Plasma Citrulline Concentrations Research Articles

Clinical and genetic analysis of 26 Chinese patients with neonatal intrahepatic cholestasis due to citrin deficiency

BackgroundNeonatal intrahepatic cholestasis due to citrin deficiency (NICCD) is an autosomal recessive disorder caused by SLC25A13 genetic mutations. We retrospectively analyzed 26 Chinese infants with NICCD (years 2014-2022) in Quanzhou City. MethodsThe plasma citrulline (CIT) concentration analyzed by tandem mass spectrometry (MS/MS), biochemical parameters and molecular analysis results are presented. ResultsTwelve genotypes were discovered. The relationship between the CIT concentration and genotype is uncertain. In total, 8 mutations were detected, with 4 variations, c.851_854delGTAT, c.615 + 5G > A, c.1638_1660dup and IVS16ins3kb, constituting the high-frequency mutations. Specifically, we demonstrated 2 patients with NICCD combined with another inborn errors of metabolism (IEM). Patient No. 22 possessed compound heterozygous mutations of c.615 + 5G > A and c.790G > A in the SLC25A13 gene accompanied by compound heterozygous variations of c.C259T and c.A155G in the PTS gene. Additionally, Patient No. 26 carried c.51C > G and c.760C > T in the SLC22A5 gene as well as c.615 + 5G > A and IVS16ins3kb in the SLC25A13 gene. ConclusionsWe report a case of the simultaneous occurrence of primary carnitine deficiency (PCD) and NICCD.

Plasma citrulline concentration and plasma LPS detection among critically ill patients a prospective observational study

PurposeGut can be a source of sepsis but sepsis itself can induce gut dysfunction. We aimed to study whether plasma citrulline, a marker of enterocyte mass, was correlated with plasma lipopolysaccharide, a potential marker of bacterial translocation among critically ill patients. Materials and methodsCritically ill patients admitted to the ICU. Plasma citrulline and plasma LPS concentration and activity were measured at ICU admission. Patients were compared according to the presence of sepsis at ICU admission. Results109 critically ill patients, with SOFA score 8 [6–12], were prospectively included. Sixty six patients (61%) had sepsis at ICU admission. There was no correlation between plasma citrulline concentration and plasma LPS concentration or activity. However, sepsis at ICU admission was associated with a lower plasma citrulline concentration (13.4 μmol.L−1 vs 21.3 μmol.L−1, p = 0.02). Plasma LPS activity was significantly higher among patients with abdominal sepsis compared to patients with extra-abdominal sepsis (1.04 EU/mL vs 0.63, p = 0.01). ConclusionsPlasma citrulline is not associated with the level of plasma LPS but is strongly decreased among septic patients. Detection of LPS is ubiquitous among critically ill patients but abdominal sepsis is associated with increased plasma LPS activity compared to extra-abdominal sepsis.

Protective effects and mechanisms of N-acetylcysteine on indomethacin-induced intestinal injury in a porcine model

This study aimed to investigate the effect of N-acetylcysteine (NAC) on indomethacin (IDMT)-induced intestinal injury in a piglet model and explore the underlying molecular mechanisms. Piglets were randomly divided into 3 treatment groups: (1) control group; (2) IDMT group; (3) NAC+IDMT group. The results showed that NAC administration significantly increased the average daily gain of piglets, attenuated the intestine hyperemia, and restored normal jejunal morphology. Further studies indicated that NAC administration significantly increased plasma citrulline concentration and jejunal villin expression, but decreased the content of proinflammatory cytokines in plasma and jejunum of IDMT-stimulated piglets. NAC administration selectively decreased the proportion of eosinophils but not neutrophils in plasma. Furthermore, NAC administration significantly increased the activities of superoxide dismutase and catalase in plasma but decreased the concentrations of hydrogen peroxide (plasma) and malondialdehyde (plasma and jejunum), as well as the activity of myeloperoxidase (jejunum) when comparing NAC+IDMT group with IDMT group. Gene Ontology analysis showed that the significantly enriched molecular function term was “ubiquitin-like protein ligase binding” for NAC+IDMT versus IDMT differentially regulated genes. In the biological process category, differentially regulated genes of NAC+IDMT versus IDMT were mainly enriched in immune-related terms. The major enrichments for differentially regulated proteins (DRPs) of NAC+IDMT versus IDMT were terms involved in lipid metabolism and immune response. KEGG pathway enrichment analysis showed that “arginine biosynthesis” was a significant enrichment term for the DRPs of NAC+IDMT versus IDMT. Further studies demonstrated that NAC administration up-regulated argininosuccinate synthase 1 mRNA expression and down-regulated arginase mRNA expression in the jejunum of IDMT-stimulated piglets. Moreover, the content of nitric oxide was restored to a normal level with the reduction of nitric oxide synthase activity. NAC administration ameliorated intestinal injury in IDMT-challenged piglets by enhancing antioxidant and anti-inflammatory functions and modulating arginine metabolism in the small intestine.

Arginine Dysregulation and Myocardial Dysfunction in a Mouse Model and Children with Chronic Kidney Disease

Cardiovascular disease is the leading cause of death in chronic kidney disease (CKD). Arginine, the endogenous precursor for nitric oxide synthesis, is produced in the kidneys. Arginine bioavailability contributes to endothelial and myocardial dysfunction in CKD. Plasma from 129X1/SvJ mice with and without CKD (5/6th nephrectomy), and banked plasma from children with and without CKD were analyzed for amino acids involved in arginine metabolism, ADMA, and arginase activity. Echocardiographic measures of myocardial function were compared with plasma analytes. In a separate experiment, a non-specific arginase inhibitor was administered to mice with and without CKD. Plasma citrulline and glutamine concentrations correlated with multiple measures of myocardial dysfunction. Plasma arginase activity was significantly increased in CKD mice at 16 weeks vs. 8 weeks (p = 0.002) and ventricular strain improved after arginase inhibition in mice with CKD (p = 0.03). In children on dialysis, arginase activity was significantly increased vs. healthy controls (p = 0.04). Increasing ADMA correlated with increasing RWT in children with CKD (r = 0.54; p = 0.003). In a mouse model, and children, with CKD, arginine dysregulation correlates with myocardial dysfunction.

Metabolic effects of glutamine and glutamate ingestion in healthy subjects and in persons with chronic obstructive pulmonary disease

Because low plasma glutamate and glutamine concentrations are often seen in chronic obstructive pulmonary disease (COPD), glutamine or glutamate supplementation may be a good option for preventing further metabolic disturbances in COPD patients. However, the metabolic effects of glutamate supplementation have never been compared with those of glutamine supplementation. We compared the metabolic effects of repeated ingestion of glutamine and glutamate in COPD patients and in age-matched healthy control subjects. On 3 d separated by intervals of > or = 2 d, a protocol of primed constant and continuous infusion of [2H5]phenylalanine and [2H2]tyrosine was performed for 3 h in 8 stable male COPD patients and 8 healthy control subjects. After a 90-min tracer infusion, all subjects ingested a glutamine or glutamate drink or the same amount of water every 20 min for 80 min. Blood samples were taken at the end of the postabsorptive and ingestion periods to test for effects on plasma amino acid and substrate concentrations and whole-body protein turnover. Glutamate but not glutamine ingestion resulted in higher plasma ornithine concentrations than did water ingestion (P < 0.01). The change in plasma arginine, citrulline, and urea concentrations was significantly (P < 0.01) higher after glutamine ingestion than after water or glutamate ingestion. Whole-body protein turnover decreased overall, independent of the drink consumed. Repeated ingestion of glutamine and glutamate resulted in different effects on the plasma amino acid concentration. In both groups, ingestion of glutamine but not of glutamate increased the plasma concentrations of citrulline and arginine, substrates produced in the intestine and the liver.

Net Renal Arginine Flux in Rats is Not Affected by Dietary Arginine or Dietary Protein Intake

Kidneys of adult animals serve as a major biosynthetic source of arginine. Recently, we demonstrated that kidneys of rats infused with citrulline responded to the elevated plasma citrulline concentrations by increasing citrulline uptake and producing greater quantities of arginine. The objective of the present study was to determine the effects of feeding adult male rats different levels of arginine or protein on renal arginine synthesis. Feeding arginine (0, 0.5 and 2.0%) for 1 wk increased circulating plasma concentrations of arginine 2.5-fold (196 mumol/L) in the 2.0% arginine group compared with the 0 and 0.5% arginine groups (73 and 81 mumol/L, respectively). However, the plasma citrulline concentration was unchanged. The renal uptake of citrulline and release of arginine were similar in all the three groups fed different levels of arginine. Feeding diets containing 5, 12 and 50% protein for 1 wk did not alter the circulating plasma concentrations of either citrulline or arginine, and there were no significant differences in the renal release of arginine. These results suggest that renal arginine synthesis is independent of dietary arginine or protein intake.

Different dietary starch patterns in low-protein diets: effect on nitrogen efficiency, nutrient metabolism, and intestinal flora in growing pigs

BackgroundProtein releases amino acids faster than starch releases glucose in digestive tract of pigs fed low-protein (LP) diets. Poor synchronization of dietary glucose and amino acids supply leads to compromised nitrogen efficiency. Dietary starch patterns modulation may improve this situation.MethodsGrowing barrows (29.7 ± 2.0 kg) were randomly allotted into 5 dietary treatments with LP diets consisting of different purified starches. Treatments included: waxy corn starch (W LP), corn starch + waxy corn starch (C + W LP), corn starch (C LP), pea starch + waxy corn starch (P + W LP) and pea starch (P LP). In the experiment, growth performance, protein deposition, nutrient metabolism, and fecal microbial community of pigs were investigated. In vitro starch digestion was used for predicting the in vivo glucose response.ResultsDietary starch in vitro glucose release profile was determined by starch source and the ratio of amylopectin and amylose. C + W LP treatment showed decreased total nitrogen excretion and plasma citrulline concentration and improved plasma leptin concentration among treatments (P < 0.05). Besides, the highest nitrogen apparent biological value, whole-body protein deposition and growth performance and lowest urinary nitrogen excretion were also observed in C + W LP treatment. Compared with the other groups, C + W LP and C LP showed increased plasma pyruvate, IGF-1, and lipase concentrations (P < 0.05). The W LP group presented dramatically increased plasma alanine and urea nitrogen concentration and decreased aldolase and leptin concentrations (P < 0.05). Dietary starch patterns did not make an impact on bacterial richness and diversity, but changed the taxonomic and functional structures of the microbial communities. Microbial protein fermentation product (isobutyrate and isovalerate) presented increased in P LP treatments compared with the other treatments (P < 0.05).ConclusionsDietary starch patterns modulation can regulate dietary glucose release profile, nutrient metabolism, protein turnover, and fecal microbial fermentation in pigs. The optimal dietary glucose release profile effectively strengthened whole-body protein deposition and improve nitrogen efficiency and growth performance in growing pigs fed LP diets.

Maternal oral supplementation with citrulline increases plasma citrulline but not arginine in pregnant Merino ewes and neonatal lambs

Context Arginine supplementation can counter the negative effects of fetal growth restriction in ewes bearing multiple lambs by increasing birth weight and brown adipose fat stores in lambs; however ruminal degradation limits its bioavailability and necessitates ruminal protection. The arginine precursor citrulline increases circulating arginine after a single oral dose without ruminal protection, and bolus intravenous infusion of citrulline increases maternal and fetal circulating arginine for at least 4 h post infusion. Responses to oral and chronic citrulline have not, however, been evaluated in neonatal lambs. Aims This experiment sought to determine whether orally fed citrulline would increase circulating plasma concentrations of citrulline and arginine in pregnant Merino ewes. Methods Pregnant Merino ewes were fed citrulline (CIT, 8 g/day, n = 9) or no supplement (CON, n = 9) from Day 125 of gestation (DG 125) until parturition. Ewe (DG 125) and neonatal lamb serum (&lt;2 h old) was analysed for circulating plasma citrulline and arginine concentrations. Key results Circulating concentrations of citrulline were higher in CIT than CON ewes 4 h post feeding at DG 125, and in CIT compared to CON neonatal lambs. Despite higher citrulline concentrations, supplementation did not increase maternal or neonatal circulating arginine concentrations. Conclusions Maternal supplementation with this dose of citrulline was not effective in increasing circulating levels of arginine. Implications Further studies may be merited in pregnant sheep to determine whether higher doses of oral citrulline can increase arginine availability during gestation.

Plasma homoarginine concentrations in ewe's pregnancy and association with the number of fetuses

A striking increase in homoarginine concentrations, about more than 100-fold that observed in humans, was recently reported during pregnancy in a nutritionally induced model of intra-uterine growth restriction in ewes. To determine whether this phenomenon is at least partially related to the nutritional regimen, estrus synchronization, or analytical method, thirty-four one-year-old primiparous, non-synchronized, and well-fed Sarda breed ewes were exposed to fertile rams allowing those who came into estrus to naturally mate. Plasma arginine, homoarginine, asymmetric dimethylarginine, symmetric dimethylarginine, mono methylarginine, and citrulline concentrations were measured in each sample using LC-MS/MS. Homoarginine concentrations showed a 44-fold variation between the highest and the lowest values while the fluctuations of arginine and its analogues and metabolites were much smaller, between 1.1 and 1.6-fold. Repeated-measures correlation analysis showed a significant negative correlation between homoarginine/arginine and arginine/asymmetric dimethylarginine ratios (Rm = −0.40; P < 0.000001). Furthermore, median homoarginine concentrations significantly increased with the number of fetuses. The marked increase in homoarginine concentrations with advancing gestational age is genuine and independent of mating, feeding, diet, and hormone treatment. The higher homoarginine concentrations found in ewes bearing multiple fetuses suggest the presence of a physiological link between this arginine analog and energy metabolism in pregnancy that warrants further investigation.

Efficacy of peritoneal dialysis on encephalopathic patient with Citrullinemia type I

Abstract Citrullinemia type I (CTLN1) clinical spectrum includes an acute neonatal form ("classic" form) and a milder late-onset form (“non-classic" form). Infants with classic form appear normal at birth. Shortly thereafter, they experienced hyperammonemia and develops symptoms. Without prompt intervention, rapid neurological deterioration with seizures, spasticity, loss of consciousness and even death can occur. Continuous venovenous hemofiltration should be started in neonates and children with ammonia levels &amp;gt; 500 µmol/L or even at lower levels if there has been an inadequate response to medical management after 4 hours. Alternatively, but only in centers that lack ability or expertise to perform extracorporeal therapy, peritoneal dialysis can be utilized. The hallmarks of dialysis is rapid lowering of plasma ammonia concentration to avoid neurotoxicity and irreversible brain damage. Objectives To evaluate the effect of peritoneal dialysis on plasma ammonia levels and the clinical outcome in an encephalopathic Egyptian patient with CTLN1. Patient and Methods A 2.5 year old male patient with a classical form of CTLN1was recruited. The first presenting symptom of the patient was poor suckling and disturbed conscious level at the age of 5 day. He was admitted to neonatal intensive-care unit (NICU) with hyperammonemic encephalopathy and abnormal pattern of breathing. He developed apneic attack and underwent mechanical ventilation. The diagnosis of CTLN1 was established with elevated plasma ammonia concentration (350 µmol/L) and plasma citrulline concentration (2570 µmol/L). The patient was managed with peritoneal dialysis for 4 days, together with protein restriction, sodium benzoate, arginine therapy and high caloric intake. Results Plasma ammonia level was decreased with improvement of general condition and conscious level after dialysis. Upon discharge from NICU, the patient was referred to our Genetic clinic and no history of further hospital admission since then. Mild developmental delay mainly cognitive was noted during his regular clinic follow up. Conclusion CTLN1 can present with hyperammonemic encephalopathy which could be lethal if not promptly managed. Peritoneal dialysis proved to be an effective therapy of reducing plasma ammonia rapidly and improving outcome of the patient.

Accuracy of citrulline, I-FABP and d-lactate in the diagnosis of acute mesenteric ischemia

Early diagnosis of acute mesenteric ischemia (AMI) remains a clinical challenge, and no biomarker has been consistently validated. We aimed to assess the accuracy of three promising circulating biomarkers for diagnosing AMI—citrulline, intestinal fatty acid-binding protein (I-FABP), and d-lactate. A cross-sectional diagnostic study enrolled AMI patients admitted to the intestinal stroke center and controls with acute abdominal pain of another origin. We included 129 patients—50 AMI and 79 controls. Plasma citrulline concentrations were significantly lower in AMI patients compared to the controls [15.3 μmol/L (12.0–26.0) vs. 23.3 μmol/L (18.3–29.8), p = 0.001]. However, the area under the receiver operating curves (AUROC) for the diagnosis of AMI by Citrulline was low: 0.68 (95% confidence interval = 0.58–0.78). No statistical difference was found in plasma I-FABP and plasma d-lactate concentrations between the AMI and control groups, with an AUROC of 0.44, and 0.40, respectively. In this large cross-sectional study, citrulline, I-FABP, and d-lactate failed to differentiate patients with AMI from patients with acute abdominal pain of another origin. Further research should focus on the discovery of new biomarkers.

Variation of plasma citrulline as a predictive factor for weaning off long-term parenteral nutrition in children with neonatal short bowel syndrome

Long-term parenteral nutrition (PN) is the mainstay of the therapeutic strategy in intestinal failure (IF) due to neonatal short bowel syndrome (SBS). Our aim was to identify prognostic factors for PN weaning and to assess if measuring plasma citrulline concentrations over time could account for the intestinal adaptation in progress. This retrospective study included children with neonatal SBS with surgical measurement of the residual bowel length and repeated plasma citrulline assessments during a 4-year follow-up. The degree of IF was assessed by the PN dependency index (PN caloric intake/Resting energy expenditure). The analysis was carried out according to SBS anatomical groups: end-jejunostomy (type 1), jejuno-colic (type 2) and jejuno-ileal anastomosis (type 3). Fifty-five patients (8 type 1, 27 type 2, 20 type 3) were included. None of the patients with SBS type 1, 11 (41%) with type 2 and 11 (55%) with type 3 were weaned off during the follow-up period. Plasma citrulline levels significantly increased with time in patients who were finally weaned off PN; conversely, the levels did not consistently increase in patients who were still on PN at the end of the study period. There was an inverse relationship between plasma citrulline levels and the PN dependency index. The increasing citrulline levels had a positive effect on the probability of weaning, 2.7 times higher for each point increase in citrulline. No significant effect of age and residual bowel length at baseline was found. The increased plasma citrulline level over time in addition to the SBS anatomical type is a reliable marker for subsequent PN weaning. The prediction of PN weaning assessed solely by the residual bowel length or a single measurement of citrulline is insufficient and should also take into account the anatomical type of SBS and repeated measurements of plasma citrulline levels.

Dietary citrulline does not modify rat colon tumor response to chemotherapy, but failed to improve nutritional status

During cancer therapy many patients experience significant malnutrition, leading to decreased tolerance to chemotherapy and decreased survival. Dietary citrulline supplementation improves nutritional status in situations such as short bowel syndrome and aging, and is of potential interest in oncology. However, a mandatory prerequisite is to test this amino acid for interaction with tumor growth and chemotherapy response. Dietary citrulline (Cit; 2%), or an isonitrogenous mix of non-essential amino acids (control), was given to Ward colon tumor-bearing rats the day before chemotherapy initiation. Chemotherapy included 2 cycles, one week apart, each consisting of one injection of CPT-11 (50mg/kg) and of 5-fluorouracil (50mg/kg) the day after. Body weight, food intake and tumor volume were measured daily. The day after the last injection, rats were killed, muscles (EDL, gastrocnemius), intestinal mucosa, tumor, spleen and liver were weighed. Muscle and intestinal mucosa protein content were measured. Phosphorylated 4E-BP1 was measured in muscle and tumor as a surrogate for biosynthetic activation. FRAPS (Ferric Reducing Ability of Plasma) and thiols in plasma, muscle and tumor were evaluated and plasma amino acids and haptoglobin were measured. Numerous parameters did not differ by diet overall: a) response of tumor mass to treatment, b) tumor antioxidants and phosphorylated 4E-BP1 levels, c) relative body weight and relative food intake, d) weight of EDL, gastrocnemius, intestinal mucosa, spleen and liver and e) plasma haptoglobin concentrations. Moreover, plasma citrulline concentration was not correlated to relative body weight, only cumulated food intake and plasma haptoglobin concentrations were correlated to relative body weight. Citrulline does not alter the tumor response to CPT-11/5FU based therapy but, has no effect on nutritional status, which could be due to the anorexia and the low amount of citrulline and protein ingested.

Outcome of Liver Transplantation for Neonatal-onset Citrullinemia Type I.

We evaluated the outcome of liver transplantation (LT) in neonatal-onset citrullinemia type I patients, especially its impact on neurological deficits and developmental retardation. From October 2006 to October 2019, 5 of the 2003 children who received LT at Ren Ji Hospital had been diagnosed with citrullinemia type I. The primary indication for transplantation was repeated metabolic compensation and developmental retardation in 4 patients and prophylactic transplantation in the other. Among them, 3 patients received living donor LT and 2 received orthotopic LT. All recipients had successfully recovered within the median follow-up period of 32 months (range, 6-54 mo). Transplantation restored citrulline metabolism and liver function. Plasma ammonia and citrulline concentration decreased to normal levels with no further hyperammonemic episodes being reported, even after normal diet intake began. Meanwhile, uracil-2 and orotic acid were not detected in urinary excretion. Strikingly, patients suffered developmental retardation before LT showed improved psychomotor ability and significant catch-up growth during the follow-up period. Cognitive ability, including language skills and academic performance, also greatly improved. Three patients had sustained brain injuries and exhibited severe neurological deficits before transplantation, especially repeated generalized tonic-clonic seizures. LT halted neurological deterioration and controlled seizure episodes, which further facilitated the intellectual development and improvement of life quality. LT is an effective treatment for neonatal-onset citrullinemia type I patients, which reverses metabolism decompensation and improves quality of life. For patients who have suffered severe hyperammonemic insults, LT should be conducted at an early age to avoid further neurological or developmental deficits.

Association of proton pump inhibitor use with endothelial function and metabolites of the nitric oxide pathway: A cross-sectional study.

Long-term intake of proton pump inhibitors (PPIs) might increase the risk of cardiovascular events. One suggested mechanism is that PPIs inhibit the enzyme dimethylarginine dimethylaminohydrolase (DDAH) and thereby block the degradation of endothelial asymmetrical dimethylarginine (ADMA). Excess ADMA in turn leads to impaired endothelial nitric oxide (NO) generation. So far, this mechanism has only been established in human cell cultures. Previous studies that examined this pathway in human populations measured circulating ADMA and found no association with PPI use and excess plasma ADMA. But in a recent study, plasma ADMA was not correlated with intracellular ADMA. We therefore focused on changes in plasma citrulline as an indicator for potential DDAH inhibition. We analyzed the association between regular daily PPI intake and flow-mediated dilation (FMD) of the brachial artery as well as plasma concentrations of citrulline, arginine, ADMA, and symmetric dimethylarginine using inverse probability weighting to adjust for confounding and censoring. Data of 1298 participants from two independent cohorts of the population-based Study of Health in Pomerania were used. Participants of the population-based Study of Health in Pomerania are a stratified random sample of the study region. Regular daily intake of PPIs. FMD of the brachial artery and plasma concentrations of citrulline, arginine, ADMA, and symmetric dimethylarginine. Eighty-seven participants (57.5% female) were regular daily users of PPIs. In the fully adjusted models, associations were identified for FMD and plasma citrulline concentrations. PPI users revealed a 0.99% (95% CI: -1.96 to -0.02) lower FMD and 3.03µmol/L (95% CI: -4.96 to -1.10) lower plasma citrulline levels as compared to non-users. Our data provide evidence that long-term intake of PPIs might inhibit human DDAH activity, resulting in impaired endothelial NO production and reduced vascular function. In the long run, this might explain an increased risk for cardiovascular diseases associated with long-term PPI use.

Pegylated arginine deiminase depletes plasma arginine but maintains tissue arginine availability in young pigs.

Pegylated arginine deiminase (ADI-PEG20) results in the depletion of arginine with the production of isomolar amounts of citrulline. This citrulline has the potential to be utilized by the citrulline recycling pathway regenerating arginine and sustaining tissue arginine availability. The goal of this research was to test the hypothesis that ADI-PEG20 depletes circulating arginine in pigs but maintains tissue arginine concentration and function, and to characterize the kinetics of citrulline and arginine. Two multitracer approaches (bolus dose and primed-continuous infusion) were used to investigate the metabolism of arginine and citrulline in Control (n = 7) and ADI-PEG20 treated (n = 8) pigs during the postprandial period. In addition, blood pressure was monitored by telemetry, and multiple tissues were collected to determine arginine concentration. Plasma arginine was depleted immediately after ADI-PEG20 administration, with an increase in plasma citrulline concentration (P < 0.01). The depletion of arginine did not affect (P > 0.10) blood pressure, whole body protein synthesis, or urea production. Despite the lack of circulating arginine in ADI-PEG20-treated pigs, most tissues were able to maintain concentrations similar (P > 0.10) to those in Control animals. The kinetics of citrulline and arginine indicated the high citrulline turnover and regeneration of arginine through the citrulline recycling pathway. ADI-PEG20 administration resulted in an absolute and almost instantaneous depletion of circulating arginine, thus reducing global availability without affecting cardiovascular parameters and protein metabolism. The citrulline produced from the deimination of arginine was in turn utilized by the citrulline recycling pathway restoring local tissue arginine availability.NEW & NOTEWORTHY Pegylated arginine deiminase depletes circulating arginine, but the citrulline generated is utilized by multiple tissues to regenerate arginine and sustain local arginine availability. Preempting the arginine depletion that occurs as result of sepsis and trauma with arginine deiminase offers the possibility of maintaining tissue arginine availability despite negligible plasma arginine concentrations.

EFFECT OF DOXORUBICIN-INDUCED OXIDATIVE STRESS ON CITRULLINE CONCENTRATION IN THE SMALL INTESTINAL MUCOSA AND PLASMA BLOOD IN RATS WITH NON-ALCOHOLIC STEATOHEPATITIS

The aim: Is to investigate the effect of doxorubicin-induced oxidative stress on plasma citrulline and citrulline concentration in the small intestinal (SI) mucosa of rats with non-alcoholic steatohepatitis (NASH). Materials and methods: The studies were carried out on 30 white non-linear adult rats, 15 (50%) males, 15 (50%) females, weighing 160-220 g. The rats were divided into three groups: І (n=10) – rats without NASH, received a standard diet, subsequently were injected with doxorubicin in cumulative dose of 15 mg/kg; ІI (n=10) – rats with NASH, received a high-calorie diet with doxorubicin injection similarly to group I; ІІІ (n=10) –control group, received a standard diet, were injected with placebo. In the SI mucosa, the levels of thiobarbituric acid reactive substances (TBARS), citrulline and catalase were determined. Also the level of plasma citrulline was analyzed. Results: Doxorubicin injection resulted in induction of oxidative stress in rats of group I and II, which was characterized by 2.1 (p=0.002) and 1.4 times (р=0.0059) increase in TBARS and in 3.4 (р=0.002), and 5.2 times (р=0.002) decrease in catalase activity respectively comparing with the control group. Simultaneously plasma citrulline level in group I and II was in 1.4 (р=0.0039) and 1,5 times (р=0.0039) respectively lower, compared to the control group. Conclusions: Doxorubicin-induced SI injury was associated with a significant decrease in plasma citrulline in rats regardless of NASH. The plasma citrulline could become an important marker in the assessment of the SI injury in clinical practice.

Acute Gastrointestinal Injury Score and its Prognostic Efficacy in Patients with Acute Necrotizing Pancreatitis

Introduction: Acute necrotizing pancreatitis (ANP) is potentially lethal inflammatory process. Recent researches established that presence of multiorgan failure together with pancreatic infection are major determinants of its mortality. But significance of acute gastrointestinal injury AGI in course of ANP is still remaining unclear. So aim of our study was to determine frequency and significance of AGI on severity and mortality of ANP. Material: We performed a prospective observational cohort study of 151 patients which were admitted to single intensive care department during early phase of ANP. Acute gastrointestinal injury was established according to ESICM recommendations. Clinical and laboratorial variables as well as plasma lipopolysaccharide, sCD14 receptors and citrulline concentrations were studied. Results: Different levels of AGI were diagnosed in 141 (93.4%) of patients with ANP. Risk of intestinal dysfunction (1st grade) was detected in 24.5% cases, feeding intolerance (2nd grade) - in 35.8%, intestinal failure (3rd grade) - in 33.2% and critical intestinal failure (4th grade) - in 8.0%. Intestinal (3rd and 4th grade of AGI), respiratory, cardio-vascular and renal failures were independent factors of mortality in multivariate logistic regression model (Wald's criteria 8.441, 5.464, 5.660 and 3.847, accordingly, p˂0.05). Conclusion: AGI is a frequent event during early phase of ANP. Intestinal failure (3rd and 4th grade of AGI) is strongly associated with unfavorable prognosis.

PSXII-4 Serum citrulline concentration of unweaned calves transported by road as a potential biomarker of gut functionality

Abstract In human’s serum citrulline concentration (SCC) have been proposed as a biomarker of small intestinal absorption. We hypothesize that the stress and feed restriction that unweaned calves suffer during transport impairs gut functionality reducing SCC. The aim of this study was to evaluate if road transport hours and adaptation period after arrival would affect SCC in unweaned calves. A total of 1,601 calves (3–4 wk of age; 65 ± 9 kg of BW) were transported with 8 trucks (n = 4 each journey): short transport (ST; &amp;lt; 9 h), and long transport with a rest stop proving feed and water to the calves (LT; &amp;gt; 9 h). A subset of 20 calves for each truck were sampled for SCC at arrival (t0), and 14 d after arrival (t14); in case of LT, also at arrival at the resting facility (t-1). SCC was analyzed using a commercial kit (intra- and inter-assay CV were 12.62% and 6.32%). Data was analyzed using a mixed model with journey hours and day as main effects, and calf and truck as random effects. SCC tended (P = 0.08) at t0 to be greater in LT (47.7 ± 3.39 mM) compared to ST (42.6 ± 2.46 mM). At t14 SCC increased in ST and LT calves; however, no differences were observed in SCC (55.9 ± 3.42 mM vs. 58.8 ± 2.52 mM for LT and ST, respectively). In LT calves rest stop did not affect SCC (43.2 ± 1.74 mM vs. 39.8 ± 1.76 mM for t-1 and t0, respectively), while at t14 (50.6 ± 1.86 mM) SCC was greater (P &amp;lt; 0.001) than t0 and t-1. The effect of transport type and evolution after transport on serum plasma citrulline concentrations may suggest that it’s a potential indicator of gut functionality in unweaned calves.

Plasma citrulline correlates with basolateral amino acid transporter LAT4 expression in human small intestine

Background & aimsPlasma citrulline, a non-protein amino acid, is a biochemical marker of small intestine enterocyte mass in humans. Indeed, citrulline is highly correlated with residual bowel length in patients with short bowel syndrome. It is known to be synthesised in epithelial cells of the small intestine from other amino acids (precursors). Citrulline is then released into systemic circulation and interconverted into arginine in kidneys. If plasma citrulline concentration depends on abundance of intestinal amino acid transporters is not known. The aim of the present study was to explore whether plasma citrulline concentration correlates with the expression of intestinal amino acid transporters. Furthermore, we assessed if arginine in urine correlates with plasma citrulline.MethodsDuodenal samples, blood plasma and urine were collected from 43 subjects undergoing routine gastroduodenoscopy. mRNA expression of seven basolateral membrane amino acid transporters/transporter subunits were assessed by real-time PCR. Plasma and urine amino acid concentrations of citrulline, its precursors and other amino acids were analysed using High Performance Liquid Chromatography measurements. Amino acid transporter mRNA expression was correlated with blood plasma and urine levels of citrulline and its precursors using Spearman's rank correlation. Likewise, urine arginine was correlated with plasma citrulline.ResultsPlasma citrulline correlated with the mRNA expression of basolateral amino acid transporter LAT4 (Spearman's r = 0.467, p = 0.028) in small intestine. None of the other basolateral membrane transporters/transporter subunits assessed correlated with plasma citrulline. Plasma citrulline correlated with urinary arginine, (Spearman's r = 0.419, p = 0.017), but not with urinary citrulline or other proteinogenic amino acids in the urine.ConclusionsIn this study, we showed for the first time that small intestinal basolateral LAT4 expression correlates with plasma citrulline concentration. This finding indicates that LAT4 has an important function in mediating citrulline efflux from enterocytes. Furthermore, urine arginine correlated with plasma citrulline, indicating arginine in the urine as possible additional marker for small intestine enterocyte mass. Finally, basolateral LAT4 expression along the human small intestine was shown for the first time.