Multidimensional Proteomic Approach of Endothelial Progenitors Demonstrate Expression of KDR Restricted to CD19 Cells

Low Phosphatidylserine+ Cells Within the CD34+/CD45dim/CD117(c-kit)+ Subpopulation Are Associated with Poor Outcomes in Metastatic Colorectal Cancer

BACKGROUND

Colorectal cancer is among the most prevalent causes of tumor-related deaths worldwide. Antiangiogenic therapy represents a cornerstone of metastatic CRC treatment, and biomarkers are advocated for the optimization of this therapeutic strategy.

METHODS

In this observational prospective study, we employed an optimized flow cytometry protocol to investigate the prognostic and predictive potential of blood circulating endothelial cells (CECs), circulating endothelial progenitor cells (CEPCs), and related subsets in a cohort of patients with metastatic colorectal cancer (n = 40).

RESULTS

Computational FC analysis revealed a differential enrichment of blood cell clusters with a CD34+/CD45dim/CD117(c-kit)+ phenotype between responders and non-responders both to antiangiogenic and non-antiangiogenic treatments. Intriguingly, our results show that a high percentage of annexin V-negative cells in a putative circulating progenitor population with a CD34+/CD45dim/CD117+ phenotype was correlated with a reduced response to systemic anticancer treatments (p = 0.015) and worse overall survival (log-rank p = 0.03). In addition, we observed increased blood concentrations of CD34+/CD45dim/CD117+/annexin V- cells in patients with a higher number of metastatic sites (p = 0.03).

CONCLUSIONS

Overall, these findings hold promise for the identification of novel circulating biomarkers to develop more personalized treatment approaches in patients with metastatic colorectal cancer.

Comorbidities and Angiogenic Regulators Affect Endothelial Progenitor Cell Subtype Numbers in a Healthy Volunteer Control Group

Endothelial progenitor cells (EPCs) are stem cells that can repair injured blood vessels through neovascularisation. This is achieved through secretion of growth factors and endothelial maturation. EPC numbers and function have been studied to determine their diagnostic, prognostic and therapeutic potential in many ischaemic diseases such as stroke. However their activation homing and migration is not definitively understood in stroke patients. In this study, we profiled the non-stroke control group recruited into the Dunhill Medical Trust Endothelial Progenitor Cell Study. Demographic, clinical and plasma levels of angiogenic regulators of participants were analysed to determine if there was any correlation with EPC numbers, subtypes and function. Participants with diabetes had significantly supressed EPC numbers (CD45-CD34 + CD133 + KDR+) and CD34 + KDR + and KDR + EPC subtypes. Male participants had significantly lower EPC numbers compared to female participants and the proliferative capacity of endothelial colony forming cells significantly decreased with increasing participant age. Pro-angiogenic proteins such as granulocyte colony-stimulating factor and stromal cell-derived factor were positively correlated with both undifferentiated and endothelial-committed EPC subtype numbers (CD133+, KDR+, CD34 + CD133+, CD34 + KDR+), whereas anti-angiogenic proteins such as thrombospondin-1 showed a negative correlation with undifferentiated EPC subtypes (CD133+, CD34 + CD133+) but a positive correlation with endothelial-committed EPC subtype numbers (KDR+, CD34 + KDR+). These results show that EPC numbers and subtypes are affected by many factors and larger studies which can analyse and deconvolute the interactions between comorbidities, plasma biomarker levels and EPC are needed.

Mobilization of Endogenous CD34+/CD133+ Endothelial Progenitor Cells by Enhanced External Counter Pulsation for Treatment of Refractory Angina

Adult stem cell therapy via intramyocardial injection of autologous CD34+ stem cells has been shown to improve exercise capacity and reduce angina frequency and mortality in patients with refractory angina (RA). However, the cost of such therapy is a limitation to its adoption in clinical practice. Our goal was to determine whether the less costly, less invasive, and widely accessible, FDA-approved alternative treatment for RA patients, known as enhanced external counterpulsation (EECP), mobilizes endogenous CD34+ stem cells and whether such mobilization is associated with the clinical benefits seen with intramyocardial injection. We monitored changes in circulating levels of CD34+/CD133+ and CD34+/KDR+ cells in RA patients undergoing EECP therapy and in a comparator cohort of RA patients undergoing an exercise regimen known as cardiac rehabilitation. Changes in exercise capacity in both cohorts were monitored by measuring treadmill times (TT), double product (DP) scores, and Canadian Cardiovascular Society (CCS) angina scores between pre- and post-treatment treadmill stress tests. Circulating levels of CD34+/CD133+ cells increased in patients undergoing EECP and were significant (β = -2.38, p = 0.012) predictors of improved exercise capacity in these patients. CD34+/CD133+ cells isolated from RA patients could differentiate into endothelial cells, and their numbers increased during EECP therapy. Our results support the hypothesis that mobilized CD34+/CD133+ cells repair vascular damage and increase collateral circulation in RA patients. They further support clinical interventions that can mobilize adult CD34+ stem cells as therapy for patients with RA and other vascular diseases.

The Onset of Intussusceptive Angiogenesis in COVID-19 Patients Might Come from the Mobilization of Stem Cell Sub-Populations Expressing the Hemangioblast Marker CD143

COVID-19 and infectious diseases have been included in strategic development goals (SDG) of United Nations (UN). The SARS-CoV-2 pandemic has unveiled complex pathophysiological mechanisms underpinning COVID-19, notably inducing a systemic acquired vascular hemopathy characterized by endothelial dysfunction and intussusceptive angiogenesis, a rapid vascular remodeling process identified as a hallmark in severe COVID-19 cases affecting pulmonary and cardiac tissues. Stem cell migration have been proposed as significant regulators of this neoangiogenic process. In a monocentric cross-sectional study, through spectral flow cytometry analysis of peripheral blood mononuclear cells, we identified a distinct stem cell subpopulation mobilized in critical COVID-19. Indeed, by an unsupervised analysis generating a UMAP representation we highlighted eleven different clusters in critical and non-critical COVID-19 patients. Only one cluster was significantly associated to critical COVID-19 compared to non-critical patients. This cluster expressed the markers: CD45dim, CD34+, CD117+, CD147+, and CD143+, and were negative for CD133. Higher level of expression of hemangioblast markers CD143 were found in critical COVID-19 patients. This population, indicative of hemangioblast-like cells, suggests a key role in COVID-19-related neoangiogenesis, potentially driving the severe vascular complications observed. Our findings underscore the need for further investigation into the contributions of adult stem cells in COVID-19 pathology, offering new insights into therapeutic targets and interventions.

Hemocompatibility and biophysical interface of left ventricular assist devices and total artificial hearts

ABSTRACT

Over the past 2 decades, there has been a significant increase in the utilization of long-term mechanical circulatory support (MCS) for the treatment of cardiac failure. Left ventricular assist devices (LVADs) and total artificial hearts (TAHs) have been developed in parallel to serve as bridge-to-transplant and destination therapy solutions. Despite the distinct hemodynamic characteristics introduced by LVADs and TAHs, a comparative evaluation of these devices regarding potential complications in supported patients, has not been undertaken. Such a study could provide valuable insights into the complications associated with these devices. Although MCS has shown substantial clinical benefits, significant complications related to hemocompatibility persist, including thrombosis, recurrent bleeding, and cerebrovascular accidents. This review focuses on the current understanding of hemostasis, specifically thrombotic and bleeding complications, and explores the influence of different shear stress regimens in long-term MCS. Furthermore, the role of endothelial cells in protecting against hemocompatibility-related complications of MCS is discussed. We also compared the diverse mechanisms contributing to the occurrence of hemocompatibility-related complications in currently used LVADs and TAHs. By applying the existing knowledge, we present, for the first time, a comprehensive comparison between long-term MCS options.

VEGF-A plasma levels are associated with impaired DLCO and radiological sequelae in long COVID patients

BACKGROUND

Long COVID, also known as post-acute sequelae of COVID-19 (PASC), is characterized by persistent clinical symptoms following COVID-19.

OBJECTIVE

To correlate biomarkers of endothelial dysfunction with persistent clinical symptoms and pulmonary function defects at distance from COVID-19.

METHODS

Consecutive patients with long COVID-19 suspicion were enrolled. A panel of endothelial biomarkers was measured in each patient during clinical evaluation and pulmonary function test (PFT).

RESULTS

The study included 137 PASC patients, mostly male (68%), with a median age of 55 years. A total of 194 PFTs were performed between months 3 and 24 after an episode of SARS-CoV-2 infection. We compared biomarkers evaluated in PASC patients with 20 healthy volunteers (HVs) and acute hospitalized COVID-19 patients (n = 88). The study found that angiogenesis-related biomarkers and von Willebrand factor (VWF) levels were increased in PASC patients compared to HVs without increased inflammatory or platelet activation markers. Moreover, VEGF-A and VWF were associated with persistent lung CT scan lesions and impaired diffusing capacity of the lungs for carbon monoxide (DLCO) measurement. By employing a Cox proportional hazards model adjusted for age, sex, and body mass index, we further confirmed the accuracy of VEGF-A and VWF. Following adjustment, VEGF-A emerged as the most significant predictive factor associated with persistent lung CT scan lesions and impaired DLCO measurement.

CONCLUSION

VEGF-A is a relevant predictive factor for DLCO impairment and radiological sequelae in PASC. Beyond being a biomarker, we hypothesize that the persistence of angiogenic disorders may contribute to long COVID symptoms.

HIV Promotes Atherosclerosis via Circulating Extracellular Vesicle MicroRNAs

People living with HIV (PLHIV) are at a higher risk of having cerebrocardiovascular diseases (CVD) compared to HIV negative (HIVneg) individuals. The mechanisms underlying this elevated risk remains elusive. We hypothesize that HIV infection results in modified microRNA (miR) content in plasma extracellular vesicles (EVs), which modulates the functionality of vascular repairing cells, i.e., endothelial colony-forming cells (ECFCs) in humans or lineage negative bone marrow cells (lin- BMCs) in mice, and vascular wall cells. PLHIV (N = 74) have increased atherosclerosis and fewer ECFCs than HIVneg individuals (N = 23). Plasma from PLHIV was fractionated into EVs (HIVposEVs) and plasma depleted of EVs (HIV PLdepEVs). HIVposEVs, but not HIV PLdepEVs or HIVnegEVs (EVs from HIVneg individuals), increased atherosclerosis in apoE-/- mice, which was accompanied by elevated senescence and impaired functionality of arterial cells and lin- BMCs. Small RNA-seq identified EV-miRs overrepresented in HIVposEVs, including let-7b-5p. MSC (mesenchymal stromal cell)-derived tailored EVs (TEVs) loaded with the antagomir for let-7b-5p (miRZip-let-7b) counteracted, while TEVs loaded with let-7b-5p recapitulated the effects of HIVposEVs in vivo. Lin- BMCs overexpressing Hmga2 (a let-7b-5p target gene) lacking the 3'UTR and as such is resistant to miR-mediated regulation showed protection against HIVposEVs-induced changes in lin- BMCs in vitro. Our data provide a mechanism to explain, at least in part, the increased CVD risk seen in PLHIV.

Cytokines in the mechanisms of regulation of monocytopoiesis in ischemic heart disease

Introduction. The relationship of the violation of the subpopulation composition of blood monocytes in ischemic cardiomyopathy (ICMP) with changes in monocytopoiesis, as well as the effect of colony-stimulating factor of macrophages (M-CSF) and cytokines on the differentiation of monocytes of various immunophenotypes in the bone marrow is of great relevance.

Aim – to study the role of cytokines in the mechanisms of local and distant regulation of differentiation of classical, intermediate, non-classical and transitional bone marrow monocytes in combination with the content of VEGFR2+-monocytes and hypoxia-induced factor-1a (HIF-1a) in the blood of patients with ischemic heart disease (IHD), suffering and not suffering from ischemic cardiomyopathy.

Materials and methods. Seventy-four patients with IHD, suffering and not suffering from ICMP (30 and 44 people, respectively) were examined. The number of subpopulations of classical (CD14++CD16–), intermediate (CD14++CD16+), nonclassical (CD14+CD16++) and transitional (CD14+CD16–) monocytes (in bone marrow samples) and CD14+VEGFR2+-monocytes (in blood and bone marrow) was determined by flow cytofluorimetry; the concentration of cytokines IL-10, IL-13, TNF-α, IFN-γ, M-CSF in bone marrow and blood, as well as HIF-1a in the blood, was determined by ELISA.

Results. Content of hematopoietins IL-10, IL-13, TNF-α, M-CSF in the bone marrow, as well as the ability of M-CSF to activate and IL-13 to inhibit the differentiation of classical monocytes from transitional cell forms were comparable between groups of patients with IHD. In the blood of patients with ICMP the concentration of IL-10 was higher, and the content of HIF-1α and CD14+VEGFR2+-cells was lower than in patients with IHD without ICMP (IL-10 – 30.00 (26.25–34.50) pg/ mL vs. 0 (23.0–28.0) pg/mL, p < 0.05; HIF-1α – 0.040 (0.029–0.053) ng/mL vs. 0.063 (0.054–0.122) ng/mL, p < 0.05; CD14+VEGFR2+ – 7.00 (5.67–7.15) % vs. 7.80 (7.23–8.17) %, p < 0.05). A feature of monocytopoiesis in ICMP compared with patients with IHD without ICMP is a high concentration of IFN-γ in the BM and a low ratio of M-CSF/IL-13 (10.00 (0.65–18.23) and 0.02 [0–0.15) pg/mL, p < 0.001; 1.02 (0.41–2.00) and 9.00 (2.13–22.09), p < 0.05, respectively), in association with a decrease in the number of classical, intermediate monocytes and an increase in the number of transitional cells in the BM in patients with ICMP relative to patients without cardiomyopathy (21.0 (19.5–23.0) and 47 (41–61.5) %, p < 0.001; 0.3 (0.0–1.2) and 18.5 (6.5–28.0) %, p < 0.01; 76.2 (73.0–78.5) and 30.5 (13.0–41.5) %, p < 0.001, respectively). At the same time, regardless of the clinical form of IHD, IL-10 and IL-13 are distant hematopoietins, TNF-α is local hematopoietin.

Conclusion. An increase in the concentration of IFN-γ and a low ratio of M-CSF/IL-13 in the bone marrow, as well as an excess of IL-10 and a lack of HIF-1a and CD14+VEGFR2+-cells in the blood of IHD patients, are associated with inhibition of differentiation of mature forms of monocytes and the development of ICMP.

High-throughput proteomics: a methodological mini-review

Proteomics plays a vital role in biomedical research in the post-genomic era. With the technological revolution and emerging computational and statistic models, proteomic methodology has evolved rapidly in the past decade and shed light on solving complicated biomedical problems. Here, we summarize scientific research and clinical practice of existing and emerging high-throughput proteomics approaches, including mass spectrometry, protein pathway array, next-generation tissue microarrays, single-cell proteomics, single-molecule proteomics, Luminex, Simoa and Olink Proteomics. We also discuss important computational methods and statistical algorithms that can maximize the mining of proteomic data with clinical and/or other 'omics data. Various principles and precautions are provided for better utilization of these tools. In summary, the advances in high-throughput proteomics will not only help better understand the molecular mechanisms of pathogenesis, but also to identify the signature signaling networks of specific diseases. Thus, modern proteomics have a range of potential applications in basic research, prognostic oncology, precision medicine, and drug discovery.

Bioprosthetic Total Artificial Heart Implantation Does Not Induce Chronic Inflammation

The Aeson total artificial heart (A-TAH) has been developed for patients at risk of death from biventricular failure. We aimed to assess the inflammatory status in nine subjects implanted with the A-TAH in kinetics over one year. Laboratory assessment of leukocyte counts, inflammatory cytokines assay, and peripheral blood mononuclear cell collection before and after A-TAH implantation. Leukocyte counts were not significantly modulated according to time after A-TAH implantation (coefficient of the linear mixed effect model with 95% CI, -0.05 (-0.71 to -0.61); p = 0.44). We explored inflammatory cytokine after A-TAH and did not observe, at any time, a modified profile compared to pre-implantation values (all p -values > 0.05). Finally, we compared the distribution of circulating immune cell subpopulations identified based on sequential expression patterns for multiple clusters of differentiation. None of the population explored had significant modulation during the 12-month follow-up (all p -values > 0.05). In conclusion, using a cytokine multiplex assay combined with a flow cytometry approach, we demonstrated the absence of inflammatory signals in peripheral blood over a period of 12 months following A-TAH implantation.

(Epi)transcriptomics in cardiovascular and neurological complications of COVID-19

Although systemic inflammation and pulmonary complications increase the mortality rate in COVID-19, a broad spectrum of cardiovascular and neurological complications can also contribute to significant morbidity and mortality. The molecular mechanisms underlying cardiovascular and neurological complications during and after SARS-CoV-2 infection are incompletely understood. Recently reported perturbations of the epitranscriptome of COVID-19 patients indicate that mechanisms including those derived from RNA modifications and non-coding RNAs may play a contributing role in the pathogenesis of COVID-19. In this review paper, we gathered recently published studies investigating (epi)transcriptomic fluctuations upon SARS-CoV-2 infection, focusing on the brain-heart axis since neurological and cardiovascular events and their sequelae are of utmost prevalence and importance in this disease.

Regulation of Endothelial Progenitor Cell Functions in Ischemic Heart Disease: New Therapeutic Targets for Cardiac Remodeling and Repair

Ischemic heart disease (IHD) is the leading cause of morbidity and mortality worldwide. Ischemia and hypoxia following myocardial infarction (MI) cause subsequent cardiomyocyte (CM) loss, cardiac remodeling, and heart failure. Endothelial progenitor cells (EPCs) are involved in vasculogenesis, angiogenesis and paracrine effects and thus have important clinical value in alternative processes for repairing damaged hearts. In fact, this study showed that the endogenous repair of EPCs may not be limited to a single cell type. EPC interactions with cardiac cell populations and mesenchymal stem cells (MSCs) in ischemic heart disease can attenuate cardiac inflammation and oxidative stress in a microenvironment, regulate cell survival and apoptosis, nourish CMs, enhance mature neovascularization, alleviate adverse ventricular remodeling after infarction and enhance ventricular function. In this review, we introduce the definition and discuss the origin and biological characteristics of EPCs and summarize the mechanisms of EPC recruitment in ischemic heart disease. We focus on the crosstalk between EPCs and endothelial cells (ECs), smooth muscle cells (SMCs), CMs, cardiac fibroblasts (CFs), cardiac progenitor cells (CPCs), and MSCs during cardiac remodeling and repair. Finally, we discuss the translation of EPC therapy to the clinic and treatment strategies.

Dietary Modulation Alters Susceptibility to Listeria monocytogenes and Salmonella Typhimurium with or without a Gut Microbiota

Food safety has considerably improved worldwide, yet infections with foodborne human enteric pathogens, such as Listeria spp. and Salmonella spp., still cause numerous hospitalizations and fatalities. Since dietary alterations, including fiber deficiency, might impact the colonization resistance mediated by the gut microbiome, studying the diet-microbiome-pathogen axis holds promise in further understanding the pathogenesis mechanisms. Using a gnotobiotic mouse model containing a 14-member synthetic human gut microbiota (14SM), we have previously shown that dietary fiber deprivation promotes proliferation of mucin-degrading bacteria, leading to a microbiome-mediated erosion of the colonic mucus barrier, which results in an increased susceptibility toward the rodent enteric pathogen Citrobacter rodentium. Here, we sought to understand how a low-fiber diet affects susceptibility to Listeria monocytogenes and Salmonella enterica serovar Typhimurium by using our 14SM gnotobiotic mouse model in BALB/c and C57BL/6 mouse backgrounds, respectively. Intriguingly, and in contrast to our results with C. rodentium, we observed that depriving mice of dietary fiber protected them from infections with both pathogens, compared to mice fed a standard chow. The microbiome delayed the overall pathogenicity compared to the onset of disease observed in germfree control mice. Nevertheless, we observed the same effect of diet on germfree mice, suggesting that the susceptibility is directly driven by the diet itself even in the absence of the gut microbiome. Our study points out an important observation, namely, that dietary fiber plays a crucial role in either the host's susceptibility, the virulence of these pathogens, or both. It would be judicious to design and interpret future studies on this basis. IMPORTANCE The human enteric pathogens Listeria monocytogenes and Salmonella Typhimurium are employed as classical models in rodent hosts to understand the pathogenesis mechanisms of foodborne pathogens. Research in the past decade has stressed the importance of the gut microbial composition in modulating susceptibility to these pathogens. The results of our study-using gnotobiotic mice and germfree control animals-additionally suggest that the dietary fiber components can dominate the impact of enteropathogenic virulence over the pathogenicity-modulating properties of the gut microbiome. The significance of our research is that there is a need to carefully choose a certain chow when performing the enteropathogen-associated mouse experiments and to cautiously match the rodent diets when trying to replicate experiments across different laboratories. Finally, our data underscore the importance of using germfree control animals to study these pathogens, as our findings would have been prone to misinterpretation in the absence of these controls.

Current concepts on endothelial stem cells definition, location, and markers

Ischemic vascular disease is a major cause of mortality and morbidity worldwide, and regeneration of blood vessels in perfusion-deficient tissues is a worthwhile therapeutic goal. The idea of delivering endothelial stem/progenitor cells to repair damaged vasculature, reperfuse hypoxic tissue, prevent cell death, and consequently diminish tissue inflammation and fibrosis has a strong scientific basis and clinical value. Various labs have proposed endothelial stem/progenitor cell candidates. This has created confusion, as there are profound differences between these cell definitions based on isolation methodology, characterization, and reparative biology. Here, a stricter definition based on stem cell biology principles is proposed. Although preclinical studies have often been promising, results from clinical trials have been highly contradictory and served to highlight multiple challenges associated with disappointing therapeutic benefit. This article reviews recent accomplishments in the field and discusses current difficulties when developing endothelial stem cell therapies. Emerging evidence that disputes the classic view of the bone marrow as the source for these cells and supports the vascular wall as the niche for these tissue-resident endothelial stem cells is considered. In addition, novel markers to identify endothelial stem cells, including CD157, EPCR, and CD31low VEGFR2low IL33+ Sox9+ , are described.

Elevated Circulating Stem Cells Level is Observed One Month After Implantation of Carmat Bioprosthetic Total Artificial Heart

The Aeson® total artificial heart (A-TAH) has been developed as a total heart replacement for patients at risk of death from biventricular failure. We previously described endothelialization of the hybrid membrane inside A-TAH probably at the origin of acquired hemocompatibility. We aimed to quantify vasculogenic stem cells in peripheral blood of patients with long-term A-TAH implantation. Four male adult patients were included in this study. Peripheral blood mononuclear cells were collected before A-TAH implantation (T0) and after implantation at one month (T1), between two and five months (T2), and then between six and twelve months (T3). Supervised analysis of flow cytometry data confirmed the presence of the previously identified Lin^-CD133⁺CD45^- and Lin^-CD34⁺ with different CD45 level intensities. Lin^-CD133⁺CD45^-, Lin^-CD34⁺CD45^- and Lin^-CD34⁺CD45⁺ were not modulated after A-TAH implantation. However, we demonstrated a significant mobilization of Lin^-CD34⁺CD45^dim (p = 0.01) one month after A-TAH implantation regardless of the expression of CD133 or c-Kit. We then visualized data for the resulting clusters on a uniform manifold approximation and projection (UMAP) plot showing all single cells of the live Lin^- and CD34⁺ events selected from down sampled files concatenated at T0 and T1. The three clusters upregulated at T1 are CD45^dim clusters, confirming our results. In conclusion, using a flow cytometry approach, we demonstrated in A-TAH-transplanted patients a significant mobilization of Lin^-CD34⁺CD45^dim in peripheral blood one month after A-TAH implantation. Using a flow cytometry approach, we demonstrated in A-TAH transplanted patients a significant mobilization of Lin^-CD34⁺CD45^dim in peripheral blood one month after A-TAH implantation. This cell population could be at the origin of newly formed endothelial cells on top of hybrid membrane in Carmat bioprosthetic total artificial heart.

COVID-19 is a systemic vascular hemopathy: insight for mechanistic and clinical aspects

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is presenting as a systemic disease associated with vascular inflammation and endothelial injury. Severe forms of SARS-CoV-2 infection induce acute respiratory distress syndrome (ARDS) and there is still an ongoing debate on whether COVID-19 ARDS and its perfusion defect differs from ARDS induced by other causes. Beside pro-inflammatory cytokines (such as interleukin-1 β [IL-1β] or IL-6), several main pathological phenomena have been seen because of endothelial cell (EC) dysfunction: hypercoagulation reflected by fibrin degradation products called D-dimers, micro- and macrothrombosis and pathological angiogenesis. Direct endothelial infection by SARS-CoV-2 is not likely to occur and ACE-2 expression by EC is a matter of debate. Indeed, endothelial damage reported in severely ill patients with COVID-19 could be more likely secondary to infection of neighboring cells and/or a consequence of inflammation. Endotheliopathy could give rise to hypercoagulation by alteration in the levels of different factors such as von Willebrand factor. Other than thrombotic events, pathological angiogenesis is among the recent findings. Overexpression of different proangiogenic factors such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF-2) or placental growth factors (PlGF) have been found in plasma or lung biopsies of COVID-19 patients. Finally, SARS-CoV-2 infection induces an emergency myelopoiesis associated to deregulated immunity and mobilization of endothelial progenitor cells, leading to features of acquired hematological malignancies or cardiovascular disease, which are discussed in this review. Altogether, this review will try to elucidate the pathophysiology of thrombotic complications, pathological angiogenesis and EC dysfunction, allowing better insight in new targets and antithrombotic protocols to better address vascular system dysfunction. Since treating SARS-CoV-2 infection and its potential long-term effects involves targeting the vascular compartment and/or mobilization of immature immune cells, we propose to define COVID-19 and its complications as a systemic vascular acquired hemopathy.

Anticoagulation Before Hospitalization Is a Potential Protective Factor for COVID-19: Insight From a French Multicenter Cohort Study

Background

Coronavirus disease 2019 (COVID‐19) is a respiratory disease associated with thrombotic outcomes with coagulation and endothelial disorders. Based on that, several anticoagulation guidelines have been proposed. We aimed to determine whether anticoagulation therapy modifies the risk of developing severe COVID‐19.

Methods and Results

Patients with COVID‐19 initially admitted in medical wards of 24 French hospitals were included prospectively from February 26 to April 20, 2020. We used a Poisson regression model, Cox proportional hazard model, and matched propensity score to assess the effect of anticoagulation on outcomes (intensive care unit admission or in‐hospital mortality). The study enrolled 2878 patients with COVID‐19, among whom 382 (13.2%) were treated with oral anticoagulation therapy before hospitalization. After adjustment, anticoagulation therapy before hospitalization was associated with a better prognosis with an adjusted hazard ratio of 0.70 (95% CI, 0.55–0.88). Analyses performed using propensity score matching confirmed that anticoagulation therapy before hospitalization was associated with a better prognosis, with an adjusted hazard ratio of 0.43 (95% CI, 0.29–0.63) for intensive care unit admission and adjusted hazard ratio of 0.76 (95% CI, 0.61–0.98) for composite criteria intensive care unit admission or death. In contrast, therapeutic or prophylactic low‐ or high‐dose anticoagulation started during hospitalization were not associated with any of the outcomes.

Conclusions

Anticoagulation therapy used before hospitalization in medical wards was associated with a better prognosis in contrast with anticoagulation initiated during hospitalization. Anticoagulation therapy introduced in early disease could better prevent COVID‐19–associated coagulopathy and endotheliopathy, and lead to a better prognosis.

Usefulness of Plasma SARS-CoV-2 RNA Quantification by Droplet-based Digital PCR to Monitor Treatment Against COVID-19 in a B-cell Lymphoma Patient

We report the case of an HIV-1-infected patient, treated with anti-CD20 monoclonal antibody for a B-cell lymphoma previously treated by autologous stem cell transplant. He suffered from chronic COVID19 and we monitored by plasma SARS-CoV-2 RNA by highly sensitive droplet-based digital PCR technology (ddPCR). Under tocilizumab therapy and despite a first clinical improvement biologically associated with decreasing inflammatory markers, a slight increase of SARS-CoV-2 RNAaemia quantified by ddPCR was highlighted, confirming the absence of viral efficacy of this treatment and predicting the subsequent observed deterioration. As expected, his complete recovery, finally achieved after COVID-19 convalescent plasmatherapy, strictly paralleled plasma SARS-CoV-2 RNA clearance. With these results, we confirmed the interest of SARS-CoV-2 RNAaemia monitoring by ddPCR in COVID-19 patients, particularly during treatment, and firstly showed that this new and specific biomarker could be helpful to select eligible patient for anti-IL6 receptors therapy considering the variable levels of efficacy recently observed with such therapy.

Safety and efficacy of autologous non-hematopoietic enriched stem cell nebulization in COVID-19 patients: a randomized clinical trial, Abu Dhabi 2020

BACKGROUND

The novel SARS-CoV-2 has caused the coronavirus disease 2019 (COVID-19) pandemic. Currently, with insufficient worldwide vaccination rates, identifying treatment solutions to reduce the impact of the virus is urgently needed.

METHOD

An adaptive, multicentric, open-label, and randomized controlled phase I/II clinical trial entitled the "SENTAD-COVID Study" was conducted by the Abu Dhabi Stem Cells Center under exceptional conditional approval by the Emirates Institutional Review Board (IRB) for COVID-19 Research Committee from April 4th to July 31st, 2020, using an autologous peripheral blood non-hematopoietic enriched stem cell cocktail (PB-NHESC-C) administered by compressor (jet) nebulization as a complement to standard care therapy. The primary endpoints include safety and efficacy assessments, adverse events, the mortality rate within 28 days, and the time to clinical improvement as measured by a 2-point reduction on a seven-category ordinal scale or discharge from the hospital whichever occurred first.

RESULTS

The study included a total of 139 randomized COVID-19 patients, with 69 in the experimental group and 70 in the control group (standard care). Overall survival was 94.20% for the cocktail-treated group vs. 90.27% for the control group. Adverse events were reported in 50 (72.46%) patients receiving PB-NHESC-C and 51 (72.85%) in the control group (p = 0.9590), with signs and symptoms commonly found in COVID-19. After the first 9 days of the intervention, 67.3% of cocktail-treated patients recovered and were released from hospitals compared to 53.1% (RR = 0.84; 95% CI, 0.56-1.28) in the control group. Improvement, i.e., at least a 2-point reduction in the severity scale, was more frequently observed in cocktail-treated patients (42.0%) than in controls (17.0%) (RR = 0.69; 95% CI, 0.56-0.88).

CONCLUSIONS

Cocktail treatment improved clinical outcomes without increasing adverse events. Thus, the nebulization of PB-NHESC-C was safe and effective for treatment in most of these patients.

TRIAL REGISTRATION

ClinicalTrials.gov. NCT04473170. It was retrospectively registered on July 16th, 2020.