Influence of Hematopoietic Stem Cell-Derived Hepatocytes on Liver Regeneration after Sex-Mismatched Liver Transplantation in Humans

ABSTRACT

Background: Presence of hematopoietic stem-cell-derived hepatocytes after clinical liver transplantation was demonstrated repeatedly. The relevance of this controversial mechanism of regeneration was discussed. Regarding frequency, the demonstrated results were divergent. In the present study, we propose to investigate the influence of growth and regeneration on the frequency of hematopoietic stem-cell-derived hepatocytes in transplanted organs. Material and Method: Paraffin-embedded liver specimens, obtained as clinically indicated, from female grafts transplanted into male recipients were investigated. The presence of Y-chromosome in hepatocytes, detected by fluorescence in situ hybridization (FISH), was the indicator for recipient origin. Slides were evaluated by assessing the relative number of Y-chromosome containing hepatocytes within 50 images representing an average of 775 hepatocytes. Results: In only 9 out of 81 specimens, single Y-chromosome positive hepatocytes were detected, resulting in a maximal frequency of 0.64%. Six positive specimens were obtained from full-size liver grafts and one from a partial liver graft. In the pediatric group, two positive samples were found. By staining additional sections from the nine positive specimens, no additional positive hepatocytes were detected suggesting an even lower frequency within the whole sample. We did not find any accumulation of Y-chromosome positive cells in any of the individually analyzed patient groups. Conclusion: Transdifferentiation of hematopoietic stem cells is an extremely rare event in liver growth and regeneration after transplantation. Due to the low number of positive events, the biological relevance seems questionable.     

肝素结合的类表皮生长因子促进大鼠减体积肝移植术后移植肝细胞的再生

目的 探讨肝素结合的类表皮生长因子（heparin binding epidermal growth factor—like growth factor，HB-EGF）对大鼠减体积肝移植术后肝细胞再生的促进作用。方法 采用改良“二袖套法”建立大鼠原位减体积肝移植模型，分为实验组和对照组，术后即刻经尾静脉分别给予HB-EGF（500μg／kg）和相同体积的生理盐水，2次／d。2组分别在术后第6h、2d、4d及7d随机挑取5只大鼠处死，称取移植物湿重，采血检测血清丙氨酸转氨酶（ALT）及白蛋白（Alb），流式细胞仪检测移植肝细胞的增殖活性，免疫组织化学法检测移植肝Ki-67的表达情况。结果术后第6h、2d和4d，实验组移植物湿重较对照组相应时相明显增加（P〈0．05）；术后第6h、2d、4d和7d，实验组血清ALT水平较对照组相应时相明显降低（P〈0．05），而第4和7d时Alb水平较对照组相应时相明显增高（P〈0．05）；术后第2和4d时，实验组的移植肝细胞增殖指数和Ki-67表达较对照组高（2d：P〈0．01；4d：P〈0．05）。结论 大鼠原位减体积肝移植术后使用HB-EGF能够明显促进移植肝细胞的再生。     

大鼠肝移植后肝再生的实验研究

目的：探讨部分肝移植术后移植肝的再生问题。方法：建立大鼠部分肝移植模型，实验分为肝切除组（PLR组）、全肝移植组（OLT组）和部分肝移植组（POLT组）3组，分别于术后不同时间段取外周血检测总胆红素和谷丙转氨酶水平；取肝组织行组织学检查及流式细胞仪检测移植肝的增殖活性。结果：移植术后1w，肝功能酶学指标增高，后逐步降低；组织学检查术后可见单核细胞浸润，特别在门静脉周围汇管区，肝实质可见点状坏死。术后1个月可见胆管增殖；PLR组和POLT组还可见二倍体和多倍体的肝细胞，中央小静脉、肝窦和叶间静脉轻度扩张。PLR组和POLT组肝细胞增生活跃，3组分别于术后1d、2d、4d达到增殖高峰。结论：部分移植肝和肝切除后肝脏具有同样的增殖活性，但增殖高峰POLT组及OLT组均要晚于肝切除后的肝脏，但移植组增殖周期长。这可能是由于手术操作及肝脏缺血再灌注损伤所致。而持续时间长可能与受体免疫系统产生的细胞因子和激素的调控相关。     

Side-to-Side Cavocavostomy in Adult Piggyback Liver Transplantation

Objective

Our objective was to perform a retrospective study that described the anastomosis technique as well as the complications of side-to-side cavo-caval reconstruction.

Patients and Methods

From June 1998 to April 2011, we performed 284 liver transplantations including 10 adults with live donor organs. In all cases but 2 (272), cavo-caval reconstruction was performed using side-to-side cavo-caval (STSCC) anastomosis. In 19 cases (6.9%), we also carried out an end-to-side temporary porto-caval shunt (TPCS). In 17 cases (6.2%) the technique was performed for retransplantation.

Results

STSCC anastomosis was technically feasible in all but 2 cases, regardless of the recipient's vena cava, anatomic factors, or graft size. Mean operative time for the STSCC was 13 minutes (range, 6-25). Routine Doppler ultrasonography was performed intraoperatively at the end of the surgery. There was no case of cava stump thrombosis. Complications associated with this technique were limited to 2 patients. One complication was torsion due to donor graft/recipient mismatch, which was successfully treated surgically by falciform ligament fixation. The second complication was only evident by sinusoidal congestion and was managed nonoperatively. Seventeen cases were uneventful for retransplant recipients.

Conclusions

STSCC during piggyback liver transplantation is safe and can be performed in the retransplantation setting, with a low incidence of venous outflow obstruction that can be associated with the traditional piggyback technique. Our data suggest that donor graft to recipient mismatch is not an absolute contraindication when proper body size match is considered. A wide anastomosis with typical recipient hepatic vein inclusion is warranted with routine postanastomotic Doppler ultrasonography.     

Donor Outcomes After Liver Donation in Adult to Adult Living Donor Liver Transplantation

Objectives

This study aims to investigate postdonation outcomes of adult living donor liver transplantation donors and remnant liver regeneration in different graft types.

Graft Regeneration in Pediatric Living Donor Liver Transplantation

Objective

Due to the shortage of cadaver liver grafts in Asia, more than 90% of biliary atresia (BA) patients require living donor liver transplantation (LDLT), but the factors that influence liver graft regeneration in pediatric patients are still unclear. The aim of this study was to evaluate the potential predisposing factors that encourage liver graft regeneration in pediatric liver transplantation (LT).

Methods

Case notes and Doppler ultrasound and computed tomography studies performed before and 6 months after transplantation of 103 BA patients who underwent LDLT were reviewed. The predisposing factors that triggered liver regeneration were compiled from statistical analyses and included the following: age, gender, body weight and height, spleen size, graft weight–to–recipient weight ratio (GRWR), post-transplantation total portal flow, and vascular complications.

Results

Seventy-two pediatric recipients were enrolled in this study. The liver graft regeneration rate was 29.633 ± 36.61% (range, −29.53–126.27%). The size of the spleen (P = .001), post-transplantation portal flow (P = .004), and age (P = .04) were correlated lineally with the regeneration rate. The GRWR was negatively correlated with the regeneration rate (P = .001) and was the only independent factor that affected the regeneration rate. When the GRWR was >3.4, patients tended to have poor and negative graft regeneration (P = .01).

Conclusion

Large-for-size grafts have negative effect on regeneration rates because liver grafts that are too large can compromise total portal flow and increase vascular complications, especially when the GRWR is >3.4. Thus, optimal graft size is more essential than other factors in a pediatric LDLT patient.     

无心跳供肝大鼠肝移植模型的手术操作技巧探讨

目的建立一个稳定的无心跳供肝大鼠原位肝移植模型。方法在Kamada"二袖套法"的基础上进行改良,根据供肝获取前经历无心跳热缺血时间不同分为10min(R10组)、20min(R20组)和30min(R30组)3组,比较各组术后1周大鼠存活率。结果供体手术时间约30min(不含热缺血时间)。供肝冷保存时间均为1h。肝上下腔静脉吻合时间12～22min(平均15min),门静脉和肝下下腔静脉套管分别约需2min和1min。无肝期时间14～24min(平均19min),受体总手术时间50～65min(平均60min)。大鼠术后24h内死亡视为手术失败,共计12例死亡。R10组、R20组和R30组手术成功率分别为95%(19/20)、80%(16/20)和65%(13/20),术后1周生存率分别为95%(18/19)、81%(13/16)和54%(7/13)。结论在Kamada"二袖套法"基础上进行改良的大鼠无心跳供肝肝移植模型能很好地模拟临床无心跳供肝肝移植。大鼠肝脏能耐受30min以内的热缺血时间,移植术后短期存活结果满意,长期存活率尚需进一步研究。     

Bacterial Translocation in Adult Small Bowel Transplantation

The application of intestinal transplantation is limited by the high rate of infectious complications that can occur; the migration of enteric microorganisms to extraintestinal sites (bacterial translocation) has been suggested to be responsible for this event. We reviewed 95 intestinal biopsies performed on 28 transplanted patients to identify histologic features predictive of isolation of enteric microorganisms in extraintestinal sites within the first month after transplantation.At least 1 isolation of enteric microorganisms in the peritoneal cavity and/or in blood samples was obtained in 13 patients (46.4%); this event led to higher 1-year mortality (38.5% vs. 6.7%; P = .041). Of the 95 biopsies, 38 were followed by positive cultures (40.0%), showing higher degrees of mucosal vascular alterations (Ruiz grade) and ischemia/reperfusion injuries (Park/Chiu grade) compared with the negative cases (P < .05). We also observed an higher prevalence of positive cultures in relation to acute cellular rejection episodes (P = .091). Neither clinical or surgical factors nor immunosuppressive therapy were observed to be significantly related to positive cultures. Histologic alterations of the small bowel allograft are related to isolation of enteric microorganisms in extraintestinal sites. The degree of these histologic features can identify patients at high risk of potentially life-threatening infectious complications and death.     

Liver Regeneration and Splenic Enlargement in Donors after Living-Donor Liver Transplantation

Liver regeneration after donor hepactectomy offers a unique insight into the process of liver regeneration in normal livers. As the liver restores itself, concurrent splenic enlargement occurs. There are many theories about why this phenomenon takes place: some investigators have proposed a relative portal hypertension that leads to splenic congestion or, perhaps, the presence of a common growth factor that induces both the liver and spleen to enlarge. Between the months of June 2001 and May 2004, 112 live donor liver transplants (LDLTs) were performed in Chang Gung Memorial Hospital, Kaohsiung, Taiwan. The total number of donor hepatectomies performed during this period was 113, however, because one of the cases required dual donors. Of our 113 donors, we eventually analyzed the data of 109; 4 patients were lost to follow-up 6 months later and were excluded from our study. The average age of our donor population was 32.32 ± 8.48 years. The mean liver volume at donation was noted to be 1207.72 ± 219.95 cm³, and 6 months later, it was 1027.18 ± 202.41 cm³. Expressed as a percentage of the original volume, the mean liver volume 6 months after hepatectomy was 90.70% ± 12.47% in this series. For right graft donors, mean liver volume after 6 months was 89.68% ± 12.37% of the original liver volume, whereas that for left graft donors was 91.99% ± 12.6%. Only 26 of the 109 (23.85%) donors were able to achieve full regeneration 6 months post-donation. Notably, liver function profiles of all donors were normal when measured 6 months after operation. The average splenic volume at donation as measured by computed tomography (CT) volumetry was 159 ± 58 cm³, and the splenic volume 6 months post-donation was 213 ± 85 cm³. There was a mean increment in splenic volume of 35% ± 28% 6 months after donation. The blood profiles of the donors were monitored; particular attention was given to platelet levels and liver function tests, and these were found to be within normal limits 6 months after operation. Of note, splenic enlargement was significantly greater among right-sided donors than their left-sided counterparts. Greater splenic enlargement was also observed in those donors who achieved full liver regeneration at their evaluation 6 months postoperatively than in those who did not. Although original liver volume was not re-established in most patients 6 months after liver donation, there seemed to have been no untoward effects to the donor. The factors that affect liver regeneration are complex and myriad. Although there is splenic enlargement at 6 months post-donation in donors of LDLT, there are no untoward effects of this enlargement.     

Initial Clinical Effect of Intraportal Insulin Administration on Liver Graft Regeneration in Adult Patients Underwent Living Donor Right Lobe Liver Transplantation

ObjectiveInsulin is one factor responsible for hepatotrophic regeneration in animal models. This study assessed the clinical effects of intraportal administration of insulin on liver graft regeneration in adult patients undergoing right lobe living donor liver transplantation (LDLT).MethodsBetween July 2005 and September 2007, 19 right lobe LDLT adult recipients voluntarily received posttransplant intraportal insulin administration. The present study describes 15 patients without postoperative vascular and bile duct complications, with more than 1 month survival and with complete clinical data who were enrolled to receive intraportal insulin therapy (group I; n = 15). Another consecutive 15 right lobe LDLT adult recipients without any stimulation regeneration who met the same criteria were enrolled in as noninsulin therapy control group (group NI; n = 15). Group I recipients were treated postoperatively with intraportal insulin infusion, as follows. An 18-gauge catheter was inserted into right gastro-omental vein during surgery, to administer regular insulin just after the operation at the rate of 2 U/h for 1 week. Graft volume (GV) was measured by computed tomography on postoperative days (POD) 7 and 30. Liver functions and serum insulin levels were also measured at POD 7 and POD 30. The liver graft regeneration rate was defined as ratio of posttransplant GV/harvested GV and posttransplant graft-to-recipient weight ratio (GRWR)/operative GRWR.ResultsThe rate defined as ratio of POD 7 GV/harvested GV among group I was significantly greater than that of group NI (186.07 ± 35.40% vs 160.61 ± 22.11%; P < .05). The rate defined as ratio of POD 7 GRWR/operation GRWR was also significantly higher in group I than group NI (178.95 ± 35.84% vs 156.56 ± 18.53%; P < .05), whereas there was no significant difference in terms of regeneration rates at 1 month post-LDLT. Intraportal insulin administration may significantly downregulate POD 7 total bilirubin, aspartate aminotransferase, and alanine aminotransferase levels (P < .05). These results suggested that intraportal insulin administration augmented liver regeneration during the first postoperative week by improving hepatic function in LDLT recipients.     

Regeneration Rate of Left Liver Grafts in Adult Living Donor Liver Transplant

Objective

Appropriate graft weight is important in liver transplant to provide better graft regeneration and to avoid small-for-size syndrome with graft failure. Generally, to protect the donor, the left liver is always selected as the graft. The aim of this study is to evaluate the regeneration rate of the left lobe liver graft in adult living donor liver transplantation (ALDLT).

Patients and Methods

The records and preoperative and postoperative images within 6 months after liver transplantation were reviewed for 9 left and 145 right liver grafts ALDLT enrolled in this study. We calculated the graft volume at 6 months after transplantation divided by the standard liver volume as the regeneration ratio. The regeneration rate of the group with a left liver graft ALDLT was compared with our right liver graft group.

Results

The liver graft regeneration ratio of the left lobe was 85.3 ± 11.0 (range, 61-97), slightly lower than the right liver graft (91.2 ± 12.6%; range, 58-151). In the graft-recipient body weight ratio (GRWR) > 1, the regenerative rate was slightly higher than the group of GRWR < 1. The regeneration ratio was proportional to spleen volume and portal inflow (P = .039).

Conclusion

Either the right or left liver graft can achieve sufficient regeneration in ALDLT. However, there was a slightly lower regeneration rate among the left liver graft and GRWR < 1 groups. Spleen size, a major factor contributing to portal inflow, may directly trigger graft regeneration after transplantation with a linear correlation in growth.     

Incisional Hernia in Recipients of Adult to Adult Living Donor Liver Transplantation

Background

After receiving a living donor liver transplant (LDLT), an incisional hernia is a potentially serious complication that can affect the patient’s quality of life. In the present study we evaluated surgical hernia repair after LDLT.

Materials and methods

Medical records of patients who underwent surgery to repair an incisional hernia after LDLT in Turgut Ozal Medical Center between October 2006 and January 2010 were evaluated in this retrospective study. A reverse-T incision was made for liver transplantation. The hernias were repaired with onlay polypropylene mesh. Age, gender, post-transplant relaparatomy, the type, the result of surgery for the incisional hernia, and risk factors for developing incisional hernia were evaluated.

Results

An incisional hernia developed in 44 of 173 (25.4 %) patients after LDLT. Incisional hernia repair was performed in 14 of 173 patients (8.1 %) who underwent LDLT from October 2006 to January 2010. Relaparatomy was associated with incisional hernia (p = 0.0002). The mean age at the time of the incisional hernia repair was 51 years, and 79 % of the patients were men. The median follow-up period was 19.2 (13–36) months after the hernia repair. Three patients with intestinal incarceration underwent emergency surgery to repair the hernia. Partial small bowel resection was required in one patient. Postoperative complications included seroma formation in one patient and wound infection in another. There was no recurrence of hernia during the follow-up period.

Conclusions

The incidence of incisional hernia after LDLT was 25.4 % in this study. Relaparatomy increases the probability of developing incisional hernia in recipients of LDLT. According to the results of the study, repair of an incisional hernia with onlay mesh is a suitable option.     

Portal Venous Pressure in Adult Living Donor Liver Transplantation

Objective

The relationship between portal pressure and small-for-size syndrome (SFSS) is unsettled. The purpose of this study was to evaluate the role of portal pressure in predicting SFSS.

Methods

Thirty-four patients with end-stage liver disease who received adult-to-adult living-donor liver transplantation (ALDLT) were included. Recipients were grouped based on whether they received portal flow modulation or not. The intraoperative portal vein flow volume (PVFV) and portal venous pressure (PVP) between the 2 groups were compared. The relationship of PVP to PVFV, graft weight-to-recipient weight ratio (GRWR), and graft weight-to-recipient spleen size ratio (GRSSR) were analyzed.

Results

Persistent portal hypertension was found after ALDLT. The PVP was linearly correlated with PVFV but not with GRWR or GRSSR. With the use of the following criteria, (1) PVFV >250 mL/min/100 g graft weight, (2) GRWR <0.8%, and (3) GRSSR <0.6, modulation of the portal flow was performed in 3 cases. The receiver operating characteristic analysis showed that 23 mm Hg was the cutoff point for PVP, with a sensitivity of 83% and specificity of 43%.

Conclusions

PVP is a weak parameter to use for portal flow modulation after ALDLT. It is sensitive but not specific to predict SFSS.     

Biliary Internal Stents and Biliary Complications in Adult Liver Transplantation

BackgroundBiliary complications in liver transplantation (LT) can cause significant morbidity or even lead to a potential graft loss and patient mortality. Oftentimes biliary internal stents (ISs) are used at the time of LT to lower the risk for or prevent these biliary complications; however, their efficacy and outcomes remain controversial.MethodsA retrospective cohort study was conducted on all of the adult patients who underwent a deceased-donor LT (DDLT) with an end-to-end choledococholedocostomy. An IS was placed across the biliary anastomosis, passing through the ampulla. We compared the demographic profiles and various outcomes between the 2 groups (no-IS group vs IS group) and examined risk factors associated with anastomotic biliary complications.ResultsThe study comprised 350 patients in the no-IS group and 132 patients in the IS group. Anastomotic biliary fistula (ABF) occurred in 5 (1.4%) and 1 (0.8%) patients in the no-IS group and the IS group, respectively (P = .55). Anastomotic biliary stricture (ABS) occurred in 53 (15.1%) and 18 (13.6%) patients, respectively (P = .68). No significant difference was found in the overall biliary complications between the 2 groups (P = .33). In multivariate logistic regression analysis, acute rejection was the only risk factor for ABS (P = .02). One biliary complication–induced mortality occurred in the no-IS group in which the patient died of an ABF-induced hepatic artery pseudoaneurysm rupture.ConclusionThe use of biliary ISs in DDLT did not reduce the overall risk for biliary complications, but more research is needed to draw definite conclusions.     

Platelet Transfusion can be Related to Liver Regeneration After Living Donor Liver Transplantation

Background  

Although liver regeneration is a fundamental aspect of living donor liver transplantation (LDLT), the factors that affect liver regeneration during the early post-transplantation period have not been thoroughly investigated. Recently it was suggested that platelets contribute to liver regeneration. The aim of the present study was to identify the major factors that affect liver graft regeneration during the early post-transplantation period.     

成人活体部分肝移植的临床抉择

目的 探讨成人活体部分肝移植中供肝移植物大小与术式的临床抉择。方法 采用文献回顾的方法对活体部分肝移植中供体的评估、供肝大小的判断与选择、切取术式，以及供体安全性等加以综述。结果 供肝移植物大小是影响供体安全性与受体预后的关键因索，临床有带肝中静脉的左半肝移植、含左侧尾叶的扩大左半肝移植、右半肝移植以及带肝中静脉的扩大右半肝移植可供选择，以使供肝与受体标准肝大小之比(GW／ESLW)≥30％，供肝与受体体重之比(GW／BW)≥0.8％。结论 根据GW／ESLW以及GW／BW预测值．结合肝脏解剖特点．选择合理的供肝切除术是具有重要的临床意义。     

Does Liver Transplantation in the Rat Cause a Regenerative Response

This study was conducted to determine the pattern of early regenerative response to orthotopic intact liver transplantation in the rat and to investigate whether the response differed in grafts with or without revascularisation of the arterial bed.Outbred male Long Evans (LE-LE allogeneic, non rejector) rats weighing 300–350g were subjected to orthotopic intact liver allograft using a “sleeve” anastomosis for the hepatic artery. Total warm ischaemia ranged from 19 to 34 minutes and no storage was employed. Comparison was made with a group of control rats which were subjected to 25 minutes total inflow occlusion and regeneration was measured with tissue thymidine kinase (TK) and mitotic figures. Samples were taken at 1,2,4,7,10 and 20 days post-operatively. Plasma aspartate aminotransferase (AAT) and light microscopy were used to evaluate hepatocyte necrosis. There was a brief sharp increase in TK and AAT in the first 24 hours after sham operation but no appearance of mitotic figures. A similar but more prolonged increase in TK occurred in the arterialised transplant group with the highest levels recorded on day 4. The level remained significantly elevated above pre-operative until 10 days and declined within 20 days. Mitotic figures appeared at 2 days, reached significance at 7 and 10 days and had disappeared by 20 days. The pattern of changes was accentuated in animals in which the artery was not reanastomosed and the increases in TK and AAT were still significant at 20 days. Whilst similar degrees of peri-portal cellular infiltrate occurred in both groups of rats, bile duct proliferation was most obvious in non-arterialised animals.As compared with a previously prepared group of partially hepatectomised animals, the regenerative response after liver transplant was delayed and prolonged especially in the non-arterialised group.It is concluded that a regenerative response occurred in liver allografts in rats soon after operation, which was slightly prolonged if the hepatic artery was not anastomosed and that the response seemed to be related to hepatocyte damage which occurred as part of the procedure. The relevance of these findings to clinical liver transplantation is discussed.     

大鼠小肠移植模型的改进

目的：在传统小肠移植模型基础上改进操作方法并试图建立一个操作简便、并发症少、稳定的大鼠小肠移植模型.方法：显微镜下切取供肠的范围包括近端空肠、门静脉及其带肠系膜上动脉的腹主动脉袖.动脉吻合采用供体带肠系膜上动脉的腹主动脉袖与受体的腹主动脉端侧吻合,静脉吻合采用供体的门静脉用袖套法与左肾静脉端端吻合,移植肠两端造瘘.结果：正式实验100次,手术成功率91%.供体手术控制在50 min以内,受体手术控制在80 min以内,手术时间约为150 min.结论：完全在显微镜下建立大鼠小肠移植模型并将手术方法加以改进能在手术视野清晰、术中操作定位准确、局部创伤小的基础上使手术时间缩短,并发症更少,存活率更高.