Distinct lung cell signatures define the temporal evolution of diffuse alveolar damage in fatal COVID-19

BACKGROUND

Lung damage in severe COVID-19 is highly heterogeneous however studies with dedicated spatial distinction of discrete temporal phases of diffuse alveolar damage (DAD) and alternate lung injury patterns are lacking. Existing studies have also not accounted for progressive airspace obliteration in cellularity estimates. We used an imaging mass cytometry (IMC) analysis with an airspace correction step to more accurately identify the cellular immune response that underpins the heterogeneity of severe COVID-19 lung disease.

METHODS

Lung tissue was obtained at post-mortem from severe COVID-19 deaths. Pathologist-selected regions of interest (ROIs) were chosen by light microscopy representing the patho-evolutionary spectrum of DAD and alternate disease phenotypes were selected for comparison. Architecturally normal SARS-CoV-2-positive lung tissue and tissue from SARS-CoV-2-negative donors served as controls. ROIs were stained for 40 cellular protein markers and ablated using IMC before segmented cells were classified. Cell populations corrected by ROI airspace and their spatial relationships were compared across lung injury patterns.

FINDINGS

Forty patients (32M:8F, age: 22-98), 345 ROIs and >900k single cells were analysed. DAD progression was marked by airspace obliteration and significant increases in mononuclear phagocytes (MnPs), T and B lymphocytes and significant decreases in alveolar epithelial and endothelial cells. Neutrophil populations proved stable overall although several interferon-responding subsets demonstrated expansion. Spatial analysis revealed immune cell interactions occur prior to microscopically appreciable tissue injury.

INTERPRETATION

The immunopathogenesis of severe DAD in COVID-19 lung disease is characterised by sustained increases in MnPs and lymphocytes with key interactions occurring even prior to lung injury is established.

FUNDING

UK Research and Innovation/Medical Research Council through the UK Coronavirus Immunology Consortium, Barbour Foundation, General Sir John Monash Foundation, Newcastle University, JGW Patterson Foundation, Wellcome Trust.

OPTIMAL: An OPTimized Imaging Mass cytometry AnaLysis framework for benchmarking segmentation and data exploration

Analysis of imaging mass cytometry (IMC) data and other low-resolution multiplexed tissue imaging technologies is often confounded by poor single-cell segmentation and suboptimal approaches for data visualization and exploration. This can lead to inaccurate identification of cell phenotypes, states, or spatial relationships compared to reference data from single-cell suspension technologies. To this end we have developed the "OPTimized Imaging Mass cytometry AnaLysis (OPTIMAL)" framework to benchmark any approaches for cell segmentation, parameter transformation, batch effect correction, data visualization/clustering, and spatial neighborhood analysis. Using a panel of 27 metal-tagged antibodies recognizing well-characterized phenotypic and functional markers to stain the same Formalin-Fixed Paraffin Embedded (FFPE) human tonsil sample tissue microarray over 12 temporally distinct batches we tested several cell segmentation models, a range of different arcsinh cofactor parameter transformation values, 5 different dimensionality reduction algorithms, and 2 clustering methods. Finally, we assessed the optimal approach for performing neighborhood analysis. We found that single-cell segmentation was improved by the use of an Ilastik-derived probability map but that issues with poor segmentation were only really evident after clustering and cell type/state identification and not always evident when using "classical" bivariate data display techniques. The optimal arcsinh cofactor for parameter transformation was 1 as it maximized the statistical separation between negative and positive signal distributions and a simple Z-score normalization step after arcsinh transformation eliminated batch effects. Of the five different dimensionality reduction approaches tested, PacMap gave the best data structure with FLOWSOM clustering out-performing phenograph in terms of cell type identification. We also found that neighborhood analysis was influenced by the method used for finding neighboring cells with a "disc" pixel expansion outperforming a "bounding box" approach combined with the need for filtering objects based on size and image-edge location. Importantly, OPTIMAL can be used to assess and integrate with any existing approach to IMC data analysis and, as it creates .FCS files from the segmentation output and allows for single-cell exploration to be conducted using a wide variety of accessible software and algorithms familiar to conventional flow cytometrists.

Identification of a protein expression signature distinguishing early from organising diffuse alveolar damage in COVID-19 patients

Diffuse alveolar damage (DAD) is the histological expression of acute respiratory distress syndrome and characterises lung pathology due to infection with SARS-CoV-2, and other respiratory pathogens of clinical significance. DAD reflects a time-dependent immunopathological process, progressing from an early/exudative stage through to an organising/fibrotic stage, yet within an individual these different stages of DAD may coexist. Understanding the progression of DAD is central to the development of new therapeutics to limit progressive lung damage. Here, we applied highly multiplexed spatial protein profiling to autopsy lung tissues derived from 27 patients who died from COVID-19 and identified a protein signature (ARG1, CD127, GZMB, IDO1, Ki67, phospho-PRAS40 (T246) and VISTA) that distinguishes early DAD from late DAD with good predictive accuracy. These proteins warrant further investigation as potential regulators of DAD progression.

GBMdeconvoluteR accurately infers proportions of neoplastic and immune cell populations from bulk glioblastoma transcriptomics data

BACKGROUND

Characterizing and quantifying cell types within glioblastoma (GBM) tumors at scale will facilitate a better understanding of the association between the cellular landscape and tumor phenotypes or clinical correlates. We aimed to develop a tool that deconvolutes immune and neoplastic cells within the GBM tumor microenvironment from bulk RNA sequencing data.

METHODS

We developed an IDH wild-type (IDHwt) GBM-specific single immune cell reference consisting of B cells, T-cells, NK-cells, microglia, tumor associated macrophages, monocytes, mast and DC cells. We used this alongside an existing neoplastic single cell-type reference for astrocyte-like, oligodendrocyte- and neuronal progenitor-like and mesenchymal GBM cancer cells to create both marker and gene signature matrix-based deconvolution tools. We applied single-cell resolution imaging mass cytometry (IMC) to ten IDHwt GBM samples, five paired primary and recurrent tumors, to determine which deconvolution approach performed best.

RESULTS

Marker-based deconvolution using GBM-tissue specific markers was most accurate for both immune cells and cancer cells, so we packaged this approach as GBMdeconvoluteR. We applied GBMdeconvoluteR to bulk GBM RNAseq data from The Cancer Genome Atlas and recapitulated recent findings from multi-omics single cell studies with regards associations between mesenchymal GBM cancer cells and both lymphoid and myeloid cells. Furthermore, we expanded upon this to show that these associations are stronger in patients with worse prognosis.

CONCLUSIONS

GBMdeconvoluteR accurately quantifies immune and neoplastic cell proportions in IDHwt GBM bulk RNA sequencing data and is accessible here: https://gbmdeconvoluter.leeds.ac.uk.

Down-regulation of MALAT1 is a hallmark of tissue and peripheral proliferative T cells in COVID-19

T cells play key protective but also pathogenic roles in COVID-19. We studied expression of long non-coding RNAs (lncRNAs) in COVID-19 T cell transcriptomes by integrating previously published single-cell RNA sequencing datasets. The long intergenic non-coding RNA MALAT1 was the most highly transcribed lncRNA in T cells, with Th1 cells demonstrating the lowest and CD8+ resident memory cells the highest MALAT1 expression, amongst CD4+ and CD8+ T cells populations, respectively. We then identified gene signatures that covaried with MALAT1 in single T cells. A significantly higher number of transcripts correlated negatively with MALAT1 than those that correlated. Enriched functional annotations of the MALAT1- anti-correlating gene signature included processes associated with T cell activation such as cell division, oxidative phosphorylation and response to cytokine. The MALAT1 anti-correlating gene signature shared by both CD4+ and CD8+ T cells marked dividing T cells in both lung and blood of COVID-19 patients. Focussing on the tissue, we used an independent patient cohort of post-mortem COVID-19 lung samples and demonstrated that MALAT1 suppression was indeed a marker of MKI67+ proliferating CD8+ T cells. Our results reveal MALAT1 suppression and its associated gene signature are a hallmark of human proliferating T cells.

The trajectory of COVID-19 cardiopulmonary disease: insights from an autopsy study of community-based, pre-hospital deaths

Background

Post mortem examination of lung and heart tissue has been vital to developing an understanding of COVID-19 pathophysiology; however studies to date have almost uniformly used tissue obtained from hospital-based deaths where individuals have been exposed to major medical and pharmacological interventions.

Methods

In this study we investigated patterns of lung and heart injury from 46 community-based, pre-hospital COVID-19-attributable deaths who underwent autopsy.

Results

The cohort comprised 22 females and 24 males, median age 64 years (range 19-91) at time of death with illness duration range 0-23 days. Comorbidities associated with poor outcomes in COVID-19 included obesity (body mass index >30 kg·m-2) in 19 out of 46 cases (41.3%). Diffuse alveolar damage in its early exudative phase was the most common pattern of lung injury; however significant heterogeneity was identified with bronchopneumonia, pulmonary oedema consistent with acute cardiac failure, pulmonary thromboembolism and microthrombosis also identified and often in overlapping patterns. Review of clinical records and next of kin accounts suggested a combination of unexpectedly low symptom burden, rapidly progressive disease and psychosocial factors may have contributed to a failure of hospital presentation prior to death.

Conclusions

Identifying such advanced acute lung injury in community-based deaths is extremely unusual and raises the question why some with severe COVID-19 pneumonitis were not hospitalised. Multiple factors including low symptom burden, rapidly progressive disease trajectories and psychosocial factors provide possible explanations.

Screening two biodegradable polymers in enhanced efficiency fertiliser formulations reveals the need to prioritise performance goals

Enhanced efficiency fertilisers (EEF) may reduce nitrogen (N) losses and improve uptake efficiency through synchronising N release with in-season plant requirements. We hypothesised that EEF formed via matrix encapsulation in biodegradable polymers will improve N use efficiency when compared to conventional urea fertiliser. This hypothesis was investigated for two biodegradable polymer matrices: polyhydroxyalkanoate (PHA), containing 11.6% urea (by mass), and polybutylene-adipate-co-terephthalate (PBAT), containing either 19.4 or 32.7% urea; and two contrasting soil types: sand and clay. Nitrogen availability and form was investigated under leaching conditions (water) with a growth accelerator pot experiment involving a horticultural crop and novel non-destructive three-dimensional scanning to measure in-season biomass development. The PBAT 32.7% formulation enabled greater above ground biomass production at both 50 and 100 kg N ha^-1 equivalent application rates compared to conventional urea. For the sandy soil, plant scanning indicated that improved uptake performance with PBAT 32.7% was probably the result of greater N availability after 25 days than for conventional urea. Two of the encapsulated formulations (PHA and PBAT 19.4%) tended to decrease nitrogen leaching losses relative to urea (P < 0.05 for the red clay soil). However, decreased N leaching loss was accompanied by poorer N uptake performance, indicative of N being less available in these biopolymer formulations. A snapshot of nitrous oxide emissions collected during peak nitrate concentration (prior to planting and leaching) suggested that the biopolymers promoted N loss via gaseous emission relative to urea in the sandy soil (P < 0.05), and carbon dioxide emissions data suggested that biopolymer-carbon increased microbial activity (P < 0.1). Controlled testing of N release in water was a poor predictor of biomass production and leaching losses. The diverse behaviours of the tested formulations present the potential to optimise biopolymers and their N loadings by taking into account soil and environmental factors that influence the efficient delivery of N to target crops. The greater N uptake efficiency demonstrated for the PBAT 32.7% formulation confirms our hypothesis that matrix encapsulation can enable better synchronisation of N release with crop requirements and decrease leaching losses.

Liver transplantation in children weighing less than 10 kg: Chilean experience

BACKGROUND

Orthotopic liver transplantation is the treatment of choice for most terminal liver diseases in children. In small children (≤ 10 kg), this procedure is challenging and has special considerations. The aim of this study is to describe the experience of a Chilean liver transplantation program in this subgroup of patients.

METHODS

The liver transplant database of Hospital Luis Calvo Mackenna and Clinica Las Condes was reviewed. All children less than 10 kg undergoing liver transplantation between January 1994 and July 2011 were included. Patient and graft outcomes and main complications were analyzed.

RESULTS

We have performed 230 pediatric liver transplantations, 49 of them in 41 patients weighing less than 10 kg. The first indication for transplantation was biliary atresia in 25 patients (61%). A living related donor was used in 23 cases (51%). Actuarial survival was 75.7% at 1 year and 67.1% at 5 years. The main cause of death was infection, and the leading cause of graft loss was vascular complication.

DISCUSSION

Our transplant program includes 2 centers that perform more than 90% of pediatric liver transplantations in Chile, including public health pediatric patients from all around the country. Patients weighing less than 10 kg represent the most challenging group in pediatric liver transplantation due to higher rates of vascular and biliary complications and postoperative infections.

Peripheral neuritis in psittacine birds with proventricular dilatation disease

Necropsies were performed on 14 psittacine birds of various species suspected to have proventricular dilatation disease (PDD). Eight of the birds exhibited neurological signs (seizures, ataxia, tremors and uncoordinated movements) and digestive tract signs (crop stasis, regurgitation, inappetance and presence of undigested food in the faeces). At necropsy, the birds had pectoral muscle atrophy, proventricular and ventricular distention, thinning of the gizzard wall, and duodenal dilation. In addition, five birds had a transparent fluid (0.2 to 1.0 ml) in the subarachnoidal space of the brain, and one bird had dilatation of the right ventricle of the heart. The histological lesions differed from earlier reports of PDD in that peripheral (sciatic, brachial and vagal) neuritis was seen in addition to myenteric ganglioneuritis, myocarditis, adrenalitis, myelitis and encephalitis.

Chilean experience in liver transplantation for acute liver failure in children

BACKGROUND

Acute liver failure (ALF) in children is a life-threatening condition, associated with high mortality, and in almost one third of the cases, with no other therapeutic option than orthotopic liver transplant (OLT). The aim of this study was to present our experience with OLT for ALF in pediatric patients in Chile. Patients fulfilling the criteria for ALF who were transplanted in our centers were prospectively included in an excel Microsoft database. We analyzed demographics, etiology, surgical techniques, complications, and long-term results.

PATIENTS AND METHODS

Between 1994 and 2009, we transplanted 52 pediatric patients with ALF. The most frequent known etiology was acute hepatitis A in 9 cases (18%), but in 26 cases (50%) it was impossible to determine the etiology. Thirty- one patients were males (63%). The overall mean age was 7.5 years and the mean weight, 28.1 kg. Thirty-five (67%) received a cadaveric graft. Among them in 18 cases (34%) the liver had to be reduced but 17 (33%) received whole livers. There were 17 (33%) recipients of living-related livers. Twenty-two patients needed reoperation, including 13 due to surgical complications (59%) and 9 (41%) as planned interventions. Ten patients were retransplanted.

RESULTS

Actuarial survival of patients at 1 year was 80% and at 5 and 10 years, 72%. Graft survival at 1 year was 79%, at 5 years 69%, and at 10 years 50%.

CONCLUSION

We have reported a series of pediatric liver transplant patients due to ALF whose results were comparable to other reported series. Living donor transplantation for ALF should be considered and offers a low morbidity rate without mortality.

Family interactions of liver transplanted children: are they normal?

Several psychosocial and behavioral problems have been reported in liver transplanted children. Most publications have focused on them, without considering their family environment. The aim of this study was to evaluate the interaction between liver transplanted children and their families, compared with a healthy control group. We selected liver transplanted children, between 8 and 12 years of age, with at least 6 months follow-up posttransplantation and in good clinical condition. Family structure also included 1 to 3 other children. Evaluable patients must have been living with their parents throughout the whole posttransplantation period. They were compared with a similar group of children without any chronic disease. A written informed consent was signed by both parents. All families were evaluated using a standard test consisting of different situations. The information was evaluated by 3 independent experts. Factors evaluated were limits (rules and limits of behavior), alliance-opposition (interaction between members to act), and hierarchy. Scoring was given to all observed acts. Statistical analysis was performed using chi-square tests with P < .05 considered significant. No statistical differences were found between groups in limits, alliance, and hierarchy. Our results showed that there were no differences in family structure and behavior between families of liver-transplanted and healthy children belonging to a similar socioeconomic level.

Pediatric Liver Retransplantation: Indications and Outcome

INTRODUCTION

Liver transplantation is the only treatment for end-stage liver disease. Not all patients have a favorable outcome. Graft failure secondary to primary nonfunction, vascular complications, or chronic rejection among other problems may lead to retransplantation. Retransplantation represents 8% to 29% of liver transplantations in the pediatric population. The aim of this study was to present our experience with retransplanted children by analyzing the indications and the results.

METHODS

All patients were prospectively included in our database, including 125 children. We included the indications for retransplantation, complications, and mortality. Kaplan-Meier curves were used for survival analysis.

RESULTS

Since 1994, 125 patients were transplanted and 25 were retransplanted (20%), including 5 who received a third graft. Primary nonfunction represented 30% of the indications for retransplantation and hepatic artery thrombosis, 20%. Six of 25 patients who received a first retransplantation and 2 of 5 who received a second retransplantation died. The most frequent cause of death was multiorgans failure. The survivals at 1 and 5 years were 82% and 76% for children receiving a first retransplantation, and 60% at 1 and 5 years for those who received a second retransplantation.

CONCLUSIONS

Organ failure after liver transplantation was a common event in pediatric transplantation. Survival was similar between patients transplanted once and those who received one retransplantation. Survival decreased among patients who received a third graft but was maintained at 60%, which is better than most published results for first retransplanted patients. Retransplantation is a valid option with good results for selected pediatric cases.

Hurler's syndrome: dental findings in a case treated with bone marrow transplantation in infancy

Hurler's syndrome, also known as mucopolysaccharidosis I (MPS I-H), is a rare condition inherited as an autosomal recessive trait. It is caused by a deficiency in alpha-L-iduronidase, an enzyme that participates in the degradation of the glycosaminoglycans (GAGs) heparin sulphate and dermatan sulphate. Children with Hurler's syndrome appear nearly normal at birth but, left untreated, show a progressive mental and physical deterioration caused by a build-up of GAGs in all organs of the body. Death is often caused by cardiac or respiratory failure and usually occurs before the second decade of life. In recent years, bone marrow transplantation (BMT) has been employed in the management of patients with Hurler's syndrome. However, the dental findings observed in these cases have not previously been reported in the dental literature. Here we report a patient aged 11 years and 6 months, presented to a Specialist Paediatric Dentistry Unit, who was successfully treated by BMT at 18 months of age.

Staple diet: a foreign body in a tooth

The chance discovery of a foreign object embedded in a tooth is uncommon, and requires radiographic examination to determine the composition and location of the object. The authors describe the case of an 11-year-old boy who presented with a staple lodged in the root canal of the maxillary left permanent central incisor. This staple was localized using parallax techniques and successfully removed from the canal. The radiographic techniques of localization and possible methods of removal of foreign bodies are discussed.

Living Related Liver Transplantation. Why This Option Has Been Discarded in a Pediatric Liver Transplant Program in Chile

Living related living transplantation (LRLT) has opened new possibilities for planning transplantation in better conditions for children with emergency situations and chronic liver diseases. Since we began the LRLT program in 1999, we have performed 57 pediatric liver transplants, 17 (29.8%) using living related donors (LRD). The aim of this study was to analyze the reasons why LRD were discarded as a therapeutic option. All pediatric patients were prospectively included in our Microsoft Excel database that was reviewed for obtaining information about causes why the LRLT could not be done. LRLT was proposed in 28 cases and performed in 17 (60.7%). The reasons for LRD rejection were: parent's fear of surgical complications in four cases; drug abuse in two; a mother without family support; medical reasons in two; and only one, due to anatomical reasons and in one case, cadaveric graft transplantation was performed while completing the father's evaluation. From these eleven cases, the indications for liver transplant were acute liver failure (ALF) in seven, biliary atresia in three, and Alagille syndrome in one. Nine were transplanted with cadaveric organs, but two patients with ALF died awaiting a liver. Efforts should be made to clarify the advantages and the disadvantages of LRD in each case, allowing parents to make a free, well-informed decision.

Pediatric Liver Transplantation: Ten Years of Experience in a Multicentric Program in Chile

Liver transplantation is the only treatment for patients with terminal acute and chronic diseases. Liver transplantation was started in Chile in 1985; our pediatric program began in 1993. The aim of this paper work was to present our experience from 1993 through 2004. One hundred and thirty two orthotopic liver transplants (OLT) were performed in children of mean age 5 years and median age 4 years (8 months to 15 years). The most frequent indications were biliary atresia, (43.1%) and acute liver failure (ALF; 20.4%), whose frequent cause was unknown but viral hepatitis A was the second one. A complete liver was transplanted in 59 patients, reduced in 39, split in one, and as an auxiliary liver in another one. Living related liver transplantation was performed in 32 cases (24.2%), of which thirty included segments II and III, and two, a right liver. A terminal arterial anastomosis was performed in 102 (77.2%) recipients and a graft interposition in 32 patients (24.2%). In 16 cases, biliary reconstruction was performed through an enterobiliary anastomosis. Immunosuppression included cyclosporine (Neoral), steroids, and azathioprine with conversion to tacrolimus (Prograf) as indicated. Rejection episodes, which were always biopsy-proven, were treated either with methylprednisolone or with antibodies. Biliary complications were the most frequent (21.4%) and the second cause was vascular complications (13%). Sixty-six patients suffered an acute rejection episode. Actuarial graft survival was 81.3% at 1 year and 72% at 5 years, while actuarial graft survival for ALF was 75.9% at 1 year and 67.8% at 5 years. Our results are comparable to those reported by most international groups.

ABO-incompatible liver transplantation: a new therapeutic option for patients with acute liver failure in Chile

Different ways have been suggested to expand donor numbers for liver transplantation. Transplantation using ABO-incompatible hepatic grafts has recently been a controversial issue due to the high risk of hyperacute rejection mediated by preformed anti-ABO antibodies. We report three patients with acute liver failure who were transplanted with ABO-incompatible livers: A to O in two patients and A to B in one case. We used pre- and posttransplant total plasma exchange, splenectomy, and triple immunosuppression. All three patients are alive; one graft was lost, probably secondary to thrombotic microangiopathy with low isohemagglutinin titers of 1:8. One patient developed acute cellular rejection that was reversed with a bolus of methylprednisolone. No antibody-mediated rejection occurred. Financial and infectious considerations have to be considered. In our series, the final liver transplantation cost was higher than average for acute liver failure. Plasmapheresis has the highest cost of all the additional procedures. ABO-incompatible liver transplantation, because of the splenectomy it requires, has been associated with more infections due to encapsulated organisms. However, with splenectomy in our three patients, none had infections due to these bacteria. In our country, we do not consider ABO-incompatible liver transplantation as a first-line option, except for highly selected patients.

The dental management of a patient with hyperimmunoglobulinemia E syndrome: a case report

Hyperimmunoglobulinemia E recurrent infection syndrome (also known as Job's syndrome) is a rare multi-system primary immunological disorder in which non-immunological abnormalities of the dentition, bones and connective tissue are also seen. A previous study has reported the occurrence of dental abnormalities in three-quarters of individuals diagnosed as suffering from this condition. The present authors report the case of a boy whose prolonged retention of the primary dentition was associated with delayed eruption of permanent teeth. They emphasize the need for early intervention in order to help minimize later orthodontic problems.

Special Care Dentistry: attitudes of Specialists in Paediatric Dentistry practising in the UK to the creation of a new specialty

OBJECTIVES

This study was designed to examine the attitudes of Specialists in Paediatric Dentistry (SPDs) practising in the UK towards the creation of a specialty of Special Care Dentistry (SCD).

DESIGN

Data were collected by postal questionnaire. Sample and methods. Two hundred and eleven dentists whose names were entered on the General Dental Council's Specialist List in Paediatric Dentistry, and who were resident and practising in the UK, were asked to complete a questionnaire consisting of both open and closed questions.

RESULTS

Questionnaires were returned by 167 (79.2%) of the eligible SPDs. One hundred and sixty respondents (95.8%) expressed an opinion in relation to the creation of a specialty of SCD. One hundred and forty-three respondents (85.6%) stated that they supported such a proposal. However, slightly fewer (n = 149) respondents were prepared to indicate what they considered to be the remit of the proposed specialty. Ninety-two respondents (55.1%) considered that it should be restricted to the provision of specialist care for adults with 'special needs'; the remaining 57 respondents felt that it should provide specialist care across the entire age spectrum.

CONCLUSIONS

Among SPDs, there is overwhelming support for the creation of a specialty of SCD, the majority view being that this should be dedicated to the provision of specialist care for adults with 'special needs'.

Epidemiology and results of liver transplantation for acute liver failure in Chile

Acute liver failure (ALF) is a severe, life-threatening condition associated with a high mortality rate. The objective of this study is to present the experience of a Chilean liver transplant program with orthotopic liver transplantation (OLT) for ALF. All patients with the diagnosis of ALF evaluated in our program between January 1995 and May 2003 were included in the analyses of etiology and outcomes. Candidates for OLT activated on a national waiting list were transplanted with cadaveric or living-related donor (LRD) organs. Twenty-seven patients age 1 to 19 years (median, 7.4 years) were transplanted at a median weight of 30.7 kg including 17 cadaveric and 10 with LRD livers. Most frequent etiologies were hepatitis A in 10 cases (37%) and unknown in 12 (48.1%). One donor experienced superficial phlebitis. Four patients were retransplanted (14.8%). Twenty patients are alive with 1- and 5-year survival rates of 74.1% At a median follow up of 34 months (range = 2 to 120). Seven patients died due to sepsis, multiorganic failure, graft primary nonfunction, intracranial hemorrhage, and intraoperative cardiac arrest. This experience revealed results comparable to international reports, allowing survival of patients destined to die.

Outcomes of orthotopic liver transplantation in Chile

Our liver transplant program was started in 1993 in a private clinic and a public hospital. Thereafter, a rapid increase in adults and pediatric candidates for this therapeutic option lead to this analysis of results in 165 orthotopic liver transplants (OLT) in 143 patients between November 1993 and December 2002. Seventy-four OLT were performed in 66 adult patients and 91 in the pediatric group. Liver grafts came from cadaveric donors in 145 cases (74 adults and 71 children). The technique of living-related donor was utilized in 20 pediatric cases. Main indications for OLT in the adult group were HCV cirrhosis, primary biliary cirrhosis; biliary atresia and acute liver failure were the indications in pediatric patients. Retransplantation was needed for 23 patients, including 9 adults and 14 children. The most frequent causes of death were sepsis, graft primary nonfunction, and vascular complications. Actuarial survivals at 1 and 5 years were 80.7% and 72.6% for the adult group and 82% and 74.8% for the pediatric group, respectively. Our results are comparable to those published by large, experienced, international centers, with much better financial support.