Protective role of arachidonic acid against diabetic myocardial ischemic injury: a translational study of pigs, rats, and humans.

AIM: Patients with diabetes mellitus have poor prognosis after myocardial ischemic injury. However, the mechanism is unclear and there are no related therapies. We aimed to identify regulators of diabetic myocardial ischemic injury. METHODS AND RESULTS: Mass spectrometry-based, non-targeted metabolomic approach was used to profile coronary sinus blood from diabetic and non-diabetic Bama-mini pigs at 0.5-h post coronary artery ligation. Six metabolites had a |log2 (Fold Change)|> 1.3. Among them, the most changed is arachidonic acid (AA), levels of which were 32 times lower in diabetic pigs than in non-diabetic pigs. The AA-derived products, PGI2 and 6-keto-PGF1α, were also significantly reduced. AA treatment of cultured cardiomyocytes protected against cell death by 30% at 48 h of high glucose and oxygen deprivation, which coincided with increased mitophagic activity (as indicated by increased LC3II/LC3I, decreased p62 and increased parkin & PINK1), improved mitochondrial renewal (upregulation of Drp1 and FIS1), reduced ROS generation and increased ATP production. These cardioprotective effects were abolished by PINK1(a crucial mitophagy protein) knockdown or the autophagy inhibitor 3-Methyladenine. The protective effect of AA was also inhibited by indomethacin and Cay10441, a prostacyclin receptor antagonist. Furthermore, diabetic Sprague Dawley rats were subjected to coronary ligation for 40 min and AA treatment (10 mg/day per animal gavaged) decreased myocardial infarct size, cell apoptosis index, inflammatory cytokines and improved heart function. Scanning electron microscopy showed more intact mitochondria in the border zone of infarcted myocardium in AA treated rats. Lastly, diabetic patients after myocardial infarction had lower plasma levels of AA and 6-keto-PGF1α and reduced cardiac ejection fraction, compared with non-diabetic patients after myocardial infarction. Plasma AA level was inversely correlated with fasting blood glucose. CONCLUSIONS: AA protects against diabetic ischemic myocardial damage by promoting mitochondrial autophagy and renewal, which is related to AA derived PGI2 signaling. AA may represent a new strategy to treat diabetic myocardial ischemic injury.

Safety and Effectiveness Outcomes of a Novel Automated Titanium Suture Fastener Device Applied for Heart Valve Surgery in an Ovine Model.

OBJECTIVE: This study was designed to evaluate the operability, effectiveness, and safety of the automated titanium suture fastener in a preclinical ovine model in comparison with manual tying in a mitral valve annuloplasty ring implantation surgery. METHODS: Eighteen adult Small-tailed Han sheep were prepared for the surgery of mitral valve annuloplasty ring implantation through lateral thoracotomy under cardiopulmonary bypass (CBP). A total of 12 stitches were performed to secure an annuloplasty ring, with 6 stitches done with the automated fastener and the other 6 by manual tying. The knotting time for the automated fastener or manual tying was recorded, respectively. The firmness of knots, mitral valve integrity, biocompatibility, thrombosis, local reactions, and other aspects were also compared at follow-up time (Days 30, 60, 90, and 180). RESULTS: Of the 18 sheep, 16 survived to the designated endpoints and were enrolled for further analysis. Compared with the control group, the knotting time was significantly reduced with the automated fastener (p < 0.01). All the annuloplasty rings were tightly secured by 6 fastener clips and 6 hand-made knots without any disengagement or displacement. All the mitral valves were intact without any defect, stenosis, prolapse, valve insufficiency, or perforation. Endothelialization was comparable between the two groups by Day 60. Small red thrombi formed at the thread end of the suture in both groups. No thrombus was found on the surface of the titanium clip. All the thrombi were within the acceptable range for the antithrombotic property. Thrombosis showed no significant difference by Day 60. No significant differences in the inflammatory response and pathological lesions were observed by Day 60. One case of diffuse renal infarction (area ratio = 20%) and 1 case of small focal renal infarction (area ratio < 5%) were caused by thromboembolism. CONCLUSIONS: The automated fastener significantly shortened the procedure time of tying knots for the implantation of the annuloplasty ring in the ovine model, with comparable safety and effectiveness as manual tying.

[Establishment of acute myocardial infarction model in diabetic miniature pigs through video-assisted thoracoscopic surgery].

OBJECTIVE: To explore a new method of establishing acute myocardial infarction model in diabetic miniature pigs through video-assisted thoracoscopic surgery (VATS). METHODS: Seven normal miniature pigs and 7 diabetic miniature pigs underwent VATS by selectively ligating left anterior descending coronary artery and then were evaluated through serology, imaging and histology. RESULTS: The serum levels of troponin (cTni) and myoglobin (MYO) in both groups significantly increased by over 10 folds of upper normal limit after VATS. Echocardiography, MRI and histopathologic analysis showed that the affected myocardial parts were apex, left ventricular wall and interventricular septum cosco section. But heart function of diabetic miniature pigs were relatively lower; infarction area/area-at-risk ratio higher (18.4% ± 5.5% vs 5.3% ± 3.9%, P = 0.03) , myocardial infarction through-wall degree more severe. These were in accordance with poor ischemic tolerance in diabetic myocardia. CONCLUSION: VATS is a safe and effective method for establishing AMI model in diabetic miniature pigs.