Glucose ingestion induces an increase in intranuclear nuclear factor kappaB, a fall in cellular inhibitor kappaB, and an increase in tumor necrosis factor alpha messenger RNA by mononuclear cells in healthy human subjects.

Because hyperglycemia is a major detrimental factor in the prognosis of acute cardiovascular conditions such as acute myocardial infarction (AMI) and stroke, and because an acute glucose challenge in healthy subjects has been shown to induce oxidative stress in mononuclear cells (MNCs), we have now investigated whether glucose induces inflammatory stress at the cellular and molecular level. Glucose ingestion (75 g in 300 mL water) in healthy human subjects resulted in an increase in intranuclear nuclear factor kappaB (NF-kappaB) binding, the reduction of inhibitor kappaB alpha (IkappaBalpha) protein, and an increase in the activity of inhibitor kappaB kinase (IKK) and the expression of IKKalpha and IKKbeta, the enzymes that phosphorylate IkappaBalpha, in MNCs. Glucose intake caused an increase in NF-kappaB binding to NF-kappaB2, NF-kappaB2a, and NF-kappaB3 sequences in the promoter site of tumor necrosis factor alpha (TNF-alpha) gene along with an increase in the expression of TNF-alpha messenger RNA in MNCs. Membranous p47(phox) subunit, an index of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase expression and activation, also increased after glucose intake. We conclude that glucose intake induces an immediate increase in intranuclear NF-kappaB binding, a fall in IkappaBalpha, an increase in IKKalpha, IKKbeta, IKK activity, and messenger RNA expression of TNF-alpha in MNCs in healthy subjects. These data are consistent with profound acute pro-inflammatory changes in MNCs after glucose intake.

Increased plasma concentration of macrophage migration inhibitory factor (MIF) and MIF mRNA in mononuclear cells in the obese and the suppressive action of metformin.

The objective of the study was to determine whether plasma migration inhibitor factor (MIF) concentration and mononuclear cell (MNC) mRNA are elevated in obesity and whether treatment with metformin reduces plasma MIF concentration. Forty obese subjects [body mass index (BMI), 37.5 +/- 4.9 kg/m(2)] and 40 nonobese healthy subjects (BMI, 22.6 +/- 3.4 kg/m(2)) had their plasma MIF, glucose, insulin, free fatty acids (FFAs) and C-reactive protein (CRP) concentrations measured. Sixteen obese patients and 16 nonobese healthy subjects had RNA prepared from MNCs. Eight obese subjects with normal glucose concentration were treated with metformin 1 g (Glucophage XR; 1000 mg twice daily) twice daily for 6 wk. Eight obese subjects were used as controls. Plasma concentration of glucose, insulin, FFAs, and MIF was measured by appropriate assays. mRNA for MIF was measured by real-time PCR. Forty obese subjects had a fasting concentration of MIF of 2.8 +/- 2.0 ng/ml, whereas 40 nonobese subjects had a fasting MIF concentration of 1.2 +/- 0.6 ng/ml (P < 0.001). Plasma MIF concentrations were significantly related to BMI (r = 0.52; P < 0.001). mRNA for MIF was correlated to plasma FFAs (r = 0.40; P < 0.05) and plasma CRP (r = 0.42; P < 0.05) concentrations. Eight obese subjects had their fasting blood samples taken before and after taking a slow-release preparation of metformin at 1, 2, 4, and 6 wk. The mean plasma concentration fell from 2.3 +/- 1.4 to 1.6 +/- 1.2 ng/ml at 6 wk (P < 0.05). Obese subjects not on treatment with metformin showed no change. During the period of treatment with metformin, the body weight did not change and the plasma concentration of glucose, insulin, and FFAs did not alter. We conclude that: 1) plasma MIF concentrations and MIF mRNA expression in the MNCs are elevated in the obese, consistent with a proinflammatory state in obesity; 2) these increases in MIF are related to BMI, FFA concentrations, and CRP; 3) metformin suppresses plasma MIF concentrations in the obese, suggestive of an antiinflammatory effect of this drug; and 4) this action of metformin may contribute to a potential antiatherogenic effect, which may have implications for the reduced cardiovascular mortality observed with metformin therapy in type 2 diabetes mellitus.

Circulating mononuclear cells in the obese are in a proinflammatory state.

BACKGROUND: In view of the increase in plasma concentrations of proinflammatory mediators tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and C-reactive protein (CRP) in obesity, we investigated whether peripheral blood mononuclear cells (MNC) from obese subjects are in a proinflammatory state. METHODS AND RESULTS: MNC were prepared from fasting blood samples of obese (n=16; body mass index [BMI]=37.7+/-5.0 kg/m2) and normal-weight control (n=16; BMI=23.8+/-1.9 kg/m2) subjects. Nuclear factor kappaB (NF-kappaB) binding to DNA in nuclear extracts was elevated (P<0.05) and the inhibitor of NFkappaB-beta (IkappaB-beta) was significantly lower (P<0.001) in the obese group. Reverse transcription-polymerase chain reaction revealed elevated levels of migration inhibitor factor (MIF), IL-6, TNF-alpha, and matrix metalloproteinase-9 (MMP-9) mRNA expression in the obese subjects (P<0.05). Plasma concentrations of MIF, IL-6, TNF-alpha, MMP-9, and CRP were also significantly higher. Plasma glucose, insulin, and free fatty acids (FFAs) were measured, and homeostasis model assessment of insulin resistance (HOMA-IR) was calculated. Plasma FFA concentration related significantly to BMI, IL-6, and TNF-alpha mRNA expression and plasma CRP levels but not to HOMA-IR. On the other hand, the inflammatory mediators were significantly related to BMI and HOMA-IR. CONCLUSIONS: These data show (1) for the first time that MNC in obesity are in a proinflammatory state with an increase in intranuclear NF-kappaB binding, a decrease in IkappaB-beta, and an increase in the transcription of proinflammatory genes regulated by NF-kappaB; (2) that plasma FFAs are a modulator of inflammation; and (3) that insulin resistance is a function of inflammatory mediators.

Evidence for a potent antiinflammatory effect of rosiglitazone.

We have recently demonstrated a potent antiinflammatory effect of troglitazone, an agonist of peroxisome proliferator-activated receptor gamma (PPARgamma) and a partial agonist of PPARalpha in both the nondiabetic obese and diabetic obese subjects. We have now investigated the antiinflammatory actions of rosiglitazone, a selective PPARgamma agonist. Eleven nondiabetic obese subjects and 11 obese diabetic subjects were each given 4 mg of rosiglitazone daily for a period of 6 wk. Fasting blood samples were obtained at 0, 1, 2, 4, 6, and 12 wk (6 wk after the cessation of rosiglitazone). Eight obese subjects and five obese diabetic subjects were also included in the study as control groups. Fasting blood samples were obtained from the control groups at 0, 1, 2, 4, and 6 wk only. Nuclear factor kappaB (NFkappaB)-binding activity in mononuclear cells, plasma monocyte chemoattractant protein-1 (MCP-1), TNF-alpha, soluble intercellular adhesion molecule-1, C-reactive protein (CRP), and serum amyloid A (SAA) were measured. Blood glucose concentration changed significantly at 6 wk only in the obese diabetic subjects after rosiglitazone treatment for 6 wk, whereas insulin concentration decreased significantly at 6 wk in both groups. NFkappaB-binding activity in mononuclear cell nuclear extract fell in both obese and obese diabetic subjects (P < 0.02). Rosiglitazone treatment resulted in a reduction in plasma MCP-1 and CRP in both groups (P < 0.05). Plasma TNF-alpha and SAA concentrations were inhibited significantly in the obese group (P < 0.05) but not in the obese diabetic subjects. NFkappaB-binding activity and plasma MCP-1, CRP, SAA, and TNF-alpha did not change in the obese and obese diabetic control groups. We conclude that rosiglitazone, a selective PPARgamma agonist, exerts an antiinflammatory effect at the cellular and molecular level, and in plasma. These observations may have implications for atherogenesis in the long term in subjects treated with rosiglitazone and possibly other thiazolidinediones.