Study of the three-dimensional structure of the ventricular myocardial fiber in human heart / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the three-dimensional structure of ventricular myocardial fiber in human heart.</p><p><b>METHODS</b>Eight human heart were obtained from male donors aged 81.9-/+7.2 years with a heart weight of 455.6-/+65.7 g. Each sample was immersed in water and scanned by diffusion tensor magnetic resonance imaging (DT-MRI) using a 3 Tesla Exicte HD by an eight-channel head coils. The duration was 18.6-/+5.2 h from heart arresting to the scanning. The data were obtained using the protocol of single shot echo planar imaging (sshEPI) and sensitivity encoding (SENSE). The SENSE-sshEPI-scans (TE/TRZ86.4/2000 ms) of the whole heart were carried out (b=1000 s/mm(2), voxels 128x128, resolution 1.1 mmx1.1 mmx(3) mm, and FOV 14 cmx14 cm). Fiber tracking and reconstruction were performed using GE Advantage Windows Workstation. The three-dimensional structure of the ventricular myocardial fiber was observed.</p><p><b>RESULTS</b>The left ventricular myocardial fibers showed two layers with different directions of alignment in such regions as the anterior, septum, and posterior walls and the free left ventricular wall. The subendocardial layer ran obliquely from the base to the apex, and the middle layer ran obliquely upward from the base to the apex. The two layers were linked together and aligned in the pattern of helical coils near the apex.</p><p><b>CONCLUSIONS</b>The three-dimensional structure of the myocardial fibers in human heart conforms to Torrent's hypothesis of helical ventricular myocardial band (HVMB).</p>

Improvement in cardiac function after sarcoplasmic reticulum Ca2+-ATPase gene transfer in a beagle heart failure model / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Heart failure (HF) is a major cause of morbidity and mortality worldwide, but current treatment modalities cannot reverse the underlying pathological state of the heart. Gene-based therapies are emerging as promising therapeutic modalities in HF patients. Our previous studies have shown that recombinant adeno-associated viral (rAAV) gene transfer of Sarco-endoplasmic reticulum calcium ATPase (SERCA2a) can be effective in treating rats with chronic heart failure (CHF). The aim of this study was to examine the effects of SERCA2a gene transfer in a large HF animal model.</p><p><b>METHODS</b>HF was induced in beagles by rapid right ventricular pacing (230 beats/min) for 30 days. A reduced rate ventricular pacing (180 beats/min) was continued for another 30 days. The beagles were assigned to four groups: (a) control group (n = 4); (b) HF group (n = 4); (c) enhanced green fluorescent protein group (n = 4); and (d) SERCA2a group (n = 4). rAAV1-EGFP (1 x 10(12) microg) and rAAV1-SERCA2a (1 x 10(12) microg) were delivered intramyocardially. SERCA2a expression was assessed by Western blotting and immunohistochemistry.</p><p><b>RESULTS</b>Following 30 days of SERCA2a gene transfer in HF beagles its protein expression was significantly higher than in the HF group than in the control group (P < 0.05). Heart function improved along with the increase in SERCA2a expression. Left ventricular systolic function significantly improved, including the ejection fraction, left ventricular systolic pressure, maximal rate of rise of left ventricular pressure (+dp/dt(max)), and the maximal rate of decline of left ventricular pressure (-dp/dt(max)) (P < 0.05). Left ventricular end-diastole pressure significantly decreased (P < 0.05). The expression of SERCA2a in the myocardial tissue was higher in the SERCA2a group than in the HF group (P < 0.05).</p><p><b>CONCLUSIONS</b>Intramyocardial injection of rAAV1-SERCA2a can improve the cardiac function in beagles induced with HF. We expect further studies on SERCA2a's long-term safety, efficacy, dosage and the optimization before using it in humans with HF.</p>

Overexpression of sarcoplasmic reticulum calcium ATPase induced hemodynamic and proteomic changes in a dog model of heart failure / 中华心血管病杂志

<p><b>OBJECTIVE</b>Overexpression of SERCA2a could improve cardiac function in human and experimental heart failure (HF) models. We observed the proteomics changes post SERCA2a overexpression in a pacing induced HF model in dogs.</p><p><b>METHODS</b>Beagles were divided into four groups: control group, HF group (230 beats/min for 4 weeks), HF + EGFP group (myocardial injection of 1 x 10(12) v.g recombinant adeno-associated virus carrying enhanced green fluorescent protein gene, rAAV2/1-EGFP) and HF + SERCA2a group (myocardial injection of 1 x 10(12) v.g recombinant adeno-associated virus carrying SERCA2a gene, rAAV2/1-SERCA2a). Thirty days after gene transduction, left ventricular systolic and diastolic functions were measured by echocardiography and invasive hemodynamics in all animals. By use of 2-dimensional gel electrophoresis (2-DE), -500 distinct protein spots were detected in myocardium of all animals. Protein spots observed to be altered between failing and SERCA2a overexpressed hearts were subjected to tryptic peptide mass fingerprinting for identification by MALDI-TOF mass spectrometry in combination with LC/MS/MS analysis.</p><p><b>RESULTS</b>At 30 day after gene transfer, HF signs were significantly reduced, cardiac function [LVSP: (214.72 +/- 31.74) mm Hg (1 mm Hg = 0.133 kPa) vs. (139.32 +/- 36.79) mm Hg, +dp/dt(max): (6779.43 +/- 217.58) mm Hg/s vs. (2746.85 +/- 931.23) mm Hg/s and -dp/dt(max): (-4341.42 +/- 322.02) mm Hg/s vs. (-2531.14 +/- 616.15) mm Hg/s, LVEDP: (21.86 +/- 6.95) mm Hg vs. (59.78 +/- 6.92) mm Hg] significantly improved in HF + SERCA2a dogs than those in HF + EGFP group(all P < 0.05) and parameters were comparable between HF + SERCA2a and control groups. We identified alterations in the expression level of more than 10 proteins in myocardium. These protein changes were observed mainly in two subcellular compartments: the cardiac contractile apparatus and metabolism/energetics.</p><p><b>CONCLUSION</b>These results showed that overexpression of SERCA2a could improve cardiac function accompanied with numerous alterations in protein expressions involved in calcium handling, myofibrils, and energy production in this dog model of chronic heart failure.</p>

Diagnostic study on the coronary artery bypass grafts lesions using 64 multi-slice computed tomography angiography / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the diagnostic accuracy in the assessment of coronary artery bypass grafts using 64 multi-slice computed tomography angiography (64-MSCTA) technology.</p><p><b>METHODS</b>There were 228 patients post coronary artery bypass grafting (CABG) underwent 64-MSCTA from July 2005 to April 2007. Thirty-one patients with 82 bypass grafts performed coronary angiography (CAG) because of angina or grafts lesion showed by 64-MSCTA.</p><p><b>RESULTS</b>All bypass grafts could be visualized by 64-MSCTA. Thirteen bypass graft occlusions and fourteen significant stenosis were detected by 64-MSCTA and confirmed by CAG. One venous grafts distal anastomosis was missed and another one was miss diagnosed as stenosis. One false negative and one false positive CT-finding resulted in a sensitivity of 93.3%, a specificity of 98.1%, a positive predictive value of 93.3%, a negative predictive value of 98.1% and an accuracy of 97.1% for grafts stenosis. As to the grafts lesion, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy for grafts occlusion were 96.4%, 98.1%, 96.4%, 98.1% and 97.6%, respectively.</p><p><b>CONCLUSION</b>64-MSCTA demonstrates high diagnostic accuracy in the assessment of graft patency and suitable for the follow-up of patients post CABG.</p>