Insulin-Like Growth Factor 1: A Valid Nutritional Indicator during Parenteral Feeding of Patients Suffering an Acute Phase Response

Abstract

Insulin-like growth factor 1 (IGF-1) is regulated by nutritional intake independently of growth hormone and may be a better nutritional indicator than the plasma proteins. This possibility was investigated in six malnourished inpatients, who suffered sepsis, surgical trauma, or both and who received total parenteral nutrition (TPN) for 10−35 days. Both plasma IGF-1 and pre-albumin showed (P < 0·05) increases during TPN from baseline values of 0·042−0·42 U/mL (median, 0·11) and 59−156 mg/L (median, 108), respectively, to maxima of 0·19–1·12 U/mL (median, 0·63) and 140–363 mg/L (median, 203). Statistically significant (P < 0·05) positive correlation occurred between nitrogen balance (range, −7·5 to + 11·0 g/day) and IGF-1 or pre-albumin. Correlation between nitrogen balance and IGF-1 is preserved during the acute phase response to tissue injury when C-reactive protein (CRP) varies in the range 40–248 mg/L. Under these circumstances, the correlation between nitrogen balance and pre-albumin is, in contrast, abolished. These results suggest that IGF-1 behaves as a valid index of nutritional adequacy during parenteral feeding whereas pre-albumin reflects mainly the acute phase response.