Hemodynamics of ventricular-arterial coupling under enhanced external counterpulsation: An optimized dual-source lumped parameter model.

BACKGROUND AND OBJECTIVE: Enhanced external counterpulsation (EECP) is a mechanically assisted circulation technique widely used in the rehabilitation and management of ischemic cardiovascular diseases. It contributes to cardiovascular functions by regulating the afterload of ventricle to improve hemodynamic effects, including increased diastolic blood pressure at aortic root, increased cardiac output and enhanced blood perfusion to multiple organs including coronary circulation. However, the effects of EECP on the coupling of the ventricle and the arterial system, termed ventricular-arterial coupling (VAC), remain elusive. We aimed to investigate the acute effect of EECP on the dynamic interaction between the left ventricle and its afterload of the arterial system from the perspective of ventricular output work. METHODS: A neural network assisted optimization algorithm was proposed to identify the ordinary differential equation (ODE) relation between aortic root blood pressure and flow rate. Based on the optimized order of ODE, a lumped parameter model (LPM) under EECP was developed taking into consideration of the simultaneous action of cardiac and EECP pressure sources. The ventricular output work, in terms of aortic pressure and flow rate cooperated with the LPM, was used to characterize the VAC of ventricle and its afterload. The VAC subjected to the principle of minimal ventricular output work was validated by solving the Euler-Poisson equation of cost function, ultimately determining the waveforms of aortic pressure and flow rate. RESULTS: A third-order ODE can precisely describe the hemodynamic relationship between aortic pressure and flow rate. An optimized dual-source LPM with three energy-storage elements has been constructed, showing the potential in probing VAC under EECP. The LPM simulation results demonstrated that the VAC in terms of aortic pressure and flow rate yielded to the minimal ventricular output work under different EECP pressures. CONCLUSIONS: The ventricular-arterial coupling under EECP is subjected to the minimal ventricular output work, which can serve as a criterion for determining aortic pressure and flow rate. This study provides insight for the understanding of VAC and has the potential in characterizing the performance of the ventricular and arterial system under EECP.

A numerical study on the siphonic effect of enhanced external counterpulsation at lower extremities with a coupled 0D-1D closed-loop personalized hemodynamics model.

Enhanced external counterpulsation (EECP) is a treatment and rehabilitation approach for ischemic diseases, including coronary artery disease. Its therapeutic benefits are primarily attributed to the improved blood circulation achieved through sequential mechanical compression of the lower extremities. However, despite the crucial role that hemodynamic effects in the lower extremity arteries play in determining the effectiveness of EECP treatment, most studies have focused on the diastole phase and ignored the systolic phase. In the present study, a novel siphon model (SM) was developed to investigate the interdependence of several hemodynamic parameters, including pulse wave velocity, femoral flow rate, the operation pressure of cuffs, and the mean blood flow changes in the femoral artery throughout EECP therapy. To verify the accuracy of the SM, we coupled the predicted afterload in the lower extremity arteries during deflation using SM with the 0D-1D patient-specific model. Finally, the simulation results were compared with clinical measurements obtained during EECP therapy to verify the applicability and accuracy of the SM, as well as the coupling method. The precision and reliability of the previously developed personalized approach were further affirmed in this study. The average waveform similarity coefficient between the simulation results and the clinical measurements during the rest state exceeded 90%. This work has the potential to enhance our understanding of the hemodynamic mechanisms involved in EECP treatment and provide valuable insights for clinical decision-making.

Identification of Three Cuproptosis-specific Expressed Genes as Diagnostic Biomarkers and Therapeutic Targets for Atherosclerosis.

Atherosclerosis is a chronic, inflammatory disease characterized by a lipid-driven infiltration of inflammatory cells in large and medium arteries and is considered to be a major underlying cause of cardiovascular diseases. Cuproptosis, a novel form of cell death, is highly linked to mitochondrial metabolism and mediated by protein lipoylation. However, the clinical implication of cuproptosis-related genes (CRGs) in atherosclerosis remains unclear. In this study, genes collected from the GEO database intersected with CRGs were identified in atherosclerosis. GSEA, GO and KEGG pathway enrichment analyses were performed for functional annotation. Through the random forest algorithm and the construction of a protein-protein interaction (PPI) network, eight selected genes (LOXL2, SLC31A1, ATP7A, SLC31A2, COA6, UBE2D1, CP and SOD1) and a vital cuproptosis-related gene FDX1 were then further validated. Two independent datasets (GSE28829 (N = 29), GSE100927 (N = 104)) were collected to construct the signature of CRGs for validation in atherosclerosis. Consistently, the atherosclerosis plaques showed significantly higher expression of SLC31A1, SLC31A2 and lower expression of SOD1 than the normal intimae. The area under the curve (AUC) of SLC31A1, SLC31A2 and SOD1 performed well for the diagnostic validation in the two datasets. In conclusion, the cuproptosis-related gene signature could serve as a potential diagnostic biomarker for atherosclerosis and may offer novel insights into the treatment of cardiovascular diseases. Based on the hub genes, a competing endogenous RNA (ceRNA) network of lncRNA-miRNA-mRNA and a transcription factor regulation network were ultimately constructed to explore the possible regulatory mechanism in atherosclerosis.

Development of Albumin Coupled, Cholesterol Stabilized, Lipid Nanoemulsion of Methotrexate, and TNF-α Inhibitor for Improved In Vivo Efficacy Against Rheumatoid Arthritis.

Methotrexate (MTX; an anti-folate) and etanercept (ET; a TNF-α inhibitor) are used against arthritis; however, limitations like short biological half-life, low cutaneous absorption, and acidic instability limit their clinical relevance. Therefore, the aim of the investigation was to develop albumin coupled lipid nanoemulsion of MTX and ET for improved efficacy by virtue of their controlled release and specificity at the arthritic site. This emulsion was prepared by high-speed homogenization and stabilized using cholesterol. Lipid nanoemulsion of MTX and ET (MTX+ET-LNE) was coupled with albumin (MTX+ET-ALNE). MTX+ET-ALNE was characterized on the basis of particle size (410 ± 25.4 nm), PDI (0.160), and zeta potential (+38.6 ± 5.6 mV) and evaluated for pH (6.15), drug content (97.7 ± 2.17%), entrapment efficiency (76 ± 4.6%), in vitro release, and in vitro cytotoxicity. About 82.6 ± 9.60% release of MTX+ET was observed in 24 h from the developed MTX+ET-ALNE which may help maintain therapeutic level of drugs in blood at least for one day. No toxicity was observed when Raw 264.7 cells were treated with MTX+ET-ALNE, and no causalities of mice were observed at experimental in vivo dose (10 mg/kg BW) of MTX+ET in MTX+ET-ALNE-treated group. MTX+ET-ALNE treatment has alleviated arthritic scores and inflammatory cytokines level in a very significant manner when compared with MTX+ET-LNE and MTX+ET solutions. MTX+ET-ALNE-treated group restored histological alterations (cartilage/bone erosion, inflammatory cell infiltration, synovial hyperplasia, and narrower joint space) as observed in diseased treated groups. In conclusion, MTX+ET-ALNE can be opted as efficacious and clinically pertinent option to the current medication systems of arthritis.

Regulation of microRNA-155 in endothelial inflammation by targeting nuclear factor (NF)-κB P65.

Increasing evidences have illuminated the fundamental role of inflammation in mediating all stages of atherosclerosis. miR-155, a typical multi-functional miRNA, has recently emerged as a novel component of inflammatory signal transduction in the pathogenesis of atherosclerosis. However, little is known about whether endothelial highly expressed miR-155 can regulate endothelial inflammation-related transcription factors and the predicted role of miR-155 as a negative feedback regulator in endothelial inflammation involved in atherosclerosis. Bioinformatics analysis showed that RELA (nuclear factor-κB p65) is a potential target gene of miR-155 and this was confirmed by a luciferase reporter assay. Our results show that microRNA-155 mediate endothelial inflammation and decrease NFкB p65 and adhesion molecule expression in TNFα-stimulated endothelial cells. Transfection with miR-155 significantly inhibited TNFα-induced monocyte adhesion to endothelium. Inhibition of miR-155 enhanced p65 level and endothelial inflammatory response which was counteracted through the depletion of P65 by Si-P65. On the other hand, knockdown of eNOS, another target of miR-155, while transfecting with miR-155 inhibitor resulted in more significant inflammatory response. miR-155 is highly expressed in TNFα treated HUVECs, deprived of endogenous p65 could reverse TNFα-induced upregulation of miR-155. Thus, TNFα induced miR-155 may serve as a negative feedback regulator in endothelial inflammation involved in atherosclerosis by targeting nuclear transcription factor P65. These results provide a rationale for intervention of intracellular microRNA as possible anti-atherosclerotic targets.

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.

Enhanced external counterpulsation improves cerebral blood flow following cardiopulmonary resuscitation.

BACKGROUND: To investigate the therapeutic value of enhanced external counterpulsation (EECP) on recovery of cerebral blood flow following cardiac arrest (CA) and successful resumption of spontaneous circulation (ROSC) by cardiopulmonary resuscitation. METHODS: CA models were conducted using beagle dogs induced by alternating current. After successful ROSC by cardiopulmonary resuscitation, 16 dogs were randomly divided into the EECP and control group (n = 8 per group). Dogs underwent dynamic contrast-enhanced and diffusion-weighted magnetic resonance imaging at baseline prior to CA and during the 3 days following ROSC. Mean blood pressure, right common carotid artery blood flow, intracranial microcirculation and blood lactate levels were measured. Neurological outcome was assessed by the neurologic deficit score. Hematoxylin-eosin staining and transmission electron microscopy were performed for morphology and microconstruction of the cerebral cortex. RESULTS: The EECP group exhibited a significant elevation in right common carotid artery blood flow, intracranial microcirculation and a substantial decrease in blood lactate levels relative to the control group. Relative cerebral blood flow and volume were higher in the EECP group during the 3 days. Apparent diffusion coefficients were significantly higher in the EECP group on the first and third days. After ROSC, the neurologic deficit score was significantly higher in the control group compared to those in the EECP group during the three days of experiment. The cell swelling of neurons and increase of mitochondrial mass were more pronounced in the control group. CONCLUSION: EECP is beneficial for recovery of cerebral blood flow and attenuation of ischemic cerebral edema following CA and successful ROSC.

Transplantation of human umbilical cord-derived endothelial progenitor cells promotes re-endothelialization of the injured carotid artery after balloon injury in New Zealand white rabbits.

BACKGROUND: Cell transplantation has great potential for promoting endothelial repair and reducing the complications of percutaneous coronary intervention (PCI). The aim of this study was to investigate the effect of transplantation of human umbilical cord blood endothelial progenitor cells (EPCs) on injured arteries. METHODS: Umbilical cord blood mononuclear cells were obtained from post-partum lying-in women, and EPCs were isolated, cultured, expanded and identified by immunofluorescence. The carotid arterial endothelium of New Zealand white rabbits was injured by dilatation with a 3F balloon, and the EPCs were injected into the lumen of the injured artery in the transplanted group (n = 16), while an equal volume of phosphated buffered saline (PBS) was injected into the control group after balloon injury (n = 16). The animals were sacrificed after either 2 or 4 weeks, and the grafted cells were identified by double immunofluorescence staining with human nuclear antigen (HNA) and CD31 antibodies. Arterial cross sections were analyzed by pathology, immunohistochemistry and morphometry to evaluate the reparative effects of EPCs. Proliferating cell nuclear antigen (PCNA) and transforming growth factor (TGF)-ß1 mRNA expression were detected by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Fluorescence-labeled EPCs were found in the neointima. The neointimal area and the neointimal/medial area ratio were significantly lower in the transplanted group than in the control group (P < 0.05). von Willebrand factor (vWF) immunohistostaining showed more VWF-positive cells in the transplanted animals than in the controls (8.75 ± 2.92 vs. 4.50 ± 1.77, P < 0.05). Compared with the control group, the transplanted group had lower expression of PCNA mRNA (0.67 ± 0.11 vs. 1.25 ± 0.40, P < 0.01) and higher expression of TGF-ß1 mRNA (1.10 ± 0.21 vs. 0.82 ± 0.07, P < 0.05). CONCLUSIONS: EPCs derived from human umbilical cord blood were successfully transplanted into injured vessels. The transplanted EPCs inhibited neointimal hyperplasia and promoted vascular re-endothelialization.

Early enhanced external counter pulsation improves neurological recovery after the return of spontaneous circulation in a mongrel dog cardiac arrest model*.

OBJECTIVES: The aim of this study was to investigate whether early enhanced external counter pulsation therapy after cardiopulmonary resuscitation improved neurological outcome in a mongrel dog cardiac arrest model. DESIGN: Randomized, animal study. SETTING: Assisted circulation laboratory. SUBJECTS: Twenty-four healthy male adult dogs (12-14 kg). INTERVENTIONS: After minutes of untreated ventricular fibrillation followed by 2 minutes of cardiopulmonary resuscitation, the dogs were randomized to receive 4 hours of enhanced external counter pulsation therapy, to receive 4 hours of hypertension with over 140 mm Hg or to be a control. MEASUREMENTS: Blood pressure and left ventricular ejection fraction were recorded. Cerebral flow was assessed using magnetic resonance imaging. Arterial blood gases and endothelium-derived vasoactive substances were assessed before cardiac arrest and 4 hours after the return of spontaneous circulation. Neurological outcome was assessed by the neurologic deficit score and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining. RESULTS: Enhanced external counter pulsation significantly improved the left ventricular ejection fraction and increased common carotid artery blood flow and shear stress. Enhanced external counter pulsation increased both relative cerebral blood volume (RCBV, p = 0.043) and relative cerebral blood flow (RCBF, p = 0.012) in animals 4 hours after return of spontaneous circulation. Enhanced external counter pulsation therapy promoted the production of nitric oxide and tissue plasminogen activator and decreased the release of endothelin-1 (p = 0.013) after return of spontaneous circulation. Treatment with norepinephrine in the high mean artery pressure also increased common carotid artery blood flow and shear stress. However, no effects on the left ventricular ejection fraction, the production of nitric oxide and tissue plasminogen activator, or the release of endothelin-1 were found. The neurologic deficit scores of the animals were significantly lower at 24, 48, 72, and 96 hours in the enhanced external counter pulsation group, as well as at 24, 72, and 96 hours compared with animals in the control group after return of spontaneous circulation. Fewer apoptotic neurons were observed in the animals in the enhanced external counter pulsation group compared with the animals in the control and hypertension groups. CONCLUSIONS: These data indicated that the treatment of early enhanced external counter pulsation improved neurological outcome by both increasing cerebral blood flow and improving the recovery of microcirculation after return of spontaneous circulation. The treatment of early enhanced external counter pulsation can be a good option for protecting the brain after return of spontaneous circulation.

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.

Defective T wave combined with incomplete right bundle branch block: a new electrocardiographic index for diagnosing atrial septal defect.

BACKGROUND: Incomplete right bundle branch block (ICRBBB) is commonly associated with atrial septal defect (ASD), but lacks sufficient diagnostic test characteristics. An abnormal T wave is also often observed in ASD, with horizontal or inverted displacement of the proximal T wave limb in the right precordial leads, termed "defective T wave" (DTW). METHODS: We examined the diagnostic test characteristics of combining ICRBBB with DTW as a new index to diagnose ASD. A total of 132 consecutive patients with ASD and 132 cases of age/gender-matched controls without ASD were enrolled. RESULTS: Sensitivities of DTW, ICRBBB, and both were 87.1% - 87.9%. Specificities were 97.0%, 96.2%, and 100%, respectively. Positive predictive values were 1.3%, 1.1%, and 100.0% respectively, while negative predictive values were 99.9% for each. CONCLUSION: Combining ICRBBB with DTW in electrocardiogram (ECG) as a new index significantly increased the specificity and positive predictive values while maintaining a high sensitivity in diagnosing ASD.

The changes of brain water diffusion and blood flow on diffusion-weighted and perfusion-weighted imaging in a canine model of cardiac arrest.

OBJECTIVE: To study the changes of brain water diffusion and cerebral haemodynamics of cortical areas using magnetic resonance imaging (MRI) in canine models of cardiac arrest (CA) and restoration of spontaneous circulation (ROSC). The secondary study objective was to evaluate whether MRI can be used to observe haemodynamic disorders in brain microcirculation. METHODS: CA was induced in six beagle dogs using electrical stimulation followed by resuscitation to spontaneous circulation 3 min later. The dogs were scanned using MRI for echo planar, diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) with injection of Gd-diethylene triamine pentaacetic acid (DTPA) prior to induction of CA and 3 days after ROSC. The arterial blood pressure, unilateral common carotid artery flow and intracranial microcirculation were recorded. RESULTS: All dogs successfully underwent electric-induced ventricular fibrillation which lasted 3 min and were resuscitated to maintain blood pressure stability. Serial MRI scans found that cerebral blood flow (RCBF) decreased in day 1 after ROSC and returned to baseline on day 3. Apparent diffusion coefficient (ADC), however, decreased on day 1 and remained lower than baseline on day 3, with 765.8±82.5×10(-6) mm(2) s(-1) on day 1 and 770.4±59.4×10(-6) mm(2) s(-1) on day 3 comparing to 855.8±43.4×10(-6) mm(2) s(-1) on baseline. CONCLUSIONS: These data provide the evidence that early MRI can be used to observe acute haemodynamic disorders in brain microcirculation in a canine model of cardiac arrest.

Pregnancy-associated plasma protein predicts outcomes of percutaneous coronary intervention in patients with non-ST-elevation acute coronary syndrome.

OBJECTIVE: Pregnancy-associated plasma protein A (PAPP-A) may play an important role in the development of acute coronary syndrome. This study aimed to investigate the relationship between the levels of circulating PAPP-A and the mid-term outcomes of percutaneous coronary intervention (PCI) in patients with non-ST-elevation acute coronary syndrome. METHODS: The circulating PAPP-A levels and high-sensitivity C-reactive protein before PCI were measured in 129 patients with single coronary artery stenosis. The end point of clinical follow-up was cardiac death, nonfatal myocardial infarction, target vessel revascularization, and rehospitalization for angina. RESULTS: During the follow-up of an average of 20.3 ± 5.2 months, a cardiac event was recorded in 25 patients (19.4%). The levels of PAPP-A (29.85 ± 19.51 mIu/L vs 20.47 ± 14.33 mIu/L, P = .007) and high-sensitivity C-reactive protein (5.63 ± 2.13 mg/L vs 4.11 ± 1.28 mg/L, P = .014) in patients with cardiac events were higher than in those without cardiac events. PAPP-A ≥ 11.33 mIu/L has a strong predictive value for a combined end point (risk ratio = 4.1; 95% confidence interval, 1.0-16.2; P = .037). Patients with lower PAPP-A levels (<11.33 mIu/L) had higher event-free survivals than patients with higher PAPP-A levels (log rank = 9.334, P = .025). CONCLUSION: Circulating PAPP-A levels predict the mid-term outcomes of PCI in patients with non-ST-elevation acute coronary syndrome and single-vessel stenosis.

Expanded human cord blood-derived endothelial progenitor cells salvage infarcted myocardium in rats with acute myocardial infarction.

1. Cell transplantation has promise as a therapeutic option for restoring impaired heart function after acute myocardial infarction (AMI). However, the optimal cell type to use remains controversial. We investigated the therapeutic efficacy and feasibility of intramyocardial transplantation of human umbilical cord blood-derived endothelial progenitor cells (hUCB-EPC) in rats with AMI. 2. The Wistar rats myocardial infarction model was established by ligating the left anterior descending artery. The labelled hUCB-EPC were transplanted through intramyocardial injection. Left ventricular function was assessed using a pressure-volume catheter and echocardiogram. Anti-VIII immunohistochemistry staining was used to reflect the degree of angiogenesis in peri-infarcted areas by calculating the average capillary density. The fibrosis degree of infarcted myocardium was analysed by Masson staining and the collagen volume fraction was calculated. 3. The labelled donor endothelial progenitor cells were detected in the new microvessels in host myocardium by double-positive staining with CM-Dil and FITC-UEA-l. An increase in left ventricular ejection fraction, left ventricular fractional shortening, left ventricular end-systolic pressure, first derivative of left ventricular pressure (+dP/dtmax and -dP/dtmax), as well as a decrease in the left ventricular end-diastolic pressure in rats with cell therapy indicated a significant improvement in global heart function. The cell therapy group had increased microvessel formation and a decreased degree of myocardial fibrosis compared to the control group. Moreover, the degree of myocardial fibrosis was less than that of the control group. 4. The improved global heart function and decreased cardiac fibrosis in rats with AMI implies the potential benefit of hUCB-EPC transplantation.

Investigation of the relationship between venticular fibrillation duration and cardiac/neurological damage in a rabbit model of electrically induced arrhythmia.

BACKGROUND: To establish a simple, economic, and reliable alternating current (AC)-induced cardiac arrest (ACCA) model in rabbits for cardiopulmonary cerebral resuscitation research. METHODS: Ventricular fibrillation was induced in 27 New Zealand rabbits by external transthoracic AC, which were randomly divided into three groups according to the duration of untreated ACCA (ACCA-3 minutes, ACCA-5 minutes, and ACCA-8 minutes). After ACCA, all animals received cardiopulmonary resuscitation for 2 minutes and subsequent defibrillation until return of spontaneous circulation (ROSC). The troponin I levels were measured at 4 hours after ROSC. Animals died spontaneously or were killed at 72 hours after ROSC. The hippocampus were removed and fixed in 3% formalin. TdT-mediated dUTP-biotin nick end labeling and Nissl stainings were performed in 10-µm thickness coronal sections. Furthermore, two rabbits (without induction of ventricular fibrillation, cardiopulmonary resuscitation, and defibrillation) served as normal control group. RESULTS: Mean survival times after ROSC were 48.57 hours ± 24.70 hours, 18.0 hours ± 15.13 hours, and 3.88 hours ± 2.39 hours for groups ACCA-3 minutes, ACCA-5 minutes, and ACCA-8 minutes, respectively. Survival was significantly different between ACCA-3 minutes and other two groups (p = 0.002 and p = 0.01). Neuronal necrosis and apoptosis were found in the hippocampus CA1, CA2, and CA3 areas of group ACCA-3 minutes. In contrast, neuronal necrosis and TdT-mediated dUTP-biotin nick end labeling positive cells were fewer in control animals. CONCLUSIONS: The rabbits in group ACCA-3 minutes had significant neuronal damage with apoptosis in hippocampus CA1, CA2, and CA3 areas at 72 hours after ROSC and survived longer than those in other groups. The model we describe may be a simple, economic, and reliable model for experimental investigation on cardiopulmonary cerebral resuscitation.

Enhanced external counterpulsation promotes growth cytokines-mediated myocardial angiogenesis in a porcine model of hypercholesterolemia.

BACKGROUND: Enhanced external counterpulsation (EECP) improves ischemia in patients with refractory angina pectoris, but the mechanism remains unclear. To explore the mechanisms of EECP action, we detected progenitor cells presenting any of the following markers CD34(+), CD29(+), and CD106(+). METHODS: Growth cytokines-mediated progenitor cell mobilization and associated angiogenesis potential were assessed in a porcine model of hypercholesterolemia. Twenty-four male domestic swines were randomly assigned to 4 groups: normal diet (control, n = 6), hypercholesterolemic diet (CHOL, n = 6), hypercholesterolemic diet with administration of recombinant human granulocyte colony-stimulating factor (rhG-CSF) (rhG-CSF, n = 6), and hypercholesterolemic diet with EECP treatment (EECP, n = 6). EECP was applied 2 hours every other day for a total of 36 hours. Serum levels of vascular endothelial growth factor (VEGF) and granulocyte colony-stimulating factor (G-CSF), peripheral blood progenitor cell counts, level of regional angiogenesis, and expression of VEGF and stromal cell derived factor 1alpha (SDF-1alpha) in porcine myocardium were assessed, respectively. RESULTS: A porcine model of hypercholesterolemia-induced arteriosclerosis was successfully established. There was no significant difference in serum levels of VEGF among the four groups. The serum levels of G-CSF in the EECP group increased significantly at week 15 and week 18 ((38.3 +/- 5.6) pg/ml at week 15 vs (26.2 +/- 3.7) pg/ml at week 12, P < 0.05, and (46.9 +/- 6.1) pg/ml at week 18 vs (26.2 +/- 3.7) pg/ml at week 12, P < 0.01). The serum levels of G-CSF in group 3 increased also significantly after receiving rhG-CSF injection for five days ((150 +/- 13.9) pg/ml at week 18 vs (24.8 +/- 5.4) pg/ml at week 12, P < 0.01). Compared to other groups and other time points, progenitor cell counts increased significantly after 2-hour EECP treatment (108 +/- 13 vs 26 +/- 6 per 10(5) leukocytes, P < 0.01), but not at week 18. The progenitor cell counts also increased significantly after subcutaneous injection of rhG-CSF for five days compared to the week 12 (baseline) (180 +/- 21 vs 25 +/- 7 per 10(5) leukocytes, P < 0.01). There was no significant difference among the four groups at other time points. Moreover, the expression of VEGF and SDF-1alpha and the level of regional angiogenesis in myocardium increased significantly in both EECP and rhG-CSF groups. CONCLUSIONS: The results demonstrated that EECP could facilitate angiogenesis in the myocardium of atherosclerotic swines by increasing endogenous G-CSF, inducing an enhanced mobilization of progenitor cells and augmenting myocardial expression of VEGF and SDF-1alpha.

Human umbilical cord-derived endothelial progenitor cells promote growth cytokines-mediated neorevascularization in rat myocardial infarction.

BACKGROUND: Cell-based vascular therapies of endothelial progenitor cells (EPCs) mediated neovascularization is still a novel but promising approach for the treatment of ischemic disease. The present study was designed to investigate the therapeutic potentials of human umbilical cord blood-derived EPCs (hUCB-EPCs) in rat with acute myocardial infarction. METHODS: Human umbilical cord blood (hUCB) mononuclear cells were isolated using density gradient centrifugation from the fresh human umbilical cord in healthy delivery woman, and cultured in M199 medium for 7 days. The EPCs were identified by double-positive staining with 1, 1'-dioctadecyl-3, 3, 3', 3'-tetramethylindocarbocyanine percholorate-labeled acetylated low-density lipoprotein (Dil-Ac-LDL) and fluorescein isothiocyanate-conjugated Ulex europaeus lectin (FITC-UEA-l). The rat acute myocardial infarction model was established by the ligation of the left anterior descending artery. The hUCB-EPCs were intramyocardially injected into the peri-infarct area. Four weeks later, left ventricular function was assessed by a pressure-volume catheter. The average capillary density (CAD) was evaluated by anti-VIII immunohistochemistry staining to reflect the development of neovascularization at the peri-infarct area. The graft cells were identified by double immunofluorescence staining with human nuclear antigen (HNA) and CD31 antibody, representing human origin of EPCs and vascular endothelium, respectively. Expressions of cytokines, proliferating cell nuclear angigen (PCNA), platelet endothelial cell adhesion molecule (PECAM) and vascular endothelial growth factor (VEGF) were detected to investigate the underlying mechanisms of cell differentiation and revascularization. RESULTS: The donor EPCs were detectable and integrated into the host myocardium as confirmed by double-positive immunofluorescence staining with HNA and CD31. And the anti-VIII staining demonstrated a higher degree of microvessel formation in EPCs transplanted rats, associated with a significant improvement of global heart function in terms of the increase of left ventricular end-systolic pressure (LVESP), +dp/dtmax and -dp/dtmax as well as the decrease of LVEDP in rats with EPCs therapy comparing to the control rats (P < 0.05). Moreover, the expression of the rat PCNA mRNA and PECAM were both enhanced in the EPCs group compared with that of the control group. CONCLUSIONS: The human umbilical cord blood-derived EPCs could incorporate into new-born capillaries in rat myocardium, induce revascularization and improve the proliferation activity in the peri-infarct area, resulting in the improvement of global heart function. This may indicate a promising stem cell resource in cell-based therapy for ischaemic diseases.

[Effect of external counterpulsation on morphological damage of endomembrane and endothelium-dependent vasodilatation in the carotid arteries in hypercholesterolemic pigs].

OBJECTIVE: To explore the effect of long-term enhanced external counterpulsation (EECP) on morphological damage of endomembrane and endothelium-dependent vasodilatation of the carotid arteries of hypercholesterolemic pigs. METHODS: Eighteen male infant pigs were randomly divided into three groups according to the contents of their diet: the normal control group (n=6), the high-cholesterol feeding control group (n=6) and EECP group (n=6). Porcine model of hypercholesterolemia was reproduced by feeding animals with high-cholesterol diet. After completion of EECP treatment for 36 hours in EECP group, carotid arterial rings were harvested from all animals. Both scanning and transmission electron microscopy was employed to observe the changes in morphology of their endomembrane. At the same time, their vasodilatation response to variant dose of acetylcholine (Ach) was detected. RESULTS: The surface of endothelium in the normal control group was smooth, and endothelial cells were in regular streamline array, and they were almost in same size, attaching closely to matrix without smooth muscle cell proliferation and lipid infiltration in intima. In contrast, the endothelial cells of hypercholesterolemic pigs were in irregular array, with marked desquamation, resulting in loose linkage. Smooth muscle cells were found to invade into intimal layer and proliferated, and foam cells could also be found in intimal layer. In hypercholesterolemic pigs treated with EECP, slight intimal damage was found. In addition, with Ach dose of 10(-8) mol/L to 10(-5)mol/L, endothelium-dependent vasodilatation ratio in hypercholesterolemic pigs with or without EECP treatment, was significantly lower than that of the normal control group (all P<0.05). However, endothelium-dependent vasodilatation ratio in pigs with EECP treatment was obviously higher compared with hypercholesterolemic pigs without EECP treatment with the dosage of Ach concentration ranged from 10(-7) mol/L to 10(-5) mol/L (all P<0.05). CONCLUSION: Long-term EECP ameliorates both the morphological damage and the impaired endothelium-dependent vasodilatation function resulting from hypercholesterolemia, contributing to prevention of atherosclerosis.

[Effect of chronic enhanced external counterpulastion on gene expression profiles of arterial endothelial cells of pigs fed with high-cholesterol diet].

OBJECTIVE: To investigate the effect of chronic enhanced external counterpulastion (EECP) on gene expression profiles of arterial endothelial cells (ECs) of pigs fed with high-cholesterol diet. METHODS: Eight male pigs were fed with high-cholesterol diet for 12 weeks to induce arteriosclerosis and subjected to EECP for accumulative 36 h (2 h every other day for 18 sessions). Another 8 pigs on cholesterol-enriched diet and 6 normally fed pigs served as the arteriosclerosis model group and normal control group, respectively, and the high-cholesterol diet was maintained until the end of EECP treatment. The coronary artery was then isolated for transmission electro microscopy, and the abdominal aorta was observed using Sudan III staining. The gene expression profiles in ECs from the thoracic aorta using cDNA microarrays. RESULTS: Macrophages and foam cells were detected beneath the ECs in the coronary artery of pigs in the model group, but not in the other two groups. The ratios of Sudan III-positive area in the celiac aorta were significantly lower in normal control and EECP groups than in the model control group (P<0.05). Compared with the normal control group, the gene expressions of integrins-beta1 and CTGF were up-regulated in the model group. Compared with the model group, the expressions of integrins-beta1, CTGF and VCAM-1 were down-regulated and eNOS up-regulated in EECP group. CONCLUSION: Chronic EECP may reduce endothelial injury, down-regulate the gene expression level of integrin-beta1, CTGF and VCAM-1, lower cholesterol uptake and attenuate arterial endothelial inflammation to protect the pigs fed with high-cholesterol diet from arteriosclerosis.

Effects of B-type natriuretic peptide (nesiritide) on coronary epicardial arteries, systemic vasculature and microvessels.

BACKGROUND: Nesiritide is recombinant human B-type natriuretic peptide, used in the treatment of decompensated heart failure. Ischemic heart disease remains the major underlying cause for congestive heart failure, however, the effects of intravenous and intracoronary nesiritide on coronary circulation have not been adequately studied. METHODS: Fourteen Yorkshire pigs were used to systematically evaluate the effects of intravenous and intracoronary nesiritide on microvascular function, coronary blood flow, and epicardial and microvascular reactivity using in vivo hemodynamic parameters, Doppler flow assessment (average peak velocity, APV) and intravascular ultrasound (cross-sectional area, CSA), and in vitro microvascular function. RESULTS: The clinically used dose of nesiritide caused a small (not statistically significant) decrease in blood pressure at 10 minutes (p = 0.6411); blood pressure returned to baseline at 30 minutes and did not affect coronary flow or diameter. Intracoronary nesiritide (100 mcg) resulted in a slight increase (trend) in coronary flow (increase from 15.8 to 19 cm/s; p = 0.6), but no change in CSA. Nesiritide caused significant microvascular relaxation in vitro (p = 0.009), attenuated by pretreatment with L-NAME indicating that vasodilation is partially nitric oxide-dependent. CONCLUSIONS: Intravenous and intracoronary nesiritide do not result in adverse effects on the normal coronary circulation in pigs. In contrast it has profound effects on microvessels with potentially beneficial effects on the myocardial perfusion at the tissue level. Further studies are needed to assess its effects on diseased coronary circulation and its safety in patients with ischemic heart disease.