Tissue engineering has evolved as a dynamic research field that encompasses multidisciplinary approaches involving cytology,material science,bioreactor engineering,and medicine.The overarching goal is to construct human tissue and organs in the laboratory for tissue regeneration or replacement.It offers a potential solution to the donor shortage in organ transplantation and to the difficulties in regenerative medicine.The basic components for tissue engineering include seed cell selection,bio-scaffold construction,and ex vivo tissue formation via a bioreactor. Over the past decade,tremendous progress has been made in bioengineering cartilage,trachea,urinary bladder,heart valve and endocrine tissues. However,there remain significant challenges in creating complex and human-sized tissues and organs for clinical use.In this article,we review the basic components and strategies for bioengineering organs. We attempt to provide an overview of current progress and challenges in developing organ-level tissue engineering and in the successful translation of bioengineered tissue and organ products into daily clinical practice.

Objective To compare the clinical outcomes of pre-emptive renal transplantation and transplantation after dialysis, and to evaluate the safety and advantages of pre-emptive renal transplantation. Methods The data of 50 cases of pre-emptive renal transplantation between January 1999 and January 2003 in our hospital were analyzed.Another 50 cases of renal transplantation after dialysis were selected as control group.The 2 groups were matched in the following variables:age,gender,blood type,cold (warm) ischemic time of the grafts,human leukocyte antigen (HLA),primary diseases, and use of immunosuppressants. The patient/allograft survival,incidence of rejection and delayed graft function were compared. Results The control patients (32/50) were more likely to have received blood transfusion before transplantation than patients of pre-emptive renal transplantation (14/50) (64% vs 28%, P

Objective To evaluate whether serum cystatin C (SCys C) could be used as an ideal index to assess renal function of renal transplant recipients during posttransplant follow-up.Methods Seventy patients who were followed up for at least 6 months after renal transplantation in our centre were recruited in the study. SCys C and serum creatinine (SCr) were determined during the follow-up period, and glomerular filtration rate (GFR) was measured using an isotope Tc99m DTPA.The correlation between SCys C, SCr and GFR was analyzed. The performance of SCys C and SCr in diagnosing the mild impairment of renal allgraft function (GFR ＜ 1 ml/s) was evaluated using ROC curve. Results Both SCys C and SCr had a linear negative correlation with GFR (r = -0. 82 and -0. 66 respectively, P＜0. 01 ). The sensitivity, specificity and positive predictive values (PPV) of SCys C for diagnosing the mild impairment of renal allgraft function were higher than those of SCr,but the AUC of SCys C did not differ from that of SCr significantly (0. 935 vs. 0. 877, P＞0. 05).Conclusion SCys C could be used an ideal index to evaluate the allograft renal function for its better correlation with actual GFR.

Objective To probe the indication, technique and effect of combined liver pancreas transplantation. Methods Donor organs were harvested by the technique of total abdominal evisceration. Simultaneous orthotopic liver and heterotopic pancreas duodenum transplantation was performed in one patient diagnosed as having chronic hepatitis B, hepatocirrhosis, hepatic cellular cancer, and insulin dependent diabetes. Liver and pancreas graft function was monitored after transplantation. Results The recipient recovered with excellent allograft function, and insulin independence was achieved without any surgical complication. Conclusion End stage liver disease with concomitant insulin dependent diabetes is the indication for combined liver pancreas transplantation.

Objective We summarized the clinical experience of modified ileal ureter substitution for treating long segment ureteral defection.Methods We retrospectively analyze the clinical data of 2 patients with long segment ureteral defect who treated with Yang-Monti ileal ureter substitution between March 2015 and November 2015.One 75 years old male patient was diagnosed as upper ureteral malignance and solitary kidney.The length of defection from renal pelvis to bladder was 22 em.His serum creatinine was 100 μmol/L,blood urea nitrogen was 5.7 mmol/L,serum chloride was 98 mmol/L.Another one 41 years old female patient was diagnosed as middle and lower ureteral iatrogenic injury.The traumatic length was 15 cm.Her serum creatinine was 70 μmol/L,blood urea nitrogen was 5.1 mmol/L,serum chloride was 100 mmol/L.they were both treated by Yang-Monti ileal ureter substitution.The ileal intestinal segment was used for the ureteral replacement,which were more than 15 cm to the ilealcecum.The length of intestine was 10.0 cm and 7.5 cm,respectively.The ileal mesentery was preserved.After closing the mesangial hiatus,the ileal segment was pull into the retroperitoneal space and pulling out via descending colonic mesangial window.The ileal segment was divided into three parts,which was 2.5 to 3.0 cm in each part.Each part was opened via long axis and then rotated 90 degree.The 4-0 absorable suture was used to suture the edge of each intestinal part continuously.The sutured intestine was re-tubularized,using 4-0 absorable suture and the F16 catheter was used as the tube model.The length of reconstructed ureter was 22 cm and 18 cm,respectively.The neo-ureter was re-anastomosed with renal pelvis and bladder wall.Two F6 double J stents were placed in the neo-ureter.Results The operative time was 160 min and blood loss was 200 ml in the first case.In the second case,the operative time was 180 min and blood loss was 220 ml.No significant complications were noticed intra-operation and post-operation.Six months after operation,the male patient's serum creatinine was 112 pmol/L,blood urea nitrogen was 6.1 mmol/L,serum chloride was 106.0 mmol/L and electrolytes were normal.In another patient,serum creatinine was 79 μmol/L,blood urea nitrogen was 5.9 mmol/L and serum chloride was 103.0 mmol/L.The GFR was 24.9 ml/min and 22.1 m]/min 3 and 6 months after operation,respectively.Ureteral obstruction wasn't detected on IVU images 3 months after operation.Conclusions For patient with long ureteral defect,which cannot be replaced by other urinary tissue,YangMonti ileal ureter substitution is one of the optional modalities.As a new technique of ureteral substitution,Yang-Monti ileal ureter substitution is simple and fewer complications and can improve the quality of life in patient compared with traditional ureteral substitution.

Objective To study the influential factors of tacrolimus'dosage and concentration differences between individuals in morning periods after renal transplantation.Methods The clinical data consisted of 118 receptors in morning periods after renal transplantation,whose immune suppressions were tacrolimus,mycophenolate and hormone.At 3,7,14 and 30 d after operation,all the receptors'weight,dosage of tacrolimus,dosage of hormone,diarrhea,blood fat,liver function,renal function,albumn and erythrocrit were recorded respectively,and at the same time their concentrations of tacrolimus and genetic polymorphisms of CYP3A5,MDRl 3435,MDR1 2677 and MDRl 1236 weredetected.Multiple linear regressions were performed.Results The fitting degrees of stepwise regression equations were low.At 3,7,14 and 30 d after operation,the adjusted R2was 0.284,0.267,0.417 and 0.324,respectively.From the aspect of pharmacogenomics,the main factors rela-ted to the differences of tacrolimus'dosage and concentration included MDR1 2677,MDRl 1236 and MDR13435,which varied intensively.Age,albumn,renal function,blood fat and liver function were important factors too.Conclusions The main reasons of the differences of tacrolimus'dosage and concentration between individuals in morning periods after renal transplantation are medicines and changes of internal environment after operation.The genetic polymorphisms of MDR1,age,albumn,renal runetion.blood fat and liver function are important factors too.

Objective To investigate a possible association of donor-recipient compatibility for ABO blood group alleles with acute rejection (AR) in renal transplantation. Methods A study comprising 87 pairs of donor and recipient was performed. The ABO genotype A1, A2, O1, O2, and B alleles of renal transplanted recipients and their respective donors were assessed by PCR amplification with sequence-specific primers (PCR-SSP). Accordingly, recipients were divided into donor-recipient ABO genotype matched and mismatched groups. Results The PCR-SSP based types of all cases showed total concordance with their serologically assigned ABO groups. Fifty pairs (57. 5%) were matched for ABO genotype among the 87 pairs of donor and recipient while 37 (42. 5%) were mismatched, including 1 allele mismatch in 31 pairs (83.8%), 2 alleles mismatches in 6 pairs (16. 2%).The incidence of AR was 12.0% (6 cases) and 29. 7% (11 cases) for ABO genotype matched and mismatched transplant patients, respectively ( P ＜ 0.05). After high dose methylprednisolone (MP)treatment, all cases exepienced reversion of AR except a A2O1 recipient receiving kidney from a A1O1enced 4 AR episodes within 3-10 months, and the period of AR was gradually shortened. After high dose MP was administered empirically, even though short-term improvement of renal function was observed, the serum creatinine continued to increase progressively with decreased efficacy of high dose MP. One year after operation the serum creatinine rose to 441 μmol/L. Conclusions Simultaneous definition of the ABO genotype and HLA is highly feasible. The A2 patient is suitable for receiving kidneys from blood group O donors. DNA mismatch for ABO genotype of renal transplant recipients and their respective donors is an independent risk factor for AR. Genotyping of ABO blood group is conducive to prevent AR.

Objective To summarize the clinical experience of combined liver and kidney transplantation (CLKT). Methods CLKT was performed on 22 patients. The orthotopic liver transplantation (LT) was preceded with the classic fashion in 10 patients and piggyback fashion in 12 patients. The renal allograft was implanted to the iliac fossa routinely. After operation, the patients received an induction therapy with anti-CD25 monoclonal antibody or antithymocyte globulin ( ATG) and a maintenance therapy with tacrolimus (Tac), mycophenolate mofetil and prednisone. Results The CLKT was successfully performed on all 22 patients, and the graft function was restored well postoperation. During the perioperative period, an acute rejection episode of liver occurred in one patient and acute renal allograft rejection episode in 2 patients. The Tac toxicity occurred in one patient. The hemorrhage of digestive tract occurred in one recipient and the hemorrhage of peritoneal cavity in one patient. The pleural effusion occurred in 6 recipients. The pneumonia occurred in 2 cases and the peritoneal infection in one patient During a follow-up period of 6 months to 7 years 11 months, three patients died because of cytomegalovirus pneumonia in 2 patients and acute myocardial infarction in, one patient, The 1-, 3-, 5-year survival rate of recipients was 86,4 %, 81.3 %, 72.7 % respectively. Conclusion The CLKT is an effective method for treatment of patients with end-stage liver djsease and chronic renal failure.

Objective To explore the relationship of serum anti-MICA antibody and development of chronic rejection (CR) after renal transplantation. Methods The enrolled 105 patients included 43 cases of CR, and 62 cases of functioning renal allograft as controls. Data including PRA level before transplantation, HLA mismatch, cold ischemic time, SCr at discharge, immunosuppressive regimen,and months after transplantation were analyzed. Blood samples were collected immediately after grouping for anti-MICA antibodies, SCr determination. Acute rejection episodes and renal allograft function which was evaluated by △SCr/M [(SCr at present - SCr at discharge) /months after transplantation) were compared between anti-MICA-antibody positive patients and anti-MICA-antibody negative patients. Results There was no significant difference in gender, age, HLA mismatch, cold ischemic time, immunosuppressive regimen, SCr at discharge, months after transplantation between CR and control groups (P＞0.05). Serum creatinine level and number of antiMICA-antibody positive patients in CR group were significantly increased as compared with those in control group (P＜0.01 ). Acute rejection episodes during the first 3 months after transplantation in anti-MICA-antibody positive patients were significantly more than those in anti-MICA-antibody negative patients (P＜0.05),and the △SCr/M in the former was higher than that in the latter (8.3 +3.6 vs 2.4 ± 2.6, P＜0.05). Conclusion Humoral immunoreaction mediated by MICA partly participates the development of CR after renal transplantation. MICA antibody is a risk factor affecting long-term allograft function.

Objective To investigate expression and suppressive function of CD39 + regulatory T cells (Treg) in kidney transplant recipients.Method Thirty recipients of first kidney transplants were treated with tacrolimus,mycophenolate mofetil and prednisone.Within 28 days posttransplantation,there were 14 patients subject to acute rejection (AR group),and the rest 16 patients had no episodes of acute rejections (NR group).Twelve healthy volunteers served as healthy controls (HC group).We collected peripheral blood from the three groups and separated PBMC by density gradient centrifugation,and sorted Tresp,CD39-Treg and CD39+ Treg by flow cytometry.We next analyzed the ratio of CD39 + Treg/CD4+ T cells.ELISA was used to determine the suppressive ability of CD39-Treg and CD39+ Treg on secretion of IFN-γ and IL-17 by Tresp.Results The ratio of CD39 + Treg/CD4 + T cells in AR group was significantly reduced as compared with HC group and NR group (P＜0.05).In HC group and NR group,the secretion of IFN-γ and IL-17 by Tresp was suppressed significantly (P＜0.05) by CD39+ Treg.CD39Treg could suppress secretion of IFN-γ but not IL-17 production by Tresp.CD39+ Treg in AR group AR could suppress the secretion of IFN-γ significantly (P＜0.01),but not to IL-17 production.Conclusion CD39+ Treg have important immunoregulation function.The relative amount of CD39+ Treg was reduced and their regulatory function was impaired in patients with acute rejection.