Cardioprotective Effects of VCP Modulator KUS121 in Murine and Porcine Models of Myocardial Infarction

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KUS121 was developed to selectively inhibit the adenosine triphosphatase activity of valosin-containing protein without affecting other cellular functions of valosin-containing protein.

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KUS121 preserved adenosine triphosphate levels, reduced endoplasmic reticulum stress, and suppressed cell death in H9C2 rat cardiomyoblast cells, treated with tunicamycin or hydrogen peroxide, or cultured in glucose-free medium.

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In murine ischemia and reperfusion injury models, KUS121 treatment after reperfusion attenuated the infarcted size and preserves cardiac function by maintaining adenosine triphosphate levels and reducing ER stress.

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In porcine ischemia and reperfusion injury models, intracoronary administration of KUS121 also attenuated the infarcted area in a dose-dependent manner.

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These results indicated that KUS121 is a promising novel therapeutic agent for myocardial infarction.

No effective treatment is yet available to reduce infarct size and improve clinical outcomes after acute myocardial infarction by enhancing early reperfusion therapy using primary percutaneous coronary intervention. The study showed that Kyoto University Substance 121 (KUS121) reduced endoplasmic reticulum stress, maintained adenosine triphosphate levels, and ameliorated the infarct size in a murine cardiac ischemia and reperfusion injury model. The study confirmed the cardioprotective effect of KUS121 in a porcine ischemia and reperfusion injury model. These findings confirmed that KUS121 is a promising novel therapeutic agent for myocardial infarction in conjunction with primary percutaneous coronary intervention.

Iatrogenic Intramural Hematoma Identified by Intravascular Ultrasound Following Selective Angiography of the Left Internal Mammary Artery

This case reports on iatrogenic intramural hematoma of the left internal mammary artery (LIMA) identified on intravascular ultrasound. This case illustrates the importance of intravascular imaging to identify the presence and extent of an intraluminal hematoma that is not visualized on angiography and that was the cause of ischemic symptoms following LIMA injection. (Level of Difficulty: Advanced.)

The effect of DPP-4-protected GLP-1 (7-36) on coronary microvascular function in obese adults

Objective

Glucagon-like-peptide-1 (GLP-1) receptor analogues have been shown to reduce cardiovascular events in patients with type 2 diabetes. However, the mechanism behind is still unknown. The aim of the study was to investigate the effect of intact GLP-1 (7-36) on coronary microcirculation in overweight adults.

Design and methods

A double-blinded randomized cross-over study was performed, with 12 overweight participants. Effects of intact GLP-1 (7-36) infusion were compared with a saline infusion on separate days. A DPP-4 inhibitor was administered to block degradation of intact GLP-1 (7-36) to the GLP-1 metabolite (9-36). Coronary microcirculation was assessed by Doppler coronary flow velocity reserve (CFVR) before and after 2 h of infusion. Peripheral endothelial function was assessed by flow mediated dilation (FMD) before and after one hour of infusion.

Results

CFVR was 3.77 ± 1.25 during GLP-1 infusion and 3.85 ± 1.32 during saline infusion, endothelial function was 16.3 ± 15.5 % during GLP-1 infusion and 7.85 ± 7.76 % during saline infusion. When adjusting for baseline values no significant differences in CFVR (ΔCFVR 0.38 ± 0.92 vs. ΔCFVR 0.71 ± 1.03, p = 0.43) and no difference in peripheral endothelial function (ΔFMD 7.34 ± 11.5 % vs. ΔFMD -1.25 ± 9.23%, p = 0.14) was found.

Conclusions

We found no effect of intact GLP-1 (7-36), protected from DPP4 mediated degradation on coronary microcirculation in overweight adults.

Chest pain CT in the emergency department: Watch out for the myocardium

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Hypodense myocardium (HM) can be observed often in chest pain CT examinations of patients presenting to the emergency department with chest pain.

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There is benefit when the myocardium is also analyzed for the presence of HM, even when the heart and coronary arteries were not specifically asked-for.

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Sensitivity, specificity, PPV and NPV for the detection of acute myocardial infarction by assessing HM was 52%, 100%, 100% and 95% respectively.

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Assessment of hypodense myocardium may increase the diagnostic confidence in ambiguous coronary findings in chest pain CT.

Rationale and Objectives

To evaluate the frequency and relevance of hypodense myocardium (HM) encountered in patients undergoing chest-pain CT in the emergency department (ED).

Material and Methods

In this IRB-approved retrospective study, ECG-gated chest-pain CT examinations of 300 consecutive patients (mean age 60 ± 17 years) presenting with acute chest-pain to our ED were evaluated. Once ST-segment elevation infarction was excluded, chest-pain CT including the coronary arteries (rule-out acute coronary syndrome (ACS), pulmonary embolism (PE) and acute aortic syndrome (AAS): chest-pain CT_coronary, n = 121) or not including the coronary arteries was performed (rule-out PE and AAS: chest-pain CT_{w/o coronary}, n = 179). Each myocardial segment was assessed for the presence of HM; attenuation was measured and compared to normal myocardium.

Results

HM was identified in 27/300 patients (9%): 12/179 in chest-pain CT_{w/o coronary} (7%) and 15/121 in chest-pain CT_coronary (12%). Mean attenuation of HM (40 ± 17 HU) was significantly lower than that of healthy myocardium (103 ± 18 HU, p < 0.001), with a mean difference of 61 ± 19 HU. In 15/27 patients (55.6%) with HM, the final diagnosis was acute MI, and in the remaining 12/27 patients (44.4%) previous MI was found in the patients’ history. Chest-pain CT_{w/o coronary} identified HM in 10/15 patients (66.6%) with a final diagnosis of acute MI.

Conclusion

HM indicating acute MI are often encountered in chest pain CT in the ED, also in chest-pain CT_{w/o coronary} when MI is not suspected. This indicates that the myocardium should always be analyzed for hypodense regions even when MI not suspected.

Intravenous miR-144 reduces left ventricular remodeling after myocardial infarction

MicroRNA-144 is a cytoprotective miRNA. Our previous study showed that miR-144 provides potent acute cardioprotection in an ischemia/reperfusion injury model. This study was performed to further assess whether miR-144 improves post-MI remodeling in a non-reperfused myocardial infarction (MI) model. C57BL/6 mice were subjected to MI by permanent left anterior descending artery (LAD) ligation. miR-144 was delivered by intravenous injections of 8 mg/kg, 16 mg/kg, or 32 mg/kg at day 0, day 1, day 3, and then a similar dose given once every 3 days, until day 28 after MI. Cardiac function was evaluated using echocardiography. At the end of the study, heart function was also evaluated using a pressure volume catheter. The percentage of the length of the infarct scar on the left ventricle (LV) circumferential length was calculated for heart each section. The miR-144 KO mice showed a worse heart failure phenotype with ventricular dilation and impaired contractility after LAD ligation. Ischemia decreased miR-144 levels, and the miR-144 level was restored to baseline by administration of intravenous miR-144. Cy3-labeled miR-144 was localized to the infarct and border zone, and was taken up by cardiomyocytes and macrophages. In miR-144-treated groups, at 28 days MI size was significantly reduced, and cardiac function was improved [LV fractional shortening, end-systolic volume (µL), end-diastolic volume (µL), ejection fraction (%), dP/dt max (mmHg/s), dP/dt min (mmHg/s), Tau (ms)], compared with controls (p < 0.01). This beneficial effect was associated with reduced border zone fibrosis, inflammation and apoptosis, these effects were associated with significant changes in autophagy signaling. Intravenous miR-144 has potent effects on post-MI remodeling. These findings suggest that miR-144 has potential as a therapeutic agent after MI.

Influence of collaterals on the left ventricular end-diastolic pressure and serum NT-proBNP levels in patients with coronary chronic total occlusion

Objective

Although numerous studies have shown the protective effects of the well-developed coronary collaterals on left ventricular functions, the relationship between collateral grade and left ventricular end diastolic pressure has not been studied in chronic total occlusion patients. Also, there are conflicting data on the effect of collaterals on NT-proBNP levels. The aim of our study was to evaluate the relationship between coronary collateral circulation and left ventricular end diastolic pressure and NT-proBNP levels in chronic total occlusion patients.

Methods

Study group was retrospectively selected from the patients who had undergone coronary angiography at our hospital between June 2011 and March 2013. Clinical, biochemical, angiographic and hemodynamic data of 199 consecutive patients having at least one totally occluded major epicardial coronary artery were evaluated. Coronary collateral circulation was graded according to Rentrop classification. While Rentrop grade 3 was defined as well-developed, all the remaining collateral grades were regarded as poor collaterals.

Results

Overall 87 patients were found to have good collaterals and 112 patients had poor collaterals. There was no significant difference between the patients with well- or poorly developed coronary collaterals with regard to left ventricular end diastolic pressure (16.84 ± 5.40 mmHg vs 16.10 ± 6.09, respectively, p = 0,632) and log NT-proBNP (2.46 ± 0.58 vs 2.59 ± 0.76, respectively, p = 0,335).

Conclusion

In patients with coronary chronic total occlusion even well-developed coronary collaterals are not capable of protecting the rise of left ventricular end diastolic pressure and NT-proBNP levels which are reliable markers of the left ventricular dysfunction.

Touch-free measurement of body temperature using close-up thermography of the ocular surface

In experimental animal research body temperature (BT) is measured for the objective determination of an animals’ physiological condition. Invasive, probe-based measurements are stressful and can influence experimental outcome. Alternatively BT can be determined touch-free from the emitted heat of the organism at a single spot using infrared thermometers [1]. To get visual confirmation and find more appropriate surfaces for measurement a hand-held thermal imager was equipped with a self-made, cheap, 3D-printable close-up lens system that reproducibly creates eight-time magnified thermal images and improves sensitivity. This setup was used to establish ocular surface temperature (OST), representing the temperature of the brain-heart axis, as a touch-free alternative for measurement of BT in mice, rats, rabbits and humans.OST measurement after isoflurane exposure and myocardial infarction (MI) experiments in mice revealed high physiological relevance and sensitivity, the possibility to discriminate between MI and sham operations in one hour and even long-term outcome-predictive capabilities of OST after MI. Summarized here we present:

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Self-made close-up lens for thermal imaging cameras for eight-time magnification

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Establishment of OST for touch-free determination of BT in rodents and humans

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Short- and long-term predictive capabilities of OST in experimental MI in mice.

Treatment strategies in the left main coronary artery disease associated with acute coronary syndromes

Significant left main coronary artery (LMCA) stenosis is not rare and reported 3 to 10% of patients undergoing coronary angiography. Unprotected LMCA intervention is a still clinical challenge and surgery is still going to be a traditional management method in many cardiac centers. With a presentation of drug eluting stent (DES), extensive use of IVUS and skilled operators, number of such interventions increased rapidly which lead to change in recommendation in the guidelines regarding LMCA procedures in the stable angina (Class 2a recommendation for ostial and shaft lesion and class 2b recommendation for distal bifurcation lesion). However, there was not clear consensus about the management of unprotected LMCA lesion associated with acute myocardial infarction (MI) with a LMCA culprit lesion itself or distinct culprit lesion of other major coronary arteries. Surgery could be preferred as an obligatory management strategy even in the high risk patients. With this review, we aimed to demonstrate treatment strategies of LMCA disease associated with acute coronary syndrome, particularly acute myocardial infarction (MI). In addition, we presented a short case series with LMCA lesion and ST elevated acute MI in which culprit lesion placed either in the left anterior descending artery or circumflex artery. We reviewed the current medical literature and propose simple algorithm for management.