Borrelia burgdorferi Is a Poor Inducer of Gamma Interferon: Amplification Induced by Interleukin-12.

Laboratory diagnosis of Lyme borreliosis (LB) is mainly based on serology, which has limitations, particularly in the early stages of the disease. In recent years there have been conflicting reports concerning a new diagnostic tool using the cytokine interferon-gamma (IFN-γ). Previous studies have generally found low concentrations of IFN-γ in early LB infection. The goal of this study is to investigate IFN-γ regulation during early LB and provide insights into the host response to B. burgdorferi. We performed in vitro experiments with whole blood assays and peripheral blood mononuclear cells (PBMCs) of LB patients and healthy volunteers exposed to B. burgdorferi and evaluated the IFN-γ response using ELISA and related interindividual variation in IFN-γ production to the presence of single nucleotide polymorphisms. IFN-γ production of B. burgdorferi-exposed PBMCs and whole blood was amplified by the addition of interleukin-12 (IL-12) to the stimulation system. This effect was observed after 24 h of B. burgdorferi stimulation in both healthy individuals and LB patients. The effect was highly variable between individuals, but was significantly higher in LB patients 6 weeks since the start of antibiotic treatment compared to healthy individuals. IL-12 p40 and IL-18 mRNA were upregulated upon exposure to B. burgdorferi, whereas IL-12 p35 and IFN-γ mRNA expression remained relatively unchanged. SNP Rs280520 in the downstream IL-12 pathway, Tyrosine Kinase 2, was associated with increased IFN-γ production. This study shows that IL-12 evokes an IFN-γ response in B. burgdorferi exposed cells, and that LB patients and healthy controls respond differently to this stimulation.

Adiponectin multimer distribution in patients with familial combined hyperlipidemia.

Adiponectin is secreted from adipocytes in different multimers, of which the high molecular weight (HMW) form is supposed to mediate favorable metabolic and anti-atherogenic effects. We determined adiponectin multimers in 29 female and 22 male patients with familial combined hyperlipidemia (FCH) and 51 age-, gender-, and BMI-matched controls in relation to cardiovascular disease (CVD). We observed a clear sexual dimorphism of total adiponectin and its multimers. Female, but not male, FCH patients had significant lower total adiponectin and both HMW and low molecular weight (LMW) adiponectin than controls. The adiponectin sensitivity index (ASI), reflected by HMW/total adiponectin, and the LMW/HMW adiponectin ratio did not differ significantly between FCH females and control females. However, FCH females with CVD exhibited significantly lower ASI (34.2+/-10.1% vs 46.0+/-7.1%) and higher LMW/HMW ratio (1.5+/-0.8 vs 0.7+/-0.3) compared to FCH females without CVD, reflecting a more atherogenic adiponectin multimer distribution.

Serum non-transferrin-bound iron and low-density lipoprotein oxidation in heterozygous hemochromatosis.

UNLABELLED: Non-transferrin-bound iron (NTBI) is implicated in lipid peroxidation but the relation with oxidative modification of low-density lipoprotein (LDL) is not known. We assessed variables reflecting in vitro and in vivo LDL oxidation in two age- and sex-matched groups (n=23) of hereditary hemochromatosis heterozygotes (C282Y), characterized by a clear difference in mean serum NTBI (1.55+/-0.57 micromol/L vs 3.70+/-0.96 micromol/L). Plasma level of oxidized LDL (absolute and relative to plasma apolipoprotein B), and IgG and IgM antibodies to oxidized LDL, markers of in vivo LDL oxidation, did not differ between the groups with low and high serum NTBI. Mean lag-phase of in vitro LDL oxidation was also not significantly different between both study groups. CONCLUSION: these findings do not support the hypothesis that NTBI promotes oxidative modification of plasma LDL.

Low plasma levels of oxidized low density lipoprotein in preeclampsia.

BACKGROUND: Markers of lipid peroxidation are commonly used to assess oxidative stress in preeclampsia. The aim of this study was to assess the concentration of oxidized low density lipoprotein (oxLDL), a novel marker for lipid peroxidation, and that of the thiobarbituric acid reactive substances (TBARS) in the pathogenesis of severe preeclampsia and to investigate the influence of gestational age on these parameters. METHOD: Plasma levels of oxLDL and TBARS were assayed in women with severe preeclampsia (n = 40), normotensive pregnant controls matched for gestational age (n = 24) and normotensive pregnant controls at full term (n = 16). RESULTS: Women with preeclampsia showed lower oxLDL levels (mean +/- SE) than matched controls (181 +/- 12 vs. 219 +/- 14; p = 0.027), whereas no differences were found for the TBARS concentration (3.8 +/- 0.6 vs. 3.7 +/- 0.4). When women with preeclampsia were compared to control women at full term, TBARS were elevated (3.8 +/- 0.6 vs. 1.5 +/- 0.2; p = 0.01). However, in women with normotensive pregnancy TBARS were also lower in full-term control pregnancy compared to early third-trimester values (p < 0.0001). CONCLUSION: Plasma TBARS decreased during the third trimester of pregnancy, underlining the importance of matching for gestational age when studying markers of lipid peroxidation in pregnant women. Women with preeclampsia had lower plasma levels of oxLDL compared to gestational age-matched controls, indicating that oxLDL could be a marker for preeclampsia.

Neutrophil superoxide-anion generating capacity in chronic smoking: effect of long-term alpha-tocopherol therapy.

We investigated whether long-term alpha-tocopherol therapy in chronic smoking affects superoxide generating capacity of neutrophils ex vivo. To this purpose, we randomly assigned 128 male chronic smokers (37 +/- 21 pack years of smoking) to treatment with placebo (n = 64) or alpha-tocopherol (400 IU dL-a-tocopherol daily, n = 64). After two years of therapy, we measured phorbol 12-myristate 13-acetate-induced superoxide production of isolated neutrophils and of diluted whole blood by monitoring reduction of ferricytochrome c and luminol-enhanced peroxidase-catalyzed chemiluminescence. Plasma lipids and lipoproteins were not different between the two treatment groups. As expected, concentrations of alpha-tocopherol in plasma and in low-density lipoproteins were markedly elevated in the supplemented group compared to the placebo group (+ 120%, P < 0.0001 and + 83%, P < 0.0001, respectively). Consequently, resistance to in vitro oxidation of low-density lipoproteins (reflected by lag time of conjugated diene formation) was higher in the supplemented group than in the placebo group (+ 22%, P < 0.0001). Superoxide generating capacity of neutrophils and superoxide production in diluted whole blood did not differ between alpha-tocopherol and placebo group. It is concluded that in chronic smoking long-term supranormal alpha-tocopherol intake does not reduce neutrophil superoxide-anion generating capacity, despite large increases in the concentrations of alpha-tocopherol in plasma and in low-density lipoproteins.