Vascular endothelial growth factor blockade: A potential new therapy in the management of cerebral arteriovenous malformations

MicroRNA-135b-5p Is a Pathologic Biomarker in the Endothelial Cells of Arteriovenous Malformations

Arteriovenous malformations (AVMs) are congenital vascular anomalies with a poor prognosis. AVMs are considered intractable diseases, as there is no established approach for early diagnosis and treatment. Therefore, this study aimed to provide new evidence by analyzing microRNAs (miRNAs) associated with AVM. We present fundamental evidence for the early diagnosis and treatment of AVM by analyzing miRNAs in the endothelial cells of AVMs. This study performed sequencing and validation of miRNAs in endothelial cells from normal and AVM tissues. Five upregulated and two downregulated miRNAs were subsequently analyzed under hypoxia and vascular endothelial growth factor (VEGF) treatment by one-way analysis of variance (ANOVA). Under hypoxic conditions, miR-135b-5p was significantly upregulated in the AVM compared to that under normal conditions, corresponding to increased endothelial activity (p-value = 0.0238). VEGF treatment showed no significant increase in miR-135b-5p under normal conditions, however, a surge in AVM was observed. Under both hypoxia and VEGF treatment, comparison indicated a downregulation of miR-135b-5p in AVM. Therefore, miR-135b-5p was assumed to affect the pathophysiological process of AVM and might play a vital role as a potential biomarker of AVMs for application related to diagnosis and treatment.

New approaches for brain arteriovenous malformations-related epilepsy

BACKGROUND

The purpose of this review is to present the current literature and to highlight the most recent findings in brain arteriovenous malformations (bAVM)-related epilepsy research.

METHODS

We searched Medline, PubMed, Biblioinserm, Cochrane Central to study the latest research reports about the different factors that could be responsible for the genesis of bAVM-related epilepsy. We analyzed if epileptogenesis has any characteristics traits and its relation with the vascular malformation. The results of different treatments on epilepsy were considered. Typical errors that may lead towards incorrect or worse management of the seizures for these patients were also examined.

RESULTS

The development of bAVM results from multifactorial etiologies and bAVM-related epileptogenesis is likely specific for this pathology. Different types of evidence demonstrate a bidirectional relationship between bAVM and epilepsy. Currently, there is not enough published data to determine what may be the right management for these patients.

CONCLUSIONS

A better understanding of epileptogenesis in conjunction with knowledge of the complex alterations of structures and functions following bAVM-related seizures is necessary. Identification of biomarkers that can identify subgroups most likely to benefit from a specific intervention are needed to help guide clinical management. A new concept for the treatment of epilepsy related to an unruptured bAVM that cannot be treated invasively is proposed as well as new therapeutic perspectives. The next necessary step will be to propose additional algorithms to improve the development of future trials.

Study of the changed level of angiogenesis activation factors after endovascular treatment of arteriovenous malformations depending on the type of embolizing material and the radicality of exclusion of the malformation from the blood flow

Objective ‒ тo study changes in angiogenesis factors (VEGF-A, VEGFR-1, Great Endothelin-1) in the blood plasma of patients with arteriovenous malformation (AVM) of different localization before and after endovascular treatment depending on the type of embolizing material used and the results of AVM exclusion from the bloodstream.Materials and methods. The results of treatment in 2019–2022 were analyzed in 27 patients (11 (41.0 %) men and 16 (59.0 %) women) with AVMs of different localization who underwent endovascular treatment. The age of the patients ranged from 11 to 47 years, the average age was (32.8 ± 5.1) years. Patients with AVM were divided into two groups depending on the type of embolizing material: liquid substances (n=12) and emboli and coils (n=15). The control group was formed from 25 healthy people (10 men and 15 women) without AVM, in which the concentration of VEGF-A, VEGFR-1, Great Endothelin-1 in the blood plasma was determined for 3 months. The average age of the control group was (37.4 ± 4.8) years (from 16 to 57 years).Results. It was proved that the concentration of VEGF-A in blood plasma in patients with AVM before endovascular treatment was statistically significantly higher by 4.5 times than in the control group, VEGFR-1 by 3.0 times, Great Endothelin-1 by 2.12 times. Within 5‒7 days after embolization, a sharp increase in the level of angiogenesis induction factors was noted by 2.5–3.0 times compared to the initial indicator and a slow decrease during 3 months. However, with the use of liquid embolizing substances, no increase in VEGFR-1 concentration was registered. A comparison of the level of angiogenesis factors before and after endovascular surgical interventions revealed that the total exclusion of AVMs from the bloodstream contributes to the reduction or normalization of the content of angiogenesis factors, while the partial exclusion of AVMs from the bloodstream leads to an increase in their level due to the preservation of the source of production in the AVM structure.Conclusions. It was established that AVMs remain physiologically active during the life of the organism and undergo vascular remodeling as a result of constant pathological neoangiogenesis. Factors of angiogenesis actively respond to endovascular interventions by changing the expression of VEGF-A, VEGFR-1 and Great Endothelin-1 in the blood plasma, depending on the type of embolizing material and the radicality of AVM exclusion from the bloodstream. This is one of the main reasons for remission or further growth of AVMs and recurrences.

A human model of arteriovenous malformation (AVM)-on-a-chip reproduces key disease hallmarks and enables drug testing in perfused human vessel networks

Brain arteriovenous malformations (AVMs) are a disorder wherein abnormal, enlarged blood vessels connect arteries directly to veins, without an intervening capillary bed. AVMs are one of the leading causes of hemorrhagic stroke in children and young adults. Most human sporadic brain AVMs are associated with genetic activating mutations in the KRAS gene. Our goal was to develop an in vitro model that would allow for simultaneous morphological and functional phenotypic data capture in real time during AVM disease progression. By generating human endothelial cells harboring a clinically relevant mutation found in most human patients (activating mutations within the small GTPase KRAS) and seeding them in a dynamic microfluidic cell culture system that enables vessel formation and perfusion, we demonstrate that vessels formed by KRAS4A^G12V mutant endothelial cells (ECs) were significantly wider and more leaky than vascular beds formed by wild-type ECs, recapitulating key structural and functional hallmarks of human AVM pathogenesis. Immunofluorescence staining revealed a breakdown of adherens junctions in mutant KRAS vessels, leading to increased vascular permeability, a hallmark of hemorrhagic stroke. Finally, pharmacological blockade of MEK kinase activity, but not PI3K inhibition, improved endothelial barrier function (decreased permeability) without affecting vessel diameter. Collectively, our studies describe the creation of human KRAS-dependent AVM-like vessels in vitro in a self-assembling microvessel platform that is amenable to phenotypic observation and drug delivery.

Ten-year single-centre experience with type II endoleaks: Intervention versus observation

Our objective was to determine the relative merits of intervention or observation of type II endoleaks (T2Ls). A retrospective analysis was performed on 386 infra-renal endovascular aneurysm repair (IR-EVAR) patients from 2006 to 2015. Annual surveillance imaging of patients undergoing EVAR at our centre were analysed, and all endoleaks were subjected to a multidisciplinary team meeting for consideration and treatment. In the 10-year time frame, 386 patients (79.5±8.7 years) underwent an IR-EVAR. Eighty-one patients (21.0%) developed a T2L and intervention was undertaken in 28 (34.6%): 17 (60.7%) were treated via a transarterial approach (TA) and 11 (39.3%) using the translumbar approach (TL). Fifty-three patients (65.4%) with T2Ls were managed conservatively. Patients who received T2L treatment had a greater proportion of recurrent T2Ls than patients who were conservatively managed ( p=0.032). T2Ls associated with aneurysmal growth were more resistant to treatment than those where there was no change or a decrease in aneurysm size during follow-up (0.033). There was no significant difference in the TA and TL approach with respect to endoleak repair success ( p=0.525). Treatment of a T2L did not confer a survival advantage compared to conservative management ( p=0.449) nor did the choice of either the TA or TL approach ( p=0.148). Our study suggests the development of a T2L associated with aneurysm growth may represent an aggressive phenotype that is resistant to treatment. However, this did not lead to an increased risk of mortality over follow-up. Neither a transarterial nor a translumbar approach to treating a T2L conferred superiority.