Novel treatments for immune thrombocytopenia: targeting platelet autoantibodies.

INTRODUCTION: Immune thrombocytopenia (ITP) is an acquired autoimmune disorder characterized by low platelets and an increased risk of bleeding. Platelet autoantibodies target major platelet glycoproteins and cause Fc-mediated platelet destruction in the spleen and reticuloendothelial systems. As mechanisms of disease, platelet autoantibodies are important therapeutic targets. Neonatal Fc receptor (FcRn) antagonists are a new class of therapeutics that reduce the half-life of immunoglobulin G including pathogenic platelet autoantibodies. Spleen tyrosine kinase (Syk) inhibitors interfere with Fc-mediated platelet clearance. Bruton's tyrosine kinase (BTK) inhibitors and B-cell activating factor (BAFF) inhibitors reduce antibody production. The efficacy of these targeted therapies provides new support for the role of platelet autoantibodies in pathogenesis of ITP even these antibodies can be difficult to detect. AREAS COVERED: This review includes an in-depth exploration of the pathophysiologic mechanisms of ITP, focusing on autoantibodies. Treatments outlined in this review include a) FcRn antagonists, b) complement inhibitors, c) B-cell directed therapies such as BTK inhibitors, and anti-BAFF agents, d) Syk inhibitors, e) plasma-cell directed therapies, and f) novel cellular therapeutic products. EXPERT OPINION: Platelet autoantibodies are often elusive in ITP, yet novel treatments targeting this pathway reinforce their role in the pathogenesis of this autoimmune platelet disorder.

Single-dose oral anti-arrhythmic drugs for cardioversion of recent-onset atrial fibrillation: a systematic review and network meta-analysis of randomized controlled trials.

AIMS: Single oral dose anti-arrhythmic drugs (AADs) are used to cardiovert recent-onset atrial fibrillation (AF); however, the optimal agent is uncertain. METHODS: We performed a systematic review and network meta-analysis of randomized trials testing single oral dose AADs vs. any comparator to cardiovert AF <7 days duration. We searched MEDLINE, Embase, and CENTRAL to April 2020. The primary outcome was successful cardioversion at timepoint nearest 8 h after administration. RESULTS: From 12 712 citations, 22 trials (2320 patients) were included. Thirteen trials included patients with some degree of heart failure; 19 included patients with some degree of ischaemic heart disease vs. placebo or rate-control (32% success) at 8 h, flecainide [73%, network odds ratio (OR) 7.6, 95% credible interval (CrI) 4.4-14.0], propafenone (70%, OR 4.6, CrI 2.9-7.3), and pilsicainide (59%, OR 10.0, CrI 1.8-69.0), but not amiodarone (28%, OR 1.0, CrI 0.4-2.8) were superior. Flecainide (OR 7.5, CrI 2.6-24.0) and propafenone (OR 4.5, CrI 1.6-13.0) were superior to amiodarone; propafenone vs. flecainide did not statistically differ (OR 0.6, CrI 0.3-1.1). At longest follow-up, amiodarone was superior to placebo (OR 11.0, CrI 3.2-41.0), flecainide vs. amiodarone (OR 0.79, CrI 0.19-3.1), and propafenone vs. amiodarone (OR 0.36, CrI 0.092-1.4) were not statistically different, and flecainide was superior to propafenone (OR 2.2, CrI 1.1-4.8). Atrial and ventricular tachyarrhythmias, bradyarrhythmias, and hypotension were rare with PO AADs. CONCLUSION: Single oral dose Class 1C AADs are effective and safe for cardioversion of recent-onset AF. Flecainide may be superior to propafenone. Amiodarone is a slower acting alternative.

Incidence and recurrence of new-onset atrial fibrillation detected during hospitalization for non-cardiac surgery: a systematic review and meta-analysis.

PURPOSE: This systematic review aimed to summarize reports of the incidence and long-term recurrence of new-onset atrial fibrillation (AF) associated with non-cardiac surgery. SOURCES: We searched CENTRAL, MEDLINE and EMBASE from inception to November 2019. We included studies that reported on the incidence of new-onset perioperative AF during hospitalization for non-cardiac surgery and/or AF recurrence in such patients following discharge. Reviewers screened articles and abstracted data independently and in duplicate. We assessed study quality by appraising methodology for collecting AF history, incident AF during hospitalization, and AF recurrence after discharge. PRINCIPAL FINDINGS: From 39,233 citations screened, 346 studies that enrolled a total of 5,829,758 patients met eligibility criteria. Only 27 studies used prospective, continuous inpatient electrocardiographic (ECG) monitoring to detect incident AF. Overall, the incidence of postoperative AF during hospitalization ranged from 0.004 to 50.3%, with a median [interquartile range] of 8.7 [3.8-15.0]%. Atrial fibrillation incidence varied with type of surgery. Prospective studies using continuous ECG monitoring reported significantly higher incidences of AF than those that did not (13.9% vs 1.9%, respectively; P < 0.001). A total of 13 studies (25,726 patients) with follow-up up to 5.4 years reported on AF recurrence following hospital discharge; only one study used a prospective systematic monitoring protocol. Recurrence rates ranged from 0 to 37.3%. CONCLUSIONS: Rates of AF incidence first detected following non-cardiac surgery and long-term AF recurrence vary markedly. Differences in the intensity of ECG monitoring and type of surgery may account for this variation. TRIAL REGISTRATION: PROSPERO (CRD42017068055); registered 1 September 2017.

RéSUMé: OBJECTIF: Cette revue systématique visait à résumer les comptes rendus sur l'incidence et la récurrence à long terme de la fibrillation auriculaire (FA) de novo associée à une chirurgie non cardiaque. SOURCES: Nous avons effectué des recherches dans les bases de données CENTRAL, MEDLINE et EMBASE de leur création à novembre 2019. Nous avons inclus les études ayant examiné l'incidence de nouvelle FA périopératoire pendant l'hospitalisation pour une chirurgie non cardiaque et/ou la récurrence de la FA chez de tels patients après leur congé. Les chercheurs ont passé en revue les articles et les données extraites de manière indépendante et en double. Nous avons estimé la qualité des études en évaluant la méthodologie de collecte des antécédents de FA, de l'incident de FA pendant l'hospitalisation et de la récurrence de FA après le congé. CONSTATATIONS PRINCIPALES: Sur les 39 233 citations examinées, 346 études portant sur un total de 5 829 758 patients ont répondu à nos critères d'admissibilité. Seulement 27 études ont utilisé un monitorage électrocardiographique (ECG) continu prospectif et des patients hospitalisés pour détecter les incidents de FA. Dans l'ensemble, l'incidence de FA postopératoire pendant l'hospitalisation allait de 0,004 à 50,3 %, avec une médiane [écart interquartile] de 8,7 [3,8-15,0] %. L'incidence de fibrillation auriculaire variait en fonction du type de chirurgie. Des études prospectives utilisant un monitorage continu par ECG ont fait état d'incidences significativement plus élevées de FA que celles sans monitorage continu (13,9 % vs 1,9 %, respectivement; P < 0,001). Au total, 13 études (25 726 patients) avec un suivi allant jusqu'à 5,4 ans ont rapporté leurs données sur la récurrence de FA après le congé de l'hôpital; seule une étude a utilisé un protocole de monitorage prospectif systématique. Les taux de récurrence allaient de 0 à 37,3 %. CONCLUSION: Les taux d'incidence de nouvelle FA détectés après une chirurgie non cardiaque et la récurrence à long terme de FA varient considérablement. Les différences du degré de monitorage par ECG et le type de chirurgie pourraient expliquer cette variation. ENREGISTREMENT DE L'éTUDE: PROSPERO (CRD42017068055); enregistrée le 1er septembre 2017.

Mechanical regulation of breast cancer migration and apoptosis via direct and indirect osteocyte signaling.

Bone metastases, the migration of cancers to bone, occur in 65-80% of patients with advanced breast cancer. Metastasized cancer cells interact with cells such as the bone-resorbing osteoclasts to alter bone remodeling. Exercise, often suggested as an intervention for cancer patients, regulates bone remodeling via osteocytes. Osteocytes also signal to endothelial cells, which may affect cancer cell extravasation. Therefore, we hypothesize that mechanically stimulated osteocytes can regulate processes in breast cancer bone metastasis. To test this, we exposed osteocytes to oscillatory fluid flow in vitro using parallel-plate flow chambers. We observed that conditioned medium from flow-stimulated osteocytes increased migration (by 45%) and reduced apoptosis (by 12%) of breast cancer cells. Conditioned medium from osteoclasts conditioned in flowed osteocytes' conditioned medium reduced migration (by 47%) and increased apoptosis (by 55%) of cancer cells. Cancer cell trans-endothelial migration was reduced by 34% toward flowed osteocytes' conditioned medium. This difference was abolished with ICAM-1 or IL-6 neutralizing antibodies. Conditioned medium from endothelial cells conditioned in flowed osteocytes' conditioned medium increased cancer cell apoptosis by 29%. To summarize, this study demonstrated mechanically stimulated osteocytes' potential to affect breast cancer cells not only through direct signaling, but also through osteoclasts and endothelial cells. The anti-metastatic potential of the indirect signalings is particularly exciting since osteocytes are further away from metastasizing cancer cells than osteoclasts and endothelial cells. Future studies into the effect of bone mechanical loading on metastases and its mechanism will assist in designing cancer intervention programs that lowers the risk for bone metastases.