Current therapies of organ failure or a wide range of tissue defect are often not ideal. Transplantation is the only effective way for long time survival. But it is hard to meet huge patients demands because of donor shortage, immune rejection and other problems. Tissue engineering could be a potential option. Choosing a suitable scaffold material is an essential part of it. According to different sources, tissue engineering scaffold materials could be divided into three types which are natural and its modified materials, artificial and composite ones. The purpose of tissue engineering scaffold is to repair the tissues or organs damage, so could reach the ideal recovery in its function and structure aspect. Therefore, tissue engineering scaffold should even be as close as much to the original tissue or organs in function and structure. We call it "organic scaffold" and this strategy might be the drastic perfect substitute for the tissues or organs in concern. Optimized organization with each kind scaffold materials could make up for biomimetic structure and function of the tissue or organs. Scaffold material surface modification, optimized preparation procedure and cytosine sustained-release microsphere addition should be considered together. This strategy is expected to open new perspectives for tissue engineering. Multidisciplinary approach including material science, molecular biology, and engineering might find the most ideal tissue engineering scaffold. Using the strategy of drawing on each other strength and optimized organization with each kind scaffold material to prepare a multifunctional biomimetic tissue engineering scaffold might be a good method for choosing tissue engineering scaffold materials. Our research group had differentiated bone marrow mesenchymal stem cells into bile canaliculi like cells. We prepared poly(L-lactic acid)/poly(ε-caprolactone) biliary stent. The scaffold's internal played a part in the long-term release of cytokines which mixed with sustained-release nano-microsphere containing growth factors. What's more, the stent internal surface coated with glue/collagen matrix mixing layer containing bFGF and EGF so could supplying the early release of the two cytokines. Finally, combining the poly(L-lactic acid)/poly(ε-caprolactone) biliary stent with the induced cells was the last step for preparing tissue-engineered bile duct. This literature reviewed a variety of the existing tissue engineering scaffold materials and briefly introduced the impact factors on the characteristics of tissue engineering scaffold materials such as preparation procedure, surface modification of scaffold, and so on. We explored the choosing strategy of desired tissue engineering scaffold materials.
Glucosides ; chemistry ; Humans ; Stents ; Tissue Engineering ; Tissue Scaffolds ; chemistry

BACKGROUND:An efficient blood vessel system has a decisive effect on the survival and function expression of cells in three-dimensional tissues. Therefore it has been a hot research field in tissue engineering to find an appropriate vascularization strategy.
OBJECTIVE:To summarize and discuss the theory and research progress in vascularization strategies.
METHODS:Literature search was performed in PubMed database for English literatures published from 2003 to 2013. The key words are“tissue engineering, vascularization, endothelial cell, scaffold”in English. Then, the papers were further analyzed and reviewed in line with the theme.
RESULTS AND CONCLUSION:A total of 124 papers were searched. At last, 41 papers were selected according to the titles and objectives. Vascularization is the focus and pressing issue in tissue engineering field. There are many vascularization strategies, such as growth factor delivery, cellco-culture, dynamic-culture by bioreactor, scaffolds or decellularized scaffolds. But none of them is recognized as an effective strategy to achieve functional anastomosis with the host and sustain grafts survival for a long time in vivo. It wil be a big breakthrough in the future to co-culture pluripotent stem cells with other stem cells, combine with growth factors and optimize culture conditions for the differentiation in vivo.

The quality of a donor liver after cardiac death is closely associated with energy metabolism during preservation. Ex vivo mechanical perfusion has broad application prospects because this technique can help energy metabolism and repair ischemia injury of donors' livers. Some core issues are presented in this review in order to provide references for propelling secure application of liver transplantation based on donation after cardiac death.
Death ; Humans ; Liver ; Liver Transplantation ; Organ Preservation ; methods ; Perfusion ; methods ; Warm Ischemia ; adverse effects

Objective To study the relationship between plasma creatinine and lactic acid levels in type 2 diabetic patients with normal renal function, and the effect of mefformiu administration on plasma lactic acid. Methods Blood samples were collected from 723 type 2 diabetic inpatients(275 cases treated with mefformin as treatment group and 448 without mefformin as control group). Plasma lactic acid was measured with enzyme-electrode assay. The fasting plasma glucose, fasting insulin, creatinine (Cr) , alanine aminotransferase (ALT), and HbA1C levels were also determined. Results (1) The lactic acid level in treatment group was significantly higher than that in control group [(1.33±0.57 vs 1.17±0.47) mmol/L, P<0.01] and so was the incidence of hyperlactacidemia (9.45% vs 4.91%, P<0.01). No lactic acidosis was found in all patients. (2) The correlation analysis showed that Cr, blood urea nitrogen, ALT and body mass index (BMI) were positively correlated with lactic acid in control group, and the positive correlation between Cr and lactic acid still existed (r= 0.345, P<0.01) after adjustment for ALT and BMI. (3) After being divided by 20 μmol/L Cr in control group, lactic acid levels in subgroup increased with the Cr levels, especially when Cr was over 90 μmol/L. The Cr cutpoint for predicting lactatemia was 95.35 μmol/L. Conclusion It is safe to administrate metformin in type 2 diabetic patients with normal renal function, along with low risk of lactic acidemia. The incidence of lactic acidemia may increase when plasma Cr level reaches 95.35 μmol/L,

Objective. To ascertain the relationship between the Ala54Thr variation of FABP2 gene and general as well as regional adipose tissue depots.Subjects. 165 subjects, in which 86 were subjects with normal glucose tolerance (NGT) [age 54.45±9.80, male/female 1.05,body mass index (BMI)26.48±4.01] and 79 were subjects with non-insulin-dependent diabetes mellitus (NIDDM)(age 55.86±10.00,male/female 1.08,BMI 26.75±3.30).Design and measurements. An association study of FABP2-Ala54Thr variation detected by PCR/HhaI digestion with general and regional adipose tissue depots determined by BMI and magnetic resonance imaging [abdominal subcutaneous and visceral adipose tissue area (SA and VA) and femoral subcutaneous adipose tissue area (FA)].Results. The geneotype and allele frequencies of FABP2-Ala54Thr variation in Chinese were quite close to the frequencies in American Caucasians and Pima Indians reported in the literature. Significant difference in genotype frequency distribution was observed between FA subgroups comparisons (FA≥75cm2 versus FA＜75cm2)in NIDDM subjects (X2＝11.460,P＝0.003),with significantly increased in Thr54-carrier[Thr54(+)]genotype frequency and Thr54 allele frequency in NIDDM subject with FA＜75cm2(odd ratio for genotype was 4.62,X2＝10.112,P＝0.001;and for allele＝2.36,X2＝5.379,P＝0.020).The FA in NIDDM-Thr54(+)subgroup was significantly lower than that in subjects with NIDDM-Thr54(-)sugroup(61.19±21.51cm2 versus 75.36±31.70cm2,P＝0.021). Stepwise regression analysis revealed that FABP2-Thr54 genotype variation was an independent factor contributing to the variation of FA in NIDDM(P＝0.003).Conclusion. FABP2 is associated with regional adipose tissue depot.The decreased femoral subcutaneous adipose tissue depot in NIDDM subjects is related to FABP2-Thr54 variant.

OBJECTIVETo evaluate the best cut-off point, sensitivity and specificity of body mass index (BMI), waist circumference (WC) and Waist-to-hip ratio (WHR) in predicting of abdominal visceral obesity.

METHODSAbdominal visceral fat area (VA) was measured with magnetic resonance image (MRI) in 690 subjects (men: 305, women: 385). Meanwhile, BMI, WC, WHR were assessed. Receiver operating characteristic (ROC) curve was used as index for analysis.

RESULTS1) 61.7% of over-weight/obesity (OW/OB) and 14.2% of normal weight (NW) individuals were abdominal visceral obesity (VA >/= 100 cm(2)) by MRI diagnosis. 2) VA was significantly positively correlated with anthropometric variables (BMI, WC, WHR), in which WC was the best (r = 0.73 - 0.77, P < 0.001). 3) The best cut-off points of these anthropometric parameters in assessing abdominal visceral obesity were as follow: BMI: 26 kg/m(2), WC: 90 cm, WHR: 0.93. Among them WC showed most sensitive and specific. 4) 95% men and 90% women appeared abdominal visceral obesity in subjects with BMI >/= 28 kg/m(2) or WC >/= 95 cm.

CONCLUSIONBMI, WC, WHR can all predict abdominal visceral obesity, with WC the best.

Adipose Tissue ; metabolism ; Adult ; Aged ; Aged, 80 and over ; Body Constitution ; Body Mass Index ; Female ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Obesity ; metabolism ; physiopathology ; Predictive Value of Tests ; Sensitivity and Specificity

OBJECTIVETo develop a method for preparing a decellularized scaffold based on human liver tissue.

METHODSA surgical specimen of the left lateral lobe of the liver was obtained from a patients with hepatic hemangioma. The decellularization process was performed by repeated freezing-thawing, sequential perfusion with 0.01% SDS, 0.1% SDS and 1% Triton X-100 through the portal vein, and sterilization with peracetic acid. L-02 cells were then engrafted onto the decellularized liver scaffold.

RESULTSHE staining, DAPI staining and scanning electron microscopy all verified the absence of residual cellular components in the decellularized scaffold. The residual DNA content in the decellularized scaffolds was 25.3∓14.6 ng/mg (dry weight), which was less than 1% of the total DNA content in a fresh human liver. Immunohistochemistry demonstrated that type I and IV collagens, fibronectin and elastin were all retained in the scaffold. The engrafted L-02 cells survived well on the scaffold with active proliferation and expressed albumin and G6pc.

CONCLUSIONIt is feasible to prepare decellularized scaffolds using surgical specimens of human liver, which can be a new approach to constructing a tissue-engineered liver for clinical purposes.

Humans ; Liver ; Microscopy, Electron, Scanning ; Octoxynol ; Perfusion ; Tissue Engineering ; Tissue Scaffolds

Objective To develop a method for preparing a decellularized scaffold based on human liver tissue. Methods A surgical specimen of the left lateral lobe of the liver was obtained from a patients with hepatic hemangioma. The decellularization process was performed by repeated freezing-thawing, sequential perfusion with 0.01% SDS, 0.1% SDS and 1% Triton X-100 through the portal vein, and sterilization with peracetic acid. L-02 cells were then engrafted onto the decellularized liver scaffold. Results HE staining, DAPI staining and scanning electron microscopy all verified the absence of residual cellular components in the decellularized scaffold. The residual DNA content in the decellularized scaffolds was 25.3± 14.6 ng/mg (dry weight), which was less than 1% of the total DNA content in a fresh human liver. Immunohistochemistry demonstrated that type I and IV collagens, fibronectin and elastin were all retained in the scaffold. The engrafted L-02 cells survived well on the scaffold with active proliferation and expressed albumin and G6pc. Conclusion It is feasible to prepare decellularized scaffolds using surgical specimens of human liver, which can be a new approach to constructing a tissue-engineered liver for clinical purposes.

Objective To develop a method for preparing a decellularized scaffold based on human liver tissue. Methods A surgical specimen of the left lateral lobe of the liver was obtained from a patients with hepatic hemangioma. The decellularization process was performed by repeated freezing-thawing, sequential perfusion with 0.01% SDS, 0.1% SDS and 1% Triton X-100 through the portal vein, and sterilization with peracetic acid. L-02 cells were then engrafted onto the decellularized liver scaffold. Results HE staining, DAPI staining and scanning electron microscopy all verified the absence of residual cellular components in the decellularized scaffold. The residual DNA content in the decellularized scaffolds was 25.3± 14.6 ng/mg (dry weight), which was less than 1% of the total DNA content in a fresh human liver. Immunohistochemistry demonstrated that type I and IV collagens, fibronectin and elastin were all retained in the scaffold. The engrafted L-02 cells survived well on the scaffold with active proliferation and expressed albumin and G6pc. Conclusion It is feasible to prepare decellularized scaffolds using surgical specimens of human liver, which can be a new approach to constructing a tissue-engineered liver for clinical purposes.

OBJECTIVETo optimize the protocols for isolation, in vitro culture, identification and induction of hepatic differentiation of rat bone marrow mesenchymal stem cells (BMSCs).

METHODSRat BMSCs were separated and purified by differential adherent culture for 1.5 h with the first medium change at 12 h. The surface markers of BMSCs were detected by flow cytometry. The cells were induced to differentiate into adipogenic, osteogenic, and chondrogenesis lineages. A 3-step protocol including sequential addition of growth factors, cytokines and hormones was used to induce the BMSCs to differentiate into hepatocyte-like cells.

RESULTSThe cells isolated using this protocol were positive for CD29, CD44, and CD90 and negative for CD29 and CD45. The adipogenic, osteogenic, and chondrogenic differentiation of the BMSCs were verified by Oil red, Alizarin red, and toluidine blue staining. The BMSCs induced with the 3-step protocol differentiated into hepatic-like cells that expressed hepatocyte-specific proteins (ALB and AFP) and genes.

CONCLUSIONThe optimized protocol allows simple and efficient isolation of highly purified populations of BMSCs, which can be induced into hepatic lineages in specific microenvironment.

Animals ; Cell Culture Techniques ; Cell Differentiation ; Flow Cytometry ; Hepatocytes ; cytology ; Mesenchymal Stromal Cells ; cytology ; Rats