Perinatal and postweaning exposure to galactooligosaccharides/inulin prebiotics induced biomarkers linked to tolerance mechanism in a mouse model of strong allergic sensitization.

Food allergies are increasing, and no treatment exists, thus enhancing interest in prebiotic strategies. This study aimed to analyze the preventive effects of prebiotic feeding during perinatal and postweaning periods in a mouse model of allergy by studying biomarkers related to tolerance (IgG2a, IgA, IFN-γ, TGF-ß, and IL-10), to allergy (IgE, IgG1, IL-4, IL-17, symptoms), and to microbiota (propionate and MyD88). Balb/c mice, both dams and their pups, were fed a diet supplemented with (+Prb) or without (-Prb) GOS/inulin prebiotics. Mice were then sensitized with allergens. Regardless of diet, sensitized mice exhibited similar levels of IgE, IgG1, CD-23, IL-4, IL-17, and symptoms. However, in comparison to -Prb-sensitized mice, +Prb-sensitized mice displayed higher concentrations of total IgG2a (6669 ± 1788 vs 3696 ± 1326 fluorescence units, p < 0.005), specific IgA (285 ± 26 vs 156 ± 9 fluorescence units, p < 0.01), IFN-γ (3194 ± 424 vs 1853 ± 434 pg/mL, p < 0.01), IL-10 (777 ± 87 vs 95 ± 136 pg/mL, p < 0.005), TGF-ß (4853 ± 1959 vs 243 ± 444 pg/mL, p < 0.01), MyD88 (0.033 ± 0.019 vs 0.009 ± 0.004 relative expression, p < 0.01), and propionate (4.15 ± 0.8 vs 2.9 ± 1.15 µmol, p < 0.05). In a mouse model of allergy, prebiotic exposure during perinatal and postweaning periods induced the highest expression of biomarkers related to tolerance without affecting biomarkers related to allergy.

Exposure to a galactooligosaccharides/inulin prebiotic mix at different developmental time points differentially modulates immune responses in mice.

Prebiotics constitute emerging tools to alleviate immune pathologies. This study aimed to evaluate the effect of prebiotic exposure during perinatal and postweaning periods on immune and gut regulations. Mice were fed either a galactooligosaccharides/inulin prebiotic mix-enriched diet or a control diet during the perinatal and/or postweaning periods. Biomarkers related to gut barrier function (SCFA, heat shock proteins, zonula occludens protein-1, and mucin-2) and immune mechanisms (IgA, IgE, IgG1, IgG2a, IL-10, TGF-ß, IL-4, IL-17A, and IFN-γ) were analyzed. The milk of dams fed the prebiotic diet was more concentrated in both IgA and TGF-ß when prebiotics were introduced during both the perinatal and postweaning periods; IL-10, IgA, and IgG2a were increased in pups; and expression of intestinal markers was more pronounced. Postweaning exposure to prebiotics alone induced higher INF-γ and TGF-ß levels, whereas IgA levels fell. Combined exposure periods (perinatal/postweaning) to prebiotics increased tolerance-related immunoglobulins in pups and reinforced gut barrier functions.

Impact of perinatal prebiotic consumption on gestating mice and their offspring: a preliminary report.

To assess the impact of prebiotic supplementation during gestation and fetal and early neonatal life, gestating BALB/cj dam mice were fed either a control or a prebiotic (galacto-oligosaccharides-inulin, 9:1 ratio)-enriched diet throughout pregnancy and lactation, and allowed to nurse their pups until weaning. At the time of weaning, male offspring mice were separated from their mothers, weaned to the same solid diet as their dam and their growth was monitored until killed 48 d after weaning. Prebiotic treatment affected neither the body-weight gain nor the food intake of pregnant mice. In contrast, at the time of weaning, pups that had been nursed by prebiotic-fed dams had a higher body weight (11.0 (se 1.2) g) than pups born from control dams (9.8 (se 0.9) g). At 48 d after weaning, significantly higher values were observed for colon length and muscle mass in the offspring of prebiotic-fed dams (1.2 (se 0.1) cm/cm and 5.7 (se 1.8) mg/g, respectively), compared with control offspring (1.1 (se 0.1) cm/cm and 2.9 (se 0.9) mg/g, respectively), without any difference in spleen and stomach weight, or serum leptin concentration. The present preliminary study suggests that altering the fibre content of the maternal diet during both pregnancy and lactation enhances offspring growth, through an effect on intestinal and muscle mass rather than fat mass accretion.

Evaluation of the sensitivity of an in vitro high frequency ultrasound device to monitor the coagulation process: study of the effects of heparin treatment in a murine model.

This study evaluates the sensitivity of a new in vitro high frequency ultrasound test of the whole blood coagulation process. A rat model of anticoagulant treatment is reported. Many recent studies of the role of red blood cells in the whole blood coagulation process have revealed an increasing demand for global tests of the coagulation process performed on whole blood instead of plasma samples. In contrast to existing optical tests, high frequency ultrasound presents the advantages of characterizing the mechanical properties of whole blood clotting. Ultrasound longitudinal wave velocity and integrated attenuation coefficient (IAC) were simultaneously assessed in a 10 to 30 MHz frequency range during the whole blood coagulation process in vitro in rats under anticoagulant therapy. Differences between humans and rats were also clearly emphasized in non-clotting blood and in clotting blood using specific criteria deduced from acoustic parameters (ultrasound velocity for non-clotting blood:=1574+/-2m/s for rats and 1583+/-3m/s for humans and IAC=2.25+/-0.14 dB/cm for rats and 1.5+/-0.23 dB/cm for humans). We also measured the coagulation time t(0) from the acoustic velocity (t(0) =11.15+/-7 min for control rat blood and 43.3+/-11.4 min for human blood). Different doses of heparin were administered to rats. The sensitivity of the ultrasound device to the effects of heparin was evaluated. Differences between non-treated rats and chronically and acutely treated rats were recorded and quantified. We particularly noted that the slope S and the amplitude I of the variations in acoustic velocity were linked to clot retraction, which is a good indicator of the platelet function. The amplitude of the variations in S was between (20+/-8) x1 0(-3) m/s(2) for control group rats, and (0.92+/-0.35) x 10(-3) m/s(2) for chronic heparin-treated group rats. The values of I were 15 times higher for control group rats than for chronic heparin-treated group rats.

Heme oxygenase-1 inducer hemin attenuates the progression of remnant kidney model.

BACKGROUNDS/AIMS: Heme oxygenase-1 (HO-1) has been shown to protect against fibrotic proliferation and apoptosis in several models of renal damage. The purpose of this study was to evaluate the impact of a treatment with the HO-1 inducer hemin on the progression of chronic kidney disease in nephrectomized rats versus the AT1 receptor antagonist losartan. METHODS: The rats underwent 5/6 renal ablation and after the procedure received either losartan (20 mg/kg/day; n = 9), hemin (50 mg/kg/twice a week; n = 8) or vehicle (n = 8) over a 12-week period. At week 12, blood pressure was measured, urine, blood and remnant kidney were collected for biochemical (proteinuria, urea, creatinine) and histopathological (degrees of glomerulosclerosis and tubular atrophy) analysis. The expressions of HO-1, bone morphogenic protein 7 (BMP-7) and TGF-beta were assessed by immunochemistry, and the level of the apoptosis marker protein caspase-3 by Western blot, on the remnant kidney. RESULTS: Hemin significantly reduced blood pressure, proteinuria, inhibited the expression of TGF-beta and caspase-3 protein and increased BMP-7 expression protein. Hemin-treated rats had lower glomerulosclerosis and tubular atrophy indexes than controls. CONCLUSION: Hemin treatment attenuates the progression of chronic kidney disease and appears more efficient than losartan in our rat model hypothetically because of the impact of hemin on the renal expression of BMP-7.

Dexfenfluramine discontinuous treatment does not worsen hypoxia-induced pulmonary vascular remodeling but activates RhoA/ROCK pathway: consequences on pulmonary hypertension.

The anorectic drug, dexfenfluramine has been associated with an increase in the relative risk of developing pulmonary hypertension. 5-hydroxytryptamine (5-HT) is a mitogen for smooth muscle cell, an effect that relies on 5-HT transporter expression and which has been proposed to explain pulmonary side effect of dexfenfluramine, and more particularly its effect on vascular remodeling. However recent data supported a major role of pulmonary artery vasoconstriction through the RhoA/Rho-kinase pathway. We questioned whether or not anorectic treatment aggravates pulmonary hypertension through vascular remodeling and if RhoA/Rho-kinase (ROCK) was potentially involved. In rats exposed to hypoxia, concomitant dexfenfluramine treatment (5 mg/kg/day, i.v.) for 4 weeks had no effect on pulmonary hypertension development. When exposure to 2 weeks of chronic hypoxia followed discontinuation of dexfenfluramine treatment (dexfenfluramine-hypoxic rats), echocardiographic parameters of pulmonary artery flow and right ventricle were further altered (P<0.05) as well as right ventricle systolic pressure was further increased (P<0.001) when compared to hypoxic rats treated with vehicle (hypoxic rats). However, the total number of muscularized distal pulmonary arteries artery was similar in dexfenfluramine-hypoxic vs. hypoxic rats (P>0.05). Western blot, RT-PCR and immunofluorescence analysis revealed a greater expression of 5-HT transporter and ROCK, as well as a greater activation of RhoA in dexfenfluramine-hypoxic rats compared to hypoxic rats. These data show that increased 5-HT transporter expression that follows dexfenfluramine discontinuation is not associated to a greater vascular remodeling despite worsening the development of pulmonary hypertension. Furthermore dexfenfluramine discontinuation promotes a greater RhoA/ROCK pathway activation. This pathway, involved in many cardiovascular diseases, might explain the cardiac and pulmonary toxicity of serotoninergic agonists.

Effect of the heme oxygenase inducer hemin on blood haemostasis measured by high-frequency ultrasound.

1. Heme compounds, like hemin, a heme oxygenase-1 inducer, are used in the treatment of acute porphyria treatment. The side-effects of hemin on haemostasis have been reported. To address those effects, in the present study we used a sensitive, high-frequency ultrasound technique to record acoustic velocity and to investigate whole blood clotting in Wistar rats treated chronically with hemin (50 mg/kg per day). 2. The hemin-induced disturbances in haemostasis measured were comparable to the heparin reference treatment, with a significant decrease in clotting velocity in both groups compared with controls (e.g. the time to clot was 40 +/- 5, 53 +/- 13 and 10 +/- 2 min, respectively; P < 0.05). Precautions must be taken when using high doses of hemin or in the treatment of bleeding diseases. 3. Further investigations are required to explore the effects of hemin in thrombosis models, because it could be a promising 'old drug' for the treatment of venous thrombosis in patients.

Heme oxygenase-1 inducer hemin prevents vascular thrombosis.

Hemin is a heme oxygenase-1 (HO-1) inducer which provides endogenous carbon monoxide known for playing roles in cell proliferation, inflammation or aggregation process. The objective of the current study was to examine the effect of prophylactic treatment with hemin in a thrombosis vascular model. Three groups of Wistar rats, control (n = 6), hemin (n = 6) and hemin + HO-1 inhibitor (n = 6), were used for this study. Hemin-treated animals received hemin (50 mg/kg/d; I.P.) for seven days and HO-1 inhibitor group received hemin at the same dose and SnPP IX (60 mg/kg/d; I.P.). All animals were exposed to electric stimulation of the left carotid according to Kawasaki's procedure to induce reproducible thrombus formation. The hemin treatment did not induce blood pressure disturbance. Effects of hemin on vascular thrombosis were quantified by histopathology and its influence on haemostasis was assessed by measuring prothrombin time (PT), activated partial thromboplastin time (APTT) and blood parameters at the end of treatment. The HO-1 mRNA and protein level variation were also checked out. Results showed that chronic treatment with hemin significantly (p < 0.01) reduced the vascular occlusion degree when compared to control and hemin SnPP groups with 7.2 +/- 4.6 vs. 71.1 +/- 14.7 and 74.0 +/- 8.8%, respectively. Moreover, we observed significant (p < 0.05) perturbations of blood parameters in hemin-treated and hemin-SnPP treated rats. Interestingly, hemin treatment did not significantly increase both PT and APTT. Finally, the HO-1 mRNA and protein levels were increased in hemin-treated carotid artery. In conclusion, hemin by inducing HO-1 expression may be a preventive agent against clinical disorders associated to an increased risk of thrombosis events and may limit haemorrhagic risks.