Vascular Endothelial Growth Factor and Type 2 Receptor for This Factor in Vascular Malformations

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.

Cellular heterogeneity and immune microenvironment revealed by single-cell transcriptome in venous malformation and cavernous venous malformation

Venous malformation (VM) and cavernous venous malformation (CVM) are two types of vascular malformations. Even if the two diseases are similar in appearance and imaging, the distinct cellular components and signaling pathways between them might help distinguish the two from a molecular perspective. Here, we performed single-cell profiling of 35,245 cells from two VM samples and three CVM samples, with a focus on endothelial cells (ECs), smooth muscle cells (SMCs) and immune microenvironment (IME). Clustering analysis based on differential gene expression unveiled 11 specific cell types, and determined CVM had more SMCs. Re-clustering of ECs and SMCs indicated CVM was dominated by arterial components, while VM is dominated by venous components. Gene set variation analysis suggested the activation of inflammation-related pathways in VM ECs, and upregulation of myogenesis pathway in CVM SMCs. In IME analysis, immune cells were identified to accounted for nearly 30% of the total cell number, including macrophages, monocytes, NK cells, T cells and B cells. Notably, more macrophages and monocytes were discovered in VM, indicating innate immune responses might be more closely related to VM pathogenesis. In addition, angiogenesis pathway was highlighted among the significant pathways of macrophages & monocytes between CVM and VM. In VM, VEGFA was highly expressed in macrophages & monocytes, while its receptors were all abundantly present in ECs. The close interaction of VEGFA on macrophages with its receptors on ECs was also predicted by CellPhoneDB analysis. Our results document cellular composition, significant pathways, and critical IME in CVM and VM development.

Morphological Characteristic of Melanoma B16 Progression in C57BL/6 Mice with High and Low Resistance to Hypoxia

The features of B16 melanoma progression in male C57BL/6 mice with initially high and low resistance to hypoxia were studied. To assess the resistance to hypoxia, the mice were placed in a low-pressure chamber at a simulated altitude of 10,000 m. One month after testing, B16 melanoma was inoculated to high- and low-resistant animals. In 19 days after melanoma transplantation, the severity of melanoma progression was assessed by morphological and immunofluorescent methods. The expression of vegf-a and hif-1a in the liver of melanomabearing and control mice was evaluated by real-time PCR. Tumor growth progression was more pronounced in low-resistant mice, which was seen from high weight of the primary tumor node, relative necrosis area, proliferation rates (mitotic index and number of Ki-67+ cells), and expression of vegf-a gene in the liver. In high-resistant to hypoxia animals, the number of caspase-3+ cells dying by apoptosis was higher. The data on more rapid melanoma progression in mice with low resistance to hypoxia should be considered during the search of new prognostic markers and methods for therapy of malignant neoplasms.