Comparing the Performance of Multiple Small-Data Personalized Tacrolimus Dosing Models for Pediatric Liver Transplant: A Retrospective Study

Tacrolimus is a potent immunosuppressant used after pediatric liver transplant. However, tacrolimus's narrow therapeutic window, reliance on physicians' experience for the dose titration, and intra- and inter-patient variability result in liver transplant patients falling out of the target tacrolimus trough levels frequently. Existing personalized dosing models based on the area-under-the-concentration over time curves require a higher frequency of blood draws than the current standard of care and may not be practically feasible. We present a small-data artificial intelligence-derived platform, CURATE.AI, that uses data from individual patients obtained once daily to model the dose and response relationship and identify suitable doses dynamically. Retrospective optimization using 6 models of CURATE.AI and data from 16 patients demonstrated good predictive performance and identified a suitable model for further investigations.Clinical Relevance- This study established and compared the predictive performance of 6 personalized tacrolimus dosing models for pediatric liver transplant patients and identified a suitable model with consistently good predictive performance based on data from pediatric liver transplant patients.

Medical Management of Pediatric Inflammatory Bowel Disease (PIBD) in the Asia Pacific Region: A Position Paper by the Asian Pan-Pacific Society for Pediatric Gastroenterology, Hepatology, and Nutrition (APPSPGHAN) PIBD Working Group

Pediatric inflammatory bowel disease (PIBD) is rising rapidly in many industrialised and affluent areas in the Asia Pacific region. Current available guidelines, mainly from Europe and North America, may not be completely applicable to clinicians caring for children with PIBD in this region due to differences in disease characteristics and regional resources constraints. This position paper is an initiative from the Asian Pan-Pacific Society for Pediatric Gastroenterology, Hepatology and Nutrition (APPSPGHAN) with the aim of providing an up-to-date, evidence-based approach to PIBD in the Asia Pacific region, taking into consideration the unique disease characteristics and financial resources available in this region. A group of pediatric gastroenterologists with special interest in PIBD performed an extensive literature search covering epidemiology, disease characteristics and natural history, management and monitoring. Gastrointestinal infections, including tuberculosis, need to be excluded before diagnosing IBD. In some populations in Asia, the Nudix Hydrolase 15 (NUD15) gene is a better predictor of leukopenia induced by azathioprine than thiopurine-S-methyltransferase (TPMT). The main considerations in the use of biologics in the Asia Pacific region are high cost, ease of access, and potential infectious risk, especially tuberculosis. Conclusion: This position paper provides a useful guide to clinicians in the medical management of children with PIBD in the Asia Pacific region.

Management and monitoring of pediatric inflammatory bowel disease in the Asia-Pacific region: A position paper by the Asian Pan-Pacific Society for Pediatric Gastroenterology, Hepatology, and Nutrition (APPSPGHAN) PIBD Working Group: Surgical management, disease monitoring, and special considerations

Disease phenotype of pediatric inflammatory bowel disease (PIBD) in children from the Asia-Pacific region differs from that of children from the West. Many parts of Asia are endemic for tuberculosis, making diagnosis and management of pediatric Crohn's disease a challenge. Current available guidelines, mainly from Europe and North America, may not be completely applicable to clinicians caring for children with PIBD in Asia due to differences in disease characteristics and regional resource constraints. This position paper is an initiative from the Asian Pan-Pacific Society for Pediatric Gastroenterology, Hepatology and Nutrition (APPSPGHAN) that aims to provide an up-to-date, evidence-based approach to PIBD in the Asia-Pacific region. A group of pediatric gastroenterologists with a special interest in PIBD performed an extensive literature search covering epidemiology, disease characteristics and natural history, management, and monitoring. Attention was paid to publications from the region with special consideration to a resource-limited setting. This current position paper deals with surgical management, disease monitoring, immunization, bone health, and nutritional issues of PIBD in Asia. A special section on differentiating pediatric Crohn's disease from tuberculosis in children is included. This position paper provides a useful guide to clinicians in the surgical management, disease monitoring, and various health issues in children with IBD in Asia-Pacific region.

Prevalence, risk factors and parental perceptions of gastroesophageal reflux disease in Asian infants in Singapore

INTRODUCTION

Infant gastroesophageal reflux disease (GERD) is a significant cause of concern to parents. This study seeks to describe GERD prevalence in infants, evaluate possible risk factors and assess common beliefs influencing management of GERD among Asian parents.

METHODS

Mother-infant dyads in the Singapore PREconception Study of long-Term maternal and child Outcomes (S-PRESTO) cohort were prospectively followed from preconception to 12 months post-delivery. GERD diagnosis was ascertained through the revised Infant Gastroesophageal Reflux Questionnaire (I-GERQ-R) administered at 4 time points during infancy. Data on parental perceptions and lifestyle modifications were also collected.

RESULTS

The prevalence of infant GERD peaked at 26.5% at age 6 weeks, decreasing to 1.1% by 12 months. Infants exclusively breastfed at 3 weeks of life had reduced odds of GERD by 1 year (adjusted odds ratio 0.43, 95% confidence interval 0.19-0.97, P=0.04). Elimination of "cold or heaty food" and "gas producing" vegetables, massaging the infant's abdomen and application of medicated oil to the infant's abdomen were quoted as major lifestyle modifications in response to GERD symptoms.

CONCLUSION

Prevalence of GERD in infants is highest in the first 3 months of life, and the majority outgrow it by 1 year of age. Infants exclusively breastfed at 3 weeks had reduced odds of GERD. Cultural-based changes such as elimination of "heaty or cold" food influence parental perceptions in GERD, which are unique to the Asian population. Understanding the cultural basis for parental perceptions and health-seeking behaviours is crucial in tailoring patient education appropriately for optimal management of infant GERD.

The Associations Between Preoperative Anthropometry and Postoperative Outcomes in Infants Undergoing Congenital Heart Surgery

Aim:

We explored the association between preoperative anthropometry and biochemistry, and postoperative outcomes in infants with CHD after cardiac surgery, as infants with congenital heart disease (CHD) often have feeding difficulties and malnutrition.

Methodology

This was a retrospective review of infants (≤ 1-year-old) who underwent congenital heart surgery. Preoperative anthropometryin terms of preoperative weight-for-age z-score (WAZ), length-for-age z-score (LAZ), as well as preoperative serum albumin and hemoglobin concentrations, were evaluated against 6-month mortality, and morbidity outcomes including postoperative complications, vasoactive inotrope score, duration of mechanical ventilation, length of stay in the pediatric intensive care unit and in hospital, using the logistic regression or median regression models accounting for infant-level clustering.

Results

One hundred and ninety-nine operations were performed in 167 infants. Mean gestational age at birth was 38.0 (SD 2.2) weeks (range 26 to 41 weeks). Thirty (18.0%) infants were born preterm (<37 weeks). The commonest acyanotic and cyanotic lesions were ventricular septal defect (26.3%, 44/167), and tetralogy of Fallot (13.8%, 23/167), respectively. Mean age at cardiac surgery was 94 (SD 95) days. Feeding difficulties, including increased work of breathing during feeding, diaphoresis, choking or coughing during feeding, and inability to complete feeds, was present in 54.3% (108/199) of infants prior to surgery, of which 21.6% (43/199) required tube feeding. The mean preoperative WAZ was−1.31 (SD 1.79). Logistic regression models showed that low preoperative WAZ was associated with increased risk of postoperative complications (odds ratio 1.82; p = 0.02), and 6-month mortality (odds ratio 2.38; p = 0.008) following CHD surgery. There was no meaningful association between the other preoperative variables and other outcomes.

Conclusion

More than 50% of infants with CHD undergoing cardiac surgery within the first year of life have feeding difficulties, of which 22% require to be tube-fed. Low preoperative WAZ is associated with increased postoperative complications and 6-month mortality.

Feeding difficulties in Asian children with autism spectrum disorder

BACKGROUND

To characterize the nature and severity of feeding difficulties in Asian young children with Autism Spectrum Disorders (ASD) and identify potential predictors of poorer feeding outcomes.

METHODS

Cross sectional study of children aged 1-7 years with ASD. Parents completed the following: demographic information, brief autism mealtime behavior inventory, aberrant behavior checklist (ABC), behavioral pediatrics feeding assessment scale (BPFAS) and caregiver feeding style questionnaire. Additional information (medical data, cognitive and developmental assessment results, e.g., Autism Diagnostic Observation Schedule Second Edition, Autism Diagnostic Interview, Revised, Vineland Adaptive Behaviour Scales, etc.) were subsequently obtained from electronic medical records retrospectively by one of the study team members.

RESULTS

Of the 67 children, 28.4% had feeding difficulties (high BPFAS total frequency score). Caregiver feeding styles were authoritarian (34.8%) or indulgent (39.4%). Child characteristics did not significantly predict for the severity of feeding difficulties. Univariate analysis revealed that authoritarian feeding style (p = 0.001) and ABC hyperactivity score (p = 0.006) were significantly associated with BPFAS severity score. Multivariate analysis revealed that ABC hyperactivity score remained significantly associated with BPFAS severity score after controlling for all other ABC subscale scores. A final regression model including all child characteristics and ABC scores did not reveal any significant predictors of BPFAS total frequency score (R2 = 0.557).

CONCLUSION

Our findings suggest an association between hyperactivity, authoritarian feeding style and feeding difficulties. Children with ASD who have significant hyperactivity behaviors in the context of parents with an authoritarian feeding style should be actively screened for problematic feeding behaviors.

Effect of Oral Nutritional Supplementation on Growth in Children with Undernutrition: A Systematic Review and Meta-Analysis

Oral nutritional supplements (ONS) are used to promote catch-up growth in children with undernutrition. We conducted a systematic review and meta-analysis to summarize the evidence of ONS intervention effects on growth for 9-month- to 12-year-old children who were undernourished or at nutritional risk. Eleven randomized controlled trials met the inclusion criteria; trials compared changes in anthropometric measures in children using ONS or ONS + DC (dietary counselling) to measures for those following usual diet or placebo or DC alone. The RCTs included 2287 children without chronic diseases (mean age 5.87 years [SD, 1.35]; 56% boys). At follow-up time points up to 6 months, results showed that children in the ONS intervention group had greater gains in weight (0.423 kg, [95% confidence interval 0.234, 0.613], p < 0.001) and height (0.417 cm [0.059, 0.776], p = 0.022) versus control; greater gains in weight (0.089 kg [0.049, 0.130], p < 0.001) were evident as early as 7–10 days. Longitudinal analyses with repeated measures at 30, 60, and 90 days showed greater gains in weight parameters from 30 days onwards (p < 0.001), a trend towards greater height gains at 90 days (p = 0.056), and significantly greater gains in height-for-age percentiles and Z-scores at 30 and 90 days, respectively (p < 0.05). Similar results were found in subgroup analyses of studies comparing ONS + DC to DC alone. For children with undernutrition, particularly those who were mildly and moderately undernourished, usage of ONS in a nutritional intervention resulted in significantly better growth outcomes when compared to control treatments (usual diet, placebo or DC alone).

Clinical spectrum of paediatric liver diseases in Singapore

A wide spectrum of disorders can affect the liver. This spectrum of acute and chronic liver diseases in children differs among populations from various parts of the world because of inherent differences in genetic and environmental factors. This review article provides a concise overview of important paediatric liver disorders prevalent in Singapore and discusses the epidemiology and outcomes of these conditions specific to our local context.

Liver transplantation in children: the Singapore experience

Paediatric liver transplantation has come a long way since its acceptance as a treatment option for children with end-stage liver disease. From 1990 to 2020, a total of 434 liver transplants were performed in National University Hospital, Singapore, out of which 143 were performed in children. The majority of the liver grafts were from living donors, mainly the parents. Our long-term survival rates are comparable to those of major transplant centres worldwide. These patients usually have a productive and good quality of life.

Long-term outcome after liver transplantation in children with type 1 glycogen storage disease

Patients with GSD type 1 (von Gierke disease) are initially managed medically to maintain normoglycemia. However, if they do not achieve good metabolic control, LT is then considered. We describe the long-term outcome of 6 children with GSD type 1 who underwent LT. Retrospective chart review of the data of 6 children with GSD type 1 who underwent LT at National University Hospital, Singapore, from May 1998 to October 2018, was performed. The median (IQR) age at diagnosis of the GSD was 1 year (0.92-5.50) and at transplant was 13.88 years (11.46-16.38). All of the patients had elevated liver enzymes, hypercholesterolemia, hypertriglyceridemia, and hyperlactatemia prior to transplant. All of the patients are alive at the time of analysis and follow-up. None of them required a re-transplant. For the three patients who had hypoglycemia pretransplant, there was no recurrence post-transplant. All of the patients had normalization of liver enzymes by 1 year post-transplant. Long-term outcome of patients with GSD who underwent LT has been positive with improvement in metabolic control for most patients. We report the unusual finding of two siblings with persistent hyperuricemia post-transplant requiring allopurinol.

A Narrative Review on the Update in the Prevalence of Infantile Colic, Regurgitation, and Constipation in Young Children: Implications of the ROME IV Criteria

Regurgitation, colic, and constipation are frequently reported Functional Gastrointestinal Disorders (FGIDs) in the first few years of life. In 2016, the diagnostic criteria for FGIDs were changed from ROME III to ROME IV. This review assesses the prevalence of the most frequent FGIDs (colic, regurgitation and constipation) among children aged 0-5 years after the introduction of the later criteria. Articles published from January 1, 2016 to May 1, 2021 were retrieved from PubMed and Google Scholar using relevant keywords. A total of 12 articles were further analyzed based on the inclusion and exclusion criteria. This review consists of two studies (17%) from the Middle East, three (25%) from Asia, two (17%) from the USA, three (25%) from Europe, and one (8%) from Africa. Three studies (25%) were based on data obtained from healthcare professionals, while the rest were parent or caregiver reports. About half of the retrieved studies used the ROME IV criteria. Among infants aged 0-6 months, the reported prevalence of colic ranged between 10-15%, whilst that of regurgitation was 33.9%, and constipation was 1.5%. Among infants aged 0-12 months, the reported prevalence of regurgitation and constipation were 3.4-25.9% and 1.3-17.7%, respectively. The reported prevalence of constipation was 1.3-26% among children aged 13-48 months and 13% among children aged 4-18 years. Despite the large variations due to differences in diagnostic criteria, study respondents and age group, the prevalence of infantile colic was higher, while that for infantile regurgitation and constipation were similar using the ROME IV or III criteria.

Pediatric Inflammatory Bowel Disease in Asia: Epidemiology and natural history

Pediatric inflammatory bowel disease (PIBD) in Asia, once considered a rare entity, has seen a sharp increase in incidence over the preceding decade. However, there is a paucity of epidemiological data on PIBD in Asia, and the true disease burden is difficult to estimate due to the lack of national disease registries, prospective databases and the fact that much of existing published data are limited to single-center experiences. This sets the stage for examining recent published data on epidemiological trends and its natural history. Hence, we reviewed the relevant published literature on PIBD in order to summarize the epidemiological data in the Asian populations and compare it with the data available from the other population including Western population. Our review demonstrates that the rapid surge in PIBD incidence across Asian centers lies in contrast to the plateauing albeit high incidence rates in larger established Western cohorts. Important epidemiological trends observed across emerging Asian literature are the higher rates of perianal involvement at disease onset amongst pediatric Crohn's disease (CD) patients, a higher proportion of early-onset disease and the over-representation of the Indian ethnicity in multi-ethnic cohorts. A number of issues currently limit a robust comparison and hence the way forward would be to advocate the recognition of PIBD as an increasingly important public health problem with the need to establish robust disease registries.

Response and Lessons Learnt Managing the COVID-19 Crisis by School of Medicine, National University of Singapore

This article was migrated. The article was marked as recommended. Background: Healthcare professionals are playing an important role in the recent COVID-19 outbreak. It is crucial that the health systems maintain their ability to train students and residents during this time. However, there is a paucity of literature on the measures taken by higher education institutions to ensure academic continuity. The aim of this article is to share the systematic measures that were taken during the COVID-19 pandemic by Yong Loo Lin School of Medicine, National University of Singapore. Methods: We discussed our multi-faceted approach to protect students, staff and patients/ standardized patients during the COVID-19 outbreak that occurred during a pivotal time in the school's academic calendar. Results: Our approach to ensuring academic continuity and quality were based on best practices in the following areas: 1) A coordinated leadership and management process 2) Prioritising safety for all stakeholders 3) Dissemination of information amongst the stakeholders in a transparent and efficient way, and 4) Maintaining the rigour and quality of training. Conclusion: The initiatives were implemented as we leveraged on the available infrastructure and the collective team efforts of all involved. Further research will be done to evaluate the usefulness of these measures. We hope that this article would be a useful reference for other schools as they evaluate their pandemic preparedness in the event that the COVID-19 outbreak affects their country or similar crisis event in the future.

Cost-effectiveness analysis of antiviral treatment for pregnant women with high viral load to prevent hepatitis B virus vertical transmission

INTRODUCTION

Vertical transmission of the hepatitis B virus (HBV) is higher in infants born to pregnant women with a higher HBV DNA viral load even if the infants complete both active and passive vaccination. Although antiviral treatment is recommended for pregnant women during the antenatal period to reduce the rate of vertical transmission, most of them decline treatment.

METHODS

A decision tree was made to evaluate the costs and benefits involved when pregnant women either agreed or declined to take antiviral treatment during the antenatal period. The cost-effectiveness price was arrived at by multiplying the reduced vertical transmission rate with expenses of future medical care associated with vertical transmission.

RESULTS

From an individual mother's perspective, it was not cost-effective to receive antenatal antiviral treatment given the observed medication price and transmission rate in Singapore. However, the health system asserts that the current price of antiviral treatment is already far below the cost-effectiveness level, even without the Ministry of Health subsidies. Additionally, the awareness and perception of pregnant women also impacted treatment decisions.

CONCLUSION

By analysing the decision-making process, our result explained the current low uptake rates of antenatal antiviral treatment for HBV among pregnant women. We also concluded that from the health system's perspective, it was worth providing subsidies for perinatal antiviral treatment to prevent huge expenses generated in the future by chronic HBV complications.

Health-related quality of life, clinical outcomes, and subjective experiences of parent donors of pediatric liver transplant recipients

PURPOSE

The understanding of the HRQOL issues for parent donors of children who underwent LDLT is lacking. We evaluated the HRQOL of donor and non-donor parents, described their subjective experiences and identified factors associated with lower HRQOL post-donation.

METHODS

This is a cross-sectional study of parent donors whose children underwent LDLT, using SF-36v2 Health Survey to measure HRQOL, and a self-developed questionnaire to evaluate their subjective experiences.

RESULTS

Of 32 pairs of donor and non-donor parents, 27 donor and 19 non-donor parents responded. The data of respondents were analyzed. Both donor and non-donor parents' SF-36v2 norm-based scores were average or above average as compared to the Singapore population. Donors who made lifestyle changes post-donation (adopting a healthy balanced diet, regular physical activity, quitting smoking, and moderate alcohol intake) were associated with lower GH (P = 0.009) and PF (P = 0.002) scores. Donors who took more than 3 months for full recovery had lower RP (P = 0.022) and BP scores (P = 0.038). On multivariate analysis, recipient complication of Clavien grade 3 or 4 was associated with increased RP score by 8.71 points (95% CI: 1.74-15.68), after adjusting for time taken for full recovery. Majority (88.8%) had self-reported recovery time under 6 months and returned to work within 3 months (74.0%).

CONCLUSIONS

Donors with factors potentially associated with lower HRQOL may need more support to ensure better HRQOL outcomes post-donation.

Comparing monovalent and combination hepatitis B vaccine outcomes in children delivered by mothers with chronic hepatitis B

AIM

We compared the vaccine effectiveness of monovalent and combination hepatitis B vaccine regimens in infants born to chronic hepatitis B carrier mothers.

METHODS

An observational cohort of neonates was recruited over 78 months from two public hospital maternity units in Singapore. We enrolled term infants, born to chronic hepatitis B surface antigen-positive mothers regardless of their hepatitis Be antigen status, who completed the hepatitis B virus (HBV) vaccination programme in Singapore. Infants born to mothers on antiviral therapy, or with concurrent hepatitis C or human immunodeficiency virus infection were excluded. All infants received hepatitis B immunoglobulin at birth. One group received three doses of monovalent hepatitis B vaccine (0, 1, 6 months) (regimen A). The other group received two doses of monovalent vaccine, followed by one dose combination vaccine DTaP-IPV-Hib-HBV (0, 1, 6 months) (regimen B). Vaccine effectiveness was determined by immunoprophylaxis failure leading to HBV vertical transmission. Immunogenicity was assessed by hepatitis B surface antibody (anti-HBs) levels at 9 months of age.

RESULTS

Total of 177 term neonates received regimen A and 115 received regimen B. Immunoprophylaxis failure rate was low, 2.3 and 2.6% (P = 1.00) in regimen A and B, respectively. Mean anti-HBs titres were similar at 643 ± 374 and 561 ± 396 IU/L (P = 0.08) for regimen A and B, respectively.

CONCLUSION

Hepatitis B vaccine regimens using monovalent or combination vaccine for the third dose showed similarly high vaccine effectiveness and low immunoprophylaxis failure rate in term infants born to chronic hepatitis B carrier mothers.

Rapid rise in the incidence and clinical characteristics of pediatric inflammatory bowel disease in a South-East Asian cohort in Singapore, 1994-2015

OBJECTIVES

Epidemiological studies on pediatric-onset inflammatory bowel disease (PIBD) are scarce in South-East Asia (SEA). This study aimed to evaluate the incidence trend and clinical characteristics of PIBD in a SEA cohort in Singapore over 22 years (1994-2015).

METHODS

Case records of PIBD ≤18 years from the only two tertiary pediatric hospitals in Singapore were reviewed. The mean annual incidence (MAI) of PIBD was calculated based on Singapore's age-specific population data.

RESULTS

Overall MAI of PIBD was 1.26 per 100 000 (95% confidence interval [CI] 0.56-1.96). During the first decade (1994-2004) MAI was 0.23 per 100 000 (95% CI 0.08-0.39); this rose almost 10-fold to 2.28 per 100 000 (95% CI 1.15-3.41) during the second decade (2005-2015). Linear regression analysis showed significant increase in MAI over the 22-year period (r = 0.826, P < 0001). Of the 228 patients, 61.0% had Crohn's disease (CD), 30.3% ulcerative colitis and 8.7% IBD-unclassified, with a mdian age at diagnosis of 10.47 years and a male predominance (58.3%); 37.7% of them aged <10 years at diagnosis and 17.5% were very early-onset IBD. In CD, 27.3% had stricturing and/or penetrating disease and 21.6% were with perianal disease. Indians had a disproportionately high representation while positive family history was rare (1.3%).

CONCLUSIONS

Although PIBD is uncommon in Singapore, its incidence has risen dramatically over recent decades. A younger age of disease onset and higher proportions of perianal and stricturing/penetrating diseases suggest more aggressive disease than in Western data.

Sleep, activity and fatigue reported by Postgraduate Year 1 residents: a prospective cohort study comparing the effects of night float versus the traditional overnight on-call system

INTRODUCTION

As the traditional overnight call system was shown to contribute to fatigue, Singapore implemented a shift system in 2014. We aimed to compare activity levels, sleep (using a wrist actigraph), fatigue and professional quality of life between residents working on night float and those on overnight calls.

METHODS

All Postgraduate Year 1 (PGY1) residents at our institution were invited to participate. Participants were required to wear a wrist actigraph for four months and complete two validated surveys (Epworth Sleepiness Scale [ESS] and Professional Quality of Life [ProQOL] scale) once each at the start and end of the study.

RESULTS

49 residents were recruited. Night float and on-call residents showed a comparable median (range) number of steps (10,061 [1,195-15,923] vs. 10,649 [308-21,910]; p = 0.429), amount of sleep logged (361 [149-630] minutes vs. 380 [175-484] minutes; p = 0.369) and time taken to fall asleep (6 [0-14] minutes vs. 6 [range 0-45] minutes; p = 0.726), respectively. Night float residents had less efficient sleep, with 90.5% having sleep efficiency of over 85% compared to 100% of on-call residents (p = 0.127). More night float residents reported ESS scores > 10 (73.1% vs. 38.5%) and higher burnout scores on ProQOL scale (41.4% vs. 21.4%) at the start of the study. However, this was similar to the end of the study and not statistically significant.

CONCLUSION

Physical activity and amount of sleep were not significantly different between night float and on-call residents. Residents on night float reported comparatively more fatigue and burnout.

Predictors of Non-adherence to Immunosuppressive Therapy in Asian Liver Transplant Recipients

BACKGROUND

Adherence to immunosuppressive medications has been shown to affect post-transplant outcomes. We aimed to determine the level of adherence to immunosuppressive therapy in liver transplant (LT) recipients and to elucidate factors associated with it, as well as patient preferences on the dosing schedule.

METHODS

LT recipients were recruited during transplant clinic follow-up. A validated Morisky 8-item questionnaire was completed by patients to assess their adherence to immunosuppressive therapy. Adherence was determined by the sum of the responses to the questionnaire. Low, medium, and high adherence were defined by a Morisky score of >2, 1 to 2, and 0, respectively. Data on the patient's socio-economic and clinical background, dosing schedule of immunosuppressant medications, and patient preferences were included in the questionnaire.

RESULTS

A total of 107 LT recipients were approached and 75 completed the questionnaire. The majority of patients (48/74, 64.9%) preferred a once-daily medication regimen. The proportion of high adherence was 24/75 (32.0%), medium adherence was 51/75 (42.7%), and low adherence was 19/75 (25.3%). Multivariate analysis showed younger age and post-transplant duration >5 years as independent predictors for low adherence. Among low-adherence patients, 16/19 (84.2%) patients were on a twice-daily regimen, and, of these, 14/16 (87.5%) preferred their medications to be reduced to once daily.

CONCLUSIONS

A significant proportion (68%) of LT recipients had low to moderate adherence to medications, with younger age and longer post-transplant duration of >5 years as independent predictors. Early identification of at-risk patients is essential to allow implementation of measures to improve adherence. Simplifying medication regimens to once daily is a potential way to improve adherence.

Endoscopic retrograde cholangio-pancreatography in the management of biliary complications after paediatric liver transplantation - a retrospective study

The published paediatric experience with endoscopic retrograde cholangio-pancreatography (ERCP) in the diagnosis and management of biliary complications following liver transplantation (LT) is limited. We describe our experience with ERCP in the management of children following LT who presented with biliary complications, over a 20-year period (1995-2014). The retrospectively reviewed data are summarized descriptively. Of 94 children (47 boys) who received 102 liver transplants at our centre, seven children (five boys, two girls) underwent ERCP after liver transplantation. In total, 25 ERCP procedures were carried out in these patients. The median age at liver transplantation was 10.7 (3.9-16.2) years. The median interval between LT and the first ERCP was 28 days (12 days-6.8 years). All patients were on standard calcineurin-inhibitor-based immunosuppression regimens. Six of the seven patients underwent ERCP on more than one occasion [median number of ERCP sessions per patient- 4, (1-6)]. Seventeen procedures were carried out under conscious sedation, remaining eight under general anaesthesia. Sedation was achieved employing a standard regimen (Midazolam 5 mg with Pethidine 50 mg) and occasionally Fentanyl. ERCP is an effective and safe intervention from both diagnostic and therapeutic point of view, in the management of post-LT biliary complications in children.

Immune-modulatory genomic properties differentiate gut microbiota of infants with and without eczema

Gut microbiota play an important role in human immunological processes, potentially affecting allergic diseases such as eczema. The diversity and structure of gut microbiota in infants with eczema have been previously documented. This study aims to evaluate by comparative metagenomics differences in genetic content in gut microbiota of infants with eczema and their matched controls. Stools were collected at the age of one month old from twelve infants from an at risk birth cohort in a case control manner. Clinical follow up for atopic outcomes were carried out at the age of 12 and 24 months. Microbial genomic DNA were extracted from stool samples and used for shotgun sequencing. Comparative metagenomic analysis showed that immune-regulatory TCAAGCTTGA motifs were significantly enriched in the six healthy controls (C) communities compared to the six eczema subjects (E), with many encoded by Bifidobacterium (38% of the total motifs in the C communities). Draft genomes of five Bifidobacterium species populations (B. longum, B. bifidum, B. breve, B. dentium, and B. pseudocatenulatum) were recovered from metagenomic datasets. The B. longum BFN-121-2 genome encoded more TCAAGCTTGA motifs (4.2 copies per one million genome sequence) than other Bifidobacterium genomes. Additionally, the communities in the stool of controls (C) were also significantly enriched in functions associated with tetrapyrrole biosynthesis compared to those of eczema (E). Our results show distinct immune-modulatory genomic properties of gut microbiota in infants associated with eczema and provide new insights into potential role of gut microbiota in affecting human immune homeostasis.

Eosinophilic oesophagitis in children: an uncommon occurrence in a predominantly Chinese population in Singapore

INTRODUCTION

We aimed to determine the prevalence and clinical manifestations of eosinophilic oesophagitis (EoE) in children who presented to a tertiary care hospital in Singapore.

METHODS

We conducted a retrospective review of all oesophageal biopsies taken during oesophagogastroduodenoscopy (OGD) from March 2010 to December 2011. The patients' demographics and clinical characteristics were collected. Biopsies were reviewed by a single pathologist who was blinded to the original reports, using the current consensus criteria for the histological diagnosis of EoE.

RESULTS

Of the 88 children who had biopsies during OGD, 4 (4.5%) children (three boys, one girl; three Chinese, one Caucasian) were diagnosed with EoE. Their median age was 9.5 (range 4.0-12.0) years. The main clinical presentations were abdominal pain (in the three older children) and vomiting (in the youngest child). Three children had a history of atopy. Three children were diagnosed with EoE in the original histology reports, while one was diagnosed after the second review following histology demonstrating > 15 eosinophil granulocytes per high power field and microabscess formation. Endoscopy findings revealed oesophagitis in two children, one of whom was already on acid suppression therapy. Although three children were started on acid suppression therapy, they continued to be symptomatic. One child was also treated with swallowed fluticasone and two with food allergen avoidance, resulting in symptom improvement.

CONCLUSION

Although EoE is uncommon in Singapore, greater awareness is needed among family physicians and general paediatricians. Paediatric gastroenterologists should alert pathologists when sending biopsy specimens that are suspicious for EoE.

Limited benefit of hepatitis B immunoglobulin prophylaxis in children of hepatitis B e antigen-negative mothers

INTRODUCTION

In 2006, Singapore adopted the universal hepatitis B immunoglobulin (HBIg) policy. Since then, all infants of hepatitis B surface antigen (HBsAg)-positive mothers receive HBIg, irrespective of maternal hepatitis B e antigen (HBeAg) status. However, the benefits of HBIg for infants of HBeAg-negative mothers are unclear. We compared the vertical transmission rates among children of HBeAg-negative mothers who were given HBIg versus a retrospective cohort who were not given HBIg, to determine its protective effect.

METHODS

This observational study involved pregnant HBsAg-positive women seen at National University Hospital, Singapore, between June 2009 and December 2013. If the infants of these mothers completed the recommended vaccination schedule, they were recruited into the study, along with their older siblings. Serological testing for the children was performed three months after completion of the last dose of vaccine, and hepatitis B virus (HBV) surface gene sequencing was carried out if HBV DNA was detected.

RESULTS

A total of 111 infants and 47 siblings were recruited. 2 (1.5%) children were found to have vertical transmission despite receiving HBIg, while no incidences of vertical transmission were found among the historical controls who did not receive HBIg (p = 1.00).

CONCLUSION

The overall effectiveness of the hepatitis B vaccination programme for children of HBsAg-positive mothers was high, regardless of HBIg administration. The addition of HBIg did not appear to confer additional benefits, in terms of vertical transmission rate, among infants born to HBeAg-negative mothers.

Two consecutive partial liver transplants in a patient with Classic Maple Syrup Urine Disease

Maple syrup urine disease is caused by a deficiency in the branched chain ketoacid dehydrogenase (BCKAD) complex. This results in the accumulation of branched chain amino acids (BCAA) and branched chain ketoacids in the body. Even when aggressively treated with dietary restriction of BCAA, patients experience long term cognitive, neurological and psychosocial problems. Liver transplantation from deceased donors has been shown to be an effective modality in introducing adequate BCKAD activity, attaining a metabolic cure for patients. Here, we report the clinical course of the first known patient with classic MSUD who received two consecutive partial liver grafts from two different living non-carrier donors and his five year outcome posttransplant. We also show that despite the failure of the first liver graft, and initial acute cellular rejection of the second liver graft in our patient, his metabolic control remained good without metabolic decompensation.

Pulmonary Protothecosis in a Pediatric Liver Transplant Patient

Immunocompromised patients are susceptible to infections from common and unusual microorganisms. Protothecosis is seldom suspected on clinical grounds, yet it is readily diagnosed once detected in the laboratory. We report the first pediatric liver transplant recipient with pulmonary protothecosis, detected during an episode of Pneumocystis jirovecii pneumonia, and we conducted a review of the available literature.

When should we use partially hydrolysed formulae for frequent gastrointestinal symptoms and allergy prevention?

Experts reviewed the literature to determine whether partially whey hydrolysed formulas (HF) offer benefits in the dietary management of frequent gastrointestinal symptoms and allergy prevention. Compared with standard cow's milk-based formulas, partially whey HF confer a limited protective effect against allergic disease in high-risk infants, particularly atopic dermatitis, but not respiratory allergies. No randomised clinical trials have been published on partially whey HF in infants with colicky symptoms. The group did not find sufficient evidence to support the use of partially whey HF in regurgitation, although recent data suggest that a thickened partially whey HF may be more effective. Partially whey HF, fortified with prebiotics and/or probiotics, with high levels of sn-2 palmitate in the fat blend or without palm oil, provide some benefit in functional constipation.

CONCLUSION

Overall, partially whey HF may offer a useful alternative to intact protein in the dietary management of common functional gastrointestinal symptoms.

Supplementation with probiotics in the first 6 months of life did not protect against eczema and allergy in at-risk Asian infants: a 5-year follow-up

BACKGROUND

Healthy gut microflora is essential for oral tolerance and immunity. A promising approach to preventing allergic diseases in genetically at-risk infants is to introduce administration of probiotics early in life when their immune system is still relatively immature.

OBJECTIVE

In this follow-up study, we aim to determine if early-life supplementation with strains of probiotics has any long-term effect on allergic outcomes.

METHODS

We analyzed the charts and electronic databases of the PROMPT (Probiotics in Milk for the Prevention of Atopy Trial) study cohort. This cohort consisted of 253 infants at risk for allergy who were administered cow's milk supplemented with or without probiotics from the first day of life to the age of 6 months. The cohort was then followed up until the children were 5 years old and clinical outcomes were assessed.

RESULTS

Of the 253 children recruited into the study, 220 (87%) completed the follow-up. At the age of 5 years, there were no significant differences between the groups in the proportion of children who had developed any asthma, allergic rhinitis, eczema, food allergy and sensitization to inhalant allergens. Similar growth rates were observed in both groups.

CONCLUSIONS

The supplementation of probiotics in early childhood did not play a role in the prevention of allergic diseases. Clinical/Key Message: Early-life supplementation with probiotics did not change allergic outcomes at 5 years of age.

Academy of medicine, Singapore-Ministry of Health clinical practice guidelines: management of food allergy

The Academy of Medicine, Singapore (AMS) and the Ministry of Health (MOH) publish clinical practice guidelines to provide doctors and patients in Singapore with evidence-based guidance on managing important medical conditions. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the AMS-MOH clinical practice guidelines on the Management of Food Allergy, for the information of readers of the Singapore Medical Journal. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Academy of Medicine website: http://www.ams.edu.sg/guidelines.asp#foodallergy. The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

Effect of a milk formula containing probiotics on the fecal microbiota of asian infants at risk of atopic diseases

The fecal microbiota of 37 infants with (n = 20) or without (n = 17) probiotic administration was evaluated on D 3, and at 1, 3, and 12 mo by fluorescence in situ hybridization-flow cytometry (FISH-FC), PCR, and bacteriological culture methods. They represent consecutive subjects of an ongoing double-blind, placebo-controlled trial on a probiotic formula (LGG and Bifidobacterium longum) administered during the first 6 mo of life. Despite varying composition in each baby, there was a general bacterial colonization pattern in the first year. Bifidobacteria increased markedly (p = 0.0003) with a parallel decrease in Enterobacteriaceae (p < 0.001) and Bacteroides-Prevotella (p = 0.005) populations. Eubacterium rectale-Clostridium coccoides (p < 0.001) and Atopobium (p = 0.039) groups also gradually increased. This overall pattern was unaffected by probiotic administration (p > 0.05). B. longum (p = 0.005) and Lactobacillus rhamnosus (p < 0.001) were detected more frequently in probiotic group during supplementation, but no difference after supplementation had ceased (p > 0.05). Cultured lactic acid bacteria were also more numerous in the probiotic-administered babies during treatment period (log CFU/g 8.4 versus 7.4; p = 0.035). Our results indicate that supplemented strains could be detected but did not persist in the bowel once probiotic administration had ceased.

MARS: a futile tool in centres without active liver transplant support

BACKGROUND AND AIM

Studies on Molecular Adsorbent Recycling Systems (MARS) showed inconclusive survival benefits.

PATIENTS AND METHOD

We evaluated the efficacy of MARS for patients with either acute liver failure (ALF) or acute-on-chronic liver failure (AoCLF) at our centre, from February 2002 till April 2006 retrospectively.

RESULTS

Fifty ALF patients underwent median (range) three (1-10) sessions of MARS. Acute exacerbations of chronic hepatitis B (n=26) and drug-induced liver injury (n=12) were the commonest causes. Living donors were available in 6, 2 paediatric patients underwent left lobe and four adults underwent right lobe living donor liver transplant. Among the 44 ALF patients without a suitable living donor, one underwent deceased donor liver transplant and survived, another 19-year-old male with acute exacerbations of chronic hepatitis B recovered without transplant, and the rest died. Twenty-six had AoCLF and underwent four (1-10) MARS sessions. Sepsis (n=16) and upper gastrointestinal bleeding (n=4) were the commonest precipitating factors. None had a suitable living or deceased donor, suitable for transplantation during their hospitalization. Only one of 26 AoCLF patients survived the hospitalization, but the survivor died of sepsis 1 month later.

CONCLUSION

In this non-randomized study, survival after MARS was related to the availability of transplant, and in patients where living or deceased donor transplant was unavailable, MARS was of little benefit. Randomized-controlled trials on MARS((R)) are urgently needed to clarify its clinical utility.

Serum hepatocyte growth factor and vascular endothelial growth factor in children with acute liver failure

OBJECTIVES

Hepatocyte growth factor (HGF), a potent mitogen, and vascular endothelial growth factor (VEGF), a potent angiogenic factor, may play roles in hepatocyte regeneration in patients with acute liver failure (ALF). The aim of this study was to investigate serum levels of HGF and VEGF in children with ALF.

PATIENTS AND METHODS

Serum samples were collected on admission from 25 children with ALF (median age, 11.1 y; range, 1.3-17.1 y; 11 male, 14 female) and 12 normal children (9.1 y; range, 5.4-15.4 y; 6 male, 6 female). Aetiology of ALF was 13 non-A to E hepatitis, 3 viral, 3 toxic, and 6 other. HGF and VEGF in sera were assayed by enzyme-linked immunosorbent assay.

RESULTS

Median HGF levels in patients (10,157 pg/mL; range, 3412-73,420 pg/mL) were significantly higher than in controls (855 pg/mL, 510-1253 pg/mL; P < 0.001). Median VEGF levels in patients (164 pg/mL, 0-1588 pg/mL) were not significantly different from those in controls (214 pg/mL, 11-527 pg/mL). There was no relationship of HGF or VEGF levels to the aetiology of liver failure. There was a positive correlation between serum HGF and international normalized ratio (r = 0.73, P < 0.001), but not with levels of serum aspartate aminotransferase, bilirubin, or VEGF. There was no correlation between VEGF levels and international normalized ratio, aspartate aminotransferase or bilirubin.

CONCLUSIONS

Serum levels of HGF but not VEGF are increased in children with acute liver failure.

Referral patterns and waiting times for liver transplantation in Singapore

INTRODUCTION

Referral patterns, waiting times, waiting list, and mortality provide information on how effectively a transplant programme deals with referred patients. This paper aims to review these parameters in the Singapore National Liver Transplant Programme.

METHODS

Data of all patients referred to the Singapore National Liver Transplant Programme since its inception were captured and outcomes were retrieved and described.

RESULTS

562 patients were referred for liver transplant evaluation from 1990-2004, consisting of 457 adults and 105 children. The main indications for referral were hepatitis B liver disease and hepatocellular carcinoma in adults, and biliary atresia in children. Most patients were of United Network of Organ Sharing (UNOS) status 3 or 4 at the time of referral. 114 (20.28 percent) patients had transplants, consisting of 66 adults (14.44 percent) and 48 (45.71 percent) children. 138 adults and ten children were rejected for transplant, mainly for the reason of being "too early". The median waiting time for adults who had transplants was 3.3 months while adults still on the waiting list had been waiting for 16.2 months. The overall waiting list mortality was 44.3 percent, being 52.5 percent in adults and 23.2 percent in children.

CONCLUSION

The overall transplantation rate is low and the waiting list mortality is high as a result of low availability of organs, particularly in adults. Paediatric liver transplant appears to have been better at dealing with referred patients but this is probably due to availability of living-related liver transplant. Improvement in these may result from the Human Organ Transplant Act.

Liver transplantation in Singapore 1990-2004

INTRODUCTION

Liver transplantation is the accepted standard of care for patients with hepatocellular carcinoma, decompensated liver cirrhosis, and acute liver failure. Since the first liver transplant done in Singapore in 1990, results have been improving. We review the overall results of liver transplantation over the last 15 years.

METHODS

All transplant cases from 1990 to 2004 were reviewed retrospectively.

RESULTS

100 liver transplants were performed over the last 15 years; four in the first five years and 96 in the subsequent ten years. Overall one- and five-year survival rates were 80 percent and 78 percent, respectively. 44 were paediatric transplants, of which biliary atresia was the commonest indication for paediatric transplant. 56 were adult transplants of which hepatocellular carcinoma and decompensated hepatitis B cirrhosis were the commonest indications for adult transplant. Infection remained the commonest cause of mortality.

CONCLUSION

The number of transplants carried out per year was small due to the low cadaveric donation rate, but the survival of liver transplant patients was comparable to well-established liver transplant centres.

Outcome of liver transplantation for children with liver disease

INTRODUCTION

The advent of liver transplantation has revolutionised the outcome of children with both acute liver failure and chronic end-stage liver disease. The aim of this study was to review the outcome of all paediatric liver transplants performed since the National Liver Transplant Programme began in 1990.

METHODS

A retrospective review of all paediatric liver transplants from 1990 to December 2004 was performed.

RESULTS

46 liver transplants were performed in 43 children, of whom 23 (53.3 percent) were female. Median age at transplant was 21 months (range 11 months to 14 years). The most common indication for liver transplant was biliary atresia (71.7 percent). Living-related transplants accounted for 63 percent (29). Re-transplant rate was 6.5 percent with allograft loss as a result of hepatic artery thrombosis (two) and hepatic vein thrombosis (one). Tacrolimus was the primary immunosuppressive agent used in 89 percent of patients, with a 19.6 percent incidence of acute allograft rejection within the first six months. There were nine deaths. They were related to portal vein thrombosis (three), chronic rejection (one), sepsis (two), post-transplant lymphoproliferative disease (two) and primary graft non-function (one). Overall actuarial one- and five-year survival rate was 85.7 percent and 81.8 percent, respectively.

CONCLUSION

Liver transplantation is an established form of intervention for end-stage liver disease and a variety of liver-related metabolic disease. Our results are comparable to those of well-established liver transplant centres.

Comparison between effects of cyclosporine and tacrolimus on glomerular filtration rate in pediatric post-orthotopic liver transplant patients

Tacrolimus (FK506) and cyclosporine, synonymous with immunosuppressive therapy in organ transplantation, are not spared of potential adverse effects such as nephrotoxicity. We retrospectively compared their effects on cGFR in a post-OLT pediatric population. cGFRs of 32 patients from the LTUNUHS either on tacrolimus (group 1) or cyclosporine (group 2) from pretransplantation, transplantation and 3, 6, 9, 12, 18, 24, 30 and 36 months post-transplantation were compared. 95% CI and p-values were calculated for comparison with p < 0.05 considered significant. Longitudinal data analysis revealed no significant cGFR difference between groups 1 and 2 (p = 0.154). However, there was a significant difference in cGFR with time after transplantation (p < 0.0001). The mean difference score between both treatment groups was 277.92 (95% CI = 88.13-643.97). The survival rate post-OLT was 84.4%. In this retrospective sex-matched case controlled study of LTUNUHS patients, there was no difference between tacrolimus and cyclosporine on renal function. However, there was significant difference in cGFR with time post-OLT (p < 0.0001). The reason for this observation could be multifactorial.

Clinical and biochemical characterization of a patient with congenital disorder of glycosylation (CDG) IIx

We describe a case of congenital disorder of glycosylation with chronic diarrhea, progressive liver cirrhosis, and recurrent infections. Transferrin analysis showed only hyposialylation, but analysis of total serum N-glycans indicated loss of additional sugars, arguing that the latter generates a more informative picture to search for the primary defect.

Successful listing of patients for liver transplant was related to participation of referring doctor in the transplant program

INTRODUCTION

Experience with liver transplantation is limited in many parts of Asia. Therefore, patients from nontransplant centers may not be referred in a timely fashion for transplants. Our aim was to evaluate the pattern of referral for liver transplantation and their outcomes in Singapore.

METHODS

Consecutive patients referred from 1990 to 2001 were reviewed. Patients from any hospital in Singapore (or the region) could be referred to the program. They were discussed at the weekly meetings. Appropriate patients were placed on the waiting list. "Pending" indicated that the disease was early or there were unsettled medical or social issues. Unsuitable patients were "rejected" for transplant.

RESULTS

There were 385 patients referred over a 12-year period. Hepatitis B cirrhosis and hepatocellular carcinoma (HCC) were the most common indications among adults, whereas biliary atresia was the most common for children. Pediatric patients were more likely than adult patients to be listed for transplant (53/76 vs 106/309, P < .001). Patients referred by regular attendees of the program were more likely to be accepted than nonattendees (38% vs 25%, P = .04). "Disease too early", "advanced HCC", and "refusal by family members" were the most common reasons for rejection.

CONCLUSION

Members of the Liver Transplant Program were more likely to refer suitable patients for transplant at the appropriate time. Better interaction between gastroenterologists inside and outside the transplant program would help to improve the timing of referrals for liver transplantation, and hence, patient survival.

Human hepatocyte isolation and relationship of cell viability to early graft function

Hepatocyte transplantation is emerging as an additional modality of treatment for patients with acute liver failure or liver-based metabolic disorders. The procedure requires isolation of high-quality hepatocytes from unused donor livers. Hepatocytes were isolated from 20 donor livers (11 right lobes, 3 left lateral segments, 6 whole livers) using a collagenase perfusion technique. Cell viability (median 56%, range 13-95%) and yield (median 1.4 x 10(9) cells, range 2.0 x 10(6)-1.8 x 10(10) cells) varied according to the tissue available. Fatty livers rejected for transplantation gave lower cell viability (median 45%, range 25-59%). There was a significant correlation between age of donor (median 21 years, range 7-66 years) and viability of isolated hepatocytes in vitro (r = -0.683, p = 0.001). The 13 segments of livers were from reduced/split grafts used for clinical transplantation in 9 children and 4 adults. There was no significant correlation between in vitro cell viability and clinical parameters including intensive care stay, serum aspartate aminotransferase,and international normalized ratio (in the first 7 days), and allograft rejection or other early posttransplant complications, in patients transplanted with the corresponding tissue.

Transplant immunology

The immune response to an allogeneic transplanted organ is T-cell dependent. It is governed partially by the context in which the T-cell encounters the antigen and can range from apoptosis, anergy, and neglect to full activation. The current armamentarium of immunosuppressive agents acts to inhibit the various steps of this T-cell activation pathway; at the level of the T-cell receptor (monoclonal antibodies such as OKT3), intracellular signally (calcineurine-inhibitors), DNA synthesis (azathioprine), or to cause lymphocyte depletion (ATG, ALG). Most protocols use a combination of agents for induction and maintenance immunosuppression. Although successful in preventing and treating allograft rejection, they are not without side effects. With improved patient and graft survival rates, adverse events such as hypertension, nephrotoxicity, hyperglycaemia, and lymphoproliferative disease become increasingly important issues. Newer drugs (IL-2 receptor antagonists, mycophenolate mofetil, rapamycin) have been introduced in an attempt to spare or avoid these adverse effects. Inducing graft tolerance and long-term drug-free survival is the goal of transplant immunologists. Postulated mechanisms include clonal deletion, anergy, and immunoredirection. Although a number of methods have been tested experimentally, none has been proven to induce tolerance for routine clinical use. Immunosuppression remains the cornerstone of the success of organ transplantation. Until investigators are able to induce tolerance in their transplant recipients or develop a tolerance assay, they would need to continue to tailor their immunosuppressive therapy according to the risk profile of the individual recipient.

Mycophenolic acid pharmacokinetics in pediatric liver transplant recipients

The aim of this study is to study mycophenolic acid (MPA) pharmacokinetics in stable pediatric liver transplant recipients and determine which times best represent the area under the concentration versus time curve (AUC) of MPA plasma concentrations. MPA pharmacokinetic profiles were determined in 21 liver transplant recipients (age, 2 to 15 years; 12 boys) administered mycophenolate mofetil (MMF) for at least 6 months. Ten patients were coadministered cyclosporine A (CsA), and 11 patients were coadministered tacrolimus (Tac). Plasma MPA levels were analyzed by enzyme-multiplied immunoassay technique in blood samples at 0, 0.33, 0.67, 1.25, 2, 3.5, 5, and 7 hours after MMF administration. The AUC of plasma concentrations to 7 hours (AUC(0-7)) was calculated using the linear trapezoidal rule. MPA plasma trough concentration (C(0)), maximal concentration, and AUC(0-7) values ranged 9- to 14-fold at a median of 1.81 mg/L (range, 0.4 to 3.7 mg/L), 10.5 mg/L (range, 2.8 to 40.0 mg/L), and 30.2 mg/L.hr (range, 9.3 to 80.3 mg/L.hr), respectively. AUC(0-7) correlated significantly with MMF dose (r = 0.552; P =.010) and C(0) (r = 0.844; P <.001). Median AUC(0-7) (29.6 v 31.4 mg/L.hr; P =.918) was similar in children comedicated with CsA or Tac. Median MMF dose was greater in the CsA group (500 v 250 mg; P =.006). Consequently, median AUC(0-7) was significantly lower in the CsA group when equalized for dose and body weight (2.02 v 3.85 microg/L.hr per mg of MMF dose per kg of weight; P =.002). Variations of MPA pharmacokinetics in pediatric liver transplant recipients suggest that monitoring MPA plasma levels is required. C(0) correlates closely with AUC. Comedication with CsA increased MMF dosage requirements compared with children on Tac therapy.

Basiliximab (Simulect) for the treatment of steroid-resistant rejection in pediatric liver transpland recipients: a preliminary experience

BACKGROUND

The role of interleukin-2 receptor antibodies as rescue therapy in steroid-resistant rejection (SRR) has not been studied. We evaluated the safety and efficacy of an interleukin-2 receptor antibody, basiliximab (Simulect, Novartis, East Hanover, NJ), in treating SRR in pediatric liver transplant recipients.

METHODS

This was a prospective study of seven pediatric liver transplant recipients with biopsy-proven SRR who would have otherwise received OKT3 or antithymocyte globulin. The primary immunosuppression consisted of cyclosporine (Neoral, Novartis), azathioprine, and prednisolone in four patients and tacrolimus and prednisolone in three patients who had undergone retransplantation for chronic rejection (n=2) and hyperacute rejection (n=1). Four patients had received two cycles of high-dose steroids, and three patients had received a single cycle; all had been converted to tacrolimus, followed by the addition of mycophenolate mofetil.

RESULTS

The median time from transplant to SRR was 30 days (range, 8 days-23 months). Five children received two doses of basiliximab (10 mg, 3-7 days apart), and two children received a single dose. Aspartate aminotransferase levels normalized in three children 12, 21, and 30 days after basiliximab treatment. Aspartate aminotransferase levels decreased without normalizing in two children, but there was no further evidence of cellular rejection on repeat biopsies. All five children are rejection-free with a median follow-up of 22 months (range, 5-32 months). Biochemical abnormalities persisted in the remaining two children, and both developed chronic rejection. There were no immediate side effects associated with basiliximab. Two patients were treated empirically for possible cytomegalovirus infection 21 and 57 days after basiliximab treatment, with no evidence of cytomegalovirus disease.

CONCLUSION

Five of seven pediatric liver transplant recipients with SRR experienced successful outcomes with basiliximab treatment without major side effects, indicating that it is a safe alternative to OKT3 and other antilymphocyte antibodies.

Mycophenolic acid and mycophenolic acid glucuronide pharmacokinetics in pediatric liver transplant recipients: effect of cyclosporine and tacrolimus comedication

Determinants of the wide interindividual variability of the pharmacokinetics of mycophenolic acid (MPA) in 21 stable pediatric liver transplant recipients were investigated in relation to the kinetics of the drug's major phenolic glucuronide metabolite (MPAG), cyclosporin (CsA), or tacrolimus (Tac) co-medication and liver and renal function. Trough concentrations (C(0) ) most reliably predicted the area under the curve (AUC) of 0-7 hours MPA plasma concentrations (r (2) = 0.650). Co-medication with CsA demanded higher MPA mofetil (MMF) doses to achieve equivalent trough levels than Tac (362 vs. 178 mg per mg/L, P= 0.004). Median MPA C(0) (range) was significantly lower during CsA co-therapy when corrected for MMF dose (2.8 vs. 5.6 mg MPA/L for Tac, P= 0.006). The AUC of MPAG was correspondingly higher during CsA co-medication (229 vs. 94 mg/L/h for Tac, P = 0.012) with the MPA-to-MPAG ratio at C(0) correspondingly lower (0.10 vs. 0.14, respectively, P = 0.04). This suggested contrasting effects of CsA and Tac on MPA glucuronidation or its excretion and enterohepatic recirculation. MPAG AUC was correlated to body weight and creatinine clearance. Children with elevated aspartate transaminase (AST; but with no evidence of rejection on liver biopsy, n = 7) had significantly lower MPA trough levels compared with those in whom AST was normal (0. 77 vs. 1.76 mg/L, P = 0.05), but there was no difference in the MMF dose per body weight. Examination of the MPA profiles in these subjects showed significantly lower MPA concentrations from 120 minutes after dose until the end of the 7-hour profile and suggest an accelerated clearance or decreased enterohepatic recirculation.)

Acute liver failure

Acute liver failure (ALF) is a rare condition in the pediatric population. Patients who present with severe failure of liver synthetic function have a high mortality with medical therapy alone. The main causes of death are cerebral edema, hemorrhage, renal failure and sepsis. The etiology of ALF is age specific, with a significant number due to inborn errors of metabolism especially in neonates and infants. Treatment of children with ALF is supportive, aimed at preventing and managing associated complications until the native liver recovers or liver transplantation. Sedation should not be administered unless a decision for artificial ventilation has been made. As all children are potential transplant candidates, transfer to and management in a liver transplant centre is recommended. Prognostic criteria for mortality are less well defined compared to the adult population, although a significantly elevated INR > or = 4 carries a high chance of death, and liver transplantation should be considered at this stage. Auxiliary transplantation is an attractive option in selected individuals and provides the chance to stop immunosuppression should sufficient hepatic regeneration occur. The use of various liver assist devices and hepatocyte transplantation as a bridge to liver transplantation show promise, although when used in isolation, they do not have an impact on overall patient survival.