The Role of Microenvironment in Preserving the Potency of Adult Porcine Pulmonary Valve Stem Cells .

Background And Objective: The potency of tissue resident stem cells is regulated primarily by inputs from the local microenvironment. Isolation of stem cells through enzymatic digestion of tissue may affect epigenetic regulation of cell fate and performance. Here we employ a non-enzymatic method to harvest and investigate tissue resident stem cells from the adult porcine pulmonary valve.

Critical Role of Coaptive Strain in Aortic Valve Leaflet Homeostasis: Use of a Novel Flow Culture Bioreactor to Explore Heart Valve Mechanobiology.

Background: Aortic valve (AV) disease presents critical situations requiring surgery in over 2% of the US population and is increasingly the reason for cardiac surgery. Throughout the AV cycle, mechanical forces of multiple types and varying intensities are exerted on valve leaflets. The mechanisms whereby forces regulate leaflet homeostasis are incompletely understood.

Reconstruction of pulmonary artery with porcine small intestinal submucosa in a lamb surgical model: Viability and growth potential.

Objectives: This study investigated the time-dependent remodeling and growth potential of porcine small intestine submucosa as a biomaterial for the reconstruction of pulmonary arteries in a lamb model.

Methods: Left pulmonary arteries were partially replaced with small intestine submucosal biomaterial in 6 lambs. Two animals each were humanely killed at 1, 3, and 6 months.

Reconstruction of pulmonary artery in a newborn using a porcine small intestinal submucosal patch.

In this case report, we evaluated cellular structure and the growth potential of a porcine small intestinal submucosal patch used for pulmonary artery augmentation in a 20-day-old newborn with pulmonary atresia. The patch was resected 2 months postoperatively due to apparent abnormal wall thickening and evaluated by histologic and immunohistologic staining.

Identification and characterization of cells with high angiogenic potential and transitional phenotype in calcific aortic valve.

Recent data suggest that angiogenesis plays an important role in the pathogenesis of valvular disease. However, the cellular mechanisms underlying this process remain unknown. This study aimed at identifying and characterizing the cellular components responsible for pathological neovascularization in calcific aortic valves (CAV).

Vascular wall resident progenitor cells: a source for postnatal vasculogenesis.

Here, we report the existence of endothelial precursor (EPC) and stem cells in a distinct zone of the vascular wall that are capable to differentiate into mature endothelial cells, hematopoietic and local immune cells, such as macrophages. This zone has been identified to be localized between smooth muscle and adventitial layer of human adult vascular wall. It predominantly contains CD34-positive (+) but CD31-negative (-) cells, which also express VEGFR2 and TIE2.

Endothelial effects of 3-hydroxyglutaric acid: implications for glutaric aciduria type I.

Infants with glutaric aciduria type 1 (GA1) are subject to intracranial vascular dysfunction. Here, we demonstrate that the disease-specific metabolite 3-hydroxyglutaric acid (3-OH-GA) inhibits basal and vascular endothelial growth factor (VEGF)-induced endothelial cell migration. 3-OH-GA affects the morphology of VEGF-induced endothelial tubes in vitro because of partial disintegration of endothelial cells.

Pro-angiogenic signaling by the endothelial presence of CEACAM1.

Here, we demonstrate the expression of carcinoembryonic antigen-related cell adhesion molecule-1 (CEACAM1) in angiogenic sprouts but not in large mother blood vessels within tumor tissue. Correspondingly, only human microvascular endothelial cells involved in in vitro tube formation exhibit CEACAM1. CEACAM1-overexpressing versus CEACAM1-silenced human microvascular endothelial cells were used in migration and tube formation assays.

Angiogenic activation of valvular endothelial cells in aortic valve stenosis.

Here, we demonstrate the angiogenic response of valvular endothelial cells to aortic valve (AV) stenosis using a new ex vivo model of aortic leaflets. Histological analysis revealed neovascularization within the cusps of stenotic but not of non-stenotic aortic valves. Correspondingly, the number of capillary-like outgrowth in 3D collagen gel was significantly higher in stenotic than in non-stenotic valves.

Cell type-specific expression of LINE-1 open reading frames 1 and 2 in fetal and adult human tissues.

The LINE-1 (L1) family of non-long terminal repeat retrotransposons is a major force shaping mammalian genomes, and its members can alter the genome in many ways. Mutational analyses have shown that coexpression of functional proteins encoded by the two L1-specific open reading frames, ORF1 and ORF2, is an essential prerequisite for the propagation of L1 elements in the genome. However, all efforts to identify ORF2-encoded proteins have failed so far.