No abstract available.
Arthritis, Rheumatoid* ; Citrulline*

BACKGROUND: The Rheumatoid Factor (RF) is the only serological marker in the diagnosis of rheumatoid arthritis (RA), but its sensitivity and specificity are not satisfactory for the diagnosis of RA. Therefore, we investigated the diagnostic performance of a new anti-cyclic citrullinated peptide antibodies test (anti-CCP) by the enzyme-linked immunosorbent assay (ELISA) in RA. METHODS: A cyclic peptide variant that contains citrulline was used as an antigenic substrate in ELISA. We performed the RF and anti-CCP in 324 RA patients, 251 non-RA patients (rheumatic diseases other than RA), and 286 normal individuals. Diagnostic performances such as sensitivity and specificity were evaluated by the receiver-operator characteristics (ROC) curve at optimal cut-off values. The optimal cut-off values were determined at the maximal point of the area under the curve. RESULTS: The sensitivity and specificity of anti-CCP were 72.8% and 92% at 3.8 U/mL. The sensitivity and specificity of RF were 80.6% and 78.5% at 9 U/mL. The sensitivity and specificity of anti-CCP and RF were 67%, 95.2% and 63.3%, 90% at 8.4 U/mL, 20 U/mL, respectively. A combination of anti-CCP with RF increased the sensitivity and specificity to 79.3%, 96.4%, respectively. Anti-CCP was positive in 23.8% among 63 sero-negative RA patients. CONCLUSIONS: We considered that the anti-CCP might be useful as another new serological marker for the diagnosis of a RA combination with RF, or not, because the anti-CCP has a higher diagnostic specificity than the RF and was an easy, convenient ELISA method in performance.
Antibodies* ; Arthritis, Rheumatoid* ; Citrulline ; Diagnosis ; Enzyme-Linked Immunosorbent Assay ; Humans ; Rheumatoid Factor ; Sensitivity and Specificity

A deficiency of the urea cycle enzyme, argininosuccinate synthetase which is produced in liver, makes citrullinemia, which is an autosomal recessive disorder. As the liver is the only organ which transforms ammonia into urea, liver transplantation has been considered as an effective alternative therapy to classical dietary and medical therapy. We have experienced perioperative anesthetic care for a 27-year-old male with citrullinemia undergoing successful living donor auxiliary partial orthotopic liver transplantation (APOLT). After the liver transplantation, the postoperative clinical courses of the patient were uneventful, and the neurological symptoms were completely resolved. The plasma concentrations of ammonia and citrulline normalized rapidly without any kinds of protein dietary restrictions. We present this case with a brief review of literature.
Adult ; Ammonia ; Argininosuccinate Synthase ; Citrulline ; Citrullinemia ; Humans ; Hyperammonemia ; Liver ; Liver Transplantation ; Living Donors ; Male ; Plasma ; Urea

Citrullinemia type I is an urea cycle defect caused by mutations in the argininosuccinate synthetase (ASS1) gene. We report a novel argininosuccinate synthetase gene mutation in a Korean family with type I citrullinemia. Metabolic evaluation revealed significant hyperammonemia. Amino acid/acylcarnitine screening using tandem mass spectrometry showed high level of citrulline. Plasma amino acid analysis showed high level of citrulline and the urine organic acid analysis showed makedly increased level of orotic acid. To confirm diagnosis of citrullinemia we did mutation analysis of the ASS1 gene. The patient was found to have mutations of c.689G>C (p.G230A) and c.892G>A (p.E298K), which were new types of argininosuccinate synthetase gene mutation have never been reported in Korea. We report a novel case of argininosuccinate synthetase 1 gene mutation and suggest that the gene study to the family members is necessary to carry out when a patient is diagnosed as citrullinemia.
Argininosuccinate Synthase ; Citrulline ; Citrullinemia ; Humans ; Hyperammonemia ; Korea ; Mass Screening ; Orotic Acid ; Plasma ; Tandem Mass Spectrometry ; Urea

Citrullinemia type I is an urea cycle defect caused by mutations in the argininosuccinate synthetase (ASS1) gene. We report a novel argininosuccinate synthetase gene mutation in a Korean family with type I citrullinemia. Metabolic evaluation revealed significant hyperammonemia. Amino acid/acylcarnitine screening using tandem mass spectrometry showed high level of citrulline. Plasma amino acid analysis showed high level of citrulline and the urine organic acid analysis showed makedly increased level of orotic acid. To confirm diagnosis of citrullinemia we did mutation analysis of the ASS1 gene. The patient was found to have mutations of c.689G>C (p.G230A) and c.892G>A (p.E298K), which were new types of argininosuccinate synthetase gene mutation have never been reported in Korea. We report a novel case of argininosuccinate synthetase 1 gene mutation and suggest that the gene study to the family members is necessary to carry out when a patient is diagnosed as citrullinemia.
Argininosuccinate Synthase ; Citrulline ; Citrullinemia ; Humans ; Hyperammonemia ; Korea ; Mass Screening ; Orotic Acid ; Plasma ; Tandem Mass Spectrometry ; Urea

OBJECTIVEThe conversion of arginine into citrulline, termed citrullination, has important consequences for the structure and function of proteins. The present study aimed to identify novel citrullinated proteins in 10 tumor cell lines by 2-D Western blotting (2-D WB).

METHODSTwo identical two-dimensional electrophoresis (2-DE) gels were prepared using extracts from ten cultured human tumor cell lines: ECA(esophageal cancer cells), HEPG2 (hepatocellular carcinoma cells), SKOV3 (ovarian cancer cells), MCF-7 (breast cancer cells), H292 (lung mucoepidermoid carcinoma cells), HeLa (cervical cancer cells), Lovo (colon cancer cells), OS-RC (renal cell carcinoma cells), PANC-1 (pancreatic cancer cells), and SGC (gastric cancer cells). The expression profiles on one 2-DE gels were trans-blotted to PVDF membranes, and the blots were then probed with an anti-citrulline antibody. By comparing the 2-DE profile with the parallel 2-D WB profile at a global level, protein spots with immuno-signals were collected from the second 2-DE gel and identified using mass spectrometry. Immunoprecipitation was used to verify the expression and citrullination of the targeted proteins in the tumor cell lines.

RESULTS2-D WB and mass spectrometry identified citrullinated ENO1 (α-enolase), HSP60 (heat shock protein 60), KRT8 (keratin 8), TUBB (tubulin beta), TCRβ (T cell receptor β chain), VIME (vimentin) and PDI in these cell lines. Immunoprecipitation analyses verified the expression and citrullination of ENO1, HSP60, KRT8, and TUBB in the total protein lysates of the tumor cell lines.

CONCLUSIONThe citrullination of proteins ENO1, HSP60, KRT8, and TUBB suggests a new mechanism in the tumorigenic process.

Blotting, Western ; Cell Line, Tumor ; Citrulline ; metabolism ; Female ; Humans ; Immunoprecipitation ; Mass Spectrometry ; Phosphopyruvate Hydratase ; Vimentin

OBJECTIVE: To investigate the expression of citrullinated epitopes in articular cartilage protein and whether its expression is sufficient to induce anti-citrullinated protein antibody (ACPA) response in mice. METHODS: The experimental group was treated with different concentrations of lipopolysaccharide (LPS), heat-inactivated bacteria ( and ) or specific monoclonal antibody against type Ⅱ collagen to induce citrullination of articular cartilage protein, with PBS as the control. Immunohistochemistry with the monoclonal antibody ACC4 (IgG1) that specifically binds to the citrullinated epitope of cartilage protein was performed for detecting the expression of citrullinated protein, with ACC1 (IgG2a) as a positive control antibody and L243 (IgG2a) and Hy2.15 (IgG1) as the negative isotype control. In the in vivo experiment, SD rats were subjected to injection of different doses of LPS in the right knee (with PBS as the controls in the left knee), and 3 days later frozen sections were prepared for immunohistochemical detection of the expression of citrullinated protein. Models of collagen-induced arthritis (CIA) established in different mouse strains were observed for incidence and severity of CIA. Serum samples collected from these models and the sera from rheumatoid arthritis patients were examined for anti-citrullinated protein antibody, and immunohistochemistry was performed to detect the expression of citrullinated protein in the cartilage of the mouse. RESULTS: The citrullinated CII epitope-specific antibody ACC4 did not bind to articular cartilage tissues with different treatments as compared with the positive control antibody ACC1. The ACC4 antibody and the antibodies from patients with rheumatoid arthritis with high titers of anti-citrullinated protein antibody were capable of binding to the synovial tissue around the articular cartilage of the CIA. Luminex analysis showed that the anti-citrullinated protein antibody was lowly expressed in mouse serum, but the anti-type Ⅱ collagen triple helix structure peptide antibody exhibited strong reactivity. CONCLUSIONS Mild acute inflammatory response is not enough to cause citrullination of articular cartilage protein, and the expression of specific epitope requires a high-intensity inflammatory response. Inflammatory articular cartilage protein can express citrullinated epitopes in type Ⅱ collagen-induced arthritis in mice, but the expression of citrullinated epitopes is not sufficient to induce an immune response to anti-citrullinated antibodies. Stronger stimulation signals are required to induce an immune response for producing anti-citrullinated protein antibodies.
Animals ; Arthritis, Experimental ; Autoantibodies ; Cartilage, Articular ; Citrulline ; Humans ; Inflammation ; Mice ; Rats ; Rats, Sprague-Dawley

The male neonate in this case study was admitted to the hospital at 15 hours of age due to respiratory distress for 15 hours and poor response for 3 hours after resuscitation from asphyxia. The neonate was highly unresponsive, with central respiratory failure and seizures. Serum ammonia was elevated (>1 000 μmol/L). Blood tandem mass spectrometry revealed a significant decrease in citrulline. Rapid familial whole genome sequencing revealed OTC gene mutations inherited from the mother. Continuous hemodialysis filtration and other treatments were given. Neurological assessment was performed by cranial magnetic resonance imaging and electroencephalogram. The neonate was diagnosed with ornithine transcarbamylase deficiency combined with brain injury. He died at 6 days of age after withdrawing care. This article focuses on the differential diagnosis of neonatal hyperammonemia and introduces the multidisciplinary management of inborn error of metabolism.
Humans ; Infant, Newborn ; Male ; Citrulline ; Electroencephalography ; Hyperammonemia ; Ornithine Carbamoyltransferase Deficiency Disease/therapy* ; Seizures

OBJECTIVE: To investigate whether dynamic monitoring of citrulline (Cit) has guiding value for early enteral nutrition (EN) in patients with severe gastrointestinal injury. METHODS: A observational study was conducted. A total of 76 patients with severe gastrointestinal injury admitted to different intensive care units of Suzhou Hospital Affiliated to Nanjing Medical University from February 2021 to June 2022 were enrolled. Early EN was performed in 24-48 hours after admission as recommended by the guidelines. Those who did not terminate EN after 7 days were enrolled in the early EN success group, and those who terminated EN within 7 days due to persistent feeding intolerance or deterioration of general condition were enrolled in the early EN failure group. There was no intervention during the treatment. Serum Cit levels were measured by mass spectrometry at admission, before EN starting and EN 24 hours, respectively, and the changes in Cit within EN 24 hours (ΔCit) were calculated (ΔCit = EN 24-hour Cit-Cit before EN starting). Receiver operator characteristic curve (ROC curve) was plotted to investigate the predictive value of ΔCit for early EN failure, and the optimal predictive value was calculated. Multivariate unconditional Logistic regression was used to analyze the independent risk factors for early EN failure and death at 28 days. RESULTS: Seventy-six patients were enrolled in the final analysis, of which 40 succeeded in early EN and 36 failed. There were significant differences in age, main diagnosis, acute physiology and chronic health evaluation II (APACHE II) score at admission, blood lactic acid (Lac) before EN initiation and ΔCit between the two groups. Multivariate Logistic regression analysis showed that age [odds ratio (OR) = 0.929, 95% confidence interval (95%CI) was 0.874-0.988, P = 0.018], ΔCit (OR = 2.026, 95%CI was 1.322-3.114, P = 0.001) and increased feeding rate within 48 hours (OR = 13.719, 95%CI was 1.795-104.851, P = 0.012) were independent risk factors for early EN failure in patients with severe gastrointestinal injury. ROC curve analysis showed that ΔCit had a good predictive value for early EN failure in patients with severe gastrointestinal injury [area under the ROC curve (AUC) = 0.787, 95%CI was 0.686-0.887, P < 0.001], and the optimal predictive value of ΔCit was 0.74 μmol/L (sensitivity was 65.0%, specificity was 75.0%). Combined with the optimal predictive value of ΔCit, "overfeeding" was defined as ΔCit < 0.74 μmol/L and increased feeding within 48 hours. Multivariate Logistic regression analysis showed that age (OR = 0.825, 95%CI was 0.732-0.930, P = 0.002), APACHE II score (OR = 0.696, 95%CI was 0.518-0.936, P = 0.017) and early EN failure (OR = 181.803, 95%CI was 3.916-8 439.606, P = 0.008) were independent risk factors for 28-day death in patients with severe gastrointestinal injury. The new variable "overfeeding" was also associated with an increased risk of death at 28 days (OR = 27.816, 95%CI was 1.023-755.996, P = 0.048). CONCLUSIONS Dynamic monitoring of Cit has guiding value for early EN in patients with severe gastrointestinal injury.
Humans ; Infant, Newborn ; Enteral Nutrition ; Citrulline ; APACHE ; Abdominal Injuries ; Cognition ; Thoracic Injuries

The multiple post-translational modifications of proteins display specific gain- or loss-of-function under normal and abnormal conditions. These modifications are precisely regulated by post-translational modification enzymes. The altered molecular status perturbs the pattern of gene expression and decides on a direction to signal transduction cascades as well as intrinsic properties of the proteins. Ultimately, it strictly maintains intracellular environment or results in disease manifestations. Recently, it has become that enzyme-dependent modification of arginine residue to citrulline exerts an important role in the induction of autoimmunity including rheumatoid arthritis, multiple sclerosis, and cancer. The modification of arginine residue to citrulline on proteins is called 'citrullination' or 'deimination' and is regulated by the calcium-dependent enzyme peptidylarginine deiminase (PAD). Now many effective PAD inhibitors (for example, Cl-amidine) have developed that ameliorates disease phenotypes. In this review, we discuss crucial roles of PAD enzyme and citrullination, the effectiveness of PAD inhibitors, and the implication in pathology.
Arginine ; Arthritis, Rheumatoid ; Autoimmunity ; Citrulline ; Gene Expression ; Hydrolases ; Multiple Sclerosis ; Ornithine ; Phenotype ; Protein Processing, Post-Translational ; Proteins ; Signal Transduction