Exploring the Molecular and Developmental Dynamics of Endothelial Cell Differentiation.

The development and differentiation of endothelial cells (ECs) are fundamental processes with significant implications for both health and disease. ECs, which are found in all organs and blood vessels, play a crucial role in facilitating nutrient and waste exchange and maintaining proper vessel function. Understanding the intricate signaling pathways involved in EC development holds great promise for enhancing vascularization, tissue engineering, and vascular regeneration. Hematopoietic stem cells originating from hemogenic ECs, give rise to diverse immune cell populations, and the interaction between ECs and immune cells is vital for maintaining vascular integrity and regulating immune responses. Dysregulation of vascular development pathways can lead to various diseases, including cancer, where tumor-specific ECs promote tumor growth through angiogenesis. Recent advancements in single-cell genomics and in vivo genetic labeling have shed light on EC development, plasticity, and heterogeneity, uncovering tissue-specific gene expression and crucial signaling pathways. This review explores the potential of ECs in various applications, presenting novel opportunities for advancing vascular medicine and treatment strategies.

Amyloid beta peptides (Aß) from Alzheimer's disease neuronal secretome induce endothelial activation in a human cerebral microvessel model.

In Alzheimer's disease (AD), secretion and deposition of amyloid beta peptides (Aß) have been associated with blood-brain barrier dysfunction. However, the role of Aß in endothelial cell (EC) dysfunction remains elusive. Here we investigated AD mediated EC activation by studying the effect of Aß secreted from human induced pluripotent stem cell-derived cortical neurons (hiPSC-CN) harboring a familial AD mutation (Swe+/+) on human brain microvascular endothelial cells (HBMECs) in 2D and 3D perfusable microvessels. We demonstrated that increased Aß levels in Swe+/+ conditioned media (CM) led to stress fiber formation and upregulation of genes associated with endothelial inflammation and immune-adhesion. Perfusion of Aß-rich Swe+/+ CM induced acute formation of von Willebrand factor (VWF) fibers in the vessel lumen, which was attenuated by reducing Aß levels in CM. Our findings suggest that Aß peptides can trigger rapid inflammatory and thrombogenic responses within cerebral microvessels, which may exacerbate AD pathology.

Cyclosporine Induces Fenestra-Associated Injury in Human Renal Microvessels In Vitro.

The use of cyclosporine A (CsA) in transplantation is frequently associated with nephrotoxicity, characterized by renal vascular injury, thrombotic microangiopathy, and striped interstitial fibrosis. Here, using human kidney-specific microvascular endothelial cells (HKMECs), we showed that CsA inhibited NFAT1 activation and impaired VEGF signaling in these ECs in a dose- and time-dependent manner. Integrated genome regulatory analyses identified key distinctions in the landscapes of HKMECs compared to human umbilical vein endothelial cells, particularly around genes related to the formation and maintenance of fenestrae. Using a bioengineered flow-directed 3D kidney microphysiological system, we revealed that CsA-induced kidney microvascular injury was associated with fenestrae and cell adhesion impairment, membrane swelling, and erythrocyte adhesion and extravasation into the interstitial space. Our data provide novel insights into kidney-specific molecular and structural mechanisms of CsA-induced microvascular injury. Our results also suggest VEGF-related pathways as potential targets for therapy during CsA treatment and emphasize the importance of leveraging species and organ-specific cells to better reflect human pathophysiology and the response to injury.

Organ-on-a-chip systems for vascular biology.

Organ-on-a-chip (OOC) platforms involve the miniaturization of cell culture systems and enable a variety of novel experimental approaches. These range from modeling the independent effects of biophysical forces on cells to screening novel drugs in multi-organ microphysiological systems, all within microscale devices. As in living systems, the incorporation of vascular structure is a key feature common to almost all organ-on-a-chip systems. In this review we highlight recent advances in organ-on-a-chip technologies with a focus on the vasculature. We first present the developmental process of the blood vessels through which vascular cells assemble into networks and remodel to form complex vascular beds under flow. We then review self-assembled vascular models and flow systems for the study of vascular development and biology as well as pre-patterned vascular models for the generation of perfusable microvessels for modeling vascular and tissue function. We finally conclude with a perspective on developing future OOC approaches for studying different aspects of vascular biology. We highlight the fit for purpose selection of OOC models towards either simple but powerful testbeds for therapeutic development, or complex vasculature to accurately replicate human physiology for specific disease modeling and tissue regeneration.

3D bioprinting of mechanically tuned bioinks derived from cardiac decellularized extracellular matrix.

3D bioprinting is a powerful technique for engineering tissues used to study cell behavior and tissue properties in vitro. With the right formulation and printing parameters, bioinks can provide native biological and mechanical cues while allowing for versatile 3D structures that recapitulate tissue-level organization. Bio-based materials that support cellular adhesion, differentiation, and proliferation - including gelatin, collagen, hyaluronic acid, and alginate - have been successfully used as bioinks. In particular, decellularized extracellular matrix (dECM) has become a promising material with the unique ability to maintain both biochemical and topographical micro-environments of native tissues. However, dECM has shown technical limitations for 3D printing (3DP) applications posed by its intrinsically low mechanical stability. Herein, we report hydrogel bioinks composed of partially digested, porcine cardiac decellularized extracellular matrix (cdECM), Laponite-XLG nanoclay, and poly(ethylene glycol)-diacrylate (PEG-DA). The Laponite facilitated extrusion-based 3DP, while PEG-DA enabled photo-polymerization after printing. Improving upon previously reported bioinks derived from dECM, our bioinks combine extrudability, shape fidelity, rapid cross-linking, and cytocompatibility in a single formulation (> 97% viability of encapsulated human cardiac fibroblasts and > 94% viability of human induced pluripotent stem cell derived cardiomyocytes after 7 days). The compressive modulus of the cured hydrogel bioinks was tunable from 13.4-89 kPa by changing the concentration of PEG-DA in the bioink formulation. Importantly, this span of mechanical stiffness encompasses ranges of tissue stiffness from healthy (compressive modulus ~5-15 kPa) to fibrotic (compressive modulus ~30-100 kPa) cardiac tissue states. The printed constructs demonstrated shape fidelity, adaptability to different printing conditions, and high cell viability following extrusion and photo-polymerization, highlighting the potential for applications in modeling both healthy and fibrotic cardiac tissue.

Validation of the Good Outcome Following Attempted Resuscitation (GO-FAR) score in an East Asian population.

AIM: The Good Outcome Following Attempted Resuscitation (GO-FAR) score is useful for identifying patients post-arrest with very poor neurologic outcomes and may thus be utilized when counseling family members on do-not-attempt-resuscitation (DNAR) order. We validated the GO-FAR score for neurologically intact survival in patients with in-hospital cardiac arrest (IHCA) in an East Asian country in which DNAR order not common. METHODS: Retrospective study about patients who experienced IHCA from 2013 to 2017 with a primary outcome of neurologically intact survival, defined as a CPC score 1 or 2 at discharge. GO-FAR score categorizes the patients into 4 groups: a very low (<1%), low (1%-3%), average (>3%-15%), or higher than average (>15%) likelihood of neurologically intact survival. RESULTS: Of the 1011 included patients, the rates of survival discharge and neurologically intact survival at discharge were 25.4% and 16.0%, respectively. The area under the receiver operating characteristics curve of GO-FAR score for good neurological outcome was 0.81 (95% CI, 0.78-0.84). Patients with low or very low probability of survival had a likelihood of 0.9% (95% CI, 0.0-2.0), but for those under 40 years old, it was increased to 4.2% (95% CI, 0.0-12.2). Patients with average or above-average probabilities had likelihoods of of 18.5% (95% CI, 15.3-21.6) and 50.5% (95% CI, 40.6-60.5), respectively. CONCLUSIONS: The GO-FAR score well-predicted the neurologically intact survival of East Asian patients with IHCA. This tool may be used as part of a shared decision regarding DNAR orders.

Fate-mapping post-hypoxic tumor cells reveals a ROS-resistant phenotype that promotes metastasis.

Hypoxia is known to be detrimental in cancer and contributes to its development. In this work, we present an approach to fate-map hypoxic cells in vivo in order to determine their cellular response to physiological O2 gradients as well as to quantify their contribution to metastatic spread. We demonstrate the ability of the system to fate-map hypoxic cells in 2D, and in 3D spheroids and organoids. We identify distinct gene expression patterns in cells that experienced intratumoral hypoxia in vivo compared to cells exposed to hypoxia in vitro. The intratumoral hypoxia gene-signature is a better prognostic indicator for distant metastasis-free survival. Post-hypoxic tumor cells have an ROS-resistant phenotype that provides a survival advantage in the bloodstream and promotes their ability to establish overt metastasis. Post-hypoxic cells retain an increase in the expression of a subset of hypoxia-inducible genes at the metastatic site, suggesting the possibility of a 'hypoxic memory.'

Association Between Time to Defibrillation and Neurologic Outcome in Patients With In-Hospital Cardiac Arrest.

BACKGROUND: The influence of time to defibrillation in patients with shockable in-hospital cardiac arrest (IHCA) has not been fully assessed. This study investigated the association between time to defibrillation and neurologic outcome in shockable IHCA survivors. MATERIALS AND METHODS: A 7-year retrospective cohort study was conducted using a prospectively collected registry of adult IHCA patients. Patients whose first documented rhythm was pulseless ventricular tachycardia or ventricular fibrillation and who received defibrillation within 5 minutes were included. RESULTS: Among 1,683 IHCA patients, 261 patients were included. At 28 days, a good neurologic outcome (Cerebral Performance Category score 1 or 2) according to time to defibrillation was seen in 49.0%, 21.1%, 13.4% and 16.5% of patients treated at <2 minutes (n = 128), 2-3 minutes (n = 55), 3-4 minutes (n = 35) and 4-5 minutes (n = 43) after IHCA, respectively. After adjusting for clinical characteristics, a graded inverse association was found after 3 minutes. CONCLUSIONS: A graded inverse association between time to defibrillation and neurologic outcome was observed beyond 3 minutes following cardiac arrest. A target time to defibrillation of <3 minutes may be a practical target goal in resource-limited hospitals.

Unraveling the Mechanobiology of the Immune System.

Cells respond and actively adapt to environmental cues in the form of mechanical stimuli. This extends to immune cells and their critical role in the maintenance of tissue homeostasis. Multiple recent studies have begun illuminating underlying mechanisms of mechanosensation in modulating immune cell phenotypes. Since the extracellular microenvironment is critical to modify cellular physiology that ultimately determines the functionality of the cell, understanding the interactions between immune cells and their microenvironment is necessary. This review focuses on mechanoregulation of immune responses mediated by macrophages, dendritic cells, and T cells, in the context of modern mechanobiology.

Nictitating membrane fixation improves stability of the contact lens on the animal corneal surface.

We evaluated the feasibility and safety of nictitating membrane fixation to address reduced contact lens stability by the nictitating membrane in a rabbit model. Under general anesthesia, twelve animals received a horizontal mattress suture between the nictitating membrane and the upper eyelid of one eye. To assess the effects of this technique and secondary side effects, contact lens stability test, Schirmer tear test, tear break-up time measurement, eye tissue pathology and morphology were evaluated. Contact lens stability was increased after nictitating membrane fixation. The percentage of contact lens retention in the nictitating membrane fixed rabbit after 4 hours was 90% whereas that in the untreated rabbit was 42.5%. In addition, there were no significant differences in tear quantity and quality between the fixed and untreated eyes. Furthermore, no remarkable pathological lesions were found in gross observation during the 1-month time period or the following pathological examination. In this study, we demonstrated that nictitating membrane fixation increases contact lens stability without specific side effects using a rabbit model. This minimally invasive procedure could be useful when designing animal models for testing new contact lenses and has potential to apply to other biomaterial research on the ocular surface.

Effects of a simulated emergency airway management education program on the self-efficacy and clinical performance of intensive care unit nurses.

AIM: To examine the effects of a simulated emergency airway management education program on the self-efficacy and clinical performance among nurses in intensive care units. METHODS: A one-group, pre- and post-test design was used. Thirty-five nurses who were working in adult intensive care units participated in this study. The simulation education program included lectures, skill demonstration, skill training, team-based practice, and debriefing. Self-efficacy and clinical performance questionnaires were completed before the program and 1 week after its completion. The data were analyzed by using descriptive statistics and the paired t-test to compare the mean differences between the pre-test and post-test. The scores before and after education were compared. RESULTS: After education, there was a significant improvement in the nurses' self-efficacy and clinical performance in emergency airway management situations. CONCLUSION: Simulation education effectively improved the self-efficacy and clinical performance of the nurses who were working in intensive care units. Based on the program for clinical nurses within a hospital, it will provide information that might advance clinical nursing education.

Modified Early Warning Score Changes Prior to Cardiac Arrest in General Wards.

PURPOSE: The frequency, extent, time frame, and implications of changes to the modified early warning score (MEWS) in the 24 hours prior to cardiac arrest are not known. Our aim was to determine the prevalence and trends of the MEWS prior to in-hospital cardiac arrest (IHCA) on a ward, and to evaluate the association between changes in the MEWS and in-hospital mortality. METHODS: A total of 501 consecutive adult IHCA patients who were monitored and resuscitated by a medical emergency team on the ward were enrolled in the study between March 2009 and February 2013. The MEWS was calculated at 24 hours (MEWS24), 16 hours (MEWS16), and 8 hours (MEWS8) prior to cardiac arrest. RESULTS: Out of 380 patients, 268 (70.5%) had a return of spontaneous circulation. The survival rate to hospital discharge was 25.8%. When the MEWS was divided into three risk groups (low: ≤2, intermediate: 3-4, high: ≥5), the distribution of the low-risk MEWS group decreased at each time point before cardiac arrest. However, even 8 hours prior to cardiac arrest, 45.3% of patients were still in the low MEWS group. The MEWS was associated with in-hospital mortality at each time point. However, increasing MEWS value from MEWS24 to MEWS8 was not associated with in-hospital mortality [OR 1.24 (0.77-1.97), p = 0.38]. CONCLUSIONS: About half of patients were still in low MEWS group 8 hours prior to cardiac arrest and an increasing MEWS only occurred in 46.8% of patients, suggesting that monitoring the MEWS alone is not enough to predict cardiac arrest.