Citrulline supplementation exacerbates sepsis severity in infected preterm piglets via early induced immunosuppression.

Arginine (ARG)/Citrulline (CIT) deficiency is associated with increased sepsis severity after infection. Supplementation of CIT to susceptible patients with ARG/CIT deficiency such as preterm newborns with suspected infection might prevent sepsis, via maintaining immune and vascular function. Caesarean-delivered, parenterally nourished preterm pigs were treated with CIT (1g/kg bodyweight) via oral or continuous intravenous supplementation, then inoculated with live Staphylococcus epidermidis and clinically monitored for 14 h. Blood, liver, and spleen samples were collected for analysis. In vitro cord blood stimulation was performed to explore how CIT and ARG affect premature blood cell responses. After infection, oral CIT supplementation led to higher mortality, increased blood bacterial load, and systemic and hepatic inflammation. Intravenous CIT administration showed increased inflammation and bacterial burdens without significantly affecting mortality. Liver transcriptomics and data from in vitro blood stimulation indicated that CIT induces systemic immunosuppression in preterm newborns, which may impair resistance response to bacteria at the early stage of infection, subsequently causing later uncontrollable inflammation and tissue damage. The early stage of CIT supplementation exacerbates sepsis severity in infected preterm pigs, likely via inducing systemic immunosuppression.

L-Citrulline Supplementation Improves Arterial Blood Flow and Muscle Oxygenation during Handgrip Exercise in Hypertensive Postmenopausal Women.

Endothelial dysfunction decreases exercise limb blood flow (BF) and muscle oxygenation. Acute L-Citrulline supplementation (CIT) improves muscle tissue oxygen saturation index (TSI) and deoxygenated hemoglobin (HHb) during exercise. Although CIT improves endothelial function (flow-mediated dilation [FMD]) in hypertensive women, the impact of CIT on exercise BF and muscle oxygenation (TSI) and extraction (HHb) are unknown. We examined the effects of CIT (10 g/day) and a placebo for 4 weeks on blood pressure (BP), arterial vasodilation (FMD, BF, and vascular conductance [VC]), and forearm muscle oxygenation (TSI and HHb) at rest and during exercise in 22 hypertensive postmenopausal women. Compared to the placebo, CIT significantly (p < 0.05) increased FMD (Δ-0.7 ± 0.6% vs. Δ1.6 ± 0.7%) and reduced aortic systolic BP (Δ3 ± 5 vs. Δ-4 ± 6 mmHg) at rest and improved exercise BF (Δ17 ± 12 vs. Δ48 ± 16 mL/min), VC (Δ-21 ± 9 vs. Δ41 ± 14 mL/mmHg/min), TSI (Δ-0.84 ± 0.58% vs. Δ1.61 ± 0.46%), and HHb (Δ1.03 ± 0.69 vs. Δ-2.76 ± 0.77 µM). Exercise BF and VC were positively correlated with improved FMD and TSI during exercise (all p < 0.05). CIT improved exercise artery vasodilation and muscle oxygenation via increased endothelial function in hypertensive postmenopausal women.

L-Citrullinato-Bipyridine and L-Citrullinato-Phenanthroline Mixed Copper Complexes: Synthesis, Characterization and Potential Anticancer Activity.

Citrulline (C6H13N3O3) is an amino acid found in the body as a zwitterion. This means its carboxylic and amine groups can act as Lewis donors to chelate metal cations. In addition, citrulline possesses a terminal ureido group on its aliphatic chain, which also appears to coordinate. Here, two new mixed complexes of citrulline were made with 1,10-phenanthroline and 2,2'-bipyridine. These compounds, once dissolved in water, gave aquo-complexes that were subject to DFT studies and in vitro toxicity studies on cancer cell lines (HeLa, MDA-MB-231, HCT 15, and MCF7) showed promising results. Docking studies with DNA were also conducted, indicating potential anticancer properties.

Clinical, biochemical, and molecular profiles of three Sri Lankan neonates with pyruvate carboxylase deficiency.

Objectives: Pyruvate carboxylase, a mitochondrial enzyme, catalyses the conversion of glycolytic end-product pyruvate to tricarboxylic acid cycle intermediate, oxaloacetate. Rare pyruvate carboxylase deficiency manifests in three clinical and biochemical phenotypes: neonatal onset type A, infantile onset type B and a benign C type. The objective of this case series is to expand the knowledge of overlapping clinical and biochemical phenotypes of pyruvate carboxylase deficiency. Case presentation: We report three Sri Lankan neonates including two siblings, of two unrelated families with pyruvate carboxylase deficiency. All three developed respiratory distress within the first few hours of birth. Two siblings displayed typical biochemical findings reported in type B. The other proband with normal citrulline, lysine, moderate lactate, paraventricular cystic lesions, bony deformities, and a novel missense, homozygous variant c.2746G>C [p.(Asp916His)] in the PC gene, biochemically favoured type A. Conclusions: Our findings indicate the necessity of prompt laboratory investigations in a tachypneic neonate with coexisting metabolic acidosis, as early recognition is essential for patient management and family counselling. Further case studies are required to identify overlapping symptoms and biochemical findings in different types of pyruvate carboxylase deficiency phenotypes.

Rational design to improve the catalytic efficiency and stability of arginine deiminase.

Arginine deiminase (ADI) has garnered significant interest because of its ability to objectively eradicate cancer cells and produce L-citrulline. To meet the production demands, this study focused on enhancing the enzyme activity and thermal stability of ADI. In this study, 24 ADI mutants were obtained through computer aid site-specific mutation in the ADI of Enterobacter faecalis. Notably, the specific enzyme activities of F44W, N163P, E220I, E220L, N318E, A336G, T340I, and N382F increased, reaching 1.33-2.53 times that of the original enzyme. This study confirmed that site-specific mutations are critical for optimizing enzyme function. Additionally, the F44W, N163P, E220I, T340I, and A336G mutants demonstrated good thermal stability. The optimal pH for mutant F44W increased to 8, whereas mutants E220I, I244V, A336G, T340I, and N328F maintained an optimal pH of 7.5. Conversely, the M109L, N163P, E220L, I244L, and N318E mutants shad an optimal pH of 7. This study revealed that mutant enzymes with increased activity were more likely to contain mutation sites situated near the four loops associated with catalytic residues, whereas mutations at the dimer junction sites had a higher tendency to enhance enzyme stability. These findings contribute to the development of ADI industrial applications and its modifications.

Empagliflozin increases plasma levels of citrulline, histidine, and α-aminobutyric acid in patients with type 2 diabetes: effects of a sodium-glucose co-transporter 2 inhibitor on the plasma amino acid profile.

BACKGROUND: To investigate effects of empagliflozin on plasma amino acids in people with type 2 diabetes. RESEARCH DESIGN AND METHODS: In a randomized, active-controlled, open-label trial, 58 patients with type 2 diabetes were randomized to 10 mg/day empagliflozin (n = 29) or standard treatment without empagliflozin (control group, n = 29) and treated for 12 weeks. We obtained blood samples at baseline and 12 weeks and assessed the plasma amino acid profile by liquid chromatography-mass spectrometry liquid chromatography. We also calculated the Fischer ratio (the ratio of branched-chain to aromatic amino acids). RESULTS: In the empagliflozin group but not in the control group, plasma levels of citrulline, histidine, and α-aminobutyric acid (AABA), the Fischer ratio, and serum high-molecular weight (HMW) adiponectin increased significantly (p = 0.0099, 0.0277, 0.0318, 0.0135, and 0.0304, respectively) and plasma plasminogen activator inhibitor-1 (PAI-1) decreased significantly (p = 0.0014). In the empagliflozin group, the change in plasma citrulline was positively correlated with the changes in HMW adiponectin (r = 0.488, p = 0.0084) and the Fischer ratio (r = 0.393, p = 0.0353) but negatively correlated with the change in ferritin (r= -0.533,p = 0.0051); the change in plasma histidine was negatively correlated with the change in PAI-1 (r= -0.398, p = 0.0397) and urinary albumin creatinine ratio (r= -0.478, p = 0.0088). CONCLUSION: Empagliflozin significantly increases plasma citrulline, histidine, and AABA in people with type 2 diabetes. CLINICAL TRIAL REGISTRATION: www.umin.ac.jp identifier is UMIN000025418.

Gut microbial alterations in arginine metabolism determine bone mechanical adaptation.

Although mechanical loading is essential for maintaining bone health and combating osteoporosis, its practical application is limited to a large extent by the high variability in bone mechanoresponsiveness. Here, we found that gut microbial depletion promoted a significant reduction in skeletal adaptation to mechanical loading. Among experimental mice, we observed differences between those with high and low responses to exercise with respect to the gut microbial composition, in which the differential abundance of Lachnospiraceae contributed to the differences in bone mechanoresponsiveness. Microbial production of L-citrulline and its conversion into L-arginine were identified as key regulators of bone mechanoadaptation, and administration of these metabolites enhanced bone mechanoresponsiveness in normal, aged, and ovariectomized mice. Mechanistically, L-arginine-mediated enhancement of bone mechanoadaptation was primarily attributable to the activation of a nitric-oxide-calcium positive feedback loop in osteocytes. This study identifies a promising anti-osteoporotic strategy for maximizing mechanical loading-induced skeletal benefits via the microbiota-metabolite axis.

Icarifil® in Association with Daily Use of Tadalafil (5 mg) versus Standard Tadalafil Daily Dose (5 mg) or Alone: Results from a Controlled, Randomized Clinical Trial.

Background: The management of erectile dysfunction (ED) shows several grey zones and new treatments are required to reduce the percentage of patients discontinuing treatment. Here, we aim to evaluate the role of a natural mixture named Icarifil® (L-Citrulline, L-Carnitine, Eruca vesicaria, Panax ginseng, Tribulus terrestris, Turnera diffusa, Taurine, Vitamin E, Zinc) in the management of patients with ED. Methods: From September 2022 to March 2023, all patients attending 3 urological institutions due to ED were randomized to receive the following for 3 months: Icarifil® 1 sachet every 24 h (Group 1) or Icarifil® 1 sachet + tadalafil 5 mg 1 tablet every 24 h (Group 2) or tadalafil 5 mg 1 tablet daily (Group 3). All patients underwent urologic visits and dedicated questionnaires (IIEF-5, SEP-2, SEP-3) at enrollment and at the follow-up evaluation (3 months). Patient-Reported Outcomes (PROs) at the follow-up evaluation were used. The primary endpoint was the difference in the questionnaires at the follow-up visit compared to the one at enrollment among the study groups. Results: In the per-protocol analysis, 52 patients in Group 1, 55 in Group 2 and 57 in Group 3 were analyzed. At the follow-up evaluation, IIEF-5 scores improved in all the 3 groups between enrollment and the follow-up evaluation, but a statistically significant difference was reported between Group 2 (+7.4) and Group 1 (+4.1) or Group 3 (+5.1), (p < 0.001; p < 0.001). Moreover, 47 patients (94.0%) in Group 2 showed an improvement in the SEP questionnaires, when compared with the baseline, while 29 in Group 1 (56.9%) and 42 in Group 3 (82.3%) showed a statistically significant difference (p = 0.004; p = 0.003) among the groups. The PRO analysis reported better efficacy and patient satisfaction in Group 2 when compared with Group 1 or Group 3. Conclusions: In conclusion, Icarifil® is able to improve penile erectile function in mild-moderate ED and significantly improve the clinical efficacy of daily used tadalafil 5 mg. Icarifil® could represent an interesting alternative treatment in patients experiencing adverse effects or with contraindications for chronic treatment with PDE5-is.

Citrulline facilitates the glycolysis, proliferation, and metastasis of lung cancer cells by regulating RAB3C.

Lung cancer (LC) is one of the major malignant diseases threatening human health. The study aimed to identify the effect of citrulline on the malignant phenotype of LC cells and to further disclose the potential molecular mechanism of citrulline in regulating the development of LC, providing a novel molecular biological basis for the clinical treatment of LC. The effects of citrulline on the viability, proliferation, migration, and invasion of LC cells (A549, H1299) were validated by CCK-8, colony formation, EdU, and transwell assays. The cell glycolysis was assessed via determining the glucose uptake, lactate production, ATP levels, extracellular acidification rate (ECAR), and oxygen consumption rate (OCR). RNA-seq and molecular docking were performed to screen for citrulline-binding target proteins. Western blotting experiments were conducted to examine the expression of related signaling pathway molecules. In addition, the impacts of citrulline on LC growth in vivo were investigated by constructing mouse models. Citrulline augmented the viability of LC cells in a concentration and time-dependent manner. The proliferation, migration, invasion, glycolysis, and EMT processes of LC cells were substantially enhanced after citrulline treatment. Bioinformatics analysis indicated that citrulline could bind to RAB3C protein. Western blotting results indicated that citrulline activated the IL-6/STAT3 pathway by binding to RAB3C. In addition, animal experiments disclosed that citrulline promoted tumor growth in mice. Citrulline accelerated the glycolysis and activated the IL6/STAT3 pathway through the RAB3C protein, consequently facilitating the development of LC.

Type 2 diabetes mellitus remission in sleeve gastrectomy patients: Role of enteroendocrine response and serum citrulline and I-FABP levels.

INTRODUCTION: This prospective cohort study examines the relationship between post-sleeve gastrectomy (SG) weight loss and serum citrulline, I-FABP levels, and the I-FABP/citrulline ratio in obese patients, alongside the correlation with type 2 diabetes mellitus (T2DM) remission. METHODS: 88 participants were enrolled, including 48 undergoing SG and 21 with T2DM. 40 healthy individuals served as controls. Preoperative and 1-year postoperative assessments included citrulline, I-FABP, glucose, insulin, HbA1c, and C peptide levels. RESULTS: Significant weight loss and T2DM remission (11/21) were observed post-SG. Preoperatively, patients had low citrulline and high I-FABP levels, which normalized postoperatively. A positive correlation was found between the I-FABP/citrulline ratio and weight, BMI, glucose, insulin, and C peptide levels. CONCLUSION: SG not only induces enterocyte dysfunction and mass recovery but also may facilitate T2DM remission and alleviate obesity-related effects on the enteroendocrine system. These findings highlight the potential beneficial effects of SG on enteroendocrine function in obese patients.

L-Citrulline Ameliorates Iron Metabolism and Mitochondrial Quality Control via Activating AMPK Pathway in Intestine and Improves Microbiota in Mice with Iron Overload.

SCOPE: Oxidative stress caused by iron overload tends to result in intestinal mucosal barrier dysfunction and intestinal microbiota imbalance. As a neutral and nonprotein amino acid, L-Citrulline (L-cit) has been implicated in antioxidant and mitochondrial amelioration properties. This study investigates whether L-cit can alleviate iron overload-induced intestinal injury and explores the underlying mechanisms. METHODS AND RESULTS: C57BL/6J mice are intraperitoneally injected with iron dextran, then gavaged with different dose of L-cit for 2 weeks. L-cit treatment significantly alleviates intestine pathological injury, oxidative stress, ATP level, and mitochondrial respiratory chain complex activities, accompanied by ameliorating mitochondrial quality control. L-cit-mediated protection is associated with the upregulation of Glutathione Peroxidase 4 (GPX4) expression, inhibition Nuclear Receptor Coactivator 4 (NCOA4)-mediated ferritinophagy and ferroptosis, and improvement of gut microbiota. To investigate the underlying molecular mechanisms, Intestinal Porcine Epithelial Cell line-J2 (IPEC-J2) cells are treated with L-cit or AMP-activated Protein Kinase (AMPK) inhibitor. AMPK signaling has been activated by L-cit. Notably, Compound C abolishes L-cit's protection on intestinal barrier, mitochondrial function, and antioxidative capacity in IPEC-J2 cells. CONCLUSION: L-cit may restrain ferritinophagy and ferroptosis to regulate iron metabolism, and induce AMPK pathway activation, which contributes to exert antioxidation, ameliorate iron metabolism and mitochondrial quality control, and improve intestinal microbiota. L-cit is a promising therapeutic strategy for iron overload-induced intestinal injury.

Arginine metabolomics in mood disorders.

Alterations of nitric oxide (NO) homeostasis have been described in mood disorders. However, the analytical challenges associated with the direct measurement of NO have prompted the search for alternative biomarkers of NO synthesis. We investigated the published evidence of the association between these alternative biomarkers and mood disorders (depressive disorder or bipolar disorder). Electronic databases were searched from inception to the June 30, 2023. In 20 studies, there was a trend towards significantly higher asymmetric dimethylarginine (ADMA) in mood disorders vs. controls (p = 0.072), and non-significant differences in arginine (p = 0.29), citrulline (p = 0.35), symmetric dimethylarginine (SDMA; p = 0.23), and ornithine (p = 0.42). In subgroup analyses, the SMD for ADMA was significant in bipolar disorder (p < 0.001) and European studies (p = 0.02), the SMDs for SDMA (p = 0.001) and citrulline (p = 0.038) in European studies, and the SMD for ornithine in bipolar disorder (p = 0.007), Asian (p = 0.001) and American studies (p = 0.005), and patients treated with antidepressants (p = 0.029). The abnormal concentrations of ADMA, SDMA, citrulline, and ornithine in subgroups of mood disorders, particularly bipolar disorder, warrant further research to unravel their pathophysiological role and identify novel treatments in this group (The protocol was registered in PROSPERO: CRD42023445962).

Anti-Inflammatory Activity of Cyanobacteria Pigment Extracts: Physiological Free Radical Scavenging and Modulation of iNOS and LOX Activity.

Cyanobacteria are among the oldest organisms colonizing Earth. Their great biodiversity and ability to biosynthesize secondary metabolites through a variety of routes makes them attractive resources for biotechnological applications and drug discovery. In this pioneer study, four filamentous cyanobacteria (Cephalothrix lacustris LEGE 15493, Leptolyngbya boryana LEGE 15486, Nodosilinea nodulosa LEGE 06104 and Leptothoe sp. LEGE 11479) were explored for their anti-inflammatory potential in cell and cell-free in vitro bioassays, involving different inflammatory mediators and enzymes. Extracts of different polarities were sequentially prepared and chemically characterized for their content of phycobiliproteins (PBPs) and carotenoids. HPLC-PDA analysis of the acetone extracts revealed ß-carotene to be the dominant carotenoid (18.4-44.3 mg/g) and zeaxanthin as the dominant xanthophyll (52.7-192.9 mg/g), with Leptothoe sp. LEGE 11479 and Nodosilinea nodulosa LEGE 06104, respectively, being the richest strains. The PBP profile was in accordance with the color presented by the aqueous extracts, with Leptolyngbya boryana LEGE 15486 being the richest in phycocyanin (204.5 µg/mg) and Leptothoe sp. LEGE 11479 the richest in phycoerythrin (78.5 µg/mg). Aqueous extracts were more effective in superoxide anion radical scavenging, while acetone ones were more effective in scavenging nitric oxide radical (●NO) and in inhibiting lipoxygenase. Acetone extracts also reduced ●NO production in lipopolysaccharide-stimulated RAW 264.7 macrophages, with the mechanistic study suggesting a downregulation of the inducible nitric oxide synthase expression. Nodosilinea nodulosa LEGE 06104 and Leptothoe sp. LEGE 11479 acetone extracts presented the lowest IC50 values for the mentioned assays, pointing them out as promising resources for the development of new multi-target anti-inflammatory therapies.

Biomarkers of Immunotherapy Response in Patients with Non-Small-Cell Lung Cancer: Microbiota Composition, Short-Chain Fatty Acids, and Intestinal Permeability.

Immune checkpoint inhibitors have been proposed as the standard treatment for different stages of non-small-cell lung cancer in multiple indications. Not all patients benefit from these treatments, however, and certain patients develop immune-related adverse events. Although the search for predictors of response to these drugs is a major field of research, these issues have yet to be resolved. It has been postulated that microbiota could play a relevant role in conditioning the response to cancer treatments; however, the human factor of intestinal permeability also needs to be considered as it is closely related to the regulation of host-microbiota interaction. In this article, we analyzed the possible relationship between the response to immune checkpoint inhibitors and the onset of immune-related adverse events, gut microbiota status, and intestinal membrane permeability. In a pioneering step, we also measured short-chain fatty acid content in feces. Although the correlation analyses failed to identify predictive biomarkers, even when all variables were integrated, our patients' microbial gut ecosystems were rich and diverse, and the intestinal barrier's integrity was preserved. These results add new knowledge on the composition of microbiota and its correlation with barrier permeability and short-chain fatty acids and suggest that more studies are required before these potential biomarkers can be incorporated into the clinical management of patients via immune checkpoint inhibitor treatment.

Antenatal Growth, Gestational Age, Birth, Enteral Feeding, and Blood Citrulline Levels in Very Low Birth Weight Infants.

Early enteral nutrition using reliable biomarkers of intestinal function must be established to improve neurodevelopmental outcomes in very low birth weight infants (VLBWIs). Serum citrulline levels reflect the intestinal function in adults. To elucidate the relationship among antenatal growth, postnatal enteral nutrition, and blood citrulline levels, a retrospective single-center observational study was conducted on 248 VLBWIs born between April 2014 and March 2021. A mixed effect model and post hoc simple slope analysis were used to estimate the correlations between clinical variables and citrulline levels at Early (day 5.1) and Late (day 24.3) postnatal ages. Greater gestational age, birth weight, and amount of enteral nutrition at the time of blood sampling were associated with lower citrulline levels at the Early postnatal age and higher citrulline levels at the Late postnatal age. Provided that Early citrulline levels predominantly reflect the consequence of antenatal citrulline metabolism, it is suggested that fetal growth and maturation are likely to promote citrulline catabolism in utero and its synthesis after birth. With additional insights into the temporal transition point wherein the maturation-dependent balance of citrulline metabolism shifts from catabolism-dominant to synthesis-dominant, citrulline emerges as a potential biomarker for assessing intestinal function and gastrointestinal disorders.

Development of a Two-Dimensional Liquid Chromatographic Method for Analysis of Urea Cycle Amino Acids.

The urea cycle has been found to be closely associated with certain types of cancers and other diseases such as cardiovascular disease and chronic kidney disease. An analytical method for the precise quantification of urea cycle amino acids (arginine, ornithine, citrulline, and argininosuccinate) by off-line two-dimensional liquid chromatography (2D-LC) combined with fluorescence-based detection was developed. Before analysis, the amino acids were derivatised with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) to obtain NBD-amino acids. The first dimension involved the reversed-phase separation, in which NBD derivatives of urea cycle amino acids were completely separated from each other and mostly separated from the 18 NBD-proteinogenic amino acids. The samples were eluted with stepwise gradient using 0.02% trifluoroacetic acid in water-acetonitrile as the mobile phase. In the second dimension, an amino column was used for the separation of NBD-ornithine, -citrulline, and -argininosuccinate, while a sulfonic acid column was used to separate NBD-arginine. The developed 2D-LC system was used to analyse human plasma samples. The fractions of NBD-urea cycle amino acids obtained in the first dimension were collected manually and introduced into the second dimension. By choosing appropriate mobile phases for the second dimension, each NBD-urea cycle amino acid eluted in the first dimension was well separated from the other proteinogenic amino acids and interference from endogenous substance. This could not be achieved in the first dimension. The urea cycle amino acids in human plasma sample were quantified, and the method was well validated. The calibration curves for each NBD-urea cycle amino acid showed good linearity from 3 (ASA) or 15 (Orn, Cit, and Arg) to 600 nM, with correlation coefficients higher than 0.9969. The intraday and interday precisions were less than 7.9% and 15%, respectively. The 2D-LC system is expected to be useful for understanding the involvement of the urea cycle in disease progression.

Measurements of I-FABP and citrulline in the postoperative period of non-cardiac surgeries with gastrointestinal complications: A prospective cohort observational study.

BACKGROUND: Acute Gastrointestinal Injury (AGI) is associated with adverse clinical outcomes, including increased mortality. We aimed to investigate the potential of citrulline and intestinal fatty acid binding protein (I-FABP) as biomarkers for early AGI diagnosis and predicting outcomes in surgical patients. METHODS: Prospective cohort study involving patients who underwent non-cardiac surgeries and were admitted to Intensive Care Units. AGI diagnosis was based on specific criteria, and severity was categorised following established guidelines. Statistical analyses were performed to assess the diagnostic accuracy of the biomarkers and their association with outcomes, P significant when <0.05. RESULTS: AGI was identified in 40.3% of patients with varying severity. Mortality rates were significantly higher in the AGI group in the ICU (19.4% vs. 0%, p = 0.001) and hospital (22.6% vs. 2.17%, p = 0.003). Urinary I-FABP levels on days 3 and 7 showed reasonable and good accuracy for AGI diagnosis (AUC 0.732 and 0.813, respectively). Urinary I-FABP levels on days 2 and 3 accurately predict sepsis. Urinary citrulline levels on day one predicted mortality (AUC 0.87) furthermore urinary I-FABP levels on day 2 showed reasonable accuracy (sensitivity 83.3%, specificity 92.4%). CONCLUSION: Urinary I-FABP and citrulline levels are promising diagnostic and prognostic markers in ICU patients following non-cardiac surgeries.

Impact of citrulline substitution on clinical outcome after liver transplantation in carbamoyl phosphate synthetase 1 and ornithine transcarbamylase deficiency.

Carbamoyl phosphate synthetase 1 (CPS1) and ornithine transcarbamylase (OTC) deficiencies are rare urea cycle disorders, which can lead to life-threatening hyperammonemia. Liver transplantation (LT) provides a cure and offers an alternative to medical treatment and life-long dietary restrictions with permanent impending risk of hyperammonemia. Nevertheless, in most patients, metabolic aberrations persist after LT, especially low plasma citrulline levels, with questionable clinical impact. So far, little is known about these alterations and there is no consensus, whether l-citrulline substitution after LT improves patients' symptoms and outcomes. In this multicentre, retrospective, observational study of 24 patients who underwent LT for CPS1 (n = 11) or OTC (n = 13) deficiency, 25% did not receive l-citrulline or arginine substitution. Correlation analysis revealed no correlation between substitution dosage and citrulline levels (CPS1, p = 0.8 and OTC, p = 1). Arginine levels after liver transplantation were normal after LT independent of citrulline substitution. Native liver survival had no impact on mental impairment (p = 0.67). Regression analysis showed no correlation between l-citrulline substitution and failure to thrive (p = 0.611) or neurological outcome (p = 0.701). Peak ammonia had a significant effect on mental impairment (p = 0.017). Peak plasma ammonia levels correlate with mental impairment after LT in CPS1 and OTC deficiency. Growth and intellectual impairment after LT are not significantly associated with l-citrulline substitution.

Impact of supplementation with L-citrulline/arginine after liver transplantation in individuals with Urea Cycle Disorders.

OBJECTIVE: Liver transplantation (LTx) is an intervention when medical management is not sufficiently preventing individuals with urea cycle disorders (UCDs) from the occurrence of hyperammonemic events. Supplementation with L-citrulline/arginine is regularly performed prior to LTx to support ureagenesis and is often continued after the intervention. However, systematic studies assessing the impact of long-term L-citrulline/arginine supplementation in individuals who have undergone LTx is lacking to date. METHODS: Using longitudinal data collected systematically, a comparative analysis was carried out by studying the effects of long-term L-citrulline/arginine supplementation vs. no supplementation on health-related outcome parameters (i.e., anthropometric, neurological, and cognitive outcomes) in individuals with UCDs who have undergone LTx. Altogether, 52 individuals with male ornithine transcarbamylase deficiency, citrullinemia type 1 and argininosuccinic aciduria and a pre-transplant "severe" disease course who have undergone LTx were investigated by using recently established and validated genotype-specific in vitro enzyme activities. RESULTS: Long-term supplementation of individuals with L-citrulline/arginine who have undergone LTx (n = 16) does neither appear to alter anthropometric nor neurocognitive endpoints when compared to their severity-adjusted counterparts that were not supplemented (n = 36) after LTx with mean observation periods between four to five years. Moreover, supplementation with L-citrulline/arginine was not associated with an increase of disease-specific plasma arithmetic mean values for the respective amino acids when compared to the non-supplemented control cohort. CONCLUSION: Although supplementation with L-citrulline/arginine is often continued after LTx, this pilot study does neither identify altered long-term anthropometric or neurocognitive health-related outcomes nor does it find an adequate biochemical response as reflected by the unaltered plasma arithmetic mean values for L-citrulline or L-arginine. Further prospective analyses in larger samples and even longer observation periods will provide more insight into the usefulness of long-term supplementation with L-citrulline/arginine for individuals with UCDs who have undergone LTx.

Perinatal Use of Citrulline Rescues Hypertension in Adult Male Offspring Born to Pregnant Uremic Rats.

The growing recognition of the association between maternal chronic kidney disease (CKD) and fetal programming highlights the increased vulnerability of hypertension in offspring. Potential mechanisms involve oxidative stress, dysbiosis in gut microbiota, and activation of the renin-angiotensin system (RAS). Our prior investigation showed that the administration of adenine to pregnant rats resulted in the development of CKD, ultimately causing hypertension in their adult offspring. Citrulline, known for enhancing nitric oxide (NO) production and possessing antioxidant and antihypertensive properties, was explored for its potential to reverse high blood pressure (BP) in offspring born to CKD dams. Male rat offspring, both from normal and adenine-induced CKD models, were randomly assigned to four groups (8 animals each): (1) control, (2) CKD, (3) citrulline-treated control rats, and (4) citrulline-treated CKD rats. Citrulline supplementation successfully reversed elevated BP in male progeny born to uremic mothers. The protective effects of perinatal citrulline supplementation were linked to an enhanced NO pathway, decreased expression of renal (pro)renin receptor, and changes in gut microbiota composition. Citrulline supplementation led to a reduction in the abundance of Monoglobus and Streptococcus genera and an increase in Agothobacterium Butyriciproducens. Citrulline's ability to influence taxa associated with hypertension may be linked to its protective effects against maternal CKD-induced offspring hypertension. In conclusion, perinatal citrulline treatment increased NO availability and mitigated elevated BP in rat offspring from uremic mother rats.