Blood levels of pro-inflammatory and anti-inflammatory cytokines during an oral glucose tolerance test in patients with symptoms suggesting reactive hypoglycemia

ABSTRACT

We evaluated the impact of postprandial glycemia on blood levels of pro-inflammatory and anti-inflammatory cytokines during an oral glucose tolerance test in non-diabetic patients with symptoms suggesting reactive hypoglycemia. Eleven patients with clinical symptoms suggesting reactive hypoglycemia received an oral glucose solution (75 g) Blood was collected at 0 (baseline), 30, 60, 120 and 180 min after glucose ingestion and the plasma concentrations of interferon-α (IFN-α), interferon-γ (IFN-γ), interleukin-1 receptor antagonist (IL-1RA), interleukin 2 (IL-2), interleukin-2 receptor (IL-2R), interleukin 4 (IL-4), interleukin 6 (IL-6), interleukin 8 (IL-8), interleukin 10 (IL-10), interleukin-12 (IL-12), interleukin 13 (IL-13), interleukin 15 (IL-15), interleukin 17 (IL-17), IFN-γ inducible protein 10 (IP-10), monocyte chemotactic protein 1 (MCP1), monokine induced by IFN-γ (MIG), macrophage inflammatory protein-1α (MIP-1α), interleukin-1β (IL-1β), colony stimulating factor (G-CSF), granulocyte-macrophage CSF (GM-CSF), basic fibroblast growth factor (FGF-basic), eotaxin, tumor necrosis factor α (TNFα), epidermal growth factor (EGF), hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF), macrophage inflammatory protein-1α (MIP-1α), and 1β (MIP-1β) were evaluated. Overall, glycemic levels increased, reached its maximum at 30 min (phase 1), returned to baseline levels at 120 min (phase 2), followed by a mild hypoglycemia at 180 min (phase 3). During phase 1, cytokine blood levels were maintained. However, we observed a synchronous fall (P<0.05) in the concentrations of pro-inflammatory (IL-15, IL-17, MCP-1) and anti-inflammatory cytokines (FGF-basic, IL-13, IL-1RA) during phase 2. Furthermore, a simultaneous rise (P<0.05) of pro-inflammatory (IL-2, IL-5, IL-17) and anti-inflammatory cytokines (IL-4, IL-1RA, IL-2R, IL-13, FGF-basic) occurred during phase 3. Thus, mild acute hypoglycemia but not a physiological increase of glycemia was associated with increased blood levels of anti-inflammatory and pro-inflammatory cytokines.