Ischemic and postischemic conditioning of the myocardium in clinical practice: challenges, expectations and obstacles

Multifaceted involvements of Paneth cells in various diseases within intestine and systemically

Serving as the guardians of small intestine, Paneth cells (PCs) play an important role in intestinal homeostasis maintenance. Although PCs uniquely exist in intestine under homeostasis, the dysfunction of PCs is involved in various diseases not only in intestine but also in extraintestinal organs, suggesting the systemic importance of PCs. The mechanisms under the participation of PCs in these diseases are multiple as well. The involvements of PCs are mostly characterized by limiting intestinal bacterial translocation in necrotizing enterocolitis, liver disease, acute pancreatitis and graft-vs-host disease. Risk genes in PCs render intestine susceptible to Crohn’s disease. In intestinal infection, different pathogens induce varied responses in PCs, and toll-like receptor ligands on bacterial surface trigger the degranulation of PCs. The increased level of bile acid dramatically impairs PCs in obesity. PCs can inhibit virus entry and promote intestinal regeneration to alleviate COVID-19. On the contrary, abundant IL-17A in PCs aggravates multi-organ injury in ischemia/reperfusion. The pro-angiogenic effect of PCs aggravates the severity of portal hypertension. Therapeutic strategies targeting PCs mainly include PC protection, PC-derived inflammatory cytokine elimination, and substituting AMP treatment. In this review, we discuss the influence and importance of Paneth cells in both intestinal and extraintestinal diseases as reported so far, as well as the potential therapeutic strategies targeting PCs.

Endless Journey of Adenosine Signaling in Cardioprotective Mechanism of Conditioning Techniques: Clinical Evidence

Myocardial ischemic injury is a primary cause of death among various cardiovascular disorders. The condition occurs due to an interrupted supply of blood and vital nutrients (necessary for normal cellular activities and viability) to the myocardium, eventually leading to damage. Restoration of blood supply to ischemic tissue is noted to cause even more lethal reperfusion injury. Various strategies, including some conditioning techniques, like preconditioning and postconditioning, have been developed to check the detrimental effects of reperfusion injury. Many endogenous substances have been proposed to act as initiators, mediators, and end effectors of these conditioning techniques. Substances, like adenosine, bradykinin, acetylcholine, angiotensin, norepinephrine, opioids, etc., have been reported to mediate cardioprotective activity. Among these agents, adenosine has been widely studied and suggested to have the most pronounced cardioprotective effects. The current review article highlights the role of adenosine signaling in the cardioprotective mechanism of conditioning techniques. The article also provides an insight into various clinical studies that substantiate the applicability of adenosine as a cardioprotective agent in myocardial reperfusion injury.

Lung injury after cardiopulmonary bypass: Alternative treatment prospects

Although the lung injury caused by cardiopulmonary bypass (CPB) has been extensively investigated, the incidence and mortality of lung injury after CPB remain a prominent clinical problem. The poor outcome has been attributed to multifactorial etiology, including the systemic inflammatory response and ischemia reperfusion (I/R) injury during CPB. Lung injury after CPB is a complex pathophysiological process and has many clinical manifestations of mild to severe disease. Which is associated with prognosis. To alleviate this lung injury, interventions that address the pathogenesis are particularly important. This review summarizes the pathogenesis, mechanism and treatment options of lung injury after CPB, such as lung protection with intralipid.

Intralipid postconditioning in patients of cardiac surgery undergoing cardiopulmonary bypass (iCPB): study protocol for a randomized controlled trial

Background

Intralipid is a necessary fatty acid carrier that has been safely used as an energy supplier in the clinic. It has played an important role in rescuing the cardiac arrest caused by local anesthetic toxicity. In recent years, experimental studies have shown that intralipid postconditioning (ILPC) could reduce myocardial ischemic/reperfusion (I/R) injuries. Our research group has innovatively conducted a pilot randomized controlled trial (RCT), and the results showed that ILPC could reduce the release of cTnT and CK-MB, biomarkers of myocardial I/R injury, in valve replacement surgery. However, the potential effects of ILPC on the clinical outcome of adult cardiac surgery patients are unclear. Intralipid postconditioning in patients of cardiac surgery undergoing cardiopulmonary bypass (iCPB) trial is aimed to further study whether ILPC could improve short-term and long-term clinical outcome, as well as cardiac function in adult cardiac surgery patients.

Methods

The iCPB trial is an ongoing, single-center, prospective, double-blinded, large sample RCT. In total, 1000 adults undergoing cardiac surgery will be randomly allocated to either the ILPC group or the control group. The intervention group received an intravenous infusion of 2 mL/kg of 20% intralipid (medium-chain and long-chain fat emulsion injection C6~C24, Pharmaceutical) within 10 min before aortic cross-unclamping, and the control group received an equivalent volume of normal saline. The primary endpoints are complex morbidity of major complications during hospitalization and all-cause mortality within 30 days after surgery. The secondary endpoints include (1) all-cause mortality 6 months and 1 year postoperatively; (2) the quality of life within 1 year after surgery, using the QoR-15 questionnaire; (3) the postoperative cardiac function evaluated by LVEF, LVEDS, and LVEDD, and the myocardial injury evaluated by CK-MB, cTnT, and BNP; and (4) short-term clinical outcomes during hospitalization and total cost are also detailed evaluated.

Discussion

The iCPB trial is the first to explore ILPC on the clinical outcome of adult cardiac surgery patients. The results are expected to provide potential evidences about whether ILPC could reduce the morbidity and mortality and improve the cardiac function and quality of life. Therefore, the results will provide a rationale for the evaluation of the potentially clinically relevant benefit of intralipid therapy.

Trial registration

Chictr.org.cn ChiCTR1900024387. Prospectively registered on 9 July 2019.

[Clinical and laboratory features of primary acute myocardial infarction in patients with obstructive and non-obstructive coronary atherosclerosis]

According to the literature, 40-60% of patients with acute myocardial infarction (AMI) have obstructive multivessel coronary artery disease (CA) and 8.8% of patients have non-obstructive CA lesions. And it is around these two groups of patients that there are active discussions and disputes regarding the choice of optimal treatment tactics and further prognosis. The aim of the study was to study clinical and laboratory features of development and course of primary AMI in patients with multi-and single-vessel obstructive lesion of the CA compared with patients with non-obstructive CA lesions. Methods. The study has included patients hospitalized "through the ambulance channel" in the Department of cardiac intensive care of municipal clinical hospital named after S. S. Yudin Moscow with a diagnosis "primary acute myocardial infarction", ACS with and without ST segment elevation, unstable angina in 2015-2016. The diagnosis of acute myocardial infarction (AMI) was established at the hospital stage according to the criteria of the "Third universal definition of myocardial infarction" in 2012. The study included 1240 patients who underwent coronary angiography (CAG) no later than 12 hours from the time of admission. The first group (comparison group) consisted of patients with AMI and the first detected multivessel obstructive atherosclerotic lesion of CA (664 patients), the second (interest group) consisted of patients with AMI and non-obstructive atherosclerotic lesion of CA (96 patients) meeting the MINOCA criteria. The third group consisted of patients with single-vessel obstructive lesion and complete acute occlusion of the CA (272 patients). Patients with hemodynamically significant lesions of the left CA trunk were not included in the study. The clinical and laboratory features of the course of acute primary myocardial infarction in patients with obstructive and non-obstructive coronary atherosclerosis were studied. The generally accepted statistical processing methods were used. A year after discharge from the hospital, 727 patients (468 patients from the 1st group, 78 from the 2nd group, 181 from the 3rd group) were interviewed by means of a structured telephone survey about the course of the disease (collection of medical history). The median follow-up was 12 months. (interquartile range 11-13 months). The endpoints were: re-hospitalization for any reason, re-coronary event, death. The received answers are entered into questionnaires and statistically processed. Results and conclusions. In patients with AMI and non-obstructive atherosclerotic CA lesion, pain behind the sternum is observed one and a half times less often (54.2%) than in patients with obstructive CA lesion (MOAPCA 86.1%, OAPCA 89.7%) and the cardiac co duction system is almost three times more likely to be affected ( 30% versus 8.4% and 12%). Only 12.5% of patients in this group had an abnormal Q wave (Q - myocardial infarction) on the ECG, therefore, a smaller volume of myocardial damage and a lower level of troponin than in patients of groups 1 and 3. During the first year after the development of AMI, patients with obstructive coronary atherosclerosis did not experience repeated coronary events, there were no indications for conducting CAG, PCI or CABG, in contrast to patients with obstructive lesion of CA. For multivascular obstruction (group 1), PCI was performed in 9.6% of patients and 3.8% of CABG. PCI was performed in group 3 with obstructive single-vessel lesion of CA in 7.7% of patients. In patients with AMI and obstructive single-vessel atherosclerotic lesion of CA (group 3), two and a half times less often (9.1%) myocardial reperfusion injury is observed, while in patients with multivascular obstructive CA defeat, this syndrome was observed in 21.3%.

[Effect of Myocardial Reperfusion on Ischemic Mitral Regurgitation in Patients with Acute Myocardial Infarction]

BACKGROUND

During the restoration of blood flow in the ischemic area of the myocardium, viable cardiomyocytes are damaged over a few minutes of tissue reperfusion (reperfusion myocardial damage). It is known that ischemic mitral regurgitation (IMR) develops in 11-19 % of patients who have undergoing percutaneous coronary intervention (PCI) in symptomatic coronary heart disease (CHD). To present day, the influence of myocardial reperfusion on IMR in patients with acute myocardial infarction (AMI) is not fully understood.

OBJECTIVE

To study dynamics of quantitative indicators of IMR in patients with AMI after myocardial reperfusion.

MATERIALS AND METHODS

We included in this study 68 patients with AMI and IMR aged 36-79 years, who were hospitalized in cardiac intensive care unit of the Moscow S. S. Yudin hospital in 2016. All patients before and on the 7th day after PCI underwent doppler echocardiography study with calculation of quantitative parameters of IMR and index of local contractility (ILC) of the left ventricle (LV).

RESULTS

Three groups of patients were identified based on the analysis of the dynamics of quantitative parameters of IMR after myocardial reperfusion: group 1 - patients who had a decrease in IMR (n=23, 33.8 %), group 2 - patients with increase of IMR (n=28, 41.1 %), group 3 - patients with unchanged IMR (n=17, 25.1 %). The study of systolicLV function in all patients before PCI revealed moderately decreased ejection fraction (EF) (mean 49.05±1.19 %). On day 7 after myocardial reperfusion in group 2 we detected significant increases of end-diastolic volume (EDV), end-systolic volume (ESV), and the volume of the left atrium (LA), while in groups 1 and 3 these indexes remained unchanged. LV ILC did not differ between three groups, both at admission and on day 7 after reperfusion (p>0.05). There was no correlation between severity of IMR and ILC (correlation coefficient 0.24).

CONCLUSION

Dynamics of quantitative parameters of IMR in 7 days after myocardial reperfusion in patients with AMI without endogenous and drug protection of the myocardium from reperfusion injury was multidirectional. IMR decreased in 33.8, increased in 41.1 and did not change in 25.1 % of patients. Systolic function and LV ILC underwent no significant dynamics.

Adenosine as a Multi-Signalling Guardian Angel in Human Diseases: When, Where and How Does it Exert its Protective Effects?

The importance of adenosine for human health cannot be overstated. Indeed, this ubiquitous nucleoside is an integral component of ATP, and regulates the function of every tissue and organ in the body. Acting via receptor-dependent and -independent mechanisms [the former mediated via four G-protein-coupled receptors (GPCRs), A1, A2A, A2B, and A3,], it has a significant role in protecting against cell damage in areas of increased tissue metabolism, and combating organ dysfunction in numerous pathological states. Accordingly, raised levels of adenosine have been demonstrated in epilepsy, ischaemia, pain, inflammation, and cancer, in which its behaviour can be likened to that of a guardian angel, even though there are instances in which overproduction of adenosine is pathological. In this review, we condense the current body of knowledge on the issue, highlighting when, where, and how adenosine exerts its protective effects in both the brain and the periphery.

Confounders of Cardioprotection by Remote Ischemic Preconditioning in Patients Undergoing Coronary Artery Bypass Grafting

OBJECTIVES

Remote ischemic conditioning (RIC) by repetitive blood pressure cuff inflation/deflation around a limb provides cardioprotection in patients undergoing coronary artery bypass grafting (CABG). Cardioprotection is confounded by risk factors, comorbidities and comedications. We aimed to identify confounders that possibly attenuate the protection provided by RIC.

METHODS

In a retrospective analysis of our single-center, randomized, double-blind trial of patients undergoing elective CABG with/without RIC prior to ischemic cardioplegic arrest, we analyzed demographics, medications and intraoperative variables. The primary end point was myocardial injury, as reflected by the area under the curve for serum troponin I (TnI) from baseline to 72 h after surgery.

RESULTS

In models with 2 independent variables and in the multivariate analysis, age and aortic cross-clamp time impacted on TnI release. Subgroup analyses confirmed RIC-induced protection in all age tertiles. There was no protection with an aortic cross-clamp time ≤56 min (RIC/control = 1.026 not significant), but there was protection with 57-75 min (RIC/control = 0.757; p = 0.0348) and ≥76 min (RIC/control = 0.735; p = 0.0277). Gender, β-blockers, statins, angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) and intraoperative nitroglycerine did not impact on TnI release.

CONCLUSION

Age, gender, β-blockers, statins, ACE inhibitors, ARBs and intraoperative nitroglycerine have no significant impact on RIC-induced cardioprotection during CABG. However, greater myocardial ischemia/reperfusion injury at longer cross-clamp time facilitates the detection of protection by RIC.

Cardioprotection by remote ischemic conditioning: Mechanisms and clinical evidences

In remote ischemic conditioning (RIC), several cycles of ischemia and reperfusion render distant organ and tissues more resistant to the ischemia-reperfusion injury. The intermittent ischemia can be applied before the ischemic insult in the target site (remote ischemic preconditioning), during the ischemic insult (remote ischemic perconditioning) or at the onset of reperfusion (remote ischemic postconditioning). The mechanisms of RIC have not been completely defined yet; however, these mechanisms must be represented by the release of humoral mediators and/or the activation of a neural reflex. RIC has been discovered in the heart, and has been arising great enthusiasm in the cardiovascular field. Its efficacy has been evaluated in many clinical trials, which provided controversial results. Our incomplete comprehension of the mechanisms underlying the RIC could be impairing the design of clinical trials and the interpretation of their results. In the present review we summarize current knowledge about RIC pathophysiology and the data about its cardioprotective efficacy.