[Clinical characteristics and follow-up of 60 patients with recent diagnosis of giant cell arteritis, NEWTON study]

INTRODUCTION

The management of giant cell arteritis (GCA) has evolved with the arrival of tocilizumab (TCZ) and the use of PET/CT. Our objective is to describe the characteristics and followup of patients with recent diagnosis of GCA in current care.

PATIENTS AND METHODS

The NEWTON cohort is a monocentric retrospective cohort based on data collected from 60 GCA patients diagnosed between 2017 and 2022 according to the ACR/EULAR 2022 criteria.

RESULTS

The median age at diagnosis was 73 [68.75; 81] years old. At diagnosis, the main manifestations were unusual temporal headaches in 48 (80 %) and an inflammatory syndrome in 50 (83 %) patients. Temporal artery biopsy confirmed the diagnosis in 49/58 (84 %) patients. Doppler of the temporal arteries found a halo in 12/23 (52 %) patients. The PET/CT found hypermetabolism in 19/43 (44 %) patients. Prednisone was stopped in 17.5 [12.75; 24.25] months. During follow-up, 22 (37 %) patients received TCZ. At least one complication of corticosteroid therapy was observed in 22 (37 %) patients. After a median follow-up of 24 [12; 42] months, 25 (42 %) patients relapsed. At the end of the follow-up, 29 (48.3 %) patients were weaned from corticosteroid therapy and 15 (25 %) were on TCZ.

CONCLUSION

Despite the increasing use of TCZ in the therapeutic arsenal and of the PET/CT in the imaging tools of GCA patients, relapses and complications of corticosteroid therapy remain frequent, observed in more than a third of patients.

Endothelin Receptor Blockade Improves Cerebral Blood Flow-Mediated Dilation in a Mouse Model of Alzheimer's Disease

INTRODUCTION

Cerebral blood flow (CBF) is reduced in patients with Alzheimer's disease (AD). Flow-mediated dilation (FMD), which plays a key role in the regulation of blood flow, is attenuated by endothelin-1. We hypothesized that endothelin receptor blockade may improve CBF in AD.

METHODS

We investigated cerebrovascular reactivity in a mouse model of AD (APP-PS1; 5-6-month-old male subjects). We assessed the in vivo response to normoxic hypercapnia and in vitro FMD in isolated cerebral and mesenteric resistance arteries before and after endothelin receptor blockade (bosentan).

RESULTS

Normoxic hypercapnia increased basilar trunk blood flow velocity (+12.3 ± 2.4%; p = 0.006, n = 6) in wild-type (WT) mice but reduced blood flow in APP-PS1 mice (-11.4 ± 1.2%; p < 0.0001, n = 8). Bosentan (50 mg/kg, acute intraperitoneal injection) restored cerebrovascular reactivity in APP-PS1 mice (+10.2 ± 2.2%; p < 0.0001, n = 8) but had no effect in WT. FMD was reduced in the posterior cerebral artery of APP-PS1 compared to WT and was normalized by bosentan (1 μmol/L, 30 min, or 50 mg/kg/day for 28 days). FMD was similar in the mesenteric artery of APPS-PS1 and WT.

CONCLUSION

APP-PS1 mice exhibited cerebrovascular endothelial dysfunction. Acute and chronic blockade of endothelin receptors restored endothelial vasomotor function, suggesting a promising therapeutic approach to restoring cerebral vasoreactivity in AD.

Autophagy protein 5 controls flow-dependent endothelial functions

Dysregulated autophagy is associated with cardiovascular and metabolic diseases, where impaired flow-mediated endothelial cell responses promote cardiovascular risk. The mechanism by which the autophagy machinery regulates endothelial functions is complex. We applied multi-omics approaches and in vitro and in vivo functional assays to decipher the diverse roles of autophagy in endothelial cells. We demonstrate that autophagy regulates VEGF-dependent VEGFR signaling and VEGFR-mediated and flow-mediated eNOS activation. Endothelial ATG5 deficiency in vivo results in selective loss of flow-induced vasodilation in mesenteric arteries and kidneys and increased cerebral and renal vascular resistance in vivo. We found a crucial pathophysiological role for autophagy in endothelial cells in flow-mediated outward arterial remodeling, prevention of neointima formation following wire injury, and recovery after myocardial infarction. Together, these findings unravel a fundamental role of autophagy in endothelial function, linking cell proteostasis to mechanosensing.

Imaging Cerebral Arteries Tortuosity and Velocities by Transcranial Doppler Ultrasound Is a Reliable Assessment of Brain Aneurysm in Mouse Models

Background

During the past few decades, several pathophysiological processes contributing to intracranial aneurysm (IA) rupture have been identified, including irregular IA shape, altered hemodynamic stress within the IA, and vessel wall inflammation. The use of preclinical models of IA and imaging tools is paramount to better understand the underlying disease mechanisms.

Methods

We used 2 established mouse models of IA, and we analyzed the progression of the IA by magnetic resonance imaging, transcranial Doppler, and histology.

Results

In both models of IA, we observed, by transcranial Doppler, a significant decrease of the blood velocities and wall shear stress of the internal carotid arteries. We also observed the formation of tortuous arteries in both models that were correlated with the presence of an aneurysm as confirmed by magnetic resonance imaging and histology. A high grade of tortuosity is associated with a significant decrease of the mean blood flow velocities and a greater artery dilation.

Conclusions

Transcranial Doppler is a robust and convenient imaging method to evaluate the progression of IA. Detection of decreased blood flow velocities and increased tortuosity can be used as reliable indicators of IA.

Impairment of central retinal artery hemodynamics in affected and fellow eyes in giant cell arteritis patients with unilateral vision loss

OBJECTIVES

Permanent visual impairment is a major complication of giant cell arteritis (GCA). We investigated the added value of color Doppler imaging (CDI) of the central retinal artery (CRA) in patients with suspected GCA for early risk evaluation before temporal artery biopsy (TAB) results become available.

METHODS

We conducted a non-interventional observational study of 30 consecutive patients hospitalized for suspected GCA, including a comprehensive analysis of clinical, laboratory, imaging, CDI and pathology data. GCA was diagnosed or excluded (GCA+, GCA-, respectively) according to American College of Rheumatology (ACR) criteria and TAB findings. Three patients not meeting ACR criteria were excluded secondarily. The GCA- group contained ten patients, and the GCA+ group contained 17 patients, including eight with unilateral, transient or permanent clinical visual impairment (CVI).

RESULTS

Mean blood flow velocity (mBFV) in the CRA was impaired in the affected eyes of GCA + CVI+ patients (1.9 ± 0.9 cm.s^-1, p < 0.001) relative to controls (4.1 ± 1.0 cm.s^-1), GCA- patients (3.6 ± 0.7 cm.s^-1) and GCA + CVI- patients (3.8 ± 0.8 cm.s^-1). The mBFVs of the CRA was similar for affected and fellow eyes (right or left). CRA mBFV measurements effectively differentiated between patients with and without CVI (ROC-curve analysis, AUC = 0.925 [95%CI: 0.700 to 0.996], p < 0.0001, 88% sensitivity, 89% specificity, and cutoff of ≤2.7 cm.s^-1 for affected eyes; 75% sensitivity, 100% specificity and cutoff of ≤2.2 cm.s^-1 for fellow eyes).

CONCLUSION

CDI facilities the early detection of visual ischemia risk in GCA+ patients, justifying urgent high-dose corticosteroid administration to save at least the fellow eye before pathology results become available.

Elevated Brain Natriuretic Peptide and High Brachial Pulse Pressure in Patients With Diabetes

BACKGROUND

Heart failure (HF) is frequent in patients with diabetes mellitus (DM), and early detection improves prognosis. We investigated whether analysis of brachial blood pressure (BP) in daily practice can identify patients with DM and high risk for subsequent HF, as defined by brain natriuretic peptide (BNP) >50 pg/ml.

METHODS

3,367 outpatients with DM without a history of cardiovascular disease were enrolled in a prospective study.

RESULTS

Age (mean ± SD) was 56 ± 14 years, 57% were male, 78% had type 2 DM, and HbA1C was 7.4 ± 1.4%. A history of hypertension was recorded in 43% of patients and uncontrolled BP was observed in 13%. BNP concentration (mean ± SD) was 21 ± 21 ng/l and 9% of patients had high risk of incident HF. Brachial pulse pressure (PP) was the best BP parameter associated with high risk of incident HF compared with diastolic, systolic, or mean BP (area under the receiver operating characteristic curve: 0.70, 0.65, 0.57, and 0.57, respectively). A multivariate analysis demonstrated that elevated PP was independently associated with high risk of incident HF (odds ratio [95% confidence interval, CI]: 2.1 [1.5-2.8] for PP ≥65 mm Hg). Study of central aortic BP and pulse wave velocity on 117 patients demonstrated that high risk of incident HF was associated with increased arterial stiffness and subendocardial ischemia. After a mean follow-up of 811 days, elevated PP was associated with increased all-cause mortality (hazard ratio [95% CI]: 1.7 [1.1-2.8]).

CONCLUSIONS

Brachial PP is powerful and independent "easy to record" BP parameter associated with high risk of incident HF in diabetic patients.

Characteristics of deep vein thrombosis in the critically ill COVID-19 patient - an observational cohort study with Doppler ultrasound measurements

OBJECTIVE

COVID-19 is associated with an increased prevalence of deep venous thrombosis (DVT), mainly in the lower limbs. However, the characteristics and rheological conditions, which contribute to facilitating DVT occurrence have been poorly investigated. We aimed to report DVT characteristics, vein diameters and peak blood flow velocities (PBFV) in the common femoral veins (CFVs) of critically ill COVID-19 patients.

PATIENTS AND METHODS

We conducted a prospective single-center cohort study in March-October 2020 including all consecutive mechanically ventilated COVID-19 adults. Doppler ultrasound of the lower limbs was performed systematically during the first week of hospitalization. In DVT-free patients, a second Doppler ultrasound was performed seven days later. Data are expressed as medians (interquartile ranges) or percentages. Comparisons were performed using Mann-Whiney and Wilcoxon signed-rank tests or Fischer's exact tests, as appropriate.

RESULTS

Fifty-five patients [age, 63 years (56-74); female/male ratio, 0.62; body-mass index, 29 kg/m2 (26-33); hypertension, 47%; diabetes, 38%; ischemic heart disease, 11%] were included. DVT was diagnosed in 19 patients (35%) including in 5 femoral (9%), 2 popliteal (4%) and 12 below-the-knee sites (22%). CFV diameter was increased to 12.0 mm (11.0-15.0) (normal range, 9.1-12) and PBFV reduced to 11.9 cm/s (8.8-15.8) (normal range, 21.3-49.2) [right-side values]. In four patients who had ultrasound before intubation, CFV diameter increased from 12.5 mm (11.8-13.3) before to 14 mm (13.6-15.3) after intubation (p = 0.008).

CONCLUSIONS

DVT in the CFV occurred in 9% of the critically ill COVID-19 patients with an overall 35%-DVT prevalence. Venous return difficulty evidenced by larger than normal CFV diameters and lower than normal PBFVs may have facilitated proximal DVT occurrence.

Collateral Supply in Preclinical Cerebral Stroke Models

Enhancing the collateral blood supply during the acute phase of cerebral ischemia may limit both the extension of the core infarct, by rescuing the penumbra area, and the degree of disability. Many imaging techniques have been applied to rodents in preclinical studies, to evaluate the magnitude of collateral blood flow and the time course of responses during the early phase of ischemic stroke. The collateral supply follows several different routes at the base of the brain (the circle of Willis) and its surface (leptomeningeal or pial arteries), corresponding to the proximal and distal collateral pathways, respectively. In this review, we describe and illustrate the cerebral collateral systems and their modifications following pre-Willis or post-Willis occlusion in rodents. We also review the potential pharmaceutical agents for stimulating the collateral blood supply tested to date. The time taken to establish a collateral blood flow supply through the leptomeningeal anastomoses differs between young and adult animals and between different species and genetic backgrounds. Caution is required when transposing preclinical findings to humans, and clinical trials must be performed to check the added value of pharmacological agents for stimulating the collateral blood supply at appropriate time points. However, collateral recruitment appears to be a rapid, beneficial, endogenous mechanism that can be stimulated shortly after artery occlusion. It should be considered a treatment target for use in addition to recanalization strategies.

Correlation between Ultra-Wide-Field Retinal Imaging Findings and Vascular Supra-Aortic Changes in Takayasu Arteritis

(1) Background: Takayasu arteritis (TA) is a chronic inflammatory large-vessel vasculitis. Ultra-wide-field imaging allows describing the retinal lesions in these patients and correlating them with vascular supra-aortic stenosis. (2) Methods: In total, 54 eyes of 27 patients diagnosed with TA were included, and a complete ophthalmological examination was performed, including UWF color fundus photography (UWF-CFP), fluorescein angiography (UWF-FA), and computed tomography angiography measuring supra-aortic stenosis. Eleven patients underwent Doppler ultrasound imaging assessing the blood flow velocity (BFV) in the central retinal artery (CRA). (3) Results: Microaneurysms were detected in 18.5% of eyes on fundus examination, in 24.4% of eyes on UWF-CFP, and in 94.4% of eyes on UWF-FA. The number of microaneurysms significantly correlated with the presence of an ipsilateral supra-aortic stenosis (p = 0.026), the presence of hypertension (p = 0.0011), and the duration of the disease (p = 0.007). The number of microaneurysms per eye negatively correlated with the BFV in the CRA (r = -0.61; p = 0.003). (4) Conclusions: UWF-FA improved the assessment of TA-associated retinal findings. The significant correlation between the number of microaneurysms and the BFV in the CRA gives new insight to our understanding of Takayasu retinopathy. The total number of microaneurysms could be used as an interesting prognostic factor for TA.

Étude prospective des événements thromboemboliques veineux chez les patients hospitalisés pour COVID-19 : anomalies associées de l’hémostase et suivi clinicobiologique à 6 mois

Introduction

La COVID-19 est associée à un risque élevé d’événement thromboembolique veineux (ETEV), thrombose veineuse profonde (TVP) et/ou embolie pulmonaire (EP) en particulier chez les patients hospitalisés.

Objectifs

Caractériser le déséquilibre de la balance hémostatique chez ces patients et décrire la prise en charge et l’évolution à 6 mois des patients avec ETEV.

Méthodes

Étude prospective incluant des patients consécutifs hospitalisés en réanimation ou en médecine pour COVID-19, avec :

– un écho-Doppler veineux systématique à l’admission en réanimation puis 7 jours plus tard en cas de négativité et en cas de symptômes de TVP en service de médecine ;

– un angioscanner thoracique réalisé en cas de suspicion d’EP ;

– un bilan d’hémostase réalisé à l’admission ;

– le suivi des patients ayant présenté un ETEV à 1, 3 et 6 mois afin de colliger les événements thrombotiques et hémorragiques.

Résultats

Du 17.03 au 11.04.2020, 133 patients d’âge médian 65 ans (72 % hommes) ont été hospitalisés pour COVID-19. Trente-huit patients ont présenté un ETEV (63 % TVP, 24 % EP, 13 % TVP + EP) dont 9 sont décédés pendant l’hospitalisation, 2 ont été transférés et 26 suivis. Nos résultats montrent :

– un taux de D-dimères > 3300 ng/mL prédictif d’un ETEV avec une VPP 66 % (IC95 % : 51–79) et VPN 80 % (IC95 % : 65–90) en réanimation ;

– une discordance significative entre les activités anticoagulante/chromogénique de la protéine C (p = .002 chez les patients ETEV+) évocatrice d’une résistance acquise à la protéine C activée ;

– une association entre les taux de facteur Willebrand et d’ADAMTS13 et les ETEV (p = .05 et p = .005 respectivement) d’une part et entre les taux d’ADAMTS13/D-dimères et la mortalité d’autre part ;

– des anticorps antiphospholipides présents chez 88 % des patients en réanimation, non associés à la survenue d’ETEV.

Les 26 patients suivis avec ETEV ont été traités par apixaban (22), rivaroxaban (2) ou tinzaparine (2) durant 3 à 6 mois. Un infarctus du myocarde et 2 saignements mineurs ont été recensés. Aucune récidive d’ETEV n’a été observée.

Conclusions

La fréquence élevée d’ETEV chez les patients hospitalisés pour COVID-19 est associée à un profil biologique de thrombo-inflammation, avec un déséquilibre marqué entre facteurs prothrombotiques/inhibiteurs naturels de la coagulation et de l’axe VWF/ADAMTS13. Le traitement par anticoagulant oral direct est une option thérapeutique possible pour le traitement d’un ETEV lié à une hospitalisation pour COVID-19.

Anaesthesia-Induced Transcriptomic Changes in the Context of Renal Ischemia Uncovered by the Use of a Novel Clamping Device

Ischemia is a common cause of acute kidney injury worldwide, frequently occurring in patients undergoing cardiac surgery or admitted to the intensive care unit (ICU). Thus, ischemia-reperfusion injury (IRI) remains one of the main experimental models for the study of kidney diseases. However, the classical technique, based on non-traumatic surgical clamps, suffers from several limitations. It does not allow the induction of multiple episodes of acute kidney injury (AKI) in the same animal, which would be relevant from a human perspective. It also requires a deep and long sedation, raising the question of potential anaesthesia-related biases. We designed a vascular occluding device that can be activated remotely in conscious mice. We first assessed the intensity and the reproducibility of the acute kidney injury induced by this new device. We finally investigated the role played by the anaesthesia in the IRI models at the histological, functional and transcriptomic levels. We showed that this technique allows the rapid induction of renal ischemia in a repeatable and reproducible manner, breaking several classical limitations. In addition, we used its unique specificities to highlight the renal protective effect conferred by the anaesthesia, related to the mitigation of the IRI transcriptomic program.

Blood Flow and Shear Stress Allow Monitoring of Progression and Prognosis of Tumor Diseases

In the presence of tumor angiogenesis, blood flow must increase, leading to an elevation of blood flow velocities (BFVels) and wall shear stress (WSS) in upstream native arteries. An adaptive arterial remodeling is stimulated, whose purpose lies in the enlargement of the arterial inner diameter, aiming for normalization of BFVels and WSS. Remodeling engages delayed processes that are efficient only several weeks/months after initiation, independent from those governing expansion of the neovascular network. Therefore, during tumor expansion, there is a time interval during which elevation of BFVels and WSS could reflect disease progression. Conversely, during the period of stability, BFVels and WSS drop back to normal values due to the achievement of remodeling processes. Ovarian peritoneal carcinomatosis (OPC), pseudomyxoma peritonei (PMP), and superficial arteriovenous malformations (AVMs) are diseases characterized by the development of abnormal vascular networks developed on native ones. In OPC and PMP, preoperative blood flow in the superior mesenteric artery (SMA) correlated with the per-operative peritoneal carcinomatosis index (OPC: n = 21, R = 0.79, p < 0.0001, PMP: n = 66, R = 0.63, p < 0.0001). Moreover, 1 year after surgery, WSS in the SMA helped in distinguishing patients with PMP from those without disease progression [ROC-curve analysis, AUC = 0.978 (0.902-0.999), p < 0.0001, sensitivity: 100.0%, specificity: 93.5%, cutoff: 12.1 dynes/cm²]. Similarly, WSS in the ipsilateral afferent arteries close to the lesion distinguished stable from progressive AVM [ROC-curve analysis, AUC: 0.988, (0.919-1.000), p < 0.0001, sensitivity: 93.5%, specificity: 95.7%; cutoff: 26.5 dynes/cm²]. Blood flow volume is indicative of the tumor burden in OPC and PMP, and WSS represents an early sensitive and specific vascular marker of disease progression in PMP and AVM.

Cytotoxic CD8+ T cells promote granzyme B-dependent adverse post-ischemic cardiac remodeling

Acute myocardial infarction is a common condition responsible for heart failure and sudden death. Here, we show that following acute myocardial infarction in mice, CD8⁺ T lymphocytes are recruited and activated in the ischemic heart tissue and release Granzyme B, leading to cardiomyocyte apoptosis, adverse ventricular remodeling and deterioration of myocardial function. Depletion of CD8⁺ T lymphocytes decreases apoptosis within the ischemic myocardium, hampers inflammatory response, limits myocardial injury and improves heart function. These effects are recapitulated in mice with Granzyme B-deficient CD8⁺ T cells. The protective effect of CD8 depletion on heart function is confirmed by using a model of ischemia/reperfusion in pigs. Finally, we reveal that elevated circulating levels of GRANZYME B in patients with acute myocardial infarction predict increased risk of death at 1-year follow-up. Our work unravels a deleterious role of CD8⁺ T lymphocytes following acute ischemia, and suggests potential therapeutic strategies targeting pathogenic CD8⁺ T lymphocytes in the setting of acute myocardial infarction.

Immune cells contribute to adverse remodeling following myocardial infarction. Here the authors show in mice and pigs that CD8⁺ lymphocytes release Granzyme B in the infarcted heart leading to cardiomyocyte death, enhanced inflammation and deterioration of cardiac function.

Assessment of Tumor Response in Mice with Ovarian Peritoneal Carcinomatosis using Doppler Ultrasound of the Superior Mesenteric Artery and Celiac Trunk

The goal of the work described here was to assess the performance of Doppler ultrasound (US) of the superior mesenteric artery (SMA) and celiac trunk (CT) in the evaluation of tumor response in female mice with ovarian peritoneal carcinomatosis treated either with bevacizumab or with carboplatin. Compared with untreated mice, carboplatin-treated mice had a lower weight (23.3 ± 2.0 vs. 27.9 ± 2.9 g, p < 0.001), peritoneal carcinomatosis index (PCI, 11 ± 3 vs. 28 ± 6, p < 0.001), Ki67-positive staining surfaces (p < 0.001), vascular density (p < 0.001), mean blood flow velocity (mBFVel) in the SMA (7.0 ± 1.4 vs. 10.9 ± 1.8 cm/s, p < 0.001) and CT (8.0 ± 1.8 vs. 14.3 ± 4.6 cm/s, p < 0.001) and no ascites. Weight and mBFVel were similar in bevacizumab-treated and untreated mice. The mBFVels in the SMA and CT correlated with the PCI used as an estimation of the tumor burden, R = 0.70 (p < 0.0001) and R = 0.65 (p < 0.0001), respectively. Doppler US allows non-invasive assessment of the effects of anticancer therapy in ovarian peritoneal carcinomatosis-induced mice.

Endothelial S1P1 Signaling Counteracts Infarct Expansion in Ischemic Stroke

RATIONALE

Cerebrovascular function is critical for brain health, and endogenous vascular protective pathways may provide therapeutic targets for neurological disorders. S1P (Sphingosine 1-phosphate) signaling coordinates vascular functions in other organs, and S1P1 (S1P receptor-1) modulators including fingolimod show promise for the treatment of ischemic and hemorrhagic stroke. However, S1P1 also coordinates lymphocyte trafficking, and lymphocytes are currently viewed as the principal therapeutic target for S1P1 modulation in stroke.

OBJECTIVE

To address roles and mechanisms of engagement of endothelial cell S1P1 in the naive and ischemic brain and its potential as a target for cerebrovascular therapy.

METHODS AND RESULTS

Using spatial modulation of S1P provision and signaling, we demonstrate a critical vascular protective role for endothelial S1P1 in the mouse brain. With an S1P1 signaling reporter, we reveal that abluminal polarization shields S1P1 from circulating endogenous and synthetic ligands after maturation of the blood-neural barrier, restricting homeostatic signaling to a subset of arteriolar endothelial cells. S1P1 signaling sustains hallmark endothelial functions in the naive brain and expands during ischemia by engagement of cell-autonomous S1P provision. Disrupting this pathway by endothelial cell-selective deficiency in S1P production, export, or the S1P1 receptor substantially exacerbates brain injury in permanent and transient models of ischemic stroke. By contrast, profound lymphopenia induced by loss of lymphocyte S1P1 provides modest protection only in the context of reperfusion. In the ischemic brain, endothelial cell S1P1 supports blood-brain barrier function, microvascular patency, and the rerouting of blood to hypoperfused brain tissue through collateral anastomoses. Boosting these functions by supplemental pharmacological engagement of the endothelial receptor pool with a blood-brain barrier penetrating S1P1-selective agonist can further reduce cortical infarct expansion in a therapeutically relevant time frame and independent of reperfusion.

CONCLUSIONS

This study provides genetic evidence to support a pivotal role for the endothelium in maintaining perfusion and microvascular patency in the ischemic penumbra that is coordinated by S1P signaling and can be harnessed for neuroprotection with blood-brain barrier-penetrating S1P1 agonists.

Pathophysiological Processes Underlying the High Prevalence of Deep Vein Thrombosis in Critically Ill COVID-19 Patients

Coronavirus disease 2019 (COVID-19) predisposes to deep vein thrombosis (DVT) and pulmonary embolism (PE) particularly in mechanically ventilated adults with severe pneumonia. The extremely high prevalence of DVT in the COVID-19 patients hospitalized in the intensive care unit (ICU) has been established between 25 and 84% based on studies including systematic duplex ultrasound of the lower limbs when prophylactic anticoagulation was systematically administrated. DVT prevalence has been shown to be markedly higher than in mechanically ventilated influenza patients (6–8%). Unusually high inflammatory and prothrombotic phenotype represents a striking feature of COVID-19 patients, as reflected by markedly elevated reactive protein C, fibrinogen, interleukin 6, von Willebrand factor, and factor VIII. Moreover, in critically ill patients, venous stasis has been associated with the prothrombotic phenotype attributed to COVID-19, which increases the risk of thrombosis. Venous stasis results among others from immobilization under muscular paralysis, mechanical ventilation with high positive end-expiratory pressure, and pulmonary microvascular network injuries or occlusions. Venous return to the heart is subsequently decreased with increase in central and peripheral venous pressures, marked proximal and distal veins dilation, and drops in venous blood flow velocities, leading to a spontaneous contrast “sludge pattern” in veins considered as prothrombotic. Together with endothelial lesions and hypercoagulability status, venous stasis completes the Virchow triad and considerably increases the prevalence of DVT and PE in critically ill COVID-19 patients, therefore raising questions regarding the optimal doses for thromboprophylaxis during ICU stay.

Imbalance between procoagulant factors and natural coagulation inhibitors contributes to hypercoagulability in the critically ill COVID-19 patient: clinical implications

OBJECTIVE

Coronavirus Disease-2019 (COVID-19) predisposes patients to thrombosis which underlying mechanisms are still incompletely understood. We sought to investigate the balance between procoagulant factors and natural coagulation inhibitors in the critically ill COVID-19 patient and to evaluate the usefulness of hemostasis parameters to identify patients at risk of venous thromboembolic event (VTE).

PATIENTS AND METHODS

We conducted an observational study recording VTEs defined as deep vein thrombosis or pulmonary embolism using lower limb ultrasound (92% of the patients), computed tomography pulmonary angiography (6%) and both tests (2%). We developed a comprehensive analysis of hemostasis.

RESULTS

Ninety-two consecutive mechanically ventilated COVID-19 patients (age, 62 years [53-69] (median [25th-75th percentiles]); M/F sex ratio, 2.5; body-mass index, 28 kg/m2 [25-32]; past hypertension (52%) and diabetes mellitus (30%)) admitted to the Intensive Care Unit (ICU) from 03/11/2020 to 5/05/2020, were included. When tested, patients were receiving prophylactic (74%) or therapeutic (26%) anticoagulation. Forty patients (43%) were diagnosed with VTE. Patients displayed inflammatory and prothrombotic profile including markedly elevated plasma fibrinogen (7.7 g/L [6.1-8.6]), D-dimer (3,360 ng/mL [1668-7575]), factor V (166 IU/dL [136-195]) and factor VIII activities (294 IU/dL [223-362]). We evidenced significant discrepant protein C anticoagulant and chromogenic activities, combined with slightly decreased protein S activity. Plasma D-dimer >3,300 ng/mL predicted VTE presence with 78% (95%-confidence interval (95% CI), 62-89) sensitivity, 69% (95% CI, 55-81) specificity, 66% (95% CI, 51-79) positive predictive value and 80% (95% CI, 65-90) negative predictive value [area under the ROC curve, 0.779 (95%CI, 0.681-0.859), p=0.0001].

CONCLUSIONS

Mechanically ventilated COVID-19 patients present with an imbalance between markedly increased factor V/VIII activity and overwhelmed protein C/S pathway. Plasma D-dimer may be a useful biomarker at the bedside for suspicion of VTE.

How to screen and diagnose deep venous thrombosis (DVT) in patients hospitalized for or suspected of COVID-19 infection, outside the intensive care units

Introduction

The Coronavirus disease-2019 outbreak (COVID-19) has been declared a pandemic by the World Health Organization. Studies report both a severe inflammatory syndrome and a procoagulant state in severe COVID-19 cases, with an increase of venous thromboembolism, including pulmonary embolism (PE) and deep vein thrombosis (DVT). In this context, we discuss the use of doppler ultrasonography (DUS) in the screening and diagnosis of DVT in ambulatory and hospitalized patients with, or suspected of having, COVID-19, outside the intensive care unit (ICU).

Material and methods

Non-systematic review of the literature.

Results

In patients hospitalized for or suspected of COVID-19 infection with the presence of either (a) DVT clinical symptoms, (b) a strong DVT clinical probability (Wells score > 2) or (c) elevated D-dimer levels without DVT clinical symptoms and without PE on lung CT angio-scan, DVT should be investigated with DUS. In the presence of PE diagnosed clinically and/or radiologically, additional systematic DVT screening using DUS is not recommended during the COVID-19 pandemic. The use of 4-points compression DUS for DVT screen and diagnosis is the most appropriate method in this context.

Discussion

Systematic DUS for DVT screening in asymptomatic COVID patients is not recommended unless the patient is in the ICU. This would increase the risk of unnecessarily exposing medical staff to SARS-CoV-2 and monopolizing limited resources during this period.

Abstract 1636: Diet-variants and immune characterization of a stage-defined, transgenic immunocompetent mouse model of HCC (ASV-B)

Background: Non-alcoholic fatty liver disease (NAFLD), especially non-alcoholic steatohepatitis (NASH) is a chronic liver disease commonly associated with hepatic fibrosis. NASH patients have an increased risk for hepatocellular carcinoma (HCC). Due to western way of life, NASH incidence is rising and predicted to become the leading cause of liver transplant in 2020 and of HCC in the next decades. There is an urgent need for robust animal models fully recapitulating the NASH-related HCC carcinogenesis due to this changing in HCC etiology. In this study, we develop and characterize specific diet-induced variants from our transgenic HCC mouse model, focusing on immune landscape.

Methods: We used in the whole study ASV-B mice: a transgenic mouse model (C57BL/6J) spontaneously developing a reproducible stage-defined HCC (hyperplasia at week(W)8, nodular stage at W12, and diffuse carcinoma at W16-20). Livers were characterized for angiogenesis and immune populations using immunostaining (IHC and IF), and qRT-PCR (LightCycler, Roche). To mimic NASH, ASV-B mice were exposed to 5 different diets. Ten ASV-B and 5 control mice were fed as follows: classic diet as control (yellow), or a high-fat diet (blue), a diet enriched with saturated fatty acids + 1.25% cholesterol (green), a diet containing 22% of vegetal oil + 0.2% cholesterol (orange), and a 1.25% cholesterol diet containing 21% of milkfat (red). All mice fed with special diets also received 30% fructose in the drink water. A second experiment was performed on ASV-B and C57BL/6J wild type mice, using control and Nash-inducing regimen, to confirm our first results.

Results: ASV-B model showed an increase in liver volume and angiogenesis, HCC livers harboring marked arterialization and capillarization as compared to control. Assessing immune markers on 7 evaluable tumor specimens, we observed an increase in CD8, Foxp3, INOS, CD11b, PD-1, PD-L1, IL1β, IFN-γ, TNF-α, IL17A and IL17F mRNA expressions, as frequently observed in human inflammatory HCC. In addition, IHC staining showed intratumoral infiltration of lymphocytes (CD8+) and macrophages (F4/80+, a well-characterized and extensively referenced mouse macrophage marker). ASV-B mice receiving yellow, blue, and green regimens showed similar liver volumes and weights. By macroscopic analysis, we observed increased liver steatosis, and fibrosis in the red and orange regimen compared to others. Moreover, we observed a 40% mortality rate in the orange regimen, and a 20% mortality rate in the blue and green regimens. Interestingly, by microscopic analysis, we observed liver steatosis and inflammation, in 100%, and 75% of the mice, respectively. These results indicate that the green regimen is the most suitable to induce NASH-underlyning disease in our transgenic HCC model. At the conference, we will show in the diet-variants, the immune landscape of the livers and the results of our ongoing second experiment.

Conclusion: ASV-B transgenic mouse model mimics several characteristics of human HCC developing on healthy liver including inflammatory reaction and immune cell infiltration. In the ASV-B model, we have been able to develop specific-diets variants mimicking NASH characteristics that could be used for drug testing.

Citation Format: Annemilaï Tijeras-Raballand, Christian Hobeika, Philippe Bonnin, Benoit Rousseau, Aurélie Rodrigues, Fouad Ladfil, Marc Pocard, Armand de Gramont, Eric Raymond, Sandrine Faivre, Valérie Paradis, Clarisse Eveno. Diet-variants and immune characterization of a stage-defined, transgenic immunocompetent mouse model of HCC (ASV-B) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1636.

Wall Shear Stress in the Feeding Native Conduit Arteries of Superficial Arteriovenous Malformations of the Lower Face is a Reliable Marker of Disease Progression

PURPOSE

 To assess the prognostic value of the wall shear stress (WSS) measured in the feeding native arteries upstream from facial superficial arteriovenous malformations (sAVMs). Reliable prognostic criteria are needed to distinguish progressive from stable sAVMs and thus support the indication for an aggressive or a conservative management to avoid severe facial disfigurement.

MATERIALS AND METHODS

 We prospectively included 25 patients with untreated facial sAVMs, 15 patients with surgically resected sAVMs and 15 controls. All had undergone Doppler ultrasound examination (DUS) with measurements of inner diameters, blood flow velocities, computation of blood flow and WSS of the feeding arteries. Based on the absence or presence of progression in clinical and imaging examinations 6 months after, we discriminated untreated patients as stable or progressive.

RESULTS

 WSS in the ipsilateral external carotid artery was higher in progressive compared to stable sAVMs (15.8 ± 3.3dynes/cm² vs. 9.6 ± 2.0dynes/cm², mean±SD, p < 0.0001) with a cut-off of 11.5dynes/cm² (sensitivity: 92 %, specificity: 92 %, AUC: 0.955, [95 %CI: 0.789-0.998], p = 0.0001). WSS in the ipsilateral facial artery was also higher in progressive compared to stable sAVMs (50.7 ± 14.5dynes/cm² vs. 25.2 ± 7.1dynes/cm², p < 0.0001) with a cut-off of 34.0dynes/cm² (sensitivity: 100 %, specificity: 92 %, AUC: 0.974, [95 %CI: 0.819-1.000], p = 0.0001). The hemodynamic data of operated patients were not different from those of the control group.

CONCLUSION

 WSS measured in the feeding arteries of an sAVM may be a simple reliable criterion to distinguish stable from progressive sAVMs. This value should be considered to guide the therapeutic strategy as well as the long-term follow-up of patients with facial sAVMs.

Iron Regulator Hepcidin Impairs Macrophage-Dependent Cardiac Repair After Injury

BACKGROUND

Defective systemic and local iron metabolism correlates with cardiac disorders. Hepcidin, a master iron sensor, actively tunes iron trafficking. We hypothesized that hepcidin could play a key role to locally regulate cardiac homeostasis after acute myocardial infarction.

METHODS

Cardiac repair was analyzed in mice harboring specific cardiomyocyte or myeloid cell deficiency of hepcidin and challenged with acute myocardial infarction.

RESULTS

We found that the expression of hepcidin was elevated after acute myocardial infarction and the specific deletion of hepcidin in cardiomyocytes failed to improve cardiac repair and function. However, transplantation of bone marrow-derived cells from hepcidin-deficient mice ( Hamp^-/-) or from mice with specific deletion of hepcidin in myeloid cells (LysM^CRE/+/ Hamp^f/f) improved cardiac function. This effect was associated with a robust reduction in the infarct size and tissue fibrosis in addition to favoring cardiomyocyte renewal. Macrophages lacking hepcidin promoted cardiomyocyte proliferation in a prototypic model of apical resection-induced cardiac regeneration in neonatal mice. Interleukin (IL)-6 increased hepcidin levels in inflammatory macrophages. Hepcidin deficiency enhanced the number of CD45⁺/CD11b⁺/F4/80⁺/CD64⁺/MHCII^Low/chemokine (C-C motif) receptor 2 (CCR2)⁺ inflammatory macrophages and fostered signal transducer and activator of transcription factor-3 (STAT3) phosphorylation, an instrumental step in the release of IL-4 and IL-13. The combined genetic suppression of hepcidin and IL-4/IL-13 in macrophages failed to improve cardiac function in both adult and neonatal injured hearts.

CONCLUSIONS

Hepcidin refrains macrophage-induced cardiac repair and regeneration through modulation of IL-4/IL-13 pathways.

Intravenous Administration of Human Adipose Derived-Mesenchymal Stem Cells Is Not Efficient in Diabetic or Hypertensive Mice Subjected to Focal Cerebral Ischemia

As the second cause of death and cognitive decline in industrialized countries, stroke is a major burden for society. Vascular risks factors such as hypertension and diabetes are involved in most stroke patients, aggravate stroke severity, but are still poorly taken into account in preclinical studies. Microangiopathy and sustained inflammation are exacerbated, likely explaining the severity of stroke in those patients. We sought to demonstrate that intravenous administration of human adipose derived-mesenchymal stem cells (hADMSC) that have immunomodulatory properties, could accelerate sensorimotor recovery, prevent long-term spatial memory impairment and promote neurogenesis, in diabetic or hypertensive mice, subjected to permanent middle cerebral artery occlusion (pMCAo). Diabetic (streptozotocin IP) or hypertensive (L-NAME in drinking water) male C57Bl6 mice subjected to pMCAo, were treated by hADMSC (500,000 cells IV) 2 days after cerebral ischemia induction. Infarct volume, neurogenesis, microglial/macrophage density, T-lymphocytes density, astrocytes density, and vessel density were monitored 7 days after cells injection and at 6 weeks. Neurological sensorimotor deficit and spatial memory were assessed until 6 weeks post-stroke. Whatever the vascular risk factor, hADMSC showed no effect on functional sensorimotor recovery or cognitive decline prevention at short or long-term assessment, nor significantly modified neurogenesis, microglial/macrophage, T-lymphocytes, astrocytes, and vessel density. This work is part of a European program (H2020, RESSTORE). We discuss the discrepancy of our results with those obtained in rats and the optimal cell injection time frame, source and type of cells according to the species stroke model. A comprehensive understanding of the mechanisms preventing recovery should help for successful clinical translation, but first could allow identifying good and bad responders to cell therapy in stroke.

Prostaglandin E1-Mediated Collateral Recruitment Is Delayed in a Neonatal Rat Stroke Model

While arterial reflow after a stroke represents an important challenge for better outcomes, it is also very important that sudden recanalization does not produce local oxidative and nitrogen species, deleterious for the brain and more particularly the immature brain. Our objective was to determine whether a supply in prostaglandin (Pg) E1 (Alprostadil), via its action on arterial pressure, might progressively improve cerebral reperfusion in a neonatal stroke model. Arterial blood flow was measured using ultrasonography. Rate-limiting and Pg terminal synthesizing enzymes were evaluated using reverse-transcriptase polymerase chain reaction. Our data suggests that a supply in PgE1 might delay and improve the ipsilateral reperfusion by decreasing thromboxane A synthase-1 gene, the density of reactive astrocytes and lesion volume.

Abstract 4096: Stage-defined, transgenic immunocompetent mouse model (ASV-B) to investigate new drugs for hepatocellular carcinoma

Background: Hepatocellular carcinoma (HCC) is a complex multistep malignancy in need of new therapeutic options often arising on underlying chronic liver disease. HCC animal models relevant to clinical situations are crucial to investigate new anticancer drugs, alone or in combination. Mice bearing xenografts and transgenic mice are the two main models used for preclinical drug development, but most of them fail to mimic the different step of HCC observed in patients. In this study, we aim to describe a stage-defined, transgenic immunocompetent HCC mouse model.

Methods: ASV-B is a transgenic mouse model that spontaneously develops, upon SV40 T-Ag oncogene expression in hepatocytes, a reproducible stage-defined HCC. Hyperplasia at week(W)8 is followed by nodular stage at W12 (multiple well-delimited tumor nodules of about 1 mm, growing progressively up to 1 cm), then diffuse carcinoma stage at W16-20. HCC is restricted to male, backcrossed with C57BL/6J mice, the female littermates being used as controls.

Results: Liver volume assessed by ultrasound at each step of carcinogenesis showed a 2.7-, 2.7-, 3.9-, and 5.8-fold increase (p&lt;0.001) in transgenic mice compared to controls (CTRL) at W8, 12, 16, and 20, respectively. ASV-B model displays marked arterialization with intense arterial flow in liver tumor similar to human HCC. Sinusoids in tumor nodules are tortuous and dilated, surrounded by activated hepatic stellate cells (HSCs) expressing smooth muscle actin (SMA) while HSCs surrounding normal sinusoids only express desmin. In addition, ASV-B livers develop along carcinogenesis a mesenchymal phenotype (increased vimentin and decreased e-cadherin staining), mimicking certain clinical situations of acquired resistance to VEGFR inhibitors. Angiogenesis, monitored using Doppler assessing blood flow velocity (BFV) in the hepatic artery, is enhanced by 29%, 51% and 156% at W8, W12 and W16, respectively, in transgenic liver animals as compared to CTRL. Increased angiogenesis was confirmed by CD31 staining in tumor specimen showing increased number of vessels per field. ASV-B model has been used to investigate the toxicity and efficacy of new drugs (galunisertib, MET/AXL inhibitor), including antiangiogenic agents (sorafenib and ramucirumab) alone or in combination, and may be relevant to explore the effects of immunotherapy agents. At the conference, we will display further characterization of liver tumors regarding vascularization, and immune cells localization using IHC.

Conclusion: ASV-B transgenic mouse model mimics several characteristics of human HCC developing on healthy liver including multinodular disease, vessel abnormalities, and dedifferentiation toward mesenchymal phenotype. Further steps will consist of characterizing the adjacent nontumor liver, and developing nonalcoolic steatohepatitis (NASH) on ASV-B model using specific diets.

Citation Format: Annemilaï Tijeras-Raballand, Patricia Hainaud, Christian Hobeika, Clarisse Eveno, Marc Pocard, Philippe Bonnin, Valérie Paradis, Mohamed Bouattour, Eric Raymond, Armand de Gramont, Evelyne Dupuy, Sandrine Faivre. Stage-defined, transgenic immunocompetent mouse model (ASV-B) to investigate new drugs for hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4096.

Abstract 2944: TGF-β inhibitor galunisertib combined with antiangiogenic therapies showed antitumor effects in vitro and in vivo in hepatocellular carcinoma (HCC)

Introduction: TGF-β pathway, associated with hepatocellular carcinoma (HCC) progression, can be targeted by galunisertib, a selective ATP-mimetic TGF-β receptor (TβR)-I inhibitor in clinical trials for HCC patients. We investigated the antitumor effects of galunisertib (Galu) combined with antiangiogenic compounds (sorafenib or DC101, a fully human monoclonal antibody antagonizing VEGFR2, mimicking ramucirumab) in HCC.

Methods: In vitro, we assessed proliferation (MTT assay), migration (wound healing), and invasion (boyden chambers), in a panel of HCC cell lines. Transgenic mice developing stage-defined HCC were treated from weeks (W)8 to W16 with either vehicle, sorafenib (30mg/kg), Galu (100mg/kg), sorafenib plus Galu, DC101 (40mg/kg, twice weekly, IP), or DC101 plus galunisertib. Tumor growth was evaluated by ultrasound (liver size) and by the number of macronodules at sacrifice. Angiogenesis assessed by Doppler measuring the mean blood flow in the coeliac trunk (TCm) and CD31 staining.

Results: In vitro, we showed an inhibition of TGF-induced proliferation, migration and proliferation by Galu, further potentiated by sorafenib. Sorafenib-tolerant cell line SK-Sora was the most sensitive to Galu. In vivo, at W12 & W16, liver size and tumor macronodules number were significantly lower in all treatment arms compared to placebo. At W16, DC101 showed increased tumor control compared to sorafenib regarding liver weight (3,75g±0,39 vs 6,31 g±0,52, p&lt;0.001) and macronodules number (75,7±12.0 vs 139±13,6, p&lt;0.001). Galu/sorafenib and Galu/DC101 combinations showed increased tumor control at W16 as compared to monotherapies. Interestingly, at W16, Galu/DC101 combination showed greater effect on liver weight (3,09g±0,70 vs 3.75g±0,21, p&lt;0.05, number of macronodules (55.1±14.8 vs 109.4±24.3, p&lt;0.001), and micronodules surface (2.0 mm2±0.43 vs 1.43 mm2±0.33, p&lt;0.05) as compared to Galu/sorafenib combination. Angiogenesis decreased in all treatment arms compared to placebo. At W16, we observed a TCm decrease over 50% in the combination arms compared to 24% with sorafenib, 26% with DC101 and 20% with Galu alone, respectively. These results were confirmed by CD31 staining for assessing number of vessels per field. In addition, Galu/sorafenib combination yielded an increased number of monocytes, a decreased number of neutrophils and Kuppfer cells, along with increased NK cells and decreased NKT cells. Dendritic cells as well as B and T cells population did not show particular variation except for CD4+CD25+ T cells that were strongly decreased in sorafenib-treated mice.

Conclusion: The combination of galunisertib with sorafenib or DC101 showed promising antitumor activities that were associated with decreased angiogenesis, DC101 displaying increased efficacy as compared to sorafenib.

Citation Format: Annemilaï Tijeras-Raballand, Christian Hobeika, Matthieu Martinet, Lucile Astorgues-Xerri, Elise Paven, Marie-Aude Le Bitoux, Anne Maillard, Clarisse Eveno, Marc Pocard, Philippe Bonnin, Alexandre Harari, Eric Raymond, Sandrine Faivre, Armand de Gramont. TGF-β inhibitor galunisertib combined with antiangiogenic therapies showed antitumor effects in vitro and in vivo in hepatocellular carcinoma (HCC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2944.

Hepatectomy increases metastatic graft and growth in an immunocompetent murine model of peritoneal metastases

BACKGROUND

Curative surgery of synchronous peritoneal metastases (PM) and colorectal liver metastases (LM) has been recently investigated as feasible option. When synchronous peritoneal and liver resection is not achievable, the sequence of the surgery remains unknown. Our hypothesis was that liver resection (LR) promotes peritoneal growth resulting in a non-resectable PM. We sought to analyse the effects of major LR and liver regeneration after hepatectomy in a murine model of PM and the associated angiogenesis.

METHODS

Murine model of colorectal PM in Balb/C mice was developed by intraperitoneal injection of different CT-26 tumour cell concentrations. Five days after the injection, mice were randomized into three groups: 68% hepatectomy group, sham laparotomy and control group without surgery. On post-operative days 1, 5 and 20, PM was evaluated macroscopically, tumour growth and liver regeneration by immunohistochemistry, and angiogenesis by immunofluorescence. Circulating progenitor cells, plasmatic cytokines and digestive arterial blood flow velocity measurements were also analysed.

RESULTS

Reproducible murine model of limited colorectal PM was obtained. Surgery induced PM increases and promoted neo-angiogenesis. Major hepatectomy influence the tumour growth in the late phase after surgery, the extent of extra-peritoneal metastasis and the increase of Ki-67 expression in the remnant liver.

CONCLUSIONS

This animal model confirms the pro-tumoural and pro-angiogenic role of surgery, laparotomy and major LR, which promotes the increase of angiogenic factors and their participation in PM growth. These results suggest that peritoneal resection should be first step in the case of two-step liver and peritoneal surgery for patients with colorectal PM and LM.

Endothelial Epas1 Deficiency Is Sufficient To Promote Parietal Epithelial Cell Activation and FSGS in Experimental Hypertension

FSGS, the most common primary glomerular disorder causing ESRD, is a complex disease that is only partially understood. Progressive sclerosis is a hallmark of FSGS, and genetic tracing studies have shown that parietal epithelial cells participate in the formation of sclerotic lesions. The loss of podocytes triggers a focal activation of parietal epithelial cells, which subsequently form cellular adhesions with the capillary tuft. However, in the absence of intrinsic podocyte alterations, the origin of the pathogenic signal that triggers parietal epithelial cell recruitment remains elusive. In this study, investigation of the role of the endothelial PAS domain-containing protein 1 (EPAS1), a regulatory α subunit of the hypoxia-inducible factor complex, during angiotensin II-induced hypertensive nephropathy provided novel insights into FSGS pathogenesis in the absence of a primary podocyte abnormality. We infused angiotensin II into endothelial-selective Epas1 knockout mice and their littermate controls. Although the groups presented with identical high BP, endothelial-specific Epas1 gene deletion accentuated albuminuria with severe podocyte lesions and recruitment of pathogenic parietal glomerular epithelial cells. These lesions and dysfunction of the glomerular filtration barrier were associated with FSGS in endothelial Epas1-deficient mice only. These results indicate that endothelial EPAS1 has a global protective role during glomerular hypertensive injuries without influencing the hypertensive effect of angiotensin II. Furthermore, these findings provide proof of principle that endothelial-derived signaling can trigger FSGS and illustrate the potential importance of the EPAS1 endothelial transcription factor in secondary FSGS.

Controlled arterial reflow after ischemia induces better outcomes in the juvenile rat brain

Our objective was to determine whether controlled reflow on one side and/or the other side after bilateral carotid occlusion release could reduce cell death in focal ischemic P14 rats. Arterial blood flow was measured using ultrasonography. Cell death, inflammation and nitrotyrosine were measured using immunofluorescence. When reflow was first induced in the contralateral side, we observed improved outcome markers compared with those when reflow was first induced in the ipsilateral side and/or simultaneous reflow was induced in both sides. Our data suggest that progressive rerouting of arterial flow through the circle of Willis toward the ischemic site reduced cell death.

Mast cells regulate myofilament calcium sensitization and heart function after myocardial infarction

Ngkelo et al. use a mast cell–deficient mouse model to reveal a protective role of mast cells in myocardial infarction, through regulation of the cardiac contractile machinery.

Acute myocardial infarction (MI) is a severe ischemic disease responsible for heart failure and sudden death. Inflammatory cells orchestrate postischemic cardiac remodeling after MI. Studies using mice with defective mast/stem cell growth factor receptor c-Kit have suggested key roles for mast cells (MCs) in postischemic cardiac remodeling. Because c-Kit mutations affect multiple cell types of both immune and nonimmune origin, we addressed the impact of MCs on cardiac function after MI, using the c-Kit–independent MC-deficient (Cpa3^Cre/+) mice. In response to MI, MC progenitors originated primarily from white adipose tissue, infiltrated the heart, and differentiated into mature MCs. MC deficiency led to reduced postischemic cardiac function and depressed cardiomyocyte contractility caused by myofilament Ca²⁺ desensitization. This effect correlated with increased protein kinase A (PKA) activity and hyperphosphorylation of its targets, troponin I and myosin-binding protein C. MC-specific tryptase was identified to regulate PKA activity in cardiomyocytes via protease-activated receptor 2 proteolysis. This work reveals a novel function for cardiac MCs modulating cardiomyocyte contractility via alteration of PKA-regulated force–Ca²⁺ interactions in response to MI. Identification of this MC-cardiomyocyte cross-talk provides new insights on the cellular and molecular mechanisms regulating the cardiac contractile machinery and a novel platform for therapeutically addressable regulators.

Abstract 29: Addition of Galunisertib to DC101 increased angiogenesis inhibition and tumor growth control in hepatocellular carcinoma (HCC)

Introduction: Galunisertib is a selective ATP-mimetic TGF-β receptor (TGFβR)-I inhibitor and DC101 is a rat antagonist antibody to mouse VEGFR-2 and is used to model VEGFR-2 blockade in murine tumor models. Ramucirumab and galunisertib being independently under clinical investigation in HCC patients, our study aimed at exploring the anti-tumoral potency of a combination of galunisertib and DC101 in an in vivo transgenic model of HCC.

Methods: Transgenic mice developing stage-defined HCC were treated for 8 weeks (W) from W8 to W16 with either vehicle, DC101 (40mg/kg, twice weekly, IP), galunisertib (100mg/kg, daily, oral gavage) or DC101 plus galunisertib. Tumor growth was evaluated by ultrasound (liver size) and by the number of macronodules at sacrifice. Angiogenesis was evaluated by doppler (blood flow in the coeliac trunk) and by CD31 staining.

Results: Liver size and the number of liver tumor macronodules were significantly lower in all treatment arms compared to placebo control at both the W12 intermediary sacrifice and W16 final sacrifice; the combination of galunisertib and DC101 showing increased tumor control at W16 (4,43±0,55 mean liver volume (in mm3) in the combination arm vs 5,22±0,86, 5,68±0,78, 7,09±1,54 in the DC101, galunisertib and placebo arms respectively). Angiogenesis assessed by measuring the mean blood flow in the coeliac trunk (TCm), decreased in all treatment arms compared to placebo. At W16, galunisetib potentiated the effect of DC101 with a TCm decrease of 66% compared to 59% and 10% in the DC101 and galunisertib, respectively. These results will be confirmed by the assessment of micronodules number on HPS section for tumor growth and CD31 staining for angiogenesis analysis (number of vessels and the vessel lumen area). The effects of the combination versus monotherapies will be evaluated on the immune landscape.

Conclusion: The combination of galunisertib and DC101 showed promising anti-tumor activities that were associated with decreased angiogenesis.

Citation Format: Annemilai Tijeras-Raballand, Christian Hobeika, Elise Payen, Matthieu Martinet, Philippe Bonnin, Karim A. Benhadji, Clarisse Eveno, Marc Pocard, Sandrine Faivre, Eric Raymond, Armand de Gramont. Addition of Galunisertib to DC101 increased angiogenesis inhibition and tumor growth control in hepatocellular carcinoma (HCC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 29. doi:10.1158/1538-7445.AM2017-29

Abstract 4044: LY3039579, a novel Notch inhibit, potentiates the anti-tumoral effects of sorafenib in hepatocellular carcinoma (HCC)

Introduction: Notch pathway has been involved in cell fate determination, cell differentiation, proliferation and death. Notch promotes cell survival, angiogenesis and treatment resistance in numerous cancers, making it a promising target for cancer therapy. The role of the Notch pathways in HCC tumorigenesis has shown some controversies over time and across studies, being endowed with both oncogenic and tumor suppressive properties. Our study aimed at investigating the anti-tumoral effects of combining LY3039478, a novel Notch inhibitor, to sorafenib in an in vivo transgenic model of HCC.

Methods: Transgenic mice developing stage-defined HCC were treated for 8 weeks (W) from W8 to W16 with either vehicle, LY3039478 (8mg/kg, thrice weekly, oral gavage), sorafenib (30mg/kg, daily, oral gavage) or LY3039478 plus sorafenib. Tumor growth was evaluated by ultrasound (liver size), by the number of macronodules, and the number of micronodules on HPS sections at sacrifice. Angiogenesis was evaluated by doppler (blood flow in the coeliac trunk) and by CD31 staining.

Results: Liver size and the number of liver tumor macronodules were significantly lower in all treatment arms compared to control placebo at both the W12 intermediary sacrifice and W16 final sacrifice; the combination of LY3039478 and sorafenib showing increased tumor control at W16 (4,39±0,82 in mean liver volumes (in mm3) in the combination arm vs 5,41±1,0, 5,84±0,47, 7,09±1,5 in the sorafenib, LY3039478 and placebo arms respectively). Angiogenesis assessed by measuring the mean blood flow in the coeliac trunk (TCm), decreased in all treatment arms, compared to placebo. At W16, LY3039478 potentiated the effect of sorafenib, with a TCm decrease of 36% compared to 23% and18% the sorafenib and LY3039478 arms, respectively. These results will be confirmed by the assessment of micronodules number on HPS section for tumor growth and CD31 staining for angiogenesis analysis (number of vessels and the vessel lumen area). The effects of the combination versus monotherapies will be evaluated on the immune landscape.

Conclusion: The combination of LY3039478 and sorafenib showed promising anti-tumor activities that were associated with decreased angiogenesis.

Citation Format: Annemilai Tijeras-Raballand, Christian Hobeika, Elise Payen, Matthieu Martinet, Philippe Bonnin, Karim A. Benhadji, Bharvin R. Patel, Clarisse Eveno, Marc Pocard, Sandrine Faivre, Eric Raymond, Armand de Gramont. LY3039579, a novel Notch inhibit, potentiates the anti-tumoral effects of sorafenib in hepatocellular carcinoma (HCC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4044. doi:10.1158/1538-7445.AM2017-4044

Extreme-Dipper Profile, Increased Aortic Stiffness, and Impaired Subendocardial Viability in Hypertension

BACKGROUND

In treated hypertensives, extreme-dippers with stable coronary artery disease (CAD) exhibit more severe nighttime cardiac ischemia than dippers. After excluding confounding factors such as diabetes, CAD or chronic kidney disease (CKD), we assessed whether subendocardial viability, determined by the Buckberg index, was more significantly impaired in extreme-dippers than in dippers.

METHODS

Two hundred thirteen consecutive treated hypertensives (156 dippers, 57 extreme-dippers), were included. After 24-hour ambulatory blood pressure (BP) monitoring, patients underwent radial applanation tonometry (with determination of: subendocardial viability ratio [SEVR], central augmentation index [AIx], and pulse pressure amplification [PPamp]), carotid-femoral pulse wave velocity (cfPWV) measurement, and cycle ergometer stress testing.

RESULTS

Extreme-dippers showed higher cfPWV (8.99 ± 2.16 vs. 8.29 ± 1.69 m/s, P = 0.014), higher AIx (29.7 ± 9.4 vs. 26.4 ± 10.4%, P = 0.042), lower PPamp (1.22 ± 0.14 vs. 1.30 ± 0.15, P < 0.001), lower SEVR (146 ± 23% vs. 157 ± 26%, P = 0.007), and lower nighttime diastolic BP (DBP) (70 ± 9 vs. 75 ± 9 mm Hg, P < 0.001) than dippers. SEVR and cfPWV were inversely correlated. Among extreme-dippers, women exhibited lower SEVR (138 ± 21% vs. 161 ± 23%, P = 0.004), PPamp (1.16 ± 0.10 vs. 1.31 ± 0.15, P < 0.001), and nighttime DBP (67 ± 8 mm Hg vs. 72 ± 8 mm Hg, P = 0.017) than men.

CONCLUSIONS

Extreme-dipper treated hypertensives with no history of CAD, diabetes or CKD, present increased aortic stiffness and low PPamp. Furthermore, this is the first demonstration of the greater likelihood of these patients to exhibit impaired subendocardial viability compared to dippers. Extreme-dipper hypertensive patients, women in particular, may have a significantly higher risk of silent myocardial ischemia, thus justifying systematic screening.

Intrapulmonary artery balloon pulsation improves circulatory function after acute myocardial infarction in pigs

AIM

To examine whether pulmonary artery balloon pulsation (PABP) could improve circulatory function in acute myocardial infarction (AMI) in pigs.

METHODS/RESULTS

Ten downsize pigs were sedated and ventilated. AMI was induced by inserting a plug into the left anterior descending artery. A pulsation balloon was placed in the pulmonary artery in all animals. In the treatment group (TG), pulsations began when life-threatening arrhythmia or > 30% drop in mean blood pressure (MBP) or > 40% decrease in cardiac output compared to baseline occurred. Pulsation rate was 120/min, independent of the heartbeat, maintained for 10 min. The control group (CG) received no pulsation. In the TG (n = 5), mean BP after the AMI improved by 7 ± 12 mmHg after 150 min while in the CG, MBP decreased by 17 ± 25 mmHg, P < 0.05; coronary perfusion pressure improved by 8 ± 7 mmHg in the TG but decreased by 15 ± 12 in the CG (P < 0.05). In the CG, cardiac output did not change but in the TG it improved from 3.5 ± 0.9 after the AMI to 4.2 ± 1.1 l/min 150 min after AMI (P < 0.05). The TG required 1.8 ± 0.4 electric shocks for ventricular fibrillation versus 0.8 ± 0.4 in the pulsation group (P < 0.05).

CONCLUSION

PABP could be useful in the management of AMI due to improved mean arterial BP, coronary perfusion pressure, cardiac output and electrical stability. The mechanism of this effect remains to be determined.

Low-pressure sequential compression of lower limbs enhances forearm skin blood flow

Purpose: We investigated whether forearm skin blood flow could be improved when a multilayer pulsatile inflatable suit was applied at a low pressure to the lower limbs and abdomen. We hypothesized that a non-invasive purely mechanical stimulation of the lower limbs could induce remote forearm blood flow modifications. Methods: The pulsatile suit induced a sequential compartmentalized low compression (65 mmHg), which was synchronized with each diastole of the cardiac cycle with each phase evolving centripetally (lower limbs to abdomen). Modifications of the forearm skin blood flow were continuously recorded by laser Doppler flowmetry (LDF) at baseline and during the pulsatile suit application. Endothelium-dependent and endothelium-independent vasodilations of the forearm skin microcirculation were measured by LDF in response to a local transdermal iontophoretic application of acetylcholine (ACh-test) and to hyperthermia (hyperT- test). Results: Twenty-four healthy volunteers, 12 men and 12 women (43±14 years) were included in the study. LDF responses increased 1) under pulsatile suit (97±106%, p