Biomarkers for radiation-induced small bowel epithelial damage:An emerging role for plasma Citrulline

Reduction of cancer treatment-induced mucosal injury has been recognized as an important target for improving the therapeutic ratio as well as reducing the economic burden associated with these treatment related sequellae. Clinical studies addressing this issue are hampered by the fact that specif ic objective parameters, which enable monitoring of damage in routine clinical practice, are lacking. This review summarizes pros and cons of currently available endpoints for intestinal injury. The metabolic background and characteristics of plasma citrulline, a recently investigated biomarker specifically for small intestinal injury, are discussed in more detail.

Effects of arginine replacement with L-citrulline on the arginine/nitric oxide metabolism in chickens:An animal model without urea cycle

Background This study examined the efficacy of L-citrulline supplementation on the arginine/nitric oxide metabolism,and intestinal functions of broilers during arginine deficiency.A total of 288 day-old Arbor Acre broilers were randomly assigned to either an arginine deficient basal diet(NC diet),NC diet+0.50%L-arginine(PC diet),or NC diet+0.50%L-citrulline(NCL diet).Production performance was recorded,and at 21 days old,chickens were euthanized for tissue collection.Results The dietary treatments did not affect the growth performance of broilers(P>0.05),although NC diet increased the plasma alanine aminotransferase,urate,and several amino acids,except arginine(P<0.05).In contrast,NCL diet elevated the arginine and ornithine concentration higher than NC diet,and it increased the plasma citrulline greater than the PC diet(P<0.05).The nitric oxide concentration in the kidney and liver tissues,along with the plasma and liver e NOS activities were promoted by NCL diet higher than PC diet(P<0.05).In the liver,the activities of arginase 1,ASS,and ASL,as well as,the gene expression of i NOS and OTC were induced by PC diet greater than NC diet(P<0.05).In the kidney,the arginase 1,ASS and ASL enzymes were also increased by PC diet significantly higher than the NC and NCL diets.Comparatively,the kidney had higher abundance of n NOS,ASS,ARG2,and OTC genes than the liver tissue(P<0.05).In addition,NCL diet upregulated(P<0.05)the m RNA expression of intestinal nutrient transporters(EAAT3 and PEPT1),tight junction proteins(Claudin 1 and Occludin),and intestinal mucosal defense(MUC2 and p Ig R).The intestinal morphology revealed that both PC and NCL diets improved(P<0.05)the ileal VH/CD ratio and the jejunal VH and VH/CD ratio compared to the NC fed broilers.Conclusion This study revealed that NCL diet supported arginine metabolism,nitric oxide synthesis,and promoted the intestinal function of broilers.Thus,L-citrulline may serve as a partial arginine replacement in broiler’s diet without detrimental impacts on the performance,arginine metabolism and gut health of chickens.

Plasma Citrulline Concentrations in Neonates and Infants with or without Gastrointestinal Disease and Bowel Resection

Various studies have shown a role for citrulline as a gut mass biomarker in patients with short bowel syndrome. Our hypothesis is that plasma citrulline is both a gastrointestinal (GI) function and a gut mass marker. Our objective was to validate previous observations, by prospectively analyzing plasma citrulline concentrations in patients with GI disease with or without bowel resection, compared to patients without GI disease. Plasma from blood samples of parenteral nutrition fed neonates and infants was obtained. Samples were analyzed by ion-exchange chromatography. Data collected included age, diagnoses and surgical documentation of bowel resection. Patients were classified into 3 main groups: those without GI disease nor resection (Group 1), those with GI disease but no resection (Group 2), and those with GI disease and resection (Group 3). Group medians were compared using Kruskal-Wallis ANOVA. Seventeen samples were evaluated. Patients in Group 3 were older compared to patients in Groups 1 and 2;median age (in days) 156 vs. 12 vs. 57 respectively. Median (range) plasma citrulline concentrations were 20.9 (14.9 - 29.0) μmol/L, 8.7 (0.5 - 20.0) μmol/L and 9.6 (5.9 - 13.2) μmol/L for Groups 1, 2 and 3 respectively. There were significant differences among medians and sample distributions between Groups 1 and 2 and between 1 and 3 (p < 0.05). No differences were observed between Groups 2 and 3. Patients without GI disease and no resection had significantly higher plasma citrulline concentrations than patients with GI disease with or without resection at the time of assessment.

Plasma Citrulline: A New Marker of Gut Epithelium Alteration in Obese Patients?

Objectives: In the last decade gut microbial diversity was associated with the pathogenesis of obesity in humans. Plasma citrulline was a simple and accurate biomarker for the severity of intestinal failure and was associated with short bowel syndrome and alteration of gut permeability, being developed as an alternative to D-xylose tolerance test for the diagnosis of an abnormal small intestinal absorption of nutrients. This study was performed to ascertain whether obesity might be associated with dysregulation of epithelial gut function. Methods: Fifteen obese individuals (5 M/10 F;BMI 37.4 ± 6.1 Kg/m2;42 ± 6 yrs) and 15 healthy gender- and age-matched controls (6 M/9 F BMI: 22.7 ± 2.1 Kg/m2;39 ± 7 yrs) underwent D-xylose load (25 g) and plasma citrulline, plasma insulin, glucose and lipid profile testing. Results: Plasma citrulline was significantly lower in the obese group (p = 0.045) with respect to controls, whilst total cholesterol, LDL and trygliceri- des concentration, insulin level and HOMA-IR were significantly higher in obese patients. In contrast, after D-xylose load no difference in serum xylose was found between the two groups (p = ns). Conclusions: Obese patients show a decreased citrulline concentration with respect to lean subjects. Since citrulline is a known marker of intestinal health, alterations in the gut epithelium are likely to be associated with the obesity syndrome. We propose to measure citrulline level in obese patients on a routine basis.

Response of laying hens to L-arginine,L-citrulline and guanidinoacetic acid supplementation in reduced protein diet

A study was conducted with Hy-Line Brown laying hens to examine the effects of reduced protein diet,deficiency of arginine(Arg),and addition of crystalline Arg,citrulline(Cit)and guanidinoacetic acid(GAA)as substitutes for Arg.Hen performance,egg quality,serum uric acid,liver and reproductive organ weights,and energy and protein digestibility were measured using a completely randomized design with 5 treatments.Treatments were a standard diet(17%protein diet;SP),a reduced diet(13%protein diet deficient in Arg;RP)and RP with added Arg(0.35%,RP-Arg),GAA(0.46%equivalent to 0.35%Arg,RP-GAA)or Cit(0.35%,RP-Cit)to the level of SP.It was hypothesized that performance would decrease with Arg deficient RP diet and the addition of GAA or Cit in RP would allow birds to perform similar or greater than Arg-added RP treatment.The experiment was conducted from 20 to 39 wk of age but the treatment effect was seen only after 29 wk of age.The birds offered RP had reduced egg and albumin weights(P<0.01),lower yolk color score(P<0.01),lower protein intake and excretion(P<0.01)than those offered SP.When Arg or Cit were added to RP to make them equivalent to SP,feed intake(FI)and egg production were not different than those of RP(P>0.05).The birds offered RP-GAA decreased FI and egg production(P<0.01)compared to those offered RP.The addition ofArg,Cit or GAA to the RP had no effect on egg quality parameters,protein and energy digestibilities(P>0.05).However,birds offered the RP-Cit diet tended to have higher Haugh unit(P=0.095)and lower shell breaking strength(P=0.088)compared to all other treatments while those offered RP-GAA had higher energy digestibility(P<0.05)than all other groups but RP.The limited performance response of hens fed RP with added Arg,GAA,or Cit may be due to deficiency of some other nutrients in RP such as phenylalanine,potassium or non-essential amino acids and other components of soybean meal in the diet.

Effects of L-arginine and L-citrulline supplementation in reduced protein diets for broilers under normal and cyclic warm temperature

Heat stress causes significant economic losses in the broiler industry.Dietary supplementation of arginine(Arg)and citrulline(Cit)might increase the performance of broilers raised under warm temperature due to vasodilation effects.This study investigated the effects of L-Arg or L-Cit supplementation in broilers fed a reduced protein wheat-based diet deficient in Arg under thermoneutral(NT)and cyclic warm temperature(WT).Ross 308 cockerels(n=720)were randomly allocated to 4 dietary treatments with 12 replicates of 15 birds per pen from d 7 to 21.The 4 treatments were:normal protein(NP),i.e.,22.3%and 20.9%crude protein in grower and finisher,respectively;reduced protein(RP),i.e.,2.5%lower protein and deficient in Arg;and RP supplemented with 0.28%Arg(RP-Arg)or 0.28%Cit(RP-Cit).A factorial arrangement of treatments was applied during the finisher phase(21 to 35 d).Factors were:diet(4 diets above);and temperature,NT(24℃)or cyclic WT(33±1℃for 6 h per day)with 6 replicate pens per treatment.During 7 to 35 d and 21 to 35 d,the birds fed the RP diet had lower body weight gain(BWG)and higher FCR compared to the NP diet(P<0.01).The addition of Arg or Cit to RP decreased FCR compared to RP(P<0.01).During 21 to 35 d,the birds exposed to WT had lower feed intake(FI),lower BWG(P<0.001)but similar FCR(P>0.05)compared to birds exposed to NT.Diet by temperature interactions were not observed for performance parameters during the period of WT(P>0.05).On d 35,the RP-fed birds had a lower yield of thigh and drumstick,higher fat pad,lower femur ash,and breaking strength but similar serum uric acid level and higher nitrogen digestibility on d 21 compared to those offered NP(P<0.05).Supplementation of Arg or Cit to RP resulted in increased femur ash on d 35(P<0.05).Thus,feeding the NP diets is necessary to maintain growth performance in broilers regardless of the temperature conditions.

Diagnostic value of digital continuous bowel sounds in critically ill patients with acute gastrointestinal injury: A prospective observational study

BACKGROUND Acute gastrointestinal injury(AGI)is common in intensive care unit(ICU)and worsens the prognosis of critically ill patients.The four-point grading system proposed by the European Society of Intensive Care Medicine is subjective and lacks specificity.Therefore,a more objective method is required to evaluate and determine the grade of gastrointestinal dysfunction in this patient population.Digital continuous monitoring of bowel sounds and some biomarkers can change in gastrointestinal injuries.We aimed to develop a model of AGI using continuous monitoring of bowel sounds and biomarkers.AIM To develop a model to discriminate AGI by monitoring bowel sounds and biomarker indicators.METHODS We conducted a prospective observational study with 75 patients in an ICU of a tertiary-care hospital to create a diagnostic model for AGI.We recorded their bowel sounds,assessed AGI grading,collected clinical data,and measured biomarkers.We evaluated the model using misjudgment probability and leave-one-out cross-validation.RESULTS Mean bowel sound rate and citrulline level are independent risk factors for AGI.Gastrin was identified as a risk factor for the severity of AGI.Other factors that correlated with AGI include mean bowel sound rate,amplitude,interval time,Sequential Organ Failure Assessment score,Acute Physiology and Chronic Health Evaluation II score,platelet count,total protein level,blood gas potential of hydrogen(pH),and bicarbonate(HCO3-)level.Two discriminant models were constructed with a misclassification probability of<0.1.Leave-one-out cross-validation correctly classified 69.8%of the cases.CONCLUSION Our AGI diagnostic model represents a potentially effective approach for clinical AGI grading and holds promise as an objective diagnostic standard for AGI.

Human small intestine is capable of restoring barrier function after short ischemic periods

AIM To assess intestinal barrier function during human intestinal ischemia and reperfusion(IR).METHODS In a human experimental model,6 cm of jejunum was selectively exposed to 30 min of ischemia(I) followed by 30 and 120 min of reperfusion(R). A sham procedure was also performed. Blood and tissue was sampled at all-time points. Functional barrier function was assessed using dual-sugar absorption tests with lactulose(L) and rhamnose(R). Plasma concentrations of citrulline,an amino acid described as marker for enterocyte function were measured as marker of metabolic enterocytes restoration. Damage to the epithelial lining was assessed by immunohistochemistry for tight junctions( TJs),by plasma marker for enterocytes damage(I-FABP) and analyzed by electron microscopy(EM) using lanthanum nitrate as an electrondense marker.RESULTS Plasma L/R ratio's were significantly increased after 30 min of ischemia(30 I) followed by 30 min of reperfusion(30 R) compared to control(0.75 ± 0.10 vs 0.20 ± 0.09,P < 0.05). At 120 min of reperfusion(120 R),ratio's normalized(0.17 ± 0.06) and were not significantly different from control. Plasma levels of I-FABP correlated with plasma L/R ratios measured at the same time points(correlation: 0.467,P < 0.01). TJs staining shows distortion of staining at 30 I. An intact lining of TJs was again observed at 30 I120 R. Electron microscopy analysis revealed disrupted TJs after 30 I with paracellular leakage of lanthanum nitrate,which restored after 30 I120 R. Furthermore,citrulline concentrations closely paralleled the histological perturbations during intestinal IR.CONCLUSION This study directly correlates histological data with intestinal permeability tests,revealing that the human gut has the ability of to withstand short episodes of ischemia,with morphological and functional recovery of the intestinal barrier within 120 min of reperfusion.

Biomarkers in inflammatory bowel diseases:Current status and proteomics identification strategies

Unambiguous diagnosis of the two main forms of inflammatory bowel diseases (IBD): Ulcerative colitis (UC) and Crohn&#x02019;s disease (CD), represents a challenge in the early stages of the diseases. The diagnosis may be established several years after the debut of symptoms. Hence, protein biomarkers for early and accurate diagnostic could help clinicians improve treatment of the individual patients. Moreover, the biomarkers could aid physicians to predict disease courses and in this way, identify patients in need of intensive treatment. Patients with low risk of disease flares may avoid treatment with medications with the concomitant risk of adverse events. In addition, identification of disease and course specific biomarker profiles can be used to identify biological pathways involved in the disease development and treatment. Knowledge of disease mechanisms in general can lead to improved future development of preventive and treatment strategies. Thus, the clinical use of a panel of biomarkers represents a diagnostic and prognostic tool of potentially great value. The technological development in recent years within proteomic research (determination and quantification of the complete protein content) has made the discovery of novel biomarkers feasible. Several IBD-associated protein biomarkers are known, but none have been successfully implemented in daily use to distinguish CD and UC patients. The intestinal tissue remains an obvious place to search for novel biomarkers, which blood, urine or stool later can be screened for. When considering the protein complexity encountered in intestinal biopsy-samples and the recent development within the field of mass spectrometry driven quantitative proteomics, a more thorough and accurate biomarker discovery endeavor could today be performed than ever before. In this review, we report the current status of the proteomics IBD biomarkers and discuss various emerging proteomic strategies for identifying and characterizing novel biomarkers, as well as suggesting future targets for analysis.

Peptidylarginine deiminases and extracellular vesicles: prospective drug targets and biomarkers in central nervous system diseases and repair

Peptidylarginine deiminases are a family of calcium-activated enzymes with multifaceted roles in physiological and pathological processes,including in the central nervous system.Peptidylarginine deiminases cause post-translational deimination/citrullination,leading to changes in structure and function of a wide range of target proteins.Deimination can facilitate protein moonlighting,modify protein-protein interaction,cause protein dysfunction and induce inflammatory responses.Peptidylarginine deiminases also regulate the biogenesis of extracellular vesicles,which play important roles in cellular communication through transfer of extracellular vesicle-cargo,e.g.,proteins and genetic material.Both peptidylarginine deiminases and extracellular vesicles are linked to a number of pathologies,including in the central nervous system,and their modulation with pharmacological peptidylarginine deiminase inhibitors have shown great promise in several in vitro and in vivo central nervous system disease models.Furthermore,extracellular vesicles derived from mesenchymal stem cells have been assessed for their therapeutic application in central nervous system injury.As circulating extracellular vesicles can be used as non-invasive liquid biopsies,their specific cargo-signatures(including deiminated proteins and microRNAs)may allow for disease“fingerprinting”and aid early central nervous system disease diagnosis,inform disease progression and response to therapy.This mini-review discusses recent advances in the field of peptidylarginine deiminase and extracellular vesicle research in the central nervous system,focusing on several central nervous system acute injury,degeneration and cancer models.

Increased IgG Rheumatoid Factor-Positivity in the Asian Rheumatoid Arthritis Patients Irrespective of Ethnicity

Aim of Work: Initial observations implied IgG rheumatoid factor (RF) to be common among Malaysian rheumatoid arthritis (RA) patients. We tested this hypothesis and used a multiethnic RA cohort (Malays, Chinese and Indians) to investigate whether the IgG RF predominance might be genetically or environmentally determined. Patients and Methods: 556 serum samples comprising 171 patients classified as RA according to the 1987 ACR criteria, 60 patients with other rheumatic diseases and 325 non-rheumatic controls were tested for IgG RF, IgM RF and anti-CCP by ELISA. The findings were then tested in a larger RA case-control cohort (n = 1844). Results: IgG RF predominated over IgM RF in all the investigated ethnic groups. The sensitivity, specificity, and diagnostic accuracy of IgG RF (55.6%, 91.2% and 80.2%, respectively) were superior compared to IgM RF, but comparable to anti-CCP. IgG RF was however, also increased in the Malaysian controls, but the IgG RF superiority over IgM RF was still apparent after cutoff adjustment according to the 1987 ACR criteria. Autoantibody levels did not differ between the three ethnic groups. The Receiver Operating Characteristics (ROC) curves showed larger areas under the curves for IgG RF (0.826) and for anti-CCP (0.867) than for IgM RF (0.737). Review of the literature showed consistently higher sensitivity for IgG RF in studies of Asian RA patients as compared to Caucasian and African-American studies. Conclusion: Increased frequency of IgG RF-positive in RA populations with different genetic background living in Malaysia argues for an environmental factor selectively amplifying the IgG RF response.

Does a biological link exist between periodontitis and rheumatoid arthritis?

Periodontitis or Periodontal disease(PD) and Rheumatoid arthritis(RA) are two the most common chronic inflammatory diseases. Periodontitis is a biofilm associated destructive inflammatory disease of the periodontium caused by specific microorganisms. Rheumatoid arthritis is an autoimmune condition and is identified by elevated serum autoantibody titre directed against citrullinated peptides or rheumatoid factor. Periodontitis may involve some elements of autoimmunity. Recent studies have established that PD and RA show a common pathway and could be closely associated through a common dysregulation and dysfunction in inflammatory mechanism. The enzyme peptidyl arginine deiminase(PAD), expressed by Porphyromonas gingivalis(P. gingivalis) is responsible for the enzymatic deimination of arginine residuals to citrulline resulting in protein citrullination and its increased accumulation in RA.Citrullination by PAD may act as a putative biologic link between PD and RA. Association of Human leukocytic antigen-DR4 antigen has been established both with RA and PD. Several interleukins and inflammatory mediators(ILs) and Nuclear factor kappa beta ligand are linked to these common chronic inflammatory diseases. Antibodies directed against heat shock protein(hsp 70 ab) of P. gingivalis, P. melanogenicus and P. intermedia are raised in PD as well as RA. Both the conditions share many pathological and immunological similarities. Bacterial infection, genetic susceptibility, altered immune reaction and inflammatory mediators considered responsible for RA are also associated with PD. So it is plausible that a biological link may exist between PD and RA. Therapies aimed at modifying the expression and effect of inflammatory mediators and effector molecules such as matrix metalloproteinases, proinflammatory cytokines and autoantibodies of structural proteins may probably reduce the severity of both RA and PD.

Diagnostic Value of Antibodies against a Modified Citrullinated Vimentin in Rheumatoid Arthritis

Aim of Work: To investigate the value of the detection of antibodies against modified citrullinated vimentin antibodies (anti-MCV) in comparison with anti-CCP2-for the diagnosis of rheumatoid arthritis (RA). Patients and Methods: The study Included Forty patients with Rheumatoid arthritis (RA). They under went assessment by the disease activity score (DAS-28), visual analogue scale (VAS) and health assessment questionnaire (HAQ). Thirty healthy subjects matched for age and sex served as a control group. Blood samples were obtained from patients and controls for erythrocyte sedimentation rate (ESR), C reactive protein (CRP), rheumatoid factor (RF). Anti-CCP2 and anti-MCV were determined using ELISA technique. Results: Estimated serum levels of anti-CCP2 and anti-MCV were significantly higher in patients compared to controls (p 0.001). There were no significant correlations between anti-MCV levels and age, dis- ease duration, duration of morning stiffness, number of swollen and tender joints, HAQ or ESR in patients with RA, while serum levels correlates significantly with DAS28, VAS and CRP (p 0.05). Anti-CCP2 correlates significantly with DAS28, VAS and CRP and ANA (p 0.05). Serum anti-MCV and anti-CCP2 were significantly correlated with each other (r = 0.483;p The receiver operating characteristic (ROC) curve was drawn and it showed that anti-MCV had diagnostic specificity, sensitivity of 93.3%, 75.5%, respectively, while anti-CCP2 specificity, sensitivity of 98.1%, 85%, respectively. Conclusion: Serum anti-MCV as well as the anti-CCP-2 assay perform comparably well in the diagnosis of RA. In the high-specificity range, however, the anti-CCP2 assay appears to be superior to the anti-MCV test.

Challenges of Rheumatoid Arthritis Management in Sub-Saharan Africa in the 21st Century

In recent decades, several advances have been made in the management of rheumatoid arthritis (RA) both in the diagnostic field and in the therapeutic field. Unfortunately, RA remains poorly studied in black Africa. Epidemiological data are rare and controversial. The estimated prevalence of RA in Africa is about 0% - 2.54%. Risk factors associated with RA must be studied by taking into account special features of black Africa such as the low tobacco consumption in certain regions, the tropical climate and the high frequency of endemic parasitic and viral infections. The initially supposed mildness of RA in black Africa is increasingly challenged. The diagnosis is often made too late because of the scarcity of rheumatologists and ignorance. Diagnostic tools are limited to the clinical data, the erythrocyte sedimentation rate and radiographs as the other tools are poorly available. In addition, there are misconceptions in African communities, responsible for loss of sight during follow-up and treatment discontinuations. This is exacerbated by the shortage of disease-modifying anti-rheumatic drugs (DMARDs) and the inability to afford them. Furthermore, biological agents are very difficult to access. Further studies are essential to better understand the characteristics of RA in black Africa. Thus, collaborations between African and Western research teams seem very important. In order to make available the DMARDs especially biological agents, pharmaceutical companies can contribute through research partnerships. Moreover, governments should provide a better place for chronic inflammatory diseases in the programs against non-communicable diseases. Finally, training must also be promoted to increase the number of specialists and the level of knowledge of other health workers.

Psoriatic arthritis: clinical patterns, rheumatoid factor, anti-cyclic citrullinated peptide and human leukocyte antigen risk alleles

Psoriatic arthritis is an inflammatory arthritis associated with psoriasis.Both rheumatoid factor and anti-cyclic citrullinated peptide antibodies positive psoriatic arthritis patients may be in risk for development of symmetrical polyarthritis pattern.Symmetrical polyarthritis pattern was predominant(42%)among clinical pattern of psoriatic arthritis.Among 10 rheumatoid factor positive patients,8(80%)patients had symmetrical polyarthritis pattern and out of 7 anti-cyclic citrullinated peptide antibody positive patients,7(100%)patients had symmetrical polyarthritis pattern.Association of anti-cyclic citrullinated peptide(P=0.008)and rheumatoid factor(P=0.006)showed statistical significance with symmetrical polyarthritis pattern.Human leukocyte antigen-B*07,*38 and human leukocyte antigen-C*07 were predominantly found in rheumatoid factor and anti-cyclic citrullinated peptide positive psoriatic arthritis patients.Background:Psoriatic arthritis is an inflammatory arthritis associated with psoriasis.It is usually seronegative in nature but a small percentage of patients may be positive for rheumatoid factor and anti-cyclic citrullinated peptide antibodies.Anti-cyclic citrullinated peptide and rheumatoid factor are highly specific for rheumatoid arthritis but their role is not clear in psoriatic arthritis.The prevalence and prognostic value of anti-cyclic citrullinated peptide antibody and rheumatoid factor in psoriatic arthritis patients is not well known.The aim of this study was therefore to investigate the prevalence of anti-cyclic citrullinated peptide antibodies and rheumatoid factor in psoriatic arthritis patients and assess their clinical associations and also to see the distribution of human leukocyte antigen-B and human leukocyte antigen-C locus antigens in anti-cyclic citrullinated peptide antibody and rheumatoid factor positive psoriatic arthritis patients.Methods:Fifty patients with psoriatic arthritis were tested for the presence of rheumatoid factor and anti-cyclic citrullinated peptide antibodies.Polymerase chain reaction was done with sequence specific primer for detection of human leukocyte antigen-B and human leukocyte antigen-C locus antigens in rheumatoid factor and anti-cyclic citrullinated peptide positive psoriatic arthritis patients.Data on five clinical patterns of rheumatological manifestations of psoriatic arthritis patients were collected prospectively on all patients and statistically compared between anti-cyclic citrullinated peptide,rheumatoid factor positive and negative patients by chi-square test.We also see the distribution of human leukocyte antigen-B and human leukocyte antigen-C locus antigens in anti-cyclic citrullinated peptide antibody and rheumatoid factor positive psoriatic arthritis patients.Results:Among 50 psoriatic arthritis patients,rheumatoid arthritis test was positive in 10(20%)patients and anti-cyclic citrullinated peptide was positive in 7(14%)patients.Symmetrical polyarthritis pattern is predominant among clinical pattern of psoriatic arthritis which was found in 21(42%)patients.Among 7 anti-cyclic citrullinated peptide positive psoriatic arthritis patients,symmetrical polyarthritis pattern is predominant and it was found in 7(100%)patients.Among 10 rheumatoid factor positive psoriatic arthritis patients,symmetrical polyarthritis pattern is predominant and it was found in 8(80%)patients.In this study,symmetrical polyarthritis pattern is statistically associated with anti-cyclic citrullinated peptide positive psoriatic arthritis patients(P=0.008)and rheumatoid factor positive psoriatic arthritis patients(P=0.006).Human leukocyte antigen-B*07,*38 and human leukocyte antigen-C*07 were predominantly found in rheumatoid factor and anti-cyclic citrullinated peptide positive psoriatic arthritis patients.Conclusion:Both rheumatoid factor and anti-cyclic citrullinated peptide positive psoriatic arthritis patients may be in risk for development of symmetrical polyarthritis pattern.Among rheumatoid factor and anti-cyclic citrullinated peptide positive psoriatic arthritis patients,Human leukocyte antigen-B*07,*38 and human leukocyte antigen-C*07 alleles were more frequently found alleles.

The changes and clinical significance of anti CCP antibodies, complement and immunoglobulin in the pathological process of rheumatoid arthritis

Objective:To detect the serum levels of anti-Cyclic Citrullinated Peptide (CCP) antibodies, complement (C3 and C4) and immunoglobulin (IgG, IgA and IgM) in patients with rheumatoid arthritis (RA).Methods: A total of 100 patients with RA were selected as the observation group, and 60 healthy people were selected as the control group. The RA patients were divided into the high disease active group (25 cases), moderate disease active group (30 cases), low disease active group (24 cases) and remission group (21 cases) according to the disease activity score in 28 joints (DAS28 score). The levels of anti-CCP antibodies, C3, C4, IgG, IgA and IgM of each research object were detected. Difference of all the serum indexes between the observation group and control group were compared, as well as that between the RA patients in different disease activity states. Finally, the correlation of anti-CCP antibodies with C3, C4, IgG, IgA and IgM were analyzed.Results: (1) The levels of anti-CCP antibodies, C3, C4, IgG, IgA and IgM in the observation group were obviously higher than that in the control group. (2) Compared with RA in remission, the levels of anti-CCP antibodies, C3, C4, IgG, IgA and IgM of RA in activity were significant higher. Compared with the low disease active group, the levels of anti-CCP antibodies, C3, C4, IgG, IgA and IgM in the moderate and high disease active groups were obviously higher. And the anti-CCP antibodies levels in the high disease active group were significantly higher than that in the moderate ones. The anti-CCP antibodies in RA patients had significant positive correlation with C3, C4, IgG, IgA and IgM.Conclusion:The levels of anti-CCP antibodies, C3, C4, IgG, IgA and IgM in RA patients were increased obviously, and they were correlated with the disease activity of RA. They could be important indexes for the diagnosis and illness monitoring of RA.

Neutrophil-derived PAD4 induces citrullination of CKMT1 exacerbates mucosal inflammation in inflammatory bowel disease

Peptidyl arginine deiminase 4(PAD4)plays a pivotal role in infection and inflammatory diseases by facilitating the formation of neutrophil extracellular traps(NETs).However,the substrates of PAD4 and its exact role in inflammatory bowel disease(IBD)remain unclear.In this study,we employed single-cell RNA sequencing(scRNA-seq)and substrate citrullination mapping to decipher the role of PAD4 in intestinal inflammation associated with IBD.Our results demonstrated that PAD4 deficiency alleviated colonic inflammation and restored intestinal barrier function in a dextran sulfate sodium(DSS)-induced colitis mouse model.scRNA-seq analysis revealed significant alterations in intestinal cell populations,with reduced neutrophil numbers and changes in epithelial subsets upon PAD4 deletion.Gene expression analysis highlighted pathways related to inflammation and epithelial cell function.Furthermore,we found that neutrophil-derived extracellular vesicles(EVs)carrying PAD4 were secreted into intestinal epithelial cells(IECs).Within IECs,PAD4 citrullinates mitochondrial creatine kinase 1(CKMT1)at the R242 site,leading to reduced CKMT1 protein stability via the autophagy pathway.This action compromises mitochondrial homeostasis,impairs intestinal barrier integrity,and induces IECs apoptosis.IEC-specific depletion of CKMT1 exacerbated intestinal inflammation and apoptosis in mice with colitis.Clinical analysis of IBD patients revealed elevated levels of PAD4,increased CKMT1 citrullination,and decreased CKMT1 expression.In summary,our findings highlight the crucial role of PAD4 in IBD,where it modulates IECs plasticity via CKMT1 citrullination,suggesting that PAD4 may be a potential therapeutic target for IBD.

A programmable CRISPR/dCas9-based epigenetic editing system enabling loci-targeted histone citrullination and precise transcription regulation

Histone citrullination,an important post-translational modification mediated by peptidyl arginine deiminases,is essential for many physiological processes and epigenetic regulation.However,the causal relationship between histone citrullination and specific gene regulation remains unresolved.In this study,we develop a programmable epigenetic editor by fusing the peptidyl arginine deiminase(PAD)PPAD from Porphyromonas gingivalis with d Cas9.With the assistance of g RNA,PPAD-d Cas9 can recruit PPADs to specific genomic loci,enabling direct manipulation of the epigenetic landscape and regulation of gene expression.Our citrullination editor allows for the site-specific manipulation of histone H3R2,8,17 and H3R26 at target human gene loci,resulting in the activation or suppression of different genes in a locus-specific manner.Moreover,the epigenetic effects of the citrullination editor are specific and sustained.This epigenetic editor offers an accurate and efficient tool for exploring gene regulation of histone citrullination.

A citrullinated antigenic vaccine in treatment of autoimmune arthritis

Rheumatoid arthritis(RA)is an inflammatory autoimmune disease triggered by antigenic peptides with environmental and genetic risk factors.It has been shown that antigen-specific targeting could be a promising therapeutical strategy for RA by restoring immune tolerance to self-antigens without compromising normal immunity.Citrullination of antigens enhances antigenic properties and induces autoimmune responses.Here,we showed that citrullinated antigenic(citAg)vaccine ameliorated collageninduced arthritis with decreased T-helper 1(Th1)and Th17 cells,downregulated proinflammatory cytokines including interlukin-6 and tumor necrosis factor-a,and inhibited antigen recall responses.B cell receptor sequencing further revealed that citAg vaccine could dampen the dysregulated V(D)J recombination,restoring the immune repertoire.Taken together,the results demonstrated that citAg vaccine might have a therapeutic effect on RA.

三肽-10瓜氨酸的合成

本文介绍一种抗皱肽三肽-10瓜氨酸(INCI Name:Tripeptide-10 Citrulline,氨基酸序列为Lys-α-Asp-Ile-Citrulline)的固相合成方法.实验在氮气保护体系中以Rink Amide-AM树脂为载体,以Fmoc-保护和Boc-保护的氨基酸为原料、在DIC/HOBt/DMF体系中合成目标肽.实验探讨了氨基酸的最低使用比例和最佳反应时间.合成效率高,副产物少,操作简单便捷,用料少且重复性高,成本低廉,适用于实验室快速批量化生产制备.