Capillary Research Articles

Stromal Hücrelerin Tarihçesi: İnterstisyel Cajal Hücrelerinden Telositlere - İnsan Telositlerine ve Olası İşlevlerine Kısa Bir Bakış

In the organ microenvironment stromal cells make up an essential population, however research on them has been very limited. The stroma mainly consists of fibroblasts that reside together with mesenchymal cells, endothelial cells, pericytes, neurons, adipocytes, immune cells etc. The different morphologies and functional properties of stromal cells have led to subclassification of different cell types in connective tissue. Among them are the interstitial cells of Cajal and telocytes. Telocytes are one of the newer cells known for their small cell bodies and long telopods and have been recently identified in the connective tissue of many organs. Telocytes are strategically positioned near nerve endings, around blood capillaries and in close relation with particular cells. The network of telocytes is engaged in integrating information from multiple sources and coordinating the tissue homeostasis in response to the tissues local functional requirements. Extracellular vesicles provide a means of bidirectional communication, and their secretome appears to control the mechanisms of stem cell differentiation. Telocytes have been identified in various organs, specifically in human heart, lungs, brain, eye, thyroid, skeletal muscles, skin, salivary glands, gastrointestinal tract, pancreas, gallbladder, liver, and organs of the male and female urogenital system. Additionally, given the heterogeneity of the organs in which telocytes are found, and their capability to play a role in the etiopathogenesis of various diseases, the concept of "telocytopathies" has emerged. In conclusion, telocytes are increasingly becoming a focal point for the understanding of idiopathic diseases that affect humans as well as the development of new diagnostic and therapeutic approaches, and they have the potential to contribute to regenerative medicine.

AIENP‐Reinforced DISCO Method for Whole‐Tissue 3D Reconstruction of Pulmonary Capillaries

AbstractThe pulmonary vascular system plays a crucial role in maintaining normal physiological functions, and perturbations in this network often serve as indicators for various fatal diseases. Thus, accurate mapping and assessment of the intricate anatomical details of pulmonary vasculature is essential for the investigation of the underlying mechanism of these diseases. Yet it is considered a tough challenge as traditional imaging techniques offer limited representations of the vasculature network in the lung, while optical imaging methods face limitations from tissue depth. To overcome these obstacles, in this study, an AIENP‐reinforced DISCO method, for whole‐tissue 3D reconstruction of pulmonary capillaries is presented. Combining AIENPs, hydrogel‐enhanced scaffolds, and solvent‐based DISCO procedures, the method successfully visualizes the entire network of mouse pulmonary capillaries with a significantly shortened timeframe and cost. The whole process including labeling and clearing takes 6 days and it costs ≈ 5 USD to stain the lung vasculature of an adult mouse. Moreover, the study provides valuable insights for detecting pulmonary vascular abnormalities. This fast and cost‐effective technique opens new avenues for developing better fluorophores compatible with tissue optical clearing and offers insights for in‐depth research on pulmonary pathophysiology.

Challenges towards an acceleration in stellarator reactors engineering: The dual coolant lithium–lead breeding blanket helical-axis advanced stellarator case

Under the ambitious EUROfusion mission of “bringing the stellarator line to technological maturity”, the development of a Dual Coolant Lithium–Lead (DCLL) Breeding Blanket (BB) for a Helical-Axis Advanced Stellarator (HELIAS) started. The BB is the crucial systems to achieve tritium self-sufficiency in fusion power plants. The DCLL has potentialities to answer the challenges posed by complex HELIAS configuration, having liquid breeder and decoupled first wall (FW) and breeding zone circuits. Both characteristics are being empowered to simplify remote maintenance and integration of the BB segments. Hence, a “quasi-toroidal” BB segmentation has been proposed to minimize the magnetohydrodynamic pressure drop eschewing complex electrical insulating components while hindering maintenance. Such controversy motivated the use of a detached FW small panels manageable through ports. On this basis, a decoupled Capillary Porous System FW has been assessed under thermal-hydraulics and neutronics point of view. Moreover, ad-hoc tools have been developed for the parametrization of models and convergence toward a viable DCLL HELIAS design, speeding-up the coupling of computer-aided design modelling and analyses. Such novel strategies are described in view of a potential acceleration of the stellarator reactor engineering and by providing an overview of the stellarator challenges inside a global context.

Acute brain injury increases pulmonary capillary permeability via sympathetic activation-mediated high fluid shear stress and destruction of the endothelial glycocalyx layer

Neurogenic pulmonary edema secondary to acute brain injury (ABI) is a common and fatal disease condition. However, the pathophysiology of brain-lung interactions is incompletely understood. This study aims to investigate whether sympathetic activation-mediated high fluid shear stress after ABI would damage pulmonary endothelial glycocalyx thus leading to increased pulmonary capillary permeability. The tricuspid annular plane systolic excursion (TAPSE) was detected in a rat model of controlled cortical impact (CCI) and CCI + transection of the cervical sympathetic trunk (TCST). Changes in pulmonary capillary permeability were assessed by analyzing the Evans blue, measuring the dry/wet weight ratio of the lungs and altering protein levels in the bronchoalveolar lavage fluid (BALF). The parallel-plate flow chamber system was used to simulate the fluid shear stress in vitro. Western blotting and immunofluorescence staining were used to determine the expression levels of hyaluronan-binding protein (CEMIP), syndecan-1 and tight junction proteins (TJPs, including claudin-5 and occludin). TCST could restrain cardiac overdrive and sympathetic activation in a rat model of CCI. Compared to the CCI group, the CCI + TCST group showed a reduction of CEMPI (which degrades hyaluronic acid), along with an increase of syndecan-1 and TJPs. CCI + TCST group presented decreasing pulmonary capillary permeability. In vitro, high shear stress (HSS) increased the expression of CEMIP and reduced syndecan-1 and TJPs, which was coordinated with the results in vivo. Our findings show that sympathetic activation-mediated high fluid shear stress after ABI would damage pulmonary endothelial glycocalyx thus leading to increased pulmonary capillary permeability.

A case of plasmacytoma with widespread metastasis in a dog

In this study, a case of plasmacytoma with widespread metastasis in a nine-year-old male Rottweiler dog was described by histopathological and immunohistochemical methods. Macroscopic examination revealed multifocal white or pink-red colored masses ranging in size from 0,5 to 3 cm in the lung, liver, mediastinal and mesenterial lymph nodes, spleen, heart, pancreas, intestine and kidneys. In microscopic examination, tumor foci consisting mostly of atypical plasma cells were observed in the lung, liver, spleen, pancreas, mediastinal and mesenteric lymph nodes, intestine, and kidneys. Tumor-type giant cells were observed in tumor foci in the lung, mitotic figures in tumor foci in other organs, including the lung, and abundant tumor cells in capillary vessels. In Methyl Green Pyronin staining of lung, liver, spleen, pancreas, mediastinal and mesenterial lymph nodes, intestine and kidney sections, the cytoplasm of plasma cells was observed to be stained pink. Congo Red staining applied to liver and spleen sections showed amyloid deposits stained in brick red color. In addition, in the immunohistochemical staining of lung, liver, spleen, pancreas, mediastinal and mesenterial lymph nodes, intestine and kidney sections with Proliferating Cell Nuclear Antigen (PCNA) antibody, severe immunoreactivity was detected in tumor cells. As a result, due to the presence of rarely reported widespread metastases in the lung, liver, spleen, pancreas, mediastinal and mesenterial lymph nodes, intestine and kidneys of the diagnosed plasmacytoma case, it was deemed appropriate to publish the case in order to contribute to the literature by attracting the attention of veterinarians.

Evaluation of the Histomorphology of Small Intestine of Wistar Rats Exposed to Eliozu Dumpsite Leachate

This study is aimed to evaluate the histomorphology of small intestine of Wistar rats exposed to Eliozu dumpsite leachate. The toxic effect of Eliozu dumpsite leachate has been studied, where the researcher has identified that the leachate has toxicological effects on some organ tissues like the blood, reproductive tracts and hormones, oxidative stress parameters and the cerebral cortex. Twenty-five female Wistar rats weighing between 120-140 g were obtained from the animal house unit of Faculty of Basic Medical Sciences, University of Port Harcourt, Nigeria. The rats were randomly assigned into five groups of five (5) rats in each group. Group 1 served as a control and orally received 1 ml of bottled water; group 2 orally received 1 ml of water from a borehole close to the dumpsite. Groups 3, 4 and 5 received 1 ml of 10%, 50%, and 100% leachate concentrations orally for 30 days. In the present study, an alteration in the histoarchitecture of the small intestine of the Eliozu dumpsite leachate treated animals was observed; the small intestine of the control group has shown normal intestinal histoarchitecture. The mucosa forms a series of finger-like villi, each showing lamina propria, blood capillaries etc. the simple columnar mucosal epithelium contains absorptive goblets cells, crypts of Liberkuhn in the mucosa and Brunner’s glands. It is concluded that exposure to the Eliozu dumpsite leachate and the consumption of the nearby borehole water with significant heavy metals and microorganism have caused the histopathological alterations in gastrointestinal tracts (small intestines) of animals and it is recommend that Government and environmental regulatory agencies find an ecofriendly method to treat Eliozu dumpsite leachate.

Morphological changes in the wall of the urinary bladder under the conditions of using epirubicin and dimethyl sulfoxide

Annotation. The paper presents morphological and morphometric data on the changes in the bladder wall of rats under the action of the chemopreparation epirubicin in combination with dimethyl sulfoxide, which was used to increase the permeability of the medicinal agent through the mucous membrane of the bladder. The study was conducted on female inbred white rats weighing 250-300 g. The following were determined: the thickness of the mucous membrane of the urinary bladder, the specific weight of damaged and restored cells of the bladder epithelium, the specific weight of the arterial and venous components of the hemomicrocirculatory bed (layer by layer), the specific weight of the area of blood capillaries in the submucosa and the muscle membrane, the Kernohan' index for arterioles and venule of the microcirculatory channel of the bladder wall. The statistical processing of the results was carried out in the “STATISTICA 5.5” package (owned by the Central Scientific Research Institute of National Pirogov Memorial Medical University, Vinnytsya, license No. АХХР910A374605FA) using parametric data evaluation methods. The reliability of the difference in mean values was determined based on the Student's t test. The obtained data indicate less significant disturbances on the side of the bladder wall when using the complex with dimethyl sulfoxide and the absence of strong fibrosis of the submucosal base.

MHD Flow in Simple Cubic Periodic Array Geometry

The aim of this study is to investigate the behaviour of liquid metal flow in Capillary Porous System (CPS) under strong external magnetic field. Overlapping simple cubic (SC) periodic array of electrically non-conducting spheres with diameter 6 mm and distance between spheres centres 5.6 mm is 3D printed from PLA electrically non-conducting filament. At room temperature, flow of up to 50 mL/s of In–Ga–Sn in pore space in magnetic field of superconducting magnet up to 5T is investigated. Three orientations of magnetic field in relation to the main flow in SC cell are considered—colinear with main flow and perpendicular to it. The values of Reynolds, Hartmann and Stuart numbers in experiment are up to 1160, 90 and 350, respectively. The results indicate that parallel to the main flow orientation of magnetic field has little influence on the flowrate, while perpendicular orientation strongly reduces flowrate with dependence close to 1/Ha, which agrees well with ANSYS Fluent simulations in a unit SC cell, resembling results for channel flow in magnetic field.

Summary of the application value of ultrasound imaging features in the clinical differential diagnosis of intramuscular capillary-type hemangioma and fibro-adipose vascular anomaly.

To investigate the value of ultrasonography as a diagnostic aid in differentiating intramuscular capillary-type hemangioma (ICTH) from fibro-adipose vascular anomaly (FAVA). A retrospective analysis was conducted of the clinical and ultrasound imaging data of 20 patients with ICTH and 45 patients with FAVA who were admitted to and pathologically confirmed in hospital between January 2013 and April 2023. The clinical and ultrasonographic appearances of the lesions in the two groups were compared and analyzed. A stepwise regression analysis was performed, and a joint diagnostic equation was constructed using the final variables selected. The receiver operating characteristic (ROC) curve and indicators, including sensitivity and specificity, were used to evaluate the efficacy of the joint diagnostic model. The two groups of patients suffering from ICTH and FAVA presented a statistically significant difference (P< 0.05) in terms of 'age', 'lesion size', 'fascial tail sign', 'presence of a fatty-tissue-like hyperecho around the lesion', 'blood flow' and 'presence of straight blood capillaries within the lesion'. Finally, the variables 'fascial tail sign' and 'presence of straight blood capillaries within the lesion' were selected to construct the model. The constructed joint diagnostic model had a sensitivity value of 70.0% (95% CI: 59.00-81.00), a specificity value of 98.0% (95% CI: 94.70-100.00) and a ROC curve value of 0.908, indicating the high efficacy of the combined diagnosis method. Ultrasonography can be utilized to differentiate ICTH from FAVA, and the combined diagnosis method can further improve the technique's diagnostic efficacy.

32-year-old diabetic patient with progressive vision loss and crystalline retinopathy.

To report the case of severe bilateral retinal vascular occlusion in a patient with hyperoxalosis and chronic renal failure. Observational case report. Medical and imaging records were retrospectively reviewed. The patient was imaged with ultra-widefield (UWF) fundus photography and fluorescein angiography (UWF-FA), cross sectional and en face spectral-domain optical coherence tomography (SD-OCT), and OCT angiography. A 32-year-old diabetic patient receiving peritoneal dialysis was referred because of severe vision loss. UWF color fundus photography showed diffuse sclerotic retinal vessels and diffuse intraretinal crystals in both eyes. UWF-FA illustrated near-complete retinal vascular occlusion and capillary wipe out in both eyes. SD-OCT demonstrated diffuse inner and middle retina thinning in both eyes and multiple intraretinal hyperreflective foci consistent with crystalline deposits in all retina layers of both eyes. OCT angiography revealed severe capillary and large vessel non-perfusion in the superficial and deep retinal capillary plexus of each eye. The serum oxalate levels were increased at 28 µmol/L (reference range < 2 µmol/L) and genetic testing was positive for a heterozygous mutation of the AGXT (Alanine-Glyoxylate Amino Transferase) gene that causes type 1 autosomal recessive primary hyperoxaluria. A diagnosis of hyperoxalosis causing severe retinal vascular occlusion was rendered. Hyperoxalosis was the result of multiple factors including heterozygous AGXT mutation, chronic renal failure insufficiently treated with peritoneal dialysis, and a diet high in oxalate. This case highlights the importance of ruling out retinal oxalosis in patients on peritoneal dialysis in order to initiate prompt hemodialysis and prevent severe retinal vascular occlusion.

Penile cavernous sinusoids are Prox1-positive hybrid vessels.

Endothelial cells (ECs) of blood and lymphatic vessels have distinct identity markers that define their specialized functions. Recently, hybrid vasculatures with both blood and lymphatic vessel-specific features have been discovered in multiple tissues. Here, we identify the penile cavernous sinusoidal vessels (pc-Ss) as a new hybrid vascular bed expressing key lymphatic EC identity genes Prox1, Vegfr3,and Lyve1. Using single-cell transcriptome data of human corpus cavernosum tissue, we found heterogeneity within pc-S endothelia and observed distinct transcriptional alterations related to inflammatory processes in hybrid ECs in erectile dysfunction associated with diabetes. Molecular, ultrastructural, and functional studies further established hybrid identity of pc-Ss in mouse, and revealed their morphological adaptations and ability to perform lymphatic-like function in draining high-molecular-weight tracers. Interestingly, we found that inhibition of the key lymphangiogenic growth factor VEGF-C did not block the development of pc-Ss in mice, distinguishing them from other lymphatic and hybrid vessels analyzed so far. Our findings provide a detailed molecular characterization of hybrid pc-Ss and pave the way for the identification of molecular targets for therapies in conditions of dysregulated penile vasculature, including erectile dysfunction.

Combination of intraoperative indocyanine green video-angiography FLOW 800 and computed tomography perfusion to assess the risk of cerebral hyperperfusion syndrome in chronic internal carotid artery occlusion patients after revascularization surgery.

To study the changes of corticocerebral hemodynamics in surgical area and postoperative hyperperfusion syndrome in patients with chronic internal carotid artery occlusion (CICAO) by intraoperative indocyanine green videoangiography (ICGA)-FLOW 800 and CT perfusion after superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery. From October 2019 to January 2021, 77 patients diagnosed with CICAO underwent direct bypass surgery at Huadong hospital (affiliated with Fudan University) were enrolled. Regions of interest (ROIs) at STA, proximal MCA (PMCA), distal MCA (DMCA), cortical blood capillary (CBC), and cortical vein (CV) were identified after anastomosis by ICGV-FLOW 800 including peak fluorescence intensity (PFI), time to peak (TTP), and area under the time curve (AUC) of fluorescence intensity. All patients underwent perfusion-weighted CT before bypass surgery and those patients with HPS were verified by CTP after bypass. 14 patients with HPS were verified by perfusion-weighted CT after bypass. In HPS group, the AUCTTP of DMCA was significantly larger (T = -3.301, p = 0.004) and TTP of CBC was shorter (T = -2.929, p = 0.005) than patients in non-HPS group. The larger AUCTTP of DMCA (OR = 3.024, 95%CI 1.390-6.578, p = 0.0050) was an independent risk factor by further multivariate logistic regression analysis. The hemodynamic changes of cortical vessels during STA-MCA bypass surgery could be recorded accurately by ICGV-FLOW 800. Furthermore, the increased AUCTTP of DMCA and shorter TTP of CBC may be potential risk factors of HPS.

Artificial intelligence and hemodynamic studies in optical coherence tomography angiography for diabetic retinopathy evaluation: A review.

Diabetic retinopathy (DR) is a rapidly emerging retinal abnormality worldwide, which can cause significant vision loss by disrupting the vascular structure in the retina. Recently, optical coherence tomography angiography (OCTA) has emerged as an effective imaging tool for diagnosing and monitoring DR. OCTA produces high-quality 3-dimensional images and provides deeper visualization of retinal vessel capillaries and plexuses. The clinical relevance of OCTA in detecting, classifying, and planning therapeutic procedures for DR patients has been highlighted in various studies. Quantitative indicators obtained from OCTA, such as blood vessel segmentation of the retina, foveal avascular zone (FAZ) extraction, retinal blood vessel density, blood velocity, flow rate, capillary vessel pressure, and retinal oxygen extraction, have been identified as crucial hemodynamic features for screening DR using computer-aided systems in artificial intelligence (AI). AI has the potential to assist physicians and ophthalmologists in developing new treatment options. In this review, we explore how OCTA has impacted the future of DR screening and early diagnosis. It also focuses on how analysis methods have evolved over time in clinical trials. The future of OCTA imaging and its continued use in AI-assisted analysis is promising and will undoubtedly enhance the clinical management of DR.

Study of Sorption of Chlortetracycline Hydrochloride and Its Subsequent Determination by Capillary Zone Electrophoresis

The work deals with the development of an approach to the determination of chlortetracycline, which combines the preconcentration of the analyte with its subsequent determination by capillary zone electrophoresis. The conditions that ensure the lowest value of the limit of determination for chlortetracycline in aqueous solutions using a Kapel-105M capillary electrophoresis system (Lumex, Russia) are determined, i.e., temperature, time and pressure of sample injection, background electrolyte composition, and detection wavelength. It is shown that the stability of a chlortetracycline solution is maximum at a storage temperature of 0.5°С in the absence of buffer systems or in using a dilute ammonium acetate buffer solution. It is found that the recovery of chlortetracycline by strongly acidic cation exchangers KU-1, KU-2 is higher compared to that by KB-4 and KB-4P2, bearing weakly acidic functional groups. The conditions under which the recovery of the analyte by KU-1 from a phosphate buffer solution is about 90% are determined.

Cochlear Implantation with Fontan Circulation: A Rare Case of Non-Cardiac Pediatric Surgery

Background: Fontan circulation is a cardiac circulation following the Fontan procedure in patients with a single ventricle congenital heart defect. This circulation depends on the difference in pressure between pulmonary capillaries and central venous pressure to achieve optimal cardiac output. This case report aims to discuss intraoperative anesthesia management in a patient with Fontan circulation undergoing a non-cardiac surgical operation.&#x0D; Case presentation: The patient is a 7-year-old male with a history of congenital heart disease who has undergone the Fontan circulation procedure and is now undergoing Cochlear implantation surgery. The patient was managed with general anesthesia - endotracheal intubation and controlled ventilation during the operation, following the principle of minimizing intrathoracic positive pressure, low PEEP, and low tidal volume with a target peripheral saturation &gt; 95%. Cardiac output monitoring during the intraoperative period is done using intra-arterial blood pressure. After 5 hours of surgery, the patient was extubated with stable hemodynamics. &#x0D; Conclusion: The primary goal of intraoperative anesthesia management in patients with Fontan circulation is to maintain an optimal transpulmonary gradient by ensuring optimal transpulmonary blood flow, thus preserving cardiac output.

Spatiotemporal Impact of Sars-Cov-2 Infection on the Transcriptome of Bone Marrow Megakaryocytes

Megakaryocytes, integral to platelet production, predominantly reside in the bone marrow, undergoing regulated fragmentation within sinusoid vessels to release platelets into the bloodstream. Inflammatory states and infections have been shown to influence megakaryocyte transcription, potentially affecting platelet functionality. Notably, COVID-19 has been associated with altered platelet transcriptome. In this study, we hypothesized that SARS-CoV-2 infection could impact the transcriptome of bone marrow megakaryocytes, particularly those in direct proximity to the blood. Utilizing spatial transcriptomic analysis and machine learning techniques, we observed that the transcriptome of healthy mouse bone marrow megakaryocytes exhibited minimal alteration based on proximity to sinusoid vessels. Similar findings were observed during peak SARS-CoV-2 viremia, when the disease primarily affected the lungs. Conversely, a significant divergence in the transcriptome of megakaryocytes was observed during systemic inflammation, even when SARS-CoV-2 was no longer detectable in the lungs or bone marrow. Under these conditions, the transcriptional landscape was enriched in genes associated with structural and translational activities, platelet degranulation, netosis, and auto-immunity. Of the approximately ~19,000 genes identified in megakaryocytes during systemic inflammation, machine learning pinpointed 30 genes significantly altered in cells closely adjacent to sinusoid vessels, with gene ontology attributing these changes primarily to protein deSUMOylation. Intriguingly, the type-I interferon signature and calprotectin (S100A8/A9) were not induced under any condition. Inflammatory cytokines were elevated in the blood of COVID-19 mice, but not in bone marrow plasma, suggesting a preferential impact of inflammation on this specific subset of cells. Collectively, our data indicate that distinct subpopulations of bone marrow megakaryocytes may emerge based on spatial localization and the stage of COVID-19 pathogenesis.

Interferons Prime Endothelium for TLR-Mediated Prothrombotic Transformation

Cytokine storm occurs with respiratory infection and is associated with microvascular thrombosis. However, the cytokines responsible for promoting thrombus formation in the pulmonary microvasculature and the mechanisms by which they act are largely unknown. In its initial response to invading viruses or bacteria, pulmonary epithelium and macrophages release a variety of cytokines into the pulmonary circulation. With progressive invasion, the fragile barrier between alveolus and pulmonary capillaries breaks down and endothelial cells are exposed to pathogen-associated molecular patterns (PAMPs), which stimulate endothelial toll-like receptors (TLRs). To identify the cytokines that stimulate endothelial prothrombotic activity, we screened MIP-1β, MCP-1, IL-10, IL-6, IL-1β, TNFα, IFNα, IFNβ, and IFNγ for their ability to synergize with PAMPs in order to stimulate thrombin generation on endothelium. Dose curves showed that IFNs and TNFα were ~1000-fold more potent than the other cytokines at priming endothelium for thrombin generation induced by poly(I:C), a synthetic PAMP that stimulates TLR3 ( Fig. 1). Anti-tissue factor (TF) antibody completely attenuated thrombin generation induced by either IFNα or IFNγ exposure followed by poly(I:C) stimulation. Evaluation of TF expression and FXa generation showed that although exposure of endothelium to IFNs did not itself enhance TF expression or activity, IFNs substantially augmented TF expression and activity in response to poly(I:C). In addition, IFNα and IFNγ significantly inhibited thrombomodulin expression, even in the absence of poly(I:C). To evaluate whether or not IFNs enhance thrombin generation in endothelium stimulated through TLRs other than TLR3, we exposed endothelium to IFNα or IFNγ, followed by stimulation with different TLR-selective agonists. IFNγ exposure enhanced thrombin generation on endothelium in response to the TLR1/2 agonist PAM3CSK4, but IFNα did not have a significant effect, indicating the specificity of coupling to a particular IFN subtype. In contrast, the stimulation of endothelial thrombin generation by the TLR3 agonists, poly(I:C) and poly(A:U), was more potently enhanced by IFNα compared to IFNγ. Stimulation of thrombin generation by TLR4 agonists, including LPS and CRX-527, was significantly enhanced by IFNγ, but not IFNα. This coupling of IFNα with TLR3 agonists is consistent with the known association of viral infection with IFNα stimulation and TLR3 activation. Coupling of IFNγ with TLR2/4 agonists reflects a previously identified association of bacterial infection with both IFNγ stimulation and TLR 2 and 4 activation. Evaluation of conditioned media from pulmonary epithelial cells showed that media from inflamed pulmonary epithelial cells, but not quiescent epithelium, primed endothelium for substantial thrombin generation in response to poly(I:C). Anti-IFNα antibodies blocked the priming effect of inflamed condition media. These studies show that endogenous IFNs elaborated by pulmonary epithelium prime endothelium for TLR-mediated thrombin generation. These results show that IFNs are both necessary and sufficient to enhance TLR-mediated endothelial thrombin generation and provide a new framework for understanding the role of IFNs in cytokine-related thrombus formation ( Fig. 2). This model indicates that endothelial cells possess a verification system wherein a robust thrombotic response is only initiated if the type of IFN released by alveolar macrophages and epithelium is consistent with the type of TLR sensed by the endothelium. These observations provide a mechanistic basis for microvascular thrombosis in cytokine storm and raise the possibility of targeting interferons to prevent thrombotic complications in this setting.

Vascular Cell Adhesion Molecule-1 Regulates Bone Marrow Mesenchymal Stem Cell Maintenance and Niche Function

Bone marrow (BM) mesenchymal stem cells (MSCs) are rare non-hematopoietic perivascular stromal cells characterized by their unique ability to self-renew and differentiate into bone, cartilage, and fat, ensuring proper skeletal development and maintenance. Different subsets of BM MSCs associate with arteriolar and sinusoidal vessels to form specialized niches that regulate hematopoietic stem cell (HSC) function by secreting high levels of niche factors such as CXC-chemokine ligand 12 (CXCL12), stem cell factor (SCF), and Vascular Cell Adhesion Molecule-1 (VCAM1). VCAM1 is classically expressed on endothelial and stromal cells where it acts as an adhesion molecule that preferentially binds to α4β1 integrin on HSCs and progenitor cells (HSPCs). Deletion of Vcam1 in endothelial and hematopoietic cells induces HSPC mobilization into the peripheral blood without affecting endothelial cells homeostasis. Recent work from our lab further demonstrated that VCAM1 expression on HSCs and leukemic stem cells confers innate immune tolerance ( Nat Cell Biol 2022). While the contribution of HSC and endothelial-derived VCAM1 to homeostasis has been well studied, the role of MSC-derived VCAM1 on HSC and MSC maintenance and multilineage potency remains unknown. Our supporting data suggest that MSCs are the BM's main source of Vcam1 (p&amp;lt;0.0001) and that VCAM1 is critical for the maintenance, survival, and function of MSCs. Using a mouse model in which Vcam1 can be conditionally deleted in BM MSCs by a tamoxifen-inducible N-Cadherin-Cre ER line (referred to as Vcam1 N-CadCreER), we found that deletion of Vcam1 significantly reduces the number (4-fold, p=0.0030), frequency (4-fold, p=0.0042), and viability (2-fold, p=0.0039) of BM MSCs. Previous findings in breast cancer revealed that VCAM1 promotes PI3K/Akt survival signaling via Akt phosphorylation. Accordingly, Vcam1 deletion in N-Cadherin-Cre ER MSCs, demonstrated a significant reduction in phospho-Akt (Ser473) (p&amp;lt;0.05), supporting the role of VCAM1 in mediating PI3K/Akt survival signaling in MSCs. Intriguingly, the remaining viable VCAM1-null MSCs isolated from Vcam1 N-CadCreER mice exhibited reduced clonogenic potential (determined by CFU-F assays; 3-fold, p=0.0001). Furthermore, micro-CT analysis of 6-month-old Vcam1 N-CadCreER mice presented an altered bone phenotype compared to the control as evidenced by their significantly increased bone thickness and volume (p&amp;lt;0.05), yet significantly decreased tissue mineral density and medullary cavity area (p&amp;lt;0.05). Bulk RNA sequencing (RNAseq) of sorted viable MSCs revealed distinct grouping between Control and Vcam1 N-CadCreER MSCs. Gene ontology analysis demonstrated that deletion of Vcam1 caused an upregulation of pathways associated with inflammation and cytokine release while pathways associated with ossification, extracellular matrix organization, and skeletal development were all downregulated. Surprisingly, both bulk RNAseq and qPCR analysis confirmed a significant reduction in the expression of HSC niche factors ( Vcam1 Cxcl12 and Scf) following Vcam1 deletion, indicative of reduced niche activity. As expected, Vcam1 deletion in N-Cadherin-Cre ER MSCs, caused significant mobilization of HSCs into the blood (p&amp;lt;0.0001) and BM homing defects (p&amp;lt;0.05), however the number and repopulation capacity of BM HSCs remained unaltered, as seen by BM transplantation experiments. Surprisingly, imaging analysis of whole-mount bone marrow sternum of phenotypic HSCs revealed no differences in HSC niche localization between Vcam1-null and Control mice. Accordingly, ELISA analysis of BM extracellular fluid revealed no differences in overall CXCL12 and SCF levels suggesting that there may be some local or systemic niche compensation at play. Single-cell (sc)RNAseq of pooled BM and compact bone sorted non-hematopoietic stromal cells (DAPI -Lineage -CD45 -Ter119 -CD19 -CD71 -)from Vcam1 N-CadCreERand Control mice further confirmed the downregulation of HSC niche factors in MSCs, and overall remodeling of the BM stromal cell composition following Vcam1 deletion. Interestingly, our scRNAseq analysis revealed increased expression of Cxcl12 and Scf in specific vascular and stromal cell populations, supporting the notion of HSC niche compensation. Overall, these findings demonstrate that MSC-derived Vcam1 is critical for BM MSC survival and their HSC niche function.

Study of the electroosmotic flow of a structured fluid with a new generalized rheological model

The electroosmotic flow of a viscoelastic fluid in a capillary system was investigated analytically. The rheology of the fluid was characterized by a novel generalized exponential model equation. The charge density obeys the Boltzmann distribution, which governs the electrical double-layer field and body force generated by the applied electrical field. Mathematically, this scenario can be modeled by the Poisson-Boltzmann partial differential equation, by assuming that the zeta potential is small, i.e., less than 25 mV (Debye-Hückel approximation). Considering a pulsating electric field, the shear viscosity and the alteration in the volumetric flow were presented as a function of the material parameters through the characteristic dimensionless numbers by using an exponential-type generalized rheological model. Thixotropy, shear thinning, yield stress mechanisms, and weight concentration were analyzed through numerical results. Finally, the flow properties and rheology were predicted using experimental data reported elsewhere for worm-like micellar solution of cetyl trimethyl ammonium tosilate (CTAT). The rheological equation of state proposed in this study describes the alterations in the structure resulting from applied forces (tangential and normal). These forces induced a structural evolution (kinetic model) due to the relaxation processes caused by shear strain. It is important to mention that in electroosmotic flows, complex behavior such as (i) thixotropy, (ii) rheopexy, and (iii) shear banding flow is scarcely explained in terms of the change in the structure of the fluid under flow.Graphical

The neurovascular unit of capillary blood vessels in the rat nervous system. A rapid-Golgi electron microscopy study.

We describe a pericapillary organ in the rat forebrain and cerebellar cortex. It consists of a series of tripartite synapses with synaptic extensions enveloped by astrocytic endfeet that are linked to the capillary wall by synaptic extensions. Reciprocal specializations of the pericyte-capillary blood vessel (CBV) with such specialized synapses suggest a mechanoreceptor role. In Golgi-impregnated and 3D reconstructions of the cerebral cortex and thalamus, a series of TSs appear to be sequentially ordered in a common dendrite, paralleled by synaptic outgrowths termed golf club synaptic extensions (GCE) opposed to a longitudinal crest (LC) from the capillary basal lamina (BL). Our results show that, in the cerebellar cortex, afferent fibers and interneurons display microanatomical structures that strongly suggest an interaction with the capillary wall. Afferent mossy fiber (MF) rosettes and ascending granule cell axons and their dendrites define the pericapillary passage interactions that are entangled by endfeet. The presence of mRNA of the mechanosensitive channel Piezo1 in the MF rosettes, together with the surrounding end-feet and the capillary wall form mechanosensory units. The ubiquity of such units to modulate synaptic transmission is also supported by Piezo1 mRNA expressing pyramidal isocortical and thalamic neurons. This scenario suggests that ascending impulses to the cerebellar and cortical targets are presynaptically modulated by the reciprocal interaction with the mechanosensory pericapillary organ that ultimately modulates the vasomotor response.