G.S. Choi

Isolation and Characterization of Mouse Mesenchymal Stem Cells

OBJECTIVE Mesenchymal stem cells (MSCs) have been studied in regenerative medicine because of their unique immunologic characteristics. However, before clinical application in humans, animal models are needed to confirm their safety and efficacy. To date, appropriate methods and sources to obtain mouse MSCs have not been identified. Therefore, we investigated MSCs isolated from 3 strains of mice and 3 sources for the development of MSCs in a mouse model. MATERIALS AND METHODS Male BALB/c, C3H and C57BL/6 mice were used to isolate MSCs from various tissues including bone marrow (BM), compact bone, and adipose tissue. The MSCs were maintained in StemXVivo medium. Immunophenotypes of the MSCs were analyzed by FACS and their growth potential estimated by the number of colony-forming unit fibroblasts. RESULTS All MSCs that were isolated from BM, compact bone, and adipose tissue showed plastic-adherent, fibroblastic-like morphologic characteristics regardless of the mouse strain or cell source. However, culture of BM MSCs was less successful than the other tissue types. The FACS phenotype analysis revealed that the MSCs were positive for CD29, CD44, CD105, and Sca-1, but negative for CD34, TER-119, CD45, and CD11b. According to the results of the characterization, the adipose tissue MSCs showed higher growth potential than did other MSCs. CONCLUSION The results of this study showed that culture of adipose tissue and compact bone-MSCs was easier than BM MSCs. Based on the results of immunophenotype and growth potential, C57BL/6 AT-MSCs might be a suitable source to establish a mouse model of MSCs.

Clinical Significance of Posttransplantation Vesicoureteral Reflux During Short-Term Period After Kidney Transplantation

BACKGROUND Urinary tract infection (UTI) may occur in the form of asymptomatic bacteruria but severe cases may cause life-threatening pyelonephritis or sepsis in immunosuppressed kidney transplant recipients. Vesicoureteral reflux (VUR) is one risk factor in the transplanted kidney. But controversy exists regarding the effect of VUR in terms of graft outcomes. The objective of this study was to analyze the clinical outcomes among patients with posttransplantation VUR. PATIENTS AND METHODS Between April 2005 and June 2006, we examined 75 patients with functioning grafts for more than 1 year by voiding cystourethrography at 1 year for the grade of posttransplantation VUR: group A, absent (n = 28) including grade I (n = 6) and II (n = 22); group B, including grade III (n = 17) and IV (n = 2). Patient characteristics included etiology of end-stage renal disease, duration of dialysis before transplantation, serum creatinine, creatinine clearance at 1 and 12 months after transplantation, and postoperative complications. The presence/absence of UTI, acute rejection, and graft loss were compared for significance. RESULT Posttransplantation VUR present in 47/75 patients (61.3%) was over grade III in 19 patients. There was no difference in significant risk factors between the groups as well as between the reflux subgroups. VUR did not influence graft function with the only significant factor being acute cellular rejection. CONCLUSION We failed to confirm a risk of developing posttransplantation VUR. Posttransplantation VUR did not negatively affect graft function; acute cellular rejection was the only factor that influenced it. Longer follow-up needs to be performed to clarify the long-term effects of posttransplantation VUR on graft function.

Renal Transplantation in Patients With a Small Bladder

BACKGROUND In patients undergoing kidney transplantation with a small bladder, many surgeons are faced with technical difficulties about the implantation as well as about satisfactory bladder rehabilitation. The objective of this study was to clarify the clinical outcomes of patients with end-stage renal disease who had a bladder capacity of less than 100 mL on preoperative voiding cystourethrogram after renal transplantation using extravesical ureteroneocystostomy. PATIENTS AND METHODS We retrospectively studied 345 patients with end-stage renal disease who underwent renal transplantation between April 2002 and June 2006. These patients were classified into two groups according to their preoperatively estimated bladder capacity using a voiding cystourethrogram. Group A had a bladder capacity of less than 100 mL (n = 23; 6.7%) and group B had a capacity of 100 mL or more (n = 322; 93.3%). For each group, the clinical outcome, including serum creatinine level at 1 month and 1 year after transplantation, bladder capacity, surgical complications, and prevalence of urinary tract infection (UTI) requiring hospital admission were recorded and the graft survival rate calculated. RESULTS Compared with group B, group A had undergone a longer duration of dialysis and required cadaveric kidney transplantation more frequently (P < .05). Postoperative surgical complications occurred in nine cases. There was no difference in the frequency of surgical complications and UTI requiring hospital admission between group A and group B. At 1 year posttransplant, bladder capacity was 342.0 +/- 43.8 mL (range, 300-400 mL) and 429.1 +/- 75.9 mL (range, 200-500 mL), respectively (P = .015). There was no statistical difference between the groups in the serum creatinine level and the graft survival rate at 5 years after transplantation (100% vs 92.4%). CONCLUSIONS Similar to patients with a normal bladder size, renal transplantation can be successfully achieved in patients with a small bladder. Attempts to increase the bladder capacity by programmed training of the bladder and bladder expansion by surgical intervention seem unnecessary.

Living Donor Liver Transplantation in Budd-Chiari Syndrome: A Single-Center Experience

Budd-Chiari syndrome (BCS), which is characterized by hepatic venous outflow obstruction due to occlusion of the major hepatic vein and/or the inferior vena cava (IVC), is rare. Traditionally, a caval resection is advocated for these patients; however, such a maneuver renders living donor liver transplantation (LDLT) impossible. We encountered BCS in 4/377 LDLT patients during a 5-year period (January 2003 to December 2007). This report examine the various surgical modifications in these 4 patients, who underwent to LDLT for BCS. Resection of right hepatic vein (RHV) with an adjacent fibrotic part of the IVC with direct anastomosis of the graft RHV to the IVC was performed in 2 patients. One patient underwent retrohepatic IVC excision and reconstruction with a cryopreserved autologous IVC graft. The fourth patient, with a preexisting mesoatrial shunt for BCS, underwent conversion of this to a RHV atrial shunt. Graft and patient survivals were 100%. There were few complications in either donors or recipients. LDLT for BCS can be performed safely with adequate venous drainage techniques and with anticoagulant therapy and good follow-up for early diagnosis and treatment of recurrence leading to excellent long-term results.

The Risk Factors of Delayed Graft Function and Comparison of Clinical Outcomes After Deceased Donor Kidney Transplantation: Single-Center Study

INTRODUCTION The aim of this study was to analyze risk factors for delayed graft function (DGF) after deceased donor kidney transplantation and to compare the clinical outcomes of non-DGF versus DGF recipients. PATIENTS AND METHODS From January 2004 to June 2008, 75/154 kidneys were transplanted into 74 recipients. We classified the recipients into two groups: group 1 (n=61) without DGF and group 2 (n=13) with DGF. RESULTS On univariate analysis, recipient age (P=.048) cause of brain death (traumatic brain injury vs disease, P=.016), blood urea nitrogen (P=.002), serum creatinine (P=.001), arterial pH (P=.019), and serum sodium level (P=.012) just before organ procurement showed significant differences. On multivariate analysis, the cause of brain death (P=.015, hazard ratio [HR]: 7.086), the terminal serum creatinine>or=1.5 mg/dL before organ procurement (P=.007, HR: 10.132), and recipient age over >or=50 years (P=.021, HR: 7.767) were independent risk factors for the development of DGF. Graft failures occurred among 5/74 recipients with 5-year graft survivals between group 1 and group 2 of 91.7% and 84.6%, respectively. Patient death occurred in five cases, most by due to infection. The 5-year patient survival between groups 1 and 2 were 93.9% and 84.6%, respectively (P = .106). CONCLUSION The independent risk factors for DGF were the cause of brain death, the terminal creatinine level, and the recipient age. In deceased donor kidney transplantation, DGF may have less effect on long-term patient and graft survivals.

Can Preemptive Kidney Transplantation Guarantee Longer Graft Survival in Living-Donor Kidney Transplantation? Single-Center Study

INTRODUCTION The benefit of preemptive kidney transplantation (KTx) for graft survival compared with nonpreemptive KTx is controversial. OBJECTIVE To analyze the influence of preemptive KTx on graft survival. PATIENTS AND METHODS The study included 476 of 531 patients who had undergone living-donor KTx between January 2000 and June 2007. Pediatric patients and those who had previously undergone KTx were excluded. Recipients were divided into 2 groups; group 1 included 413 patients (86.8%) who received grafts after institution of maintenance dialysis, and group 2 included 63 patients (13.2%) who underwent preemptive KTx. RESULTS Donor type and HLA mismatch demonstrated significant differences between the 2 groups. Group 1 had more living donors and fewer HLA mismatches. Warm ischemia time in group 2 was significantly shorter than in group 1. The serum creatinine concentration in group 1 on postoperative day 7 was significantly higher than in group 2. Five- and 10-year graft survival in groups 1 and 2, respectively, were 95.3% and 81.3% vs 92.9% and 92.9%. Graft survival was not significant insofar as duration and method of dialysis. At our institution, independent risk factors for graft survival in living-donor KTx are primary end-stage renal disease, acute cellular rejection episodes, and recipient age. CONCLUSION We observed no benefit on graft survival in recipients of living-donor KTx insofar as whether they had undergone previous dialysis.

Risk factors for posttransplant lymphoproliferative disorder in pediatric liver transplant recipients with cytomegalovirus antigenemia.

Epstein-Barr virus (EBV) infections, associated with posttransplant lymphoproliferative disorder (PTLD) are known to develop in cytomegalovirus (CMV)-infected transplant recipients due to the indirect effects of CMV. This study evaluated risk factors for PTLD among pediatric liver transplant recipients with CMV infections. We reviewed the medical records of 119 patients<or=18 years old who underwent liver transplantation between September 1996 and April 2009. Sixty-six subjects (55.5%) displayed CMV antigenemia during the study period; 15 (12.6%) developed PTLD. Of these, 10 developed PTLD after CMV antigenemia. The other patients (n=5) were excluded due to negative CMV antigenemia. The incidence of PTLD influenced by CMV infection was not significantly different from the incidence of PTLD without underlying CMV (P=.258). There were no differences in age, gender, antiviral prophylaxis, type of liver transplantation, or acute rejection episodes in the incidence of between patients with versus without PTLD. EBV but not CMV high-risk groups were a predictor for the development of PTLD (P=.035). CMV syndrome, tissue-invasive CMV disease, and CMV peak titer were not associated with an increased risk of PTLD. The primary risk factor for PTLD was EBV high-risk patients (donor positive/recipient negative). CMV disease was not associated with PTLD in pediatric liver transplant recipients with CMV infections.

Comparison of Outcomes of Living and Deceased Donor Kidney Grafts Surviving Longer Than 5 Years in Korea

BACKGROUND It is generally recognized that living donor kidney transplantation (LDKT) grafts are superior to deceased donor kidney transplantation (DDKT) grafts. We compared survival and functional outcomes of LDKT and DDKT grafts. METHODS Among 1000 kidneys transplanted from 1995 to 2008, we selected grafts surviving >5 years, excluding pediatric, multi-organ transplantation, and retransplantations (n=454). RESULTS There were 179 kidneys from deceased donors and 275 from living donors. Recipients showed no difference in age, gender, or cause of renal failure. Donors were younger in the DDKT group (30.6 vs 38.5 years; P<.05). There were more male donors in the DDKT group (73.2% vs 54.5%; P<.05). Deceased donors showed a greater mean number of HLA mismatches (4.2 vs 2.7; P<.05). Death-censored graft survival at 10 years showed no difference (DDKT 88.9% vs LDKT 88.9%; P=.99). Mean serum creatinine at 5 years was 1.41 mg/dL for DDKT and 1.44 mg/dL for LDKT (P=.75). Mean estimated glomerular filtration rate at 5 years was 67.8 mL/min/1.73 m2 for DDKT and 62.1 mL/min/1.73 m2 for LDKT (P=.23). Twenty-three DDKT grafts (12.8%) and 47 LDKT grafts (17.1%) experienced acute rejection episodes (P=.22). DDKT recipients showed more cases of viral and bacterial infections compared with LDKT recipients (viral, 11.7% vs 2.2% [P<.05]; bacterial, 21.8% vs 7.3% [P<.05]). CONCLUSION Among kidney grafts surviving >5 years, there was no difference in survival or serum creatinine levels at 5 and 10 years between DDKT and LDKT grafts.

Development of Functional Human Immune System With the Transplantations of Human Fetal Liver/Thymus Tissues and Expanded Hematopoietic Stem Cells in RAG2―/―γc―/― MICE

BACKGROUND There is an increasing need for suitable animal models for the study of the human immune system and disease. The purpose of this study was to develop a practical in vivo model of human immune cell repopulation using ex vivo expanded human fetal liver-derived CD34(+) hematopoietic stem cells and subrenally coimplanted fetal liver/thymus tissues. METHODS Freshly isolated fetal liver-derived CD34(+) hematopoietic stem cells were frozen until injected and ex vivo expanded with various cytokines for 7 days. After fetal liver/thymus tissues were subrenally coimplanted into preirradiated Rag2(-/-)gamma(c)(-/-) mice, frozen and ex vivo expanded CD34(+) cells were injected intravenously. The peripheral blood of the mice was monitored for the detection of human cell engraftment using flow cytometry. Then we confirmed human T-cell function by in vitro function assays. RESULTS After fetal liver/thymus tissues were coimplanted into the irradiated Rag2(-/-)gamma(c)(-/-) mice, with frozen and ex vivo expanded CD34(+) hematopoietic stem cells, human cell engraftments were determined using hCD45 and multilineage markers. The cultured cells with the cytokine combination of stem cell factor, thrombopoietin, Flk2/Flk3 ligand (FL), and interleukin-3 showed stable and long-term engraftment compared to other combinations. The ex vivo expanded human fetal liver-derived CD34(+) hematopoietic stem cells, under our culture conditions, accomplished a large volume of expanded cells that were sustained, demonstrating self-renewal of the evaluated markers, which may have indicated long- term repopulation activity. CONCLUSION The results of this study demonstrated a practical mouse model of expanded human immune cells especially T cells in Rag2(-/-)gamma(c)(-/-) mice.

Patients With Unresectable Hepatocellular Carcinoma Beyond Milan Criteria: Should We Perform Transarterial Chemoembolization or Liver Transplantation?

Patients with unresectable, beyond Milan criteria, hepatocellular carcinoma (HCC) invariably undergo palliative transarterial chemoembolization (TACE). The aim of this study was to compare the outcomes of conventional TACE versus liver transplantation (LT) in unresectable (beyond Milan criteria) HCC. Twelve patients underwent LT and 86 TACE for unresectable, beyond Milan criteria HCC. The inclusion criteria were a single tumor<or=6.5 cm or <or=5 tumors and all tumors<or=5 cm based on initial radiologic findings. We excluded patients with double primary cancers, age>60 years, vascular invasion, or extrahepatic spread. Survival rates were calculated using the Kaplan-Meier method. Multivariate analysis showed that TACE was a prognostic factor for survival (hazard ratio, 16.66, P=.000). The LT group showed significantly better survival than the TACE cohort. Two cases (16.7%) in the LT group recurred at a median time of 13.5 months. Survival rates at 1, 3, and 5 years were 100%, 88.9%, and 76.2% in the LT group, and 85.6%, 45.6%, and 21.4% in the TACE group, respectively. Patients with unresectable, beyond Milan criteria HCC should be given the option to receive LDLT, because LT offers a significantly better likelihood of survival than TACE.