Dapagliflozin Attenuates Myocardial Fibrosis by Inhibiting the TGF-ß1/Smad Signaling Pathway in a Normoglycemic Rabbit Model of Chronic Heart Failure.

Recent studies have shown that sodium-glucose cotransporter-2 (SGLT2) inhibitors play a beneficial role for normoglycemic patients with heart failure (HF). However, the underlying mechanism remains largely unexplored. In the present study, we aimed to investigate the cardioprotective effect of SGLT2 inhibitors in a normoglycemic rabbit model of chronic heart failure (CHF) and its potential mechanism was also explored. A total of 24 male New Zealand white rabbits were randomly divided into the sham group, HF group, perindopril group, and dapagliflozin (DAPA) group. The normoglycemic CHF model was established by aortic constriction for 12 weeks. In the 13th week, DAPA (1 mg/kg/day) or perindopril (0.5 mg/kg/day) was administered by oral gavage daily for 10 weeks. Both the sham group and HF group were given normal saline via gavage. After 10 weeks, the heart structure and function were evaluated by echocardiography and plasma NT-proBNP. Moreover, cardiac fibrosis was analyzed using immunohistochemistry, Masson's trichrome staining, and Western blotting analysis. The results showed that DAPA improved the myocardial structure and function of normoglycemic CHF rabbits and ameliorated myocardial fibrosis. Further study indicated that DAPA suppressed cardiac fibrosis by inhibiting the transforming growth factor ß1 (TGF-ß1)/Smad signaling pathway. Collectively, our findings showed that DAPA could ameliorate cardiac fibrosis in normoglycemic CHF rabbits by inhibiting the TGF-ß1/Smad signaling pathway.

Sacubitril/valsartan inhibits ox­LDL­induced MALAT1 expression, inflammation and apoptosis by suppressing the TLR4/NF­κB signaling pathway in HUVECs.

The therapeutic effect of sacubitril/valsartan (S/V) on heart failure has been confirmed, while its role in atherosclerosis remains largely unexplored. The present study aimed to investigate the effects of S/V on the expression of metastasis­associated lung adenocarcinoma transcript 1 (MALAT1), inflammation and apoptosis in human umbilical vein endothelial cells (HUVECs) induced by oxidized low­density lipoprotein (ox­LDL) and to elucidate its possible mechanism. Cell Counting Kit­8 assay was used to detect cell viability. Reverse transcription­quantitative PCR was performed to detect the MALAT1 expression. ELISA was performed to detect the levels of IL­1ß, IL­6 and TNF­α. Flow cytometry was conducted to detect the apoptotic rate of cells. A nitric oxide (NO) detection kit was used to determine the concentration of NO. Western blotting analysis was performed to determine the levels of intercellular cell adhesion molecule (ICAM)­1, vascular cell adhesion molecule (VCAM)­1, endothelin­1, caspase­3, Bax, Bcl­2, Toll­like receptor 4 (TLR4), p65 and p­p65. Compared with the ox­LDL group, S/V treatment significantly increased the cell viability, NO concentration and Bcl­2 expression, decreased the levels of IL­1ß, IL­6 and TNF­α and reduced the expressions of MALAT1, ICAM­1, VCAM­1, cleaved­caspase­3, Bax, TLR4 and p­p65. Overall, the findings suggested that S/V could downregulate the expression of MALAT1, inhibit inflammation and apoptosis and improve endothelial function in ox­LDL­induced HUVECs via inactivating the TLR4/NF­κB signaling pathway. Therefore, S/V might be utilized as a promising therapeutic strategy for the prevention and treatment of atherosclerosis.

[Interleukin-8 monoclonal antibody attenuates smooth muscle cell proliferation and balloon inflation-induced abdominal aorta stenosis in rabbits].

OBJECTIVE: To observe the effects of interleukin-8 monoclonal antibody on smooth muscle cell proliferation and balloon inflation-induced abdominal aorta stenosis in rabbits. METHODS: Thirty-six New Zealand white rabbits were randomly assigned to balloon inflation group (group A, n = 12), interleukin-8 monoclonal antibody pre-treated rabbits (2 mg/kg for 3 days before balloon inflation, group B, n = 12) and sham-operated control group (group C, n = 12). Peripheral blood was collected before experiment and at 4 h, 1, 3, 7, 14, and 28 days post balloon inflation or sham operation and the levels of IL-8 were measured by enzyme linked immunosorbent assay (ELISA). The ratio of positive and negative masculine cells in the high power microscopic field was determined in proliferating cell nuclear antigen (PCNA) stained slide. Histopathologic examination was performed in abdominal aorta and luminal area, intima and tunica media area were measured. RESULTS: Plasma interleukin-8 began to rise at 4 h and peaked at 1 day and remained increased up to 28 days after balloon inflation in rabbits of group A, plasma interleukin-8 level in group A was significantly higher than in group B and C at 4 h and thereafter post operation. The ratio of positive and negative masculine cells was significantly increased in group A compared to group C and was significantly lower in group B than in group A. Abdominal aorta stenosis, luminal area, intima and tunica media area were significantly reduced in group B than in group A. Correlation analysis indicated that there were positive relations between plasma IL-8 level and intima thickness, area of intima and tunica media, respectively (r = 0.894, 0.783, 0.801, 0.912, all P < 0.01). CONCLUSIONS: Plasma IL-8 level is increased in this abdominal aorta stenosis model and is positively correlated to the severity of abdominal aorta stenosis. IL-8 monoclonal antibody could significantly reduce abdominal aorta stenosis in this abdominal aorta stenosis model.

[Effect of bone mesenchymal stem cells transplantation on malignant ventricular arrhythmia induced byelectrophysiological stimulation in a mini-swine model of acute myocardial infarction].

OBJECTIVE: To investigate the effects of autologous bone mesenchymal stem cells (MSC) transplantation on malignant arrhythmia induced by electrophysiological (EP) stimulation and cardiomyocyte ion channels remodeling in a mini-swine model of acute myocardial infarction (AMI). METHODS: Immediately after AMI (LAD occluded for 120 min), MSC (10 x 10(7), labeled by colloidal gold and co-cultivated with 5-azacytidine, 5-aza, n = 12) or equal volume saline (n = 10) were injected through over-the-wire (OTW) balloon in LAD at distal over D(1). EP stimulation is performed after 2 hours and 4 weeks in both groups to induce arrhythmia. The variance of heterogeneity of sodium currents (I(Na)) and I(Na) steady-state inactivation curves in different zones of infracted wall were investigated by patch clamp technology and the relationship between ionic channel and ventricular arrhythmia is analyzed. RESULTS: EP induced malignant ventricular arrhythmia (VT) rate was similar (MSC 75% vs. saline 90%, P = 0.455) at 2 hours post AMI and was significantly lower in MSC group (25% vs. 80%, P = 0.012) at 4 weeks post AMI. The Peak I(Na) current densities of the Endo, Media and Epi were significantly lower in MSC group [(-14.04 +/- 3.82) pA/pF, (-29.26 +/- 5.70) pA/pF, (-12.43 +/- 3.04) pA/pF] compared those in saline group [(-9.71 +/- 3.38) pA/pF, (-18.98 +/- 4.05) pA/pF, (-8.47 +/- 3.34) pA/pF, all P < 0.05]. The I(Na) steady-state inactivation curves of the Epi, Endo and Media in mini-swine with VT in MSC group [(-126.2 +/- 10.9) mV, (-106.7 +/- 11.9) mV, (-105.4 +/- 11.0) mV] were similar as those in saline group with VT [(-129.1 +/- 10.9) mV, (-112.2 +/- 9.9) mV, (-109.7 +/- 9.2) mV, all P > 0.05] while significantly lower compared to MSC group without VT [(-93.1 +/- 13.8) mV, (-95.2 +/- 15.5) mV, (-103.4 +/- 8.7) mV, all P < 0.05]. The multiple logistic regression analysis showed that I(Na) current density (RR = 1.449, 95% CI 1.276 - 2.079, P = 0.029) and I(Na) steady-state inactivation curves (RR = 1.092, 95% CI 1.008 - 1.917, P = 0.012) were the independent factors for reduced VT. CONCLUSIONS: Autologous MSC attenuated malignant ventricular arrhythmia induced by EP at 4 weeks in mini-swine with AMI which might due to altered cardiomyocyte ion channels remodeling induced by MSC.

Mechanisms of improvement of left ventricle remodeling by trans-planting two kinds of autologous bone marrow stem cells in pigs.

BACKGROUND: The necrosis of a large number of myocardial cells after acute myocardial infarction (AMI) results in a decrease of cardiac function and ventricle remodeling. Stem cell transplantation could improve cardiac function after AMI, but the involving mechanisms have not been completely understood. The present study aimed to investigate the effects of transplantation of autologous bone marrow mononuclear cells (BM-MNC) and mesenchymal stem cells (MSCs) via the coronary artery on the ventricle remodeling after AMI as well as the mechanisms of the effects of transplantation of different stem cells on ventricle remodeling. METHODS: A total of 36 male pigs were enrolled in this study, which were divided into 4 groups: control group, simple infarct model group, BM-MNC transplantation group, and MSCs transplantation group. At 90 minutes when a miniature porcine model with AMI was established, transplantation of autologous BM-MNC ((4.7 +/- 1.7) x 10(7)) and MSCs ((6.2 +/- 1.6) x 10(5)) was performed in the coronary artery via a catheter. Ultrasound, electron microscope, immunohistochemical examination and real time reverse transcriptase-polymerase chain reaction were used respectively to observe cardiac functions, counts of blood vessels of cardiac muscle, cardiac muscle nuclear factor (NF)-kappaB, myocardial cell apoptosis, and the expression of the mRNA of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in cardiac muscles. Multivariate Logistic regression was used to analyze the correlation factors of left ventricular end-diastolic diameter (EDD). RESULTS: The number of blood vessels in the infarct zone and around its border in the BM-MNC transplantation group was more than those in the infarct model group and MSCs group (P = 0.0001) and there was less myocardial cell apoptosis in the stem cell transplantation group than that in the infarct model group (all P < 0.01). The positive rate of NF-kappaB in the stem cell transplantation group was lower than that in the infarct model group (P = 0.001). The gene expression of VEGF in the infarct border zone of the BM-MNC group was higher than that in the MSCs group (P = 0.0001). The gene expression of bFGF in the infarct border zone in the MSCs transplantation group was higher than that in the infarct model group and the BM-MNC group (P = 0.0001). Left ventricular ejection fraction was inversely proportional to the apoptotic rate of myocardial cells and cardiac muscle NF-kappaB but positively correlated with the number of blood vessels and the expression of VEGF and bFGF in the infarct zone and infarct border zone. The Multivariate Logistic regression analysis on the factors influencing the left ventricular end-diastolic diameter after stem cell transplantation showed that the expression of VEGF mRNA in the cardiac muscles in the infarct zone, the number of apoptotic myocardial cells and the expression of NF-kappaB in the infarct border zone were independent factors for predicting the inhibitory effect on the dilation of left ventricular EDD after stem cell transplantation. CONCLUSIONS: Transplantation of autologous BM-MNC and MSCs in pigs can improve the condition of left ventricular remodeling and recover the cardiac functions after AMI. The improvement of cardiac functions is related to the increase of blood vessels, the increased expression of VEGF and bFGF, the reduction of myocardial cell apoptosis, and the decrease of NF-kappaB level in cardiac muscle tissues after stem cell transplantation.