Resveratrol protects against Schistosoma mansoni-induced liver fibrosis by targeting the Sirt-1/NF-κB axis.

Hepatic schistosomiasis is a prevalent form of chronic liver disease that drastically affects human health. Nevertheless, an antifibrotic drug that could suppress the development of hepatic fibrosis does not exist yet. The current study aimed to evaluate the effect of resveratrol, a natural polyphenol with multiple biological activities, on Schistosoma mansoni (S. mansoni)-induced hepatic fibrosis and delineate the underlying molecular mechanism. Swiss male albino mice were randomly assigned into infected and non-infected groups. Hepatic schistosomiasis infection was induced via exposure to S. mansoni cercariae. 6 weeks later, resveratrol was administrated either as 20 mg/kg/day or 100 mg/kg/day for 4 weeks to two infected groups. Another group received vehicle and served as infected control group. At the end of the study, portal hemodynamic, biochemical, and histopathological evaluation of liver tissues were conducted. Remarkably, resveratrol significantly reduced portal pressure, portal and mesenteric flow in a dose-dependent manner. It improved several key features of hepatic injury as evidenced biochemically by a significant reduction of bilirubin and liver enzymes, and histologically by amelioration of the granulomatous and inflammatory reactions. In line, resveratrol reduced the expression of pro-inflammatory markers; TNF-α, IL-1ß and MCP-1 mRNA, together with fibrotic markers; collagen-1, TGF-ß1 and α-SMA. Moreover, resveratrol restored SIRT1/NF-κB balance in hepatic tissues which is the main switch-off control for all the fibrotic and inflammatory mechanisms. Taken together, it can be inferred that resveratrol possesses a possible anti-fibrotic effect that can halt the progression of hepatic schistosomiasis via targeting SIRT1/ NF-κB signaling.

Shedding light on a mysterious link between Toxoplasma gondii and cancer: A review.

The ongoing conflict regarding the affiliation of Toxoplasma gondii to cancer; whether an inducer or a suppressor needs to be resolved. Human epidemiological studies oscillate without attaining a firm ground. Some studies confirmed the detection of high seroprevalence of anti-Toxoplasma antibodies in different cancer patients without further justification whether being causation, co-incidences, or part of opportunistic infections. Others reported a state of resistance to cancer accompanying low titer of anti-Toxoplasma antibody. Worthwhile, preclinical experimental work confirmed the antineoplastic potency of Toxoplasma. Thus, further investigational research is essential to validate the potential application of Toxoplasma as a promising cancer immunotherapeutic vaccine candidate. In this paper, we present a review of this issue by examining epidemiological and preclinical experimental studies that explored the linkage between Toxoplasma gondii and cancer. We consider this review an important step towards shedding a light on this mysterious link and a stepping-stone for potential research work addressing Toxoplasma as a cancer suppressor rather than a cancer inducer.

Prophylactic antineoplastic activity of Toxoplasma gondii RH derived antigen against ehrlich solid carcinoma with evidence of shared antigens by comparative immunoblotting.

BACKGROUND: With cancer cases escalation, an urgent request to develop novel combating strategies arise. Pathogen-based cancer-immunotherapy is getting more consideration. Autoclaved parasitic antigens seem promising candidates, taking steadily their first steps. Our aim was to examine the prophylactic antineoplastic activity of autoclaved Toxoplasma vaccine (ATV) and to test for the shared antigen theory between Toxoplasma gondii and cancer cells. METHODS: Mice were immunized with ATV followed by Ehrlich solid carcinoma (ESC) inoculation. Tumor weight, volume, histopathology, and immunohistochemistry for CD8+ T cells, Treg cells and VEGF were assessed. In addition, the proposed shared antigen theory between parasites and cancer was also verified using SDS-PAGE and immunoblotting. RESULTS: Results revealed powerful prophylactic activity of ATV with 13.3% inhibition of ESC incidence, significant reduction in tumor weight and volume in ATV vaccinated mice. Immunologically, significantly higher CD8+T cells and lower FOXP3+ Treg cells surrounded and infiltrated ESC in ATV immunized mice with higher CD8+T/Treg cells ratio and significant antiangiogenic effect. Moreover, SDS-PAGE and immunoblotting showed four shared bands between Ehrlich carcinoma and ATV of approximate molecular weights 60, 26, 22 and 12.5 KDa. CONCLUSION: Exclusively, we demonstrated a prophylactic antineoplastic activity of autoclaved Toxoplasma vaccine against ESC. Moreover, to the best of our knowledge this is the first report highlighting the existence of cross-reactive antigens between Toxoplasma gondi parasite and cancer cells of Ehrlich carcinoma.

Toxoplasma gondii-derived antigen modifies tumor microenvironment of Ehrlich solid carcinoma murine model and enhances immunotherapeutic activity of cyclophosphamide.

Pathogen-based cancer vaccine is a promising immunotherapeutic weapon to stimulate cancer immunosuppressive state. Toxoplasma gondii is a potent immunostimulant, and low-dose infection was linked to cancer resistance. Our goal was to evaluate the therapeutic antineoplastic activity of autoclaved Toxoplasma vaccine (ATV) against Ehrlich solid carcinoma (ESC) in mice in reference to and in combination with low-dose cyclophosphamide (CP), a cancer immunomodulator. Mice inoculation with ESC was followed by applying different treatment modalities including ATV, CP, and CP/ATV. We evaluated the impact of the different treatments on liver enzymes and pathology, tumor weight, volume, and histopathological changes. Using immunohistochemistry, we evaluated CD8+ T cell, FOXP3+ Treg, CD8+/Treg outside and inside ESC, and angiogenesis. Results showed significant tumor weights and volumes reduction with all treatments with 13.3% inhibition of tumor development upon combined CP/ATV use. Significant necrosis and fibrosis were noted in ESC by all treatments with improved hepatic functions versus non-treated control. Although ATV was almost equivalent to CP in tumor gross and histopathology, it promoted an immunostimulatory activity with significant Treg cells depletion outside ESC and CD8+ T cells infiltration inside ESC with higher CD8+ T/Treg ratio inside ESC superior to CP. Combined with CP, ATV exhibited significant synergistic immunotherapeutic and antiangiogenic action compared to either treatment alone with significant Kupffer cells hyperplasia and hypertrophy. Exclusively, therapeutic antineoplastic and antiangiogenic activity of ATV against ESC was verified that boosted CP immunomodulatory action which highlights a novel biological cancer immunotherapeutic vaccine candidate.

Single oral fixed-dose praziquantel-miltefosine nanocombination for effective control of experimental schistosomiasis mansoni.

BACKGROUND: The control of schistosomiasis has been centered to date on a single drug, praziquantel, with shortcomings including treatment failure, reinfection, and emergence of drug resistance. Drug repurposing, combination therapy or nanotechnology were explored to improve antischistosomal treatment. The aim of the present study was to utilize a novel combination of the three strategies to improve the therapeutic profile of praziquantel. This was based on a fixed-dose nanocombination of praziquantel and miltefosine, an antischistosomal repurposing candidate, co-loaded at reduced doses into lipid nanocapsules, for single dose oral therapy. METHODS: Two nanocombinations were prepared to provide 250 mg praziquantel-20 mg miltefosine/kg (higher fixed-dose) or 125 mg praziquantel-10 mg miltefosine/kg (lower fixed-dose), respectively. Their antischistosomal efficacy in comparison with a non-treated control and their praziquantel or miltefosine singly loaded counterparts was assessed in murine schistosomiasis mansoni. A single oral dose of either formulation was administered on the initial day of infection, and on days 21 and 42 post-infection. Scanning electron microscopic, parasitological, and histopathological studies were used for assessment. Preclinical data were subjected to analysis of variance and Tukey's post-hoc test for pairwise comparisons. RESULTS: Lipid nanocapsules (~ 58 nm) showed high entrapment efficiency of both drugs (> 97%). Compared to singly loaded praziquantel-lipid nanocapsules, the higher nanocombination dose showed a significant increase in antischistosomal efficacy in terms of statistically significant decrease in mean worm burden, particularly against invasive and juvenile worms, and amelioration of hepatic granulomas (P ≤ 0.05). In addition, scanning electron microscopy examination showed extensive dorsal tegumental damage with noticeable deposition of nanostructures. CONCLUSIONS: The therapeutic profile of praziquantel could be improved by a novel multiple approach integrating drug repurposing, combination therapy and nanotechnology. Multistage activity and amelioration of liver pathology could be achieved by a new praziquantel-miltefosine fixed-dose nanocombination providing 250 mg praziquantel-20 mg miltefosine/kg. To the best of our knowledge, this is the first report of a fixed-dose nano-based combinatorial therapy for schistosomiasis mansoni. Further studies are needed to document the nanocombination safety and explore its prophylactic activity and potential to hinder the onset of resistance to the drug components.

Evaluation of prophylactic efficacy and safety of praziquantel-miltefosine nanocombination in experimental Schistosomiasis mansoni.

The control of schistosomiasis depends exclusively on praziquantel (PZQ) monotherapy with treatment failure due to minor activity against the juvenile stage, re-infection and emerging drug resistance. Improving the antischistosomal therapeutic/prophylactic profile of PZQ is a sensible option to save the clinical benefits of the drug if achieved effectively and safely via a single oral dose. Recently, we developed praziquantel-miltefosine lipid nanocapsules (PZQ 250 mg/kg-MFS 20 mg/kg LNCs) as a nanotechnology-enabled novel drug combination with significant multistage activity against Schistosoma mansoni (S. mansoni) in a murine model. The present study aimed at providing a proof of concept of the chemoprophylactic effect of this nanocombination. A single oral dose of the nanocombination was administered to mice one and seven days before challenge infection with S. mansoni. The protective effect of the nanocombination was assessed parasitologically and histopathologically relative to LNCs singly-loaded with PZQ or MFS and non-treated infected controls. In addition, the safety of the nanocombination was assessed biochemically and histopathologically. Administration of the nanocombination one or seven days pre-infection resulted in a statistically significant reduction in mean worm burden and granulomas size associated with amelioration of hepatic pathology compared to infected non-treated control. Although, the prophylactic effect was significantly reduced upon administration seven days pre-infection compared to administration one day pre-infection, yet, it still exists. Results were explained based on the spectrum of activity of PZQ and MFS and their complementary pharmacokinetic (PK) profiles in addition to the effect of nanoencapsulation on these factors. The novel PZQ-MFS nanocombination offers valuable potentials in PZQ-based mass drug administration programmes by granting radical cure, preventing re-infection, and delaying development of resistance to the component drugs.

Immuno-therapeutic potential of Schistosoma mansoni and Trichinella spiralis antigens in a murine model of colon cancer.

Considerable evidence indicates a negative correlation between the prevalence of some parasitic infections and cancer and their interference with tumor growth. Therefore, parasitic antigens seem to be promising candidates for cancer immunotherapy. In this study, the therapeutic efficacy of autoclaved Schistosoma mansoni and Trichinella spiralis antigens against a colon cancer murine model was investigated. Both antigens showed immunomodulatory potential, as evidenced by a significant decrease in serum IL-17, a significant increase in serum IL-10, and the percentage of splenic CD4+T-cells and intestinal FoxP3+ Treg cells. However, treatment with S. mansoni antigen yielded protection against the deleterious effect of DMH-induced colon carcinogenesis only, with a significant decrease in the average lesion size and number of neoplasias per mouse. For the first time, we report an inhibitory effect of S. mansoni antigen on the progression of chemically induced colon carcinogenesis, but the exact mechanism has yet to be clarified. This anti-tumor strategy could introduce a new era of medicine in which a generation of anticancer vaccines of parasitic origin would boost the therapy for incurable cancers.

Praziquantel-lipid nanocapsules: an oral nanotherapeutic with potential Schistosoma mansoni tegumental targeting.

PURPOSE: Lipid nanocapsules (LNCs) have shown potential to increase the bioavailability and efficacy of orally administered drugs. However, their intestinal translocation to distal target sites and their implication in pharmacokinetic (PK)-pharmacodynamic (PD) relationships are yet to be elucidated. In this study, the effect of LNCs on the PD activity and pharmacokinetics of praziquantel (PZQ), the mainstay of schistosomiasis chemotherapy, was investigated. MATERIALS AND METHODS: The composition of LNCs was modified to increase PZQ payload and to enhance membrane permeability. PZQ-LNCs were characterized in vitro for colloidal properties, entrapment efficiency (EE%), and drug release. PD activity of the test formulations was assessed in Schistosoma mansoni-infected mice 7 days post-oral administration of a single 250 mg/kg oral dose. Pharmacokinetics of the test formulations and their stability in simulated gastrointestinal (GI) fluids were investigated to substantiate in vivo data. RESULTS: PZQ-LNCs exhibited good pharmaceutical attributes in terms of size (46-62 nm), polydispersity index (0.01-0.08), EE% (>95%), and sustained release profiles. Results indicated significant efficacy enhancement by reduction in worm burden, amelioration of liver pathology, and extensive damage to the fluke suckers and tegument. This was partly explained by PK data determined in rats. In addition, oral targeting of the worms was supported by the stability of PZQ-LNCs in simulated GI fluids and scanning electron microscopy (SEM) visualization of nanostructures on the tegument of worms recovered from mesenteric/hepatic veins. Cytotoxicity data indicated tolerability of PZQ-LNCs. CONCLUSION: Data obtained provide evidence for the ability of oral LNCs to target distal post-absorption sites, leading to enhanced drug efficacy. From a practical standpoint, PZQ-LNCs could be suggested as a potential tolerable single lower dose oral nanomedicine for more effective PZQ mass chemotherapy.

Treatment of Schistosoma mansoni with miltefosine in vitro enhances serological recognition of defined worm surface antigens.

BACKGROUND: Miltefosine, an anti-cancer drug that has been successfully repositioned for treatment of Leishmania infections, has recently also shown promising effects against Schistosoma spp targeting all life cycle stages of the parasite. The current study examined the effect of treating Schistosoma mansoni adult worms with miltefosine on exposure of worm surface antigens in vitro. METHODOLOGY/PRINCIPAL FINDINGS: In an indirect immunofluorescence assay, rabbit anti-S.mansoni adult worm homogenate and anti-S. mansoni infection antisera gave strong immunofluorescence of the S. mansoni adult worm surface after treatment with miltefosine, the latter antiserum having previously been shown to synergistically enhance the schistosomicidal activity of praziquantel. Rabbit antibodies that recognised surface antigens exposed on miltefosine-treated worms were recovered by elution off the worm surface in low pH buffer and were used in a western immunoblotting assay to identify antigenic targets in a homogenate extract of adult worms (SmWH). Four proteins reacting with the antibodies in immunoblots were purified and proteomic analysis (MS/MS) combined with specific immunoblotting indicated they were the S. mansoni proteins: fructose-1,6 bisphosphate aldolase (SmFBPA), Sm22.6, alkaline phosphatase and malate dehydrogenase. These antibodies were also found to bind to the surface of 3-hour schistosomula and induce immune agglutination of the parasites, suggesting they may have a role in immune protection. CONCLUSION/SIGNIFICANCE: This study reveals a novel mode of action of miltefosine as an anti-schistosome agent. The immune-dependent hypothesis we investigated has previously been lent credence with praziquantel (PZQ), whereby treatment unmasks parasite surface antigens not normally exposed to the host during infection. Antigens involved in this molecular mechanism could have potential as intervention targets and antibodies against these antigens may act to increase the drug's anti-parasite efficacy and be involved in the development of resistance to re-infection.

Repositioning of chlorambucil as a potential anti-schistosomal agent.

As parasites and cancer cells share many lifestyle and behavioral resemblances, repositioning of anti-cancerous agents as anti-parasitic is quite trendy, especially those sharing the same therapeutic targets. Therefore, the current study investigated the in vitro efficacy of ascending concentrations of chlorambucil (0.5-20µg/ml) against adult Schistosoma mansoni worms, over 72h. Additionally, its in vivo effects against the different developmental stages of the worm were assessed, after an oral dose of 2.5mg/kg/day for five successive days, through evaluating the worm load reduction and worms' morphological alterations and oogram changes. In addition to tissue egg count, a histopathological study of the liver was conducted. In vitro, chlorambucil demonstrated noticeable anti-schistosomal effects in the form of progressive reductions of the worms' viability in a dose dependent manner. Complete worm death was achieved at 72h incubation with 5µg/ml drug concentration. In vivo, chlorambucil induced a significant reduction in the total worm load against all developmental stages. Its highest impact was evident against the juvenile stage, where it induced 75.8% total worm load reduction, and 89.2% and 86.7% intestinal and hepatic egg counts reduction, respectively, along with ogram alterations. Besides, it induced significant shortening of both male and female worms and promoted an amelioration of hepatic histopathology. Results show that chlorambucil possesses favorable in vitro and in vivo anti-schistosomal activity. The highest in vivo efficacy was against the juvenile stage of S. mansoni, significantly superior to praziquantel, with extended potency to the adult stage. Further studies are recommended for chlorambucil target verification and to enhance its therapeutic efficacy.

Sodium valproate, a histone deacetylase inhibitor, with praziquantel ameliorates Schistosoma mansoni-induced liver fibrosis in mice.

AIMS: This study explores the potential antifibrotic effect of sodium valproate (SV), an inhibitor of class I histone deacetylase (HDAC) enzymes, and/or praziquantel (PZQ) on Schistosoma mansoni (S. mansoni)-induced liver fibrosis in mice. MAIN METHODS: Male Swiss albino mice were divided into nine groups: group I- normal control (NC); group II- uninfected gum mucilage (GM) treated; group III- uninfected PZQ- treated; group IV- uninfected SV-treated; group V- control S. mansoni infected mice; group VI- infected GM-treated; group VII- infected PZQ-treated; group VIII- infected SV-treated; group IX- infected PZQ+SV treated. All SV administrations were 300mg/kg/day orally and administered for five weeks beginning on the 5th week post infection (WPI). All PZQ administrations were 500mg/kg/day orally and administered for 2 consecutive days beginning on the 7th WPI. Serum transforming growth factor-beta 1 (TGF-ß1), tumor necrosis factor-alpha (TNF-α), hepatic hydroxyproline (Hyp) content, and liver function tests (AST and ALT) were determined. Specimens of the hepatic tissues were examined histologically. KEY FINDINGS: Treatment of S. mansoni-infected mice with SV significantly decreased the serum levels of ALT, TGF-ß1 and TNF-α, and the liver tissue hydroxyproline content compared with the S. mansoni infected untreated groups. Histologically, treatment with SV revealed regression of the granulomatous inflammatory reaction. Combined treatment with PZQ and SV produces more favorable biochemical results, and aborted granulomatous reaction compared with either drug alone. SIGNIFICANCE: Sodium valproate is a promising anti-fibrotic agent. It demonstrated an anti-fibrotic effect in early stages of S. mansoni infection through downregulation of profibrogenic cytokines, and collagen deposition.

Miltefosine lipid nanocapsules: Intersection of drug repurposing and nanotechnology for single dose oral treatment of pre-patent schistosomiasis mansoni.

A dual drug repurposing/nanotechnological approach was used to develop an alternative oral treatment for schistosomiasis mansoni using miltefosine (MFS), an anticancer alkylphosphocholine, and lipid nanocapsules (LNCs) as oral nanovectors. We demonstrated earlier that MFS possesses significant activity against different developmental stages of Schistosoma mansoni in the mouse model using 5 successive 20mg/kg/day oral doses. Moreover, an effective single dose (20mg/kg) oral treatment against the adult stage of S. mansoni in mice was developed using LNCs, particularly modified with CTAB, a positive charge imparting agent (MFS-LNC-CTAB(+)), or oleic acid as membrane permeabilizer (MFS-LNC-OA). Efficacy enhancement involved, at least in part, targeting of the worm tegument with MFS-LNCs as a new therapeutic entity. As the tegument surface charge and composition may differ in pre-patent stages of the parasite, it was of importance in the present study to assess the efficacy of a single oral dose of the two MFS-LNC formulations against invasive and immature stages for potential advantage relative to praziquantel. Results indicated potent schistosomicidal effects against both invasive and immature stages of S. mansoni in infected mice, efficacy being both formulation and developmental stage dependent. This was indicated by the significant reduction in the total worm burden of the invasive stage by 91.6% and 76.8% and the immature stage by 82.7% and 96.7% for MFS-LNC-CTAB+ and MFS-LNC-OA, respectively. Histopathological findings indicated amelioration of hepatic pathology with regression of the granulomatous inflammatory reaction and reduction in granulomas number and size, verifying marked improvement in architecture of hepatic lobules. From a clinical perspective, MFS-LNCs offer potential as an alternative single oral dose nanomedicine with a wide therapeutic profile for the mass chemotherapy of schistosomiasis mansoni.

Miltefosine Lipid Nanocapsules for Single Dose Oral Treatment of Schistosomiasis Mansoni: A Preclinical Study.

Miltefosine (MFS) is an alkylphosphocholine used for the local treatment of cutaneous metastases of breast cancer and oral therapy of visceral leishmaniasis. Recently, the drug was reported in in vitro and preclinical studies to exert significant activity against different developmental stages of schistosomiasis mansoni, a widespread chronic neglected tropical disease (NTD). This justified MFS repurposing as a potential antischistosomal drug. However, five consecutive daily 20 mg/kg doses were needed for the treatment of schistosomiasis mansoni in mice. The present study aims at enhancing MFS efficacy to allow for a single 20mg/kg oral dose therapy using a nanotechnological approach based on lipid nanocapsules (LNCs) as oral nanovectors. MFS was incorporated in LNCs both as membrane-active structural alkylphospholipid component and active antischistosomal agent. MFS-LNC formulations showed high entrapment efficiency (EE%), good colloidal properties, sustained release pattern and physical stability. Further, LNCs generally decreased MFS-induced erythrocyte hemolytic activity used as surrogate indicator of membrane activity. While MFS-free LNCs exerted no antischistosomal effect, statistically significant enhancement was observed with all MFS-LNC formulations. A maximum effect was achieved with MFS-LNCs incorporating CTAB as positive charge imparting agent or oleic acid as membrane permeabilizer. Reduction of worm load, ameliorated liver pathology and extensive damage of the worm tegument provided evidence for formulation-related efficacy enhancement. Non-compartmental analysis of pharmacokinetic data obtained in rats indicated independence of antischistosomal activity on systemic drug exposure, suggesting possible gut uptake of the stable LNCs and targeting of the fluke tegument which was verified by SEM. The study findings put forward MFS-LNCs as unique oral nanovectors combining the bioactivity of MFS and biopharmaceutical advantages of LNCs, allowing targeting via the oral route. From a clinical point of view, data suggest MFS-LNCs as a potential single dose oral nanomedicine for enhanced therapy of schistosomiasis mansoni and possibly other diseases.

Could miltefosine be used as a therapy for toxoplasmosis?

Toxoplasmosis is a zoonotic protozoal disease affecting more than a billion people worldwide. The shortfalls of the current treatment options necessitate the development of non-toxic and well-tolerated, efficient alternatives especially against the cyst form. The current study was undertaken to investigate, for the first time, the potential potency of miltefosine against Toxoplasma gondii infection in acute and chronic experimental toxoplasmosis. Results showed that there is no evidence of anti-parasitic activity of miltefosine against T. gondii tachyzoites in acute experimental toxoplasmosis. However, anti-parasitic activity of miltefosine against T. gondii cyst stage in chronic experimental toxoplasmosis could not be excluded as demonstrated by significant reduction in brain cyst burden. Moreover, considerable morphological changes in the cysts were revealed by light and electron microscopy study and also by amelioration of pathological changes in the brain. Future studies should focus on enhancement of anti-toxoplasma activity of miltefosine against chronic toxoplasmosis using formulation based nanotechnology. To the best of our knowledge, this is the first study highlighting efficacy of miltefosine against chronic toxoplasmosis, thus, increasing the list of diseases that can be targeted by this drug.

Initial characterization of an autoclaved Toxoplasma vaccine in mice.

Toxoplasmosis is a zoonotic protozoal disease that has a major significance from the perspectives of public health and veterinary medicine. Therefore, an obvious long-term goal of many scientists would be the development of an effective vaccine. In this study, autoclaved vaccine was evaluated for its ability to protect mice against Toxoplasma gondii RH challenge as an acute infection model. Results showed that autoclaved Toxoplasma vaccine (ATV) when combined with BCG as an adjuvant was effective in triggering cell mediated immunity as shown by a significant increase in the percentage of splenic CD8+ T-lymphocytes. Following challenge, death of mice vaccinated with ATV was delayed for nine days. There was a significant decrease in parasite density in different organs, and a marked reduction of pathological changes in the liver suggesting that significant immune responses were mounted following vaccination. Future studies are warranted to test the vaccine against challenge with brain cysts as a chronic infection model and to evaluate it with other recent immunization strategies that can further enhance its immunogenicity.

Leishmania major: activity of tamoxifen against experimental cutaneous leishmaniasis.

Leishmaniasis is a family of diseases caused by protozoan parasites of the genus Leishmania. Various Leishmania species can cause human infection, producing a spectrum of clinical manifestations. The current treatments are unsatisfactory, and in absence of a vaccine, there is an urgent need for effective drugs to replace/supplement those currently in use. Recent studies have shown that the antineoplastic drug, tamoxifen, had direct leishmanicidal effect on several Leishmania species in vitro. Moreover, in vivo testing was carried out on some of the species and showed promising results. The authors have carried out the present work to complement previous published studies by investigating in vivo activity of tamoxifen in an experimental model of cutaneous leishmaniasis (CL) caused by Leishmania major. Groups of infected mice were given tamoxifen, orally, at a dose of 20 mg/kg/day for 15 days. Efficacy was assessed clinically, parasitologically, histopathologically by light and transmission electron microscope (TEM). Results showed that untreated infected mice suffered from autoamputation of the inoculated foot pad. However, those which received tamoxifen showed marked improvement of the cutaneous lesions and reduction of parasite burden. TEM of the cutaneous lesions from infected mice revealed the fine structure of normal Leishmania amastigotes, whereas those from infected mice treated with tamoxifen showed considerable changes. All male mice that received tamoxifen showed scrotal swelling with evident histopathological changes in the testes that could seriously compromise fertility of male mice. In conclusion, although tamoxifen causes significant side effects to the male reproductive system in the mouse model, it could provide an alternative to current agents. Results of this study demonstrated in vivo activity of tamoxifen against Leishmania major, thus, suggesting that tamoxifen is a suitable lead for the synthesis of more effective and less toxic antileishmanial derivatives.

Miltefosine, a promising novel agent for schistosomiasis mansoni.

This research aims towards developing an alternative antischistosomal drug using miltefosine, which is primarily used in the treatment of leishmaniasis. The treatment and control of schistosomiasis, a notable neglected tropical disease (NTD), rely on a single drug, praziquantel (PZQ). The dependency on PZQ exclusively is quite alarming, given the spread of the disease (over 200 million people infected and close to 800 million people at risk in three continents) and the threat of drug resistance. This study shows that the oral administration of miltefosine in a daily dose of 20mg/kg for five successive days to mice infected with either invasive, juvenile or adult stages of Schistosoma mansoni resulted in significant reduction of worm burden, hepatic granulomata size and amelioration of hepatic pathology. Scanning Electron Microscopy revealed that miltefosine induced severe tegumental damage in adult schistosomes. In conclusion, we believe this is the first study highlighting miltefosine as a promising novel agent for schistosomiasis mansoni.

Inheritance of Schistosoma mansoni infection incompatibility in Biomphalaria alexandrina snails

In this study, we looked at the inheritance of susceptibility and resistance to Schistosoma mansoni infection in the first generation of crossbred Biomphalaria alexandrina snails. Our ultimate goal is to use such information to develop a biological method of controlling schistosomiasis. We infected laboratory-bred snails with S. mansoni miracidia and examined cercarial shedding to determine susceptibility and resistance. Five parental groups were used: Group I contained 30 susceptible snails, Group II contained 30 resistant snails, Group III contained 15 susceptible and 15 resistant snails, Group IV contained 27 susceptible and three resistant snails and Group V contained three susceptible and 27 resistant snails. The percentage of resistant snails in the resulting progeny varied according to the ratio of susceptible and resistant parents per group; they are 7 percent, 100 percent, 68 percent, 45 percent and 97 percent from Groups I, II, III, IV and V, respectively. On increasing the percentage of resistant parent snails, the percentage of resistant progeny increased, while cercarial production in their susceptible progeny decreased.

Vaccination trial against experimental trichrinellosis using autoclaved Trichinella spiralis larvae vaccine (ATSLV).

The autoclaved Trichinella spiralis larvae vaccine (ATSLV) was tested and showed a surprising and somewhat unpredictable effect on the immune system of mice experimentally infected with T. spiralis. The vaccine was given with Bacille Calmette Guerin (BCG) as an adjuvant at different durations and by different routes of administration. The best result was achieved by given the vaccine twice intradermally with two weeks interval, as evidenced by a significant reduction in adult and larval count, as well as reproductive capacity index. Histopathologically, there was significant reduction in number of the encysted larvae which showed degeneration and hyalinization of the cyst wall accompanied by early pericystic fibrosis.

Ultrastructural and immunological features of experimental cutaneous leishmaniasis after treatment with intralesional hypertonic sodium chloride and CO2 laser rays.

This study investigated the mechanism of action and efficacy of CO2 laser rays and hypertonic sodium chloride (NaCl) with different concentrations in treatment of cutaneous leishmaniasis (CL) as assessed clinically, parasitologically, histopathologically by light & transmission electron microscopy (TEM) and immunologically by RT-PCR for gene expression of interleukin-13 (IL-13). Eighty mice were divided into four groups. The first was non infected control group (n=16) and the second was infected and served as non-treated control (n=16). The third (n=32) and fourth groups (n=16) were subjected to NaCl injection and CO2 laser respectively. Results showed that clinical healing by CO2 laser were nearly similar to normal appearance, but differed according to concentration of NaCl, as confirmed by ultrastructure and immunohistopathologic features of the host cells and surrounding skin tissue. IL-13 mRNA was significantly decreased after treatment denoting that Th2 cytokine (IL-13) is important for the development of strategies to prevent the induction of pathologic processes. It is concluded that CO2 laser then 7% NaCl are good modalities for CL treatment and is recommended wherever possible.