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Subarachnoid hemorrhage is a severe condition associated with high mortality and morbidity rates, with aneurysm being one of its primary causes. Currently, there is no effective method to clear the blood present in the subarachnoid space. The objective of this study is to investigate the distribution of red blood cells in anatomical locations following SAH and how the central nervous system spontaneously clears these cells.

The SAH model is induced by endovascular surgery, inserting a fine filament into the internal carotid artery and extending it through the basal artery of the skull base. Two hours later, the skull is collected and undergoes fixation, decalcification, dehydration, and other procedures, ultimately being sliced into coronal sections. Immunofluorescence staining is used to detect key protein indicators to clarify various anatomical structures.
Fluorescence microscopy is employed to image tissues, followed by confocal microscopy for z-stack scanning of the sections, thereby obtaining images with higher clarity.

A stable model of medium severity SAH was established; Both spinal and cranial lymphatic pathways drain RBCs after SAH; Multiple cranial nerve routes were implicated in erythrocyte clearance; The dura mater plays a role in erythrocyte clearance after SAH， Particularly in the double folding regions such as the TS and CS, where RBCs enter potential “Collagen pathways"; Blood may flow through the SAS and subdural space, descending along the spinal axis to the coccygeal region; Notably, RBCs demonstrate the capacity to infiltrate both ganglia and epineurium spaces in cervical, thoracic, and lumbar regions, while their penetration appears limited to epineurium spaces in sacral or lower regions.

The clearance of red blood cells involves the conventional tracer clearance pathways, but these red cells have been found in areas where conventional tracers should not be present, possibly due to elevated intracranial pressure.

Glycocalyx (GCX) is a negatively charged sugar–protein barrier that lines all healthy vascular endothelium, where it contributes to maintain the barrier properties and to transduce intracellular signalling induced by flow. A reduction of GCX thickness and density is associated with cardiovascular disease development and progression. Aging, characterized by increased vascular stiffness, impairs GCX expression. This study aims to disentangle the effects of substrate stiffness and cellular aging to examine their individual and combined influence on GCX expression.

Human umbilical vein endothelial cells were cultured on PDMS substrates with either soft (~0.2kPa) or stiff (~64MPa) mechanical properties. Cellular senescence was induced using a chronic TNFa treatment, resulting in four experimental conditions: young cells on soft, young cells on stiff, senescent cells on soft, and senescent cells on stiff. GCX expression in confluent and mature monolayers was analyzed by western blot, immunofluorescence and RT-qPCR.

Our results indicate that GCX protein expression is influenced by both cell age and substrate stiffness, but age appears to be the dominant factor. Analysis of heparan sulfate levels, a key component of the GCX, revealed a significant reduction in senescent cells compared to younger ones, regardless of whether they were cultured on soft or stiff substrates. While substrate stiffness induced some changes in GCX composition, these effects were less pronounced than those driven by cellular aging. The analysis of GCX-related enzyme expression revealed that both heparan sulfate synthesis enzymes and hyaluronan synthases are expressed at lower levels in cells cultured on stiff substrates compared to those on soft substrates. Hyaluronidases and matrix metalloproteinases are expressed at higher levels in senescent cells compared to young cells, suggesting increased GCX degradation with aging. While there is a trend of slightly higher expression of these enzymes on stiff substrates compared to soft ones, the effect of cell aging is more pronounced than that of substrate stiffness.

Our results suggest aging as the primary driver of GCX breakdown, with substrate stiffness playing a more subtle role in modulating enzyme activity.

Starvation and infection are major threats to all living organisms. Vertebrates rely on a complex network of blood vessels to meet tissue demands for oxygen and nutrients, though this system also facilitates pathogen spread. The mechanisms through which the endothelium balances efficient nutrient delivery with protection against viral infections remain poorly understood.

We generated a mouse model with endothelial-specific deletion of the transmembrane adaptor protein Myct1 (Myct1ecKO) and characterized its phenotype using a combination of metabolic induction assays, whole-mount immunostaining, and single-cell RNA sequencing. To gain mechanistic insights, we defined the endothelial MYCT1 interactome using mass spectrometry and evaluated the significance of selected interactions for MYCT1 function in vitro.

Here, we find that the interaction of the pan-endothelial transmembrane adaptor protein MYCT1 with the viral restriction factor IFITM2/3 is crucial for balancing nutrient transport and antiviral defense. In endothelial cells, constitutively expressed IFITM2/3 are sequestered by MYCT1 restricting their endosomal accumulation. In the absence of MYCT1 or upon interferon exposure, IFITM2/3 accumulate in early endosomes, promote endolysosomal cargo degradation and hyper-activation of mTORC1 signaling in endothelial cells, limiting energy storage in white adipose tissue.

Our results reveal a novel endothelial-specific mechanism balancing energy storage and antiviral defense in the vascular system.

As Europe’s population continues to age, a higher prevalence of chronic conditions arises, hence escalating healthcare costs. Among the systems affected by aging, the lymphatic vasculature plays a crucial role in maintaining fluid balance, immune function and tissue homeostasis. Age-related deterioration of the lymphatic system has been linked to disorders such as lymphedema, chronic inflammation and metabolic imbalances. Despite its significance, lymphatic vascular aging remains poorly understood due to the lack of physiologically relevant human models. Engineering advanced in vitro platforms that accurately replicate lymphatic endothelial aging could provide valuable insights into these processes and drive translational advancements.

To address this gap, we developed a high-throughput platform capable of generating up to 32 human 3D organotypic models. These models are biofabricated using human dermal lymphatic endothelial cells (HDLECs) and dermal fibroblasts (HDF) derived from healthy donor biopsies, embedded within a fibrin hydrogel. The system features mesoscale dimensions (millimeter-scale) and integrates physiologically relevant co-culture conditions with controlled unidirectional flow. The platform also enables automated hydrogel seeding, high-resolution confocal imaging and functional perfusability analysis.

We developed a robust protocol to obtain pure populations of HDLECs and HDF from skin biopsies characterized with a combination of identity markers (PROX1, PDPN, CD45, CD49a, FSP1, NG2). Under optimized culture conditions (VEGF-A + VEGF-C), the self-assembled lymphatic microvascular networks exhibited vessel physiological diameters (10-60 micrometers) and network coverage (15-30%), which closely align with values reported in vivo. Functional perfusability assays using 70kDa-dextran confirmed the successful lumen formation throughout the entire network. We are currently focused on validating lymphatic markers (PROX1, LYVE1, PDPN) within the model while comparing microvascular architecture to human dermal biopsies from donors of different age.

Our 3D lymphatic microvascular model successfully replicates key structural and functional aspects of the human lymphatic system. Moving forward, we aim to elucidate the molecular and functional effects of donor age on our model by incorporating cells retrieved from old (>65 y/o) and young (<35 y/o) donors.

This case report discusses a 44-year-old patient who presented with acute rupture of a splenic artery pseudoaneurysm several weeks after sustaining a blunt abdominal trauma on a mountain bike accident and with a history of bariatric surgery.

The patient was transferred from a primary care institution with hemodynamic instability, diffuse abdominal pain, and significant laboratory abnormalities, six weeks after blunt abdominal trauma sustained in a mountain biking accident. CT imaging confirmed a Grade 3b splenic laceration and a contained rupture of the splenic artery pseudoaneurysm. Urgent angiography and embolization were performed, achieving hemostasis with the placement of six coils.

Post-intervention, the patient developed post-traumatic pancreatitis, which was managed conservatively. He was discharged in stable condition after seven days, with follow-up imaging showing no complications and inflammatory markers normalizing with antibiotic therapy.

This case highlights the importance of diagnostic such as management challenges of SAP in the setting of blunt trauma and with a history of a gastric bypass 2 years ago. Endovascular intervention is a key treatment option, though complex cases require multidisciplinary care and close monitoring for associated complications.

Multiple sclerosis (MS) is considered an autoimmune disease of the central nervous system (CNS). Blood-brain barrier (BBB) breakdown is amongst the earliest pathological hallmarks observed in MS. The mechanisms leading to BBB dysfunction are incompletely understood and are generally thought to be a consequence of the autoimmune neuroinflammatory process in MS. We have challenged this view as we observed that human induced pluripotent stem cell (hiPSC) derived brain microvascular endothelial cells (BMECs) from persons with MS (pwMS) displayed impaired barrier properties and an inflammatory phenotype when compared to their counterparts from healthy controls (HC).

Here we established additional hiPSCs from a total of 6 HC, 2 persons with radiologically isolated syndrome (RIS) - as a preclinical stage of MS - who later developed MS, and 10 persons with MS and differentiated them into BMECs using the extended endothelial cell culture method (EECM). Phenotype and functional properties were characterized by immunostaining, permeability measurements and transendothelial electrical resistance (TEER). Their transcriptional profile was investigated by bulk RNA sequencing (RNAseq).

RIS- and MS-derived EECM-BMECs displayed impaired barrier properties when compared to HC-derived EECM-BMECs. Transcriptional profiling distinguished MS and RIS-derived EECM-BEMCs from those derived from HC. For example, when compared to HC-derived EECM-BMECs, RIS- and MS-derived EECM-BMECs displayed reduced expression levels of CLDN5 which is accompanied by interrupted junctional localization of claudin-5 protein. In addition, we found modulation of the Semaphorin-4D (SEMA4D) signalling pathway in MS-versus HC-derived EECM-BMECs and could show that soluble SEMA4D decreased SEMA4D mRNA expression in EECM-BMECs.

Our observations underscore that intrinsic alterations in brain endothelial cells manifested at the genetic or epigenetic, transcriptional and ultimately phenotypic level cause or contribute to altered BBB function already in pwRIS, which in combination with additional risk factors is crucial for the development of clinical MS.

Our previously published research demonstrated that hematopoietic deficiency of the chemokine-like receptor ChemR23 led to a reduced lesion size in a murine models. However, observations from studies using systemic ChemR23-deficient animals suggest that ChemR23 may have a cell-specific function within the context of atherosclerosis. To explore this hypothesis, we examined the specific role of ChemR23 in vascular cells.

Using a knockout/knock-in reporter mouse model we transplanted bone marrow from Apolipoprotein E-deficient (Apoe-/-) into both Apoe-/- and Apoe-/-ChemR23eGFP/eGFP mice, rendering these mice deficient in ChemR23 in non-hematopoietic (somatic) cells, mice were fed a Western diet (WD) for 6 or 12 weeks. Lesions characteristic and morphology was examined via histological staining, the aorta also underwent bulk RNA sequencing. The functional role of ChemR23 was further examined by studying human aortic SMCs (HASMCs) with a ChemR23 inhibitor α-NETA, or ligand chemerin 9.

Mice, absence in ChemR23 in somatic cells, fed a Western diet for either 6 or 12 weeks led to significantly larger atherosclerotic lesions and increased lipid accumulation. Histological analysis revealed that, loss of ChemR23 resulted in enhanced migration of smooth muscle cells (SMCs) into the plaque, as well as an increase in the formation of SMC-derived foam cells (SMFCs). Bulk RNA sequencing showed that without vascular ChemR23, atherosclerotic pathways and genes for synthetic, athero-progressive smooth muscle cell (SMC) phenotypes are upregulated. In vitro experiments with HASMCs treated with α-NETA, indicated increased cholesterol uptake and reduced efflux, implying that blocking ChemR23 favors SMC-derived foam cell (SMFC) formation. α-NETA also boosted the expression of athero-progressive genes like KLF4, CD36, and MAC2 in HASMCs and enhanced their migration, more so than when treated with chemerin 9, a ChemR23 activator, after INF-γ pre-treatment.

In a therapeutic study, ApoE-deficient mice received α-NETA, chemerin 9, or a vehicle via osmotic pump during a 4-week Western diet. Both treatments reduced lesion sizes but showed unique plaque traits and mechanisms, indicating the need for more research. Our results underscore ChemR23's key role in vascular smooth muscle cell phenotypic regulation, marking it as a promising target for atherosclerosis treatment.

Primary endothelial cells from adult donors are an essential tool for modeling and studying vascular aging and age-related diseases (ARDs). However, their limited proliferative capacity due to the Hayflick limit represents a major bottleneck for applications requiring high cell yields and extensive in vitro testing conditions. This project aims to overcome this limitation by establishing a transient immortalization system to expand Human Dermal Blood Endothelial Cells (HDBECs) from elderly donors, enabling subsequent reversion to a mortal state while preserving key aging markers.

HDBECs were isolated from adult skin biopsies and sorted by FACS. Cells were transduced with a lentiviral vector carrying a FLEX-flanked cassette encoding SV40 Large T antigen and iCas9, both under the control of the CMV promoter. Following puromycin selection, proliferation was assessed over serial passages. Immortalization was reversed using Cre-mediated recombination, and AP20187 treatment was used to eliminate not successfully re-mortalized cells. To assess the efficiency and robustness of this strategy, endothelial identity, expression of aging markers, and cell cycle profile were monitored throughout the process.

Immortalized HDBECs initially showed enhanced proliferation and a significant accumulation in the G2/M phase (47.8%±4.9% vs 5.7%±4.9% in control cells), indicating a shift in cell cycle dynamics. Subsequently, Cre-mediated recombination enabled successful reversion of the immortalized state, and AP20187 treatment effectively eliminated residual cells that had escaped the re-mortalization process. Following this reversion, HDBECs re-entered the G1 phase and consistently preserved their endothelial identity (ERG+ nuclei: 97.7%±2.3%). Importantly, aging-related features were preserved: γ-H2AX phosphorylation remained elevated (9.1%±2.0%), while FosB expression was stable (1.09±1.28 vs 1.14±1.12) and Klotho expression was restored to levels comparable to untransduced cells (0.21±0.12 vs 0.89±0.30).

This reversible immortalization strategy enables scalable HDBEC expansion without loss of endothelial identity or aging features. It supports the development of physiologically relevant in vitro models for vascular aging and ARDs research, and is currently being applied to the biofabrication of microvascular networks using 3D culture systems developed by our group.