Vascular Research Articles

Abstract 4115642: Resonance Sonomanometry in an Early Prototype Device Effectively Measures Continuous, Noninvasive Blood Pressure

Background: Nearly half of American adults have hypertension; however, reliable, continuous, noninvasive blood pressure (BP) measurement (cNIBP) for inpatient and outpatient use is not currently available. This study evaluated a new method for cNIBP measurement called resonance sonomanometry (RSM). RSM derives blood pressure using first-principles physics, is applicable to any artery, and requires no calibration, blood vessel deformation, or dependence on demographic inputs. Methods: A prospective, observational feasibility study was undertaken to compare carotid artery BP measurements with a prototype ultrasound-based cNIBP device incorporating RSM, to arterial catheter BP measurements in the radial arteries of 60 test subjects. Catheter measurements were obtained from a distal peripheral artery (radial), oscillometric cuff from the brachial artery, and RSM was obtained from a central artery (carotid). This study was the first-in-human study for the RSM method in comparison to arterial catheters. Results: RSM-induced arterial resonance was observed in all tested subjects. For each of the subjects, the arterial resonant frequency increased with increasing BP during systole, and decreased with diastole (consistent with the cardiac cycle), as predicted by the physical model. RSM-derived BP traces were qualitatively similar to catheter data, exhibiting features such as the dicrotic notch. The RSM method yielded similar diastolic BP (DBP), but lower systolic BP (SBP) compared to the arterial catheter, likely due to expected peripheral pulse amplification. RSM DBP was not significantly different from the catheter (+1.5mmHg, p = 0.187), while BP cuff DBP was significantly different from the catheter (−4.3mmHg, p=0.002). There were significant differences in the catheter to RSM SBP (34.1 mmHg, p < 0.01), consistent with the aforementioned expectations from a central-versus-peripheral continuous pressure measurement. Conclusions: RSM is a novel BP measurement technique that could enable cNIBP measurements with accuracy required in hospitals. While the data are promising, significant future work remains. The study was meant to test the RSM method, not the device or form factor. Consequently, the form factor will need to be improved prior to clinical use. The prototype was designed for manual operation; thus, future work will also be needed to enhance the ability of the device to autonomously locate and track the artery for ease of use.

Integrated surgical intervention for intradural extramedullary hemangioblastoma of the cervical spine: a case report and literature review

IntroductionThe incidence of hemangioblastoma is low, constituting only 1-5% of all spinal cord tumors. Specifically, intradural extramedullary hemangioblastoma without Von Hippel-Lindau syndrome represents an exceedingly rare condition.MethodsWe report the first documented case of cervical intradural extramedullary hemangioblastoma in China. A 53-year-old male patient presented with a 3-year history of mild right hemiplegia, segmental muscle strength and sensation impairment, and a positive pyramidal tract sign. MRI showed an abnormal oval signal focus in the intradural and extramedullary region at the C6-C7 vertebral level. Before surgery, angiography was performed to identify the supplying arteries and draining veins. Subsequent interventional therapy achieved over 90% occlusion of blood vessels, creating optimal conditions for complete resection of the spinal tumor.ResultsThe patient demonstrated satisfactory postoperative recovery with significant restoration of sensory and motor functions. Pathological examination showed a significant upregulation of CD31 in tumor cells and a substantial presence of the neuro-specific marker S100 in the tumor stroma, consistent with the diagnostic criteria for spinal hemangioblastoma.ConclusionThe rarity of cervical intradural extramedullary hemangioblastoma without Von Hippel-Lindau syndrome was reaffirmed by a comprehensive review of the existing literature. Complete tumor resection remains the optimal approach for managing this uncommon condition, generally resulting in a favorable prognosis. Traditional open fenestration surgery is linked to elevated risks of bleeding and trauma. Meanwhile, endovascular injection of embolic agents may lead to residual lesions and an increased risk of recurrence. Therefore, we recommend a one-time combined treatment conducted in a hybrid operating room to achieve complete resection and effectively reduce intraoperative bleeding risk. Despite presenting challenges and requiring high proficiency, we still recommend this type of combined surgery as a suitable therapeutic option for such diseases.

Abstract 4124084: Nitric Oxide Releasing Bionanomatrix Gel For Dialysis Arteriovenous Fistula Maturation

Introduction: About 600,000 patients in the US suffer from end-stage renal disease (ESRD); more than 75% of ESRD patients undergo dialysis. Vascular access dysfunction is a major cause of morbidity and hospitalization in dialysis patients. Arteriovenous fistulas (AVFs) are considered the gold standard of vascular access for dialysis. However, about 60% of AVFs fail to mature because of early venous neointimal development and poor vasodilation and vascular wall remodeling. Therefore, to promote AVF maturation, we propose the application of a nitric oxide (NO) releasing nanomatrix gel, or ‘NO gel’, on the created AVF. The NO gel is composed of peptide amphiphiles (PA), which contain a polylysine (KKKKK) group to form NO-donating residues. In this study, we test our hypothesis that the NO gel applied at AVF can promote AVF maturation by decreasing venous intimal hyperplasia, enhancing vasodilation and vascular outward remodeling in porcine model. Materials and Methods: PA containing with KKKKK was synthesized and charged with NO to produce NO gel. For in vivo studies, AVFs in porcine were created by connecting the jugular vein and carotid artery. The NO gel was applied perivascularly over the AVF anastomosis. And the pigs were sacrifice after 35 days. AVF hemodynamics were evaluated using MRI-based computed fluid dynamics analysis. Results: We found significant decrease in neointimal hyperplasia in porcine AVFs treated with NO gel compared to the control groups. Additionally, the percentage of open lumens was significantly higher in the NO gel-treated group. It is indicated that veins in NO treated group showed less fibrosis as an less type I collagen I produced in the NO treated group than control. Also, the NO gel significantly improved hemodynamics and vascular remodeling of porcine AVFs compared to the control. Conclusion: These results suggest that the NO gel plays a crucial role in AVF maturation by reducing intimal hyperplasia and stenosis following AVF creation in a pig model. When intimal hyperplasia is reduced and the vessel is dilated, less tensile force of blood flow is applied on the arterialized vein, directing the AVF to appropriate maturation.

Large depth-of-field ultraviolet-visible photoacoustic histologic and microvascular imaging in vivo

Photoacoustic microscopy (PAM) can image diverse biological microstructures by harnessing characteristic optical absorption spectra of intrinsic nonfluorescent biomolecules. We incorporate ultraviolet (UV) and visible pulsed lasers into a PAM to develop an UV-visible PAM for label-free histologic and microvascular imaging, where the cell nuclei and blood vessels are specifically captured at high contrast relying on strong optical absorption of DNA/RNA and hemoglobin at 266 and 532 nm wavelengths, respectively. Moreover, two diffractive optical elements operating at UV and visible spectra are designed for engineering the excitation beams, significantly enlarging depths of field (DOFs > 200 μm). The UV-visible PAM demonstrates combined capabilities of dual imaging contrast, elongated DOFs, and micrometer-scale lateral resolution for delineating the spatial microarchitectures of both cell nuclei and blood vessels that are at different depth locations in the biological specimens with uneven surfaces. Longitudinal monitoring of the trauma is performed in mouse ear in vivo. Potentially, our UV-visible PAM could offer comprehensive histologic and microvascular information in a broad range of biomedical studies.

ANGI-03. GLIOMA STEM CELLS INDUCE VASECTASIA – A NON-ANGIOGENIC BRAIN TUMOUR NEOVASCULARIZATION PROCESS DRIVEN BY INTERCELLULAR EGFR TRANSFER THROUGH EXTRACELLULAR VESICLES

Abstract Tumour neovascularization in glioblastoma (GBM) is abundant, abnormal and poorly understood, and it likely involves multiple co-existing mechnanisms with distinct modes of regulation. Since glioma stem cells (GSCs) engage in bidirectional interactions with the vasculature we dissected the resulting vascular responses elicited by either proneural (PN), or mesenchymal (MES) GSC subtypes established from patients isolates and able to drive progression of orthotopic intracranial xenografts in mice. We report here that while PN-GSCs elicited mostly angiogenesis-type vascular capillary growth processes, their MES-GSC counterparts elicited non-angiogenic growth of enlarged vessels (vasectesia), paradoxically associated with reduced blood vessel density. Vasectasia was dependent on the expression of oncogenic EGFR/EGFRvIII by MES-GSCs, and on the related kinase/signalling activity, as EGFR/EGFRvIII gene disruption and Dacomitinib treatment suppressed formation of large blood vessels in vivo and resulted in a preponderance of a small calliber (angiogenic) vasculature throughout xenografts. Notably, the analysis of spatial transcriptomes and single cell RNA sequencing revealed distinct molecular traits of endothelial cells asociated with vasectasia and angiogesis, the former enriched in Birc5, but depleted for angiogenic tip cell markers (Vegfr2, Apln). Mechnaistically, vasectasia was linked to the intercellular transfer of EGFR from MES-GSCs to endothelial cells resulting in ectopic activation of EGFR signalling in the endothelial cell bacground, both in vitro and in a model of in vivo blood vessel recruitment into implanted matrigel pellets. Simultaneous pharmacological blockade of both, angiogenesis (anti-VEGR2) and vasectasia (Dacomitinib) lead to a marked increase in survival of mice with aggressive GBM lesions initiated by MES-GSCs. We suggest that, vasectasia driven by intercellular transfer of oncogenic EGFR may represent a new, subtype-specific mechanism of GBM neovascularization, and a plausible target for agents aiming to modify vascular tumour microenvironment.

ETIOPATHOGENETIC MECHANISMS OF IMMUNE DYSFUNCTION IN COMBATANTS WITH LOWER LIMB SOFT TISSUE INJURIES UNDER CHRONIC STRESS

Introduction. Combat injuries, including gunshot, shrapnel, and mine-explosive wounds, affect a significant number of soldiers in modern warfare. Notably, most of these injuries involve damage to the soft tissues of the extremities. Surgeons have expressed concerns regarding the unsatisfactory treatment outcomes in this group of combatants, attributing one of the primary challenges to the limited understanding of immune dysfunction pathogenesis in military trauma cases. This study aims to address this gap by examining immune system dysfunctions in combat-related injuries. The objective of this study is to thoroughly analyze and synthesize the key stages of immune dysfunction occurring over extended periods post-combat trauma, including the subsequent development of traumatic disease and various wound complications. Materials and Methods. The rising prevalence of combat trauma among soldiers has intensified interest in studying this issue, prompting surgeons and traumatologists to address its various medical aspects comprehensively. The literature search focused on recent publications, allowing for a targeted analysis of the immunological aspects relevant to military medical traumatology. Results. In the initial stages of severe or combined injuries affecting various tissues—such as tubular bones, joints, blood vessels, and peripheral nerves—systemic inflammatory response syndrome (SIRS) commonly occurs. This stage is marked by an intense activation of innate antibacterial and immune-protective responses, leading to a significant increase in inflammation. This initial response is soon replaced by a prolonged phase known as compensatory anti-inflammatory response syndrome. During this period, immune-protective responses sharply decrease, certain immunocompetent cells become inhibited, and lymphopenia develops. This phase is often accompanied by infectious contamination of wounds with pathogenic and opportunistic microorganisms, resulting in both local purulent-necrotic processes and potentially severe systemic complications, such as septic shock, sepsis, multiple organ failure, and others. The final stage, known as persistent inflammatory, immunosuppressive, catabolic syndrome, is characterized by the chronic progression of traumatic disease, accompanied by ongoing immune system dysfunction in combatants. Conclusion. In the early period of traumatic injury, the wounded experience sharp inflammatory processes and activation of immune defense mechanisms. At subsequent stages, severe disruptions in the functioning of the immune system, damage to internal organs, and the development of catabolic syndrome are recorded. These changes, especially those resulted from exposure to chronic combat stress preceding the injury, aggravate the processes of infectious decontamination of wounds, regeneration of damaged tissues, and the general process of combatant rehabilitation.

EPCO-18. DECIPHERING SPATIAL DIVERSITY OF GLIOBLASTOMA GENETIC ARCHITECTURE

Abstract Glioblastoma (GBM) is hallmarked by profound inter- and intratumoral heterogeneity. Current research has mapped key genetic drivers to distinct transcriptional profiles within GBM. Nevertheless, the intricate interactions between genetic alterations and spatial-transcriptional heterogeneity remain elusive. We utilized nestin-Tva C57BL/6 mice to induce de novo GBM via oncogene overexpression alongside shRNA-mediated silencing or deletion of tumor suppressors. We modeled critical driver mutations: PDGFB, NF1, and EGFR. Employing 10X Genomics platform for single-cell RNA sequencing, combined with spatially resolved transcriptomics and proteomics (Nanostring GeoMx), we integrated data using both horizontal (mutual nearest neighbors) and vertical (weighted nearest neighbors) approaches, analyzed through the SPATA2 software. Advanced computational techniques, including graph neural networks and single-cell deconvolution, were leveraged to unravel the genotypic and spatial variability within tumors and their microenvironments. Our findings uncover persistent cellular heterogeneity across diverse genetic contexts. However, specific genetic mutations precipitated distinct dominant transcriptional states: NF1 and EGFR mutations drove mesenchymal and astrocytic-like states, respectively, whereas PDGFB fostered a neural progenitor/cell-like state. These transcriptional shifts were closely linked to unique microenvironmental modifications, such as elevated neuronal signaling in PDGFB-driven GBMs and significant immune infiltration in NF1 and EGFR models. Through weighted co-expression network analysis (WGCNA) and gene set enrichment analysis (GSEA) paired with spatial-niche deconvolution, we identified a mesenchymal transition leading to an immunosuppressive microenvironment in NF1-loss driven GBMs and increased lymphocyte presence around blood vessels in EGFR-amplified GBMs. These patterns were consistent with human spatially resolved transcriptomic data, emphasizing the genetic complexity and heterogeneity of human GBMs. Our genetically engineered mouse models serve as a robust platform for dissecting GBM with defined genetic mutations. Leveraging sophisticated analytical techniques and computational modeling, this study underscores the profound interplay between genetic drivers and the tumor microenvironment, paving the way for targeted therapeutic strategies and precision medicine in GBM.

SFNet: Spatial and Frequency Domain Networks for Wide-Field OCT Angiography Retinal Vessel Segmentation.

Automatic segmentation of blood vessels in fundus images is important to assist ophthalmologists in diagnosis. However, automatic segmentation for Optical Coherence Tomography Angiography (OCTA) blood vessels has not been fully investigated due to various difficulties, such as vessel complexity. In addition, there are only a few publicly available OCTA image data sets for training and validating segmentation algorithms. To address these issues, we constructed a wild-field retinal OCTA segmentation data set, the Retinal Vessels Images in OCTA (REVIO) dataset. Second, we propose a new retinal vessel segmentation network based on spatial and frequency domain networks (SFNet). The proposed model are tested on three benchmark data sets including REVIO, ROSE and OCTA-500. The experimental results show superior performance on segmentation tasks compared to the representative methods.

THE IMPACT OF EXOGENOUS AND ENDOGENOUS FACTORS ON VASCULAR WALL ELASTICITY AND POTENTIAL CLINICAL EFFECTS (Review Article)

Vascular aging is associated with profound changes in the structural properties of the arterial wall. Arterial hypertension, diabetes mellitus, and chronic kidney disease are the primary determinants of the loss of elasticity and reduced compliance of the vascular wall. Arterial stiffness is a key parameter for assessing the elasticity of the arterial wall and can be easily evaluated using non-invasive methods such as pulse wave velocity. Early assessment of arterial stiffness is critical, as its changes may precede the clinical manifestations of cardiovascular disease. With age, arterial walls become stiffer, leading to an increase in systolic blood pressure and an increased risk of cardiovascular events such as stroke, myocardial infarction, or heart failure. The gradual decrease in vascular elasticity is accompanied by remodeling of their structure, an increase in collagen fibers, and a decrease in elastin, which exacerbates the problem. In addition, the mechanical stress on the vascular wall, which increases with age, worsens its condition, provoking the formation of atherosclerotic plaques. Arterial stiffness, as an important biomarker of vascular aging, is also an indicator of increased cardiovascular risk, independent of other factors such as blood pressure or the presence of comorbidities. Therefore, timely diagnosis of arterial stiffness can help prevent serious complications and adjust treatment for patients at risk. Important are also preventive measures, including a healthy lifestyle, physical activity, and control of the underlying diseases that contribute to the acceleration of vascular aging processes. Moreover, the influence of endogenous and exogenous factors, such as diet, the presence of chronic diseases, and bad habits (in particular, smoking), contribute to the acceleration of these processes. Innovative diagnostic methods, such as magnetic resonance imaging (MRI) or ultrasound, allow detecting these changes at early stages and, accordingly, adapting treatment.

TMIC-38. INTEGRIN BLOCKING PEPTIDE REPROGRAMS THE IMMUNOSUPPRESSIVE MICROENVIRONMENT OF EXPERIMENTAL GLIOMAS IMPROVING ANTI-PD-1 THERAPY OUTCOME

Abstract Clinical trials with immune checkpoint inhibitors (ICI) have benefited many cancer patients but failed in a number of tumors, including glioblastoma (GBM), the most common and aggressive primary brain tumor in adults. The main obstacle for ICI efficacy in GBM is the continuously evolving tumor microenvironment (TME), in which antitumor immunity is inhibited or eluded by tumor-secreted factors. Accumulation and reprogramming of myeloid cells (GAMs) creates a “cold” immunosuppressive TME with a poor infiltration and exhaustion of effector T cells. We employ Cellular Indexing of Transcriptomes and Epitopes by sequencing (CITE-seq) with 40 protein markers along with spatial transcriptomics and immunophenotyping to dissect identities and functionalities of immune cells (CD45+) in experimental GL261 gliomas. The results revealed identities of immune cells instrumental for creating the immunosuppressive milieu and cell-cell communication networks. We have developed a designer RGD peptide that blocks the reprogramming of GAMs by targeting tumor-GAMs interactions. We demonstrate that RGD efficiently blocks microglia-dependent invasion of murine and human glioma cells in vitro. We explored if the intratumorally delivered RGD can revert tumor-induced changes in the TME of experimental gliomas and improve anti-PD-1 immunotherapy. While RGD alone did not reduce tumor growth in vivo, it prevented reprogramming of myeloid cells into protumoral GAMs and led to the normalization of peritumoral blood vessels. Combining RGD with anti-PD-1 antibody resulted in reduced tumor growth, increase in percentages of proliferating, interferon-ɣ producing CD8+T cells and depletion of regulatory T cells. Transcriptomic profiles of GAMs were altered by the combined treatment, consistently with the restored “hot” inflammatory TME which resulted in boosting immunotherapy responses. Intratumorally delivered RGD modified in the same way functionalities of GAMs in the TME of human U87MG gliomas in nude mice. Our results demonstrate that the integrin blockade combined with immune checkpoint inhibitors reinvigorates both innate and adaptive antitumor immunity. The results pave the way to improve responses to immunotherapy in GBM and other cancers.

TMOD-11. ADVANCED MRI ANALYSIS TO ASSESS CHEMO-RADIATION RESPONSE IN PEDIATRIC EPENDYMOMA MODELS

Abstract Pediatric Ependymoma (EPN) is an aggressive brain tumor for which the benefits of chemo-radiation (CR) therapy have yet to be established. Our team has previously reported behavior patterns of EPN, including high tumor cellularity, cytological anaplasia, high mitotic index, tumor necrosis, and the presence of inflammatory cells such as M2-type macrophages. Recently, we have established advanced MRI protocols and computational algorithms for cell- and vessel-size imaging. The goal of this study is to develop advanced MRI analysis for CR response biomarkers (including tumor size, cell- and vessel-size correlates, and texture analysis) in mice with patient-derived xenografts (PDX) of pediatric EPN. Female severely immune deficient (SCID) mice were used for intracranial orthotopical inoculation of disaggregated tumors from pediatric EPN patients. All multi-parametric MRI sequences (fast spin echo, FLAIR, diffusion weighted, quantitative T2- and r2*-maps) were acquired on a Bruker 9.4 Tesla MRI scanner prior to CR, followed by 2 days and 2 weeks after CR treatment. All radiation treatment was performed using an animal image-guided precision XRAD irradiator (2Gyx5days), using MRI and CT guided EPN localization with added 30 mg/kg 5-fluoracil. All MRI analysis was performed using Bruker ParaVision software and MATLAB based modeling. The sensitivity of T2w-MRI scans was 0.2 mm for the smallest tumor detected; the median tumor volume at baseline was 2.5 mm3. Untreated mice showed rapid progression of tumor growth from small to intermediate to large EPN. The increased tumor sizes in untreated EPN were characterized by low ADC, highly elevated blood vessel density and large tumor cell size. A significant decrease in vessel size density and an increase in inflammatory cells were seen as soon as 2 days after CR therapy. The late response (2 weeks post CR) is characterized by increased ADC values and decreased cell size, resulting in significantly decreased tumor volumes.

MicroRNAs, endometrial receptivity and molecular pathways.

MicroRNAs (miRNAs) are a type of specific molecules that control the activities of the uterus, such as the process of cellular maturing and evolution. A lot of substances like growth factors, cytokines, and transcription factors play a role in embryo-endometrial interaction. MiRNAs could regulate various these factors by attaching to the 3' UTR of their mRNAs. Moreover, current research show that miRNAs participate in formation of blood vessels in endometrium (miR-206, miR-17-5p, miR-16-5p…), decidualization (miR-154, miR-181, miR-9…), epithelial-mesenchymal transition (miR-30a-3p), immune response (miR-888, miR-376a, miR-300…) embryo attachment (miR-145, miR-27a,451…) and pinopod formation (mir-223-3p, mir-449a, mir-200c). In this study, the focus is on the role of miRNAs in managing the uterus' receptivity to an embryo and its ability to facilitate attachment. More specifically, we are exploring the mechanisms by which miRNAs regulate the presence of specific molecules involved in this crucial physiological process.

Clotting promotes glioma growth and infiltration through activation of focal adhesion kinase.

The tumor architecture of high-grade gliomas is shaped by tumor cell necrosis, invasive growth and the leakage of a fibrin-rich edema from poorly organized tumor blood vessels. Here, we demonstrate a marked upregulation of clot formation in the interstitial spaces of tumor tissues from patients with glioblastoma while tumor-free brain is essentially devoid of fibrin. The accumulation of fibrin in tumor interstitial spaces is functionally relevant as we demonstrate increased infiltration and growth of primary glioblastoma cells after embedding in a 3-dimensional matrix made of fibrin ex vivo. Additionally, we detected accelerated tumor growth after implanting glioblastoma cells together with clotted plasma in brains of immune deficient mice while glioblastoma development in clotting-deficient hemophilia mice was delayed. Glioblastoma growth correlated with the outgrowth of invadopodia and their adhesive interactions with the 3-dimensional clot matrix, which was mediated by integrins β1 and β3 and their common downstream target focal adhesion kinase (FAK). Knocking down FAK with CRISPR Cas9 caused an upregulation of p21/p27 cell cycle inhibitors, strong growth inhibition in cultured glioblastoma cells and sustained anti-tumorigenic effects in orthotopic glioblastoma xenografts in vivo. These results go hand in hand with genomic data from The Cancer Genome Atlas that indicate increased clotting activity and reduced patient survival in glioma subgroups with high integrin β1 and β3 expression. We therefore conclude that clotting in glioma interstitial spaces provides tumor cells with a potent proliferative stimulus that can be reversed by targeting the adhesive machinery of glioblastoma cells via inhibition of FAK.

3D printed sodium alginate/gelatin/tannic acid/calcium chloride scaffolds laden bone marrow mesenchymal stem cells to repair defective thyroid cartilage plate.

Due to the absence of blood vessels, cartilage exhibits extremely limited self-repair capacity. Currently, repairing laryngeal cartilage defects, resulting from conditions such as laryngeal tumors, injury, and congenital structural abnormalities, remains a significant challenge in the Department of Otolaryngology, Head and Neck Surgery. Previous research has often focused on enhancing the mechanical properties of synthetic materials. However, their low biological activity and weak cell adhesion necessitate compensatory measures. This study aims to capitalize on the advantages of natural materials in cartilage tissue engineering. Sodium alginate, gelatin, tannic acid, and calcium chloride were utilized to prepare bioinks through cross-linking for application in 3D printing cartilage scaffolds. Bone marrow mesenchymal stem cells with multidirectional differentiation potential were chosen as seed cells, with appropriate growth factors incorporated to promote their differentiation into cartilage during in vitro culture. The scaffold laden cells was subsequently implanted into rabbit thyroid cartilage plate defects at the appropriate time. HE staining, toluidine blue staining, Masson staining, and collagen type II staining were employed to assess cartilage defect repair at 4, 8, and 12 weeks, respectively. Results demonstrated that scaffolds made from natural materials could emulate the mechanical properties of fresh cartilage with commendable biocompatibility. Stained sections further confirmed the efficacy of the composite hydrogel scaffolds identified in this study in promoting rabbit thyroid cartilage plate restoration. In summary, this study successfully fabricated a natural material scaffold for rabbit laryngeal cartilage tissue engineering, thereby furnishing a new idea and experience for the clinical application of laryngeal cartilage defect reconstruction.

TMIC-64. EXPLORING ULTRASTRUCTURAL PATHOLOGY IN GLIOMAS: INSIGHTS FROM RECENT STUDIES

Abstract Glioma tumors arise from the glial cells making up to 40% of the brain tumors, and contributing up to 85% of the malignant tumors of the brain. Gliomas are a heterogeneous group of tumors classified based on various factors such as genetics, molecular profiles, etc. Glioblastoma, an aggressive form of gliomas, has incredibly low survival of only 15 months suggesting that thorough research, improved diagnostics, and therapeutics development is needed to improve the outcomes for patients with gliomas. These advancements require a critical analysis of the microenvironment of gliomas to understand the pathophysiology at play. Ultrastructural analysis (UA) using high-resolution electron microscopy offers crucial insights into the cellular and subcellular characteristics of gliomas, revealing organelle abnormalities and confirming molecular alterations. In this review, we focus on the recent developments exploring the ultrastructural pathology of gliomas. UA shows a detailed microenvironment of gliomas to reveal the abnormal presence of lipids in the intra- and extracellular environment of gliomas accompanied by the disrupted structure of the cellular membranes and organelles. The disruptions were noted in the blood vessels of the tumors displaying intriguing details regarding the formation of neovasculature and the absence of typical contents of vessel walls like endothelial cells. A comparative survey of the mitochondrial ultrastructure of gliomas with or without IDH1 mutations also reveals the role of UA in deciphering the impact of different mutations on the microenvironment level. Here, we also discuss the major implications of these findings regarding the research direction, diagnostic modalities, and therapeutic options.

Phenotypic and functional disparities in perivascular adipose tissue

The adipose tissue surrounding blood vessels is known as perivascular adipose tissue (PVAT), which represents a distinct ectopic fat depot that adheres to the majority of the vasculature. In recent years, owing to its unique location and function, PVAT has been regarded as a new type of adipose tissue distinct from traditional visceral fat. It releases adipokines with vasoconstrictive functions, which regulate vascular function through paracrine and endocrine mechanisms. Interestingly, PVAT can be categorized as white, brown or a mixture of both depending on its anatomical location. Brown adipose tissue (BAT) is located adjacent to the thoracic aorta in rodents, while a mix of brown and white tissue surrounds the abdominal aorta. PVAT exhibits regional phenotypic differences in different parts of the vasculature bed, which may lead to heterogeneity in the secretion profiles and norepinephrine (NE) content in regional PVAT and subsequently affect the regulation of specific adipokine signaling pathways in regional PVAT, resulting in differences in the regulation of vascular function. The aim of this review was to explore the potential factors that influence the anticontractile function of regional PVAT in the vasculature, including the heterogeneity of regional PVAT, the anticontractile function mediated by endothelial nitric oxide synthase (eNOS) in regional PVAT, the activity of the adiponectin-eNOS pathway in regional PVAT adipocytes, and the concentration of the sympathetic neurotransmitter NE in regional PVAT.

Examination of testicular veins in children with varicocele

BACKGROUND: Diagnostics and management of varicocele in children, adolescents and males are issues of annual discussions in the professional community, yet the debates still continue. Pathophysiological changes in the testicular veins in children with varicocele are dubious and require further in-depth fundamental researches. AIM: To study the difference in ultrastructural organization of testicular veins in boys with varicocele depending on the malformation degree. METHODS: In the present study, the authors examined the ultrastructure of 58 bioptats taken from spermatic veins during surgeries in adolescent boys aged 11–17 with varicocele of degree II and III. RESULTS: A comparative analysis of ultrastructural changes in the spermatic veins revealed that signs of endotheliocyte destruction of varying degree are met in 86% of biopsy samples in Group I and in 100% in Group II. Electron microscopy allowed to examine the muscular component of testicular veins in varicocele, as well as to examine the structure of connective tissue component in the venous wall, basing on an anatomical-functional paradigm of the connective tissue as the main "building brick" of organ and system structures. CONCLUSION: Ultrastructural changes in the testicular vein wall were revealed in children with varicocele, what indicates the presence of congenital malformation in this wall and of accompanied endothelial dysfunction. Foldings of the vascular wall with hollows and pockets, connective tissue loosening and separation of fibers, endothelium destruction and detachment were equally met in boys and adolescents with varicocele of degree II and III.

ROLE OF NF-κB ACTIVATION IN CHANGES OF NITRIC OXIDE PRODUCTION IN SKELETAL MUSCLES DURING METABOLIC SYNDROME

Nitric oxide, as a signaling molecule, plays an ambiguous role in many pathological processes. On the one hand, nitric oxide is necessary for maintaining the tone of the vascular wall of arteries and prevents the development of ischemia in various organs and skeletal muscles in particular. On the other hand, excessive production of nitric oxide in the tissue can contribute to the formation of toxic metabolites, such as peroxynitrite that leads to the development of nitrosative damage to various organs and tissues. Metabolic syndrome is also one of the diseases accompanied by disturbances in the nitric oxide production system. Currently, the sources of nitric oxide production, the predominant ways of its metabolism, and the influence of the transcription factor NF-κB on these processes in skeletal muscles under the conditions of the metabolic syndrome are insufficiently studied. The purpose of this study is to study the effect of an inhibitor of the activation of the transcription factor NF-κB on the production of nitric oxide and the concentration of its metabolites in the biceps femoris muscle of rats under the conditions of modeling the metabolic syndrome. The experimental study was carried out on male Wistar rats weighing 200-260 g. The animals were randomly divided into 4 groups of 6 animals each. Animals of group 1 (control group) received a standard vivarium diet. In group 2 (metabolic syndrome), in addition to the standard diet, the animals received a 20% fructose solution as their sole source of drinking water for 60 days. In group 3, the animals were given a standard vivarium diet and were injected intraperitoneally with ammonium pyrrolidine dithiocarbamate at a dose of 76 mg/kg, three times a week for 60 days. Group 4 received the same diet as group 2 along with the injections administered in group 3. In 10% homogenate of the biceps femoris muscle, the following were determined: total NO-synthase activity, activity of constitutive and inducible isoforms of NO-synthase, arginase activity, aitrate- and nitrite reductase activity, concentrations of nitrite, peroxynitrite, nitrosothiols, and sulfides. The administration of ammonium pyrrolidinedithiocarbamate during metabolic syndrome simulation resulted in a reduction in total NO-synthase activity and inducible NO-synthase activity by 33.85% and 34.66%, respectively, compared to the metabolic syndrome group; arginase activity decreased by 37.56%, while nitrate and nitrite reductase activities were reduced by 19.29% and 47.71%, respectively; nitrite concentration increased by 21.77%, peroxynitrite concentration decreased by 32.05%, nitrosothiol concentration increased by 29.27%, and sulfide concentration decreased by 17.39% compared to the group with metabolic syndrome. Activation of the transcription factor NF-κB under metabolic syndrome conditions leads to increased nitric oxide production through both L-arginine-dependent and L-arginine-independent pathways in the biceps femoris muscle, enhances arginase activity, and results in elevated peroxynitrite formation.

Risk assessment for rupture of brain arteriovenous malformations using high-resolution black-blood magnetic resonance imaging: a single-center case series.

Chronic inflammation's role in the pathogenesis, development, and rupture of vascular malformations is undebated. Advanced magnetic resonance imaging techniques with vessel wall studies, specifically Black Blood (bbMRI), may offer insights into vascular wall instability and predict rupture. This case series aims to assess bbMRI as a predictive diagnostic tool for brain arteriovenous malformations (bAVMs) rupture, suggesting early treatment. A prospective study included demographic, clinical, and neuroimaging data from a consecutive series of patients with ruptured or unruptured bAVMs, regardless of age or gender, between October 2018 and March 2024. All patients underwent MRI brain resonance with Black Blood study. Those with impaired renal function were excluded. Statistical analyses tested sample homogeneity. Univariate and multivariate logistical regressions assessed bbMRI as a rupture predictor for bAVMs, with a p-value set at < 0.05. Ninety patients were retrieved: 64 with unruptured and 26 with ruptured bAVMs. The mean age was 31.9 years, and 55 were female. Admission symptoms were headache, neurological deficits, and seizure in 49, 21, and 19 cases, respectively. bbMRI showed wall enhancement in 56 cases, with 19 in the ruptured and 37 unruptured groups. Univariate and multivariate analyses revealed a significant correlation between bbMRI wall enhancement and bAVM rupture (p:0.033; p:0.047). bbMRI may be a useful and feasible diagnostic implement to determine vessel inflammation and the bAVMs prone to rupture. Additional studies are needed to confirm the positive bbMRI as a predictive factor for bAVMs rupture.

Dynamics of ultrastructural changes in the yolk syncytial layer and its microenvironment during gastrulation and early postembryonic development of &lt;i&gt;Hemichromis Bimaculatus&lt;/i&gt;

BACKGROUND: In fish embryogenesis, the yolk sac is the critical provisional organ, actively functioning during the embryonic and early postembryonic stages. Its primary role is trophic, facilitated in Teleostei by a specialized structure — the yolk syncytial layer (YSL). Ultrastructural transformations of this layer during gastrulation and early postembryonic development, as well as its interaction with migrating muscle fibers and melanophores, are probably necessary for the efficient use of nutrients by the developing embryo. The yolk sac’s role in the embryogenesis of Hemichromis bimaculatus may extend beyond current conceptions. AIM: To study the structural organization of the Jewel Cichlid (H. bimaculatus) yolk sac during the embryonic and early postembryonic development. MATERIALS AND METHODS: The research was involved 22 embryos and larvae of H. bimaculatus from 1 to 7 days after egg laying. The morphological features of the yolk sac were studied using light and transmission electron microscopy. RESULTS: By day 2, the yolk sac was separated from the embryo by the trunk fold. Its main structure was the YSL, containing numerous nuclei, microvilli, mitochondria and phagolysosomes. The morphological features of the YSL were similar to those of the placental symplastotrophoblast and indicated high functional activity. The yolk sac mesenchyme contained blood vessels, migrating melanophores, and muscle fibers. The periderm, covered with a special shell, fuunctioned as the primary skin of the embryo. The transition to exogenous nutrition in Jewel Cichlid larvae was accompanied by a significant decrease in yolk sac size with its subsequent involution. CONCLUSIONS: The trophic function of the yolk sac in H. bimaculatus is mediated by the YSL, which, during gastrulation and postembryonic development, interacts with a number of structures present in the yolk sac wall. Migrating muscle fibers promote activation of yolk granules; accumulation of toxic metabolic products is associated with melanophores. The special structure of the periderm protects both the yolk sac and the embryo from external influences.