Small-vessel and medium-vessel vasculitis

Understanding exosomes: Part 2-Emerging leaders in regenerative medicine

Exosomes are the smallest subset of extracellular signaling vesicles secreted by most cells with the ability to communicate with other tissues and cell types over long distances. Their use in regenerative medicine has gained tremendous momentum recently due to their ability to be utilized as therapeutic options for a wide array of diseases/conditions. Over 5000 publications are currently being published yearly on this topic, and this number is only expected to dramatically increase as novel therapeutic strategies continue to be developed. Today exosomes have been applied in numerous contexts including neurodegenerative disorders (Alzheimer's disease, central nervous system, depression, multiple sclerosis, Parkinson's disease, post-traumatic stress disorders, traumatic brain injury, peripheral nerve injury), damaged organs (heart, kidney, liver, stroke, myocardial infarctions, myocardial infarctions, ovaries), degenerative processes (atherosclerosis, diabetes, hematology disorders, musculoskeletal degeneration, osteoradionecrosis, respiratory disease), infectious diseases (COVID-19, hepatitis), regenerative procedures (antiaging, bone regeneration, cartilage/joint regeneration, osteoarthritis, cutaneous wounds, dental regeneration, dermatology/skin regeneration, erectile dysfunction, hair regrowth, intervertebral disc repair, spinal cord injury, vascular regeneration), and cancer therapy (breast, colorectal, gastric cancer and osteosarcomas), immune function (allergy, autoimmune disorders, immune regulation, inflammatory diseases, lupus, rheumatoid arthritis). This scoping review is a first of its kind aimed at summarizing the extensive regenerative potential of exosomes over a broad range of diseases and disorders.

Recent advances in Extracellular Vesicles and their involvements in vasculitis

Systemic vasculitis is a heterogeneous group of multisystem autoimmune disorders characterized by inflammation of blood vessels. Although many progresses in diagnosis and immunotherapies have been achieved over the past decades, there are still many unanswered questions about vasculitis from pathological understanding to more advanced therapies. Extracellular vesicles (EVs) are double-layer phospholipid membrane vesicles harboring various cargoes. EVs can be classified into exosomes, microvesicles (MVs), and apoptotic bodies depending on their size and origin of cellular compartment. EVs can be released by almost all cell types and may be involved in physical and pathological processes including inflammation and autoimmune responses. In systemic vasculitis, EVs may have pathogenic involvement in inflammation, autoimmune responses, thrombosis, endothelium injury, angiogenesis and intimal hyperplasia. EV-associated redox reaction may also be involved in vasculitis pathogenesis by inducing inflammation, endothelial injury and thrombosis. Additionally, EVs may serve as specific biomarkers for diagnosis or monitoring of disease activity and therapeutic efficacy, i.e. AAV-associated renal involvement. In this review, we have discussed the recent advances of EVs, especially their roles in pathogenesis and clinical involvements in vasculitis.

Anaesthetic management of a patient with eosinophilic granulomatosis with polyangiitis for internal fixation of a fractured femur

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare disease with an estimated annual incidence of 0.5-6.8 per million. It is characterised by necrotising vasculitis with multiorgan eosinophilic infiltration. Pulmonary manifestations are the most common presentation of EGPA, and cardiac complications are the most common cause of death. Anaesthetic management of EGPA is challenging due to perioperative pulmonary complications, multiorgan involvement and greater risk of cholinesterase enzyme deficiency. We are reporting the anaesthetic management of a 58-year-old woman, diagnosed with EGPA 3 years ago, who underwent urgent intramedullary nail insertion for a femur fracture. The anaesthetic technique comprised femoral nerve block and spinal anaesthesia, thereby avoiding (1) the need for upper airway manipulation, (2) potential adverse effects of anticholinesterase drugs (for reversal of neuromuscular blockade) and (3) histamine release associated with morphine administration perioperatively. Surgery and anaesthesia were uneventful.

Extracellular vesicles in autoimmune vasculitis - Little dirts light the fire in blood vessels

Systemic vasculitis is diverse group of autoimmune disorders which are characterized by inflammation of blood vessel walls with deep aching and burning pain. Their underlying etiology and pathophysiology still remain poorly understood. Extracellular vesicles (EVs), including exosomes, microvesicles (MVs), and apoptotic bodies, are membrane vesicular structures that are released either during cell activation, or when cells undergo programmed cell death, including apoptosis, necroptosis, and pyroptosis. Although EVs were thought as cell dusts, but now they have been found to be potently active since they harbor bioactive molecules, such as proteins, lipids, nucleic acids, or multi-molecular complexes. EVs can serve as novel mediators for cell-to-cell communications by delivery bioactive molecules from their parental cells to the recipient cells. Earlier studies mainly focused on MVs budding from membrane surface. Recent studies demonstrated that EVs may also carry molecules from cytoplasm or even from nucleus of their parental cells, and these EVs may carry autoantigens and are important in vasculitis. EVs may play important roles in vasculitis through their potential pathogenic involvements in inflammation, autoimmune responses, procoagulation, endothelial dysfunction/damage, angiogenesis, and intimal hyperplasia. EVs have also been used as specific biomarkers for diagnostic use or disease severity monitoring. In this review, we have focused on the aspects of EV biology most relevant to the pathogenesis of vasculitis, discussed their perspective insights, and summarized the exist literature on EV relevant studies in vasculitis, therefore provides an integration of current knowledge regarding the novel role of EVs in systemic vasculitis.

Leukocyte chemoattractant receptors in human disease pathogenesis

Combinations of leukocyte attractant ligands and cognate heptahelical receptors specify the systemic recruitment of circulating cells by triggering integrin-dependent adhesion to endothelial cells, supporting extravasation, and directing specific intratissue localization via gradient-driven chemotaxis. Chemoattractant receptors also control leukocyte egress from lymphoid organs and peripheral tissues. In this article, we summarize the fundamental mechanics of leukocyte trafficking, from the evolution of multistep models of leukocyte recruitment and navigation to the regulation of chemoattractant availability and function by atypical heptahelical receptors. To provide a more complete picture of the migratory circuits involved in leukocyte trafficking, we integrate a number of nonchemokine chemoattractant receptors into our discussion. Leukocyte chemoattractant receptors play key roles in the pathogenesis of autoimmune diseases, allergy, inflammatory disorders, and cancer. We review recent advances in our understanding of chemoattractant receptors in disease pathogenesis, with a focus on genome-wide association studies in humans and the translational implications of mechanistic studies in animal disease models.

Vascular arteritides in women

The vasculitides are multiple clinical disease states that are characterized by inflammation of the wall of blood vessels. They are typically classified by the size of the vessel that is affected. Some of the vasculitides are more commonly identified in women, such as the large-vessel vasculitides. In addition, the incidence of some of the medium and small-vessel vasculitides in women has increased during the past several decades. These inflammatory conditions specifically affecting women will be reviewed here. The implications that pregnancy may have on various vasculitides will also be highlighted.

Recent aspects of vasculitis and future direction

Vasculitis is pathologically identified as specific cellular inflammation, vessel destruction, and tissue necrosis. Current classifications of vasculitis such as the Chapel Hill Classification (CHCC) and American College of Rheumatology (ACR) guidelines are not sufficiently adequate for clinicians to diagnose vasculitis. The biomarkers that are currently in clinical use such as PR3-ANCA and MPO-ANCA, only help in diagnosing small vessel vasculitis and their sensitivity and specificity are not sufficient. However, recent developments related to the pathogenesis and etiopathogenesis of vasculitis have the potential to contribute to new and improved biomarkers. The determination of diverse roles of ANCA and synergistic effects of infection, genetic, environmental factors and drugs on pathogenesis is quite important. The demonstration of a new autoantibody directed to hLAMP-2 and the resemblance to some microbial structures, in addition to the determination of the possible roles of hepatitis B and C on vasculitis are important findings. These hints may lead to new biomarker developments, providing a better method to diagnose vasculitis. The evidence on T cell immunity as circulatory and lesional will likely contribute to the development of new drugs for vasculitis.

Churg-Strauss angiitis

Churg-Strauss angiitis or syndrome (CSA) is defined as an eosinophil-rich and granulomatous inflammation involving the respiratory tract, and necrotising vasculitis affecting small- to medium-sized vessels, and is associated with asthma and eosinophilia. It is usually classified among the so-called anti-neutrophil antibody (ANCA)-associated systemic vasculitides (AASVs) because of its clinical and pathological features that overlap with those of the other AASVs. However, two recent studies on large cohorts of patients have found that ANCAs, usually P-ANCAs/MPO-ANCAs, were present in only 38% of patients. Moreover, the ANCA status was shown to segregate with clinical phenotype. ANCA-positive patients were significantly more likely to have disease manifestations associated with small-vessel vasculitis, including necrotising glomerulonephritis, mononeuritis and purpura, whereas ANCA-negative cases were significantly more likely to have cardiac and lung involvement. Vasculitis was documented less frequently in histological specimens from ANCA-negative patients in comparison with ANCA-positive ones. These findings have led to postulate the predominance of distinct pathogenetic mechanisms in the two subsets of patients: an ANCA-mediated process in ANCA-positive patients and tissue infiltration by eosinophils with subsequent release of toxic product in ANCA-negative cases. Preliminary results suggest that ANCA-positive and ANCA-negative patients also might have a different genetic background. Corticosteroids remain the cornerstone of the initial treatment of CSA. The addition of cyclophosphamide is indicated in treatment of patients with poor-prognosis factors or in patients without poor-prognosis factors but those that are prone to relapses. The length of the maintenance therapy remains to be established. However, the vast majority of patients require long-term corticosteroids treatment to control asthma.

Translational mini-review series on immunology of vascular disease: mechanisms of vascular inflammation and remodelling in systemic vasculitis

Vessel walls are the primary inflammatory sites in systemic vasculitides. In most cases the initiating event is unknown, and a self-sustaining circuit attracts and activates inflammatory leucocytes in the wall of vessels of various size and anatomical characteristics. Recent studies have revealed homeostatic roles of vascular inflammation and have identified the action of humoral innate immunity, in particular injury-associated signals and acute phase proteins, on the activation of circulating leucocytes, platelets and endothelial cells. These advances have provided clues to the molecular mechanisms underlying the vicious circle that maintains and amplifies vessel and tissue injury.