Dual role of polyamines in heart ischemia/reperfusion injury through regulation of mitochondrial permeability transition pore / 生理学报

Polyamines (putrescine, spermidine, and spermine) are essential polycations that play important roles in various physiological and pathophysiological processes in mammalian cells. The study was to investigate their role in cardioprotection against ischemia/reperfusion (I/R) injury and the underlying mechanism. Isolated hearts from male Sprague-Dawley rats were Langendorff-perfused and cardiac I/R was achieved by 30 min of global ischemia followed by 120 min of reperfusion. Different concentrations of polyamines (0.1, 1, 10, and 15 μmol/L of putrescine, spermidine, and spermine), cyclosporin A (0.2 μmol/L), or atractyloside (20 μmol/L) were given 10 min before the onset of reperfusion. The hemodynamics were monitored; the lactate dehydrogenase (LDH) levels in the coronary effluent were measured spectrophotometrically; infarct size was determined by the 2,3,5-triphenyltetrazolium chloride staining method; and mitochondrial permeability transition pore (MPTP) opening was determined spectrophotometrically by the Ca-induced swelling of isolated cardiac mitochondria. The results showed that compared to I/R alone, 0.1 and 1 μmol/L polyamines treatment improved heart function, reduced LDH release, decreased infarct size, and these effects were inhibited by atractyloside (MPTP activator). In isolated mitochondria from normal rats, 0.1 and 1 μmol/L polyamines treatment inhibited MPTP opening. However, 10 and 15 μmol/L polyamines treatment had the opposite effects, and these effects were inhibited by cyclosporin A (MPTP inhibitor). Our findings showed that polyamines may have either protective or damaging effects on hearts suffering from I/R by inhibiting or activating MPTP opening.

Isolation and multipotent differentiation of human decidua basalis-derived mesenchymal stem cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the biological features of human decidua basalis-derived mesenchymal stem cells (PDB-MSCs) in vitro and identify their capacity of multilineage differentiation.</p><p><b>METHODS</b>PDB-MSCs were harvested from the decidua basalis of term placental by enzymatic digestion and density gradient centrifugation, and the growth characteristics and morphological changes of the MSCs were observed by inverted microscope. The proliferative ability of the cells was assessed by Cell Counting Kit-8. The cell cycle and expressions of the surface markers (CD29, CD44, CD73, CD90, CD34, CD45, and CD14) of the MSCs were identified by flow cytometry. Multilineage differentiation capacity of the cells was tested by inducing their differentiation toward osteoblasts, adipocytes and chondroblasts in vitro.</p><p><b>RESULTS</b>MSCs isolated from human decidua basalis of term placental exhibited a morphology similar to that of bone marrow-derived MSCs, and grew into colonies in in vitro culture, where the cells proliferated rapidly after passage with a cell doubling time of 2.21∓0.21 days. More than 70% of the cells stayed in the resting stage (G(0)/G(1)) and showed positivity for CD29, CD44, CD73 and CD90, but not for CD14, CD34 or CD45. After induction, the cells showed positive results of alizarin red staining, oil red O staining and Alcian blue staining.</p><p><b>CONCLUSION</b>Human decidua basalis contains a rich source of MSCs, which can be easily isolated and cultured without affecting their capacity of multilineage differentiation. The PDB-MSCs may have the potential as a novel source of stem cells.</p>

Construction of a mouse pDsRed2-N1-SDF-1alpha eukaryotic expression vector and its expression in mouse bone marrow mesenchymal stem cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct the eukaryotic expression vector pDsRed2-N1-SDF-1alpha and observe its expression in the mouse bone marrow mesenchymal stem cells.</p><p><b>METHOD</b>SDF-1alpha gene sequence with XhoI, EcoRI restriction enzyme cutting site was amplified from the total RNA of mouse smooth muscle cells by reverse transcription-polymerase chain reaction (RT-PCR) and inserted into the eukaryotic expression vector pDsRed2-N1 encoding red fluorescent protein gene, and the insertion was verified by endonuclease digestion and DNA sequencing. Mouse bone marrow mesenchymal stem cells identified with immunofluorescence assay for vimentin expression were transfected with the constructed plasmid pDsRed2-N1-SDF-1alpha, and the expression of sdf-1alpha was detected using immunofluorescence assay.</p><p><b>RESULTS</b>The DNA fragment amplified by PCR from the total RNA was identical to SDF-1alpha from the gene library, and an identical DNA fragment was also amplified from the recombinants. Sequence analysis confirmed the successful insertion of SDF-1alpha into the pDsRed2-N1 vector and the eukaryotic expression vector pDsRed2-N1-SDF-1alpha was successfully constructed. The cultured mouse bone marrow mesenchymal stem cells positive for vimentin protein showed SDF-1alpha expression 24 h after transfection with the recombinant vector.</p><p><b>CONCLUSION</b>The pDsRed2-N1-SDF-1alpha eukaryotic expression vector constructed is capable of expression of SDF-1alpha fusion protein in the mouse bone marrow mesenchymal stem cells.</p>

Role of mitochondrial permeability transition pore in cardioprotection by remote preconditioning / 中国应用生理学杂志

<p><b>AIM</b>To investigate the role of mitochondrial permeability transition pore (MPTP) in the cardioprotection by remote preconditioning (RPC).</p><p><b>METHODS</b>Remote Precondition (RPC) was induced in anesthetized male Sprague-Dawley rats by three cycles of 5 min of right femoral artery occlusion followed by 5 min of reperfusion. Myocardial ischemia/reperfusion (I/R) injury was achieved by ligation of the left anterior descending coronary artery for 30 min and then reperfusion for 120 min. Infarct size was determined by 2,3,5-triphenyltetrazolium chloride (TTC) staining method. The level of lactate dehydragenase (LDH) in plasma and the opening of the mitochondrial permeability transition pore (MPTP) were measured.</p><p><b>RESULTS</b>RPC significantly decreased the infarct size and plasma lactate dehydrogenase level induced by I/R, and these effects were attenuated by atractyloside (Atr, 5 mg/kg), a MPTP activator. However, administration of cyclosporin A (CsA, 10 mg/kg), an inhibitor of MPTP, decreased the effect of I/R. In isolated ventricular myocytes loaded with calcein, RPC decreased the MPTP opening, and this effect was attenuated by Atr (20 micromol/L).</p><p><b>CONCLUSION</b>Inhibition of MPTP opening is involved in the cardioprotection by RPC.</p>

Mitochondrial calcium uniporter participates in remote preconditioning induced cardioprotection in rat hearts subjected to ischemia and reperfusion / 中国应用生理学杂志

<p><b>AIM</b>To investigate whether mitochondrial calcium uniporter participates in the cardioprotection of remote preconditioning in rat hearts subjected to ischemia and reperfusion in vivo.</p><p><b>METHODS</b>Rat hearts were subjected to 30 min regional ischemia (occlusion of left anterior descending artery) and 120 min reperfusion in vivo. Remote preconditioning was induced by three cycles of 5 min of right femoral artery occlusion followed by 5 min of reperfusion. The mean arterial blood pressure, heart rate, infarct size, and lactate dehydrogenase (LDH) activity in plasma during reperfusion were measured.</p><p><b>RESULTS</b>Remote preconditioning reduced both the infarct size and LDH release during reperfusion. Ruthenium red, an inhibitor of mitochondrial calcium uniporter, also decreased both the infarct size and LDH release. Administration of spermine, an activator of mitochondrial calcium uniporter, canceled the reduction of infarct size and LDH release induced by remote preconditioning.</p><p><b>CONCLUSION</b>These results indicate that remote preconditioning protects myocardium against ischemia and reperfusion injury, that effect may be related to inhibiting mitochondrial calcium uniporter opening.</p>

Combined application of virtual imaging techniques and three-dimensional computed tomographic angiography in diagnosing intracranial aneurysms / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The diagnostic value of virtual imaging combined with three-dimensional computed tomographic angiography (3D-CTA) for intracranial aneurysms has not been fully elucidated yet. This study aimed to evaluate the value of combined application of virtual imaging techniques and 3D-CTA in diagnosing patients with aneurismal subarachnoid hemorrhage (SAH) at the acute stage.</p><p><b>METHODS</b>Eighty patients with non-traumatic SAH received 3D-CTA examinations. The raw CT data of these patients were reconstructed and transferred into the 3D mode through the surgical plan system based on virtual reality (VR) image, and the 3D virtual images of skulls and brain blood vessels were acquired. The location, size and shape of aneurysms and their anatomic relationship with adjacent tissues were measured from many points of view.</p><p><b>RESULTS</b>Seventy-three aneurysms were detected in 68 of the 80 patients, but 2 aneurysms were detected in 2 of the 5 patients who had been found free of aneurysms previously and had received 3D-CTA examinations for a second time one month later. The 3D virtual images produced by the virtual imaging system were clear and vivid, and they could reveal the location and size of the aneurysm and its relations to the parent artery and skull directly.</p><p><b>CONCLUSIONS</b>The imaging of 3D-CTA is convenient, reliable and fast in diagnosing intracranial aneurysms and can be regarded as the first choice for the diagnosis and treatment of ruptured intracranial aneurysms. Combined with the surgical plan system based on the VR image, 3D-CTA may obtain more imaging information about aneurysms.</p>

Correlation between power Doppler vascularity index and microvessel density in high-grade gliomas and adjacent edema / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the correlation between power Doppler vascularity index (PDVI) and microvessel density (MVD) and evaluate the angiogenesis in high-grade gliomas and the adjacent edema in patients with glioma using intraoperative power Doppler ultrasound (PDUS) during gross total resection.</p><p><b>METHODS</b>In 25 cases of high-grade gliomas undergoing gross total tumor resections, PDUS was performed intraoperatively and the regions of interest within the tumor and the adjacent edema were analyzed with Photoshop software to measure the tumoral and peritumoral blood flow quantified as PDVI. The tumoral and adjacent MVD were determined using immunohistochemical staining for CD34. The correlation between PDVI in the gliomas and the adjacent edema and MVD in the corresponding areas were analyzed using Spearman correlation test.</p><p><b>RESULTS</b>The measurement of both PVDI and MVD revealed significant difference in vascularity between the gliomas and the adjacent edema (t=0.000, P<0.01), and PDVI was positively correlated to MVD measurement (r=0.7248 in the tumors and r=0.6608 in the adjacent edema).</p><p><b>CONCLUSIONS</b>The difference in the vascularity between the tumor and adjacent edema allows their distinction by PDUS during operation for high-grade glioma. Intraoperative PDUS provides an accurate and reliable means for measuring vascularity in the glioma and the adjacent edema tissue.</p>

Mitochondrial calcium uniporter participates in TNF-alpha induced cardioprotection in isolated rat hearts subjected to ischemia/reperfusion / 中国应用生理学杂志

<p><b>AIM</b>To investigate whether mitochondrial calcium uniporter participates in the cardioprotection of tumor necrosis factor alpha (TNFalpha) pretreatment in isolated rat hearts subjected to ischemia/reperfusion.</p><p><b>METHODS</b>Isolated perfused rat hearts were subjected to 30 min regional ischemia (occlusion of left anterior descending artery) and 120 min reperfusion. The infarct size, coronary flow (CF) and lactate dehydrogenase (LDH) release during reperfusion were measured. The mitochondria of the heart were isolated and suspended in the swelling buffer for measurement of absorbance at 520 nm.</p><p><b>RESULTS</b>Pretreatment with TNFa at 10 U/ml for 7 min followed by 10 min washout reduced the infarct size and LDH release, and improved the recovery of CF during reperfusion. Administration of spermine (20 micromol/L), an opener of mitochondrial calcium uniporter, for 10 min during early reperfusion attenuated the reduction of infarct size and LDH release, and improvement of CF induced by TNFalpha. In isolated mitochondria of the heart pretreated with TNFalpha, the absorbance at 520 nm decreased less than that of mitochondria without TNFalpha pretreatment. Administration of spermine (50 micromol/L) attenuated the change of the absorbance induced by TNFalpha.</p><p><b>CONCLUSION</b>The findings indicate that TNFalpha protects myocardium against ischemia/reperfusion injury via inhibiting mitochondrial calcium uniporter opening as well as mitochondrial permeability transition pore opening.</p>

Role of mitochondrial calcium uniporter in myocardial hypoxia/reoxygenation induced injury / 中国应用生理学杂志

<p><b>AIM</b>To investigate the role and mechanism of mitochondrial calcium uniporter (MCU) in myocardial hypoxia/reoxygenation injury.</p><p><b>METHODS</b>Isolated rat hearts were perfused with Langendorff apparatus. The hypoxia/reoxygenation injury was achieved by ligation of left anterior coronary artery for 30 min followed by release of ligation for 120 min. The left ventricular developed pressure (LVDP), the maximum rise/fall rate of left ventricular pressure (+/- dP/dt(max)), and the left ventricular end-diastolic pressure (LVEDP) were recorded. Activities of lactate dehydrogenase (LDH) in coronary effluent and reactive oxygen species (ROS) of myocardial mitochondria were spectrophotometrically assayed. Infarct size was determined by TTC staining method.</p><p><b>RESULTS</b>Compared with the hypoxia/reoxygenation (H/R) group, ruthenium red (RR, 5 micromol/L), given at the on set of reoxygenation, significantly improved the contractile function of left ventricle, decreased the myocardial infarct size, alleviated the production of ROS in myocardial mitochondria and LDH release in coronary effluent. Spermine (20 micromol/L), given at the onset of reoxygenation, enhanced the production of ROS in the mitochondria and LDH release in coronary effluent at 5, 20 and 30 min of reoxygenation, however, there were no significant differences of ventricular contractile parameters and infarct size between groups subjected to hypoxia/reoxygenation with or without spermine treatment. Co-treatment of ROS scavenger N-2-mercaptopropionyl glycine (1 mmol/L) with spermine abolished the effect of spermine.</p><p><b>CONCLUSION</b>Inhibition of mitochondrial calcium uniporter may refrain heart from hypoxia/reoxygenation injury via decreasing the production of ROS in heart mitochondria.</p>