Telomere length and telomerase activity are important factors in the pathobiology of human diseases. Age-related diseases and premature aging syndromes are characterized by short telomeres, which can compromise cell viability, whereas tumour cells can prevent telomere loss by aberrantly upregulating telomerase. The zebrafish (Danio rerio) offers multiple experimental manipulation advantages over other vertebrate models and, therefore, it has been recently considered as a potential model for aging, cancer, and regeneration studies. However, it has only partially been exploited to shed light on these fundamental biological processes. The aim of this study was, therefore, to investigate telomere length and telomerase expression and activity in different strains of zebrafish obtained from different stock centres to determine whether they undergo any changes during aging and regeneration. We found that although both telomerase expression and telomere length increased from embryo to adulthood stages, they drastically declined in aged fish despite telomerase activity was detected in different tissues of old fish. In addition, we observed a weaker upregulation of telomerase expression in regenerating fins of old fish, which well correlates with their impaired regeneration capacity. Strikingly, telomeres were elongated or maintained during the fin regeneration process at all ages and after repeated amputations, likely to support high cell proliferation rates. We conclude that the expression of telomerase and telomere length are closely related during the entire life cycle of the fish and that these two parameters can be used as biomarkers of aging in zebrafish. Our results also reveal a direct relationship between the expression of telomerase, telomere length and the efficiency of tissue regeneration.

Mucormycosis is an emerging fungal infection caused by Mucorales with an unacceptable high mortality rate. Mucorales is a complex fungal group, including eleven different genera that can infect humans. This heterogeneity is associated with species-specific invasion pathways and responses to the host defense mechanisms. The host innate immune system plays a major role in preventing Mucorales growth and host invasion. In this system, macrophages are the main immune effector cells in controlling these fungi by rapid and efficient phagocytosis of the spores. However, Mucorales have evolved mechanisms to block phagosomal maturation and species-specific mechanisms to either survive as dormant spores inside the macrophage, as Rhizopus species, or geminate and escape, as Mucor species. Classical fungal models of mucormycosis, mostly Rhizopus, have made important contributions to elucidate key aspects of the interaction between Mucorales and macrophages, but they lack robust tools for genetic manipulation. The recent introduction of the genetically tractable Mucor circinelloides as a model of mucormycosis offers the possibility to analyze gene function. This has allowed the identification of regulatory pathways that control the fungal response to phagocytosis, including a non-canonical RNAi pathway (NCRIP) that regulates the expression of most genes regulated by phagocytosis.

We evaluated the effectiveness of treating women of childbearing age with benznidazole to prevent Congenital Chagas disease (CCD), as well as the usefulness of Polymerase Chain Reaction (PCR) as a tool to predict the risk of transmission. Prospective study involving 144 T. cruzi seropositive pregnant women. The parasitological status was studied by PCR in 159 pregnancies, 38 of which involved a historical cohort study of previously treated mothers. 160 children were examined by PCR and serologically studied at 0-6, 9 and 12 months and annually after treatment. PCR was seen to be useful for predicting the risk of congenital transmission: 18.8% of mothers with a positive PCR result transmitted the infection (16 infected children out of 85 pregnancies). No infected infants were detected among 74 pregnancies when PCR was negative [NPV: 100%]. Of the treated mothers, 92.1% had negative PCR results, compared with 32.2% of untreated mothers. No infected infants were detected from previously treated mothers, compared with 13.2% among untreated mothers (p = 0.019; ?2). All infants treated before the first year of life were cured. Treating infected women of childbearing age prevents CCD by reducing the parasitemia. PCR is an useful tool in the CCD diagnostic algorithm.

This prospective study focused on the evaluation of antiparasitic therapy in chronic Chagas’ disease, monitored by PCR. One hundred and eighty-one patients, all seropositive for Trypanosoma cruzi infection, underwent specific chemotherapy with benznidazole. Twelve patients were classified as young (2–19 years), 122 patients were classified as adults (20–39 years) and 47 patients were classified as seniors (≥40 years). In total, 116 (64%) were asymptomatic and 65 (36%) were symptomatic. Patients were monitored for 90, 150 and 420 days after treatment by PCR and serology. Before treatment, 68% had a positive PCR result. PCR positivity was significantly more frequent in patients aged 2–19 years (P = 0.0007) and in short-term immigrants (P = 0.0076). No differences in PCR sensitivity were observed between samples of patients with chronic symptomatic or indeterminate Chagas’ disease. All patients presented an early conversion of PCR results 90 days post-treatment. However, at the end of the follow-up period PCR had become positive in four patients (4 out of 58 patients; 6.9%) who had strictly adhered to the treatment and in one who did not complete the treatment. Only one patient showed an alternating PCR during follow-up. We conclude that PCR is a useful tool for the early detection of parasite susceptibility to benznidazole and for the post-treatment parasitological follow-up of patients with chronic Chagas' disease.

Background. In this longitudinal cohort study we evaluated the congenital transmission of Chagas disease (CD) in a nonendemic area. The aim of this work was to analyze the predictive value of a Trypanosoma cruzi–positive polymerase chain reaction (PCR) result in pregnant women for the diagnosis of vertical transmission and to evaluate the use of PCR as a tool for early detection of infection. Methods. The offspring of 59 seropositive pregnant mothers were followed up. The parasitological status of mothers was studied by PCR in a total of 64 pregnancies; 10 of these women had received treatment before pregnancy. Sixty-five infants (including a pair of twins) were monitored at 0, 6, 9, and 12 months of age by PCR and serology. In cases of congenital transmission, hemoculture and parasite lineage typing were performed. Results. Nine infants had acquired CD congenitally. This represents a transmission rate of 13.8% among seropositive mothers (9 infected newborns of 65 total live births). All infants were infected with T. cruzi discrete typing unit V strain. A statistically significant correlation was found between T. cruzi vertical transmission and a positive PCR result during pregnancy (31%; 9 infected newborns in 29 live births). No infected infants were detected among 10 mothers who were treated before they became pregnant, compared with 16.4% (9 of 55 live births) among untreated mothers. Conclusions. PCR is a useful tool for the detection of congenital CD, and the treatment of infected women of childbearing age seems to be useful for preventing vertical transmission.