Anais Victor's research while affiliated with Paris Descartes, CPSC and other places

Background Intestinal atresia is a rare congenital disorder with an incidence of 3/10 000 birth. About one-third of patients have severe intestinal dysfunction after surgical repair. We examined whether prenatal gastrointestinal obstruction might effect on the myenteric plexus and account for subsequent functional disorders. Methodology/Principal Findings We studied a rat model of surgically induced antenatal atresia, comparing intestinal samples from both sides of the obstruction and with healthy rat pups controls. Whole-mount preparations of the myenteric plexus were stained for choline acetyltransferase (ChAT) and nitric oxide synthase (nNOS). Quantitative reverse transcription PCR was used to analyze mRNAs for inflammatory markers. Functional motility and permeability analyses were performed in vitro. Phenotypic studies were also performed in 8 newborns with intestinal atresia. In the experimental model, the proportion of nNOS-immunoreactive neurons was similar in proximal and distal segments (6.7±4.6% vs 5.6±4.2%, p = 0.25), but proximal segments contained a higher proportion of ChAT-immunoreactive neurons (13.2±6.2% vs 7.5±4.3%, p = 0.005). Phenotypic changes were associated with a 100-fold lower concentration-dependent contractile response to carbachol and a 1.6-fold higher EFS-induced contractile response in proximal compared to distal segments. Transcellular (p = 0.002) but not paracellular permeability was increased. Comparison with controls showed that modifications involved not only proximal but also distal segments. Phenotypic studies in human atresia confirmed the changes in ChAT expression. Conclusion Experimental atresia in fetal rat induces differential myenteric plexus phenotypical as well as functional changes (motility and permeability) between the two sides of the obstruction. Delineating these changes might help to identify markers predictive of motility dysfunction and to define guidelines for post-surgical care.

TaqMan oligonucleotide primers used for rat and human PCR analysis. (DOC)

Antibody references and concentrations for rat and human immunofluorescence analysis. (DOC)

Jejunoileal atresia represents about 40% of intestinal atresia. After surgical repair, intestinal motility disorders are burdened with the postoperative outcome, and the origin of these troubles remains unclear. To specify the physiopathologic feature of jejunoileal atresia, we developed an experimental surgical model in fetal rat. Time-dated pregnant rats were operated on at 18 days of gestational age. Hysterotomy was performed, followed by fetal wall incision. The exteriorization of the bowel loop was obtained by saline injection; the intestine was ligated and returned to the abdominal cavity before incisions were closed. Fetal intestine was excised at day 21, after cesarean delivery. Twenty-one pregnant rats underwent operation with 90% maternal survival rate. Among the 56 fetuses successfully operated on, 49 survived (87%). In fetuses with atresia, the mean birth weight (4.5 +/- 0.6 g) and the mean intestinal length (12.8 +/- 1.3 cm) were significantly lower compared to sham fetuses and controls. The rat model offers the advantage of a low-expense mammal model with a wide panel of probes and reagents available for the study of the gut. This model of jejunoileal atresia could be used to study the consequences of prenatal intestinal obstruction on fetal gut.