Peri-operative Takotsubo syndrome after non-cardiac surgery: a retrospective nested case-control study.

AIMS: Takotsubo syndrome (TTS) is an acute reversible cardiac dysfunction that may occur during the peri-operative period and among patients with serious illness. We aimed to evaluate the clinical characteristics, peri-operative management, and prognosis of peri-operative TTS (pTTS) and explore the factors associated with pTTS. METHODS: We conducted a retrospective nested case-control study using the database of patients who underwent in-hospital non-cardiac surgeries between January 2017 and December 2020 in Peking University Third hospital. Cases were adult patients diagnosed TTS at discharge who were matched with four controls based on operative types. Multivariable conditional logistic regression was used to identified the factors associated with pTTS. The area under the curve (AUC) was used to evaluate the diagnostic efficacy. RESULTS: Among the 128 536 patients underwent non-cardiac surgery, 20 patients with pTTS and 80 patients without were enrolled in this study. The incidence of pTTS was about 0.016% in our centre. The median age of patients with pTTS was 52.5 (38.25, 76.25) years, although 90% of them were female. Fifty per cent (9 cases) of female patients were pre-menopausal. Caesarean section has the highest proportion of pTTS (30% of the pTTS cases) with the incidence of caesarean section-related pTTS of 0.06% in our centre. A high prevalence of non-apical ballooning pattern of regional wall motion abnormality (seven cases, 35%) and a high mortality (two cases, 10%) were observed. Left ventricular ejection fraction (LVEF) of patients with pTTS was significantly decreased (41.7 ± 8.8%). In the acute phase, supportive treatments aiming to reduce life-threatening complications were main treatment strategies. After receiving systematic treatment, significant improvements were observed in LVEF (63.1 ± 13.5%), with median recovery time of LVEF of 7.48 days. Leucocyte count [odds ratio (OR): 4.59; 95% confidence interval (CI): 1.10-19.15], haemoglobin (HGB) (OR: 10.52; 95% CI: 1.04-106.36), and the revised cardiac risk index (RCRI) score (OR: 6.30; 95% CI: 1.05-37.88) were the factors significantly associated with pTTS. The RCRI score performed poorly in the prediction of pTTS (AUC: 0.630; 95% CI: 0.525-0.735). After adding leucocyte count and HGB into the RCRI score, the AUC was significantly improved (AUC: 0.768; 95% CI: 0.671-0.865; P = 0.001). CONCLUSIONS: Patients with pTTS have some differences compared with common TTS, including higher proportion of pre-menopausal female, higher prevalence during caesarean section, higher prevalence of non-apical ballooning pattern of regional wall motion abnormality, and higher mortality. The RCRI score performed poorly in the evaluation of pTTS. Adding HGB and leucocyte count into the RCRI score could significantly improve its predictive performance.

Development and Validation of Predictive Model-HASBLAD Score-For Major Adverse Cardiovascular Events During Perioperative Period of Non-cardiac Surgery: A Single Center Experience in China.

Background: Major adverse cardiovascular events (MACEs) represent a significant reason of morbidity and mortality in non-cardiac surgery during perioperative period. The prevention of perioperative MACEs has always been one of the hotspots in the research field. Current existing models have not been validated in Chinese population, and have become increasingly unable to adapt to current clinical needs. Objectives: To establish and validate several simple bedside tools for predicting MACEs during perioperative period of non-cardiac surgery in Chinese hospitalized patients. Design: We used a nested case-control study to establish our prediction models. A nomogram along with a risk score were developed using logistic regression analysis. An internal cohort was used to evaluate the performance of discrimination and calibration of these predictive models including the revised cardiac risk index (RCRI) score recommended by current guidelines. Setting: Peking University Third Hospital between January 2010 and December 2020. Patients: Two hundred and fifty three patients with MACEs and 1,012 patients without were included in the training set from January 2010 to December 2019 while 38,897 patients were included in the validation set from January 2020 and December 2020, of whom 112 patients had MACEs. Main Outcome Measures: The MACEs included the composite outcomes of cardiac death, non-fatal myocardial infarction, non-fatal congestive cardiac failure or hemodynamically significant ventricular arrhythmia, and Takotsubo cardiomyopathy. Results: Seven predictors, including Hemoglobin, CARDIAC diseases, Aspartate aminotransferase (AST), high Blood pressure, Leukocyte count, general Anesthesia, and Diabetes mellitus (HASBLAD), were selected in the final model. The nomogram and HASBLAD score all achieved satisfactory prediction performance in the training set (C statistic, 0.781 vs. 0.768) and the validation set (C statistic, 0.865 vs. 0.843). Good calibration was observed for the probability of MACEs in the training set and the validation set. The two predictive models both had excellent discrimination that performed better than RCRI in the validation set (C statistic, 0.660, P < 0.05 vs. nomogram and HASBLAD score). Conclusion: The nomogram and HASBLAD score could be useful bedside tools for predicting perioperative MACEs of non-cardiac surgery in Chinese hospitalized patients.

Connexin43 and Myocardial Ischemia-Reperfusion Injury.

BACKGROUND: Recently, the treatment and prevention of ischemic cardiomyopathy is one of the emerging research topics in the cardiovascular field. Gap junction is the basic structure of cardiac electrophysiology. Connexin is the basic unit of gap junctions. Connexin43(CX43) is the most abundant member of Cx family in the heart, the normal expression of Cx43 is important for heart development, electrically coupled cardiomyocytes activities and coordination of myocardial function. The connection between Cx43 and myocardial ischemia/reperfusion or reperfusion injury has become the focus of current research. METHODS: We undertook a structured search of bibliographic database for peer-reviewed research literature using a focused review question and inclusion/exclusion criteria. The quality of retrieved papers was appraised using standard tools. The characteristics of screened papers were described, and a deductive qualitative content analysis methodology was applied to analyze the interventions and findings of included studies using a conceptual framework. RESULTS: Twenty-one papers were included in the review, eight papers outlined the relationship of Cx43 and reperfusion arrhythmias. Eight papers pointed out the effect on the infarct size of Cx43. CONCLUSION: The findings of this review confirm that Cx43 is the most abundant member of Cx family in the heart and is vital for myocardial protection during ischemia/reperfusion process and for ischemia/reperfusion injury. Many of its mechanism are still not very clear and require future research in the future.

Antiproteinase 3 Positive Eosinophilic Granulomatosis with Polyangiitis Presenting with Heart Failure and Intraventricular Thrombosis.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare systemic vasculitis commonly with cardiac complications. We describe a case of anti-PR3 ANCA-positive EGPA complicated by congestive heart failure and intraventricular thrombosis. Interestingly, the thrombus was resolved rapidly with steroid and cyclophosphamide in the setting of interrupted anticoagulation. To the best of our knowledge, we report the first case of anti-PR3 positive EGPA with extensive cardiac involvement. Our patient had overlapping features with previously studied ANCA-positive and ANCA-negative EGPA cases. We also hypothesize that the thrombogenic potential of eosinophils may play a central role in thrombogenesis in EGPA and aggressive immunosuppressive therapy remains the cornerstone of treatment, and the addition of anticoagulation therapy in the setting of thrombus formation and also very high risk of bleeding needs to be considered cautiously.

Macrophage Foam Cell-Derived Extracellular Vesicles Promote Vascular Smooth Muscle Cell Migration and Adhesion.

BACKGROUND: A new mechanism for intercellular communication has recently emerged that involves intercellular transfer of extracellular vesicles (EVs). Several studies have indicated that EVs may play a potential role in cell-to-cell communication between macrophage foam cells and vascular smooth muscle cells (VSMCs) in atherosclerotic lesion. METHODS AND RESULTS: This study involved the comparison of circulating EVs from atherosclerotic patients and control participants. The results showed that the circulation of the patients contained more leukocyte-derived EVs and that these EVs promoted more VSMC adhesion and migration than those of healthy participants. We then established a macrophage foam cell model and characterized the EVs from the macrophages. We used flow cytometric analyses and cell migration and adhesion assays and determined that the foam cells generated more EVs than the normal macrophages and that the foam cell-derived EVs were capable of promoting increased levels of VSMC migration and adhesion. Furthermore, we performed a proteomic analysis of the EVs. The data showed that the foam cell-derived EVs may promote VSMC adhesion and migration by regulating the actin cytoskeleton and focal adhesion pathways. In addition, Western blotting revealed that foam cell-derived EVs could promote the phosphorylation of ERK and Akt in VSMCs in a time-dependent manner. We also found that foam cell-derived EVs could enter the VSMCs and transfer integrins to the surface of these cells. CONCLUSIONS: The data in our present study provide the first evidence that EVs from foam cells could promote VSMC migration and adhesion, which may be mediated by the integration of EVs into VSMCs and the subsequent downstream activation of ERK and Akt.

Ischemic preconditioning inhibits mitochondrial permeability transition pore opening through the PTEN/PDE4 signaling pathway.

OBJECTIVES: Ischemic preconditioning (IPC) induces cardioprotection against ischemia-reperfusion (IR) injury by inhibiting the mitochondrial permeability transition pore (mPTP). Here, we tested the hypothesis that IPC-induced cardioprotection is mediated by the phosphatase PTEN and PDE4 (phosphodiesterase 4). METHODS: Isolated hearts from wild-type mice (WT, n = 110) and myocyte-specific PTEN-knockout mice (PKO, n = 94) were exposed to IPC or control conditions followed by IR. Subcellular fractionation was performed by sucrose gradient ultracentrifugation. RESULTS: IPC limited myocardial infarct size (IS) in WT mice. The PDE4 inhibitor rolipram abolished the protective effect of IPC. However, small IS was found in PKO hearts after IR, and IPC did not decrease IS but enlarged it in PKO hearts. IPC promoted PDE4D localization to caveolin-3-enriched fractions in WT mice by increasing Akt levels at the caveolae. In PKO hearts, basal PDE4D levels were elevated at the caveolae, and IPC decreased PDE4D levels. Consistent with the subcellular PDE4D protein levels and its activity, elevation in intracellular Ca(2+) levels in the ischemic heart and opening of mPTP after IR were inhibited by IPC in WT mice, but not by IPC in PKO mice. CONCLUSIONS: IPC inhibits mPTP opening by regulating the PTEN/PDE4 signaling pathway.

High-density lipoprotein nitration and chlorination catalyzed by myeloperoxidase impair its effect of promoting endothelial repair.

High-density lipoprotein (HDL) plays a key role in protecting against atherosclerosis. In cardiovascular disease, HDL can be nitrated and chlorinated by myeloperoxidase (MPO). In this study, we discovered that MPO-oxidized HDL is dysfunctional in promoting endothelial repair compared to normal HDL. Proliferation assay, wound healing, and transwell migration experiments showed that MPO-oxidized HDL was associated with a reduced stimulation of endothelial cell (EC) proliferation and migration. In addition, we found that Akt and ERK1/2 phosphorylation in ECs was significantly lower when ECs were incubated with oxidized HDL compared with normal HDL. To further determine whether oxidized HDL diminished EC migration through the PI3K/Akt and MEK/ERK pathways, we performed experiments with inhibitors of both these pathways. The transwell experiments performed in the presence of these inhibitors showed that the migration capacity was reduced and the differences observed between normal HDL and oxidized HDL were diminished. Furthermore, to study the effects of oxidized HDL on endothelial cells in vivo, we performed a carotid artery electric injury model on nude mice injected with either normal or oxidized HDL. Oxidized HDL inhibited reendothelialization compared to normal HDL in vivo. These findings implicate a key role for MPO-oxidized HDL in the pathogenesis of cardiovascular disease.

Ischemic preconditioning attenuates mitochondrial localization of PTEN induced by ischemia-reperfusion.

Although the induction of myocyte apoptosis by ischemia-reperfusion (I/R) is attenuated by ischemic preconditioning (IPC), the underlying mechanism is not fully understood. Phosphatase and tensin homologs deleted on chromosome 10 (PTEN) promotes apoptosis through Akt-dependent and -independent mechanisms. We tested the hypothesis that IPC attenuates the mitochondrial localization of PTEN in the myocardium induced by I/R. Isolated hearts from wild-type mice were exposed to IPC or normal perfusion followed by 30 min of ischemia and reperfusion. IPC attenuated myocardial infarct size and apoptosis after I/R. Heart fractionation showed that mitochondrial PTEN and Bax protein levels and the physical association between them were increased by 30 min of I/R and that IPC attenuated all of these effects of I/R. Muscle-specific PTEN knockout decreased mitochondrial Bax protein levels in the reperfused myocardium and increased cell survival. To determine whether PTEN relocalization to mitochondria was influenced by I/R-induced production of ROS, hearts were perfused with N-acetylcysteine (NAC) to scavenge ROS or H(2)O(2) to mimic I/R-induced ROS. Mitochondrial PTEN protein levels were decreased by NAC and increased by H(2)O(2). PTEN protein overexpression was generated in mouse hearts by adenoviral gene transfer. PTEN overexpression increased mitochondrial PTEN and Bax protein levels and ROS production, whereas muscle-specific PTEN knockout produced the opposite effects. In conclusion, myocardial I/R causes PTEN localization to the mitochondria, related to the generation of ROS; IPC attenuates the mitochondrial localization of PTEN after I/R, potentially inhibiting the translocation of Bax to the mitochondria and resulting in improved cell viability.

PTEN inhibitors cause a negative inotropic and chronotropic effect in mice.

Inactivation of phosphatase and tensin homologue deleted on chromosome ten (PTEN) decreases cardiac contractility under basal conditions and induces cardioprotection against ischemia-reperfusion injury. However, the pharmacological effect of PTEN inhibitors on cardiac contractility has not been studied before. In the present study, we investigated the hypothesis that PTEN inhibition decreases cardiac contractility in mice. We first exposed isolated mouse hearts to the PTEN inhibitor bpV(phen) (40µM), the phosphoinositide-3 kinase inhibitor wortmannin (1µM), and the PTEN-resistant PIP3 analog 3-phosphorothioate-PtdIns(3,4,5)P3 (3-PT-PTP, 0.5µM) for 10min. Left ventricular pressure was measured by a Mikro-tip pressure catheter. We then inhibited PTEN in mice by intra-peritoneal injection of VO-OHpic (10µg/kg) 30min before ischemia and then exposed them to 30min of ischemia and 120min of reperfusion. At the end of the experiments, hearts were isolated for measurement of myocardial infarct size by 1.5% triphenyltetrazolium chloride. Left ventricular systolic pressure and heart rate were significantly decreased by bpV(phen). Consistent with the result, the maximal rate of left ventricular pressure increase or decrease was significantly decreased by bpV(phen). 3-PT-PIP3 mimicked the effect of bpV(phen), and the opposite effect on cardiac contractility was seen with wortmannin. Moreover, inhibition of PTEN in vivo by VO-OHpic decreased left ventricular systolic pressure and heart rate before ischemia, but resulted in an increase in cardiac functional recovery and a decrease in myocardial infarct size after ischemia-reperfusion. In conclusion, PTEN inhibition causes a negative inotropic and chronotropic effect while inducing cardioprotection against ischemia-reperfusion injury.

Evidence for a role of immunoproteasomes in regulating cardiac muscle mass in diabetic mice.

The ubiquitin-proteasome system plays an important role in regulating muscle mass. Inducible immunoproteasome subunits LMP-2 and LMP-7 are constitutively expressed in the heart; however, their regulation and functions are poorly understood. We here investigated the hypothesis that immunoproteasomes regulate cardiac muscle mass in diabetic mice. Type 1 diabetes was induced in wildtype mice by streptozotocin. After hyperglycemia developed, insulin and the proteasome inhibitor epoxomicin were used to treat diabetic mice for 6weeks. Isolated mouse hearts were perfused with control or high glucose solution. Catalytic proteasome beta-subunits and proteolytic activities were analyzed in the heart by immunoblotting and fluorogenic peptide degradation assays, respectively. Insulin and epoxomicin blocked loss of heart weight and improved cardiac function in diabetic mice. LMP-7 and its corresponding chymotryptic-like proteasome activity were increased in diabetic hearts and high glucose-treated hearts. Myosin heavy chain protein was decreased in diabetic hearts, which was largely reversed by epoxomicin. High glucose decreased LMP-2 protein levels in perfused hearts. In diabetic hearts, LMP-2 expression was downregulated whereas expression of the phosphatase and tensin homologue deleted on chromosome ten (PTEN) and the muscle atrophy F-box were upregulated. Moreover, mice with muscle-specific knockout of PTEN gene demonstrated increased cardiac muscle mass, while mice with LMP-2 deficiency demonstrated PTEN accumulation, muscle mass loss, and contractile impairment in the heart. Therefore, we concluded that high glucose regulates immunoproteasome subunits and modifies proteasome activities in the heart, and that dysregulated immunoproteasome subunits may mediate loss of cardiac muscle mass in experimental diabetic mice.

[Adhesion between monocytes and vascular smooth muscle cells induced by integrin beta1-mediated platelet-derived growth factor].

OBJECTIVE: To investigate the effects of platelet-derived growth factor (PDGF)-BB on the vascular smooth muscle cell (VSMC)-monocyte interaction and the mechanism thereof. METHODS: Rat aortic VSMC were pretreated with PDGF-BB of the concentrations of 0, 2.5, 5, 10, and 20 ng/ml for 8 hours and then co-incubated with human monocytes of the line THP-1 labeled with PKH26, a cellular membrane fluorescent marker, i.e., to be subjected to binding assay to observe the dose-effect relationship. Other VSMC were co-cultured with PDGF of the concentration of 10 ng/ml for 1, 2, 4, 12, and 24 hours respectively and then interacted with PKH26-abeled THP-1 cells so as to observe the time-response relationship. Monoclonal antibody against integrin beta1 was co-cultured with VSMC for 30 min, and then PKH26-labeled THP-1 cells were added to block the effect of PDGF. After the incubation of THP-1 cells and VSMC, the amount of bound cells was counted using fluorescent phase-contrast microscopy. The effect of PDGF on the expression of integrin beta1 was detected by Western blotting. RESULTS: The amounts of THP-1 cells bound to VSMC pretreated with PDGF of the concentrations of 2.5, 5, 10, and 20 ng/ml respectively were 1.1, 2.1, 3.1, and 4.4 times that of the untreated cells. Incubated with 10 ng/ml PDGF for 0-18 h, the adhesion rate between the VSMC and THP-1 cells increased time-1dependently. After the blocking by the antibody against integrin beta1, the adhesion rate between the VSMC and THP-1 cells decreased from (25.4+/-11.4)% to (9.2+/-4.1)% (P<0.01). Western blotting showed that the level of integrin beta1 of the VSMC treated by 10 ng/ml PDGF increased since 4 h after the treatment, peaked 8 h later, and then decreased gradually. CONCLUSION: PDGF-BB can induce the binding of monocytes to VSMC via the integrin-beta1 signaling pathway. The effect may therefore facilitate the progression of atherosclerosis by augmenting the VSMC-monocyte adhesive interaction.

[Effects of tissue inhibitor of matrix metalloproteinases-4 on the activities of matrix metalloproteinases and collagen of artery: experiment with rats].

OBJECTIVE: To investigate the effects of tissue inhibitor of matrix metalloproteinases-4 (TIMP-4) on the activities of matrix metalloproteinases (MMPs) and the collagen deposition. METHODS: Vascular smooth muscle cells (VSMCs) of rat thoracic aorta were cultured and divided into 3 groups: 2 groups to be transfected with adenovirus vector containing green fluorescence protein (AdGFP) or adenovirus vector containing TIMP-4 (AdTIMP-4), and one group un-transfected. Zymography and reverse zymography were used to detect the activities of MMP-2, MMP-9 and TIMP-4 in the supernatants. Male Wistar rats underwent balloon injury of common carotid artery and then divided into 3 groups: pure injury group, AdGFP transfection group, and AdTIMP-4. transfection group. Four and 28 days later 3 and 6 rats were killed in each group respectively to undergo microscopy and examination of the activities of MMP-2, MMP-9, and TIMP-4, and collagen quantity. RESULTS: The MMP-2 activity in the VSMC culture fluid supernatant of the AdTIMP-4 group was decreased dose-dependently, however, the activity of MMP-9 did not changed significantly among the 3 groups. Bands of activated MMP-2 and MMP-9 could not be examined in the normal vessel tissues. Four hours after the injury, the activity of MMP-2 was significantly increased in the pure injury group and AdGFP group, however, was significantly decreased in the AdTIMP-4 group. Four days later no MMP activity could be detected in either group. The neoformation of tunica intima was inhibited by 66% in the AdTIMP-4 group, The collagen quantity per vessel cell was 12.1 +/- 1.0 in the AdGFP group, not significantly different from that of in the AdTIMP-4 group (11.9 +/- 1, P > 0.05), and the collagen quantity per tunica adventitia cell in the AdTIMP-4 group was 118 +/- 13, not significantly different from that of the pure injury group (135 +/- 11, P > 0.05). CONCLUSION: The regulation of MMP/TIMP balance by TIMP-4 may control the metabolism of collagen and play an important role in the vascular repair process.

Superior neovascularization and muscle regeneration in ischemic skeletal muscles following VEGF gene transfer by rAAV1 pseudotyped vectors.

Recombinant adeno-associated virus serotype 2 (rAAV2) vector has been widely employed for gene therapy. Recent progress suggests that the new serotypes of AAV showed a better performance than did AAV2 in normal tissues. Here, we evaluate the potential role of human vascular endothelial growth factor (VEGF) gene transfer using rAAV vector pseudotyped with serotype 1 capsid proteins (rAAV1) in the treatment of muscle ischemia. In ischemic skeletal muscles, the rAAV1-LacZ vector allowed higher level, broader distribution, and long-lasting gene expression compared with the rAAV2-LacZ vector. Muscle VEGF165 production following the rAAV1-VEGF165 vector injection was 5-10 times higher than that following the rAAV2-VEGF165 vector injection. VEGF165 production mediated by the rAAV1-VEGF165 vector stimulated a large set of neovascularization with relatively mature vascular structures and enhanced muscle regeneration in the ischemic skeletal muscles. Thus, the rAAV1-VEGF165 vector mediated gene transfer may be a therapeutic approach to peripheral vascular diseases.

[Combined gene therapy enhances collateral vascularization in coronary artery occlusion swine model].

OBJECTIVE: To investigate the efficacy of combined gene transfer of vascular endothelial growth factor (VEGF) and angiotensin-1 (Ang-1) in swine coronary artery occlusion. METHODS: Swine underwent left thoracotomy followed by ligation of left anterior descending coronary artery. Constructed PCD(2)/VEGF and/or PCD(2)/Ang-1 eukaryotic expression plasmid was directly injected into the swine myocardium. RT-PCR, immunohistochemistry, capillary density and arteriole density were used to detect gene expression and biological effect. Coronary angiography was done to evaluate collateral circulation of the occluded artery. RESULTS: High levels of VEGF and Ang-1 mRNA and protein expression were detected. There was a significant increase in the number of capillaries and arterioles as compared with a control group (P < 0.05). Capillary density and arteriole density of the combination therapy group were higher than those of the swing receiving either therapy alone. Coronary angiography showed better collateral circulation in the combination therapy group. CONCLUSIONS: Direct injection of PCD(2)/VEGF and PCD(2)/Ang-1 can transfect the myocardium and express VEGF and Ang-1 protein. Combined gene transfer of VEGF and Ang-1 can increase capillary and arteriole number and enhance collateral circulation of the occluded coronary artery more effectively.