In Vitro and In Vivo Anti-parasitic Activity of Artemisinin Combined With Glucantime and Shark Cartilage Extract on Iranian Strain of Leishmania major (MRHO/IR/75/ER)

Background: The adverse effects and increased resistance of drugs necessities the discovery of novel combination therapy. Objectives: This study aimed to examine the effects of Artemisinin plus glucantime or shark cartilage extract on the Iranian strain of Leishmania major (MRHO/IR/75/ER) in vitro and in vivo. Methods: In in vitro experiments, the effects of drugs and their combination in different concentrations (3.12 - 400 µg/mL) on the promastigotes, amastigotes, and un-infected macrophage cells were evaluated. In in vivo experiments, infected BALB/c mice were used as a cutaneous leishmaniasis model to evaluate the effects of the drugs and their combinations with different routes of administrations (namely Artemisinin: oral, ointment, and intraperitoneal; glucantime: intraperitoneal, intramuscular, intralesional, and subcutaneous; shark cartilage extract: oral) on parasite burden, lesion size, and immune system modulation. Results: The results revealed that Artemisinin and glucantime in combination with shark cartilage extract had greater effects on promastigotes than either Artemisinin or glucantime (P < 0.05), and that the combinations also had high cytotoxic effects on promastigotes and uninfected macrophages (P = 0.001). These combinations had more inhibitory effects on amastigotes and infected macrophages than promastigotes. The lesion sizes and parasite burden in the spleen decreased against the combinations of the drugs in different administrations. It was also noticed that the best combination administration route of Artemisinin and glucantime, as strong inducers of INF-γ and Th1 immune response, were ointment and intramuscular, respectively (P < 0.05). Conclusions: The findings indicate that Artemisinin- glucantime or Artemisinin- Shark cartilage combinations are effective inhibitors of L. major. However, further clinical trials are recommended to evaluate the effects of these combinations in human subjects.

Mechanisms of artemether toxicity on single cardiomyocytes and protective effect of nanoencapsulation

BACKGROUND AND PURPOSE

The artemisinin derivative, artemether, has antimalarial activity with potential neurotoxic and cardiotoxic effects. Artemether in nanocapsules (NC-ATM) is more efficient than free artemether for reducing parasitaemia and increasing survival of Plasmodium berghei-infected mice. NCs also prevent prolongation of the QT interval of the ECG. Here, we assessed cellular cardiotoxicity of artemether and how this toxicity was prevented by nanoencapsulation.

EXPERIMENTAL APPROACH

Mice were treated with NC-ATM orally (120 mg·kg-1 twice daily) for 4 days. Other mice received free artemether, blank NCs, and vehicle for comparison. We measured single-cell contraction, intracellular Ca2+ transient using fluorescent Indo-1AM Ca2+ dye, and electrical activity using the patch-clamp technique in freshly isolated left ventricular myocytes. The acute effect of free artemether was also tested on cardiomyocytes of untreated animals.

KEY RESULTS

Artemether prolonged action potentials (AP) upon acute exposure (at 0.1, 1, and 10 μM) of cardiomyocytes from untreated mice or after in vivo treatment. This prolongation was unrelated to blockade of K+ currents, increased Ca2+ currents or promotion of a sustained Na+ current. AP lengthening was abolished by the NCX inhibitor SEA-0400. Artemether promoted irregular Ca2+ transients during pacing and spontaneous Ca2+ events during resting periods. NC-ATM prevented all effects. Blank NCs had no effects compared with vehicle.

CONCLUSION AND IMPLICATIONS

Artemether induced NCX-dependent AP lengthening (explaining QTc prolongation) and disrupted Ca2+ handling, both effects increasing pro-arrhythmogenic risks. NCs prevented these adverse effects, providing a safe alternative to the use of artemether alone, especially to treat malaria.

Synthesis and Antileishmanial Activity of 1,2,4,5-Tetraoxanes against Leishmania donovani

A chemically diverse range of novel tetraoxanes was synthesized and evaluated in vitro against intramacrophage amastigote forms of Leishmania donovani. All 15 tested tetraoxanes displayed activity, with IC₅₀ values ranging from 2 to 45 µm. The most active tetraoxane, compound LC140, exhibited an IC₅₀ value of 2.52 ± 0.65 µm on L. donovani intramacrophage amastigotes, with a selectivity index of 13.5. This compound reduced the liver parasite burden of L. donovani-infected mice by 37% after an intraperitoneal treatment at 10 mg/kg/day for five consecutive days, whereas miltefosine, an antileishmanial drug in use, reduced it by 66%. These results provide a relevant basis for the development of further tetraoxanes as effective, safe, and cheap drugs against leishmaniasis.

Effect of Polyvinyl Alcohol (PVA) Containing Artemether in Treatment of Cutaneous Leishmaniasis Caused by Leishmania major in BALB/c Mice

Background:

Polyvinyl alcohol (PVA) is one of the well-known polymers, which has been used in numerous biomedical applications because of its good biocompatibility.

Objectives:

Due to problems made by the therapeutics already used for leishmaniasis, the aim of this study was to evaluate the effect of PVA containing artemether in treating cutaneous leishmaniasis in BALB/c mice.

Materials and Methods:

Aqueous solution of PVA was prepared by mixing with Double Distilled Water. After preparation of PVA, 4.33 mg of each drug (main drug artemether and control drug 14% glucantime) was added to 100 g of prepared PVA-honey solution. The solution was incubated at 37°C and the release of artemether was evaluated by measuring absorbance at 260 nm wave length. In this study for treatment of mice lesion, we used PVA containing artemether and glucantime and this method was compared with ointment treatment.

Results:

Mean diameters of lesions in mice treated with artemether were smaller than the control group and the differences were significant (P < 0.05). The mean lesion size of mice treated with PVA containing artemether in comparison with the group treated with ointment of artemether were smaller and the differences were significant (P < 0.05).

Conclusions:

PVA containing artemether is a new method for treatment of cutaneous leishmaniasis and according to the obtained results, artemether is an appropriate and effective drug, especially when used with PVA as a lesion dressing; thus we suggest that this method can be applied for the treatment of cutaneous leishmaniasis.