Biodegradable polymeric nanocapsules prevent cardiotoxicity of antitrypanosomal lychnopholide

Abstract

Chagas disease is a neglected parasitic disease caused by the protozoan Trypanosoma cruzi. New antitrypanosomal options are desirable to prevent complications, including a high rate of cardiomyopathy. Recently, a natural substance, lychnopholide, has shown therapeutic potential, especially when encapsulated in biodegradable polymeric nanocapsules. However, little is known regarding possible adverse effects of lychnopholide. Here we show that repeated-dose intravenous administration of free lychnopholide (2.0 mg/kg/day) for 20 days caused cardiopathy and mortality in healthy C57BL/6 mice. Echocardiography revealed concentric left ventricular hypertrophy with preserved ejection fraction, diastolic dysfunction and chamber dilatation at end-stage. Single cardiomyocytes presented altered contractility and Ca 2+ handling, with spontaneous Ca 2+ waves in diastole. Acute in vitro lychnopholide application on cardiomyocytes from healthy mice also induced Ca 2+ handling alterations with abnormal RyR2-mediated diastolic Ca 2+ release. Strikingly, the encapsulation of lychnopholide prevented the cardiac alterations induced in vivo by the free form repeated doses. Nanocapsules alone had no adverse cardiac effects. Altogether, our data establish lychnopholide presented in nanocapsule form more firmly as a promising new drug candidate to cure Chagas disease with minimal cardiotoxicity. Our study also highlights the potential of nanotechnology not only to improve the efficacy of a drug but also to protect against its adverse effects. Chagas disease (CD) is an important neglected disease caused by an intracellular hemoflagellate protozoan parasite, Trypanosoma cruzi (T. cruzi).There are an estimated 6-7 million infected people worldwide, and the disease causes 12 500 deaths per year, mostly in Latin America (World Health Organization, Switzerland 2015). While CD is principally transmitted to humans by triatomine insects, other routes include blood transfusion or transplantation of contaminated organs, ingestion of contaminated food and congenital transmission from infected mothers to newborns. International migrations contribute to spread the disease in non-endemic areas such as North America, Europe and Western Pacific countries (World Health Organization, Switzerland 2015). CD evolves in different consecutive phases with a short acute period, characterized by patent parasitemia, followed by a chronic phase in which most infected individuals remain asymptomatic (indeterminate form). CD is also a common determinant of non-ischemic cardiomyopathy in addition to digestive complications and neurological disorders. Approximately 30% of patients infected with T. cruzi manifest cardiomyopathy characterized by severe myocarditis and multiple arrhythmias, and/or dilatation and physiological dysfunctions of hollow organs, mainly of the digestive tract, which develop progressively over the years or decades after infection [1][2][3][4] . The clinical course of CD shows great variability, and the mechanisms or determinants responsible for t...