Serum Levels Of Leukotriene B4 Research Articles

Leukotriene B4: A potential mediator and biomarker for cardiac allograft vasculopathy

BackgroundCardiac allograft vasculopathy (CAV) remains the leading cause of long-term graft failure and mortality after heart transplantation. Effective preventive and treatment options are not available to-date, largely because underlying mechanisms remain poorly understood. We studied the potential role of leukotriene B4 (LTB4), an inflammatory lipid mediator, in development of CAV. MethodsWe used an established pre-clinical rat CAV model to study the role of LTB4 in CAV. We performed syngeneic and allogeneic orthotopic aortic transplantation, after which neointimal proliferation was quantified. Animals were then treated with Bestatin, an inhibitor of LTB4 synthesis, or vehicle control for 30 days post-transplant, and evidence of graft CAV was determined by histology. We also measured serial LTB4 levels in a cohort of 28 human heart transplant recipients with CAV, 17 matched transplant controls without CAV, and 20 healthy non-transplant controls. ResultsWe showed that infiltration of the arterial wall with macrophages leads to neointimal thickening and a rise in serum LTB4 levels in our rat model of CAV. Inhibition of LTB4 production with the drug Bestatin prevents development of neointimal hyperplasia, suggesting that Bestatin may be effective therapy for CAV prevention. In a parallel study of heart transplant recipients, we found non-significantly elevated plasma LTB4 levels in patients with CAV, compared to patients without CAV and healthy, non-transplant controls. ConclusionsThis study provides key evidence supporting the role of the inflammatory cytokine LTB4 as an important mediator of CAV development, and provides preliminary data suggesting the clinical benefit of Bestatin for CAV prevention.

Imbalanced serum levels of resolvin E1 (RvE1) and leukotriene B4 (LTB4) may contribute to the pathogenesis of atherosclerosis

Persistent and chronic unresolved inflammation exerts a critical role in developing atherosclerosis; however, mechanisms that prevent the resolution of inflammation in atherosclerosis are poorly delineated. This study aims to evaluate the serum levels of inflammatory high-sensitivity C-reactive protein (hsCRP), pro-inflammatory leukotriene B4 (LTB4), besides anti-inflammatory compounds, including eicosapentaenoic acid (EPA) and its derivative resolvin E1 (RvE1) in patients with atherosclerosis. Thirty-four atherosclerosis patients and thirty-two age- and sex-matched healthy individuals were included in this study. The serum levels of hsCRP, LTB4, EPA, and RvE1 were measured using the enzyme-linked immunosorbent assay (ELISA) technique. Our results showed that the hsCRP serum levels in the three-vessel disease (3VD) subgroup of patients are significantly lower than those in the mild and single-vessel disease (SVD) subgroups (P < 0.05). Besides, the serum levels of LTB4 were meaningfully greater in patients with atherosclerosis compared to healthy controls (P < 0.05). Also, the serum EPA and RvE1 levels were significantly higher in patients than in controls (P < 0.01 and P < 0.05, respectively). However, the ratio of RvE1 to LTB4 (RvE1:LTB4) in patients was significantly reduced to that in controls (P < 0.0001). These findings illustrate that imbalanced pro-resolving RvE1 and pro-inflammatory LTB4 might contribute to failing vascular inflammation resolution and subsequent progression toward chronic inflammation in atherosclerosis.

Effect of halometasone cream combined with Simiao pill on the therapeutic effect and expression of serum leukotriene B4 (LTB4) and thymic stromal lymphopoietin (TSLP) in patients with eczema, and the factors influencing its clinical efficacy.

Chronic eczema has the characteristics of a long treatment cycle and repeated attacks, which seriously affects the daily life and work of patients. Topical glucocorticoids are the first-line treatment for chronic eczema. This study aimed to retrospectively analyze the effects of halometasone cream combined with Simiao pill on the efficacy and expression of serum leukotriene B4 (LTB4) and thymic stromal lymphopoietin (TSLP) in patients with eczema, and identify the factors influencing its clinical efficacy. We retrospectively collected the medical records of 195 patients with chronic eczema treated in the dermatology department from January 2020 to May 2021, and divided them into two groups according to medication: 98 cases were treated with halometasone cream (control group) and 97 cases were treated with halometasone ointment combined with Simiao pill (observation group). The severity of eczema, quality of life, clinical efficacy, LTB4 and TSLP levels, and safety were compared between the two groups. Multivariate logistic regression analysis was used to determine the independent factors affecting clinical efficacy. After treatment, the Eczema area and severity index (EASI) and Dermatology Life Quality Index (DLQI) scores in the observation group were markedly lower than those of the control group (P<0.05). The total clinical effective rate of the observation group was 88.8%, which was notably higher than that of the control group 70.1% (P=0.001). The concentrations of serum LTB4 and TSLP in the observation group were markedly lower than those in the control group (P<0.05). Logistic regression analysis showed that the treatment regimen, digestive system symptoms, heavy aching limbs, and damp-heat tongue and pulse were independent factors affecting the curative effect of the patients (P<0.05). Simiao pill combined with halometasone cream can effectively improve chronic eczema and enhance the clinical efficacy of treatment, which may be related to the reduction of serum LTB4 and TSLP levels. The treatment plan, digestive system symptoms, heavy aching limbs, and damp-heat tongue and pulse are the main factors that affecting the clinical curative effect. Thus, clinical intervention programs should be made according to the above factors to improve the quality of life of patients.

High leukotriene B4 serum levels increase risk of painful diabetic neuropathy among type 2 diabetes mellitus patients

BackgroundPainful diabetic neuropathy is one of the most common complications of type 2 diabetes mellitus, with approximately 30–50% of people will experience diabetic neuropathy. Chronic hyperglycemia will cause an inflammatory process that will trigger an immune response included leukotrienes. Leukotriene B4 is associated with hemoglobin glycation levels. This study aimed to determine high serum leukotriene B4 levels and other factors as a risk factor for painful diabetic neuropathy in type 2 diabetes mellitus patient.ResultsForty-two subjects with 22 cases (median age 56.5 ± 4.9 years) and 20 controls (median age 56.5 ± 5.2 years) group were collected. In bivariate analysis, significant factor for high risk PDN was high leukotriene B4 serum level (OR 5.10; 95% CI 1.34–19.4, p 0.014). Meanwhile, insignificant factors were anti-diabetic drugs (OR 2.139; 0.62–7.37; p = 0.226), and duration of diabetes mellitus (OR 2.282; 0.56–9.25; p = 0.315). Independent risk factor was serum leukotriene B4 levels (OR 5.10; 95% CI 1.336–19.470; p = 0.017).ConclusionsIn this study, high leukotriene B4 serum levels increase the risk of painful diabetic neuropathy among type 2 diabetes mellitus. The leukotriene B4 may consider as a potential biomarker for early detection in high risk for PDN and early treatment.

Anti-inflammatory activity of palmitoylethanolamide ameliorates osteoarthritis induced by monosodium iodoacetate in Sprague\u2013Dawley rats

Novel treatment strategies are urgently required for osteoarthritis (OA). Palmitoylethanolamide (PEA) is a naturally occurring fatty acid amide with analgesic and anti-inflammatory effects. We aimed to examine its effect on OA and elucidate the molecular mechanism of actions in monosodium iodoacetate (MIA)-induced OA Sprague–Dawley rats. The experimental animals were divided into normal control group (injected with saline + treated with phosphate-buffered saline (PBS), NOR), control group (injected with MIA + treated with PBS, CON), 50 or 100 mg/kg body weight (BW)/day PEA-treated group (injected with MIA + treated with 50 or 100 mg of PEA/kg BW/day, PEA50 or PEA100), and positive control group (injected with MIA + treated with 6 mg of diclofenac/kg BW/day, DiC). The changes in blood parameters, body parameters, gene expression of inflammatory mediators and cytokines, knee thickness, and joint tissue were observed. Oral administration of PEA had no adverse effects on the BW, liver, or kidneys. PEA reduced knee joint swelling and cartilage degradation in MIA-induced OA rats. The serum levels of leukotriene B4, nitric oxide, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and prostaglandin E2 considerably reduced in the PEA100 group compared with those in the CON group. In the synovia of knee joints, the mRNA expression of iNOS, 5-Lox, Cox-2, Il-1β, Tnf-α, and Mmp-2, -3, -9, and -13 apparently increased with MIA administration. Meanwhile, Timp-1 mRNA expression apparently decreased in the CON group but increased to the normal level with PEA treatment. Thus, PEA can be an effective therapeutic agent for OA.

Imbalanced serum levels of resolvin E1 (RvE1) and leukotriene B4 (LTB4) in patients with allergic rhinitis

Timely and successful resolution of acute inflammation plays a crucial role in preventing the development of chronic airway inflammation in allergic rhinitis (AR). This study intends to assess the serum levels of pro-inflammatory leukotriene B4 (LTB4), anti-inflammatory mediators, including resolvin E1 (RvE1), RvD1, IL-10, and TGF-β, besides mRNA expression level of G-protein coupled receptor 120 (GPR120) and peroxisome proliferator-activated receptor-γ (PPAR-γ) receptors in peripheral blood leukocytes of AR patients. Thirty-seven AR patients and thirty age- and gender-matched healthy subjects were enrolled in this study. The serum levels of LTB4, RvE1, RvD1, IL-10, and TGF-β were measured using enzyme-linked immunosorbent assay (ELISA) technique, and the mRNA expression level of GPR120 and PPAR-γ was assessed by the real-time PCR method. The serum levels of RvE1 and LTB4 were significantly higher in patients with AR than in healthy subjects (P < 0.01 and P < 0.0001, respectively). However, a significantly lower ratio of RvE1 and RvD1 to LTB4 was found in patients with AR relative to healthy subjects (P < 0.05 and P < 0.0001, respectively). Likewise, the serum levels of both IL-10 and TGF-β cytokines were significantly reduced in patients with AR compared to healthy subjects (P < 0.01 and P < 0.0001, respectively). Furthermore, the mRNA expression of PPAR-γ was significantly lower in patients with AR than in healthy subjects (P < 0.05). Our findings indicate that imbalanced pro-resolving lipid mediator RvE1 and pro-inflammatory LTB4 might contribute to the defective airway inflammation-resolution and subsequent progression toward chronic inflammation in AR patients.

Promotion of Myofibroblast Differentiation and Tissue Fibrosis by the Leukotriene B4 -Leukotriene B4 Receptor Axis in Systemic Sclerosis.

To investigate the role of the inflammatory lipid mediator leukotriene B4 (LTB4 ) and its receptor, BLT1, in the development and progression of systemic sclerosis (SSc). Serum levels of LTB4 were compared in 64 patients with SSc and 80 healthy controls. Skin and lung tissue sections from patients with SSc and healthy donors were immunostained for leukotriene A4 hydrolase (LTA4 H), the critical enzyme for LTB4 synthesis, and BLT1, in combination with different cell markers. In mouse models of SSc using bleomycin or angiotensin II challenge or immunization with the DNA topoisomerase I, genetic or pharmacologic interruption of the LTB4 -BLT1 axis in mice was carried out to assess its effects on systemic disease features and myofibroblast markers. Immunoblotting was performed to examine the signaling pathway in fibroblasts and endothelial cells following stimulation with LTB4 or with serum from SSc patients. Serum LTB4 levels were 44.93% higher in patients with SSc than in matched healthy controls (mean ± SD 220.3 ± 74.75 pg/ml versus 152.0 ± 68.05 pg/ml; P < 0.0001), and this was associated with the patient subsets of SSc-associated interstitial lung disease and diffuse cutaneous SSc. Levels of LTA4 H and BLT1 were increased in lesional areas of the skin and lungs of SSc patients, and both were abundant in myofibroblasts and endothelial cells. Interruption of the LTB4 -BLT1 axis in mouse models of SSc significantly mitigated dermal and pulmonary fibrosis, with 54.00% and 52.65% fewer α-smooth muscle actin-positive myofibroblasts accumulating in the skin and lungs of mice, respectively, after bleomycin challenge. Immunoblotting of cultures with recombinant LTB4 -stimulated fibroblasts and endothelial cells or with serum from SSc patients showed that fibroblast-myofibroblast and endothelial-mesenchymal transitions were promoted via BLT1, and that this was dependent on activation of the phosphatidylinositol 3-kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR) pathway but independent of the release of transforming growth factor β (TGFβ) by fibroblasts or endothelial cells. The LTB4 -BLT1 axis may contribute to fibrosis in SSc by directly promoting myofibroblast differentiation via the PI3K/Akt/mTOR pathway, and this appears to operate independently of autocrine secretion of TGFβ.

Serum leukotriene B4 levels, tonsillar hypertrophy and sleep-disordered breathing in childhood

ObjectivesIn children with snoring, increased production of leukotriene B4 (LTB4) may promote tonsillar hypertrophy and sleep-disordered breathing (SDB) or conversely SDB may enhance LTB4 synthesis. We explored whether: i) high LTB4 serum levels predict tonsillar hypertrophy; and ii) SDB severity correlates with LTB4 serum concentration. MethodsNormal-weight children with SDB or controls underwent polysomnography and measurement of LTB4 serum concentration. Tonsillar hypertrophy was the main outcome measure and high LTB4 serum level (>75 t h percentile value in controls) was the primary explanatory variable. Odds ratio (OR) and the corresponding 95% confidence intervals (CI) for tonsillar hypertrophy in children with versus without high LTB4 level were calculated. The control subgroup and subgroups of subjects with increasing SDB severity were compared regarding LTB4 concentration by Kruskal-Wallis test. Spearman's correlation co-efficient was applied to assess the association of LTB4 concentration with SDB severity. ResultsA total of 104 children with SDB and mean obstructive apnea-hypopnea index-AHI of 4.8 ± 5.3 episodes/h (primary snoring: n = 19; mild SDB: n = 49; moderate/severe SDB: n = 36) and 13 controls (no snoring; AHI: 0.4 ± 0.2 episodes/h) were recruited. The four study subgroups were similar regarding LTB4 serum concentration (P = 0.64). High LTB4 (>170.3 pg/mL) was a significant predictor of tonsillar hypertrophy after adjustment for age and gender (OR 3.0 [1.2–7.2]; P = 0.01). There was no association between AHI or desaturation index and LTB4 serum concentration (r = −0.08; P = 0.37 and r = −0.1; P = 0.30, respectively). ConclusionNo association was identified between SDB severity and LTB4 levels, but high LTB4 concentration predicted tonsillar hypertrophy.

Suppressive Effect of the n-Hexane Extract of Litsea japonica Fruit Flesh on Monosodium-Iodoacetate-Induced Osteoarthritis in Rats.

We examined the antiosteoarthritic effect of the n-hexane extract of Litsea japonica fruit flesh (LJF-HE) in a rat model of monosodium-iodoacetate- (MIA-) induced osteoarthritis. LJF-HE significantly reduced the difference in weight-bearing capabilities of the hind paws between healthy and MIA-treated rats. Histological examination of the knee joints indicated that LJF-HE suppressed cartilage and bone destruction. Additionally, there were decreases in the expression of matrix metalloproteinase-2 and metalloproteinase-9 and cyclooxygenase-2 in the joints. The serum levels of deoxypyridinoline (DPD) and osteocalcin, which are markers of bone metabolism, also decreased. Furthermore, LJF-HE significantly suppressed infiltration of inflammatory cells into the synovium and inhibited the expression of proinflammatory cytokines such as tumor necrosis factor- (TNF-) α, interleukin- (IL-) 1, and IL-6 in the joints and serum. The serum levels of leukotriene B4 and lipoxygenase were also significantly lowered by LJF-HE. Finally, LJF-HE inhibited the production of nitric oxide, prostaglandin E2, IL-6, and TNF-α in lipopolysaccharide-activated macrophages, which might be associated with inhibited phosphorylation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase. Our data suggest that LJF-HE has an anti-inflammatory effect and may have potential as an antiosteoarthritic agent.

A randomized double-blind placebo-controlled study adding high dose vitamin D to analgesic regimens in patients with musculoskeletal pain.

The current mode of therapy for many patients with musculoskeletal pain is unsatisfactory. We aimed to assess the impact of adding 4000 IU of vitamin D on pain and serological parameters in patients with musculoskeletal pain. This was a randomized, double-blinded and placebo-controlled study assessing the effect of 4000 IU of orally given vitamin D3 (cholecalciferol) (four gel capsules of 1000 IU, (SupHerb, Israel) vs. placebo on different parameters of pain. Eighty patients were enrolled and therapy was given for 3 months. Parameters were scored at three time points: prior to intervention, at week 6 and week 12. Visual analogue scale (VAS) scores of pain perception were recorded following 6 and 12 weeks. We also measured serum levels of leukotriene B4 (LTB4), interleukin 6 (IL-6), tumor necrosis factor alpha (TNFα) and prostaglandin E2 (PGE2) by ELISA. The group receiving vitamin D achieved a statistically significant larger decline of their VAS measurement throughout the study compared with the placebo group. The need for analgesic 'rescue therapy' was significantly lower among the vitamin D-treated group. TNFα levels decreased by 54.3% in the group treated with vitamin D and increased by 16.1% in the placebo group. PGE2 decreased by39.2% in the group treated with vitamin D and increased by 16% in the placebo group. LTB4 levels decreased in both groups by 24% (p < 0.05). Adding 4000 IU of vitamin D for patients with musculoskeletal pain may lead to a faster decline of consecutive VAS scores and to a decrease in the levels of inflammatory and pain-related cytokines.

Clinical study of serum immunoglobulin E, immunoglobulin G4 and leukotriene B4 levels in children with acute asthma

Objective To evaluate the clinical significance of serum immunoglobulin (Ig)E, IgG4 and leukotriene B4 changes in children with acute asthma. Methods Totally 316 children aged 6 months to 15 years were enrolled and evaluated for the study.Asthma group consisted of 107 patients with acute bronchospasm and histories of recurrent asthma; bronchopneumonia group consisted of 109 patients with bronchopneumonia; and 100 healthy children were assigned as controls.Each group was further divided into 3 subgroups: infants, preschool children and children aged ≥ 7 years.Serum IgE, IgG4 and leukotriene B4 concentrations were determined.The test between 2 groups comparing was performed and compared by the statistical analysis. Results A significant increase in serum IgE levels were observed at all ages in asthma group compared with bronchopneumonia group and control group, respectively, serum IgE levels were also significantly higher in bronchopneumonia group compared with control group (F=60.69, 559.22, P infants > preschool children(F=87.14, P<0.001). Serum IgG4 and leukotriene B4 levels were significantly increased in asthma group and bronchopneumonia group compared with control group, and also in bronchopneumonia group compared with the asthma group (F=97.45, 100.74, P<0.001). However, no significant changes were found among different ages in asthma group. Conclusions The study suggests that infants and schoolchildren with asthma have higher allergic sensitivity.Serum IgG4 should be considered as a protective other than allergic antibody, and enhanced serum leukotriene B4 levels observed in children with acute asthma might be induced by infectious responses. Key words: Asthma; Child; Serum; Immunoglobulin E; Immunoglobulin G4; Leukotriene B4

AB0873 A Randomized Double-Blind Placebo-Controlled Study Adding High Dose Vitamin D to Analgesic Regimens in Patients with Musculoskeletal Pain

BackgroundThe current mode of therapy for many patients with musculoskeletal is unsatisfactory.ObjectivesTo assess the impact of adding 4,000 IU of vitamin D on pain and serological parameters in patients with...

Increased inflammatory mediator in exhaled breath condensate from asthmatic children

Purpose: There has recently been increasing interest in the use of exhaled breath condensate (EBC) as a simple noninvasive means for understanding the physiology of asthma. The aim of this study was to evaluate the levels of leukotriene B4 (LTB4) and eosinophil cationic protein (ECP) in the EBC of asthmatic children. Methods: We measured LTB4 and ECP levels in EBC from children aged 6–14 years, including healthy children (n = 25) and asthmatic children (n = 25). We also measured serum LTB4 and serum ECP. Pulmonary function tests and methacholine challenge tests were performed on all subjects. Results: Exhaled LTB4 levels were increased significantly in patients with asthma compared to normal subjects (7.1 ± 3.7 pg/mL vs. 2.2 ± 1.7 pg/mL, P < 0.05). Serum LTB4 levels were not significantly different in patients with asthma compared to normal subjects (674.7 ± 484.1 pg/mL vs. 487.1 ± 272.0 pg/mL, P = 0.156,) and no significant correlations were found between exhaled and serum LTB 4 concentrations in children with asthma (r = 0.052, P = 0.758). Exhaled ECP levels were not significantly different in patients with asthma compared to normal subjects (P = 0.419). Serum ECP levels were significantly increased in patients with asthma compared to normal subjects (44.37 ± 32.14 μg/L vs. 16.40 ± 13.23 μg/L, P = 0.001). Conclusion: We found significantly elevated LTB 4 levels in the EBC of asthmatic children. Our results suggest that EBC may be one of the supportive tools to measure airway inflammation in children with asthma. (Allergy Asthma Respir Dis 2014;2:332-336)

Clinical Significance of Leukotriene B4 and Extracellular Matrix Metalloproteinase Inducer in Acute Coronary Syndrome

Leukotriene B4 (LTB4) and extracellular matrix metalloproteinase (EMMPRIN) have been suggested as modulators of atherosclerotic plaque instability. This study sought to evaluate the potential diagnostic implication of LTB4 and EMMPRIN in patients with acute coronary syndrome (ACS). Patients (n=153) who underwent coronary angiography, including 105 patients diagnosed with ACS, were divided into four groups: stable angina pectoris (SAP, n=19), unstable angina pectoris (UAP, n=39), acute myocardial infarction (AMI, n=66) and control (with normal coronary angiography, n=29). EMMPRIN expression in peripheral blood mononuclear cells was determined by flow cytometry and serum LTB4 levels were measured by ELISA. To examine whether LTB4 can regulate the expression of EMMPRIN and matrix metalloproteinases (MMPs) in macrophages, differentiated THP-1 macrophages were stimulated with different concentrations of LTB4 (10-10-10-7mmol/L). Expression of EMMPRIN was evaluated by Western blotting. MMP-9 mRNA expression and enzymatic activity were determined by RT-PCR and SDS-PAGE gelatin zymography. Serum LTB4 concentration was significantly higher in AMI and UAP groups, compared with control and SAP groups (p < 0.01). Subgroups analysis showed that LTB4 was significantly higher in the AMI < 24h group, compared with the AMI > 24h group. Expression of EMMPRIN on circulating monocytes was significantly higher in patients with UAP and AMI (> 24h), compared with control, SAP and AMI (< 24h) groups (p < 0.05). In vitro study showed LTB4 up-regulated the expression of EMMPRIN, as well as the expression and activity of MMP-9, in cultured THP-1-derived macrophages (p < 0.05). LTB4 and EMMPRIN are associated with the pathogenesis of ACS and may be potential biomarkers for patients with ACS.

Atorvastatin Inhibits the 5-Lipoxygenase Pathway and Expression of CCL3 to Alleviate Atherosclerotic Lesions in Atherosclerotic ApoE Knockout Mice

The 5-lipoxygenase (5-LO) pathway and the chemokine CCL3 are involved in the inflammatory processes of atherosclerosis. Statins have shown cholesterol-independent pleiotropic effects on antiimmune and antiinflammatory responses in atherosclerosis. We postulated that this effect may be associated with the 5-LO pathway and CCL3. ApoE knockout mice were randomized into control group (normal diet), atherosclerosis group (high-cholesterol diet), and atorvastatin group (high-cholesterol diet and atorvastatin). Sixteen weeks later, aortic roots were stained with hematoxylin and eosin. Total cholesterol and low-density lipoprotein cholesterol were measured by the enzymatic methods. The gene and protein expressions of 5-LO and CCL3 were detected separately through real-time reverse transcription polymerase chain reaction and western blotting analyses. The serum levels of leukotriene B4 and leukotriene D4 were measured by enzyme-linked immunosorbent assay. All mice have atherosclerotic plaques, mice in the control group have only tiny atherosclerotic plaques, but mice in the atherosclerosis group and atorvastatin group have typical atherosclerotic plaques. The corrected plaque areas (plaque area/luminal area) of the aortas of mice in the atorvastatin group were significantly decreased compared with those of the atherosclerosis group. The serum cholesterol levels of the atorvastatin group were not of significant difference compared with those of the atherosclerosis group. The gene and protein expressions of 5-LO and CCL3 in the aortas, as well as the serum levels of leukotriene B4 and leukotriene D4 in atorvastatin group, were markedly reduced compared with those of the atherosclerosis group. These data suggested that atorvastatin significantly alleviated atherosclerotic lesions by inhibiting the 5-LO pathway and down regulating the expression of CCL3 in ApoE-/- mice.

Deleterious Effects of High Concentrations of (-)-Epigallocatechin-3-Gallate and Atorvastatin in Mice With Colon Inflammation

Epigallocatechin-3-gallate (EGCG), atorvastatin (ATST), and their combination have been previously shown to inhibit colon carcinogenesis in animal models. We further investigated their inhibitory activities in azoxymethane (AOM) and dextran sulfate sodium (DSS)-treated Balb/cJ mice and CD-1 mice in 2 slightly different models. The mice were maintained on the AIN93M diet, or a similar diet containing 0.03%, 0.1%, or 0.3% EGCG; 60-ppm ATST; or a combination of 0.1% EGCG and 60-ppm ATST. Unexpectedly, no significant inhibitory activity was observed, and some of the treatment groups resulted in higher tumor multiplicity. To study the effects of EGCG on colon inflammation, CD-1 or C57BL/6 mice were treated with 1.5% DSS for 7 days and sacrificed 3 days later. DSS induced rectal bleeding and colon shortening; treatment with 0.5% EGCG exacerbated the bleeding and decreased mouse body weight. Dietary 0.5% EGCG also increased serum levels of leukotriene B4 and prostaglandin E2. These results suggest that, in mice bearing colon inflammation, high concentrations of EGCG and ATST enhance colon bleeding and may promote colon carcinogenesis.

Evidence for eosinophil recruitment, leukotriene B4 production and mast cell hyperplasia following Toxocara canis infection in rats

It is well known that eosinophilia is a key pathogenetic component of toxocariasis. The objective of the present study was to determine if there is an association between peritoneal and blood eosinophil influx, mast cell hyperplasia and leukotriene B(4) (LTB(4)) production after Toxocara canis infection. Oral inoculation of 56-day-old Wistar rats (N = 5-7 per group) with 1000 embryonated eggs containing third-stage (L3) T. canis larvae led to a robust accumulation of total leukocytes in blood beginning on day 3 and peaking on day 18, mainly characterized by eosinophils and accompanied by higher serum LTB(4) levels. At that time, we also noted increased eosinophil numbers in the peritoneal cavity. In addition, we observed increased peritoneal mast cell number in the peritoneal cavity, which correlated with the time course of eosinophilia during toxocariasis. We also demonstrated that mast cell hyperplasia in the intestines and lungs began soon after the T. canis larvae migrated to these compartments, reaching maximal levels on day 24, which correlated with the complete elimination of the parasite. Therefore, mast cells appear to be involved in peritoneal and blood eosinophil infiltration through an LTB(4)-dependent mechanism following T. canis infection in rats. Our data also demonstrate a tight association between larval migratory stages and intestinal and pulmonary mast cell hyperplasia in the toxocariasis model.

Evidence for eosinophil recruitment, leukotriene B4 production and mast cell hyperplasia following Toxocara canis infection in rats

It is well known that eosinophilia is a key pathogenetic component of toxocariasis. The objective of the present study was to determine if there is an association between peritoneal and blood eosinophil influx, mast cell hyperplasia and leukotriene B4 (LTB4) production after Toxocara canis infection. Oral inoculation of 56-day-old Wistar rats (N = 5-7 per group) with 1000 embryonated eggs containing third-stage (L3) T. canis larvae led to a robust accumulation of total leukocytes in blood beginning on day 3 and peaking on day 18, mainly characterized by eosinophils and accompanied by higher serum LTB4 levels. At that time, we also noted increased eosinophil numbers in the peritoneal cavity. In addition, we observed increased peritoneal mast cell number in the peritoneal cavity, which correlated with the time course of eosinophilia during toxocariasis. We also demonstrated that mast cell hyperplasia in the intestines and lungs began soon after the T. canis larvae migrated to these compartments, reaching maximal levels on day 24, which correlated with the complete elimination of the parasite. Therefore, mast cells appear to be involved in peritoneal and blood eosinophil infiltration through an LTB4-dependent mechanism following T. canis infection in rats. Our data also demonstrate a tight association between larval migratory stages and intestinal and pulmonary mast cell hyperplasia in the toxocariasis model.

Anti-atherogenic effect of BHB-TZD having inhibitory activities on cyclooxygenase and 5-lipoxygenase in hyperlipidemic mice

Cyclooxygenase (COX) and 5-lipoxygenase (5-LOX), which play pivotal roles in atherogenesis, have been reported to be involved in plaque stability. Licofelone, a dual COX and 5-LOX inhibitor, has been reported to possess anti-atherogenic effect in rabbit atherosclerosis model. We therefore investigated the anti-atherogenic effect of BHB-TZD [5-(3,5-di-tert-butyl-4-hydroxybenzylidene)thiazolidin-2,4-dione], a dual COX and 5-LOX inhibitor, in low density lipoprotein receptor null (LDLR−/−) mice. Fifteen LDLR−/− mice were fed a western diet (control group), whereas 15 were fed a western diet plus 0.1% (w/w) BHB-TZD (BHB-TZD group). After 8 weeks, the BHB-TZD group had markedly lower serum levels of leukotriene B4 and prostaglandin E2 than the control group. Interestingly, BHB-TZD treatment also reduced plasma triglyceride level without significant changes in total cholesterol and HDL levels. Compared with control mice, BHB-TZD fed mice had 52% fewer fatty streak lesions in the aortic sinus, as well as fewer initial lesions in the aortic arch. Macrophage infiltration into the lesions was 40% lower, and collagen and smooth muscle cells were increased by 102% and 96%, respectively, in the BHB-TZD group compared with the control group. In addition, aortic expression of proatherogenic molecules including TNF-α, IL-1β, IL-6, MCP-1 and VCAM-1, was lower in the BHB-TZD group than the control group. BHB-TZD treatment also reduced MMP-2 and MMP-9 expressions in aorta. In conclusion, BHB-TZD effectively attenuated atherosclerosis in mouse model, suggesting its therapeutic potential for atherosclerosis.

Reduction in primary nonfunction of syngeneic islet transplants with nordihydroguaiaretic acid, a lipoxygenase inhibitor.

To study the effectiveness of a lipoxygenase inhibitor, nordihydroguaiaretic acid (NDGA), in the reduction of primary nonfunction, an insufficient number of syngeneic islets were transplanted underneath the renal capsule with NDGA administered daily for 4 weeks. After transplantation of the 150 islets, the decrement of blood glucose levels was significantly faster in the mice that had received NDGA than in the mice that had received no drug at all or dimethyl sulfoxide (DMSO) (p < 0.005, p < 0.05). The mean duration of temporary posttransplant hyperglycemia was 22.3 +/- 3.2 (n = 10), 35.9 +/- 2.3 (n = 14), and 33.7 +/- 4.1 (n = 6) days for the respective groups. The diabetic mice that received 300 islets had their blood glucose levels decrease faster than those that received 150 islets (19.7 +/- 1.6 vs. 35.9 +/- 2.3 days, n = 14. p < 0.0001). There was no significant difference in the blood glucose reducing effect between the mice that received 150 islets with NDGA and the mice that received 300 islets [22.3 +/- 3.2 (n = 10) vs. 19.7 +/- 1.6 (n = 14) days, p > 0.05]. The insulin content of the graft from the mice treated with 150 islets and NDGA (3.02 +/- 0.24 microg, n = 4) was higher than that from the mice that received 150 islets but no treatment (1.10 +/- 0.26 microg, n = 15, p < 0.005) or that had been treated with DMSO (1.21 +/- 0.30 microg, n = 4, p <0.05). The insulin content of the pancreas remnant had no significant differences among the three groups. The net glucose-stimulated insulin secretion was 0.82 +/- 0.14 vs. 0.20 +/- 0.10 microIU/islet x 60 min (n = 8, p < 0.005) and 0.59 +/- 0.08 vs. 0.04 +/- 0.02 microIU/islet x 60 min (n = 8, p < 0.0001) for islets cultured without NDGA vs. with NDGA at 1 and 2 weeks, respectively. However, the insulin content of the cultured islets was similar between the two groups for up to 2 weeks of incubation (at 1 week: 0.71 +/- 0.01 vs. 0.67 +/- 0.04 ng/islet, n = 8, p > 0.05; at 2 weeks: 0.71 +/- 0.02 vs. 0.80 +/- 0.07 ng/islet, n = 8, p > 0.05). Serum leukotriene B4 (LTB4) concentrations before and between the fifth and seventh days after transplantation were determined. For diabetic mice that received 150 islets, serum LTB4 levels were 25,835 +/- 3,335 and 27,631 +/- 3,136 pg/ml (n = 4, p > 0.05). For diabetic mice that received 150 islets and NDGA, the corresponding figures were 22,401 +/- 2,706 pg/ml and 27,530 +/- 2,190 pg/ml (n = 8, p > 0.05). The graft histology revealed viable islet cells and networks of close vascular structures around the islets and did not reveal microscopic differences among the samples of all four groups. In conclusion, our data revealed that daily administration of NDGA for 4 weeks enhanced isoislet engraftment and preserved three times more mass of the islet beta cells in the isografts. This result indicates that NDGA reduces primary nonfunction of islet syngeneic grafts in diabetic mice.