Mirta Diez

Accurate real-time PCR strategy for monitoring bloodstream parasitic loads in chagas disease patients.

Background This report describes a real-time PCR (Q-PCR) strategy to quantify Trypanosoma cruzi (T. cruzi) DNA in peripheral blood samples from Chagas disease patients targeted to conserved motifs within the repetitive satellite sequence. Methodology/Principal Findings The Q-PCR has a detection limit of 0.1 and 0.01 parasites/mL, with a dynamic range of 106 and 107 for Silvio X10 cl1 (T. cruzi I) and Cl Brener stocks (T. cruzi IIe), respectively, an efficiency of 99%, and a coefficient of determination (R 2) of 0.998. In order to express accurately the parasitic loads: (1) we adapted a commercial kit based on silica-membrane technology to enable efficient processing of Guanidine Hydrochloride-EDTA treated blood samples and minimize PCR inhibition; (2) results were normalized incorporating a linearized plasmid as an internal standard of the whole procedure; and (3) a correction factor according to the representativity of satellite sequences in each parasite lineage group was determined using a modified real-time PCR protocol (Lg-PCR). The Q-PCR strategy was applied (1) to estimate basal parasite loads in 43 pediatric Chagas disease patients, (2) to follow-up 38 of them receiving treatment with benznidazole, and (3) to monitor three chronic Chagas heart disease patients who underwent heart-transplantation and displayed events of clinical reactivation due to immunosupression. Conclusion/Significance All together, the high analytical sensitivity of the Q-PCR strategy, the low levels of intra- and inter-assay variations, as well as the accuracy provided by the Lg-PCR based correction factor support this methodology as a key laboratory tool for monitoring clinical reactivation and etiological treatment outcome in Chagas disease patients.

Molecular identification of Trypanosoma cruzi discrete typing units in end-stage chronic Chagas heart disease and reactivation after heart transplantation.

BACKGROUND One hundred years after the discovery of Chagas disease, it remains a major neglected tropical disease. Chronic Chagas heart disease (cChHD) is the most severe manifestation. Heart transplantation is the proper treatment for end-stage heart failure, although reactivation of disease may result after receipt of immunosuppressive therapy. T. cruzi strains cluster into 6 discrete typing units (DTUs; I-VI) associated with different geographical distribution, transmission cycles and varying disease symptoms. In the southern cone of South America, T. cruzi II, V, and VI populations appear to be associated with Chagas disease and T. cruzi I with sylvatic cycles. METHODS Molecular characterization of DTUs, T. cruzi I genotypes (on the basis of spliced-leader gene polymorphisms), and minicircle signatures was conducted using cardiac explant specimens and blood samples obtained from a cohort of 16 Argentinean patients with cChHD who underwent heart transplantation and from lesion samples obtained from 6 of these patients who presented with clinical reactivation of Chagas disease. RESULTS Parasite persistence was associated with myocarditis progression, revealing T. cruzi I (genotype Id) in 3 explant samples and T. cruzi II, V, or VI in 5 explant samples. Post-heart transplantation follow-up examination of bloodstream DTUs identified T. cruzi I in 5 patients (genotypes Ia or Id) and T. cruzi II, V, or VI in 7 patients. T. cruzi I, V, and VI were detected in skin chagoma specimens, and T. cruzi V and VI were detected in samples obtained from patients with myocarditis reactivations. Multiple DTUs or genotypes at diverse body sites and polymorphic minicircle signatures at different cardiac regions revealed parasite histotropism. T. cruzi I infections clustered in northern Argentina (latitude, 23 degrees S-27 degrees S), whereas T. cruzi II, V, or VI DTUs were more ubiquitous. CONCLUSIONS Multiple DTUs coexist in patients with Chagas disease. The frequent finding of T. cruzi I associated with cardiac damage was astounding, revealing its pathogenic role in cChHD at the southern cone.

Usefulness of PCR Strategies For Early Diagnosis of Chagas' Disease Reactivation and Treatment Follow-Up in Heart Transplantation

Heart transplantation (HTx) is a useful therapy for end‐stage Chagaś cardiomyopathy; however, Chagas reactivation remains a mayor complication. Parasitological methods offer poor diagnostic sensitivity, and use of more sensitive tools such as the Polymerase chain reaction (PCR) is usually necessary. In the present study, reactivation incidence and PCR usefulness for early reactivation diagnosis, as well as for treatment response evaluation during follow‐up, were analyzed using Strout parasite detection test, in 10 of 222 consecutive HTx patients suffering Chagas cardiomyopathy. PCR strategies targeted to minicircle sequences (kDNA, detection limit 1 parasite/ 10 mL blood) and miniexon genes (SL‐DNA, 200 parasite/10 mL) were performed to compare parasite burdens between samples. No patients received prophylactic antiprotozoal therapy (benznidazole). Five patients (50%) exhibited clinical reactivation within a mean period of 71.6 days; positive Strout results were observed in most cases presenting clinical manifestations. kDNA‐PCR was positive 38–85 days before reactivation, whereas SLDNA‐PCR became positive only 7–21 days later, revealing post‐HTx parasitic load enhancement present prior to clinical reactivation development. Reactivations were successfully treated with benznidazole and generated negative PCR results. Results observed in this study indicate the value of PCR testing for an early diagnosis of Chagas reactivation as well as for monitoring treatment efficacy.

Trypanosoma cruzi Discrete Typing Units in Chagas disease patients from endemic and non-endemic regions of Argentina

Genetic diversity of Trypanosoma cruzi may play a role in pathogenesis of Chagas disease forms. Natural populations are classified into 6 Discrete Typing Units (DTUs) Tc I-VI with taxonomical status. This study aimed to identify T. cruzi DTUs in bloodstream and tissue samples of Argentinean patients with Chagas disease. PCR-based strategies allowed DTU identification in 256 clinical samples from 239 Argentinean patients. Tc V prevailed in blood from both asymptomatic and symptomatic cases and Tc I was more frequent in bloodstream, cardiac tissues and chagoma samples from immunosuppressed patients. Tc II and VI were identified in a minority of cases, while Tc III and Tc IV were not detected in the studied population. Interestingly, Tc I and Tc II/VI sequences were amplified from the same skin biopsy slice from a kidney transplant patient suffering Chagas disease reactivation. Further data also revealed the occurrence of mixed DTU populations in the human chronic infection. In conclusion, our findings provide evidence of the complexity of the dynamics of T. cruzi diversity in the natural history of human Chagas disease and allege the pathogenic role of DTUs I, II, V and VI in the studied population.

Cardiomyocyte hypertrophy, oncosis, and autophagic vacuolization predict mortality in idiopathic dilated cardiomyopathy with advanced heart failure.

OBJECTIVES The aim of this study was to identify the remodeling parameters cardiomyocyte (CM) damage or death, hypertrophy, and fibrosis that may be linked to outcomes in patients with advanced heart failure (HF) in an effort to understand the pathogenic mechanisms of HF that may support newer therapeutic modalities. BACKGROUND There are controversial results on the influence of fibrosis, CM hypertrophy, and apoptosis on outcomes in patients with HF; other modalities of cell damage have been poorly investigated. METHODS In endomyocardial biopsy specimens from 100 patients with idiopathic dilated cardiomyopathy and advanced HF, CM diameter and the extent of fibrosis were determined by morphometry. The proportion of CMs with evidence of apoptosis, autophagic vacuolization (AuV), and oncosis was investigated by immunohistochemical methods and by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling. Those parameters were correlated with mortality in 3 years of follow-up by univariate analysis and with multivariate models incorporating the clinical variables more relevant to the prediction of outcomes. RESULTS CM AuV occurred in 28 patients (0.013 ± 0.012%) and oncosis in 41 (0.109 ± 0.139%). Nineteen patients showed both markers. Apoptotic CM nuclei were observed in 3 patients. In univariate analysis, CM diameter and AuV, either alone or associated with oncosis, were predictors of mortality. In multivariate analysis, CM diameter (hazard ratio: 1.37; 95% confidence interval: 1.12 to 1.68; p = 0.002) and simultaneous presence in the same endomyocardial biopsy specimen of AuV and oncosis (hazard ratio: 2.82; 95% confidence interval: 1.12 to 7.13; p = 0.028) were independent predictors of mortality. CONCLUSIONS CM hypertrophy and AuV, especially in association with oncosis, are predictors of outcome in patients with idiopathic dilated cardiomyopathy and severe HF.

Coronary Microcirculation Remodeling in Patients with Idiopathic Dilated Cardiomyopathy

Background: In patients with idiopathic dilated cardiomyopathy (IDCM), the myocardial blood flow is markedly depressed. The presence of alterations in the number and length of the coronary microcirculation has not been explored. Methods: In explanted hearts of 6 patients with IDCM and in 6 normal control hearts, the arteriolar length density and capillary numerical density were determined in sections stained with orcein (vessels 50–200 µm in diameter), for smooth muscle actin (vessels 6–50 µm in diameter) and CD34 (capillaries). Results: No difference with normal hearts was observed in capillary numerical density and in length density of vessels above 50 µm in diameter. In IDCM, more than 50% of arterioles below 50 µm in diameter displayed an incomplete smooth muscle wall, and length density, especially for arterioles between 6 and 20 µm in diameter, was significantly lower (42.84 ± 8.51 mm/mm3) than in controls (75.34 ± 3.05 mm/mm3, p = 0.001). Conclusions: In IDCM, arterioles below 50 µm in diameter display an incomplete smooth muscle wall and a significant decrease in length density. These observations provide an anatomical basis for a decreased coronary flow reserve in IDCM.

High-sensitivity troponin is associated with high risk clinical profile and outcome in acute heart failure.

BACKGROUND The aim of the study was to evaluate the value of high-sensitivity cardiac troponin (hs-cTn) for identifying high-risk patients. METHODS AND RESULTS One hundred and eighty-seven patients admitted with acute heart failure (HF) (without myocardial infarction) were consecutively included; hs-cTn was measured at admission; the relation between elevated hs-cTn and the clinical outcome during hospitalization and at 90 days was analyzed; 93% (n = 174) had hs-cTn above the maximal normal value (14 ng/L); median hs-cTn was 42 ng/L (IQR 24-81). Patients with ejection fraction (EF) ≤ 45% had higher hs-cTn values (p = 0.0004). Patients with low cardiac output syndrome (LCOS) or shock had higher troponin levels compared with those with less severe clinical presentations (p = 0.004). Patients who required inotropic presented higher troponin values (p = 0.002), troponin values were also higher in those requiring complex therapies (intra-aortic balloon pump, mechanical ventilation or hemodialysis, p = 0.002). At 90-day follow-up, 28 (15.5%) patients died and 27 rehospitalizations occurred (55 events). The risk of events was greater in patients with hs-cTn > 42 ng/L (0.021), low blood pressure at admission (p = 0.002), LCOS or shock (p < 0.0001), EF ≤ 45% (p = 0.005) and inotropic use (p < 0.0001). In multivariate analysis, only inotropic agents requirements was associated independently with a high risk of death or rehospitalizations at 90 days (p = 0.007). CONCLUSIONS Elevation of hs-cTn is a finding almost constant in patients with decompensated HF. In subjects with higher troponin levels ventricular dysfunction is frequent. The use of hs-cTn for risk stratification at admission helps to identify populations with poor outcome during hospitalization and increased risk of death or rehospitalizations during follow-up who will require rapid implementation of aggressive treatment.

Heart transplantation in rapidly progressive end-stage heart failure associated with celiac disease.

Celiac disease is characterised by chronic immune-mediated malabsorption in genetically susceptible individuals induced by gluten proteins present in wheat, barley and rye. It occurs in adults and children at rates approaching 1% of the population. Cardiomyopathy associated with celiac disease is infrequent. The authors present here a first case of a severe progressive dilated cardiomyopathy that required heart transplantation in young woman with celiac disease.

Uso de recursos y costos de hospitalizaciones por insufi ciencia card í aca: un estudio retrospective multic é ntrico en Argentina

OBJECTIVES Heart failure has a great impact on health budget, mainly due to the cost of hospitalizations. Our aim was to describe health resource use and costs of heart failure admissions in three important institutions in Argentina. METHODS Multi-center retrospective cohort study, with descriptive and analytical analysis by subgroups of ejection fraction, blood pressure and renal function at admission. Generalized linear models were used to assess the association of independent variables to main outcomes. RESULTS We included 301 subjects; age 75.3±11.8 years; 37% women; 57% with depressed ejection fraction; 46% of coronary etiology. Blood pressure at admission was 129.8±29.7 mmHg; renal function 57.9±26.2 ml/min/1.73 m2. Overall mortality was 7%. Average length of stay was 7.82±7.06 days (median 5.69), and was significantly longer in patients with renal impairment (8.9 vs. 8.18; p=0.03) and shorter in those with high initial blood pressure (6.08±4.03; p=0.009). Mean cost per patient was AR

Adding ivabradine may reduce elevated heart rate in acute patients when β blockers are ineffective.

68,861±96,066 (US