Creatine phosphate and protection against reperfusion-induced arrhythmias in the rat heart

Prognostic Value of Creatine Phosphate and Inflammatory Markers for Mitral Valve Replacement: A Systematic Review and Meta-Analysis

Purpose

The prognosis of mitral valve replacement is an important clinical issue and may produce unexpected mortality rates if not properly addressed. The postoperative examination results have important prognostic implications. This study was designed to determine the prognostic value of phosphocreatine and inflammatory markers after mitral valve replacement.

Method

Comparison and analysis of the data obtained using SPSS software. The computer retrieved PubMed, Science Citation Index (SCI), Embase, VIP, CNKI, CBM, and Wanfang database and manually retrieved randomized controlled trials (RCTs) published at home and abroad on the central muscle protection role of creatine phosphate in heart valve replacement, and the search period was established until February 2018. Two random literature reviewers independently screened the literature and extracted data, using Review Manager (RevMan) (Computer program), version 5.3 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, 2014). RevMan software version 5.0 assesses the risk of bias for inclusion in studies. The software performs a meta-analysis of the obtained data.

Results

Ten RCTs with a total of 464 participants were enrolled. The meta-analysis results showed that (1) elevated creatine kinase levels often predict a better prognosis after mitral valve replacement (RR = 1.36, 95% CI: 1.22 to 1.52, P < 0.00001), (2) the creatine kinase isoenzyme level in the venous blood of the phosphocreatine group after 24 h of aortic blocking was significantly lower than that in the control group (SMD = -2.90, 95% CI: -5.19 to -0.60, P = 0.01), and (3) Troponin I levels were significantly lower in the intravenous creatine group than in the control group 24 h after opening of the aortic block (SMD = -1.49, 95% CI: -2.02 to -0.97,P < 0.00001).

Conclusions

Creatine phosphate and inflammatory factor have good predictive value for the prognosis of mitral valve replacement.

Creatine phosphate: pharmacological and clinical perspectives

Since the 1970s, extensive experimental and clinical research has demonstrated that relevant reductions of creatine phosphate (CrP) or phosphocreatine availability occur in a wide spectrum of pathophysiological situations. A decrease in intracellular concentrations of creatine (Cr) and CrP results in a hypodynamic state of cardiac and skeletal muscle pathology. Many experimental and clinical studies have evaluated the possibility to improve cardiac and skeletal muscle performance by exogenous administration of CrP. Furthermore, many experimental studies have shown that CrP may play two important roles in the regulation of muscle energetics and work. First, CrP maintains local adenosine triphosphate pools and stabilizes cellular membranes due to electrostatic interactions with phospholipids. The second mechanism decreases the production of lysophosphoglycerides in hypoxic hearts, protects the sarcolemma of cardiac cells against ischemic damage, decreases the frequency of arrhythmias, and increases post-ischemic recovery of contractile function. Recent research on CrP has demonstrated positive therapeutic results in various clinical applications. These benefits have been applied in several pathological conditions, such as heart failure, acute myocardial ischemia, chronic ischemic heart disease, cardiac surgery, skeletal muscle hypotonotrophy, and cerebral ischemia. This review describes the CrP shuttle, pathophysiological basis of the supplementation of CrP, and its therapeutic effects in multiple clinical conditions. The major aim is to summarize results of the intense research carried out over 40 years to provide evidence to support the adjunctive use of CrP in many pathological conditions that may target cellular energy impairment; thus, increasing energy metabolism.

Creatine and creatine kinase in health and disease--a bright future ahead?

Many links are reported or suspected between the functioning of creatine, phosphocreatine, the creatine kinase isoenzymes or the creatine biosynthesis enzymes on one hand, and health or disease on the other hand. The aim of the present book was to outline our current understanding on many of these links. In this chapter, we summarize the main messages and conclusions presented in this book. In addition, we refer to a number of recent publications that highlight the pleiotropy in physiological functions of creatine and creatine kinase, and which suggest that numerous discoveries on new functions of this system are still ahead of us. Finally, we present our views on the most promising future avenues of research to deepen our knowledge on creatine and creatine kinase. In particular, we elaborate on how state-of-the-art high-throughput analytical ("omics") technologies and systems biology approaches may be used successfully to unravel the complex network of interdependent physiological functions related to creatine and creatine kinase.

Hemodynamic effects of creatine phosphate in patients with congestive heart failure: a double-blind comparison trial versus placebo

BACKGROUND

The use of metabolic drugs effective in addition to conventional therapy represents a significant challenge in patients with left ventricular dysfunction.

HYPOTHESIS

The aim of this double-blind, placebo-controlled study was to investigate the hemodynamic effects of acute intravenous (i.v.) administration of creatine phosphate (CP) and of short-term treatment in patients with congestive heart failure (CHF) from ischemic heart disease (IHD) or dilated cardiomyopathy in addition to conventional therapy.

METHODS

We compared the hemodynamic effects of exogenous creatine phosphate (CP) and placebo in a double-blind, crossover design study in 13 hospitalized patients (12 men, 1 woman, mean age 52 +/- 8 years) with CHF. All patients were in New York Heart Association (NYHA) class II-III and received conventional pharmacologic therapy for CHF; this was not changed during the study period. The study design consisted of two treatment periods (CP or placebo and placebo or CP, respectively) of 4 days each, separated by a 2-day washout interval. The intravenous infusion consisted of 6 g CP or placebo (acute treatment) or 6 g CP or placebo daily for 4 days (short-term treatment) diluted in 50 ml of NaCl 0.9%; infusion duration was about 10 min. Mono-bidimensional echocardiographic examination (Hewlett Packard Sonos 1000, with a 2.5 MHz transducer) was performed at baseline, after acute infusion, and 12 h after the end of short-term treatment. Data were analyzed by ANOVA and Student's t-test for paired data; the results obtained after acute and short-term therapy were compared with the baseline values.

RESULTS

After placebo therapy, no significant change was observed. The results after treatment with CP showed a significant reduction of end-systolic diameter [baseline: 4.5 +/- 0.6; acute: 4.2 +/- 0.5, (p < 0.001); short-term 4.3 +/- 0.6 cm, (p < 0.05)] and systemic vascular resistance (baseline: 1064.9 +/- 483.7; acute: 947.5 +/- 390.2 (p < 0.05); short-term: 950.7 +/- 394.3 dyne-s-cm-5 (p < 0.05); moreover, a significant increase of percent ejection fraction [baseline: 48 +/- 12%; acute 53 +/- 12% (p < 0.01); short-term 52 +/- 11% (p < 0.01)], and of percent fractional shortening [baseline: 25 +/- 7; acute 28 +/- 8 (p < 0.05); short-term 28 +/- 7% (p < 0.05)] was observed.

CONCLUSION

CP was shown to improve cardiac function, even in the presence of a conventional CHF pharmacologic therapy.

St. Thomas' Hospital cardioplegia: enhanced protection with exogenous creatine phosphate

BACKGROUND

Experimentally, creatine phosphate (CP) improves postischemic recovery of function and reduces postischemic arrhythmias.

METHODS

We studied 50 patients undergoing valve replacement. They were randomized into either a control group, who received St. Thomas' Hospital cardioplegic solution No. 1, or a CP-treated group, receiving the same cardioplegic solution plus CP (10 mmol/L). There were no preoperative clinical differences between groups. Assessment was by electrocardiographic analysis, inotropic drug requirement, quantitative birefringence, myocardial high-energy phosphate content, function, and semiquantitative ultrastructural assessment.

RESULTS

Direct-current shocks were reduced in the CP-treated group (0.88 +/- 0.15) compared with the control group (1.40 +/- 0.14; p < 0.02), as was the total number of joules (22.0 +/- 3.5 versus 34.4 +/- 3.7, respectively; p <0.02). The incidence of spontaneous sinus rhythm was higher in the CP-treated group (40% versus 8%; p < 0.05) and the incidence of postoperative arrhythmias, lower (8% versus 32%; p < 0.05). Prolonged inotropic administration (12 hours or longer) occurred in fewer patients in the CP-treated group (4% versus 28%; p < 0.05). Response to inotropic support (in the subset of patients requiring this treatment) was significantly greater in the CP-treated group than in the control group. There were no differences in recovery of function, birefringence changes, myocardial high-energy phosphate content, or ultrastructure between groups.

CONCLUSIONS

St. Thomas' Hospital cardioplegic solution No. 1 plus CP enhanced myocardial protection and conferred a direct benefit to the patient by reducing postoperative arrhythmias and need of prolonged inotropic support.

Participation of calcium ions in the molecular mechanism of cardioprotective action of exogenous phosphocreatine

The purpose of this study was to find out whether Ca2+ is necessary for the protective effect of phosphocreatine (PCr) on ischemic myocardium. Isolated Langendorff-perfused rat hearts were used in the study. When ischemic arrest was induced in Ca(2+)-free buffer, PCr did not exert a protective effect on ischemic myocardium. PCr improved postischemic contractile recovery of hearts subjected to ischemia in perfusion media containing 0.5 and 1.2 mmol/l Ca2+. Phosphoarginine, a structural analogue of PCr which possesses Ca(2+)-binding property similar to that of PCr did not exert any protective effect on ischemic myocardium. The effects of PCr and Ca2+ on lipid order of sarcolemmal vesicles from canine heart were studied by using ESR spectroscopy. PCr made membrane phospholipids more tightly packed at mildly acidic and neutral pH, but did not at pH 8.5. Although Ca2+ itself did not influence the membrane structure at pH 5.5, it potentiated the effect of PCr on sarcolemmal phospholipids. Thus, the protective effect of PCr on ischemic myocardium is not attributed to its Ca2+ binding properly, but Ca2+ is a necessary component of the mechanism of protective effect of PCr on ischemic myocardium.

Electrophysiologic effects of exogenous phosphocreatine in cardiac tissue: potential antiarrhythmic actions

The cellular electrophysiologic effects of exogenous phosphocreatine (PCr) were analyzed to ascertain its purported antiarrhythmic properties during myocardial ischemia and reperfusion. Transmembrane potentials were recorded from isolated guinea pig papillary muscles and Purkinje fibers studied in vitro. Under control, normoxic conditions, 10 mmol/L PCr significantly increased the action potential duration (measured at 90% of repolarization) in ventricular muscle by 14.6 +/- 3.3 msec and the effective refractory period by 11.5 +/- 3.8 msec (both p less than 0.01). Under ischemic-like conditions (hypoxia, lactic acidosis, elevated [K+]o, zero substrate) PCr had no effect. Phosphocreatinine, a related compound that is not a direct substrate in the creatine kinase reaction, acted similarly to PCr suggesting that alterations induced by PCr did not involve a change in the energy state of cells. However, PCr reduced free [Ca2+]o by nearly 20%, and its electrical effects under normoxic conditions could be largely reversed by a concomitant 20% increase in [Ca2+]o. In Purkinje fibers superfused with low [K+]o-Tyrode's solution to elicit conditions of Ca2+ overload, delayed afterdepolarizations and triggered responses were reversibly inhibited by PCr. These data suggest that the antiarrhythmic effects of PCr in situ may involve prolongation of the effective refractory period in nonischemic tissue or attenuation of membrane changes elicited by Ca2+ overload in ischemic cells. The mechanism by which PCr produces these effects may be related in part to changes in extracellular Ca2+ composition.

Some mechanisms of nonspecific antiarrhythmic action of phosphocreatine in acute myocardial ischemia

Using isotope-labeled microspheres (diameter 15 microns) it was shown that phosphocreatine at a dose of 300 mg/kg does not affect the myocardial blood flow in the ischemic zone during acute occlusion (5 min) of the left anterior descending coronary artery (LAD) in dogs. Intravenous administration of NaCl hypertonic solution which contained the same amount of Na+ as 300 mg/kg of phosphocreatinine disodium salt prevented the development of ventricular fibrillation during acute LAD occlusion in dogs. Under these conditions excitation conduction velocity significantly increased. Experiments in isolated intraventricular rabbit septum have showed that the addition of phosphocreatine or phosphocreatinine to the perfusion medium at a concentration of 10 mmole/liter increased excitation conduction velocity in ischemic myocardium. However, when changes in perfusate Na+ and Ca2+ concentration produced by addition of phosphocreatine or phosphocreatinine were compensated, these compounds do not affect excitation conduction velocity. On the other hand, the alterations similar to those produced by the addition of phosphocreatine or phosphocreatinine led to the same increase of excitation conduction velocity. The results obtained indicate an important role of the changes of blood plasma ionic composition on intravenous administration of phosphocreatine in electrophysiological and antiarrhythmic effects of this substance during acute myocardial ischemia.

Reduction of ventricular arrhythmias by phosphocreatine (Neoton) in patients with acute myocardial infarction

On the basis of the positive results of recent experimental research, a clinical trial of phosphocreatine (Neoton) was carried out in 60 randomized patients with acute myocardial infarction (30 patients in the Neoton group and 30 patients in the control group). Neoton was given intravenously not later than 6 hours after the onset of symptoms, in a dose of 2 gm as a bolus injection, followed by a 2-hour infusion at the rate of 4 gm/hr. Holter monitoring for 24 hours showed a significant decrease in the frequency of ventricular premature beats: in the Neoton-treated group the total number of ventricular premature beats for 24 hours was 690 +/- 179 vs 2468 +/- 737 in the control group (p less than 0.02). During this period of time the number of ventricular tachycardia paroxysms was 6 +/- 2 in the treated group and 97 +/- 35 in the control group (p less than 0.01). No side effects or complications were found after administration of phosphocreatine. It is concluded that phosphocreatine may be a potentially important antiarrhythmic drug for treatment of patients with acute myocardial infarction.