Frederick C. Ryckman

Genetic induction of proinflammatory immunity in children with biliary atresia

BACKGROUND Biliary atresia is the commonest cause of pathological jaundice in infants and the leading indication for liver transplantation in children worldwide. The cause and pathogenesis remain largely unknown. Because of clinical heterogeneity and experimental difficulties in addressing molecular mechanisms underlying multifactorial disorders in human beings, we searched for genomic signatures of biliary atresia in affected infants. METHODS We generated pools of biotinylated cRNA from livers of 14 infants with biliary atresia and six with neonatal intrahepatic cholestasis (diseased controls) and hybridised the cRNA against oligonucleotide-based gene chips. Immunohistochemistry and reverse transcriptase (RT)-PCR were used to assess the specificity of the findings and functional commitment of lymphocytes in affected livers. FINDINGS Data filtering, to identify genes that are differentially expressed, and cluster analysis revealed a predominant and coordinated activation of immunity/inflammation genes within the livers of infants with biliary atresia. Most of the genes showed differential lymphocyte function, with activation of osteopontin, a regulator of cell-mediated (T-helper 1 [Th-1]) immunity in T-helper lymphocytes, and suppression of immunoglobulin genes in early stages of disease. These findings were associated with production of interferon gamma in 65% of infants with biliary atresia and no diseased control. However, histologically similar inflammatory infiltrates were present in livers of both groups, implying differential activation states of similar cell types. INTERPRETATION Livers of infants with biliary atresia have a coordinated activation of genes involved in lymphocyte differentiation. Among these genes, the overexpression of osteopontin and interferon gamma points to a potential role of Th-1-like cytokines in disease pathogenesis.

Improved survival in biliary atresia patients in the present era of liver transplantation

Therapy for patients with biliary atresia (BA) has become controversial, with orthotopic liver transplantation (OLTx) suggested in place of portoenterostomy. This is based on the unpredictable success of portoenterostomy, and the increased difficulty of the OLTx procedure following prior extensive liver surgery. The survival rate reported here for infants transplanted after unsuccessful portoenterostomy does not support this approach. OLTx was undertaken in 37 patients when end-stage liver failure followed primary portoenterostomy. Recipient age ranged from 6 months to 14 years (median, 13 months), and weight ranged from 5 to 45 kg (median, 8 kg) at the time of OLTx. Reduced-size allografts were used as the primary allograft in 25 patients (23 left lobe), and 12 received whole-organ allografts. Retransplantation was required in 5 patients, each received a reduced-size allograft. There was no increased incidence of vascular complications, primary nonfunction, irreversible rejection, intestinal perforation, biliary complications, sepsis, or lymphoma comparing the BA patients with all other non-BA patients who had undergone OLTx (all P = .16). There was no statistically significant difference in mean operative blood loss between BA patients (EBL = 1.99 BV) and non-BA patients (1.50 BV) (P = .14). Actuarial survival for the series of BA patients was 89% at 1 year, and 80% at 2 years. Following the introduction of reduced-size allografts, donor organs were selected for use with a priority on donor stability. The actuarial survival for BA patients during this time has improved to 96% at 1 year, and 91% at 2 years.(ABSTRACT TRUNCATED AT 250 WORDS)

LONG-TERM SURVIVAL AFTER LIVER TRANSPLANTATION

BACKGROUND Liver transplantation (LT) remains a high-risk operation, especially during the first months after LT when technical complications and preexisting illness exert their influence on survival. However, there are late deaths. The authors have reviewed their experience to identify factors impacting on long-term survival. METHODS A total of 150 patients who had undergone liver transplantation over an 11-year period were reviewed. Thirty-three patients died after LT (22%). Of these, 18 of 33 (55%) died in the first 3 postoperative months. One hundred thirty-two patients survived beyond 3 months, and 15 patients (11%) suffered late deaths. This review concentrates on the latter group. RESULTS The primary cause of death was sepsis in 11 of 15 (73%). In two, sepsis complicated retransplantation in chronically debilitated patients. Two additional patients had late-presenting postoperative complications (bile leak or abscess, intestinal obstruction with perforation). In two cases, pneumocystis carinii pneumonia occurred; noncompliance or unplanned discontinuation of prophylaxis was directly responsible. Multiple organ system failure from presumed immunoincompetence developed in four patients; one had undergone bone marrow transplantation for aplastic anemia (AA) after fulminant hepatic failure (FHF). Lymphoproliferative disease (LPD) was the cause of death in 3 of 15 cases (20%). In only three cases was the cause of death related to the patients primary disease (chronic hepatitis, Alpers syndrome or seizures, and AA with FHF). Pretransplant diagnosis, and UNOS status at the time of LT did not influence the long-term survival. CONCLUSIONS Long-term survival in patients who have undergone LT was compromised by immunosuppressive complications and sepsis. Early mortality factors, such as UNOS status, age at LT, primary diagnosis, and technical complications do not predict late deaths. In children who adhere to their medical regimen and have good initial allograft function, late postoperative infection, especially with Ebstein-Barr virus, accounts for most of the late mortality. Improved and decreased immunosuppression may further improve these long-term results.

The spectrum of bile duct complications in pediatric liver transplantation

It has been noted that reduced-size liver transplants are associated with increased rates of biliary complications, and it has been suggested that some of these complications can be handled nonoperatively. In a 6-year period, 91 orthotopic liver transplants were performed in 77 children. The medical records were reviewed to analyze the effect of reduced-size grafts on the incidence of bile duct complications and to investigate the utility of interventional radiology techniques for treatment. Forty-two children received 47 whole-organ transplants, and 35 children received 44 reduced-size transplants. The median age and weight were greater for children receiving whole-organ transplants (age, 4.25 years; weight, 16 kg) than for those receiving reduced-size grafts (age, 1.0 year; weight, 8 kg). The overall incidence of bile duct complications was 19.5% (n = 15). The incidence was not different between the whole organ group (17%) and the reduced-size group (16%). Four of the children with bile duct complications had associated hepatic artery thrombosis, two of whom had another transplant. Complications included anastomotic stricture (n = 6), anastomotic leak (n = 5), intraparenchymal biloma (n = 3), and multiple strictures (n = 1). Twelve of 15 children presented within 3 months of transplantation. Six children had initial percutaneous drainage or placement of transanastomotic stents (external). Operative repair was eventually required for all 15 children, three of whom received a second transplant. There was a 40% incidence of cytomegalovirus infection involving the liver or extrahepatic bile ducts near the time of presentation.(ABSTRACT TRUNCATED AT 250 WORDS)

Pediatric burn patients with respiratory failure: Predictors of outcome with the use of extracorporeal life support

Extracorporeal life support (ECLS) for pediatric burn patients is a viable option for respiratory failure that is unresponsive to maximal conventional therapy. No criteria have been identified that are predictive of the success of the use of ECLS for these patients. This article presents a retrospective review of the pediatric burn patients placed on ECLS at a single pediatric medical center. It was found that 12 patients (mean age, 30.3 months; range 6 to 69 months) were placed on ECLS because of profound pulmonary failure that was unresponsive to aggressive ventilatory support. The mean size of the burns of these patients was 50.2% of the total body surface area (average size of full-thickness burns, 41.8% total body surface area), with 6 patients having scald burns and 6 having flame burns. The overall survival was 67% (8 of 12). Nonsurvivors had greater positive end-expiratory pressure, mean airway pressure, peak inspiratory pressure, and oxygenation index before ECLS. It is felt that ECLS is a life-saving therapy for pediatric patients with thermal injury. Greater ventilator requirements before ECLS are associated with nonsurvival. Early institution of ECLS in pediatric burn patients with severe respiratory failure may prevent excessive barotrauma and thus discourage the onset of irreversible lung injury.

Monoethylglycinexylide formation in assessing pediatric donor liver function.

Lidocaine metabolism to monoethylglycinexylide (MEGX) has been described as a novel method to assess liver function in adult transplant donors and recipients. While this assay appears to offer a number of advantages over existing liver function tests, limited work has been done to evaluate its potential in the pediatric population. This study evaluated MEGX formation in potential pediatric liver donors (n = 35) and a control group of children (n = 16). The mean MEGX formation was significantly higher in pediatric donors than in the control group (156 ± 62 vs 106 ± 33 ng/ml, p < 0.05). No correlation with age, total bilirubin, liver transaminases, or alkaline phosphatase could be made within each group. Significant differences in MEGX levels were noted when each group was compared to its adult counterpart. Both pediatric donors and controls had greater mean MEGX formation than has been reported for adult donors and controls (156 ± 62 vs 127 ± 61 ng/ml, p < 0.05 and 106 ± 33 vs 72 ± 36 ng/ml, p < 0.05, respectively). Drugs that alter lidocaine pharmacokinetics and their potential influence on MEGX formation were evaluated in the pediatric donor group. Donors exposed to hepatic enzyme-inducing drugs had a higher mean MEGX formation (187 ± 60 vs 146 ± 63 ng/ml). No significant differences were noted between donors receiving and not receiving va-sopressors. In conclusion, the significant differences between pediatric and adult MEGX formation should be noted when establishing reference or normal ranges for this diagnostic test. Furthermore, concomitant drug therapy may significantly alter MEGX formation.

Liver Disease in Children: Liver Transplantation in Children

Children with end-stage liver disease now have a greater chance of survival through treatment with hepatic transplantation. This article reviews the pediatric liver transplantation process, including selection and evaluation of candidates, operative procedures, postoperative complications, and long-term survival.