Effect of glucose-insulin-potassium infusion on plasma free fatty acid concentrations in patients undergoing primary percutaneous coronary intervention for ST-elevation myocardial infarction

Protein lysine acetylation does not contribute to the high rates of fatty acid oxidation seen in the post-ischemic heart

High rates of cardiac fatty acid oxidation during reperfusion of ischemic hearts contribute to contractile dysfunction. This study aimed to investigate whether lysine acetylation affects fatty acid oxidation rates and recovery in post-ischemic hearts. Isolated working hearts from Sprague Dawley rats were perfused with 1.2 mM palmitate and 5 mM glucose and subjected to 30 min of ischemia and 40 min of reperfusion. Cardiac function, fatty acid oxidation, glucose oxidation, and glycolysis rates were compared between pre- and post-ischemic hearts. The acetylation status of enzymes involved in cardiac energy metabolism was assessed in both groups. Reperfusion after ischemia resulted in only a 41% recovery of cardiac work. Fatty acid oxidation and glycolysis rates increased while glucose oxidation rates decreased. The contribution of fatty acid oxidation to ATP production and TCA cycle activity increased from 90 to 93% and from 94.9 to 98.3%, respectively, in post-ischemic hearts. However, the overall acetylation status and acetylation levels of metabolic enzymes did not change in response to ischemia and reperfusion. These findings suggest that acetylation may not contribute to the high rates of fatty acid oxidation and reduced glucose oxidation observed in post-ischemic hearts perfused with high levels of palmitate substrate.

Effect of preinitiated glucose-insulin-potassium strategy for patients with undergoing planned percutaneous coronary intervention: a systematic review and meta-analysis

OBJECTIVES

Whether the glucose-insulin-potassium (GIK) should be used as an adjuvant therapy for ischaemic myocardial disease remains controversial nowadays reperfusion era. This meta-analysis aimed to assess the effects of preinitiated GIK for patients undergoing planned percutaneous coronary intervention (PCI).

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Web of science, MEDLINE, Embase, Cochrane Library and ClinicalTrials.gov were searched through 27 November 2022.

ELIGIBILITY CRITERIA

Only randomised controlled trials involving participants preinitiated with GIK or placebo before planned PCI were included.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers used standardised methods to search, screen and code included trials. Risk of bias was assessed with the Cochrane tool. Pooled analysis was conducted using random or effects models according to the heterogeneity. Subgroup analyses were carried out for dosage of GIK and if with ongoing myocardial ischaemia.

RESULTS

13 randomised controlled trials (RCTs) including 3754 participants were evaluated. We found patients preconditioned with GIK before PCI showed a significant increase in Thrombolysis in Myocardial Infarction 3 flow events after angioplasty (OR 1.59, 95% CI 1.03 to 2.46, p=0.04), also revealed improved in-hospital left ventricular ejection fraction (weighed mean difference, WMD 1.62, 95% CI 0.21 to 3.03, p=0.02) and myocardial salvage index (WMD 0.09, 95% CI 0.01 to 0.16, p=0.03). Nevertheless, no benefit was observed in all-cause mortality neither on 30-day (OR 0.81, 95% CI 0.59 to 1.11, p=0.18) nor 6 months (OR 1.02, 95% CI 0.42 to 2.46, p=0.97). Furthermore, GIK intervention was associated with higher occurrences of complications such as phlebitis (OR 10.13, 95% CI 1.74 to 59.00, p=0.01) and hypoglycaemia (OR 10.43, 95% CI 1.32 to 82.29, p=0.03), but not hyperkalaemia (OR 9.36, 95% CI 0.50 to 175.27, p=0.13), liquid overload (OR 1.02, 95% CI 0.25 to 4.13, p=0.98) or in-hospital heart failure (OR 0.42, 95% CI 0.06 to 2.96, p=0.39).

CONCLUSIONS

Our study shows preconditioning GIK exhibits myocardial reperfusion and cardiac function benefits for patients planning to receive PCI intervention, while also some complications such as phlebitis and hypoglycaemia accompany.

PROSPERO REGISTRATION NUMBER

CRD42022326334.

Metformin regulates lipid metabolism in a canine model of atrial fibrillation through AMPK/PPAR-α/VLCAD pathway

Background

Atrial lipid metabolic remodeling is critical for the process of atrial fibrillation (AF). Abnormal Fatty acid (FA) metabolism in cardiomyocytes is involved in the pathogenesis of AF. MET (Metformin), an AMPK (AMP-activated protein kinase) activator, has been found to be associated with a decreased risk of AF in patients with type 2 diabetes. However, the specific mechanism remains unknown.

Methods

Fifteen mongrel dogs were divided into three groups: SR, ARP (pacing with 800 beats/min for 6 h), ARP plus MET (treated with MET (100 mg/kg/day) for two weeks before pacing). We assessed metabolic factors, speed limiting enzymes circulating biochemical metabolites (substrates and products), atrial electrophysiology and accumulation of lipid droplets.

Results

The expression of AMPK increased in the ARP group and significantly increased in the MET+ARP group comparing to the SR group. In the ARP group, the expressions of PPARα、PGC-1α and VLCAD were down-regulated, while the concentration of free fatty acid and triglyceride and the lipid deposition in LAA (left atrial appendage) increased. Moreover, AERP and AERPd have also been found abnormally in this process. Pretreatment with MET before receiving ARP reversed the alterations aforementioned.

Conclusions

The FA metabolism in LAA is altered in the ARP group, mainly characterized by the abnormal expression of the rate-limiting enzyme. Metformin reduces lipid accumulation and promotes β-oxidation of FA in AF models partially through AMPK/PPAR-α/VLCAD pathway. Our study indicates that MET may inhibit the FA lipid metabolic remodeling in AF.

C-Reactive protein reactions to glucose-insulin-potassium infusion and relations to infarct size in patients with acute coronary syndromes

Background

Some benefits of glucose-insulin-potassium (GIK) in patients with acute coronary syndromes (ACS) may be from an anti-inflammatory effect. The primary aim of this study was to assess the impact of GIK administration early in the course of ACS on inflammatory marker C-reactive protein (CRP) levels. A secondary aim was to investigate the association between CRP and 30-day infarct size.

Methods and Results

Retrospective analysis of participants with ACS randomly assigned to GIK or placebo for at least 8 h in the IMMEDIATE Trial biological mechanism cohort (n = 143). High sensitivity CRP (hs-CRP) was measured at emergency department presentation, and 6 and 12 h into infusion. Logarithmically transformed hs-CRP values at 12-hours were lower with GIK vs. placebo (mean =0.65 mg/L in GIK, 0.84 mg/L in placebo), with a marginal trend toward significance (P = 0.053). Furthermore, using mixed models of hs-CRP, time, and study group, there was a significant increase in hs-CRP levels over time, but the rate of change did not differ between treatment arms (P = 0.3). Multivariable analysis showed that an elevation in hs-CRP, measured at 12 h, was an independent predictor of 30-day infarct size (β coefficient, 6.80; P = 0.04) using sestamibi SPECT imaging.

Conclusions

The results of this study show no significant effect of GIK on hs-CRP. In addition our results show that in patients with ACS, hs-CRP measured as early as 12 h can predict 30-day infarct size.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-015-0153-7) contains supplementary material, which is available to authorized users.

Glucose-insulin therapy, plasma substrate levels and cardiac recovery after cardiac ischemic events

Introduction

The potential usefulness of glucose-insulin therapy relies to a large extent on the premise that it prevents hyperglycemia and hyperlipidemia following cardiac ischemic events.

Methods

In this review we evaluate the literature concerning plasma glucose and free fatty acids levels during and following cardiac ischemic events.

Results

The data indicate that hyperlipidemia and hyperglycemia most likely occur during acute coronary ischemic syndromes in the conscious state (e.g. acute myocardial infarction) and less so during reperfusion following CABG reperfusion. This is in accordance with observations that glucose-insulin therapy during early reperfusion post CABG may actually cause hypolipidemia, because substantial hyperlipidemia does not appear to occur during that stage of cardiac surgery.

Discussion

Considering recent data indicating that hypolipidemia may be detrimental for cardiac function, we propose that free fatty acid levels during reperfusion post CABG with the adjunct glucose-insulin therapy need to be closely monitored.

Conclusion

From a clinical point of view, a strategy directed at monitoring and thereafter maintaining plasma substrate levels in the normal range for both glucose (4–6 mM) and FFA (0.2–0.6 mM) as well as stimulation of glucose oxidation, promises to be the most optimal metabolic reperfusion treatment following cardiac ischemic episodes. Future (preclinical and subsequently clinical) investigations are required to investigate whether the combination of glucose-insulin therapy with concomitant lipid administration may be beneficial in the setting of reperfusion post CABG.

Effect of glucose-insulin-potassium (GIK) infusion on biomarkers of cardiovascular risk in ST elevation myocardial infarction (STEMI): insight into the failure of GIK

Glucose-insulin-potassium (GIK) infusion favourably affects several biomarkers associated with risk in the setting of myocardial infarction (MI). In the context of a recent trial demonstrating no benefit of GIK, we assessed the impact of GIK on inflammation, neurohormonal activation and myonecrosis in ST elevation myocardial infarction (STEMI). In a local substudy of an international randomised trial, 25 patients with STEMI were randomised to receive a 24-hour infusion of GIK vs. no GIK. C-reactive protein (hs-CRP), N-terminal pro-brain natriuretic peptide (NT-proBNP) and troponin T (TnT) were assayed at baseline and at 24 hours. The two groups were well matched for baseline characteristics and infarct location. There were no statistically significant differences at baseline or at 24 hours in levels of hs-CRP, NT-proBNP or cTnT, with similar and significant increases in all three biomarkers by 24 hours in both groups. In conclusion, GIK had no discernible effect on biomarkers associated with inflammation, neurohormonal activation or myonecrosis, three pathways associated with adverse outcomes in STEMI.

Insulin infusion therapy for myocardial infarction

In the last 10 years, there has been considerable interest in the administration of insulin as part of the management of myocardial infarction. This review examines the clinical trials of insulin infusion for myocardial infarction in the era of reperfusion therapy, and discusses the implications of the recently completed HI-5 (Hyperglycaemia: Intensive Insulin Infusion In Infarction) study. The clinical trials of insulin therapy for myocardial infarction can be divided into those with a primary aim of delivering insulin (insulin focus), and those with a primary aim of achieving tight glycaemic control (glycaemia focus). The evidence suggests that protocols with an insulin focus do not improve the outcome of myocardial infarction. However, the trials with a glycaemia focus are inconclusive and it remains possible that glycaemic control is beneficial.

Glucose, insulin and myocardial ischaemia

PURPOSE OF REVIEW

The importance of glucose metabolism and insulin therapy during myocardial ischaemia is increasingly being investigated. Insulin is used to achieve a tight glucose control or as part of glucose-insulin-potassium therapy. We have reviewed (1) the physiological and physiopathological consequences of hyperglycaemia focusing on potential machanisms of myocardial ischaemia, (2) the effects of insulin on vascular tone, on the release of free fatty acids, on inflammatory pathways, on the switch of energy source and on apoptosis, and (3) clinical data reporting the effects of intensive insulin therapy and glucose-insulin-potassium solutions during myocardial ischaemia and ischaemic heart failure.

RECENT FINDINGS

In addition to its known toxic cellular effects, hyperglycaemia increases the activity of inducible nitric oxide synthase and promotes inflammation. Conversely insulin exerts anti-inflammatory and anti-apoptotic effects. Glucose-insulin-potassium solutions could improve survival after acute myocardial infarction or after surgery, according to recent meta-analyses, but confirmation of these data is eagerly awaited.

SUMMARY

Hyperglycaemia is toxic, while insulin is beneficial during acute myocardial ischaemia. Some recent evidence confirms a substantial benefit of insulin administered either alone to achieve a tight glucose control or as a component of glucose-insulin-potassium therapy. Further research is needed to confirm that tendency and to define the threshold of tight glucose control.

Effect of glucose-insulin-potassium infusion on myocardial damage due to percutaneous coronary revascularization

Percutaneous coronary intervention has been known to cause myocardial damage as a result of microvascular dysfunction due to microembolization and microinfarction. Previous studies have shown that glucose-insulin-potassium (GIK) infusion decreases mortality in patients with acute myocardial infarction. Therefore, in this study, we aimed to investigate the effect of GIK infusion on myocardial damage due to percutaneous coronary revascularization. A total of 52 consecutive nondiabetic patients diagnosed with non-ST-elevation acute coronary syndrome and designated for elective percutaneous coronary intervention were randomized in a double-blind fashion into GIK and normal saline groups. GIK infusion (30% dextrose, 300 U insulin, and 60 mEq potassium chloride) at a dose of 1.5 ml/kg/hour was initiated 24 hours before the intervention and continuing during and until 1 hour after the intervention. Troponin I levels were recorded in venous blood samples before and 12 and 24 hours after the intervention. The increase in troponin I was significantly lower at 12 and 24 hours in the GIK group compared with those of the saline controls (p=0.022 and p=0.005, respectively). GIK infusion initiated 24 hours before coronary stenting for non-ST-elevation acute coronary syndrome resulted in less myocardial damage as determined by postprocedure troponin I levels.