1
|
Antischistosomal activity of artemisinin derivatives in vivo and in patients. Pharmacol Res 2016; 110:216-226. [DOI: 10.1016/j.phrs.2016.02.017] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 02/07/2016] [Accepted: 02/16/2016] [Indexed: 11/20/2022]
|
2
|
Disruption of spermatogenesis in the liver fluke, Fasciola hepatica by two artemisinin derivatives, artemether and artesunate. J Helminthol 2016; 91:55-71. [PMID: 26979164 DOI: 10.1017/s0022149x16000079] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
An in vivo study in the laboratory rat model has been carried out to monitor changes to the spermatogenic cells in the testis tubules of adult Fasciola hepatica following treatment with the artemisinins, artemether and artesunate. Rats infected with the triclabendazole (TCBZ)-resistant Sligo isolate were dosed orally with artemether at a concentration of 200 mg/kg and flukes recovered at 24, 48 and 72 h post treatment (pt). Rats infected with the TCBZ-resistant Oberon isolate were dosed orally with artesunate at a concentration of 200 mg/kg and flukes recovered 24, 48, 72 and 96 h pt. The flukes were processed for histological and transmission electron microscope (TEM) examination. Changes to the spermatogenic cells were evident at 24 h pt with artemether. The spermatogonial and spermatocyte cells contained abnormal mitochondria, there were fewer spermatids and spermatozoa in the tubules than normal, and a number of cells showed signs of apoptosis. There was a further decline in cell numbers at 48 h pt and the organization of the spermatocyte and spermatid rosettes was atypical. Sperm formation had become abnormal and those spermatozoa present possessed only a single axoneme. By 72 h pt, the testis tubules were vacuolated and filled with abnormal cells and cell debris. Only spermatogonial cells could be identified and there was widespread evidence of apoptosis in the cells. Distinct cellular changes following artesunate treatment did not become apparent until 48 h pt. The changes seen were similar to those described for artemether, but were generally less severe at matching time-periods. The fine structural changes occurring in the spermatogenic cells were compared to those observed in other cell types and fluke tissues and the overall information was collated to identify the cellular targets for artemisinin action and to establish the time-line for drug action.
Collapse
|
3
|
O'Neill J, Johnston R, Halferty L, Brennan G, Fairweather I. Ultrastructural changes in the tegument and gut of adult Fasciola hepatica following in vivo treatment with artesunate. Exp Parasitol 2015; 154:143-54. [DOI: 10.1016/j.exppara.2015.04.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 03/26/2015] [Accepted: 04/19/2015] [Indexed: 10/23/2022]
|
4
|
O'Neill JF, Johnston RC, Halferty L, Hanna REB, Brennan GP, Fairweather I. A comparative study on the impact of two artemisinin derivatives, artemether and artesunate, on the female reproductive system of Fasciola hepatica. Vet Parasitol 2015; 211:182-94. [PMID: 26093822 DOI: 10.1016/j.vetpar.2015.05.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 05/22/2015] [Accepted: 05/30/2015] [Indexed: 10/23/2022]
Abstract
An in vivo study in the laboratory rat model has been carried out to monitor changes to the female reproductive system in adult Fasciola hepatica following treatment with the artemisinins, artemether and artesunate. Rats infected with the triclabendazole (TCBZ)-resistant Sligo isolate were dosed orally with artemether at a concentration of 200mg/kg and flukes recovered at 24, 48 and 72 h post-treatment (pt). Rats infected with the TCBZ-resistant Oberon isolate were dosed orally with artesunate at a concentration of 200mg/kg and flukes recovered 24, 48, 72 and 96 h pt. The flukes were processed for histological and transmission electron microscope (TEM) examination of the uterus, Mehlis' gland, ovary and vitellaria. After treatment with artemether, egg production had become abnormal by 72 h pt, with free vitelline cells and masses of shell protein material within the uterus; spermatozoa were absent. The Mehlis' gland and ovary retained a normal morphology over the 3-day period. A change in the cell population in the vitelline follicles was seen at 48 h pt, with a decline in the number of immature cells. This became more marked by 72 h and the follicles became progressively vacuolated over the 3-day period. At the TEM level, there were changes in the immature vitelline cells at 24h pt, as evidenced by a decrease in shell protein production and the presence of lipid droplets and abnormal mitochondria. Spaces in the follicles separated the cells from each other. The changes became progressively more severe with time, so that, by 72 h pt, the follicles were very disrupted, containing cells in the advanced stages of apoptotic breakdown. In extreme cases, the follicles were scarcely recognisable and had become filled with cellular debris. Fine structural changes to the vitelline cells induced by artesunate treatment were similar to those described for artemether, but generally occurred more quickly and were greater; this was particularly true of the swelling of the ger cisternae. Overall, the results have shown that artemisinin treatment has a severe impact on egg production by TCBZ-resistant flukes, an effect that is mediated by disruption of the vitelline cells.
Collapse
Affiliation(s)
- J F O'Neill
- Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, Belfast BT9 7BL, Northern Ireland, United Kingdom
| | - R C Johnston
- Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, Belfast BT9 7BL, Northern Ireland, United Kingdom
| | - L Halferty
- Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, Belfast BT9 7BL, Northern Ireland, United Kingdom
| | - R E B Hanna
- Veterinary Sciences Division, Agri-Food and Biosciences Institute (AFBI), Stormont, Belfast BT4 3SD, United Kingdom
| | - G P Brennan
- Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, Belfast BT9 7BL, Northern Ireland, United Kingdom
| | - I Fairweather
- Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, Belfast BT9 7BL, Northern Ireland, United Kingdom.
| |
Collapse
|
5
|
Roy B, Giri BR. α-Viniferin-Induced Structural and Functional Alterations in Raillietina echinobothrida, a Poultry Tapeworm. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2015; 21:377-84. [PMID: 25592142 DOI: 10.1017/s1431927614014603] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
α-Viniferin, an active component of the plant Carex baccans L., is known for its anticancer, antidiabetic, and anti-inflammatory properties. In Northeast India, different tribes traditionally consume C. baccans to control intestinal helminth infections. Therefore, the present study was carried out to assess the extent of tegumental alteration caused by α-viniferin in Raillietina echinobothrida, a widely prevalent poultry helminth in northeast India. Helminths were exposed in vitro to various doses of α-viniferin (50, 100, and 200 µM/mL of physiological buffered saline) and their motility and mortality were recorded. Stereoscan observations on the parasite exposed to the active compound showed extensive distortion and destruction of the surface fine topography of the tegument compared with controls. The compound also caused extensive damage to the tegument by disintegration of microtriches, disorganization of muscle bundles, and loss of cellular organelles combined with distortion and disruption of the plasma membrane, nuclear membrane, nucleolus, mitochondrial membrane, and cristae. Histochemical and biochemical studies carried out parasites exposed to α-viniferin revealed a decline in the activity of vital tegumental enzymes like acid phosphatase, alkaline phosphatase, and adenosine triphosphatase. Extensive structural and functional alterations observed in the treated parasites are indicative of efficient cestocidal activity of the compound.
Collapse
Affiliation(s)
- Bishnupada Roy
- Parasitology Laboratory,Department of Zoology,North-Eastern Hill University,Shillong-793022,Meghalaya,India
| | - Bikash R Giri
- Parasitology Laboratory,Department of Zoology,North-Eastern Hill University,Shillong-793022,Meghalaya,India
| |
Collapse
|
6
|
El-Shabasy EA, Reda ES, Abdeen SH, Said AE, Ouhtit A. Transmission electron microscopic observations on ultrastructural alterations in Schistosoma mansoni adult worms recovered from C57BL/6 mice treated with radiation-attenuated vaccine and/or praziquantel in addition to passive immunization with normal and vaccinated rabbit sera against infection. Parasitol Res 2015; 114:1563-80. [PMID: 25786393 DOI: 10.1007/s00436-015-4341-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 01/22/2015] [Indexed: 01/07/2023]
Abstract
Although the current treatment of schistosomiasis relies largely on praziquantel (PZQ), it has not been successful in significantly reducing the overall rate of disease cases, one of the suggested reasons being the inevitable resistance to PZQ. Previous studies showed that radiation-attenuated vaccine provides protection against Schistosoma mansoni in a host of various species. In the present study, we evaluated the effect of various vaccination strategies in C57BL/6 mice, including single or multiple vaccination strategy, subcurative dose (20 mg/kg) of PZQ, and a combination of single vaccination with subcurative dose of PZQ. Treatment either with subcurative dose of PZQ or with a single vaccination of attenuated cercariae (500 per mouse), caused significant reduction in total worm burden, hepatic, and intestinal ova counts of 43.03, 73.2, and 59.5 and 37.97, 52.02, and 26.3%, respectively. Furthermore, tegumental changes were observed. In multiple vaccinated group, there was an extensive lysis in tegumental layers. High deformations in gastrodermis, testis cells, vitelline cells, and oocytes were recorded. Also, this study is to explore the role of humoral immunity using highly resistant rabbits that had been exposed to three immunizations with ultraviolet (UV)-irradiated cercariae (8000 per rabbit in each immunization), and their sera were tested for their ability to transfer protection. The reduction in challenge worm burden had reached 32.76-43.64% when compared with recipients of normal serum or no serum. The reduction in hepatic and intestinal ova counts reached to 74.4 and 71.08% in group immunized with vaccinated rabbit sera. Swelling and extensive lysis of tegumental layers, gastrodermis lumen, spermatocytes, and deformation of oocytes were recorded with more severity than that recorded in normal rabbit sera group. Our findings recorded that multiple vaccination strategy is the most effective strategy then passive transfer of vaccinated rabbit. This gives guiding in the design the appropriate therapeutic strategy.
Collapse
Affiliation(s)
- Eman A El-Shabasy
- Department of Zoology, Faculty of Science, Mansoura University, Mansoura, Egypt,
| | | | | | | | | |
Collapse
|
7
|
Madbouly NA, Shalash IR, El Deeb SO, El Amir AM. Effect of artemether on cytokine profile and egg induced pathology in murine schistosomiasis mansoni. J Adv Res 2014; 6:851-7. [PMID: 26644922 PMCID: PMC4642152 DOI: 10.1016/j.jare.2014.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 07/19/2014] [Accepted: 07/19/2014] [Indexed: 01/28/2023] Open
Abstract
Artemether (ART), the methylated derivative of artemisinin, is an efficacious antimalarial drug that also displays antischistosomal properties. This study was designed to evaluate the immunomodulatory action of a single intramuscular dose (50 mg/kg body weight) of ART in comparison with PZQ treatment (42 days PI). ART administration was 7, 14, 21 and 45 days PI. ART effect was studied parasitologically, histopathologically and immunologically. It was found that maximum effect was reached when ART treatment interfered with 14 or 21 days old schistosomula. ART treatment 14 or 21 days PI was associated with shift from Th2 to Th1 predominancy (decrease in IL-4 and upgrading of serum IFN-γ levels). In conclusion, ART is a promising drug in control of schistosomiasis mansoni due to its reductive effect on worm burden and its role in improvement of hepatic granulomatous lesions.
Collapse
Affiliation(s)
| | | | | | - Azza M El Amir
- Zoology Department, Faculty of Science, Cairo University, Egypt
| |
Collapse
|
8
|
In vitro tegumental alterations on adult Fasciola gigantica caused by mefloquine. J Parasit Dis 2014; 40:145-51. [PMID: 27065615 DOI: 10.1007/s12639-014-0466-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 04/08/2014] [Indexed: 12/19/2022] Open
Abstract
Emergence of drug-resistant Fasciola strains has drawn the attention of many authors to alternative drugs. The purpose of this study is to explore the in vitro effect of the antimalarial mefloquine against adult Fasciola gigantica. Light and scanning electron microscopic observations could be used to determine the target of the drug following 6 and 12 h of incubation in medium containing mefloquine at three different concentrations 10, 20 and 30 μg/mL, as morphological changes could be observed. These changes occurred in definite sequences in response to mefloquine, and were consisted of swelling, vacuolization that was later disrupted, leading to desquamation of the tegument, resulting in exposure and disruption of basal lamina and the dislodging of spines. It is concluded that mefloquine presented itself as a drug that might become important in trematode chemotherapy, with the tegument being an important drug target.
Collapse
|
9
|
Xavier AML, Tavares D, Guimarães EV, Sarro-Silva MDF, Silva AC, de Moraes Neto AHA. Ultrastructural alterations in adult Schistosoma mansoni, harbored in non-antihelminthic treated and low-inflammatory mice by transmission electron microscopy (TEM). Acta Trop 2014; 130:51-7. [PMID: 24161877 DOI: 10.1016/j.actatropica.2013.10.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 07/31/2013] [Accepted: 10/15/2013] [Indexed: 01/24/2023]
Abstract
This original study suggests that alterations observed on tegumental structure and egg quality of adult Schistosoma mansoni harvested from TS mice are due to their high immune tolerogenic and low-inflammatory capacity. The tegument of worms harvested from genetically selected mice for extreme phenotypes of immune oral tolerance, resistance (TR) and susceptibility (TS) were analyzed by transmission electron microscopy (TEM). Parasites recovered from TR mice showed no tegumental morphological changes. However, specimens collected from TS mice exhibited tubercle swelling with blunted and shortened spines in lower density. These tegumental alterations were similar to those described with artemether or praziquantel treatment, but without to affecting the worm surveillance, supporting observations that the host immune system influences the development and function of the tegument of worms harbored in non-antihelminthic treated TS mice. TS mice showed a higher percentage of dead eggs and a lower percentage of immature eggs than TR mice, but had similar quantities of collected eggs. This suggests that in TS mice the alterations in adult worm tegument prevented egg development, but not egg production or worm survival. These results corroborate our previous scanning electron microscopy (SEM) study indicating the influence of the host immune regulatory profile on the development and function of the worm's reproductive system and tegument.
Collapse
|
10
|
Dasgupta S, Giri BR, Roy B. Ultrastructural observations on Raillietina echinobothrida exposed to crude extract and active compound of Securinega virosa. Micron 2013; 50:62-7. [DOI: 10.1016/j.micron.2013.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 05/16/2013] [Accepted: 05/17/2013] [Indexed: 10/26/2022]
|
11
|
Thétiot-Laurent SAL, Boissier J, Robert A, Meunier B. Chemotherapie gegen Schistosomiasis. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201208390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
|
12
|
Thétiot-Laurent SAL, Boissier J, Robert A, Meunier B. Schistosomiasis chemotherapy. Angew Chem Int Ed Engl 2013; 52:7936-56. [PMID: 23813602 DOI: 10.1002/anie.201208390] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Indexed: 01/08/2023]
Abstract
After malaria, schistosomiasis (or bilharzia) is the second most prevalent disease in Africa, and is occurring in over 70 countries in tropical and subtropical regions. It is estimated that 600 million people are at risk of infection, 200 million people are infected, and at least 200,000 deaths per year are associated with the disease. All schistosome species are transmitted through contact with fresh water that is infested with free-swimming forms of the parasite, which is known as cercariae and produced by snails. When located in the blood vessels of the host, larval and adult schistosomes digest red cells to acquire amino acids for growth and development. Vaccine candidates have been unsuccessful up to now. Against such devastating parasitic disease, the antischistosomal arsenal is currently limited to a single drug, praziquantel, which has been used for more than 35 years. Because the question of the reduction of the activity of praziquantel was raised recently, it is thus urgent to create new and safe antischistosomal drugs that should be combined with praziquantel to develop efficient bitherapies.
Collapse
Affiliation(s)
- Sophie A-L Thétiot-Laurent
- Laboratoire de Chimie de Coordination du CNRS, 205 route de Narbonne, BP 44099, 31077 Toulouse cedex 4, France
| | | | | | | |
Collapse
|
13
|
El-Beshbishi SN, Taman A, El-Malky M, Azab MS, El-Hawary AK, El-Tantawy DA. First insight into the effect of single oral dose therapy with artemisinin-naphthoquine phosphate combination in a mouse model of Schistosoma mansoni infection. Int J Parasitol 2013; 43:521-30. [PMID: 23500074 DOI: 10.1016/j.ijpara.2013.01.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 01/10/2013] [Accepted: 01/11/2013] [Indexed: 12/21/2022]
Abstract
Praziquantel is the current drug of choice against schistosomiasis. The dependency on praziquantel exclusively is problematic, given the spread of the disease and the threat of drug resistance. This study investigates an alternative antischistosomal drug using the compound naphthoquine phosphate tablet, which is a novel single oral dose antimalarial drug, containing a combination of naphthoquine phosphate and artemisinin. In the present study, the therapeutic efficacies of different artemisinin-naphthoquine phosphate combination-dosing protocols were evaluated in experimentally infected mice harbouring juvenile or adult stages of Schistosoma mansoni (Egyptian strain). The study shows that the oral administration of artemisinin-naphthoquine phosphate combination in a single dose of 400 mg/kg on day 7 p.i. resulted in a significant worm burden reduction of 95.07%. When used at a dose of 600 mg/kg on day 21 p.i., all female worms were killed before depositing eggs, resulting in complete absence of eggs in hepatic and intestinal tissues. The same dose given on day 42 p.i. reduced total and female worm burdens by 93.36% and 94.17%, respectively. In addition, artemisinin-naphthoquine phosphate combination induced significant reductions of 80.18% and 76.73% in the hepatic and intestinal tissue egg loads, respectively. Artemisinin-naphthoquine phosphate combination also induced significant alterations in the oogram pattern with elevated levels of dead eggs. Antipathological activities were evident in the amelioration of hepatic granulomata. Our findings hold promise for the development of a novel antischistosomal drug using an artemisinin-naphthoquine phosphate combination. Further in vitro and in vivo studies should be launched to elucidate the possible mechanism/s of action and to study the effect of artemisinin-naphthoquine phosphate combination on other human schistosomes.
Collapse
Affiliation(s)
- Samar N El-Beshbishi
- Department of Medical Parasitology, Faculty of Medicine, Mansoura University, Mansoura 35516, Egypt.
| | | | | | | | | | | |
Collapse
|
14
|
Tansatit T, Sahaphong S, Riengrojpitak S, Viyanant V, Sobhon P. Fasciola gigantica: the in vitro effects of artesunate as compared to triclabendazole on the 3-weeks-old juvenile. Exp Parasitol 2012; 131:8-19. [PMID: 22425749 DOI: 10.1016/j.exppara.2012.02.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 02/11/2012] [Accepted: 02/20/2012] [Indexed: 11/19/2022]
Abstract
The in vitro effect of artesunate (ATS) on the 3-week-old juveniles of Fasciola gigantica was compared with triclabendazole (TCZ) by incubating the parasites in M-199 medium containing the drugs at concentrations of 20, 40, and 80 μg/ml for 1, 3, 6, 12, and 24h. The anthelmintic activities of these drugs were evaluated based on the relative motility value (RM) and the alterations of the tegument as observed by scanning (SEM) and transmission (TEM) electron microscopy. The RM values of TCZ-treated flukes decreased significantly from 6 to 24h for all dosages. For ATS-treated flukes, RM value decreased markedly from 12 to 24h, but the rates of decline were less than TCZ at the same doses. When observed by SEM, the tegument showed similar sequence of morphological changes after treatments with both drugs, comprising of swelling of tegumental ridges, followed by blebbing and later rupturing of the blebs, leading to erosion and lesion, and disruption of the tegument. When examined by TEM, ultrastructural changes in the tegument and associated structures after treatments with TCZ and ATS were similar which comprised of swelling, blebbing of the tegument, dilation of basal infoldings, and depolymerization of the microtrabecular network. After a longer incubation time, the tegument was completely sloughed off and the tegument cell bodies became necrotic. Additionally, in ATS-treated flukes, mitochondria showed severe swelling, rupturing of outer membrane, and their interior filled with flocculent materials.
Collapse
Affiliation(s)
- Tawewan Tansatit
- Department of Preclinic and Applied Animal Science, Faculty of Veterinary Science, Mahidol University, Nakhonpathom 73170, Thailand
| | | | | | | | | |
Collapse
|
15
|
Seif el-Din SH, Al-Hroob AM, Ebeid FA. Schistosoma mansoni: N-acetylcysteine downregulates oxidative stress and enhances the antischistosomal activity of artemether in mice. Exp Parasitol 2011; 128:230-5. [PMID: 21426905 DOI: 10.1016/j.exppara.2011.03.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 03/10/2011] [Accepted: 03/14/2011] [Indexed: 01/17/2023]
Abstract
UNLABELLED Artemether (Art), a derivative of the antimalarial artemisinin, also exhibit antischistosomal properties. N-acetylcysteine (NAC) has a diversity of applications, largely because of the chemical properties of the thiol moiety present in its structure. The ability of this moiety to sweep reactive oxygen species is well-established with NAC. This study investigates the ability of NAC to enhance the therapeutic potential of Art against adult Schistosoma mansoni infection and evaluates the protective role of this antioxidant on S. mansoni-induced oxidative stress. Mice were divided into five groups; normal (i), infected control (ii), infected treated with NAC, 300mg/kg 5 days a week/4weeks (iii), infected treated with Art (300mg/kg) 7 weeks post infection (iv) and infected treated with both NAC and Art (v). Results showed that Art produced a significant reduction in total number of worms when used alone. Also, it decreased hepatic ova count significantly accompanied with an increase in the percentage of dead ova. Treatment with NAC alone increased the percentage of dead ova; meanwhile, it enhanced the decrease in total number of worms and hepatic ova count when used with Art. Infection with S. mansoni significantly increased tissue GSH, GR, SOD and serum ALT and GGT, while decreased the activities of GST, GPx and the levels of proteins and albumin compared to normal control. Treatment with NAC alone approximately recovered the contents of GSH, activities of GPx and levels of serum albumin, ALT and GGT relative to normal control. A tendency for normalization in activities of the antioxidant enzymes mentioned above and serum levels of liver function tests was observed in the groups treated with Art alone or Art+NAC. CONCLUSION NAC downregulates oxidative stress induced by S. mansoni infection and enhances the therapeutic potential of artemether against adult schistosomes.
Collapse
Affiliation(s)
- Sayed H Seif el-Din
- Pharmacology Department, Theodor Bilharz Research Institute, Warak El-Hadar, Imbaba P.O. Box 30, Giza 12411, Egypt.
| | | | | |
Collapse
|
16
|
Electron microscopical study to assess the in vitro effects of the synthetic trioxolane OZ78 against the liver fluke, Fasciola hepatica. Parasitology 2009; 136:1325-37. [PMID: 19660154 DOI: 10.1017/s0031182009990643] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Adult Fasciola hepatica were incubated for 48 h in vitro in the synthetic peroxide, OZ78 at a concentration of 100 microg/ml and then prepared for scanning and transmission electron microscopy. There was limited disruption to the external fluke surface, with only slight swelling and blebbing of the interspinal tegument in the midbody and ventral tail regions. By contrast, significant disruption was observed to the ultrastructure of the tegument and subtegumental tissues. There was severe swelling of the basal infolds in the tegumental syncytium and the flooding spread internally to affect the subtegumental tissues. In the tegumental system, there was swelling of the cisternae of granular endoplasmic reticulum and of the mitochondria, with the latter showing signs of breaking down. Autophagic vacuoles and lipid droplets were present and the synthesis of tegumental secretory bodies was much reduced. The gastrodermal cells were severely affected, with swelling and degeneration of the mitochondria and the presence of autophagic vacuoles and lipid droplets. The granular endoplasmic reticulum was swollen and vesiculated and the cells contained few secretory bodies. Both the vitelline and testis follicles showed evidence of extensive cellular disruption and degeneration. This study confirms previous data indicating the potential flukicidal activity of OZ78.
Collapse
|
17
|
Wang MW, Hao X, Chen K. Biological screening of natural products and drug innovation in China. Philos Trans R Soc Lond B Biol Sci 2007; 362:1093-105. [PMID: 17317643 PMCID: PMC2435573 DOI: 10.1098/rstb.2007.2036] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Natural products have been applied to human healthcare for thousands of years. Drug discovery in ancient times was largely by chance and based on clinical practices. As understanding of therapeutic benefits deepens and demands for natural products increase, previously serendipitous discoveries evolve into active searches for new medicines. Many drugs presently prescribed by physicians are either directly isolated from plants or are artificially modified versions of natural products. Scientists are looking for lead compounds with specific structures and pharmacological effects often from natural sources. Experiences and successes of Chinese scientists in this specialized area have resulted in a number of widely used drugs. The tremendous progress made in life sciences has not only revealed many pathological processes of diseases, but also led to the establishment of various molecular and cellular bioassays in conjunction with high-throughput technologies. This is advantageous and permits certain natural compounds that are difficult to isolate and purify, and compounds that are difficult to synthesize, to be assayed. The transition from traditional to empirical and to molecular screening will certainly increase the probability of discovering new leads and drug candidates from natural products.
Collapse
Affiliation(s)
- Ming-Wei Wang
- The National Centre for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, People's Republic of China.
| | | | | |
Collapse
|
18
|
Xiao SH. Development of antischistosomal drugs in China, with particular consideration to praziquantel and the artemisinins. Acta Trop 2005; 96:153-67. [PMID: 16112072 DOI: 10.1016/j.actatropica.2005.07.010] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Remarkable achievements have been made in the control of schistosomiasis in China, with chemotherapy playing a seminal role. From the early 1950s through the early 1980s, Chinese scientists made considerable progress in discovery and development of compounds with antischistosomal properties, including antimonials, non-antimonials and various effective principles stemming from traditional herbs. However, only few compounds entered clinical testing, while others were abandoned mainly due to their toxicity and poor efficacy. The advent of praziquantel in the 1970s changed the landscape of research and development of drugs for treatment and morbidity control of schistosomiasis. The main Chinese contributions to enhance the understanding of the antischistosomal drug praziquantel are reviewed here, including issues of metabolism, antibody-dependency, host immune factors, stage-specific susceptibility and resistance. Over the past 25 years, researchers from China successfully developed artemether and artesunate, two derivatives from the antimalarial artemisinin, as promising drugs against Schistosoma japonicum. Laboratory investigations showed that the artemisinins display their highest activity against the juvenile stages of the parasite. These findings were consistently confirmed in randomised controlled trials; repeated oral administration of artemether or artesunate was safe and efficacious in the prevention of patent S. japonicum infections. The key findings are reviewed here, and emphasis is placed on how it stimulated research outside of China on other human schistosome species.
Collapse
Affiliation(s)
- Shu-Hua Xiao
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, China.
| |
Collapse
|
19
|
Mahmoud MR, Botros SS. ARTEMETHER AS ADJUVANT THERAPY TO PRAZIQUANTEL IN MURINE EGYPTIAN SCHISTOSOMIASIS MANSONI. J Parasitol 2005; 91:175-8. [PMID: 15856895 DOI: 10.1645/ge-322r] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
We investigated the activity of artemether (ART) against different developmental stages of schistosomes alone and in addition to praziquantel (PZQ). ART was administered orally (400 mg/kg) 4 and 6 wk postinfection (PI), 4 and 5 wk PI, or 4 or 6 wk PI alone and in addition to oral PZQ (500 x 2 mg/kg) 6 wk PI. Mice were killed in parallel to infected untreated controls 8 wk PI. Parasitological parameters and histological changes in the liver were studied. ART given 4 and 6 wk PI reduced worm burdens by 59 and 55% and tissue egg load by 96 and 90%, respectively. Moreover, eggs in different developmental stages were not found. The reduction in worm and egg burden (63 and 58%, and 96 and 99%, respectively) in mice treated with ART 4 and 5 wk or 4 and 6 wk PI was comparable with that in ART-treated mice at 4 or 6 wk PI. Compared with PZQ alone, combined treatment of PZQ and ART (4 and 5 wk or 4 and 6 wk PI) did not enhance worm eradication, but there was a complete absence of parasite eggs. Livers revealed no granulomata when ART was given 4 and 5 wk or 4 and 6 wk PI, with minimal central necrosis in those treated 4 and 6 wk PI. In conclusion, combined treatment of ART (4 and 6 wk PI) and PZQ resulted in >90% worm eradication and amelioration of Schistosoma mansoni eggs from the tissues, with minor histological changes in the liver.
Collapse
Affiliation(s)
- M R Mahmoud
- Pharmacology Department, Theodor Bilharz Research Institute, Giza 12411, Egypt
| | | |
Collapse
|
20
|
Xiao S, Shen B, Utzinger J, Chollet J, Tanner M. Ultrastructural alterations in adult Schistosoma mansoni caused by artemether. Mem Inst Oswaldo Cruz 2002; 97:717-24. [PMID: 12219141 DOI: 10.1590/s0074-02762002000500023] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Progress has been made over the last decade with the development and clinical use of artemether as an agent against major human schistosome parasites. The tegument has been identified as a key target of artemether, implying detailed studies on ultrastructural damage induced by this compound. We performed a temporal examination, employing a transmission electron microscope to assess the pattern and extent of ultrastructural alterations in adult Schistosoma mansoni harboured in mice treated with a single dose of 400 mg/kg artemether. Eight hours post-treatment, damage to the tegument and subtegumental structures was seen. Tegumental alterations reached a peak 3 days after treatment and were characterized by swelling, fusion of distal cytoplasma, focal lysis of the tegumental matrix and vacuolisation. Tubercles and sensory organelles frequently degenerated or collapsed. Typical features of subtegumental alterations, including muscle fibres, syncytium and parenchyma tissues, were focal or extensive lysis, vacuolisation and degeneration of mitochondria. Severe alterations were also observed in gut epithelial cells and vitelline cells of female worms. Our findings of artemether-induced ultrastructural alterations in adult S. mansoni confirm previous results obtained with juvenile S. mansoni and S. japonicum of different ages.
Collapse
Affiliation(s)
- Shuhua Xiao
- Institute of Parasitic Diseases, Chinese Academy of Preventive Medicine, Shanghai, China
| | | | | | | | | |
Collapse
|