Humans seropositive for Trypanosoma cruzi co-infected with intestinal helminths have higher infectiousness, parasitaemia and Th2-type response in the Argentine Chaco.

BACKGROUND: The Gran Chaco ecoregion is a well-known hotspot of several neglected tropical diseases (NTDs) including Chagas disease, soil-transmitted helminthiasis and multiparasitic infections. Interspecific interactions between parasite species can modify host susceptibility, pathogenesis and transmissibility through immunomodulation. Our objective was to test the association between human co-infection with intestinal parasites and host parasitaemia, infectiousness to the vector and immunological profiles in Trypanosoma cruzi-seropositive individuals residing in an endemic region of the Argentine Chaco. METHODS: We conducted a cross-sectional serological survey for T. cruzi infection along with an intestinal parasite survey in two adjacent rural villages. Each participant was tested for T. cruzi and Strongyloides stercoralis infection by serodiagnosis, and by coprological tests for intestinal parasite detection. Trypanosoma cruzi bloodstream parasite load was determined by quantitative PCR (qPCR), host infectiousness by artificial xenodiagnosis and serum human cytokine levels by flow cytometry. RESULTS: The seroprevalence for T. cruzi was 16.1% and for S. stercoralis 11.5% (n = 87). We found 25.3% of patients with Enterobius vermicularis. The most frequent protozoan parasites were Blastocystis spp. (39.1%), Giardia lamblia (6.9%) and Cryptosporidium spp. (3.4%). Multiparasitism occurred in 36.8% of the examined patients. Co-infection ranged from 6.9% to 8.1% for T. cruzi-seropositive humans simultaneously infected with at least one protozoan or helminth species, respectively. The relative odds of being positive by qPCR or xenodiagnosis (i.e. infectious) of 28 T. cruzi-seropositive patients was eight times higher in people co-infected with at least one helminth species than in patients with no such co-infection. Trypanosoma cruzi parasite load and host infectiousness were positively associated with helminth co-infection in a multiple regression analysis. Interferon-gamma (IFN-γ) response, measured in relation to interleukin (IL)-4 among humans infected with T. cruzi only, was 1.5-fold higher than for T. cruzi-seropositive patients co-infected with helminths. The median concentration of IL-4 was significantly higher in T. cruzi-seropositive patients with a positive qPCR test than in qPCR-negative patients. CONCLUSIONS: Our results show a high level of multiparasitism and suggest that co-infection with intestinal helminths increased T. cruzi parasitaemia and upregulated the Th2-type response in the study patients.

Development of a PCR assay for identification of Neobalantidium coli () in Argentina.

Neobalantidium coli (Pomajbíková et al., 2013) is a cosmopolitan ciliate which colonizes the intestine of humans and animals. Pigs are the most important host and reservoir for this parasite, although others mammals have been described. Humans can acquire the disease through the ingestion of water and food contaminated with cysts and even from person to person contact. Farmers and slaughterhouse workers from rural areas of developing countries have an increased incidence of balantidiosis. In Argentina, despite swine production on family farms covers 70% of domestic consumption requirements; there is a lack of veterinary animal health planning which result in high rate of animal mortality, as well as environmental risk due to inefficient facilities and mismanagement of manure and effluents. At present there are no epidemiological data on balantidiosis in Argentina, except for isolated reports. Therefore, the aims of this study were to establish the frequency of N. coli in pigs raised under different conditions and to explore the zoonotic potential. In order to confirm the identity of Neobalantidium coli like-cysts founded in the feces, a set of N. coli specific primers based on 18S rRNA gene sequences was designed. The molecular identification of N. coli was performed in 88.9% (16 out of 18) of swine stool samples in which cysts had been visualized. The fecal samples obtained from pigs raised on more open farmland showed a lower percentage of N. coli than those obtained from animals raised in swine pens. On the other hand, molecular identification of N. coli was also performed in human feces. Pairwise comparison of sequences obtained from pigs and human fecal samples from the NW Region of Argentina showed a high percentage of similarity, indicating a possible zoonotic transmission.

Social and environmental health determinants and their relationship with parasitic diseases in asymptomatic children from a shantytown in Buenos Aires, Argentina.

Health inequities are a common problem for all countries and are the result of not only adverse social conditions but also poor public policies. Today chronic diseases represent the most relevant threats and are a current challenge. Parasitic infections, a leading cause of child morbidity affecting low-income populations, can be transmitted because of an unhealthy environment. Notwithstanding, scarce data have been published on the epidemiological profile of intestinal parasitoses in asymptomatic children living in shantytowns. Vulnerable populations settled in slums are growing in Argentina, particularly in Buenos Aires city. Consequently, this work intended to screen healthy carriers of enteric parasites and determine the epidemiologic profile in asymptomatic children residing in one of those communities, to explore risk factors associated with the transmission of parasites, and to initiate a basic health education campaign to promote healthy behavior in the community. Fecal samples (n = 138) were analyzed by conventional parasitological methods and a survey gathered data on symptoms, family composition, and environmental and hygiene-related variables. High prevalence of feco-orally-transmitted parasitoses (83·3%) and polyparasitism were remarkable findings. The main environmental health determinants were those related to excreta disposal and water provision. Health promotion actions were performed through the diffusion of a set of posters with iconic images and brief messages for health education. Results suggest the need for an environmental sanitation policy to complement health promotion actions. It is essential to spread the results of investigations that address inequities and social determinants of health in order to integrate data with local political processes and alert on acceptable actions for developing appropriate interventions.

Overcoming language and cultural barriers: a graphical communication tool to perform a parasitological screening in two vulnerable populations from Argentina.

This is an exploratory study of the application of a support tool for the detection of asymptomatic subjects carrying enteric parasites in two vulnerable populations in Argentina: a shantytown in the city of Buenos Aires and a rural Wichí indigenous community in the province of Chaco. The ethnic and cultural diversity, high illiteracy rate, and language barriers called for the development of an auxiliary resource to explain stool sample collection procedures. In individual interviews with each family, the authors used two instructional guidance leaflets in comic strip format depicting the procedures. They evaluated the acceptance of the graphical communication tool on the basis of the number of retrieved samples. Percentages of respondent families were 72.2% and 66.7%, respectively. Definitive validation of these instruments would allow their use in community studies, community service learning experiences, and research on aboriginal communities that would otherwise be excluded from studies on health status.

Flow cytometry to evaluate Anaplasma marginale parasitemia using a fluorescent nucleic acid stain.

In this work we describe a flow cytometry-based method using SYTO16 (a DNA intercalating agent) to quantify Anaplasma marginale-infected erythrocytes in blood from bovine animals. The linearity and reproducibility of the results obtained with SYTO16 labeling followed by flow cytometry analysis make it a suitable approach for measurement of parasitemia in A. marginale infections.

Aluminum exposure affects transferrin-dependent and -independent iron uptake by K562 cells.

Aluminum (Al) and iron (Fe) share several physicochemical characteristics and they both bind to transferrin (Tf), entering the cell via Tf receptors (TfR). Previously, we found similar values of affinity constant for the binding of TfR to Tf carrying either Al or Fe. The competitive interaction between both metals prevented normal Fe incorporation into K562 cells and triggered the upregulation of Fe transport. In the present work we demonstrated that Al modified Fe uptake without affecting the expression of Tf receptors. Both TfR and TfR2 mRNA levels, evaluated by RT-PCR, and TfR antigenic sites, analyzed by flow cytometry, were found unchanged after Al exposure. In turn, Al did induce upregulation of non-Tf bound Fe (NTBI) uptake. This modulation was not due to intracellular Fe decrease since NTBI transport proved not to be regulated by Fe depletion. Unlike its behavior in the presence of Tf, Al was unable to compete with NTBI uptake, suggesting that both metals do not share the same alternative transport pathway. We propose that Al interference with TfR-mediated Fe incorporation might trigger the upregulation of NTBI uptake, an adaptation aimed at incorporating the essential metal required for cellular metabolism without allowing the simultaneous access of a potentially toxic metal.

The distinct erythropoietin functions that promote cell survival and proliferation are affected by aluminum exposure through mechanisms involving erythropoietin receptor.

Erythropoietin (Epo) promotes the development of erythroid progenitors by triggering intracellular signals through the binding to its specific receptor (EpoR). Previous results related to the action of aluminum (Al) on erythropoiesis let us suggest that the metal affects Epo interaction with its target cells. In order to investigate this effect on cell activation by the Epo-EpoR complex, two human cell lines with different dependence on Epo were subjected to Al exposure. In the Epo-independent K562 cells, Al inhibited Epo antiapoptotic action and triggered a simultaneous decrease in protein and mRNA EpoR levels. On the other hand, proliferation of the strongly Epo-dependent UT-7 cells was enhanced by long-term Al treatment, in agreement with the upregulation of EpoR expression during Epo starvation. Results provide some clues to the way by which Epo supports cell survival and growth, and demonstrate that not all the intracellular factors needed to guarantee the different signaling pathways of Epo-cell activation are available or activated in cells expressing EpoR. This study then suggests that at least one of the mechanisms by which Al interfere with erythropoiesis might involve EpoR modulation.

Toxicidad del aluminio sobre el sistema eritropoyético: mecanismos involucrados / Aluminum toxicity in erythropoiesis: related mechanisms

En la presente revisión se expone una discusión de resultados publicados que involucran al aluminio como uno de los factores que pueden afectar al sistema eritropoyético. En células K562 se determinó que el receptor específico para transferrina presente en la membrana de células eritroides posee afinidad similar para esa proteína cuando transporta hierro o aluminio y que la captación celular de hierro disminuye por la presencia de aluminio. Este metal provoca, en células eritroides, una disminución de la síntesis de hemoglobina. En base a los resultados obtenidos en estudios experimentales in vitro e in vivo se postulan dos hipótesis que involucran: la interferencia del aluminio con la captación y/o utilización celular de hierro y la interacción del aluminio con componentes de la membrana celular. Este último hecho afectaría no sólo la estructura de la membrana sino también sus características fisicoquímicas y/o sus funciones, como la unión de ligandos a sus receptores específicos de la superficie de la membrana celular. Los mecanismos que se discuten permiten adjudicar a la presencia de aluminio en el organismo tanto la inhibición del crecimiento y/o la diferenciación de células progenitoras eritroides como las diferentes alteraciones morfológicas de eritrocitos maduros (AU)

Toxicidad del aluminio sobre el sistema eritropoyético: mecanismos involucrados / Aluminum toxicity in erythropoiesis: related mechanisms

En la presente revisión se expone una discusión de resultados publicados que involucran al aluminio como uno de los factores que pueden afectar al sistema eritropoyético. En células K562 se determinó que el receptor específico para transferrina presente en la membrana de células eritroides posee afinidad similar para esa proteína cuando transporta hierro o aluminio y que la captación celular de hierro disminuye por la presencia de aluminio. Este metal provoca, en células eritroides, una disminución de la síntesis de hemoglobina. En base a los resultados obtenidos en estudios experimentales in vitro e in vivo se postulan dos hipótesis que involucran: la interferencia del aluminio con la captación y/o utilización celular de hierro y la interacción del aluminio con componentes de la membrana celular. Este último hecho afectaría no sólo la estructura de la membrana sino también sus características fisicoquímicas y/o sus funciones, como la unión de ligandos a sus receptores específicos de la superficie de la membrana celular. Los mecanismos que se discuten permiten adjudicar a la presencia de aluminio en el organismo tanto la inhibición del crecimiento y/o la diferenciación de células progenitoras eritroides como las diferentes alteraciones morfológicas de eritrocitos maduros

Human erythroid cells are affected by aluminium. Alteration of membrane band 3 protein.

There is evidence that anaemia is associated with aluminium (Al). We have already reported on the sensitivity to Al, showed by erythroid cell populations of animals chronically exposed to the metal. In order to investigate whether Al could also affect human cells, experiments were carried out both on immature and mature human erythroid cells. Erythroid progenitors (CFU-E, colony-forming units-erythroid) concentrated from human peripheral blood were cultured in an Al-rich medium under erythropoietin stimulation and their development analysed. Human peripheral erythrocytes were aged in the presence of Al. Cells were examined using scanning electron microscopy, and membrane proteins analysed by polyacrylamide gel electrophoresis with sodium dodecyl sulphate and immunoblotting. The development of the Al-treated progenitors was 8750/6600-9200 CFU-E/10(6) cells, a significantly lower median value (P<0.05) than that showed by non-treated cells (12300/11200-20700 CFU-E/10(6) cells). Erythrocyte morphological changes were induced by Al during the in vitro ageing. The cells lost their typical biconcave shape, turning into acanthocytes and stomatocytes. Simultaneously, an increased membrane protein breakdown compatible with band 3 degradation was detected. Besides, Al was found within the cells and attached to the membrane. The present in vitro results suggest that Al may disturb human erythropoiesis through combined effects on mature erythrocytes and cellular metabolism in late erythroid progenitors.

The inhibitory action of chlorogenic acid on the intestinal iron absorption in rats

The polyphenols are part of the composition of many foods, it is known the inhibitory effect of tea and coffee through the tannins on iron intestinal absorption; the yerba mate (Ilex Paraguarensis) is a beverage widely used in South America, that has a high content of a polyphenol named chlorogenic acid. The present work shows the effect of this substance in nonhem iron absorption. An intestinal loop, was made in rats, to form a closed cavity in a small section of intestine tieing it from the pilorous to a distance of six cm. In this closed cavity a solution of 59Fe was injected with different doses of chlorogenic acid; it was living 20, 40 and 120 minutes into the loop, and after this different times, the blood, spleen, liver, femur and intestine were removed to measure the 59Fe uptake to be compared with the control group. The results gave an intense inhibitory effect on the intestinal iron absorption with doses of 0.58 and 1.7 mM per rat of chlorogenic acid at the different times studied (Au)

The inhibitory action of chlorogenic acid on the intestinal iron absorption in rats

The polyphenols are part of the composition of many foods, it is known the inhibitory effect of tea and coffee through the tannins on iron intestinal absorption; the yerba mate (Ilex Paraguarensis) is a beverage widely used in South America, that has a high content of a polyphenol named chlorogenic acid. The present work shows the effect of this substance in nonhem iron absorption. An intestinal loop, was made in rats, to form a closed cavity in a small section of intestine tieing it from the pilorous to a distance of six cm. In this closed cavity a solution of 59Fe was injected with different doses of chlorogenic acid; it was living 20, 40 and 120 minutes into the loop, and after this different times, the blood, spleen, liver, femur and intestine were removed to measure the 59Fe uptake to be compared with the control group. The results gave an intense inhibitory effect on the intestinal iron absorption with doses of 0.58 and 1.7 mM per rat of chlorogenic acid at the different times studied

Estandarización de un método analítico: aplicación a la determinación de glicosaminoaglicanos urinarios / Standardization of a analytical method: aplication to the determination of urinary glycosaminoglycans

Se presenta la estandarización de un método para la determinación cuantitativa de glicosaminoglicanos (GAGs) urinarios, empleando una combinación de los métodos descriptos por Di Ferrante y Bitter y Muir, con algunas modificaciones que debieron ser introducidas para adecuarlo a nuestras condiciones experimentales. La determinación se basa en la precipitación de los GAGs por acción de bromuro de cetiltrimetilamonio, seguida de la hidrólisis del polímero y la posterior reacción colorimétrica con carbazol de los ácidos hexurónicos liberados. Se describen, detalladamente, los estudios de estandarización: determinación de la precisión de las distintas etapas del método, linealidad y carta de control de las pendientes de las curvas de calibración, ensayos de recuperación, investigación de interferencias y variaciones en las condiciones de trabajo. Esta metodología puede servir de base para establecer protocolos de control de cualquier procedimiento analítico (AU)

Estandarización de un método analítico: aplicación a la determinación de glicosaminoaglicanos urinarios / Standardization of a analytical method: aplication to the determination of urinary glycosaminoglycans

Se presenta la estandarización de un método para la determinación cuantitativa de glicosaminoglicanos (GAGs) urinarios, empleando una combinación de los métodos descriptos por Di Ferrante y Bitter y Muir, con algunas modificaciones que debieron ser introducidas para adecuarlo a nuestras condiciones experimentales. La determinación se basa en la precipitación de los GAGs por acción de bromuro de cetiltrimetilamonio, seguida de la hidrólisis del polímero y la posterior reacción colorimétrica con carbazol de los ácidos hexurónicos liberados. Se describen, detalladamente, los estudios de estandarización: determinación de la precisión de las distintas etapas del método, linealidad y carta de control de las pendientes de las curvas de calibración, ensayos de recuperación, investigación de interferencias y variaciones en las condiciones de trabajo. Esta metodología puede servir de base para establecer protocolos de control de cualquier procedimiento analítico