J.B. Park

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.

Discovery and Validation of Biomarkers That Distinguish Mucinous and Nonmucinous Pancreatic Cysts

The use of advanced imaging technologies for the identification of pancreatic cysts has become widespread. However, accurate differential diagnosis between mucinous cysts (MC) and nonmucinous cysts (NMC) consisting of pseudocysts (NMC1) and nonmucinous neoplastic cysts (NMC2) remains a challenge. Thus, it is necessary to develop novel biomarkers for the differential diagnosis of pancreatic cysts. An integrated proteomics approach yielded differentially expressed proteins in MC that were verified subsequently in 99 pancreatic cysts (21 NMC1, 41 NMC2, and 37 MC) using a method termed GeLC-stable isotope dilution-multiple reaction monitoring-mass spectrometry (GeLC-SID-MRM-MS) along with established immunoassay techniques. We identified 223 proteins by nanoscale liquid chromatography coupled to tandem mass spectrometry (nano LC/MS-MS). Nine candidate biomarkers were identified, including polymeric immunoglobulin receptor (PIGR), lipocalin 2 (LCN2), Fc fragment of IgG-binding protein (FCGBP), lithostathine-1-alpha (REG1A), afamin (AFM), chymotrypsin C (caldecrin; CTRC), amylase, alpha 2B (pancreatic; AMY2B), lectin, galactoside-binding, soluble, 3 binding protein (LGALS3BP), and chymotrypsin-like elastase family, member 3A (CELA3A), which were established as biomarker candidates for MC. In particular, we have shown that a biomarker subset, including AFM, REG1A, PIGR, and LCN2, could differentiate MC not only from NMC (including NMC1) but also from NMC2. Overall, the MS-based comprehensive proteomics approach used in this study established a novel set of candidate biomarkers that address a gap in efforts to distinguish early pancreatic lesions at a time when more successful therapeutic interventions may be possible.

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.

Subunit-specific mass spectrometry method identifies haptoglobin subunit alpha as a diagnostic marker in non-small cell lung cancer.

UNLABELLED Haptoglobin (Hp) subunits have been suggested as a potential serum marker for lung cancer. Research is intense on the application of Hp subunits to predict the cancer earlier. Nevertheless, it remains difficult to accurately measure the content of Hp subunits. We developed stable isotope dilution-multiple reaction monitoring mass spectrometry (SID-MRM-MS) capable of measuring Hp subunits (alpha and beta chains). Three isotopic analogs (NPANPVQ, TEGDGVYTLNDK and ILGGHLDAK for alpha, alpha2 and beta chain, respectively) were used as internal standard (IS) for SID-MRM-MS. Serum levels of each Hp subunit were measured in 210 clinical samples using SID-MRM-MS. A concentration ratio of each Hp subunit to total Hp was investigated. Secretion levels of alpha and beta chains were significantly increased in non-small cell lung cancer (NSCLC) compared to controls (P<0.0001). Alterations of the alpha chain ratio were more apparent than beta chain between controls and NSCLC (P=0.0001 and 0.338 for alpha and beta chains, respectively). In conclusion, this study provides not only an efficient quantitative method to determine each Hp subunit in crude sera, but also evidence that Hp alpha chain is a more prospective biomarker to diagnose NSCLC than beta chain. BIOLOGICAL SIGNIFICANCE Recent several studies have reported Hp as a potential biomarker for diagnosis of lung cancer. However a successful evaluation of the value of Hp subunits was not achieved on clinical samples. To evaluate the diagnostic performance of each Hp subunit, the development of an accurate quantitative assay of Hp subunits is necessary. In this regard, we employed a new analytical method using stable isotope dilution-multiple reaction monitoring mass spectrometry (SID-MRM-MS), capable of measuring Hp subunits in 210 clinical specimens. In this article, we measured the Hp subunit concentrations and Hp subunits/total Hp ratios in patients with NSCLC using SID-MRM-MS. This is the first report on the evaluation of each Hp subunit as a lung cancer marker using SID-MRM-MS. Consequently, we evaluated specific three tryptic peptides (e.g. NPANPVQ, TEGDGVYTLNDK and ILGGHLDAK for alpha, alpha2 and beta chain, respectively) with high specificity and sensitivity for determination of Hp subunits. Through future large prospective cohort studies, the clinical application of Hp subunits as complementary markers, especially Hp alpha, would be useful for the diagnosis of NSCLC.

Reconstitution of Human Lymphocytes Following Ex Vivo Expansion of Human Umbilical Cord Blood CD34+ Cells and Transplantation in Rag2-/-γc-/-Mice Model

BACKGROUND Due to ethical issues, in vivo studies of the human immune system have been difficult. Thus, small-animal xenotransplantation models have been employed, although they scarcely sustain a human immune response. In this study, we compared human cell repopulation tendencies and functionality in Rag2-/- gamma c-/- mice following various ex vivo expanded human hematopoietic stem cells (HSCs). METHODS Human umbilical cord blood (UCB) CD34+ cells were cultured for 7 days with a cytokine combination of stem cell factor, Flk2/Flt3 ligand, and thrombopoietin, with absence or presence of rhIL-3, then transplanted into Rag2-/- gamma c-/- mice. Reconstituted human lymphocytes were analyzed based on the expression of CD45 as well as CD3, CD19, and CD56 in peripheral blood (PB) until 16 weeks after transplantation. BrdU assay and functional analysis of reconstituted human lymphocytes used PHA- or rhIL-2-stimulated splenocytes and bone marrow cells from recipient mice. RESULTS The percentage of human CD45dim cells, not CD45bright cells, in PB of mice transplanted with cultured HSCs with rhIL-3 was much higher than in the group without rhIL-3 (approximately 2.5-fold at week 10 posttransplantation). The humanized mice showed systemic repopulation with a comprehensive array of human lymphohematopoietic cells, including T, B, natural killer (NK) cells, and even dendritic cells. However, the expression level was also dim. The number of CD3+ T cells and CD56+ NK cells was especially increased in the presence of rhIL-3. In addition, after in vitro restimulation proliferation assays and NK activity of interferon-gamma secretion showed greater effects in the presence of rhIL-3. CONCLUSION These data suggested that the development of a diverse repopulation of human lymphocytes was possible in Rag2-/- gamma c-/- mice after transplantation of cultured UCB CD34+ HSCs with interleukin-3.

Multi-layered Representation for Cell Signaling Pathways

To understand complex signaling pathways and networks, it is necessary to develop a formal and structured representation of the available information in a format suitable for analysis by software tools. Due to the complexity and incompleteness of the current biological knowledge about cell signaling, such a device must be able to represent cellular pathways at differing levels of details, one level of information abstract enough to convey an essential signaling flow while hiding its details and another level of information detailed enough to explain the underlying mechanisms that account for the signaling flow described at a more abstract level. We have defined a formal ontology for cell-signaling events that allows us to describe these cellular pathways at various levels of abstraction. Using this formal representation, ROSPath (reactive oxygen species-mediated signaling pathway) database system has been implemented and made available on the web (rospath.ewha.ac.kr). ROSPath is a database system for reactive oxygen species (ROS)-mediated cell signaling pathways and signaling processes in molecular detail, which facilitates a comprehensive understanding of the regulatory mechanisms in signaling pathways. ROSPath includes growth factor-, stress-, and cytokine-induced signaling pathways containing about 500 unique proteins (mostly mammalian) and their related protein states, protein complexes, protein complex states, signaling interactions, signaling steps, and pathways. It is a web-based structured repository of information on the signaling pathways of interest and provides a means for managing data produced by large-scale and high-throughput techniques such as proteomics. Also, software tools are provided for querying, displaying, and analyzing pathways, thus furnishing an integrated web environment for visualizing and manipulating ROS-mediated cell-signaling events.

Large-scale clinical validation of biomarkers for pancreatic cancer using a mass spectrometry-based proteomics approach

We performed an integrated analysis of proteomic and transcriptomic datasets to develop potential diagnostic markers for early pancreatic cancer. In the discovery phase, a multiple reaction monitoring assay of 90 proteins identified by either gene expression analysis or global serum proteome profiling was established and applied to 182 clinical specimens. Nine proteins (P < 0.05) were selected for the independent validation phase and quantified using stable isotope dilution-multiple reaction monitoring-mass spectrometry in 456 specimens. Of these proteins, four proteins (apolipoprotein A-IV, apolipoprotein CIII, insulin-like growth factor binding protein 2 and tissue inhibitor of metalloproteinase 1) were significantly altered in pancreatic cancer in both the discovery and validation phase (P < 0.01). Moreover, a panel including carbohydrate antigen 19-9, apolipoprotein A-IV and tissue inhibitor of metalloproteinase 1 showed better performance for distinguishing early pancreatic cancer from pancreatitis (Area under the curve = 0.934, 86% sensitivity at fixed 90% specificity) than carbohydrate antigen 19-9 alone (71% sensitivity). Overall, we present the panel of robust biomarkers for early pancreatic cancer diagnosis through bioinformatics analysis that combined transcriptomic and proteomic data as well as rigorous validation on a large number of independent clinical samples.