Complement C3 and fatty liver disease in Rheumatoid arthritis patients: a cross-sectional study

Prevalence of Steatotic Liver Disease Among US Adults with Rheumatoid Arthritis

BACKGROUND

The prevalence of steatotic liver disease (SLD) among patients with rheumatoid arthritis (RA) remains largely unknown.

AIMS

To investigate the prevalence of SLD and liver fibrosis among patients with RA.

METHODS

We utilized data from the United States (US)-based National Health and Nutrition Examination Survey (NHANES) 2017-2020 cycle. After applying established sample weights, we estimated the age-adjusted prevalence of SLD and its subclassifications (CAP ≥ 285 dB/m), high-risk NASH (FAST score) and liver fibrosis (LSM) among participants with self-reported RA. Multivariable logistic regression was performed to identify independent risk factors for metabolic dysfunction associated SLD (MASLD), high-risk NASH and fibrosis, respectively, among participants with RA. We present adjusted odds ratios (aORs) and 95% confidence intervals (CIs).

RESULTS

Age-adjusted prevalence of MASLD among US adults with RA was 34.91% (95% CI: 24.02-47.65%). We also found that the age-adjusted prevalence of high-risk NASH (FAST score > 0.35) and significant fibrosis (LSM > 8.6 kPa) was 12.97% (95% CI: 6.89-23.07%) and 10.35% (95% CI: 5.55-18.48%), respectively. BMI ≥ 30 kg/m2, (aOR 6.23; 95% CI: 1.95-19.88), diabetes (aOR 5.90; 95% CI: 1.94-17.94), and dyslipidemia (aOR 2.83; 95% CI: 1.12-7.11) were independently associated with higher odds of MASLD among participants with RA. Diabetes (aOR 19.34; 95% CI: 4.69-79.70) was also independently associated with high-risk NASH.

CONCLUSIONS

The prevalence of MASLD, high-risk NASH, and liver fibrosis among patients with RA is equal or higher than the general population. Future studies of large cohorts are needed to substantiate the role of systemic inflammation in the pathophysiology of MASLD.

From complement to complosome in non-alcoholic fatty liver disease: When location matters

Non-alcoholic fatty liver disease (NAFLD) is a growing public health threat and becoming the leading cause of liver transplantation. Nevertheless, no approved specific treatment is currently available for NAFLD. The pathogenesis of NAFLD is multifaceted and not yet fully understood. Accumulating evidence suggests a significant role of the complement system in the development and progression of NAFLD. Here, we provide an overview of the complement system, incorporating the novel concept of complosome, and summarise the up-to-date evidence elucidating the association between complement dysregulation and the pathogenesis of NAFLD. In this process, the extracellular complement system is activated through various pathways, thereby directly contributing to, or working together with other immune cells in the disease development and progression. We also introduce the complosome and assess the evidence that implicates its potential influence in NAFLD through its direct impact on hepatocytes or non-parenchymal liver cells. Additionally, we expound upon how complement system and the complosome may exert their effects in relation with hepatic zonation in NAFLD. Furthermore, we discuss the potential therapeutic implications of targeting the complement system, extracellularly and intracellularly, for NAFLD treatment. Finally, we present future perspectives towards a better understanding of the complement system's contribution to NAFLD.

Decoding clinical and molecular pathways of liver dysfunction in Psoriatic Arthritis: Impact of cumulative methotrexate doses

BACKGROUND

The occurrence of liver abnormalities in Psoriatic Arthritis (PsA) has gained significant recognition. Identifying key factors at the clinical and molecular level can help to detect high-risk patients for non-alcoholic fatty liver disease in PsA.

OBJECTIVES

to investigate the influence of PsA and cumulative doses of methotrexate on liver function through comprehensive in vivo and in vitro investigations.

METHODS

A cross-sectional study involving 387 subjects was conducted, 200 patients with PsA, 87 NAFLD-non-PsA patients, and 100 healthy donors (HDs), age and sex-matched. Additionally, a retrospective longitudinal study was carried out, including 83 PsA patients since initiation with methotrexate. Detailed clinical, and laboratory parameters along with liver disease risk were analyzed. In vitro, experiments with hepatocyte cell line (HEPG2) were conducted.

RESULTS

PsA patients present increased liver disease risk associated with the presence of cardiometabolic comorbidities, inflammatory markers, onychopathy, and psoriasis. The treatment with PsA serum on hepatocytes encompassed inflammatory, fibrotic, cell stress, and apoptotic processes. At the molecular level, methotrexate impacts liver biology, although the cumulative doses did not affect those alterations, causing any potential damage to liver function at the clinical level. Finally, anti-PDE-4 or anti-JAK decreased the inflammatory profile induced by PsA serum on hepatocytes.

CONCLUSION

1)This study identifies the complex link between liver disease risk, comorbidities, and disease-specific features in PsA patients. 2)Methotrexate dose in PsA patients had no significant effect on liver parameters, confirmed by hepatocyte in vitro studies. 3)Anti-PDE-4 and anti-JAK therapies show promise in reducing PsA serum-induced hepatocyte activation, potentially aiding liver complication management.

Assessment of liver fibrosis in patients with rheumatoid arthritis treated with methotrexate: Utility of fibroscan and biochemical markers in routine clinical practice

OBJECTIVES

To study the prevalence of liver fibrosis (LF) measured by FibroScan and APRI index in patients with rheumatoid arthritis (AR) undergoing treatment with methotrexate (MTX).

METHODS

We included 59 patients with RA on MTX. Medical records, FibroScan measures and serological markers of liver damage were compared on the basis of cumulative methotrexate dose.

RESULTS

Mean treatment duration was 82.4±65.1 months and mean cumulative dose was 5214.5±4031.9mg. Five patients met LF criteria by fibroscan, while only one patient had a suggestive APRI score. No statistically significant differences were found in terms of LF measured by both APRI and fibroScan between patients with cumulative doses above and below 4000mg. There was also no relationship between LF and treatment duration.

CONCLUSIONS

The occurrence of LF in patients with RA on MTX is a multifactorial process that does not seem directly related to its cumulative dose. FibroScan may be a useful technique in clinical practice to screen for this complication.

Prevalence of Nonalcoholic Fatty Liver Disease in Patients With Rheumatoid Arthritis: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Previous studies have shown a potential association between nonalcoholic fatty liver disease (NAFLD) and some immune-mediated inflammatory diseases, such as rheumatoid arthritis (RA), but this association has not been analyzed systematically. Therefore, we aimed to perform a systematic review and meta-analysis to ascertain a pooled prevalence estimate of NAFLD among patients with RA to fill this gap in knowledge.

METHODS

We conducted a literature search in PubMed, Embase, Web of Science, Scopus, and ProQuest, for observational studies published from inception to August 31, 2022, which reported prevalence of NAFLD in 100 or more adult (age, ≥18 y) patients with RA. To be included, NAFLD diagnosis was based on either imaging or histologic assessment. The results were presented as pooled prevalence, odds ratio, and 95% CI. The I2 statistic was used to measure the heterogeneity between studies.

RESULTS

This systematic review included 9 eligible studies derived from 4 continents comprising 2178 patients (78.8% women) with RA. The pooled prevalence of NAFLD was 35.3% (95% CI, 19.9-50.6; I2 = 98.6%; P < .001) in patients with RA. All studies used ultrasound for the diagnosis of NAFLD, except for 1 study that used transient elastography. The pooled prevalence of NAFLD in men with RA was significantly higher than in women with RA (35.2%; 95% CI, 24.0-46.5 compared with 22.2%; 95% CI, 17.9-26.58; P for interaction = .048). Each 1-unit increase in body mass index was associated directly with a 24% increased risk of NAFLD in RA patients (adjusted odds ratio, 1.24; 95% CI, 1.17-1.31; I2 = 0.0%; P = .518).

CONCLUSIONS

Based on this meta-analysis, 1 in 3 patients with RA had NAFLD, which appears comparable with its overall prevalence among the general population. Clinicians should actively screen for NAFLD in patients with RA.

C3-dependent effector functions of complement

C3 is the central effector molecule of the complement system, mediating its multiple functions through different binding sites and their corresponding receptors. We will introduce the C3 forms (native C3, C3 [H₂ O], and intracellular C3), the C3 fragments C3a, C3b, iC3b, and C3dg/C3d, and the C3 expression sites. To highlight the important role that C3 plays in human biological processes, we will give an overview of the diseases linked to C3 deficiency and to uncontrolled C3 activation. Next, we will present a structural description of C3 activation and of the C3 fragments generated by complement regulation. We will proceed by describing the C3a interaction with the anaphylatoxin receptor, followed by the interactions of opsonins (C3b, iC3b, and C3dg/C3d) with complement receptors, divided into two groups: receptors bearing complement regulatory functions and the effector receptors without complement regulatory activity. We outline the molecular architecture of the receptors, their binding sites on the C3 activation fragments, the cells expressing them, the diversity of their functions, and recent advances. With this review, we aim to give an up-to-date analysis of the processes triggered by C3 activation fragments on different cell types in health and disease contexts.

Association of complement components with the risk and severity of NAFLD: A systematic review and meta-analysis

Background

It is generally believed that complement system is strongly associated with the risk of nonalcoholic fatty liver disease (NAFLD). However, complement system contains a variety of complement components, and the relationship between complement components and the risk and severity of NAFLD is inconsistent. The aim of this meta-analysis was to evaluate the association of complement components with the risk and severity of NAFLD.

Methods

We searched PubMed, Embase, Cochrane Library, Google Scholar, Scopus, and ZhiWang Chinese databases from inception to May 2022 for observational studies reporting the risk of NAFLD with complement components. Random-effects meta-analysis was used to obtain pooled estimates of the effect due to heterogeneity.

Results

We identified 18 studies with a total of 18560 included subjects. According to recent studies, levels of complement component 3 (C3) (mean difference (MD): 0.43, 95% confidence interval (CI) 0.26-0.60), complement component 4 (C4) (MD: 0.04, 95% CI 0.02-0.07), complement component 5(C5) (MD: 34.03, 95% CI 30.80-37.27), complement factor B (CFB) (MD: 0.22, 95% CI 0.13-0.31) and acylation stimulating protein (ASP) (standard mean difference (SMD): 5.17, 95% CI 2.57-7.77) in patients with NAFLD were significantly higher than those in the control group. However, no statistical significance was obtained in complement factor D (CFD) levels between NAFLD and non-NAFLD (MD=156.51, 95% CI -59.38-372.40). Moreover, the levels of C3, C5, CFB, and ASP in patients with moderate and severe NAFLD were significantly higher than those in patients with mild NAFLD. Except for C4 and CFD, the included studies did not explore the changes in the severity of NAFLD according to the concentration of C4 and CFD.

Conclusions

This meta-analysis demonstrates that an increase in complement components including C3, C5, CFB, and ASP is associated with an increased risk and severity of NAFLD, indicating that they may be good biomarkers and targets for the diagnosis and treatment of NAFLD.

Systematic review registration

PROSPERO [https://www.crd.york.ac.uk/PROSPERO/], identifier CRD42022348650.

Nonalcoholic fatty liver disease in inflammatory arthritis: Relationship with cardiovascular risk

Liver disease is one of the most important causes of morbidity and mortality worldwide whose prevalence is dramatically increasing. The first sign of hepatic damage is inflammation which could be accompanied by the accumulation of fat called non-alcoholic fatty liver disease (NAFLD), causing damage in the hepatocytes. This stage can progress to fibrosis where the accumulation of fibrotic tissue replaces healthy tissue reducing liver function. The next stage is cirrhosis, a late phase of fibrosis where a high percentage of liver tissue has been replaced by fibrotic tissue and liver functionality is substantially impaired. There is a close interplay of cardiovascular disease (CVD) and hepatic alterations, where different mechanisms mediating this relation between the liver and systemic vasculature have been described. In chronic inflammatory diseases such as rheumatoid arthritis (RA) and psoriatic arthritis (PsA), in which the CVD risk is high, hepatic alterations seem to be more prevalent compared to the general population and other rheumatic disorders. The pathogenic mechanisms involved in the development of this comorbidity are still unraveled, although chronic inflammation, autoimmunity, treatments, and metabolic deregulation seem to have an important role. In this review, we will discuss the involvement of liver disease in the cardiovascular risk associated with inflammatory arthritis, the pathogenic mechanisms, and the recognized factors involved. Likewise, monitoring of the liver disease risk in routine clinical practice through both, classical and novel techniques and indexes will be exposed. Finally, we will examine the latest controversies that have been raised about the effects of the current therapies used to control the inflammation in RA and PsA, in the liver damage of those patients, such as methotrexate, leflunomide or biologics.

Perspectives on the use of non-biological pharmacotherapy for adult-onset Still's disease

INTRODUCTION

The treatment of the patients with adult-onset Still's disease (AOSD) remains largely empirical and it is based on the administration of immunosuppressive drugs. In this work, we described the use of non-biological pharmacotherapies for AOSD.

AREA COVERED

Although nonsteroidal anti-inflammatory drugs (NSAIDs) are employed during the diagnostic phase, glucocorticoids (GCs) are the first-line therapy, administered at the beginning of the disease. As second-line therapy, conventional synthetic disease modifying anti-rheumatic drugs (csDMARDs) are used when GCs do not fully control the disease and/or to reduce the dosage of concomitant GCs. Methotrexate (MTX) is the most commonly administered csDMARDs whereas calcineurin inhibitors (CNIs) are used in severe patients. The lack of achievement of clinical response may lead to the administration of biologic DMARDs, with or without csDMARDs.

EXPERT OPINION

The management of AOSD may benefit from the administration of non-biological pharmacotherapies, including GCs, MTX, and CNIs. These therapies showed efficacy in inducing a clinical response, in managing life-threatening complications, and may be well tolerated in combination with biologic DMARDs. However, further specific studies are needed to fully clarify the specific role of such drugs in clinical practice to improve the management of AOSD and to provide a more tailored treatment.

Association Between Metabolic Dysfunction-Associated Fatty Liver Disease and Cardiovascular Risk in Patients With Rheumatoid Arthritis: A Cross-Sectional Study of Chinese Cohort

Background

The nomenclature from non-alcoholic fatty liver disease (NAFLD) to metabolic dysfunction-associated fatty liver disease (MAFLD) is considered to identify more cardiovascular disease (CVD) risks in the general population. Patients with rheumatoid arthritis (RA) carry an excess risk for CVD. However, the prevalence of MAFLD and its relationship with CVD risks in RA have not been reported.

Methods

This cross-sectional study retrospectively analyzed clinical data from a Chinese RA cohort. MAFLD was diagnosed according to the criteria proposed by an international expert panel from 22 countries in 2020. CVD risk in patients with RA was estimated by the Prediction for Atherosclerotic Cardiovascular Disease Risk in China with a 1.5 multiplication factor.

Results

Among 513 included patients with RA, 78.4% were women and the mean ± SD age was 51.8 ± 12.6 years. The prevalence of MAFLD was 21.4%. There were 10.9% patients with RA concomitated with CVD events and 32.4% with a high-estimated 10-year CVD risk. Besides a higher liver fibrosis score and a higher ratio of advanced fibrosis, RA patients with MAFLD had a higher rate of CVD events (17.3 vs. 9.2%) and a higher proportion of high estimated 10-year CVD risk (55.5 vs. 26.1%) than those without. Multivariate logistic regression analysis showed that MAFLD was associated with an increase in CVD events [adjusted odds ratio (AOR) = 2.190, 95% CI 1.135–4.227] and high estimated 10-year CVD risk (AOR = 2.483, 95% CI 1.412–4.365, all p < 0.05).

Conclusion

Metabolic dysfunction-associated fatty liver disease was associated with increased CVD risk in patients with RA, which implies the importance of early detection and management of MAFLD in patients with RA.

Beyond Systemic Lupus Erythematosus and Anti-Phospholipid Syndrome: The Relevance of Complement From Pathogenesis to Pregnancy Outcome in Other Systemic Rheumatologic Diseases

Evidence about the relevance of the complement system, a highly conserved constituent of the innate immunity response that orchestrates the elimination of pathogens and the inflammatory processes, has been recently accumulated in many different rheumatologic conditions. In rheumatoid arthritis, complement, mainly the classical pathway, contributes to tissue damage especially in seropositive subjects, with complement activation occurring in the joint. Data about complement pathways in psoriatic arthritis are dated and poorly consistent; among patients with Sjögren syndrome, hypocomplementemia exerts a prognostic role, identifying patients at risk of extra-glandular manifestations. Hints about complement involvement in systemic sclerosis have been recently raised, following the evidence of complement deposition in affected skin and in renal samples from patients with scleroderma renal crisis. In vasculitides, complement plays a dual role: on one hand, stimulation of neutrophils with anti-neutrophil cytoplasmic antibodies (ANCA) results in the activation of the alternative pathway, on the other, C5a induces translocation of ANCA antigens, favouring the detrimental role of antibodies. Complement deposition in the kidneys identifies patients with more aggressive renal disease; patients with active disease display low serum levels of C3 and C4. Even though in dermatomyositis sC5b-9 deposits are invariably present in affected muscles, data on C3 and C4 fluctuation during disease course are scarce. C3 and C1q serum levels have been explored as potential markers of disease activity in Takayasu arteritis, whereas data in Behçet disease are limited to in vitro observations. Pregnancies in women with rheumatologic conditions are still burdened by a higher rate of pregnancy complications, thus the early identification of women at risk would be invaluable. A fine-tuning of complement activation is required from a physiological progression of pregnancy, from pre-implantation stages, through placentation to labour. Complement deregulation has been implicated in several pregnancy complications, such as recurrent abortion, eclampsia and premature birth; low complement levels have been shown to reliably identify women at risk of complications. Given its physiologic role in orchestrating pregnancy progression and its involvement as pathogenic effector in several rheumatologic conditions, complement system is an attractive candidate biomarker to stratify the obstetric risk among women with rheumatologic conditions.

Prevalence and risk factors of moderate to severe hepatic steatosis in patients with rheumatoid arthritis: an ultrasonography cross-sectional case-control study

Background:

The independent association between hepatic steatosis and rheumatoid arthritis is poorly defined.

Methods:

The presence of moderate to severe steatosis was assessed, using liver ultrasonography, in 364 consecutive non-diabetic subjects (223 patients with rheumatoid arthritis and 141 age- and sex-matched healthy controls). Adjusted multiple regression analysis was performed to explore the association between rheumatoid arthritis and moderate to severe steatosis in the overall sample and identify independent risk factors in the rheumatoid arthritis subgroup.

Results:

The prevalence of moderate to severe steatosis in the overall sample was 31.3%, with a significantly higher prevalence in patients with rheumatoid arthritis than healthy controls (38.7% versus 19.7%, p < 0.0001). After adjustment for sex, age, cholesterol, triglycerides, body mass index, waist, hypertension and smoke, rheumatoid arthritis remained significantly associated with moderate to severe steatosis [odds ratio (95% confidence interval) = 2.24 (1.31, 3.84); p = 0.003]. In the rheumatoid arthritis group, male sex, higher body mass index, higher triglycerides concentrations and higher cumulative dosage of methotrexate [odds ratio (95% confidence interval) = 1.11 (1.01, 1.23); p = 0.026] were significantly associated with moderate to severe steatosis, while systemic inflammation, disease activity, use of steroids and biologics were not.

Conclusion:

Rheumatoid arthritis is independently associated with moderate to severe steatosis, with male sex, higher body mass index and cumulative dose of methotrexate being predisposing factors. Further prospective studies are warranted to confirm our findings and to investigate the effect of steatosis on liver outcomes in the rheumatoid arthritis population.

Association between complement C3 and the prevalence of metabolic-associated fatty liver disease in a Chinese population: a cross-sectional study

OBJECTIVES

Recently studies demonstrated that adipose tissue can produce and release complement C3 and serum complement C3 levels were associated with diabetes mellitus, metabolic syndrome and non-alcoholic fatty liver disease (NAFLD). Thus, we plan to investigate the association of complement C3 levels and the presence of metabolic-associated fatty liver disease (MAFLD).

DESIGN

Observational study with a cross-sectional sample.

SETTING

This study surveyed 4729 participants in Zhejiang province, China.

PARTICIPANTS

55 participants were excluded for acute infection and 1001 participants were excluded for lack of ultrasonography diagnoses and complete or partial absence of laboratory tests. The final sample size was 3673 participants.

OUTCOME MEASURES

Spearman correlation analysis was used to examine the correlations between complement C3 levels and variables. Binary logistic regression was carried out to evaluate the association between complement C3 levels and the presence of MAFLD after adjustment for demographic and biochemical variables. Mediation effects were used to explore whether insulin resistance (IR), hyperlipidaemia and obesity mediated the association between complement C3 and MAFLD.

RESULTS

Participants with MAFLD had higher complement C3 levels and complement C3 levels were closely associated with body mass index, waist circumference, alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transpeptidase and homoeostasis model assessment (HOMA)-IR. The presence of MAFLD increased with the increase of complement C3 levels and the presence of MAFLD were highest in the HOMA-IR ≥2.5 participants. We found the OR and Cl of standardised C3 for MAFLD was 1.333 (1.185-1.500), each 1 SD increase in C3 would increase the presence of MAFLD by 33.3%, and obesity partly mediated the effect of complement C3 on the presence of MAFLD.

CONCLUSIONS

The present results suggest that complement C3 can be used as a risk factor for the presence of MAFLD after adjustment for confounding variables and obesity may partly mediate the effect of complement C3 on the presence of MAFLD.

Causal Relationship Between Complement C3, C4, and Nonalcoholic Fatty Liver Disease: Bidirectional Mendelian Randomization Analysis

The complement system is activated during the development of nonalcoholic fatty liver disease (NAFLD). We aimed to evaluate the causal relationship between serum C3 and C4 levels and NAFLD. After exclusion criteria, a total of 1600 Chinese Han men from the Fangchenggang Area Male Health and Examination Survey cohort were enrolled in cross-sectional analysis, while 572 participants were included in the longitudinal analysis (average follow-up of 4 years). We performed a bidirectional Mendelian randomization (MR) analysis using two C3-related, eight C4-related and three NAFLD-related gene loci as instrumental variables to evaluate the causal associations between C3, C4, and NAFLD risk in cross-sectional analysis. Per SD increase in C3 levels was significantly associated with higher risk of NAFLD (OR = 1.65, 95% CI 1.40, 1.94) in cross-sectional analysis while C4 was not (OR = 1.04, 95% CI 0.89, 1.21). Longitudinal analysis produced similar results (HR_C3 = 1.20, 95% CI 1.02, 1.42; HR_C4 = 1.10, 95% CI 0.94, 1.28). In MR analysis, there were no causal relationships for genetically determined C3 levels and NAFLD risk using unweighted or weighted GRS_C3 (β_{E_unweighted} = -0.019, 95% CI -0.019, -0.019, p = 0.202; β_{E_weighted} = -0.019, 95% CI -0.019, -0.019, p = 0.322). Conversely, serum C3 levels were significantly effected by the genetically determined NAFLD (β_{E_unweighted} = 0.020, 95% CI 0.020, 0.020, p = 0.004; β_{E_weighted} = 0.021, 95% CI 0.020, 0.021, p = 0.004). Neither the direction from C4 to NAFLD nor the one from NAFLD to C4 showed significant association. Our results support that the change in serum C3 levels but not C4 levels might be caused by NAFLD in Chinese Han men.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43657-021-00023-0.

Complement Component C3: A Novel Biomarker Participating in the Pathogenesis of Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is currently the most common cause of chronic liver disorder worldwide. The pathological spectrum of NAFLD ranges from simple steatosis to non-alcoholic steatohepatitis (NASH) that induces progressive liver cirrhosis and eventually hepatocellular carcinoma (HCC). However, the molecular mechanisms driving the transformation of NASH are obscure. There is a compelling need for understanding the pathogenic mechanisms of NASH, and thereby providing new insight into mechanism-based therapy. Currently, several studies reported that complement system, an innate immune system, played an important role in the pathogenesis of NAFLD, which was also proved by our recent study. Complement component 3 (C3), a protein of the innate immune system, plays a hub role in the complement system. Herein, we present a review on the role and molecular mechanism of C3 in NASH as well as its implication in NASH diagnosis and treatment.

Complement component 3 as biomarker of disease activity and cardiometabolic risk factor in rheumatoid arthritis and spondyloarthritis

Objective

To analyze the relationship between complement component 3 (C3) and the prevalence of cardiometabolic risk factors and disease activity in the rheumatic diseases having the highest rates of cardiovascular morbidity and mortality: rheumatoid arthritis (RA), psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA).

Methods

This is a cross-sectional study including 200 RA, 80 PsA, 150 axSpA patients and 100 healthy donors. The prevalence of cardiometabolic risk factors [obesity, insulin resistance, type 2 diabetes mellitus, hyperlipidemia, apolipoprotein B/apolipoprotein A (apoB/apoA) and atherogenic risks and hypertension] was analyzed. Serum complement C3 levels, inflammatory markers and disease activity were evaluated. Cluster analysis was performed to identify different phenotypes. Receiver operating characteristic (ROC) curve analysis to assess the accuracy of complement C3 as biomarker of insulin resistance and disease activity was carried out.

Results

Levels of complement C3, significantly elevated in RA, axSpA and PsA patients, were associated with the prevalence of cardiometabolic risk factors. Hard clustering analysis identified two distinctive phenotypes of patients depending on the complement C3 levels and insulin sensitivity state. Patients from cluster 1, characterized by high levels of complement C3 displayed increased prevalence of cardiometabolic risk factors and high disease activity. ROC curve analysis showed that non-obesity related complement C3 levels allowed to identify insulin resistant patients.

Conclusions

Complement C3 is associated with the concomitant increased prevalence of cardiometabolic risk factors in rheumatoid arthritis and spondyloarthritis. Thus, complement C3 should be considered a useful marker of insulin resistance and disease activity in these rheumatic disorders.

Exploration of Serum Marker Proteins in Mice Induced by Babesia microti Infection Using a Quantitative Proteomic Approach

Babesia microti is a protozoan that mainly parasitizes rodent and human erythrocytes. B. microti infection can result in changes in the expression levels of various proteins in the host serum. To explore the mechanism underlying the regulation of serum proteins by the host during B. microti infection, this study used a data-independent acquisition (DIA) quantitative proteomic approach to perform comprehensive quantitative proteomic analysis on the serum of B. microti-infected mice. We identified and analysed 333 serum proteins during the infectious stage and recovery stage within 30 days of infection by B. microti in mice. Through quantitative analysis, we found 57 proteins differentially expressed in the infection stage and 69 proteins differentially expressed in the recovery stage. Bioinformatics analysis revealed that these differentially expressed proteins were mainly concentrated in organelles, cell parts, and extracellular regions that are mainly involved in immune system, metabolic, and cellular processes. Additionally, the differentially expressed proteins mainly had catalytic activity. Kyoto Encyclopedia of Genes and Genome (KEGG) pathway analysis showed that many of the differentially expressed proteins participate in the complement and coagulation cascade reaction, including complement C3, complement FP, and coagulation factor XII. The results of this study can provide more information for the selection of biomarkers for the early clinical monitoring of babesiosis and help in the treatment of babesiosis.

Fatty liver in Pakistani cohort with rheumatoid arthritis

Objective:

To determine the frequency of fatty liver (non-alcoholic) disease, Framingham 10-year cardiovascular risk score in rheumatoid arthritis patients.

Methods:

This study was conducted from September 1^st to March 19, 2019, at Rheumatology OPD, Central Park Medical College Lahore. One hundred ninety two seropositive rheumatoid arthritis patients were recruited. Demographic details were noted, BP, BMI, smoking habits, and waist circumference were noted, then sent to radiology department for ultrasound scan of abdomen by an expert radiologist. On next day 10 ml blood was taken by phlebotomist for lipid profile and fasting blood sugar levels, after availability of results 10-years Framingham cardiovascular risk score was calculated.

Results:

Females were (81.3%) mean age of (45.4) years, fatty liver was present in n=39 (20.3%). In positive cases comorbid like metabolic syndrome was present (71.8%), diabetes mellitus (33.3%), hypertension (59%) FRS score (intermediate to high in (33.3%), history of hakeem/desi medication use (51.3%), while on regression analysis all study parameters except DMARD’s had significant association with fatty liver (p<0.05).

Conclusion:

Nonalcoholic fatty liver disease is very widely prevalent in rheumatoid arthritis patients. As in general population, it is multifactorial in origin and needs careful monitoring and treatment.

Complement C3 and Nonalcoholic Fatty Liver Disease in Chronic Kidney Disease Patients: A Pilot Study

CONTEXT

Evidences have suggested complement C3 is a biomarker for nonalcoholic fatty liver disease (NAFLD) in the general population.

OBJECTIVE

The present study was conducted to explore the predictive function of C3 for NAFLD in chronic kidney disease (CKD) patients.

DESIGN, SETTING, AND PARTICIPANTS

CKD patients were recruited for evaluation of their liver function, kidney function, serum lipids, glycated hemoglobin, blood, and immune function. The glomerular filtration rate was calculated using the CKD-EPI equation. NAFLD was diagnosed according to predefined ultrasonographic criteria.

RESULTS

A total of 648 consecutive CKD patients were included, with 216 (33.3%) patients diagnosed with NAFLD. The NAFLD group had significant higher levels of serum protein, serum albumin, triglycerides, glycated hemoglobin, complement C3, hemoglobin (p = 0.001), alanine aminotransferase (p = 0.002), estimated glomerular filtration rate (p = 0.007), and C4 (p = 0.043) and lower levels of cystatin C, β2-microglobulin, proteinuria (p = 0.001), and high-density lipoprotein cholesterol (p = 0.008). In a logistic regression model, only complement C3 (OR = 1.003; 95% CI 1.002-1.004, p = 0.001) was associated with a higher likelihood of being diagnosed with NAFLD. Finally, we constructed ROC curves for complement C3 for prediction of having NAFLD. The best cut-off for complement C3 was 993.5 mg/L and it yielded a sensitivity of 63.9% and a specificity of 70.1%.

CONCLUSION

Our study revealed that complement C3 can be used as a surrogate biomarker of NAFLD in CKD patients.

Elevated levels of inflammatory markers in women with rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune and progressive disease. Evidence indicates that inflammatory mediators may contribute to the genesis and/or evolution of this clinical condition. Thus, the objective was to evaluate and compare the plasma levels of Interleukin-17 (IL-17), Tumor Necrosis Factor-Alpha (TNF-α) and Complement 3 (C3) in women with RA and healthy controls (HC), as well as to evaluate the association them with the disease activity. 25 women with RA and 15 HC were recruited. Plasma levels of biomarkers were measured by ELISA. All statistical analyzes were performed with a significance level set at α = 0.05. In the women with RA, the median age was 55 and, in the HC, was 50 years. The median value of DAS-28 was 3.79. The plasma levels of IL-17 (p = .03), TNF-α (p ≤ 0.01) and C3 (p ≤ 0.01) were higher in women with RA. The ROC curve showed that TNF- α has a higher discriminating ability than IL-17 and C3. DAS-28 score correlated significantly with C3 levels in women with RA (r = 0.91; p < .01). These findings reaffirm the participation of the immune system in pathophysiology of RA, suggest that TNF-α levels may be a good biomarker and that elevated C3 levels contribute to the worsening of the disease.

Adipocytokines in Rheumatoid Arthritis: The Hidden Link between Inflammation and Cardiometabolic Comorbidities

Rheumatoid arthritis is a chronic autoimmune disease affecting typically synovial joints and leading to progressive articular damage, disability, and reduced quality of life. Despite better recent therapeutic strategies improving long-term outcomes, RA is associated with a high rate of comorbidities, infections, malignancies, and cardiovascular disease (CVD). Remarkably, some well-known pathogenic proinflammatory mediators in RA, such as interleukin-1β (IL-1β) and tumor necrosis factor (TNF), may play a pivotal role in the development of CVD. Interestingly, different preclinical and clinical studies have suggested that biologic agents commonly used to treat RA patients may be effective in improving CVD. In this context, the contribution of adipocytokines has been suggested. Adipocytokines are pleiotropic molecules, mainly released by white adipose tissue and immune cells. Adipocytokines modulate the function of different tissues and cells, and in addition to energy homeostasis and metabolism, amplify inflammation, immune response, and tissue damage. Adipocytokines may contribute to the proinflammatory state in RA patients and development of bone damage. Furthermore, they could be associated with the occurrence of CVD. In this study, we reviewed available evidence about adipocytokines in RA, because of their involvement in disease activity, associated CVD, and possible biomarkers of prognosis and treatment outcome and because of their potential as a possible new therapeutic target.