Prospective study of ventricular function and myocardial deformation related to survival in acute Chagas disease: an experimental animal model

Chagas disease (CD) has been changing from an endemic Latino-American disease to a condition found outside endemic regions, due to migratory movements. Although often subclinical, its acute phase can be lethal. This study aimed to assess survival during the acute phase of CD and its relationship with ventricular function in an experimental model. To this end, 30 Syrian hamsters were inoculated with Trypanosoma cruzi (IG) and other 15 animals received saline solution (CG). Groups were monitored daily and submitted to echocardiography in two moments: before the challenge and 15 days post-infection. Left ventricular ejection fraction (LVEF) and global longitudinal myocardial strain (GLS) of the LV were measured. The IG was divided into groups of animals with and without clinical signs of disease. ANOVA for mixed models was used to compare ventricular function parameters. Survival analysis was studied using Kaplan-Meier curves and the log-rank test. The follow-up lasted 60 days. LVEF in IG was reduced through time (53.80 to 43.55%) compared to CG (57.86 to 59.73%) (p=0.002). There was also a reduction of GLS (−18.97% to −12.44%) in the IG compared to CG (p=0.012). Twelve animals from IG died compared to one animal from CG. Eleven out of the 12 animals from the IG group died before presenting with clinical signs of infection. Survival was reduced in the IG compared to CG over time (p=0.02). The reduced survival during the acute phase of this experimental model of Chagas disease was related to the significant reduction of LV function. The mortality rate in the IG was higher in the group presenting with clinical signs of infection

Effect of prolonged use of pentoxifylline in experimental model of chronic Chagas cardiomyopathy in hamsters

A doença de Chagas permanece como importante problema de saúde pública na América Latina, sendo atualmente uma doença emergente em países não endêmicos. É uma das principais causas de insuficiência cardíaca e morte súbita. A ocorrência de distúrbios microvasculares é comum na cardiomiopatia crônica da doença de Chagas (CCC), podendo ocorrer secundariamente à inflamação miocárdica, e está relacionada ao desenvolvimento da disfunção ventricular esquerda. Assim, levanta-se a hipótese de que a terapia com droga imunomoduladora, capaz de atenuar o processo inflamatório miocárdico, possa reduzir as alterações de perfusão e impedir a progressão da disfunção miocárdica na CCC. Nesse contexto, o presente estudo teve por objetivo avaliar os efeitos do uso prolongado da pentoxifilina (PTX) sobre as alterações perfusionais miocárdicas e atividade inflamatória cardíaca e suas correlações com a evolução da disfunção sistólica ventricular esquerda, mediante emprego de métodos de imagem de alta resolução in vivo em modelo experimental de CCC em hamsters sírios. Inicialmente, os animais foram divididos nos seguintes grupos: controle + salina (CTR+SLN, n=9), controle + pentoxifilina (CTR+PTX, n=11), chagas + salina (CH+SLN, n=12) e chagas + pentoxifilina (CH+PTX, n=12). Na janela temporal de 6 meses pós infecção pelo T. cruzi (condição basal), os animais foram submetidos aos seguintes métodos de imagem in vivo: cintilografia de perfusão miocárdica com Sestamibi-Tc-99m (Mini-SPECT) e ecocardiografia transtorácica. Posteriormente, os animais foram tratados por 60 dias com PTX (20 mg/Kg/dia, ip) ou salina e, em seguida, foram reavaliados com os mesmos métodos de imagem. Ao final do estudo, o tecido miocárdico foi processado para análise histológica quantitativa para extensão de fibrose e do infiltrado inflamatório. Na condição basal, não evidenciamos diferença significativa entre os grupos estudados nos parâmetros ecocardiográficos (FEVE, DdVE e escore MPS) e de perfusão miocárdica. Após o tratamento, foi encontrado aumento significativo das áreas de defeitos de perfusionais (p=0,004) nos animais dos grupos CTR+PTX, de 0,0% (0,0-1,4) para 5,1% (0,0-18,0), e CH+SLN, de 0,0% (0,0-5,1) para 5,8% (0,0-30,3), enquanto que o grupo CH+PTX: 2,0% (0,0-7,0) apresentou valores semelhantes ao grupo CTR+SLN: 0,0 (,0-0,0). Foi observado redução, apesar de não significativa estatisticamente, dos valores de fração de ejeção do ventrículo esquerdo (FEVE) nos grupos CTR+PTX, de 54,0% (42,0-58,0) para 43,0% (33,0-56,0), CH+SLN, de 47,5% (26,0-59,0) para 38,0% (14,0-59,0) e CH+PTX, de 56,5% (37,0-59,0) para 42,5% (26,0-58,0), p>0,05 e aumento do diâmetro diastólico (DdVE) nos grupos CTR+PTX, de 7,7mm (7,1-8,5) para 8,1mm (7,5-9,4), CH+SLN, de 7,8mm (6,7-8,9) para 8,1mm (6,9-10,3) e CH+PTX, de 7,3 mm (6,3-8,1) para 7,9mm (6,9-9,3), p>0,05 após o tratamento. Na análise histológica, observou-se maior número de núcleos de células inflamatórias no grupo CH+SLN, 655,0 cel/mm² (425,0-779,0) e CH+PTX, 388,0 cel/mm² (248,0-582,0), quando comparado ao grupo CTR+SLN, 204,0 cel/mm² (148,0-225,0) e CTR+PTX, 220,5 cel/mm² (181,0-268,0), p 0.05, and increase of diastolic diameter in the CTR+PTX groups, 7.7 mm (7.1-8.5 mm) to 8.1 mm (7.5-9.4), CH+SLN, from 7.8 mm (6.7-8.9) to 8.1 mm (6.9-10.3) and CH+PTX, from 7.3 mm (6.3-8.1) to 7.9 mm (6.9-9.3), p> 0.05 after treatment. Quantitative histological analysis revealed a larger number of nuclei of mononuclear inflammatory cells in the CH+SLN, 655.0 cel/mm² (425.0-779.0) and CH+PTX groups, 388.0 cel/mm² (248.0-582.0) when compared to the CTR+SLN group, 204.0 cel/mm² (148.0-225.0) and CTR+PTX groups, 220.5 (181.0-268.0). A higher number of inflammatory cells was also found in the CH + SLN group when compared to the CH + PTX group. The percentage of fibrosis was similar among the groups studied. Conclusions: The prolonged use of PTX in CCC animals was associated with reduced progression of myocardial perfusion defects evaluated in vivo. However, the reduction of myocardial perfusion defects did not prevent the progression of left ventricular systolic dysfunction or reduced intensity of inflammatory tissue lesions in this experimental model. Therefore, our results suggest that PTX may have selectively acted on coronary microvascular dysfunction, with no significant effect on reducing inflammatory tissue lesions

Study of the effect of a vasodilating agent of the coronary microcirculation on myocardial perfusion disorders and left ventricular dysfunction in a hamster model of chronic chagasic cardiomyopathy

A doença de Chagas ainda permanece como um importante problema de saúde em regiões endêmicas na América Latina, onde se estima 8 a 10 milhões de infectados. A isquemia microvascular é frequente na cardiomiopatia chagásica crônica (CCC) e pode estar envolvida nos processos fisiopatogênicos que levam à disfunção sistólica ventricular esquerda (DSVE). Lança-se a hipótese que a redução da isquemia microvascular possa atenuar a progressão da DSVE na CCC. Desta forma, nosso objetivo foi avaliar os efeitos do uso prolongado do dipiridamol (DIPI), um agente vasodilatador da microcirculação coronária, sobre a perfusão miocárdica e sobre a função sistólica do ventrículo esquerdo mediante emprego de métodos de imagem in vivo. Foram utilizados 60 hamsters fêmeas adultas divididas em: animais infectados com T. cruzi e tratados com DIPI (Chagas + DIPI, n=15); infectados tratados com placebo (Chagas + Placebo, n=15); animais não infectados, tratados com DIPI (Controle + DIPI, n=15) e tratados com placebo (Controle + placebo, n=15). Após 6 meses de infecção (condição basal), os animais foram submetidos a ecocardiograma e a cintilografia de perfusão miocárdica por SPECT com Sestamibi-Tc99m. Em seguida, foram tratados com injeções intraperitoneais de DIPI (4mg/Kg) duas vezes ao dia ou igual volume de salina, durante 30 dias. Após o tratamento, os animais foram reavaliados com os mesmos métodos de imagem e a seguir sofreram eutanásia e o tecido cardíaco foi preparado para análise histológica quantitativa para extensão de fibrose (coloração de picrosírius vermelho) e do infiltrado inflamatório (coloração de hematoxilinaeosina). Na condição basal os animais do grupo Chagas + placebo e Chagas + DIPI apresentaram maior área de defeito de perfusão (19,2 ± 5,4% e 20,9 ± 4,2%, respectivamente, quando comparados aos grupos controle + placebo e controle + DIPI (3,8 ± 0,7% e 3,6 ± 0,9%, respectivamente), p=0<0,05, mas valores semelhantes de fração de ejeção do ventrículo esquerdo (FEVE), p=0,3, e de diâmetro diastólico do ventrículo esquerdo (DdVE,), p=0,2. Após o tratamento, observou-se redução significativa dos defeitos de perfusão somente no grupo Chagas + DIPI (p=0,02). Quando comparados os valores basais e após tratamento, os animais dos grupos Chagas + DIPI e Chagas + placebo apresentaram redução da FEVE (65,3 ± 2,5% para 53,6 ± 1,9% e 69,3 ± 1,4% para 54,4 ± 2,5%, respectivamente (p<0,001), e aumento do DdVE de 0,68 ± 0,5 cm para 0,76 ±0,17 cm e 0,64 ± 0,01 cm para 0,71 ± 0,23 cm, respectivamente (p<0,002). Na análise histológica quantitativa, observou-se maior número de núcleos de células inflamatórias mononucleares nos grupos Chagas + DIPI (998,1 ± 116,0 cel/mm²) e Chagas + Placebo (1191,4 ± 133,2 cel/mm²) quando comparados aos grupos Controle + DIPI (396,5 ± 28,3 cel/mm²) e Controle + Placebo (257,1 ± 21,6 cel/mm²), p=0,05. A porcentagem de fibrose foi maior nos grupos Chagas + DIPI (4,7 ± 0,4%) e Chagas + Placebo (5,4 ± 0,2%) quando comparados com o grupo controle + Placebo (3,2 ± 0,3%). Não houve diferença entre os grupos Chagas + DIPI e Chagas + Placebo em ambas as variáveis da histologia. Conclusões: O uso prolongado de DIPI em animais com CCC associou-se à significativa redução dos defeitos de perfusão miocárdica avaliados in vivo. Contudo, a resolução da isquemia microvascular mediante emprego de DIPI não impediu a progressão da disfunção ventricular esquerda. Esses resultados sugerem que a isquemia microvascular não seja um mecanismo lesivo miocárdico central no complexo fisiopatogênico neste modelo de CCC. É plausível supor que a isquemia microvascular seja um marcador da presença de processo lesivo subjacente, provavelmente de natureza inflamatória.Chagas disease continues to be an important public health problem in endemic regions of Latin America, where 8 to 10 million infected people are estimated to live. Microvascular ischemia is frequent in chronic chagasic cardiomyopathy (CCC) and may be involved in the physiopathogenic processes that lead to left ventricular systolic dysfunction (LVSD). The hypothesis is raised that reduction of microvascular ischemia may attenuate the progression of LVSD in CCC. Thus, our objective was to assess the effects of prolonged use of dipyridamole (DIPY), a coronary microvascular dilator agent, on myocardial perfusion and on left ventricular systolic function using imaging methods in vivo. A total of 60 adult female hamsters were divided into the following groups: T. cruzi-infected animals treated with DIPY (Chagas + DIPY, n=15); infected animals treated with placebo (Chagas + Placebo, n=15); uninfected animals treated with DIPY (Control + DIPY, n=15) and treated with placebo (Control + placebo, n=15). After 6 months of infection (baseline condition), the animals were submitted to an echocardiogram and to rest myocardial perfusion scintigraphy by SPECT with SestamibiTc99m. Next, the animals were treated with intraperitoneal injections of DIPY (4 mg/kg) twice a day or with an equal volume of saline for 30 days. After treatment, the animals were reevaluated by the same imaging methods and euthanized. Cardiac tissue was prepared for quantitative histological analysis of the extent of fibrosis (picrosirius red staining) and of the inflammatory infiltrate (hematoxylin-eosin staining). At baseline, the group Chagas + placebo and Chagas + DIPY showed a larger area of perfusion defect (19.2 ± 5.4% and 20.9 ± 4.2%, respectively) compared to control + placebo and control + DIPY (3.8 ± 0.7% e 3.6 ± 0.9%, respectively), p<0.05, but similar left ventricular ejection fraction (LVEF), p=0.3, and left ventricular diastolic diameter (LVdD), p=0.2. After treatment, a significant reduction of perfusion defects was observed only in the Chagas + DIPY group (p=0.02). When the values after treatment were compared to baseline values, Chagas + DIPY and Chagas + placebo animals showed a reduction of LVEF (from 65.3 ± 2.5% to 53.6 ± 1.9% and from 69.3 ± 1.4% to 54.4 ± 2.%5, respectively), p<0.001, and an increase of LVdD from 0.68 ± 0,15 cm to 0.76 ± 0.17 cm and from 0.64 ± 0.01 cm to 0.70 ± 0,02 cm, respectively, p<0.002. Quantitative histological analysis revealed a larger number of nuclei of mononuclear inflammatory cells in the Chagas + DIPY (998.1 ± 116.0 cel/mm²) and Chagas + Placebo (1191.4 ± 133.2 cells/mm²) groups compared to the Control + DIPY (396.5 ± 28.3 cells/mm²) and Control + Placebo (257.1 ± 21.6 cells/mm²) groups, p=0.05. The percentage of fibrosis was higher in the Chagas + DIPY (4.7 ± 0.4%) and Chagas + Placebo (5.4 ± 0.2%) groups compared to the Control + Placebo group (3.2 ± 0.3%). There was no difference between the Chagas + DIPY and Chagas + Placebo groups regarding the two histological variables. Conclusions: The prolonged use of DIPY in animals with CCC was associated with a significant reduction of myocardial perfusion defects assessed in vivo. However, the resolution of microvascular ischemia with the use of DIPY did not prevent the progression of left ventricular dysfunction. These results suggest that microvascular ischemia may not be a central myocardial injury mechanism in the physiopathogenic complex of this CCC model. It is plausible to assume that microvascular ischemia may be a marker of the presence of an underlying injury process probably of an inflammatory nature

Empagliflozin in Patients with Chronic Kidney Disease

Background The effects of empagliflozin in patients with chronic kidney disease who are at risk for disease progression are not well understood. The EMPA-KIDNEY trial was designed to assess the effects of treatment with empagliflozin in a broad range of such patients. Methods We enrolled patients with chronic kidney disease who had an estimated glomerular filtration rate (eGFR) of at least 20 but less than 45 ml per minute per 1.73 m(2) of body-surface area, or who had an eGFR of at least 45 but less than 90 ml per minute per 1.73 m(2) with a urinary albumin-to-creatinine ratio (with albumin measured in milligrams and creatinine measured in grams) of at least 200. Patients were randomly assigned to receive empagliflozin (10 mg once daily) or matching placebo. The primary outcome was a composite of progression of kidney disease (defined as end-stage kidney disease, a sustained decrease in eGFR to &lt; 10 ml per minute per 1.73 m(2), a sustained decrease in eGFR of &amp; GE;40% from baseline, or death from renal causes) or death from cardiovascular causes. Results A total of 6609 patients underwent randomization. During a median of 2.0 years of follow-up, progression of kidney disease or death from cardiovascular causes occurred in 432 of 3304 patients (13.1%) in the empagliflozin group and in 558 of 3305 patients (16.9%) in the placebo group (hazard ratio, 0.72; 95% confidence interval [CI], 0.64 to 0.82; P &lt; 0.001). Results were consistent among patients with or without diabetes and across subgroups defined according to eGFR ranges. The rate of hospitalization from any cause was lower in the empagliflozin group than in the placebo group (hazard ratio, 0.86; 95% CI, 0.78 to 0.95; P=0.003), but there were no significant between-group differences with respect to the composite outcome of hospitalization for heart failure or death from cardiovascular causes (which occurred in 4.0% in the empagliflozin group and 4.6% in the placebo group) or death from any cause (in 4.5% and 5.1%, respectively). The rates of serious adverse events were similar in the two groups. Conclusions Among a wide range of patients with chronic kidney disease who were at risk for disease progression, empagliflozin therapy led to a lower risk of progression of kidney disease or death from cardiovascular causes than placebo