Effect of Exogenous Angiotensin-II on Local Blood Flow in Kidneys with Neoplasm: Experiments in the rat

Tvete, Svein; Elsayed, E.A.; Clausen, G.

doi:10.3109/02841868109130432

Cited by 9 publications

(3 citation statements)

References 6 publications

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“…It is known that infusion of Ang-II while increasing blood pressure reduces local blood flow [42]. To investigate whether chronic Ang-II infusion altered regional blood flow to the kidney, we used laser Doppler flowmetry to measure the flow across renal cortex.…”

Section: Discussionmentioning

confidence: 99%

Angiotensin-II induced hypertension and renovascular remodelling in tissue inhibitor of metalloproteinase 2 knockout mice

Pushpakumar

Kundu

Pryor

et al. 2013

Journal of Hypertension

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Sustained hypertension induces renovascular remodeling by altering extracellular matrix (ECM) components. Matrix metalloproteinases (MMPs) are Zn-dependent enzymes that regulate ECM turnover in concert with their inhibitors, tissue inhibitors of metalloproteinases, TIMPs. Increased MMP-2 & -9 have been implicated in hypertensive complications; however, the contribution of individual MMPs/TIMPs in renal remodeling has not been fully elucidated. The purpose of this study was to determine the effect of TIMP2 deficiency and thus MMP-2 on Ang-II induced renal remodeling. C57BL/6J (WT) and TIMP2 knockout mice were infused with Angiotensin-II (Ang-II) at 250 ng. kg-1. min-1 for 4 weeks. Blood pressure was measured weekly and end-point laser Doppler flowmetry was done to assess cortical blood flow. Immunohistochemical staining was performed for collagen and elastin analyses. The activity of MMP-9, and -2 was determined by Gelatin zymography. Ang-II induced similar elevation in mean blood pressure in TIMP2-/- and WT mice. In TIMP2-/- mice, Ang-II treatment was associated with a greater reduction in renal cortical blood flow and barium angiography demonstrated decreased vascular density compared to Ang-II treated WT mice. Peri-glomerular and vascular collagen deposition was increased and elastin content was decreased causing increased wall-to-lumen ratio in TIMP2-/- mice compared to WT mice receiving Ang-II. Ang-II increased the expression and activity of MMP-9 predominantly in TIMP2-/- mice than in WT mice. These results suggest that TIMP2 deficiency exacerbates renovascular remodeling in agonist induced hypertension by a mechanism which may, in part, be attributed to increased activity of MMP-9.

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Section: Discussionmentioning

confidence: 99%

Angiotensin-II induced hypertension and renovascular remodelling in tissue inhibitor of metalloproteinase 2 knockout mice

Pushpakumar

Kundu

Pryor

et al. 2013

Journal of Hypertension

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“…Therefore, the ratio of tumor blood flow to surrounding normal tissue blood flow increased. Tvete et al [19] reported less of a flow reduction in tumors (16%) than that in intact renal tissue (41%) after angiotensin II infusion.…”

Section: Discussionmentioning

confidence: 99%

Modification of tumor blood flow and enhancement of therapeutic effect of ACNU on experimental rat gliomas with angiotensin II

Tokuda¹,

Abe

Aida

et al. 1990

J Neuro-Oncol

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Blood flow was measured in transplanted rat gliomas before and during a constant intravenous infusion of angiotensin II using hydrogen clearance methods. The brain tumor models were produced in syngeneic Wister-King-Aptekman male rats with stereotaxic inoculation of ethylnitrosourea-induced glioma cells (KEG-1). Induced hypertension up to 150 mmHg (mean arterial pressure) with the infusion of angiotensin II resulted in a significant increase of blood flow to tumor center compared to the normotensive state (p less than 0.001). Blood flow measured simultaneously in brain tissue of tumor-free contralateral hemisphere did not change. The therapeutic effect of administration of the simultaneous 1-(4-Amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) and angiotensin II was evaluated in four experimental groups with the tumor-bearing rats. Twelve days after tumor implantation, the rats were administered angiotensin II to increase the mean arterial blood pressure to 150 mmHg, followed by intravenous injection of ACNU injection. The increased blood pressure was steadily maintained for 20 minutes. The ACNU/induced hypertension group showed a median survival time of 27.0 days, which was significant longer (p less than 0.02) than that of an ACNU treatment group (22.0 days), a hypertension treatment group (19.0 days), or a no treatment group (18.5 days). The enhanced therapeutic effect can be attributed to improving chemotherapeutic drug delivery due to increased blood flow in the tumor.

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“…(2), and as previously used in the present sarcoma model by TVETE et COIL (17,18). Briefly, platinum electrodes were made from 0.1 mm insulated platinum wire (Johnson Matthews Metals, England) with an exposed tip diameter of 0.1 mm and length 0.5 to 1 mm.…”

Section: Methodsmentioning

confidence: 99%

Effect of Reduced Perfusion Pressure and Acetylcholine on Local Blood Flow in Tumors in the Rat Kidney

Gadeholt

Hope

Tvete

et al. 1985

Acta Radiologica: Oncology

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Effect of Exogenous Angiotensin-II on Local Blood Flow in Kidneys with Neoplasm: Experiments in the rat

Cited by 9 publications

References 6 publications

Angiotensin-II induced hypertension and renovascular remodelling in tissue inhibitor of metalloproteinase 2 knockout mice

Angiotensin-II induced hypertension and renovascular remodelling in tissue inhibitor of metalloproteinase 2 knockout mice

Modification of tumor blood flow and enhancement of therapeutic effect of ACNU on experimental rat gliomas with angiotensin II

Effect of Reduced Perfusion Pressure and Acetylcholine on Local Blood Flow in Tumors in the Rat Kidney

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