Coenzyme Q10: the prophylactic effect on low cardiac output following cardiac valve replacement

Regulation of coenzyme Q biosynthesis pathway in eukaryotes

Coenzyme Q (CoQ, ubiquinone/ubiquinol) is a ubiquitous and unique molecule that drives electrons in mitochondrial respiratory chain and an obligatory step for multiple metabolic pathways in aerobic metabolism. Alteration of CoQ biosynthesis or its redox stage are causing mitochondrial dysfunctions as hallmark of heterogeneous disorders as mitochondrial/metabolic, cardiovascular, and age-associated diseases. Regulation of CoQ biosynthesis pathway is demonstrated to affect all steps of proteins production of this pathway, posttranslational modifications and protein-protein-lipid interactions inside mitochondria. There is a bi-directional relationship between CoQ and the epigenome in which not only the CoQ status determines the epigenetic regulation of many genes, but CoQ biosynthesis is also a target for epigenetic regulation, which adds another layer of complexity to the many pathways by which CoQ levels are regulated by environmental and developmental signals to fulfill its functions in eukaryotic aerobic metabolism.

Chronic hypoxia–induced Cirbp hypermethylation attenuates hypothermic cardioprotection via down-regulation of ubiquinone biosynthesis

Therapeutic hypothermia is commonly used during cardiopulmonary bypass (CPB) to protect the heart against myocardial injury in cardiac surgery. Patients who suffer from chronic hypoxia (CH), such as those with certain heart or lung conditions, are at high risk of severe myocardial injury after cardiac surgery, but the underlying mechanisms are unknown. This study tested whether CH attenuates hypothermic cardioprotection during CPB. Using a rat model of CPB, we found that hypothermic cardioprotection was impaired in CH rats but was preserved in normoxic rats. Cardiac proteomes showed that cold-inducible RNA binding protein (CIRBP) was significantly (P = 0.03) decreased in CH rats during CPB. Methylation analysis of neonatal rat cardiomyocytes under CH and myocardium specimens from patients with CH showed that CH induced hypermethylation of the Cirbp promoter region, resulting in its depression and failure to respond to cold stress. Cirbp-knockout rats showed attenuated hypothermic cardioprotection, whereas Cirbp-transgenic rats showed an enhanced response. Proteomics analysis revealed that the cardiac ubiquinone biosynthesis pathway was down-regulated during CPB in Cirbp-knockout rats, resulting in a significantly (P = 0.01) decreased concentration of ubiquinone (CoQ10). Consequently, cardiac oxidative stress was aggravated and adenosine 5′-triphosphate production was impaired, leading to increased myocardial injury during CPB. CoQ10-supplemented cardioplegic solution improved cardioprotection in rats exposed to CH, but its effect was limited in normoxic rats. Our study suggests that an individualized cardioprotection strategy should be used to fully compensate for the consequences of epigenetic modification of Cirbp in patients with CH who require therapeutic hypothermia.

Coenzyme Q10 in Cardiovascular and Metabolic Diseases: Current State of the Problem

The burden of cardiovascular and metabolic diseases is increasing with every year. Although the management of these conditions has improved greatly over the years, it is still far from perfect. With all of this in mind, there is a need for new methods of prophylaxis and treatment. Coenzyme Q10 (CoQ10) is an essential compound of the human body. There is growing evidence that CoQ10 is tightly linked to cardiometabolic disorders. Its supplementation can be useful in a variety of chronic and acute disorders. This review analyses the role of CoQ10 in hypertension, ischemic heart disease, myocardial infarction, heart failure, viral myocarditis, cardiomyopathies, cardiac toxicity, dyslipidemia, obesity, type 2 diabetes mellitus, metabolic syndrome, cardiac procedures and resuscitation.

Ubiquinol (Reduced Coenzyme Q10) and Cellular Oxygen Consumption in Patients Undergoing Coronary Artery Bypass Grafting

Ubiquinol is a fundamental component of cellular metabolism. Low ubiquinol levels have been associated with mortality. This was a substudy of a randomized trial in patients undergoing coronary artery bypass grafting. We drew blood before and after surgery. Ubiquinol or placebo was added to peripheral blood mononuclear cells for oxygen consumption (OCR) measurements. In vivo ubiquinol levels were lower postsurgery compared to presurgery (0.16 μmol/L [quartiles: 0.02-0.39], P = .01), although the difference disappeared when adjusting for hemoglobin levels (P = .30). There was no difference in presurgical basal (1.0 mL/min/mg [95% confidence interval [CI]: -0.9 to 2.2], P = .08) and maximal (0.5 mL/min/mg [95% CI: -4.3 to 7.3], P = .56) OCR in cells receiving ubiquinol or placebo. There was a difference in postsurgical basal (1.1 mL/min/mg [95% CI: 0.9-1.6], P < .001) and maximal (4.2 mL/min/mg [95% CI: 0.3-7.0], P = .01) OCR between the groups. We found no association between ubiquinol and OCR levels (all P > .05).

Coenzyme Q10 in the treatment of heart failure: A systematic review of systematic reviews

Introduction

This article is an attempt to provide an overview of systematic reviews to determine the efficacy of CQ10 supplementation in the treatment of patients with cardiovascular diseases (CVD).

Method and material

All reviews were identified through a systematic search of the following databases: Cochrane, DARE, Ovid, EMBASE, ISI Web of Knowledge, and PubMed. Check references studies and the quality of the studies was assessed by means of AMSTTAR. No meta-analyses were performed due to the heterogeneity of studies.

Result

Extracted data for Seven systematic reviews for primary outcomes, net changes in cardiac output, cardiac index, New York Heart Association functional classification, improved survival, based on existing evidence, there is a case for use of CoQ10 as an adjunctive therapy in congestive heart failure, especially in those patients unable to tolerate mainstream medical therapies.

Conclusion

Evidence suggests that the CoQ10 supplement may be a useful tool for managing patients with heart failure.

Current experience in testing mitochondrial nutrients in disorders featuring oxidative stress and mitochondrial dysfunction: rational design of chemoprevention trials

An extensive number of pathologies are associated with mitochondrial dysfunction (MDF) and oxidative stress (OS). Thus, mitochondrial cofactors termed "mitochondrial nutrients" (MN), such as α-lipoic acid (ALA), Coenzyme Q10 (CoQ10), and l-carnitine (CARN) (or its derivatives) have been tested in a number of clinical trials, and this review is focused on the use of MN-based clinical trials. The papers reporting on MN-based clinical trials were retrieved in MedLine up to July 2014, and evaluated for the following endpoints: (a) treated diseases; (b) dosages, number of enrolled patients and duration of treatment; (c) trial success for each MN or MN combinations as reported by authors. The reports satisfying the above endpoints included total numbers of trials and frequencies of randomized, controlled studies, i.e., 81 trials testing ALA, 107 reports testing CoQ10, and 74 reports testing CARN, while only 7 reports were retrieved testing double MN associations, while no report was found testing a triple MN combination. A total of 28 reports tested MN associations with "classical" antioxidants, such as antioxidant nutrients or drugs. Combinations of MN showed better outcomes than individual MN, suggesting forthcoming clinical studies. The criteria in study design and monitoring MN-based clinical trials are discussed.

The protective role of coenzyme Q10 in renal injury associated with extracorporeal shockwave lithotripsy: a randomised, placebo-controlled clinical trial

OBJECTIVE

To determine the efficacy of coenzyme Q10 (CoQ10) in preventing renal injury in patients with lithiasis undergoing extracorporeal shockwave lithotripsy (ESWL).

PATIENTS AND METHODS

Prospective, randomised, double-blind, placebo-controlled clinical trial of 100 patients with renal lithiasis who were treated with ESWL. The patients were distributed randomly into two groups receiving either placebo or CoQ10 (200 mg/day), a powerful antioxidant with vasoactive properties, orally administered during the week before ESWL and for 1 week after. Renal dysfunction markers, vasoactive hormones, oxidative stress, plasma levels of several interleukins and vascular resistance index (VRI) using Doppler ultrasound were evaluated the week before ESWL, 2 h before ESWL and at 2 h, 24 h and 7 days after ESWL.

RESULTS

There was a significant increase in glomerular filtration (P = 0.013), as well as a decrease in the albumin/creatinine ratio and the β2 -microglobulin level (P = 0.02) after 1 week of treatment in the CoQ10 group. These changes were maintained at the follow-up after ESWL. The administration of CoQ10 was associated with improvement in vasoactive hormone parameters, VRI and interleukin levels. These improvements were maintained until the end of the follow-up period. However, the administration of CoQ10 was not associated with significant changes in the oxidative stress parameters.

CONCLUSION

Our results indicate that CoQ10 administration improves renal function and vasoactive and inflammation parameter values, allowing for preconditioning before the tissue insult caused by ESWL.

Protective effect of coenzyme Q10-loaded liposomes on the myocardium in rabbits with an acute experimental myocardial infarction

PURPOSE

We assessed whether the infusion of Coenzyme Q10-loaded liposomes (CoQ10-L) in rabbits with an experimental myocardial infarction can result in increased intracellular delivery of CoQ10 and thus limit the fraction of the irreversibly damaged myocardium.

METHODS

CoQ10-L, empty liposomes (EL), or Krebs-Henseleit (KH) buffer were administered by intracoronary infusion, followed by 30 min of occlusion and 3 h of reperfusion. Unisperse Blue dye was used to demarcate the net size of the occlusion-induced ischemic zone ("area at risk") while nitroblue tetrazolium staining was used to detect the final fraction of the irreversibly damaged myocardium within the total area at risk.

RESULTS

The total size of the area at risk in all experimental animals was approx. 20% wt. of the left ventricle (LV). The final irreversible damage in CoQ10-L-treated animals was only ca. 30% of the total area at risk as compared with ca. 60% in the group treated with EL (p < 0.006) and ca. 70% in the KH buffer-treated group (p < 0.001).

CONCLUSIONS

CoQ10-L effectively protected the ischemic heart muscle by enhancing the intracellular delivery of CoQ10 in hypoxic cardiocytes in rabbits with an experimental myocardial infarction as evidenced by a significantly decreased fraction of the irreversibly damaged heart within the total area at risk. CoQ10-L may provide an effective exogenous source of the CoQ10 in vivo to protect ischemic cells.

Coenzyme Q10 in cardiovascular disease

In this review we summarise the current state of knowledge of the therapeutic efficacy and mechanisms of action of CoQ(10) in cardiovascular disease. Our conclusions are: 1. There is promising evidence of a beneficial effect of CoQ(10) when given alone or in addition to standard therapies in hypertension and in heart failure, but less extensive evidence in ischemic heart disease. 2. Large scale multi-centre prospective randomised trials are indicated in all these areas but there are difficulties in funding such trials. 3. Presently, due to the notable absence of clinically significant side effects and likely therapeutic benefit, CoQ(10) can be considered a safe adjunct to standard therapies in cardiovascular disease.

Coenzyme Q10 therapy before cardiac surgery improves mitochondrial function and in vitro contractility of myocardial tissue

OBJECTIVES

Previous clinical trials suggest that coenzyme Q(10) might afford myocardial protection during cardiac surgery. We sought to measure the effect of coenzyme Q(10) therapy on coenzyme Q(10) levels in serum, atrial trabeculae, and mitochondria; to assess the effect of coenzyme Q(10) on mitochondrial function; to test the effect of coenzyme Q(10) in protecting cardiac myocardium against a standard hypoxia-reoxygentation stress in vitro; and to determine whether coenzyme Q(10) therapy improves recovery of the heart after cardiac surgery.

METHODS

Patients undergoing elective cardiac surgery were randomized to receive oral coenzyme Q(10) (300 mg/d) or placebo for 2 weeks preoperatively. Pectinate trabeculae from right atrial appendages were excised, and mitochondria were isolated and studied. Trabeculae were subjected to 30 minutes of hypoxia, and contractile recovery was measured. Postoperative cardiac function and troponin I release were assessed.

RESULTS

Patients receiving coenzyme Q(10) (n = 62) had increased coenzyme Q(10) levels in serum (P = .001), atrial trabeculae (P = .0001), and isolated mitochondria (P = .0002) compared with levels seen in patients receiving placebo (n = 59). Mitochondrial respiration (adenosine diphosphate/oxygen ratio) was more efficient (P = .012), and mitochondrial malondialdehyde content was lower (P = .002) with coenzyme Q(10) than with placebo. After 30 minutes of hypoxia in vitro, pectinate trabeculae isolated from patients receiving coenzyme Q(10) exhibited a greater recovery of developed force compared with those in patients receiving placebo (46.3% +/- 4.3% vs 64.0% +/- 2.9%, P = .001). There was no between-treatment difference in preoperative or postoperative hemodynamics or in release of troponin I.

CONCLUSIONS

Preoperative oral coenzyme Q(10) therapy in patients undergoing cardiac surgery increases myocardial and cardiac mitochondrial coenzyme Q(10) levels, improves mitochondrial efficiency, and increases myocardial tolerance to in vitro hypoxia-reoxygenation stress.

The placebo effect and randomized trials: analysis of alternative medicine

Randomized controlled trials are generally regarded as the gold standard of study designs to determine causality. The inclusion of a placebo group in these trials, when appropriate, is critical to access the efficacy of a drug or supplement. The placebo response itself has received some attention in the medical literature over the past fifty years. The recent increasing utilization of dietary supplements and herbal medications by patients makes it imperative to reevaluate the placebo response in conventional and alternative medicine. This article will review some of the negative and positive results from randomized trials utilizing dietary supplements (androstenedione, beta-carotene, CoQ10, garlic, soy, vitamin C and E...) for a number of non-urologic and urologic conditions, including cancer.

Dietary supplements

The amount of published information on dietary supplements mushroomed in the 1990s. In fewer than 5 years, publications increased at least 100-fold in the medical literature alone. Dietary supplements are an uncharted territory that warrants complete and accurate exploration. One should not be surprised that disease and illness may respond to dietary supplements. Nutrition is the foundation to good health, and dietary supplements may prove to be some of the most powerful medicines ever discovered. An especially exciting discovery is that dietary supplements may enhance the effects of specific drugs. This discovery may lead to more effective and safer protocols for the treatment of cancer, heart and lung disease, and a host of chronic medical conditions. Information about dietary supplements is becoming more common in the popular medical literature and is creating increased curiosity and an increased awareness. The explosion of the dietary supplement market is compelling physicians to become aware of dietary supplements. Whether or not they are used in clinical practice is a decision for the individual physician. Given the increasing number of patients who are using dietary supplements, however, it is imperative that physicians have a good understanding of this topic. Considering the increasing complexity and magnitude of this topic, physician specialization may be essential. There are many good reference books, review articles, and internet sites on specific supplements that probably should be part of every physician's reference library. The accompanying box provides a brief list of such sources.

The effect of coenzyme Q10 in patients with congestive heart failure

BACKGROUND

Coenzyme Q10 is commonly used to treat congestive heart failure on the basis of data from several unblinded, subjective studies. Few randomized, blinded, controlled studies have evaluated objective measures of cardiac performance.

OBJECTIVE

To determine the effect of coenzyme Q10 on peak oxygen consumption, exercise duration, and ejection fraction.

DESIGN

Randomized, double-blind, controlled trial.

SETTING

University and Veterans Affairs hospitals.

PATIENTS

55 patients who had congestive heart failure with New York Heart Association class III and IV symptoms, ejection fraction less than 40%, and peak oxygen consumption less than 17.0 mL/kg per minute (or <50% of predicted) during standard therapy were randomly assigned. Forty-six patients completed the study.

INTERVENTION

Coenzyme Q10, 200 mg/d, or placebo.

MEASUREMENTS

Left ventricular ejection fraction (measured by radionuclide ventriculography) and peak oxygen consumption and exercise duration (measured by a graded exercise evaluation using the Naughton protocol) with continuous metabolic monitoring.

RESULTS

Although the mean (+/-SD) serum concentration of coenzyme Q10 increased from 0.95+/-0.62 microg/mL to 2.2+/-1.2 microg/mL in patients who received active treatment, ejection fraction, peak oxygen consumption, and exercise duration remained unchanged in both the coenzyme Q10 and placebo groups.

CONCLUSION

Coenzyme Q10 does not affect ejection fraction, peak oxygen consumption, or exercise duration in patients with congestive heart failure receiving standard medical therapy.

Overview of the use of CoQ10 in cardiovascular disease

The clinical experience in cardiology with CoQ10 includes studies on congestive heart failure, ischemic heart disease, hypertensive heart disease, diastolic dysfunction of the left ventricle, and reperfusion injury as it relates to coronary artery bypass graft surgery. The CoQ10-lowering effect of HMG-CoA reductase inhibitors and the potential adverse consequences are of growing concern. Supplemental CoQ10 alters the natural history of cardiovascular illnesses and has the potential for prevention of cardiovascular disease through the inhibition of LDL cholesterol oxidation and by the maintenance of optimal cellular and mitochondrial function throughout the ravages of time and internal and external stresses. The attainment of higher blood levels of CoQ10 (> 3.5 micrograms/ml) with the use of higher doses of CoQ10 appears to enhance both the magnitude and rate of clinical improvement. In this communication, 34 controlled trials and several open-label and long-term studies on the clinical effects of CoQ10 in cardiovascular diseases are reviewed.

Bioenergetic effect of liposomal coenzyme Q10 on myocardial ischemia reperfusion injury

The antioxidant and bioenergetic effects of CoQ10 are well known but its clinical utility is limited by the requirement for enteral administration. A newly developed liposomal CoQ10 (CoQ) is water soluble and capable of intravenous administration. The purpose of this study is to determine the mechanism by which acute administration CoQ protects myocardium from reperfusion (Rp) injury. Rats were pretreated with CoQ 10 mg/kg i.v. 30 min prior to the experiment. Control rats were pretreated with liposome only. Hearts were excised and subjected to equilibration, 25 min of normothermic ischemia and 40 min of Rp on a Langendorff apparatus. At end Rp, CoQ hearts recovered 74 +/- 5% of their DP vs. 50 +/- 9% in control (p < 0.05). Aerobic efficiency was maintained (0.66 +/- 0.02 vs. control, 0.5 +/- 0.04, p < 0.003) and CoQ hearts lost less CK activity vs. control (p < 0.02). PCr and ATP were higher than control (p < 0.05, 0.02, respectively). Results show that i.v. CoQ improves recovery of function, aerobic efficiency, CK activity, and recovery of PCr and ATP after Rp. This suggests that acute administration of liposomal CoQ improves myocardial tolerance to I/R via its role as an antioxidant as well as improving oxygen utilization and high energy phosphate production.

Acute administration of liposomal coenzyme Q10 increases myocardial tissue levels and improves tolerance to ischemia reperfusion injury

The antioxidant and bioenergetic effects of CoQ10 (CoQ) suggest it might be ideal therapy for acute myocardial ischemia. Its utility is limited by the requirement for enteral administration. This study related the administration of a new liposomal suspension of CoQ given intravenously to (1) serum and myocardial [CoQ] and (2) recovery of function, myocardial efficiency, and oxidant injury after cardiac ischemia and reperfusion (I/R). Rats (n = 8/group) were given liposomal CoQ 10 mg/kg iv or placebo (Control), 15 min (C-15), 30 min (C-30), and 60 min (C-60) before (1) measurement of serum and myocardial CoQ or (2) Langendorff perfusion of hearts subjected to 15 min equilibration, 25 min ischemia (37 degrees C), and 40 min reperfusion (RP). Developed pressure (DP) was measured via an intraventricular balloon and coronary flow was measured by a digital flow meter. Myocardial efficiency was defined as DP/MVO2 where MVO2 = microl O2 consumed/min/gram LV. At end RP hearts were assayed for CK, an oxidant sensitive enzyme. Maximum preischemic CoQ levels in serum and myocardium occurred 15 and 30 min after administration, respectively. At end reperfusion, C-30 hearts improved the most, recovering 75 +/- 4% of their preischemic DP while Control recovered only 52 +/- 6% (P < 0.03) as well as maintaining better myocardial efficiency (0.69 +/- 0.02 vs Control, 0.43 +/- 0.05) (P < 0.001). C-15, C-30, and C-60 groups all lost less CK activity after RP vs Control (P < 0.04).

CONCLUSION

(1) Serum and myocardial levels of CoQ can be raised acutely by iv liposomal CoQ. (2) Myocardial CoQ levels correlate best with I/R protection. (3) Acute iv CoQ improves function and efficiency and decreases oxidant injury after I/R. Intravenous CoQ may be effective clinically for acute cardiac ischemic syndromes.

Reperfusion injury: a review of the pathophysiology, clinical manifestations and therapeutic options

Lack of blood supply or ischaemia underlies many of the most important cardiovascular and cerebrovascular diseases faced by clinicians in their daily practice. Many of these ischaemic episodes can be reversed at an early stage by surgical or pharmacological means with the ultimate aim of preventing infarction and cell necrosis in the ischaemic tissues. However, reperfusion of ischaemic areas, in particular the readmission of oxygen, may contribute to further tissue damage (reperfusion injury). For example, the use of thrombolytic therapy in acute myocardial infarction and other revascularisation procedures, such as percutaneous transluminal angioplasty and coronary artery bypass surgery, may be associated with reperfusion of ischaemic myocardium. Such ischaemia and reperfusion may result in injury to one of more of the biochemical, cellular and microvascular components of the heart. Our understanding of the significance of reperfusion injury is however restricted by the profuse literature in animal models and limited literature in the clinical situation. This article reviews the pathophysiology, clinical manifestations of reperfusion injury to the heart and discusses the possible therapeutic approaches to avoiding any adverse effects.

Effects of short-term supplementation with coenzyme Q10 on myocardial protection during cardiac operations

BACKGROUND

Coenzyme Q10 (CoQ10) is a naturally occurring vitamin-like substance that may have a beneficial role in ischemia-reperfusion injury. Coenzyme Q10 administered either as an additive to cardioplegia or as long-term preoperative oral supplementation has been reported to ameliorate myocardial injury after cardiac operations.

METHODS

To determine whether short-term supplementation with large doses of CoQ10 (600 mg in divided doses 12 hours before operation) was effective in myocardial protection, 20 patients with well-preserved left ventricular function (ejection fraction greater than 0.50) undergoing elective coronary revascularization were enrolled in a prospective, double-blind, placebo-controlled randomized trial. Serial concentrations of CoQ10, myoglobin, creatine kinase MD fraction, and cardiac troponin T were measured preoperatively and 1, 6, 24, 72, and 120 hours postoperatively. Efficacy of myocardial protection was also assessed by clinical outcome and serial changes in electrocardiographic indices.

RESULTS

The patient groups were similar with respect to preoperative and intraoperative characteristics. There was no significant difference in the preoperative plasma levels of CoQ10. These levels fell significantly in both groups after operation, although the magnitude of the decrease was less in the CoQ10-supplemented group (43% versus 60%). In both groups, there were significant postoperative increases in myoglobin, creatine kinase MB fraction, and cardiac troponin T. The magnitude of increases in cardiac troponin T was greater in the CoQ10-supplemented group, reaching marginal overall statistical significance (p = 0.06).

CONCLUSIONS

Short-term supplementation with large doses of CoQ10 does not lead to improved myocardial protection in patients undergoing coronary revascularization with well-preserved ventricular function and relatively short ischemic times.

Protection by coenzyme Q10 from myocardial reperfusion injury during coronary artery bypass grafting

To evaluate the effect of coenzyme Q10 in reducing postoperative cardiac complications after ischemia and reperfusion, we randomly divided 40 patients undergoing elective coronary artery bypass into two groups: patients in group 1 received coenzyme Q10 (150 mg/day) for 7 days before operation, and those in group 2 were the control group. Concentrations of thiobarbituric acid-reactive substances (malondialdehyde), conjugated dienes, and cardiac isoenzymes of creatine kinase were measured in samples from both arterial and coronary sinus sites. Serial sampling was performed 5 minutes after heparin administration, at 10 and 30 minutes during cardiopulmonary bypass, 15 and 30 minutes after aortic cross-clamp removal, and 5 minutes after protamine administration. The concentrations of malondialdehyde, conjugated dienes, and creatine kinase in group 1 were significantly lower than those in group 2. The decrease in plasma malondialdehyde concentrations correlated positively with the decrease in creatine kinase levels in the coronary sinus. The treatment group showed a significantly lower incidence of ventricular arrhythmias during the recovery period than did the control group (p < 0.05). Although the percentage of patients requiring inotropic agents was not significantly different between the two groups, the mean dosage of dopamine required to maintain stable hemodynamics was significantly lower in patients of group 1 than in those of group 2 (p < 0.01). Our findings suggest that pretreatment with coenzyme Q10 may play a protective role during routine bypass grafting by attenuating the degree of peroxidative damage.

Clinical experience of coenzyme Q10 to enhance intraoperative myocardial protection in coronary artery revascularization

Seventy-eight patients undergoing coronary artery bypass grafting (CABG) were compared retrospectively to evaluate whether pretreatment with coenzyme Q10 (CoQ) is effective in preventing left ventricular depression in early reperfusion following CABG. CoQ (5 mg/kg, intravenously) was given to 60 patients, 2 hours prior to the onset of cardiopulmonary bypass (CPB). CABG was performed using saphenous vein under CPB associated with cold cardioplegia in the standard fashion. Heart rate, mean arterial pressure, and cardiac index showed no significant difference between the CoQ and control groups. However, left ventricular stroke work index was significantly elevated at 6 and 10 hours of reperfusion following CABG in the CoQ-treated group compared with the controls. Serum MB-CK was lower at 0 and 6 hours of reperfusion in the CoQ group compared with the controls. These results suggest that pretreatment with intravenous CoQ is effective in preventing left ventricular depression in early reperfusion and in minimizing myocardial cellular injury during CABG followed by reperfusion.

Co-enzyme Q10: a new drug for cardiovascular disease

Co-enzyme Q10 (ubiquinone) is a naturally occurring substance which has properties potentially beneficial for preventing cellular damage during myocardial ischemia and reperfusion. It plays a role in oxidative phosphorylation and has membrane stabilizing activity. The substance has been used in oral form to treat various cardiovascular disorders including angina pectoris, hypertension, and congestive heart failure. Its clinical importance is now being established in clinical trails worldwide.

Ubiquinol-10 is an effective lipid-soluble antioxidant at physiological concentrations

It is well known that ubiquinone-10 (coenzyme Q10, ubiquinone 50) acts as an electron carrier of the respiratory chain in mitochondria. In this paper we show that ubiquinol-10, the reduced form of ubiquinone-10, also efficiently scavenges free radicals generated chemically within liposomal membranes. Ubiquinol-10 is about as effective in preventing peroxidative damage to lipids as alpha-tocopherol, which is considered the best lipid-soluble antioxidant in humans. The number of radicals scavenged by each molecule of ubiquinol-10 is 1.1 under our experimental conditions. In contrast to alpha-tocopherol, ubiquinol-10 is not recycled by ascorbate. However, it is known that ubiquinol-10 can be recycled by electron transport carriers present in various biomembranes and possibly by some enzymes. We also show that ubiquinol-10 spares alpha-tocopherol when both antioxidants are present in the same liposomal membranes and that ubiquinol-10, like alpha-tocopherol, does not interact with reduced glutathione. Our data together with previous work on the antioxidant function of ubiquinol reported in the literature strongly suggest that ubiquinol-10 is an important physiological lipid-soluble antioxidant.

Myocardial infarction in rats: effects of metabolic and pharmacologic interventions

Myocardial infarction was induced in rats by ligation of the descending branch of the left coronary artery. The time course of changes in heart function was recorded within the first nine days. There was a progressive decline in LVSP, in LV dP/dtmax and in the pressure-rate-product. LVEDP was elevated. Cardiac output and stroke volume index were depressed after two days. The ATP content in the nonischemic region was lower than control, but recovered spontaneously toward the normal value within the first four days. Three metabolic and pharmacologic interventions known to affect cardiac adenine nucleotide metabolism were applied. Continuous i.v. administration of ribose which stimulates further adenine nucleotide biosynthesis attenuated the fall and promoted the restoration of ATP in the nonischemic myocardium within four days after coronary artery ligation. The elevation of LVEDP was attenuated with ribose after two and four days. The calcium antagonist gallopamil administered as i.v. infusion for two days led to a further reduction of all parameters of left heart function, but did not influence the increase in adenine nucleotide and protein synthesis that occurred in the nonischemic heart. Coenzyme Q10 had only slight effects on LVSP, LVEDP, and LV dP/dtmax, but attenuated significantly the fall in cardiac output and stroke volume index after two days following coronary artery ligation. Thus, all interventions affected differently the infarct-induced changes in heart and circulatory function. An improvement was observed with ribose and with coenzyme Q10.

Coenzyme Q10: a new drug for myocardial ischemia?

A biochemical rationale for using CoQ in treating certain cardiovascular diseases has been established. CoQ subserves an endogenous function as an essential cofactor in several metabolic pathways, particularly oxidative respiration. As an exogenous source in supraphysiologic doses, CoQ may have pharmacologic effects that are beneficial to tissues rendered ischemic and then reperfused. Its mechanism of action appears to be that of a free radical scavenger and/or direct membrane stabilizer. Initial clinical studies performed abroad and in the United States indicate that CoQ may be effective in treating certain patients with ischemic heart disease, congestive heart failure, toxin-induced cardiotoxicity, and possibly hypertension. The most intriguing property of CoQ is its potential to protect and preserve ischemic myocardium during surgery. Currently, CoQ is still considered an experimental agent and only further studies will determine whether it will be useful therapy for human cardiovascular disease states.

Improved efficacy of intra-aortic balloon pumping by pharmacological myocardial protection for postoperative pump failure after coronary revascularization

Fifty patients took part in a randomized and prospective study to define the effect of pharmacological myocardial protection when using IABP in patients with postoperative pump failure, following coronary revascularization under cardiopulmonary bypass employing moderate hypothermia and cardioplegia. Pharmacological protection was given to 23 patients, administering coenzyme Q, 5 mg/kg, and aprotinin, 10,000 KIU/kg, intravenously, every 12 hours, following surgery. A single dose of each drug was also given intraoperatively. The postoperative haemodynamics, serum enzyme levels and success of weaning from IABP, were compared between the group of patients who received pharmacological protection (the treated group) and the control group which comprised 27 patients who were treated only with IABP. Among the surviving patients, no significant differences were seen in the hemodynamics or cardiac enzyme levels between the two groups. The rate of successful weaning from IABP however, was 95 per cent in the treated group as compared with only 74 per cent in the control group, p = 0.02. These results suggest that pharmacological myocardial protection, using coenzyme Q and aprotinin in both the intra- and post-operative periods, improves the efficacy of IABP in the treatment of post-operative pump failure following coronary revascularization.

Pathophysiology of superoxide radical as potential mediator of reperfusion injury in pig heart

The role of oxygen-derived free radicals in myocardial reperfusion injury was studied using the isolated in situ pig heart model. The free radical scavengers, superoxide dismutase (SOD) and catalase, protected the ischemic pig heart subjected to one hour of normothermic regional ischemia followed by one hour of global hypothermic arrest and one hour normothermic reperfusion. A significant increase in thiobarbituric acid reactive material and oxidized glutathione appeared in the perfusate demonstrating free radical-mediated lipid peroxidation during reperfusion, and this was prevented by the addition of SOD plus catalase. The values of three important antioxidative enzymes, SOD, catalase, and glutathione peroxidase, showed reduced activities after 2 hours of ischemia. These values did not change significantly after 60 minutes of reperfusion following the 2 hours ischemic insult. The concentrations of high-energy phosphate compounds including creatine phosphate (CP), adenosine triphosphate (ATP), and total adenine nucleotide were reduced significantly during ischemia and reperfusion in hearts which were not protected by SOD and catalase. The plasma creatine phosphokinase levels were lowered appreciably as a result of SOD and catalase treatment. It may be concluded from these experiments that oxygen-derived free radicals are present during reperfusion and SOD and catalase play a significant role in the protection of ischemic myocardium from reperfusion injury.

Effects of coenzyme Q10 added to a potassium cardioplegic solution for myocardial protection during ischemic cardiac arrest

To evaluate effects of coenzyme Q10 added to a potassium cardioplegic solution for myocardial protection, 17 mongrel dogs underwent 60 minutes of ischemic cardiac arrest under cardiopulmonary bypass. Cardiac arrest was induced by infusing the cardioplegic solution into the aortic root every 20 minutes. Experimental animals were divided into three groups according to the cardioplegic solution used. In Group 1, we used our clinical potassium cardioplegic solution (K+, 22.31 mEq/L); in Group 2, potassium cardioplegic solution with coenzyme Q10 added (coenzyme Q10, 30 mg/500 ml of solution); and in Group 3, cardioplegic solution with coenzyme Q10 solvent. Exogenous coenzyme Q10 in the cardioplegic solution provided significantly high myocardial stores of adenosine triphosphate and creatine phosphate and a low level of lactate during induced ischemia and reperfusion. Furthermore, percent recovery of the aortic flow in Group 2 was significantly higher than that in the other two groups. Ultrastructures of the ischemic myocardium in Group 2 were better preserved than those in Group 1. Addition of coenzyme Q10 to potassium cardioplegia resulted in improved myocardial oxygen utilization and accelerated recovery of myocardial energy metabolism after reestablishment of circulation.

Effects of pretreatment with coenzyme Q10 on myocardial preservation during aortic cross clamping

A protective effect of coenzyme Q10 on the ischemic and reperfused myocardium was investigated in the isolated working rat heart preparation. Rats were treated intraperitoneally with 30 mg/kg coenzyme Q10, daily for 7 days. The controls were given the same dose of the vehicle. After 25 min of equilibration the hearts were made totally ischemic at 35.5 degrees C for 30 min, arrested with high potassium cardioplegic solution immediately after aortic cross clamping. The recovery of cardiac power in the coenzyme Q10 pretreated group was significantly (P less than 0.05) better than that in vehicle pretreated group. Creatine phosphokinase (CPK) release during reperfusion was significantly (P less than 0.05) reduced by the pretreatment of coenzyme Q10. Tissue analysis for high energy phosphate compounds revealed no significant difference between the two groups. Tissue lactate content at 30 min of ischemia was significantly (P less than 0.001) lower in the coenzyme Q10 pretreated group. These results suggest that pretreatment with coenzyme Q10 is effective for reducing ischemic injury caused by aortic cross clamping.