Choon Hyuck David Kwon

Lysophosphatidylcholine as a death effector in the lipoapoptosis of hepatocytes

The pathogenesis of nonalcoholic steatohepatitis (NASH) is unclear, despite epidemiological data implicating FFAs. We studied the pathogenesis of NASH using lipoapoptosis models. Palmitic acid (PA) induced classical apoptosis of hepatocytes. PA-induced lipoapoptosis was inhibited by acyl-CoA synthetase inhibitor but not by ceramide synthesis inhibitors, suggesting that conversion products other than ceramide are involved. Phospholipase A2 (PLA2) inhibitors blocked PA-induced hepatocyte death, suggesting an important role for PLA2 and its product lysophosphatidylcholine (LPC). Small interfering RNA for Ca2+-independent phospholipase A2 (iPLA2) inhibited the lipoapoptosis of hepatocytes. PA increased LPC content, which was reversed by iPLA2 inhibitors. Pertussis toxin or dominant-negative Gαi mutant inhibited hepatocyte death by PA or LPC acting through G-protein-coupled receptor (GPCR)/Gαi. PA decreased cardiolipin content and induced mitochondrial potential loss and cytochrome c translocation. Oleic acid inhibited PA-induced hepatocyte death by diverting PA to triglyceride and decreasing LPC content, suggesting that FFAs lead to steatosis or lipoapoptosis according to the abundance of saturated/unsaturated FFAs. LPC administration induced hepatitis in vivo. LPC content was increased in the liver specimens from NASH patients. These results demonstrate that LPC is a death effector in the lipoapoptosis of hepatocytes and suggest potential therapeutic values of PLA2 inhibitors or GPCR/Gαi inhibitors in NASH.

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.

Safety of small-for-size grafts in adult-to-adult living donor liver transplantation using the right lobe.

The problem of graft size is one of the critical factors limiting the expansion of adult‐to‐adult living donor liver transplantation (LDLT). We compared the outcome of LDLT recipients who received grafts with a graft‐to‐recipient weight ratio (GRWR) < 0.8% or a GRWR ≥ 0.8%, and we analyzed the risk factors affecting graft survival after small‐for‐size grafts (SFSGs) were used. Between June 1997 and April 2008, 427 patients underwent LDLT with right lobe grafts at the Department of Surgery of Samsung Medical Center. Recipients were divided into 2 groups: group A with a GRWR < 0.8% (n = 35) and group B with a GRWR ≥ 0.8% (n = 392). We retrospectively evaluated the recipient factors, donor factors, and operative factors through the medical records. Small‐for‐size dysfunction (SFSD) occurred in 2 of 35 patients (5.7%) in group A and in 14 of 392 patients (3.6%) in group B (P = 0.368). Graft survival rates at 1, 3, and 5 years were not different between the 2 groups (87.8%, 83.4%, and 74.1% versus 90.7%, 84.5%, and 79.4%, P = 0.852). However, when we analyzed risk factors within group A, donor age and middle hepatic vein tributary drainage were significant risk factors for graft survival according to univariate analysis (P = 0.042 and P = 0.038, respectively). Donor age was the only significant risk factor for poor graft survival according to multivariate analysis. The graft survival rates of recipients without SFSD tended to be higher than those of recipients with SFSD (85.3% versus 50.0%, P = 0.074). The graft survival rates of recipients with grafts from donors < 44 years old were significantly higher than those of recipients with grafts from donors ≥ 44 years old (92.2% versus 53.6%, P = 0.005). In conclusion, an SFSG (GRWR < 0.8%) can be used safely in adult‐to‐adult right lobe LDLT when a recipient is receiving the graft from a donor younger than 44 years. Liver Transpl 16:864–869, 2010.

Recurrence of hepatitis B is associated with cumulative corticosteroid dose and chemotherapy against hepatocellular carcinoma recurrence after liver transplantation

The incidence of hepatitis B (HB) recurrence after a liver transplantation has been reduced by prophylaxis with hepatitis B immunoglobulin (HBIG) and lamivudine. However, the long‐term incidence of recurrence is <10%, and the factors associated with HB recurrence are unclear. This study analyzed the factors associated with HB recurrence in 203 recipients who underwent liver transplantation for HB in 3 major centers in Korea over 4 years. Eighty‐five patients (41.9%) had a hepatocellular carcinoma (HCC). Preoperative active virus replicators with the HBeAg(+) (46.8%) and/or hepatitis B virus DNA(+) (39.4%) were observed in 136 patients (67.0%). The HB prophylaxis consisted of either HBIG monotherapy (n = 95, HBIG group) or combination therapy with lamivudine (n = 108, combination group). HB recurrence was defined as the appearance of the HBsAg. The follow‐up period was 28.3 ± 13.1 months (mean ± SD). HB recurred in 21 patients (10.3%) after transplantation. The time from transplantation to recurrence was 16.3 ± 9.4 months. Pre‐LT DNA positivity was more prevalent in HBIG group (55.8%) than in the combination group (39.8%) (P = 0.015). However, the incidence of HB recurrence was similar in the HBIG (6.3%) and combination group (13.8%), as well as between the active replicators (12.5%) and nonreplicators (4.1%) (P < 0.05). There was a far higher incidence of HB recurrence in patients receiving corticosteroid pulse therapy (21.0% vs. 7.9%), patients who experienced HCC recurrence (31.3% vs. 8.6%), and patients receiving chemotherapy to prevent HCC recurrence (25.0% vs. 4.4%) (P < 0.05). The cumulative corticosteroid dose was higher in patients who experienced recurrence of HB (P = 0.002). Multivariable analysis confirmed the effect of the cumulative corticosteroid dose and chemotherapy to be risk factors. Liver transplantation for HB is safe, with low recurrence rates if adequate prophylaxis is used. However, the cumulative corticosteroid dose and the chemotherapy used for HCC were risk factors for HB recurrence, so careful monitoring for HB recurrence is needed in these patients. Liver Transpl 13:451–458, 2007.

Prolonged Cold Ischemic Time Is a Risk Factor for Biliary Strictures in Duct-to-Duct Biliary Reconstruction in Living Donor Liver Transplantation

Background. Duct-to-duct (DD) anastomosis is an accepted procedure for biliary reconstruction in living donor liver transplantation (LDLT). However, biliary complication rates in LDLT recipients have been reported to be as high as 20% to 30% or more. In this study, we examined various potential risk factors for biliary stricture (BS) that occurs in the context of DD reconstruction in a single-active transplant center. Methods. Enrolled in this study were adults who underwent their first LDLT with DD reconstruction between August 2002 and May 2007 (n=283). BSs were defined as anastomotic strictures that required interventions or operative procedures to be corrected. We reviewed retrospectively the medical records of recipients, including medical history, surgical procedures, and progress, and analyzed risk factors of BS with the Kaplan-Meier method. Results. BS occurred in 58 of the 283 recipients (20.5%). The mean follow-up period was 24.4 months posttransplant (SD=16.5). The univariate analysis revealed that recipient age (P=0.032), bile duct size (P=0.003), biliary reconstruction surgeon (P=0.023), perfusion solution (P=0.001), cold ischemic time (CIT) (P<0.001), and biliary leakage history (P<0.001) were significant risk factors. In the multivariable analysis, CIT (P=0.001), biliary leakage history (P=0.002), bile duct size (P=0.021), and recipient age (P=0.036) were significant risk factors for BS. And, a CIT cutoff value of 71 min was calculated using the minimum P value approach with correction by the Miller and Siegmund method (P=0.0186). Conclusions. In this study, prolonged CIT is identified as a risk factor for BS in DD biliary reconstruction in LDLT.

Outcome of donors with a remnant liver volume of less than 35% after right hepatectomy.

To overcome the barrier of size match, right lobe graft has been widely used in living donor liver transplantation (LDLT). We assessed donor outcome, with a focus on remnant liver volume (RLV) after right hepatectomy based on the experiences of 2 LDLT centers, as a means of guiding the establishment of safe RLV limits for donor right hepatectomy. Between January 2002 and December 2003, a consecutive 146 liver donors who underwent right hepatectomy with at least 12 months of follow‐up were enrolled in this study. Donors were grouped into 2 groups according to RLV: group 1 (n = 74), <35% (range, 26.9‐34.9) and group 2 (n = 72), ≥35% (35.0‐46.8). No donors died or suffered a life‐threatening complication. Mean peak serum postoperative aspartate aminotransferase (AST) and alanine aminotransferase (ALT) (IU/L) levels were 219.5 ± 79.9 and 231.5 ± 83.3 in group 1 and 210.3 ± 81.6 and 225.8 ± 93.0 in group 2 (P = 0.497 and 0.699), respectively. Mean peak serum total bilirubin (TB) (mg/dL) level in group 1 (3.4 ± 1.6) was higher than in group 2 (2.8 ± 1.4; P = 0.023). Overall 23 (15.8%) major morbidities, 10 in group 1 (13.5%) and 13 in group 2 (18.1%), occurred according to Claviens system (P = 0.939). These included bleeding (n = 3 in group 1 and n = 6 in group 2; P = 0.282), ileus (n = 3 and 1; P = 0.324), biliary leakage (n = 4 and 4; P = 0.968), and pneumonia (n = 0 and 2; P = 0.149). Minor morbidities were also comparable in the 2 groups. In conclusion, the outcome of donors with an RLV of <35% was not different from that of donors with an RLV of ≥35%, with the exception of transient cholestasis. Therefore, a remnant RLV of <35% does not appear to be a contraindication for right liver procurement in living donors. Liver Transpl 12:201–206, 2006.

HCC in Living Donor Liver Transplantation: Can We Expand the Milan Criteria?

Background: The tumor biology of hepatocellular carcinoma (HCC) affects recurrence after liver transplantation (LT), but most selection guidelines are based only on tumor size and number. The aim of the study is to evaluate the possibility of expanding the selection criteria in living donor LT (LDLT) without compromising patient survival by adding α-fetoprotein (AFP) in selection guideline. Methods: One hundred thirty-nine patients who received LDLT with the diagnosis of HCC and survived more than 3 months were enrolled. The operability was based on Milan criteria but LT beyond the criteria was performed when requested by the patients and/or the guardian after thorough explanation. Results: The median follow-up duration was 28 months. One-, three- and five-year survival rates were 92.2, 82.6, and 79.9%. There was no survival difference between patients within or beyond Milan (p = 0.76). Serum AFP level >400 ng/ml, tumor size >5 cm, and vascular invasion were significant on univariate analysis, but only vascular invasion was significant on multivariate analysis (p = 0.007). Patients with >3 tumor nodules had better survival compared to ≤3 nodules (p = 0.196). Patient selection using tumor size ≤5 cm and AFP ≤400 ng/ml without limitation of tumor numbers could expand patient selection and improve patient survival. Conclusion: Application of serum AFP level to selection of HCC for LT affords better patient selection criteria.

The hepatic regeneration power of mild steatotic grafts is not impaired in living‐donor liver transplantation

The aim of this study was to assess histologic changes in steatotic grafts, regenerative capacity, and the outcome of steatotic grafts in living‐donor liver transplantation (LDLT). Between September 2002 and February 2004, 55 cases of LDLT with a liver biopsy performed on the 10th postoperative day were enrolled. Patients were grouped according to the intraoperative histologic degree of macrovesicular steatosis (MaS) as follows: Group 1, <5% (n = 24); Group 2, 5 to 15% (n = 24); and Group 3, 15 to 30% (n = 7). The intraoperative microscopic findings and the findings on the 10th postoperative day were compared. Immunohistochemistry was performed using antibody of proliferating cell nuclear antigen (PCNA) and Ki‐67 to assess the regeneration power of grafts on the 10th postoperative day. The histologic degree of MaS on postoperative day 10 decreased from 5.22 ± 1.04% (mean ± standard deviation) to 2.17 ± 1.90 in Group 2 (P < .001) and from 21.4 ± 8.02 to 4.43 ± 2.70 in Group 3 (P = .003). The number of positively stained hepatocytes in 10 high power fields was 48.0 ± 17.1, 53.8 ± 14.4, and 51.5 ± 4.1 in each group by PCNA (P = .681), and 24.0 ± 14.0, 25.5 ± 11.8, and 21.6 ± 6.8 by Ki‐67 (P = .825), respectively. No primary graft nonfunction (PNF) or delayed graft function (DGF) occurred. Major complications were comparable among groups. In conclusion, in LDLT, steatosis disappeared immediately after transplantation and hepatic regeneration power was not impaired in grafts with less than 30% of MaS. Furthermore, a mildly steatotic graft did not increase the risk of graft dysfunction or morbidity in LDLT. (Liver Transpl 2005;11:210–217.)

Small Hepatocellular Carcinoma: Radiofrequency Ablation versus Nonanatomic Resection—Propensity Score Analyses of Long-term Outcomes

PURPOSE To compare radiofrequency (RF) ablation with nonanatomic resection (NAR) as first-line treatment in patients with a single Barcelona Clinic Liver Cancer (BCLC) stage 0 or A hepatocellular carcinoma (HCC) and to evaluate the long-term outcomes of both therapies. MATERIALS AND METHODS This retrospective study was approved by the institutional review board. The requirement for informed consent was waived. Data were reviewed from 580 patients with HCCs measuring 3 cm or smaller (BCLC stage 0 or A) who underwent ultrasonographically (US) guided percutaneous RF ablation (n = 438) or NAR (n = 142) as a first-line treatment. Local tumor progression, intrahepatic distant recurrence, disease-free survival, and overall survival rates were analyzed by using propensity score matching to compare therapeutic efficacy. In addition, major complications and length of postoperative hospital stay were compared. RESULTS Before propensity score matching (n = 580), the 5-year cumulative rates of local tumor progression for RF ablation and NAR (20.9% vs 12.7%, respectively; P = .093) and overall survival rates (85.5% vs 90.9%, respectively; P = .194) were comparable, while the 5-year cumulative intrahepatic distant recurrence rates (62.7% vs 36.6%, respectively; P < .001) and disease-free survival rates (31.7% vs 61.1%, respectively; P < .001) in the NAR group were significantly better than those in the RF ablation group. After matching (n = 198), there were no significant differences in therapeutic outcomes between the RF ablation and NAR groups, including 5-year cumulative intrahepatic distant recurrence (47.0% vs 40.2%, respectively; P = .240) and disease-free survival rates (48.9% vs 54.4%, respectively; P = .201). RF ablation was superior to NAR for major complication rates and length of postoperative hospital stay (P < .001). CONCLUSION In patients with one BCLC stage 0 or A (≤ 3 cm) HCC who received RF ablation or NAR as first-line treatment, there were no significant differences in long-term therapeutic outcomes; however, RF ablation was associated with fewer major complications and a shorter hospital stay after treatment.

Donor morbidity including biliary complications in living-donor liver transplantation: single-center analysis of 827 cases.

Background Because of the shortage of deceased-donor livers for transplantation, living-donor liver transplantation (LDLT) has become an indispensible treatment strategy for end-stage liver disease. The critical prerequisite for LDLT is the maximal safety of healthy donors. Methods From June 1996 to November 2010, a total of 827 completed donor hepatectomies were performed in our center. We analyzed donor morbidity associated with LDLT. Results There was no donor mortality. No complications were observed in 744 (90.0%) donors, and 83 (10.0%) donors experienced complications. Wound complications were most common, occurring in 48 (5.8%) patients. According to a modified Clavien classification, grade I, grade II, grade IIIa, and grade IIIb complications were experienced in 56 (67.5%), 2 (2.4%), 15 (18.1%), and 10 (12.0%) donors, respectively. Surgical or interventional management was successful in all grade IIIa and grade IIIb donors. The incidence of biliary complications was significantly higher in younger donors. Donor morbidity did not decrease below the attained level even after time had passed. Conclusions This study demonstrates the safety of donor hepatectomy. Complications were relatively minor and easily controlled. The incidence of biliary complications and donor age was inversely correlated. The procedural experience of the surgeons was not associated with the donor complication rate.