Domingo Balderramo

Donor mannose‐binding lectin gene polymorphisms influence the outcome of liver transplantation

Mannose‐binding lectin (MBL) is a C‐type lectin produced mainly by the liver that binds to a wide range of pathogens. Polymorphisms at the promoter and exon 1 of the MBL2 gene are responsible for low serum levels of MBL and have been associated with an increased risk of infections. We prospectively analyzed 95 liver transplant recipients. Well‐known functionally relevant polymorphisms of the MBL2 gene of the liver donor were examined by gene sequencing. Infectious events were collected prospectively. No differences in the incidence of infections were found according to the donor MBL2 genotypes. Survival was lower in patients receiving a liver graft from a donor with an exon 1 MBL2 variant genotype, and they had higher infection‐related mortality (50% versus 14%, P = 0.040). No differences were found according to other polymorphisms involving the promoter and 5′‐untranslated region. When we analyzed bacterial infection episodes, we found that patients receiving a liver from a donor with an exon 1 variant genotype had a higher incidence of septic shock (46% versus 11%, P = 0.004). Independent variables associated with graft or patient survival were as follows: receiving a graft from a donor with an exon 1 MBL2 variant genotype [adjusted hazard ratio (aHR), 9.64; 95% confidence interval (CI), 2.59‐36.0], the Model for End‐Stage Liver Disease score (aHR, 1.14; 95% CI, 1.05‐1.23), and bacterial infections (aHR, 11.1; 95% CI, 2.73‐44.9). Liver transplantation from a donor with a variant MBL2 exon 1 genotype was associated with a worse prognosis, mainly because of infections of higher severity. Liver Transpl 15:1217–1224, 2009.

Current management of biliary complications after liver transplantation: Emphasis on endoscopic therapy

Biliary complications occur in 5-25% of patients after liver transplantation and represent a major source of morbidity in this group of individuals. The major risk factor for most of these complications is ischemia of the bile tree usually due to obstruction or vascular insufficiency of the hepatic artery. The most common complications include biliary strictures (anastomostic and nonanastomotic), bile leaks, and biliary filling defects. The initial diagnostic approach starts with a high index of suspicion along with an abdominal ultrasound and Doppler exam. Magnetic resonance imaging is highly sensitive and is usually reserved for confirmation. The vast majority of these complications can be successfully treated with endoscopic retrograde cholangiography, however if this procedure cannot be performed a percutaneous approach or surgery is recommended. Nonanastomotic strictures and living donor recipients present a less favorable response to endoscopic management. This review focuses on the current diagnostic and therapeutic approaches for the management of biliary complications after liver transplantation.

Hepatic encephalopathy and post-transplant hyponatremia predict early calcineurin inhibitor-induced neurotoxicity after liver transplantation

Early calcineurin inhibitor‐induced neurotoxicity (ECIIN) is considered when neurological symptoms occur within 4 weeks after liver transplantation (LT). Risk factors and clinical outcome of ECIIN remain largely unknown. We sought to estimate the incidence, risk factors, and outcome of ECIIN after LT. We retrospectively evaluated 158 patients that underwent LT in a 2‐year period and received immunosuppression with calcineurin inhibitors (CNI) and prednisone. ECIIN was considered when moderate/severe neurological events (after excluding other etiologies) occurred within 4 weeks after LT and improved after modification of CNI. Demographic and clinical variables were analyzed as risk factors. Twenty‐eight (18%) patients developed ECIIN and the remaining 130 patients were analyzed as controls. History of pre‐LT hepatic encephalopathy (OR 3.16, 95% CI 1.29–7.75, P = 0.012), post‐LT hyponatremia (OR 3.34, 95% CI 1.38–9.85, P = 0.028), and surgical time >7 h (OR 2.62, 95% CI 1.07–6.41, P = 0.035) were independent factors for ECIIN. Acute graft rejection and infections were more frequent in the ECIIN group. In addition, length of stay was longer in ECIIN patients. In conclusion, pre‐LT hepatic encephalopathy, surgical time >7 h, and post‐LT hyponatremia are risk factors for ECIIN. Clinical complications and a longer hospital stay are associated with ECIIN development.

Complications after ERCP in liver transplant recipients

BACKGROUND Complications of the biliary tract after liver transplantation are successfully managed with ERCP; however, the incidence and risk factors for post-ERCP complications remain unknown. OBJECTIVE To examine the incidence, risk factors, and short-term outcome of post-ERCP complications in liver transplant (LT) recipients. DESIGN Retrospective evaluation of all ERCPs performed in LT recipients at our institution during a 7-year, 4-month period. SETTING Tertiary referral center. PATIENTS A total of 243 ERCPs performed in 121 LT recipients with duct-to-duct anastomosis. MAIN OUTCOME MEASUREMENTS Incidence of post-ERCP complications. Predictive factors were determined by univariate and multivariate analyses. RESULTS Overall complications occurred in 22 procedures (9%) (13 mild, 9 moderate): pancreatitis in 9 patients (3.7%), cholangitis in 8 patients (3.3%), postsphincterotomy bleeding in 4 patients (1.6%), and subcapsular hematoma in 1 patient (0.4%). The mean hospitalization for post-ERCP complications was 4.8 days (range 2-11 days). Logistic regression identified mammalian target of rapamycin inhibitors (odds ratio [OR], 4.65; 95% CI, 1.01-21.81; P = .049), serum creatinine level greater than 2 mg/dL (OR, 4.17; 95% CI, 1.07-16.26; P = .04), biliary sphincterotomy (OR, 3.03; 95% CI, 1.07-8.53; P = .037), and more than 2 pancreatic duct contrast injections (OR, 2.95; 95% CI, 1.10-7.91; P = .032) as independent risk factors for post-ERCP complications, whereas steroid therapy (OR, 0.23; 95% CI, 0.08-0.63; P = .004) was an independent protective factor. LIMITATIONS Single-center retrospective study. CONCLUSIONS The rate of complications after ERCP in LT recipients seems to be similar to that of non-LT recipients. Complications in this analysis were more common in LT recipients receiving mammalian target of rapamycin inhibitors and those with renal failure, biliary sphincterotomy, and more than 2 pancreatic duct injections, whereas they were less common in those patients on steroid therapy.

Changing etiologies and outcomes of acute liver failure: Perspectives from 6 transplant centers in Argentina

There is significant geographic variation in the etiologies and prognoses of acute liver failure (ALF). The aims of the present study were to determine the causes and short‐term outcomes of ALF in Argentina, to evaluate the performance of prognostic criteria, and to identify clinical prognostic factors of death. We performed a retrospective analysis of 154 adult patients with ALF who were admitted to 6 liver transplantation (LT) programs between June 2005 and December 2011. The most frequent causes of ALF were viral hepatitis B (46 patients or 30%), autoimmune hepatitis (AIH; 40 patients or 26%), and indeterminate causes (40 patients or 26%). No acetaminophen (ACM) overdose was reported. One hundred and twenty one patients (78%) were included on the waiting list, and LT was performed for 83 patients (54%). Overall survival rate is now corected to 73%. Multivariate logistic regression identified 2 independent variables associated with adverse outcomes on admission: a Model for End‐Stage Liver Disease (MELD) score ≥ 29 and an encephalopathy grade ≥ 3. In a direct comparison using a receiving operating characteristic curve analysis, the MELD score [C statistic = 0.830, 95% confidence interval (CI) = 0.73‐0.93] had better prognostic accuracy for predicting outcomes than the Clichy criteria (C statistic = 0.719, 95% CI = 0.58‐0.85) or the Kings College criteria (C statistic = 0.631, 95% CI = 0.49‐0.77). In conclusion, hepatitis B and AIH were the most frequent causes of fulminant hepatic failure in our series, and no cases of ACM overdosing were identified. A MELD score ≥ 29 and an encephalopathy grade ≥ 3 at admission were associated with death. The MELD score at admission showed the highest prognostic accuracy. Liver Transpl 20:483–489, 2014.

Influence of Mannose-Binding Lectin Gene Polymorphisms on The Invasiveness of Cytomegalovirus Disease After Solid Organ Transplantation

BACKGROUND Mannose-binding lectin (MBL) is a component of the innate immune system that binds the surface of pathogens, activating the complement pathway and acting as opsonin. Certain single-nucleotide polymorphisms of MBL2 are associated with a decrease in the circulating levels of MBL. Our aim was to evaluate the influence of MBL2 polymorphisms in the invasiveness of Cytomegalovirus (CMV) disease after solid organ transplantation. METHODS We include those solid organ transplant recipients who developed CMV disease posttransplant from 2000 to 2006. MBL2 genotyping was performed by sequencing of exon 1 (wild-type allele A and variants B, C, and D) and promoter regions (alleles H and L, X and Y, and P and Q). In the case of liver transplantation, donor MBL2 genotypes were analyzed. Associations were calculated by the chi-square test and binary logistic regression. RESULTS We included 45 transplant recipients with CMV disease (22 renal, 7 simultaneous kidney-pancreas, 11 liver, and 5 heart), of whom 10 (22%) had invasive CMV disease. No differences were found regarding HH (versus HL or LL), YY and YX (versus XX) and QQ (versus QP and PP) haplotypes with invasive CMV disease (P = 1.000 for all 3 comparisons). Patients with an exon 1 wild-type (AA) haplotype had 36% invasive CMV disease in comparison with 9% of patients with A/O or O/O haplotypes (P = .035). Binary logistic regression analysis showed that patients with exon 1 AA haplotype had an independent risk of developing invasive CMV disease (odds ratio, 6.0; 95% confidence interval, 1.1-32.5). CONCLUSIONS Our results suggest that exon 1 wild-type genotypes are associated with a higher risk of invasive CMV disease after solid organ transplantation.

Prospective Evaluation of Single-Operator Peroral Cholangioscopy in Liver Transplant Recipients Requiring an Evaluation of the Biliary Tract

In this descriptive study, we examined the role of single‐operator cholangioscopy (SOC) in the evaluation of biliary complications after liver transplantation (LT). We prospectively included adult recipients of deceased donor LT who were referred for endoscopic retrograde cholangiopancreatography between June 2009 and July 2011. All patients underwent SOC with biopsy of the biliary anastomosis. Sixteen patients were included: 12 with biliary anastomotic strictures (ASs), 2 with common bile duct stones, 1 with a bile leak, and 1 with sphincter of Oddi dysfunction. Patients with ASs displayed 1 of 2 patterns: (A) mild erythema (n = 9) or (B) edema, ulceration, and sloughing (n = 3). Those without ASs displayed a pale mucosa with mild edema at the anastomosis. Patients with ASs and pattern B required a longer period of stenting than patients with pattern A (457 versus 167 days, P = 0.01). In addition, patients with pattern A had a better response and better resolution of their strictures with endoscopic therapy than those with pattern B (88.9% versus 33.4%, P = 0.13). Histological examinations of ASs showed nonspecific intraepithelial inflammation in patients with patterns A and B. Biopsy samples from patients without ASs showed normal columnar epithelial bile duct cells. The total cholangioscopy time for all procedures was 26.8 ± 10.1 minutes. In conclusion, SOC in LT recipients is feasible and allows adequate visualization and tissue sampling of ASs and bile ducts. Two distinct visual patterns that are easily identified with SOC may help to predict the outcomes of endoscopic therapy in patients with biliary complications after LT. Liver Transpl 19:199‐206, 2013.

Risk factors and outcomes of failed endoscopic retrograde cholangiopancreatography in liver transplant recipients with anastomotic biliary strictures: A case‐control study

Anastomotic strictures (ASs) of the biliary duct after liver transplantation (LT) are primarily managed with endoscopic retrograde cholangiopancreatography (ERCP), but in some cases, this fails because of difficulties in passing the strictures. The aim of this case‐control study was to examine specific risk factors for initial ERCP failure and the outcomes of percutaneous transhepatic cholangiography (PTC) as a second‐line approach in LT recipients with ASs. Between January 2002 and December 2010, we identified LT recipients with ASs who experienced initial ERCP failure (which was defined as the inability to traverse the AS with guidewires in 2 or more consecutive procedures). A period‐matched control group (ratio = 1:2) with ASs and initial ERCP success was analyzed. Preoperative, intraoperative, postoperative, and endoscopic variables were evaluated as risk factors. The outcomes of PTC and the need for hepaticojejunostomy (HJ) or retransplantation were evaluated. Seventeen cases who experienced initial ERCP failure were compared with 34 controls. The median times from LT to ERCP were similar (8.7 months for cases and 8.6 months for controls, P = not significant). A multivariate analysis revealed that previous bile leaks [odds ratio (OR) = 6.07, 95% confidence interval (CI) = 1.0‐36.5] and more than 4 U of intraoperatively transfused red blood cells (OR = 11.51, 95% CI = 1.9‐71.2) were independent risk factors for failure. PTC was an effective second‐line treatment in only 3 of 12 cases (25%). The need for HJ was more frequent for the cases (13/17 or 76.5%) versus the controls (7/34 or 20.6%, P < 0.001). One patient in each group underwent retransplantation (P = not significant). In conclusion, previous bile leaks and high packed red blood cell transfusion requirements during surgery are risk factors for initial ERCP failure in LT recipients with ASs. A high proportion of these patients will need surgery as their final therapy. Liver Transpl 18:482–489, 2012.

Lack of TNFRI signaling enhances annexin A1 biological activity in intestinal inflammation.

We evaluated whether the lack of TNF-α signaling increases mucosal levels of annexin A1 (AnxA1); the hypothesis stems from previous findings showing that TNF-α neutralization in Crohns disease patients up-regulates systemic AnxA1 expression. Biopsies from healthy volunteers and patients under anti-TNF-α therapy with remittent ulcerative colitis (UC) showed higher AnxA1 expression than those with active disease. We also evaluated dextran sulfate sodium (DSS)-acute colitis in TNF-α receptor 1 KO (TNFR1-/-) strain with impaired TNF-α signaling and C57BL/6 (WT) mice. Although both strains developed colitis, TNFR1-/- mice showed early clinical recovery, lower myeloperoxidase (MPO) activity and milder histopathological alterations. Colonic epithelium from control and DSS-treated TNFR1-/- mice showed intense AnxA1 expression and AnxA1+ CD4+ and CD8+ T cells were more frequent in TNFR1-/- animals, suggesting an extra supply of AnxA1. The pan antagonist of AnxA1 receptors exacerbated the colitis outcome in TNFR1-/- mice, supporting the pivotal role of AnxA1 in the early recovery. Our findings demonstrate that the TNF-α signaling reduction favors the expression and biological activity of AnxA1 in inflamed intestinal mucosa.

Hepatocellular carcinoma in South America: Evaluation of risk factors, demographics and therapy

Hepatocellular carcinoma (HCC) is the second leading cause of cancer‐related death worldwide. Most studies addressing the epidemiology of HCC originate from developed countries. This study reports the preliminary findings of a multinational approach to characterize HCC in South America.