Monika Derda

The use of phytotherapy in diseases caused by parasitic protozoa

The paper presents an overview of the use of natural therapeutic agents in combating parasitic diseases. Nowadays there is increasing demand for proven plant therapies, which often are found to be more effective than synthetic pharmaceuticals in chronic diseases. In many cases herbal preparations perfectly supplement the conventional treatment and at the same time do not cause side effects. On the pharmaceutical market there are many drugs of plant origin which have been applied in the treatment of parasitic diseases. However, researchers are still looking for new plants, or specific substances isolated from them, which can be used in therapy. In this paper, drugs of plant origin used in the treatment of amoebiasis, giardiasis, malaria, leishmaniasis, trypanosomiasis and acanthamoebiasis are described.

Artemisia annua L. as a plant with potential use in the treatment of acanthamoebiasis

The treatment of acanthamoebiasis is a great problem. Most cerebral invasions end with death, and the treatment of ocular invasions is usually long-lasting and not very effective. Numerous plant extracts and substances isolated from plants, which are effective against trophozoites or cysts, have been studied in the treatment of acanthamoebiasis. However, no agents that are simultaneously effective against both developing forms of amoebae have been discovered yet. It seems that such a plant which fulfils both tasks is Artemisia annua L. Our studies showed that water, alcohol and chloroform extracts from the herb A. annua L. can be applied in general and local treatment or in combined therapy with antibiotics in the treatment of acanthamoebiasis. Extracts from this plant show not only in vitro but also in vivo effects. Studies carried out on experimental animals infected with amoebae show that the application of these extracts significantly prolongs the survival of the animals.

Effect of nitric oxide releasing drugs on the intensity of infection during experimental trichinellosis in mice

Nitric oxide (NO) has been shown to play a critical role in various physiological and pathological conditions. Apart from its physiological functions, NO indirectly participates in certain aspects of the pathology of infectious diseases. The aim of this work was to examine the influence of NO-releasing drugs on the intensity of infection in mice infected with Trichinella spiralis. The selected substances were nitroglycerin, isosorbide dinitrate, nitrendipine, sildenafil, and pentaerythritol. These were administered over a prolonged period of time: from the 3rd to the 28th day post-infection. Our study showed that NO administered during trichinellosis may enhance the infection in mice as compared to untreated controls. Thus, treatment with pentaerythritol caused a 44% increase in the intensity of infection relative to the untreated controls, sildenafil a 37% increase, and nitrendipine a 30% increase. This effect may be related to the action of NO on the hosts defence mechanisms.

Acanthamoeba infection in lungs of mice expressed by toll-like receptors (TLR2 and TLR4).

Toll-like receptors (TLRs) play a key role in the innate immune responses to a variety of pathogens including parasites. TLRs are among the most highly conserved in the evolution of the receptor family, localized mainly on cells of the immune system and on other cells such as lung cells. The aim of this study was to determine for the first time the expression of TLR2 and TLR4 in the lung of Acanthamoeba spp. infected mice using quantitative real-time polymerase chain reaction (Q-PCR) and immunohistochemical (IHC) staining. The Acanthamoeba spp. were isolated from a patient with Acanthamoeba keratitis (AK) (strain Ac 55) and from environmental samples of water from Malta Lake (Poznań, Poland - strain Ac 43). We observed a significantly increased level of expression of TLR2 as well as TLR4 mRNA from 2 to 30 days post Acanthamoeba infection (dpi) in the lungs of mice infected with Ac55 (KP120880) and Ac43 (KP120879) strains. According to our observations, increased TLR2 and TLR4 expression in the pneumocytes, interstitial cells and epithelial cells of the bronchial tree may suggest an important role of these receptors in protective immunity against Acanthamoeba infection in the lung. Moreover, increased levels of TLR2 and TLR4 mRNA expression in infected Acanthamoeba mice may suggest the involvement of these TLRs in the recognition of this amoeba pathogen-associated molecular pattern (PAMP).

Comparative analyses of different genetic markers for the detection of Acanthamoeba spp. isolates.

Acanthamoeba are widespread free-living amoebae which may cause granulomatous amoebic encephalitis (GAE), keratitis, skin ulcerations and disseminated tissue infection. An important diagnostic and prognostic factor for the treatment of infection is a quick and correct diagnosis of amoebae strains. The aim of our study was to develop a rapid method for detection and identification of pathogenic Acanthamoeba spp. strains from diagnostic material collected from water. In this study we analysed five amplification-based genetic markers (Aca 16S, Ac6/210, GP, JDP, Nelson) used for identification of pathogenic Acanthamoeba spp. strains isolated in water sources in Poland, Iceland and Sweden. Our results demonstrated the presence of pathogenic Acanthamoeba strains in tap water. PCR assay appeared to be a more rapid and sensitive method to detect the presence of amoebae than the limited conventional techniques. Based on our observations, we can confirm that the use of four out of five genetic markers (Aca 16S, Ac 6/210, JDP, GP, Nelson) may be helpful in identification of Acanthamoeba spp. strains, but only one Aca 16S primer pair is a highly specific marker that distinguishes between pathogenic strains of Acanthamoeba and other free-living amoeba families.

Changes in the activity and kinetics of mouse intestinal glutathione transferase during experimental trichinellosis

The glutathione S-transferases (GSTs) are a group of multifunctional enzymes, which play a critical role in cellular detoxification. Our investigations deal with the contribution of GST in the biochemical defense against Trichinella spiralis infection. The aim of this study was to examine the effect of T. spiralis infection on the total activity and kinetic properties of cytosolic GST in the intestine during the intestinal phase of experimental trichinellosis in mice. Our results showed a statistically significant increase (relative to the uninfected control) in the total GST activity both in the small and large intestines of the infected mice. Moreover, we observed changes in the kinetics of substrate saturation of GST. Trichinellosis in the small intestine caused a 12-fold decrease in the low Km value and a sixfold increase in the high Km value. In the large intestine, infection with T. spiralis caused only a fivefold increase in the low Km value, whereas the high Km value remained unchanged. We suggest that GST from the mouse small intestine could be involved in the detoxification of parasite excretory–secretory products released to the host intestine during trichinellosis and that these products influence the quaternary structure of this enzyme.

Parasitic diseases in humans transmitted by vectors.

Despite the considerable progress of medicine, parasitic diseases still pose a great threat to human health and life. Among parasitic diseases, those transmitted by vectors, mainly arthropods, play a particular role. These diseases occur most frequently in the poorest countries and affect a vast part of the human population. They include malaria, babesiosis, trypanosomiasis, leishmaniasis and filariasis. This study presents those vector-transmitted diseases that are responsible for the greatest incidence and mortality of people on a global scale. Attention is focused primarily on diseases transmitted by mosquitoes, flies, Hemiptera and ticks.

Evaluation of the effectiveness of tea tree oil in treatment of Acanthamoeba infection

Eye diseases caused by amoebae from the genus Acanthamoeba are usually chronic and severe, and their treatment is prolonged and not very effective. The difficulties associated with therapy have led to attempts at finding alternative treatment methods. Particularly popular is searching for cures among drugs made of plants. However, no substances with total efficacy in treating Acanthamoeba keratitis have been identified.Results of our semi in vivo studies of tea tree oil simulating eyeball infection demonstrated 100% effectiveness in the case of both trophozoites and cysts of amoebae from the genus Acanthamoeba. The action of tea tree oil indicates that this is the first substance with a potential ability to quickly and effectively remove the amoebae from the eye. Tea tree oil has the ability to penetrate tissues, which allows it to destroy amoebae in both the shallow and deep layers of the cornea. The present research into the use of tea tree oil in the therapy of Acanthamoeba infection is the first study of this type in parasitology. It offers tremendous potential for effective treatment of Acanthamoeba keratitis and other diseases caused by these protozoa.

Presence of potential pathogenic genotypes of free-living amoebae isolated from sandboxes in children's playgrounds

Some free-living amoebae are a potential threat to human health. The best known species are those of the genus Acanthamoeba Volkonsky, 1931, which cause Acanthamoeba keratitis, granulomatous amoebic encephalitis and other forms of tissue inflammation. The aim of the present study was to search for potential pathogenic genotypes of free-living amoeba in the sand in childrens playgrounds. Our results confirmed that free-living amoebae were present in all examined playgrounds. Sequences of the 18S rDNA have shown that all isolated potentially pathogenic strains of amoebae belong to genotype T4 of Acanthamoeba. The potential pathogenicity of isolates was confirmed on mice. The presence of pathogenic amoebae in the examined sand may be a potential source of human infection.