Enhanced external counterpulsation improves endothelium-dependent vasorelaxation in the carotid arteries of hypercholesterolemic pigs

Enhanced external counterpulsation (EECP) improves biomarkers of glycemic control in patients with non-insulin-dependent type II diabetes mellitus for up to 3 months following treatment

AIMS

The purpose of the present study was to evaluate the potential clinical benefits of EECP on glycemic parameters [fasting plasma glucose (FPG), postprandial glucose (PPG120), glycosylated hemoglobin (HbA1c)] in patients with a clinical diagnosis of type II diabetes mellitus (T2DM).

METHODS

Thirty subjects (60.7 ± 1.9 years) with T2DM were randomly assigned (2:1 ratio) to receive either 35 1-h sessions of EECP (n = 20) or time-matched control of standard care (n = 10). FPG, PPG120, and HbA1c were evaluated before and at 48 h, 2 weeks, 3 and 6 months following EECP treatment or time-matched control.

RESULTS

EECP significantly decreased FPG (-14.6 and -12.0 %), PPG120 (-14.6 and -13.5 %), and HbA1c (-11.5 and -19.6 %) 48 h following EECP and 2 weeks following EECP, respectively. HbA1c remained significantly reduced at 3 months following EECP (-14.3 %). The homeostasis model assessment of insulin resistance (-31.1 %) and whole-body composite insulin sensitivity index (+54.2 %) were significantly improved 48 h following EECP. Nitrite/nitrate (NO x ) was significantly increased 48 h following EECP (+48.4 %) and 2 weeks (+51.9 %) following EECP treatment.

CONCLUSIONS

Our findings provide novel evidence that EECP improves glycemic control in patients with T2DM that persist for up to 3 months following treatment.

Enhanced external counterpulsation inhibits endothelial apoptosis via modulation of BIRC2 and Apaf-1 genes in porcine hypercholesterolemia

OBJECTIVES

Enhanced external counterpulsation (EECP) could improve endothelium-dependent vasodilatation of carotid artery and restore imbalance of nitric oxide and endothein-1 in patients with coronary artery disease. Our study was designed to test the hypothesis that long-term EECP may protect vascular endothelial cells from apoptosis by modifying apoptosis-related gene expression.

METHODS

Eighteen male Yorkshire pigs were randomly assigned to three groups: usual diet (Normal), high cholesterol diet (HC) and high cholesterol diet plus EECP (HC+EECP). Vascular endothelial cells were isolated from the aortic endothelium and identified by CD31 staining and DiI-Ac-LDL reaction. Morphological changes were observed by both scanning and transmission electronic microscopes. TUNEL technique was applied to detect the apoptotic index of vascular endothelial cells. Two genes, Apaf-1 and BIRC2, were chosen for exploring the potential mechanisms of action at the molecular level.

RESULTS

EECP brought a certain degree of alleviation from ultrastructural changes such as shrinking and blebbing of cytomembrane, marginalization, degeneration, and fragmentation of the nucleus. EECP also significantly reduced apoptotic indices while compared with that of control (177±12‰ vs. 237±23‰, P<0.05). The Apaf-1 expression at both protein and mRNA level in pigs of HC+EECP group was significantly decreased than those of the HC group (P<0.05), whereas the BIRC2 expression was significantly enhanced after EECP treatment, documented by immunostaining and semi-quantitative RT-PCR analysis, respectively (P<0.05).

CONCLUSIONS

EECP could protect vascular endothelial cells from apoptosis, thereby delaying the progression of early atherosclerotic lesions possibly through transcriptional down-regulation of pro-apoptotic gene Apaf-1, and up-regulation of anti-apoptotic gene BIRC2.

Exercise-induced Signals for Vascular Endothelial Adaptations: Implications for Cardiovascular Disease

This article reviews recent advances in our understanding of hemodynamic signals, external/compressive forces, and circulating factors that mediate exercise training-induced vascular adaptations, with particular attention to the roles of these signals in prevention and treatment of endothelial dysfunction and cardiovascular (CV) diseases.

Vasculoprotective properties of enhanced external counterpulsation for coronary artery disease: beyond the hemodynamics

A growing pool of evidence has shown that enhanced external counterpulsation (EECP) is a non-invasive, safe, low-cost, and highly beneficial therapy for patients with coronary artery disease. However, the exact mechanisms of benefit exerted by EECP therapy remain only partially understood. The favorable hemodynamic effects of EECP were previously considered as the primary mechanism of action. Nevertheless, recent advances have shed light on the shear stress-increasing effects of EECP which are vasculoprotective and anti-atherosclerotic. EECP-induced endothelial shear stress increase may lead to improvement in endothelial function and morphology, attenuation of oxidative stress and inflammation, and promotion of angiogenesis and vasculogenesis. This review summarizes evidence of the potential mechanisms contributing to the immediate and long-term benefits of EECP, from the perspective of its shear stress-increasing effects.

The effect of enhanced external counterpulsation on C-reactive protein and flow-mediated dilation in porcine model of hypercholesterolaemia

BACKGROUND

Lipid disorder causes vascular endothelial cell damage and contributes to the early development of dyslipidaemia-induced atherosclerosis. In vivo and in vitro, it has been found that increasing shear stress can improve endothelial function. Clinically, enhanced external counterpulsation (EECP) plays important roles in the treatment of coronary artery disease by promoting arterial shear stress. The present study aims to evaluate the effect of EECP on vascular endothelial function in porcine hypercholesterolaemic model.

METHODS

Twenty-six hypercholesterolaemic pigs were equally divided into EECP group (HC-EECP group) and control group (HC group). Shear stress of a right forearm superficial artery was measured during EECP in comparison with the basal physiological status in the HC-EECP group. Endothelial-dependent flow-mediated vasodilation (FMD) was applied to assess endothelial function. Serum high-sensitivity C-reactive protein (hs-CRP) levels were measured at indicated time points.

RESULTS

Endothelial shear stress was increased significantly during EECP treatment (P<0.001). Compared to HC group, hs-CRP decreased significantly by EECP at 18- and 36-h, respectively (P<0.05). FMD was improved significantly by EECP compared to that of HC group at 18 h (11.09 ± 5.63%) and at 36 h (11.42 ± 2.75%) post-EECP, P<0.05. Meanwhile, in animals of HC group, FMD was decreased from baseline 7.76 ± 3.70% to 6.75 ± 3.57% at 18 h and 5.07 ± 1.97% at 36 h, P<0.05.

CONCLUSION

Long-term EECP can improve endothelial function partially by an increased endothelial shear stress in hypercholesterolaemic porcine model. This implies that long-term EECP can be used as a complementary therapeutic strategy to prevent atherosclerosis in hypercholesterolaemic patients.

Effects of enhanced external counterpulsation on arterial stiffness and myocardial oxygen demand in patients with chronic angina pectoris

Enhanced external counterpulsation (EECP) is a noninvasive technique for treatment of symptomatic coronary artery disease in patients not amenable to revascularization procedures. However, the mechanisms underlying the benefits of EECP remain unknown. We hypothesized that decreases in arterial stiffness and aortic wave reflection are a therapeutic target for EECP. Patients with coronary artery disease and chronic angina pectoris were randomized (2:1 ratio) to 35 1-hour sessions of EECP (n = 28) or sham EECP (n = 14). Central and peripheral arterial pulse-wave velocity and aortic wave reflection (augmentation index) were measured using applanation tonometry before, and after 17 and 35 1-hour treatment sessions. Wasted left ventricular pressure energy and aortic systolic tension-time index, markers of left-ventricular myocardial oxygen demand, were derived from the synthesized aortic pressure wave. Exercise duration, anginal threshold, and peak oxygen consumption were measured using a graded treadmill test. Central arterial stiffness and augmentation index were decreased after 17 and 35 sessions in the treatment group. Measurements of peripheral arterial stiffness were decreased after 35 sessions in the treatment group. Changes in aortic pressure wave reflection resulted in decreased measurements of myocardial oxygen demand and wasted left ventricular energy. No changes in central or peripheral arterial stiffness were observed in the sham group. Furthermore, measurements of exercise capacity were improved in the EECP group but unchanged in the sham group. In conclusion, EECP therapy decreases central and peripheral arterial stiffness, which may explain improvements in myocardial oxygen demand in patients with chronic angina pectoris after treatment.

Effect of enhanced external counterpulsation on circulating CD34+ progenitor cell subsets

BACKGROUND

Enhanced external counterpulsation (EECP) is associated with improvement in endothelial function, angina and quality of life in patients with symptomatic coronary artery disease, although the mechanisms underlying the observed clinical benefits are not completely clear. The purpose of this study was to examine the effects of EECP on circulating haematopoietic progenitor cells (HPCs) and endothelial progenitor cells (EPCs) in patients with refractory angina. We compared HPC and EPC counts between patients scheduled for EECP and patients with normal angiographic coronary arteries, with and without coronary endothelial dysfunction. We hypothesized that an increase in circulating bone marrow derived progenitor cells in response to EECP may be part of the mechanism of action of EECP.

METHODS

Thirteen consecutive patients scheduled to receive EECP treatment were prospectively enrolled. Clinical characteristics were recorded and venous blood (5 ml) was drawn on day 1, day 17, day 35 (final session) and one month post completion of EECP therapy. Buffy coat was extracted and HPCs and EPCs were counted by flow cytometry.

RESULTS

Median Canadian Cardiovascular Society (CCS) angina class decreased and Duke Activity Status Index (DASI) functional score increased significantly (both, p < 0.05) in response to EECP, an effect that was maintained at one month after termination of treatment. Flow cytometric analysis revealed an accompanying significant increase in CD34+, CD133+ and CD34+, CD133+ CPC counts over the course of treatment (p < 0.05). DASI scores correlated significantly with CD34+ (R = 0.38 p = 0.02), CD133+ (R = 0.5, p = 0.006) and CD34+, CD133+ (R = 0.47, p = 0.01) CPC counts.

CONCLUSION

This study shows that HPCs, but not EPCs are significantly increased in response to EECP treatment and correlate with reproducible measures of clinical improvement. These findings are the first to link the functional improvement observed with EECP treatment with increased circulating progenitor cells.

Enhanced external counterpulsation treatment improves arterial wall properties and wave reflection characteristics in patients with refractory angina

OBJECTIVES

To determine if arterial properties and wave reflection characteristics are favorably altered after enhanced external counterpulsation (EECP) treatment in patients with refractory angina.

BACKGROUND

Early return of reflected waves from the lower body, resulting from increased arterial stiffness, augments central aortic pressure and increases left ventricular (LV) afterload and myocardial oxygen demand. EECP acutely enhances coronary perfusion (supply) and reduces LV afterload (demand). However, the mechanisms responsible for the sustained beneficial effects of EECP treatment are unclear.

METHODS

Radial artery pressure waveforms were recorded by applanation tonometry and central aortic pressure waveforms generated using a mathematical transfer function in 20 patients with stable refractory angina. Data were collected before and after 34 1-h EECP sessions. Augmentation index (AI(a)) and timing of the reflected pressure wave were calculated from the aortic waveform.

RESULTS

EECP treatment caused a decline in AI(a) and an increase in reflected wave travel time. These modifications in wave reflection characteristics caused a decrease in aortic systolic pressure and wasted LV pressure energy. The average number of angina episodes and Canadian Cardiovascular Society (CCS) class, both decreased in concordance with the physiologic changes due to EECP treatment.

CONCLUSIONS

EECP treatment reduces arterial stiffness and improves wave reflection characteristics in patients with refractory angina. These changes decrease LV afterload and myocardial oxygen demand and reduce the number of angina episodes, therefore enabling patients to participate in continuous exercise programs which in turn may provide long-term benefits and sustained improved quality of life.