Plasma Concentrations Of Metabolites Research Articles

Abstract PS15-07: Proxalutamide plus Endocrine Therapies in Women with HR+/HER2-/AR+ Metastatic Breast Cancer: A Phase Ic Study

Abstract Abstract Background: Resistance to endocrine therapy (ET) and cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) is a major obstacle to the management of hormone-receptor (HR)+/human epidermal growth factor receptor 2 (HER2)- metastatic breast cancer (mBC). Targeting the AR signaling pathway has been demonstrated with promising results in this population. This phase Ic study aimed to assess the safety, efficacy, pharmacokinetic (PK), and pharmacodynamic (PD) characteristics of the combination of proxalutamide, a high-affinity AR antagonist, with ETs in androgen receptor (AR)+/HR+/HER2- mBC. Methods: Patients in part 1 regimen-finding phase received proxalutamide plus specific ETs (letrozole [cohort A], exemestane [cohort B], or fulvestrant [cohort C]) and were assessed for dose-limiting toxicity (DLT), PK, PD, and anti-tumor activity. Part 2 expansion phase evaluated the safety and efficacy of proxalutamide plus fulvestrant. The primary endpoint was safety and tolerability. Results: Between June 18, 2019, and Sep 15, 2022, 38 (18 in part 1 and 20 in part 2) patients were treated. Efficacy analysis indicated that the ORR was 16.7% (2/12, 95% CI, 2.1%-48.4%) for cohort C and 15.0% (3/20; 95% CI, 3.2%-37.9%) for part 2. Patients achieved a median progression-free survival (PFS) of 6.4 months (95% CI, 2.7-19.3) in cohort C while an mPFS of 11.0 months (95% CI, 5.5- not estimable) in part 2. In part 1, no DLTs were reported. Grade 3 or more treatment-emergent adverse events (TEAEs) were observed in 11 (29.7%) patients (7 [18.9%] in part 1 and 4 [10.8%] in part 2) and mainly included neutrophil count decreased (8.1%) and platelet count decreased (5.4%). Seven (18.9%) had serious AEs (4 [10.8%] in part 1 and 3 [8.1%] in part 2)[1]. PD results showed a greater reduction of estradiol in cohort C compared with that in cohort B. In addition, proxalutamide was absorbed rapidly into the body with the plasma concentrations of proxalutamide and metabolites reaching a nearly steady state on day 29. Patients with AR/ER of ≤1 seemed to achieve longer PFS over those of >1 (8.4 months vs. 4.1 months). Conclusions: These findings suggested favorable clinical outcomes and safety profiles of the combination of proxalutamide and fulvestrant in AR+/HR+/HER2- mBC patients who have progressed on the first-line therapy, and maybe with better efficacy in patients with lower AR/ER ratio. Trial registration: NCT20191063 Citation Format: Hui-Ping Li, Guohong Song, Hanfang Jiang, Xu Liang, Xiaojia Wang, Hua Yang, Lili Zhang, Youzhi Tong. Proxalutamide plus Endocrine Therapies in Women with HR+/HER2-/AR+ Metastatic Breast Cancer: A Phase Ic Study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS15-07.

Abstract 7660: L-Arginine metabolism is of prognostic relevance in women with breast cancer, but varies considerably between subtypes in vitro - A bedside-to-bench translational approach

Abstract Availability of the semi-essential amino acid L-arginine (L-arg) is limiting for proliferation in highly proliferative tissues. L-Arg is also a substrate for nitric oxide synthases (NOS) and arginases (ARG) 1 and 2. Methylation of L-arg residues within proteins by protein L-arg methyltransferases (PRMTs) leads to asymmetric (ADMA) and symmetric dimethylarginine (SDMA). Protein L-arg methylation is an important post-translational mechanism to regulate gene expression and cell cycle control. We measured L-arg and its metabolites in a prospective cohort of patients with primary breast cancer (BC). We further measured these metabolites and expression of genes involved in L-arg metabolic pathways in cell lines representing intrinsic BC subtypes. Plasma L-arg-related metabolite concentrations from 243 women with primary BC were associated with total mortality and disease recurrence during a median follow-up of 88 (IQR, 82-93) months. MCF-7, BT-474, SK-BR-3, and MDA-MB-468 cells representing ER-positive, HER2-positive, and triple negative BC were cultured in standard conditions and compared to MCF-12A normal breast epithelial cells. The plasma (in vivo) and intracellular concentrations (in vitro) of L-arg, L-ornithine (L-orn), L-citrulline (L-cit), ADMA, and SDMA were measured by UPLC-MS/MS. mRNA expression was quantified by qRT-PCR and protein expression was analyzed by Western Blot. In vivo, the plasma concentrations of all L-arg metabolites differed significantly between BC patients and healthy controls. L-Arg and ADMA were significantly higher in patients with recurrent disease and in those who died during follow up. ADMA was significantly associated with total mortality and recurrent disease in Luminal A patients; low L-orn/L-arg ratio was associated with survival in HER2+ BC patients, and low L-cit was associated with survival in triple negative BC. With the exception of MCF-7 cells, DDAH1 and DDAH2 mRNA concentrations in vitro were significantly higher in BC cells than in MCF-12A cells (DDAH1: 32-44 fold, DDAH2: 1.7-4.2 fold; p<0.05). These differences were mirrored by DDAH1 and DDAH2 protein concentrations. By contrast, MCF-7 cells were characterized by low DDAH1 and DDAH2, but high PRMT4 and PRMT6 mRNA expression and high L-arg content. BT-474 cells showed high ARG2 expression and high L-arg and L-orn concentrations, and MDA-MB-468 cells had the highest L-cit/L-arg ratio. In conclusion, regulation of L-arg metabolic pathways shows a complex and differential pattern between intrinsic BC subtypes, which is mirrored in representative cell lines in vitro. ADMA is a prognostic biomarker in Luminal A breast cancer patients; its metabolizing enzyme, DDAH, is highly overexpressed in BC cells in vitro. Thus, fingerprinting of L-arg metabolism may offer novel personalized treatment options within intrinsic BC subtypes. Citation Format: Juliane Hannemann, Leticia Oliveira Ferrer, Antonia Röglin, Fiona Kleinsang, Volkmar Müller, Isabell Witzel, Rainer Böger. L-Arginine metabolism is of prognostic relevance in women with breast cancer, but varies considerably between subtypes in vitro - A bedside-to-bench translational approach [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7660.

CMS121: a novel approach to mitigate aging-related obesity and metabolic dysfunction.

Modulated by differences in genetic and environmental factors, laboratory mice often show progressive weight gain, eventually leading to obesity and metabolic dyshomeostasis. Since the geroneuroprotector CMS121 has a positive effect on energy metabolism in a mouse model of type 2 diabetes, we investigated the potential of CMS121 to counteract the metabolic changes observed during the ageing process of wild type mice. Control or CMS121-containing diets were supplied ad libitum for 6 months, and mice were sacrificed at the age of 7 months. Blood, adipose tissue, and liver were analyzed for glucose, lipids, and protein markers of energy metabolism. The CMS121 diet induced a 40% decrease in body weight gain and improved both glucose and lipid indexes. Lower levels of hepatic caspase 1, caspase 3, and NOX4 were observed with CMS121 indicating a lower liver inflammatory status. Adipose tissue from CMS121-treated mice showed increased levels of the transcription factors Nrf1 and TFAM, as well as markers of mitochondrial electron transport complexes, levels of GLUT4 and a higher resting metabolic rate. Metabolomic analysis revealed elevated plasma concentrations of short chain acylcarnitines and butyrate metabolites in mice treated with CMS121. The diminished de novo lipogenesis, which is associated with increased acetyl-CoA, acylcarnitine, and butyrate metabolite levels, could contribute to safeguarding not only the peripheral system but also the aging brain. By mimicking the effects of ketogenic diets, CMS121 holds promise for metabolic diseases such as obesity and diabetes, since these diets are hard to follow over the long term.

Abstract P397: Choline Metabolites Are Associated With Non-Alcoholic Fatty Liver Disease: A Coronary Artery Risk Development in Young Adults (CARDIA) Study

Background: Non-alcoholic fatty liver disease (NAFLD), a common cause of chronic liver disease, has become increasingly prevalent. Choline deficiency has long been a model for the study of accelerated NAFLD, in preclinical and small-scale human studies. More recently, NAFLD has been associated with choline metabolites betaine (inversely) and trimethylamine N-oxide (TMAO) (positively). There has been a paucity of research on circulating choline metabolites and NAFLD in diverse and population-based cohort studies. Methods: We used data from 2,413 CARDIA participants who did not self-report liver disease or heavy alcohol intake at Y15, had stored plasma available from Y15, and chest computed tomography (CT) measures from Y25. NAFLD was defined as a mean CT-derived liver attenuation score <51 Hounsfield units; severe NAFLD was <40 Hounsfield units. Liquid chromatography mass spectrometry was used to quantify choline, betaine, and TMAO concentrations from stored plasma samples. Plasma metabolite concentrations were standardized for analysis. Plasma TMAO was natural log transformed for normality. Multivariable-adjusted logistic regression models quantified associations between plasma choline metabolites and NAFLD. Results (Table): In fully adjusted models, plasma betaine was inversely associated with NAFLD, and plasma TMAO was positively associated with NAFLD. Plasma choline was not associated with NAFLD in fully adjusted models. Conclusions: Our findings support an inverse association between plasma betaine and NAFLD in a diverse, population-based US cohort, and a positive association between plasma TMAO and NAFLD. Circulating betaine reflects dietary intake of betaine, as well as conversion from choline. TMAO reflects an alternative fate of choline, through metabolism by the gut microbiota. These results contribute to a growing literature on choline metabolism and cardiometabolic risk.

The acute toxic effect of Chinese medicine Fuzi is exacerbated in kidney yang deficiency mice due to metabolic difference

Ethnopharmacological relevanceThe proper application of toxic medicines is one of the characteristics of traditional Chinese medicines, and the use of traditional Chinese medicines follows the principle of dialectical treatment. It is necessary to combine different “syndrome” or “disease” states with the toxicity of traditional Chinese medicines to form a reliable toxicity evaluation system. Fuzi, the lateral root of Aconitum carmichaelii Debx, is recognized as a panacea for kidney yang deficiency syndrome, however, its toxic effects significantly limit its clinical application. Aim of the studyHerein, our research aimed to explore the toxic effects of Fuzi on syndrome models, and tried to reveal the underlying mechanisms. Materials and methodsFirstly, the mouse model of kidney yang deficiency syndrome was established through intramuscular injection of 25 mg/kg hydrocortisone per day for 10 consecutive days. Then, the acute toxicity of Fuzi in normal mice and kidney yang deficiency model mice was explored. Finally, the plasma metabolite concentrations and liver CYP3A4 enzyme activity were analyzed to reveal the possible mechanisms of the different pharmacological and toxicological effects of Fuzi in individuals with different physical constitutions. ResultsIt was found that the treatment with Fuzi (138 g/kg) had serious toxic effects on kidney yang deficiency mice, leading to the death of 80% of the mice, whereas it showed no lethal toxicity in normal mice. This indicates that Fuzi induced greater toxicity in kidney yang deficiency mice than in normal ones. The liver CYP3A4 enzyme activity in kidney yang deficiency mice was decreased by 20% compared to the controls, resulting in slower metabolism of the toxic diester diterpenoid alkaloids in Fuzi. ConclusionIn conclusion, our study showed that changes of the metabolic enzyme activity in individuals with different syndromes led to different toxic effects of Chinese medicines, emphasizing the crucial importance of considering individual physical syndromes in the clinical application of traditional Chinese medicine, and the significance of conducting safety evaluations and dose predictions on animal models with specific syndromes for traditional Chinese medicines.

Association between dietary macronutrient composition and plasma one-carbon metabolites and B-vitamin cofactors in patients with stable angina pectoris.

Elevated plasma concentrations of several one-carbon metabolites are associated with increased CVD risk. Both diet-induced regulation and dietary content of one-carbon metabolites can influence circulating concentrations of these markers. We cross-sectionally analysed 1928 patients with suspected stable angina pectoris (geometric mean age 61), representing elevated CVD risk, to assess associations between dietary macronutrient composition (FFQ) and plasma one-carbon metabolites and related B-vitamin status markers (GC-MS/MS, LC-MS/MS or microbiological assay). Diet-metabolite associations were modelled on the continuous scale, adjusted for age, sex, BMI, smoking, alcohol and total energy intake. Average (geometric mean (95 % prediction interval)) intake was forty-nine (38, 63) energy percent (E%) from carbohydrate, thirty-one (22, 45) E% from fat and seventeen (12, 22) E% from protein. The strongest associations were seen for higher protein intake, i.e. with higher plasma pyridoxal 5'-phosphate (PLP) (% change (95 % CI) 3·1 (2·1, 4·1)), cobalamin (2·9 (2·1, 3·7)), riboflavin (2·4 (1·1, 3·7)) and folate (2·1 (1·2, 3·1)) and lower total homocysteine (tHcy) (-1·4 (-1·9, -0·9)) and methylmalonic acid (MMA) (-1·4 (-2·0, -0·8)). Substitution analyses replacing MUFA or PUFA with SFA demonstrated higher plasma concentrations of riboflavin (5·0 (0·9, 9·3) and 3·3 (1·1, 5·6)), tHcy (2·3 (0·7, 3·8) and 1·3 (0·5, 2·2)) and MMA (2·0 (0·2, 3·9) and 1·7 (0·7, 2·7)) and lower PLP (-2·5 (-5·3, 0·3) and -2·7 (-4·2, -1·2)). In conclusion, a higher protein intake and replacing saturated with MUFA and PUFA were associated with a more favourable metabolic phenotype regarding metabolites associated with CVD risk.

The effects of food on the pharmacokinetics of mycophenolate mofetil in healthy horses.

Additional immunomodulatory treatment is needed for the management of immune-mediated disease in horses. Mycophenolate mofetil (MMF) is an immunomodulatory agent used in human and veterinary medicine for the prevention of graft rejection and the management of autoimmune diseases. Few studies exist investigating the pharmacokinetics of MMF in horses. The aim of this study was to evaluate the pharmacokinetics of a single dose of MMF in healthy horses in the fed vs. fasted state. Six healthy Standardbred mares were administered MMF 10 mg/kg by a nasogastric (NG) tube in a fed and fasted state. A six-day washout period was performed between the two doses. No statistically significant differences in mycophenolic acid (MPA) concentrations were seen at any time point apart from 8 h, when plasma metabolite concentrations were significantly higher in the fasted state compared to the fed state (p = .038). Evidence of enterohepatic recirculation was seen only in the fasted state; this did not yield clinical differences in horses administered a single-dose administration but may be significant in horses receiving long-term MMF treatment.

Tryptophan metabolites and gut microbiota play an important role in pediatric migraine diagnosis

BackgroundThe pathogenesis of pediatric migraine remains unclear and presents challenges in diagnosis. Recently, growing evidence has indicated that the gut microbiota can exert modulatory functions at the gut-brain axis by directly or indirectly regulating tryptophan metabolism. Consequently, we aimed to elucidate the potential association among gut microbiota, tryptophan metabolism, and pediatric migraine while also identifying diagnostic biomarkers for pediatric migraine.MethodsThe gut microbiota composition of 33 migraine children and 42 healthy children, aged less than ten years, from the GMrepo database, was analyzed using the Shannon index, Simpson index, principal coordinates analysis, and Wilcoxon rank-sum test. Microbial diagnostic biomarkers were identified using linear discriminant analysis effect size, ridge regression, and random forest. Plasma concentrations of tryptophan metabolites investigated by enzyme-linked immunosorbent assay were compared between 51 migraine children and 120 healthy children, aged less than eighteen years, using t tests and analysis of variance. The receiver operating characteristic curve was performed to evaluate the diagnostic value of microbial and metabolite biomarkers in pediatric migraine.ResultsDifferences in the composition of gut microbiota, notably the genera that regulate tryptophan metabolism, were observed in pediatric migraine children. Further investigations revealed a significant decrease in plasma kynurenic acid levels (p < 0.001) among migraine children, along with a significant increase in serotonin (p < 0.05) and quinolinic acid (p < 0.001). Subsequently, we established the normal reference intervals for plasma concentrations of tryptophan metabolites in children. More importantly, the ratio of kynurenic acid to quinolinic acid (AUC: 0.871, sensitivity: 86.3%, specificity: 83.3%) exhibited excellent diagnostic efficacy for pediatric migraine.ConclusionOur study suggests that the gut microbiota may play an important role in the development of pediatric migraine by regulating tryptophan metabolism. We believe that microbial and metabolite biomarkers are sensitive diagnostic tests for pediatric migraine.Trial registrationThe study was registered at ClinicalTrials.gov (NCT05969990).

Transient Decrease in Sperm Motility after Plateletpheresis

AbstractAlthough people are constantly exposed to phthalates little is known about the extent to which PAEs affect sperm. Most studies do not address changes at the single-cell level. Our study concentrated on the examination of donors who were assumed to have been exposed to high levels of phthalate under plateletpheresis. We used Computer-Assisted-Sperm-Analysis to study the association between the most potent phthalate, di-2-ethylhexyl phthalate, and a decrease in sperm motility. In an exploratory in vivo study, we investigated whether plateletpheresis of donors led to an increase in the concentration of active metabolites of DEHP in seminal plasma and whether this had an effect on sperm motility. PAE metabolites and sperm motility parameters of ejaculate donors were analyzed at a single-cell level before and after plateletpheresis. We found an increase in PAE metabolite concentration in the seminal plasma, associated with a decrease in flagellar beat frequency after plateletpheresis. Follow-up analysis showed that this was a transient effect of plateletpheresis in terms of a PAE concentration increase in seminal plasma and a decrease in sperm motility. This study shows that plateletpheresis results in high levels of phthalate exposure and that these are associated with a transient and reversible decrease in sperm motility.

Effect of feeding calf starter with calcium salts of medium-chain fatty acids on the growth and metabolic hormones in calves.

We investigated the effects of a calf starter supplemented with calcium salts of medium-chain fatty acids (MCFA-Ca) on growth and plasma hormone concentration in calves. Twelve Holstein calves were randomly assigned to two dietary groups (without supplementation [CON] and supplemented with MCFA-Ca [MCFA]) from 4 d of age. Calves were fed 1.0kg/d of milk replacer until 5wk of age and were completely weaned at 7wk of age. Calves in the MCFA group received a calf starter containing 1% MCFA-Ca. dry matter intake (DMI) was measured daily, and body weight was measured weekly. Rumen fluid was collected at 13wk of age to measure pH and volatile fatty acid concentration. Preprandial blood samples were collected weekly to measure the basal plasma hormone and metabolite concentrations. At 4, 8, and 13wk of age, peri-prandial blood samples were collected every 30min, from 60min before feeding to 120min after feeding, to observe metabolic responses to feeding. In addition, insulin sensitivity was assessed using euglycemic-hyperinsulinemic clamps at 4, 8, and 13wk of age in three calves from each treatment. There were no differences in starter and hay DMI between the treatments. However, the average daily gain (ADG) after weaning was higher in the MCFA group than in the CON group. Weekly changes in plasma parameters did not differ between the treatments. Plasma concentrations of preprandial ghrelin and postprandial total ketone bodies at 13wk of age were higher in the MCFA group than in the CON group. At 8wk of age, peri-prandial plasma insulin concentrations were lower in the MCFA group than in the CON group. There were no differences between the treatments in terms of insulin sensitivity. The present study suggested that feeding weaning calves MCFA-Ca increases the ADG during the postweaning period, which may be mediated by endocrine signals, such as enhanced ghrelin secretion and decreased insulin secretion, without altering insulin sensitivity.

Changes in plasma metabolite concentrations and enzyme activities in aging riding horses.

In older horses, basal metabolic rate decreases, and plasma metabolite and hormone concentrations related to energy metabolism change. The occurrence of age-related diseases, which increases in old animals, may enhance inflammatory reactivity (inflammaging). Finding the appropriate treatment for inflammaging at an early stage may prevent various age-related diseases. Changes in metabolite and hormone concentrations and enzyme activities involved in energy metabolism in the plasma of clinically healthy riding horses of various ages were measured to identify biomarkers of inflammaging (persistent low-grade inflammation that occurs with aging). All horses were clinically healthy, and their body condition scores (BCSs) were 4 or 5 (9-point scale). Plasma triglyceride (TG), total cholesterol (T-Cho), blood urea nitrogen (BUN), insulin concentrations, malondialdehyde (MDA), and serum amyloid A (SAA) concentrations generally increased with age. Adiponectin concentrations, plasma superoxide dismutase (SOD), and leukocyte AMP-activated protein kinase (AMPK) activities decreased, while plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT), and glutathione peroxidase (GPx) remained unchanged as horses aged. Although riding horses that partake in continuous exercise seems to be less likely to develop inflammaging, horses over 17 years of age tend to show proinflammatory signs with disordered lipid metabolism. In riding horses, SAA, in combination with other markers, may be a useful biomarker for inflammaging and dysregulated lipid metabolism in aging horses.

Sex differences in plasma metabolites in a guinea pig model of allergic asthma.

Sex seems to be a contributing factor in the pathogenesis of bronchial asthma. This study aimed to find sex-related differences in metabolome measured by hydrogen-1 nuclear magnetic resonance ((1)H NMR) spectroscopy in healthy and ovalbumin (OVA)-sensitized guinea pigs. Adult male and female animals were divided into controls and OVA-sensitized groups. OVA-sensitization was performed by OVA systemic and inhalational administration within 14 days; on day 15, animals were killed by anesthetic overdose followed by exsanguination. Blood was taken and differential white blood cell count was measured. Left lung was saline-lavaged and differential cell count in the bronchoalveolar lavage fluid (BALF) was measured. After blood centrifugation, plasma was processed for (1)H NMR analysis. Metabolomic data was evaluated by principal component analysis (PCA). Eosinophil counts elevated in the BALF confirming eosinophil-mediated inflammation in OVA-sensitized animals of both sexes. Sex differences for lactate, glucose, and citrate were found in controls, where these parameters were lower in males than in females. In OVA-sensitized males higher glucose and lower pyruvate were found compared to controls. OVA-sensitized females showed lower lactate, glucose, alanine, 3-hydroxy-butyrate, creatine, pyruvate, and succinate concentrations compared to controls. In OVA-sensitized animals, lactate concentration was lower in males. Data from females (healthy and OVA-sensitized) were generally more heterogeneous. Significant sex differences in plasma concentrations of metabolites were found in both healthy and OVA-sensitized animals suggesting that sex may influence the metabolism and may thereby contribute to different clinical picture of asthma in males and females.

Effect of CYP2C19 Pharmacogenetic Testing on Predicting Citalopram and Escitalopram Tolerability and Efficacy: A Retrospective, Longitudinal Cohort Study.

Background-Various antidepressant agents are metabolized by the CYP2C19 enzyme, including Citalopram and Escitalopram. Variation in CYP2C19 expression might give rise to different plasma concentrations of the active metabolites, potentially affecting both drugs' efficacy and tolerability. Aim-The aim of this study was to evaluate differences in the Escitalopram and Citalopram efficacy and tolerability between different CYP2C19 genotype-based metabolizing categories in outpatients suffering from major depressive disorder (MDD). Methods-In a retrospective, longitudinal cohort study of electronic medical-record data, 283 patients with MDD who were prescribed Escitalopram or Citalopram with the available CYP2C19-genotyping test were enrolled. The primary efficacy end point was adverse drug reactions recorded in the medical files. A proportional-odds, multilevel-regression model for longitudinal ordinal data was used to estimate the relation between the CYP2C19 genotype and adverse drug reactions, adjusting for potential confounding variables and other explanatory variables. Latent-class analysis (LCA) was utilized to detect the presence of clinically significant subgroups and their relation to an individual's metabolizing status for CYP2D6/CYP2C19. Results-With poor CYP2C19 metabolizers as a reference, for each unit difference in the activity score of the CYP2C19 phenotype, the odds ratio for drug intolerability was lowered by 0.73 (95% credible intervals: 0.56-0.89), adjusting for significant covariates. In addition, applying LCA, we identified two qualitatively different subgroups: the first group (61.85%) exhibited multiple side effects, low compliance, and frequent treatment changes, whereas the second group (38.15%) demonstrated fewer side effects, good adherence, and fewer treatment changes. The CYP2C19 phenotype was substantially associated with the group membership. Conclusions-We found a positive association between the CYP2C19 activity scores, as inferred from the genotype, and both the efficacy of and tolerability to both Es/Citalopram. LCA enabled valuable insights into the underlying structure of the population; the CYP2C19 phenotype has a predictive value that discriminates between low-adherence, low-drug-tolerance, and low-response patients and high-adherence, high-drug-tolerance, and high-response patients. Personalized medicine based on CYP2C19 genotyping could evolve as a promising new avenue towards mitigating Escitalopram and Citalopram therapy and the associated side effects and enhancing treatment success.

Pharmacokinetics of oral spironolactone in infants up to 2years of age.

Spironolactone is a potassium sparing diuretic used for decades. Until now, pharmacokinetic (PK) studies of spironolactone have not been conducted in infants and therefore pediatric dosing is based on expert opinion. We aimed to describe the PK profiles of spironolactone and its main metabolites (7alpha-thiomethylspironolactone (TMS) and canrenone (CAN)) in infants up to two years of age. The PK of spironolactone and its main metabolites were evaluated following an oral administration of spironolactone (1mg/kg/dose) to pediatric patients with chronic heart failure, ascites, and/or oedema. The plasma concentration of spironolactone and metabolites (TMS and CAN) was determined using an ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Based on rich sampling PK data, the estimation of population PK parameters was performed using nonlinear mixed-effects modelling software Monolix 2018R2. A total of 150 spironolactone, 158 TMS, and 158 CAN concentrations from 23 patients (ages: 3days-21months; median weight 4.3kg (2.2-12.6)) were available for PK analysis. A one-compartment model for spironolactone, TMS, and CAN best fitted the data. The median (range) of individual estimated apparent clearance values were 47.7 (11.9-138.1) L/h for spironolactone, 9.7 (1.5-66.9) L/h for TMS, and 1.0 (0.2-5.9) L/h for CAN. The disposition of spironolactone and metabolites was mainly affected by size of the patient: body weight explained 22% of inter-individual variability of spironolactone clearance. None of the undesirable effects of spironolactone was documented during the study period. The pharmacokinetics of spironolactone and its metabolites was highly variable between patients below 2years of age. Body weight explained a significant part of this variability; this highlights the need to take it into account for dosing prescription in this population. (Clinical trial Registration Number 2013-001189-40).

2541. Steady-state PK of Fixed Dose Dolutegravir+Rilpivirine in Hemodialysis

Abstract Background Fixed dose combination (FDC) dolutegravir (DTG) plus rilpivirine (RPV) is an approved antiretroviral treatment regimen for people with HIV. The steady-state PK of FDC DTG+RPV in those requiring hemodialysis (HD) has not been previously studied. Methods We performed a single-center, prospective evaluation of the steady-state PK of FDC DTG (50mg)+RPV(25mg) in HIV-negative adults either requiring HD (n=4; 2 men, 2 women) or with normal renal function, defined as CrCl ≥ 75mL/min (n=2; 1 man, 1 woman). All participants received DTG+RPV daily for 10-14 days with food before undergoing an intensive 24-hour PK evaluation (performed between dialysis days for those requiring HD). Plasma drug and metabolite concentrations were measured using a validated LC/MS/MS assay method (QTRAP 6500+LC-MS/MS system) with turboelectrospray source operating in both positive (confirmation) and negative (quantification) modes. We did not evaluate dialysis extraction of DTG+RPV. Descriptive PK parameters were calculated. Results No participant experienced serious or grade 3-4 adverse events; there were no study discontinuations. The 4 HD and 2 normal renal function participants were of similar ages (range, 50-60 vs 53-58 years) and BMI (range, 18.5-28.2 vs 20.3-24.0 kg/m2). The Table shows the PK parameters assessed in the study population for circulating plasma DTG, DTG-glucuronide (DTG’s primary metabolite), and RPV. Conclusion In this study, HD did not lead to clinically appreciable differential exposures to DTG and RPV; the markedly increased exposure to DTG-glucoranide (which is considered inert) in HD suggests increased UGT1A1 activation. All participants maintained exposures throughout the dosing interval greater than the reported IC90 efficacy values for DTG (64ng/mL) and RPV (12ng/mL). These data suggest no dosing modifications are needed for the FDC DTG+RPV regimen in HD. Disclosures Samir K. Gupta, MD, Gilead Sciences: Advisor/Consultant|ViiV Healthcare: Advisor/Consultant|ViiV Healthcare: Grant/Research Support Allon Friedman, MD, Eli Lilly: Advisor/Consultant|Eli Lilly: Stocks/Bonds|GI Dynamics: Advisor/Consultant|Gila Therapeutics: Advisor/Consultant

Interplay between diet, circulating indolepropionate concentrations and cardiometabolic health in US populations

ObjectivesTo identify indolepropionate (IPA)-predicting gut microbiota species, investigate potential diet–microbiota interactions, and examine the prospective associations of circulating IPA concentrations with type 2 diabetes (T2D) and coronary heart disease (CHD)...

Chronic kidney disease may evoke anxiety by altering CRH expression in the amygdala and tryptophan metabolism in rats

Chronic kidney disease (CKD) is associated with anxiety; however, its exact mechanism is not well understood. Therefore, the aim of the present study was to assess the effect of moderate CKD on anxiety in rats. 5/6 nephrectomy was performed in male Wistar rats. 7 weeks after, anxiety-like behavior was assessed by elevated plus maze (EPM), open field (OF), and marble burying (MB) tests. At weeks 8 and 9, urinalysis was performed, and blood and amygdala samples were collected, respectively. In the amygdala, the gene expression of Avp and the gene and protein expression of Crh, Crhr1, and Crhr2 were analyzed. Furthermore, the plasma concentration of corticosterone, uremic toxins, and tryptophan metabolites was measured by UHPLC-MS/MS. Laboratory tests confirmed the development of CKD. In the CKD group, the closed arm time increased; the central time and the total number of entries decreased in the EPM. There was a reduction in rearing, central distance and time in the OF, and fewer interactions with marbles were detected during MB. CKD evoked an upregulation of gene expression of Crh, Crhr1, and Crhr2, but not Avp, in the amygdala. However, there was no alteration in protein expression. In the CKD group, plasma concentrations of p-cresyl-sulfate, indoxyl-sulfate, kynurenine, kynurenic acid, 3-hydroxykynurenine, anthranilic acid, xanthurenic acid, 5-hydroxyindoleacetic acid, picolinic acid, and quinolinic acid increased. However, the levels of tryptophan, tryptamine, 5-hydroxytryptophan, serotonin, and tyrosine decreased. In conclusion, moderate CKD evoked anxiety-like behavior that might be mediated by the accumulation of uremic toxins and metabolites of the kynurenine pathway, but the contribution of the amygdalar CRH system to the development of anxiety seems to be negligible at this stage.

Evaluation of the effect of CYP2D6*3, *4,*10, and *17 polymorphisms on the pharmacokinetic of tamoxifen and its metabolites in patients with hormone-positive breast cancer

Background and objectiveA high rate of interindividual variability in response to tamoxifen (TAM) in breast cancer patients with CYP2D6 polymorphism has been reported, which affects the patient’s therapeutic outcome. The objective of this study was to investigate the pharmacogenomics of CYP2D6 genotyping in Iranian patients with breast cancer treated with adjuvant TAM. MethodsA peripheral blood sample was obtained to determine the steady-state plasma concentrations of TAM and its metabolites (Endoxifen (EN) and 4-Hydroxytamoxifen (4-OHT)) using high-performance liquid chromatography with fluorescence detection (HPLC-FLU) assay. We detected CYP2D6 * 3, * 4, * 10, and * 17 single nucleotide polymorphisms via polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) method. ResultsA total of 84 Iranian estrogen receptor‑positive breast cancer patients receiving the daily dose of 20 mg tamoxifen were recruited. Although a consequent decrease in the median EN and 4-OHT concentrations was observed by comparing poor or intermediate metabolizer patients with an extensive metabolizer population, this difference did not reach a significant level. The mean plasma EN concentrations in poor and intermediate metabolizers were 46.1% (95% CI, 7.4–27.8%) and 59.4% (95% CI, 11.9–37.3%) of extensive metabolizer subjects, respectively. Poor and intermediate metabolizers had the mean plasma 4-OHT concentrations that were 46.6% (95% CI, 0.9–61.7%) and 73.2% (95% CI, 2.7–93.1%) of those of subjects who were extensive metabolizer, respectively. ConclusionsThe possible role of genotyping in Iranian patients' response to treatment may explain inter-individual differences in the plasma concentrations of active metabolites of TAM.

A systematic review and meta-analysis of the kynurenine pathway of tryptophan metabolism in rheumatic diseases.

https://www.crd.york.ac.uk/prospero, identifier CRD CRD42023443718.

Comparative analysis of signalling pathways in tissue protein metabolism in efficient and non-efficient beef cattle: acute response to an identical single meal size

Protein turnover has been associated to residual feed intake (RFI) in beef cattle. However, this relationship may be confounded by feeding level and affected by the composition of the diet being fed. Our aim was to assess postmortem the protein metabolism signalling pathways in skeletal muscle and liver of 32 Charolais young bulls with extreme RFI phenotypes. Bulls were fed two contrasting diets during the whole fattening period but were subjected to a similar and single nutritional stimulus, induced by their respective concentrate, just prior to slaughter. The key targets were protein degradation (autophagy and ubiquitin) and synthesis signalling pathways through western-blot analysis, as well as hepatic transaminase activity. To ensure a precise assessment of all animals at the same postprandial time, they were provided with a test meal (2.5 kg of either a high-starch and high-protein concentrate or high-fibre and low-protein concentrate) 3 hours prior to slaughter, irrespective of their RFI grouping. Blood and tissues were sampled at the slaughterhouse (3 h and 3 h30 postprandially, respectively). In response to an identical single meal size, efficient RFI animals showed higher (P < 0.05) postprandial plasma β-hydroxybutyrate concentrations and insulinemia (only with the high-starch concentrate) than non-efficient animals. Moreover, efficient RFI bulls had lower muscle (P = 0.04) and liver (P = 0.08) ubiquitin protein abundance (degradation pathway) and tended to have lower alanine transaminase activity in the liver (P = 0.06) compared to non-efficient bulls, regardless of diet. A positive correlation between protein degradation potential and amino acid catabolism was identified in this study (r = 0.52, P = 0.004), which was interpreted as being biologically linked to the RFI phenotype. Efficient RFI bulls also had a faster potential for protein synthesis in the muscle, as indicated by their greater ratio of phosphorylated to total form of ribosomal protein S6 kinase (P = 0.05), regardless of diet. Results on protein synthesis pathway in muscle and plasma metabolite concentrations suggested that efficient RFI cattle may have a faster nutrient absorption and insulin responsiveness after feeding than inefficient cattle. We did not find significant differences in hepatic protein synthesis pathways between the two RFI groups (P > 0.05). Our findings suggest that, in response to an identical single meal size, efficient RFI animals exhibited lower activation of tissue protein degradation pathways and faster muscle protein synthesis activation compared to their inefficient counterparts. This pattern was observed regardless of the composition of the tested meals.