ß-cell function is associated with metabolic syndrome in Mexican subjects.

AIMS: The clinical diagnosis of metabolic syndrome does not find any parameters to evaluate the insulin sensitivity (IS) or ß-cell function. The evaluation of these parameters would detect early risk of developing metabolic syndrome. The aim of this study is to determine the relationship between ß-cell function and presence of metabolic syndrome in Mexican subjects. MATERIAL AND METHODS: This study is part of the Mexican Survey on the Prevention of Diabetes (MexDiab Study) with headquarters in the city of Puebla, Mexico. The study comprised of 444 subjects of both genders, aged between 18 and 60 years and allocated into two study groups: (1) control group of individuals at metabolic balance without metabolic syndrome and (2) group composed of subjects with metabolic syndrome and diagnosed according to the criteria of the Third Report of the National Cholesterol Education Program Expert Panel on Defection, Evaluation, and Treatment of High Blood Cholesterol in Adults. Anthropometric, biochemical, and clinical assessments were carried out. RESULTS: Average age of the subjects in the control group (n = 254) was 35.7 ± 11.5 years and 42.0 ± 10.7 years for subjects in the metabolic syndrome group (n = 190). Subjects at metabolic balance without metabolic syndrome showed decreased IS, increased insulin resistance (IR), and altered ß-cell function. Individuals with metabolic syndrome showed a high prevalence (P ≤ 0.05) of family history of type 2 diabetes (T2D). This group also showed a significant metabolic imbalance with glucose and insulin levels and lipid profile outside the ranges considered safe to prevent the development of cardiovascular disease and T2D. CONCLUSION: The main finding in this study was the detection of altered ß-cell function, decreased IS, an increased IR in subjects at metabolic balance, and the progressive deterioration of ß-cell function and IS in subjects with metabolic syndrome as the number of features of metabolic syndrome increases.

Clinical forms of Trypanosoma cruzi infected individuals in the chronic phase of Chagas disease in Puebla, Mexico.

In Mexico, despite the relatively high seroprevalence of Trypanosoma cruzi infection in humans in some areas, reported morbidity of Chagas disease is not clear. We determined clinical stage in 71 individuals seropositive to T. cruzi in the state of Puebla, Mexico, an area endemic for Chagas disease with a reported seroprevalence of 7.7%. Diagnosis of Chagas disease was made by two standardized serological tests (ELISA, IHA). Individuals were stratified according to clinical studies. All patients were submitted to EKG, barium swallow, and barium enema. Groups were identified as indeterminate form (IF) asymptomatic individuals without evidence of abnormalities (n = 34 cases); those with gastrointestinal alterations (12 patients) including symptoms of abnormal relaxation of the lower esophageal sphincter and absent peristalsis in the esophageal body, grade I megaesophagus, and/or megacolon; patients with clinical manifestations and documented changes of chronic Chagas heart disease who were subdivided as follows: mild (8 patients)--mild electrocardiographic changes of ventricular repolarization, sinus bradychardia); moderate (6 patients)--left bundle branch block, right bundle branch block associated with left anterior fascicular block); severe (8 patients)--signs of cardiomegaly, dilated cardiomyopathy); and the associated form (3 cases) that included presence of both cardiomyopathy and megaesophagus. These data highlight the importance of accurate evaluation of the prevalence and clinical course of Chagas disease in endemic and non-endemic areas of Mexico.

Clinical forms of Trypanosoma cruzi infected individuals in the chronic phase of Chagas disease in Puebla, Mexico

In Mexico, despite the relatively high seroprevalence of Trypanosoma cruzi infection in humans in some areas, reported morbidity of Chagas disease is not clear. We determined clinical stage in 71 individuals seropositive to T. cruzi in the state of Puebla, Mexico, an area endemic for Chagas disease with a reported seroprevalence of 7.7 percent. Diagnosis of Chagas disease was made by two standardized serological tests (ELISA, IHA). Individuals were stratified according to clinical studies. All patients were submitted to EKG, barium swallow, and barium enema. Groups were identified as indeterminate form (IF) asymptomatic individuals without evidence of abnormalities (n = 34 cases); those with gastrointestinal alterations (12 patients) including symptoms of abnormal relaxation of the lower esophageal sphincter and absent peristalsis in the esophageal body, grade I megaesophagus, and/or megacolon; patients with clinical manifestations and documented changes of chronic Chagas heart disease who were subdivided as follows: mild (8 patients) - mild electrocardiographic changes of ventricular repolarization, sinus bradychardia); moderate (6 patients) - left bundle branch block, right bundle branch block associated with left anterior fascicular block); severe (8 patients) - signs of cardiomegaly, dilated cardiomyopathy); and the associated form (3 cases) that included presence of both cardiomyopathy and megaesophagus. These data highlight the importance of accurate evaluation of the prevalence and clinical course of Chagas disease in endemic and non-endemic areas of Mexico.

Trypanosoma cruzi strains isolated from human, vector, and animal reservoir in the same endemic region in Mexico and typed as T. cruzi I, discrete typing unit 1 exhibit considerable biological diversity.

In this study, three strains of Trypanosoma cruzi were isolated at the same time and in the same endemic region in Mexico from a human patient with chronic chagasic cardiomyopathy (RyC-H); vector (Triatoma barberi) (RyC-V); and rodent reservoir (Peromyscus peromyscus) (RyC-R). The three strains were characterized by multilocus enzyme electrophoresis, random amplified polymorphic DNA, and by pathological profiles in experimental animals (biodemes). Based on the analysis of genetic markers the three parasite strains were typed as belonging to T. cruzi I major group, discrete typing unit 1. The pathological profile of RyC-H and RyC-V strains indicated medium virulence and low mortality and, accordingly, the strains should be considered as belonging to biodeme Type III. On the other hand, the parasites from RyC-R strain induced more severe inflammatory processes and high mortality (> 40%) and were considered as belonging to biodeme Type II. The relationship between genotypes and biological characteristics in T. cruzi strains is still debated and not clearly understood. An expert committee recommended in 1999 that Biodeme Type III would correspond to T. cruzi I group, whereas Biodeme Type II, to T. cruzi II group. Our findings suggest that, at least for Mexican isolates, this correlation does not stand and that biological characteristics such as pathogenicity and virulence could be determined by factors different from those identified in the genotypic characterization.

Trypanosoma cruzi strains isolated from human, vector, and animal reservoir in the same endemic region in Mexico and typed as T. cruzi I, discrete typing unit 1 exhibit considerable biological diversity

In this study, three strains of Trypanosoma cruzi were isolated at the same time and in the same endemic region in Mexico from a human patient with chronic chagasic cardiomyopathy (RyC-H); vector (Triatoma barberi) (RyC-V); and rodent reservoir (Peromyscus peromyscus) (RyC-R). The three strains were characterized by multilocus enzyme electrophoresis, random amplified polymorphic DNA, and by pathological profiles in experimental animals (biodemes). Based on the analysis of genetic markers the three parasite strains were typed as belonging to T. cruzi I major group, discrete typing unit 1. The pathological profile of RyC-H and RyC-V strains indicated medium virulence and low mortality and, accordingly, the strains should be considered as belonging to biodeme Type III. On the other hand, the parasites from RyC-R strain induced more severe inflammatory processes and high mortality (> 40 percent) and were considered as belonging to biodeme Type II. The relationship between genotypes and biological characteristics in T. cruzi strains is still debated and not clearly understood. An expert committee recommended in 1999 that Biodeme Type III would correspond to T. cruzi I group, whereas Biodeme Type II, to T. cruzi II group. Our findings suggest that, at least for Mexican isolates, this correlation does not stand and that biological characteristics such as pathogenicity and virulence could be determined by factors different from those identified in the genotypic characterization

Severity of chronic Chagas disease is associated with cytokine/antioxidant imbalance in chronically infected individuals.

Understanding the pathogenic mechanisms in chronic Chagas disease, a major cause of morbidity and mortality in Latin America, is essential for the design of rational therapeutic strategies. In this paper we show that the development of Chagas disease is a consequence of a long-term and complex relationship between parasite persistence and maladapted homeostatic mechanisms in the host which leads to pathologic changes. We performed a retrospective study on 50 patients with chronic Chagas disease and 50 healthy control individuals. The specific immune response was detected by ELISA and IHA tests using autochthonous antigens, inflammatory process with the cytokine tumour necrosis factor (TNF)-alpha and nitric oxide (NO), and antioxidant protection with glutathione peroxidase and superoxide dismutase (SOD) levels. We developed generalised linear modelling procedures to assess simultaneously which explanatory variables and/or their interactions better explained disease severity in patients. Our results show the existence of a strong relationship between anti-Trypanosoma cruzi levels and chronic Chagas disease (P<0.0001). Taken together, the statistical data indicate both cumulative and complementary effects, where the increase in TNF-alpha (P=0.004) and NO (P=0.005) levels correlated with a reduction in glutathione peroxidase (P=0.0001) and SOD (P=0.01) levels drives the disease pathology in chronically infected patients. Our findings may have important implications for understanding host susceptibility to develop severe chronic infectious disease. In addition we show putative targets for the design of new therapeutic strategies to prevent disease progression, considering both specific treatment against the aetiological agent and modulation of the different immunopathological reactions in chronically infected individuals with chronic Chagas disease.

Differentiation of entamoeba histolytica/entamoeba dispar by PCR and their correlation with humoral and cellular immunity in individuals with clinical variants of amoebiasis.

To correlate a particular state of immunity with Entamoeba spp., we used colorimetric PCR to differentiate E. histolytica from E. dispar in individuals with amoebiasis and to associate its presence with the clinical profile, including humoral and cellular immune responses to E. histolytica. Our results showed high levels of antibody in acute amoebiasis and elevation of IL-4 production, a cytokine related to Th2 profile, associated with E. histolytica. In chronic amoebiasis, even with anti-E. histolytica seropositivity, intestinal symptoms were associated with E. dispar in all the cases, without differences in level of antibodies, BTI, CD4+/CD8+ ratio, INF-gamma, and IL-4. Among asymptomatic carriers, E. dispar was more frequently found; however, identification of E. histolytica in two asymptomatic carriers associated with high levels of INF-gamma, a cytokine related to Th1 profile, demonstrate the importance of making specific diagnosis of Entamoeba spp., to establish the clinical and epidemiological behavior in both intestinal and extra-intestinal amoebiasis.