Endothelial Function Is Preserved in Chagas' Heart Disease Patients Without Heart Failure

Systemic microvascular endothelial dysfunction is associated with left ventricular ejection fraction reduction in chronic Chagas disease patients

OBJECTIVE

This study compares microvascular reactivity (MR) in chronic Chagas disease (CD) patients with healthy individuals, matched for sex and age. In addition, we evaluated the association between MR and left ventricular ejection fraction (LVEF) in patients.

METHODS

Acetylcholine iontophoresis was performed on the forearm skin, using laser speckle contrast imaging, to evaluate endothelium-dependent vasodilation. Clinical data were obtained from medical records.

RESULTS

Thirty-six patients were compared to 25 healthy individuals (controls). Vasodilation was higher in controls, when compared to patients (p < .0001). There was a significant association between LVEF, stratified into quartiles, and MR (p-value for linear trend = .002). In addition, there was no difference in MR between patients with normal LVEF and the control group. In patients, MR was independent of the presence of arterial hypertension or diabetes.

CONCLUSIONS

We have shown for the first time that the reduction of MR is associated with a decrease of LVEF in a cohort of chronic CD patients. The results were not affected by comorbidities, such as hypertension or diabetes. The evaluation of systemic endothelial function may be useful to tailor therapeutic and preventive approaches, targeted at systolic left ventricular failure associated with chronic CD cardiomyopathy.

[Endothelial function and high-sensitivity C-reactive protein levels in patients with Chagas disease living in a nonendemic area]

INTRODUCTION AND OBJECTIVES

The number of patients with Chagas disease in Spain has increased significantly. Chronic inflammation and endothelial dysfunction have been considered among the physiopathological mechanisms of Chagas heart disease. However, there have been conflicting data from clinical studies. Our purpose was to assess endothelial function and systemic levels of nitric oxide and high-sensitivity C-reactive protein in patients with the indeterminate form and with chronic Chagas cardiomyopathy living in a nonendemic area.

METHODS

Flow-mediated endothelium-dependent vasodilatation and nitroglycerin-mediated vasodilatation were assessed with high-resolution ultrasound of the brachial artery in 98 subjects (32 with the indeterminate form, 22 with chronic Chagas cardiomyopathy and 44 controls). Nitric oxide and high-sensitivity C-reactive protein levels were measured in peripheral venous blood.

RESULTS

Mean age was 37.6 ± 10.2 years and 60% were female. Nitroglycerin-mediated vasodilatation was significantly reduced in chronic Chagas cardiomyopathy compared to controls (median 16.8% vs 22.5%; P=.03). No significant differences were observed in flow-mediated vasodilatation and nitric oxide levels, although a trend towards lower flow-mediated vasodilatation after correction by baseline brachial artery diameter was observed in chronic Chagas cardiomyopathy. Levels of C-reactive protein were significantly higher in patients with the indeterminate form and with Chagas cardiomyopathy compared with controls (P<.05).

CONCLUSIONS

Reduced nitroglycerin-mediated vasodilatation suggesting dysfunction of vascular smooth muscle cells was found in patients with chronic Chagas cardiomyopathy living in a nonendemic area. Higher C-reactive protein levels were observed in the indeterminate form and early stages of chronic Chagas cardiomyopathy, which could be related to the inflammatory response to the infection or early cardiovascular involvement.

Inflammatory and Prothrombotic Activation With Conserved Endothelial Function in Patients With Chronic, Asymptomatic Chagas Disease

Previously, our group showed a prothrombotic state in asymptomatic patients with chronic Chagas disease. The current paper studies the inflammatory status and endothelial function in these patients. Methods: In 40 patients and 40 healthy volunteers, we evaluated prothrombotic state, blood parasitemia (molecular biology: polymerized chain reaction [PCR]-amplification), tissue factor pathway inhibitor antibodies (aTFPI), interleukin 6 (IL-6), and vascular cell adhesion molecule-1 (VCAM-1). Endothelial function was determined by reactive hyperemia (pulse plethysmography). Results: In patients, prothrombin fragment 1 + 2, d-dimer, PAI-1, and fibrinogen were higher. Amplification of 121/122 primers ( Trypanosoma cruzi) was positive in 45% of the patients. Patients presented higher values of aTFPI- immunoglobulin G (IgG; P < .05), aTFPI-IgM ( P < .001), IL-6 ( P = .004), and VCAM-1 ( P = .00001). In both groups, endothelial function was preserved. Conclusions: We found that asymptomatic patients with chronic Chagas disease presented a prothrombotic/inflammatory status. The fact that endothelial function is still preserved suggests that prothrombosis and inflammation are primarily implicated in the beginning of cardiovascular damage.

Trypanosoma cruzi infection induces proliferation of vascular smooth muscle cells

Trypanosoma cruzi infection causes cardiomyopathy and vasculopathy. Previous studies have demonstrated that infection of human umbilical vein endothelial and smooth muscle cells resulted in activation of extracellular signal-regulated kinase (ERK). In the present study, smooth muscle cells were infected with trypomastigotes, and immunoblot analysis revealed an increase in the expression of cyclin D1 and proliferating cell nuclear antigen (PCNA), important mediators of smooth muscle cell proliferation. Interestingly, after infection, the expression of caveolin-1 was reduced in both human umbilical vein endothelial cells and smooth muscle cells. Immunoblot and immunohistochemical analyses of lysates of carotid arteries obtained from infected mice revealed increased expression of PCNA, cyclin D1, its substrate, phospho-Rb (Ser780), and phospho-ERK1/2. The expression of the cyclin-dependent kinase inhibitor p21(Cip1/Waf1), caveolin-1, and caveolin-3 was reduced in carotid arteries obtained from infected mice. There was an increase in the abundance of pre-pro-endothelin-1 mRNA in the carotid artery and aorta from infected mice. The ET(A) receptor was also elevated in infected arteries. ERK activates endothelin-1, which in turn exerts positive feedback activating ERK, and cyclin D1 is a downstream target of both endothelin-1 and ERK. There was significant incorporation of bromodeoxyuridine into smooth muscle cell DNA when treatment was with conditioned medium obtained from infected endothelial cells. Taken together, these data suggest that T. cruzi infection stimulates smooth muscle cell proliferation and is likely a result of the upregulation of the ERK-cyclin D1-endothelin-1 pathway.