Fragments Of Blood Vessels Research Articles

Integrin-alpha-6+ Candidate stem cells are responsible for whole body regeneration in the invertebrate chordate Botrylloides diegensis

Colonial ascidians are the only chordates able to undergo whole body regeneration (WBR), during which entire new bodies can be regenerated from small fragments of blood vessels. Here, we show that during the early stages of WBR in Botrylloides diegensis, proliferation occurs only in small, blood-borne cells that express integrin-alpha-6 (IA6), pou3 and vasa. WBR cannot proceed when proliferating IA6+ cells are ablated with Mitomycin C, and injection of a single IA6+ Candidate stem cell can rescue WBR after ablation. Lineage tracing using EdU-labeling demonstrates that donor-derived IA6+ Candidate stem cells directly give rise to regenerating tissues. Inhibitors of either Notch or canonical Wnt signaling block WBR and reduce proliferation of IA6+ Candidate stem cells, indicating that these two pathways regulate their activation. In conclusion, we show that IA6+ Candidate stem cells are responsible for whole body regeneration and give rise to regenerating tissues.

Numerical and experimental analysis of balloon angioplasty impact on flow hemodynamics improvement

The paper focuses on the numerical and experimental evaluation of the fluid flow inside chosen fragments of blood vessels. In the first stage of the study, the experimental tests were conducted using a research test stand, designed to be used in this evaluation. The study evaluated the blood flow through a silicone vessel with an implanted coronary stent. The PIV method was used in order to visualize the flow vectors inside a silicone vessel. Deformed vessel geometry implemented for computational fluid dynamics purposes was obtained owing to a non-linear simulation of the stent expansion (angioplasty process) in a silicone vessel. Additionally, a vessel model with a statistical 55% area stenosis and an irregular real vessel with an atherosclerotic plaque were also subjected to analysis from the hemodynamic flow point of view. A vessel with a statistical stenosis was also used to simulate the angioplasty process, which resulted in obtaining a flow domain for the vessel with an atherosclerotic plaque after the stent implantation. For each case, distributions of parameters such as OSI or TAWSS were also analyzed and discussed. The areas of low TAWSS values appear close to the stent struts. Stents with increased diameters, compared to the normal vessel diameter, create a higher risk of occurrence of the areas with low WSS values. Excessive stent deformation can cause inflammation by injuring the vessel and can initiate the restenosis and thrombotic phenomena through the increased vessel diameter.

Expression and distribution of acyl-CoA thioesterases in the white adipose tissue of rats

Acyl-CoA thioesterases (Acots) are enzymes that catalyze the hydrolysis of fatty acyl-CoAs to free fatty acids and coenzyme A, and have the potential to regulate the intracellular levels of these molecules. In this study, we show that a cytosolic isoform, Acot1, is expressed and distributed in immature adipocytes located in the perivascular region of the white adipose tissue (WAT) of rats. Immunoblot analyses detected Acot1 in all of the WATs examined, while immunohistochemistry revealed positively stained layered structures surrounding the adventitia of blood vessels in the subcutaneous WAT. When the subcutaneous WAT was digested with collagenase and centrifuged, Acot1 was recovered in the stromal vascular fraction (SVF), and not in the large mature adipocytes. In the SVF, undigested cells attached to short tubular fragments of blood vessels showed positive immunostaining, as well as a proportion of the dispersed cells. These fibroblast-like cells contained fine particulate lipid droplets, stained by oil-red O dye, in their cytoplasm, or expressed fatty acid-binding protein 4, an adipocyte marker. After induction of adipocyte differentiation following a 15-day preculture without insulin, the dedifferentiated cells showed increased Acot1 expression with a diffuse distribution throughout the cytosol. These findings suggest that Acot1 expression is transiently upregulated at an early stage of adipocyte maturation, possibly to maintain cytosolic acyl-CoAs below a certain level until the cells acquire their full capability for fat storage.

Cell signaling and transcription factor genes expressed during whole body regeneration in a colonial chordate.

BackgroundThe restoration of adults from fragments of blood vessels in botryllid ascidians (termed whole body regeneration [WBR]) represents an inimitable event in the chordates, which is poorly understood on the mechanistic level.ResultsTo elucidate mechanisms underlying this phenomenon, a subtracted EST library for early WBR stages was previously assembled, revealing 76 putative genes belonging to major signaling pathways, including Notch/Delta, JAK/STAT, protein kinases, nuclear receptors, Ras oncogene family members, G-Protein coupled receptor (GPCR) and transforming growth factor beta (TGF-β) signaling. RT-PCR on selected transcripts documented specific up-regulation in only regenerating fragments, pointing to a broad activation of these signaling pathways at onset of WBR. The followed-up expression pattern of seven representative transcripts from JAK/STAT signaling (Bl-STAT), the Ras oncogene family (Bl-Rap1A, Bl-Rab-33), the protein kinase family (Bl-Mnk), Bl-Cnot, Bl-Slit and Bl-Bax inhibitor, revealed systemic and site specific activations during WBR in a sub-population of circulatory cells.ConclusionWBR in the non-vertebrate chordate Botrylloides leachi is a multifaceted phenomenon, presided by a complex array of cell signaling and transcription factors. Above results, provide a first insight into the whole genome molecular machinery of this unique regeneration process, and reveal the broad participation of cell signaling and transcription factors in the process. While regeneration involves the participation of specific cell populations, WBR signals are systemically expressed at the organism level.

From One to Many and Back Again: A Systemic Signal Triggers Tunicate Regeneration

From One to Many and Back Again: A Systemic Signal Triggers Tunicate Regeneration

W11.279 The high deposition of free cholesterol from a lipid microemulsion in fragments of blood vessels from patients with coronary atherosclerotic disease inversely correlates with HDL transfer activity

W11.279 The high deposition of free cholesterol from a lipid microemulsion in fragments of blood vessels from patients with coronary atherosclerotic disease inversely correlates with HDL transfer activity

W11.279 The high deposition of free cholesterol from a lipid microemulsion in fragments of blood vessels from patients with coronary atherosclerotic disease inversely correlates with HDL transfer activity

W11.279 The high deposition of free cholesterol from a lipid microemulsion in fragments of blood vessels from patients with coronary atherosclerotic disease inversely correlates with HDL transfer activity

3P-0756 Deposition of cholesterol from a lipid microemulsion in fragments of blood vessels excised from patients during coronary bypass surgery

3P-0756 Deposition of cholesterol from a lipid microemulsion in fragments of blood vessels excised from patients during coronary bypass surgery

Vascular endothelial growth factor and its receptors in normal human testicular tissue

Expression of vascular endothelial growth factor (VEGF), also known as vascular permeability factor (VPF), and its receptors Flt-1 and KDR (Flk-1 in mouse) and their localization in the human testis were analyzed by means of reverse transcriptase-polymerase chain reaction (RT-PCR), Western blotting and immunohistochemistry. VEGF mRNA was detected in the human testicular tissue and in fragments of seminiferous tubules by means of RT-PCR, while fragments of blood vessels isolated from testes were negative. Western blotting procedure using a specific VEGF antibody, revealed two protein bands corresponding to 24 and 49 kDa in the extracts prepared from the whole testis and in the seminiferous tubules while no such bands were found in isolated fragments of human testicular blood vessels. Also immunohistochemically, human testicular blood vessels show no VEGF immunoreactivity, while Leydig cells and Sertoli cells were positive. The mRNA of the VEGF receptor Flt-1 was found to be expressed in human testicular tissue, in isolated fragments of testicular blood vessels and in seminiferous tubules as determined by RT-PCR procedure. In accordance with these results, the Flt-1 protein was immunohistochemically localized in Leydig, Sertoli and perivascular cells. Endothelial cells of certain segments of human testicular microvasculature also stained positive for Flt-1. Expression of VEGF receptor, KDR, could be demonstrated in human testicular tissue, in isolated seminiferous tubules and in isolated fragments of human testicular blood vessels by means of RT-PCR. Immunohistochemically, the KDR protein was localized in endothelial cells and perivascular cells of capillaries within the lamina propria of seminiferous tubules. Leydig cells and Sertoli cells show KDR immunoreactivity, too. Thus we demonstrate the presence of both types of VEGF receptors Flt-1 and KDR on Leydig as well as on Sertoli cells which are normal non-endothelial cells, suggesting hitherto unrecognized and novel functions for such receptors. The results obtained permit us to suggest VEGF as a paracrine mitogenic and angiogenic factor, responsible for modulating the capillarization of the human testicular tissue and maintaining the functions of testicular microvasculature. VEGF may also influence the permeability of capillaries passing through the groups of Leydig cells and those localized within the lamina propria of human seminiferous tubules. The differences in the expression pattern of the VEGF receptors in the human testicular tissue probably reflect different VEGF effects in different compartments of human testis.

Alanine uptake by the endothelium of canine blood vessels and by the vessels of human umbilical cord

In order to determine whether the endothelium of vascular wall fragments possesses an active uptake mechanism for alanine identical to the one present in endothelial cells in tissue culture samples of canine aorta, carotid artery and vena cava, human umbilical cord vessels, were incubated in vitro in the presence of labelled alanine. In a series of experiments, it was observed that all the tissues investigated accumulated a significant amount of this substrate against a concentration gradient, and that the accumulation was saturable in the presence of sodium. This uptake was sodium-dependent, was significantly inhibited by ouabain and was greatly reduced under anoxic conditions. Finally, the uptake was completely abolished by prior mechanical or osmotic destruction of the intima. In conclusion, the very reproducible measurement of active alanine uptake in fragments of blood vessels may be a valuable method of evaluating the integrity of the endothelium.

The fate and fine structure of fragments of blood vessels in CNS tissue cultures.

Explants from spinal cord, brain stem, cerebellum and cerebral cortex of 5–18 weeks old human embryos and newborn rats were cultivated for 2–30 days. Most of the blood vessel fragments in the explant showed a rather normal structure of their wall even after 30 days in vitro. However, the number of small vessels was reduced. The lumen of most vessels was not collapsed and in some cases filled with cell debris. The endothelial cells remained connected by terminal bars, contained many vesicles and vacuoles of varying size and osmiophilic inclusions of cell debris. While in large vessels the endothelium was always present, in some small vessels near the edge of the explant it was absent. Here, glial endfeet made contact with a basal lamina, which enclosed varying amounts of cell debris. Pericytes were rarely observed after more than 10 days in vitro. Although the perivascular astroglial sheath disintegrated during the first few days in vitro, it was reconstructed and, after about 10 days in vitro, became more complete and differentiated than it was at the time of explantation. Many glial endfeet contained aggregated osmiophilic inclusions. At these sites the perivascular glial sheath and the adhering basal lamina often were discontinuous. The basal laminae were well developed, but disintegrated where the glial sheath was discontinuous. It is concluded that in vitro vessel fragments may be preserved without normal function and basal laminae survive without endothelium.