Plasma Arginine Concentrations Research Articles

Effect of dietary arginine to lysine ratios on productive performance, meat quality, plasma and muscle metabolomics profile in fast-growing broiler chickens

BackgroundDue to the important functions of arginine in poultry, it should be questioned whether the currently adopted dietary Arg:Lys ratios are sufficient to meet the modern broiler requirement in arginine. The present study aimed, therefore, to evaluate the effects of the dietary supplementation of L-arginine in a commercial broiler diet on productive performance, breast meat quality attributes, incidence and severity of breast muscle myopathies and foot pad dermatitis (FPD), and plasma and muscle metabolomics profile in fast-growing broilers.ResultsA total of 1,170 1-day-old Ross 308 male chicks was divided into two experimental groups of 9 replicates each fed either a commercial basal diet (CON, digestible Arg:Lys ratio of 1.05, 1.05, 1.06 and 1.07 in each feeding phase, respectively) or the same basal diet supplemented on-top with crystalline L-arginine (ARG, digestible Arg:Lys ratio of 1.15, 1.15, 1.16 and 1.17, respectively). Productive parameters were determined at the end of each feeding phase (12, 22, 33, 43 d). At slaughter (43 d), incidence and severity of FPD and breast myopathies were assessed, while plasma and breast muscle samples were collected and analyzed by proton nuclear magnetic resonance-spectroscopy. The dietary supplementation of arginine significantly reduced cumulative feed conversion ratio compared to the control diet at 12 d (1.352 vs. 1.401, P < 0.05), 22 d (1.398 vs. 1.420; P < 0.01) and 33 d (1.494 vs. 1.524; P < 0.05), and also tended to improve it in the overall period of trial (1.646 vs. 1.675; P = 0.09). Body weight was significantly increased in ARG compared to CON group at 33 d (1,884 vs. 1,829 g; P < 0.05). No significant effect was observed on meat quality attributes, breast myopathies and FPD occurrence. ARG birds showed significantly higher plasma concentration of arginine and leucine, and lower of acetoacetate, glutamate, adenosine and proline. Arginine and acetate concentrations were higher, whereas acetone and inosine levels were lower in the breast of ARG birds (P < 0.05).ConclusionsTaken together, these data showed that increased digestible Arg:Lys ratio had positive effects on feed efficiency in broiler chickens probably via modulation of metabolites that play key roles in energy and protein metabolism.

Therapeutic regimen of l-arginine for MELAS: 9-year, prospective, multicenter, clinical research

ObjectiveTo examine the efficacy and safety of the therapeutic regimen using oral and intravenous l-arginine for pediatric and adult patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS).MethodsIn the presence and absence of an ictus of stroke-like episodes within 6 h prior to efficacy assessment, we correspondingly conducted the systematic administration of oral and intravenous l-arginine to 15 and 10 patients with MELAS in two, 2-year, prospective, multicenter clinical trials at 10 medical institutions in Japan. Subsequently, patients were followed up for 7 years. The primary endpoint in the clinical trial of oral l-arginine was the MELAS scale, while that for intravenous l-arginine was the improvement rates of headache and nausea/vomiting at 2 h after completion of the initial intravenous administration. The relationships between the ictuses of stroke-like episodes and plasma arginine concentrations were examined.ResultsOral l-arginine extended the interictal phase (p = 0.0625) and decreased the incidence and severity of ictuses. Intravenous l-arginine improved the rates of four major symptoms—headache, nausea/vomiting, impaired consciousness, and visual disturbance. The maximal plasma arginine concentration was 167 μmol/L when an ictus developed. Neither death nor bedriddenness occurred during the 2-year clinical trials, and the latter did not develop during the 7-year follow-up despite the progressively neurodegenerative and eventually life-threatening nature of MELAS. No treatment-related adverse events occurred, and the formulations of l-arginine were well tolerated.ConclusionsThe systematic administration of oral and intravenous l-arginine may be therapeutically beneficial and clinically useful for patients with MELAS.

Prolonged amino acid infusion into intrauterine growth-restricted fetal sheep increases leucine oxidation rates.

Overcoming impaired growth in an intrauterine growth-restricted (IUGR) fetus has potential to improve neonatal morbidity, long-term growth, and metabolic health outcomes. The extent to which fetal anabolic capacity persists as the IUGR condition progresses is not known. We subjected fetal sheep to chronic placental insufficiency and tested whether prolonged amino acid infusion would increase protein accretion in these IUGR fetuses. IUGR fetal sheep were infused for 10 days with either mixed amino acids providing ~2 g·kg-1·day-1 (IUGR-AA) or saline (IUGR-Sal) during late gestation. At the end of the infusion, fetal plasma leucine, isoleucine, lysine, methionine, and arginine concentrations were higher in the IUGR-AA than IUGR-Sal group ( P < 0.05). Fetal plasma glucose, oxygen, insulin, IGF-1, cortisol, and norepinephrine concentrations were similar between IUGR groups, but glucagon concentrations were fourfold higher in the IUGR-AA group ( P < 0.05). Net umbilical amino acid uptake rate did not differ between IUGR groups; thus the total amino acid delivery rate (net umbilical amino acid uptake + infusion rate) was higher in the IUGR-AA than IUGR-Sal group (30 ± 4 vs. 19 ± 1 μmol·kg-1·min-1, P < 0.05). Net umbilical glucose, lactate, and oxygen uptake rates were similar between IUGR groups. Fetal leucine oxidation rate, measured using a leucine tracer, was higher in the IUGR-AA than IUGR-Sal group (2.5 ± 0.3 vs. 1.7 ± 0.3 μmol·kg-1·min-1, P < 0.05). Fetal protein accretion rate was not statistically different between the IUGR groups (1.6 ± 0.4 and 0.8 ± 0.3 μmol·kg-1·min-1 in IUGR-AA and IUGR-Sal, respectively) due to variability in response to amino acids. Prolonged amino acid infusion into IUGR fetal sheep increased leucine oxidation rates with variable anabolic response.

Abstract B33: Expansion study of pegylated arginine deiminase (ADI-PEG20), pemetrexed, and cisplatin in patients with ASS1-deficient non-squamous non-small cell lung cancer (TRAP)

Abstract Background: Loss of the metabolic tumor suppressor argininosuccinate synthetase 1 (ASS1) sensitizes non-squamous non-small cell lung cancer (NSCLC) cells to arginine deprivation with pegylated arginine deiminase (ADI-PEG20), which also disrupts thymidine pools and potentiates pemetrexed (Pem) cytotoxicity. In the phase I dose-escalation TRAP study (NCT02029690) we showed that ADI-PEG20 with first-line PEM and cisplatin (Cis) chemotherapy (ADIPemCis) produced a 100% disease control rate (DCR) (n = 9) of ASS1-deficient thoracic cancers, with no additional toxicity (Beddowes et al., 2017). Here, we present the TRAP expansion cohort experience in non-squamous NSCLC. Methods: Good-performance (ECOG 0-1) NSCLC patients (pts) with nonresectable disease were enrolled in a phase I TRAP expansion cohort at the maximum tolerated dose (MTD) of ADIPemCis, using tumoral ASS1 loss as a selection biomarker. Pem (500mg/m2) and Cis (75mg/m2) were given every 3 weeks with weekly IM ADI-PEG20 (36mg/m2) for a maximum of 4 cycles with maintenance ADI-PEG20 or Pem in responding pts. Primary endpoint was tumor response rate (RECIST 1.1), with secondary endpoints including progression-free survival (PFS), overall survival (OS), and toxicity. We measured plasma arginine and citrulline concentrations, ADI-PEG20 antibodies, early molecular responses by 18-FLT-PET/CT, and biopsied pts on progression to explore resistance mechanisms. Results: 21 ASS1-deficient non-squamous NSCLC pts (median age 60) were enrolled out of 70 screened pts; 14% (3/21) had stable brain metastases at entry. Plasma arginine decreased with a reciprocal increase in plasma citrulline. The partial response rate was 48% (n=10/21) with a DCR of 85.7% (n=18/21). Median PFS was 2.6 months and median OS was 5.3 months. 23.8% (n=5/21) pts experienced grade 3/4 treatment-related toxicities, the most common being non-febrile neutropenia (14.3%). A partial metabolic response was detected in 57.1% (n=4/7) pts by 24 hrs of arginine deprivation using 18-FLT-PET/CT with EORTC response criteria. Upregulation of ASS1 expression was observed in 1/3 biopsies on progression. Conclusions: The ADIPemCis regimen is active in ASS1-deficient non-squamous NSCLC pts with a higher than expected response rate. However, the short survival (PFS and OS) compared with ASS1-agnostic historical controls indicates that ASS1 loss selects for a biologically more aggressive phenotype of NSCLC. Further studies are warranted exploring rationale combinations with ADIPemCis in patients with ASS1-deficient non-squamous NSCLC. Citation Format: Melissa Phillips, Teresa Szyszko, Peter Hall, Sukaina Rashid, Ramsay Khadeir, Louise Lim, Jeremy Steele, John Conibear, Paula Wells, Stephen Ellis, Xiaoxing Feng, Jim Thomson, Amanda Johnston, Bor-Wen Wu, John Bomalaski, Simon Pacey, Gary Cook, Peter Szlosarek. Expansion study of pegylated arginine deiminase (ADI-PEG20), pemetrexed, and cisplatin in patients with ASS1-deficient non-squamous non-small cell lung cancer (TRAP) [abstract]. In: Proceedings of the Fifth AACR-IASLC International Joint Conference: Lung Cancer Translational Science from the Bench to the Clinic; Jan 8-11, 2018; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(17_Suppl):Abstract nr B33.

Plasma Homoarginine Concentrations According to Use of Hormonal Contraception

Estrogen is a potent vasodilator through activation of endothelial nitric oxide synthase (eNOS). Arginine and its homologue homoarginine are substrates for NOS, while asymmetric dimethylarginine (ADMA) is a NOS inhibitor. Healthy, never-pregnant women aged 18 to 40 years (n = 158) were categorized according to use of hormonal contraception into non-users (n = 76), users of estrogen contraceptives (EC-users, n = 58) and users of progestins-only contraceptives (PC-users, n = 24). Plasma homoarginine, arginine, ADMA and SDMA concentrations were assayed using a LC-MS/MS method. Compared to non-users, EC users had higher plasma homoarginine (median (interquartile range) 1.63 (1.24, 2.04) vs. 2.39 (2.05, 2.85) µmol/L, p < 0.001), lower arginine (80.8 (72.4, 94.3) vs. 72.1 (62.9, 85.1) µmol/L, p = 0.008) and ADMA (0.52 (0.46, 0.59) vs. 0.48 (0.42, 0.54) µmol/L, p = 0.003) concentrations. The lowest median plasma homoarginine concentration (1.34 (0.92, 1.75) µmol) was seen in PC-users. No differences were seen in SDMA concentrations according to use of hormonal contraception. In healthy, never-pregnant women aged 18 to 40 years, use of estrogen containing contraception was associated with significantly higher plasma concentrations of homoarginine and lower plasma concentrations of arginine and ADMA as compared to non-users, while the lowest plasma homoarginine concentrations were seen in progestin-only users. Whether the observed changes in relation to use of hormonal contraception have an impact on cardiovascular status, should be evaluated in an intervention study.

Maternal dietary supplementation of arginine increases the ratio of total cloned piglets born to total transferred cloned embryos by improving the pregnancy rate of recipient sows

The extremely low full-term developmental efficiency of cloned pig embryos limits the practical application of pig cloning techniques. Maternal dietary supplementation of the nutritionally important amino acid, arginine, can enhance prenatal developmental rate of in vivo fertilization-derived pig embryos. It was hypothesized that maternal dietary addition of arginine can also improve the developmental capacity of cloned pig embryos. To test this hypothesis, there was a comparison of the reproductive performance between recipient sows fed an L-arginine-supplemented diet (L-Arg group) and those fed the control diet (control group). There was a subsequent comparison of the developmental indexes of cloned piglets farrowed in the L-Arg and control groups of surrogate sows. Dietary supplementation of L-arginine during gestation days 14–75 increased the plasma concentrations of arginine and arginine metabolites, including nitric oxide, spermidine, and putrescine in recipient sows of transferred cloned pig embryos. Although maternal arginine addition did not affect the birth weight and placental development indexes of newborn cloned piglets, it significantly increased the ratio of total cloned piglets born to total transferred cloned pig embryos by increasing the pregnancy rate of recipient sows. The results of this study suggest that nutritional management of recipient sows is an effective approach to improve the developmental rate of cloned pig embryos.

Arginase inhibition prevents the development of hypertension and improves insulin resistance in obese rats.

This study investigated the temporal activation of arginase in obese Zucker rats (ZR) and determined if arginase inhibition prevents the development of hypertension and improves insulin resistance in these animals. Arginase activity, plasma arginine and nitric oxide (NO) concentration, blood pressure, and insulin resistance were measured in lean and obese animals. There was a chronological increase in vascular and plasma arginase activity in obese ZR beginning at 8weeks of age. The increase in arginase activity in obese animals was associated with a decrease in insulin sensitivity and circulating levels of arginine and NO. The rise in arginase activity also preceded the increase in blood pressure in obese ZR detected at 12weeks of age. Chronic treatment of 8-week-old obese animals with an arginase inhibitor or L-arginine for 4weeks prevented the development of hypertension and improved plasma concentrations of arginine and NO. Arginase inhibition also improved insulin sensitivity in obese ZR while L-arginine supplementation had no effect. In conclusion, arginase inhibition prevents the development of hypertension and improves insulin sensitivity while L-arginine administration only mitigates hypertension in obese animals. Arginase represents a promising therapeutic target in ameliorating obesity-associated vascular and metabolic dysfunction.

Abstract B003: Development of OAT-1746, a novel arginase 1 and 2 inhibitor for cancer immunotherapy

Abstract Depletion of arginine represents an important mechanism of immunosuppression, and high plasma and tumor arginase (ARG) activity has been demonstrated in patients with a wide spectrum of cancers and correlated with a poor prognosis. Low arginine levels inhibit proliferation and activation of cytotoxic T and NK cells. Preclinical and clinical studies show that simultaneous interference with multiple mechanisms of immunosuppression results in a strongly improved antitumor efficacy. In this context, we have developed OAT-1746, a novel, potent, and selective small-molecule inhibitor of ARG1 and ARG2 with profound antitumor efficacy as a monotherapy and in combinations with gemcitabine and PD-L1 inhibitor. The IC50 of OAT-1746 was determined against the recombinant human and murine ARG1 and ARG2. Cellular activity was evaluated in M2-polarized, bone marrow-derived murine macrophages, and CHO cells transfected with human ARG1 or ARG2. The in vivo antitumor efficacy of OAT-1746 was evaluated in syngeneic mouse models and in an orthotopic C6 rat glioma model after oral administration. In the rat model, C6 glioma cells were implanted by stereotactic intracranial inoculation and the tumor size was measured by bioluminescence in vivo imaging or immunohistochemistry. Quantitative real-time PCR was used to determine inflammatory markers. The tumor arginase activity was assessed using the urea detection assay. L-Arginine and drug levels in plasma and tumor were evaluated by LC/MS method. We have developed potent, selective, orally active inhibitors of ARG1 and ARG2. The clinical candidate, OAT-1746, has IC50=32 nM and 50 nM against human ARG1 and ARG2, respectively, and a potent cellular activity (M2 macrophages IC50=32 nM, CHO-K1 hARG1 IC50=55 nM). In vivo, OAT-1746 showed good pharmacologic properties and demonstrated significant antitumor efficacy as a monotherapy in 4 tumor models: B16 (melanoma), LLC (lung carcinoma), CT26 (CRC), and C6 glioma with TGI=34-53%. The antitumor efficacy correlated with sustained pharmacodynamic (PD) effects: suppression of tumor arginase activity and 3-6 fold increases in plasma and tumor arginine concentrations. Induction of inflammatory markers in tumors confirmed reversal of immunosuppression. Combinations of OAT-1746 with PD-L1 checkpoint inhibitor and gemcitabine showed increased efficacy. Administration of OAT-1746 with anti-PD-L1 antibody resulted in a “controlled” tumor growth with 55% of tumors remaining under 500 mm3 at day 24 versus 36% for PD-L1 monotherapy. Full regression was observed in 20% of the animals treated in combination with gemcitabine in comparison to 0% for monotherapy. OAT-1746 also demonstrated efficacy and PD effects in the orthotopic model of GBM, confirming its ability to cross the blood-brain barrier. Together these results support the clinical development of OAT-1746 for cancer therapy. Citation Format: Paulina Seweryna Stanczak, Marcin Mikolaj Grzybowski, Paulina Wolska, Anna Maria Zdziarska, Marcin Mazurkiewicz, Paulina Pilanc, Anna Gieryng, Bozena Kaminska, Anna Gzik, Marek Dziegielewski, Karol Jedrzejczak, Bartlomiej Borek, Roman Blaszczyk, Adam Golebiowski, Pawel Dobrzanski, Karolina Dzwonek. Development of OAT-1746, a novel arginase 1 and 2 inhibitor for cancer immunotherapy [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B003.

Amniotic Fluid Arginine from Gestational Weeks 13 to 15 Is a Predictor of Birth Weight, Length, and Head Circumference.

Arginine is a constituent of proteins and a precursor for polyamines and nitric oxide, and is essential for placentation, angiogenesis, and growth. Maternal plasma arginine concentrations are found to be lower in pregnancies complicated by fetal growth restriction, and arginine supplementation in later pregnancy is reported to increase birth weight. We measured arginine and the metabolites asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) in the amniotic fluid obtained in pregnancy weeks 13 to 15 from 363 pregnancies with a documented normal outcome and related the concentrations to birth weight, length, and head circumference. Arginine was higher in the amniotic fluid from female (mean 40.8 (SD 10.6) µmol/L) compared to male fetuses (37.4 (SD 11.2) µmol/L, p = 0.003). Despite the gender difference, arginine in the amniotic fluid from gestational weeks 13–15 was the strongest predictor for birth weight, length, and head circumference. ADMA was a strong predictor for birth weight and length, SDMA for birth weight, while Arg/ADMA and Arg/SDMA only predicted head circumference in multiple linear regression models. Due to increased arginine demands, pregnancy is considered a state of relative arginine deficiency. Our findings reflect the importance of a good maternal arginine status in early pregnancy, an observation that should be evaluated in an intervention study.

Ablation of Arginase II Spares Arginine and Abolishes the Arginine Requirement for Growth in Male Mice

BackgroundArginine is considered a semiessential amino acid in many species, including humans, because under certain conditions its demand exceeds endogenous production. Arginine availability, however, is determined not only by its production but also by its disposal. Manipulation of disposal pathways has the potential to increase availability and thus abolish the requirement for arginine. ObjectiveThe objective of the study was to test the hypothesis that arginase II ablation increases arginine availability for growth. MethodsIn a completely randomized design with a factorial arrangement of treatments, postweaning growth was determined for 3 wk in male and female wild-type (WT) mice and arginase II knockout mice (ARGII) on a C57BL/6J background fed arginine-sufficient [Arg(+); 8 g arginine/kg] or arginine-free [Arg(−)] diets. Tracers were used to determine citrulline and arginine kinetics. ResultsA sex dimorphism in arginine metabolism was detected; female mice had a greater citrulline flux (∼30%, P < 0.001), which translated to greater de novo synthesis of arginine (∼31%, P < 0.001). Female mice also had greater arginine fluxes (P < 0.015) and plasma arginine concentrations (P < 0.01), but a reduced arginine clearance rate (P < 0.001). Ablation of arginase II increased plasma arginine concentrations in both sexes (∼27%, P < 0.01) but increased arginine flux only in males (P < 0.01). The absence of arginine in the diet limited the growth of male WT mice (P < 0.01), but had no effect on male ARGII mice (P = 0.12). In contrast, WT females on the Arg(−) diet grew at the same rate and achieved final weight similar to that of female WT mice fed the Arg(+) diet (P = 0.47). ConclusionThe ablation of arginase II in male mice spares arginine that can then be used for growth and to meet other metabolic functions, thus abolishing arginine requirements.

561 Effects of ractopamine hydrochloride on lysine utilization by growing cattle

Two separate sets of 6 ruminally cannulated Holstein steers (240 kg) were used to study effects of ractopamine on lysine utilization. Steers were housed in metabolism crates and limit-fed 2.52 kg DM/d of a diet (10.1% CP) containing 82% soybean hulls twice daily. Treatments were arranged as a 2 × 3 factorial with 2 levels of ractopamine-HCl (0 and 200 mg/d) and 3 levels of lysine (0, 6, and 15 g/d) continuously infused abomasally. For each replicate of 6 steers, a completely randomized design was used for main-plot treatments (ractopamine-HCl; 0 vs 200 mg/d). Each steer received subplot treatments (lysine; 0, 6, or 15 g/d) in random sequence, such that each replicate contained concurrent 3 × 3 Latin squares, with each Latin square representing either 0 or 200 mg/d ractopamine-HCl. All steers were continuously infused ruminally with 200 g/d acetic acid, 200 g/d propionic acid, and 50 g/d butyric acid and abomasally with 300 g/d glucose to increase energy supply. Urea (10 g/d) was infused ruminally to ensure adequate ruminal ammonia. Steers were abomasally infused with excess of all essential AA except lysine to ensure lysine was solely limiting. Periods were 6 d with N retention measured on d 3 to 6 and longissimus biopsies and blood collected on d 6. Lysine increased (P<0.01) N retention for both control steers (21.3, 28.6, 33.9 g/d) and ractopamine-fed steers (25.5, 33.2, 38.9 g/d); ractopamine tended (P= 0.07) to increase N retention. Lysine linearly decreased (P<0.01) plasma urea (2.83, 2.04, 1.88 mM), leucine, and valine, but increased (P<0.01) plasma lysine (34, 51, 76 mM), arginine, and alanine. Ractopamine decreased (P<0.05) plasma lysine and arginine concentrations. In longissimus, ractopamine increased (P<0.05) phosphorylation of RPS6 on Ser-235 and Ser-244, and tended to increase (P= 0.08) phosphorylation of AKT on Thr-308 but not Ser-473. Abundance of MAFbx was decreased (P= 0.01) and MURF1 was numerically decreased (P= 0.14) by ractopamine. Lysine supplementation did not affect phosphorylation of RPS6 or AKT or abundance of MAFbx or MURF1. The efficiency of lysine use between 0 and 6 g/d supplemental lysine was 49% for control and 51% for ractopamine-supplemented steers. N retention tended to be improved by ractopamine when lysine supply was limiting, but incremental efficiencies of lysine utilization were not affected by ractopamine, suggesting that ractopamine reduced maintenance requirements for lysine.

Do anabolic nutritional supplements stimulate human growth hormone secretion in elderly women with heart failure?

Growth hormone treatment has gained attention over the past decade as a treatment for heart failure. Human growth hormone (HGH) must be administered by injections (usually daily), so there is considerable advantage to stimulation of endogenous secretion by amino acid‐based nutritional supplementation. However, studies investigating the effect of amino acid (AA) supplementation show conflicting results. Therefore, in this study we aimed to investigate the effect of nutritional supplementation on HGH production in elderly women with heart failure. Eight elderly women with heart failure participated in this randomized cross‐over study. Plasma HGH concentration was measured before and for 4 h following ingestion of a mixture of protein, carbohydrate, and fat or an AA beverage. HGH concentration was determined with ELISA kits and AA concentrations were analyzed by Liquid Chromatography–Mass Spectrometry (LCMS). Linear mixed models was performed to analyze the effect of time, treatment, and interaction. Plasma arginine and lysine concentrations were significantly higher after consumption of the AA drink compared to the mixture of protein, carbohydrate, and fat. Nonetheless, only ingestion of the protein, carbohydrate, and fat mixture (meal replacement) increased HGH concentration. HGH concentration was increased in elderly women with heart failure following consumption of a meal replacement containing protein, carbohydrate, and fat. Consumption of a mixture of amino acids failed to increase HGH concentration despite significantly greater elevations in plasma amino acid concentrations, including arginine and lysine. The stimulatory effect of the protein/carbohydrate/fat mixture was presumably mediated by factors other than increases in free amino acid concentrations.

Expansion study of ADI-PEG 20, pemetrexed and cisplatin in patients with ASS1-deficient malignant pleural mesothelioma (TRAP).

8553 Background: Argininosuccinate synthetase 1 (ASS1)-deficient malignant pleural mesothelioma (MPM) cells are sensitive to arginine deprivation with pegylated arginine deiminase (ADI-PEG20), which also potentiates the cytotoxic effect of pemetrexed (PEM). In the phase I dose-escalation TRAP study (NCT02029690) we showed that ADI-PEG20 with first-line PEM and cisplatin (CIS) chemotherapy (ADIPEMCIS) produced a 100% disease control rate (DCR) in patients (pts; n = 9) with ASS1-deficient thoracic cancers, with no additional toxicity (Beddowes et al 2017). Here, we present the TRAP expansion cohort experience in MPM. Methods: Good performance (ECOG 0-1) MPM pts with non-resectable disease and measurable by modified RECIST, were enrolled in a phase I TRAP expansion cohort at the maximum tolerated dose (MTD) of ADIPEMCIS, using tumoral ASS1 loss as a selection biomarker. PEM (500mg/m2) and CIS (75mg/m2) were given every 3 weeks with weekly IM ADI-PEG20 (36mg/m2) for a maximum of 6 cycles with maintenance ADI-PEG20 in responding pts. Primary endpoint was tumor response rate (modified RECIST), with secondary endpoints including progression-free survival (PFS), overall survival (OS), and toxicity. We measured plasma arginine and citrulline concentrations, ADI-PEG20 antibodies, and biopsied patients on progression to explore resistance mechanisms. Results: 31 ASS1-deficient MPM pts (median age 67) were enrolled (11 epithelioid, 10 biphasic and 10 sarcomatoid) out of 92 screened pts. Plasma arginine decreased with a reciprocal increase in plasma citrulline. The partial response rate was 35.5% (95% CI 19.2%-54.6%) with a DCR of 93.5% (95% CI 78.6%-99.2%). Median PFS was 5.6 months (95% CI 4-6) and median OS was 10.1 months (95% CI 6.7-17.7). 10/31 pts (32.3%) experienced grade 3/4 treatment-related toxicities, the most common being neutropenia (16.1%). Upregulation of ASS1 expression was observed in 2/3 biopsies on progression. Conclusions: The ADIPEMCIS regimen is active in ASS1-deficient MPM pts, including non-epithelioid disease. Based on these data the ATOMIC-meso phase 2/3 trial has opened comparing ADIPEMCIS versus PEMCISPlacebo, focusing on pts with non-epithelioid MPM. Clinical trial information: NCT02029690.

Arginine supplementation for prevention of necrotising enterocolitis in preterm infants.

Decreased concentration of nitric oxide has been proposed as one of the possible cellular mechanisms of necrotising enterocolitis (NEC). Arginine can act as a substrate for production of nitric oxide in the tissues, and arginine supplementation may help to prevent NEC. To examine the effect of arginine supplementation (administered by any route) on the incidence of NEC in preterm neonates. To conduct subgroup analyses based on the dose of arginine and the gestational age of participants (≤ 32 weeks, > 32 weeks). We used the standard search strategy of the Cochrane Neonatal Review Group to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 4), MEDLINE via PubMed (from 1966 to 12 May 2016), Embase (from 1980 to 12 May 2016) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; from 1982 to 12 May 2016). We also searched clinical trials databases, conference proceedings and reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. Randomised and quasi-randomised controlled trials of arginine supplementation (administered orally or parenterally for at least seven days, in addition to what an infant may be receiving from an enteral or parenteral source) compared with placebo or no treatment. We assessed the methodological quality of trials by using information obtained from study reports and through personal communication with study authors. We extracted data on relevant outcomes and estimated and reported the effect size as risk ratio (RR), risk difference (RD) and mean difference (MD), as appropriate. We used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess the quality of evidence. We identified three eligible studies that included a total of 285 neonates (140 received arginine) from three countries. We assessed the overall methodological quality of the included studies as good. We noted a statistically significant reduction in risk of development of NEC (any stage) among preterm neonates in the arginine group compared with the placebo group (RR 0.38, 95% confidence interval (CI) 0.23 to 0.64; I2 = 27%) (RD -0.19, 95% CI -0.28 to -0.10; I2 = 0%) and rated the quality of evidence as moderate. The number needed to treat for an additional beneficial outcome (NNTB) as required to prevent the development of NEC (any stage) was 6 (95% CI 4 to 10). Study results showed a statistically significant reduction in risk of development of NEC stage 1 (RR 0.37, 95% CI 0.15 to 0.90; I2 = 52%) (RD -0.07, 95% CI -0.14 to -0.01; I2 = 0%) and NEC stage 3 (RR 0.13, 95% CI 0.02 to 1.03; I2 = 0%) (RD -0.05, 95% CI -0.09 to -0.01; I2 = 89%) in the arginine group compared with the control group; the quality of evidence was moderate.Arginine supplementation was associated with a significant reduction in death related to NEC (RR 0.18, 95% CI 0.03 to 1.00; I2 = 0%) (RD -0.05, 95% CI -0.09 to -0.01; I2 = 87%). Results showed clinical heterogeneity in mortality rates. Mortality due to any cause was not significantly different between arginine and control or no treatment groups (RR 0.77, 95% CI 0.41 to 1.45; I2 = 42%) (RD -0.03, 95% CI -0.10 to 0.04; I2 = 79%). Investigators noted no significant side effects directly attributable to arginine, including hypotension or alterations in glucose homeostasis. Follow-up data from one trial revealed no statistically significant differences in adverse outcomes (cerebral palsy, cognitive delay, bilateral blindness or hearing loss requiring hearing aids) at 36 months. Limitations of the present findings include a relatively small overall sample size. Administration of arginine to preterm infants may prevent development of NEC. Because information was provided by three small trials that included 285 participants, the data are insufficient at present to support a practice recommendation. A multi-centre randomised controlled study that is focused on the incidence of NEC, particularly at more severe stages (2 and 3), is needed.

Metabolomic profiling in patients undergoing Off-Pump or On-Pump coronary artery bypass surgery

BackgroundCoronary artery bypass surgery can be performed without (Off-Pump) or with cardiopulmonary bypass (On-Pump). Extracorporeal circulation and cardioplegic arrest may cause alterations in the plasma metabolome. We assessed metabolomic changes in patients undergoing On-Pump or Off-Pump coronary artery bypass surgery.MethodsWe assessed five analyte classes (41 acylcarnitines, 14 amino acids, 92 glycerophospholipids, 15 sphingolipids, sugars, lactate) using a mass-spectrometry-based kit (Biocrates AbsoluteIDQ® p150) in paired arterial and coronary sinus blood obtained from 10 consecutive On-Pump and 10 Off-Pump patients. Cardioplegia for On-Pump was warm blood Calafiore. On-Pump outcomes were corrected for hemodilution through crystalloid priming.ResultsDemographic data were equal in both groups with normal ejection fraction, renal and liver function. Patients received 2.25 ± 0.64 bypass grafts. All postoperative courses were uneventful. Of 164 measured metabolites, only 13 (7.9%) were altered by cardiopulmonary bypass. We found more long-chain acylcarnitines Off-Pump and more short-chain acylcarnitines On-Pump. Glycerophospholipids showed lower concentrations On-Pump and arginine (as the only different amino acid) Off-Pump. Interestingly, plasma arginine (nitric oxide precursor) concentration at the end of surgery correlated inversely with postoperative vasopressor need (r = −0.7; p < 0.001). Assessing arterial/venous differences revealed phosphatidylcholine-production and acylcarnitine-consumption. These findings were unaffected by cardiopulmonary bypass, cardioplegia or temporary vessel occlusion during Off-Pump surgery.ConclusionsCardiopulmonary bypass and warm blood cardioplegia cause only minor changes to the metabolomic profile of patients undergoing coronary artery bypass surgery. The observed changes affected mainly acylcarnitines. In addition, there appears to be a relationship between arginine and vasopressor need after bypass surgery.

Dietary glutamine supplementation enhances expression of ZO-1 and occludin and promotes intestinal development in Min piglets

ABSTRACTForty-eight Min piglets at 7 days of age were randomly divided into two groups which were fed with 0% and 0.8% glutamine, respectively. Supplementation with 0.8% l-glutamine, the average daily gain (ADG) were significantly increased, and the concentrations of glutamine, glutamate, arginine and citrulline in plasma were significantly improved (P < .05). The expression of jejunal mucosa glutathione peroxidase (GSH-Px) and total superoxide dismutase (T-SOD) were both significantly increased, and the concentration of malonaldehyde (MDA) was significantly reduced (P < .05). Furthermore, the villus height and the villus height to crypt depth ratio were significantly increased (P < .05). Glutamine supplementation significantly increased the expression levels of occludin mRNA and protein (P < .05), while the mRNA and protein expression levels of ZO-1 were not significantly affected. These results showed that dietary supplementation with glutamine contributed to improving intestinal development and whole-body growth in Min piglets.

Relationships between plasma amino acid concentrations and blood pressure in South Africans of African descent

Oral supplementation with the amino acid arginine, the precursor of the vasodilator nitric oxide (NO), is associated with a reduction in blood pressure (BP). However, it is uncertain whether a decreased plasma arginine concentration predicts increases in BP. We assessed the relationship between fasting plasma arginine or other amino acid concentrations and 24 hour ambulatory BP in 75 nevertreated participants recruited from the Johannesburg area, 55 of whom were male. Plasma amino acid concentrations were measured with high performance liquid chromatography-mass-spectrometry. Plasma arginine concentrations were not inversely correlated with ambulatory BP. However, plasma arginine concentrations were increased in 36 participants with a mean daytime systolic BP &gt;140 mm Hg (61 ± 17 μmol/L) as compared to the remaining participants (54 ± 15 μmol/L, p‹0.05). Moreover, plasma arginine concentrations were positively correlated with 24-hour diastolic BP (r=0.26, p‹0.05). In males with a BMI‹30kg/m2, plasma arginine concentrations were positively correlated with both night diastolic (r=0.46, p‹0.005) and systolic (r=0.42, p‹0.005) BP. In a multivariate model with adjustments for age gender, body mass index, and other amino acid concentrations, plasma arginine concentrations were independently and positively associated with night diastolic BP (p‹0.05). In conclusion plasma arginine concentrations are positively associated with ambulatory BP in a group of participants of African descent in South Africa. These data do not support the notion that deficiencies of arginine, the amino acid substrate for NO, are related to increases in BP in groups of African ancestry living in South Africa. However, as with other ethnic groups, the positive relationship between plasma arginine concentrations and BP suggests a reduced capacity to utilise the amino acid substrate for NO synthesis.

Supplemental Citrulline Is More Efficient Than Arginine in Increasing Systemic Arginine Availability in Mice

BackgroundArginine is considered to be an essential amino acid in various (patho)physiologic conditions of high demand. However, dietary arginine supplementation suffers from various drawbacks, including extensive first-pass extraction. Citrulline supplementation may be a better alternative than arginine, because its only fate in vivo is conversion into arginine. ObjectiveThe goal of the present research was to determine the relative efficiency of arginine and citrulline supplementation to improve arginine availability. MethodsSix-week-old C57BL/6J male mice fitted with gastric catheters were adapted to 1 of 7 experimental diets for 2 wk. The basal diet contained 2.5 g L-arginine/kg, whereas the supplemented diets contained an additional 2.5, 7.5, and 12.5 g/kg diet of either L-arginine or L-citrulline. On the final day, after a 3-h food deprivation, mice were continuously infused intragastrically with an elemental diet similar to the dietary treatment, along with L-[13C6]arginine, to determine the splanchnic first-pass metabolism (FPM) of arginine. In addition, tracers were continuously infused intravenously to determine the fluxes and interconversions between citrulline and arginine. Linear regression slopes were compared to determine the relative efficiency of each supplement. ResultsWhereas all the supplemented citrulline (105% ± 7% SEM) appeared in plasma and resulted in a marginal increase of 86% in arginine flux, supplemental arginine underwent an ∼70% FPM, indicating that only 30% of the supplemental arginine entered the peripheral circulation. However, supplemental arginine did not increase arginine flux. Both supplements linearly increased (P < 0.01) plasma arginine concentration from 109 μmol/L for the basal diet to 159 and 214 μmol/L for the highest arginine and citrulline supplementation levels, respectively. However, supplemental citrulline increased arginine concentrations to a greater extent (35%, P < 0.01). ConclusionsCitrulline supplementation is more efficient at increasing arginine availability than is arginine supplementation itself in mice.

Amino acid profiling in the gestational diabetes mellitus

BackgroundThe prevalence of gestational diabetes mellitus (GDM) is increasing globally which is associated with various side effects for mothers and fetus. It seems that metabolomic profiling of the amino acids may be useful in early diagnosis of metabolic diseases. This study aimed to explore the association of the amino acids profiles with GDM.MethodsEighty three pregnant women with gestational age ≥25 weeks were randomly selected among pregnant women referred to prenatal care clinic in Arash hospital of Tehran, Iran. Women divided into three groups including 1) 25 pregnant women with normal glucose tolerance test, 2) 27 pregnant women with diabetes type 2 (T2D) (n: 27) and 3) 31 women with GDM (n: 31). Plasma levels of amino acids were measured by high performance liquid chromatography and were compared in three groups. Statistical analysis was performed using SPSS 16.ResultsCompared with normal mothers, GDM mothers showed higher plasma concentrations of Arginine (P = 0.01), Glycine (P = 0.01) and Methionine (P = 0.04), whereas the pregnant women with T2D had higher plasma levels of Asparagine (P = 0.01), Tyrosine (P < 0.01), Valine (P < 0.01), Phenylalanine (P < 0.01), Glutamine (P < 0.01) and Isolucine (P < 0.01). The results of regression analyses confirmed the significantly elevated in plasma concentration of Asparagine (OR:3.64, CI 1.22–10.47), Threonine (OR:3.38, CI 1.39–8.25), Aspartic acid (OR:3.92, CI 1.19–12.91), Phenylalanine (OR:2.66, CI 1.01–6.94), Glutamine (OR:2.53, CI 1.02–6.26) and Arginine (OR:1.96, CI 1.02–3.76) after adjustment for gestational age and BMI in GDM mothers compared to normal ones.ConclusionsAmino acids levels are associated with risk of GDM and diabetes mellitus. However further prospective studies are needed to clarify the role of different metabolites involved in mechanism of GDM.

Micronutrients, Essential Fatty Acids and Bone Health in Phenylketonuria

Introduction: In phenylketonuria (PKU), a natural protein-restricted dietary treatment prevents severe cognitive impairment. Nutrient deficiencies may occur due to strict diet. This study is aimed at evaluating the dietary intake and blood concentrations of micronutrients and essential fatty acids (FA), bone mineral density (BMD) and fracture history in patients on long-term dietary treatment. Methods: Sixty early diagnosed Dutch patients (aged 1-39 years) were included in a multi-center cross-sectional study. Their dietary intake, blood concentrations of micronutrients, FA, fracture history and BMD were assessed. Results: Selenium dietary intake and serum concentrations were low in 14 and 46% of patients, respectively. The serum 25-OH vitamin D2 + D3 concentration was low in 14% of patients while 20% of patients had a low vitamin D intake. Zinc serum concentrations were below normal in 14% of patients, despite adequate intake. Folic acid serum concentrations and intake were elevated. Despite safe total protein and fat intake, arginine plasma concentrations and erythrocyte eicosapentaenoic acid were below reference values in 19 and 6% of patients, respectively. Low BMD (Z-score <-2) was slightly more prevalent in patients, but the lifetime fracture prevalence was comparable to the general population. Conclusions: Dutch patients with PKU on long-term dietary treatment have a near normal nutrient status. Supplementation of micronutrients of which deficiency may be deleterious (e.g., vitamin D and selenium) should be considered. BMD warrants further investigation.