Early use of PCSK9 inhibitors in the prognosis of patients with acute coronary syndrome by protecting vascular endothelial function.

INTRODUCTION: Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) has a protective effect on acute coronary syndrome (ACS). However, most studies have shown that this protective effect is based on a decrease in low-density lipoprotein cholesterol (LDL-C), while other mechanisms remain limited. This study aimed to determine whether PCSK9i can improve the prognosis of ACS patients by protecting endothelial function. METHODS: A total of 113 ACS patients were enrolled and randomly assigned to PCSK9i group (PCSK9i combined with statins) and control group (statins only). Blood lipids and endothelial function indicators were measured and analyzed 6 weeks before and after treatment. The effect of PCSK9i on the expression and secretion of endothelial function indicators in vascular endothelial cells were studied by cell experiments. RESULTS: After 6 weeks of treatment, endothelial function indicators such as NO, TM, ICAM-1, ET-1, and flow-mediated vasodilation (FMD) were significantly improved in PCSK9i group compared with control group. Only the changes of NO and vWF were associated with blood lipid levels, whereas the changes of other endothelial function indicators were not significantly associated with blood lipid levels. PCSK9i reduced the incidence of MACEs in patients with ACS compared to those in the control group. In cell experiments, PCSK9i treatment significantly ameliorated LPS induced endothelial injury in HUVECs. CONCLUSION: PCSK9i can protect vascular endothelial function partly independently of its lipid-lowering effect and ameliorate the prognosis of patients with ACS within 6 weeks. This mechanism may involve HSF1/HSPs related signaling pathways. Early use of PCSK9i in patients with ACS should be strongly considered in clinical practice.

PCSK9 inhibitors ameliorate arterial stiffness in ACS patients: evidences from Mendelian randomization, a retrospective study and basic experiments.

Background: Current evidences suggest that Proprotein Convertase Subtilisin/kexin Type 9 inhibitors (PCSK9i) exhibit a protective influence on acute coronary syndrome (ACS). Nevertheless, further investigation is required to comprehend the impact and mechanisms of these pharmaceutical agents on inflammatory factors and arterial stiffness (AS) in patients with ACS. Consequently, the objective of this study is to ascertain the influence of PCSK9i on arterial stiffness in ACS patients and elucidate the underlying mechanisms behind their actions. Methods: This study employed Mendelian randomization (MR) analysis to examine the association between genetic prediction of PCSK9 inhibition and arterial stiffness. Data of 71 patients with ACS were retrospectively collected, including PCSK9i group (n = 36, PCSK9 inhibitors combined with statins) and control group (n = 35, statins only). Blood lipid levels, inflammatory markers and pulse wave velocity (PWV) data were collected before treatment and at 1 and 6 months after treatment for analysis. Additionally, cell experiments were conducted to investigate the impact of PCSK9i on osteogenesis of vascular smooth muscle cells (VSMCs), utilizing western blot (WB), enzyme-linked immunosorbent assay (ELISA), and calcification index measurements. Results: The results of the MR analysis suggest that genetic prediction of PCSK9 inhibition has potential to reduce the PWV. Following treatment of statins combined with PCSK9 inhibitors for 1 and 6 months, the PCSK9i group exhibited significantly lower levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), C-reactive protein (CRP), interleukin-6 (IL-6), fibrinogen (FIB) and procalcitonin (PCT) compared to the control group (p < 0.05). Additionally, PWV in the PCSK9i group demonstrated significant reduction after 6 months of treatment and was found to be associated with the circulating CRP level. In cell experiments, PCSK9i pretreatment ameliorated osteogenesis of VSMCs through reducing the deposition of calcium ions, alkaline phosphatase (ALP) activity, and expression of runt-related transcription factor 2 (RUNX2). Conclusion: PCSK9i have potential to enhance arterial stiffness in ACS patients. Specifically, at the clinical level, this impact may be attributed to alterations in circulating CRP levels. At the cellular level, it is associated with the signaling pathway linked to RUNX2.

Anatomical and Functional Discrepancy in Diabetic Patients With Intermediate Coronary Lesions　- An Intravascular Ultrasound and Quantitative Flow Ratio Study.

BACKGROUND: Data regarding the performance of computational fractional flow reserve in patients with diabetes mellitus (DM) remain scarce. This study sought to explore the impact of DM on quantitative flow ratio (QFR) and its association with intravascular ultrasound (IVUS)-derived anatomical references.Methods and Results: IVUS and QFR were retrospectively analyzed in 237 non-diabetic and 93 diabetic patients with 250 and 102 intermediate lesions, respectively. Diabetics were further categorized based on adequate (HbA1c <7.0%: 47 patients with 53 lesions) or poor (HbA1c ≥7.0%: 46 patients with 49 lesions) glycemic control. Lesions with QFR ≤0.8 or minimum lumen area (MLA) ≤4.0 mm2and plaque burden (PB, %) ≥70 were considered functionally or anatomically significant, respectively. PB increased, and MLA decreased stepwise across non-diabetics, diabetics with adequate glycemic control and those with poor glycemic control. In contrast, QFR was similar among the 3 groups. PB correlated significantly with the QFR for lesions in non-diabetics, but not for lesions in diabetics. DM was independently correlated with the functionally non-significant lesions (QFR >0.8) with high-risk IVUS features (MLA ≤4.0 mm2and PB ≥70; OR 2.053, 95% CI: 1.137-3.707, P=0.017). When considering the effect of glycemic control, HbA1c was an independent predictor of anatomical-functional discordance (OR 1.347, 95% CI: 1.089-1.667, P=0.006). CONCLUSIONS: Anatomical-functional discordance of intermediate coronary lesions assessed by IVUS and QFR is exacerbated in patients with diabetes, especially when glycemia is poorly controlled.

Aerobic Exercise Attenuates Pressure Overload-Induced Cardiac Dysfunction through Promoting Skeletal Muscle Microcirculation and Increasing Muscle Mass.

BACKGROUND: Aerobic exercise has been proven to have a positive effect on cardiac function after hypertension; however, the mechanism is not entirely clarified. Skeletal muscle mass and microcirculation are closely associated with blood pressure and cardiac function. OBJECTIVE: This study was designed to investigate the effects of aerobic exercise on the skeletal muscle capillary and muscle mass, to explore the possible mechanisms involved in exercise-induced mitigation of cardiac dysfunction in pressure overload mice. METHODS: In this study, 60 BALB/C mice aged 8 weeks were randomly divided into 3 groups: control (CON), TAC, and TAC plus exercise (TAE) group and utilized transverse aortic constriction (TAC) to establish hypertensive model; meanwhile, treadmill training is used for aerobic exercise. After 5 days of recovery, mice in the TAE group were subjected to 10-week aerobic exercise. Carotid pressure and cardiac function were examined before mice were executed by Millar catheter and ultrasound, respectively. Muscle mass of gastrocnemius was weighed; cross-sectional area and the number of capillaries of gastrocnemius were detected by HE and immunohistochemistry, respectively. The mRNA and protein levels of VEGF in skeletal muscle were determined by RT-PCR and western blot, respectively. RESULTS: We found that ① 10-week aerobic exercise counteracted hypertension and attenuated cardiac dysfunction in TAC-induced hypertensive mice; ② TAC decreased muscle mass of gastrocnemius and resulted in muscle atrophy, while 10-week aerobic exercise could reserve transverse aortic constriction-induced the decline of muscle mass and muscle atrophy; and ③ TAC reduced the number of capillaries and the protein level of VEGF in gastrocnemius, whereas 10-week aerobic exercise augmented the number of capillaries, the mRNA and protein levels of VEGF in mice were subjected to TAC surgery. CONCLUSIONS: This study indicates that 10-week aerobic exercise might fulfill its blood pressure-lowering effect via improving skeletal muscle microcirculation and increasing muscle mass.

Impact of Arterial Remodeling of Intermediate Coronary Lesions on Long-Term Clinical Outcomes in Patients with Stable Coronary Artery Disease: An Intravascular Ultrasound Study.

BACKGROUND: Treatment of coronary intermediate lesions remains a controversy, and the role of arterial remodeling patterns determined by intravascular ultrasound in intermediate lesion is still not well known. The aim of this study was to investigate the impact of arterial remodeling of intermediate coronary lesions on long-term clinical outcomes. METHODS: Arterial remodeling patterns were assessed in 212 deferred intermediate lesions from 162 patients after IVUS examination. Negative, intermediate, and positive remodeling was defined as a remodeling index of <0.88, 0.88∼1.0, and >1.0, respectively. The primary endpoint was the composite vessel-oriented clinical events, defined as the composition of target vessel-related cardiac death, target vessel-related myocardial infarction, and target vessel revascularization. Quantitative flow ratio was assessed for evaluating the functional significance of intermediate lesions. RESULTS: 72 intermediate remodeling lesions were present in 66 patients, whereas 77 negative remodeling lesions were present in 71 patients, and 63 positive remodeling lesions were present in 55 patients. Negative remodeling lesions had the smallest minimum lumen area (4.16 ± 1.03 mm2 vs. 5.05 ± 1.39 mm2 vs. 4.85 ± 1.76 mm2; P < 0.01), smallest plaque burden (63.45 ± 6.13% vs. 66.12 ± 6.82% vs. 71.17 ± 6.45%; P < 0.01), and highest area stenosis rate (59.32% ± 10.15% vs. 54.61% ± 9.09% vs. 51.67% ± 12.96%; P < 0.01). No significant difference was found in terms of quantitative flow ratio among three groups. At 5 years follow-up, negative remodeling lesions had a higher rate of composite vessel-oriented clinical event (14.3%), compared to intermediate (1.4%, P=0.004) or positive remodeling lesions (4.8%, P=0.06). After adjusting for multiple covariates, negative remodeling remained an independent determinant for vessel-oriented clinical event (HR: 4.849, 95% CI 1.542-15.251, P=0.007). CONCLUSION: IVUS-derived negative remodeling is associated with adverse long-term clinical outcome in stable patients with intermediate coronary artery stenosis.

Association of quantitative flow ratio-derived microcirculatory indices with anatomical-functional discordance in intermediate coronary lesions.

Discrepancy between coronary lesion severity and functional significance has always been a relevant issue in the management of patients undergoing coronary angiography and/or revascularization. We sought to investigate the relationship between quantitative flow ratio (QFR)-derived microcirculatory indices and anatomical-functional mismatch/reverse mismatch in intermediate coronary lesions. Intravascular ultrasound (IVUS) imaging and QFR were analyzed in 117 de novo intermediate coronary lesions. Lesions with QFR ≤ 0.8 were considered hemodynamically significant. Anatomical significance of the lesions was defined according to the best cutoff value of combined IVUS parameters for predicting QFR ≤ 0.8. QFR-derived microcirculatory indices including contrast-flow QFR minus fixed-flow QFR (cQFR-fQFR), hyperemic flow velocity and angiography-derived index of microcirculatory resistance (IMRangio) were calculated. The best cutoff values of IVUS parameters for predicting QFR ≤ 0.8 were minimum lumen area (MLA) 3.1mm2 and plaque burden (PB) 70%, with area under the curve of 0.635 and 0.703, respectively. The total discordance rate of lesion functional significance between IVUS and QFR assessments was 26.5%, with 21 lesions (17.9%) being classified as mismatch (MLA ≤ 3.1mm2 and PB ≥ 70% and QFR > 0.8) and 10 lesions (8.5%) as reverse-mismatch (MLA > 3.1 mm2 or PB < 70% and QFR ≤ 0.8). At multivariate analysis, IMRangio was identified as an independent predictor of mismatch (OR1.675, 95%CI:1.176-2.386, P = 0.004), whereas hyperemic flow velocity was identified as an independent predictor of reverse-mismatch (OR 1.233, 95%CI:1.073-1.416, P = 0.003). In intermediate coronary lesions, although MLA 3.1mm2 and PB 70% determined by IVUS are predictive of QFR-defined functional significance, the discordance rate remains substantial. QFR-derived microcirculatory indices are independently associated with anatomical-functional discordance between IVUS and QFR assessments.

The association between intravascular ultrasound-derived echo-attenuation and quantitative flow ratio in intermediate coronary lesions.

BACKGROUND: The clinical relevance of moderate coronary stenosis is determined by its morphological characteristics and physiological significance. We investigated the relationship between high-risk plaque characteristics detected by intravascular ultrasound and functional significance assessed with quantitative flow ratio (QFR) in intermediate coronary lesions. METHODS: QFR was retrospectively analyzed in 352 intermediate lesions from 330 patients undergoing intravascular ultrasound examination. The functional significance was defined as QFR ≤0.8. High-risk plaque morphologies including plaque rupture, echo-lucent, echo-attenuation, and spotty calcification were identified, and attenuation indices including maximum angle, attenuation length, and superficial attenuation were determined. Clinically relevant echo-attenuation was defined as an attenuation with a minimum lumen area ≤4.0 mm2 and plaque burden ≥70%. RESULTS: The prevalence of echo-attenuation was higher (63.0% vs. 37.6%, P=0.001) and attenuation length was longer (12.8±10.3 vs. 8.0±5.8 mm, P=0.015) in lesions with QFR ≤0.8 compared to those with QFR >0.8, associated with a higher rate of clinically relevant echo-attenuation (35.2% vs. 10.4%, P<0.001). On multivariable analysis, the presence of echo-attenuation was an independent predictor of QFR ≤0.8 [odds ratio (OR) 3.162, 95% confidence interval (CI): 1.263-7.917, P=0.014], whereas attenuation length was weakly correlated with QFR value (ß=-0.185, B=-0.002, 95% CI: -0.004 to -0.001, P=0.001). Receiver-operating characteristic curve analysis revealed that the best cutoff of QFR in predicting clinically relevant echo-attenuation was 0.82 [area under the curve (AUC) =0.696, 95% CI: 0.616-0.775, P<0.001]. CONCLUSIONS: The presence of intravascular ultrasound-derived echo-attenuation confers an increased risk of QFR-defined functional significance in intermediate coronary lesions. KEYWORDS: Coronary artery disease; intermediate coronary lesion; quantitative flow ratio (QFR); intravascular ultrasound (IVUS); echo-attenuation.

Predictors and prognosis of left ventricular thrombus in post-myocardial infarction patients with left ventricular dysfunction after percutaneous coronary intervention.

BACKGROUND: We aimed to investigate the predictors and prognosis of left ventricular thrombus (LVT) in patients admitted for post-myocardial infarction (MI) and left ventricular dysfunction after contemporary percutaneous coronary intervention (PCI). METHODS: We prospectively enrolled 267 consecutive post-MI patients with left ventricular ejection fraction (LVEF) <0.45 based on the Shanghai East Hospital PCI database since 2012. Altogether 25 (9.36%) patients were selected as the LVT group. Baseline, angiographic, procedural characteristics and 1-year clinical outcomes were compared by Chi-square test, t-test or Kaplan-Meier survival analysis as appropriate. Receiver operating characteristic (ROC) curves were plotted for the accuracy of the multivariate analysis model. A multiple logistic regression was applied to predict LVT formation. RESULTS: The independent risk factors of LVT were left ventricular aneurysm [odds ratio (OR): 1.29, 95% confidence interval (CI): 1.09-1.52, P<0.01], incomplete revascularization (OR: 0.05, 95% CI: 0.01-0.35, P<0.01), SYNTAX score (OR: 1.28, 95% CI: 1.14-1.43, P<0.01) and D-dimer (OR: 1.90, 95% CI: 1.19-3.04, P<0.01). The SYNTAX score and D-dimer effectively indicated the development of LVT with optimal cutoff values of 29.50 and 1.53 mg/L, respectively. Patients with LVT had significantly worse outcomes at 1-year clinical follow-up, especially higher incidence of ischemic or hemorrhagic stroke. CONCLUSIONS: This study indicated that the presence of left ventricular aneurysm, incomplete revascularization, higher SYNTAX score and D-dimer level were the independent predictors of LVT formation in post-MI and LV dysfunction patients, which related to worse clinical outcomes. Future studies for early intervention and complete revascularization in high-risk subgroup patients are expected.

Downregulation of MiR-199b-5p Inducing Differentiation of Bone-Marrow Mesenchymal Stem Cells (BMSCs) Toward Cardiomyocyte-Like Cells via HSF1/HSP70 Pathway.

BACKGROUND Bone-marrow mesenchymal stem cells (BMSCs) are pluripotent stem cells with potent self-renewal and differentiation ability that are widely used in transplantation of cell therapy. But the mechanism on microRNA (miRNA) regulating stem cell differentiation is complicated and unclear. The aim of this study was to investigate whether miR-199b-5p is involved in differentiation of cardiomyocyte-like cells and identify potential signal pathways in BMSCs. MATERIAL AND METHODS Mouse BMSCs were treated with 5-azacytidine and transfected by miR-199b-5p mimic and inhibitor, respectively. qRT-PCR was used to detect the expression of miR-199b-5p in BMSCs, 5-azacytidine treated BMSCs, and neonatal murine cardiomyocytes. The expression of cardiac specific genes and the HSF1/HSP70 signal pathway were examined by qRT-PCR or western blotting. The proliferation and migration of BMSCs were evaluated by CCK-8 assay and wound-healing assay. RESULTS The expression of miR-199b-5p decreased gradually in the process of differentiation of BMSCs toward cardiomyocyte-like cells. The expression of cardiac specific genes and HSF1/HSP70 were increased in the miR-199b-5p inhibitor group; however, the miR-199b-5p mimic group presented an opposite result. Both the miR-199b-5p inhibitor group and the miR-199b-5p mimic group had no influence on BMSCs proliferation and migration. Using lentivirus vectors bearing HSF1 shRNA to silence HSF1 and HSP70, the anticipated elevated expression effect of cardiac specific genes induced by miR-199b-5p inhibitor was suppressed. CONCLUSIONS Downregulation of miR-199b-5p induced differentiation of BMSCs toward cardiomyocyte-like cells partly via the HSF1/HSP70 signaling pathway, and had no influence on BMSCs proliferation and migration.

Role of heat shock transcription factor 1(HSF1)-upregulated macrophage in ameliorating pressure overload-induced heart failure in mice.

In order to explore the role of macrophages in HSF1-mediated alleviation of heart failure, mice model of pressure overload-induced heart failure was established using transverse aortic constriction (TAC). Changes in cardiac function and morphology were studied in TAC and SHAM groups using ultrasonic device, tissue staining, electron microscopy, real-time quantitative polymerase chain reaction (RT-QPCR), and Western blotting. We found that mice in the TAC group showed evidence of impaired cardiac function and aggravation of fibrosis on ultrasonic and histopathological examination when compared to those in the SHAM group. The expressions of HSF1, LC3II/LC3I, Becline-1 and HIF-1, as well as autophagosome formation in TAC group were greater than that in SHAM group. On sub-group analyses in the TAC group, improved cardiac function and alleviation of fibrosis was observed in the HSF1 TG subgroup as compared to that in the wild type subgroup. Expressions of LC3II/LC3I, Becline-1 and HIF-1, too showed an obvious increase; and increased autophagosome formation was observed on electron microscopy. Opposite results were observed in the HSF1 KO subgroup. These results collectively suggest that in the pressure overload heart failure model, HSF1 promoted formation of macrophages by inducing upregulation of HIF-1 expression, through which heart failure was ameliorated.

Role of miR-199b-5p in regulating angiogenesis in mouse myocardial microvascular endothelial cells through HSF1/VEGF pathway.

Our study explored effects of miR-199b-5p on angiogenesis in mouse myocardial microvascular endothelial cells (MMVECs) and the involved working mechanisms. We applied explant culture to incubate C57/BL6 mouse MMVECs. Lipofection was used to transfect miR-199b-5p mimic, miR-199b-5p inhibitor and miR-199b-5p scramble respectively. MMVECs were divided into miR-199b-5p up-regulation, miR-199b-5p down-regulation and control groups based on above sequence. Expressions of miR-199b-5p, heat shock factor protein 1 (HSF1) mRNA were assessed by real-time quantitative polymerase chain reaction (RT-QPCR). Expressions of HSF1 and vascular endothelial growth factor (VEGF) were assessed by Western Blotting. Cell proliferation was assessed by CCK8. Tubule formation assay was conducted to assess formation of blood vessels. Results showed that miR-199b-5p up/down-regulation groups exhibited no obvious differences in the expressions of HSF1 mRNA compared to control group. However, miR-199b-5p up-regulation group recorded lower expressions of HSF1 and VEGF in the level of protein, and reduced cell proliferation and tubule formation. Whereas, miR-199b-5p down-regulation group presented the contrary results. The experiment indicated that miR-199b-5p can regulate proliferation and angiogenesis in mouse MMVECs through the pathway of HSF1/VEGF.

Role of HSF1-upregulated AC6 in ameliorating heart failure in mice.

PURPOSE: Our previous studies discovered that Heat shock factor 1(HSF1) can alleviate pressure overload induced heart failure in mice. However, its molecular mechanisms are yet to be further explained. Many studies have already verified that Adenylyl Cyclase 6 (AC6) can ameliorate heart failure, but it is still unknown whether or not the pathway HSF1 is involved in the process. Our preliminary experiment showed that the expression level of AC6 is positively associated with HSF1. Therefore, in the present study, we aimed to explore whether HSF1 can play its role in ameliorating heart failure by regulating AC6, and how the potential internal mechanisms work. METHODS: We applied the Transverse Aortic Constriction (TAC) for 4 weeks to develop the C57BL/6 mice pressure overload induced heart failure model. First, the mice were divided into TAC group and SHAM group. Changes in the cardiac function and morphology of the mice were observed by an ultrasonic device and Masson staining slices, expressions of AC6 mRNA were observed by RT-QPCR, expressions of HSF1 and proteinkinase A (PKA) were examined by Western Blotting, and the levels of cyclic adenosine monophosphate (cAMP) from aortic blood were measured by ELISA. Second, the TAC group were further divided into subgroups of HSF1 transgene mice, HSF1 knockout mice and wild type mice, followed by the aforesaid observations. RESULTS: In the SHAM group, no obvious variations of cardiac function, AC6 mRNAHSF1, PKA, cAMP and other test results were found among each of the subgroups. Compared to the SHAM group, the TAC group presented clearly weakened heart functions, while, expressions of AC6 mRNA, HSF1, PKA and cAMP all recorded obvious increases. In the TAC group, compared to the WT subgroup, the HSF1 KO subgroup presented decreases in expressions of AC6 mRNA, HSF1, PKA and cAMP, and at the same time, the heart functions were weaker, while, the HSF1 TG subgroup recorded the contrary results. CONCLUSION: In the pressure overload heart failure model, HSF1 can ameliorate heart failure by positively regulating the pathway of AC6/cAMP/PKA.