Biocompatibility Testing of UV-Curable Polydimethylsiloxane for Human Umbilical Vein Endothelial Cell Culture on-a-Chip.

Polydimethylsiloxane (PDMS) is extensively used to fabricate biocompatible microfluidic systems due to its favorable properties for cell culture. Recently, ultraviolet-curable PDMS (UV-PDMS) has shown potential for enhancing manufacturing processes and final optical quality while retaining the benefits of traditional thermally cured PDMS. This study investigates the biocompatibility of UV-PDMS under static and flow conditions using human umbilical vein endothelial cells (HUVECs). UV-PDMS samples were treated with oxygen plasma and boiling deionized water to assess potential improvements in cell behavior compared with untreated samples. We evaluated HUVECs adhesion, growth, morphology, and viability in static cultures and microchannels fabricated with UV-PDMS to test their resistance to flow conditions. Our results confirmed the biocompatibility of UV-PDMS for HUVECs culture. Moreover, plasma-oxygen-treated UV-PDMS substrates exhibited superior cell growth and adhesion compared to untreated UV-PDMS. This enhancement enabled HUVECs to maintain their morphology and viability under flow conditions in UV-PDMS microchannels. Additionally, UV-PDMS demonstrated improved optical quality and more efficient handling and processing, characterized by shorter curing times and simplified procedures utilizing UV light compared to traditional PDMS.

Edoxaban treatment in a post-infarction experimental model.

BACKGROUND: The sequelae of myocardial infarction (MI) require specific pharmacological therapy to minimise the post-MI remodelling, which in many cases evolves into cardiovascular complications. The aim of this study was to analyse the effect of edoxaban, an oral anticoagulant, on cardiac recovery in a rat model of permanent coronary artery ligation. METHODS: An experimental method to assess the post-MI remodelling in rats for 4 weeks, based on cardiac magnetic resonance imaging (MRI) and final histological analysis of the hearts was performed. The influence of daily oral treatment with edoxaban (20 mg/kg/day) for 28 days post-MI was analysed in comparison to vehicle. RESULTS: In our model, edoxaban was shown to be safe and bleeding was observed in 1 of 10 animals. General physical recovery of the treated animals was shown by higher body weight recovery compared with non-treated animals (38.6 ± 2.9 vs. 29.9 ± 3.1 g, respectively, after 28 days). There was not a pronounced effect of edoxaban in post-MI cardiac remodelling, but mitigated fibrosis was observed by the reduced expression of vascular endothelial growth factor and tumour growth factor ß1 in the peri-infarct zone. CONCLUSIONS: Our analysis provided the experimental basis to support the feasibility of MRI to study cardiac function and characterise myocardial scarring in a rat model. Overall data suggested the safety of edoxaban in the model, and compared to placebo, it showed a better post-MI recovery, probably by reducing fibrosis of the heart. Further research on mid-term cardiac recovery with edoxaban after MI is justified.

Role of Soluble ST2 Biomarker in Predicting Recurrence of Atrial Fibrillation after Electrical Cardioversion or Pulmonary Vein Isolation.

This study aims to determine the predictive value of the soluble suppression of tumorigenicity 2 (sST2) biomarker in atrial fibrillation (AF) recurrence. This prospective, observational study included patients with AF referred for electrical cardioversion (ECV) or pulmonary vein isolation (PVI) procedures. Baseline characteristics were collected, and sST2 was determined at baseline and at 3 and 6 months of follow-up. sST2 was determined at baseline in a matched control group. Left atrial voltage mapping was performed in patients undergoing PVI. The sST2 maximal predictive capacity of AF recurrence was at the 3-month FU in the cohort of patients undergoing ECV with respect to 6-month AF recurrence with an AUC of 0.669, a cut-off point of 15,511 pg/mL, a sensitivity of 60.97%, and a specificity of 69.81%. The ROC curve of the sST2 biomarker at baseline and 3 months in the cohort of patients undergoing PVI showed AUCs of 0.539 and 0.490, respectively. The logistic regression model identified the rhythm (AF) and the sST2 biomarker at 3 months as independent factors for recurrence at 6 months in the ECV cohort. In the logistic regression model, sST2 was not an independent factor for recurrence at 6 months of follow-up in the PVI cohort. In patients who underwent ECV, sST2 values at 3 months may provide utility to predict AF recurrence at 6 months of follow-up. In patients who underwent PVI, sST2 had no value in predicting AF recurrence at 6 months of follow-up.

Vessel-on-a-Chip: A Powerful Tool for Investigating Endothelial COVID-19 Fingerprints.

Coronavirus disease (COVID-19) causes various vascular and blood-related reactions, including exacerbated responses. The role of endothelial cells in this acute response is remarkable and may remain important beyond the acute phase. As we move into a post-COVID-19 era (where most people have been or will be infected by the SARS-CoV-2 virus), it is crucial to define the vascular consequences of COVID-19, including the long-term effects on the cardiovascular system. Research is needed to determine whether chronic endothelial dysfunction following COVID-19 could lead to an increased risk of cardiovascular and thrombotic events. Endothelial dysfunction could also serve as a diagnostic and therapeutic target for post-COVID-19. This review covers these topics and examines the potential of emerging vessel-on-a-chip technology to address these needs. Vessel-on-a-chip would allow for the study of COVID-19 pathophysiology in endothelial cells, including the analysis of SARS-CoV-2 interactions with endothelial function, leukocyte recruitment, and platelet activation. "Personalization" could be implemented in the models through induced pluripotent stem cells, patient-specific characteristics, or genetic modified cells. Adaptation for massive testing under standardized protocols is now possible, so the chips could be incorporated for the personalized follow-up of the disease or its sequalae (long COVID) and for the research of new drugs against COVID-19.

Relaxin-2 plasma levels in atrial fibrillation are linked to inflammation and oxidative stress markers.

Relaxin-2 exerts many favourable cardiovascular effects in pathological circumstances such as atrial fibrillation (AF) and heart failure, but the mechanisms underlying its actions are not completely understood. Since inflammation and fibrosis are pivotal processes in the pathogenesis of AF, our aim was to study the relationship between relaxin-2 plasma levels in left atrium (LA) and peripheral vein with molecules implicated in fibrosis, inflammation and oxidative stress in AF patients, and to evaluate the anti-fibrotic ability of relaxin-2 in normal human atrial cardiac fibroblasts (NHCF-A). Peripheral vein relaxin-2 plasma levels were higher than LA relaxin-2 plasma levels in men while, in women, peripheral vein relaxin-2 levels were increased compared to men. AF patients with higher levels of relaxin-2 exhibited a reduction in H2O2 plasma levels and in mRNA levels of alpha-defensin 3 (DEFA3) and IL-6 in leucocytes from LA plasma. Relaxin-2-in-vitro treatment inhibited NHCF-A migration and decreased mRNA and protein levels of the pro-fibrotic molecule transforming growth factor-ß1 (TGF-ß1). Our results support an association between relaxin-2 and molecules involved in fibrosis, inflammation and oxidative stress in AF patients, and reinforce an anti-fibrotic protective role of this hormone in NHCF-A; strengthening the relevance of relaxin-2 in AF physiopathology, diagnosis and treatment.

The Role of Fatty Acid-Binding Protein 4 in the Characterization of Atrial Fibrillation and the Prediction of Outcomes after Catheter Ablation.

Aims: The utility of biomarkers in characterizing atrial cardiomyopathy is unclear. We aim to test the ability of biomarkers of fibrosis (galectin-3 (Gal-3)) and adiposity (fatty acid-binding protein 4 (FABP4) and leptin) to predict: (1) the presence of low-voltage areas (LVA) in the electroanatomic voltage mapping; and (2) the recurrence of atrial fibrillation (AF) after pulmonary vein isolation (PVI). Methods: Patients referred for PVI were enrolled. Areas of bipolar voltage < 0.5 mV were considered as LVA. An aggregate score incorporating AF pattern (paroxysmal, persistent and long-standing persistent) and peripheral levels of FABP4 (>20 ng/mL) was developed. Results: 299 patients were included. AF was paroxysmal in 100 (33%), persistent in 130 (43%) and long-standing persistent in 69 (23%). Multivariable analysis revealed age, left atrium area, and the proposed score as independent predictors of LVA. During a mean follow-up period of 972 ± 451 days, freedom from AF recurrence was 63%. The score incorporating AF pattern and FABP4 levels accurately predicted freedom from AF recurrence, stratifying risk into ranges from 28% (score of 1) to 68% (score of 3). Cox regression models identified the score including AF pattern + FABP4 as the best model for AF recurrence (hazard ratio 2.32; 95% CI, 1.19 to 4.5; p = 0.014). Conclusions: Traditional clinical classification of atrial cardiomyopathy may be improved by markers of adiposity (FABP4). The combination allows better prediction of the presence of LVA and AF recurrence post-PVI. Gal-3 provided no added predictive value.

Impact of Enhanced Phagocytosis of Glycated Erythrocytes on Human Endothelial Cell Functions.

Diabetes is associated with a high mortality rate due to vascular complications. Chronic hyperglycemia in diabetes leads to enhanced oxidative stress and glycation. Here, we explored the impact of glycation on human erythrocyte characteristics and capacity to affect endothelial cell function following erythrophagocytosis. Native and glucose-mediated glycated erythrocytes were prepared and characterized in terms of structural and deformability modifications. Erythrocyte preparations were tested for their binding and phagocytosis capacity as well as the potential functional consequences on human endothelial cell lines and primary cultures. Oxidative modifications were found to be enhanced in glycated erythrocytes after determination of their deformability, advanced glycation end-product content and eryptosis. Erythrophagocytosis by endothelial cells was significantly increased when incubated in the presence of glycated erythrocytes. In addition, higher iron accumulation, oxidative stress and impaired endothelial cell permeability were evidenced in cells previously incubated with glycated erythrocytes. When cultured under flow conditions, cellular integrity was disrupted by glycated erythrocytes at microvessel bifurcations, areas particularly prone to vascular complications. This study provides important new data on the impact of glycation on the structure of erythrocytes and their ability to alter endothelial cell function. Increased erythrophagocytosis may have a deleterious impact on endothelial cell function with adverse consequences on diabetic vascular complications.

Minimal invasive fluorescence methods to quantify advanced glycation end products (AGEs) in skin and plasma of humans.

Advanced glycation end products (AGEs) are non-enzymatic modifications of proteins and lipids, which are spontaneously produced in the body in relation with several human diseases. Their relevance on protein functions alteration, either structural or enzymatic is under study, but their value as biomarkers or predictors of disease progression and clinical outcomes is unquestionable. The heterogeneity and amplitude of these modifications make their analysis difficult, although, different methods have been developed for specific AGEs based on colorimetric reactions, immunoassays or chromatography. However, for a massive application on human population, methods based on the autofluorescence of some AGEs stand out. Several qualities of these methods such as label-free measurement, rapidity, cost-effectiveness, and minimal invasiveness make them very useful for periodic measurements in critically ill patients and for the analysis of large populations. Here we explain the rationale of these methods, and we present a step-by-step protocol and the equipment requirements to carry out the estimation of AGE content in skin and plasma. AGE plasma content and skin accumulation are temporally related, so AGE plasmatic levels are a possible predictor of skin AGE content. On the other hand, AGE skin accumulation is a surrogate or an indicator of past AGE levels in plasma and in the rest of the body. AGE levels or their variations have shown to be related with prognosis of several diseases, so they can be used as predictor biomarkers for clinicians.

Haemodynamic-dependent arrest of circulating tumour cells at large blood vessel bifurcations as new model for metastasis.

Homing of circulating tumour cells (CTC) at distant sites represents a critical event in metastasis dissemination. In addition to physical entrapment, probably responsible of the majority of the homing events, the vascular system provides with geometrical factors that govern the flow biomechanics and impact on the fate of the CTC. Here we mathematically explored the distribution of velocities and the corresponding streamlines at the bifurcations of large blood vessel and characterized an area of low-velocity at the carina of bifurcation that favours the residence of CTC. In addition to this fluid physics effect, the adhesive capabilities of the CTC provide with a biological competitive advantage resulting in a marginal but systematic arrest as evidenced by dynamic in vitro recirculation in Y-microchannels and by perfusion in in vivo mice models. Our results also demonstrate that viscosity, as a main determinant of the Reynolds number that define flow biomechanics, may be modulated to limit or impair CTC accumulation at the bifurcation of blood vessels, in agreement with the apparent positive effect observed in the clinical setting by anticoagulants in advanced oncology disease.

Soluble angiotensin-converting enzyme levels in heart failure or acute coronary syndrome: revisiting its modulation and prognosis value.

The main objective was to compare the meaning of soluble angiotensin-converting enzyme-2 (sACE2) plasma levels modulation on the prognosis of two cohorts of heart failure (HF) and acute coronary syndrome (ACS). We conducted an observational clinical study where sACE2 was measured in two cohorts of HF or ACS (102 patients each), matched by age and gender. The primary endpoint (cardiac death) and the secondary endpoints (non-fatal myocardial infarction or HF readmission) were registered during a 5-year follow-up period. Association with pharmacotherapy was studied, and the effects of cardiovascular drugs on ACE isoforms expression were analysed in human umbilical vein endothelial cells (HUVEC) in vitro. The levels of sACE2 were significantly higher in the HF than ACS cohort. sACE2 was inversely related with the leukocytes number and directly with urea levels. In the ACS cohort, sACE2 was associated with age and glycaemic parameters, but in the HF cohort, the association was with N-terminal pro-B-type natriuretic peptide. The levels of sACE2 were related to long-term prognosis and confirmed as a non-independent predictor in the HF cohort. Soluble ACE2 was higher in patients treated with angiotensin receptors blockers and ß-blockers, accordingly with losartan and metoprolol upregulation of ACE1 and ACE2 in HUVECs. Plasma levels of sACE2 were higher in HF than in ACS, independently of age and gender, and were related to long-term cardiac death in the HF cohort. Losartan and metoprolol, but not enalapril, upregulated ACE expression in endothelial cells, accordingly with higher levels of sACE2 in patients using these drugs.

Microfluidic devices manufacturing with a stereolithographic printer for biological applications.

Stereolithographic printers have revolutionized many manufacturing processes with their capacity to easily produce highly detailed structures. In the field of microfluidics, this technique avoids the use of complex steps and equipment of the conventional technologies. The potential of low force stereolithography technology is analysed for the first time using a Form 3B printer and seven printing resins through the fabrication of microchannels and pillars. Manufacturing performance of internal and superficial channels and pillars is studied for the seven printing resins in different configurations. A complete characterization of printed structures is carried out by optical, confocal and SEM microscopy, and EDX analysis. Internal channels with unobstructed lumen are obtained for diameters and angles greater than 500 µm and 60°, respectively. Outward and inward superficial channels in the range of hundreds of microns can be fabricated with an accurate profile, printing them with a perpendicular orientation respect to the base, allowing a proper uncured resin evacuation. Outward channels are replicated by soft lithography using polydimethylsiloxane. Clear, Model and Tough resins show a good behaviour to be used as master, but Amber and Dental resins present a poor topology transference from the master to the replica. According to the needs of devices used for biological and biomedical research, transparency as well as superficial biocompatibility of some resins is evaluated. Human umbilical vein endothelial cells (HUVEC) adhesion is confirmed on Amber, Dental and Clear resins, but these cells were only able to grow and progress as a cell culture over the Amber resin. Therefore, Amber showed an adequate biocompatibility, in terms of cell adhesion and growth for HUVEC.

Estimating COVID-19 cases and outbreaks on-stream through phone calls.

One of the main problems in controlling COVID-19 epidemic spread is the delay in confirming cases. Having information on changes in the epidemic evolution or outbreaks rise before laboratory-confirmation is crucial in decision making for Public Health policies. We present an algorithm to estimate on-stream the number of COVID-19 cases using the data from telephone calls to a COVID-line. By modelling the calls as background (proportional to population) plus signal (proportional to infected), we fit the calls in Province of Buenos Aires (Argentina) with coefficient of determination R 2 > 0.85. This result allows us to estimate the number of cases given the number of calls from a specific district, days before the laboratory results are available. We validate the algorithm with real data. We show how to use the algorithm to track on-stream the epidemic, and present the Early Outbreak Alarm to detect outbreaks in advance of laboratory results. One key point in the developed algorithm is a detailed track of the uncertainties in the estimations, since the alarm uses the significance of the observables as a main indicator to detect an anomaly. We present the details of the explicit example in Villa Azul (Quilmes) where this tool resulted crucial to control an outbreak on time. The presented tools have been designed in urgency with the available data at the time of the development, and therefore have their limitations which we describe and discuss. We consider possible improvements on the tools, many of which are currently under development.

Galectin-3 and soluble RAGE as new biomarkers of post-infarction cardiac remodeling.

Post-infarction remodeling is a clinical problem with no curative treatment. Our objective was to search for new biomarkers of cardiac remodeling that have clinical value after ST-segment elevation myocardial infarction (STEMI). This pilot study enrolled 67 consecutive patients with de novo STEMI who underwent revascularization by primary angioplasty. Echocardiography studies of cardiac function were completed during the first 48 h post-STEMI and after 6 months of follow-up. Galectin-3 and soluble receptor for advanced glycation end products (sRAGE) were tested in the peripheral venous blood during the 24 h post-infarction. Cardiac remodeling was defined as changes ≥ 15% in the left ventricular end-systolic volume (LVESV) or > 10% in the left atrial area (LAA). An inverse association was found between galectin-3 (rs = - 0.296; p < 0.001) and sRAGE (rs = - 0.327; p < 0.001) levels and the basal left ventricle ejection fraction (LVEF). However, only galectin-3 was directly associated with the increase in LVESV (rs = 0.389; p = 0.007) and LVEDV (rs = 0.314; p = 0.031) during the follow-up. sRAGE was inversely related to the change in LAA (rs = - 0.320; p = 0.032). These data are consistent with galectin-3, but not sRAGE levels, as a predictor of left ventricle remodeling (OR 1.036, 95% CI 1.002-1.071; p = 0.039). Galectin-3 and sRAGE levels that were measured during hospitalization are inversely related to basal LVEF after a STEMI. Galectin-3 levels are a predictor of adverse post-STEMI LV remodeling, whereas sRAGE levels exhibited an inverse relationship with left atrial remodeling. KEY MESSAGES: Post-infarction remodeling is a clinical problem with no curative treatment. New biomarkers for remodeling after acute myocardial infarction were explored. Early post-STEMI galectin-3 and soluble RAGE are inversely related with left ventricle function. Galectin-3 levels were predictors of adverse post-STEMI left ventricle remodeling. Soluble RAGE levels were associated with left atrial remodeling.

Higher ACE2 expression levels in epicardial cells than subcutaneous stromal cells from patients with cardiovascular disease: Diabetes and obesity as possible enhancer.

AIMS: Obesity, diabetes and cardiovascular disease are associated with COVID-19 risk and severity. Because epicardial adipose tissue (EAT) expresses ACE2, we wanted to identify the main factors associated with ACE2 levels and its cleavage enzyme, ADAM17, in epicardial fat. MATERIALS AND METHODS: Epicardial and subcutaneous fat biopsies were obtained from 43 patients who underwent open-heart surgery. From 36 patients, biopsies were used for RNA expression analysis by real-time PCR of ACE1, ACE2 and ADAM17. From 8 patients, stromal vascular cells were submitted to adipogenesis or used for studying the treatment effects on gene expression levels. Soluble ACE2 was determined in supernatants by ELISA. RESULTS: Epicardial fat biopsies expressed higher levels of ACE2 (1.53 [1.49-1.61] vs 1.51 [1.47-1.56] a.u., P < .05) and lower ADAM17 than subcutaneous fat (1.67 [1.65-1.70] vs 1.70 [1.66-1.74] a.u., P < .001). Both genes were increased in epicardial fat from patients with type 2 diabetes mellitus (T2DM) (1.62 [1.50-2.28] vs 1.52 [1.49-1.55] a.u., P = .05 for ACE2 and 1.68 [1.66-1.78] vs 1.66 [1.63-1.69] a.u., P < .05 for ADAM17). Logistic regression analysis determined that T2DM was the main associated factor with epicardial ACE2 levels (P < .01). The highest ACE2 levels were found on patients with diabetes and obesity. ACE1 and ACE2 levels were not upregulated by antidiabetic treatment (metformin, insulin or thiazolidinedione). Its cellular levels, which were higher in epicardial than in subcutaneous stromal cells (1.61 [1.55-1.63] vs 1 [1-1.34]), were not correlated with the soluble ACE2. CONCLUSION: Epicardial fat cells expressed higher levels of ACE2 in comparison with subcutaneous fat cells, which is enhanced by diabetes and obesity presence in patients with cardiovascular disease. Both might be risk factors for SARS-CoV-2 infection.

COVID-19 y tratamiento guiado con tests de diagnóstico bioquímicos y moleculares para reducir el daño cardiaco y la cardiotoxicidad / COVID-19 and treatment guided by biochemical and molecular diagnostic tests to reduce myocardial damage and cardiotoxicity

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Enhanced oxidative stress and damage in glycated erythrocytes.

Diabetes is associated with a dramatic mortality rate due to its vascular complications. Chronic hyperglycemia in diabetes leads to enhanced glycation of erythrocytes and oxidative stress. Even though erythrocytes play a determining role in vascular complications, very little is known about how erythrocyte structure and functionality can be affected by glycation. Our objective was to decipher the impact of glycation on erythrocyte structure, oxidative stress parameters and capacity to interact with cultured human endothelial cells. In vitro glycated erythrocytes were prepared following incubation in the presence of different concentrations of glucose. To get insight into the in vivo relevance of our results, we compared these data to those obtained using red blood cells purified from diabetics or non-diabetics. We measured erythrocyte deformability, susceptibility to hemolysis, reactive oxygen species production and oxidative damage accumulation. Altered structures, redox status and oxidative modifications were increased in glycated erythrocytes. These modifications were associated with reduced antioxidant defence mediated by enzymatic activity. Enhanced erythrocyte phagocytosis by endothelial cells was observed when cultured with glycated erythrocytes, which was associated with increased levels of phosphatidylserine-likely as a result of an eryptosis phenomenon triggered by the hyperglycemic treatment. Most types of oxidative damage identified in in vitro glycated erythrocytes were also observed in red blood cells isolated from diabetics. These results bring new insights into the impact of glycation on erythrocyte structure, oxidative damage and their capacity to interact with endothelial cells, with a possible relevance to diabetes.

Edoxaban's contribution to key endothelial cell functions.

BACKGROUND: We aimed to study the effects of the new oral anticoagulant edoxaban, a factor X activated (FXa) inhibitor, on key endothelial functions that could contribute to cardiovascular benefit. METHODS: Human umbilical endothelial cells (HUVEC) were obtained from donated umbilical cords and used to analyse 1) structural functions like cell proliferation, migration, and angiogenesis in appropriate assays; 2) anti-inflammatory reactions as mononuclear cell (PBMC) or platelet adhesion to HUVEC monolayers; and 3) haemostasis control by fibrin formation or plasminogen activator modulation. Key molecular effectors and signalling pathways on each function were explored by profiled protein arrays, mRNA, or protein expression analyses. RESULTS: Edoxaban promoted viability and growth in HUVEC cultures, as well as counteracted the promigratory and antiangiogenic effects of FXa, through action on the PI3K/AKT pathway. Edoxaban inhibited the adhesion to endothelial cells and the transmigration through endothelial monolayers of PBMC, and even counteracted the action of pro-inflammatory stimuli such as FXa by blocking the FXa-induced expression of cell adhesion molecules via the PAR 1-2/PI3K/NF-kB pathway. Haemostatic control of edoxaban could be exerted from the endothelium by the reduction of platelets' adhesion to endothelial cells and the possible acute activation of urokinase plasminogen activator. CONCLUSIONS: Edoxaban is a safe and structural stabilizing factor for endothelial cells and also has remarkable anti-inflammatory action, preventing PBMC adhesion and transmigration through the endothelium. It may also contribute to haemostasis control by reducing platelet adhesion. Its main molecular mechanism seems to be the control of the PI3K/NF-κB pathways.