CTAB) in the run buffer to reverse the EOF. However, this method suffers from very slow equilibration leading to drifting effective migration times of the analyte anions, which adversely affects the identification and quantification of peaks. Permanent coating of the capillary surface may obviate this problem but has been relatively little explored. Thus, permanent capillary surface modification by the covalent binding of 3-aminopropyltriethoxysilane (APTES) was studied as an alternative. ResultsThis study investigates the effect of APTES concentration for surface functionalization on EOF mobility, separation efficiency, and reproducibility of anion separation. The performance data was complemented by X-ray photoelectron spectroscopy (XPS) and contact angle (CA) measurements. The XPS measurements showed that the coverage with APTES was dependent on its concentration in the coating solution. The XPS measurements correlated well with the EOF values determined for the capillaries tested. A standard mixture of 21 anions could be baseline separated within 10 min in the capillaries with lower EOF, but not in the capillary with the highest EOF as the residence time of the analytes was too short in this case. Compared to conventional dynamic coating with CTAB, APTES-functionalized capillaries provide faster equilibration and long-term EOF stability. The application of APTES-functionalized capillaries in analyzing different beverages demonstrates the precision, reliability, and specificity in determining organic anions, providing valuable insights of their compositions. SignificanceAPTES coating on capillaries provides a facile approach to achieve a permanent reversal of the stable EOF to determine anions. The control of the coverage via the concentration of the reagent solution allows the tailoring of the EOF to different needs, a faster EOF for less complex samples where resolution is not challenging, while a lower EOF for higher complex samples where the focus is on separation efficiency. This enhancement in efficiency and sensitivity has been applied to analyzing organic acids in several beverages.

In Situ Formed Organic Ion-Associate Liquid-Phase Microextraction without Centrifugation from Aqueous Solutions Using Thymol Blue and Estrogens

In this study, we present a method for ion-associated liquid phase (IALP) separation and concentration of analytes from an aqueous matrix into an IALP formed in situ by the charge neutralization reaction of organic cations and anions, without centrifugation. The effects of various factors on the extraction efficiency and other parameters are investigated, whereas no instrumental stirring, such as vortexing or ultrasonics, is required because the solvent (IALP) is formed in situ. The organic cation and anion used are ethylhexyloxypropylammonium and dodecyl sulfate, respectively. The developed in situ IALP microextraction method for phase separation without centrifugation is tested using the thymol blue dye and several endocrine disruptors. The tested endocrine disruptors (bisphenol A, 17β-estradiol, 17α-ethinylestradiol, and estrone) are analyzed via high-performance liquid chromatography/fluorescence detection, with respective detection limits of 0.02, 0.02, 0.02, and 0.4 μg L−1, and the corresponding enrichment factor ranging from 47 to 71. This IALP microextraction method can be used to separate and concentrate environmental water samples of different matrices. The employed IALP is fast and easy to use, enables an approximately 100-fold analyte concentration, and has a high affinity for estrogens, thus holding promise for the separation, concentration, and quantitation of diverse trace analytes.

Utilising Endogenous Biomarkers in Drug Development to Streamline the Assessment of Drug-Drug Interactions Mediated by Renal Transporters: A Pharmaceutical Industry Perspective.

The renal secretion of many drugs is facilitated by membrane transporters, including organic cation transporter 2, multidrug and toxin extrusion protein 1/2-K and organic anion transporters 1 and 3. Inhibition of these transporters can reduce renal excretion of drugs and thereby pose a safety risk. Assessing the risk of inhibition of these membrane transporters by investigational drugs remains a key focus in the evaluation of drug-drug interactions (DDIs). Current methods to predict DDI risk are based on generating in vitro data followed by a clinical assessment using a recommended exogenous probe substrate for the individual drug transporter. More recently, monitoring plasma-based and urine-based endogenous biomarkers to predict transporter-mediated DDIs in early phase I studies represents a promising approach to facilitate, improve and potentially avoid conventional clinical DDI studies. This perspective reviews the evidence for use of these endogenous biomarkers in the assessment of renal transporter-mediated DDI, evaluates how endogenous biomarkers may help to expand the DDI assessment toolkit and offers some potential knowledge gaps. A conceptual framework for assessment that may complement the current paradigm of predicting the potential for renal transporter-mediated DDIs is outlined.

The impact of chrysanthemi indici flos-enriched flavonoid part on the model of hyperuricemia based on inhibiting synthesis and promoting excretion of uric acid

Ethnopharmacological relevanceIn recent years, in addition to hypertension, hyperglycemia, and hyperlipidemia, the prevalence of hyperuricemia (HUA) has increased considerably. Being the fourth major health risk factor, HUA can affect the kidneys and cardiovascular system. Chrysanthemi Indici Flos is a flavonoid-containing traditional Chinese patent medicine that exhibits a uric acid (UA)-lowering effect. However, the mechanisms underlying Chrysanthemi Indici Flos-enriched flavonoid part (CYM.E) mediated alleviation of HUA remain unelucidated. Aim of the studyThis study aimed to elucidate the efficacy of CYM.E in preventing and treating HUA and its specific effects on UA-related transport proteins, to explore possible mechanism. MethodsThe buddleoside content in CYM.E was determined through high-performance liquid chromatography. HUA was induced in mice models using adenine and potassium oxonate. Subsequently, mice were administered 10 mg/kg allopurinol, and 30, 60, and 90 mg/kg CYM.E to evaluate the effects of CYM.E on the of HUA mice model. Herein, plasma uric acid (UA), creatinine (CR), blood urea nitrogen (BUN), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-c), and low-density lipoprotein cholesterol (LDL-c) contents, along with serum alanine aminotransferase (ALT), and aspartate aminotransferase (AST) activities were measured. Additionally, xanthine oxidase (XOD) and adenosine deaminase (ADA) activities in the liver were determined. The histomorphologies of the liver and kidney tissues were examined through hematoxylin and eosin staining. The messenger RNA (mRNA) expression of facilitated glucose transporter 9 (GLUT9), organic anion transporter (OAT)1, OAT3, and adenosine triphosphate binding cassette subfamily G2 (ABCG2) in the kidney was assessed by real-time quantitative polymerase chain reaction. Furthermore, the expression of urate transporter 1 (URAT1), GLUT9, OAT1, and OAT3 in the kidney, OAT4, and ABCG2 proteins was determined by immunohistochemistry and western blotting. ResultsThe buddleoside content in CYM.E was approximately 32.77%. CYM.E improved body weight and autonomous activity in HUA mice. Additionally, it reduced plasma UA, BUN, and CR levels and serum ALT and AST activities, thus improving hepatic and renal functions, which further reduced the plasma UA content. CYM.E reduced histopathological damage to the kidneys. Furthermore, it lowered plasma TC, TG, and LDL-c levels, thereby improving lipid metabolism disorder. CYM.E administration inhibited hepatic XOD and ADA activities and reduced the mRNA expression of renal GLUT9. CYM.E inhibited the protein expression of renal URAT1, GLUT9, and OAT4, and increased the mRNA and protein expression of renal OAT1, OAT3, and ABCG2. Altogether, these results show that CYM.E could inhibit the production and promote reabsorption of UA and its excretion.

Expression of hepatic genes involved in bile acid metabolism in dairy cows with fatty liver

Bile acids are cholesterol-derived molecules that are primarily produced in the liver. In nonruminants with fatty liver, overproduction of bile acids is associated with liver injury. During the transition period, fatty liver is a metabolic disorder that can affect up to 50% of high-producing dairy cows. The purpose of this study was to provide a comprehensive evaluation on hepatic bile acid metabolism in dairy cows with fatty liver by assessing expression changes of genes involved in bile acid synthesis, export and uptake. The serum activities of aspartate aminotransferase, alanine aminotransferase and glutamate dehydrogenase and concentration of total bile acids were all greater, whereas serum concentration of total cholesterol was lower in cows with fatty liver than in healthy cows. Content of total bile acids was higher but total cholesterol was slightly lower in liver tissues from fatty liver cows than from healthy cows. The hepatic mRNA abundance of cholesterol 7a-hydroxylase (CYP7A1), hydroxy-delta-5-steroid dehydrogenase, 3 β- and steroid delta-isomerase 7 (HSD3B7) and sterol 12α-hydroxylase (CYP8B1), enzymes involved in the classic pathway of bile acid synthesis, was higher in fatty liver cows than in healthy cows. Compared with healthy cows, the hepatic mRNA abundance of alternative bile acid synthesis pathway-related genes sterol 27-hydroxylase (CYP27A1) and oxysterol 7α-hydroxylase (CYP7B1) did not differ in cows with fatty liver. The protein and mRNA abundance of bile acid transporter bile salt efflux pump (BSEP) were lower in the liver of dairy cow with fatty liver. Compared with healthy cows, the hepatic mRNA abundance of bile acid transporters solute carrier family 51 subunit α (SLC51A), ATP binding cassette subfamily C member 1 (ABCC1) and 3 (ABCC3) was greater in cows with fatty liver, whereas the solute carrier family 51 subunit β (SLC51B) did not differ. The expression of genes involved in bile acid uptake, including solute carrier family 10 member 1 (NTCP), solute carrier organic anion transporter family member 1A2 (SLCO1A2) and 2B1 (SLCO2B1) was upregulated in dairy cows with fatty liver. Furthermore, the hepatic protein and mRNA abundance of bile acid metabolism regulators farnesoid X receptor (FXR) and small heterodimer partner (SHP) were lower in cows with fatty liver than in healthy cows. Overall, these data suggest that inhibition of FXR signaling pathway may lead to the increased bile acid synthesis and uptake and decreased secretion of bile acids from hepatocytes to the bile, which elevates hepatic bile acids content in dairy cows with fatty liver. As the hepatotoxicity of bile acids has been demonstrated on nonruminant hepatocytes, it is likely that the liver injury is induced by increased hepatic bile acids content in dairy cows with fatty liver.

Transporter Protein Expression of Corneal Epithelium in Rabbit and Porcine: Evaluation of Models for Ocular Drug Transport Study.

The transcorneal route is the main entry route for drugs to the intraocular parts, after topical administration. The outer surface, the corneal epithelium (CE), forms the rate-limiting barrier for drug permeability. Information about the role and protein expression of drug and amino acid transporter proteins in the CE is sparse and lacking. The aim of our study was to characterize transporter protein expression in rabbit and porcine CE to better understand potential drug and nutrient absorption after topical administration. Proteins, mainly Abc and Slc transporters, were characterized with quantitative targeted absolute proteomics and global untargeted proteomics methods. In the rabbit CE, 24 of 48 proteins were detected in the targeted approach, and 21 of these were quantified. In the porcine CE, 26 of 58 proteins were detected in the targeted approach, and 20 of these were quantified. Among these, 15 proteins were quantified in both animals: 4f2hc (Slc3a2), Aqp0, Asct1 (Slc1a4), Asct2 (Slc1a5), Glut1 (Slc2a1), Hmit (Slc2a13), Insr, Lat1 (Slc7a5), Mct1 (Slc16a1), Mct2 (Slc16a7), Mct4 (Slc16a3), Mrp 4 (Abcc4), Na+/K+-ATPase, Oatp3a1 (Slco3a1), and Snat2 (Slc38a2). Overall, the global proteomics results supported the targeted proteomics results. Organic anion transporting polypeptide Oatp3a1 was detected and quantified for the first time in both rabbit (1.4 ± 0.4 fmol/cm2) and porcine (11.1 ± 5.3 fmol/cm2) CE. High expression levels were observed for L-type amino acid transporter, Lat1, which was quantified with newly selected extracellular domain peptides in rabbit (48.9 ± 11.8 fmol/cm2) and porcine (37.6 ± 11.5 fmol/cm2) CE. The knowledge of transporter protein expression in ocular barriers is a key factor in the successful design of new ocular drugs, pharmacokinetic modeling, understanding ocular diseases, and the translation to human.

The impact of SLCO1B1 single nucleotide polymorphism and non-genetic factors on statin-induced myopathy

Abstract Funding Acknowledgements None. Background Statins, also known as HMG CoA Reductase Inhibitors, are a class of drugs considered the drug of choice for treating hypercholesterolemia. Statins are well tolerated; however, they may cause severe myopathy in 20% to 30% of patients, due to the individual variation regarding its efficacy and related adverse effects. Of these, comes the Single Nucleotide Polymorphism (SNP) T521C of the SLCO1B1 gene that encodes the protein involved in the trafficking of statins from the blood to hepatocytes which is called Organic Anion Transport Protein 1B1 (OATP1B1). The T521C single nucleotide polymorphism (SNP) results in a substitute of valine with alanine resulting in a decreased or lack of functional protein. Purpose The aim is to determine the frequency of the high-risk C allele and to define its impact on statin-induced myopathy in Syrian patients on statins. In addition to the non-genetic factors that may affect the ability to develop statin-induced myopathy. Methods This was an observational case-control study that had ethical approval from Damascus University (No.433/ 2020). The case group included 44 patients on statins who experienced myopathy, 18 patients who had increased creatinine kinase levels (CK), and 26 patients with normal CK levels, while the control group encompassed 56 patients who were taking statins and had no muscular adverse events. The DNA was extracted from each sample and then genotyped using standard sequencing of specific PCR products using a specific pair of primers. Results The age of patients in the case arm ranged between 27 and 84 years with an average ± SD of (58.2 ± 12.7 years), 70% of them were males. In comparison with (53.34 ± 12.4 years) in the control arm, 66% of them were males without a statistically significant differences (p=0.672, 0.057) respectively. The statin type and dose have a statistically non-significant effect, the average statin dose in the case arm and the control arm was 26.02 mg and 31.27 mg respectively (p=0.072). While the statin type treatment varied as 59% used atorvastatin and 39% used rosuvastatin in the case group compared with 71% used atorvastatin and 27% used rosuvastatin in the control group, without a statistically significant difference (p=0.252). The frequency of the C allele reaches 19.3% and is distributed in three genotypes: wild-type TT (68%), heterozygote TC (25%), and homozygote CC (7%) in the case arm, while it does not exceed 8% in the control arm with the absence of the CC genotype. Only a statistically significant difference was found in the frequency of the CC genotype between these two groups (p=0.047). Conclusion Our study is the first to identify the frequency of the 521T>C SNP of the SLCO1B1 gene in Syrian patients taking statins. Our data reveals a high prevalence of risk allele C in the patients who suffer from statin-induced myopathy with a statically significant difference from the control arm (p=0.026).

Endoplasmic reticulum transporter OAT2 regulates drug metabolism and interaction

Xenobiotic metabolic reactions in the hepatocyte endoplasmic reticulum (ER) including UDP-glucuronosyltransferase and carboxylesterase play central roles in the detoxification of medical agents with small- and medium-sized molecules. Although the catalytic sites of these enzymes exist inside of ER, the molecular mechanism for membrane permeation in the ER remains enigmatic. Here, we investigated that organic anion transporter 2 (OAT2) regulates the detoxification reactions of xenobiotic agents including anti-cancer capecitabine and antiviral zidovudine, via the permeation process across the ER membrane in the liver. Pharmacokinetic studies in patients with colorectal cancer revealed that the half-lives of capecitabine in rs2270860 (1324C > T) variants was 1.4 times higher than that in the C/C variants. Moreover, the hydrolysis of capecitabine to 5′-deoxy-5-fluorocytidine in primary cultured human hepatocytes was reduced by OAT2 inhibitor ketoprofen, whereas capecitabine hydrolysis directly assessed in human liver microsomes were not affected. The immunostaining of OAT2 was merged with ER marker calnexin in human liver periportal zone. These results suggested that OAT2 is involved in distribution of capecitabine into ER. Furthermore, we clarified that OAT2 plays an essential role in drug-drug interactions between zidovudine and valproic acid, leading to the alteration in zidovudine exposure to the body. Our findings contribute to mechanistically understanding medical agent detoxification, shedding light on the ER membrane permeation process as xenobiotic metabolic machinery to improve chemical changes in hydrophilic compounds.

Mechanism of flavonoids in the treatment of gouty arthritis (Review).

The present review expounds the advancements in the application and mechanisms of flavonoids in gouty arthritis, highlighting their significance in managing the disease. Gouty arthritis is among the most common and severe inflammatory diseases, caused by hyperuricemia and the deposition of sodium urate crystals in the joints and surrounding tissues, posing a serious threat to human life and health. Flavonoids, extracted from various herbs, have attracted significant attention due to their efficacy in improving gouty arthritis. The present study systematically reviews the in vivo studies and in vitro animal studies on flavonoids from herbal medicines for the treatment of gouty arthritis that have been previously published in the PubMed, ScienceDirect, Google Scholar and China National Knowledge Infrastructure databases between 2000 and 2023. The review of the literature indicated that flavonoids can improve gouty arthritis through multiple mechanisms. These include lowering xanthine oxidase activity, inhibiting uric acid (UA) synthesis, regulating UA transporters to promote UA excretion, reducing the inflammatory response and improving oxidative stress. These mechanisms predominantly involve regulating the NOD‑like receptor 3 inflammasome, the Toll‑like receptor 4/myeloid differentiation factor 88/nuclear factor‑κB signaling pathway, and the levels of UA transporter proteins, namely recombinant urate transporter 1, glucose transporter 9, organic anion transporter (OAT)1 and OAT3. Various flavonoids used in traditional Chinese medicine hold therapeutic promise for gouty arthritis and are anticipated to pave the way for novel pharmaceuticals and clinical applications.

Evaluation of 14 PFAS for permeability and organic anion transporter interactions: Implications for renal clearance in humans

Per- and polyfluoroalkyl substances (PFAS) encompass a diverse group of synthetic fluorinated chemicals known to elicit adverse health effects in animals and humans. However, only a few studies investigated the mechanisms underlying clearance of PFAS. Herein, the relevance of human renal transporters and permeability to clearance and bioaccumulation for 14 PFAS containing three to eleven perfluorinated carbon atoms (ηpfc = 3–11) and several functional head-groups was investigated. Apparent permeabilities and interactions with human transporters were measured using in vitro cell-based assays, including the MDCK-LE cell line, and HEK293 stable transfected cell lines expressing organic anion transporter (OAT) 1–4 and organic cation transporter (OCT) 2. The results generated align with the Extended Clearance Classification System (ECCS), affirming that permeability, molecular weight, and ionization serve as robust predictors of clearance and renal transporter engagement. Notably, PFAS with low permeability (ECCS 3A and 3B) exhibited substantial substrate activity for OAT1 and OAT3, indicative of active renal secretion. Furthermore, we highlight the potential contribution of OAT4-mediated reabsorption to the renal clearance of PFAS with short ηpfc, such as perfluorohexane sulfonate (PFHxS). Our data advance our mechanistic understanding of renal clearance of PFAS in humans, provide useful input parameters for toxicokinetic models, and have broad implications for toxicological evaluation and regulatory considerations.

#3023 Dietary protein intake modulates the tubular handling of the uremic retention solute indoxyl sulfate

Abstract Background and Aims Nutritional intervention constitutes a key part of the clinical management of individuals with chronic kidney disease (CKD). The gut emerged as an important source of uremic retention solutes, including indoxyl sulfate, p-cresyl sulfate and TMAO among the others. Indoxyl sulfate (IS) is produced through the gut microbial fermentation of tryptophan into indole and its conversion into indoxyl sulfate in the liver. Previous authors hypothesised that higher amounts of gut microbial metabolites can be sensed by kidney's proximal tubule cells through the use of receptors and signaling pathways. Particular evidence points to the involvement of kidney Organic Anion Transporters’(OATs') in controlling the gut-kidney communication. According to the so-called remote sensing hypothesis, kidney tubular cells respond to uremic toxins plasma fluctuations altering the activity of OAT1. Few studies have investigated whether in CKD the protein content in the diet affects gut generation, plasma retention and excretion mechanisms of indolic uremic toxins including kidney cells OAT1 expression. Method Eighteen male Sprague-Dawley rats (Janvier, France) aged 7-8 weeks and weighing between 270 and 388 g were randomly assigned to a low protein (LP) diet (n = 10) or a high protein (HP) diet (n = 8) after undergoing a 5/6 nephrectomy to develop CKD. For each diet, a sham-operated control group (n = 7 and n = 8 correspondingly) was used. After 7 weeks, urine was collected, and 8 weeks after the disease was induced, euthanasia was performed. Samples of kidney and blood were taken. mRNA and protein expression of OAT1 were sought via qPCR and Western blot. Forty patients with CKD were recruited in a cross-sectional study investigating eating habits and uremic toxins levels. Eating habits were searched via a food diary. Protein and energy intake were therefore calculated. Blood and 48 h-urine were collected. Blood creatinine and urea were determined with standard laboratory techniques. Total plasmatic and urinary IS concentrations were measured using LC-MS/MS. The fractional excretion (FE) i.e. the percentage of IS excreted relatively to the kidney filtered load, was calculated to assess IS remote sensing. Results Rats with chronic kidney disease (CKD) had considerably higher plasmatic levels of IS (p < .001) than sham rats. Rats with CKD on an HP diet, however, did not differ in plasma IS from rats fed an LP diet (p = .63). On the other hand, CKD rats fed an HP diet showed a substantial rise in 24-hour urinary IS (p < .001). The FE of IS was significantly higher (p = .005) in CKD rats on a HP diet and correlated with 24 h-urinary IS (Spearman r = .51, p value=.03) and with protein intake (Spearman r = .52, p value=.03) in CKD rats. OAT1 mRNA and protein expression was significantly higher in CKD rats given a HP diet (p = .025 and p = .009, respectively). By dividing the CKD patients into two groups by the median of protein intake, the FE of IS was significantly higher (p = .018) in the patients consuming a larger portion of proteins. Conclusion A diet higher in protein content in 5/6 nephrectomized CKD rats as well as in CKD patients likely leads to an increased production of indole in the colon. This results in increased IS fractional excretion but unchanged IS plasma retention. These findings offer more evidence for the mechanisms behind the remote sensing and signaling of uremic toxins derived from indole. In summary, a low-protein diet is still advised for people with chronic kidney disease.

Two novel in vitro assays to screen chemicals for their capacity to inhibit thyroid hormone transmembrane transporter proteins OATP1C1 and OAT4

Early brain development depends on adequate transport of thyroid hormones (THs) from the maternal circulation to the fetus. To reach the fetal brain, THs have to cross several physiological barriers, including the placenta, blood–brain-barrier and blood–cerebrospinal fluid-barrier. Transport across these barriers is facilitated by thyroid hormone transmembrane transporters (THTMTs). Some endocrine disrupting chemicals (EDCs) can interfere with the transport of THs by THTMTs. To screen chemicals for their capacity to disrupt THTMT facilitated TH transport, in vitro screening assays are required. In this study, we developed assays for two THTMTs, organic anion transporter polypeptide 1C1 (OATP1C1) and organic anion transporter 4 (OAT4), both known to play a role in the transport of THs across barriers. We used overexpressing cell models for both OATP1C1 and OAT4, which showed an increased uptake of radiolabeled T4 compared to control cell lines. Using these models, we screened various reference and environmental chemicals for their ability to inhibit T4 uptake by OATP1C1 and OAT4. Tetrabromobisphenol A (TBBPA) was identified as an OATP1C1 inhibitor, more potent than any of the reference chemicals tested. Additionally perfluorooctanesulfonic acid (PFOS), perfluoroctanic acid (PFOA), pentachlorophenol and quercetin were identified as OATP1C1 inhibitors in a similar range of potency to the reference chemicals tested. Bromosulfophthalein, TBBPA, PFOA and PFOS were identified as potent OAT4 inhibitors. These results demonstrate that EDCs commonly found in our environment can disrupt TH transport by THTMTs, and contribute to the identification of molecular mechanisms underlying TH system disruption chemicals.

The Renin-Angiotensin System Involvement in Cisplatin-Induced Nephrotoxicity: An Overview of Physiological and Pathological Mechanisms-A Systematic Review.

Cisplatin (CDDP) is a highly potent chemotherapy drug. But its nephrotoxicity poses a significant limitation to its use. The renin-angiotensin system (RAS) has been proposed to play a role in drug-induced nephrotoxicity. This systematic review (SR) sought to identify the link between CDDP-induced nephrotoxicity and the RAS pathway. In this SR, relevant keywords were employed to explore databases such as PubMed (MEDLINE), Scopus (Elsevier), and Institute for Scientific Information (ISI) Web of Science up to October 2023. Nine studies were selected based on predefined inclusion/exclusion criteria. The findings support the involvement of the RAS in the CDDP-induced nephrotoxicity model, along with the activation of inflammatory mediators, lipid peroxidation, and changes in markers of kidney tissue damage. Furthermore, physiology and pathology of RAS-related interventions in CDDP-induced nephrotoxicity models have involved the factors such as human organic cation transporter 2 (hOCT2), organic anion transporting polypeptides 1B1 (OATP1B1) and 1B3, kallikrein-kinin system, and bradykinin receptors. CDDP-induced nephrotoxicity has been found to be substantially influenced by both classic and nonclassic RAS axes. Angiotensin II exacerbates renal damage induced by CDDP. Conversely, inhibiting the pressor arm of RAS in males mitigates this damage. However, activation of the renal vasodepressor arm of RAS exacerbates CDDP-induced nephrotoxicity in females. These findings underscore gender differences in renal function and response to RAS-related interventions in the presence of CDDP. This SR provides insights into both beneficial and adverse interventions associated with RAS in the CDDP-induced nephrotoxicity, offering valuable considerations for researchers and clinicians.

Preparation of a class of cucurbit[6]uril-light rare-earth-based supramolecular assemblies and its efficient detection of chloramphenicol

By introducing 4,4′-naphthalenedisulfonic acid (4,4′-H2BPs) as a structure-induced agent, four novel cucurbit[6]uril-based supramolecular assemblies have been successfully prepared in the cucurbit[6]uril (Q[6]) system with light rare-earth elements (La3+, Ce3+, Pr3+, Nd3+) under hydrothermal conditions. Crystal structure analysis shows that the assemblies 1 (La3+), 2 (Ce3+), 3 (Pr3+) are isomorphism 3D frameworks, where Q[6] can directly coordinate with light rare-earth metal ions to form 1D −Ln(III)- Q[6]-Ln(III)- chains, while the 4 (Nd3+) presents 3D structures stacking by the unit of Q[6]@Nd3+@Q[6]@Nd3+@Q[6], respectively. In these structures, 4,4′-H2BPs ligands all can act as an organic counter anion and bridging via the outer-surface interaction of cucurbit[n]uril (OSIQ) in the system, which is the main driving force from low-dimensional to high-dimensional. Meanwhile, the fluorescence sensing performance of the two assemblies for antibiotics was investigated, and the results showed that assembly 1 could be used as a promising fluorescent sensor material to detect chloramphenicol (CAP).

Identification of Hyperuricemia Alleviating Peptides from Yellow Tuna Thunnus albacares.

The development of food-derived antihyperuricemic substances is important for alleviating hyperuricemia (HUA) and associated inflammation. Here, novel peptides fromThunnus albacares (TAP) with strong antihyperuricemic activity were prepared. TAP was prepared by alkaline protease (molecular weight <1000 Da), with an IC50 value of xanthine oxidase inhibitory activity of 2.498 mg/mL, and 5 mg/mL TAP could reduce uric acid (UA) by 33.62% in human kidney-2 (HK-2) cells (P < 0.01). Mice were fed a high-purine diet and injected with potassium oxonate to induce HUA. Oral administration of TAP (600 mg/kg/d) reduced serum UA significantly by 42.22% and increased urine UA by 79.02% (P < 0.01) via regulating urate transporters GLUT9, organic anion transporter 1, and ATP-binding cassette subfamily G2. Meantime, TAP exhibited hepatoprotective and nephroprotective effects, according to histological analysis. Besides, HUA mice treated with TAP showed anti-inflammatory activity by decreasing the levels of toll-like receptor 4, nuclear factors-κB p65, NLRP3, ASC, and Caspase-1 in the kidneys (P < 0.01). According to serum non-targeted metabolomics, 91 differential metabolites between the MC and TAP groups were identified, and purine metabolism was considered to be the main pathway for TAP alleviating HUA. In a word, TAP exhibited strong antihyperuricemic activity both in vitro and in vivo.

Evaluation of the Clinical Drug-Drug Interaction Potential of Pritelivir on Transporters and CYP450 Enzymes Using a Cocktail Approach.

Pritelivir is a novel viral helicase-primase inhibitor active against herpes simplex virus. In vitro drug-drug interaction studies indicated that pritelivir has the potential for clinically relevant interactions on the cytochrome P450 (CYP) enzymes 2C8, 2C9, 3A4, and 2B6, and intestinal uptake transporter organic anion transporting polypeptide (OATP) 2B1 and efflux transporter breast cancer resistance protein (BCRP). This was evaluated in 2 clinical trials. In 1 trial the substrates flurbiprofen (CYP2C9), bupropion (CYP2B6), and midazolam (CYP3A4) were administered simultaneously as part of the Geneva cocktail, while the substrate celiprolol (OAPT2B1) was administered separately. In another trial, the substrates repaglinide (CYP2C8) and rosuvastatin (BCRP) were administered separately. Exposure parameters of the substrates and their metabolites (flurbiprofen and bupropion only) were compared after administration with or without pritelivir under therapeutic concentrations. The results of these trials indicated that pritelivir has no clinically relevant effect on the exposure of substrates for the intestinal uptake transporter OATP2B1 and the CYP enzymes 3A4, 2B6, 2C9, and 2C8, and has a weak inhibitory effect on the intestinal efflux transporter BCRP. In summary, the results suggest that pritelivir has a low drug-drug interaction potential.

Interactions of oleanane pentacyclic triterpenoids with human organic anion transporting polypeptide 1B1 and 1B3

Oleanane pentacyclic triterpenoids have been widely used in clinical practice. However, studies on their interactions with hepatic transporters remain limited. In this study, we systematically investigated the inhibitory effects of 14 oleanane pentacyclic triterpenoids on organic anion transporting polypeptide 1B1 and 1B3 (OATP1B1 and OATP1B3), two liver-specific uptake transporters. Through fluorescence-based cellular uptake assays, we identified three potent OATP1B1 inhibitors (saikosaponin B1, saikosaponin A and 18β-glycyrrhetinic acid) and five potent OATP1B3 inhibitors (echinocystic acid, 3-oxo-16α-hydroxy-olean-12-en-28β-oic acid, chikusetsu saponin IVa, saikosaponin B1 and 18β-glycyrrhetinic acid). Structural analysis revealed that free oleanane triterpenoids inhibited OATP1B1/1B3 more potently than triterpene glycosides. Despite their similar structures, 18β-glycyrrhetinic acid exhibited much stronger inhibition on OATP1B1/1B3 than 18α-glycyrrhetinic acid, while both were substrates of OATP1B3. Interestingly, OATP1B3 overexpression significantly increased reactive oxygen species (ROS) levels in HepG2 cells after treatment with 18β-glycyrrhetinic acid. To conclude, this study highlights the potential interactions of oleanane pentacyclic triterpenoids with OATP1B1/1B3, and provides novel insights into the anti-cancer activity of 18β-glycyrrhetinic acid.

Elucidating nonlinear pharmacokinetics of telmisartan: Integration of target-mediated drug disposition and OATP1B3-mediated hepatic uptake in a physiologically based model.

Telmisartan, a selective inhibitor of angiotensin II receptor type 1 (AT1), demonstrates nonlinear pharmacokinetics (PK) when orally administered in ascending doses to healthy volunteers, but the underlying mechanisms remain unclear. This study presents a physiologically based pharmacokinetic model integrated with target-mediated drug disposition (TMDD-PBPK model) to explore the mechanism of its nonlinear PK. We employed the Cluster-Gauss Newton method for top-down analysis, estimating the invivo Km,OATP1B3 (Michaelis-Menten constant for telmisartan hepatic uptake via Organic Anion Transporting Polypeptide 1B3) to be 2.0-5.7 nM. This range is significantly lower than the reported invitro value of 810 nM, obtained in 0.3% human serum albumin (HSA) conditions. Further validation was achieved through invitro assessment in plated human hepatocytes with 4.5% HSA, showing a Km of 4.5 nM. These results underscore the importance of albumin-mediated uptake effect for the hepatic uptake of telmisartan. Our TMDD-PBPK model, developed through a "middle-out" approach, underwent sensitivity analysis to identify key factors in the nonlinear PK of telmisartan. We found that the nonlinearity in the area under the concentration-time curve (AUC) and/or maximum concentration (Cmax) of telmisartan is sensitive to Km,OATP1B3 across all dosages. Additionally, the dissociation constant (Kd) for telmisartan binding to the AT1 receptor, along with its receptor abundance, notably influences PK at lower doses (below 20 mg). In conclusion, the nonlinear PK of telmisartan appears primarily driven by hepatic uptake saturation across all dose ranges and by AT1-receptor binding saturation, notably at lower doses.

Mechanistic Account of Distinct Change in Organic Anion Transporting Polypeptide 1B (OATP1B) Substrate Pharmacokinetics during OATP1B-Mediated Drug-Drug Interactions Using Physiologically Based Pharmacokinetic Modeling.

The role of transporters in drug clearance is widely acknowledged, directly and indirectly by facilitating tissue/enzyme exposure. Through the latter, transporters also affect volume of distribution. Drug-drug interactions (DDIs) involving organic anion transporting polypeptides (OATPs) 1B1/1B3 and SLCO1B1 pharmacogenetics lead to altered pharmacokinetics of OATP1B substrates; however, several factors may confound direct interpretation of pharmacokinetic parameters from these clinical studies using noncompartmental analysis (NCA). A review of clinical data herein indicates a single dose of OATP1B inhibitor rifampin almost never leads to increased substrate half-life but often a decrease and that most clinical OATP1B substrates are CYP3A4 substrates and/or undergo enterohepatic cycling (EHC). Using hypothetically simple OATP1B substrate physiologically based pharmacokinetic (PBPK) models, simulated effect of rifampin differed from specific OATP1B inhibition due to short rifampin half-life causing dissipation of OATP1B inhibition over time combined with CYP3A4 induction. Calculated using simulated tissue data, volume of distribution indeed decreased with OATP1B inhibition and was expectedly limited to the contribution of liver volume. However, an apparent and counterintuitive effect of rifampin on volume greater than that on clearance resulted for CYP3A4 substrates using NCA. The effect of OATP1B inhibition and rifampin on OATP1B substrate models incorporating EHC plus or minus renal clearance was distinct compared with simpler models. Using PBPK models incorporating reversible lactone metabolism for clinical OATP1B substrates atorvastatin and pitavastatin, DDIs reporting decreased half-life with rifampin were reproduced. These simulations provide an explanation for the distinct change in OATP1B substrate pharmacokinetics observed in clinical studies, including changes in volume of distribution and additional mechanisms. SIGNIFICANCE STATEMENT: Transporters are involved in drug clearance and volume of distribution, and distinct changes in OATP1B substrate pharmacokinetics are observed with OATP1B inhibitor rifampin. Using hypothetical and validated PBPK models and simulations, this study addresses the limitations of single-dose rifampin and complicated clinical OATP1B substrate disposition in evaluating the pharmacokinetic parameters of OATP1B substrates during rifampin drug-drug interactions (DDIs). These models account for change in volume of distribution and identify additional mechanisms underlying apparent pharmacokinetic changes in OATP1B DDIs.

Can fertilization of potato (Solanum tuberosum L.) with potassium sulfate cause oxidative stress in the plants?

AbstractBackgroundPotatoes are regarded very prone to chloride toxicity, and the application of sulfate‐based potassium fertilizers is therefore recommended. However, in several studies, no significant differences between KCl and K2SO4 on tuber yield and starch concentration were found. In addition, plant shoots occasionally showed more pronounced stress symptoms after sulfate compared to chloride treatment.AimsThis study aimed to identify reasons for enhanced stress occurrence of potato plants after K2SO4 instead of KCl fertilization.MethodsWe conducted a pot experiment with the potato cultivar Marabel, which showed to be chloride‐resistant in our previous study, and applied 1 g K or 2 g K either as K2SO4 or KCl. Plant shoots were analyzed for nutrients, sugars, and antioxidative capacity shortly before start of flowering (intermediate harvest), and tubers were harvested at physiological maturity and their starch concentration and yield were determined.ResultsWith sulfate‐based K fertilization, the start of flowering and ripening as well as the achievement of physiological maturity occurred earlier than with KCl supply. However, the accelerated development of K2SO4‐treated plants did not affect shoot fresh and dry mass shortly before flowering and at maturity, showing similar values as in the KCl treatment. With 2 g K as K2SO4, the potato plants produced much larger and less than half the number of tubers compared to 2 g K as KCl, resulting in a significantly reduced tuber fresh mass. Tuber starch concentration as well as starch yield per plant were not significantly affected by the kind of K fertilization. In plant shoots shortly before flowering, calcium and magnesium concentrations were significantly decreased, combined with a significant increase in antioxidative capacity after application of 2 g K as K2SO4 compared to KCl. Sugar concentrations and contents in potato shoots at flowering were mostly unaffected by the kind of K fertilizer.ConclusionsStronger toxicity symptoms and growth inhibition after sulfate compared to chloride application, combined with a significant increase in antioxidative capacity, provide evidence for sulfate‐induced oxidative stress. A higher production of organic anions such as succinate may be involved in the stress reaction. This needs to be investigated in more detail in further studies.