scholarly journals 120 Blood flow is required for endothelial repair in a novel in vivo model using zebrafish embryos

Heart ◽  
2012 ◽  
Vol 98 (Suppl 1) ◽  
pp. A68.1-A68
Author(s):  
N M Quaife ◽  
T J A Chico
1997 ◽  
Vol 78 (04) ◽  
pp. 1242-1248 ◽  
Author(s):  
David E Newby ◽  
Robert A Wright ◽  
Christopher A Ludlam ◽  
Keith A A Fox ◽  
Nicholas A Boon ◽  
...  

SummaryThe effects on blood flow and plasma fibrinolytic and coagulation parameters of intraarterial substance P, an endothelium dependent vasodilator, and sodium nitroprusside, a control endothelium independent vasodilator, were studied in the human forearm circulation. At subsystemic locally active doses, both substance P (2-8 pmol/min) and sodium nitroprusside (2-8 μg/min) caused dose-dependent vasodilatation (p <0.001 for both) without affecting plasma concentrations of PAI-1, von Willebrand factor antigen or factor VIII:C activity. Substance P caused local increases in t-PA antigen and activity (p <0.001) in the infused arm while sodium nitroprusside did not. At higher doses, substance P increased blood flow and t-PA concentrations in the noninfused arm. We conclude that brief, locally active and subsystemic infusions of intraarterial substance P cause a rapid and substantial local release of t-PA which appear to act via a flow and nitric oxide independent mechanism. This model should provide a useful and selective method of assessing the in vivo capacity of the forearm endothelium to release t-PA acutely.


Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 8 ◽  
Author(s):  
Mayra Antúnez-Mojica ◽  
Andrés Rojas-Sepúlveda ◽  
Mario Mendieta-Serrano ◽  
Leticia Gonzalez-Maya ◽  
Silvia Marquina ◽  
...  

By using a zebrafish embryo model to guide the chromatographic fractionation of antimitotic secondary metabolites, seven podophyllotoxin-type lignans were isolated from a hydroalcoholic extract obtained from the steam bark of Bursera fagaroides. The compounds were identified as podophyllotoxin (1), β-peltatin-A-methylether (2), 5′-desmethoxy-β-peltatin-A-methylether (3), desmethoxy-yatein (4), desoxypodophyllotoxin (5), burseranin (6), and acetyl podophyllotoxin (7). The biological effects on mitosis, cell migration, and microtubule cytoskeleton remodeling of lignans 1–7 were further evaluated in zebrafish embryos by whole-mount immunolocalization of the mitotic marker phospho-histone H3 and by a tubulin antibody. We found that lignans 1, 2, 4, and 7 induced mitotic arrest, delayed cell migration, and disrupted the microtubule cytoskeleton in zebrafish embryos. Furthermore, microtubule cytoskeleton destabilization was observed also in PC3 cells, except for 7. Therefore, these results demonstrate that the cytotoxic activity of 1, 2, and 4 is mediated by their microtubule-destabilizing activity. In general, the in vivo and in vitro models here used displayed equivalent mitotic effects, which allows us to conclude that the zebrafish model can be a fast and cheap in vivo model that can be used to identify antimitotic natural products through bioassay-guided fractionation.


Author(s):  
Katharina Brotzmann ◽  
André Wolterbeek ◽  
Dinant Kroese ◽  
Thomas Braunbeck

Abstract Since teratogenicity testing in mammals is a particular challenge from an animal welfare perspective, there is a great need for the development of alternative test systems. In this context, the zebrafish (Danio rerio) embryo has received increasing attention as a non-protected embryonic vertebrate in vivo model. The predictive power of zebrafish embryos for general vertebrate teratogenicity strongly depends on the correlation between fish and mammals with respect to both overall general toxicity and more specific endpoints indicative of certain modes-of-action. The present study was designed to analyze the correlation between (1) effects of valproic acid and nine of its analogues in zebrafish embryos and (2) their known neurodevelopmental effects in mice. To this end, zebrafish embryos exposed for 120 h in an extended version of the acute fish embryo toxicity test (FET; OECD TG 236) were analyzed with respect to an extended list of sublethal endpoints. Particular care was given to endpoints putatively related to neurodevelopmental toxicity, namely jitter/tremor, deformation of sensory organs (eyes) and craniofacial deformation, which might correlate to neural tube defects caused by valproic acid in mammals. A standard evaluation of lethal (LC according to OECD TG 236) and sublethal toxicity (EC) merely indicated that four out of ten compounds tested in zebrafish correlate with positive results in mouse in vivo studies. A detailed assessment of more specific effects, however, namely, jitter/tremor, small eyes and craniofacial deformation, resulted in a correspondence of 75% with in vivo mouse data. A refinement of endpoint analysis from an integration of all observations into one LCx or ECx data (as foreseen by current ecotoxicology-driven OECD guidelines) to a differential evaluation of endpoints specific of selected modes-of-action thus increases significantly the predictive power of the zebrafish embryo model for mammalian teratogenicity. However, for some of the endpoints observed, e.g., scoliosis, lordosis, pectoral fin deformation and lack of movement, further experiments are required for the identification of underlying modes-of-action and an unambiguous interpretation of their predictive power for mammalian toxicity.


2009 ◽  
Vol 296 (5) ◽  
pp. R1650-R1660 ◽  
Author(s):  
Yi-Fang Wang ◽  
Yung-Che Tseng ◽  
Jia-Jiun Yan ◽  
Junya Hiroi ◽  
Pung-Pung Hwang

The thiazide-sensitive Na+-Cl− cotransporter (NCC), a member of the SLC12 family, is mainly expressed in the apical membrane of the mammalian distal convoluted tubule (DCT) cells, is responsible for cotransporting Na+ and Cl− from the lumen into DCT cells and plays a major role in the mammalian renal NaCl reabsorption. The NCC has also been reported in fish, but the functional role in fish ion regulation is yet unclear. The present study used zebrafish as an in vivo model to test the hypothesis of whether the NCC plays a role in Na+ and/or Cl− uptake mechanisms. Four NCCs were cloned, and only one of them, zebrafish (z) slc12a10.2 was found to predominately and specifically be expressed in gills. Double in situ hybridization/immunocytochemistry in zebrafish skin/gills demonstrated that the specific expression of zslc12a10.2 mRNA in a novel group of ionocytes differed from those of the previously-reported H+-ATPase-rich (HR) cells and Na+-K+-ATPase-rich (NaR) cells. Gill mRNA expression of zslc12a10.2 was induced by a low-Cl environment that stimulated fish Cl− influx, while a low-Na environment suppressed this expression. Incubation with metolazone, a specific inhibitor of the NCC, impaired both Na+ and Cl− influx in 5-day postfertilization (dpf) zebrafish embryos. Translational knockdown of zslc12a10.2 with a specific morpholino caused significant decreases in both Cl− influx and Cl− content of 5-dpf zebrafish embryos, suggesting that the operation of zNCC-like 2 results in a net uptake of Cl− in zebrafish. On the contrary, zslc12a10.2 morphants showed increased Na+ influx and content that resulted from upregulation of mRNA expressions of Na+-H+ exchanger 3b and carbonic anhydrase 15a in HR cells. These results for the first time provide in vivo molecular physiological evidence for the possible role of the NCC in the Cl− uptake mechanism in zebrafish skin/gills.


1987 ◽  
Author(s):  
J D Folts ◽  
S R Smith

Dipyridamole (Dip) is reputed to inhibit (I) platelet aggregation (PA) and acute thrombus formation (ATF) by two mechanisms including inhibiting 1.) platelet (Pt) phosphodiesterase, 2.) adenosine (A) reuptake by red cells, which should raise plasma A. Both effects should raise Pt cyclic AMP and thus be a potent platelet inhibitor (PI). Because aspirin (AS) inhibits Pt thromboxane A2 production, a synergistic (S) PI effect for ASA and Dip given together has been postulated and used in clinical trials but this S has never been shown to I ATP in any in vivo model, which reasonably mimics human arterial stenosis. We have shown that ATF followed by embolization, occurs periodically in mechanically stenosed (MS) monkey and rabbit carotid arteries, and dog (D) and pig coronary arteries (CA), causing cyclical reductions in coronary blood flow (CRF) (measured with EMF probes) and periodic acute ischemia, and that these CRF can be abolished with a variety of PI including 3.0 mg/kg of ASA. To determine if there is a S effect between ASA and Dip, in open chest D, Dip was given, 2.0 mg/kg IV to D with a MS circumflex CA and having 14±5 CRF’s per hour, due to periodic ATF; and simultaneously flow measured in an unstenosed normal LAD CA. The frequency and size of CRF’s were not changed by Dip, although ABP decreased 21±9 mm Hg and blood flow in the unstenosed LAD increased 259±47%. A low dose of ASA, 1.0 mg/kg, which by itself diminishes but does not abolish CRF’s in this model was given IV 10 min. after Dip and CRF’s continued unchanged. When a second dose of ASA 1.0 mg/kg was given IV to reach the minimum effective dose of ASA in this model, CRF were abolished in all D. Thus Dip was not effective alone or in combination with low dose ASA to I CRF in this model which simulates the patient with stenosed CA. The majority of clinical trials that show inhibition of ATF, used ASA and Dip together without 3 separate patient groups on Dip alone, ASA alone and ASA plus Dip. The widespread use of Dip with ASA to prevent ATF in man needs to be reevaluated.


2016 ◽  
Vol 50 ◽  
pp. 16-20 ◽  
Author(s):  
Sun Hee Cheong ◽  
Hye-Won Yang ◽  
Eun-Yi Ko ◽  
Ginnae Ahn ◽  
WonWoo Lee ◽  
...  

2009 ◽  
Vol 38 (3) ◽  
pp. 319-327 ◽  
Author(s):  
Ian M. Packham ◽  
Caroline Gray ◽  
Paul R. Heath ◽  
Paul G. Hellewell ◽  
Philip W. Ingham ◽  
...  

The response to hemodynamic force is implicated in a number of pathologies including collateral vessel development. However, the transcriptional effect of hemodynamic force is extremely challenging to examine in vivo in mammals without also detecting confounding processes such as hypoxia and ischemia. We therefore serially examined the transcriptional effect of preventing cardiac contraction in zebrafish embryos which can be deprived of circulation without experiencing hypoxia since they obtain sufficient oxygenation by diffusion. Morpholino antisense knock-down of cardiac troponin T2 ( tnnt2) prevented cardiac contraction without affecting vascular development. Gene expression in whole embryo RNA from tnnt2 or control morphants at 36, 48, and 60 h postfertilization (hpf) was assessed using Affymetrix GeneChip Zebrafish Genome Arrays (>14,900 transcripts). We identified 308 differentially expressed genes between tnnt2 and control morphants. One such ( CXCR4a) was significantly more highly expressed in tnnt2 morphants at 48 and 60 hpf than controls. In situ hybridization localized CXCR4a upregulation to endothelium of both tnnt2 morphants and gridlock mutants (which have an occluded aorta preventing distal blood flow). This upregulation appears to be of functional significance as either CXCR4a knock-down or pharmacologic inhibition impaired the ability of gridlock mutants to recover blood flow via collateral vessels. We conclude absence of hemodynamic force induces endothelial CXCR4a upregulation that promotes recovery of blood flow.


2015 ◽  
Vol 112 (41) ◽  
pp. 12812-12817 ◽  
Author(s):  
Shira Landskroner-Eiger ◽  
Cong Qiu ◽  
Paola Perrotta ◽  
Mauro Siragusa ◽  
Monica Y. Lee ◽  
...  

The contribution of endothelial-derived miR-17∼92 to ischemia-induced arteriogenesis has not been investigated in an in vivo model. In the present study, we demonstrate a critical role for the endothelial-derived miR-17∼92 cluster in shaping physiological and ischemia-triggered arteriogenesis. Endothelial-specific deletion of miR-17∼92 results in an increase in collateral density limbs and hearts and in ischemic limbs compared with control mice, and consequently improves blood flow recovery. Individual cluster components positively or negatively regulate endothelial cell (EC) functions in vitro, and, remarkably, ECs lacking the cluster spontaneously form cords in a manner rescued by miR-17a, -18a, and -19a. Using both in vitro and in vivo analyses, we identified FZD4 and LRP6 as targets of miR-19a/b. Both of these targets were up-regulated in 17∼92 KO ECs compared with control ECs, and both were shown to be targeted by miR-19 using luciferase assays. We demonstrate that miR-19a negatively regulates FZD4, its coreceptor LRP6, and WNT signaling, and that antagonism of miR-19a/b in aged mice improves blood flow recovery after ischemia and reduces repression of these targets. Collectively, these data provide insights into miRNA regulation of arterialization and highlight the importance of vascular WNT signaling in maintaining arterial blood flow.


Blood ◽  
2011 ◽  
Vol 118 (15) ◽  
pp. 4102-4110 ◽  
Author(s):  
Lu Wang ◽  
Panpan Zhang ◽  
Yonglong Wei ◽  
Ya Gao ◽  
Roger Patient ◽  
...  

Abstract Blood flow has long been thought to be important for vessel development and function, but its role in HSC development is not yet fully understood. Here, we take advantage of zebrafish embryos with circulation defects that retain relatively normal early development to illustrate the combinatorial roles of genetic and hemodynamic forces in HSC development. We show that blood flow is not required for initiation of HSC gene expression, but instead is indispensable for its maintenance. Knockdown of klf2a mimics the silent heart (sih/tnnt2a) phenotype while overexpression of klf2a in tnnt2a morphant embryos can rescue HSC defects, suggesting that klf2a is a downstream mediator of blood flow. Furthermore, the expression of NO synthase (nos) was reduced in klf2a knockdown embryos, and ChIP analysis showed that endogenous Klf2a is bound to the promoters of nos genes in vivo, indicating direct gene regulation. Finally, administration of the NO agonist S-nitroso N-acetylpenicillamine (SNAP) can restore HSC development in tnnt2a and klf2a morphants, suggesting that NO signaling is downstream of Klf2a which is induced by hemodynamic forces. Taken together, we have demonstrated that blood flow is essential for HSC development and is mediated by a klf2a-NO signaling cascade in zebrafish.


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