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The Role of Efflux Pumps in Schistosoma mansoni Praziquantel Resistant Phenotype.

Pinto-Almeida A, Mendes T, Armada A, Belo S, Carrilho E, Viveiros M, Afonso A - PLoS ONE (2015)

Bottom Line: Praziquantel (PZQ) is the drug of choice to treat this disease due to its high cure rates and no significant side effects.Low doses of Verapamil successfully reverted drug resistance.Our results might give an indication that a combination therapy with PZQ and natural or synthetic Pgp modulators can be an effective strategy for the treatment of confirmed cases of resistance to PZQ in S. mansoni.

View Article: PubMed Central - PubMed

Affiliation: Graduate Program in Areas of Basic and Applied Biology, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal; Medical Parasitology Unit, Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Lisbon, Portugal; Universidade de São Paulo, Instituto de Química de São Carlos, São Carlos, SP, Brazil.

ABSTRACT

Background: Schistosomiasis is a neglected disease caused by a trematode of the genus Schistosoma that is second only to malaria in public health significance in Africa, South America, and Asia. Praziquantel (PZQ) is the drug of choice to treat this disease due to its high cure rates and no significant side effects. However, in the last years increasingly cases of tolerance to PZQ have been reported, which has caused growing concerns regarding the emergency of resistance to this drug.

Methodology/principal findings: Here we describe the selection of a parasitic strain that has a stable resistance phenotype to PZQ. It has been reported that drug resistance in helminths might involve efflux pumps such as members of ATP-binding cassette transport proteins, including P-glycoprotein and multidrug resistance-associated protein families. Here we evaluate the role of efflux pumps in Schistosoma mansoni resistance to PZQ, by comparing the efflux pumps activity in susceptible and resistant strains. The evaluation of the efflux activity was performed by an ethidium bromide accumulation assay in presence and absence of Verapamil. The role of efflux pumps in resistance to PZQ was further investigated comparing the response of susceptible and resistant parasites in the absence and presence of different doses of Verapamil, in an ex vivo assay, and these results were further reinforced through the comparison of the expression levels of SmMDR2 RNA by RT-PCR.

Conclusions/significance: This work strongly suggests the involvement of Pgp-like transporters SMDR2 in Praziquantel drug resistance in S. mansoni. Low doses of Verapamil successfully reverted drug resistance. Our results might give an indication that a combination therapy with PZQ and natural or synthetic Pgp modulators can be an effective strategy for the treatment of confirmed cases of resistance to PZQ in S. mansoni.

No MeSH data available.


Related in: MedlinePlus

Selection of S. mansoni PZQ-resistant strain.This selection was carried out under continuous PZQ increased pressure using CD1 mice over several passages. 1—Transcutaneous infection of mice with ~100 cercariae; 2 –Oral administration of PZQ after infection confirmation by the presence of eggs in the faeces (± 60 dpi); 3 –Mice were euthanized to collect adult worms and miracidia (eggs in faeces) (± 75 dpi); 4—B. glabrata snails were infected with miracidia released from eggs; 5—Cercariae were released from snails (± 45 dpi).
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pone.0140147.g001: Selection of S. mansoni PZQ-resistant strain.This selection was carried out under continuous PZQ increased pressure using CD1 mice over several passages. 1—Transcutaneous infection of mice with ~100 cercariae; 2 –Oral administration of PZQ after infection confirmation by the presence of eggs in the faeces (± 60 dpi); 3 –Mice were euthanized to collect adult worms and miracidia (eggs in faeces) (± 75 dpi); 4—B. glabrata snails were infected with miracidia released from eggs; 5—Cercariae were released from snails (± 45 dpi).

Mentions: Infected CD1 mice were checked approximately 60 days post parasite infection by Kato-Katz procedure; if eggs were found in faeces, mice were then treated orally with PZQ solution at appropriate dosage. If, on day 15, post PZQ treatment, viable eggs (verified by live miracidia inside the eggs and Kato-Katz procedure) continued to be eliminated, mice were euthanized and miracidia present in the liver were used to subsequently infect B. glabrata snails. Once B. glabrata snails start eliminating S. mansoni cercariae (30 to 60 days after snail infection), new CD1 mice were re-infected and the previous procedure was repeated, continuing the PZQ- resistant strain selection in vivo (Fig 1).


The Role of Efflux Pumps in Schistosoma mansoni Praziquantel Resistant Phenotype.

Pinto-Almeida A, Mendes T, Armada A, Belo S, Carrilho E, Viveiros M, Afonso A - PLoS ONE (2015)

Selection of S. mansoni PZQ-resistant strain.This selection was carried out under continuous PZQ increased pressure using CD1 mice over several passages. 1—Transcutaneous infection of mice with ~100 cercariae; 2 –Oral administration of PZQ after infection confirmation by the presence of eggs in the faeces (± 60 dpi); 3 –Mice were euthanized to collect adult worms and miracidia (eggs in faeces) (± 75 dpi); 4—B. glabrata snails were infected with miracidia released from eggs; 5—Cercariae were released from snails (± 45 dpi).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4596880&req=5

pone.0140147.g001: Selection of S. mansoni PZQ-resistant strain.This selection was carried out under continuous PZQ increased pressure using CD1 mice over several passages. 1—Transcutaneous infection of mice with ~100 cercariae; 2 –Oral administration of PZQ after infection confirmation by the presence of eggs in the faeces (± 60 dpi); 3 –Mice were euthanized to collect adult worms and miracidia (eggs in faeces) (± 75 dpi); 4—B. glabrata snails were infected with miracidia released from eggs; 5—Cercariae were released from snails (± 45 dpi).
Mentions: Infected CD1 mice were checked approximately 60 days post parasite infection by Kato-Katz procedure; if eggs were found in faeces, mice were then treated orally with PZQ solution at appropriate dosage. If, on day 15, post PZQ treatment, viable eggs (verified by live miracidia inside the eggs and Kato-Katz procedure) continued to be eliminated, mice were euthanized and miracidia present in the liver were used to subsequently infect B. glabrata snails. Once B. glabrata snails start eliminating S. mansoni cercariae (30 to 60 days after snail infection), new CD1 mice were re-infected and the previous procedure was repeated, continuing the PZQ- resistant strain selection in vivo (Fig 1).

Bottom Line: Praziquantel (PZQ) is the drug of choice to treat this disease due to its high cure rates and no significant side effects.Low doses of Verapamil successfully reverted drug resistance.Our results might give an indication that a combination therapy with PZQ and natural or synthetic Pgp modulators can be an effective strategy for the treatment of confirmed cases of resistance to PZQ in S. mansoni.

View Article: PubMed Central - PubMed

Affiliation: Graduate Program in Areas of Basic and Applied Biology, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal; Medical Parasitology Unit, Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Lisbon, Portugal; Universidade de São Paulo, Instituto de Química de São Carlos, São Carlos, SP, Brazil.

ABSTRACT

Background: Schistosomiasis is a neglected disease caused by a trematode of the genus Schistosoma that is second only to malaria in public health significance in Africa, South America, and Asia. Praziquantel (PZQ) is the drug of choice to treat this disease due to its high cure rates and no significant side effects. However, in the last years increasingly cases of tolerance to PZQ have been reported, which has caused growing concerns regarding the emergency of resistance to this drug.

Methodology/principal findings: Here we describe the selection of a parasitic strain that has a stable resistance phenotype to PZQ. It has been reported that drug resistance in helminths might involve efflux pumps such as members of ATP-binding cassette transport proteins, including P-glycoprotein and multidrug resistance-associated protein families. Here we evaluate the role of efflux pumps in Schistosoma mansoni resistance to PZQ, by comparing the efflux pumps activity in susceptible and resistant strains. The evaluation of the efflux activity was performed by an ethidium bromide accumulation assay in presence and absence of Verapamil. The role of efflux pumps in resistance to PZQ was further investigated comparing the response of susceptible and resistant parasites in the absence and presence of different doses of Verapamil, in an ex vivo assay, and these results were further reinforced through the comparison of the expression levels of SmMDR2 RNA by RT-PCR.

Conclusions/significance: This work strongly suggests the involvement of Pgp-like transporters SMDR2 in Praziquantel drug resistance in S. mansoni. Low doses of Verapamil successfully reverted drug resistance. Our results might give an indication that a combination therapy with PZQ and natural or synthetic Pgp modulators can be an effective strategy for the treatment of confirmed cases of resistance to PZQ in S. mansoni.

No MeSH data available.


Related in: MedlinePlus