Open Access Highly Accessed Research article

Effect of hyperinsulinemia during hemodialysis on the insulin-like growth factor system and inflammatory biomarkers: a randomized open-label crossover study

Mark Reinhard1*, Jan Frystyk23, Bente Jespersen1, Mette Bjerre23, Jens S Christiansen23, Allan Flyvbjerg23 and Per Ivarsen1

Author Affiliations

1 Department of Renal Medicine, Aarhus University Hospital and Department of Clinical Medicine, Faculty of Health, Aarhus University, Aarhus, Denmark

2 The Medical Research Laboratory, Department of Clinical Medicine, Faculty of Health, Aarhus University, Aarhus, Denmark

3 Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark

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BMC Nephrology 2013, 14:80  doi:10.1186/1471-2369-14-80

Published: 4 April 2013

Abstract

Background

A marked reduction in serum levels of bioactive insulin-like growth factor-I (IGF-I) has been observed in fasting hemodialysis (HD) patients during a 4-h HD session. The aim of the present study was to investigate the beneficial effect of hyperinsulinemia during HD on bioactive IGF-I and inflammatory biomarkers.

Methods

In a randomized cross-over study, 11 non-diabetic HD patients received a standardised HD session with either: 1) no treatment, 2) glucose infusion (10% glucose, 2.5 mL/kg/h), or 3) glucose-insulin infusion (10% glucose added 30 IU NovoRapid® per litre, 2.5 mL/kg/h). Each experiment consisted of three periods: pre-HD (−120 to 0 min), HD (0 to 240 min), and post-HD (240 to 360 min). A meal was served at baseline (−120 min); infusions were administered from baseline to 240 min. The primary outcome was change in bioactive IGF-I during the experiment. Secondary outcomes were changes in high-sensitivity C-reactive protein, interleukin-1β, interleukin-6, and tumor necrosis factor α. Comparisons were performed using mixed-model analysis of variance for repeated measures.

Results

From baseline to the end of study, no significant differences were observed in the changes in either serum bioactive IGF-I or total IGF-I between study days. Overall, serum bioactive IGF-I levels rose above baseline at 120 to 300 min with a maximum increase of 20% at 120 min (95% confidence interval (CI), 9 to 31%; p < 0.001), whereas total IGF-I levels rose above baseline at 180 to 300 min with a maximum increase of 5% at 240 min (95% CI, 2 to 9%; p = 0.004). A significant difference was observed in the changes in serum IGF-binding protein-1 (IGFBP-1) between study days (p = 0.008), but differences were only significant in the post-HD period. From baseline to the end of HD, no significant difference was observed in the changes in serum IGFBP-1 levels between study days, and in this time period overall serum IGFBP-1 levels were below baseline at all time points with a maximum decrease of 51% at 180 min (95% CI, 45 to 57%; p < 0.001). None of the investigated inflammatory biomarkers showed any differences in the changes over time between study days.

Conclusions

Postprandial insulin secretion stimulated the IGF-system during HD with no further effect of adding glucose or glucose-insulin infusion. Hyperinsulinemia during HD had no effect on biomarkers of inflammation.

Trial registration

ClinicalTrials.gov registry: NCT01209403

Keywords:
Bioactive IGF-I; Hemodialysis; IGFBP-1; Inflammation; Insulin; Nutrition