Association between serum amyloid A and rheumatoid arthritis: A systematic review and meta-analysis

Simultaneous determination of inflammatory factors SAA and LTF based on stable element labeling and inductively coupled plasma mass spectrometry to aid in the diagnosis of infection

OBJECTIVE

The clinical value of Serum amyloid A (SAA) and Lactoferrin (LTF) has received significant attention, but their detection methods are inadequate, which limits their application. This study aims to develop a dual detection method based on stable element labeling strategies and inductively coupled plasma mass spectrometry (ICP-MS) for SAA/LTF and to assess whether it can be widely used in clinical practice.

METHODS

A duplex immunoassay system based on sandwich method was constructed. After optimization, methodological evaluation was performed with the guidelines of Clinical Laboratory Standards Institute (CLSI). Finally, 131 plasma samples were collected to analyze whether the new method is suitable for clinical detection.

RESULTS

The LoB, LLoQ, ULoQ, and linear range of the assay were 1.09 ng/mL, 3 ng/mL, 1500 ng/mL, 3-1500 ng/mL for SAA and 0.85 ng/mL, 2 ng/mL, 1200 ng/mL, 2-1200 ng/mL for LTF respectively. The recovery rates were 95.01% to 106.26%, the intra-batch precision of low, intermediate, and high-level samples was <8%, and the inter-batch of them was <11%, the deviation of interference test results was less than±10%. The Area Under the Curve (AUC) was 0.9809 for SAA, 0.8599 for LTF, and 0.9986 for combination.

CONCLUSION

The quantitative duplex immunoassay for SAA/LTF has high accuracy, good precision, and high specificity, which meets the clinical testing requirements and can be widely used in clinical practice.

The Clinical Significance of Serum Interleukin-36α Levels in Patients with Gout

BACKGROUND

Gout is a chronic inflammatory diseases caused by monosodium urate crystal deposition. However, the role of interleukin (IL)-36 in gout has not dbeen elucidated.

METHODS

We enrolled 75 subjects, including 20 healthy controls (HC), 30 patients with acute gout attack and 25 patients in remission. Baseline data were obtained through clinical interrogation and laboratory data were obtained through tests of blood samples. Serum levels of IL-36α were detected using enzyme-linked immunosorbent assay. Spearman correlation analysis was used to investigate the correlation of IL-36α with other parameters. The diagnostic value of IL-36α was demonstrated using a receiver operating characteristic curve.

RESULTS

The serum IL-36α level of gout patients in acute attack and remission stage was significantly higher than that of HC. Serum IL-36α was positively correlated with alanine transaminase (ALT) and aspartate transaminase (AST). Serum amyloid A (SAA) levels positively correlated with C-reactive protein levels and erythrocyte sedimentation rates. Glutamyl transpeptidase levels positively correlated with AST and ALT levels.

CONCLUSION

In conclusion, serum IL-36α levels were elevated in patients with gout and correlated with the clinical markers of inflammation. Our findings suggest that IL-36α may be a novel inflammatory indicator for gout.

Biomarkers of Cardiovascular Risk in Patients With Rheumatoid Arthritis: Results From the TARGET Trial

Cardiovascular disease remains an important comorbidity in patients with rheumatoid arthritis (RA), but traditional models do not accurately predict cardiovascular risk in patients with RA. The addition of biomarkers could improve prediction.

METHODS AND RESULTS

The TARGET (Treatments Against RA and Effect on FDG PET/CT) trial assessed whether different treatment strategies in RA differentially impact cardiovascular risk as measured by the change in arterial inflammation on arterial target to background ratio on fluorodeoxyglucose positron emission tomography/computed tomography scans conducted 24 weeks apart. A group of 24 candidate biomarkers supported by prior literature was assessed at baseline and 24 weeks later. Longitudinal analyses examined the association between baseline biomarker values, measured in plasma EDTA, and the change in arterial inflammation target to background ratio. Model fit was assessed for the candidate biomarkers only, clinical variables only, and models combining both. One hundred nine patients with median (interquartile range) age 58 years (53-65 years), RA duration 1.4 years (0.5-6.6 years), and 82% women had biomarkers assessed at baseline and follow-up. Because the main trial analyses demonstrated significant target to background ratio decreases with both treatment strategies but no difference across treatment groups, we analyzed all patients together. Baseline values of serum amyloid A, C-reactive protein, soluble tumor necrosis factor receptor 1, adiponectin, YKL-40, and osteoprotegerin were associated with significant change in target to background ratio. When selected candidate biomarkers were added to the clinical variables, the adjusted R2 improved from 0.20 to 0.33 (likelihood ratio P=0.0005).

CONCLUSIONS

A candidate biomarker approach identified several promising biomarkers that associate with baseline and treatment-associated changes in arterial inflammation in patients with RA. These will now be tested in an external validation cohort.

Dyslipidemia in rheumatoid arthritis: the possible mechanisms

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease, of which the leading cause of death is cardiovascular disease (CVD). The levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c) in RA decrease especially under hyperinflammatory conditions. It is conflictive with the increased risk of CVD in RA, which is called "lipid paradox". The systemic inflammation may explain this apparent contradiction. The increased systemic proinflammatory cytokines in RA mainly include interleukin-6(IL-6)、interleukin-1(IL-1)and tumor necrosis factor alpha(TNF-α). The inflammation of RA cause changes in the subcomponents and structure of HDL particles, leading to a weakened anti-atherosclerosis function and promoting LDL oxidation and plaque formation. Dysfunctional HDL can further worsen the abnormalities of LDL metabolism, increasing the risk of cardiovascular disease. However, the specific mechanisms underlying lipid changes in RA and increased CVD risk remain unclear. Therefore, this article comprehensively integrates the latest existing literature to describe the unique lipid profile of RA, explore the mechanisms of lipid changes, and investigate the impact of lipid changes on cardiovascular disease.

The role of neutrophil extracellular traps and proinflammatory damage-associated molecular patterns in idiopathic inflammatory myopathies

Idiopathic inflammatory myopathies (IIMs) are a group of systemic autoimmune diseases characterized by immune-mediated muscle injury. Abnormal neutrophil extracellular traps (NETs) can be used as a biomarker of IIM disease activity, but the mechanism of NET involvement in IIMs needs to be elucidated. Important components of NETs, including high-mobility group box 1, DNA, histones, extracellular matrix, serum amyloid A, and S100A8/A9, act as damage-associated molecular patterns (DAMPs) to promote inflammation in IIMs. NETs can act on different cells to release large amounts of cytokines and activate the inflammasome, which can subsequently aggravate the inflammatory response. Based on the idea that NETs may be proinflammatory DAMPs of IIMs, we describe the role of NETs, DAMPs, and their interaction in the pathogenesis of IIMs and discuss the possible targeted treatment strategies in IIMs.

Secondary cardiac amyloidosis in a patient with mixed connective tissue disease: A case report

We report the case of a 62-year-old man who presented with shortness of breath, cough, bilateral lower limbs' swelling, and blackish discoloration of multiple fingertips over the past 2 months. Anti-Ribonucleoprotein antibodies were found to be present, and gadolinium-based cardiac MRI showed non-vascular subendocardial enhancement with diffuse symmetrical thickening of the left ventricular wall. A diagnosis of Mixed connective tissue disease with secondary cardiac amyloidosis was thus made, and the patient was successfully managed with intravenous cyclophosphamide, corticosteroids, and other supportive measures. Although extremely rare, this case shows that secondary cardiac amyloidosis should be considered while managing patients with MCTD.

Cardiac Magnetic Resonance in Rheumatology to Detect Cardiac Involvement Since Early and Pre-clinical Stages of the Autoimmune Diseases: A Narrative Review

Autoimmune diseases (ADs) encompass multisystem disorders, and cardiovascular involvement is a well-known feature of autoimmune and inflammatory rheumatic conditions. Unfortunately, subclinical and early cardiovascular involvement remains clinically silent and often undetected, despite its well-documented impact on patient management and prognostication with an even more significant effect on severe and future MACE events as the disease progresses. Cardiac magnetic resonance imaging (MRI), today, commands a unique position of supremacy versus its competition in cardiac assessment and is the gold standard for the non-invasive evaluation of cardiac function, structure, morphology, tissue characterization, and flow with the capability of evaluating biventricular function; myocardium for edema, ischemia, fibrosis, infarction; valves for thickening, large masses; pericardial inflammation, pericardial effusions, and tamponade; cardiac cavities for thrombosis; conduction related abnormalities and features of microvascular and large vessel involvement. As precise and early detection of cardiovascular involvement plays a critical role in improving the outcome of rheumatic and autoimmune conditions, our review aims to highlight the evolving role of CMR in systemic lupus erythematosus (SLE), antiphospholipid syndrome (APS), rheumatoid arthritis (RA), systemic sclerosis (SSc), limited sclerosis (LSc), adult-onset Still's disease (AOSD), polymyositis (PM), dermatomyositis (DM), eosinophilic granulomatosis with polyangiitis (EGPA) (formerly Churg-Strauss syndrome), and DRESS syndrome (DS). It draws attention to the need for concerted, systematic global interdisciplinary research to improve future outcomes in autoimmune-related rheumatic conditions with multiorgan, multisystem, and cardiovascular involvement.

Diagnostic Accuracy of Serum Amyloid A in Acute Appendicitis: A Systematic Review and Meta-Analysis

Background: Serum amyloid A has been widely reported as a useful biochemical marker in the diagnoses of acute appendicitis. The aim of this study was to appraise the diagnostic accuracy of serum amyloid A in the diagnosis of acute appendicitis. Methods: A systematic search of several databases was conducted. The search time was from the beginning of the databases creation to March 1, 2021, and the languages were restricted to English and Chinese. Clinical studies using serum amyloid A for the diagnosis of acute appendicitis were included. The overall sensitivity and specificity were calculated by using a bivariable mixed effects model. Heterogeneity was tested using I² statistics. This study has been registered on the International Prospective Register of Systematic Reviews (PROSPERO; no. CRD42021241343). Results: Five studies comprising 668 participants were eligible for inclusion. The overall sensitivity and specificity of serum amyloid A in diagnosing acute appendicitis were 0.87 (95% confidence interval [CI], 0.79-0.92) and 0.74 (95% CI, 0.59-0.85), respectively. The positive and negative likelihood were 3.3 (95% CI, 2.1-5.4) and 0.18 (95% CI, 0.11-0.28), respectively. The area under the summary receiver operating characteristic curves was 0.89 (95% CI, 0.86-0.91). The heterogeneity was significant (I² = 82%; 95% CI [63%-100%]). Conclusions: Serum amyloid A has good diagnostic accuracy for acute appendicitis. It is expected that serum amyloid A could be helpful in the early clinical diagnosis of acute appendicitis.