Effect of gangliosides on Trypanosoma cruzi infection in mice

Why does GM1 induce a potent beneficial response to experimental Chagas disease?

Being one of the world's neglected diseases, Chagas has neither a vaccine nor a satisfactory therapy. Inoculation of murine models with the ganglioside GM1 has shown a strikingly nonlinear effect, leading to a strong decrease in parasite load at low doses but reverting to a load increase at high doses. Cardiocyte destruction concomitant with the disease is also significantly reduced by a moderate application of GM1. A mathematical model for the interaction between the parasite and the immune system is shown to explain these effects and is used to predict an optimal dosage that maximizes parasite removal with minimal cardiocyte destruction.

A critical review on Chagas disease chemotherapy

In this "Critical Review" we made a historical introduction of drugs assayed against Chagas disease beginning in 1912 with the works of Mayer and Rocha Lima up to the experimental use of nitrofurazone. In the beginning of the 70s, nifurtimox and benznidazole were introduced for clinical treatment, but results showed a great variability and there is still a controversy about their use for chronic cases. After the introduction of these nitroheterocycles only a few compounds were assayed in chagasic patients. The great advances in vector control in the South Cone countries, and the demonstration of parasite in chronic patients indicated the urgency to discuss the etiologic treatment during this phase, reinforcing the need to find drugs with more efficacy and less toxicity. We also review potential targets in the parasite and present a survey about new classes of synthetic and natural compounds studied after 1992/1993, with which we intend to give to the reader a general view about experimental studies in the area of the chemotherapy of Chagas disease, complementing the previous papers of Brener (1979) and De Castro (1993).

GM1 ganglioside induced myocardial restoration and survival of mice with experimental Chagas' disease

In a previous work, our group reported that Albino Swiss male mice inoculated with T. cruzi to develop acute lethal infection by day 15 decreased parasitemia and survived when treated with total brain gangliosides (GT; 1 mg, daily). In this paper, GT were replaced by GM1 in 0.1 mg dose that caused diminished parasitemia from day 15 to 30 and survival of 80% by day 120 p.i. Treatment with GT 0.15 mg was ineffective. This indicates that GT effect was due to GM1 and that more sialyl residues on the same lipid moiety produces adverse results. GM1 was compared to other sialylated molecules: fetuine and colominic acid. Both of them increased parasitemias and death by day 16 p.i., suggesting that sialic residues favor parasite replication. Asialo-GM1 (0.1 mg daily) was also adverse. This pointed to GM1 not to other ganglioside or sphingolipid or sialoprotein as the active agent. Gangliosides are [Ca+2]i modulators, so GM1 was compared to nifedipine which blocks calcium channels only in the host. Nifedipine treated mice behaved as controls. It is proposed that if GM1 calcium modulation is involved it must be on the parasite rather than on the host. Electrocardiographic (ECG) records show that while infected mice die with bradycardia, treated mice survive and recover normal frequency. Uninfected treated mice showed no electrocardiographic alterations.