Off-the-Shelf Synthetic Biodegradable Grafts Transform In Situ into a Living Arteriovenous Fistula in a Large Animal Model.

Current vascular access options require frequent interventions. In situ tissue engineering (TE) may overcome these limitations by combining the initial success of synthetic grafts with long-term advantages of autologous vessels by using biodegradable grafts that transform into autologous vascular tissue at the site of implantation. Scaffolds (6 mm-Ø) made of supramolecular polycarbonate-bisurea (PC-BU), with a polycaprolactone (PCL) anti-kinking-coil, are implanted between the carotid artery and jugular vein in goats.

The effect of chronic kidney disease on tissue formation of tissue-engineered vascular grafts.

Vascular tissue engineering encompasses a single-step approach with a wide adaptive potential and true off-the-shelf availability for vascular grafts. However, a synchronized balance between breakdown of the scaffold material and neo-tissue formation is essential. Chronic kidney disease (CKD) may influence this balance, lowering the usability of these grafts for vascular access in end-stage CKD patients on dialysis.

Human Bone Marrow Mononuclear Cells Do Not Improve Limb Perfusion in the Hindlimb Ischemia Model.

Effective treatments for chronic limb-threatening ischemia are lacking. (Pre)clinical studies on administration of bone marrow (BM) mononuclear cells (MNCs) and BM-derived mesenchymal stromal cells (MSCs) have shown variable results and no studies have directly compared administration of human BM MNCs and BM MSCs in in vivo models. We studied the effect of intramuscular administration of human BM-derived MNCs and MSCs on limb perfusion in the murine hindlimb ischemia (HLI) model.

Circulating Extracellular Vesicles Contain miRNAs and are Released as Early Biomarkers for Cardiac Injury.

Plasma-circulating microRNAs have been implicated as novel early biomarkers for myocardial infarction (MI) due to their high specificity for cardiac injury. For swift clinical translation of this potential biomarker, it is important to understand their temporal and spatial characteristics upon MI. Therefore, we studied the temporal release, potential source, and transportation of circulating miRNAs in different models of ischemia reperfusion (I/R) injury.

Screen-based identification and validation of four new ion channels as regulators of renal ciliogenesis.

To investigate the contribution of ion channels to ciliogenesis, we carried out a small interfering RNA (siRNA)-based reverse genetics screen of all ion channels in the mouse genome in murine inner medullary collecting duct kidney cells. This screen revealed four candidate ion channel genes: Kcnq1, Kcnj10, Kcnf1 and Clcn4. We show that these four ion channels localize to renal tubules, specifically to the base of primary cilia.

DNA replication stress underlies renal phenotypes in CEP290-associated Joubert syndrome.

Juvenile ciliopathy syndromes that are associated with renal cysts and premature renal failure are commonly the result of mutations in the gene encoding centrosomal protein CEP290. In addition to centrosomes and the transition zone at the base of the primary cilium, CEP290 also localizes to the nucleus; however, the nuclear function of CEP290 is unknown. Here, we demonstrate that reduction of cellular CEP290 in primary human and mouse kidney cells as well as in zebrafish embryos leads to enhanced DNA damage signaling and accumulation of DNA breaks ex vivo and in vivo.

Neovascularization capacity of mesenchymal stromal cells from critical limb ischemia patients is equivalent to healthy controls.

Critical limb ischemia (CLI) is often poorly treatable by conventional management and alternatives such as autologous cell therapy are increasingly investigated. Whereas previous studies showed a substantial impairment of neovascularization capacity in primary bone-marrow (BM) isolates from patients, little is known about dysfunction in patient-derived BM mesenchymal stromal cells (MSCs). In this study, we have compared CLI-MSCs to healthy controls using gene expression profiling and functional assays for differentiation, senescence and in vitro and in vivo pro-angiogenic ability.

Increasing short-term cardiomyocyte progenitor cell (CMPC) survival by necrostatin-1 did not further preserve cardiac function.

Aims: One of the main limitations for an effective cell therapy for the heart is the poor cell engraftment after implantation, which is partly due to a large percentage of cell death in the hostile myocardium. In the present study, we investigated the utilization of necrostatin-1 (Nec-1) as a possible attenuator of cell death in cardiomyocyte progenitor cells (CMPCs).

Methods And Results: In a mouse model of myocardial infarction, survival of CMPCs 3 days after intra-myocardial injection was 39 ± 9% higher in cells pretreated with the Nec-1 compound.

Endothelial cells require miR-214 to secrete exosomes that suppress senescence and induce angiogenesis in human and mouse endothelial cells.

Signaling between endothelial cells, endothelial progenitor cells, and stromal cells is crucial for the establishment and maintenance of vascular integrity and involves exosomes, among other signaling pathways. Exosomes are important mediators of intercellular communication in immune signaling, tumor survival, stress responses, and angiogenesis. The ability of exosomes to incorporate and transfer messenger RNAs (mRNAs) encoding for "acquired" proteins or micro RNAs (miRNAs) repressing "resident" mRNA translation suggests that they can influence the physiological behavior of recipient cells.

Lack of haptoglobin results in unbalanced VEGFα/angiopoietin-1 expression, intramural hemorrhage and impaired wound healing after myocardial infarction.

Decreased haptoglobin (Hp) functionality due to allelic variations is associated with worsened outcome in patients after myocardial infarction (MI). However, mechanisms through which haptoglobin deficiency impairs cardiac repair remain to be elucidated. In the present study, we identified novel molecular alterations mediated by Hp involved in early and late cardiac repair responses after left coronary artery ligation in Hp(-/-) and wild-type (WT) mice.

Inhibition of RIP1-dependent necrosis prevents adverse cardiac remodeling after myocardial ischemia-reperfusion in vivo.

Accumulating evidence indicates that programmed necrosis plays a critical role in cell death during ischemia-reperfusion. Necrostatin-1 (Nec-1), a small molecule capable of inhibiting a key regulator of programmed necrosis (RIP1), was shown to prevent necrotic cell death in experimental models including cardiac ischemia. However, no functional follow-up was performed and the action of Nec-1 remains unclear.

ACE Inhibition in Anti-Thy1 Glomerulonephritis Limits Proteinuria but Does Not Improve Renal Function and Structural Remodeling.

Background/aims: ACE inhibitor (ACE-I) treatment effectively inhibits proteinuria and ameliorates the course of various renal diseases. In experimental glomerulonephritis, however, angiotensin II (AngII) infusion has also been shown to be renoprotective. We evaluated the long-term (28 days) course of anti-Thy1 glomerulonephritis in animals with suppressed AngII formation by ACE-I treatment.

Evaluation of infarcted murine heart function: comparison of prospectively triggered with self-gated MRI.

Measurement of cardiac function is often performed in mice after, for example, a myocardial infarction. Cardiac MRI is often used because it is noninvasive and provides high temporal and spatial resolution for the left and right ventricle. In animal cardiac MRI, the quality of the required electrocardiogram signal is variable and sometimes deteriorates over time, especially with infarcted hearts or cardiac hypertrophy.

Modulation of TGF-β/BMP-6 expression and increased levels of circulating smooth muscle progenitor cells in a type I diabetes mouse model.

Background: Diabetic patients experience exaggerated intimal hyperplasia after endovascular procedures. Recently it has been shown that circulating smooth muscle progenitor cells (SPC) contribute to intimal hyperplasia. We hypothesized that SPC differentiation would be increased in diabetes and focused on modulation of TGF-β/BMP-6 signaling as potential underlying mechanism.

Improvement of mouse cardiac function by hESC-derived cardiomyocytes correlates with vascularity but not graft size.

Transplantation of human embryonic stem cell-derived cardiomyocytes (hESC-CM) has been shown to improve the function of the rodent heart 1 month after myocardial infarction (MI). However, the mechanistic basis and optimal delivery strategies are unclear. We investigated the influence of the number of injected cells, resulting graft size, and possible paracrine mechanisms in this process.

Human cardiomyocyte progenitor cell transplantation preserves long-term function of the infarcted mouse myocardium.

Aims: Recent clinical studies revealed that positive results of cell transplantation on cardiac function are limited to the short- and mid-term restoration phase following myocardial infarction (MI), emphasizing the need for long-term follow-up. These transient effects may depend on the transplanted cell-type or its differentiation state. We have identified a population of cardiomyocyte progenitor cells (CMPCs) capable of differentiating efficiently into beating cardiomyocytes, endothelial cells, and smooth muscle cells in vitro.

Targeted deletion of nuclear factor kappaB p50 enhances cardiac remodeling and dysfunction following myocardial infarction.

Myocardial infarction is commonly complicated by left ventricular remodeling, a process that leads to cardiac dilatation, congestive heart failure and death. The innate immune system plays a pivotal role in the remodeling process via nuclear factor (NF)-kappaB activation. The NF-kappaB transcription factor family includes several subunits (p50, p52, p65, c-Rel, and Rel B) that respond to myocardial ischemia.

Amelioration of anti-Thy1-glomerulonephritis by PPAR-gamma agonism without increase of endothelial progenitor cell homing.

Impaired glomerular endothelial integrity is pivotal in various renal diseases and depends on both the degree of glomerular endothelial injury and the effectiveness of glomerular endothelial repair. Glomerular endothelial repair is, in part, mediated by bone marrow-derived endothelial progenitor cells. Peroxisome proliferator activated receptor-gamma (PPAR-gamma) agonists have therapeutic actions independent of their insulin-sensitizing effects, including enhancement of endothelial progenitor cell function and differentiation.

Human embryonic stem cell-derived cardiomyocytes survive and mature in the mouse heart and transiently improve function after myocardial infarction.

Regeneration of the myocardium by transplantation of cardiomyocytes is an emerging therapeutic strategy. Human embryonic stem cells (HESC) form cardiomyocytes readily but until recently at low efficiency, so that preclinical studies on transplantation in animals are only just beginning. Here, we show the results of the first long-term (12 weeks) analysis of the fate of HESC-derived cardiomyocytes transplanted intramyocardially into healthy, immunocompromised (NOD-SCID) mice and in NOD-SCID mice that had undergone myocardial infarction (MI).

Proliferation and differentiation of bovine type A spermatogonia during long-term culture.

The present study was aimed at developing a method for long-term culture of bovine type A spermatogonia. Testes from 5-mo-old calves were used, and pure populations of type A spermatogonia were isolated. Cells were cultured in minimal essential medium (MEM) or KSOM (potassium-rich medium prepared according to the simplex optimization method) and different concentrations of fetal calf serum (FCS) for 2-4 wk at 32 degrees C or 37 degrees C.

Development of a cryopreservation protocol for type A spermatogonia.

The aim of this study was to develop a cryopreservation protocol for type A spermatogonia. Testes from 5- to 7-month-old calves were collected, and type A spermatogonia were isolated using two-step enzymatic digestion and Percoll separation. Cells were resuspended in minimum essential medium (MEM) supplemented with 1% bovine serum albumin (BSA) in a final concentration of 6 x 10(6) per mL, and the effects of different cryoprotectants and freezing protocols were tested.