Adherence, belief, and knowledge about oral anticoagulants in patients with bioprosthetic heart valve replacement: a cross-sectional study.

Aims: To investigate adherence to oral anticoagulants among patients after mechanical heart valve (BHV) replacement and further examine the mediating role of medication belief in the relationship between knowledge and medication adherence. Background: The number of patients who undergo BHV replacement has increased in recent years. Short-term anticoagulant therapy is recommended for patients after BHV replacement. However, little is known about adherence to oral anticoagulant therapy and the underlying mechanisms among patients with BHV replacement. Methods: A cross-sectional study was conducted between September 2022 and November 2022. A convenience sample of 323 patients who underwent BHV replacement was recruited from a tertiary public hospital in Southwest China. Data were collected by using the 8-item Morisky Medication Adherence Scale, Beliefs about Medicines Questionnaire-specific, and the Knowledge of Anticoagulation Questionnaire. The mediation model was tested by Hayes's PROCESS macro. The STROBE checklist was used. Results: Approximately 17.3% of participants had low adherence, 47.1% had medium adherence, and only 35.6% reported high adherence to oral anticoagulants. Knowledge and necessity beliefs were positively related to medication adherence, while concern beliefs were negatively correlated with medication adherence. Medication belief mediated the relationship between knowledge and adherence to oral anticoagulants. Conclusion: Patients with BHV replacement demonstrated relatively low adherence to oral anticoagulant therapy. Efforts to enhance medication adherence should consider improving patients' knowledge and medication beliefs.

[Endoplasmic Reticulum Stress and Mitochondrial Damage in Rat Cardiomyocytes after Acute Myocardial Infarction].

OBJECTIVE: To study the alterations of endoplasmic reticulum (ER) stress and mitochondrial damage after acute myocardial infarction (AMI). METHODS: A total of 40 SD rats were used in this study and 32 of them were subjected to AMI by ligation of left anterior descending artery. The rats were sacrificed and the heart tissues were collected after 1 h, 2 h, 4 h and 6 h of AMI ( n=8 per group). The mRNA levels of activating transcription factor 6 alpha ( ATF6) and immunoglobulin heavy chain binding potein ( BiP), as well as the expression of mitochondrial DNA (mtDNA) in cytoplasm were detected by RT-PCR. The ATP levels in the cardiomyocytes were detected by a commercial ATP assay kit. RESULTS: The mRNA levels of ATF6 and BiP were significantly increased after 1 h of AMI, which were maintained at high level from 2 h of AMI to the end of the experiment ( P<0.05). The ATP concentrations in the cardiomyocytes were significantly elevated after 1 h of AMI but remarkably decreased after 4 h and 6 h of AMI ( P<0.05). The release of mtDNA in cytoplasm was significantly increased after 2 h of AMI, followed by further elevations at 4 h and 6 h after AMI ( P<0.05). CONCLUSION: Mitochondrial damage is secondary to ER stress in AMI.

Epigallocatechin gallate attenuates mitochondrial DNA-induced inflammatory damage in the development of ventilator-induced lung injury.

OBJECTIVE: We aim to investigate the role of mitochondrial DNA (mtDNA), a novel endogenous pro-inflammatory cytokine, in the development of ventilator-induced lung injury (VILI). Moreover, the protective effect of epigallocatechin gallate (EGCG) on VILI through inhibiting local mtDNA release was examined. METHODS: From March 2015 to March 2016, bronchoalveolar lavage fluid (BALF) from 36 patients with VILI and well-matched 36 patients without VILI after major surgery were consecutively collected. The expression levels of mtDNA and inflammatory cytokines in BALF were tested. SD rats were divided into five groups: control, low tidal volume (7 ml/kg) group, high tidal volume (HTV, 40 ml/kg) group, HTV+low dose EGCG and HTV+high dose EGCG groups. BALF were collected to examine the expression levels of mtDNA and several inflammatory cytokines and the lung tissue was harvested for pathological examinations. In addition, cyclic stretch cell culture was used and culture media was collected to analyze expressions of inflammatory cytokines. Administration of mtDNA in a rat model and in vitro cell culturing were used to confirm its pro-inflammatory properties in the development of inflammatory lung injury. RESULTS: A Significant elevation of mtDNA was detected in BALF from patients with VILI (581 ±â€¯193 vs. 311 ±â€¯137, p < 0.05) and also in rats ventilated with HTV. EGCG could significantly inhibit HTV-induced local mtDNA release and attenuate the level of inflammatory lung injuries (reduced infiltration of local inflammatory cells, lower lung wet/dry ratio and expression levels of inflammatory cytokines). The beneficial effects of EGCG on preventing inflammatory lung injuries were in a concentration-dependent manner. Meanwhile, higher expression levels of mtDNA and inflammatory cytokines were observed in the media of cyclic stretched cell culture compared to those in the control group (p < 0.05). Furthermore, intra-tracheal administration of mtDNA in rats could lead to a marked increase of local inflammatory cytokines and subsequent inflammatory lung injuries (p < 0.05). And by adding mtDNA into the cell culture, higher level of inflammatory cytokines in the media was detected (p < 0.05). EGCG also showed preventive effects on inflammatory responses on a concentration-dependent manner (p < 0.05). CONCLUSION: The increased expression level of mtDNA and subsequent inflammatory cytokines overproduction may play an important role in the development of VILI. EGCG may be a potential novel therapeutic candidate for protection against VILI by inhibiting the local release of mtDNA.

Mitochondrial DNA­induced inflammatory damage contributes to myocardial ischemia reperfusion injury in rats: Cardioprotective role of epigallocatechin.

Inflammation serves an important role in the pathogenesis of myocardial ischemia/reperfusion (I/R) injury. Fragments of endogenous damaged­associated molecular patterns, recently identified as mitochondrial DNA (mtDNA), have been proven to be a potent pro­inflammatory mediator. Epigallocatechin­3­gallate (EGCG) is able to regulate the expression levels of a series of inflammatory cytokines. However, the involvement of endogenous mtDNA in EGCG­regulated inflammatory activities in the context of myocardial I/R injury remains to be elucidated. The present study was designed to investigate the role of mtDNA in EGCG­mediated myocardial protection in a rat I/R model. Significant positive correlations between elevated plasma mtDNA copy numbers and the expression levels of tumor necrosis factor (TNF) and interleukins (IL)­6 and ­8 were observed in the myocardial tissue following an I/R injury (P<0.05). However, EGCG administered prior to reperfusion was able to effectively downregulate the expression levels of plasma mtDNA, TNF and IL­6 and ­8 in the myocardial tissue following an I/R injury (P<0.05). Limited infarct size, reduced severity of myocardial injury and decreased incidence of ventricular arrhythmia were observed in the EGCG­treated group. However, the beneficial effects of EGCG in preventing myocardial I/R injury may be eliminated by a specific phosphoinositide­3­kinase (PI3K) inhibitor. These results suggested that EGCG­mediated cardioprotective effects may be achieved by inhibiting the release of mtDNA from damaged mitochondria and that this protection was at least in part dependent on the PI3K/RAC­α serine/threonine­protein kinase associated signaling pathway.

[Epigallocatechin-3-gallate Attenuates Myocardial Reperfusion Injury in Rats Through Activation of PI3K/Akt Signaling Pathway].

OBJECTIVE: This study was designed to investigate whether epigallocatechin-3-gallate (EGCG) postconditioning protects the heart against ischemic-reperfusion injury (IRI), and to explore its potential mechanisms in a rat model. METHODS: Male Wistar rats were subjected to myocardial ischemia (30 min) and reperfusion (up to 2 h) and the rats were divided into sham group (SO) group, ischemia-reperfusion (I/R) model group and EGCG group. EGCG group were treated with EGCG (10 mg/kg) via intravenous infusion 5 min before reperfusion. Electrocardiogram were applied to record ventricular arrhythmia frequency. The severity of myocardial injury [serum level of lactate dehydrogenase (LDH) and creatine kinase (CK), hematoxylineosin (HE) staining] and ventricular arrhythmia, and the serum levels of inflammatory cytokines [tumor necrosis factor-α (TNF-α), interleukins-6 (IL-6) and IL-8] were assessed with ELISA, electrocardiogram and Western blot respectively. RESULTS: EGCG given before reperfusion could effectively reduce the serum level of LDH and CK and the incidence of ventricular arrhythmia (P < 0.05, respectively), improved the pathological damage. Meanwhile, EGCG could down-regulate the expression levels of TNF-α, IL-6, IL-8 in the myocardial tissue after IRI (P < 0.05, repectively). The expression levels of p-p85 and p-Akt in the EGCG group were significantly up-regulated compared to those in I/R group (P < 0.05, repectively). CONCLUSION: EGCG-related anti-inflammatory action could attenuate rat myocardial IRI and this cardioprotective effect might be activated through the PI3K/Akt pathway.

[Mechanisms for reversal of pulmonary hypertension by rapamycin in rats].

OBJECTIVE: To investigate the effects of rapamycin (RAP) on pulmonary hypertension (PH) in rats, and to provide new insights into medication selection for the clinical treatment of PH. METHODS: Fifty male Sprague-Dawley rats were randomly divided into blank control, PH model, solvent control, RAP 1, and RAP 2 groups. A rat model of PH was induced by left pneumonectomy (PE) and monocrotaline (MCT). At 5 days after PH model establishment, the solvent control group and the RAP 1 group received an intramuscular injection of solvent and RAP, respectively. At 35 days after PH model establishment, the RAP 2 group received an intramuscular injection of RAP. The mean pulmonary artery pressure (mPAP) and the right ventricle/left ventricle plus septum weight ratio (RV/LV+S) were measured in each group. Histopathological changes in the right lung were evaluated by hematoxylin-eosin (HE) staining. The relative expression of alpha-smooth muscle actin (α-SMA) and smooth muscle protein 22-alpha (SM22α) in each group was determined using real-time PCR. RESULTS: At 35 days after surgery, the PH model and the solvent control groups had significantly higher mPAP and RV/LV+S than the blank control group, while the RAP 1 and the RAP 2 groups had significantly lower mPAP than the solvent control group (P<0.05). The RV/LV+S in the RAP 1 group was significantly lower than that in the solvent control group (P<0.05); however, there was no significant difference in RV/LV+S between the RAP 2 and the solvent control groups (P>0.05). HE staining in the right lung showed the substantially thickened pulmonary artery wall and narrowed arterial lumen in the PH model and the solvent control groups compared with the blank control group. Different degrees of reversal of the pulmonary artery wall thickening were observed after RAP administration. The results of real-time PCR revealed that the relative expression of α-SMA and SM22α in the PH model and the solvent control groups was significantly lower than in the blank control group, while the relative expression of α-SMA and SM22α in the RAP 1 and the RAP 2 groups was significantly higher than in the solvent control group (P<0.05). CONCLUSIONS: RAP can reverse the increase in pulmonary artery pressure and the right ventricular hypertrophy probably by regulation of the phenotypic conversion of vascular smooth muscle cells.