Transforming Growth Factor-Beta 3 Alters Intestinal Smooth Muscle Function: Implications for Gastroschisis-Related Intestinal Dysfunction

Background Gastroschisis (GS) is a congenital abdominal wall defect that results in the development of GS-related intestinal dysfunction (GRID). Transforming growth factor-beta, a pro-inflammatory cytokine, has been shown to cause organ dysfunction through alterations in vascular and airway smooth muscle. The purpose of this study was to evaluate the effects of TGF-beta 3 on intestinal smooth muscle function and contractile gene expression. Methods Archived human intestinal tissue was analyzed using immunohistochemistry and RT-PCR for TGF-beta isoforms and markers of smooth muscle gene and micro-RNA contractile phenotype. Intestinal motility was measured in neonatal rats +/- TGF-beta 3 (0.2 and 1 mg/kg). Human intestinal smooth muscle cells (hiSMCs) were incubated with fetal bovine serum +/- 100 ng/ml of TGF-beta 3 isoforms for 6, 24 and 72 h. The effects of TGF-beta 3 on motility, hiSMC contractility and hiSMC contractile phenotype gene and micro-RNA expression were measured using transit, collagen gel contraction assay and RT-PCR analysis. Data are expressed as mean +/- SEM, ANOVA (n = 6-7/group). Results GS infants had increased immunostaining of TGF-beta 3 and elevated levels of micro-RNA 143 & 145 in the intestinal smooth muscle. Rats had significantly decreased intestinal transit when exposed to TGF-beta 3 in a dose-dependent manner compared with Sham animals. TGF-beta 3 significantly increased hiSMC gel contraction and contractile protein gene and micro-RNA expression. Conclusion TGF-beta 3 contributed to intestinal dysfunction at the organ level, increased contraction at the cellular level and elevated contractile gene expression at the molecular level. A hyper-contractile response may play a role in the persistent intestinal dysfunction seen in GRID.