Pyung Chun Oh

Does reversal of oxidative stress and inflammation provide vascular protection

Chronic inflammation is a pathogenic feature of atherosclerosis and cardiovascular disease mediated by substances including angiotensin II, proinflammatory cytokines, and free fatty acids. This promotes generation of reactive oxygen species in vascular endothelial cells and smooth muscle cells, which mediate injury through several mechanisms. Reciprocal relationships between endothelial dysfunction and insulin resistance as well as cross-talk between hyperlipidaemia and the renin-angiotensin-aldosterone system (RAAS) at multiple levels contribute importantly to a variety of risk factors. Therefore, combination therapy that simultaneously addresses multiple mechanisms for the pathogenesis of atherosclerosis is an attractive emerging concept for slowing progression of atherosclerosis. Combined therapy with statins, peroxisome proliferator-activated receptors, and RAAS blockade demonstrates additive beneficial effects on endothelial dysfunction and insulin resistance when compared with monotherapies in patients with cardiovascular risk factors due to both distinct and interrelated mechanisms. These additive beneficial effects of combined therapies are consistent with laboratory and recent clinical studies. Thus, combination therapy may be an important paradigm for treating and slowing progression of atherosclerosis, coronary heart disease, and co-morbid metabolic disorders characterized by endothelial dysfunction and insulin resistance.

Combination therapy for treatment or prevention of atherosclerosis: Focus on the lipid-RAAS interaction

Large clinical trials demonstrate that control of blood pressure or hyperlipidemia reduces risk for cardiovascular events by approximately 30%. Factors that may further reduce remaining risk are not definitively established. One potential target is atherosclerosis, a crucial feature in the pathogenesis of cardiovascular diseases whose development is determined by multiple mechanism including complex interactions between endothelial dysfunction and insulin resistance. Reciprocal relationships between endothelial dysfunction and insulin resistance as well as cross-talk between hyperlipidemia and the rennin-angiotensin-aldosterone system may contribute to development of atherosclerosis. Therefore, one appealing strategy for prevention or treatment of atherosclerosis may be to simultaneously address several risk factors with combination therapies that target multiple pathogenic mechanisms. Combination therapy with statins, peroxisome proliferators-activated receptor agonists, and rennin-angiotensin-aldosterone system blockers demonstrate additive beneficial effects on endothelial dysfunction and insulin resistance when compared with monotherapies in patients with cardiovascular risk factors. Additive beneficial effects of combined therapy are mediated by both distinct and interrelated mechanisms, consistent with both pre-clinical and clinical investigations. Thus, combination therapy may be an important concept in developing more effective strategies to treat and prevent atherosclerosis, coronary heart disease, and co-morbid metabolic disorders characterized by endothelial dysfunction and insulin resistance.

Omega-3 fatty acid therapy dose-dependently and significantly decreased triglycerides and improved flow-mediated dilation, however, did not significantly improve insulin sensitivity in patients with hypertriglyceridemia.

BACKGROUND Experimental studies demonstrate that higher intake of omega-3 fatty acids (n-3 FA) improves insulin sensitivity, however, we reported that n-3 FA 2g therapy, most commonly used dosage did not significantly improve insulin sensitivity despite reducing triglycerides by 21% in patients. Therefore, we investigated the effects of different dosages of n-3 FA in patients with hypertriglyceridemia. METHODS This was a randomized, single-blind, placebo-controlled, parallel study. Age, sex, and body mass index were matched among groups. All patients were recommended to maintain a low fat diet. Forty-four patients (about 18 had metabolic syndrome/type 2 diabetes mellitus) in each group were given placebo, n-3 FA 1 (O1), 2 (O2), or 4 g (O4), respectively daily for 2 months. RESULTS n-3 FA therapy dose-dependently and significantly decreased triglycerides and triglycerides/HDL cholesterol and improved flow-mediated dilation, compared with placebo (by ANOVA). However, each n-3 FA therapy did not significantly decrease high-sensitivity C-reactive protein and fibrinogen, compared with placebo. O1 significantly increased insulin levels and decreased insulin sensitivity (determined by QUICKI) and O2 significantly decreased plasma adiponectin levels relative to baseline measurements. Of note, when compared with placebo, each n-3 FA therapy did not significantly change insulin, glucose, adiponectin, glycated hemoglobin levels and insulin sensitivity (by ANOVA). We observed similar results in a subgroup of patients with the metabolic syndrome. CONCLUSIONS n-3 FA therapy dose-dependently and significantly decreased triglycerides and improved flow-mediated dilation. Nonetheless, n-3 FA therapy did not significantly improve acute-phase reactants and insulin sensitivity in patients with hypertriglyceridemia, regardless of dosages.

Vascular and metabolic effects of ezetimibe combined with simvastatin in patients with hypercholesterolemia

BACKGROUND Ezetimibe demonstrates decreasing visceral fat and improving insulin sensitivity (IS) in animals and humans. We first reported that simvastatin dose-dependently worsens insulin sensitivity. Whether ezetimibe may compensate untoward effects of simvastatin, depending on dosages of simvastatin has not been investigated in patients with hypercholesterolemia, compared with simvastatin alone. METHODS This was a randomized, single-blind, placebo-controlled, parallel study. Fifty-one in each group were given placebo, ezetimibe 10mg combined with simvastatin 10mg (Vyto10), ezetimibe 10mg combined with simvastatin 20mg (Vyto20), or simvastatin 20mg alone (Simva20) daily for 2months. RESULTS Placebo, Vyto10, Vyto20, and Simva20 improved flow-mediated dilation relative to baseline measurements. Placebo therapy did not significantly change insulin and IS and adiponectin levels and visceral fat area (VFA) and VFA/subcutaneous fat area (SFA) relative to baseline measurements. Vyto10 therapy significantly decreased CRP and insulin levels and increased adiponectin levels and IS, and reduced VFA, VFA/SFA, and blood pressure. Vyto20 therapy did not significantly change insulin levels and IS and adiponectin levels but significantly reduced CRP levels and VFA, VFA/SFA, and blood pressure. Simva20 therapy significantly decreased adiponectin levels and IS but did not significantly change VFA, VFA/SFA, and blood pressure. Of note, these different effects of each therapy were significant by ANOVA. CONCLUSIONS Vyto10, Vyto20, and Simva20 showed significant reduction of LDL cholesterol levels and improvement of flow-mediated dilation in patients with hypercholesterolemia. However, Vyto10, Vyto20, and Simva20 showed significantly differential metabolic effects, depending on dosages of simvastatin.

Combination Pravastatin and Valsartan Treatment Has Additive Beneficial Effects to Simultaneously Improve Both Metabolic and Cardiovascular Phenotypes Beyond That of Monotherapy With Either Drug in Patients With Primary Hypercholesterolemia

Statin and angiotensin II type 1 receptor blocker therapy improves endothelial dysfunction using distinct mechanisms. We evaluated simultaneous vascular and metabolic responses to pravastatin and valsartan therapy, alone or in combination, in hypercholesterolemic patients. Forty-eight hypercholesterolemic patients (23 had metabolic syndrome) were given pravastatin 40 mg and placebo, pravastatin 40 mg and valsartan 160 mg, or valsartan 160 mg and placebo daily during each 2-month treatment period in a randomized, single-blind, placebo-controlled, crossover trial with three treatment arms and two washout periods (each 2 months). Brachial artery flow-mediated dilation and C-reactive protein improved to a greater extent with combined therapy compared with either monotherapy. Importantly, we also observed simultaneous improvement in metabolic phenotypes, with all three treatments causing increased plasma adiponectin levels, reduced fasting insulin levels, and increased insulin sensitivity relative to baseline measurements. For the first time in a statin combination trial, pravastatin combined with valsartan therapy increased plasma adiponectin, lowered fasting insulin levels, and improved insulin sensitivity in an additive manner when compared with monotherapy alone. In contrast to other statins, hydrophilic pavastatin may be combined with other drugs to safely reach lipid target levels while simultaneously improving the metabolic and cardiovascular phenotype of patients at high risk.

Serum transaminase determined in the emergency room predicts outcomes in patients with acute ST-segment elevation myocardial infarction who undergo primary percutaneous coronary intervention.

BACKGROUND Elevated serum aspartate and alanine aminotransferase (AST and ALT) are often observed in patients with acute ST-segment elevation myocardial infarction (STEMI) and the condition is ascribed to liver hypoperfusion. We evaluated the prevalence and prognostic implication of hypoxic liver injury (HLI) in STEMI. METHODS Patients with STEMI and no preexisting liver disease who underwent primary percutaneous coronary intervention (PCI) were enrolled. A blood test was performed at the time of presentation and transthoracic echocardiography was performed after the index PCI. We reviewed medical records and contacted families of the patients by telephone to assess outcomes. RESULTS Of 456 patients (age 60 ± 13 years, 370 males), 31 patients (7%) died during follow-up (duration: 754 ± 540 days). Those patients were older (72 ± 10 vs. 59 ± 13 years), had higher AST (179 ± 224 vs. 64 ± 103 U/L), ALT (56 ± 79 vs. 35 ± 33 U/L), blood urea nitrogen (25 ± 15 vs. 17 ± 7 mg/dL), uric acid (6.9 ± 2.9 vs. 5.8 ± 1.6 mg/dL), creatine kinase-myocardial band isoenzyme (76 ± 104 vs. 41 ± 79 ng/mL), troponin I (19.9 ± 23.0 vs. 10.8 ± 19.1 ng/mL), and lower albumin (4.0 ± 0.5 vs. 4.2 ± 0.4 g/dL) at the time of presentation (p<0.05 for all). Particularly, AST independently predicted all-cause mortality (per 10 U/L increase, hazard ratio: 1.06, 95% confidence interval: 1.02-1.10, p=0.007), whereas cardiac markers did not. HLI (>2-fold elevation of AST or ALT upper normal limits) showed close correlation with reduced left ventricular ejection fraction (β=-0.12, p=0.03) and patients with the condition (n=100 [20%]) had poorer survival than the others (Log-Rank, p=0.005). CONCLUSION The presence of HLI predicts mortality in patients with STEMI who undergo successful primary PCIs.

How to balance cardiorenometabolic benefits and risks of statins

Statins, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, are important for preventing adverse cardiovascular events not only in patients with a high risk of vascular disease but also in those with a low risk, by reducing the levels of low-density lipoprotein cholesterol. Statin is associated with deteriorating glucose homeostasis and an increased risk of diabetes mellitus. Moreover, these off-target effects are dose-dependent; it has also been suggested that renal insult can be caused dose-dependently by statin treatment, in contrast to previous studies showing a renoprotective effect. The 2013 American College of Cardiology/American Heart Association guidelines recommend the use of high-intensity statin therapy, and extend its use to more people at risk of vascular diseases. However, a European committee has expressed concerns about the potential side effects of using statins in a large fraction of the population for extended periods. This is true of Asian people, for whom the disease burden from cardiovascular disorders is not as great as among Western ethnic groups. There are still many unanswered questions on how to balance the cardiovascular benefits with the potential renometabolic risks of statins. Therefore, genetic or pharmacogenetic approaches are needed to define who is more vulnerable to developing diabetes mellitus or acute kidney injury. In particular, more information is required regarding the metabolism of statins, and their off-target or unknown actions and overall impact. These different renometabolic effects of statins should help in formulating optimal therapeutic strategies for patients for reducing overall morbidity and mortality and not just those associated with cardiovascular diseases.

Efficacy and safety of aspirin, clopidogrel, and warfarin after coronary artery stenting in Korean patients with atrial fibrillation.

There are limited data on the optimal antithrombotic therapy for patients with atrial fibrillation (AF) who undergoing coronary stenting. We reviewed 203 patients (62.6 % men, mean age 68.3 ± 10.1 years) between 2003 and 2012, and recorded clinical and demographic characteristics of the patients. Clinical follow-up included major adverse cardiac and cerebrovascular events (MACCE) (cardiac death, myocardial infarction, target lesion revascularization, and stroke), stent thrombosis, and bleeding. The most commonly associated comorbidities were hypertension (70.4 %), diabetes mellitus (35.5 %), and congestive heart failure (26.6 %). Sixty-three percent of patients had stroke risk higher than CHADS2 score 2. At discharge, dual-antiplatelet therapy (aspirin, clopidogrel) was used in 166 patients (81.8 %; Group I), whereas 37 patients (18.2 %) were discharged with triple therapy (aspirin, clopidogrel, warfarin; Group II). The mean follow-up period was 42.0 ± 29.0 months. The mean international normalized ratio (INR) in group II was 1.83 ± 0.41. The total MACCE was 16.3 %, with stroke in 3.4 %. Compared with the group II, the incidence of MACCE (2.7 % vs 19.3 %, P = 0.012) and cardiac death (0 % vs 11.4 %, P = 0.028) were higher in the group I. Major and any bleeding, however, did not differ between the two groups. In multivariate analysis, no warfarin therapy (odds ratio 7.8, 95 % confidence interval 1.02–59.35; P = 0.048) was an independent predictor of MACCE. By Kaplan–Meier survival analysis, warfarin therapy was associated with a lower risk of MACCE (P = 0.024). In patients with AF undergoing coronary artery stenting, MACCE were reduced by warfarin therapy without increased bleeding, which might be related to tighter control with a lower INR value.

Predictors of Recovery of Left Ventricular Systolic Dysfunction after Acute Myocardial Infarction: From the Korean Acute Myocardial Infarction Registry and Korean Myocardial Infarction Registry

Background and Objectives We investigated the predictors of the recovery of depressed left ventricular ejection fraction (LVEF) in patients with moderate or severe left ventricular (LV) systolic dysfunction after acute myocardial infarction (MI). Subjects and Methods We analyzed 1307 patients, who had moderately or severely depressed LVEF (<45%) on echocardiography soon after acute MI and who underwent a follow-up echocardiography, among 27369 patients from the Korea Working Group on the Myocardial Infarction Registry. Patients were categorized into two groups according to recovery of LVEF: group I with consistently depressed LVEF (<45%) at the follow-up echocardiography and group II with a recovery of LVEF (≥45%). Results Recovery of LV systolic dysfunction was observed in 51% of the subjects (group II, n=663; ΔLVEF, 16.2±9.3%), whereas there was no recovery in the remaining subjects (group I, n=644; ΔLVEF, 0.6±7.1%). In the multivariate analysis, independent predictors of recovery of depressed LVEF were as follows {odds ratio (OR) [95% confidence interval (CI)]}: moderate systolic dysfunction {LVEF ≥30% and <45%; 1.73 (1.12-2.67)}, Killip class I-II {1.52 (1.06-2.18)}, no need for diuretics {1.59 (1.19-2.12)}, non-ST-segment elevation MI {1.55 (1.12-2.16)}, lower peak troponin I level {<24 ng/mL, median value; 1.55 (1.16-2.07)}, single-vessel disease {1.53 (1.13-2.06)}, and non-left anterior descending (LAD) culprit lesion {1.50 (1.09-2.06)}. In addition, the use of statin was independently associated with a recovery of LV systolic dysfunction {OR (95% CI), 1.46 (1.07-2.00)}. Conclusion Future contractile recovery of LV systolic dysfunction following acute MI was significantly related with less severe heart failure at the time of presentation, a smaller extent of myonecrosis, or non-LAD culprit lesions rather than LAD lesions.

Rosuvastatin dose-dependently improves flow-mediated dilation, but reduces adiponectin levels and insulin sensitivity in hypercholesterolemic patients.

BACKGROUND Genetic analysis from patients participated in the randomized trials reported that the increased risk of type 2 diabetes noted with statins is at least partially explained by HMG-coenzyme A reductase inhibition. We investigated vascular and metabolic phenotypes of different dosages of rosuvastatin in hypercholesterolemic patients. METHODS A randomized, single-blind, placebo-controlled, parallel study was conducted in 48 patients on placebo, and in 47, 48, and 47 patients given daily rosuvastatin 5, 10, and 20mg, respectively during a 2month treatment period. RESULTS Rosuvastatin 5, 10, and 20mg improved flow-mediated dilation (34, 40, and 46%) after 2months therapy when compared with baseline (P<0.001 by paired t-test) and when compared with placebo (P<0.001 by ANOVA). Rosuvastatin 5,10, and 20mg dose-dependently and significantly increased insulin (mean % changes; 19, 29, and 31%, respectively) and glycated hemoglobin levels (mean % changes; 2, 2, and 3%, respectively), and decreased adiponectin levels (mean % changes; 3, 9, and 14%, respectively) and insulin sensitivity (mean % changes; 2, 3, and 4%, respectively) after 2months therapy when compared with baseline (all P<0.05 by paired t-test). These effects with rosuvastatin 5, 10, and 20mg were significant when compared with placebo (P=0.006 for insulin, P=0.012 for glycated hemoglobin, P=0.007 for adiponectin, and P=0.002 for insulin sensitivity by ANOVA). CONCLUSIONS Despite beneficial reductions in LDL cholesterol and improvement of flow-mediated dilation, rosuvastatin dose-dependently and significantly resulted in decreasing insulin sensitivity and increasing ambient glycemia by reducing adiponectin levels and increasing insulin levels in hypercholesterolemic patients.