Specific determination of endothelial cell viability in the whole cell fraction from cryopreserved canine femoral veins using flow cytometry

Survival rates of patients with malignant melanoma of the skin

This paper reports on cases of malignant melanoma of the skin diagnosed in Finland between 1963 and 1968. Sufficient data for estimating the survival was obtained in 691 cases. The ten-year relative survival rate for the entire series was 41% for males and 53% for females. This sex difference remained constant throughout the various divisions of the material. The ten-year relative survival rate of males with tumour in stage I was 52% and that of females 59%. The highest survival rate of stage I tumour in males was for the tumours of the lower extremities (77%) and in females for those in the head and neck (79%). The relative survival of patients with tumour of the trunk in stage I was lowest in both sexes (males 49%, females 45%). The ten-year relative survival rate of patients with a local recurrence was 33% in males and 27% in females. The relative ten-year survival rates of patients with superficial melanoma were 130% in males and 92% in females.

Prevention of reactive oxygen species-induced oxidative stress in human microvascular endothelial cells by green tea polyphenol

The potential protective roles played by green tea polyphenol (GTP) against the injurious effects of reactive oxygen species in human microvascular endothelial cells (HUMVECs) were investigated. Oxidative stress was induced in cultured HUMVECs, either by adding 10 mM H2O2 or by the action of 10 U/l xanthine oxidase (XO) in the presence of xanthine (250 microM). Both treatments produced a significant reduction (to 68% and 71%, respectively) in HUMVEC viability, as assessed by fluorescence double staining method followed by flow cytometric analysis. On the microscopic observations, the morphological changes and necrotic detachment were appreciably induced by both treatments. The H2O2-induced alterations were completely prevented by pre-incubating the ECs with 10 microg/ml GTP for 1 h. When the oxidative stress was induced by XO, the cell viability and morphology were also significantly maintained at the same GTP concentration. These results demonstrate that GTP can act as a biological antioxidant in a cell culture experimental model and prevent oxidative stress-induced cytotoxicity in ECs.

The use of temperature-composition combinatorial libraries to study the effects of biodegradable polymer blend surfaces on vascular cells

Controlling cellular and physiological responses such as adhesion, proliferation and migration is a highly desirable feature of engineered scaffolds. One important application would be the design of tissue engineered vascular grafts that regulate cell adhesion and growth. We utilized temperature-composition combinatorial polymer libraries to investigate the effects of surfaces of blended poly(D,L-lactic-co-glycolic acid) (PLGA) and poly(epsilon-caprolactone) (PCL) on murine vascular smooth muscle cells (SMC). In this manner, SMCs were exposed to approximately 1000 distinguishable surfaces in a single experiment, allowing the discovery of optimal polymer compositions and processing conditions. SMC adhesion, aggregation, proliferation, and protein production were highest in regions with mid- to high-PCL concentrations and high annealing temperatures. These regions exhibited increased surface roughness, increased microscale PLGA-rich matrix stiffness, and significant change of bulk PCL-rich crystallinity relative to other library regions. This study revealed a previously unknown processing temperature and blending composition for two well-known polymers that optimized SMC interactions.

The effect of scaffold degradation rate on three-dimensional cell growth and angiogenesis

Even though degradation products of biodegradable polymers are known to be largely non-cytotoxic, little detailed information is available regarding the degradation rate-dependent acidic byproduct effect of the scaffold. In vitro and in vivo scaffold degradation rate could be differentiated using a fast degrading polymer (e.g., poly D, L-lactic-glycolic acid co-polymer, PLGA, 50:50) and a slow degrading polymer (e.g., poly epsilon-caprolactone, PCL). We applied a new method to develop uniform 10 microm thickness of high porous scaffolds using a computer-controlled knife coater with a motion stage and exploiting phase transition properties of a combination of salts and water in salt-leaching method. We then verified in vitro the effect of fast degradation by assessing the viability of primary mouse aortic smooth muscle cell cultured in the three-dimensional scaffolds. We found that cell viability was inversely related to degradation rate and was dependent on the depth from the seeding (upper) surface toward the lower surface. The pH measurement of culture medium using fluorescence probes showed time-dependent decrease in pH in the PLGA scaffolds, corresponding to PLGA degradation, and closely related to cell viability. In vivo analysis of scaffolds implanted subcutaneously into the back of mice, showed significant differences in inflammation and cell invasion into PLGA vs. PCL. Importantly, these were correlated with the degree of the functional angiogenesis within the scaffolds. Again, PLGA scaffolds demonstrated less cell mobilization and less angiogenesis, further supporting the negative effect of the acidic environment created by the degradation of biocompatible polymers.

Effects of green tea polyphenol on preservation of human saphenous vein

The potential role of green tea polyphenol (GtPP) in preserving the human saphenous vein was investigated under physiological conditions. The vein segments were incubated for 1, 3, 5, 7 and 14 days, either after 4h of treatment with 1.0mg/ml GtPP or in the presence of GtPP at the same concentration. After incubation, the endothelial cell viability, endothelial nitric oxide synthase (eNOS) expression and the vein histology were evaluated. When the veins were not treated with GtPP, the viability of the endothelial cells was significantly reduced with the progress in the culture time, and none of the cells expressed eNOS after 5 days. Furthermore, severe histological changes and structural damage were observed in the non-treated veins. In contrast, incubating the veins after 4h of GtPP treatment significantly prevented these phenomena. The cellular viability of the GtPP-treated vein was approximately 64% after 7 days, and eNOS expression was maintained up to 40%, compared to that of the fresh vein. The histological observations showed that the vasculature was quite similar to that of the fresh vein. When incubated with GtPP, the vein could also be preserved for 1 week under physiological conditions retaining both its cellular viability (61%) and eNOS expression level (45%) and maintaining its venous structure without any morphological changes. These results demonstrate that GtPP treatment may be a useful method for preserving the HSV.

Inhibitory effect of antisense vascular endothelial growth factor 165 eukaryotic expression vector on proliferation of hepatocellular carcinoma cells

AIM: To construct antisense VEGF₁₆₅ eukaryotic expression vector PCDNA₃-as-VEGF₁₆₅ and to study its expression and effect on the proliferation of hepatocarcinoma SMMC-7721 cells.

METHODS: VEGF₁₆₅ cDNA was inserted into polylinker sites of eukaryotic expression vector PCDNA₃ to construct PCDNA₃-as-VEGF₁₆₅. Then the vector was transferred into human hepatocarcinoma cell strain SMMC-7721 with cation lipofectamine 2000 mediated methods to evaluate the expression of VEGF protein and the inhibitory effect on the proliferation of hepatocarcinoma SMMC-7721 cells.

RESULTS: The detection indicated the presence of VEGF cDNA in normally cultured SMMC-7721 cells by PCR. VEGF mRNA expression was notably decreased in SMMC-7721 cells by RT-PCR after PCDNA₃-as-VEGF₁₆₅ transfection. The expression of VEGF protein was dramatically inhibited (142.01 ± 7.95 vs 1 625.52 ± 64.46 pg·ml^-1, P < 0.01) 2 days after transfection, which correlated with the dose of PCDNA₃-as-VEGF₁₆₅ gene. VEGF protein was most expressed in PCDNA₃ transferred SMMC-7721 cells but few in PCDNA₃-as-VEGF₁₆₅ transferred cells by immunohistochemical staining. The apoptotic rate of hepatocarcinoma SMMC-7721 cells was significantly promoted (17.98% ± 0.86% vs 4.86% ± 0.27%, P < 0.01) and the survival rate was notably decreased (80.99% ± 3.20% vs 93.52% ± 3.93%, P < 0.05) due to antisense VEGF₁₆₅ by flow cytometry (FCM). The transfection of antisense VEGF₁₆₅ gene resulted in the inhibitory effect on the proliferation of hepatocarcinoma cells by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and the death of all hepatocarcinoma cells on day 6 after transfection.

CONCLUSION: It is confirmed that antisense VEGF₁₆₅ can inhibit the expression of VEGF protein, interfere with the proliferation and induce the apoptosis of hepatocarcinoma cells in our study. Antisense VEGF₁₆₅ gene therapy may play an important role in the treatment of human hepatocarcinoma.

Abdominal aorta transplantation after programmed cryopreservation

AIM: To study the morphologic and cellular immunologic changes after homologous transplantation of the abdominal aorta in rats after programmed cryopreservation (-196 °C).

METHODS: Abdominal aorta was harvested from anesthetized Spraque Dawley (SD) rats for cryopreservation (group B) or immediate implantation (group A). The survival rates and apoptotic rates of aortic endothelial cells (ECs) were examined. The patency rates, histology and cellular immunologic changes of the abdominal aorta were examined on days 1, 3, 7, 14, 30, 60 after transplantation respectively.

RESULTS: The survival rate of ECs after programmed cryopreservation was 90.1% ± 1.79%, about 3.4% lower than that of uncryopreservation (93.5% ± 1.96%). The apoptotic rates of ECs was increased after cryopreservation (7.15% vs 4.86%, P < 0.05). The patency rate of group B was significantly higher than that of group A (91.6% ± 12.9% vs 62.5% ± 26.2%, P < 0.01). CD4/CD8 ratio, TCR αβ and CD11b/ CD18 ratio of group B were significantly lower than those of group A (P < 0.05). Revivification of the cryopreserved abdominal aorta showed normal adventitia and intact smooth muscle cells.

CONCLUSION: Cryopreservation can reduce homologous abdominal aortic antigenecity. Even if without administration of immunosuppressive agents, it is still feasible to implement homologous artery grafting in rats.

Preservation of Human Saphenous Vein against Reactive Oxygen Species-induced Oxidative Stress by Green Tea Polyphenol Pretreatment

The injurious effects of reactive oxygen species on venous tissues and the potential protective role played by green tea polyphenol (GTPP) on human saphenous veins were investigated. Oxidative stress was induced exogenously in the vein segments, either by adding 0.8 or 1.6 M of H2O2, or by using 80 or 160 U/L of xanthine oxidase in the presence of xanthine (0.5 mM). After incubation, the viability of the endothelial cells dissociated from veins and the histology of the veins were evaluated. Due to both types of treatment, a significant decrease in cellular viability, severe morphological changes in the veins, and extracellular structural damage were induced. The H2O2-induced alterations were prevented by preincubating the veins with either 0.5 or 1.0 mg/ml of GTPP for 1 h. When the oxidative stress was induced by xanthine oxidase, cellular viability and venous structure were preserved at the same polyphenol concentrations. These results demonstrate that GTPP can act as a biological antioxidant and protect veins from oxidative stress-induced toxicity.

Liposomal entrapment of cefoxitin to improve cellular viability and function in human saphenous veins

Liposomal cefoxitin was prepared and applied to the pretreatment of human saphenous vein (HSV) for implantation. The possible use of liposomal cefoxitin to improve cellular viability and function and to maintain its potential sterilization effect was investigated. Entrapment efficiency and size distribution of liposomal cefoxitin were 75.7% and 652 +/- 75.7 nm, respectively. The weight ratio between cefoxitin and liposome was calculated at 1 : 40.6. When cefoxitin was entrapped with liposome, the released amount of cefoxitin was not affected by temperature conditions (37 degrees C, 25 degrees C, and 4 degrees C). The amount of free cefoxitin present in HSV reached 59% at 0.5 h and gradually decreased with time, while liposomal cefoxitin showed a maximum amount (63%) at 1.5 h, indicating that liposomal cefoxitin seemed to control the initial amount of cefoxitin present in HSV. Liposomal cefoxitin showed better viabilities of whole cells and endothelial cells dissociated from HSV than free cefoxitin and remarkably superior function of endothelial cells, as determined by Griffonia simplicifolia agglutinins-fluorescein isothiocyanate/propidium iodide double-staining methods combined with flow cytometry and endothelial nitric oxide synthase assay, respectively. In terms of sterilization effect, there was no significant difference between liposomal cefoxitin and free cefoxitin. These results suggest that liposomal entrapment of cefoxitin could improve cellular viability and functions and maintain the original sterilization effect.

Antibacterial effect of antibiotic solution on cellular viability in canine veins

Pretreatment of tissue by using antibiotics is a critical step to prevent microbial contamination before venous transplantation. In this study, the optimal time and temperature of antibiotic solution treatment for maintaining cellular viability with antibacterial effect were investigated. The antibiotic-nutrient solutions were composed of cefoxitin, lincomycin, vancomycin, and polymyxin B in RPMI-1640 medium. After various antibiotic solution treatment times (4, 8, and 12 h) and temperatures (4, 25, and 37 degrees C), the viabilities of cells dissociated from veins (jugular vein, femoral vein, superior vena cava, and inferior vena cava) were determined. Double staining by Griffonia simplicifolia agglutins-fluorescein isothiocyanate (GS1-FITC) and propidium iodide was used. To measure the antibacterial effect of the antibiotic solution, canine veins were artificially infected by 3 kinds of bacteria (Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae) and were treated by antibiotic solutions as viability test conditions. After the treatment with the antibiotic solution, the tissue was minced, and the homogenized tissue fraction was cultured on standard method agar. The colony that seemed to be resistant to the antibiotic solution was counted. At 37 and 25 degrees C, the viability of whole cells decreased significantly Asymptotic Significance 2-tailed (Asymp.Sig 2-tailed) < 0.05 after 4 h of antibiotic solution treatment, whereas at 4 degrees C it began to reduce significantly after 8 h of treatment. By antibiotic solution treatment at all 3 temperatures for 4 h, no significant difference in viability of the endothelial cells and whole cells was observed. To maintain the donor vein's cellular viability until transplantation, antibiotic solution treatment for 4 h at 4 degrees C is assumed to be appropriate.