Independent modulation of enterocyte migration and proliferation by growth factors, matrix proteins, and pharmacologic agents in an in vitro model of mucosal healing.
BACKGROUND
Gastrointestinal mucosa heals by restitution and proliferation. These are difficult to distinguish in vivo.


METHODS
Human Caco-2 enterocytes were cultured on matrix proteins (collagen I, laminin, fibronectin) with growth factors (epidermal growth factor [EGF] and transforming growth factor-beta 1 [TGF-beta 1]) and the tyrosine kinase and prostaglandin inhibitors genistein and indomethacin. Healing was modeled by means of monolayer expansion, proliferation by means of 3H-thymidine uptake, and restitution by means of mitomycin-blocked migration.


RESULTS
Changing matrix composition failed to alter proliferation, but collagen I stimulated migration more than laminin or fibronectin (laminin/collagen, 68% +/- 2%; p less than 0.05). EGF (30 ng/ml) increased proliferation on both collagen (225% +/- 11% of basal) and laminin (206% +/- 26%) but increased migration only over laminin (210% +/- 17%) (all, p less than 0.05). TGF-beta 1 (200 pg/ml) stimulated migration over laminin (187% +/- 18%, p less than 0.005) but inhibited migration over collagen (89% +/- 3%, p less than 0.01) and did not affect 3H-thymidine uptake. When cultured on laminin, EGF but not TGF-beta 1 altered organization of the alpha 2 integrin subunit. Genistein (100 mumol/L) inhibited basal and EGF-stimulated 3H-thymidine uptake. In addition, it prevented EGF stimulation of replication-blocked migration (81% +/- 10% vs 190% +/- 20% of basal, p less than 0.0001) without altering basal replication-blocked migration. Indomethacin (10(-5) mol/L) did not alter migration but inhibited basal and EGF-stimulated proliferation by 7% +/- 1% (each, p less than 0.005).


CONCLUSIONS
Restitution and proliferation appear independently regulated by matrix and growth factors. It may be possible to individually target specific phases of mucosal healing by means of pharmacologic agents.
Basson
M D
MD
Department of Surgery, Yale University School of Medicine, New Haven, CT 06510.
Modlin
I M
IM
Flynn
S D
SD
Jena
B P
BP
Madri
J A
JA
D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000494:pharmacology; D016326:Extracellular Matrix Proteins / Q000494:pharmacology*; D019833:Genistein; D006133:Growth Substances / Q000494:pharmacology*; D006801:Humans; D007413:Intestinal Mucosa / Q000473:pathology / Q000503:physiopathology*; D007529:Isoflavones / Q000494:pharmacology; D007834:Lasers; D016685:Mitomycin / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D014446:Tyrosine 3-Monooxygenase / Q000037:antagonists & inhibitors; D014945:Wound Healing
D016326:Extracellular Matrix Proteins; D006133:Growth Substances; D007529:Isoflavones; D016212:Transforming Growth Factor beta; D016685:Mitomycin; D004815:Epidermal Growth Factor; D019833:Genistein; D014446:Tyrosine 3-Monooxygenase