Plasma Concentrations Of Metabolites Research Articles

Defining the molecular response to ischemia-reperfusion injury and remote ischemic preconditioning in human kidney transplantation

Background Ischemia-reperfusion injury (IRI) inevitably occurs during kidney transplantation and extended ischemia is associated with delayed graft function and poor outcomes. Remote ischemic preconditioning (RIPC) is a simple, noninvasive procedure aimed at reducing IRI and improving graft function. Experimental studies have implicated the kynurenine pathway as a protective mechanism behind RIPC. Methods First, paired biopsies from 11 living kidney donors were analyzed to characterize the acute transcriptomic response to IRI. Second, 16 living kidney donors were subjected to either RIPC (n = 9) or no pretreatment (n = 7) to evaluate the impact of RIPC on the transcriptomic response to IRI. Finally, the effect of RIPC on plasma metabolites was analyzed in 49 healthy subjects. Results There was a robust immediate response to IRI in the renal transcriptomes of living-donor kidney transplantation, including activation of the mitogen-activated protein kinase (MAPK) and epidermal growth factor receptor (EGFR) pathways. Preconditioning with RIPC did not significantly alter the transcriptomic response to IRI or the concentration of plasma metabolites. Conclusions The present data validate living-donor kidney transplantation as a suitable model for mechanistic studies of IRI in human kidneys. The failure of RIPC to alter transcriptomic responses or metabolites in the kynurenine pathway raises the question of the robustness of the standard procedure used to induce RIPC, and might explain the mixed results in clinical trials evaluating RIPC as a method to attenuate IRI.

Plasma statin concentrations do not correlate with statin-induced myalgia

Abstract Aims Statins are essential in cardiovascular prevention. Although well-tolerated, patient adherence is often suboptimal due to experienced musculoskeletal symptoms ranging from mild myalgia to rare life-threatening rhabdomyolysis. This study aimed to investigate the relationship between plasma concentrations of statin metabolites in patients experiencing myalgia without rhabdomyolysis. Methods and results Plasma concentrations of statin metabolites were quantitatively assessed using mass spectrometry across three case-control cohorts evaluating statin-induced myalgia. The analysis included a total of 373 patients from the MILANO study (N=85 with self -reported myalgia), the MONTREAL study (N=248 with clinically verified myalgia) and the STOMP study (N=40 with rechallenge-verified statin-induced myalgia). STOMP found no significant difference in the plasma concentrations of statin metabolites between statin naïve patients with myalgia (N=12) taking atorvastatin 80 mg daily and asymptomatic controls (N=28), including upon subsequent statin rechallenge. Both the MILANO and MONTREAL studies showed lower plasma concentrations of statin metabolites in patients with myalgias compared to controls. MILANO showed a significant difference in rosuvastatin lactone concentration in patients with myalgias compared to asymptomatic controls (P = 0.025). Similarly, MONTREAL showed significantly lower mean atorvastatin metabolite concentrations in affected patients versus controls (P values ranging from 0.0073 to 0.037). Atorvastatin dosages in MONTREAL ranged from 5 to 80 mg daily, the most frequent regimens being 20 mg (27% in cases; 24% in controls) and 40 mg (33% in cases; 37% in controls). Creatine kinase levels were measured in all cohorts and were not different between cases and controls. Conclusion Development of myalgias in patients with normal creatine kinase levels is not associated with higher statin metabolite plasma concentrations. Myalgias during statin therapy are not caused by pharmacokinetic abnormalities.

Age-dependent changes in visceral adiposity are associated with decreased plasma levels of DHEA-S in sigma-1 receptor knockout male mice

The sigma-1 receptor (S1R) is involved in intracellular lipid synthesis and transport. Recent studies have shown that its genetic inactivation impairs adipogenic differentiation in vitro. This study investigated the role of S1R in adipose tissue physiology and metabolic health using adult and old WT and S1R KO mice.Visceral fat mass was increased in adult, but not old S1R-KO male mice compared to that of WT mice, despite having similar body weights, food intake, and energy expenditure. The average adipocyte size was 64 % larger in adult KO mice than in adult WT mice. Adult S1R-KO mice showed reduced plasma dehydroepiandrosterone sulfate (DHEA-S) and elevated fasting plasma leptin concentrations. Lipidomic analysis revealed alterations in plasma metabolite concentrations, particularly reduced levels of sphingomyelins, ceramides, phosphatidylcholines, lysophosphatidylcholines, and cholesteryl esters in adult mice. Decreased expression of Pparγ, Adipoq, and Atgl was detected in visceral white adipose tissue (vWAT) isolated from adult KO mice. Additionally, Fabp4 and Adipoq expression levels were significantly lower in KO adipose-derived stromal cells than in WT adipose-derived stromal cells. A fivefold increase in the mitochondrial fatty acid oxidation rate and a 43 % increase in electron transfer coupling capacity were detected in adult S1R-KO vWAT.In summary, our investigation revealed an age-dependent association between increased visceral adiposity and decreased plasma levels of DHEA-S in S1R-deficient male mice. These findings underscore the potential role of S1R in regulating metabolic processes in adipose tissue and suggest that DHEA-S is a potential mediator of adiposity changes in the absence of S1R.

Concentration-QTc analysis of soticlestat in healthy adults: An alternative to a thorough QT study.

This study aimed to examine the cardiac and overall safety and pharmacokinetic (PK) profiles of soticlestat (TAK-935), an oral, first-in-class selective cholesterol 24-hydroxylase inhibitor. Data came from a randomised, phase 1 study of soticlestat in 33 healthy Japanese adults (NCT04461483); 24 adults in Part 1 (single-dose soticlestat 200-1200 mg or placebo) and 9 in Part 2 (soticlestat 100-300 mg twice daily or placebo for 21 days). PK sample collection was paired with 12-lead electrocardiogram data from continuous Holter recordings. The concentration-QTc relationship was analysed using a linear mixed-effects model. QTc prolongation safety margins were determined for two scenarios of calculated high clinical exposures: scenario 1 (NCT05064449) involved coadministration of single-dose soticlestat 300 mg with itraconazole or mefenamic acid and scenario 2 (NCT05098054) involved single-dose soticlestat 300 mg administration in participants with mild/moderate hepatic impairment (implementing a 3-fold dose reduction for moderate severity). Based on concentration-QTc analysis, placebo-corrected change-from-baseline QT values (90% confidence intervals), corrected for heart rate (Fridericia's method), were 0.94 ms (-2.35, 4.23) for soticlestat and 0.63 ms (-3.15, 4.41) for its N-oxide metabolite plasma concentrations at therapeutic doses (soticlestat 300 mg twice daily); safety margins were >2-fold for scenarios of calculated high clinical exposures. No (Part 1) and five (83.3%; Part 2) participants experienced treatment-emergent adverse events (all mild). There was no evidence for QT prolongation with soticlestat at therapeutic doses or in two scenarios of high clinical exposures, which resulted in regulatory agencies waiving requirements of a thorough QT study. Safety/PK findings aligned with previous soticlestat clinical studies.

Liver transcriptome and proteome are modulated by nutrient restriction in early lactation cows challenged with intramammary lipopolysaccharide

The objective was to evaluate the effects of nutrient restriction on liver function 24 h after an intramammary lipopolysaccharide (LPS) challenge in early lactation cows using transcriptomic and proteomic analyses. Multiparous Holstein cows were fed a lactation diet (CONT, n = 8) throughout the study or were switched to a diet diluted with barley straw (48 % DM) for 96 h (REST, n = 8) starting at 24 (18 to 30) days in milk. At 72 h, a healthy rear mammary quarter was infused with 50 μg of LPS in all cows. Blood and liver biopsies were collected at 96 h, corresponding to 24 h after LPS challenge. Liver transcriptome was analyzed with a 44 K bovine microarray and proteome by LC MS/MS. Transcriptomic and proteomic data were analyzed using GeneSpring (moderated t-test with Westfall-Young correction) and the “between subject design”, respectively. Data mining was performed using Panther and Pathway Studio software. By design, the negative energy balance was −68 and −37 MJ/d in REST and CONT, respectively. Plasma non-esterified FAs, and β-hydroxybutyrate were significantly greater in REST compared to CONT, which is consistent with 96 h of nutrient restriction in REST and ketosis induction. We detected 77 and 91 differentially expressed genes at mRNA and protein levels, respectively, between CONT and REST. Genes involved in fatty acid synthesis (e.g.: ACAT, FASN, SCD) were downregulated in REST, whereas those involved in fatty acid oxidation, detoxification, cholesterol synthesis, lipoprotein lipid secretion, and gluconeogenesis (e.g.: ACAD, CPT1A, CPT1B, CPT2) were upregulated. Differentially abundant mRNAs and proteins were consistent with negative energy balance and plasma metabolite concentrations, and reflected a state of intense lipomobilization, glucose deficit and ketogenesis in REST cows. Nutrient restriction did not change in deep liver expression of genes directly involved in immune function 24 h after an intramammary LPS challenge.

127 Effects of maternal pre- and post-partum supplementation of a Bacillus-based DFM on plasma metabolome profile of Bos indicus-influenced heifers and their offspring

Abstract This study evaluated the effects of maternal supplementation during pre- and postpartum of a Bacillus-based direct-fed microbial (DFM) on plasma metabolome of Bos indicus-influenced cow-calf pairs. On d 0, 72 pregnant Brangus crossbred beef heifers (20 to 22 mo of age) were stratified by their initial body weight (BW; 431 ± 31 kg) and body condition score (BCS; 6.0 ± 0.36), and randomly allocated into 1 of 12 bahiagrass pastures (1 ha and 6 heifers/pasture). Treatments were randomly assigned to pastures (6 pastures/treatment) and consisted of heifers supplemented with 1 kg/d of soybean hulls dry matter added (BAC) or not (CON) with a Bacillus-based DFM mixture (Bovacillus; Chr. Hansen A/S, Hørsholm, Denmark) from d 0 to 242 (139 ± 4 d prepartum to 104 ± 4 d postpartum). Calves were weaned on d 242 (96 ± 30 d of age) and then allocated into 1 of 12 drylot pens and limit-fed the same concentrate at 3.25% of BW until day 319. On d 271 and 287, calves were vaccinated against pathogens associated with bovine respiratory disease and Clostridium. Blood samples were collected from all heifers on d 0 and 63 and from all calves on d 271, 274, and 287 to determine the plasma concentration of metabolites using liquid chromatography. The PLS-DA revealed a clear separation of plasma metabolome profile of BAC and CON heifers and offspring. For the heifer metabolome, 66.5% of the treatment separation on d 63 was explained using 3 components (R2 = 0.96), and BAC heifers had increased (P ≤ 0.05) plasma concentration of 17 metabolites, including phosphatidylcholines and amino acids related classes, but decreased (P ≤ 0.05) plasma concentration of 4 metabolites from triglycerides class compared with CON heifers. For the calf metabolome, 45.6 (R2 = 0.95), 56.7 (R2 = 0.95), and 61.3% (R2 = 0.99) of the treatment separation on d 271, 274, and 287, respectively, were explained using 3 components. Plasma concentrations of 9, 10, and 28 metabolites associated with protein and fatty acid metabolism increased (P ≤ 0.05) in BAC vs. CON calves on d 271, 274, and 287, respectively. Compared with CON, BAC calves had increased (P ≤ 0.05) concentration of metabolites from phosphatidylcholines class all days, from amino acids related class on d 274 and 287, and from triglycerides class on d 287. Plasma concentrations of 3 and 6 metabolites from triglycerides class decreased (P ≤ 0.05) in BAC vs. CON calves on d 271 and 274, respectively. Thus, maternal supplementation of Bacillus-based DFM altered the plasma metabolome of heifers and their calves, leading to increased plasma concentrations of phosphatidylcholine and amino acids related classes in heifers and calves, but fluctuating effects on triglycerides class concentrations in calves.

Role of serotonin and serotonergic-related metabolites in the pathogenesis of vasovagal syncope

BackgroundSerotonin is an important neurohormone that regulates vascular tone and autonomic reflexes, though its pathophysiological role in vasovagal syncope (VVS) remains uncertain. ObjectiveThis study sought to explore the involvement of serotonin and serotonergic-related metabolites in the pathogenesis of VVS. MethodsSixty-six patients [mean age 45.6±17.0 years; 33 women (50%)] with recurrent VVS underwent a head-up tilt test (HUTT). Blood samples were collected from all patients in a resting supine position, with an additional sample obtained from HUTT-positive patients during syncope. Plasma and platelet serotonin levels and plasma concentrations of serotonergic-related metabolites—including serotonin’s precursor 5-hydroxytryptophan (5-HTP), major metabolite 5-hydroxyindoleacetic acid, and synthesis source tryptophan—were measured using the liquid chromatography tandem mass spectrometry method. ResultsHUTT was positive in 45 (68.2%) patients and negative in 21 (21.8%) patients. Significant differences were observed in plasma 5-HTP and 5-hydroxyindoleacetic acid levels between HUTT-positive and HUTT-negative patients (P<.001 and P=.040, respectively) as well as before and after syncope (P<.001 for all), whereas no significant changes were found in serotonin and tryptophan levels. Notably, plasma serotonin levels significantly increased during syncope in patients with drug-free VVS (P=.037), and a greater change in serotonin correlated with a shorter time to syncope (R2=0.38; P=.015). Furthermore, certain serotonergic-related metabolites exhibited significant correlations with hemodynamic changes during VVS episodes, with 5-HTP demonstrating the highest sensitivity. ConclusionDespite the unchanged plasma and platelet serotonin levels, certain serotonergic-related metabolites significantly changed and correlated with hemodynamic parameters during VVS episodes, suggesting the potential involvement of an altered serotonergic metabolic pathway in VVS.

Population Pharmacokinetics of Loxoprofen and its alcoholic metabolites in healthy Korean men.

Loxoprofen has been actively used clinically to relieve musculoskeletal pain and inflammatory symptoms. However, there are few reports on quantitative pharmacokinetic (PK) prediction tools and diversity analyzes for loxoprofen within populations. The aim of this study was to identify effective covariates associated with explaining inter-individual PK variability through a population pharmacokinetic (Pop-PK) modeling approach for loxoprofen, and to provide a starting point for establishing scientific dosing regimens. The bioequivalence PK results of loxoprofen performed on 52 healthy Korean men and the physiological and biochemical parameters derived from each individual were used as base data for the development of a Pop-PK model of loxoprofen. In order to simultaneously predict the PKs of the active form according to loxoprofen exposure, previously reported PK results of trans-alcohol loxoprofen, an active metabolite of loxoprofen, were used to expand the model. The Pop-PK profiles of loxoprofen were described in terms of the basic structure of a non-sequential two absorption with 2-disposition compartment, and for inter-individual PK variations, peripheral compartment volume of distribution could be correlated with body surface area (BSA), and central compartment clearance with creatinine clearance (CrCL) and albumin levels. As a result of the model simulation, the concentrations of loxoprofen and its alcoholic metabolites in plasma significantly decreased as CrCL and albumin levels increased and decreased, respectively. On the other hand, it was confirmed that the higher the BSA, the greater the distribution of loxoprofen to the periphery, and the minimum concentrations of loxoprofen and alcoholic metabolites in plasma in steady-state increased by approximately 1.78-2 times, while the fluctuation between maximum and minimum concentrations decreased. The results suggest that patients with large BSA, impaired renal function, and high serum albumin levels may have significantly higher plasma exposure to loxoprofen and trans-alcohol loxoprofen. It was also suggested that the potential side effects in the gastrointestinal system and various tissues and the level of exposure in plasma due to long-term application of loxoprofen in this patient group could be causally explained. This study provides a very useful starting point for a scientific precision medicine approach to loxoprofen by discovering effective covariates and establishing a quantitative model that can explain the diversity of loxoprofen PKs within the population. The clinical study protocol used in this study was thoroughly reviewed and approved by the Institutional Review Board of the Institute of Bioequivalence and Bridging Study, Chonnam National University, Gwangju, Republic of Korea. The bioequivalence study permit numbers are as follows: 041113; 10.15.2004.

A Cross-Sectional Study Comparing Oxidative Stress in Patients with Epilepsy Treated with Old and New Generation Antiseizure Medications.

Background and Objectives: Oxidative stress resulting from a disturbance of the endogenous redox system is suspected in numerous diseases of the central nervous system, including epilepsy. In addition, antiseizure medications (ASMs), especially those of the old generation, may further increase oxidative stress. To evaluate the effects of ASM generation on oxidative stress, we conducted a cross-sectional study in patients with epilepsy treated with old, new, and polytherapy. Materials and Methods: The antioxidant activity of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase, as well as the concentrations of malondialdehyde, protein carbonyl, nitrate, nitrite, and glutathione in reduced and oxidized forms, were measured in 49 patients with epilepsy and 14 healthy controls. In addition, the plasma concentrations of ASMs and metabolites of carbamazepine and valproic acid were measured in the patients. Results: Patients with epilepsy showed increased activities of superoxide dismutase and catalase (p < 0.001), concentrations of glutathione disulfide and markers of nitric oxide metabolism (p < 0.001), and decreased activities of glutathione peroxidase, glutathione reductase, glutathione, and nitrite concentrations (p ≤ 0.005) compared to healthy controls. A comparison of ASM generations revealed increased levels of superoxide dismutase and catalase (p ≤ 0.007) and decreased levels of glutathione peroxidase and glutathione reductase (p ≤ 0.01) in patients treated with old ASMs compared to those treated with new generation ASMs. In addition, an increase in protein carbonyl and nitric oxide metabolites (p ≤ 0.002) was observed in patients treated with old generation ASMs compared to those treated with new generation ASMs. Most oxidative stress parameters in patients receiving polytherapy with ASMs were intermediate between the results of patients treated with the old and new generations of ASMs. Conclusions: An increase in oxidative stress markers and modulation of antioxidant enzyme activities was observed in patients with epilepsy compared to controls. The results of our study showed significantly higher oxidative stress in patients treated with old ASMs compared to those treated with new generation ASMs.

Multiple-Dose Pharmacokinetics and Safety of Mitragynine, the Major Alkaloid of Kratom, in Rats.

This study reports the steady-state pharmacokinetic parameters for mitragynine and characterizes its elimination in male and female rats. Four male and female rats were dosed q12h with 40 mg/kg, and orally administered mitragynine for 5 and 6 days, respectively. Using a validated ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method, the plasma concentrations of mitragynine, its metabolites (7-hydroxymitragynine, 9-hydroxycorynantheidine, and mitragynine acid), and a non-CYP oxidation product (3-dehydromitragynine) were determined at various time points. Sex differences in pharmacokinetics were observed, with females demonstrating significantly higher systemic exposure of mitragynine than males. The mitragynine area under the curve normalized by the dose interval (AUC/τ) was 6741.6 ± 869.5 h*ng/mL in female rats and 1808.9 ± 191.3 h*ng/mL in males (p < 0.05). Both sexes produced similar metabolite profiles; the major metabolites were mitragynine acid and 9-hydroxycorynantheidine. 7-Hydroxymitragynine was a minor metabolite. However, higher exposure (AUCs) and the maximum plasma concentrations (C max) of active metabolites, 7-hydroxymitragynine and 9-hydroxycorynantheidine, were observed in female rats and exhibited substantial sex differences. Renal clearance of mitragynine (CLr) was low (0.64 ± 0.3 mL/h in males and 0.98 ± 0.4 mL/h in females), and unchanged mitragynine accounted for <1% of the dose excreted in feces (both sexes). The clinical chemistry, complete blood count, and hematological test results reported no abnormal hematological findings after multiple dosing in either sex.

Altered bile acid and correlations with gut microbiome in transition dairy cows with different glucose and lipid metabolism status

The transition from pregnancy to lactation is critical in dairy cows. Among others, dairy cows experience a metabolic stress due to a large change in glucose and lipid metabolism. Recent studies revealed that bile acids (BA), other than being involved in both the emulsification and solubilization of fats during intestinal absorption, can also affect the metabolism of glucose and lipids, both directly or indirectly by affecting the gut microbiota. Thus, we used untargeted and targeted metabolomics and 16S rRNA gene sequencing approaches to investigate the concentration of plasma metabolites and BA, the composition of the rectum microbial community, and assess their interaction in transition dairy cows. In Experiment 1, we investigated BA and other blood parameters and gut microbiota in dairy cows without clinical diseases during the transition period, which can be seen as well adapted to the challenge of changed glucose and lipid metabolism. As expected, we detected an increased plasma concentrations of BHB and nonesterified fatty acids (NEFA) but decreased concentrations of glucose, cholesterol, and triglycerides (TG). Untargeted metabolomic analysis of the plasma revealed primary BA biosynthesis was one of the affected pathways, and was consistent with the increased concentration of BA in the plasma. A correlation approach revealed a complex association between BA and microbiota with the host plasma concentration of glucose and lipid metabolites. Among BA, chenodeoxycholic acid derivates such as glycolithocholic acid, taurolithocholic acid, lithocholic acid, taurochenodeoxycholic acid, and taurodeoxycholic acid were the main hub nodes connecting microbe and blood metabolites (such as glucose, TG, and NEFA). In Experiment 2, we investigated early postpartum dairy cows with or without hyperketonemia (HPK). As expected, HPK cows had increased concentration of NEFA and decreased concentrations of glucose and triglycerides. The untargeted metabolomic analysis of the plasma revealed that primary BA biosynthesis was also one of the affected pathways. Even though the BA concentration was similar among the 2 groups, the profiles of taurine-conjugated BA changed significantly. A correlation analysis also revealed an association between BA and microbiota with the concentration in plasma of glucose and lipid metabolites (such as BHB). Among BA, cholic acid and its derivates such as taurocholic acid, tauro α-muricholic acid, and taurodeoxycholic acid were the main hub nodes connecting microbe and blood metabolites. Our results indicated an association between BA, intestinal microbe, and glucose and lipid metabolism in transition dairy cows. These findings provide new insight into the adaptation mechanisms of dairy cows during the transition period.

Quantification of Efavirenz Hydroxymetabolites in Human Plasma Using LC-HRMS/MS.

Efavirenz (EFV) is a drug used to treat HIV. Low plasma concentrations of EFV result in suboptimal viral suppression, whereas high concentrations can cause adverse neuropsychiatric side reactions. Some studies have identified a correlation between the plasma concentrations of EFV metabolites and neurotoxicity. To our knowledge, no studies have investigated the metabolism of EFV in young children and its effect on treatment outcomes. Therefore, the aim of this study was to develop and validate a method for quantifying EFV and its metabolites in human plasma derived from children. Sample preparation was performed using protein precipitation of 100 µL plasma. Thereafter, an aliquot of the supernatant was used to quantify EFV, 7-hydroxyefavirenz (7-OH-EFV), 8-hydroxyefavirenz (8-OH-EFV), and a newly discovered metabolite ("EFAdeg") associated with 8-OH-EFV. A second aliquot of the supernatant was hydrolyzed using β-glucuronidase/arylsulfatase and used with the first aliquot to quantify phase II metabolites. The analyses were performed using a Dionex Ultimate 3000RS LC-system coupled with a Q Exactive Orbitrap mass spectrometer. The method has a measuring range of 100-50,000 ng/mL (EFV, 8-OH-EFV), 125-25,000 ng/mL (7-OH-EFV), and 200-10,000 ng/mL ("EFAdeg"). All criteria of the European Medicines Agency guidelines regarding precision, accuracy, and selectivity were met. Of note, carryover must be considered for 8-OH-EFV. Overall, the validated method was successfully applied to plasma samples obtained from children and confirmed the presence of the newly discovered metabolite, "EFAdeg." An LC-HRMS/MS method for the quantification of EFV and its phase I and II metabolites was developed and validated. This method is suitable for analyzing plasma samples from children. Furthermore, studies using this method identified an additional metabolite that may influence the concentration of 8-OH-EFV in patient samples.

Mechanisms contributing to lactose and sucrose-induced postprandial lipaemia

Fructose-containing sugars can exaggerate postprandial lipaemia and stimulate hepatic de novo lipogenesis (DNL) when compared to glucose-based carbohydrates(1). Galactose has recently been shown to increase postprandial lipaemia compared to glucose(2), but mechanisms remain uncharacterised. The aim of this study was to assess the effect and mechanisms of lactose-induced lipaemia.Twenty-four non-obese adults (12 male and 12 female) completed three trials in a randomised, crossover design (28 ± 7-day washout). During trials, participants consumed test drinks containing 50 g fat with 100 g of carbohydrate. The control carbohydrate was a glucose polymer (maltodextrin), the experimental carbohydrate was galactose-containing carbohydrate (lactose) and the active comparator was fructose-containing carbohydrate (sucrose). Hepatic DNL was assessed by the 2H2O method and [U-13C]-palmitate was added to the test drink to trace the fate of the ingested fat. Blood and breath samples were taken to determine plasma metabolite and hormone concentrations, in addition to plasma and breath 2H and 13C enrichments. Data were converted into incremental under the curve (iAUC) and were checked for normality by visual inspection of residuals. Differences between trials were assessed by one-way ANOVA. Where a main effect of trial was detected, post- hoc t-tests were performed to determine which trials differed from lactose according to the principle of closed-loop testing.The plasma triacylglycerol iAUC (mean ± SD) in response to maltodextrin was 51 ± 68 mmol/L*360 min. Following lactose ingestion, plasma triacylglycerol iAUC increased to 98 ± 88 mmol/L*360 min (p&lt;0.001 vs maltodextrin), which was comparable to sucrose [90 ± 95 mmol/L*360 min (p=0.41 vs lactose)]. Hepatic DNL in response to maltodextrin was 6.6 ± 3.0%. Following ingestion of lactose, hepatic DNL increased to 12.4 ± 6.9% (p=0.02 vs maltodextrin), which was comparable to sucrose [12.2 ± 6.9% (p=0.96 vs lactose)]. Exhaled 13CO2 in response to maltodextrin was 10.4 ± 4.1 mmol/kgFFM*360 min. Following ingestion of lactose, exhaled 13CO2 was 8.8 ± 4.9 mmol/kgFFM*360 min (p=0.09 vs maltodextrin), which was lower than sucrose [11.1 ± 3.9 mmol/kgFFM*360 min (p=0.01 vs lactose)].These data are consistent with the hypothesis that hepatic de novo lipogenesis contributes to both lactose and sucrose-induced lipaemia and provide a rationale to investigate the longer-term effects of lactose and sucrose on metabolism.

Energy supply during nocturnal endurance flight of migrant birds: effect of energy stores and flight behaviour

BackgroundMigrating birds fly non-stop for hours or even for days. They rely mainly on fat as fuel complemented by a certain amount of protein. Studies on homing pigeons and birds flying in a wind-tunnel suggest that the shares of fat and protein on total energy expenditure vary with flight duration and body fat stores. Also, flight behaviour, such as descending flight, is expected to affect metabolism. However, studies on free flying migrant birds under natural conditions are lacking.MethodsOn a Swiss Alpine pass, we caught three species of nocturnal migrant passerines out of their natural migratory flight. Since most night migrants start soon after dusk, we used time since dusk as a measure of flight duration. We used plasma concentrations of metabolites of the fat, protein, and carbohydrate metabolism as indicators of relative fuel use. We used flight altitudes of birds tracked with radar and with atmospheric pressure loggers to characterize flight behaviour.ResultsThe indicators of fat catabolism (triglycerides, very low-density lipoproteins, glycerol) were positively correlated with body energy stores, supporting earlier findings that birds with high fat stores have a higher fat catabolism. As expected, plasma levels of triglycerides, very low-density lipoproteins, glycerol and ß-hydroxy-butyrate increased at the beginning of the night, indicating that nocturnal migrants increased their fat metabolism directly after take-off. Surprisingly, fat catabolism as well as glucose levels decreased in the second half of the night. Data from radar observations showed that the number of birds aloft, their mean height above ground and vertical flight speed decreased after midnight. Together with the findings from atmospheric pressure-loggers put on three species, this shows that nocturnal migrants migrating over continental Europe descend slowly during about 1.5 h before final landfall at night, which results in 11–30% energy savings according to current flight models.ConclusionsWe suggest that this slow descent reduces energy demands to an extent which is noticeable in the plasma concentration of lipid, protein, and carbohydrate metabolites. The slow descent may facilitate the search for a suitable resting habitat and serve to refill glycogen stores needed for foraging and predator escape when landed.

Investigation of virginiamycin to improve health of growing and finishing steers: I. Effects on ruminal acidosis and liver health*

ObjectiveOur objective was to observe the effects of the interrelationship among virginiamycin (VM) inclusion (240 mg/d), ruminal pH dynamics, and hepatic plasma metabolites on rumen and animal health during a 150-d feeding trial. Materials and MethodsSteers (304 ± 27 kg; n = 120) were assigned randomly to 1 of 6 dietary treatments: no VM (T000); VM for the last 50 d (T001); VM for the last 100 d (T011); VM for the first 50 d (T100); VM for the first 100 d (T110); and VM for 150 d (T111). All animals were orally administered 2 indwelling rumen pH and temperature recording boli on d 0 and 84. Blood samples were collected via jugular venipuncture on d −7, 28, 56, 84, 112, and 140, and plasma was analyzed for concentrations of albumin, alkaline phosphatase, direct bilirubin, total bilirubin, gamma-glutamyl transferase, and total protein using an automated blood analyzer. Concurrently, haptoglobin (HPT) was measured following a colorimetric method based on peroxidase activity. A random coefficients model with pen and animals within treatment as a random effect was used. Results and DiscussionAnimals that received VM for the first 100 d (T110 and T111) had greater mean ruminal pH during d 50 to 100 when compared with animals that did not receive VM (T000 and T001; 6.12 vs. 6.00, respectively). Moreover, T111 tended to have less time under pH 5.8 (3.01 h/d) when compared with T100 and T001 (5.83 and 6.45 h/d, respectively). At slaughter, overall, 3.36% of cattle in the study were identified with liver abscesses (A and A−), and 24.3% had lung lesions. Plasma metabolite concentrations before slaughter did not predict the presence of liver abscesses (P ≥ 0.182). Based on acute phase responses, HPT was notably lower on d 84 after diet transition in VM-treated animals (46.1 vs. 68.9 mg/L). Additionally, VM inclusion boosted indicators of overall health with greater alkaline phosphatase levels and albumin-toglobulin ratios. Implications and ApplicationsVirginiamycin has practical implications for rumen health and overall cattle health, where supplementation during the whole growing to finishing phases was more effective in capturing its full potential.

Morphology and metabolic traits related to swimming performance in Australasian snapper (Chrysophrys auratus) selected for fast growth.

Changes in body shape are linked to swimming performance and become relevant for selective breeding programmes in cultured finfish. We studied how the selection for fast growth could affect phenotypes by investigating the relationship between swimming performance and body shape. We also investigated how swimming might affect plasma metabolite concentrations. Critical swimming speed (UCrit), body traits (e.g., BW, body weight; BL, body length; K, condition factor), and plasma lactate and glucose concentrations were evaluated in two cohorts of Australasian snapper (Chrysophrys auratus): one derived from wild broodstock (F1), and the other selected for fast growth (F4). UCrit tests (n = 8) were applied in groups of 10 snapper of similar BW (71.7 g) and BL (14.6 cm). The absolute or relative UCrit values of both cohorts were similar (0.702 m⋅s-1 and 4.795 BL⋅s-1, respectively), despite the F4 cohort displaying a higher K. A positive correlation between K and absolute UCrit (Pearson's r = 0.414) was detected in the F4 cohort, but not in the F1 cohort, which may be linked to differences in body shape. A negative correlation between relative UCrit and body size (Pearson's r between -0.682 and -0.501), but no correlation between absolute UCrit and body size, was displayed in both cohorts. Plasma lactate and glucose concentrations were higher in the F4 cohort at UCrit. Whether a longer selective breeding programme could result in more changes in body shape, potentially affecting swimming performance, should be explored, along with the potential outcomes of the differences in metabolic traits detected.

Metabolic predictors of COVID-19 mortality and severity: a survival analysis.

The global healthcare burden of COVID-19 pandemic has been unprecedented with a high mortality. Metabolomics, a powerful technique, has been increasingly utilized to study the host response to infections and to understand the progression of multi-system disorders such as COVID-19. Analysis of the host metabolites in response to SARS-CoV-2 infection can provide a snapshot of the endogenous metabolic landscape of the host and its role in shaping the interaction with SARS-CoV-2. Disease severity and consequently the clinical outcomes may be associated with a metabolic imbalance related to amino acids, lipids, and energy-generating pathways. Hence, the host metabolome can help predict potential clinical risks and outcomes. In this prospective study, using a targeted metabolomics approach, we studied the metabolic signature in 154 COVID-19 patients (males=138, age range 48-69 yrs) and related it to disease severity and mortality. Blood plasma concentrations of metabolites were quantified through LC-MS using MxP Quant 500 kit, which has a coverage of 630 metabolites from 26 biochemical classes including distinct classes of lipids and small organic molecules. We then employed Kaplan-Meier survival analysis to investigate the correlation between various metabolic markers, disease severity and patient outcomes. A comparison of survival outcomes between individuals with high levels of various metabolites (amino acids, tryptophan, kynurenine, serotonin, creatine, SDMA, ADMA, 1-MH and carnitine palmitoyltransferase 1 and 2 enzymes) and those with low levels revealed statistically significant differences in survival outcomes. We further used four key metabolic markers (tryptophan, kynurenine, asymmetric dimethylarginine, and 1-Methylhistidine) to develop a COVID-19 mortality risk model through the application of multiple machine-learning methods. Metabolomics analysis revealed distinct metabolic signatures among different severity groups, reflecting discernible alterations in amino acid levels and perturbations in tryptophan metabolism. Notably, critical patients exhibited higher levels of short chain acylcarnitines, concomitant with higher concentrations of SDMA, ADMA, and 1-MH in severe cases and non-survivors. Conversely, levels of 3-methylhistidine were lower in this context.

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 &amp;gt;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&amp;lt;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.