| Autor: |
Loise Ndung'u, Benard Langat, Esther Magiri, Joseph Ng'ang'a, Beatrice Irungu, Alexis Nzila, Daniel Kiboi |
| Jazyk: |
angličtina |
| Rok vydání: |
2018 |
| Předmět: |
|
| Zdroj: |
Wellcome Open Research, Vol 2 (2018) |
| Druh dokumentu: |
article |
| ISSN: |
2398-502X |
| DOI: |
10.12688/wellcomeopenres.11768.2 |
| Popis: |
Background: The human malaria parasite Plasmodium falciparum has evolved drug evasion mechanisms to all available antimalarials. The combination of amodiaquine-artesunate is among the drug of choice for treatment of uncomplicated malaria. In this combination, a short-acting, artesunate is partnered with long-acting, amodiaquine for which resistance may emerge rapidly especially in high transmission settings. Here, we used a rodent malaria parasite Plasmodium berghei ANKA as a surrogate of P. falciparum to investigate the mechanisms of amodiaquine resistance. Methods: We used the ramp up approach to select amodiaquine resistance. We then employed the 4-Day Suppressive Test to measure the resistance level and determine the cross-resistance profiles. Finally, we genotyped the resistant parasite by PCR amplification, sequencing and relative quantitation of mRNA transcript of targeted genes. Results: Submission of the parasite to amodiaquine pressure yielded resistant line within thirty-six passages. The effective doses that reduced 90% of parasitaemia (ED90) of the sensitive and resistant lines were 4.29mg/kg and 19.13mg/kg respectively. The selected parasite retained resistance after ten passage cycles in the absence of the drug and freezing at -80ºC for one month with ED90 of 20.34mg/kg and 18.22mg/kg. The parasite lost susceptibility to chloroquine by (6-fold), artemether (10-fold), primaquine (5-fold), piperaquine (2-fold) and lumefantrine (3-fold). Sequence analysis of Plasmodium berghei chloroquine-resistant transporter revealed His95Pro mutation. We found no variation in the nucleotide sequences of Plasmodium berghei multidrug resistance gene-1 (Pbmdr1), Plasmodium berghei deubiquitinating enzyme-1 or Plasmodium berghei Kelch13 domain. However, high mRNA transcripts of essential transporters; Pbmdr1, V-type/H+ pumping pyrophosphatase-2 and sodium hydrogen ion exchanger-1 and Ca2+/H+ antiporter accompanies amodiaquine resistance. Conclusions: The selection of amodiaquine resistance yielded stable “multidrug-resistant’’ parasites and thus may be used to study shared resistance mechanisms associated with other antimalarial drugs. Genome-wide analysis of the parasite may elucidate other functionally relevant genes controlling AQ resistance in P. berghei. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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