Fast Metabolism Research Articles

CYP1A2 Genetic Variation, Coffee Intake, and Kidney Dysfunction

Caffeine is detoxified by cytochrome P450 1A2 (CYP1A2), and genetic variation in CYP1A2 impacts the rate of caffeine clearance. Factors that may modify the association between coffee intake and kidney disease remain unclear. To assess whether CYP1A2 genotype modifies the association between coffee intake and kidney dysfunction. The Hypertension and Ambulatory Recording Venetia Study (HARVEST) was a prospective cohort study of individuals with stage 1 hypertension in Italy; HARVEST began on April 1, 1990, and follow-up is ongoing. The current study used data from April 1, 1990, to June 30, 2006, with follow-up of approximately 10 years. Blood pressure and biochemical data were collected monthly during the first 3 months, then every 6 months thereafter. Data were analyzed from January 2019 to March 2019. Participants were screened and recruited from general practice clinics. The present study included 1180 untreated participants aged 18 to 45 years with stage 1 hypertension; those with nephropathy, diabetes, urinary tract infection, and cardiovascular disease were excluded. Coffee intake and CYP1A2 genotype rs762551 were exposures analyzed over a median follow-up of 7.5 (IQR, 3.1-10.9) years. Albuminuria (defined as an albumin level of ≥30 mg/24 h) and hyperfiltration (defined as an estimated glomerular filtration rate of ≥150 mL/min/1.73 m2) were the primary outcomes as indicators of kidney dysfunction. Among 1180 participants, genotyping, lifestyle questionnaires, and urine analysis data were obtained from 604 individuals (438 [72.5%] male) with a mean (SD) age of 33.3 (8.5) years and a mean (SD) body mass index (calculated as weight in kilograms divided by height in meters squared) of 25.4 (3.4). A total of 158 participants (26.2%) consumed less than 1 cup of coffee per day, 379 (62.7%) consumed 1 to 3 cups per day, and 67 (11.1%) consumed more than 3 cups per day. Genotype frequencies for rs762551 (260 participants [43.1%] with genotype AA, 247 participants [40.8%] with genotype AC, and 97 participants [16.1%] with genotype CC) did not differ between coffee intake categories. The level of risk of developing albuminuria, hyperfiltration, and hypertension, assessed by Cox regression and survival analyses, was not associated with coffee intake in the entire group or among fast metabolizers. The risks of albuminuria (adjusted hazard ratio [aHR], 2.74; 95% CI, 1.63-4.62; P < .001), hyperfiltration (aHR, 2.11; 95% CI, 1.17-3.80; P = .01), and hypertension (aHR, 2.81; 95% CI, 1.51-5.23; P = .001) increased significantly among slow metabolizers who consumed more than 3 cups per day. In this study, the risks of albuminuria, hyperfiltration, and hypertension increased with heavy coffee intake only among those with the AC and CC genotypes of CYP1A2 at rs762551 associated with slow caffeine metabolism, suggesting that caffeine may play a role in the development of kidney disease in susceptible individuals.

Pharmacokinetic Evaluation of New Drugs Using a Multi-Labelling Approach and PET Imaging: Application to a Drug Candidate with Potential Application in Neuromuscular Disorders.

The determination of pharmacokinetic properties of new chemical entities is a key step in the process of drug development. Positron emission tomography (PET) is an ideal technique to obtain both biodistribution and pharmacokinetic parameters of new compounds over a wide range of chemical modalities. Here, we use a multi-radionuclide/multi-position labelling approach to investigate distribution, elimination, and metabolism of a triazole-based FKBP12 ligand (AHK2) with potential application in neuromuscular disorders. Target engagement and stabilizing capacity of the drug candidate (AHK2) towards FKBP12-RyR was evaluated using competitive ligand binding and proximity ligation assays, respectively. Subsequently, AHK2 was labelled either with the positron emitter carbon-11 (11C) via 11C-methylation to yield both [11C]AHK2.1 and [11C]AHK2.2, or by palladium-catalysed reduction of the corresponding 5-iodotriazole derivative using 3H gas to yield [3H]AHK2. Metabolism was first investigated in vitro using liver microsomes. PET imaging studies in rats after intravenous (IV) administration at different doses (1 µg/Kg and 5 mg/Kg) were combined with determination of arterial blood time-activity curves (TACs) and analysis of plasma samples by high performance liquid chromatography (HPLC) to quantify radioactive metabolites. Arterial TACs were obtained in continuous mode by using an in-house developed system that enables extracorporeal blood circulation and continuous measurement of radioactivity in the blood. Pharmacokinetic parameters were determined by non-compartmental modelling of the TACs. In vitro studies indicate that AHK2 binds to FKBP12 at the rapamycin-binding pocket, presenting activity as a FKBP12/RyR stabilizer. [11C]AHK2.1, [11C]AHK2.2 and [3H]AHK2 could be obtained in overall non-decay corrected radiochemical yields of 14 ± 2%, 15 ± 2% and 0.05%, respectively. Molar activities were 60-110 GBq/µmol, 68-122 GBq/µmol and 0.4-0.5 GBq/μmol, respectively. In vitro results showed that oxidation of the thioether group into sulfoxide, demethylation of the CH3O-Ar residue and demethylation of -N(CH3)2 were the main metabolic pathways. Fast metabolism was observed in vivo. Pharmacokinetic parameters obtained from metabolite-corrected arterial blood TACs showed a short half-life (12.6 ± 3.3 min). Dynamic PET imaging showed elimination via urine when [11C]AHK2.2 was administered, probably reflecting the biodistribution of [11C]methanol as the major metabolite. Contrarily, accumulation in the gastrointestinal track was observed after administration of [11C]AKH2.1. AHK2 binds to FKBP12 at the rapamycin-binding pocket, presenting activity as a FKBP12/RyR stabilizer. Studies performed with the 3H- and 11C-labelled FKBP12/RyR stabilizer AHK2 confirm fast blood clearance, linear pharmacokinetics and rapid metabolism involving oxidation of the sulfide and amine moieties and oxidative demethylation of the CH3-O-Ar and tertiary amine groups as the main pathways. PET studies suggest that knowledge about metabolic pathways is paramount to interpret images.

Assessment of increase in the abundance of two hummingbird species in the last decade in Mexico City

Abstract Hummingbirds are nectarivorous birds with a very fast metabolism, which requires constant access to resources. In cities, resources have distinct abundances and availability from natural environments, which leads to the exclusion of some species. However, other species may increase in abundance within cities, causing a process of biotic homogenization. In this work we evaluated whether the abundance of five resident hummingbird species has increased in Mexico City over the last decade. Additionally, we evaluated whether these hummingbirds used feeders throughout the year. Finally, we determined the reproductive season of hummingbirds and evaluated whether it is longer in Mexico City than in non-urban locations. Our results indicate that during the last decade, the abundance of Berylline Hummingbird and Broad-billed Hummingbird has increased in Mexico City. Both species take advantage of the feeders throughout the year. This constant availability of resources has allowed both species to extend their breeding season, leading to constantly increasing abundance. One way to avoid biotic homogenization in cities is to implement conservation strategies that include variations in the availability and abundance of native floral resources such as pollinator gardens, rather than constantly available artificial resources like feeders.

A Low Tacrolimus Concentration-to-Dose Ratio Increases Calcineurin Inhibitor Nephrotoxicity and Cytomegalovirus Infection Risks in Kidney Transplant Recipients: A Single-Center Study in Japan

Tacrolimus (TAC) has several problems due to its narrow therapeutic window and variations pharmacokinetics and pharmacodynamics. Recently, several studies reported that TAC metabolism, defined by TAC blood trough concentration to dose (C/D) ratio, was associated with TAC toxicity. Reports on once-daily extended-release TAC (TAC-ER) are limited. The present study aimed to investigate the effect of the TAC metabolic rate on TAC-ER and compare TAC area under the curve (AUC) between fast and slow metabolizers. A total of 58 recipients were included in this study. The optimal cut-off value and time of the C/D ratio on TAC-ER for fast and slow metabolizers was determined using receiver operating characteristic curve analysis for biopsy-proven calcineurin inhibitor (CNI) nephrotoxicity. The optimal time to evaluate the C/D ratio was 1 month after kidney transplantation (KT) and the cut-off value was 0.9. The multivariate analysis for CNI nephrotoxicity risk showed that only TAC metabolism was associated with CNI nephrotoxicity (hazard ratio 10.60, P=.005, 95% CI 2.03-55.22). Cytomegalovirus infection occurred more frequently in fast metabolizers when the cut-off value of the C/D ratio was set to 0.9 at 3 months after KT (P=.04). The TAC C4, AUC2-8, was higher in fast metabolizers than in slow metabolizers (P < .01, P=.03, respectively). The study revealed that TAC fast metabolizers on TAC-ER may be classified as a high-risk group for CNI nephrotoxicity and cytomegalovirus infection. The result of TAC AUC supported the hypothesis that fast metabolizers tended to be overexposed to immunosuppressive agents early after oral administration.

Curcumin nanoparticles: physicochemical fabrication, characterization, antioxidant, enzyme inhibition, molecular docking and simulation studies.

Curcumin is an extensively studied natural compound due to its extensive biological applications. However, there are some drawbacks linked to this compound such as poor absorption, low water-solubility, quick systemic elimination, fast metabolism, poor pharmacokinetics, low bioavailability, low penetration targeting efficacy and low stability. To overcome these drawbacks, curcumin is encapsulated in nano-carriers. In the current studies, we synthesized nanoparticles of curcumin without using nanocarriers by different methods such as nano-suspension (Cur-NSM), sonication (Cur-SM) and anti-solvent precipitation (Cur-ASP) to enhance the solubility of curcumin in water. The prepared nanoparticles were characterized by FTIR, SEM and XRD analysis. These curcumin nanoparticles were screened for their solubilities in water, DPPH scavenging, amylase, α-glucosidase and β-glucosidase enzymatic activities. The particle size of nano-curcumin was found to be in the 47.4-98.7 nm range. The reduction in particle size of curcumin dramatically increases its solubility in water to 79.2 μg mL-1, whereas the solubility of curcumin is just 0.98 μg mL-1. Cur-ASP showed the highest free radical scavenging potential (48.84 ± 0.98%) which was comparable with standard BHT (50.48 ± 1.11%) at 75.0 μg mL-1. As well, Cur-ASP showed the highest inhibition of α-amylase (68.67 ± 1.02%), α-glucosidase (58.30 ± 0.52%), and β-glucosidase (64.80 ± 0.43%) at 100 μg mL-1 which is comparable with standard drug acarbose. The greater surface area of nanoparticles exposes the various groups of curcumin for blocking the binding sites of enzymes. This strategy may be helpful in designing curcumin as a potent therapeutic agent against diabetes mellitus. Further, the molecular interactions of curcumin with α-amylase, α-glucosidase, β-glucosidase, and polyphenol oxidase were assessed by analyzing the plausible binding modes of curcumin in the binding pocket of each receptor. The best binding mode of curcumin was used to make complexes with the target proteins and their stability was confirmed by 50 ns MD simulation.

Assessing hydroxylated polycyclic aromatic hydrocarbon (OHPAH) metabolites in bile of English sole (Parophrys vetulus) from Puget Sound, WA, USA by liquid chromatography/tandem mass spectrometry (LC-MS/MS)

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants that are widely monitored in marine biota from urbanized areas, due to their toxicity to aquatic organisms. Teleost fish can quickly metabolize PAHs into hydroxylated forms (OHPAHs) that, in some cases, are more toxic than the parent (unmetabolized) PAHs. But due to this fast metabolism, monitoring traditional parent PAHs in fish can cause underestimation on assessing PAH exposure. In addition, environmental levels of individual OHPAH metabolites are lacking in the literature worldwide. Therefore, we developed a rapid and accurate analytical method in which a number of individual OHPAHs metabolites are measured simultaneously in fish bile, via liquid chromatography coupled with tandem mass spectrometry, including low and high molecular weight mono- and diol-OHPAHs. We analyzed bile samples of 119 English sole (Parophrys vetulus) collected from 14 Puget Sound, WA, USA, sites, which has multiple sources of PAHs, including urban stormwater runoff, wastewater effluents, as well as an inactive creosote facility. The mean (± SD) biliary summed OHPAH (∑OHPAH) concentrations determined in English sole from urban, near-urban, and non-urban sites were 790 ± 1400 (n = 46), 310 ± 330 (n = 44) and 130 ± 200 (n = 29) ng/mL, respectively, with a maximum reaching 9400 ng/mL in a sample from an urban site. We compared these novel biliary OHPAH metabolite data with parent PAHs measured in stomach content of the same individual sole. Biliary ∑OHPAH concentrations were significantly correlated with the levels of ∑PAH in stomach content, however, with major differences in their distribution. We also demonstrated that biliary OHPAH metabolite data in English sole can potentially be used to distinguish different sampling sites due to a specific variety and intensity of PAH sources in the aquatic environment, which makes this a very important analytical approach for assessing PAH exposure in the environment.

Study of the activity of sunflower honey against a mixed microbial association isolated from bees with signs of dyspepsia in laboratory conditions

Beekeeping is one of the essential branches of agriculture in Ukraine, the main activity of which is aimed at breeding bees and obtaining honey and other products beneficial for human health. Maintaining the physiological state of bee colonies at the proper level is one of the essential tasks of veterinary medicine doctors and beekeepers. Compliance with veterinary and sanitary requirements at bee farms is the basis of preventing infectious pathologies in bee colonies. Since the body of insects has a fast metabolism, any infectious pathology quickly acquires a massive manifestation. One indicative symptom of infectious damage to the “gut” of bees is dyspepsia. Diarrhea, anorexia, and loss of productivity are observed in bees in this condition. The market of means to prevent such pathological manifestations in beekeeping is relatively narrow. The healing and favorable properties of honey, manifested in pain-relieving, antimicrobial and anti-inflammatory effects, have been known since ancient times. Sunflower honey differs from other types in a wide range of components, particularly phytoncides, which inhibit the growth of pathogenic microorganisms. Therefore, the main goal of the experiment was a laboratory study of the effect of different concentrations of sunflower honey sieve on the mixed microbial association isolated from bees with signs of dyspepsia. The activity of sunflower honey in laboratory conditions was studied by the disco-diffusion method in Petri dishes on MPA medium (meat-peptone agar). To obtain syrup from sunflower honey, sunflower honey was diluted with distilled water in a ratio of 1:1, working solutions were prepared from sunflower honey syrup in dilutions of 1:2, 1:4, 1:10, 1:100. The data analysis indicates the bacteriostatic activity of the syrup from sunflower honey in all studied concentrations concerning the mixed microbial association. Moreover, the largest diameter of the growth inhibition zone of the studied microorganisms was noted when the syrup from sunflower honey was diluted in a ratio of 1:10 (19.2 ± 0.42 mm). In turn, the antagonistic effect of the syrup from sunflower honey was observed in all dilutions concerning the mixed microbial association, where the largest diameter of the antagonism was 19.6 ± 0.27 mm when the disc was impregnated with the native working solution. Thus, it is promising to accumulate and identify a pure culture antagonist concerning a mixed culture of bacteria isolated during bee diarrhea to further create a pharmacological agent for preventing infectious pathologies of bees in unhealthy apiaries.

Associations of biomarkers for exposure to tobacco smoke with lung cancer risk in Korea.

Nicotine metabolite ratio (NMR) can be used to predict total nicotine clearance. However, it is unknown whether NMR could be used as a marker of lung cancer risk. To evaluate the blood metabolites of nicotine relating to the risk of developing lung cancer and investigate the combined effects of NMR and cigarette per day on the risk of lung cancer. Among the 1,054 eligible subjects from the Korean Cancer Prevention Study-II biobank cohort, those with cotinine values below 0 ng/ml were excluded. Slow and fast metabolizer groups were defined using the median value of the NMR, calculated with the control group data, as the cut-point. The multivariable Cox proportional hazard models demonstrated that, the fast metabolizer group had a significantly higher risk of lung cancer than the slow metabolizer group (Adjusted HR: 2.02, 95% CI: 1.32-3.10). Fast metabolizers who smoked more than 15 cigarettes per day had an even higher risk of lung cancer (Adjusted HR: 3.51, 95% CI: 1.96-6.29) than the slow metabolizers who smoked less than 15 cigarettes per day. In summary, the NMR may be an effective marker for estimating tobacco-related disease risks such as lung cancer.

Herramientas para un ajuste de dosis de tacrolimus más personalizado en el seguimiento de los pacientes con transplante renal. Fenotipo metabolizador según polimorfismos genéticos del CYP3A vs. el cociente concentración-dosis

Background and justificationThe strategy of the concentration–dose (C/D) approach and the different profiles of tacrolimus (Tac) according to the cytochrome P450 polymorphisms (CYPs) focus on the metabolism of Tac and are proposed as tools for the follow-up of transplant patients. The objective of this study is to analyse both strategies to confirm whether the stratification of patients according to the pharmacokinetic behaviour of C/D corresponds to the classification according to their CYP3A4/5 cluster metabolizer profile. Materials and methodsFour hundred and twenty-five kidney transplant patients who received Tac as immunosuppressive treatment have been included. The concentration/dose ratio (C/D) was used to divided patients in terciles and classify them according to their Tac metabolism rate (fast, intermediate, and slow). Based on CYP3A4 and A5 polymorphisms, patients were classified into three metabolizer groups: fast (CYP3A5*1 and CYP34A*1/*1 carriers), intermediate (CYP3A5*3/3 and CYP3A4*1/*1) and slow (CYP3A5*3/*3 and CYP3A4*22 carriers). ResultsWhen comparing patients included in each metabolizer group according to C/D ratio, 47% (65/139) of the fast metabolizers, 85% (125/146) of the intermediate and only 12% (17/140) of the slow also fitted in the homonym genotype group. Statistically lower Tac concentrations were observed in the fast metabolizers group and higher Tac concentrations in the slow metabolizers when compared with the intermediate group both in C/D ratio and polymorphisms criteria. High metabolizers required approximately 60% more Tac doses than intermediates throughout follow-up, while poor metabolizers required approximately 20% fewer doses than intermediates. Fast metabolizers classified by both criteria presented a higher percentage of times with sub-therapeutic blood Tac concentration values. ConclusionDetermination of the metabolizer phenotype according to CYP polymorphisms or the C/D ratio allows patients to be distinguished according to their exposure to Tac. Probably the combination of both classification criteria would be a good tool for managing Tac dosage for transplant patients.

Potential application of nanotechnology in the treatment, diagnosis, and prevention of schistosomiasis.

Schistosomiasis is one of the neglected tropical diseases that affect millions of people worldwide. Globally, it affects economically poor countries, typically due to a lack of proper sanitation systems, and poor hygiene conditions. Currently, no vaccine is available against schistosomiasis, and the preferred treatment is chemotherapy with the use of praziquantel. It is a common anti-schistosomal drug used against all known species of Schistosoma. To date, current treatment primarily the drug praziquantel has not been effective in treating Schistosoma species in their early stages. The drug of choice offers low bioavailability, water solubility, and fast metabolism. Globally drug resistance has been documented due to overuse of praziquantel, Parasite mutations, poor treatment compliance, co-infection with other strains of parasites, and overall parasitic load. The existing diagnostic methods have very little acceptability and are not readily applied for quick diagnosis. This review aims to summarize the use of nanotechnology in the treatment, diagnosis, and prevention. It also explored safe and effective substitute approaches against parasitosis. At this stage, various nanomaterials are being used in drug delivery systems, diagnostic kits, and vaccine production. Nanotechnology is one of the modern and innovative methods to treat and diagnose several human diseases, particularly those caused by parasite infections. Herein we highlight the current advancement and application of nanotechnological approaches regarding the treatment, diagnosis, and prevention of schistosomiasis.

Relationship of Clinical Picture, Phenotype of Oxidative Metabolism, Accentuation of Temperament Properties and Compliance in Patients with Gastroesophageal Reflux Disease

The purpose of the study is to establish the relationship between the accentuation of temperament properties, clinical picture of disease, and adherence to therapy in patients with gastroesophageal reflux disease with different phenotype of oxidative metabolism. Materials and methods. To achieve this goal, a case-control study was conducted in 156 patients aged 21 to 55 years (101 men and 55 women, mean age 38 years (IQR 29-46)) with verified gastroesophageal reflux disease with assessment of the clinical picture, assessment of the severity of symptoms using a visual analogue scale, concomitant pathology, adherence to therapy, phenotype of oxidative metabolism with the eufillin marker drug, determination of personal psychophysiological features using a temperament accentuation test. Statistical analyses were performed according to study objectives and data set features. Results. In patients with gastroesophageal reflux disease, 3 main personality types were identified: hyperthymic (n = 29; 19 %), mixed (n = 61; 39 %) and emotionally unstable type (n = 66; 42 %). By oxidative metabolism phenotype, 156 patients were divided into rapid (n = 51; 33 %), intermediate (n = 82; 52 %) and slow metabolizers (n = 23; 15 %). Analysis of multinomial logistic regression showed that in patients with rapid metabolism, in contrast to intermediate and slow metabolizers, low pain syndrome intensity should be expected (p = 0.014). There was no effect on the clinical presentation of temperament properties (p = 0.063). When studying the dependence of adherence to therapy on the properties of temperament and the patient`s metabolic level by multinomial logistic regression in patients with a hyperthymic type of accentuation of temperament properties, the probability of high adherence to therapy was more than 65 % in fast and intermediate metabolizers and 100 % in slow metabolizers (p = 0.006), in patients with mixed types the probability of high adherence to therapy is observed only in slow metabolizers (p = 0.006), patients with emotionally unstable type have a high probability of low adherence to therapy regardless of metabolic level (p = 0.006). Conclusion. To predict adherence of patients with gastroesophageal reflux disease to therapy, it is advisable to determine the level of oxidative metabolism and the type of accentuation of temperament properties.

Pharmacokinetics of antitubercular drugs in patients hospitalized with HIV-associated tuberculosis: a population modeling analysis.

Early mortality among hospitalized HIV-associated tuberculosis (TB/HIV) patients is high despite treatment. The pharmacokinetics of rifampicin, isoniazid, and pyrazinamide were investigated in hospitalized TB/HIV patients and a cohort of outpatients with TB (with or without HIV) to determine whether drug exposures differed between groups. Standard first-line TB treatment was given daily as per national guidelines, which consisted of oral 4-drug fixed-dose combination tablets containing 150 mg rifampicin, 75 mg isoniazid, 400 mg pyrazinamide, and 275 mg ethambutol. Plasma samples were drawn on the 3rd day of treatment over eight hours post-dose. Rifampicin, isoniazid, and pyrazinamide in plasma were quantified and NONMEM ® was used to analyze the data. Data from 60 hospitalized patients (11 of whom died within 12 weeks of starting treatment) and 48 outpatients were available. Median (range) weight and age were 56 (35 - 88) kg, and 37 (19 - 77) years, respectively. Bioavailability and clearance of the three drugs were similar between TB/HIV hospitalized and TB outpatients. However, rifampicin's absorption was slower in hospitalized patients than in outpatients; mean absorption time was 49.9% and 154% more in hospitalized survivors and hospitalized deaths, respectively, than in outpatients. Higher levels of conjugated bilirubin correlated with lower rifampicin clearance. Isoniazid's clearance estimates were 25.5 L/h for fast metabolizers and 9.76 L/h for slow metabolizers. Pyrazinamide's clearance was more variable among hospitalized patients. The variability in clearance among patients was 1.70 and 3.56 times more for hospitalized survivors and hospitalized deaths, respectively, than outpatients. Conclusion. We showed that the pharmacokinetics of first-line TB drugs are not substantially different between hospitalized TB/HIV patients and TB (with or without HIV) outpatients. Hospitalized patients do not seem to be underexposed compared to their outpatient counterparts,as well as hospitalized patients who survived vs who died within 12 weeks of hospitalization.

Evaluation of [18F]FMTEB in Sprague Dawley rats as a PET tracer for metabotropic glutamate receptor 5

Introduction[18F]FMTEB, along with other tracers, was developed as a promising PET radioligand for imaging metabotropic glutamate receptor subtype 5 (mGluR5). Despite favorable preliminary results, it has not been used further for studies of mGluR5. This paper presents an in-depth preclinical evaluation of [18F]FMTEB in healthy Sprague Dawley rats. Methods[18F]FMTEB was synthesized from a boronic ester precursor using copper-mediated fluorination.In vivo PET imaging was performed on six rats, of which three were pre-treated with a high affinity mGluR5 receptor antagonist. An additional 18 rats were used for ex vivo experiments for metabolite analyses in plasma, brain and urine, and for biodistribution and ex vivo brain autoradiography at different time points. Results[18F]FMTEB was synthesized in adequate radiochemical yield and a molar activity of 154 ± 64 GBq/μmol. Both in vivo imaging and ex vivo brain autoradiography showed high specificity for mGluR5, and the blocking experiments showed a clear decrease in radioactivity in mGluR5-rich brain areas. Metabolite analyses confirmed fast metabolism of the tracer in plasma. The percentage of parent compound in brain tissue exceeded 90 % up to 90 min after injection. Conclusion[18F]FMTEB produced via copper-mediated 18F-fluorination fulfilled the requirements for preclinical evaluation in rats. The absence of specific uptake in cerebellum and absence of defluorination of the tracer allowed cerebellum to be used as a reference tissue. Due to the fast kinetics in rats, the region-to-cerebellum ratios equilibrated within 30 min. These results prove [18F]FMTEB to be a good candidate for mapping mGluR5 in rat brain and a suitable alternative to [18F]FPEB.

Mechanisms of Susceptibility and Resilience to PTSD: Role of Dopamine Metabolism and BDNF Expression in the Hippocampus.

Susceptibility and resilience to post-traumatic stress disorder (PTSD) are recognized, but their mechanisms are not understood. Here, the hexobarbital sleep test (HST) was used to elucidate mechanisms of PTSD resilience or susceptibility. A HST was performed in rats 30 days prior to further experimentation. Based on the HST, the rats were divided into groups: (1) fast metabolizers (FM; sleep duration < 15 min); (2) slow metabolizers (SM; sleep duration ≥ 15 min). Then the SM and FM groups were subdivided into stressed (10 days predator scent, 15 days rest) and unstressed subgroups. Among stressed animals, only SMs developed experimental PTSD, and had higher plasma corticosterone (CORT) than stressed FMs. Thus, resilience or susceptibility to PTSD was consistent with changes in glucocorticoid metabolism. Stressed SMs had a pronounced decrease in hippocampal dopamine associated with increased expressions of catecholamine-O-methyl-transferase and DA transporter. In stressed SMs, a decrease in monoaminoxidase (MAO) A was associated with increased expressions of hippocampal MAO-A and MAO-B. BDNF gene expression was increased in stressed FMs and decreased in stressed SMs. These results demonstrate relationships between the microsomal oxidation phenotype, CORT concentration, and anxiety, and they help further the understanding of the role of the liver−brain axis during PTSD.

High-Throughput Metabolic Soft-Spot Identification in Liver Microsomes by LC/UV/MS: Application of a Single Variable Incubation Time Approach.

CYP-mediated fast metabolism may lead to poor bioavailability, fast drug clearance and significant drug interaction. Thus, metabolic stability screening in human liver microsomes (HLM) followed by metabolic soft-spot identification (MSSID) is routinely conducted in drug discovery. Liver microsomal incubations of testing compounds with fixed single or multiple incubation time(s) and quantitative and qualitative analysis of metabolites using high-resolution mass spectrometry are routinely employed in MSSID assays. The major objective of this study was to develop and validate a simple, effective, and high-throughput assay for determining metabolic soft-spots of testing compounds in liver microsomes using a single variable incubation time and LC/UV/MS. Model compounds (verapamil, dextromethorphan, buspirone, mirtazapine, saquinavir, midazolam, amodiaquine) were incubated at 3 or 5 µM with HLM for a single variable incubation time between 1 and 60 min based on predetermined metabolic stability data. As a result, disappearances of the parents were around 20-40%, and only one or a few primary metabolites were generated as major metabolite(s) without notable formation of secondary metabolites. The unique metabolite profiles generated from the optimal incubation conditions enabled LC/UV to perform direct quantitative estimation for identifying major metabolites. Consequently, structural characterization by LC/MS focused on one or a few major primary metabolite(s) rather than many metabolites including secondary metabolites. Furthermore, generic data-dependent acquisition methods were utilized to enable Q-TOF and Qtrap to continuously record full MS and MS/MS spectral data of major metabolites for post-acquisition data-mining and interpretation. Results from analyzing metabolic soft-spots of the seven model compounds demonstrated that the novel MSSID assay can substantially simplify metabolic soft-spot identification and is well suited for high-throughput analysis in lead optimization.

Emerging Trends in Curcumin Embedded Electrospun Nanofibers for Impaired Diabetic Wound Healing

Chronic wounds impose a significant burden on individuals and healthcare systems all over the world. Through clinical and preclinical investigations, inflammation and oxidative damage have been established as the primary causes of chronic wounds. These skin sores are easily exposed to microorganisms, which in turn cause inflammation and hinder the healing process. Additionally, microorganisms may cause an infection that prevents collagen production and reepithelialization. Curcumin’s antioxidant, anti-inflammatory, and anti-infectious characteristics, among others, have been identified as useful for diabetic wound healing management. However, curcumin has a few disadvantages, such as limited bioavailability, pH-dependent instability, water insolubility, slow cell absorption, and fast intracellular metabolism. These constraints necessitates the development of a suitable transporter to improve curcumin’s stability, bioavailability, therapeutic efficacy, and solubility. In recent years, Electrospun nanofiber mats have been an excellent choice for drug delivery because of their numerous advantages and inherent properties. Electrospun nanofibers have shown considerable promise as wound dressing materials. This review highlights the potential properties and recent advancements in using curcumin-loaded nanofibers for diabetic wound healing.

Long-term fasting: Multi-system adaptations in humans (GENESIS) study-A single-arm interventional trial.

[ClinicalTrials.gov], identifier [NCT05031598].

Personalization of Clotting Factor VIII Replacement Therapy Based on Population Pharmacokinetics in Adult Patients with Severe Hemophilia a Who Frequently Switch Factor VIII Concentrates

Interindividual pharmacokinetic differences in clotting factor VIII (FVIII) metabolism impede the dosing regimen optimization in patients with hemophilia A. The population pharmacokinetic (PK) analysis enables the estimation of FVIII pharmacokinetics in individual patients which is used to personalize dosing regimens. Therefore, we conducted a prospective study on adult patients with severe hemophilia A who received different FVIII concentrates for tertiary prophylaxis and whose dosage of FVIII was adjusted based on individual PK results. We aimed to compare the number of bleeding episodes and FVIII consumption before and after dosing adjustment. The study, conducted for 18 months for each participant, was divided into 3 phases: (1) pre-PK: assessments before FVIII dosing adjustment, (2) dosing adjustment based on the PK analysis of FVIII, and (3) assessments after FVIII dosing adjustment. All patients gave informed consent before enrolment, and all procedures were carried out according to the Declaration of Helsinki. During the study patients frequently changed FVIII concentrates (each patient used 3-5 different products) which reflects the standard of care in adult patients with hemophilia in Poland. During phase 1 of the study, over 5-13 months [median: 11.0 months, mean(standard deviation - SD): 10.8(1.9) months], patients recorded FVIII consumption and bleedings using electronic diaries (myPKFiT® licensed for octocog alfa). In phase 2 of the study, a PK analysis (clearance, half-time, time to reach the 1 IU/dl concentration) was performed: following the 72-hour washout period, blood samples were collected, and patients received the infusion of octocog alfa with the mean dose (SD) of 51.1(1.7) IU/kg. Two more blood samples were collected 3-4 h and 24-36 h after the infusion. Plasma FVIII activity was measured with a one-stage clotting assay, and the FVIII inhibitor with the Nijmegen modification of the standard Bethesda method. The myPKFiT® was used to obtain individualized FVIII dosing regimens based on PK analysis results. The dosing adjustment was offered to patients who experienced breakthrough bleeds during phase 1 or in whom the pre-PK treatment did not secure FVIII trough level of >1 IU/dl. In case of favorable PK results and no breakthrough bleeds during phase 1, a less intensive regimen was implemented. In phase 3 of the study (which lasted for 5-13 months, median: 7.7 months, mean(SD): 7.6(1.6) months), patients continued treatment with locally available FVIII concentrates and used electronic diaries to record FVIII consumption and bleedings. All bleeding rates were annualized (annualized bleeding rates - ABR). The final analysis set included 22 male patients, aged 23-68 years. The clearance of octocog alpha ranged from 0.014 to 0.051 dL/h/kg [mean(SD), 0.030±0.010 dL/h/kg; coefficient of variation (CV)=33%], half-life - from 9.1 to 27.9 h (14.6(4.3) h, CV=29%), and time to reach 1 IU/dl - from 51 to 179 h [91(29) h, CV=32%]. Three individuals were categorized as slow metabolizers (clearance of 0.014, 0.018, and 0.019 dL/h/kg), and 2 as fast metabolizers (clearance of 0.048 and 0.051 dL/kg/h). FVIII inhibitor was undetectable (<0.5 BU/ml) in all patients. After the PK analysis, 21 of 22 patients met the criteria of FVIII dosing adjustment. Four patients did not agree to change the regimen. Seventeen patients modified it according to the PK results (10 of them had FVIII trough levels of >1 IU/dl and 7 of them of <1 IU/dl in phase 1 of the study). Changing the dosing regimen in the 17 patients resulted in ABR reduction compared to the pre-PK phase: a decrease of 3.1-fold in total ABR (p=0.045 for dependent samples t-test); 3.2-fold in spontaneous ABR (p=0.046); and 3.1-fold in injury-related ABR (p=0.072). The consumption of FVIII due to bleeds had decreased by 77% (p=0.034). In conclusion, personalizing the FVIII replacement therapy based on population PK models helps to lower bleeding risk and drug consumption in patients with severe hemophilia A. Presented results suggest that prophylaxis regimen based on PK analysis carried out with octocog alfa and myPKFiT® application is clinically effective also with the use of other FVIII concentrates.

Possibilities of clinical application of articaine

Articaine is an intermediate-potency and short-acting amide local anesthetic with a fast metabolism due to an ester group in its structure. Articaine was widely used in dental practice, but now has an effective form for surgical and anesthetic use. Articaine is effective with local infiltration or peripheral nerve block in dentistry, when administered as a spinal, epidural, ocular, or regional nerve block, or when intravenously injected for regional anesthesia. Comparative trials have not revealed a generally significant difference in its clinical effects from those of other short-acting local anesthetics, such as lidocaine, prilocaine, and chloroprocaine, and no conclusive evidence has demonstrated above-average neurotoxicity. Thus, this review discusses the pharmacokinetics and pharmacodynamics, clinical efficacy, and possible side effects of articaine.

Chitosan/Cyclodextrin Nanospheres for Potential Nose-to-Brain Targeting of Idebenone.

Idebenone (IDE) is a powerful antioxidant that is potentially active towards cerebral diseases, but its low water solubility and fast first pass metabolism reduce its accumulation in the brain, making it ineffective. In this work, we developed cyclodextrin-based chitosan nanospheres (CS NPs) as potential carriers for nose-to-brain targeting of IDE. Sulfobutylether-β-cyclodextrin (SBE-β-CD) was used as a polyanion for chitosan (CS) and as a complexing agent for IDE, permitting its encapsulation into nanospheres (NPs) produced in an aqueous solution. Overloading NPs were obtained by adding the soluble IDE/hydroxypropyl-β-CD (IDE/HP-β-CD) inclusion complex into the CS or SBE-β-CD solutions. We obtained homogeneous CS NPs with a hydrodynamic radius of about 140 nm, positive zeta potential (about +28 mV), and good encapsulation efficiency and drug loading, particularly for overloaded NPs. A biphasic release of IDE, finished within 48 h, was observed from overloaded NPs, whilst non-overloaded CS NPs produced a prolonged release, without a burst effect. In vitro biological studies showed the ability of CS NPs to preserve the antioxidant activity of IDE on U373 culture cells. Furthermore, Fourier transform infrared spectroscopy (FT-IR) demonstrated the ability of CS NPs to interact with the excised bovine nasal mucosa, improving the permeation of the drug and potentially favoring its accumulation in the brain.