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Intestinal adaptation is enhanced by epidermal growth factor independent of increased ileal epidermal growth factor receptor expression.
J Pediatr Surg. 1998 Jul; 33(7):980-4; discussion 984-5.JP

Abstract

BACKGROUND/PURPOSE

Intestinal adaptation after massive small bowel resection (SBR) is augmented by epidermal growth factor (EGF) via an unknown mechanism. We recently have observed that EGF increases the expression of EGF receptor mRNA and protein content in the remnant ileum after SBR. The purpose of this study was to determine whether the magnitude of EGF-induced receptor expression correlates with intestinal adaptation.

METHODS

A 50% proximal SBR or sham operation (bowel transection with reanastomosis) was performed on male ICR mice. Animals from each group were then selected randomly to receive either human recombinant EGF (150 microg/kg/d) or saline by twice daily intraperitoneal injections. The remnant ileum was harvested at 1 week, and parameters of adaptation measured as changes in protein content. Ileal EGF receptor mRNA was quantitated using a ribonuclease protection assay. Changes in the expression ileal EGF receptor protein were determined by Western blot after immunoprecipitation. Comparisons of mean values between groups was performed using analysis of variance (ANOVA) and a P value of less than .05 was considered significant. Values are presented as mean +/- SEM.

RESULTS

EGF was mitogenic to the ileum after sham operation as monitored by increases in ileal protein content (2.21 +/- 0.002 mg/cm Sham v 2.97 +/- 0.25 mg/cm Sham +/- EGF; P < .05). After SBR, adaptation resulted in increased ileal protein content (4.45 +/- 0.27 mg/cm), which was substantially boosted by EGF (5.98 +/- 0.39 mg/cm; P < .05). No differences were detected in ileal EGF receptor mRNA or protein expression between Sham or SBR groups that did not receive EGF. However, EGF significantly enhanced the expression of ileal EGF receptor mRNA to an equal extent after both sham and SBR (approximately threefold). The magnitude of this increase in EGF receptor protein (four- to sixfold) was similar in both EGF groups as shown by Western blotting.

CONCLUSIONS

Changes in ileal EGF receptor expression are not mandatory for adaptation to occur. EGF upregulates the expression of mRNA and protein for its own intestinal receptor in vivo. Because EGF-induced receptor expression was comparable after both SBR and Sham operation, the beneficial effect of EGF during adaptation is likely caused by other factors in addition to increased receptor expression.

Authors+Show Affiliations

Children's Hospital Medical Center, Department of Surgery, University of Cincinnati College of Medicine, Ohio 45229-3039, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

9694081

Citation

Helmrath, M A., et al. "Intestinal Adaptation Is Enhanced By Epidermal Growth Factor Independent of Increased Ileal Epidermal Growth Factor Receptor Expression." Journal of Pediatric Surgery, vol. 33, no. 7, 1998, pp. 980-4; discussion 984-5.
Helmrath MA, Shin CE, Erwin CR, et al. Intestinal adaptation is enhanced by epidermal growth factor independent of increased ileal epidermal growth factor receptor expression. J Pediatr Surg. 1998;33(7):980-4; discussion 984-5.
Helmrath, M. A., Shin, C. E., Erwin, C. R., & Warner, B. W. (1998). Intestinal adaptation is enhanced by epidermal growth factor independent of increased ileal epidermal growth factor receptor expression. Journal of Pediatric Surgery, 33(7), 980-4; discussion 984-5.
Helmrath MA, et al. Intestinal Adaptation Is Enhanced By Epidermal Growth Factor Independent of Increased Ileal Epidermal Growth Factor Receptor Expression. J Pediatr Surg. 1998;33(7):980-4; discussion 984-5. PubMed PMID: 9694081.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Intestinal adaptation is enhanced by epidermal growth factor independent of increased ileal epidermal growth factor receptor expression. AU - Helmrath,M A, AU - Shin,C E, AU - Erwin,C R, AU - Warner,B W, PY - 1998/8/7/pubmed PY - 1998/8/7/medline PY - 1998/8/7/entrez SP - 980-4; discussion 984-5 JF - Journal of pediatric surgery JO - J Pediatr Surg VL - 33 IS - 7 N2 - BACKGROUND/PURPOSE: Intestinal adaptation after massive small bowel resection (SBR) is augmented by epidermal growth factor (EGF) via an unknown mechanism. We recently have observed that EGF increases the expression of EGF receptor mRNA and protein content in the remnant ileum after SBR. The purpose of this study was to determine whether the magnitude of EGF-induced receptor expression correlates with intestinal adaptation. METHODS: A 50% proximal SBR or sham operation (bowel transection with reanastomosis) was performed on male ICR mice. Animals from each group were then selected randomly to receive either human recombinant EGF (150 microg/kg/d) or saline by twice daily intraperitoneal injections. The remnant ileum was harvested at 1 week, and parameters of adaptation measured as changes in protein content. Ileal EGF receptor mRNA was quantitated using a ribonuclease protection assay. Changes in the expression ileal EGF receptor protein were determined by Western blot after immunoprecipitation. Comparisons of mean values between groups was performed using analysis of variance (ANOVA) and a P value of less than .05 was considered significant. Values are presented as mean +/- SEM. RESULTS: EGF was mitogenic to the ileum after sham operation as monitored by increases in ileal protein content (2.21 +/- 0.002 mg/cm Sham v 2.97 +/- 0.25 mg/cm Sham +/- EGF; P < .05). After SBR, adaptation resulted in increased ileal protein content (4.45 +/- 0.27 mg/cm), which was substantially boosted by EGF (5.98 +/- 0.39 mg/cm; P < .05). No differences were detected in ileal EGF receptor mRNA or protein expression between Sham or SBR groups that did not receive EGF. However, EGF significantly enhanced the expression of ileal EGF receptor mRNA to an equal extent after both sham and SBR (approximately threefold). The magnitude of this increase in EGF receptor protein (four- to sixfold) was similar in both EGF groups as shown by Western blotting. CONCLUSIONS: Changes in ileal EGF receptor expression are not mandatory for adaptation to occur. EGF upregulates the expression of mRNA and protein for its own intestinal receptor in vivo. Because EGF-induced receptor expression was comparable after both SBR and Sham operation, the beneficial effect of EGF during adaptation is likely caused by other factors in addition to increased receptor expression. SN - 0022-3468 UR - https://www.unboundmedicine.com/medline/citation/9694081/Intestinal_adaptation_is_enhanced_by_epidermal_growth_factor_independent_of_increased_ileal_epidermal_growth_factor_receptor_expression_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0022-3468(98)90518-8 DB - PRIME DP - Unbound Medicine ER -