Ezh2 emerges as an epigenetic checkpoint regulator during monocyte differentiation limiting cardiac dysfunction post-MI.

Epigenetic regulation of histone H3K27 methylation has recently emerged as a key step during alternative immunoregulatory M2-like macrophage polarization; known to impact cardiac repair after Myocardial Infarction (MI). We hypothesized that EZH2, responsible for H3K27 methylation, could act as an epigenetic checkpoint regulator during this process. We demonstrate for the first time an ectopic EZH2, and putative, cytoplasmic inactive localization of the epigenetic enzyme, during monocyte differentiation into M2 macrophages in vitro as well as in immunomodulatory cardiac macrophages in vivo in the post-MI acute inflammatory phase. Moreover, we show that pharmacological EZH2 inhibition, with GSK-343, resolves H3K27 methylation of bivalent gene promoters, thus enhancing their expression to promote human monocyte repair functions. In line with this protective effect, GSK-343 treatment accelerated cardiac inflammatory resolution preventing infarct expansion and subsequent cardiac dysfunction in female mice post-MI in vivo. In conclusion, our study reveals that pharmacological epigenetic modulation of cardiac-infiltrating immune cells may hold promise to limit adverse cardiac remodeling after MI.

Regulation and impact of cardiac lymphangiogenesis in pressure-overload-induced heart failure.

AIMS: Lymphatics are essential for cardiac health, and insufficient lymphatic expansion (lymphangiogenesis) contributes to development of heart failure (HF) after myocardial infarction. However, the regulation and impact of lymphangiogenesis in non-ischaemic cardiomyopathy following pressure-overload remains to be determined. Here, we investigated cardiac lymphangiogenesis following transversal aortic constriction (TAC) in C57Bl/6 and Balb/c mice, and in end-stage HF patients. METHODS AND RESULTS: Cardiac function was evaluated by echocardiography, and cardiac hypertrophy, lymphatics, inflammation, oedema, and fibrosis by immunohistochemistry, flow cytometry, microgravimetry, and gene expression analysis. Treatment with neutralizing anti-VEGFR3 antibodies was applied to inhibit cardiac lymphangiogenesis in mice. We found that VEGFR3-signalling was essential to prevent cardiac lymphatic rarefaction after TAC in C57Bl/6 mice. While anti-VEGFR3-induced lymphatic rarefaction did not significantly aggravate myocardial oedema post-TAC, cardiac immune cell levels were increased, notably myeloid cells at 3 weeks and T lymphocytes at 8 weeks. Moreover, whereas inhibition of lymphangiogenesis did not aggravate interstitial fibrosis, it increased perivascular fibrosis and accelerated development of left ventricular (LV) dilation and dysfunction. In clinical HF samples, cardiac lymphatic density tended to increase, although lymphatic sizes decreased, notably in patients with dilated cardiomyopathy. Similarly, comparing C57Bl/6 and Balb/c mice, lymphatic remodelling post-TAC was linked to LV dilation rather than to hypertrophy. The striking lymphangiogenesis in Balb/c was associated with reduced cardiac levels of macrophages, B cells, and perivascular fibrosis at 8 weeks post-TAC, as compared with C57Bl/6 mice that displayed weak lymphangiogenesis. Surprisingly, however, it did not suffice to resolve myocardial oedema, nor prevent HF development. CONCLUSIONS: We demonstrate for the first time that endogenous lymphangiogenesis limits TAC-induced cardiac inflammation and perivascular fibrosis, delaying HF development in C57Bl/6 but not in Balb/c mice. While the functional impact of lymphatic remodelling remains to be determined in HF patients, our findings suggest that under settings of pressure-overload poor cardiac lymphangiogenesis may accelerate HF development.

CRISPR/Cas9-mediated inactivation of the phosphatase activity of soluble epoxide hydrolase prevents obesity and cardiac ischemic injury.

INTRODUCTION: Although the physiological role of the C-terminal hydrolase domain of the soluble epoxide hydrolase (sEH-H) is well investigated, the function of its N-terminal phosphatase activity (sEH-P) remains unknown. OBJECTIVES: This study aimed to assess in vivo the physiological role of sEH-P. METHODS: CRISPR/Cas9 was used to generate a novel knock-in (KI) rat line lacking the sEH-P activity. RESULTS: The sEH-P KI rats has a decreased metabolism of lysophosphatidic acids to monoacyglycerols. KI rats grew almost normally but with less weight and fat mass gain while insulin sensitivity was increased compared to wild-type rats. This lean phenotype was more marked in males than in female KI rats and mainly due to decreased food consumption and enhanced energy expenditure. In fact, sEH-P KI rats had an increased lipolysis allowing to supply fatty acids as fuel to potentiate brown adipose thermogenesis under resting condition and upon cold exposure. The potentiation of thermogenesis was abolished when blocking PPARγ, a nuclear receptor activated by intracellular lysophosphatidic acids, but also when inhibiting simultaneously sEH-H, showing a functional interaction between the two domains. Furthermore, sEH-P KI rats fed a high-fat diet did not gain as much weight as the wild-type rats, did not have increased fat mass and did not develop insulin resistance or hepatic steatosis. In addition, sEH-P KI rats exhibited enhanced basal cardiac mitochondrial activity associated with an enhanced left ventricular contractility and were protected against cardiac ischemia-reperfusion injury. CONCLUSION: Our study reveals that sEH-P is a key player in energy and fat metabolism and contributes together with sEH-H to the regulation of cardiometabolic homeostasis. The development of pharmacological inhibitors of sEH-P appears of crucial importance to evaluate the interest of this promising therapeutic strategy in the management of obesity and cardiac ischemic complications.

A Supraceliac Aortic Cross Clamping Model to Explore Remote Lung Injury and the Endothelial Glycocalyx.

BACKGROUND: We hypothesized that supraceliac aortic cross clamping could induce lung injury mediated by an inflammatory ischemia-reperfusion (IR) trigger. We aimed to characterize glycocalyx (GCX), a component of endothelial membrane, participating to remote lung injury. METHODS: Rats underwent supraceliac aortic cross clamping for 40 min and were sacrificed at 0, 3, 6, and 24 hr of reperfusion (n = 10/group). Each group was compared to sham (n = 6/group). GCX products (syndecan-1 [Sdc-1] and heparan sulfate [HS]), tumor necrosis factor-alpha (TNF-α), and interleukin-1ß (IL-1ß) were measured in plasma (enzyme-linked immunosorbent assay[ELISA]). Lungs were harvested for measurements of TNF-α, IL-1ß (polymerase chain reaction) and Sdc-1 (western blotting [WB]). Histologic lung injury scoring and pulmonary gravimetry were analyzed in a blinded manner. RESULTS: Plasmatic Sdc-1, HS, TNF-α, and IL-1ß reached peak levels at 3 hr. Levels were significantly higher in clamping groups than sham at 6 hr for Sdc-1, at 0 and 3 hr for HS, at 3 and 6 hr for TNF-α, and at 3 hr for IL-1ß. Lung TNF-α and Interleukin-1ß reached peak levels at 6 hr. Levels were significantly higher than sham at 6 and 24 hr for TNF-α and at 6 hr for IL-1ß. Lung Sdc-1 was lowest at 3 hr. Sdc-1 was not significantly different compared to sham at the different reperfusion times. At 3 hr, it was 0.27 ± 0.03 vs. 0.33 ± 0.02 (sham) (P = 0.09). Histopathologic scores at 6 and 24 hr were higher in clamping groups than sham. At 6 and 24 hr, it was higher for hemorrhage, polynuclear neutrophil (PNN) infiltration and intravascular leukocytes. Pulmonary edema was higher by gravimetry at 0 and 6 hr. CONCLUSIONS: Supra celiac aortic clamping causes early lung injury in relation with a systemic inflammatory response associated with altered GCX structure.

Endothelium-Specific Deficiency of Polycystin-1 Promotes Hypertension and Cardiovascular Disorders.

BACKGROUND: Autosomal dominant polycystic kidney disease is the most frequent hereditary kidney disease and is generally due to mutations in PKD1 and PKD2, encoding polycystins 1 and 2. In autosomal dominant polycystic kidney disease, hypertension and cardiovascular disorders are highly prevalent, but their mechanisms are partially understood. METHODS: Since endothelial cells express the polycystin complex, where it plays a central role in the mechanotransduction of blood flow, we generated a murine model with inducible deletion of Pkd1 in endothelial cells (Cdh5-CreERT2;Pkd1fl/fl) to specifically determine the role of endothelial polycystin-1 in autosomal dominant polycystic kidney disease. RESULTS: Endothelial deletion of Pkd1 induced endothelial dysfunction, as demonstrated by impaired flow-mediated dilatation of resistance arteries and impaired relaxation to acetylcholine, increased blood pressure and prevented the normal development of arteriovenous fistula. In experimental chronic kidney disease induced by subtotal nephrectomy, endothelial deletion of Pkd1 further aggravated endothelial dysfunction, vascular remodeling, and heart hypertrophy. CONCLUSIONS: Altogether, this study provides the first in vivo demonstration that specific deletion of Pkd1 in endothelial cells promotes endothelial dysfunction and hypertension, impairs arteriovenous fistula development, and potentiates the cardiovascular alterations associated with chronic kidney disease.

Soluble RAGE as a Prognostic Marker of Worsening in Patients Admitted to the ICU for COVID-19 Pneumonia: A Prospective Cohort Study.

Background: The different waves of SARS-CoV-2 infection have strained hospital resources and, notably, intensive care units (ICUs). Identifying patients at risk of developing a critical condition is essential to correctly refer patients to the appropriate structure and to spare limited resources. The soluble form of RAGE (sRAGE), the endoplasmic stress response and its surrogates, GRP78 and VEGF-A, may be interesting markers. Methods: This was a prospective monocenter cohort study of adult patients admitted to the ICU for severe COVID-19 pneumonia. The plasma levels of sRAGE, GRP78 and VEGF-A were measured within the first 24 h. Patients were classified as critical if they further needed vasopressor therapy, renal replacement therapy, or invasive mechanical ventilation, or died during their ICU stay, and were otherwise classified as not critical. Results: A total of 98 patients were included and 39 developed a critical condition. Critical patients presented higher sRAGE (626 [450−1043] vs. 227 [137−404] pg/mL, p < 0.0001), interleukin-6 (43 [15−112] vs. 11 [5−20] pg/mL, p < 0.0001), troponin T (17 [9−39] vs. 10 [6−18] pg/mL, p = 0.003) and NT-pro-BNP (321 [118−446] vs. 169 [63−366] pg/mL, p = 0.009) plasma levels. No difference was observed for VEGF-A and GRP78. The variables independently associated with worsening in the ICU were sRAGE (1.03 [1.01−1.05] per 10 pg/mL) and age (1.7 [1.2−2.4] per 5 years). An sRAGE value of 449.5 pg/mL predicted worsening with a sensitivity of 77% and a specificity of 80%. Conclusion: sRAGE may allow the identification of patients at risk of developing a critical form of COVID-19 pneumonia, and thus may be useful to correctly refer patients to the appropriate structure of care.

Priming of Cardiopulmonary Bypass with Human Albumin Decreases Endothelial Dysfunction after Pulmonary Ischemia-Reperfusion in an Animal Model.

The routine use of mechanical circulatory support during lung transplantation (LTx) is still controversial. The use of prophylactic human albumin (HA) or hypertonic sodium lactate (HSL) prime in mechanical circulatory support during LTx could prevent ischemia−reperfusion (IR) injuries and pulmonary endothelial dysfunction and thus prevent the development of pulmonary graft dysfunction. The objective was to investigate the impact of cardiopulmonary bypass (CPB) priming with HA and HSL compared to a CPB prime with Gelofusine (GF) on pulmonary endothelial dysfunction in a lung IR rat model. Rats were assigned to four groups: IR-CPB-GF group, IR-CPB-HA group, IR-CPB-HSL group and a sham group. The study of pulmonary vascular reactivity by wire myograph was the primary outcome. Glycocalyx degradation (syndecan-1 and heparan) was also assessed by ELISA and electron microscopy, systemic and pulmonary inflammation by ELISA (IL-1ß, IL-10, and TNF-α) and immunohistochemistry. Clinical parameters were evaluated. We employed a CPB model with three different primings, permitting femoral−femoral assistance with left pulmonary hilum ischemia for IR. Pulmonary endothelium-dependent relaxation to acetylcholine was significantly decreased in the IR-CPB-GF group (11.9 ± 6.2%) compared to the IR-CPB-HA group (52.8 ± 5.2%, p < 0.0001), the IR-CPB-HSL group (57.7 ± 6.3%, p < 0.0001) and the sham group (80.8 ± 6.5%, p < 0.0001). We did not observe any difference between the groups concerning glycocalyx degradation, and systemic or tissular inflammation. The IR-CPB-HSL group needed more vascular filling and developed significantly more pulmonary edema than the IR-CPB-GF group and the IR-CPB-HA group. Using HA as a prime in CPB during Ltx could decrease pulmonary endothelial dysfunction's IR-mediated effects. No effects of HA were found on inflammation.

Transient heart rate reduction improves acute decompensated heart failure-induced left ventricular and coronary dysfunction.

AIMS: Acute decompensated heart failure (ADHF), a live-threatening complication of heart failure (HF), associates a further decrease of the already by HF-impaired cardiac function with an increase in heart rate. We evaluated, using a new model of ADHF, whether heart rate reduction (HRR) opposes the acute decompensation-related aggravation of cardiovascular dysfunction. METHODS AND RESULTS: Cardiac output (echocardiography), cardiac tissue perfusion (magnetic resonance imaging), pulmonary wet weight, and in vitro coronary artery relaxation (Mulvany) were assessed 1 and 14 days after acute decompensation induced by salt-loading (1.8 g/kg, PO) in rats with well-established HF due to coronary ligation. HRR was induced by administration of the If current inhibitor S38844, 12 mg/kg PO twice daily for 2.5 days initiated 12 h or 6 days after salt-loading (early or delayed treatment, respectively). After 24 h, salt-loading resulted in acute decompensation, characterized by a reduction in cardiac output (HF: 130 ± 5 mL/min, ADHF: 105 ±  8 mL/min; P < 0.01), associated with a decreased myocardial perfusion (HF: 6.41 ± 0.53 mL/min/g, ADHF: 4.20 ± 0.11 mL/min/g; P < 0.01), a slight increase in pulmonary weight (HF: 1.68 ± 0.09 g, ADHF: 1.81 ± 0.15 g), and impaired coronary relaxation (HF: 55 ± 1% of pre-contraction at acetylcholine 4.5 10-5  M, ADHF: 27 ± 7 %; P < 0.01). Fourteen days after salt-loading, cardiac output only partially recovered (117 ± 5 mL/min; P < 0.05), while myocardial tissue perfusion (4.51 ± 0.44 mL/min; P < 0.01) and coronary relaxation (28 ± 4%; P < 0.01) remained impaired, but pulmonary weight further increased (2.06 ± 0.15 g, P < 0.05). Compared with untreated ADHF, HRR induced by S38844 improved cardiac output (125 ± 1 mL/min; P < 0.05), myocardial tissue perfusion (6.46 ± 0.42 mL/min/g; P < 0.01), and coronary relaxation (79 ± 2%; P < 0.01) as soon as 12 h after S38844 administration. These effects persisted beyond S38844 administration, illustrated by the improvements in cardiac output (130 ± 6 mL/min; P < 0.05), myocardial tissue perfusion (6.38 ± 0.48 mL/min/g; P < 0.01), and coronary relaxation (71 ± 4%; P < 0.01) at Day 14. S38844 did not modify pulmonary weight at Day 1 (1.78 ± 0.04 g) but tended to decrease pulmonary weight at Day 14 (1.80 ± 0.18 g). While delayed HRR induced by S38844 never improved cardiac function, early HRR rendered less prone to a second acute decompensation. CONCLUSIONS: In a model mimicking human ADHF, early, but not delayed, transient HRR induced by the If current inhibitor S38844 opposes acute decompensation by preventing the decompensated-related aggravation of cardiovascular dysfunction as well as the development of pulmonary congestion, and these protective effects persist beyond the transient treatment. Whether early transient HRR induced by If current inhibitors or other bradycardic agents, i.e. beta-blockers, exerts beneficial effects in human ADHF warrants further investigation.

Cardiopulmonary bypass increases endothelial dysfunction after pulmonary ischaemia-reperfusion in an animal model.

OBJECTIVES: Endothelial dysfunction during ischaemia-reperfusion (IR) is a major cause of primary graft dysfunction during lung transplantation. The routine use of cardiopulmonary bypass (CPB) during lung transplantation remains controversial. However, the contribution of CPB to pulmonary endothelial dysfunction remains unclear. The objective was to investigate the impact of CPB on endothelial dysfunction in a lung IR rat model. METHODS: Rats were allocated to 4 groups: (i) Sham, (ii) IR, (iii) CPB and (iv) IR-CPB. The primary outcome was the study of pulmonary vascular reactivity by wire myograph. We also assessed glycocalyx degradation by enzyme-linked immunosorbent assay and electron microscopy and both systemic and pulmonary inflammation by enzyme-linked immunosorbent assay and immunohistochemistry. Rats were exposed to 45 min of CPB and IR. We used a CPB model allowing femoro-femoral support with left pulmonary hilum ischaemia for IR. RESULTS: Pulmonary endothelium-dependent relaxation to acetylcholine was markedly reduced in the IR-CPB group (10.7 ± 9.1%) compared to the IR group (50.5 ± 5.2%, P < 0.001), the CPB group (54.1 ± 4.7%, P < 0.001) and the sham group (80.8 ± 6.7%, P < 0.001), suggesting that the association of pulmonary IR and CPB increases endothelial dysfunction. In IR-CPB, IR and CPB groups, vasorelaxation was completely abolished when inhibiting nitric oxide synthase, suggesting that this relaxation process was mainly mediated by nitric oxide. We observed higher syndecan-1 plasma levels in the IR-CPB group in comparison with the other groups, reflecting an increased degradation of glycocalyx. We also observed higher systemic inflammation in the IR-CPB group as shown by the increased plasma levels of IL-1ß, IL-10. CONCLUSIONS: CPB significantly increased the IR-mediated effects on pulmonary endothelial dysfunction. Therefore, the use of CPB during lung transplantation could be deleterious, by increasing endothelial dysfunction.

Short-and long-term administration of imeglimin counters cardiorenal dysfunction in a rat model of metabolic syndrome.

INTRODUCTION: Imeglimin, a glucose-lowering agent targeting mitochondrial bioenergetics, decreases reactive oxygen species (ROS) overproduction and improves glucose homeostasis. We investigated whether this is associated with protective effects on metabolic syndrome-related left ventricular (LV) and vascular dysfunctions. METHODS: We used Zucker fa/fa rats to assess the effects on LV function, LV tissue perfusion, LV oxidative stress and vascular function induced by imeglimin administered orally for 9 or 90 days at a dose of 150 mg/kg twice daily. RESULTS: Compared to untreated animals, 9- and 90-day imeglimin treatment decreased LV end-diastolic pressure and LV end-diastolic pressure-volume relation, increased LV tissue perfusion and decreased LV ROS production. Simultaneously, imeglimin restored acetylcholine-mediated coronary relaxation and mesenteric flow-mediated dilation. One hour after imeglimin administration, when glucose plasma levels were not yet modified, imeglimin reduced LV mitochondrial ROS production and improved LV function. Ninety-day imeglimin treatment reduced related LV and kidney fibrosis and improved kidney function. CONCLUSION: In a rat model, mimicking Human metabolic syndrome, imeglimin immediately countered metabolic syndrome-related cardiac diastolic and vascular dysfunction by reducing oxidative stress/increased NO bioavailability and improving myocardial perfusion and after 90-day treatment myocardial and kidney structure, effects that are, at least in part, independent from glucose control.

Lymphatic and Immune Cell Cross-Talk Regulates Cardiac Recovery After Experimental Myocardial Infarction.

OBJECTIVE: Lymphatics play an essential pathophysiological role in promoting fluid and immune cell tissue clearance. Conversely, immune cells may influence lymphatic function and remodeling. Recently, cardiac lymphangiogenesis has been proposed as a therapeutic target to prevent heart failure after myocardial infarction (MI). We investigated the effects of gene therapy to modulate cardiac lymphangiogenesis post-MI in rodents. Second, we determined the impact of cardiac-infiltrating T cells on lymphatic remodeling in the heart. Approach and Results: Comparing adenoviral versus adeno-associated viral gene delivery in mice, we found that only sustained VEGF (vascular endothelial growth factor)-CC156S therapy, achieved by adeno-associated viral vectors, increased cardiac lymphangiogenesis, and led to reduced cardiac inflammation and dysfunction by 3 weeks post-MI. Conversely, inhibition of VEGF-C/-D signaling, through adeno-associated viral delivery of soluble VEGFR3 (vascular endothelial growth factor receptor 3), limited infarct lymphangiogenesis. Unexpectedly, this treatment improved cardiac function post-MI in both mice and rats, linked to reduced infarct thinning due to acute suppression of T-cell infiltration. Finally, using pharmacological, genetic, and antibody-mediated prevention of cardiac T-cell recruitment in mice, we discovered that both CD4+ and CD8+ T cells potently suppress, in part through interferon-γ, cardiac lymphangiogenesis post-MI. CONCLUSIONS: We show that resolution of cardiac inflammation after MI may be accelerated by therapeutic lymphangiogenesis based on adeno-associated viral gene delivery of VEGF-CC156S. Conversely, our work uncovers a major negative role of cardiac-recruited T cells on lymphatic remodeling. Our results give new insight into the interconnection between immune cells and lymphatics in orchestration of cardiac repair after injury.

Gene Expression of Protein Tyrosine Phosphatase 1B and Endoplasmic Reticulum Stress During Septic Shock.

Introduction: Protein Tyrosine Phosphatase 1B (PTP1B) and endoplasmic reticulum stress (ERS) are involved in the septic inflammatory response. Their inhibition is associated with improved survival in murine models of sepsis. The objective was to describe PTP1B and ERS expression during septic shock in human. Material and Methods: Prospective study including patients admitted to intensive care unit (ICU) for septic shock. Blood samples were collected on days 1 (D1), 3 and 5 (D5). Quantitative PCR (performed from whole blood) evaluated the expression of genes coding for PTP1B (PTPN1) and key elements of ERS (GRP78, ATF6, CHOP) or for endothelial dysfunction-related markers (ICAM1 and ET1). We analyzed gene variation between D5 and D1, collected glycemic parameters, insulin resistance and organ failure was evaluated by Sequential Organ Failure Assessment (SOFA) score. Results: We included 44 patients with a mean SAPS II 50 ± 16 and a mortality rate of 13.6%. Between D1 and D5, there was a significant decrease of PTPN1 (p < 0.001) and ATF6 (p < 0.001) expressions. Their variations of expression were correlated with SOFA variation (PTPN1, r = 0.35, CI 95% [0.05; 0.54], p = 0.03 and ATF6, r = 0.45 CI 95% [0.20; 0.65], p < 0.001). We did not find any correlation between PTPN1 expression and insulin resistance or glycemic parameters. Between D1 and D5, ATF6 and PTPN1 expressions were correlated with that of ET1. Conclusions: Our study has evaluated for the first time the expression of PTP1B and ERS in patients with septic shock, revealing that gene expression variation of PTPN1 and ATF6 are partly correlated with the evolution of septic organ failure and with endothelial dysfunction markers expression.

Altered bioavailability of epoxyeicosatrienoic acids is associated with conduit artery endothelial dysfunction in type 2 diabetic patients.

BACKGROUND: This pathophysiological study addressed the hypothesis that soluble epoxide hydrolase (sEH), which metabolizes the vasodilator and anti-inflammatory epoxyeicosatrienoic acids (EETs) to dihydroxyeicosatrienoic acids (DHETs), contributes to conduit artery endothelial dysfunction in type 2 diabetes. METHODS AND RESULTS: Radial artery endothelium-dependent flow-mediated dilatation in response to hand skin heating was reduced in essential hypertensive patients (n = 9) and type 2 diabetic subjects with (n = 19) or without hypertension (n = 10) compared to healthy subjects (n = 36), taking into consideration cardiovascular risk factors, flow stimulus and endothelium-independent dilatation to glyceryl trinitrate. Diabetic patients but not non-diabetic hypertensive subjects displayed elevated whole blood reactive oxygen species levels and loss of NO release during heating, assessed by measuring local plasma nitrite variation. Moreover, plasma levels of EET regioisomers increased during heating in healthy subjects, did not change in hypertensive patients and decreased in diabetic patients. Correlation analysis showed in the overall population that the less NO and EETs bioavailability increases during heating, the more flow-mediated dilatation is reduced. The expression and activity of sEH, measured in isolated peripheral blood mononuclear cells, was elevated in diabetic but not hypertensive patients, leading to increased EETs conversion to DHETs. Finally, hyperglycemic and hyperinsulinemic euglycemic clamps induced a decrease in flow-mediated dilatation in healthy subjects and this was associated with an altered EETs release during heating. CONCLUSIONS: These results demonstrate that an increased EETs degradation by sEH and altered NO bioavailability are associated with conduit artery endothelial dysfunction in type 2 diabetic patients independently from their hypertensive status. The hyperinsulinemic and hyperglycemic state in these patients may contribute to these alterations. Trial registration NCT02311075. Registered December 8, 2014.

Protein tyrosine phosphatase 1B regulates endothelial endoplasmic reticulum stress; role in endothelial dysfunction.

Protein tyrosine phosphatase 1B (PTP1B) impairs nitric oxide (NO) production and induces endothelial dysfunction in various diseases, including diabetes, septic shock and heart failure. In non-cardiovascular tissues, PTP1B modulates endoplasmic reticulum stress (ERS) however this role has never been assessed in endothelial cells. We evaluated the link between PTP1B, ERS and endothelial dysfunction in mice. Induction of ERS (Tunicamycin) in vivo in mice or ex vivo in mouse arteries led to severe arterial endothelial dysfunction (i.e. reduced flow-dependent, NO mediated dilatation in isolated small mesenteric arteries), and this was prevented by the PTP1B inhibitor trodusquemine and absent in PTP1B-/- mice. Trodusquemine also prevented the Tunicamycin -induced increased arterial levels of the molecular ERS actors 78 kDa glucose-regulated protein (GRP78) and Activating Transcription Factor 6 (ATF6α). Tunicamycin strongly increased the interactions of PTP1B with GRP78 and the activated forms of protein kinase RNA-like endoplasmic reticulum kinase (PERK) and IRE1α (proximity Ligation Assay). Thus, PTP1B plays a central role in the regulation of ERS in the endothelium, and the endothelial protective effect of PTP1B inhibition appears likely due at least in part to reduction of endothelial ERS, notably by promoting PERK protective pathway. Modulation of ER stress via PTP1B inhibitors may be a promising approach to protect the endothelium in cardiovascular diseases.

Short- and long-term administration of the non-steroidal mineralocorticoid receptor antagonist finerenone opposes metabolic syndrome-related cardio-renal dysfunction.

AIM: To determine whether non-steroidal mineralocorticoid receptor (MR) antagonists oppose metabolic syndrome-related end-organ, i.e. cardiac, damage. MATERIALS AND METHODS: In Zucker fa/fa rats, a rat model of metabolic syndrome, we assessed the effects of the non-steroidal MR antagonist finerenone (oral 2 mg/kg/day) on left ventricular (LV) function, haemodynamics and remodelling (using echocardiography, magnetic resonance imaging and biochemical methods). RESULTS: Long-term (90 days) finerenone modified neither systolic blood pressure nor heart rate, but reduced LV end-diastolic pressure and LV end-diastolic pressure-volume relationship, without modifying LV end-systolic pressure and LV end-systolic pressure-volume relationship. Simultaneously, long-term finerenone reduced both LV systolic and diastolic diameters, associated with reductions in LV weight and LV collagen density, while proteinuria and renal nGAL expression were reduced. Short-term (7 days) finerenone improved LV haemodynamics and reduced LV systolic diameter, without modifying LV diastolic diameter. Moreover, short-term finerenone increased myocardial tissue perfusion and reduced myocardial reactive oxygen species, while plasma nitrite levels, an indicator of nitric oxide (NO) bio-availability, were increased. CONCLUSIONS: In rats with metabolic syndrome, the non-steroidal MR antagonist finerenone opposed metabolic syndrome-related diastolic cardiac dysfunction and nephropathy. This involved acute effects, such as improved myocardial perfusion, reduced oxidative stress/increased NO bioavailability, as well as long-term effects, such as modifications in the myocardial structure.

A 30-Minute Supraceliac Aortic Clamping in the Rat Causes Death Due to an Inflammatory Response and Pulmonary Lesions.

BACKGROUND: The treatment of thoracoabdominal aortic aneurysms through an open approach has general and pulmonary consequences of multiple etiologies. Our assumption was that the supraceliac aortic clamping needed for this operation causes a systemic inflammatory response associated with a pulmonary attack. METHODS: We developed a model of 30-min supraceliac aortic clamping in Wistar rats weighing 300 g. After 90 min of reperfusion, the rats were sacrificed. The effects on the digestive tract wall were analyzed by measurement of the mucosal thickness/total thickness ratio. The effects on the mesenteric endothelial function were determined by an ex situ measurement of the arterial pressure/volume curves (third branch). The systemic consequences of the procedure were analyzed by dosing tumor necrosis factor alpha (TNFα), interleukin (IL)1ß, and IL10 in the blood. The pulmonary consequences were analyzed by the measurement of macrophages, polymorphonuclear neutrophils (PNs), T lymphocyte infiltration, pulmonary apoptosis (TUNEL) and active caspase 3. The experimental scheme included 20 rats with ischemia-reperfusion (IR) and 20 control rats. An analysis of survival was carried out on 20 other rats (10 IR and 10 controls). RESULTS: The results were expressed as average ± standard error of the mean. The statistical tests were Student's t-test and Mann-Whitney test. This visceral IR model decreased the ratio of the thickness of the intestinal mucosa compared with that of the control rats (0.77 ± 0.008 vs. 0.82 ± 0.009 [P < 0.001]). This local effect was not accompanied by any mesenteric endothelial dysfunction (P = 0.91). On a systemic level, IR increased TNFα (37.9 ± 1.5 vs. 28.2 ± 0.6 pg/mL; P < 0.0001), IL1ß (67.1 ± 9.8 vs. 22.5 ± 5.6 pg/mL; P < 0.001), and IL10 (753.3 ± 96 vs. 3.7 ± 1.7 pg/mL; P < 0.0001). As regards the lungs, IR increased the parenchymal cellular infiltration by macrophages (6.8 ± 0.8 vs. 4.5 ± 0.4 cells per field; P < 0.05) and PNs (7.4 ± 0.5 vs. 6.2 ± 03 cells per field; P < 0.05). There was no increase in the pulmonary cellular apoptosis measured by TUNEL (P = 0.77) or in the caspase 3 activity (P = 0.59). The mortality of the visceral IR rats was 100% at 36 hr vs. 0% in the animals without IR. CONCLUSIONS: This work showed that the inflammatory response to visceral IR had systemic and pulmonary effects which always results in the death in the rat.

Reduced Insulin Resistance Contributes to the Beneficial Effect of Protein Tyrosine Phosphatase-1B Deletion in a Mouse Model of Sepsis.

Hyperglycemia is a common feature of septic patients and has been associated with poor outcome and high mortality. In contrast, insulin has been shown to decrease mortality and to prevent the incidence of multiorgan failure but is often associated with deleterious hypoglycemia. Protein Tyrosine Phosphatase 1B (PTP1B) is a negative regulator of both insulin signaling and NO production, and has been shown to be an aggravating factor in septic shock. To evaluate the potential therapeutic effect of PTP1B blockade on glucose metabolism and insulin resistance in an experimental model of sepsis, we assessed the effect of PTP1B gene deletion in a cecal ligation and puncture (CLP) model of sepsis. PTP1B gene deletion significantly limited CLP-induced insulin resistance, improved AMP-activated protein kinase signaling pathway and Glucose Transporter 4 translocation, and decreased inflammation. These effects were associated with a reduction of sepsis-induced endothelial dysfunction/impaired NO production and especially of insulin-mediated dilatation. This modulation of insulin resistance may contribute to the beneficial effect of PTP1B blockade in septic shock, especially in terms of inflammation and cardiac metabolism.

The IL-1ß Antibody Gevokizumab Limits Cardiac Remodeling and Coronary Dysfunction in Rats With Heart Failure.

This study reports preclinical data showing that the interleukin (IL)-1ß modulation is a new promising target in the pathophysiological context of heart failure. Indeed, in nondiabetic Wistar and diabetic Goto-Kakizaki rats with chronic heart failure induced by myocardial infarction, administration of the IL-1ß antibody gevokizumab improves 'surrogate' markers of survival (i.e., left ventricular remodeling, hemodynamics, and function as well as coronary function). However, whether IL-1ß modulation per se or in combination with standard treatments of heart failure improves long-term outcome in human heart failure remains to be determined.

Impact of soluble epoxide hydrolase inhibition on early kidney damage in hyperglycemic overweight mice.

This study addressed the hypothesis that inhibition of the EETs degrading enzyme soluble epoxide hydrolase affords renal protection in the early stage of diabetic nephropathy. The renal effects of the sEH inhibitor t-AUCB (10mg/l in drinking water) were compared to those of the sulfonylurea glibenclamide (80mg/l), both administered for 8 weeks in FVB mice subjected to a high-fat diet (HFD, 60% fat) for 16 weeks. Mice on control chow diet (10% fat) and non-treated HFD mice served as controls. Compared with non-treated HFD mice, HFD mice treated with t-AUCB had a decreased EET degradation, as shown by their higher plasma EETs-to-DHETs ratio, and an increased EET production, as shown by the increase in EETs+DHETs levels, which was associated with induction of CYP450 epoxygenase expression. Both agents similarly reduced fasting glycemia but only t-AUCB prevented the increase in the urinary albumine-to-creatinine ratio in HFD mice. Histopathological analysis showed that t-AUCB reduced renal inflammation, which was associated with an increased mRNA expression of the NFκB inhibitor Iκ≡ and related decrease in MCP-1, COX2 and VCAM-1 expressions. Finally, there was a marginally significant increase in reactive oxygen species production in HFD mice, together with an enhanced NOX2 expression. Both agents did not modify these parameters but t-AUCB increased the expression of the antioxidant enzyme superoxide dismutase 1. These results demonstrate that, independently from its glucose-lowering effect, sEH inhibition prevents microalbuminuria and renal inflammation in overweight hyperglycemic mice, suggesting that this pharmacological strategy could be useful in the management of diabetic nephropathy.

Polycystin deficiency induces dopamine-reversible alterations in flow-mediated dilatation and vascular nitric oxide release in humans.

Autosomal dominant polycystic kidney disease (ADPKD) is a renal hereditary disorder associated with increased cardiovascular mortality, due to mutations in polycystin-1 and polycystin-2 genes. Endothelial polycystin-deficient cells have an altered mechanosensitivity to fluid shear stress and subsequent deficit in calcium-induced nitric oxide release, prevented by dopamine receptor stimulation. However, the impact of polycystin deficiency on endothelial function in ADPKD patients is still largely unknown. Here we assessed endothelium-dependent flow-mediated dilatation in 21 normotensive ADPKD patients and 21 healthy control subjects, during sustained (hand skin heating) and transient (postischemic hyperemia) flow stimulation. Flow-mediated dilatation was less marked in ADPKD patients than in controls during heating, but it was similar during postischemic hyperemia. There was no difference in endothelium-independent dilatation in response to glyceryl trinitrate. Local plasma nitrite, an indicator of nitric oxide availability, increased during heating in controls but not in patients. Brachial infusion of dopamine in a subset of ADPKD patients stimulated plasma nitrite increase during heating and improved flow-mediated dilatation. Thus, ADPKD patients display a loss of nitric oxide release and an associated reduction in endothelium-dependent dilatation of conduit arteries during sustained blood flow increase. The correction of these anomalies by dopamine suggests future therapeutic strategies that could reduce the occurrence of cardiovascular events in ADPKD.