Insulin resistance predicts sustained virological response to treatment of chronic hepatitis C independently of the IL28b rs12979860 polymorphism

BACKGROUND

Insulin resistance has been strongly associated with the attainment of sustained viral response (SVR) in hepatitis C patients.

AIM

To determine, in a cohort of Spanish patients with chronic hepatitis C treated with peginterferon plus ribavirin (P+R), whether insulin resistance predicts SVR independently of interleukin-28B rs12979860 polymorphism.

METHODS

Insulin resistance was measured as [HOMA-IR = Insulin (IU/mL)*glucose (mmol/L)/22.5]. Genotype, viral load and histological fibrosis using Scheuer score were also measured. Binary logistic regression analysis was used for statistical purposes.

RESULTS

In a cohort of 240 patients [78% genotype 1, 24% showing advanced fibrosis, 71% high viral load (≥800 000 IU/mL), 31% IL28b genotype CC and 50% with HOMA >2] treated with P+R, 126 (53%) reached SVR. HOMA-IR index (HOMA <2: 63% vs. HOMA >2: 42%; P = 0.001 and IL28b (genotype CC: 68% vs. genotype CT/TT: 45%; P = 0.002) were significantly associated with SVR. In multivariable logistic regression analysis in the overall cohort, variables independently associated were: viral genotype OR: 0.29 (95% CI: 0.11-0.78), P = 0.01; fibrosis OR: 1.62 (95% CI: 1.22-2.16), P = 0.001; HOMA-IR OR: 1.22 (95% CI: 1.02-1.47), P = 0.03; and IL28B genotype OR: 2.43 (95% CI: 1.45-4.07), P = 0.001. The analyses also showed that degree of steatosis, HOMA-IR >2, mild fibrosis and IL28B CC genotype were significantly related to SVR in patients infected with HCV genotypes 1&4, but not in those with genotypes 2&3. No differences were seen in glucose, insulin level or HOMA-IR index segregated according to IL28B genotypes.

CONCLUSION

Our results suggest that insulin resistance, fibrosis stage and IL28B polymorphisms were independent variables associated with sustained viral response.

Fusarium spp. Causing Dry Rot of Seed Potato Tubers in Michigan and Their Sensitivity to Fungicides

A survey of seed potato tubers in Michigan seed production storage facilities was carried out during 2009 and 2010. Fusarium spp. associated with tuber dry rot symptoms were identified to species and tested for sensitivity to difenoconazole, fludioxonil, and thiabendazole. Symptomatic tubers (n = 370) were collected from a total of 51 seed lots, from which 228 isolates of Fusarium were recovered and identified to 11 species. Fusarium oxysporum was the most commonly isolated species (30.3%), followed by F. equiseti (19.3%). F. sambucinum and F. avenaceum were third most prevalent (each at 13.6%). Less prevalent species (each at 4 to 10%) included F. cerealis, F. solani, and F. acuminatum; and species present at ≤3% included F. sporotrichioides, F. torulosum, F. tricinctum, and F. graminearum. Representative isolates of all species were pathogenic when inoculated onto seed tubers ('Dark Red Norland'). Isolates of F. sambucinum were the most virulent. All 228 isolates of Fusarium were sensitive to difenoconazole (effective fungicide concentration that caused 50% inhibition of mycelial growth [EC₅₀] < 5 mg/liter). Insensitivity to fludioxonil (EC₅₀ > 100 mg/liter) was detected only for F. sambucinum and F. oxysporum isolates at 8.9 and 20.4%, respectively. All isolates were sensitive to thiabendazole (EC₅₀ < 5 mg/liter), except for those of F. sambucinum (EC₅₀ > 100 mg/liter). Therefore, knowledge of what Fusarium spp. are present in seed potato storage facilities in Michigan may be important if using fludioxonil or thiabendazole for seed piece treatment but not when using difenoconazole.

Statins and portal hypertension: a new pharmacological challenge

Portal hypertension is a hemodynamic abnormality that involves a high risk of disability as well as a reduced life expectancy in patients with cirrhosis. Progress in the knowledge of pathophysiology of portal hypertension has opened a new perspective for different pharmacological approaches. In this context, the pleiotropic actions of statins on endothelial cell function have emerged as new options to reduce portal pressure levels by targeting multiple molecular pathways involved in hepatic vascular homeostasis. We highlight how statins may target some molecular pathways involved in the pathophysiology of portal hypertension and how these drugs may correct impaired hepatic vascular tone.

iNOS activation regulates β-catenin association with its partners in endothelial cells

BACKGROUND

Signals that disrupt β-catenin association to cadherins may influence the translocation of β-catenin to the nucleus to regulate transcription. Post-translational modification of proteins is a signalling event that may lead to changes in structural conformation, association or function of the target proteins. NO and its derivatives induce nitration of proteins during inflammation. It has been described that animals treated with NO donors showed increased permeability due to modulation of VE-cadherin/catenin complex. We, therefore, aim to evaluate the effect of iNOS activation on the expression, nuclear localisation and function of β-catenin in endothelial cells.

METHODOLOGY/PRINCIPAL FINDINGS

Expression, nuclear localisation, post-translational modifications and function of β-catenin was analysed by cell fractionation, immunoprecipitation, immunoblots, QRT-PCR and permeability assays in murine endothelial cells (H5V). Influence of macrophage activation on expression of VE-cadherin/p120-catenin/β-catenin complex in co-cultured H5V cells was also assessed. Activation of macrophages to produce NO provoked a decrease in VE-cadherin/p120-catenin/β-catenin expression in H5V cells. Phosphorylation of β-catenin, p120-catenin and VE-cadherin, and reduction in the barrier properties of the cell monolayer was associated with iNOS induction. Moreover, high NO levels provoked nitration of β-catenin, and induced its translocation to the nucleus. In the nucleus of NOS activated cells, nitration levels of β-catenin influenced its association with TCF4 and p65 proteins. High levels of NO altered β-catenin mediated gene expression of NFκB and Wnt target genes without affecting cell viability.

CONCLUSIONS

NOS activity modulates β-catenin post-translational modifications, function and its association with different partners to promote endothelial cell survival. Therapeutic manipulation of iNOS levels may remove a critical cytoprotective mechanism of importance in tumour angiogenesis.

Evidence of involvement of the receptor for advanced glycation end-products (RAGE) in the adhesion of Helicobacter pylori to gastric epithelial cells

The adherence of Helicobacter pylori to gastric epithelial cells is required for prolonged persistence in the stomach and for induction of injury. Here, we first reported a new role of the receptor for advanced glycation end-products (RAGE) on the adherence of H. pylori to gastric epithelial cells, assessed by different methods and binding to immobilized RAGE. RAGE-targeted knock-down in MKN74 cell line markedly reduced not only the adhesion of H. pylori, but also the levels of IL-8 transcripts and protein released in response to infection. These data suggest that RAGE may represent a new factor on the pathogenesis of H. pylori infection.

First Report of Fusarium torulosum Causing Dry Rot of Seed Potato Tubers in the United States

Fusarium dry rot of potato (Solanum tuberosum L.) is a postharvest disease caused by several Fusarium species and is of worldwide importance. Thirteen species of Fusarium have been implicated in fungal dry rots of potatoes worldwide. Among them, eight species have been reported in the northern United States (2). In Michigan potato production, F. sambucinum was the predominant species reported to be affecting seed potato in storage and causing seed piece decay after planting (3). Some previous identifications of F. sambucinum as dry rot may have been F. torulosum since F. torulosum was previously classified within F. sambucinum (4). To further investigate this, dry rot symptomatic tubers were collected from Michigan seed lots in the summers of 2009 and 2010. Small sections from the margins of necrotic regions were cut with a scalpel, surface sterilized in 0.5% sodium hypochlorite for 10 s, rinsed twice in sterile distilled water, and blotted with sterile filter paper. The tissue pieces were plated on half-strength potato dextrose agar (PDA) amended with 0.5 g/liter of streptomycin sulfate and incubated at 23°C for 5 to 7 days. Cultures resembling Fusarium species were transferred onto water agar, and single hyphal tips from actively growing isolates were removed and plated either on carnation leaf agar (CLA) or on half-strength PDA to generate pure cultures. Among the Fusarium isolates obtained, five isolates were identified as F. torulosum (GenBank Accessions Nos. JF803658-JF803660). Identification was based on colony and conidial morphology on PDA and CLA, respectively. These features included slow growth (2.8 ± 0.2 cm in 5 days), white mycelium that became pigmented with age, narrow concentric rings, red or white pigmentation on agar, macroconidia (32.4 ± 0.4 μm average length) with five septa, a pointed apical cell, and a foot-shaped basal cell (4). The identity was confirmed through DNA extraction followed by amplification and sequencing of the translation elongation factor (EF-1α) gene region (1). The Fusarium-ID.v (1) and the NCBI database were used to obtain the closest match (99%) to previously sequenced materials (GenBank Accession No. AJ543611). Pathogenicity testing was done on disease-free potato tubers cv. Red Norland. Tubers were surface sterilized for 10 min in 0.5% sodium hypochlorite and rinsed twice in distilled water. Three tubers per isolate were injected with 20 μl of a conidial suspension (10⁶ conidia/ml) made from F. torulosum cultures grown on PDA for 7 to 10 days. Control tubers were injected with 20 μl of sterile distilled water. All tubers inoculated with F. torulosum developed typical potato dry rot symptoms consisting of a brown and dry decay. There was no disease incidence on the control tubers. F. torulosum was reisolated from the symptomatic tubers. To our knowledge, this is the first report of F. torulosum causing potato dry rot in the United States. References: (1) D. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004. (2) L. E. Hanson et al. Phytopathology 86:378, 1996. (3) M. L. Lacy and R. Hammerschmidt. Fusarium dry rot. Extension Bulletin. Retrieved from http://web1.msue.msu.edu/msue/iac/onlinepubs/pubs/E/E2448POT , 23 May 2010. (4) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Wiley-Blackwell, Hoboken, NJ, 2006.

High prevalence of virulence-associated genotypes in Helicobacter pylori clinical isolates in the Region del Maule, Chile

The prevalence of Helicobacter pylori infection and the gastric cancer mortality rate in Chile are remarkably high. This study identified some virulence-associated genes in 78 H. pylori clinical isolates from dyspeptic patients from the Region del Maule, which is the region with the higher gastric cancer mortality rate in the country. The cagA, vacA and babA2 genes were detected in 94.9%, 100% and 97.4%, respectively. Two or more EPIYA C motifs were presented in 48.6% of cagA-positive strains, and this was associated with more severe histopathological findings in the gastric mucosa.

Diabetes and cancer: Looking at the multiligand/RAGE axis

The association between diabetes and hyperglycemia and the associated increased risk of several solid and hematologic malignancies has been the subject of investigation for many years. Although the association is not fully understood, current knowledge clearly indicates that diabetes may influence malignant cell transformation by several mechanisms, including hyperinsulinemia, hyperglycemia and chronic inflammation. In this context, the receptor for advanced glycation end-products (RAGE) has emerged as a focal point in its contribution to malignant transformation and tumor growth. We highlight how RAGE, once activated, as it manifests itself in conditions such as diabetes or hyperglycemia, is able to continuously bring about an inflammatory milieu, thus supporting the contribution of chronic inflammation to the development of malignancies.

Viral agents causing lower respiratory tract infections in hospitalized children: evaluation of the Speed-Oligo® RSV assay for the detection of respiratory syncytial virus

Respiratory syncytial virus (RSV) is the viral agent which is more frequently involved in lower respiratory tract infections (LRTIs) in infants under 1 year of age in developed countries. A new oligochromatographic assay, Speed-Oligo® RSV, was designed and optimized for the specific detection and identification of RSV subtypes A and B. The test was evaluated in 289 clinical samples from 169 hospitalized children using an immunochromatography (IC) test, virus isolation by culture, and an in-house real-time polymerase chain reaction (RT-PCR). Other viruses causing LRTIs were investigated by cell culture or PCR-based tests. Sixty-two patients were infected by RSV (36.7%). In addition, adenovirus, influenza B, parainfluenza 2, and human metapneumovirus were detected in rates ranging from 5 to 8%. A proportion of 10.1% of the patients had mixed infections. The sensitivity, specificity, and positive and negative predictive values were, respectively, 94.9, 99.4, 98.9, and 97.4% for Speed-Oligo® RSV, 92.9, 96.3, 92.9, and 96.3% for RT-PCR/RSV, and 58.4, 98.1, 93.3, and 82.6% for IC. Our rates of viral detection and co-infection were similar to those of previously reported series. Finally, we find that Speed-Oligo® RSV is a rapid and easy-to-perform technique for the detection of RSV and the identification of subtypes A and B.

First Report of Pythium sterilum Causing Root Rot of Blueberry in the United States

In September 2009, ~40 declining blueberry plants (Vaccinium corymbosum L. 'Jersey') were observed in a poorly drained area of a 30-year-old field near Fennville, MI. The stunted bushes had yellow leaves and defoliation; others were completely dead. The grower reported that the bushes had been declining over several years. Root samples tested positive in a Phytophthora ELISA test (Agdia Inc., Elkhart IN). Twenty root pieces (2 cm long and 2 to 3 mm in diameter) were surface disinfested and plated on Rye A agar; five yielded fungal-like colonies that were subcultured on potato dextrose agar (PDA). One isolate was white and grew slowly (3 to 4 mm/day at 22 to 24°C). Three isolates were white and grew faster (10 to 12 mm/day at 22 to 24°C) in a chrysanthemal pattern. The fifth was a Fusarium sp. DNA of the white colonies was extracted and the internal transcribed spacer (ITS) region was sequenced using ITS1 (5'-TCCGTAGGTGAACCTGCGG-3') and ITS4 (5'-TCCTCCGCTTATTGATATGC-3') primers. The slow-growing morphotype had 99% identity to Phytophthora sp. isolate 92-209C (Accession No. EU106591) in GenBank but failed to induce symptoms in multiple inoculation tests. The fast-growing morphotype (Accession No. HQ398249) had 98% identity to Pythium sterilum UASWS0265 from declining alder stands in Poland (Accession No. DQ525089). Sequencing of the COXII gene using the FM66/FM58 primer set (3) yielded a product (Accession No. HQ721468) with 100% identity to P. sterilum GD32a from forest soil in Poland (Accession No. EF421185). Hyphae were hyaline, coenocytic, and 4 to 7 μm wide with some swellings at the tips (7 to 9 μm wide). No sporangia, oogonia, or antheridia were observed. Mycelium tested positive in the ELISA test described above. According to Agdia Inc., 10 of 19 tested Pythium spp. have shown similar cross reactivity. Pythium spp. are known to cause root rot of blueberries in Oregon (2). In British Columbia, P. sterilum was commonly isolated from roots of declining blueberry bushes (4). P. sterilum Belbahri & Lefort only reproduces asexually (1). Our isolate was similar but did not produce sporangia in water or on PDA, V8 juice agar, Rye A agar, or water agar. Roots of 10 2-month-old 'Bluecrop' cuttings were placed in an aqueous suspension of rinsed mycelium (0.1 g/ml) from 21-day-old cultures grown in V8 broth or in sterile deionized water (control). After 1 h, plants were potted in peat moss/perlite (2:1) or autoclaved sand (five each) and placed in a glasshouse at 25°C. After 7 days, inoculated plants in both soil types had wilted or collapsed with significant necrosis on the roots and primary shoot. Control plants showed no symptoms. In a similar experiment with 6-month-old plants in sand, symptoms appeared after 10 to 12 days. The pathogen was recovered from surface-disinfested root and stem sections of all inoculated plants but not control plants and its identity was confirmed by sequencing of the ITS region. To our knowledge, this is the first report of P. sterilum on blueberries in the United States. While this disease appears to be uncommon in Michigan, it is a potential cause of plant decline, the diagnosis of which may be complicated by cross reactivity in ELISA testing. References: (1) L. Belbahri et al. FEMS Microbiol. Lett. 255:209, 2006. (2) D. R. Bryla and R. G. Linderman. HortScience 43:260, 2008. (3) F. N. Martin. Mycologia 92:711, 2000. (4) S. Sabaratnam. BC Plant Health Fund Final Report. B.C. Retrieved from http://www.agf.gov.bc.ca/cropprot/phf_final_report.pdf , 2008.

First Report of in vitro Fludioxonil-Resistant Isolates of Fusarium spp. Causing Potato Dry Rot in Michigan

Fusarium dry rot of potato (Solanum tuberosum) is a postharvest disease caused by several Fusarium spp. Dry rot is managed primarily by reducing tuber bruising and promoting rapid wound healing. Dry rot symptomatic tubers were collected from Michigan seed lots in 2009 and 2010. The isolates may not have been exposed to fludioxonil because currently applications are restricted to seed not intended for seed production (3). Small sections were cut from the margins of necrotic regions with a scalpel, surface sterile in 10% sodium hypochlorite for 10 s, rinsed twice in sterile distilled water, and blotted with sterile filter paper. The tissue pieces were plated on half-strength potato dextrose agar (PDA) amended with 0.5 g/liter of streptomycin sulfate. The dishes were incubated at 23°C for 5 to 7 days. Cultures resembling Fusarium spp. were transferred onto water agar and hyphal tips from the margin of actively growing isolates were removed with a sterile probe and plated either on carnation leaf agar (CLA) or on half-strength PDA to generate pure cultures. Fusarium isolates were obtained and used for further studies. Among them, 54 were identified as Fusarium oxysporum and 23 as F. sambucinum. Identification was based on colony and conidial morphology on PDA and CLA, respectively. The identity was confirmed through DNA extraction followed by amplification and sequencing of the translation elongation factor (EF-1α) gene region. The Fusarium-ID v. (2) and the NCBI database were used to obtain the closest match to previously sequenced materials. Pathogenicity testing was done on disease-free potato tubers, cv. FL 1879. Tubers were surface sterilized for 10 min in 10% sodium hypochlorite and rinsed twice in distilled water. Three tubers per isolate were injected with 20 μl of a conidial suspension (10⁶ conidia/ml) made from cultures grown on PDA for 7 days. Control tubers were injected with 20 μl of sterile distilled water. All tubers inoculated with F. sambucinum and F. oxysporum developed typical potato dry rot symptoms consisting of dry brown decay lesions. F. sambucinum and F. oxysporum were reisolated from all symptomatic tubers. An effective concentration for 50% reduction in growth (EC₅₀) was determined for each F. sambucinum and F. oxysporum isolate for thiabendazole (TBZ), fludioxonil, and difenoconazole using the spiral gradient endpoint method (1). Sensitive and resistant F. sambucinum and F. oxysporum isolates were reported. Fifteen isolates of F. sambucinum and thirty-four of F. oxysporum were resistant to fludioxonil with EC₅₀ greater than 130 mg/liter. The remainder was sensitive to fludioxonil with EC₅₀ ranging from 0.8 to 4.9 mg/liter. To our knowledge, this is the first report of resistance to fludioxonil in isolates of F. sambucinum and F. oxysporum in Michigan. Fusarium insensitivity in laboratory studies may not translate directly to commercial production. This disparity may result from interactions not experienced in mixed populations or within a living host. There has been no compelling evidence to suggest that fludioxonil has failed to perform because of insensitivity to Fusarium. The occurrence of such isolated strains necessitates the development and registration of partner chemistries that can preempt any future concerns on lack of performance of products in use. References: (1) H. Förster et al. Phytopathology 94:163, 2004. (2) D. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004. (3) R. D. Peters et al. Plant Dis. 92:172, 2008.

E-cadherin contributes to the bystander effect of TK/GCV suicide therapy and enhances its antitumoral activity in pancreatic cancer models

The thymidine kinase/ganciclovir (TK/GCV) cancer gene therapy approach is based on inducing GCV metabolite cytotoxicity in tumor cells expressing the herpes simplex virus TK gene and exposed to GCV. A bystander effect, mediated by gap junctions, accounts for the transfer of toxic metabolites from TK-expressing cells to neighboring cells. It has been proposed that E-cadherin participates in the formation and function of such gap junctions. In this study we investigate the influence of E-cadherin on TK/GCV suicide therapy with a panel of cellular and in vivo models of pancreatic ductal adenocarcinoma. We observed a strong correlation of E-cadherin expression and the TK/GCV bystander effect, associated with the modulation of gap junction communication and connexin expression or localization. Importantly, the co-expression of TK and E-cadherin genes in the adenoviral vector AdTat8TKIE improved TK/GCV cytotoxicity and triggered a potent antitumoral effect, superior to standard AdTat8TK/GCV in MIAPaCa-2 xenografts. The increased expression of E-cadherin resulted in the reduction of the bcl-2 content. Interestingly, the knockdown of bcl-2 sensitized cells to TK/GCV. Thus, we propose that by restoring E-cadherin in pancreatic tumor cells we will improve TK/GCV therapy, both by enhancing the bystander effect and by facilitating the induction of apoptosis.

Vasoactive and antioxidant activities of plants used in Mexican traditional medicine for the treatment of cardiovascular diseases

This study demonstrated that the aqueous extracts of plants employed in Mexican traditional medicine for the treatment of cardiovascular diseases are able to modify the tone of arterial smooth muscle. Agastache mexicana (Kunth) Lint & Epling (Labiatae), Chenopodium murale L. (Chenopodiaceae), Chirantodendron pentadactylon Larreat (Sterculiaceae), Dracocephalum moldavica L. (Labiatae), Psittacanthus calyculatus G. Don (Loranthaceae), Prunus serotina ssp. capuli (Cav. ex Spreng) McVaugh (Rosaceae), and Sechium edule Sw. (Cucurbitaceae) contain secondary metabolites that promote vascular relaxation and display antioxidant activities. As expected, their antioxidant effects showed a significant correlation with the polyphenolics content. However, a lower correlation was found between the antioxidant activity and the maximum vasodilatory effect, suggesting that the vasodilatation elicited by the plant extracts could be only partly attributed to their antioxidant properties. The extract of P. calyculatus, which displayed a maximum vasorelaxant effect that was higher than that of acetylcholine, induced endothelium-dependent vasodilatation. Futhermore, the vasorelaxant response to the P. calyculatus extract was reduced after adding an inhibitor of soluble guanylate cyclase activity, providing evidence that the NO/cGMP pathway is involved. On the other hand, the extracts of Bocconia frutescens L. (Papaveraceae), Magnolia grandiflora L. (Magnoliaceae), and Solanum rostratum Dunal (Solanaceae) induced concentration-dependent contraction of rat aortic rings, suggesting that these plants have potential health benefits for the treatment of ailments such as venous insufficiency. The pharmacological activities of the extracts studied provide scientific support for their ethnomedical use.

Specific pattern of flea antigen recognition by IgG subclass and IgE during the progression of papular urticaria caused by flea bite

BACKGROUND

Papular urticaria caused by flea bite presents clinical symptoms of a hypersensitivity reaction accompanied by skin lesions. However, the pattern of recognition by different antibody isotypes during the progression of the disease is unknown. This study evaluated variations in immunoglobulin E and immunoglobulin G subclass antibody responses to flea antigens during the progression of papular urticaria caused by flea bite

METHODS

Twenty-five patients clinically diagnosed with papular urticaria due to flea bite were included. Ten healthy children were included as controls. Recognition of antigens from complete flea body extract by patients and healthy controls was determined using immunoblot assays.

RESULTS

The results revealed that patients with 2-5 years of papular urticaria evidenced more IgE bands than those with shorter or longer durations of symptoms. In contrast, healthy children showed a predominance of immunoglobulin G1 and immunoglobulin G3. The majority of the recognised antigens were low molecular weight proteins (<90 kDa). Proteins with molecular weights between 16-20, 21-25, and 31-35 kDa showed different patterns of recognition between patients and healthy children.

CONCLUSION

The predominant specific antibody isotypes vary according to the time elapsed since the onset of symptoms in papular urticaria caused by flea bite.

Phytoestrogens possess a weak antioxidant activity on low density lipoprotein in contrast to the flavonoid quercetinin vitroin postmenopausal women

BACKGROUND

Phytoestrogens are a family of plant-derived compounds with weak estrogenic and antiestrogenic properties. The antioxidant capacity of phytoestrogens has been proposed as one of the important mechanisms that explain their health benefits.

OBJECTIVE

To determine the in vitro potency of three phytoestrogens, ubiquitous in food, (biochanin A, daidzein and genistein) as antioxidants of low density lipoprotein (LDL) and to compare them with the well-established antioxidant actions of estradiol and quercetin, an ubiquitous flavonoid which is found in high concentration in onions, tea and berries.

METHODS

LDL was isolated by ultracentrifugation from the plasma of ten healthy postmenopausal women who were not on hormone therapy. Aliquots containing 0.5 mg of protein were incubated for 4 h with CuSO4 15 micromol/l to induce oxidative stress and with one of the five compounds studied: estradiol, quercetin, biochanin A, daidzein, and genistein, in doses of 0, 5, 15, 50, 500, 1000 and 2000 micromol/l. In addition, we studied the combined effect of estradiol 1 micromol/l plus quercetin 1 micromol/l, comparing their antioxidant action with that of each compound separately. Malonaldehyde (MDE nmol/ mg protein) was measured as a marker of LDL oxidation.

RESULTS

Estradiol and quercetin induced a dose-dependent decrease in MDE concentration (p < 0.01). Comparing the areas under the curve, the antioxidant effect of quercetin was 8 times higher than the one observed with estradiol (p < 0.01). A 50% decrease in MDE was reached by quercetin at a concentration of 3.4 micromol/l, estradiol at 29 micromol/l, genistein at 280 micromol/l, biochanin at 1312 mmol/l and daidzein at 8007 mmol/l. Estradiol 1 micromol/l and quercetin 1 micromol/l did not modify MDE generation separately, but, when incubated combined, there was a significant decrease of MDE (p < 0.02).

CONCLUSION

The phytoestrogens studied showed a weak antioxidant activity in vitro. The flavonoid quercetin, in contrast, showed the most potent antioxidant activity in vitro, higher than estradiol. Estradiol and quercetin showed additive antioxidant activity. We speculate that different compounds with variable antioxidant effects could amplify their antioxidant capacity when acting combined.

Fueling inflammation at tumor microenvironment: the role of multiligand/RAGE axis

The receptor for advanced glycation end products (RAGE), firstly described in 1992, is a single-transmembrane and multiligand member of the immunoglobulin protein family. RAGE engagement produces activation of multiple intracellular signaling mechanisms involved in several inflammation-associated clinical entities, such as diabetes, cancer, renal and heart failures, as well as neurodegenerative diseases. Although RAGE expression has been extensively reported in many cancer types, it is now emerging as a relevant element that can continuously fuel an inflammatory milieu at the tumor microenvironment, thus changing our perception of its contribution to cancer biology. In this review, we will discuss the role of multiligand/RAGE axis, particularly at the multicellular cross talk established in the inflammatory tumor microenvironment. A better understanding of its contribution may provide new targets for tumor management and risk assessment.