Objective To investigate the feasibility and effect of stentedpulmonary autograft replacement and find out the best way to treat mitral valve diseases. Methods From August 2006 to October 2007, 20 male sheep at the age of about 1 year old underwent mitral valves replacement operation in Anzhen Hospital. Weight of these sheep was 50.0±6.0 kg. They were randomly divided into two groups. Ten sheep in the experimental group underwent RossⅡsurgery in which we first sutured pulmonary valve onto a pulmonary valve stent, transferred the valve to the mitral valve annulus and then reestablished the outflow tract of the right ventricle. The other 10 sheep in the control group underwent bioprosthetic valve replacement routinely. Ultrasonic cardiogram (UCG) was employed 6 hour after operation to measure the effective orifice area (EOA) of the mitral valve, mitral peak velocity of early filling, the peak pressure gradient (PPG), the extent of regurgitation, left ventricular enddiastolic dimension (LVEDD) and ejection fraction (EF). Results One sheep in the experimental group died of low cardiac output syndrome; one in the control group died of unmanageable bleeding during operation, and the others all survived. Six hours after operation, UCG of the experimental group showed that the heart valves were well fixed, valve echo was clear, and there was no perivalvular leakage or mitral valve stricture or regurgitation, but moderate pulmonary valve regurgitation occurred in 1 case and mild in 2. There was no significant difference between the two groups in PPG (11.86±1.28 mm Hg vs. 10.98±0.98 mm Hg,t= 1.670,P=0.110) and the mitral peak velocity of early filling (1.72±0.09 m/s vs. 1.65±0.07 m/s, t=1.680,P=0.110). However, EOA of the experimental group was smaller than the control group (2.23±0.09 cm2 vs. 2.39±0.08 cm2, t= 4.240,P= 0.001). Conclusion The experimental result of sheep mitral valves replacement with stentedpulmonary autograft is satisfying. The new mitral valves work well and the surgery method is feasible.
Abstract: The amniotic fluidderived stem cells (AFSC) possess considerable advantageous characteristics including high proliferation potential, easy availability, low immunogenicity and oncogenicity，and accordance with medical ethnics. Moreover, they do not require the sacrifice of human embryos for their isolation and the cells can differentiate into all three kinds of germs. Accordingly，they initiate a new and very promising field in stem cell research and they will be a potential source of stem cells for therapies related to regeneration medicine of cardiovascular diseases. The research about the AFSC utilization in cardiovascular diseases is just started. Though there were some exciting breakthroughs, there still remain many challenges. In the article，we will discuss AFSC characteristics, influence of amniotic fluid harvesting time on stem cells, isolation and purification, emphasizing mainly on the potential of AFSC differentiation into cardiovascular cells, current situation and problems in this field.
Objective To report a reliable left heart failure model in sheep using selected ligation of the diagonal branch. Methods Four male sheep were used. After a left anterior thoracotomy in sheep, the diagonal branch of coronary artery was ligated at a point approximately 40% of the distance from the apex to the base of the heart. Hemodynamic and echocardiography measurements were done preligation, 30 minutes and 7 days after the coronary artery of diagonal branch ligation. The electrocardiograms were obtained as needed, and cardiac function was also evaluated. The sheep were killed for postmortem examination of their hearts. Results Four sheep survived the experimental procedures. Comparing with before surgery, systemic arterial blood pressure and cardiac output were decreased, pulmonaryartery systolic pressure, pulmonary capillary wedge pressure and central venous pressure were increased at 30 min and 7 days after selected ligation of the coronary artery of diagonal branch; left ventricular end-diastolic dimension and left ventricular end-systolic dimension were increased; left ventricular ejection fraction and left ventricular fractional shortening were also decreased (Plt;0.05). Conclusion A reliable ovine model of left ventricular failure using selected ligation of the diagonal branch of the coronary artery can be achieved. This animal model is comparable to the clinical correlation.
Objective To review the latest development of amniotic fluid-derived stem cells (AFSCs) in regenerative medicine, and to discuss issues related to the studies in the field of AFSCs. Methods The recent articles about AFSCs were extensively reviewed. The important knowledge of AFSCs was introduced in the field of regenerative medicine, and the basic and clinical researches of AFSCs were summarized and discussed. Results Currently, it is confirmed that AFSCs have a multi-directional differentiation capacity, therefore, they have a wide application prospect in regenerative medicine, anti-tumor, and other fields. Conclusion AFSCs will become one of the ideal seed cells in the field of regenerative medicine with extensive research value because of the advantages of easy amniotic fluid sampling, little maternal and child trauma, no tumorigenesis, and no ethical restrictions.
Objective To investigate the feasibility and effect of human amniotic membrane in prevention of tendon adhension after tendon sheat defect repair. Methods The amniotic membrane in size of 1.5 cm × 1.0 cm was harvested from human placenta which was voluntary donated from maternal after cesarean. Forty healthy male Leghorn chicken (aged 3-6 months) were selected, weighing (1.86 ± 0.04) kg. The model of flexor digitorum profundus tendon and tendon sheath defects was established at the third toe. After repair of the flexor digitorum profundus tendon, the human amniotic membrane was used to repair the tendon sheath defect in the right foot (group A), but tendon sheath defect was not repaired in the left foot (group B) . At 1, 2, 4, and 6 weeks after operation, the gross and histological observations were done; the degree of tendon adhesions was graded according to Tang’s tendon adhesion general observation grading standards; and the biomechanical properties (tendon slip length and total flexion angle) were tested. Results All animals survived after operation and incisions healed. Gross and histological observations showed that the new tendon sheath formed with time passing after operation in groups A and B; new tendon sheath was more maturer and smoother in group A than in group B. The degree of tendon adhesions in group A was significantly less than that in group B (P lt; 0.05) at 1 and 6 weeks after operation. The biomechanical test results showed there was no significant difference in the tendon slip length between 2 groups at 1 and 2 weeks after operation (P gt; 0.05), but the tendon slip length of group A was significantly longer than that of group B at 4 and 6 weeks after operation (P lt; 0.05). The total flexion angle of group A was significantly smaller than that of group B at 1, 2, 4, and 6 weeks after operation (P lt; 0.05). Conclusion It is effective in the prevention of tendon adhesion to use the amniotic membrane for repairing the tendon sheath defect, which is beneficial to recovery of the tendon sliding function.
Objective To establish a rapid, simple, and economic method to prepare osteoporosis (OP) in vitro model. Methods Eighty pairs of fresh goat femur were collected from 18-month-old female goats and were randomly divided into 4 groups (20 pairs in each group). The femur was immersed decalcifying solution (18% EDTA) for 1-5 days (group B), 6-10 days (group C), and 11-15 days (group D), while group A had no treatment as control. Four pairs of femur were taken out every day. Quantitative computed tomography was used to scan the medial and lateral femoral condyles, and the bone mineral density (BMD) was calculated. Electronic universal testing machine was used to do three-point bending test and compress and tensile ultimate strenght test, and the mechanical parameters for femur were calculated. Results With demineralized time passing, BMD of the medial and lateral femoral condyles were downtrend in groups A, B, C, and D, showing significant differences among 4 groups (P lt; 0.05); BMD of the lateral femoral condyle was significantly higher than that of the medial femoral condyle in each group (P lt; 0.05). The three-point bending test showed that broken load, ultimate strength, and elastic modulus of groups A and B were significantly higher than those of groups C and D (P lt; 0.05); but no significant difference was found between groups A and B, and between groups C and D (P gt; 0.05). Compress and tensile ultimate strength test showed that the compress and tensile ultimate strengths were significantly higher in group A than in groups C and D (P lt; 0.05), and in group B than in group D (P lt; 0.05), but no significant difference was found between groups A and B, between groups B and C, and between groups C and D (P gt; 0.05). Conclusion The 18% EDTA immersing for 6-15 days is a fast, simple, economical method to prepare an OP in vitro model of goat femur.
Objective To evaluate the influence of PKH26 labeling on the biological function of the goat nucleus pulposus cells and the biological function of seeded cells in nude mice by in vivo imaging techonology. Methods Primary nucleus pulposus cells were isolated by enzymatic digestion from the nucleus pulposus tissue of the 1-year-old goat disc. The nucleus pulposus cells at passage 1 were labeled with PKH26 and the fluorescent intensity was observed under the fluorescence microscopy. The labeled cells were stained with toluidine blue and collagen type II immunocytochemistry. The cells viability and proliferation characteristics were assessed by trypan blue staining and MTT assay, respectively. Real-time fluorescent quantitative PCR was used to detect the gene expressions of collagen types I and II, and aggrecan. The fluorescent intensity and scope of the nucleus pulposus cells-scaffold composite in vivo for 6 weeks after implanting into 5 6-week-old male nude mice were measured by in vivo imaging technology. Results Primary nucleus pulposus cells were ovoid in cell shape, showing cluster growth, and the cells at passage 1 showed chondrocyte-like morphology under the inverted phase contrast microscope. The results of toluidine blue and collagen type II immunocytochemistry staining for nucleus pulposus cells at passage 1 were positive. The fluorescent intensity was even after labeling, and the cell viability was more than 95% before and after PKH26 labeling. There was no significant difference in cell growth curve between before and after labeling (P gt; 0.05). The real-time fluorescent quantitative PCR showed that there was no significant difference in gene expressions of collagen types I and II, and aggrecan between before and after labeling (P gt; 0.05). Strong fluorescence in nucleus pulposus cells-scaffold composite was detected and by in vivo imaging technology. Conclusion The PKH26 labeling has no effect on the activity, proliferation, and cell phenotype gene expression of the nucleus pulposus cells. A combination of PKH26 labeling and in vivo imaging technology can track the biological behavior of the cells in vivo.