Small for size syndrome following living donor and split liver transplantation

Small-for-size syndrome in a 9.7 kg pediatric recipient with a whole liver graft

BACKGROUND

Small-for-size syndrome (SFSS) in pediatric liver transplant recipients, particularly those weighing less than 10 kg, is rare. This report describes a case of a 15-month-old whole liver transplant recipient who suffered SFSS, and systematic literature review was performed to identify outcomes of such cases and potential risk factors for SFSS.

CASE PRESENTATION

A 15-month-old toddler with a history of biliary atresia underwent a deceased donor whole liver transplant. The graft weighed 160 g, resulting in a graft-to-recipient weight ratio (GRWR) of 1.6%. The post-operative course was complicated by SFSS, characterized by massive ascites causing hemodynamic instability and compromised hepatic artery flow. Pharmacological intervention with octreotide was initiated, and the patient eventually recovered.

CONCLUSION

In small pediatric recipients, especially those weighing less than 10 kg, the native liver body weight ratio (LBWR) is significantly higher. When selecting an appropriately sized graft for these recipients, this higher ratio should be taken into consideration. The literature review suggests that a GRWR of less than 2% is associated with a higher incidence of small-for-size syndrome in small pediatric recipients weighing less than 10 kg.

Association between Hepatocellular Carcinoma Recurrence and Graft Size in Living Donor Liver Transplantation: A Systematic Review

The aim of this work was to assess the association between graft-to-recipient weight ratio (GRWR) in adult-to-adult living donor liver transplantation (LDLT) and hepatocellular carcinoma (HCC) recurrence. A search of the MEDLINE and EMBASE databases was performed until December 2022 for studies comparing different GRWRs in the prognosis of HCC recipients in LDLT. Data were pooled to evaluate 1- and 3-year survival rates. We identified three studies, including a total of 782 patients (168 GRWR < 0.8 vs. 614 GRWR ≥ 0.8%). The pooled overall survival was 85% and 77% at one year and 90% and 83% at three years for GRWR < 0.8 and GRWR ≥ 0.8, respectively. The largest series found that, in patients within Milan criteria, the GRWR was not associated with lower oncological outcomes. However, patients with HCC outside the Milan criteria with a GRWR < 0.8% had lower survival and higher tumor recurrence rates. The GRWR < 0.8% appears to be associated with lower survival rates in HCC recipients, particularly for candidates with tumors outside established HCC criteria. Although the data are scarce, the results of this study suggest that considering the individual GRWR not only as risk factor for small-for-size-syndrome but also as contributor to HCC recurrence in patients undergoing LDLT would be beneficial. Novel perfusion technologies and pharmacological interventions may contribute to improving outcomes.

Portal modulation effects of terlipressin on liver regeneration and survival in a porcine model subjected to 90% hepatectomy

BACKGROUND

Excessive postoperative portal pressure is associated with post-hepatectomy liver failure and small-for-size syndrome after partial liver transplantation. This study aimed to identify the portal modulation effects of terlipressin on liver regeneration and survival in a porcine model subjected to 90% hepatectomy.

METHODS

Twenty pigs undergoing 90% hepatectomy were divided into control (n = 10) and terlipressin (n = 10) groups. Terlipressin 0.5 mg was injected subcutaneously three times a day, from immediately before hepatectomy to 7 days after surgery, for surviving pigs in the terlipressin group. Portal pressure measurement, biochemical analysis, assessment of molecular markers for liver regeneration, and immunohistochemistry were performed in both groups.

RESULTS

The 7-day survival rate was significantly higher in the terlipressin group than that in the control group. Portal pressure in the terlipressin group was lower than that in the control group at 30 min and 1 h after hepatectomy. Total bilirubin level was lower in the terlipressin group than that in the control group at 1 h and 6 h after hepatectomy. Proliferating cell nuclear antigen expression was higher in the control group than that in the terlipressin group at 6 h after hepatectomy, while the proportion of Ki-67-positive cells was higher in the terlipressin group than that in the control group at 7 days after hepatectomy. Endothelin-1 level reflecting liver injury was lower in the terlipressin group than that in the control group at 1 h and 6 h after hepatectomy.

CONCLUSION

Terlipressin could optimize liver regeneration and improve survival through rapid and effective portal modulation after extensive hepatectomy.

New Insights Into the Role of Autophagy in Liver Surgery in the Setting of Metabolic Syndrome and Related Diseases

Visceral obesity is an important component of metabolic syndrome, a cluster of diseases that also includes diabetes and insulin resistance. A combination of these metabolic disorders damages liver function, which manifests as non-alcoholic fatty liver disease (NAFLD). NAFLD is a common cause of abnormal liver function, and numerous studies have established the enormously deleterious role of hepatic steatosis in ischemia-reperfusion (I/R) injury that inevitably occurs in both liver resection and transplantation. Thus, steatotic livers exhibit a higher frequency of post-surgical complications after hepatectomy, and using liver grafts from donors with NAFLD is associated with an increased risk of post-surgical morbidity and mortality in the recipient. Diabetes, another MetS-related metabolic disorder, also worsens hepatic I/R injury, and similar to NAFLD, diabetes is associated with a poor prognosis after liver surgery. Due to the large increase in the prevalence of MetS, NAFLD, and diabetes, their association is frequent in the population and therefore, in patients requiring liver resection and in potential liver graft donors. This scenario requires advancement in therapies to improve postoperative results in patients suffering from metabolic diseases and undergoing liver surgery; and in this sense, the bases for designing therapeutic strategies are in-depth knowledge about the molecular signaling pathways underlying the effects of MetS-related diseases and I/R injury on liver tissue. A common denominator in all these diseases is autophagy. In fact, in the context of obesity, autophagy is profoundly diminished in hepatocytes and alters mitochondrial functions in the liver. In insulin resistance conditions, there is a suppression of autophagy in the liver, which is associated with the accumulation of lipids, being this is a risk factor for NAFLD. Also, oxidative stress occurring in hepatic I/R injury promotes autophagy. The present review aims to shed some light on the role of autophagy in livers undergoing surgery and also suffering from metabolic diseases, which may lead to the discovery of effective therapeutic targets that could be translated from laboratory to clinical practice, to improve postoperative results of liver surgeries when performed in the presence of one or more metabolic diseases.

The beneficial impacts of splanchnic vasoactive agents on hepatic functional recovery in massive hepatectomy porcine model

Background

Excessive portal pressure after massive hepatectomy can cause hepatic sinusoidal injury and have deleterious impacts on hepatic functional recovery, contributing to developing post-hepatectomy liver failure. This study aimed to assess the effects of splanchnic vasoactive agents on hepatic functional recovery and regeneration while clarifying the underlying mechanism, using a 70% hepatectomy porcine model.

Methods

Eighteen pigs undergoing 70% hepatectomy were involved in this study and divided into three groups: control (n=6), terlipressin (n=6), and octreotide (n=6). Terlipressin (0.5 mg) and octreotide (0.2 mg) were administered 3 times a day for each group with the first dose starting just before surgery until the 7th postoperative day, at which time the surviving pigs were sacrificed. During the period, portal pressure, liver weight, biochemical analysis, histological injury score, and molecular markers were evaluated and compared between groups.

Results

The 7-day survival rates in the octreotide, terlipressin, and control groups were 100%, 83.3%, and 66.7%, respectively. The portal pressures decreased in both terlipressin and octreotide groups than the control group at 30 minutes, 1 hour and 6 hours after hepatectomy. The amount of regeneration measured by liver weight to body weight ratio at the time of sacrifice in the terlipressin group was smaller than that in the control group (117% vs. 129%, P=0.03). Serum aspartate aminotransferase (AST) and total bilirubin levels at 1 and 6 hours after hepatectomy and prothrombin time/international normalized ratio (PT/INR) at 6 hours after hepatectomy were significantly improved in the terlipressin and octreotide groups compared to the control group. Serum endothelin-1 (ET-1) was significantly lower in the terlipressin group than that in the control group 6 hours after hepatectomy (P<0.01). The histological injury score in the control group was significantly higher than that in the terlipressin group on the 7th postoperative day (P<0.01).

Conclusions

Splanchnic vasoactive agents, such as terlipressin and octreotide, could effectively decrease portal pressure and attenuate liver injury after massive hepatectomy.

Long-Term Outcomes of Abdominal Wall Reconstruction with Expanded Polytetrafluoroethylene Mesh in Pediatric Liver Transplantation

Background: Large-for-size syndrome caused by organ size mismatch increases the risk of abdominal compartment syndrome. Massive transfusion and portal vein clamping during liver transplantation may cause abdominal compartment syndrome (ACS) related to mesenteric congestion. In general pediatric surgery—such as correcting gastroschisis—abdominal wall reconstruction for the reparation of defects using expanded polytetrafluoroethylene is an established method. The purpose of this study is to describe the ePTFE-Gore-Tex closure method in patients with or at a high risk of ACS among pediatric liver transplant patients and to investigate the long-term prognosis and outcomes. Methods: From March 1988 to March 2018, 253 pediatric liver transplantation were performed in Seoul National University Hospital. We retrospectively reviewed the cases that underwent abdominal wall reconstruction with ePTFE during liver transplantation. Results: A total of 15 cases underwent abdominal closure with ePTFE-GoreTex graft. We usually used a 2 mm × 10 cm × 15 cm sized Gore-Tex graft for extending the abdominal cavity. The median follow up was 59.5 (17–128.7) months and there were no cases of ACS after transplantation. There were no infectious complications related to ePTFE implantation. The patient and graft survival rate during the study period was 93.3% (14/15). Conclusions: Abdominal wall reconstruction using ePTFE is feasible and could be an alternative option for patients with a high risk of ACS.

Frequency of whole-organ in lieu of split-liver transplantation over the last decade: Children experienced increased wait time and death

Organ shortage is a barrier to liver transplantation (LT). Split LT (SLT) increases organ utilization, saving 2 recipients. A simulation of Organ Procurement and Transplantation Network/United Network for Organ Sharing data (2007-2017) was performed to identify whole-organ LT grafts (WLT) that met the criteria for being splittable to 2 recipients. Waitlist consequences presented. Deceased donor (DD) livers transplanted as whole organs were evaluated for suitability to split. Of these DD organs, we identified the adolescent and adult recipients of WLT who were suitable for SLT. Pediatric candidates suitable to share the SLT were ascertained from DD match-run lists, and 1342 splittable DD organs were identified; 438 WLT recipients met the criteria for accepting a SLT. Review of the 438 DD match-run lists identified 420 children next on the list suitable for SLT. Three hundred thirty-three children (79%) underwent LT, but had longer wait-times compared to 591 actual pediatric SLT recipients (median 147 days vs 44 days, P  < 0.001). Thirty-three of 420 children died on waitlist after a mean 206 days (standard deviation 317). Sharing organs suitable for splitting increases the number of LT, saving more lives. With careful patient selection, SLT will not be a disadvantage to the adult recipients. With a children-first allocation scheme, SLT will naturally increase the number of allografts because adult organs are too large for small children.

Postoperative Portal Hypertension Enhances Alloimmune Responses after Living-Donor Liver Transplantation in Patients and in a Mouse Model

Controlling portal vein pressure in living-donor liver transplantation has received increased attention owing to its potential importance for graft survival. Portal hypertension may lead to the activation of liver-resident APCs, including liver sinusoidal endothelial cells (LSECs), which have immunological tolerogenic capacity. We investigated the effects of portal hypertension on graft survival and the antidonor immune response using clinical data and a mouse model. We categorized patients (n = 136) according to their portal vein pressure values at the end of surgery. Using propensity score-matching analyses, we found that portal hypertension was significantly associated with a higher antidonor immune response and incidence of acute rejection. To investigate the mechanism, we performed an allogeneic coculture assay using a 70% hepatectomized (HTx) mouse model with or without a portosystemic shunt. Liver cells from HTx mice without a shunt exhibited a significantly greater anti-BALB/c B6 T cell response than those from sham-operated mice or HTx mice with a shunt. LSECs from sham-operated mice, but not from HTx mice, suppressed the B6 T cell alloresponse in a dose-dependent manner. Furthermore, LSECs from HTx mice without a shunt showed significantly downregulated MHC class I/II and programmed death-ligand 1 expression, and those from mice with a shunt showed recovered expression of these molecules. Postoperative portal hypertension enhances alloimmune responses in recipients after living-donor liver transplantation, likely due, in part, to the impaired immune-suppression capacity of LSECs.

A national mandatory-split liver policy: A report from the Italian experience

To implement split liver transplantation (SLT) a mandatory-split policy has been adopted in Italy since August 2015: donors aged 18-50 years at standard risk are offered for SLT, resulting in a left-lateral segment (LLS) graft for children and an extended-right graft (ERG) for adults. We aim to analyze the impact of the new mandatory-split policy on liver transplantation (LT)-waiting list and SLT outcomes, compared to old allocation policy. Between August 2015 and December 2016 out of 413 potentially "splittable" donors, 252 (61%) were proposed for SLT, of whom 53 (21%) donors were accepted for SLT whereas 101 (40.1%) were excluded because of donor characteristics and 98 (38.9%) for absence of suitable pediatric recipients. The SLT rate augmented from 6% to 8.4%. Children undergoing SLT increased from 49.3% to 65.8% (P = .009) and the pediatric LT-waiting list time dropped (229 [10-2121] vs 80 [12-2503] days [P = .045]). The pediatric (4.5% vs 2.5% [P = .398]) and adult (9.7% to 5.2% [P < .001]) LT-waiting list mortality reduced; SLT outcomes remained stable. Retransplantation (HR = 2.641, P = .035) and recipient weight >20 kg (HR = 5.113, P = .048) in LLS, and ischemic time >8 hours (HR = 2.475, P = .048) in ERG were identified as predictors of graft failure. A national mandatory-split policy maximizes the SLT donor resources, whose selection criteria can be safely expanded, providing favorable impact on the pediatric LT-waiting list and priority for adult sick LT candidates.

Effects of splanchnic vasoconstrictors on liver regeneration and survival after 90% rat hepatectomy

Purpose

Posthepatectomy liver failure is a serious complication and considered to be caused by increased portal pressure and flow. Splanchnic vasoactive agents and propranolol are known to decrease portal pressure. The aim of this study was to identify optimal candidates with potential for clinical use among somatostatin, terlipressin, and propranolol using rats with 90% hepatectomy.

Methods

Rats were divided into 5 groups: sham operation (n = 6), control (n = 20), propranolol (n = 20), somatostatin (n = 20), and terlipressin group (n = 20). Seven-day survival rates and portal pressure change were measured, and biochemical, histologic, and molecular analyses were performed.

Results

Portal pressure was significantly decreased in all 3 treatment groups compared to control. All treatment groups showed a tendency of decreased liver injury markers, and somatostatin showed the most prominent effect at 24 hours postoperatively. Histologic liver injury at 24 hours was significantly decreased in propranolol and terlipressin groups (P = 0.016, respectively) and somatostatin group showed borderline significance (P = 0.056). Hepatocyte proliferation was significantly increased after 24 hours in all treatment groups. Median survival was significantly increased in terlipressin group compared to control group (P < 0.01).

Conclusion

Terlipressin is considered as the best candidate, while somatostatin has good potential for clinical use, considering their effects on portal pressure and subsequent decrease in liver injury and increase in liver regeneration.

Adipose-derived mesenchymal stem cells promote liver regeneration and suppress rejection in small-for-size liver allograft

Adipose-derived mesenchymal stem cells (ADSCs) possess a liver regeneration capacity and immunosuppressive activity and hold promise in autologous cell-based technology. This study aimed to determine whether autologous ADSCs can improve outcomes in the rat reduced size liver transplantation model. Allogeneic 50% orthotopic liver transplantation followed by administration of autologous ADSCs delivered into the portal vein system was conducted in LEW donor rats and BN recipient rats with phosphate buffered solution (PBS) infusion used as the control. Liver grafts and recipient serum were obtained. We assessed histopathology, regeneration, apoptosis, serum liver enzymes, serum cytokines, and circulating regulatory T cells (Tregs) on postoperative day (POD) 7 and 14. It was found that ADSCs significantly reduced acute rejection and improved the allograft's survival times (median, 24days). Liver function, as assessed by the levels of alanine aminotransferase, aspartate aminotransferase, total bilirubin, as well as liver apoptosis was significantly alleviated in the ADSC group compared with the control group. In addition, ADSC therapy markedly promoted the expression of PCNA in the allograft. Furthermore, levels of interleukin (IL)-10 and transforming growth factor (TGF)-β1 were significantly elevated, whereas those of IL-2 and IL-17 levels were significantly reduced in the ADSC group when compared to the control group. Moreover, flow cytometry analysis revealed that peripheral Tregs had been significantly increased by the infusion of ADSCs. These results demonstrate that implanted autologous ADSCs improve allogeneic reduced size liver allograft outcomes by attenuating acute rejection and reducing inflammatory responses, as well as enhancing liver regeneration.

Patterns of Early Allograft Dysfunction in Adult Live Donor Liver Transplantation: The A2ALL Experience

BACKGROUND

Early allograft dysfunction (EAD) after living donor liver transplantation (LDLT) has often been attributed to inadequate graft size, and termed small-for-size syndrome. Early allograft dysfunction definitions include a variable constellation of findings, including hyperbilirubinemia, coagulopathy, encephalopathy, and ascites formation. Among putative causes of EAD after LDLT are excessive portal pressure and/or flow. Our objective was to evaluate patterns of EAD after LDLT.

METHODS

In this study, 631 LDLT recipients were monitored for complications, EAD (defined by postoperative day 7 bilirubin >10 mg/dL or international normalized ratio >1.6), and graft failure. Approximately 200 had portal venous and arterial pressure and flow measurements before and after LDLT. Portal inflow modification (splenic artery ligation, hemiportocaval shunt, or splenectomy) was performed at the discretion of the operating surgeon. Associations between EAD and recipient, donor, and transplant factors were examined using multivariable logistic regression.

RESULTS

Risk of EAD was associated with left lobe grafts, lower graft weight among left lobes, higher preoperative bilirubin, higher portal reperfusion pressure, higher donor age, and higher donor body mass index. The risk of graft loss within the first 90 days was 5.2 times higher for recipients with EAD versus those without EAD (P < 0.001).

CONCLUSIONS

Early allograft dysfunction can be defined using postoperative day 7 laboratory values that are highly predictive of early graft failure within 90 days. Risk factors associated with EAD after LDLT include: graft type and size, preoperative bilirubin, portal reperfusion pressure, donor age, and donor body mass index.

Is size the only determinant of delayed abdominal closure in pediatric liver transplant?

The aim was to determine the factors associated with the use of delayed abdominal closure in pediatric liver transplantation (LT) and whether this affected outcome. From a prospectively maintained database, transplants performed in children (≤18 years) were identified (October 2010 to March 2015). Primary abdominal closure was defined as mass closure performed at time of transplant. Delayed abdominal closure was defined as mass closure not initially performed at the same time as transplant; 230 children underwent LT. Of these, 176 (76.5%) had primary closure. Age was similar between the primary and delayed groups (5.0 ± 4.9 versus 3.9 ± 5.0 years; P = 0.13). There was no difference in the graft-to-recipient weight ratio (GRWR) in the primary and delayed groups (3.4 ± 2.8 versus 4.1 ± 2.1; P = 0.12). Children with acute liver failure (ALF) were more likely to experience delayed closure then those with chronic liver disease (CLD; P < 0.001). GRWR was similar between the ALF and CLD (3.4 ± 2.4 versus 3.6 ± 2.7; P = 0.68). Primary closure children had a shorter hospital stay (P < 0.001), spent fewer days in pediatric intensive care unit (PICU; P = 0.001), and required a shorter duration of ventilation (P < 0.001). Vascular complications (arterial and venous) were similar (primary 8.2% versus delayed 5.6%; P = 0.52). Graft (P = 0.42) and child survival (P = 0.65) in the primary and delayed groups were similar. Considering timing of mass closure after transplant, patients in the early delayed closure group (<6 weeks) were found to experience a shorter time of ventilation (P = 0.03) and in PICU (P = 0.003). In conclusion, ALF was the main determinant of delayed abdominal closure rather than GRWR. The optimal time for delayed closure is within 6 weeks. The use of delayed abdominal closure does not adversely affect graft/child survival. Liver Transplantation 23 352-360 2017 AASLD.

Small-for-size syndrome in live donor liver transplantation-Pathways of injury and therapeutic strategies

Due to the severe organ shortage and the increasing gap between the supply and demand for donor grafts, live donor liver transplantation (LDLT) has become an accepted and alternative technique for the expansion of the donor pool. However, donor safety and good recipient outcomes must be balanced regarding risk stratification and decision-making within this patient population. Small-for-size syndrome (SFSS) is one of the complications encountered after LDLT, thus increasing the burden of optimizing donor graft selection and effective treatments during its occurrence. A graft-to-recipient weight ratio (GRWR) <0.8 predisposes the graft to SFSS. However, other factors may induce this complication even without a graft-to-patient size mismatch. Several strategies to prevent this complication include portal vein flow and liver outflow modulation, as well as pharmacological treatment. Also, as an entity with a multifactorial etiology, outcomes vary between right-lobe, left-lobe, and posterior-lobe donation among series encountered in the literature. In this review, we analyze the pathophysiology and classification of this complication, the state-of-the-art on management of SFSS, and the outcomes regarding the best treatment strategy on this patient population.

Using on-site liver 3-D reconstruction and volumetric calculations in split liver transplantation

BACKGROUND

Split liver transplantation increases the number of grafts available for transplantation. Pre-recovery assessment of liver graft volume is essential for selecting suitable recipients. The purpose of this study was to determine the ability and feasibility of constructing a 3-D model to aid in surgical planning and to predict graft weight prior to an in situ division of the donor liver.

METHODS

Over 11 months, 3-D volumetric reconstruction of 4 deceased donors was performed using Pathfinder Scout© liver volumetric software. Demographic, laboratory, operative, perioperative and survival data for these patients along with donor demographic data were collected prospectively and analyzed retrospectively.

RESULTS

The average predicted weight of the grafts from the adult donors obtained from an in situ split procedure were 1130 g (930-1458 g) for the extended right lobe donors and 312 g (222-396 g) for left lateral segment grafts. Actual adult graft weight was 92% of the predicted weight for both the extended right grafts and the left lateral segment grafts. The predicted and actual graft weights for the pediatric donors were 176 g and 210 g for the left lateral segment grafts and 308 g and 280 g for the extended right lobe grafts, respectively. All grafts were transplanted except for the right lobe from the pediatric donors due to the small graft weight.

CONCLUSIONS

On-site volumetric assessment of donors provides useful information for the planning of an in situ split and for selection of recipients. This information may expand the donor pool to recipients previously felt to be unsuitable due to donor and/or recipient weight.

Stem Cell Therapies for Treatment of Liver Disease

Cell therapy is an emerging form of treatment for several liver diseases, but is limited by the availability of donor livers. Stem cells hold promise as an alternative to the use of primary hepatocytes. We performed an exhaustive review of the literature, with a focus on the latest studies involving the use of stem cells for the treatment of liver disease. Stem cells can be harvested from a number of sources, or can be generated from somatic cells to create induced pluripotent stem cells (iPSCs). Different cell lines have been used experimentally to support liver function and treat inherited metabolic disorders, acute liver failure, cirrhosis, liver cancer, and small-for-size liver transplantations. Cell-based therapeutics may involve gene therapy, cell transplantation, bioartificial liver devices, or bioengineered organs. Research in this field is still very active. Stem cell therapy may, in the future, be used as a bridge to either liver transplantation or endogenous liver regeneration, but efficient differentiation and production protocols must be developed and safety must be demonstrated before it can be applied to clinical practice.

Split liver transplantation: What’s unique?

The intraoperative management of split liver transplantation (SLT) has some unique features as compared to routine whole liver transplantations. Only the liver has this special ability to regenerate that confers benefits in survival and quality of life for two instead of one by splitting livers. Primary graft dysfunction may result from small for size syndrome. Graft weight to recipient body weight ratio is significant for both trisegmental and hemiliver grafts. Intraoperative surgical techniques aim to reduce portal hyperperfusion and decrease venous portal pressure. Ischemic preconditioning can be instituted to protect against ischemic reperfusion injury which impacts graft regeneration. Advancement of the technique of SLT is essential as use of split cadaveric grafts expands the donor pool and potentially has an excellent future.

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.

[Hospital-based multicenter study in Spain, Mexico and Cuba on attitudes to living liver donation]

INTRODUCTION

Given the lack of a sufficient number of livers available for transplantation, living liver donation (LLD) is being developed in the Spanish-speaking world. To do this, it is essential that health workers in hospitals are in favor of such donation, given that they are a key component in this treatment and that their attitudes influence public opinion.

OBJECTIVE

To analyze attitude toward LLD among hospital personnel from healthcare centers in Spain and Latin America.

MATERIAL AND METHOD

Ten hospitals were selected from the «International Donor Collaborative Project»: 3 from Spain, 5 from Mexico and 2 from Cuba. Random sampling stratified by type of service and job category was used. Attitudes to LLD were evaluated through a validated questionnaire on psychosocial aspects. The questionnaire was anonymous and self-administered. Statistical tests consisted of Student's T test, the chi-square test and logistic regression analysis.

RESULTS

Of the 2,618 employees surveyed, 85% (n=2,231) were in favor of related LLD; of these, 31% (n=804) were in favor of unrelated LLD. No association was found between the country of the interviewed, personal-social variables or work-related variables. The following factors were associated with a favorable attitude toward related LLD donation: having had personal experience of donation and transplantation (P<.001); being in favor of deceased donation (P<.001); believing that one might need a possible transplant (P<.001); being in favor of living kidney donation (P<.001); being willing to accept a liver from a living donor (P<.001); having discussed the matter of donation and transplantation within the family (P<.001) and with one's partner (P<.001); carrying out pro-social type activities (P<.001); being Catholic (P=.040); believing that one's religion is in favor of donation and transplantation (P<.001); and not being concerned about the possible mutilation of the body after donation (P<.001).

CONCLUSIONS

Hospital personnel from Spain and Latin America had a favorable attitude toward LLD, which was associated with factors directly and indirectly related to donation and transplantation, family and religious factors, and attitudes toward the body.

Current issues in pediatric liver transplantation

Pediatric patients with ESLD requiring liver transplantation often have a multitude of comorbidities ranging from pulmonary hypertension to renal and cardiovascular insufficiency that impairs our ability to safely care for these critically ill children. As organ allocation techniques advance, many of these patients may be healthier on arrival to the operating room. However, postoperative surgical complications and immunosuppressive regimens still daunt us. As we continue to care for these challenging patients, hopefully, advances in ESLD management and technology will dramatically improve outcomes in the future.

SOD mimetic improves the function, growth, and survival of small-size liver grafts after transplantation in rats

BACKGROUND

Small-for-size syndrome (SFSS) may occur when graft volume is less than 45% of the standard liver volume, and it manifests as retarded growth and failure of the grafts and more mortality. However, its pathogenesis is poorly understood, and few effective interventions have been attempted.

AIMS

The present study aimed to delineate the critical role of oxidant stress in SFSS and protective effects of a superoxide dismutase mimetic, Mn(III)tetrakis(4-benzoic acid)porphyrin chloride (MnTBAP), on graft function, growth, and survival in the recipient rats.

METHODS

Small size graft liver transplantation (SSGLT) was performed to determine the survival, graft injury, and growth. MnTBAP was administered in SSGLT recipients (SSGLT+MnTBAP).

RESULTS

Serum alanine aminotransferase levels were sustained higher in SSGLT recipients, which were correlated with an increased apoptotic cell count and hepatocellular necrosis in liver sections. Malondialdehyde content, gene expression of tumor necrosis factor α and interleukin 1β, and DNA binding activity of nuclear factor-κB in the grafts were increased significantly in SSGLT recipients compared with sham-operated controls. Both phosphorylated p38 mitogen-activated protein kinase and nuclear c-Jun were increased in SSGLT. All these changes were strikingly reversed by the administration of MnTBAP, with an increase in serum superoxide dismutase activity. Moreover, in situ bromodeoxyuridine incorporation demonstrated that graft regeneration was much more profound in the SSGLT+MnTBAP group than in the SSGLT group. Finally, the survival of recipients with MnTBAP treatments was significantly improved.

CONCLUSIONS

Enhanced oxidant stress with activation of the p38/c-Jun/nuclear factor-κB signaling pathway contributes to SFSS-associated graft failure, retarded graft growth, and poor survival. MnTBAP effectively reversed the pathologic changes in SFSS-associated graft failure.

Modeling the hepatic arterial buffer response in the liver

In this paper we present an electrical analog model for the hepatic arterial buffer response (HABR), an intrinsic regulation mechanism in the liver whereby the arterial flow counteracts the changes in portal venous flow. The model itself is a substantial simplification of a previously published model, with nonlinear arterial and portal resistors introduced to account for the dynamic HABR effects. We calibrate the baseline model using published hemodynamic data, and then perform a virtual portal occlusion simulation where the portal vein is half or fully occluded. The simulation results, which suggest that the increased arterial flow cannot fully compensate lost portal perfusion, are consistent with clinical reports and animal model findings. Since HABR functions in both the whole liver and liver graft after transplantation, we also simulate blood flow in a virtual right-lobe graft by adjusting the electronic component parameters in the electric circuit, and our model is able to reproduce the portal venous hyperperfusion and hepatic arterial hypoperfusion conditions due to the HABR effects.

[Attitudes among Spanish and Latin American non-medical health professionals to living donor liver transplantation]

INTRODUCTION

Hospital professionals are an opinion group that influences the general population.

OBJECTIVE

To analyze attitudes to living donor liver transplantation (LDLT) among non-medical professionals working in Spanish and Latin American hospitals and to determine the variables that influence these attitudes.

MATERIAL AND METHOD

A random sample, stratified by department, was selected from non-medical staff in the "International Donor Collaborative Project": there were three hospitals in Spain, five in Mexico and two in Cuba. Attitudes were evaluated through a validated, anonymous, self-administered questionnaire.

RESULTS

There were 951 non-medical professionals: 277 from Spain, 632 from Mexico and 42 from Cuba. A total of 86% (n = 818) were in favor of related living donation and 31% (n = 299) were in favor of unrelated living donation. This attitude was associated with the following: country (Mexico 88%, Cuba 83%, Spain 81%) (p =0.016), female sex (p =0.026), having experience of donation and transplantation (p =0.001), having a favorable attitude to donation (P <0.001), considering the possibility of needing a transplant (P <0.001), being in favor of living kidney donation (P <0.001), being willing to accept a transplant from a living donor if necessary (P <0.001), discussing donation and transplantation with the family and partner (P <0.001), carrying out pro-social activities (P <0.001), believing that one's religion was in favor of donation and transplantation (P<0.001), and not worrying about bodily mutilation after donation (P <0.001).

CONCLUSIONS

Attitudes toward related LDLT among non-medical staff in various Spanish, Mexican and Cuban hospitals are favorable. In 86% of those surveyed, this attitude was not influenced by classical psychosocial factors.

Amphiregulin stimulates liver regeneration after small-for-size mouse liver transplantation

This study investigated whether amphiregulin (AR), a ligand of the epidermal growth factor receptor (EGFR), improves liver regeneration after small-for-size liver transplantation. Livers of male C57BL/6 mice were reduced to ~50% and ~30% of original sizes and transplanted. After transplantation, AR and AR mRNA increased in 50% but not in 30% grafts. 5-Bromodeoxyuridine (BrdU) labeling, proliferating cell nuclear antigen (PCNA) expression and mitotic index increased substantially in 50% but not 30% grafts. Hyperbilirubinemia and hypoalbuminemia occurred and survival decreased after transplantation of 30% but not 50% grafts. AR neutralizing antibody blunted regeneration in 50% grafts whereas AR injection (5 μg/mouse, iv) stimulated liver regeneration, improved liver function and increased survival after transplantation of 30% grafts. Phosphorylation of EGFR and its downstream signaling molecules Akt, mTOR, p70S6K, ERK and JNK increased markedly in 50% but not 30% grafts. AR stimulated EGFR phosphorylation and its downstream signaling pathways. EGFR inhibitor PD153035 suppressed regeneration of 50% grafts and largely abrogated stimulation of regeneration of 30% grafts by AR. AR also increased cyclin D1 and cyclin E expression in 30% grafts. Together, liver regeneration is suppressed in small-for-size grafts, as least in part, due to decreased AR formation. AR supplementation could be a promising therapy to stimulate regeneration of partial liver grafts.

"Left at right" adult liver transplantation: the feasibility of heterotopic implantation of left liver graft

Left liver grafts have been widely utilized in adult liver transplantation (LT) and yielded acceptable results. However, the conventional orthotopic implantation of a left liver graft imposes the potential risk of perioperative vascular complications. We report herein an alternative modified technique for adult left liver LT and evaluate its feasibility in LT. In this study, 10 recipients had their left liver graft rotated 180°, and heterotopically implanted at the right subphrenic space, which we termed "left at right" liver transplantation (LAR-LT). The sequence of vascular and biliary reconstruction was performed as standard techniques, and no perioperative vascular complications related to LAR-LT were encountered. There were two mortalities in this series, one due to a small-for-size graft dysfunction and the other due to postoperative internal hemorrhage. Two recipients had biliary strictures that were successfully managed by percutaneous biliary dilatation and Roux-en-Y hepaticojejunostomy. The clinical characteristics and outcomes of patients undergoing LAR-LT were also compared with patients undergoing conventional orthotopic left liver LT (n = 14). Although the results showed no significant difference between the two groups, according to our experience, the satisfactory outcome and easier technical reconstruction suggest that the LAR-LT modification could be a feasible alternative to left liver LT.

Hepatic flow optimization in full right split liver transplantation

Split liver transplantation for two adults offers a valuable opportunity to expand the donor pool for adult recipients. However, its application is mainly hampered by the physiological limits of these partial grafts. Small for size syndrome is a major concern during transplantation with partial graft and different techniques have been developed in living donor liver transplantation to prevent the graft dysfunction. Herein, we report the first application of synergic approaches to optimise the hepatic hemodynamic in a split liver graft for two adults. A Caucasian woman underwent liver transplantation for alcoholic cirrhosis (MELD 21) with a full right liver graft (S5-S8) without middle hepatic vein. Minor and accessory inferior hepatic veins were preserved by splitting the vena cava; V5 and V8 were anastomosed with a donor venous iliac patch. After implantation, a 16G catheter was advanced in the main portal trunk. Inflow modulation was achieved by splenic artery ligation. Intraportal infusion of PGE1 was started intraoperatively and discontinued after 5 d. Graft function was immediate with normalization of liver test after 7 d. Nineteen months after transplantation, liver function is normal and graft volume is 110% of the recipient standard liver volume. Optimisation of the venous outflow, inflow modulation and intraportal infusion of PGE1 may represent a valuable synergic strategy to prevent the graft dysfunction and it may increase the safety of split liver graft for two adults.

Role of living donor liver transplantation in the treatment of hepatitis C virus infection

Hepatitis C virus (HCV) infection is one of the most common indications for liver transplantation worldwide. Because of the existing organ shortage, adult-to-adult living donor liver transplantation (LDLT) has become an important method of expanding the donor pool to meet the ever-increasing need. However, despite advantages such as the quality of the hepatic graft and the timing of the transplant, the exact role of LDLT in the treatment of HCV is still unclear. In this review, we aim to address some of these issues in an effort to highlight both the advantages and disadvantages, as well as to identify the main challenges, of using LDLT for treating patients with HCV infection.