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BACKGROUND:In recent years, endoplasmic reticulum stress-caused apoptosis plays a crucial role in ischemia impairment and has become the hotspot of studies addressing myocardial ischemia/reperfusion (I/R) injury. The lower limb ischemic preconditioning (LIP) has the obvious protective effect on the immature myocardium, but until now, no study reports whether LIP effects on endoplasmic reticulum stress apoptosis in immature myocardial cells. OBJECTIVE:To investigate the effect of LIP on endoplasmic reticulum stress and apoptosis. METHODS:Langendorff-perfused isolated rabbit hearts were used in this study. Twenty-four immature rabbits were randomized into three groups. Control group:Isolated rabbit heart was only perfused with Krebs-Henseleit for 180 minutes. I/R group:Isolated rabbit heart was perfused 20 minutes, and then ischemia for 60 minutes fol owed by reperfusion 100 minutes. LIP group:Limbs were repeatedly obstructed 5 minutes and relaxed 5 minutes for three times, to establish Langendorff models, and then repeated the method of ischemia/reperfusion in I/R group. The myocardial apoptosis was assayed with TUNEL method. The expression of glucose-regulated protein 78, Bcl-2, Bax and Fas was detected with western blot analysis. RESULTS AND CONCLUSION:Compared with I/R group, apoptosis rate was significantly lower, the expression of Bcl-2 was significantly higher, and the expression of glucose-regulated protein 78, Bax and Fas was significantly lower in LIP group. This study demonstrated that LIP regulates myocardial cellapoptosis through reducing the expression of endopasmic reticulum stress GRP78, Bax and Fas and increasing the expression of Bcl-2.
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BACKGROUND: How to successfully obtain compact endothelium layers on smooth muscle cells is the most crucial part for the tissue-engineered vessels. OBJECTIVE: To explore the effects of different cell implantation concentrations on the construction of the complete biological tissue-engineered blood vessels.METHODS: Different concentrations of porcine vascular smooth muscle cells (5×105, 5×107 cells/L) were implanted on the porcine acellular vascular matrix to culture for 3 days. Then different concentrations of endothelial progenitor cells (5×105, 5×107 cells/L) were implanted on the smooth muscle cell-vascular matrix composite to construct lamellar complete biological tissue-engineered blood vessels.RESULTS AND CONCLUSION: The growth curves of high concentrations of smooth muscle cells on the acellular vascular matrix were similar to that of low concentrations. Moreover, the growth curves of cells implanted in the culture plates were similar to that implanted on the acellular matrix. However, cells in the low concentration groups have relatively low proliferation activity and low coverage rate. The cell coverage rate decreased as follows: high concentrations of endothelial progenitor cells+acellular matrix containing high concentrations of smooth muscle cells > high concentrations of endothelial progenitor cells+acellular matrix containing low concentrations of smooth muscle cells > low concentrations of endothelial progenitor cells+acellular matrix containing high concentrations of smooth muscle cells > low concentrations of endothelial progenitor cells+acellular matrix containing low concentrations of smooth muscle cells. Moreover, high concentrations of endothelial progenitor cells form relatively compact layers on the acellular matrix and show cobble-like growth. These findings indicate that an increase in the cell implantation concentrations is beneficial to the rapid formation of compact cell layers on the material surface.
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BACKGROUND: Heart valve tissue engineering is aimed to construct heart valve grafts with the physiological function and biological activity by using engineering and life science principles and methods, but still in the animal experiment stage.OBJECTIVE: To summarize the commonly used tissue engineered heart valve, and to evaluate the reliability of different types of heart valve biomaterials.METHODS: Using "biological materials, heart valve, scaffolds, reviews, tissue engineering" in Chinese as the key words, a computer retrieval was performed for articles published from January 2000 to December 2010. Articles regarding the biomaterials in tissue engineered heart valve were included; the duplicated research or meta-analysis were excluded.RESULTS AND CONCLUSION: A total of 20 papers about the biomaterials and tissue engineering heart valve were screened out. Due to the superior biocompatibility and three-dimensional conformation, natural scaffold materials exhibit unparalleled bionic property compared with other materials. Synthetic biodegradable polymer materials with good mechanical properties and controllability has thus been highly favored by researchers, while the composite scaffold materials of natural materials and polymer materials provides a new strategy and direction for the investigations of tissue engineered heart valve, and has broad application prospects.
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Objective To study the curative effect of continuous veno-venous hemodiafiltration(CVVH)in patients with acute renal failure(ARF)after aortic dissection surgery. Methods Fifteen patients with renal dysfunction following aortic dissection surgery underwent CVVH from Feb. 2002 to Dec. 2009 in this study.The clinical data of these patients were collected,such as heart rate(HR),central vein pressure(CVP),mean artery blood pressure(MAP),PaO2,renal function,perioperative manifestations and outcomes. Results Eleven patients survived but 4 died during the course of treatment. There were significant decreases of BUN,Creatinin after CVVH (P ＜ 0. 05)treatment,and the urine volume returned to nomal after CVVH in 6 -40 days. Conclusions CVVH is an effective,convenient and safe treatment for patients with severely ARF following aortic dissection surgery.
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Objective To investigate the synthesis of heat shock protein 70 (HSP70) induced by norepinephrine preconditioning on donor heart and its effects on myocardial cell apoptosis and apoptosis related proteins. Methods 18 Wistar rats were random divided into 2 groups, with 9 in each group. The rats in the control group were intraperitoneally injected with 0.5 ml saline. After 24 hours, hearts were isolated and stored with histidine-tryptophan-ketoglutarate (HTK) solution at 4 ℃ for 3 hours to establish Langendorff isolated heart models, and then isolated hearts were perfused by Langendorff model with Krebs-Hense leit (K-H) solution for 2 hours. The rats in the experimental group received intraperitoneally 3. 1 μmol/kg (0. 53 mg/kg) noradrenaline bitartrate that was dissolved in saline and hearts were isolated and stored after 24 hours. Followed process was the same as that in the control group. Myocardial HSP70, Bcl-2, Bax content, apoptosis index were measured, cell structures were observed under light and electron microscope.Results HSP70 in the experimental group were higher [(17.78 ± 1.82)%] than those in control group [(5.22 ± 1.05)%], and biochemical indicators in texperimental group[(41.88 ± 5.09)%, (22.61 ±3. 49 ) %] were better than those in control group [(31.36 ± 3. 27 ) %, ( 40. 52 ± 4. 1 7) %]. There were alleviated ultrastructure injures in experimental group compared with those in control group. Conclusions This study demonstrated that norepinephrine preconditioning could induce high expression of HSP70 and it could play a very important role during ischemia-reperfusion. It could protect the structure and function of myocytes in isolated rat hearts and inhibited myocardial apoptosis.
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BACKGROUND:Changes of both stem cell markers and endothelial cell phenotype help understand characteristics of endothelial progenitor cells during adherent differentiation.However,there is still no specific cell marker to distinguish from mature endothelial cells.OBJECTIVE:To study the changes of stem cell markers and endothelial cell phenotype during the differentiation of rat peripheral blood rnononuclear cells into endothelial cells.DESIGN.TIME AND SETTING:Cell observation study was performed in the Laboratory of Cardiac Surgery,Qingdao Municipal Hospital between June 2004 and December 2008. MATERIALS:Peripheral blood was drawn from male SD rats to obtain mononuclear cells by Ficell density gradient centrifugation. METHODS:Mononuclear cells were in vitro cultured in fibronectin culture medium and induced by vascular endothelial growth factors(VEGF)and basic fibroblast growth factors(bFGF)in order to stimulate a differentiation into endothelial cells. MAIN OUTCOME MEASURES:Adherent cells in the culture system were identified for CD31,CD34,Rk-1 and vWF with immunochemistry within 1-7 days.RESULTS:The expressions of CD31.CD34,FIk-1.vWF on adherent cells were different in different time durations.The expressions of CD31 and CD34 started on the 2nd day of culture.reached the peak on the 4th day,gradually decreased and even disappeared on the 6thday.While.FIk-1 expressed on the 3rd day of culture,gradually increased,and reached at the peak on the 7th day.vWF expressed gradually until 100%on the 7th day. CONCLUSION:The differentiation of peripheral blood stern cells into endothelial progenitor cells is characterized by the appearance of endothelial cell phenotypes and the disappearance of stern cell markers.both in the manner of gradual progression.
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To investigate the effects of metallothionein (MT) on isolated rat heart, 16 Wistar rats were randomly divided into 2 groups. In control group (group C), distilled water was injected intraperitoneally and 24 h later isolated hearts were perfused with Langendorff and stored at 4 degrees C for 3 h with histidine-tryptophan-ketoglutarate (HTK) solutions, and then isolated hearts were perfused for 2 h by Langendorff. In experimental group (group E), 3.6% ZnSO(4) was injected intraperitoneally, 24 h later isolated hearts were perfused by Langendorff and stored at 4 degrees C for 3 h with HTK solutions, and then the isolated hearts were perfused for 2 h with Langendorff. MT content, the recovery of hemodynamics, myocardial water content (MWC), lactate dehydrogenase (LDH) and creatine kinase (CK) leakage, adenosine triphosphate (ATP) and malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, myocardial cell Ca(2+) content, Ca(2+)-ATPase activity of mitochondria ([Ca(2+)-ATPase](m)) and its Ca(2+) content ([Ca(2+)](m)), synthesizing ATP activity of mitochondria ([ATP](m)), and the ultrastructure of cells were examined. There were a significant increase in group E in hemodynamic recovery, ATP content, SOD activity, [Ca(2+)-ATPase](m) activity, [ATP](m) activity, and substantial reduction in MWC, LDH and CK leakage, MDA content, myocardial cell Ca(2+) content, [Ca(2+)](m) content, and the ultrastructural injury were obviously milder than that of group C. This study demonstrated that MT has protective effects on isolated rat heart.
Subject(s)
Cardiotonic Agents/pharmacology , Creatine Kinase/metabolism , L-Lactate Dehydrogenase/metabolism , Metallothionein/biosynthesis , Metallothionein/pharmacology , Myocardium/metabolism , Myocardium/ultrastructure , Random Allocation , Rats, Wistar , Superoxide Dismutase/metabolism , Zinc Sulfate/pharmacologyABSTRACT
To investigate the effects of metallothionein (MT) on isolated rat heart, 16 Wistar rats were randomly divided into 2 groups. In control group (group C), distilled water was injected intraperitoneally and 24 h later isolated hearts were perfused with Langendorff and stored at 4℃ for 3 h with histidine-tryptophan-ketoglutarate (HTK) solutions, and then isolated hearts were perfused for 2 h by Langendorff. In experimental group (group E), 3.6% ZnSO4 was injected intraperitoneally, 24 h later isolated hearts were perfused by Langendorff and stored at 4℃ for 3 h with HTK solutions, and then the isolated herts were perfused for 2 h with Langendorff. MT content, the recovery of hemodynamics, myocardial water content (MWC), lactate dehydrogenase (LDH) and creatine kinase (CK) leakage, adenosine triphosphate (ATP) and malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, myocardial cell Ca2+ content, Ca2+-ATPase activity of mitochondria ([Ca2+-ATPase]m) and its Ca2+ content ([Ca2+]m), synthesizing ATP activity of mitochondria ([ATP]m), and the ultrastructure of cells were examined. There were a significant increase in group E in hemodynamic recovery, ATP content, SOD activity, [Ca2+-ATPase]m activity, [ATP]m activity, and substantial reduction in MWC, LDH and CK leakage, MDA content, myocardial cell Ca2+ content, [Ca2+]m content,and the ultrastructural injury were obviously milder than that of group C. This study demonstrated that MT has protective effects on isolated rat heart.
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To study the effects of different pH HEPES-KH reperfusate solution on immature myocardial protection, isolated perfused Langendorff model from immature rabbit hearts were developed formed. Control group (C) was perfused only with pH 7.4 HEPES-KH solution for 90 min. Ischemia/reperfusion group (group I/R) was perfused with pH 7.4 HEPES-KH solution before ischemia or after ischemia. Experimental group (group E), after ischemia, was perfused with pH 6.8, pH 7.1 and pH 7.4 HEPES-KH solutions for 5 min, 5 min, and 20 min, respectively. The left ventricular function recovery, MWC, LDH and CK leakage, MDA, ATP content, and SOD activity were determined. Our results showed that the left ventricular function recovery, ATP content and SOD activity in group E were higher than those of group I/R (P < 0.05). MWC, MDA content, LDH and CK leakage in group E were lower than those of group I/R (P < 0.05). These findings suggested that pH paradox might be one of important mechanisms for immature myocardial ischemia-reperfusion injury, and acidic perfusate, at the beginning of reperfusion, might attenuate pH paradox and ameliorate functional recovery in isolated perfused immature rabbit hearts.
Subject(s)
Myocardium/metabolism , Random Allocation , Superoxide Dismutase/metabolismABSTRACT
To study the effects of different pH HEPES-KH reperfusate solution on immature myocardial protection, isolated perfused Langendorff model from immature rabbit hearts were developed formed. Control group (C) was perfused only with pH 7.4 HEPES-KH solution for 90 min. Ischemia/reperfusion group (group I/R) was perfused with pH 7.4 HEPES-KH solution before ischemia or after ischemia. Experimental group (group E), after ischemia, was perfused with pH 6.8, pH 7.1 and pH 7.4 HEPES-KH solutions for 5 min, 5 min, and 20 min, respectively. The left ventricular function recovery, MWC, LDH and CK leakage, MDA, ATP content, and SOD activity were determined. Our results showed that the left ventricular function recovery, ATP content and SOD activity in group E were higher than those of group I/R (P < 0.05). MWC, MDA content, LDH and CK leakage in group E were lower than those of group I/R (P < 0.05). These findings suggested that pH paradox might be one of important mechanisms for immature myocardial ischemia-reperfusion injury, and acidic perfusate, at the beginning of reperfusion, might attenuate pH paradox and ameliorate functional recovery in isolated perfused immature rabbit hearts.