The inflammatory burden of the complex rheumatoid arthritis (RA) disease affects several organ-systems, including rheological properties of blood and its formed elements. Red blood cells (RBCs) are constantly exposed to circulating dysregulated inflammatory molecules that are co-transported within the vasculature; and their membranes may be particularly vulnerable to the accompanying oxidative stress. In the current study, we investigate biophysical and ultrastructural characteristics of RBCs obtained from a cohort of patients using atomic force microscopy (AFM), scanning electron microscopy (SEM) and confocal microscopy (CM). Statistical analyses of AFM data showed that RA RBCs possessed significantly reduced membrane elasticity relative to that of RBCs from healthy individuals (P-value <0.0001). SEM imaging of RA RBCs revealed increased anisocytes and poikilocytes. Poikilocytes included knizocytes, stomatocytes, dacryocytes, irregularly contracted cells, and knot cells. CM imaging of several RA RBCs, spectrin, and band 3 protein networks portrayed the similar morphological profiles. Analyses of CM images confirmed changes to distribution of band-3 skeletal protein, a protein critical for gaseous exchange functions of the RBC and preventing membrane surface loss. Decreased membrane deformability impairs the RBC's capacity to adequately adapt its shape to navigate blood vessels, especially microvasculature, and this decrease is also reflected in the cell's morphology. Changes to morphology and deformability may also indicate loss of functional domains and/or pathological protein and lipid associations. These findings suggest that RA disease and/or its concomitant factors impact on the RBC and its membrane integrity with potential for exacerbating pathological cellular function, hemorheology, and cardiovascular function.
Adult rheumatoid arthritis (RA) is an autoimmune disorder affecting joints and frequently characterised by initial local and later systemic inflammation. Researchers have, for many years, traced its cause to diverse genetic, environmental and especially immunological responses that work against the body's own cells and tissues. Investigation into several of these biomarkers reveals interconnections that exist between multiple factors, which ultimately lead to specific pathologies. The goal of this paper is to highlight connections present between the major biological players long identified by researchers including more recently uncovered biomarkers in the RA repertoire and some of the pathophysiologies typically affiliated with the disease. Biomarkers reviewed, and becoming more clearly defined for RA include genetic, cytokines like tumor-necrosis factor-α (TNF-α), lymphocytes, nuclear antigens, antibodies to citrullinated peptides (anti-CPs), acute-phase proteins (APPs), microRNA, S100 proteins, platelets and erythrocytes. Some of the disease manifestations that have been connected are bone erosion, diabetes, metabolic syndrome, anemia, synovitis, felty's syndrome, extra-articular manifestations (EAMs) such as atherosclerosis, rheumatoid nodules and cardiovascular (CV) events. Several RA markers associated with malignancy have been identified in literature although there is insufficient evidence of cancer in patients. Due to the complex nature of the disease, the appearance of symptoms and markers vary amongst individuals and the connections may manifest only in part. This manuscript addresses defining factors relevant to rapid identification of pathological influences these biomolecules could exert and to the management of the disease. Each of these biological players may have its place in connecting to symptomatic pathologies and help to highlight potential targets for therapy.
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