Citrullinated and malondialdehyde-acetaldehyde-modified fibrinogen activates macrophages and promotes profibrotic responses in human lung fibroblasts.

The objective of this study was to assess fibrinogen (FIB) comodified with citrulline (CIT) and/or malondialdehyde-acetaldehyde (MAA) initiates macrophage-fibroblast interactions, leading to extracellular matrix (ECM) deposition that characterizes rheumatoid arthritis-associated interstitial lung disease (RA-ILD). Macrophages (Mϕ) were stimulated with native-FIB, FIB-CIT, FIB-MAA, or FIB-MAA-CIT. Supernatants (SNs) [Mϕ-SN (U-937-derived) or MϕP-SN (PBMC-derived)] or direct antigens were coincubated with human lung fibroblasts (HLFs).

Antibodies to Malondialdehyde-Acetaldehyde Adduct Are Associated With Prevalent and Incident Rheumatoid Arthritis-Associated Interstitial Lung Disease in US Veterans.

Objective: The objective of this study is to determine the associations of protein-specific anti-malondialdehyde-acetaldehyde (MAA) antibodies with prevalent and incident rheumatoid arthritis-interstitial lung disease (RA-ILD).

Methods: Within a multicenter, prospective cohort of US veterans with RA, RA-ILD was validated by medical record review of clinical diagnoses, chest imaging, and pathology. Serum antibodies to MAA-albumin, MAA-collagen, MAA-fibrinogen, and MAA-vimentin (IgA, IgM, and IgG) were measured by a standardized enzyme-linked immunosorbent assay.

Combined repetitive inhalant endotoxin and collagen-induced arthritis drive inflammatory lung disease and arthritis severity in a testosterone-dependent manner.

Respiratory-related diseases are a leading cause of death in rheumatoid arthritis (RA) and are disproportionately higher in men, which may be attributable to environmental risk factors. Animal studies have demonstrated potentiated autoimmunity, arthritis, and profibrotic/inflammatory lung disease with a combination of airborne exposures and collagen-induced arthritis (CIA). This study aimed to determine whether hormone-dependent differences explained these observations.

Serum alarmins and the risk of incident interstitial lung disease in rheumatoid arthritis.

Objectives: To quantify associations of serum alarmins with risk of rheumatoid arthritis-associated interstitial lung disease (RA-ILD).

Methods: Using serum collected at enrolment, three alarmins (IL-33, thymic stromal lymphopoietin [TSLP] and IL-25) were measured in a multicentre prospective RA cohort. ILD was classified using systematic medical record review.

Citrullinated and malondialdehyde-acetaldehyde modified fibrinogen activates macrophages and promotes an aggressive synovial fibroblast phenotype in patients with rheumatoid arthritis.

Objective: Post-translational protein modifications with malondialdehyde-acetaldehyde (MAA) and citrulline (CIT) are implicated in the pathogenesis of rheumatoid arthritis (RA). Although precise mechanisms have not been elucidated, macrophage-fibroblast interactions have been proposed to play a central role in the development and progression of RA. The purpose of our study was to evaluate the downstream effects of macrophage released soluble mediators, following stimulation with fibrinogen (FIB) modified antigens, on human fibroblast-like synoviocytes (HFLS).

A novel reactive aldehyde species inhibitor prevents the deleterious effects of ethanol in an animal model of alcoholic liver disease.

Background And Aims: Current treatment strategies for alcoholic liver disease (ALD) are limited by the lack of agents specifically targeting the metabolic breakdown products of ethanol. Reactive aldehyde species (RASP) inhibitors have been developed that have the capability to sequester these aldehyde byproducts, potentially limiting toxicity. The purpose of this study was to determine if the RASP inhibitor ADX-629 could target these metabolic breakdown products in a mouse model of ALD.

Peptidyl arginine deiminase expression and macrophage polarization following stimulation with citrullinated and malondialdehyde-acetaldehyde modified fibrinogen.

Objective: Post-translational modifications of extracellular matrix proteins such as fibrinogen may lead to tolerance loss and have been implicated in rheumatoid arthritis (RA) pathogenesis. The purpose of this study was to determine whether fibrinogen (FIB) modified with citrulline (CIT), malondialdehyde-acetaldehyde (MAA) or both leads to altered macrophage polarization, peptidyl arginine deiminase (PAD) expression, or production of citrullinated proteins.

Methods: PMA-treated U-937 cells (M0 cells) were stimulated with MAA, CIT or MAA-CIT modified FIB.

Increased susceptibility to organic dust exposure-induced inflammatory lung disease with enhanced rheumatoid arthritis-associated autoantigen expression in HLA-DR4 transgenic mice.

Immunogenetic as well as environmental and occupational exposures have been linked to the development of rheumatoid arthritis (RA), RA-associated lung disease, and other primary lung disorders. Importantly, various inhalants can trigger post-translational protein modifications, resulting in lung autoantigen expression capable of stimulating pro-inflammatory and/or pro-fibrotic immune responses. To further elucidate gene-environment interactions contributing to pathologic lung inflammation, we exploited an established model of organic dust extract (ODE) exposure with and without collagen-induced arthritis (CIA) in C57BL/6 wild type (WT) versus HLA-DR4 transgenic mice.

Elevations in adipocytokines and mortality in rheumatoid arthritis.

Objectives: This study assessed whether circulating levels of adiponectin and leptin are associated with higher mortality in patients with RA.

Methods: Participants were adults from the Veterans Affairs RA Registry. Adipokines and inflammatory cytokines were measured as part of a multi-analyte panel on banked serum at enrolment.

Circulating Adipokines and Associations With Incident Cardiovascular Disease in Rheumatoid Arthritis.

Objective: To assess whether circulating levels of adiponectin, leptin, and fibroblast growth factor 21 (FGF-21) are associated with incident cardiovascular disease (CVD) in rheumatoid arthritis (RA).

Methods: Adipokines were measured using banked enrollment serum from patients with RA and dichotomized above/below the median value. Incident CVD events (coronary artery disease [CAD], stroke, heart failure [HF] hospitalization, venous thromboembolism, CVD-related deaths) were identified using administrative data and the National Death Index.

Identification of Immunoglobulin G Autoantibody Against Malondialdehyde-Acetaldehyde Adducts as a Novel Serological Biomarker for Ulcerative Colitis.

Introduction: Inflammatory bowel disease (IBD) is associated with immune responses with oxidative stress wherein high levels of malondialdehyde result in the formation of a highly stable and immunogenic malondialdehyde-acetaldehyde adduct (MAA). Thus, this study evaluated the status of MAA and anti-MAA antibody isotypes in IBD and their potential as novel serological biomarkers for differentiating ulcerative colitis (UC) from Crohn's disease (CD).

Methods: Levels of MAA and anti-MAA antibodies were examined in patients with IBD (171), non-IBD gastrointestinal diseases (77), and controls (83) from 2 independent cohorts using immunohistochemistry and enzyme-linked immunosorbent assay.

The impact of airborne endotoxin exposure on rheumatoid arthritis-related joint damage, autoantigen expression, autoimmunity, and lung disease.

Airborne biohazards are risk factors in the development and severity of rheumatoid arthritis (RA) and RA-associated lung disease, yet the mechanisms explaining this relationship remain unclear. Lipopolysaccharide (LPS, endotoxin) is a ubiquitous inflammatory agent in numerous environmental and occupational air pollutant settings recognized to induce airway inflammation. Combining repetitive LPS inhalation exposures with the collagen induced arthritis (CIA) model, DBA1/J mice were assigned to either: sham (saline injection/saline inhalation), CIA (CIA/saline), LPS (saline/LPS 100 ng inhalation), or CIA + LPS for 5 weeks.

Performance of a commercially available multiplex platform in the assessment of circulating cytokines and chemokines in patients with rheumatoid arthritis and osteoarthritis.

Background/objective: Cytokines and chemokines (cytokines) are central to rheumatoid arthritis (RA) pathogenesis, with increasing use of multiplex immunoassays in clinical/research settings. Rheumatoid factor (RF) may interfere with assay outcomes by nonspecifically binding detection analytes. We evaluated the performance of a commercially available multiplex platform, including assessment of the impact of RF depletion.

Disease activity, cytokines, chemokines and the risk of incident diabetes in rheumatoid arthritis.

Purpose: Rheumatoid arthritis (RA) is associated with a higher risk of diabetes mellitus (DM). Our aim was to determine associations between inflammatory disease activity (including evaluation of specific cytokines and chemokines) and incident DM.

Methods: Participants were adults with physician-confirmed RA from Veteran's Affairs Rheumatoid Arthritis Registry.

Associations between an expanded autoantibody profile and treatment responses to biologic therapies in patients with rheumatoid arthritis.

Background: Although biologics represent a major advance in rheumatoid arthritis (RA), many patients fail to achieve adequate responses to these agents. We examined whether combined positivity to three well-characterized autoantibodies predicts treatment response among RA patients initiating biologics.

Methods: The study included biologic-naïve patients initiating anti-TNF treatment, biologic-exposed patients switching to rituximab or tocilizumab, and patients (biologic naïve or exposed) initiating abatacept.

Autoantibodies to Malondialdehyde-Acetaldehyde Are Detected Prior to Rheumatoid Arthritis Diagnosis and After Other Disease Specific Autoantibodies.

Objective: To examine serum autoantibodies to malondialdehyde-acetaldehyde (MAA) prior to rheumatoid arthritis (RA) diagnosis.

Methods: Concentrations of anti-MAA antibody isotypes, anti-cyclic citrullinated peptide 2 (anti-CCP-2), and IgM rheumatoid factor (IgM-RF) were evaluated before and after RA diagnosis in samples from cases (n = 214) and controls (n = 210). The timing of elevations in autoantibody concentrations relative to RA diagnosis was explored using separate mixed models for each antibody and/or isotype.

Immunogenic and inflammatory responses to citrullinated proteins are enhanced following modification with malondialdehyde-acetaldehyde adducts.

Background/objective: Malondialdehyde-acetaldehyde adducts (MAA) act as potent immune adjuvants and co-localize with citrullinated antigens in tissues effected by rheumatoid arthritis (RA). We sought to examine the role of MAA-adducts in promoting RA-related autoimmunity and inflammation.

Methods: DBA/J1 mice were immunized with human serum albumin (HSA), HSA-MAA, citrullinated HSA (HSA-Cit), or HSA-MAA-Cit with subsequent measurement of serum anti-citrullinated protein antibody (ACPA) and anti-Cit T cell responses.

Surface nano-modification by ion beam-assisted deposition alters the expression of osteogenic genes in osteoblasts.

Biomaterials with enhanced biocompatibility are favored in implant studies to improve the outcomes of total joint replacement surgeries. This study tested the hypothesis that nano-structured surfaces for orthopedic applications, produced by the ion beam-assisted deposition method, would enhance osteointegration by altering the expression of bone-associated genes in osteoblasts. The ion beam-assisted deposition technique was employed to deposit nano-films on glass or titanium substrates.

Novel Antioxidant Properties of Doxycycline.

Doxycycline (DOX), a derivative of tetracycline, is a broad-spectrum antibiotic that exhibits a number of therapeutic activities in addition to its antibacterial properties. For example, DOX has been used in the management of a number of diseases characterized by chronic inflammation. One potential mechanism by which DOX inhibits the progression of these diseases is by reducing oxidative stress, thereby inhibiting subsequent lipid peroxidation and inflammatory responses.

Antioxidant properties of citric acid interfere with the uricase-based measurement of circulating uric acid.

Background: Circulating uric acid (UA) is an important biomarker, not only in the detection and management of gout, but also in assessing the risk of related comorbidity. The impact of collection methods on clinical UA measurements has been the subject of limited study. After observing significant differences between UA concentrations of blood samples obtained by different collection tubes, we began examining the effects of exogenous tube components on measured UA concentrations.

N-Acetyl Cysteine Treatment Restores Early Phase Fracture Healing in Ethanol-Fed Rats.

Background: Fracture healing in alcoholics is delayed and often associated with infections resulting in prolonged rehabilitation. It has been reported that binge drinking of alcohol increases oxidative stress and delays fracture healing in rats, which is prevented by treatment with the antioxidant n-acetyl cysteine (NAC). Oxidative stress is a significant factor in pathologies of various organs resulting from chronic alcoholism.

Malondialdehyde-acetaldehyde antibody concentrations in rheumatoid arthritis and other rheumatic conditions.

Objective: To compare anti-malondialdehyde-acetaldehyde (MAA) antibody concentrations between rheumatoid arthritis (RA) patients and healthy and rheumatic disease controls.

Methods: Anti-MAA antibody (IgA, IgM, IgG) was measured using ELISA and banked serum from patients with RA (n = 284), osteoarthritis (OA, n = 330), spondyloarthropathy (SpA, n = 50), and systemic lupus erythematosus (SLE, n = 88) as well as healthy controls (n = 82). Anti-MAA antibody concentrations and the frequency of positivity were compared across groups.

Liver tissue metabolically transformed by alcohol induces immune recognition of liver self-proteins but not in vivo inflammation.

Precision-cut liver slices (PCLSs) provide a novel model for studies of alcoholic liver disease (ALD). This is relevant, as in vivo ethanol exposure does not appear to generate significant liver damage in ethanol-fed mice, except in the National Institute on Alcohol Abuse and Alcoholism binge model of ALD. Previous studies have shown that the two metabolites of ethanol consumption, malondialdhyde (MDA) and acetaldehyde (AA), combine to form MDA-AA (MAA) adducts, which have been correlated with the development and progression of ALD.

Malondialdehyde-Acetaldehyde (MAA) Protein Adducts Are Found Exclusively in the Lungs of Smokers with Alcohol Use Disorders and Are Associated with Systemic Anti-MAA Antibodies.

Background: Malondialdehyde (MDA) and acetaldehyde (AA) exist following ethanol metabolism and tobacco pyrolysis. As such, lungs of individuals with alcohol use disorders (AUDs) are a target for the effects of combined alcohol and cigarette smoke metabolites. MDA and AA form a stable protein adduct, malondialdehyde-acetaldehyde (MAA) adduct, known to be immunogenic, profibrotic, and proinflammatory.

Direct antioxidant properties of methotrexate: Inhibition of malondialdehyde-acetaldehyde-protein adduct formation and superoxide scavenging.

Methotrexate (MTX) is an immunosuppressant commonly used for the treatment of autoimmune diseases. Recent observations have shown that patients treated with MTX also exhibit a reduced risk for the development of cardiovascular disease (CVD). Although MTX reduces systemic inflammation and tissue damage, the mechanisms by which MTX exerts these beneficial effects are not entirely known.