Neal S. Leleiko

Dysfunction of the intestinal microbiome in inflammatory bowel disease and treatment

BackgroundThe inflammatory bowel diseases (IBD) Crohns disease and ulcerative colitis result from alterations in intestinal microbes and the immune system. However, the precise dysfunctions of microbial metabolism in the gastrointestinal microbiome during IBD remain unclear. We analyzed the microbiota of intestinal biopsies and stool samples from 231 IBD and healthy subjects by 16S gene pyrosequencing and followed up a subset using shotgun metagenomics. Gene and pathway composition were assessed, based on 16S data from phylogenetically-related reference genomes, and associated using sparse multivariate linear modeling with medications, environmental factors, and IBD status.ResultsFirmicutes and Enterobacteriaceae abundances were associated with disease status as expected, but also with treatment and subject characteristics. Microbial function, though, was more consistently perturbed than composition, with 12% of analyzed pathways changed compared with 2% of genera. We identified major shifts in oxidative stress pathways, as well as decreased carbohydrate metabolism and amino acid biosynthesis in favor of nutrient transport and uptake. The microbiome of ileal Crohns disease was notable for increases in virulence and secretion pathways.ConclusionsThis inferred functional metagenomic information provides the first insights into community-wide microbial processes and pathways that underpin IBD pathogenesis.

Severe Pediatric Ulcerative Colitis: A Prospective Multicenter Study of Outcomes and Predictors of Response

BACKGROUND & AIMS In a prospective study of children with severe ulcerative colitis (UC), we aimed to assess outcomes and to identify predictors of nonresponse to intravenous corticosteroids. METHODS A total of 128 children (47% males; 12.9 +/- 3.9 y) hospitalized for severe UC were enrolled from 10 pediatric centers. Clinical and laboratory data and the Pediatric UC Activity Index (PUCAI) were recorded throughout the admission. Patients were followed up for 1 year postdischarge. RESULTS Thirty-seven (29%; 95% confidence interval [CI], 22%-37%) children failed intravenous corticosteroids and received, within 10.5 +/- 6.4 days, cyclosporine (n = 1; 3%), colectomy (n = 3; 8%), or infliximab (n = 33; 89%). Several predictors were associated with intravenous corticosteroids failure, but the best model included number of stools, amount of blood, age, and new-onset disease (odds ratio [OR], 1.9; 95% CI, 1.1-3.5; OR, 2.5; 95% CI, 1.3-4.6; OR, 1.2; 95% CI, 1.04-1.36; and OR, 0.27; 95% CI, 0.1-0.7, respectively). The PUCAI, followed closely by the Travis rule, strongly predicted response when compared with other measures (Seo and Lindgren indices, C-reactive protein level, and fecal calprotectin level) (P < .001). Aiming for sensitivity on day 3, a PUCAI greater than 45 screened for patients likely to fail intravenous corticosteroids (negative predictive value, 94%; positive predictive value, 43%; P < .001). Aiming for specificity on day 5, a PUCAI score greater than 70 optimally guided implementation of salvage therapy (positive predictive value, 100%; negative predictive value, 79%; P < .001). Twenty-five of 33 children treated with infliximab responded. The overall cumulative colectomy rate was 9% and 19% by discharge and 1-year, respectively. The day 3 PUCAI score predicted response up to 1 year postdischarge (P < .001; time to salvage therapy). CONCLUSIONS The PUCAI, calculated on days 3 and 5 of steroid therapy, can identify patients requiring salvage therapy. Infliximab is an effective therapy in steroid-refractory pediatric UC.

Alterations in the gut microbiome of children with severe ulcerative colitis.

Background: Although the role of microbes in disease pathogenesis is well established, data describing the variability of the vast microbiome in children diagnosed with ulcerative colitis (UC) are lacking. This study characterizes the gut microbiome in hospitalized children with severe UC and determines the relationship between microbiota and response to steroid therapy. Methods: Fecal samples were collected from 26 healthy controls and 27 children hospitalized with severe UC as part of a prospective multicenter study. DNA extraction, polymerase chain reaction (PCR) amplification of bacterial 16S rRNA, and microarray hybridization were performed. Results were analyzed in GeneSpring GX 11.0 comparing healthy controls with children with UC, and steroid responsive (n = 17) with nonresponsive patients (n = 10). Results: Bacterial signal strength and distribution showed differences between UC and healthy controls (adjusted P < 0.05) for Phylum, Class, Order, Family, Genus, and Phylospecies levels with reduction in Clostridia and an increase in Gamma‐proteobacteria. The number of microbial phylospecies was reduced in UC (266 ± 69) vs. controls (758 ± 3, P < 0.001), as was the Shannon Diversity Index (6.1 ± 0.23 vs. 6.49 ± 0.04, respectively; P < 0.0001). Steroid nonresponders harbored fewer phylospecies than responders (142 ± 49 vs. 338 ± 62, P = 0.013). Conclusions: Richness, evenness, and biodiversity of the gut microbiome were remarkably reduced in children with UC compared with healthy controls. Children who did not respond to steroids harbored a microbiome that was even less rich than steroid responders. This study is the first to characterize the gut microbiome in a large cohort of pediatric patients with severe UC and describes changes in the gut microbiome as a potential prognostic feature. (Inflamm Bowel Dis 2012)

Quantitative blood cultures in the evaluation of septicemia in children with Broviac catheters

We applied quantitative methods of analysis to all blood cultures drawn during the course of treatment in 28 children with Broviac catheters in a central vein. Thirty febrile episodes in 14 of these patients were evaluated. Samples of blood obtained from a peripheral vein and through the central catheter were cultured quantitatively on agar plates and nonquantitatively in standard broth media. Catheters were judged to be a source of septicemia nine times in seven children. In all nine positive catheter samples, the concentration of pathogens was 10 times as great as that observed in the peripheral venous sample. The blood drawn through the Broviac catheter contained greater than or equal to 2000 colony-forming units per milliliter in six cases. Quantitative cultures in two patients with septicemia not attributable to the catheter yielded low colony counts in the catheter sample. Cultures of blood samples drawn through the catheter when a child was well were not helpful in predicting subsequent septicemia. The technique of inoculating blood directly onto agar plates is easily performed and superior to standard broth cultures, because it detected pathogens within 16 hours and identified infections with multiple organisms.

Transcriptional repression of the cystic fibrosis transmembrane conductance regulator gene, mediated by CCAAT displacement protein/cut homolog, is associated with histone deacetylation.

Human cystic fibrosis transmembrane conductance regulator gene (CFTR) transcription is tightly regulated by nucleotide sequences upstream of the initiator sequences. Our studies of human CFTR transcription focus on identifying transcription factors bound to an inverted CCAAT consensus or “Y-box element.” The human homeodomain CCAAT displacement protein/cut homolog (CDP/cut) can bind to the Y-box element through a cut repeat and homeobox. Analysis of stably transfected cell lines with wild-type and mutant humanCFTR-directed reporter genes demonstrates that human histone acetyltransferase GCN5 and transcription factor ATF-1 can potentiate CFTR transcription through the Y-box element. We have found 1) that human CDP/cut acts as a repressor ofCFTR transcription through the Y-box element by competing for the sites of transactivators hGCN5 and ATF-1; 2) that the ability of CDP/cut to repress activities of hGCN5 and ATF-1 activity is contingent on the amount of CDP/cut expression; 3) that histone acetylation may have a role in the regulation of gene transcription by altering the accessibility of the CFTRY-box for sequence-specific transcription factors; 4) that trichostatin A, an inhibitor of histone deacetylase activity, activates transcription of CFTR through the Y-box element; 5) that the inhibition of histone deacetylase activity leads to an alteration of local chromatin structure requiring an intact Y-box sequence inCFTR; 6) that immunocomplexes of CDP/cutpossess an associated histone deacetylase activity; 7) that the carboxyl region of CDP/cut, responsible for the transcriptional repressor function, interacts with the histone deacetylase, HDAC1. We propose that CFTR transcription may be regulated through interactions with factors directing the modification of chromatin and requires the conservation of the inverted CCAAT (Y-box) element of the CFTR promoter.

Isolated intestinal transplantation: proof of clinical efficacy.

Background and Aims. Isolated intestinal transplantation has been limited by poor patient and graft survival. If high survival could be achieved and if parenteral nutrition-associated liver disease were reversible, this procedure could be more widely applied, with early liver dysfunction indicating the need for transplant evaluation. Methods. Twenty-six patients who had failed parenteral nutrition received 28 isolated intestinal transplants. We analyzed patient and graft survival, the effect of sirolimus on the severity and frequency of rejection, and the reversibility of liver dysfunction after transplant. Results. Three-year actuarial patient and primary graft survival were 88% and 71%, respectively. Two patients underwent successful retransplants. Twenty-two patients are alive at a mean of 21±15 (median 18; range 3–51) months. Actuarial survival with freedom from parenteral support is 81% at 3 years (21 of 26 patients). Actuarial freedom from parenteral support among survivors is 95.5% at 3 years (21 of 22 patients). Early rejection was less frequent with sirolimus (34% vs. 70% without sirolimus) (P =0.007). Moderate and severe rejection was less frequent with sirolimus (1/11 episodes vs. 9/17 episodes without sirolimus) (P =0.05). No grafts were lost after introduction of sirolimus. In all four patients with advanced liver dysfunction, fibrosis and cholestasis regressed within 1 year. Conclusions. High patient survival and parenteral nutrition-free survival can be achieved after isolated intestinal transplantation. Sirolimus treatment has eliminated graft loss. Parenteral nutrition-associated liver disease is reversible with intestinal transplantation. Refractory liver dysfunction in patients receiving parenteral nutrition should prompt consideration for isolated intestinal transplantation.

Intestinal transplantation before and after the introduction of sirolimus

Introduction. Small bowel transplantation has been limited by high rates of rejection and graft loss. In June 2000, we began using sirolimus, an immunosuppression agent with proven efficacy in kidney transplantation. We reviewed results among intestinal transplant recipients before and after the introduction of sirolimus. Methods. Thirty-one intestinal transplants were performed in 29 patients at our center between July 1998 and April 2001. All patients were followed for at least 30 days posttransplant. In the first 19 transplants (group 1), patients received tacrolimus, steroids, and antibody induction therapy (either daclizumab or OKT3). In the next 12 consecutive transplants (group 2), patients received tacrolimus, steroids, basiliximab, and sirolimus. Results. Eighteen children (7 males and 11 females, mean age 2.1±2.2 years) and 11 adults (9 males and 2 females, mean age 38.1±12.4 years) underwent transplantation. All patients survived transplantation. The overall reoperation rate was 1.7 procedures per patient in group 1 and 1.1 procedures per patient in group 2. The most common indications were abscess (n=7), planned second look (n=7), leaks/fistulas (n=6), dehiscence (n=6), obstruction (n=4), ischemic bowel (n=3), perforations (n=3), stomal complications (n=3), and graft removal (n=3). The incidence of biopsy-proven rejection in the first 30 days was 73.7% in group 1 and 16.7% in group 2 (P <0.002). Sirolimus was temporarily held or discontinued in 66.7% of patients. Actuarial 1-year graft survival was 91.7% with sirolimus and 57.9% without sirolimus (P <0.04). Actuarial 1-year patient survival was 91.7% with sirolimus and 79% without sirolimus (P =0.12). Conclusions. An immunosuppressive regimen that includes sirolimus has improved graft survival. Furthermore, this regimen has significantly decreased the incidence of early rejection and has eliminated early graft loss caused by fulminant rejection.

Faecal calprotectin, lactoferrin, M2-pyruvate kinase and S100A12 in severe ulcerative colitis: a prospective multicentre comparison of predicting outcomes and monitoring response

Objective To compare four faecal markers for their ability to predict steroid refractoriness in severe paediatric ulcerative colitis (UC). Construct validity and responsiveness to change were also assessed. Methods This was a prospective multicentre cohort study. Stool samples from 101 children (13.3±3.6 years; Pediatric UC Activity Index (PUCAI) at admission 72±12 points) were obtained at the third day of intravenous steroid therapy. Repeated samples at discharge were obtained from 24 children. Predictive validity was assessed using diagnostic utility statistics to predict steroid failure (ie, the need for salvage treatment). Concurrent validity was assessed using correlational analysis with the following constructs: PUCAI, Lindgren and Seo scores, physicians global assessment, albumin, erythrocyte sedimentation rate and C-reactive protein (CRP). Responsiveness was assessed using test utility and correlational strategies. Results Median values (IQR) were very high at baseline for all four markers (calprotectin 4215 μg/g (2297–8808); lactoferrin 212 μg/g (114–328); M2-pyruvate kinase (M2-PK) 363 U/g (119–3104); and S100A12 469 μg/g (193–1112)). M2-PK was numerically superior to the other three markers and CRP in predicting response to corticosteroid treatment (area under the receiver operating characteristic (ROC) curve 0.75 (95% CI 0.64 to 0.85; p<0.001) vs <0.65 for the others). However, it did not add to the predictive ability of the PUCAI (area under the ROC 0.81 (95% CI 0.73 to 0.89)). M2-PK also had the highest construct validity but with a modest mean correlation with all constructs (r=0.3; p<0.05). None of the markers was responsive to change (Spearmans rho correlation with change in the PUCAI <0.1; p>0.05, area under the ROC curve <0.65; p>0.05). Conclusions The four markers were greatly elevated in severe paediatric UC. Only M2-PK had good construct and predictive validity, and none was responsive to change. The PUCAI, a simple clinical index, performed better than the faecal markers in predicting outcome following a course of intravenous corticosteroids in severe UC.

Calicivirus Enteritis in an Intestinal Transplant Recipient

Protracted diarrhea of uncertain etiology is a significant problem following intestinal transplantation. We report an infant who developed severe secretory diarrhea 178 days after intestinal transplantation that persisted for more than 120 days. Repeated allograft biopsies demonstrated only nonspecific inflammation. Enzyme immunoassay (for rotavirus), culture, and reverse transcription polymerase chain reaction [calicivirus (Norwalk‐like virus)] were used to identify the allograft viral infection. A heavy density of calicivirus RNA nucleotide sequences (genogroup II, strain Miami Beach) was isolated from the jejunal and ileal allograft. Following a reduction in immunosuppressive therapy, diarrhea and enteritis remitted in association with the disappearance of all calicivirus RNA sequences. Calicivirus may cause severe allograft dysfunction in intestinal transplant recipients.

Recurrence of autoimmune hepatitis in children after liver transplantation

BACKGROUND Liver transplantation is recognized as the appropriate treatment for end-stage liver disease due to chronic active autoimmune hepatitis. While it was initially thought that the disease did not recur after transplant, it is now generally accepted that adult patients may develop recurrent disease, with studies reporting a recurrence rate of < or = 25%. We have noted a higher incidence of recurrent autoimmune hepatitis in our pediatric patients undergoing liver transplant, with a high incidence of associated morbidity. METHODS We reviewed the records of six children followed up for autoimmune hepatitis who underwent orthotopic liver transplant for complications of end-stage liver disease. RESULTS Of the six, five developed recurrent autoimmune hepatitis at a mean time of 11.4 months after transplant. The disease was aggressive, leading to cirrhosis and retransplant in three patients, within 1 year of recurrence. A second recurrence of disease occurred in all three retransplanted patients. One patient has received a third liver transplant, one has died, and one patient is asymptomatic on medical therapy. Autoimmune hepatitis recurred in all four patients receiving tacrolimus. CONCLUSION We conclude that liver transplant for autoimmune hepatitis is likely to be palliative for most pediatric patients. Potent immunosuppressives such as tacrolimus do not protect against the development of recurrent autoimmune hepatitis.