Combination of hyaluronic acid and bone marrow mesenchymal stem cells promotes cardiac function after myocardial infarction / 中国组织工程研究

BACKGROUND: The poor retention and survival of donor cells implanted into the myocardium limit the efficacy of cell therapy for myocardial infarction. Embedding cells in natural or synthetic biomaterials is a strategy to address this issue. OBJECTIVE: To explore the effects of bone marrow mesenchymal stem cells (BMSCs) encapsulated in hyaluronic acid (HA) hydrogel on cardiac function after myocardial infarction. METHODS:BMSCs from male Sprague-Dawley rats were isolated and cultured,and then HA-encapsulated BMSCs were cultured in vitro in the three-dimensional manner. A model of myocardial infarction was made by cutting the anterior descending artery of female Sprague-Dawley rats. After 1 week, the model rats were screened by ultrasonic testing and then eligible ones were randomly divided into four groups: PBS group (n=8), HA group (n=8), BMSCs group (n=29), and HA-encapsulated BMSCs group (n=29). At 1 week after modeling, the model rats underwent the secondary thoracotomy and the implants were injected into the marginal zone and infarcted region in corresponding groups. The survival rate and apoptosis of implanted cells were examined at post-injection day 1, week 1 and week 2 by RT-PCR and TUNEL respectively. At post-injection week 4, changes of cardiac microstructure and function were evaluated by histological examination and echocardiography. RESULTS AND CONCLUSION: Compared with the BMSCs group, HA hydrogel significantly enhanced the survival rate and reduced the apoptotic rate of BMSCs at post-injection day 1 and week 2 (both P < 0.05). At post-injection week 4, the HA+BMSCs combined treatment yielded the best recovery of cardiac function (P < 0.05). To conclude, HA hydrogel can act as a vehicle for BMSCs delivery and improve the beneficial effects of implanted BMSCs in early myocardial repair(within 2 weeks after infarction)via enhancing cell retention and survival.

Effect of tannic acid treatment on the physico-chemical properties of glutaraldehyde-fixed bovine jugular vein / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the effects of tannic acid (TA) treatment on the physico-chemical properties of glutaraldehyde (Glut)-fixed bovine jugular vein (BJV).</p><p><b>METHODS</b>Fresh BJVs were treated with Glut or Glut/TA, respectively. The shrinkage temperature, resistance to collagenase or elastase digestion, bio-mechanical properties, and molecular structure of these prepared BJVs were evaluated by Fourier transform infrared spectroscopy.</p><p><b>RESULTS</b>TA treatment resulted in higher shrinkage temperature (P < 0.01), higher resistance to collagenase or elastase digestion (P < 0.01), slightly increased tensile strength (P < 0.01), and elongation at break (P < 0.05) in Glut/TA BJV walls when compared with those of Glut group. Chemical bonds existed between TA and JBV tissue.</p><p><b>CONCLUSION</b>TA treatment can effectively improve the physicochemical properties of Glut-fixed BJVs.</p>

Mitigated calcification of glutaraldehyde-fixed bovine pericardium by tannic acid in rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Bioprosthetic heart valves derived from glutaraldehyde (Glut)-fixed xenografts have been widely used to replace diseased cardiac valves. However, calcification and degeneration are common following their implantation. Inflammation is closely associated with calcification of Glut-fixed xenografts via macrophage infiltration. Tannic acid (TA) possesses anti-inflammatory effects. This study was designed to investigate the anti-calcification of TA treatment on the Glut-fixed bovine pericardium (BP) in a rat subdermal model.</p><p><b>METHODS</b>Fresh BP was divided into two groups (10 in each group) and separately subjected to different fixation procedures as follows: (1) Glut group: fixation with 0.6% Glut alone; (2) Glut/TA group: fixation with 0.6% Glut and subsequent 0.3% TA. Then the BP samples were subdermally implanted in juvenile male Sprague-Dawley rats and explanted 21 days after implantation. Each explanted BP sample was divided into three parts for calcium content analysis, von Kossa's staining and immunohistochemical staining, and reverse transcription-polymerase chain reaction study.</p><p><b>RESULTS</b>The data from quantitative calcium analysis and von Kossa's staining showed that Glut-fixed BP developed significantly more calcification than Glut/TA-fixed BP ((90.3 +/- 32.5) mg/g dry weight vs (6.4 +/- 1.3) mg/g dry tissue, P < 0.01). Immunostaining demonstrated lower matrix metalloproteinase-9 and tenascin-C expression as well as macrophage infiltration into Glut/TA-fixed BP than in its Glut-fixed counterpart (P < 0.01 for all). Additionally, the reverse transcription-polymerase chain reaction study showed that higher levels of expression of matrix metalloproteinase-9 and tenascin-C mRNA occurred within Glut-fixed BP than within the Glut/TA-fixed ones (P < 0.01 for all).</p><p><b>CONCLUSION</b>TA exerts excellent anti-calcification effects on Glut-fixed BP via inhibiting macrophage infiltration and expression of matrix metalloproteinase-9 and tenascin-C.</p>

Hemocompatibility of bovine pericardium with additional sodium bisulfite treatment / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the hemocompatibility of glutaraldehyde (GA)-tanned bovine pericardium additionally treated by sodium bisulfite (SOB) solution.</p><p><b>METHODS</b>The hemocompatibility of GA-tanned bovine pericardium treated by SOB solution is evaluated by using dynamic clotting time test, blood platelet adhension test, D-dimeride determination, and complement activation test. The GA-tanned bovine pericardium was used as control.</p><p><b>RESULTS</b>The curve of absorbance-clotting time of two kinds of bovine pericardium was similar in dynamic clotting time test. There was no significant difference between SOB-treated and control groups in blood platelet adhension test. The D-dimeride contents of all bioprostheses were at normal level, and the D-dimeride content of GA-tanned bovine pericardium treated by SOB solution was significantly lower than that of control group (P < 0.05). In complement activation test, the level of complement C3a in SOB-treated group was significantly lower than that in control group (P < 0.05).</p><p><b>CONCLUSION</b>GA-tanned bovine pericardium treated by SOB solution meets the demands of cardiac interstitial implanted materials in hemocompatibility.</p>

Crosslinking bovine pericardial bioprosthetic heart valves by phthalocyanine sensitized photooxidation reaction / 中国医学科学院学报

<p><b>OBJECTIVE</b>To crosslink bovine pericardial valves by phthalocyanine sensitized photooxidation reaction.</p><p><b>METHODS</b>Fresh bovine pericardial tissues were immersed in PBS solution containing 0.01% cupreous sulfonatophthalocyanine and exposed to a broad wavelength light source for 20-120 h. Using sodium dodecyl sulfate-polyarylamide gel electrophoresis (SDS-PAGE) to analyze the cross-linking extent of pericardial tissue. With the help of attenuated total reflection-fourier transform infrared (ATR-FTIR), explained the change of protein structure after photooxidation reaction. Differential scanning calorimetry (DSC) was used to measure the change of shrinkage temperature. Tissue water content experiment method was also used.</p><p><b>RESULTS</b>Photooxidized tissue was resistant to extraction when it was compared with untreated tissue and had similar crosslinking extent over glutaraldehyde-treated tissue. The three dimension structure of collagen were changed but not seriously destroyed and the model of photooxidation reaction was validated. Phthalocyanine-treated tissue was much more flexible than glutaraldehyde-treated tissue.</p><p><b>CONCLUSION</b>Bovine pericardial tissue can be successfully crosslinked by phthalocyanine-mediated photooxidation reaction.</p>

Using chemical methods to crosslink xenogeneic heart valves: the progress of bioprosthetic heart valves / 中国医学科学院学报

Glutaraldehyde clinically is the most commonly accepted crosslinking reagent for bioprosthetic valves preparation. Glutaraldehyde-treated tissue is stable against chemical and enzymatic degradation; however, its calcification and cytotoxicity are severe. Dye-mediated photooxidation is an alternative tissue preservation method that oxidizes the protein with visible light in the presence of a suitable photosensitizer. This article reviews chemical mechanism, research progress, clinical applications future development of these two methods.