Vessel Morphology Research Articles

Feasibility, classification and potential clinical impact of non-invasive delineation of abdominal lymphatic vessels in patients following TCPC with T2 weighted MRI

Recent research in patients with functionally univentricular hearts (UVH) is focusing on pathologies of the lymphatic vessels. Morphology of the abdominal lymphatic vessels was analyzed by MRI in patients with UVH following total cavopulmonary connection (TCPC) and it was examined, if clinical and laboratory parameters correlate with changes after TCPC. We prospectively examined 33 patients at the age of 19.8 (14.6;30.2) years [median (Q1;Q3)] after TCPC (follow-up 14.3 years (9.7;24.9) with a heavily T2-weighted MRI sequence on a 3.0 T scanner. Examinations in coronal orientation were performed with respiratory gating, slice thickness 0.6 mm, TR 2400 ms, TE 692 ms, FoV 460 mm (covering thoracic and abdominal regions), scan time 14:41 min (13:18;16:30) after a solid meal and a cup of pineapple juice. The findings were classified according to delineation of abdominal lymphatic vessels. Type 1: <3 abdominal vessels (av) definable; type 2: 4–6 av definable; type 3: >6 av and/or oedematous changes or ascites. The results were correlated with parameters obtained at the annual routine check-up. Statistical analysis was performed using U-test and Chi-square test. Fifteen patients (group 1) showed type 3 lymphatic morphologies, two of which had ascites. Eighteen patients (group 2) showed lower grade morphologies (type 1–2). Image quality was rated considering the delineation of the common hepatic duct and did not differ between groups (p = 0.134). “Lymphatic burden” was automatically examined and was indexed to the number of delineated abdominal vessels and showed quantification according to the chosen categories type 1–3. Patients in group 1 were younger at MRI examination (17.4;14.3/18.9 vs. 26.2;18.2/32.3 years, p = 0.03). Superior cavopulmonary connection (SCPC) had been performed earlier in group 1 (9.9;7.9/25.5 vs. 29.2;13.7/66.6 months, p = 0.018). Laboratory examinations in group 1 showed lower levels for Immunoglobulin G (IgG), Lipase, α-Antitrypsin, Cystatin C and TSH. There were no significant differences for total protein, NTproBNP, lymphocytes or platelets. A history of chylothorax was present in 7/15 versus 2/18 p = 0.022. Protein-losing enteropathy (PLE) occurred in 4/15 versus 1/18 (p = 0.092). T2 weighted MRI is feasible for noninvasive delineation of abdominal lymphatic vessel in patients following TCPC. In the long-term follow-up, patients with more pronounced changes of the abdominal lymphatic vessels were younger at SCPC and were more likely to show a history of chylothorax and lower IgG values.

Deep learning for 3D vascular segmentation in hierarchical phase contrast tomography: a case study on kidney

Automated blood vessel segmentation is critical for biomedical image analysis, as vessel morphology changes are associated with numerous pathologies. Still, precise segmentation is difficult due to the complexity of vascular structures, anatomical variations across patients, the scarcity of annotated public datasets, and the quality of images. Our goal is to provide a foundation on the topic and identify a robust baseline model for application to vascular segmentation using a new imaging modality, Hierarchical Phase-Contrast Tomography (HiP-CT). We begin with an extensive review of current machine-learning approaches for vascular segmentation across various organs. Our work introduces a meticulously curated training dataset, verified by double annotators, consisting of vascular data from three kidneys imaged using HiP-CT as part of the Human Organ Atlas Project. HiP-CT pioneered at the European Synchrotron Radiation Facility in 2020, revolutionizes 3D organ imaging by offering a resolution of around 20 μm/voxel and enabling highly detailed localised zooms up to 1–2 μm/voxel without physical sectioning. We leverage the nnU-Net framework to evaluate model performance on this high-resolution dataset, using both known and novel samples, and implementing metrics tailored for vascular structures. Our comprehensive review and empirical analysis on HiP-CT data sets a new standard for evaluating machine learning models in high-resolution organ imaging. Our three experiments yielded Dice similarity coefficient (DSC) scores of 0.9523, 0.9410, and 0.8585, respectively. Nevertheless, DSC primarily assesses voxel-to-voxel concordance, overlooking several crucial characteristics of the vessels and should not be the sole metric for deciding the performance of vascular segmentation. Our results show that while segmentations yielded reasonably high scores-such as centerline DSC ranging from 0.82 to 0.88, certain errors persisted. Specifically, large vessels that collapsed due to the lack of hydrostatic pressure (HiP-CT is an ex vivo technique) were segmented poorly. Moreover, decreased connectivity in finer vessels and higher segmentation errors at vessel boundaries were observed. Such errors, particularly in significant vessels, obstruct the understanding of the structures by interrupting vascular tree connectivity. Our study establishes the benchmark across various evaluation metrics, for vascular segmentation of HiP-CT imaging data, an imaging technology that has the potential to substantively shift our understanding of human vascular networks.

Phenotypic and genetic characteristics of retinal vascular parameters and their association with diseases

Fundus images allow for non-invasive assessment of the retinal vasculature whose features provide important information on health. Using a fully automated image processing pipeline, we extract 17 different morphological vascular phenotypes, including median vessels diameter, diameter variability, main temporal angles, vascular density, central retinal equivalents, the number of bifurcations, and tortuosity, from over 130,000 fundus images of close to 72,000 UK Biobank subjects. We perform genome-wide association studies of these phenotypes. From this, we estimate their heritabilities, ranging between 5 and 25%, and genetic cross-phenotype correlations, which mostly mirror the corresponding phenotypic correlations, but tend to be slightly larger. Projecting our genetic association signals onto genes and pathways reveals remarkably low overlap suggesting largely decoupled mechanisms modulating the different phenotypes. We find that diameter variability, especially for the veins, associates with diseases including heart attack, pulmonary embolism, and age of death. Mendelian Randomization analysis suggests a causal influence of blood pressure and body mass index on retinal vessel morphology, among other results. We validate key findings in two independent smaller cohorts. Our analyses provide evidence that large-scale analysis of image-derived vascular phenotypes has sufficient power for obtaining functional and causal insights into the processes modulating the retinal vasculature.

Lutein Emulsion Stabilized by a Food-Grade Biopolymer Enhanced Lutein Bioavailability and Improved Retinal Vessel Morphology in Neonatal Rats with Retinopathy of Prematurity

BackgroundRetinopathy of prematurity (ROP) is a leading cause of blindness in infants, affecting 32% of hospitalized preterm babies. Oxidative stress, a primary pathogenic factor in ROP, triggers abnormal neovascularization of retinal vessels. Lutein, an antioxidant and the main component of macular pigment, is found in low levels in preterm infants and may help ameliorate ROP. However, its low bioavailability limits its application as a nutritional intervention. ObjectiveThe aim of the study was to assess the effect of a lutein emulsion stabilized by a food-grade biopolymer on lutein bioavailability in neonatal rats with ROP and examine the effects of both unemulsified lutein and lutein emulsion on the disease. MethodsNeonatal rats were subcutaneously administered KRN 633 (10 mg/kg BW) on postnatal days 7 and 8 (P7 and P8) to induce ROP. Neonatal rats that did not receive the treatment served as the control. From P9 to P21, both ROP and non-ROP rats were divided into three groups and given daily doses of olive oil, unemulsified lutein (2 mg/kg BW lutein), or lutein emulsion (2 mg/kg BW lutein). On P22, serum and tissues were collected. Lutein concentrations were measured using UPLC, and retinal morphology was assessed using immunohistochemistry. ResultsRats treated with lutein emulsion had significantly higher serum and tissue lutein concentrations than those receiving unemulsified lutein. Morphological assessments showed that ROP rats had more tortuous arteries, increased capillary density, enlarged vessels, reduced astrocyte density, and decreased neuronal cells. Both unemulsified lutein and lutein emulsion alleviated these abnormalities, with lutein emulsion showing superior efficacy in restoring neuronal cell levels to normal in the peripheral retina. ConclusionsLutein, in both unemulsified and emulsified forms, effectively inhibited ROP progression in neonatal rats. The biopolymer-based lutein emulsion showed promise as a delivery system to enhance lutein bioavailability and mitigate ROP in preterm infants.

Oseltamivir phosphate (Tamiflu) alters neurobehavior of zebrafish larvae by inducing mitochondrial dysfunction

Antiviral drugs are widely used, yet their potential risks during early development, particularly within the central nervous system, remain contentious. Oseltamivir phosphate (OSE), a commonly prescribed antiviral, is increasingly detected in various environments. However, its toxicity to organisms and the underlying mechanisms are not well understood. In this study, we employed the zebrafish model to evaluate the developmental neurotoxic effects of OSE at environmentally and therapeutically relevant doses, through high-throughput behavioral analysis, in vivo two-photon imaging, transcriptomic sequencing, pharmacological intervention, and biochemical and molecular assays. Our results indicated that OSE exposure increased heart rate and induced pericardial edema in zebrafish larvae. Additionally, OSE-exposed larvae exhibited hyperactive behavior, impaired social interactions, and reduced habitual learning capacity. Although OSE at our selected levels did not significantly affect neuron count in the brain, it activated neuroinflammatory responses, altered blood vessel morphology, modulated neurotransmitter levels and the expression of neurodevelopment-related genes. Transcriptomic analysis revealed upregulation of mitochondria-related genes associated with oxidative phosphorylation. Further assessments of mitochondrial function demonstrated altered activities of respiratory chain complexes, reduced mitochondrial membrane potential (MMP), and decreased ATP content. Notably, co-treatment with mitochondrial protectants acetyl-l-carnitine-hydrochloride (ALC) or nicotinamide riboside (NR) effectively mitigated OSE-induced neurobehavioral disorders. These findings suggest that overuse of OSE can pose neurodevelopmental risks for both humans and animals, potentially attributable to mitochondrial dysfunction.

Anatomical Structure and Bending Properties of Calamus zollingeri

The relationship between the structure and mechanical properties of materials has been a hot topic. However, there is a lack of research on the relationship between the structure of rattan and its mechanical properties. This study investigated the anatomical structure and bending properties of Calamus zollingeri, a commercially important rattan species. Samples were collected from different radial positions of the stem and analyzed for their microstructural features and mechanical properties. The distribution and morphology of vascular bundles (VBs), parenchyma cells (PCs), vessels, and fibers were examined using light microscopy. Bending tests were conducted to determine the modulus of rupture (MOR) and modulus of elasticity (MOE). Stepwise linear regression analysis was employed to explore the relationship between structural features and mechanical properties. The results showed that the diameters, lengths and distribution densities of the vessel elements were 280.32 μm, 2163.56 μm, and 3.68 pcs/mm2, respectively; the double wall thickness, lumen diameter, diameter, length, length–width ratio were 7.55 μm, 4.30 μm, 11.85 μm, 1569.39 μm, and 134.08, respectively; the tissue ratios of the vessel elements, fibers, sieve elements, and PCs were 22.76%, 20.5%, 4.83%, and 51.87%, respectively. The MOR of C. zollingeri was 55.77 MPa, while the MOE was 2669.11 MPa. The MOR of C. zollingeri was mainly affected by a double wall thickness of fiber and the tissue ratio of PCs, while the MOE was mainly affected by a double arm thickness of fiber and the tissue ratio of the vessel elements. This research provides valuable insights into the structure–property relationships of rattan, which can inform its optimal utilization in various applications.

VCU-Net: a vascular convolutional network with feature splicing for cerebrovascular image segmentation.

Cerebrovascular image segmentation is one of the crucial tasks in the field of biomedical image processing. Due to the variable morphology of cerebral blood vessels, the traditional convolutional kernel is weak in perceiving the structure of elongated blood vessels in the brain, and it is easy to lose the feature information of the elongated blood vessels during the network training process. In this paper, a vascular convolutional U-network (VCU-Net) is proposed to address these problems. This network utilizes a new convolution (vascular convolution) instead of the traditional convolution kernel, to extract features of elongated blood vessels in the brain with different morphologies and orientations by adaptive convolution. In the network encoding stage, a new feature splicing method is used to combine the feature tensor obtained through vascular convolution with the original tensor to provide richer feature information. Experiments show that the DSC and IOU of the proposed method are 53.57% and 69.74%, which are improved by 2.11% and 2.01% over the best performance of the GVC-Net among several typical models. In image visualization, the proposed network has better segmentation performance for complex cerebrovascular structures, especially in dealing with elongated blood vessels in the brain, which shows better integrity and continuity.

Лепная посуда могильника Алмалык-Дере

The article describes the molded dishes of the burial ground of the 4th-7th centuries. AD Almalyk-dere, located in the South-Western Crimea. A comparative typological analysis of this group of archaeological finds, in general, demonstrates its general cultural unity with molded dishes from other Crimean burial grounds of the late Roman and early medieval times, with the presence of certain differences. Common features are manifested in the technique and technology of production of stucco products, as well as in the composition and structure of the ceramic complex, and differences are in the morphology and ornamentation of vessels. The study of Almalyk molded dishes allows us to say that the emergence of the burial ground is associated with the arrival of a group of new population in southwestern Taurica, consisting of the numerically predominant Alans, as well as Germans and, obviously, some part of the Bosporans and late Scythians.

Lymphatic magnetic resonance imaging abnormalities in children with repaired tetralogy of Fallot.

Tetralogy of Fallot patients face an elevated risk of developing chylothorax and pleural effusions post-surgery. This patient group exhibits risk factors known to compromise the lymphatic system, such as elevated central venous pressure, pulmonary flow changes, and hypoxia. This study investigates the morphology and function of the lymphatic system in tetralogy of Fallot patients through lymphatic magnetic resonance imaging and near-infrared fluorescence imaging, respectively. Post-repair tetralogy of Fallot patients aged 6-18 years were recruited, along with age and gender-matched controls. Magnetic resonance imaging was used to assess the morphology of the thoracic lymphatic vessels and the thoracic, while near-infrared fluorescence imaging was used to assess lymphatic activity utilising lymph rate, velocity, and pressure. Nine patients and 10 controls were included. Echocardiography revealed that 2/3 of the patients had moderate-severe pulmonary regurgitation, while none displayed signs of elevated central venous pressure. Magnetic resonance imaging identified three patients with type 3 (out of 4 types) lymphatic abnormalities, while controls had none. The thoracic ducts showed severe (one patient) and moderate (one patient) tortuosity. Mean thoracic duct diameters were 3.3 mm ±1.1 in patients and 3.0 mm ± 0.8 in controls (p-value = 0.53). Near-infrared fluorescence imaging revealed no anomalous patterns. Despite no presence of clinical lymphatic disease, 3/9 of the repaired tetralogy of Fallot patients exhibited lymphatic morphological abnormalities. The significance of these anomalies remains uncertain currently. Further research is needed to determine whether these lymphatic alterations in this patient cohort are a result of congenital malformations, haemodynamic shifts, or prenatal and early-life saturation levels.

A fundus vessel segmentation method based on double skip connections combined with deep supervision.

Fundus vessel segmentation is vital for diagnosing ophthalmic diseases like central serous chorioretinopathy (CSC), diabetic retinopathy, and glaucoma. Accurate segmentation provides crucial vessel morphology details, aiding the early detection and intervention of ophthalmic diseases. However, current algorithms struggle with fine vessel segmentation and maintaining sensitivity in complex regions. Challenges also stem from imaging variability and poor generalization across multimodal datasets, highlighting the need for more advanced algorithms in clinical practice. This paper aims to explore a new vessel segmentation method to alleviate the above problems. We propose a fundus vessel segmentation model based on a combination of double skip connections, deep supervision, and TransUNet, namely DS2TUNet. Initially, the original fundus images are improved through grayscale conversion, normalization, histogram equalization, gamma correction, and other preprocessing techniques. Subsequently, by utilizing the U-Net architecture, the preprocessed fundus images are segmented to obtain the final vessel information. Specifically, the encoder firstly incorporates the ResNetV1 downsampling, dilated convolution downsampling, and Transformer to capture both local and global features, which upgrades its vessel feature extraction ability. Then, the decoder introduces the double skip connections to facilitate upsampling and refine segmentation outcomes. Finally, the deep supervision module introduces multiple upsampling vessel features from the decoder into the loss function, so that the model can learn vessel feature representations more effectively and alleviate gradient vanishing during the training phase. Extensive experiments on publicly available multimodal fundus datasets such as DRIVE, CHASE_DB1, and ROSE-1 demonstrate that the DS2TUNet model attains F1-scores of 0.8195, 0.8362, and 0.8425, with Accuracy of 0.9664, 0.9741, and 0.9557, Sensitivity of 0.8071, 0.8101, and 0.8586, and Specificity of 0.9823, 0.9869, and 0.9713, respectively. Additionally, the model also exhibits excellent test performance on the clinical fundus dataset CSC, with F1-score of 0.7757, Accuracy of 0.9688, Sensitivity of 0.8141, and Specificity of 0.9801 based on the weight trained on the CHASE_DB1 dataset. These results comprehensively validate that the proposed method obtains good performance in fundus vessel segmentation, thereby aiding clinicians in the further diagnosis and treatment of fundus diseases in terms of effectiveness and feasibility.

“Role Of Caroto-Vertebral Duplex Ultrasonography In Patients With Cerebro-Vascular Accident - Hemodynamic Characterisation &amp; Etiological Stratification”

Introduction: cerebrovascular accident is defined as a sudden, non convulsive focal neurological deficit resulting due to brain ischemia predominantly caused by the thrombo-embolism or with atheromatous carotid plaque as the embolic source1 . Cerebrovascular accident is the leading cause of morbidity in elderly patients with varying degrees of neurological deficit. Since it is a preventable condition and with timely intervention, the severity of the disease can be minimized. Hence, the aim of the present study was real time visualization of vascular lesions to characterize the morphology of vessels for intimal-media complex &amp; for any plaque or stenosis, to quantify the degree and percentage of stenosis in the caroto-vertebral arteries and to correlate the degree of stenosis with severity of clinical disease. Materials and methods: prospective cross-sectional study was conducted on 100 patients presenting with cva with or without persistent neurological deficit referred to department of radio-diagnosis and imaging from indoor and outdoor departments of jan sewa hospital of dr. S. S. Tantia medical college, sri ganganagar. Results: the majority of patients were in the age group of 60-69 years with 56% being male, 47% presenting with transient ischemic attack, commonest clinical feature being coronary artery disease (29%) followed by haeadache (17%), nausea vomiting (4%), hemiplegia (2%) patients and coma (1%). Hypertension was the most commonest risk factor (59%) followed by diabetes mellitus (18%), hyperlipidemia (14%), atrial fibrillations (5%) and smoking (4%). Majority of plaques were seen in the carotid bulb with variable laterality &amp; echopattern. It was seen that as the degree of stenosis increases the various velocities and their respective ratios (ica psv/ cca psv, ica edv/cca edv, ica psv/cca edv) tend to increase in proportion to the stenosis suggestive of a positive co-relation between them. Conclusion: caroto-vertebral duplex ultrasonography provides a “road map” for carotid endartectomy and/or carotid angioplasty and stenting due to direct visualization of plaque morphology &amp; surface configuration, measurement of the length of stenosed segment, precise determination of grade of stenosis and to get an insight into hemodynamic disorders.

Diabetic retinopathy data augmentation and vessel segmentation through deep learning based three fully convolution neural networks

ProblemThe eye fundus imaging is used for early diagnosis of most damaging concerns such as diabetic retinopathy, retinal detachments and vascular occlusions. However, the presence of noise, low contrast between background and vasculature during imaging, and vessel morphology lead to uncertain vessel segmentation. AimThis paper proposes a novel retinalblood vessel segmentation method for fundus imaging using a Difference of Gaussian (DoG) filter and an ensemble of three fully convolutional neural network (FCNN) models. MethodsA Gaussian filter with standard deviation σ1 is applied on the preprocessed grayscale fundus image and is subtracted from a similarly applied Gaussian filter with standard deviation σ2 on the same image. The resultant image is then fed into each of the three fully convolutional neural networks as the input. The FCNN models' output is then passed through a voting classifier, and a final segmented vessel structure is obtained.The Difference of Gaussian filter played an essential part in removing the high frequency details (noise) and thus finely extracted the blood vessels from the retinal fundus with underlying artifacts. ResultsThe total dataset consists of 3832 augmented images transformed from 479 fundus images. The result shows that the proposed method has performed extremely well by achieving an accuracy of 96.50%, 97.69%, and 95.78% on DRIVE, CHASE,and real-time clinical datasets respectively. ConclusionThe FCNN ensemble model has demonstrated efficacy in precisely detecting retinal vessels and in the presence of various pathologies and vasculatures.

Modeling Hemodynamics in Three-Dimensional, Biomimetic, Branched, Microfluidic, Vascular Networks.

Neovascularization has been extensively studied because of its significant role in both physiological processes and diseases. The significance of vascular microfluidic platforms lies in its essential role in recreating an in vitro environment capable of supporting cellular and tissue systems through the process of neovascularization. Biomechanical properties in a tissue engineered system use fluid flow and transport properties to recapitulate physiological systems. This enables mimicry of organ systems which can further personalized and regenerative medicine. Thus, fluid hemodynamics can be used to study these flow patterns and create a system that mimics real physiological pathways and processes. The establishment of stable flow pathways encourages endothelial cells (ECs) ECs to undergo neovascularization. Specifically, the shear stress applied in capillary beds generates the increased proliferation and differentiation of ECs to build larger microcirculatory beds. Here, we describe a mathematical model that uses branching patterns and vessel morphology to predict hemodynamic parameters in capillary beds. A retinal capillary bed is used as one-use case of our model to show how the mathematical framework can be used to determine hemodynamic parameters for any microfluidic system. In doing so, this tool can be altered to be used to supplement emerging research areas in neovascularization.

Towards Targeting Endothelial Rap1B to Overcome Vascular Immunosuppression in Cancer.

The vascular endothelium, a specialized monolayer of endothelial cells (ECs), is crucial for maintaining vascular homeostasis by controlling the passage of substances and cells. In the tumor microenvironment, Vascular Endothelial Growth Factor A (VEGF-A) drives tumor angiogenesis, leading to endothelial anergy and vascular immunosuppression-a state where ECs resist cytotoxic CD8+ T cell infiltration, hindering immune surveillance. Immunotherapies have shown clinical promise. However, their effectiveness is significantly reduced by tumor EC anergy. Anti-angiogenic treatments aim to normalize tumor vessels and improve immune cell infiltration. Despite their potential, these therapies often cause significant systemic toxicities, necessitating new treatments. The small GTPase Rap1B emerges as a critical regulator of Vascular Endothelial Growth Factor Receptor 2 (VEGFR2) signaling in ECs. Our studies using EC-specific Rap1B knockout mice show that the absence of Rap1B impairs tumor growth, alters vessel morphology, and increases CD8+ T cell infiltration and activation. This indicates that Rap1B mediates VEGF-A's immunosuppressive effects, making it a promising target for overcoming vascular immunosuppression in cancer. Rap1B shares structural and functional similarities with RAS oncogenes. We propose that targeting Rap1B could enhance therapies' efficacy while minimizing adverse effects by reversing endothelial anergy. We briefly discuss strategies successfully developed for targeting RAS as a model for developing anti-Rap1 therapies.

The iliac and femoral arteries: Dimensions and tortuosity in a South African radiological sample

BackgroundArterial morphology varies and changes with increasing age. This may challenge the success of endovascular procedures and influence candidate selection. The study aimed to determine the mean dimensions, tortuosity severity, and tortuosity phenotype of the iliofemoral pathway of adult males and females from a South African sample. Furthermore, the relationship between increased age and changes in vessel morphology was investigated. DesignA retrospective cross-sectional study was conducted using a sample of 224 (117 males and 107 females) computed tomography angiograms of patients hospitalized due to traumatic injuries (aged 18–80 years), accessed from Tygerberg Hospital, Cape Town, South Africa. MethodsThe arterial lengths and lumen diameters of the common iliac (CIA), external iliac (EIA), and femoral arteries (FA) were measured. Tortuosity severity was described by visual estimation and quantified using the tortuosity index (TI) and inflection count metric (ICM). The data were compared between right and left sides of the body, the sexes, and age categories. ResultsOn average, the common iliac artery was the widest (9.50 ± 1.53 mm), while the external iliac artery was the longest (110.89 ± 16.04 mm). Bilateral asymmetries were observed. Arterial diameters were larger in males. Regression analysis revealed a strong positive relationship between arterial tortuosity and increasing age, particularly in females. Tortuosity was most frequently observed in the external iliac artery. However, the c-shaped curving tortuosity phenotype was observed in all three arteries investigated. ConclusionThe morphology of the iliofemoral arterial pathway varied bilaterally, between the sexes, and with increased age. These findings align with previous studies, noting the variable morphology of the iliofemoral pathway, in countries outside of Sub-Saharan Africa. Sex- and age-specific descriptions of arterial anatomy may enhance the safety of endovascular procedures and interventions. These descriptions contribute towards the development of a reference database of typical arterial anatomy in South Africa, ultimately assisting with patient selection and the identification of vascular pathologies.

Loss of TGFβ-Mediated Repression of Angiopoietin-2 in Pericytes Underlies Germinal Matrix Hemorrhage Pathogenesis.

TGF (transforming growth factor)-β pathway is central to blood-brain barrier development as it regulates cross talk between pericytes and endothelial cells. Murine embryos lacking TGFβ receptor Alk5 (activin receptor-like kinase 5) in brain pericytes (mutants) display endothelial cell hyperproliferation, abnormal vessel morphology, and gross germinal matrix hemorrhage-intraventricular hemorrhage (GMH-IVH), leading to perinatal lethality. Mechanisms underlying how ALK5 signaling in pericytes noncell autonomously regulates endothelial cell behavior remain elusive. Transcriptomic analysis of human brain pericytes with ALK5 silencing identified differential gene expression. Brain vascular cells isolated from mutant embryonic mice with GMH-IVH and preterm human IVH brain samples were utilized for target validation. Finally, pharmacological and genetic inhibition was used to study the therapeutic effects on GMH-IVH pathology. Herein, we establish that the TGFβ/ALK5 pathway robustly represses ANGPT2 (angiopoietin-2) in pericytes via epigenetic remodeling. TGFβ-driven SMAD (suppressor of mothers against decapentaplegic) 3/4 associates with TGIF1 (TGFβ-induced factor homeobox 1) and HDAC (histone deacetylase) 5 to form a corepressor complex at the Angpt2 promoter, resulting in promoter deacetylation and gene repression. Moreover, murine and human germinal matrix vessels display increased ANGPT2 expression during GMH-IVH. Isolation of vascular cells from murine germinal matrix identifies pericytes as a cellular source of excessive ANGPT2. In addition, mutant endothelial cells exhibit higher phosphorylated TIE2 (tyrosine protein kinase receptor). Pharmacological or genetic inhibition of ANGPT2 in mutants improves germinal matrix vessel morphology and attenuates GMH pathogenesis. Importantly, genetic ablation of Angpt2 in mutant pericytes prevents perinatal lethality, prolonging survival. This study demonstrates that TGFβ-mediated ANGPT2 repression in pericytes is critical for maintaining blood-brain barrier integrity and identifies pericyte-derived ANGPT2 as an important pathological target for GMH-IVH.

GPER deficiency impedes murine myocutaneous revascularization and wound healing

Estrogens regulate numerous physiological and pathological processes, including wide-ranging effects in wound healing. The effects of estrogens are mediated through multiple estrogen receptors (ERs), including the classical nuclear ERs (ERα and ERβ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\upbeta }$$\\end{document}), that typically regulate gene expression, and the 7-transmembrane G protein-coupled estrogen receptor (GPER), that predominantly mediates rapid “non-genomic” signaling. Estrogen modulates the expression of various genes involved in epidermal function and regeneration, inflammation, matrix production, and protease inhibition, all critical to wound healing. Our previous work demonstrated improved myocutaneous wound healing in female mice compared to male mice. In the current study, we employed male and female GPER knockout mice to investigate the role of this estrogen receptor in wound revascularization and tissue viability. Using a murine myocutaneous flap model of graded ischemia, we measured real-time flap perfusion via laser speckle perfusion imaging. We conducted histologic and immunohistochemical analyses to assess skin and muscle viability, microvascular density and vessel morphology. Our results demonstrate that GPER is crucial in wound healing, mediating effects that are both dependent and independent of sex. Lack of GPER expression is associated with increased skin necrosis, reduced flap perfusion and altered vessel morphology. These findings contribute to understanding GPER signaling in wound healing and suggest possible therapeutic opportunities by targeting GPER.

Rapamycin increases murine lifespan but does not reduce mineral volume in the Matrix GLA Protein (MGP) knockout mouse model of medial arterial calcification.

Peripheral artery disease (PAD) is the narrowing of the arteries that carry blood to the lower extremities. PAD has been traditionally associated with atherosclerosis. However, recent studies have found that medial arterial calcification (MAC) is the primary cause of chronic limb ischemia below the knee. MAC involves calcification of the elastin fibers surrounding smooth muscle cells (SMCs) in arteries. Matrix GLA Protein (MGP) binds circulating calcium and inhibits vascular calcification. Mgp -/- mice develop severe MAC and die within 8 weeks of birth due to aortic rupture or heart failure. We previously discovered a rare genetic disease Arterial Calcification due to Deficiency in CD73 (ACDC) in which patients present with extensive MAC in their lower extremity arteries. Using a patient-specific induced pluripotent stem cell model we found that rapamycin inhibited calcification. Here we investigated whether rapamycin could reduce MAC in vivo using Mgp -/- mice as a model. Mgp +/+ and Mgp -/- mice received 5mg/kg rapamycin or vehicle. Calcification content was assessed via microCT, and vascular morphology and extracellular matrix content assessed histologically. Immunostaining and western blot analysis were used to examine SMC phenotypes and cellular functions. Rapamycin prolonged Mgp -/- mice lifespan, decreased mineral density in the arteries, and increased smooth muscle actin protein levels, however, calcification volume, vessel morphology, SMC proliferation, and autophagy flux were all unchanged. These findings suggest that rapamycin's effects in the Mgp -/- mouse are independent of the vascular phenotype.

Abstract We072: Effects of electronic cigarettes on mouse cardiac lymphatic vessels after TAC surgery

Introduction: Heart failure is a public health concern worldwide. It is known that tobacco smoking is a risk factor of heart failure. Tobacco smoking also causes inflammation reaction and lymphatic dysfunction in the lung. However, the effects of electronic cigarettes (ECIG), as a new method of smoking, on the heart and cardiac lymphatic vessels (lymphatics) are not clear yet. The lymphatic vessels play an important role in maintaining cardiac function by modulating fluid homeostasis and transporting macromolecules. It has been reported that cardiac lymphatic vessel formation limits pressure overload-induced heart failure in C57Bl/6 but not in Balb/c mice. How cardiac lymphatics might contribute to the pathogenesis induced by ECIG is not known. Research Questions: The roles of cardiac lymphatic vessels in responses to ECIG exposure are not investigated. I hypothesize that the toxic effects of ECIG on the heart are partially caused by damaging the cardiac lymphatic vessels. Aim: To determine the effects of ECIG exposure on cardiac lymphatics after Transverse aortic constriction (TAC). Methods: I perform TAC surgery on mice as a heart hypertrophy and chronic heart failure model. Mice after TAC or Sham surgery are treated with different vaping components from ECIG: ECIG, propylene glycol and glycerin (PGVG) as vehicle, and air. After 4 weeks of treatment, hearts were harvested for histological analyses. The lymphatic vessel coverage percentage and morphology were examined by immunostaining. Results: Prior research suggested that genetic background in mice might affect the responses of cardiac lymphatic vessels to TAC-induced heart failure. I have established the TAC model using CD-1 mice. My results showed that CD-1 mice treated with PGVG after TAC do not show a significant difference in cardiac lymphatic vessel density compared to Sham group (p value=0.5951). ECIG treatment also did not affect the lymphatic density significantly compared to PGVG treated mice after sham operation (p value=0.8937). ECIG treated mice after TAC surgery showed a trend of increased lymphatic coverage and more mice are still being processed and will be presented at the conference. Conclusion: PGVG treated CD-1 mice do not show changes in lymphatic vessel density 4 weeks post TAC. Longer time points and more mouse numbers are needed to compare the effects of PGVG and ECIG after TAC induced hypertrophy and heart failure. This research is supported by California TRDRP grant.

Dynamic optical coherence tomography for imaging acute wound healing.

The aim of this study was to investigate acute wound healing with dynamic optical coherence tomography (D-OCT). From 22 patients with 23 split skin graft donor sites, vessels at four wound edges, the wound bed, and adjacent and unaffected skin of the contralateral leg were measured by D-OCT at six time points from surgery to 4 weeks of healing. Changes in vessel orientation, density, diameter, morphology and pattern in horizontal, vertical and 3D images were analysed for wound healing and re-epithelialization. At 300 μm depth, there were significant differences of blobs and serpiginous vessels between normal and wounded skin. The wound had significantly more vertically oriented vessels, a higher degree of branching, vessel density and diameter compared with healthy skin. 3D images showed increased angiogenesis from healthy skin towards the wound centre, significantly higher vessel density at the wound than at normal skin and the highest at the interface. During wound healing blobs, coils and serpiginous vessels occurred significantly more frequently in lesional than healthy skin. Vessel density was greatest at the beginning, decreased and then increased by 4 weeks post-surgery. D-OCT helps to evaluate acute wound healing by visualizing and quantifying blood vessel growth in addition to re-epithelialization.