Extracellular vesicles are membranous particles, ranging from 30 nm to 10 µm in diameter, which are released by nearly all cell types to aid in intercellular communication. These complex vesicles carry a multitude of signaling moieties from their cell of origin, such as proteins, lipids, cell surface receptors, enzymes, cytokines, metabolites, and nucleic acids. A growing body of evidence suggests that in addition to delivering cargos into target cells to facilitate intercellular communication, extracellular vesicles may also play roles in such processes as cell differentiation and proliferation, angiogenesis, stress response, and immune signaling. As these vesicles have natural biocompatibility, stability in circulation, low toxicity, and low immunogenicity, and serve as efficient carriers of molecular cargos, these nanoparticles are ideal therapeutic candidates for regenerative medicine. Exploring and identifying the homeostatic functions of extracellular vesicles may facilitate the development of new regenerative therapies. In this review, we summarize the wound healing process, difficulties in stem cell therapies for regenerative medicine, and the applications of mesenchymal stromal cell‐derived extracellular vesicles in improving and accelerating the wound healing process.

Background:Systemic lupus erythematosus (SLE) is a multifaceted disease, and its diagnosis may be challenging. A blood test for the diagnosis of SLE, the Avise Lupus test, has been recently commercialized and validated in clinical studies.Objectives:To evaluate the use of the Avise Lupus test by community rheumatologists.Methods:The study is a longitudinal, case-control, retrospective review of medical charts. Cases had a positive test result, and controls had a negative result; all patients were anti-nuclear antibodies (ANA) positive but negative for SLE-specific autoantibodies. Features of SLE, diagnosis, and medications at two time points were recorded.Results:Twenty of the 23 cases (87%) and 4 of the 23 controls (17%) were diagnosed with SLE (sensitivity=83%; specificity=86%). More cases than controls (43% vs. 17%) fulfilled 4 American College of Rheumatology (ACR) classification criteria of SLE. Sensitivity of the test was significantly higher than the ACR score (83% vs. 42%, p=0.006). A higher percentage of patients who met the classification criteria had elevated cell-bound complement activation products (CB-CAPs) compared to patients who did not. Anti-rheumatic medications were used in a higher percentage of cases than controls (83% vs. 35% at baseline, p=0.002), suggesting that cases were treated more aggressively early on.Conclusion:A positive Avise Lupus test result aids in formulating a SLE diagnosis when diagnosis based on standard-of-care tests and clinical features may be challenging, and impacts patient management. Prospective studies will be performed to better evaluate the clinical utility of the test and of CB-CAPs as biomarkers of SLE.

Tumor necrosis factor inhibitor (TNFi) therapies are often the first biologic therapy used to treat rheumatoid arthritis (RA) patients. However, a substantial fraction of patients do not respond adequately to TNFi therapies. A test with the ability to predict response would inform therapeutic decision-making and improve clinical and financial outcomes. A 32-question decision-impact survey was conducted with 248 rheumatologists to gauge the perceived clinical utility of a novel test that predicts inadequate response to TNFi therapies in RA patients. Participants were informed about the predictive characteristics of the test and asked to indicate prescribing decisions based on four result scenarios. Overall, rheumatologists had a favorable view of the test: 80.2% agreed that it would improve medical decision-making, 92.3% said it would increase their confidence when making prescribing decisions, and 81.5% said it would be useful when considering TNFi therapies. Rheumatologists would be more likely to prescribe a TNFi therapy when the test reported that no signal of non-response was detected (79.8%) and less likely to prescribe a TNFi therapy when a signal of non-response was detected (11.3%–25.4%). Rheumatologists (84.7%) agreed that payers should provide coverage for such a test. This study shows that rheumatologists support the clinical need for a test to predict inadequate response to TNFi therapies. Test results were perceived to lead to changes in prescribing behaviors as results instill confidence in the ordering rheumatologist.