[Effect of a novel injectable hydrogel implant on ventricular remodeling in rabbits with experimental myocardial infarction].

OBJECTIVE: To observe whether injectable hydrogel implantation could prevent adverse cardiac remodeling and preserve cardiac function in rabbits with myocardial infarction (MI). METHODS: A novel injectable hydrogel, the copolymer MPM/alpha-CD, which self-assembled between alpha-cyclodextrin and methoxy polyethylene glycol-poly (caprolactone)-(dodecanedioic acid)-poly (caprolactone)-methoxypolyethylene glycol triblock polymer, was synthesized by chemical crosslinking and characterized by biocompatibility and biodegradability. Experimental MI was induced in male rabbits by coronary artery ligation. The MI rabbits were randomly divided into hydrogel group (200 microl MPM/alpha-CD were injected into the infarcted myocardium 7 days after MI) and control group (equal volume phosphate buffered saline myocardial injection, n = 8 each). Four weeks after MPM/alpha-CD implantation, echocardiography, histochemistry and immunohistochemistry were performed. RESULTS: Left ventricle ejection fraction was significantly improved in the hydrogel-treated group (56.1% +/- 8.4%) than that in the control group (37.3% +/- 6.4%, P < 0.05). Histological analysis indicated that hydrogel degraded 4 weeks after hydrogel injection, and prevented scar expansion and wall thinning [(3.08 +/- 0.32) mm vs. (2.18 +/- 0.46) mm in control group, P < 0.05]. Neovasculature formation was similar between the hydrogel group [(100.8 +/- 2.4)/mm(2)] and the control [(98.5 +/- 2.9)/mm(2), P > 0.05]. CONCLUSION: MPM/alpha-CD could serve as an excellent injectable biomaterial for improves cardiac function and attenuating scar expansion and left ventricular dilation in MI rabbits.

Novel thermosensitive hydrogel injection inhibits post-infarct ventricle remodelling.

AIMS: Myocardial infarction (MI) remains the commonest cause of cardiac-related death throughout the world. Adverse cardiac remodelling and progressive heart failure after MI are associated with excessive and continuous damage of the extracellular matrix (ECM). In this study, we hypothesized that implantation of hydrogel into infarcted myocardium could replace the damaged ECM, thicken the infarcted wall, and inhibit cardiac remodelling. METHODS AND RESULTS: MI was induced in rabbits by coronary artery ligation; 4 days later, 200 microL Dex-PCL-HEMA/PNIPAAm gel solution was injected into the infarcted myocardium. Injection of phosphate-buffered saline served as control. Thirty days after treatment, histological analysis indicated that injection of the biomaterial prevented scar expansion and wall thinning compared with controls. Echocardiography studies showed that injection of hydrogel increased left ventricular ejection fraction and attenuated left ventricular systolic and diastolic dilatation. Haemodynamic analysis demonstrated improved cardiac function following implantation of the hydrogel. CONCLUSION: These results suggest that injection of thermosensitive Dex-PCL-HEMA/PNIPAAm hydrogel is an effective strategy that prevents adverse cardiac remodelling and dysfunction in MI rabbits.

A strategy for precise and large scale identification of core fucosylated glycoproteins.

Core fucosylation (CF) patterns of some glycoproteins are more sensitive and specific than evaluation of their total respective protein levels for diagnosis of many diseases, such as cancers. Global profiling and quantitative characterization of CF glycoproteins may reveal potent biomarkers for clinical applications. However, current techniques are unable to reveal CF glycoproteins precisely on a large scale. Here we developed a robust strategy that integrates molecular weight cutoff, neutral loss-dependent MS(3), database-independent candidate spectrum filtering, and optimization to effectively identify CF glycoproteins. The rationale for spectrum treatment was innovatively based on computation of the mass distribution in spectra of CF glycopeptides. The efficacy of this strategy was demonstrated by implementation for plasma from healthy subjects and subjects with hepatocellular carcinoma. Over 100 CF glycoproteins and CF sites were identified, and over 10,000 mass spectra of CF glycopeptide were found. The scale of identification results indicates great progress for finding biomarkers with a particular and attractive prospect, and the candidate spectra will be a useful resource for the improvement of database searching methods for glycopeptides.

Injection of a novel synthetic hydrogel preserves left ventricle function after myocardial infarction.

Myocardial infarction (MI) and the subsequent heart failure remain one of the leading causes of morbidity and mortality world wide. A number of studies have demonstrated that bioderived materials improve cardiac function after implantation because of their angiogenic potential. In this study, we hypothesized that injection of biomaterials into infarcted myocardium can preserve left ventricular (LV) function through its prevention of paradoxical systolic bulging. To test this hypothesis, infarction was induced in rabbit myocardium by coronary artery ligation. After 1 week, 200-microL alpha-cyclodextrin (alpha-CD)/MPEG-PCL-MPEG hydrogel was injected into the infarcted myocardium. Injection of phosphate buffered saline (PBS) served as controls. Twenty-eight days after the treatment, histological analysis indicated that the injection of hydrogel prevented scar expansion and wall thinning compared with the control (p < 0.05) without more microvessel density in infarcted myocardium (p = 0.70). LV ejection fraction, determined by echocardiography, was significantly greater in the hydrogel-treated group (56.09% +/- 8.42%) than the control group (37.26% +/- 6.36%, p = 0.001). The LV end-diastolic and end-systolic diameters were 2.07 +/- 0.33 cm and 1.74 +/- 0.30 cm, respectively, in the control group. Smaller LV end-diastolic diameter (1.61 +/- 0.26 cm, p = 0.005) and smaller end-systolic diameter (1.17 +/- 0.23 cm, p = 0.001) were found in the hydrogel-treated group. These results suggest that alpha-CD/MPEG-PCL-MPEG hydrogel could serve as an injectable biomaterial that prevents LV remodeling and dilation for the treatment of MI.

Low intensity ultrasound-induced apoptosis in human gastric carcinoma cells.

AIM: To investigate the low intensity ultrasound (US)-induced apoptosis in human gastric carcinoma cells and its potential mechanism and to suggest a new therapeutic approach to gastric carcinoma. METHODS: Human SGC-7901 gastric carcinoma cells were cultured in vitro and irradiated by low intensity US for 10 min at different intensities with different incubation times after irradiation. Morphologic changes were examined under microscope with trypan blue staining and then the percentage of early apoptotic cells was detected by flow cytometry (FCM) with double staining of fluorescein isothiocyanate (FITC)-Annexin V/propidium iodide (PI). Two-dimensional electrophoresis (2DE) was used to get the protein profile and some proteins differently expressed after US irradiation were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Functional analysis was performed to investigate the mechanism of US-induced cell apoptosis. RESULTS: The percentage of apoptotic cells increased about 10% after US irradiation (12.0 W/cm(2), 12 h culture). The percentage of early apoptosis and secondary necrosis in the US-irradiated cells increased with the increased US intensity. Moreover, apoptotic cells increased with the increased culture time after US irradiation and reached its maximum at about 12 h. Several new proteins appeared after US irradiation and were up or down regulated more than 2 times. Some heat shock proteins (HSPs) were found to be associated with the signal process simulating the apoptosis of cells. CONCLUSION: Low intensity US could induce apoptosis in human gastric carcinoma cells. US-induced apoptosis is related to US intensity/culture time. US-induced apoptosis may be caspases-dependent and endoplasmic reticulum (ER) stress-triggered apoptosis may also contribute to it. Proteomic experimental system is useful in finding the protein alteration in carcinoma cells after US irradiation, helping to develop a new cancer therapy.

Protein profile of human hepatocarcinoma cell line SMMC-7721: identification and functional analysis.

AIM: To investigate the protein profile of human hepatocarcinoma cell line SMMC-7721, to analyze the specific functions of abundant expressed proteins in the processes of hepatocarcinoma genesis, growth and metastasis, to identify the hepatocarcinoma-specific biomarkers for the early prediction in diagnosis, and to explore the new drug targets for liver cancer therapy. METHODS: Total proteins from human hepatocarcinoma cell line SMMC-7721 were separated by two-dimensional electrophoresis (2DE). The silver-stained gel was analyzed by 2DE software Image Master 2D Elite. Interesting protein spots were identified by peptide mass fingerprinting based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and database searching. RESULTS: We obtained protein profile of human hepatocarcinoma cell line SMMC-7721. Among the twenty-one successfully identified proteins, mitofilin, endoplasmic reticulum protein ERp29, ubiquinol-cytochrome C reductase complex core protein I, peroxisomal enoyl CoA hydratase, peroxiredoxin-4 and probable 3-oxoacid CoA transferase 1 precursor were the six novel proteins identified in human hepatocarcinoma cells or tissues. Specific functions of the identified heat-shock proteins were analyzed in detail, and the results suggested that these proteins might promote tumorigenesis via inhibiting cell death induced by several cancer-related stresses or via inhibiting apoptosis at multiple points in the apoptotic signal pathway. Other identified chaperones and cancer-related proteins were also analyzed. CONCLUSION: Based on the protein profile of SMMC-7721 cells, functional analysis suggests that the identified chaperones and cancer-related proteins have their own pathways to contribute to the tumorigenesis, tumor growth and metastasis of liver cancer. Furthermore, proteomic analysis is indicated to be feasible in the cancer study.

[Experimental study of replacement of an esophageal segment with an nitinol alloy composite artificial esophagus].

OBJECTIVE: To observe the feasibility of a segment thoracic esophagus replaced by using a nitinol alloy composite artificial esophagus. METHODS: A nitinol alloy composite artificial esophagus was made of a nitinol tube coated with a silicone membrane with a dacron flange 1 cm proximal to each end. There were ten pigs for the models of experimental animal. The models of experimental animal were established by excised a segment of 7 cm long thoracic esophagus and replaced with the graft. In accordance with the different anastomosis connective way 10 pigs were divided into group I and group II, every group had 5 pigs. In group I monolayer end-to-end anastomosis was used with this prosthesis. In group II monolayer end-to-end anastomosis was used with this prosthesis and above the site of anastomosis adding dacron strip fixed. After operation the operate animals were observed for eating and health. Esophagography and flexible esophagoscopy were performed once a month at the first, second, and third postoperatively month. Three pigs of the grafted prostheses sloughed out spontaneously at different postoperatively period were killed for autopsy and pathologic examination of the neoesophagus. RESULTS: All pigs had no leakage at the site of anastomosis and survived over 6 months. The longest survival was 20 months. Seven of 10 pigs the grafted prostheses sloughed out spontaneously at 2 to 6 months after the operation (4 in group I and 3 in group II). The grafted prostheses sloughed out spontaneously less than 3 months after operation, marked neoesophageal stenosis in the grafted portion was recognized (3 in group I). They displayed serious difficulty in eating. But the prostheses sloughed out spontaneously more than 3 months after operation, neoesophageal stenosis was increased slightly and the stenosis was only temporary and gradually resolved. (1 in group I, 3 in group II) They lived in good health and without difficulty in eating. Three of 10 pigs the grafted prosthesis still stayed in the grafted place over 10 months (1 in group I, 2 in group II). The neoesophageal had no stenosis. They were perfectly well in eating. CONCLUSIONS: A segment excised pig esophagus replaced with a nitinol alloy composite artificial esophagus is feasible and takes a better result.