Liver bud transplantation in rats

2018 ◽  
Vol 71 (4) ◽  
pp. 163-169
Author(s):  
Eiji Kobayashi ◽  
Shin Enosawa
Keyword(s):  
Fetal Liver ◽  
Liver Parenchyma ◽  
Arterial Blood Flow ◽  
Silk Suture ◽  
Cell Sheets ◽  
Human Liver Tissue ◽  
Arterial Blood ◽  
Matrix Cell ◽  
Experimental Microsurgery

Abstract: Introduction: Research has made progress in organ fabrication using an extracellular matrix, cell sheets, or organoids. Human liver tissue has been constructed using a 3-dimensional (3D) bioprinter and showed evidence that an in vitro generated liver bud was reformed in a rodent liver model. This study describes the stages of development of rat fetal organs and liver structure and reviews recent progress in liver organoid transplantation. Methods: The authors developed the procedures for creating a transected plane for use in experimental microsurgery in rats. A liver lobe was fixed vertically with gauze and it was ligated with 6-0 silk suture in the cut line; the parenchyma was cut, and major vessels were ligated to create the transected plane. The ligated tissue was carefully resected. Hemostasis was not required and hepatic components remained on the transected plane. The plane was covered by omentum. Results: Using this model, we transplanted fetal liver or a 3D bioprinted liver organoid. This microsurgical method enabled creation of an intact liver parenchyma plane. No bleeding was observed. The transplanted liver components successfully engrafted on the liver. Conclusion: This method may provide an essential environment for growing liver using portal and arterial blood flow.

scholarly journals Arterial pulse wave propagation across stenoses and aneurysms: assessment of one-dimensional simulations against three-dimensional simulations and in vitro measurements

2021 ◽  
Vol 18 (177) ◽  
Author(s):  
Weiwei Jin ◽  
Jordi Alastruey
Keyword(s):  
Abdominal Aorta ◽  
Three Dimensional ◽  
Experimental Models ◽  
Arterial Blood Flow ◽  
Future Research ◽  
One Dimensional ◽  
Arterial Blood ◽  
Mean Square Errors ◽  
Pressure And Flow Waves

One-dimensional (1-D) arterial blood flow modelling was tested in a series of idealized vascular geometries representing the abdominal aorta, common carotid and iliac arteries with different sizes of stenoses and/or aneurysms. Three-dimensional (3-D) modelling and in vitro measurements were used as ground truth to assess the accuracy of 1-D model pressure and flow waves. The 1-D and 3-D formulations shared identical boundary conditions and had equivalent vascular geometries and material properties. The parameters of an experimental set-up of the abdominal aorta for different aneurysm sizes were matched in corresponding 1-D models. Results show the ability of 1-D modelling to capture the main features of pressure and flow waves, pressure drop across the stenoses and energy dissipation across aneurysms observed in the 3-D and experimental models. Under physiological Reynolds numbers ( Re ), root mean square errors were smaller than 5.4% for pressure and 7.3% for the flow, for stenosis and aneurysm sizes of up to 85% and 400%, respectively. Relative errors increased with the increasing stenosis and aneurysm size, aneurysm length and Re , and decreasing stenosis length. All data generated in this study are freely available and provide a valuable resource for future research.

scholarly journals Endothelial miR-17∼92 cluster negatively regulates arteriogenesis via miRNA-19 repression of WNT signaling

2015 ◽  
Vol 112 (41) ◽  
pp. 12812-12817 ◽  
Author(s):  
Shira Landskroner-Eiger ◽  
Cong Qiu ◽  
Paola Perrotta ◽  
Mauro Siragusa ◽  
Monica Y. Lee ◽  
...  
Keyword(s):  
Blood Flow ◽  
Wnt Signaling ◽  
Critical Role ◽  
Arterial Blood Flow ◽  
In Vivo Model ◽  
Mirna Regulation ◽  
Arterial Blood ◽  
Specific Deletion

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.

Relationship between vascular reactivity in vitro and blood flows in rats with cirrhosis

1999 ◽  
Vol 97 (3) ◽  
pp. 313-318 ◽  
Author(s):  
Dominique PATERON ◽  
Frédéric OBERTI ◽  
Pascale LEFILLIATRE ◽  
Nary VEAL ◽  
Khalid A. TAZI ◽  
...  
Keyword(s):  
Blood Flow ◽  
Vascular Reactivity ◽  
Regional Blood Flow ◽  
Arterial Blood Flow ◽  
Blood Flows ◽  
Arterial Blood ◽  
Vascular Responsiveness ◽  
Microsphere Method ◽  
Radioactive Microsphere Method

In cirrhosis there is a hyperdynamic circulation, which occurs mainly in the systemic and splanchnic regions. Using isolated-vessel models, previous studies have shown reduced aortic reactivity to vasoconstrictors in rats with cirrhosis. The aim of the present study was to evaluate and compare the vascular responsiveness to phenylephrine in arterial rings and the blood flows from different regions in rats with cirrhosis and controls. Reactivity was studied in isolated thoracic aortic, superior mesenteric arterial and carotid arterial rings from sham-operated and bile-duct-ligated rats by measuring the cumulative concentration-dependent tension induced by phenylephrine (10-9–10-4 M). Blood flows were measured by the radioactive microsphere method. In rats with cirrhosis, a significant hyporeactivity to phenylephrine was observed in both the aorta and the superior mesenteric artery compared with the corresponding arteries of normal rats. This hyporesponsiveness was corrected by Nω-nitro-l-arginine (0.1 mM). In contrast, carotid artery reactivity and the responses to Nω-nitro-l-arginine were similar in the cirrhotic and control groups. In each case, cardiac output and mesenteric arterial blood flow were significantly higher in cirrhotic than in normal rats. Cerebral blood flows were not significantly different between the two groups. In cirrhotic rats, arterial hyporeactivity may be a consequence of increased regional blood flow and increased production of nitric oxide.

An in vitro study of pressure increases during contrast injections in diagnostic cerebral angiography

2021 ◽  
pp. 159101992199609
Author(s):  
Samantha Marfoglio ◽  
Brandon Kovarovic ◽  
Wei Hou ◽  
David J Fiorella ◽  
Chander Sadasivan
Keyword(s):  
Cerebral Angiography ◽  
In Vitro Study ◽  
Vitro Study ◽  
Arterial Blood Flow ◽  
In Vivo Studies ◽  
Percentage Increase ◽  
Arterial Blood ◽  
Catheter Tip ◽  
Injection Rates

Background During diagnostic cerebral angiography, the contrast bolus injected into a vessel can cause substantial changes in baseline pressures and flows. One potential, and serious complication is the re-rupture of aneurysms due to these injections. The goals of this in vitro study were to evaluate the effect of injection conditions on intraneurysmal pressure changes during angiography. Methods A silicone replica of a complete circle of Willis model with ophthalmic, anterior communicating, and basilar tip aneurysms was connected to a physiologically accurate flow pump. Contrast injections were performed under different conditions (carotid or vertebral vessel imaging, catheter diameter, injection rate, injection time, and arterial blood flow rate) and the pressure in each aneurysm was recorded before and during each injection. The effect of injection conditions on percentage increase in aneurysm pressures was statistically assessed. Additionally, the effect of the distance between the aneurysm and the catheter-tip on aneurysmal pressures was assessed. Results Mean intraneurysmal pressures during injection (84.5 ± 10.8 mmHg) were significantly higher than pre-injection pressures (80.4 ± 10.6 mmHg, p < 0.0001). Only 3 of the 5 conditions – carotid injections, higher injection rates, and smaller catheter diameters – significantly increased intraneurysmal pressures. The catheter-tip distance showed no correlation to pressure increases. Conclusions Increasing contrast injection rates and decreasing catheter diameters are correlated to intraneurysmal pressure increases during angiography irrespective of the distance to the catheter tip. Future in vivo studies are required to confirm these findings and determine whether the amplitude of pressure increases with commonly used injection rates can be clinically detrimental.

Abstract P214: Mechanotransduction And Uterine Blood Flow In Preeclampsia- The Role Of Piezo 1 Ion Channels.

Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
Olufunke O Arishe ◽  
Vanessa Dela Justina ◽  
Fernanda B Priviero ◽  
Clinton R Webb
Keyword(s):  
Blood Flow ◽  
Vascular Remodeling ◽  
Vascular Reactivity ◽  
Small Diameter ◽  
Subsequent Development ◽  
Normal Pregnancy ◽  
Arterial Blood Flow ◽  
Pregnant Rats ◽  
Arterial Blood

Background: There is a large increase in uterine arterial blood flow during normal pregnancy. Structural and cellular adjustments occur in the uterine vasculature during pregnancy to accommodate this increased blood flow through a process is known as ‘vascular remodeling’. The etiology of preeclampsia involves aberrant placentation and vascular remodeling leading to reduced uteroplacental perfusion. However, the underlying source of the deficient vascular remodeling and the subsequent development of preeclampsia remains to be fully understood. Piezo 1 channels have been shown to be highly expressed in vascular smooth muscle cells of small-diameter arteries and play a role in the structural remodeling of the arteries. Studies have also shown that Piezo 1 is present in uterine arteries and it’s not exclusive to the endothelial cells. Hypothesis: This study tests the hypothesis that reduced Piezo 1 activity contributes to decreased uterine vascular relaxation in hypertensive pregnant rats. Methods: Hypertension was induced by treating the pregnant rats with synthetic CpG ODN (ODN 2395) via three intraperitoneal injections (100μg/rats) while the normotensive controls were treated with saline (vehicle) on the 14 th , 17th and 18 th days of pregnancy. Mean arterial pressure (MAP) was measured. In vitro vascular reactivity of uterine arterial (UA) ring segments were evaluated using isometric wire myograph system. Rings were pre-contracted with 3μM phenylephrine (PE), concentration responses of to Yoda1; a pharmacological agonist of Piezo 1 channel were compared. Statistical analysis was performed using nonlinear regression and Students’ t-test. Results: Our results show that MAP was greater in rats treated with ODN2395 vs untreated rats (112 ± 1 vs 90 ± 1 p =0.0004). Concentration-dependent relaxation responses to Yoda1 were greater in UAs of untreated rats compared to those treated with ODN2395 (EC50 0.06571 ± 0.09781 vs. 0.5774 ± 0.1187 p =0.0018). Conclusion: These results suggest that the reduced vasodilation in pregnancy-associated hypertension may be due to a reduced Piezo 1 channel activity.

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