Pediatr Res

Ultrastructural lesions in the small bowel of patients with cystic fibrosis.

Sbarbati A. Bertini M. Catassi C. Gagliardini R. Osculati F.
Institute of Normal Human Morphology, Ancona, Italy.
In the small bowel of patients with cystic fibrosis, primary defects involving both chloride transport and mucus secretion have been demonstrated, but there is no general consensus about the morphologic counterpart of functional and biochemical abnormalities. We have studied the intestinal mucosa in a group of patients with cystic fibrosis and gastrointestinal symptoms with the aim of evaluating whether the intestinal mucosa is normal as previously described. The results showed that the small bowel involvement is characterized by a typical pattern of lesions with preservation of the mucosal architecture and abundant mucus at the surface. In the villi, the absorbing cells were generally well preserved, but unusual features were found in the apical portion of the goblet cells, which formed sacks containing mucus droplets. Similar sacks were also found detached from the goblet cells. Aspects of degeneration were present in the upper portion of the crypts where elements with an extensive vacuolization of the cytoplasm and swelling were detectable. This study demonstrates that in patients with cystic fibrosis the ultrastructure of the small bowel mucosa is not normal as previously described, but that an ultrastructurally detectable enteropathy exists. This enteropathy seems to be localized mainly in sites where molecular biology studies described the highest expression of cystic fibrosis transmembrane conductance regulator.

A method for the quantitation of conjugated bile acids in dried blood spots using electrospray ionization-mass spectrometry.

Year 1998
Mills KA. Mushtaq I. Johnson AW. Whitfield PD. Clayton PT.
Biochemistry Unit, Institute of Child Health, London, United Kingdom.
Bile acid concentrations are elevated in the blood of neonates with cholestatic hepatobiliary disorders providing a possible means of screening for treatable conditions including biliary atresia. A method is described for the determination of concentrations of conjugated bile acids in dried blood spots using electrospray ionization mass spectrometry. Bile acids were eluted from the blood spots using methanol containing, as internal standards, the taurine and glycine conjugates of D4-chenodeoxycholic acid and D4-cholic acid. The samples were then reconstituted in acetonitrile/water and injected by autosampler into the electrospray source operating in negative ion mode. Optimal conditions were determined for both single quadrupole and tandem mass spectrometry analysis. Blood spot bile acid profiles were studied in two groups of infants (< 1 y), a cholestatic group (conjugated bilirubin > 25 mumol/L; n = 49), and a control group (n = 96). The best discrimination between the two groups was provided by measurements of taurodihydroxycholanoates (normal < 5 mumol/L; cholestatic group 18-94 mumol/L) and glycodihydroxycholanoates (normal < 5 mumol/L; cholestatic group 11-66 mumol/L). The method can also be adapted to detect unusual bile acids which are diagnostic of inborn errors of bile acid synthesis and peroxisomal disorders. The method is fast, reliable, reproducible, and relatively cheap; however, much more work is required to determine whether it can be used for mass screening for cholestasis. It will be necessary to show that measurement of bile acid concentrations in blood spots obtained at 7-10 d can be used to detect infants who currently present with jaundice, pale stools, and dark urine during the first 6 mo of life.

Epithelial tight junction structure in the jejunum of children with acute and treated celiac sprue.

Year 1998
Schulzke JD. Bentzel CJ. Schulzke I. Riecken EO. Fromm M.
Department of Gastroenterology, Universitatsklinikum Benjamin Franklin, Freie Universitat Berlin, Germany.
Tight junction morphology was analyzed in freeze fracture electron micrographs from biopsies at two locations along the surface-crypt axis in the jejunum of children with treated and untreated sprue and in control subjects. In control jejunum, strand number, meshwork depth, and total depth of the tight junction decreased from surface to crypt, consistent with the concept of the crypt being more permeable than the surface epithelium. In acute sprue, strand number was reduced in all regions along the surface-crypt axis, from 5.5+/-0.2 to 3.4+/-0.3 (surface) and from 4.7+/-0.2 to 3.6+/-0.1 (crypt). Meshwork depth was also reduced at all regions along the surface-crypt axis. Strand discontinuities were more frequent in acute sprue. Aberrant strands appeared below the main meshwork of crypt tight junctions in acute sprue. In asymptomatic children treated with the gluten-free diet, jejunal tight junctional structure only partially recovered. Strand number was restored to normal at the surface, but was still decreased in the crypts, from 4.7+/-0.2 to 3.9+/-0.3. We conclude that the epithelial barrier function of the small intestine is seriously disturbed by structural modifications of the tight junction in acute symptomatic celiac disease, thereby accounting for increased ionic permeability noted in a parallel study on identical specimens. This epithelial barrier defect may contribute to diarrhea in celiac disease by a "leak flux mechanism." In children with sprue treated with a gluten-free diet, barrier dysfunction was only partly recovered, suggesting a level of "minimal damage."

Growth, insulin-like growth factor I (IGF-I), and IGF-binding proteins 1 and 3 in children with severe liver disease before and after liver transplantation: a longitudinal and cross-sectional study.

Year 1998
Buzi F. Bontempelli AM. Alberti D. Jones J. Pilotta A. Lombardi A. Giustina A. Preece MA.
Clinica Pediatrica, Universita di Brescia, Italy.
We aimed to study the growth and growth factors of children with liver disease before and after liver transplantation (LT). Three observation intervals: 1) before LT (preLT), 2) after LT on daily prednisone treatment (dP), and 3) on alternate day prednisone (adP). A longitudinal study (LS) involved 17 infants (9 male) aged 0.73-2.38 y at LT; mean (+/- SD) height (Ht) SD score (SDS) at LT was -2.02 (+/- 1.25). In a cross-sectional study, there were 123 children (73 male) aged 0.16-14.88 y (mean 3.72 y). IGF-I and IGF binding proteins (BP) 1 and 3 were measured at the same intervals. The results were, for LS, preLT height velocity (HV) SDS (X +/- SD -0.8+/-1.4) lower (p < 0.01) than adP-HV SDS (3.1+/-1.8) but not different from dP-HV SDS (-1.0+/-1.9). For the cross-sectional study, dP-Ht SDS (X+/-SD -1.94+/-1.31) lower (p < 0.001) than preLT-Ht SDS (-1.03+/-1.06) and adP-Ht SDS (-0.98+/-1.20). Parental target SDS was not different from adP-Ht SDS. (Similar observations were made in the LS.) The dP- sitting height (SH) and subischial leg length (SLL) SDS were significantly lower than both preLT- and adP-SH SDS and SLL SDS (p = 0.02 and 0.002, respectively). There was a significant improvement of head circumference SDS and arm circumference SDS from preLT to adP. The dP and adP IGF-I and IGF-BP3 levels were greater than preLT levels (p < 0.001); no differences were found between preLT, dP, and adP IGF-BP1 levels. We conclude that growth in children with liver disease does not improve after LT on dP, but catch-up growth is shown on adP, appearing to depend mainly on the clinical course and corticosteroid regimen. IGF-I and IGF-BP3 increment on dP (and sustained on adP) is possibly due to liver regeneration, in contrast with inhibition of body growth on dP, possibly due to central and peripheral effects of corticosteroid.