José Pedrazzoli

Prevalence of Helicobacter pylori Resistance to Metronidazole, Clarithromycin, Amoxicillin, Tetracycline, and Furazolidone in Brazil

Background. Helicobacter pylori infection is associated with a wide range of digestive diseases and is very prevalent in developing countries, although few data exist on the susceptibility of H. pylori to antimicrobials commonly used in eradication schedules in these countries. The aim of this study was to evaluate the resistance of H. pylori to metronidazole, clarithromycin, amoxicillin, tetracycline, and furazolidone in dyspeptic Brazilian patients.

Antiobesity effects of yerba maté extract (Ilex paraguariensis) in high-fat diet-induced obese mice.

Because the potential of yerba maté (Ilex paraguariensis) has been suggested in the management of obesity, the aim of the present study was to evaluate the effects of yerba maté extract on weight loss, obesity‐related biochemical parameters, and the regulation of adipose tissue gene expression in high‐fat diet–induced obesity in mice. Thirty animals were randomly assigned to three groups. The mice were introduced to standard or high‐fat diets. After 12 weeks on a high‐fat diet, mice were randomly assigned according to the treatment (water or yerba maté extract 1.0 g/kg). After treatment intervention, plasma concentrations of total cholesterol, high‐density lipoprotein cholesterol, triglyceride, low‐density lipoprotein (LDL) cholesterol, and glucose were evaluated. Adipose tissue was examined to determine the mRNA levels of several genes such as tumor necrosis factor‐α (TNF‐α), leptin, interleukin‐6 (IL‐6), C‐C motif chemokine ligand‐2 (CCL2), CCL receptor‐2 (CCR2), angiotensinogen, plasminogen activator inhibitor‐1 (PAI‐1), adiponectin, resistin, peroxisome proliferator‐activated receptor‐γ2 (PPAR‐γ2), uncoupling protein‐1 (UCP1), and PPAR‐γ coactivator‐1α (PGC‐1α). The F4/80 levels were determined by immunoblotting. We found that obese mice treated with yerba maté exhibited marked attenuation of weight gain, adiposity, a decrease in epididymal fat‐pad weight, and restoration of the serum levels of cholesterol, triglycerides, LDL cholesterol, and glucose. The gene and protein expression levels were directly regulated by the high‐fat diet. After treatment with yerba maté extract, we observed a recovery of the expression levels. In conclusion, our data show that yerba maté extract has potent antiobesity activity in vivo. Additionally, we observed that the treatment had a modulatory effect on the expression of several genes related to obesity.

Protective effects of mate tea (Ilex paraguariensis) on H2O2-induced DNA damage and DNA repair in mice

Yerba mate (Ilex paraguariensis) is rich in several bioactive compounds that can act as free radical scavengers. Since oxidative DNA damage is involved in various pathological states such as cancer, the aim of this study was to evaluate the antioxidant activity of mate tea as well as the ability to influence DNA repair in male Swiss mice. Forty animals were randomly assigned to four groups. The animals received three different doses of mate tea aqueous extract, 0.5, 1.0 or 2.0 g/kg, for 60 days. After intervention, the liver, kidney and bladder cells were isolated and the DNA damage induced by H(2)O(2) was investigated by the comet assay. The DNA repair process was also investigated for its potential to protect the cells from damage by the same methodology. The data presented here show that mate tea is not genotoxic in liver, kidney and bladder cells. The regular ingestion of mate tea increased the resistance of DNA to H(2)O(2)-induced DNA strand breaks and improved the DNA repair after H(2)O(2) challenge in liver cells, irrespective of the dose ingested. These results suggest that mate tea could protect against DNA damage and enhance the DNA repair activity. Protection may be afforded by the antioxidant activity of the mate teas bioactive compounds.

Analysis of antimicrobial susceptibility and virulence factors in Helicobacter pylori clinical isolates

BackgroundIn this study, we evaluated the prevalence of primary resistance of Brazilian H. pylori isolates to metronidazole, clarithromycin, amoxicillin, tetracycline, and furazolidone. In addition, the vacA, iceA, cagA and cagE genotypes of strains isolated from Brazilian patients were determined and associated with clinical data in an effort to correlate these four virulence markers and antibiotic resistance.MethodsH. pylori was cultured in 155 H. pylori-positive patients and MICs for metronidazole, clarithromycin, amoxicillin, tetracycline, and furazolidone were determined by the agar dilution method. Genomic DNA was extracted, and allelic variants of vacA, iceA, cagA and cagE were identified by the polymerase chain reaction.ResultsThere was a strong association between the vacA s1/cagA -positive genotype and peptic ulcer disease (OR = 5.42, 95% CI 2.6–11.3, p = 0.0006). Additionally, infection by more virulent strains may protect against GERD, since logistic regression showed a negative association between the more virulent strain, vacA s1/cagA-positive genotype and GERD (OR = 0.26, 95% CI 0.08–0.8, p = 0.03). Resistance to metronidazole was detected in 75 patients (55%), to amoxicillin in 54 individuals (38%), to clarithromycin in 23 patients (16%), to tetracycline in 13 patients (9%), and to furazolidone in 19 individuals (13%). No significant correlation between pathogenicity and resistance or susceptibility was detected when MIC values for each antibiotic were compared with different vacA, iceA, cagA and cagE genotypes.ConclusionThe analysis of virulence genes revealed a specific association between H. pylori strains and clinical outcome, furthermore, no significant association was detected among pathogenicity and resistance or susceptibility.

Anti-inflammatory effects of yerba mate extract (Ilex paraguariensis) ameliorate insulin resistance in mice with high fat diet-induced obesity

The aim of the present study was to evaluate the effects of yerba maté extract upon markers of insulin resistance and inflammatory markers in mice with high fat diet-induced obesity. The mice were introduced to either standard or high fat diets. After 12 weeks on a high fat diet, mice were randomly assigned to one of the two treatment conditions, water or yerba maté extract at 1.0 gkg(-1). After treatment, glucose blood level and hepatic and soleus muscle insulin response were evaluated. Serum levels of TNF-α and IL-6 were evaluated by ELISA, liver tissue was examined to determine the mRNA levels of TNF-α, IL-6 and iNOS, and the nuclear translocation of NF-κB was determined by an electrophoretic mobility shift assay. Our data show improvements in both the basal glucose blood levels and in the response to insulin administration in the treated animals. The molecular analysis of insulin signalling revealed a restoration of hepatic and muscle insulin substrate receptor (IRS)-1 and AKT phosphorylation. Our data show that the high fat diet caused an up-regulation of the TNF-α, IL-6, and iNOS genes. Although after intervention with yerba maté extract the expression levels of those genes returned to baseline through the NF-κB pathway, these results could also be secondary to the weight loss observed. In conclusion, our results indicate that yerba maté has a potential anti-inflammatory effect. Additionally, these data demonstrate that yerba maté inhibits hepatic and muscle TNF-α and restores hepatic insulin signalling in mice with high fat diet-induced obesity.

Mesenteric adipose tissue alterations resulting from experimental reactivated colitis.

Background: Adipose tissue secretes a large number of hormones that act either locally or at distant sites, modulating immune responses, inflammation, and many endocrine and metabolic functions. Abnormalities of fat in the mesentery have been long recognized in surgical specimens as characteristic features of Crohns disease; however, the importance of this in chronic inflammatory disease is unknown. Additionally, adipocytes in depots that enclose lymph nodes or other dense masses of lymphoid tissue have many site‐specific physiological properties. Methods: In this study, the alterations of mesenteric and perinodal mesenteric adipose tissue during experimental colitis, induced by repeated intracolonic trinitrobenzene sulfonic acid instillations, were evaluated, focusing on morphological and activity alterations and the adipocytokine production profile. Results: After a 35‐day protocol, the colitis animals presented greater mesenteric fat masses despite their lower body weights. Another adipose tissue depot, epididymal adipose tissue, was also evaluated and no change in mass was observed. The mesenteric adipocyte from colitis animals had a reduced diameter, normal PPAR‐&ggr;‐2 expression, and higher basal lipolysis and TNF‐&agr; production when compared to normal rats. Perinodal mesenteric adipocytes present normal diameters, downregulated levels of PPAR‐&ggr;‐2, higher basal lipolysis and TNF‐&agr;, and leptin and adiponectin production. Conclusions: The findings suggest that mesenteric adipose tissue has a site‐specific response during experimental inflammation, where perinodal adipose tissue retains the ability to produce different adipocytokines. These substances may interfere in many lymph node aspects, while mesenteric adipose tissue produces substances that could contribute directly to aggravate the inflammatory process.

Detection of high‐level tetracycline resistance in clinical isolates of Helicobacter pylori using PCR‐RFLP

Tetracycline is one of four antibiotics commonly used for the treatment of Helicobacter pylori infection, but its effectiveness is decreasing as the incidence of tetracycline resistance is increasing. In five Brazilian tetracycline-resistant (Tet(R)) H. pylori isolates, high-level tetracycline resistance is mediated by the triple-base-pair substitution AGA(926-928)-->TTC in both 16S rRNA genes, as was previously observed in two independent high-level Tet(R) H. pylori strains. A polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) assay was developed for the detection of the AGA(926-928)-->TTC substitution, and confirmed the presence of the aforementioned triple-base-pair substitution in all five Brazilian Tet(R) isolates. This PCR-RFLP-based approach distinguishes the high-level Tet(R) isolates from low-level Tet(R) and Tet(S) H. pylori strains and thus allows the direct detection of Tet(R) H. pylori isolates.

Effect of Helicobacter pylori infection on IL-8, IL-1β and COX-2 expression in patients with chronic gastritis and gastric cancer

Objective. Helicobacter pylori infection is related to gastric cancer development, and chronic inflammation is presumed to be the main cause. The aim of the present study was to evaluate the influence of H. pylori cagA, vacA, iceA, and babA genotypes on COX-2, IL-1β, and IL-8 expression. Material and methods. Of the 217 patients included in the study, 26 were uninfected, 127 had chronic gastritis and were H. pylori-positive, and 64 had gastric cancer. Bacterial genotypes were evaluated by polymerase chain reaction (PCR), and the expression values were determined by quantitative real-time PCR and immunohistochemistry. Results. An association was found between the infection with cagA, vacA s1m1 strains and gastric cancer development. Regarding the 3′ region of the cagA gene, we also found an association between the infection with cagA EPIYA-ABCCC strains and clinical outcome. Higher levels of IL-8, IL-1β, and COX-2 were detected in gastric mucosa from infected patients with chronic gastritis, and they were also associated with the infection by cagA, vacA s1m1 strains. The IL-8 and IL-1β levels decrease significantly from chronic gastritis to gastric cancer, while the relative expression remained unaltered when COX-2 expression was analyzed among patients with gastritis and cancer. Conclusions. Since inflammatory response to H. pylori infection plays an important role in cellular proliferation and gastric mucosal damage, the up-regulation of IL-1β, IL-8, and COX-2 in patients with chronic gastritis has an important clinical implication in gastric carcinogenesis.

Analysis of Oxidative DNA Damage in Patients with Colorectal Cancer

PURPOSE The aim of this study was to measure the levels of oxidative DNA damage in cells isolated from the colon mucosa in patients with colorectal cancer and to compare normal and neoplastic tissues and make correlations with anatomopathologic variables. PATIENTS AND METHODS Thirty-three patients with colorectal adenocarcinoma were studied. The oxidative DNA damage was evaluated by means of the alkaline version of the comet assay. RESULTS For all the patients studied, it was found that the cells obtained from the neoplastic tissue presented oxidative DNA damage greater than in the cells from normal tissue. The cells isolated from the neoplastic mucosal tissue of the colon presented significantly greater mean extent of DNA strand breakage than the cells isolated from normal tissue. Additionally, the patients at earlier stages of the Dukes and TNM classifications presented higher levels of oxidative damage than those at more advanced stages. CONCLUSION Assessment of the levels of oxidative damage at the different stages of colorectal carcinogenesis is of great interest because it enables evaluation of the effectiveness of antioxidant substances that could be used as preventive measures against the initial oxidative aggressive action on the colonic mucosa.

Multiple mutations in or adjacent to the conserved penicillin-binding protein motifs of the penicillin-binding protein 1A confer amoxicillin resistance to Helicobacter pylori

Background:  Amoxicillin‐based therapies are highly effective for the treatment of Helicobacter pylori infections, but the efficacy may decrease as the incidence of amoxicillin resistance is increasing. So far, the molecular mechanism underlying stable amoxicillin resistance has only been identified for a few naturally occurring amoxicillin‐resistant (AmxR) H. pylori isolates, and is mediated by mutations in penicillin‐binding protein 1A (PBP1A). In this study the molecular mechanism underlying amoxicillin resistance of seven additional AmxR H. pylori isolates has been established.