Aptamers as novel diagnostic and therapeutic tool and its potential use in parasitology

Aptamers are single stranded DNA or RNA sequences that adopt unique three-dimensional (3D) structures that allow them to recognize a specific target with great affinity. Their potential uses include; diagnosis of diseases, new therapeutic agents, detection of food risks, biosensors, detection of toxins, drug carriers, nanoparticle markers, among others. So far an aptamer called Pegaptanib has been the only one approved by the FDA (Food and Drug Administration) for commercial use. Other aptamers are in different clinical stages of development for the treatment of different diseases. In the area of parasitology, the investigations carried out in parasites such as Leishmania sp. allowed to get aptamers that recognize the LiPABP protein (polyA binding protein), which may have potential application in research, diagnosis and even as a therapeutic agent. In the case of malaria, aptamers have been obtained that allow to identify infected erythrocytes, inhibit the formation of rosettes, and others that promise to be alternatives for diagnosis by specifically detecting the PfLDH protein (lactate dehydrogenase). In C. parvuum, aptamers have been selected that allow the detection of oocysts from contaminated food or water. In E. histolytica, 2 aptamers called C4 and C5 have been isolated which inhibit in vitro proliferation of trophozoites and have potential use as a therapeutic agent. Aptamers obtained against T. cruzi inhibit the invasion of LLC-MK2 cells (monkey kidney) by 50-70% and in T. brucei aptamers with potential to transport toxic molecules to the parasitic lysosome were identified as a novel therapeutic strategy. The data collected in this review highlight aptamers as a novel alternative for research, diagnosis and therapy of parasites of national interest.