In the past decade, researchers have gained important insights on the role of bone marrow (BM)-derived cells in adult neovascularization. A subset of BM-derived cells, called endothelial progenitor cells (EPCs), has been of particular interest, as these cells were suggested to home to sites of neovascularization and neoendothelialization and differentiate into endothelial cells (ECs) in situ, a process referred to as postnatal vasculogenesis. Therefore, EPCs were proposed as a potential regenerative tool for treating human vascular disease and a possible target to restrict vessel growth in tumour pathology. However, conflicting results have been reported in the field, and the identification, characterization, and exact role of EPCs in vascular biology is still a subject of much discussion. The focus of this review is on the controversial issues in the field of EPCs which are related to the lack of a unique EPC marker, identification challenges related to the paucity of EPCs in the circulation, and the important phenotypical and functional overlap between EPCs, haematopoietic cells and mature ECs. We also discuss our recent findings on the origin of endothelial outgrowth cells (EOCs), showing that this in vitro defined EC population does not originate from circulating CD133+ cells or CD45+ haematopoietic cells.

Objective-Two types of endothelial progenitor cells (EPCs), early EPCs and late EPCs (also called endothelial outgrowth cells [EOCs]), were described in vitro previously. In this report, we dissect the phenotype of the precursor(s) that generate these cell types with focus on the markers CD34, CD133, and vascular endothelial growth factor receptor-2 (VEGFR2) that have been used to identify putative circulating endothelial precursors. We also included CD45 in the analysis to assess the relation between CD34 ϩ hematopoietic progenitors (HPC), CD34 ϩ endothelial precursors, and both in vitro generated EPC types. Addressing this issue might lead to a better understanding of the lineage and phenotype of the precursor(s) that give rise to both cell types in vitro and may contribute to a consensus on their flowcytometric enumeration. Methods and Results-Using

During the past decades, worldwide clinical and scientific interest in dry needling (DN) therapy has grown exponentially. Various clinical effects have been credited to dry needling, but rigorous evidence about its potential physiological mechanisms of actions and effects is still lacking. Research identifying these exact mechanisms of dry needling action is sparse and studies performed in an acupuncture setting do not necessarily apply to DN. The studies of potential effects of DN are reviewed in reference to the different aspects involved in the pathophysiology of myofascial triggerpoints: the taut band, local ischemia and hypoxia, peripheral and central sensitization. This article aims to provide the physiotherapist with a greater understanding of the contemporary data available: what effects could be attributed to dry needling and what are their potential underlying mechanisms of action, and also indicate some directions at which future research could be aimed to fill current voids.

Human embryonic stem cells (hESC) are pluripotent stem cells. A major challenge in the field of hESC is the establishment of specific differentiation protocols that drives hESC down a particular lineage fate. So far, attempts to generate T cells from hESC in vitro were unsuccessful. In this study, we show that T cells can be generated in vitro from hESC-derived hematopoietic precursor cells present in hematopoietic zones (HZs). These zones are morphologically similar to blood islands during embryonic development, and are formed when hESC are cultured on OP9 stromal cells.

Introduction Left bundle branch area pacing (LBBAP) aims to achieve physiological pacing by capturing the conduction system in the area of the left bundle branch. LBBAP has exclusively been performed using lumen‐less pacing leads (LLLs) with fixed helix design. This study explores the feasibility, safety, and pacing characteristics of LBBAP using stylet‐driven leads (SDLs) with an extendable helix design. Methods Patients, in which LBBAP was attempted for bradycardia or heart failure pacing indications, were prospectively enrolled at the Ghent University Hospital. LBBAP was attempted with two different systems: 1/LLL with fixed helix (SelectSecure 3830, Medtronic Inc.) delivered through a preshaped sheath (C315His Medtronic Inc.) and 2/SDL with extendable helix (Solia S60, Biotronik, SE & CO) delivered through a new delivery sheath (Selectra 3D, Biotronik). Results The study enrolled 50 patients (mean age: 70 ± 14 years, 44% females). LBBAP with SDL was successful in 20/23 (87%) patients compared with 24/27 (89%) of patients in the LLL group (p = 0.834). Screw attempts, screw implant depth, procedural, and fluoroscopy times were comparable among both groups. Acute LBBAP thresholds were low and comparable between SDL and LLL (0.5 ± 0.15 V vs. 0.4 ± 0.17 V, p = 0.251). Pacing thresholds remained low at 3 ± 2.1 months of follow up in both groups and no lead revisions were necessary. Postprocedural echocardiography revealed a septal coronary artery fistula in one patient with SDLLBBAP. Conclusion LBBAP using stylet‐driven pacing leads is feasible and yields comparable implant success to LBBAP with LLLs. LBBAP thresholds are low and comparable with both types of leads.