Citrulline is a non-proteinogenic amino acid that forms as by-product in nitric oxide (NO) synthesis from arginine and may act in concert with NO as an independent signaling molecule that involves in the mechanism of vascular smooth muscle vasodilation. In this study we examined the effects of citrulline on pulmonary artery smooth muscles. Experimental design comprised outward potassium currents measurements in enzymatically isolated rat pulmonary artery smooth muscle (PASMc) cells using whole-cell patch clamp technique, isometric contractile force recordings on rat pulmonary artery rings and method of molecular docking simulation. Citrulline in a concentration 10-9-10-5 M relaxed phenylephrine (PHE)-preactivated SM of rat pulmonary artery in a dose-dependent manner (EC50 0,67 μM). This citrulline-induced relaxation was dependent on an intact endothelium. Bath application of citrulline (10-8-10-5 M) on isolated PASMc induced a significant increase in the amplitude of outward potassium current (Ik). The adenosine antagonist caffeine (10-6 M) effectively blocked both the citrulline-induced relaxation response and Ik increment. Molecular docking modeling suggests that caffeine blocking the potent activity of citrulline results from competitive interactions at the A2 adenosine receptor binding site. In summary, our data suggest that citrulline, released with NO at low concentrations, can effectively interact with adenosine receptors in smooth muscle cells, causing their relaxation, indicating surprising interaction between NO and adenosine pathways.

• MeSH
• arteria pulmonalis účinky léků   metabolismus   MeSH
• citrulin * farmakologie   metabolismus   MeSH
• krysa rodu rattus MeSH
• potkani Wistar MeSH
• purinergní receptory P1 metabolismus   MeSH
• simulace molekulového dockingu * MeSH
• svaly hladké cévní metabolismus   účinky léků   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• citrulin metabolismus   MeSH
• Citrullus * MeSH
• fytonutrienty klasifikace   MeSH
• kardiovaskulární nemoci * prevence a kontrola   MeSH
• lidé MeSH
• metaanalýza jako téma MeSH
• rizikové faktory kardiovaskulárních chorob MeSH
• Check Tag
• lidé MeSH

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.

• MeSH
• amoniak metabolismus   MeSH
• arginin terapeutické užití   MeSH
• citrulin MeSH
• hyperamonemie * farmakoterapie   MeSH
• karbamoylfosfát metabolismus   terapeutické užití   MeSH
• karbamoylfosfátsynthasa (amoniak) metabolismus   MeSH
• lidé MeSH
• nemoc z nedostatku ornithinkarbamoyltransferázy * chirurgie   MeSH
• ornithinkarbamoyltransferasa MeSH
• retrospektivní studie MeSH
• transplantace jater * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• pozorovací studie MeSH

The effects of L-citrulline or L-arginine supplementation on exercise performance are equivocal, and the effects on swimming performance are unclear. We aimed to assess whether 8-day supplementation with L-arginine or L-citrulline supplementation would improve 200 m and 100 m freestyle swimming time-trial performances. After the baseline trial (first visit), in a double-blind, randomised design, 15 trained/developmental (5 females) swimmers and triathletes were assigned to three groups and underwent an 8-day supplementation period, with a daily dose of either 8 gr L-arginine (Arg, n = 5) or L-citrulline (Cit, n = 5) or placebo (Pla, n = 5). On day 9, participants completed experimental trial (second visit). In each trial, after blood sampling, participants performed both 200 m and 100 m freestyle swimming time-trials, with 30 min recovery between trials. Plasma nitric oxide (NOx) and blood lactate concentrations (BLa) were collected immediately before and after 200 m and 100 m TTs, respectively. No significant difference was observed in NOx between groups (p = 0.201). There was no significant difference in 200 m (p = 0.226) and 100 m swimming time-trials (p = 0.993) between groups. There was a main effect of time on BLa concentration (p < 0.001), but no trial × group (p = 0.243) and trial × lactate × group interaction effect (p = 0.276) was present. Furthermore, 8-day either L-citrulline or L-arginine supplementation did not enhance middle (200 m) and short-distance (100 m) swimming performance in trained/developmental swimmers and triathletes. These findings do not support the use of L-citrulline or L-arginine supplementation as ergogenic aids for swimming performance.

• MeSH
• arginin MeSH
• citrulin * farmakologie   MeSH
• dvojitá slepá metoda MeSH
• kyselina mléčná MeSH
• lidé MeSH
• oxid dusnatý MeSH
• plavání * MeSH
• potravní doplňky MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• randomizované kontrolované studie MeSH

INTRODUCTION: To date, there is not generally accepted and universal indicator of activity, and functional integrity of the small intestine in patients with coeliac disease. The aim of our study was to investigate whether serum concentrations of the non-essential amino acids citrulline and ornithine might have this function. METHODS: We examined serum citrulline and ornithine concentrations in a subgroup of patients with proven coeliac disease and healthy controls (blood donors). RESULTS: A total of 94 patients with coeliac disease (29 men, mean age 53 ± 18 years; 65 women, mean age 44 ± 14 years) and 35 healthy controls (blood donors) in whom coeliac disease was serologically excluded (10 men, mean age 51 ± 14 years; 25 women, mean age 46 ± 12 years) were included in the study. Significantly lower concentrations of serum ornithine were found in patients with coeliac disease (mean 65 ± 3 μmol/L; median 63 μmol/L, IQR 34 μmol/L, p < 0.001). No statistically nor clinically significant differences were found in the citrulline concentrations between the study and control group. CONCLUSIONS: Serum ornithine (but not citrulline) may be useful for assessing the functional status of the small intestine in uncomplicated coeliac disease. Further studies involving more detailed analysis of dietary and metabolic changes in patients will be needed to reach definitive conclusions.

• MeSH
• celiakie * MeSH
• citrulin * metabolismus   MeSH
• dieta MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• ornithin metabolismus   MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

The presence or absence of autoantibodies against citrullinated proteins (ACPAs) distinguishes two main groups of rheumatoid arthritis (RA) patients with different etiologies, prognoses, disease severities, and, presumably, disease pathogenesis. The heterogeneous responses of RA patients to various biologics, even among ACPA-positive patients, emphasize the need for further stratification of the patients. We used high-density protein array technology for fingerprinting of ACPA reactivity. Identification of the proteome recognized by ACPAs may be a step to stratify RA patients according to immune reactivity. Pooled plasma samples from 10 anti-CCP-negative and 15 anti-CCP-positive RA patients were assessed for ACPA content using a modified protein microarray containing 1631 different natively folded proteins citrullinated in situ by protein arginine deiminases (PADs) 2 and PAD4. IgG antibodies from anti-CCP-positive RA plasma showed high-intensity binding to 87 proteins citrullinated by PAD2 and 99 proteins citrullinated by PAD4 without binding significantly to the corresponding native proteins. Curiously, the binding of IgG antibodies in anti-CCP-negative plasma was also enhanced by PAD2- and PAD4-mediated citrullination of 29 and 26 proteins, respectively. For only four proteins, significantly more ACPA binding occurred after citrullination with PAD2 compared to citrullination with PAD4, while the opposite was true for one protein. We demonstrate that PAD2 and PAD4 are equally efficient in generating citrullinated autoantigens recognized by ACPAs. Patterns of proteins recognized by ACPAs may serve as a future diagnostic tool for further subtyping of RA patients.

• MeSH
• autoantigeny krev   imunologie   MeSH
• biologické markery krev   MeSH
• čipová analýza proteinů MeSH
• citrulin metabolismus   MeSH
• citrulinace MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• peptidylarginindeiminasa typu 2 metabolismus   MeSH
• peptidylarginindeiminasa typu 4 metabolismus   MeSH
• protilátky proti citrulinovaným peptidům imunologie   MeSH
• revmatoidní artritida imunologie   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• tandemová hmotnostní spektrometrie MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The aim of our study was to assess the presence and degree of intestinal leakage in subjects suffering from short bowel syndrome (SBS) and its modification by parenteral nutrition. To this end we assessed circulating levels of selected makers of intestinal permeability including zonulin, fatty acid binding protein 2 (FABP-2), citrulline and glucagon-like peptide 2 (GLP-2). We also measured lipopolysaccharide binding protein (LBP) as a marker of circulating levels of lipopolysaccharide acting through the CD14 molecule. Eleven SBS and 10 age- and BMI-matched control subjects were included into the study. The effect of parenteral nutrition was assessed after 14 days, 6 and 12 months from its initiation, respectively. At baseline, SBS patients had increased gut permeability as measured by zonulin (47.24+/-2.14 vs. 39.48+/-1.20 ng/ml, p=0.006) and LBP (30.32+/-13.25 vs. 9.77+/-0.71 microg/ml, p<0.001) compared to healthy controls. Furthermore, SBS subjects had reduced FABP-2, unchanged citrulline and increased sCD14 and GLP-2 relative to control group. Throughout the whole study period the administered parenteral nutrition had no significant effect on any of the studied parameters. Taken together, our data show that patients with short bowel syndrome have increased intestinal permeability that is not affected by parenteral nutrition.

• MeSH
• biologické markery krev   MeSH
• citrulin krev   MeSH
• glukagonu podobný peptid 2 krev   MeSH
• haptoglobiny MeSH
• intestinální absorpce * MeSH
• lidé středního věku MeSH
• lidé MeSH
• membránové glykoproteiny krev   MeSH
• parenterální výživa * MeSH
• permeabilita MeSH
• proteinové prekurzory krev   MeSH
• proteiny akutní fáze MeSH
• proteiny vázající mastné kyseliny krev   MeSH
• senioři MeSH
• studie případů a kontrol MeSH
• syndrom krátkého střeva diagnóza   krev   patofyziologie   terapie   MeSH
• tenké střevo metabolismus   patofyziologie   MeSH
• transportní proteiny krev   MeSH
• výsledek terapie MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Citrullination is a post-translational protein modification, which is associated with inflammation in general and is thought to play an important pathogenic role in rheumatoid arthritis (RA). Here a mass spectrometry-based proteomics approach was applied to identify citrullination sites in synovial fluid fibrinogen from four RA patients. In general, high disease activity correlated with increased number of identified citrullination sites and higher relative citrulline occupancy. Altogether, 23 sites were identified, of which 9 have not been previously reported to be citrullinated in vivo. Citrullination at site α84, α123, α129, α547, α573, α591, β334 and γ134 was identified in more than one patient, and these positions were therefore regarded as hotspots. Following citrullination of fibrinogen in vitro using human recombinant peptidylarginine deiminase 2 (PAD2), a total of 46 citrullination sites were identified, including 6 hitherto unreported in vitro citrullination sites. Twenty-two out of the 23 citrullination sites identified in vivo were also detected in vitro, supporting the validity of the identifications. SIGNIFICANCE: This work provides information about previously uncharacterized citrullination sites in synovial fluid fibrinogen from rheumatoid arthritis patients. Detection of these novel citrullination sites may prove to have diagnostic or prognostic value in RA and enhance our understanding of the immune pathogenesis.

• MeSH
• citrulin metabolismus   MeSH
• fibrinogen metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• peptidylarginindeiminasa typu 2 MeSH
• posttranslační úpravy proteinů * MeSH
• proteomika MeSH
• revmatoidní artritida metabolismus   patologie   MeSH
• senioři MeSH
• synoviální membrána metabolismus   patologie   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: Patients with chronic intestinal failure (CIF) often develop cholestatic liver injury, which may lead to liver failure and need for organ transplantation. OBJECTIVES: The aim of this study was to investigate whether citrulline (CIT) and the enterokine fibroblast growth factor 19 (FGF19) are associated with chronic cholestasis and survival in adult CIF patients, and to develop a risk score to predict their survival. METHODS: We studied 135 adult CIF patients on intravenous supplementation (>3 mo). Associations of plasma CIT and FGF19 with chronic cholestasis and survival were estimated by logistic and Cox regression models. A predictive risk score was developed and validated internally. RESULTS: Patients with chronic cholestasis (17%) had a reduced 5-y survival rate compared with patients without chronic cholestasis (38% and 62%, respectively). In multivariable analysis, low FGF19, low CIT, and female sex were associated with chronic cholestasis. Patients with low rather than high CIT or FGF19 also had reduced 5-y survival rates (29% compared with 69%; 54% compared with 66%, respectively). Risk factors identified in multivariable analysis of survival were low FGF19 (HR: 3.4), low CIT (HR: 3.3), and number of intravenous infusions per week (HR: 1.4). These 3 predictors were incorporated in a risk model of survival termed Model for End-Stage Intestinal Failure (MESIF) (C-statistic 0.78). The 5-y survival rates for patients with MESIF scores of 0 to <20 (n = 47), 20-40 (n = 75), and >40 (n = 13) were 80%, 58%, and 14%, respectively. CONCLUSIONS: CIT and FGF19 predict chronic cholestasis and survival in this cohort of adult CIF patients, and the derived MESIF score is associated with their survival. Pending external validation, the MESIF score may help to identify patients for closer clinical monitoring or earlier referral to intestinal transplantation centers.

• MeSH
• cholestáza krev   etiologie   mortalita   MeSH
• chronická nemoc mortalita   MeSH
• citrulin krev   MeSH
• dospělí MeSH
• fibroblastové růstové faktory krev   MeSH
• lidé středního věku MeSH
• lidé MeSH
• nemoci střev komplikace   MeSH
• prospektivní studie MeSH
• retrospektivní studie MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

LL-37, the only human cathelicidin that is released during inflammation, is a potent regulator of immune responses by facilitating delivery of oligonucleotides to intracellular TLR-9, thereby enhancing the response of human plasmacytoid dendritic cells (pDCs) to extracellular DNA. Although important for pathogen recognition, this mechanism may facilitate development of autoimmune diseases. In this article, we show that citrullination of LL-37 by peptidyl-arginine deiminases (PADs) hindered peptide-dependent DNA uptake and sensing by pDCs. In contrast, carbamylation of the peptide (homocitrullination of Lys residues) had no effect. The efficiency of LL-37 binding to oligonucleotides and activation of pDCs was found to be inversely proportional to the number of citrullinated residues in the peptide. Similarly, preincubation of carbamylated LL-37 with PAD2 abrogated the peptide's ability to bind DNA. Conversely, LL-37 with Arg residues substituted by homoarginine, which cannot be deiminated, elicited full activity of native LL-37 regardless of PAD2 treatment. Taken together, the data showed that citrullination abolished LL-37 ability to bind DNA and altered the immunomodulatory function of the peptide. Both activities were dependent on the proper distribution of guanidinium side chains in the native peptide sequence. Moreover, our data suggest that cathelicidin/LL-37 is citrullinated by PADs during NET formation, thus affecting the inflammatory potential of NETs. Together this may represent a novel mechanism for preventing the breakdown of immunotolerance, which is dependent on the response of APCs to self-molecules (including cell-free DNA); overactivation may facilitate development of autoimmunity.

• MeSH
• autoimunita imunologie   MeSH
• biologický transport MeSH
• buněčné linie MeSH
• citrulin metabolismus   MeSH
• citrulinace fyziologie   MeSH
• dendritické buňky imunologie   MeSH
• DNA imunologie   metabolismus   MeSH
• imunologická tolerance imunologie   MeSH
• kationické antimikrobiální peptidy metabolismus   MeSH
• lidé MeSH
• myši MeSH
• peptidylarginindeiminasy metabolismus   MeSH
• RAW 264.7 buňky MeSH
• volné cirkulující nukleové kyseliny imunologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH