Liver retransplantation in children: the Atlanta experience.

Liver retransplantation is routinely offered at our institution. Previous reports document that patient and graft survival is significantly less after pediatric rLT compared to primary LT. This has engendered intense debate regarding optimal allocation of organs. Here, we examine our program's approach to pediatric hepatic retransplantation related to patient factors affecting outcomes. Between 1997 and 2009, 272 LTs were performed in 234 patients (mean survival 1994 +/- 1367 days) at our center. Thirty-four patients required rLT including 10 who received their primary transplant elsewhere and four who required two retransplantations. Patient survival did not differ significantly between rLT and LT at one and three yr (p = 0.56). Graft survival between rLT and LT was also similar (p = 0.606) at one and three yr. No significant difference in graft or patient survival was noted between: Patients retransplanted <30 days after LT vs. those >30 days (p = 0.152); patients transplanted with technical variants vs. whole grafts (p = 0.966); technical variants utilized for LT vs. rLT (p = 0.713); rLT recipient age (< or >5 yr; p = 0.298); or ABOI for rLT and LT (p = 0.650). Retransplantation should be offered to optimize pediatric recipient survival after LT and offers similar survival as primary transplant.

Incidence, impact, and treatment of portal and hepatic venous complications following pediatric liver transplantation: a single-center 12 year experience.

PVT or PVS and HVOO are known causes of graft and patient loss after pediatric liver transplantation. Increased incidences of these complications have been reported in partial livers including DDSLT or LDLT. From 1997 to 2008, 241 consecutive pediatric patients received 271 hepatic grafts at a single center. Median follow-up is 1856 days. Surgical technique, demographics, lab values, and radiologic imaging procedures were obtained utilizing OTTR to evaluate the relationship of portal and hepatic complications with risk factors, patient and graft survival. Grafts were composed of 115/271 (42.4%) partial livers of which 90 (33.2%) were DDSLT and 25 (9.2%) LDLT. Of 271 patients, 156 (57.6%) received whole-sized grafts. There were six PVC in five patients with one patient requiring retransplantation (0.34%) and no patient deaths. Utilizing all three hepatic vein orifices on the recipient hepatic vena cava and the donor hepatic vein cut short enables a wide hepatic outflow tract unlikely to twist. None of the 241 patients developed early or late complications of the hepatic vein. None of the last 128 consecutive patients who received 144 grafts over seven and a half yr have developed either early or late complications of the hepatic or portal vein. Partial-graft actuarial survival was similar to whole-graft survival (87.2% vs. 85.3% at one yr; 76.6% vs. 80.2 at three yr; p = 0.488). Likewise, patient survival was similar between partial grafts and whole grafts (93.8% vs. 93.1% at one yr; 89.8% vs. 87.2% at three yr; p = 0.688) with median follow-up of 1822 (+/-1334) days. Patients receiving partial livers were significantly younger and smaller than patients receiving whole livers (p < 0.001). Portal and hepatic venous complications may have negative effects on patient or graft survival after pediatric liver transplantation. In our series, there was one graft and no patient loss related to portal or hepatic venous complications after pediatric liver transplantation over 12 yr.

Pediatric liver transplantation for acute liver failure at a single center: a 10-yr experience.

Children transplanted for ALF urgently require an optimal graft and have lower post-transplant survival compared with children transplanted for chronic liver disease. Over 10 yr, 33 consecutive children transplanted for ALF were followed. Demographics, encephalopathy, intubation, dialysis, laboratory values, graft type ABOI, XL (GRWR > 5%), DDSLT, LDLT and WLT were evaluated. Complications and survival were determined. ALF accounted for 33/201 (16.4%) of transplants during this period. Twelve of 33 received ABOI, five XL grafts, 18 DDSLT, and three LDLT. Waiting time pretransplant was 2.1 days. One- and three-yr patient survival in the ALF group was 93.4% and 88.9%, and graft survivals were 86.4% and 77.7%. Median follow-up was 1452 days. ABOI one- and three yr patient and graft survival in the ALF was 91.6% and 78.6%. No difference in graft or patient survival was noted in the ALF and chronic liver disease group or the ABOI and the ABO compatible group. A combination of ABO incompatible donor livers, XL grafts, DDSLT, LDLT and WLT led to a short wait time and subsequent graft and patient survival comparable to patients with non-acute disease.

Successful outcome after early combined liver and en bloc-kidney transplant in an infant with primary hyperoxaluria type 1: a case report.

PH1 is a metabolic disorder characterized by urolithiasis and the accumulation of oxalate crystals in the kidneys and other organs. Although patients often first present with renal failure, PH1 results from a deficiency of the hepatic peroxisomal enzyme AGT. Ultimately only liver transplantation will cure the underlying metabolic defect. Herein, we report the case of a three-month-old male infant diagnosed with PH and treated using a combined liver and en bloc-kidney transplant from a single donor. At the time of transplant, the patient was 11 months old and weighed 7.9 kg. He received a full size liver graft and en bloc kidneys from a two-yr-old donor. At 36 months post-transplant, the patient is steadily growing with normal renal and hepatic function. This is one of the first reports of successful liver and en bloc-kidney transplantation with abdominal compartment expansion by PTFE for the infantile form of PH1 in a high risk child before one yr of age. Prompt diagnosis and early referral to a specialized center for liver and kidney replacement offer the best chance for survival for infants with this otherwise fatal disease.

Resistance to combined ganciclovir and foscarnet therapy in a liver transplant recipient with possible dual-strain cytomegalovirus coinfection.

We present a case report of a cytomegalovirus (CMV)-seronegative, 58-year-old male who received a CMV-seropositive donor liver transplant without CMV prophylaxis. On postoperative day 30, the patient developed primary CMV disease that responded to ganciclovir. On postoperative day 114, however, he was diagnosed with recurrent CMV infection. Despite aggressive, combined antiviral treatment with ganciclovir and foscarnet and reduction of immunosuppression, viral clearance was never achieved. Serum samples were collected throughout the infectious process for viral DNA analysis. Portions of the UL97 and UL54 genes were amplified and compared to the AD169 wild-type strain. Sequencing studies revealed the presence of mutations in viral isolates obtained after clinical resistance was observed. These mutations were not present in samples obtained during the primary CMV infection. Our findings suggest the presence of coinfection with at least 2 different strains of CMV rather than induction of mutations after ganciclovir therapy.

Involvement of p38 MAPK in the up-regulation of tissue factor on endothelial cells by antiphospholipid antibodies.

OBJECTIVE: To study the intracellular mechanism involved in the up-regulation of tissue factor (TF) on endothelial cells (ECs) by antiphospholipid antibodies (aPL), we examined the effects of aPL on the transcription, expression, and function of TF, the expression of interleukin-6 (IL-6) and IL-8, the induction of inducible nitric oxide synthase (iNOS), and the phosphorylation of p38 MAPK on human umbilical vein ECs (HUVECs). METHODS: Cultured HUVECs were treated with IgG aPL (from patients with antiphospholipid syndrome [APS]) or with control IgG (from normal human serum). Phorbol myristate acetate (PMA) and bacterial lipopolysaccharide (LPS) were used as positive controls. TF expression was determined on the surface of HUVECs using an enzyme-linked immunosorbent assay (ELISA). TF activity was determined with the use of a chromogenic assay in cell lysates, and TF messenger RNA (mRNA) was determined by real-time quantitative polymerase chain reaction. Phosphorylation of p38 MAPK and induction of iNOS were determined by Western blotting, and levels of IL-6 and IL-8 were determined by ELISA. RESULTS: PMA, LPS, and aPL significantly increased the expression of TF compared with controls. This up-regulation was significantly inhibited by SB203580 (a specific inhibitor of p38 MAPK) and by MG132 (a specific inhibitor of NF-kappaB). TF activity was significantly increased by treatment with IgG aPL and this effect was also inhibited by SB203580. Incubation of HUVECs with aPL increased TF mRNA 2-15-fold; these effects were abrogated by SB203580. IgG aPL induced significant phosphorylation of p38 MAPK and produced iNOS on HUVECs in a time-dependent manner. Treatment with IgG aPL also induced increased expression of IL-6 and IL-8 on HUVECs. CONCLUSION: Our data show that aPL induces significant increases in TF transcription, function, and expression, in IL-6 and IL-8 up-regulation, and in iNOS expression on HUVECs and that these processes involve phosphorylation of p38 MAPK and activation of NF-kappaB. Understanding intracellular events in aPL-mediated EC activation may help in designing new targeted therapies for thrombosis in APS.

Tuberous sclerosis-associated neoplasms express activated p42/44 mitogen-activated protein (MAP) kinase, and inhibition of MAP kinase signaling results in decreased in vivo tumor growth.

PURPOSE: Tuberous sclerosis (TS) is a common autosomal disorder attributable to inactivation of the tumor suppressor genes tuberin and hamartin. To determine whether mitogen-activated protein (MAP) kinase signaling plays a role in the pathogenesis of TS, we stained human TS-associated neoplasms with antibodies directed against activated MAP kinase, and observed high-level expression. EXPERIMENTAL DESIGN: To determine whether MAP kinase is functionally important for the development of neoplasia in TS, we established a murine model of TS-associated neoplasia (Tsc2Ang1 cells) from a tumor arising in a mouse heterozygous for tuberin. Tsc2Ang1 cells demonstrate tumorigenesis in vivo and high-level expression of activated MAP kinase in vitro. The functionality of MAP kinase signaling was assessed by inactivating MAP kinase using a dominant-negative MAP kinase kinase in tsc2ang1 cells and assessing the effect of this intervention on in vivo tumorigenicity and production of the potent angiogenic factor vascular endothelial growth factor (VEGF). RESULTS: Human TS-related neoplasms demonstrate high-level expression of activated MAP kinase, as does a tumor arising in a mouse heterozygous for tuberin. The inhibition of MAP kinase signaling by the introduction of a dominant-negative MAP kinase kinase leads to the inhibition of tumor growth in vivo and decreased production of VEGF. CONCLUSIONS: MAP kinase is activated in TS-related neoplasia in mice and humans. Inhibition of MAP kinase leads to decreased tumor growth in vivo. Pharmacological inhibition of MAP kinase may be a therapeutic target in the prevention and treatment of TS-related tumors.

Iron chelators inhibit VCAM-1 expression in human dermal microvascular endothelial cells.

Vascular cell adhesion molecule (VCAM)-1 expression may be coupled to redox-sensitive regulatory pathways, and iron may play a role in generation of reactive oxygen species that participate in these signaling pathways. To investigate the role of iron in TNF alpha-induced VCAM-1 gene expression, human dermal microvascular endothelial cells (HDMEC) were stimulated with TNF alpha in the presence of iron chelators and examined for expression of VCAM-1. The iron chelators dipyridyl (DP) and desferoxamine (DFO) inhibited VCAM-1 protein and mRNA induction in a concentration- and time-dependent manner. The induction of VCAM-1 was not inhibited by nonmetal binding reactive oxygen species (ROS) scavengers, implying a direct effect of iron in the expression of these adhesion molecules. The effect of iron was mediated at the level of gene transcription since pretreatment with DP abrogated the TNF alpha-mediated up-regulation of VCAM-1 heterogeneous nuclear RNA. Pretreatment of HDMEC with DP prior to TNFalpha treatment had no effect on p65 nuclear localization, DNA binding, or serine phosphorylation. DP pretreatment inhibited TNF alpha- and IFN gamma-mediated interferon regulatory factor 1 (IRF-1) protein expression, although restoration of IRF-1 expression failed to reconstitute VCAM-1 expression. DP treatment also blocked VCAM-1 induction in human umbilical vein endothelium and blocked induction of a host of NF-kB activated genes in HDMEC including ICAM-1, IL-8, and tissue factor. I kappa B alpha, an NF-kappa B inducible and constitutively accessible gene not requiring chromatin remodeling for transcription, was not affected by DP treatment. These data suggest that iron plays a critical role in TNF alpha mediated VCAM-1 induction in HDMEC, and the target for iron effects may be IRF-1, NF-kappa B, and potentially chromatin remodeling.

Regulation of tissue factor in microvascular dermal endothelial cells.

Inflammation is accompanied by activation of the coagulation cascade, manifested by thrombosis and fibrin generation. Whereas endothelial cells normally provide a nonthrombogenic surface, inflammatory mediators may induce the expression of tissue factor, rendering their surface thrombogenic. In order to define the mechanisms regulating the expression of tissue factor in the skin microvasculature, we examined tissue factor expression in human dermal microvascular endothelial cells. Quiescent human dermal microvascular endothelial cells did not constitutively express tissue factor protein, but were induced to express tissue factor by treatment with tumor necrosis factor-alpha in a time- and concentration-dependent fashion. Increased expression of tissue factor protein was accompanied by increases in steady-state mRNA levels. Tumor necrosis factor-alpha treatment resulted in increased expression of tissue factor heterogeneous nuclear RNA without changes in mRNA stability, suggesting that increased mRNA was mediated primarily via increased tissue factor gene transcription. In order to define the pathways regulating tissue factor induction, we examined the effects of MG-132, an inhibitor of nuclear factor-kappaB activation, PD98059, an inhibitor of MEK1 action, and SB203580, an inhibitor of activated p38 activity. MG132 only partially blocked tumor necrosis factor-alpha-induced tissue factor protein expression, despite an almost complete inhibition of tumor necrosis factor-alpha-induced E-selectin expression. In contrast, SB203580, almost completely inhibited tumor necrosis factor-alpha-induced tissue factor expression but inhibition of MEK1 by PD98059 had a minimal effect on tumor necrosis factor-alpha-mediated tissue factor induction in human dermal microvascular endothelial cells. Both SB203580 and MG132 treatment inhibited tumor necrosis factor-alpha-mediated increases in tissue factor mRNA and tissue factor gene transcription as measured by expression of tissue factor heterogeneous nuclear RNA. These data support a transcriptional role for both nuclear factor-kappaB and p38 mitogen-activated protein kinase, but not MEK1 in tissue factor gene expression in human dermal microvascular endothelial cells.

Induction of interferon regulatory factor 1 expression in human dermal endothelial cells by interferon-gamma and tumor necrosis factor-alpha is transcriptionally regulated and requires iron.

Interferon regulatory factor-1 is a transcription factor that is linked to the expression of genes important in the initiation of the inflammatory response and the control of cell cycle. In this study, we determined that the generation of interferon regulatory factor-1 expression in human dermal microvascular endothelial cells was transcriptionally mediated by tumor necrosis factor-alpha or interferon-gamma via iron-dependent pathways. The induction of interferon regulatory factor-1 protein and the up-regulation of interferon regulatory factor-1 mRNA levels was inhibited when cells were pretreated with the iron chelators 2-2-dipyridyl or deferoxamine. This inhibition of interferon regulatory factor-1 expression was associated with loss of interferon regulatory factor-1 binding to the interferon-stimulated response element as assessed by electrophoretic mobility shift assay. Addition of exogenous iron with the iron chelator resulted in reconstitution of cytokine responsiveness, thus demonstrating iron as the target for the chelator effect. Both tumor necrosis factor-alpha and interferon-gamma-induced interferon regulatory factor-1 gene transcription, as assessed by the measurement of unspliced, nascent, heterogeneous nuclear RNA, and treatment with iron chelators blocked tumor necrosis factor-alpha or interferon-gamma mediated interferon regulatory factor-1 gene transcription. Iron was not essential, however, for the association of interferon regulatory factor-1 mRNA with polyribosomes, suggesting iron was not essential for interferon regulatory factor-1 protein translation. Through such inhibitory regulation on pro-inflammatory transcription factors, iron chelators may serve as anti-inflammatory agents.