Reduction in circulating IGF-I and hepatic IGF-I mRNA levels after caecal ligation and puncture are associated with differential regulation of hepatic IGF-binding protein-1, -2 and -3 mRNA levels.
Sepsis is characterized by a severe shift in metabolism, characterized by low IGF-I levels. We have studied the influence of caecal ligation and puncture (CLP) on the levels of circulating IGF-I and hepatic IGF-I and IGF-binding protein (IGFBP)-1, -2 and -3 mRNA in adult male Wistar rats (n = 12) and compared it with sham-operated rats (n = 6). In order to exclude anorexia-induced changes we also studied animals pair-fed to both groups. IGF-I levels were measured by RIA. Steady-state hepatic IGF-I, IGFBP-1, IGFBP-2 and IGFBP-3 mRNA levels were measured by Northern blot analysis using specific rat cDNA probes. Food intake averaged 13.0 +/- 2.0 g/day in the sham-operated rats fed ad libitum during the study period, with a sharp decline in food intake in the CLP animals (2.3 +/- 1.3 g/day). After CLP, there was a significant reduction in circulating IGF-I levels (467.2 +/- 50.9 micrograms/l) compared with sham-operated animals (924.0 +/- 75.3 micrograms/l; P = 0.04) or those pair-fed to the CLP rats (612.5 +/- 52.9 micrograms/l; P = 0.04). Total hepatic IGF-I mRNA levels were significantly reduced (2.57 +/- 0.05 densitometric units (DU) after CLP compared with the sham-operated group (2.71 +/- 0.04); P = 0.04), or their pair-fed controls (2.75 +/- 0.08 DU; P < 0.05). Hepatic IGFBP-3 mRNA levels were lower after CLP (0.37 +/- 0.04 DU) than in the sham-operated animals (0.66 +/- 0.09 DU; P = 0.04) or their pair-fed controls (0.61 +/- 0.05 DU; P = 0.04). On the other hand, hepatic IGFBP-2 mRNA levels were increased after CLP (0.91 +/- 0.11 DU) compared with sham-operated animals (0.28 +/- 0.06 DU; P = 0.01) or with their pair-fed controls (0.22 +/- 0.02; P = 0.01), as were hepatic IGFBP-1 mRNA levels (CLP animals 0.95 +/- 0.11 DU; sham-operated 0.30 +/- 0.04 DU, P = 0.01; pair-fed 0.30 +/- 0.02 DU, P = 0.01). No significant difference between sham-operated animals and their pair-fed controls was observed in circulating IGF-I levels (888.0 +/- 109.3 micrograms/l; P = not significant (N.S.)), hepatic mRNA levels for IGF-I (2.72 +/- 0.06 DU; P = N.S), IGFBP-3 (0.71 +/- 0.07 DU; P = N.S.), IGFBP-2 (0.25 +/- 0.07 DU; P = N.S.) or IGFBP-1 (0.27 +/- 0.06 DU; P = N.S.). In summary, after CLP there was a reduction in both circulating and hepatic IGF-I mRNA levels associated with a specific and differential regulation of hepatic IGFBP-1, -2 and -3 mRNA levels. Although we cannot eliminate a possible effect of surgical stress combined with malnutrition, our results suggest that these changes are a specific effect of sepsis rather than simply a result of surgical stress or poor nutrition alone.
Rodríguez-Arnao
J
J
Department of Endocrinology, St Bartholomew's Hospital, London, UK.
Yarwood
G
G
Ferguson
C
C
Miell
J
J
Hinds
C J
CJ
Ross
R J
RJ
D000818:Animals; D001424:Bacterial Infections / Q000378:metabolism*; D015152:Blotting, Northern; D002429:Cecal Diseases / Q000378:metabolism*; D005786:Gene Expression Regulation; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000235:genetics; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000235:genetics; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000235:genetics; D018969:Insulin-Like Growth Factor Binding Proteins / Q000235:genetics*; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D018970:Insulin-Like Growth Factor Binding Protein 1; D018971:Insulin-Like Growth Factor Binding Protein 2; D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I