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©The Author(s) 2016.
World J Gastrointest Pathophysiol. Feb 15, 2016; 7(1): 38-47
Published online Feb 15, 2016. doi: 10.4291/wjgp.v7.i1.38
Published online Feb 15, 2016. doi: 10.4291/wjgp.v7.i1.38
Table 1 Phases of mammalian gastrointestinal development (adapted from reference 1)
Phase | Development |
Phase 1 | Embryonic phase of organogenesis |
Forms primitive GIT | |
Phase 2 | Entrance and exit sites of GIT form |
Formation of rudimentary primitive GIT | |
Formation of mouth and anus | |
Fetal swallowing of amniotic fluid begins | |
Phase 3 | Active differentiation |
Increase in cell number in crypts | |
Cells from crypts start migrating up to the villi | |
GIT growth is more rapid than the fetal body as a whole | |
Growth accompanied by selective apoptosis | |
Phase 4 | After birth, exposure to enteral nutrition |
Breast milk feeding – rapid mucosal differentiation and development | |
Infancy – mucosal growth continues with deepening crypts, increasing villi (increasing width and number) and appearance of sub-mucosal folds | |
Development of GIT mucosal immunity due to exposure to dietary antigens | |
Mucosal immune system can distinguish between foreign pathogens and safe nutrient proteins and commensal organisms | |
Phase 5 (Weaning) | Late infancy – early childhood. Transition from milk feeding to solid foods. This is second phase of mucosal immunity with epithelial hyperplasia with maturation of gut functions similar to older children. |
Table 2 Important nutritional components of amniotic fluid
Component | Most important examples |
Amino acids | Glutamine, arginine |
Proteins | Lactoferrin |
Minerals | Zinc, iron |
Hormones | Growth hormone, prolactin |
Growth factors | IGF-1, EGF |
Table 3 Amniotic fluid volume changes with increasing gestational age
Gestational Age | Volume of AF |
10 wk | 25 mL |
20 wk | 400 mL |
28 wk | 800 mL |
Term gestation | Plateau in volume of AF |
42 wk | 400 mL |
Table 4 Roles of various trophic factors found in amniotic fluid in intestinal development and the location of their receptors
Trophic factor | Location of receptors | Role in intestinal growth |
EGF | Basolateral intestinal membrane | Stimulates cell mitosis and differentiation |
Stimulates intestinal epithelial cell proliferation | ||
HGF | Intestinal crypt epithelial cells and in the muscle layers of the intestine | Intestinal cell proliferation in vitro and has been demonstrated to induce intestinal growth in rats |
TGF-α and TGF-β | Basolateral intestinal membrane | Primary role may be intestinal mucosal repair |
IGF-1 | Crypt cells, basolateral membrane and in the distal intestine | Primary mediator of both intrauterine and postnatal growth in mammals |
May be important for growth of muscle growth of distal small intestine | ||
EPO | Apical surface of intestinal epithelial cells | Increased villus height, villus area, crypt depth and crypt epithelia cell proliferation in rat pups. In vitro, recombinant EPO has been shown to protect cells against mucosal injury |
G-CSF | Apical regions of the intestine | Role in epithelial cell maintenance |
IL family | Intestinal epithelial cells | Enhances intestinal epithelial cell restitution. Enhances the integrity of the intestinal epithelial cell junctions. Intestinal epithelial cell proliferation and increased nutrient uptake |
Table 5 Effects of epidermal growth factor on the gastrointestinal tract
Increased effect on | Possible secondary message |
Proliferation | - |
Bicarbonate secretion | Prostaglandins |
NaCl and glucose uptake | Na+- glucose cotransporter, lipids |
Mucus secretion | Prostaglandins |
GI blood flow | Beta-adrenergic NO prostaglandins |
Longitudinal smooth muscle contraction | Prostaglandins |
Circular smooth muscle contraction | Desensitizes (not prostaglandins) |
Restitution | Cell-migration prostaglandins |
Permeability | - |
Mucosal protection | Proliferation, polyamines, mucus, trefoil peptides |
Decreased effect on | Possible secondary message |
Gastric acid secretion | Protein kinase C, cAMP |
Gastric emptying | - |
Increased and decreased effect on | Possible secondary message |
Chloride secretion | Phosphatidylinositol 3-kinase |
Pancreatic amylase (3.2.1.1) secretion | cAMP phospholipase C |
Table 6 Important trophic factors involved in gut development and the most relevant reference articles
Trophic factor | Ref. | n of references cited |
EGF | Maheshwari (2004)[24] | 36 |
Underwood (2005)[18] | 63 | |
Playford (1996)[29] | 23 | |
Cummins (2002)[15] | 108 | |
HGF | Maheshwari (2004)[24] | 36 |
Underwood (2005)[18] | 63 | |
Cummins (2002)[15] | 108 | |
TGF-α and TGF-β | Maheshwari (2004)[24] | 36 |
Seare (1998)[56] | 32 | |
Underwood (2005)[18] | 63 | |
Cummins (2002)[15] | 108 | |
IGF-1 | Maheshwari (2004)[24] | 36 |
Underwood (2005)[18] | 63 | |
Seare (1998)[56] | 32 | |
Cummins (2002)[15] | 108 | |
Cytokines | Maheshwari (2004)[24] | 36 |
Seare (1998)[56] | 32 |
- Citation: Dasgupta S, Arya S, Choudhary S, Jain SK. Amniotic fluid: Source of trophic factors for the developing intestine. World J Gastrointest Pathophysiol 2016; 7(1): 38-47
- URL: https://www.wjgnet.com/2150-5330/full/v7/i1/38.htm
- DOI: https://dx.doi.org/10.4291/wjgp.v7.i1.38