Single-cell profile reveals the landscape of cardiac immunity and identifies a cardio-protective Ym-1hi neutrophil in myocardial ischemia-reperfusion injury.

Myocardial ischemia-reperfusion injury (MIRI) is a major hindrance to the success of cardiac reperfusion therapy. Although increased neutrophil infiltration is a hallmark of MIRI, the subtypes and alterations of neutrophils in this process remain unclear. Here, we performed single-cell sequencing of cardiac CD45+ cells isolated from the murine myocardium subjected to MIRI at six-time points. We identified diverse types of infiltrating immune cells and their dynamic changes during MIRI. Cardiac neutrophils showed the most immediate response and largest changes and featured with functionally heterogeneous subpopulations, including Ccl3hi Neu and Ym-1hi Neu, which were increased at 6 h and 1 d after reperfusion, respectively. Ym-1hi Neu selectively expressed genes with protective effects and was, therefore, identified as a novel specific type of cardiac cell in the injured heart. Further analysis indicated that neutrophils and their subtypes orchestrated subsequent immune responses in the cardiac tissues, especially instructing the response of macrophages. The abundance of Ym-1hi Neu was closely correlated with the therapeutic efficacy of MIRI when neutrophils were specifically targeted by anti-Lymphocyte antigen 6 complex locus G6D (Ly6G) or anti-Intercellular cell adhesion molecule-1 (ICAM-1) neutralizing antibodies. In addition, a neutrophil subtype with the same phenotype as Ym-1hi Neu was detected in clinical samples and correlated with prognosis. Ym-1 inhibition exacerbated myocardial injury, whereas Ym-1 supplementation significantly ameliorated injury in MIRI mice, which was attributed to the tilt of Ym-1 on the polarization of macrophages toward the repair phenotype in myocardial tissue. Overall, our findings reveal the anti-inflammatory phenotype of Ym-1hi Neu and highlight its critical role in myocardial protection during the early stages of MIRI.

Estimated Glucose Disposal Rate Predicts Renal Progression in Type 2 Diabetes Mellitus: A Retrospective Cohort Study.

Context: Insulin resistance is a feature of type 2 diabetes mellitus (T2DM). The estimated glucose disposal rate (eGDR), a validated marker for insulin resistance, is associated with complications of diabetes, but few studies have explored the relationship between eGDR and renal outcomes in T2DM. Objective: This study investigated the value of eGDR in predicting renal progression in T2DM. Methods: A total of 956 T2DM patients with a baseline estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73 m2 and 5 years of follow-up were enrolled. Primary outcomes were rapid eGFR decline, eGFR <60 mL/min/1.73 m2, and composite renal endpoint consisting of 50% eGFR decline, doubling of serum creatinine, or end-stage renal disease. A continuous scale with restricted cubic spline curves and a generalized linear model were applied to evaluate the associations between eGDR and primary outcomes. Results: Rapid eGFR decline was experienced by 23.95% of patients, 21.97% with eGFR <60 mL/min/1.73 m2, and 12.13% with the composite renal endpoint. The eGDR showed a relationship with follow-up eGFR and percentage change in eGFR (P < .001). An eGDR <6.34 mg/kg/min was an independent risk factor for rapid eGFR decline, eGFR < 60 mL/min/1.73 m2, or the composite renal endpoint(P < .05). Compared with eGDR of 5.65∼6.91 mg/kg/min, eGDR levels >8.33 mg/kg/min decreased the risk of rapid eGFR decline by 75%, eGFR < 60 mL/min/1.73 m2 by 60%, and the composite renal endpoint by 61%. Subgroup analysis was performed by sex, age, and diabetes duration, which showed that eGDR was associated with primary outcomes. Conclusion: Lower eGDR is a predictive factor for renal deterioration in T2DM patients.

Blocking VCAM-1 Prevents Angiotensin II-Induced Hypertension and Vascular Remodeling in Mice.

Adhesion of monocytes to the vascular endothelium frequently leads to an inflammatory response, which contributes to hypertension and vascular remodeling. Vascular cellular adhesion molecule-1 (VCAM-1) plays an important role in leukocyte adhesion and migration during inflammatory diseases. However, its role in angiotensin (Ang) II -induced hypertension and vascular dysfunction remains largely unknown. Wild-type (WT) mice were administered a VCAM-1 neutralizing antibody (0.1 or 0.2 mg/mouse/day) or IgG control and then infused with Ang II (490 ng kg-1 min-1) or saline continuously for 14 days. Systolic blood pressure (SBP) was measured with a tail-cuff system, pathological changes in the aorta were assessed by histological staining, and vascular relaxation was analyzed an aortic ring assay. Our results indicated that compared with saline infusion, Ang II infusion significantly upregulated VCAM-1 expression in the mouse aorta and serum. Moreover, Ang II infusion markedly increased arterial hypertension, wall thickness, fibrosis, infiltration of Mac-2+ macrophages, reactive oxygen species (ROS) production and vascular relaxation dysfunction. Conversely, blockade of VCAM-1 with a neutralizing antibody substantially alleviated these effects. In vitro experiments further confirmed that the VCAM-1 neutralizing antibody inhibited Ang II-induced macrophage adhesion and migration and DNA damage and oxidative stress in endothelial cells (ECs). In conclusion, these results indicate that blockade of VCAM-1 exerts a protective effect against Ang II-induced arterial hypertension and dysfunction by regulating monocytes adhesion and infiltration into the endothelium and represents a novel therapeutic approach for hypertension.

Angiotensin II Induces Cardiac Edema and Hypertrophic Remodeling through Lymphatic-Dependent Mechanisms.

Cardiac lymphatic vessel growth (lymphangiogenesis) and integrity play an essential role in maintaining tissue fluid balance. Inhibition of lymphatic lymphangiogenesis is involved in cardiac edema and cardiac remodeling after ischemic injury or pressure overload. However, whether lymphatic vessel integrity is disrupted during angiotensin II- (Ang II-) induced cardiac remodeling remains to be investigated. In this study, cardiac remodeling models were established by Ang II (1000 ng/kg/min) in VEGFR-3 knockdown (Lyve-1Cre VEGFR-3f/-) and wild-type (VEGFR-3f/f) littermates. Our results indicated that Ang II infusion not only induced cardiac lymphangiogenesis and upregulation of VEGF-C and VEGFR-3 expression in the time-dependent manner but also enhanced proteasome activity, MKP5 and VE-cadherin degradation, p38 MAPK activation, and lymphatic vessel hyperpermeability. Moreover, VEGFR-3 knockdown significantly inhibited cardiac lymphangiogenesis in mice, resulting in exacerbation of tissue edema, hypertrophy, fibrosis superoxide production, inflammation, and heart failure (HF). Conversely, administration of epoxomicin (a selective proteasome inhibitor) markedly mitigated Ang II-induced cardiac edema, remodeling, and dysfunction; upregulated MKP5 and VE-cadherin expression; inactivated p38 MAPK; and reduced lymphatic vessel hyperpermeability in WT mice, indicating that inhibition of proteasome activity is required to maintain lymphatic endothelial cell (LEC) integrity. Our results show that both cardiac lymphangiogenesis and lymphatic barrier hyperpermeability are implicated in Ang II-induced adaptive hypertrophic remodeling and dysfunction. Proteasome-mediated hyperpermeability of LEC junctions plays a predominant role in the development of cardiac remodeling. Selective stimulation of lymphangiogenesis or inhibition of proteasome activity may be a potential therapeutic option for treating hypertension-induced cardiac remodeling.