title: Neuroimmune interaction and anorectal motility in children with food allergy-related chronic constipation.
abstract: OBJECTIVE
  Food allergy is thought to trigger functional constipation in children but the underlying mechanisms are still unknown. Mast cells (MCs) and their relationship with nerve fibers (NFs) in the rectal mucosa, as well as anorectal motility, were studied in children with refractory chronic constipation before and after an elimination diet for cow's milk, egg, and soy proteins.
  
  
  METHODS
  Thirty-three children (range: 1-10.8 years) underwent anorectal manometry and suction rectal biopsy before and after 8 weeks of oligoantigenic diet. MCs and NFs were identified immunohistochemically. Quantification of MCs (%MC/area) and MCs within 10 microm of NFs (%MC-NF/area) was performed by computer-assisted analysis.
  
  
  RESULTS
  Eighteen children responded to the diet (R-group) and fifteen did not (the NR-group). At baseline there was a significant difference in anal resting pressure (ARP; mm Hg), percentage of relaxation (%R), and residual pressure (RP; mm Hg) of anal canal during rectal distension between the R-group (66+/-4.1, 84.3+/-2.8, 10.4+/-2.3, respectively) and the NR-group (49+/-5, 92.2+/-1.7, 4.8+/-1.7, respectively; P<0.05). After the diet, significant changes in ARP, RP, and %R were observed only in the R-group (44+/-3.7, 93.7+/-1.5, 3.8+/-1.2, respectively; P<0.05). At baseline, the R-group showed an increase in %MC/area (8.3+/-0.7) and %MC-NF/area (5.2+/-2.6) with respect to the NR-group (5.1+/-0.5 and 2.3+/-0.4, respectively; P<0.05). After the diet, only the R-group showed a significant reduction of %MC/area and %MC-NF/area (4.4+/-0.5 and 2.2+/-0.4, respectively; P<0.001). Both ARP and RP significantly correlated with %MC/area and %MC-NF/area; %R showed a significant inverse correlation with both %MC/area and %MC-NF/area.
  
  
  CONCLUSIONS
  In children with food allergy-related chronic constipation, an increase in both rectal MC density and spatial interactions between MCs and NFs correlates with anal motor abnormalities. These variables are significantly affected by the diet.
authors.affiliation: Division of Pediatric Gastroenterology and Hepatology, Department of Pediatrics, University "La Sapienza," Rome, Italy.
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Borrelli
authors.forename: Giovanni
authors.initials: G
authors.lastname: Barbara
authors.forename: Giovanni
authors.initials: G
authors.lastname: Di Nardo
authors.forename: Cesare
authors.initials: C
authors.lastname: Cremon
authors.forename: Sandra
authors.initials: S
authors.lastname: Lucarelli
authors.forename: Tullio
authors.initials: T
authors.lastname: Frediani
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Paganelli
authors.forename: Roberto
authors.initials: R
authors.lastname: De Giorgio
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Stanghellini
authors.forename: Salvatore
authors.initials: S
authors.lastname: Cucchiara
mesh_terms: D001003:Anal Canal / Q000294:innervation / Q000473:pathology / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D003248:Constipation / Q000178:diet therapy / Q000209:etiology / Q000503:physiopathology*; D003672:Defecation / Q000502:physiology; D005260:Female; D005512:Food Hypersensitivity / Q000150:complications / Q000178:diet therapy / Q000503:physiopathology*; D006801:Humans; D007223:Infant; D008297:Male; D008365:Manometry; D008407:Mast Cells / Q000502:physiology; D009043:Motor Activity / Q000502:physiology*; D009412:Nerve Fibers / Q000502:physiology; D015213:Neuroimmunomodulation / Q000502:physiology*; D012007:Rectum / Q000294:innervation / Q000473:pathology / Q000503:physiopathology*