Functional Autoreactive Anti-ß2 Adrenergic Antibodies May Contribute to Insulin Resistance Profile in Patients with Chronic Chagas Disease.

Potential activation of ß2 adrenergic receptors (ß2AR) by specific autoreactive antibodies (Abs) that arise during the host reaction to Trypanosoma cruzi, could contribute to the elevated prevalence of metabolic disturbances described in patients with chronic Chagas disease (CCD). This study aimed to determine the prevalence of anti-ß2AR Abs in patients with CCD, as well as the correlation of these Abs with the presence of glucose and lipid metabolism disturbances, in order to explore their association with an insulin resistance profile. Additionally, we tested the functional effects of anti-ß2AR Abs employing an in vitro bioassay with neuroendocrine cells expressing ß2AR. A clinical and metabolic evaluation including an OGTT was performed in 80 CCD patients and 40 controls. Anti-ß2AR Abs were measured by an in-house-developed ELISA, and the ß2 adrenergic activity of affinity-purified IgG fractions from patient' sera were assayed in CRE-Luc and POMCLuc transfected AtT-20 cells. A higher proportion of dysglycemia (72.5% vs. 37.5%; p = 0.001) was observed in the CCD group, accompanied by increased HOMA2-IR (p = 0.019), especially in subjects with Abs (+). Anti-ß2AR Abs reactivity (7.01 (2.39-20.5); p = 0.0004) and age >50 years (3.83 (1.30-11.25); p = 0.014) resulted as relevant for IR prediction (AUC: 0.786). Concordantly, Abs (+) CCD patients showed elevated metabolic risk scores and an increased prevalence of atherogenic dyslipidemia (p = 0.040), as compared to Abs (-) patients and controls. On functional bioassays, Abs exerted specific and dose-dependent ß2-agonist effects. Our findings suggest that anti-ß2AR Abs may induce the activation of ß2AR in other tissues besides the heart; furthermore, we show that in patients with CCD these Abs are associated with an insulin resistance profile and atherogenic dyslipidemia, providing biological plausibility to the hypothesis that adrenergic activation by anti-ß2AR Abs could contribute to the pathogenesis of metabolic disturbances described in CCD patients, increasing their cardiovascular risk.

Moderate Exercise Prevents Functional Remodeling of the Anterior Pituitary Gland in Diet-Induced Insulin Resistance in Rats: Role of Oxidative Stress and Autophagy.

A sustained elevation of glucocorticoid production, associated with the establishment of insulin resistance (IR) could add to the deleterious effects of the IR state. The aim of this study is to analyze the consequences of long-term feeding with a sucrose-rich diet (SRD) on Pomc/ACTH production, define the underlying cellular processes, and determine the effects of moderate exercise (ME) on these parameters. Animals fed a standard chow with or without 30% sucrose in the drinking water were subjected to ME. Circulating hormone levels were determined, and pituitary tissues were processed and analyzed by immunobloting and quantitative real-time PCR. Parameters of oxidative stress (OxS), endoplasmic reticulum stress, and autophagy were also determined. Rats fed SRD developed a decrease in pituitary Pomc/ACTH expression levels, increased expression of antioxidant enzymes, and induction of endoplasmic reticulum stress and autophagy. ME prevented pituitary dysfunction as well as induction of antioxidant enzymes and autophagy. Reporter assays were performed in AtT-20 corticotroph cells incubated in the presence of palmitic acid. Pomc transcription was inhibited by palmitic acid-dependent induction of OxS and autophagy, as judged by the effect of activators and inhibitors of both processes. Long-term feeding with SRD triggers the generation of OxS and autophagy in the pituitary gland, which could lead to a decline in Pomc/ACTH/glucocorticoid production. These effects could be attributed to an increase in fatty acids availability to the pituitary gland. ME was able to prevent these alterations, suggesting additional beneficial effects of ME as a therapeutic strategy in the management of IR.

Single and multiple mutations in the human cytomegalovirus UL97 gene and their relationship to the enzymatic activity of UL97 kinase for ganciclovir phosphorylation.

In this study we determined that the double mutant M460V/D605E in the UL97 gene of an HCMV isolate from an immunocompromised patient (MMT isolate) is related to resistance to ganciclovir (GCV) therapy. Our results suggest that the aspartic acid-to-glutamic acid substitution at codon 605 may be associated with a natural polymorphism of the UL97 gene, and not with positive selection pressure exerted by the antiviral drug. We also determined that GCV resistance due to the M460V mutation in the HCMV UL97 gene is not offset by a second mutation (D605E) at codon 605. Furthermore, we showed that when the two mutations related to GCV resistance were simultaneously detected in the same HCMV construct, virus-drug resistance might be enhanced in comparison to that of the single mutants studied separately. To our knowledge for the first time, seven of 12 amino acid changes (F102L, D118V, M330T, T400A, R507P and C511R and I533V) in the UL97 gene of an isolate are herein reported.

Phenotypic and genotypic characterization of Aspergillus lentulus and Aspergillus fumigatus isolates in a patient with probable invasive aspergillosis.

Characteristic morphological and phylogenetic analyses demonstrated the presence of Aspergillus fumigatus and Aspergillus lentulus as the aetiological agents in a case of probable invasive aspergillosis (IA). This is believed to be the first report of an A. lentulus strain isolated from a patient with probable IA in Argentina.

Cytomegalovirus UL97 mutations associated with ganciclovir resistance in immunocompromised patients from Argentina.

BACKGROUND: Prolonged therapy with ganciclovir (GCV) can result in the development of GCV-resistant strains due to mutations in the viral phosphotransferase (UL97 gene) and/or in the viral DNA polymerase (UL54 gene). OBJECTIVES: The purpose of this study was to detect by molecular methods the most prevalent UL97 mutants which confer ganciclovir-resistance in immunocompromised populations. STUDY DESIGN: Patients from two populations were selected: (a) renal transplant patients with active cytomegalovirus (CMV) infection and more than one cycle of GCV; (b) HIV-infected patients with retinitis due to CMV, who were under GCV induction, maintenance therapy or withdrawal. Patients were followed up by pp65 antigenemia and by viral isolation from blood or/and urine samples. Two fragments (133 and 255pb) of the UL97 gene were amplified by polymerase chain reaction (PCR) from CMV isolates. RESULTS: Nine from 12 isolates obtained were sequenced, three from two renal transplant patients and six from five HIV-infected patients. A UL97 mutation, known to confer GCV resistance, was found in two isolates from a renal transplant patient. A methionine to valine mutation at codon 460 (M460V) was detected. These isolates exhibited another mutation at codon 605, whose amino acid changed from aspartic acid (D) to glutamic acid (E). These findings were observed after treatment with IV-GCV/ O-GCV/ IV-GCV for 151 days. The 605 mutation was also detected in leukocytes from the same patient previous to the beginning of the treatment with GCV. CONCLUSIONS: Although a known resistant mutation appeared in a renal transplant patient, it was not associated with CMV disease. We suggest that the D605E mutation could "partially or totally compensate" for the effect of GCV resistance conferred by the 460 mutation. Further studies should be performed to confirm this hypothesis.