fluorescence-angiography-for-evaluation-aneurysm-perfusion-parent

Fluorescence Angiography for Evaluation of Aneurysm Perfusion and Parent Artery Patency in Rat and Rabbit Aneurysm Models

Brain aneurysm treatment focuses on achieving complete occlusion, as well as preserving blood flow in the parent artery. Fluorescein sodium and ...

arterial-pouch-microsurgical-bifurcation-aneurysm-model-in-the-rabbit

Arterial Pouch Microsurgical Bifurcation Aneurysm Model in the Rabbit

Endovascular treatment for intracranial aneurysms gained importance over the past decades, consequently there is an increased need of testing endovascular ...

using-cell-tracer-injection-to-investigate-origin-neointima-forming

Using a Cell-Tracer Injection to Investigate the Origin of Neointima-Forming Cells in a Rat Saccular Side Wall Model

Microsurgical clipping creates a subsequent barrier of blood flow into intracranial aneurysms, whereas endovascular treatment relies on neointima and ...

University of Bern

The inflammatory pathway in cerebrospinal fluid (CSF) leads to delayed cerebral vasospasm (DCVS) and delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH). The role of IL-1α has never been evaluated in a rabbit SAH model. The aim of our study is to analyze systemic and CSF changes of IL-1α, and to evaluate potential associations with the onset of DCVS in a rabbit closed cranium SAH model. Methods 17 New Zealand white rabbits were randomized into two groups, SAH ( = 12) and sham ( = 5). In the first group, SAH was induced by extracranial-intracranial shunting from the subclavian artery into the cerebral cistern of magna under intracranial pressure (ICP) monitoring. The sham group served as a control. The CSF and blood samples for IL-1α measurement were taken at day zero before SAH induction and at day three.

Systemic and CSF Interleukin-1α Expression in a Rabbit Closed Cranium Subarachnoid Hemorrhage Model: An Exploratory Study.

: Delayed cerebral vasospasm (DCVS) due to aneurysmal subarachnoid hemorrhage (aSAH) and its sequela, delayed cerebral ischemia (DCI), are associated with poor functional outcome. Endothelin-1 (ET-1) is known to play a major role in mediating cerebral vasoconstriction. Angiotensin-II-type-1-receptor antagonists such as Sartans may have a beneficial effect after aSAH by reducing DCVS due to crosstalk with the endothelin system. In this review, we discuss the role of Sartans in the treatment of stroke and their potential impact in aSAH. : We conducted a literature research of the MEDLINE PubMed database in accordance with PRISMA criteria on articles published between 1980 to 2019 reviewing: "Sartans AND ischemic stroke". Of 227 studies, 64 preclinical and 19 clinical trials fulfilled the eligibility criteria. : There was a positive effect of Sartans on ischemic stroke in both preclinical and clinical settings (attenuating ischemic brain damage, reducing cerebral inflammation and infarct size, increasing cerebral blood flow). In addition, Sartans reduced DCVS after aSAH in animal models by diminishing the effect of ET-1 mediated vasoconstriction (including cerebral inflammation and cerebral epileptogenic activity reduction, cerebral blood flow autoregulation restoration as well as pressure-dependent cerebral vasoconstriction). : Thus, Sartans might play a key role in the treatment of patients with aSAH.

The Role of Sartans in the Treatment of Stroke and Subarachnoid Hemorrhage: A Narrative Review of Preclinical and Clinical Studies.

 Biological processes that lead to aneurysm formation, growth and rupture are insufficiently understood. Vessel wall inflammation and degeneration are suggested to be the driving factors. In this study, we aimed to investigate the natural course of vital (non-decellularized) and decellularized aneurysms in a rabbit sidewall and bifurcation model.  Arterial pouches were sutured end-to-side on the carotid artery of New Zealand White rabbits (vital [ = 6] or decellularized [ = 6]), and into an end-to-side common carotid artery bifurcation (vital [ = 6] and decellularized [ = 6]). Patency was confirmed by fluorescence angiography. After 28 days, all animals underwent magnetic resonance and fluorescence angiography followed by aneurysm harvesting for macroscopic and histological evaluation.  None of the aneurysms ruptured during follow-up. All sidewall aneurysms thrombosed with histological inferior thrombus organization observed in decellularized compared to vital aneurysms. In the bifurcation model, half of all decellularized aneurysms thrombosed whereas the non-decellularized aneurysms remained patent with relevant increase in size compared to baseline.  Poor thrombus organization in decellularized sidewall aneurysms confirmed the important role of mural cells in aneurysm healing after thrombus formation. Several factors such as restriction by neck tissue, small dimensions and hemodynamics may have prevented aneurysm growth despite pronounced inflammation in decellularized aneurysms. In the bifurcation model, rarefication of mural cells did not increase the risk of aneurysm growth but tendency to spontaneous thrombosis.

Comparison of Aneurysm Patency and Mural Inflammation in an Arterial Rabbit Sidewall and Bifurcation Aneurysm Model under Consideration of Different Wall Conditions.

Early brain injury (EBI), delayed cerebral vasospasm (DCVS), and delayed cerebral ischemia (DCI) are common complications of subarachnoid hemorrhage (SAH). Inflammatory processes in the cerebrospinal fluid (CSF) are one of the causes for such complications. Our aim to study the effects of an IL-6 receptor antagonist (Tocilizumab) examines the occurrence of DCVS, neuronal cell death, and microclot formation in an acute SAH rabbit model. Twenty-nine New Zealand white rabbits were randomized into one of three groups as the SAH, SAH + Tocilizumab, and sham groups. In SAH groups, hemorrhage was induced by extracranial-intracranial arterial blood shunting from the subclavian artery into the cisterna magna under intracranial pressure (ICP) monitoring. In the second group, Tocilizumab was given once intravenously 1 h after SAH induction. Digital subtraction angiography was performed, and CSF and blood were sampled before and after (day 3) SAH induction. IL-6 plasma and CSF levels were measured. TUNEL, FJB, NeuN, and caspase-3 immunostaining were used to assess cell apoptosis, neurodegeneration, and neuronal cell death, respectively. Microclot formation was detected by fibrinogen immunostaining. Between baseline and follow-up, there was a significant reduction of angiographic DCVS (p < 0.0001) in the Tocilizumab compared with the SAH group. Tocilizumab treatment resulted in decreased neuronal cell death in the hippocampus (p = 0.006), basal cortex (p = 0.001), and decreased microclot formation (p = 0.02). Tocilizumab reduced DCVS, neuronal cell death, and microclot formation in a rabbit SAH model, and could be a potential treatment to prevent DCVS and DCI in SAH patients.

Tocilizumab Reduces Vasospasms, Neuronal Cell Death, and Microclot Formation in a Rabbit Model of Subarachnoid Hemorrhage.

Aneurysm wall degeneration is linked to growth and rupture. To address the effect of aspirin (ASA) on aneurysm formation under various wall conditions, this issue was analyzed in a novel rabbit bifurcation model.

Aspirin treatment prevents inflammation in experimental bifurcation aneurysms in New Zealand White rabbits.

Delayed cerebral vasospasm (DCVS), early brain injury (EBI), and delayed cerebral ischemia (DCI) are devastating complications after aneurysmal subarachnoid hemorrhage (SAH). Interleukin (IL)-6 seems to be an important interleukin in the inflammatory response after SAH, and many studies describe a strong correlation between IL-6 and worse outcome. The aim of this study was to systematically review preclinical and clinical studies that evaluated systemic and cerebral IL-6 levels after SAH and their relation to DCVS, neuronal cell death, and DCI. We conducted two systematic literature searches using PubMed to identify preclinical and clinical studies evaluating the role of IL-6 after SAH. Suitable articles were selected based on predefined eligibility criteria following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A total of 61 and 30 preclinical and clinical articles, respectively, were included in the systematic reviews. Of the preclinical studies in which IL-6 was measured in cerebrospinal fluid (CSF), parenchyma, and systemically, 100%, 94.4%, and 81.3%, respectively, showed increased expression of IL-6 after SAH. Preclinical results were mirrored by clinical findings in which elevated levels of IL-6 in CSF and plasma were found after SAH, correlating with DCVS, DCI, and worse outcome. Only two preclinical studies analyzed the direct inhibition of IL-6, which resulted in reduced DCVS and neuronal cell death. IL-6 is a marker of intracranial inflammation and plays a role in the pathophysiology of DCVS and DCI after SAH in preclinical animal models and clinical studies. Its inhibition might have therapeutic potential to improve the outcome of SAH patients.

Preclinical and clinical role of interleukin-6 in the development of delayed cerebral vasospasm and neuronal cell death after subarachnoid hemorrhage: towards a potential target therapy?

Unlike clipping that forms an immediate barrier of blood flow into intracranial aneurysms, endovascular treatments rely on thrombus organization and neointima formation. Therefore, a continuous endothelial cell layer is crucial to prevent blood flow in the former aneurysm. This study investigates the origin of endothelial cells in the neointima of endovascular treated aneurysms, specifically whether cells from the parent artery play a role in neointima formation.

ArticleTotal : 3	Year
Publication title Cited by 5	2019
Publication title Cited by 11	2020
Publication title Cited by 2	2022

Article	Year
Systemic and CSF Interleukin-1α Expression in a Rabbit Closed Cranium Subarachnoid Hemorrhage Model: An Exploratory Study. Brain sciences\| PubMed ID: 31554320	2019
The Role of Sartans in the Treatment of Stroke and Subarachnoid Hemorrhage: A Narrative Review of Preclinical and Clinical Studies. Brain sciences\| PubMed ID: 32156050	2020
Comparison of Aneurysm Patency and Mural Inflammation in an Arterial Rabbit Sidewall and Bifurcation Aneurysm Model under Consideration of Different Wall Conditions. Brain sciences\| PubMed ID: 32230757	2020
Tocilizumab Reduces Vasospasms, Neuronal Cell Death, and Microclot Formation in a Rabbit Model of Subarachnoid Hemorrhage. Translational stroke research\| PubMed ID: 33409731	2021
Aspirin treatment prevents inflammation in experimental bifurcation aneurysms in New Zealand White rabbits. Journal of neurointerventional surgery\| PubMed ID: 33785639	2021
Preclinical and clinical role of interleukin-6 in the development of delayed cerebral vasospasm and neuronal cell death after subarachnoid hemorrhage: towards a potential target therapy? Neurosurgical review\| PubMed ID: 34448990	2022
Parent artery-initiated and stent-mediated neointima formation in a rat saccular side wall model. Journal of neurointerventional surgery\| PubMed ID: 35110397	2022

Sivani Sivanrupan

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