Nanci Pittman

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.

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.

Distinct phenotype of early childhood inflammatory bowel disease

Goals Our goals were to answer 2 questions: (1) Is the presentation of early-onset inflammatory bowel disease (IBD) similar to typical adolescent-onset IBD? (2) Is there variability in familial aggregation in childhood IBD? Background The phenotype of IBD in children under 5 years of age (early-onset) is poorly defined. Clinical and genetic studies of IBD, however, generally assume the phenotype to be homogenous throughout childhood. Study We analyzed data from 413 consecutive pediatric IBD outpatients attending our center between 1995 and 2000. Disease type, anatomic distribution, and family history were compared between children presenting before (early-onset) and after the age of five (5 to 15 y). Results Disease presentation was predominantly colonic in early-onset IBD, most patients presenting with ulcerative colitis (UC). Isolated colonic disease was most frequent in early-onset Crohn disease (colonic 76.5%, ileocolic 24%) compared with ileocolic disease (ileocolic 45.5%, colonic 26%, ileal 19.4%, proximal 6.3%) in the older age group. First-degree family history was highest in early-onset UC 26% versus 11% in the older UC group. Conclusions We describe a distinct phenotype of early childhood onset IBD, with a strikingly high familial aggregation in UC and greater tendency to present with colonic disease. As more genetic heterogeneity is identified in IBD, careful definition of phenotype is required to identify further susceptibility genes. The early-onset form of UC presents an ideal group for further genetic analysis. These phenotype differences also suggest that treatment and outcome may vary in early-onset childhood IBD; prospective studies are required to confirm this.

Transcription of Cystic Fibrosis Transmembrane Conductance Regulator Requires a CCAAT-like Element for both Basal and cAMP-mediated Regulation

The cystic fibrosis transmembrane conductance regulator (CFTR) gene in man is controlled by a tightly regulated and weak promoter. The architecture of the CFTR promoter suggests regulatory characteristics that are consistent with the absence of a TATA-like sequence, including the ability to initiate RNA transcription at numerous positions. Detailed investigation of the most proximal region of the human CFTR gene promoter through deletion and mutational analysis reveals that expression is contingent on the conservation of the inverted CCAAT sequence. Basal expression of CFTR transcription and cAMP-mediated transcriptional regulation require the presence of an imperfect and inverted CCAAT element recognized as 5′-AATTGGAAGCAAAT-3′, located between 132 and 119 nucleotides upstream of the translational start site. RNA isolated from a transfected pancreatic cell line carrying integrated wild-type and mutant CFTR-directed transgenes was used to map the 5′ termini of the transgenic transcripts. Analysis of the transcript termini by ribonuclease protection analysis reflects the direct association of the conserved inverted CCAAT sequence in promoting transcript initiation. Because of the requirement for the inverted CCAAT sequence for promoting transcription of CFTR, the involvement of CCAAT-binding factors is suspected in the regulation of CFTR gene transcription. To test this, we used electrophoretic mobility shift assays to demonstrate that the majority of the binding to the inverted CCAAT element, between −135 and −116, was easily competed for by binding to cognate nucleotide sequences for CCAAT-enhancer binding protein (C/EBP). An antibody specific for the C/EBP-related protein, C/EBP, detected C/EBP as part of a nuclear protein complex bound to the inverted CCAAT sequence of the CFTR gene. Also, the detection of specific activating transcription factor/cyclic-AMP response element binding protein antigens by antibody supershift analysis of nuclear complexes suggest that species of this family of transcription factors could be involved in the formation of complexes with C/EBP within the CFTR gene inverted CCAAT-like element. These studies raise the possibility of interactions between individual members of the C/EBP and activating transcription factor/cyclic-AMP response element binding protein families potentially contribute to the tight transcriptional control rendered by the CFTR gene promoter.

Cognitive-behavioral Treatment of Persistent Functional Somatic Complaints and Pediatric Anxiety: An Initial Controlled Trial

Background: Children and adolescents who seek medical treatment for persistent physical distress often suffer from co‐occurring anxiety disorders. Treatment options for this impaired population are limited. This study tests the feasibility and potential efficacy of a cognitive‐behavioral intervention targeting pain and anxiety for youth with impairing functional physical symptoms and anxiety disorders presenting to pediatricians for medical care. Methods: Children and adolescents (aged 8–16) experiencing somatic complaints, without an explanatory medical disorder (i.e., functional), were recruited from primary care and specialty (gastroenterologists and cardiologists) pediatricians. Forty children, primarily with gastrointestinal symptoms, who met criteria for a co‐occurring anxiety disorder, were randomly assigned to a cognitive‐behavioral treatment addressing pain and anxiety, Treatment of Anxiety and Physical Symptoms (TAPS), or to a waiting list control. Results: TAPS was found to be an acceptable treatment for this population and was superior to the waiting list condition. Eighty percent of children in TAPS were rated as treatment responders by independent evaluators compared with none of the controls. Overall, self‐ and parent ratings indicated reductions in childrens somatic discomfort and anxiety following intervention. TAPS participants maintained clinical gains 3 months following treatment. Conclusions: The study supports the feasibility and preliminary efficacy of a cognitive‐behavioral intervention targeting co‐occurring physical distress and anxiety in youth presenting for medical treatment. Such an approach has the potential to exert broad impact on childrens dysfunction and to minimize exposure to invasive, ineffective, and costly medical procedures and treatments. Depression and Anxiety, 2011.

Percutaneous endoscopic gastrostomy tubes in pediatric bone marrow transplant patients

Background and Objectives: Nourishing a child undergoing bone marrow transplant (BMT) is essential, but the optimal method to achieve this is not established. The objectives of the study were to investigate the incidence and risk factors for complications of gastrostomy tubes in patients with BMT. Methods: A retrospective chart review was conducted of pediatric patients who received a percutaneous endoscopic gastrostomy (PEG) either for BMT or for other indications during a 3-year period. Occurrences of complications, absolute neutrophil count (ANC) at time of PEG placement, and ANC at time of complication were reviewed for both BMT and the comparison group. Results: Of the 11 subjects in the BMT group, 4 (36%) had a major complication of infection related to PEG and 3 of those required PEG removal. Two of the 4 subjects who developed a major complication were moderately neutropenic at the time of PEG placement and all subjects were neutropenic at the time of complication. Of the 30 subjects in the comparison group, only 1 (2.8%) had a major complication with cellulitis. There were no statistically significant differences between the 2 groups before PEG placement for age, weight, albumin, or white blood cell count. The incidence of complication in BMT compared with the comparison group was significant (P = 0.01). Conclusions: Our findings support that ANC should be considered before placement of PEG, significant neutropenia may be a contraindication for PEG placement in BMT patients, and other modalities for nutrition support might need to be considered.

Proactively Optimized Infliximab Monotherapy Is as Effective as Combination Therapy in IBD

Background Infliximab (IFX) discontinuation is not uncommon during the first year of treatment due to inadequate drug concentrations and anti-IFX antibodies (ATI). Both combination therapy and proactive therapeutic drug monitoring (pTDM) are used to decrease ATI and increase IFX durability. We proposed that monotherapy (Mono) is as effective as combination therapy (Combo) if the first maintenance infusion is dosed based on week 10 pTDM. Methods In a retrospective cohort of 83 patients with inflammatory bowel disease (IBD), we examined the frequency of IFX discontinuation, ATI, infusion reactions, and IFX concentrations during the first year of treatment in patients receiving week 10 pTDM-guided IFX monotherapy (Mono pTDM; n = 16) compared with patients on mono (n = 32) or combination therapy (n = 35) in whom TDM was introduced at or after week 14, per standard of care (SOC). Results The frequency of IFX discontinuation was lower with Mono pTDM compared with Mono SOC (P = 0.04) but did not differ with Combo SOC (P = 1). At first TDM, no patient in the pTDM strategy had ATI, vs 41% in Mono SOC (P = 0.002) and 6% in Combo SOC (P = 1). Of the 13 subjects with ATI in Mono SOC, 7 (47%) had ATI already at week 14. IFX trough concentrations with Mono pTDM were higher during maintenance compared with Mono SOC (9.5 vs 6.4 µg/mL, P = 0.04) but not Combo SOC. Conclusions Infliximab durability did not differ between patients on IFX monotherapy dosed based on p-TDM and patients receiving combination therapy. In the absence of concomitant immunosuppression, proactive TDM may improve IFX durability by maintaining higher IFX concentrations entering into maintenance. Further studies are needed to confirm our findings.

EBV Status and Thiopurine Use in Pediatric IBD.

Objectives: Epstein Barr virus (EBV) is a human herpes virus that infects 90% of the worlds population and has been linked to the development of lymphoproliferative disorders (LPDs) and immunosuppression. Primary EBV infection in patients with IBD on thiopurines is a risk factor for LPD, including lymphoma. We aimed to describe EBV status in a pediatric population with IBD with an emphasis on those initiating thiopurines. Methods: Electronic medical records and EBV serologies were reviewed and categorized into asymptomatic screening versus suspicion for acute infection. EBV status before therapy was described by sex, age, and therapeutic regimen. Descriptive statistics and univariate analysis were employed. Results: Only 150 (22%) of our 688 pediatric patients with IBD had documented EBV status regardless of age or treatment regimen. Only 17% were assessed for suspicion of acute infection and 83% for screening. Sixty-four (52%) screened patients were checked before starting any treatment and only 40% were immunoglobulin (Ig)G positive. There was no difference in mean age between the seronegative and seropositive group. The majority (63%) of thiopurine-treated patients were IgG negative before starting therapy. Eighty percent of primary EBV infections occurred on thiopurines at a mean (SD) of 2 ± 1.5 years after initiating therapy. Conclusions: The majority of our pediatric patients with IBD with documented EBV status were IgG negative at thiopurine initiation. Thiopurines were also associated with primary EBV infection. EBV status may be an important determinate of whether physicians prescribe thiopurines given the risk of primary EBV infections and lymphoproliferative diseases.