Dysregulation of upstream and downstream transforming growth factor-β transcripts in livers of children with biliary atresia and fibrogenic gene signatures

INTRODUCTION

Our previous work demonstrated that the transforming-growth factor (TGF) β pathway plays a central role in the liver fibrosis associated with experimental biliary atresia (BA). To confirm these findings in humans, we performed an in silico analysis of publicly available microarray data from liver specimens from children with BA, with the hypothesis that the TGF-β pathway would be dysregulated.

METHODS

We analyzed publicly available liver gene expression microarray data from 47 infants with BA. We re-analyzed the microarray image files and clinical data to compare gene expression differences between the fibrogenic and inflammatory cohorts identified in the initial study. Targets from the microarray analysis were confirmed using the animal model of BA.

RESULTS

Analysis of variance (ANOVA) detected 6903 transcripts (2822 distinct genes) differentially regulated between groups (p < 0.01; fold change >1.2). We used a targeted approach to identified a subgroup of 24 TGF-β-related transcripts. Expressions for procollagen transcripts were increased in the fibrogenic group (1.2-fold to 1.4-fold); expression of matrix metalloproteinase (MMP)-7 was similarly increased 2-fold, while MMP-9 and plasminogen activator inhibitor-1 were decreased 2-fold and 3-fold respectively. Integrins β5 (1.18-fold) and β8 (1.84-fold) also demonstrated increased expression in the fibrogenic group. Increased expression of β5 (3-fold) and β8 (5-fold) as well as Smad-3 (4-fold) and Smad interacting protein (SIP)-1 (3.5-fold) mRNA was confirmed in experimental BA. Phosphorylated Smad-3 protein in the experimental group was also nearly twice that of the control group, further implicating the TGF-β pathway.

CONCLUSION

Gene transcripts for known upstream and downstream TGF-β mediators are differentially expressed in liver specimens from children with BA and a fibrogenic gene signature. The same integrins that were dysregulated in the human specimens were also found to be up-regulated in our animal BA model, as were other intermediaries in the TGF-β pathway. Further investigation into whether these mediators may be attractive targets for future therapy in children with BA is warranted.

Inpatient weight loss as a precursor to bariatric surgery for adolescents with extreme obesity: optimizing bariatric surgery

BACKGROUND

As the obesity epidemic takes its toll on patients stricken with the disease and our health care system, debate continues regarding the use of weight loss surgery and its long-term consequences, especially for adolescents. One subset of patients regarding whom there is increased controversy is adolescents with extreme obesity (BMI > 60 kg/m(2)) because the risk of complications in this weight category is higher than for others undergoing bariatric surgery. Several strategies have been suggested for this patient group, including staged operations, combined operations, intragastric balloon use, and endoluminal sleeve placement. However, the device options are often not available to adolescents, and there are no data regarding staged or combined procedures in this age group.

METHODS

All adolescents with BMI >60 kg/m(2) referred to our program were evaluated for inpatient medical weight loss prior to laparoscopic sleeve gastrectomy. The program utilizes a multidisciplinary approach with a protein-sparing modified fast diet, exercise, and behavioral modification.

RESULTS

Three patients completed the program, and each achieved significant preoperative weight loss through the inpatient program and successfully underwent bariatric surgery.

CONCLUSIONS

Presurgical weight loss via an inpatient program for adolescents with a BMI >60 kg/m(2) results in total weight loss comparable to a primary surgical procedure alone, with the benefit of decreasing the perioperative risk.