The use of pentoxifylline as adjuvant therapy with praziquantel downregulates profibrogenic cytokines, collagen deposition and oxidative stress in experimental schistosomiasis mansoni

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-1β and MCP-1 mRNA, together with fibrotic markers; collagen-1, TGF-β1 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.

Effects of Dexamethasone and Pentoxifylline on Mania-like and Depression-like Behaviors in Rats

Several studies support the notion that inflammation plays a role in the pathophysiology and treatment approaches of psychiatric illnesses, particularly mood disorders. Congruently, classic anti-inflammatory drugs were found efficacious in randomized clinical trials of patients with mood disorders. Moreover, accumulating data indicate that psychotropic drugs exhibit some anti-inflammatory effects. This study was undertaken to examine the efficacy of dexamethasone (a potent corticosteroid) and pentoxifylline (a methylxanthine drug with proven anti-tumor necrosis factor-α inhibitory activity) in behavioral models in rats, which were treated intraperitoneally with either dexamethasone or pentoxifylline for two weeks and then subjected to a battery of behavioral tests. Treatment with pentoxifylline, but not dexamethasone, was associated with antidepressant-like and anti-manic-like effects. The beneficial behavioral effects of pentoxifylline were accompanied by a prominent reduction in pro-inflammatory mediator levels in the brain. For the first time, the current work proves the efficacy of pentoxifylline against both mania-like and depressive-like behaviors. These results suggest that pentoxifylline may be a promising therapeutic intervention for patients with mood disorders. Taking into account the excellent tolerability profile of pentoxifylline in humans, it is warranted to conduct randomized clinical trials to investigate its therapeutic efficacy in patients with psychiatric disorders.

Itraconazole, a cytochrome P450 inhibitor, enhanced the efficacy of praziquantel against Schistosoma mansoni infection and alleviated liver injury in mice

Treatment of schistosomiasis is heavily reliant on the single antischistosomal drug praziquantel (PZQ). The use of synergistic drug-drug interactions is one possible solution, which could be used to mitigate PZQ's poor and variable bioavailability. Itraconazole (ITZ), a triazole antifungal agent, is a potent CYP3A inhibitor that can cause significant drug-drug interactions when used with CYP3A substrates. This study investigates the effect of ITZ as adjuvant therapy with PZQ on worm load, egg deposition and maturation, and the consequent histopathology and biochemical abnormalities in the liver during the immature and mature stages of Schistosoma mansoni (S. mansoni) infection. S. mansoni-infected mice were divided into five groups of eight-ten mice each: (I) infected untreated, (II) infected and treated with PZQ 3 weeks PI, (III) infected and treated with both ITZ and PZQ 3 weeks PI, (IV) infected and treated with PZQ 7 weeks PI, and (V) infected and treated with both ITZ and PZQ 7 weeks PI. All mice were killed by rapid decapitation 9 weeks PI. Data revealed that ITZ in combination with PZQ at both immature and mature stages improved the parasitological criteria of cure, and greatly reduced inflammation, granuloma and fibrotic tissue formation, and apoptosis versus PZQ alone. Furthermore, it showed the greatest impact on improving liver injury and oxidative stress markers. Notably, the effect was considerably stronger at the mature stage of S. mansoni infection. These findings support the notion that ITZ increased PZQ's antischistosomal activity by inhibiting CYP450 expression, potentially reducing PZQ metabolism and increasing systemic exposure.

Pentoxifylline as a Potential Adjuvant Therapy for COVID-19: Impeding the Burden of the Cytokine Storm

The outburst of inflammatory response and hypercoagulability are among the factors contributing to increased mortality in severe COVID-19 cases. Pentoxifylline (PTX), a xanthine-derived drug registered for the treatment of vascular claudication, has been reported to display broad-spectrum anti-inflammatory and immunomodulatory properties via adenosine A2A receptor (A2AR)-related mechanisms, in parallel to its rheological actions. Prior studies have indicated the efficacy of PTX in the treatment of various pulmonary diseases, including the management of acute respiratory distress syndrome of infectious causes. Therefore, PTX has been proposed to have potential benefits in the treatment of SARS-CoV-2 symptoms, as well as its complications. The aim of this review is to discuss available knowledge regarding the role of PTX as a complementary therapeutic in SARS-CoV-2.

Anti-TNF-α Compounds as a Treatment for Depression

Millions of people around the world suffer from psychiatric illnesses, causing unbearable burden and immense distress to patients and their families. Accumulating evidence suggests that inflammation may contribute to the pathophysiology of psychiatric disorders such as major depression and bipolar disorder. Copious studies have consistently shown that patients with mood disorders have increased levels of plasma tumor necrosis factor (TNF)-α. Given these findings, selective anti-TNF-α compounds were tested as a potential therapeutic strategy for mood disorders. This mini-review summarizes the results of studies that examined the mood-modulating effects of anti-TNF-α drugs.

Doxycycline aggravates granulomatous inflammation and lung microstructural remodeling induced by Schistosoma mansoni infection

Although doxycycline exhibits immunomodulatory properties, its effects on pulmonary infection by Schistosoma mansoni remain overlooked. Thus, we investigated the impact of this drug on lung granulomatous inflammation and microstructural remodeling in a murine model of schistosomiasis. Swiss mice were randomized in four groups: (i) uninfected, (ii) infected with S. mansoni and untreated, (iii) infected treated with praziquantel (Pzq; 200 mg/kg), and (iv) infected treated with Dox (50 mg/kg). Pz was administered in a single dose, and Dox for 60 days. S. mansoni induced marked granulomatous lung inflammation, which was associated to cytokines upregulation (IL-2, IL-4, IL-10, IFN-γ, TNF-α, and TGF-β), neutrophils and macrophages recruitment, alveolar collapse, lung fibrosis, and extensive depletion of elastic fibers. These parameters were attenuated by Pzq and aggravated by Dox. Exudative/productive granulomas were predominant in untreated and Dox-treated animals, while fibrotic granulomas were more frequent in Pzq-treated mice. The number and size of granulomas in Dox-treated animals was higher than untreated and Pzq-treated mice. Dox treatment inhibited the increase in MMP-1 and MMP-2 activity but upregulated myeloperoxidase and N-acetylglucosaminidase activity compared to untreated and Pzq-treated animals. Dox and Pzq exerted no effect on elastin depletion and upregulation of elastase activity. Together, our findings indicated that Dox aggravated granulomatous inflammation, accelerating lung microstructural remodeling by downregulating MMP-1 and MMP-2 activity without impair neutrophils and macrophages recruitment or elastase activity. Thus, Dox potentiates inflammatory damage associated with lung fibrosis, elastin depletion and massive alveolar collapse, profoundly subverting lung structure in S. mansoni-infected mice.

Fabrication of Pentoxifylline-Loaded Hydroxyapatite/Alginate Scaffold for Bone Tissue Engineering

Background: Hydroxyapatite (HAP), as a common biomaterial in bone tissue engineering, can be fabricated in combination with other osteogenic agents. Pentoxifylline (PTX) is demonstrated to have positive roles in bone defect healing. Since local administration can diminish the systemic side effects of the drug, the objectives of the current in vitro study were to find the effects of PTX on the osteoblast functions for tissue engineering applications. Methods: a HAP scaffold was fabricated by casting the HAP slurry within polyurethane foam. The scaffold was enriched with 5 mg/mL PTX. Alginate (Alg) was used as drug carrier to regulate the PTX releasing rate. MG-63 osteosarcoma cells were cultured on 3D scaffolds and 2D Alg films in the presence or absence of PTX. Results: PTX did not affect the cell viability, attachment and phenotype. Also, the ultrastructure of the scaffolds was not modified by PTX enrichment. Alizarin red S staining showed that PTX has no effect on calcium deposition. Besides, Raman confocal microscopy demonstrated an increase in the organic matrix formation including proline, valine and phenylalanine deposition (represented collagen). Although PTX increased the total protein secretion, it led to a decrease in the alkaline phosphatase activity and vascular endothelial growth factor (VEGF) content. PTX reduced the hydration and degradation rates and it was released mainly at the first 24 hours of incubation. Conclusion: Based on our in vitro study, application of engineered PTX-loaded HAP scaffold in bone regeneration can act on behalf of organic matrix production, but not angiogenesis and mineralization.

Investigating the antifibrotic effect of the antiparasitic drug Praziquantel in in vitro and in vivo preclinical models

Tissue fibrosis underlies the majority of human mortality to date with close to half of all reported deaths having a fibrotic etiology. The progression of fibrosis is very complex and reputed irreversible once established. Although some preventive options are being reported, therapeutic options are still scarce and in very high demand, given the rise of diseases linked to fibroproliferative disorders. Our work explored four platforms, complementarily, in order to screen preventive and therapeutic potentials of the antiparasitic drug Praziquantel as a possible antifibrotic. We applied the mouse CCl₄-driven liver fibrosis model, the mouse chronic schistosomiasis liver fibrosis model, as well as novel 2D and 3D human cell-based co-culture of human hepatocytes, KCs (Kupffer cells), LECs (Liver Endothelial Cells), HSCs (Hepatic Stellate Cells) and/or myofibroblasts to mimic in vivo fibrotic responses and dynamics. Praziquantel showed some effect on fibrosis marker when preventively administered before severe establishment of fibrosis. However, it failed to potently reverse already established fibrosis. Together, we provided a novel sophisticated multi-assay screening platform to test preventive and therapeutic antifibrotic candidates. We further demonstrated a direct preventive potential of Praziquantel against the onset of fibrosis and the confirmation of its lack of therapeutic potential in reversing already established fibrosis.

The antioxidants resveratrol and N-acetylcysteine enhance anthelmintic activity of praziquantel and artesunate against Schistosoma mansoni

Background

Treatment of schistosomiasis has relied on the anthelmintic drug praziquantel (PZQ) for more than a generation. Despite its celebrated performance for treatment and control of schistosomiasis and other platyhelminth infections, praziquantel has some shortcomings and the inability of this drug to counteract disease sequelae prompts the need for novel therapeutic strategies.

Methods

Using a host-parasite model involving Biomphalaria glabrata and Schistosoma mansoni we established mechanical transformation of S. mansoni cercariae into newly transformed schistosomula (NTS) and characterized optimal culture conditions. Thereafter, we investigated the antischistosomal activity and ability of the antioxidants N-acetylcysteine (NAC) and resveratrol (RESV) to augment the performance of praziquantel and/or artesunate (AS) against larval stages of the parasite. Drug effects were evaluated by using an automated microscopical system to study live and fixed parasites and by transmission electron microscopy (TEM).

Results

Transformation rates of cercariae to schistosomula reached ~ 70% when the manipulation process was optimized. Several culture media were tested, with M199 supplemented with HEPES found to be suitable for S. mansoni NTS. Among the antioxidants studied, RESV alone or combined with anthelminthic drugs achieved better results rather N-acetylcysteine (NAC). TEM observations demonstrated that the combination of AS + RESV induced severe, extensive alterations to the tegument and subtegument of NTS when compared to the constituent compounds alone. Two anthelmintic–antioxidant combinations, praziquantel-resveratrol [combination index (CI) = 0.74] and artesunate-resveratrol (CI = 0.34) displayed moderate and strong synergy, respectively.

Conclusions

The use of viability markers including staining with propidium iodide increased the accuracy of drug screening assays against S. mansoni NTS. The synergies observed might be the consequence of increased action by RESV on targets of AS and PZQ and/or they may act through concomitantly on discrete targets to enhance overall antischistosomal action. Combinations of active agents, preferably with discrete modes of action including activity against developmental stages and/or the potential to ameliorate infection-associated pathology, might be pursued in order to identify novel therapeutic interventions.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3566-9) contains supplementary material, which is available to authorized users.

Biological activity of artemisinin-naphthoquine phosphate on Schistosoma haematobium stages and the vector Bulinus truncatus

BACKGROUND

Schistosoma haematobium infection is a major public health problem in most of Africa and the Middle East and praziquantel remains the only drug used for schistosomiasis control, therefore emergence of drug resistance is unavoidable. The antimalarial artemisinin-naphthoquine phosphate combination (co-ArNp) was recently documented to have promising effects on Schistosoma mansoni and its snail host.

METHODS

We conducted this in vitro study to assess the bioactivity of co-ArNp on S. haematobium and its snail vector Bulinus truncatus.

RESULTS

Treatment of S. haematobium worms with 1 μg/ml co-ArNp for 24 h reduced worm motility, while 20 μg/ml resulted in 25-100% mortality of adult flukes within 48-72 h. Incubation of S. haematobium miracidia and cercariae with the molluscicidal co-ArNp (50% lethal concentration 7.5 μg/ml) killed all the free larval stages within 40 and 15 min, respectively. Also, exposure of B. truncatus adult snails to 20 ppm of the combined regimen caused a mortality rate of 100% within 24 h.

CONCLUSIONS

Co-ArNp therapy has also shown encouraging activity against the other major human schistosome, S. haematobium, as well as its vector.

Combination Anthelmintic/Antioxidant Activity Against Schistosoma Mansoni

Schistosomiasis is a major neglected tropical disease. Treatment for schistosomiasis with praziquantel (PZQ), which is effective against the parasite, by itself is not capable to counteract infection-associated disease lesions including hepatic fibrosis. There is a pressing need for novel therapies. Due to their biological properties, antioxidant biomolecules might be useful in treating and reverting associated pathological sequelae. Here, we investigated a novel therapy approach based on a combination of anthelmintic drugs with antioxidant biomolecules. We used a host-parasite model involving Bioamphalaria glabrata and newly transformed schistosomula (NTS) of Schistosoma mansoni. For in vitro drug screening assays, was selected several antioxidants and evaluated not only antischistosomal activity but also ability to enhance activity of the anthelmintic drugs praziquantel (PZQ) and artesunate (AS). The morphological alterations induced by compounds alone/combined were assessed on daily basis using an inverted and automated microscope to quantify NTS viability by a fluorometric-based method. The findings indicated that not only do some antioxidants improve antischistosomal activity of the two anthelmintics, but they exhibit activity per se, leading to high mortality of NTS post-exposure. The combination index (CI) of PZQ + Mel (CI = 0.80), PZQ + Resv (CI = 0.74), AS + Resv (CI = 0.34), AS + NAC (CI = 0.89), VDT + Flav (CI = 1.03) and VDT + Resv (CI = 1.06) reveal that they display moderate to strong synergism. The combination of compounds with discrete mechanisms of action might provide a valuable adjunct to contribution for treatment of schistosomiasis-associated disease.

The natural compound 7-epiclusianone inhibits superoxide dismutase activity in Schistosoma mansoni

Schistosomiasis - caused by trematodes from the genus Schistosoma - affects more than 200 million people worldwide. Growing resistance to therapy with praziquantel (PZQ) has encouraged the search for novel treatments against this neglected disease. The compound 7-epiclusianone (7-epi) - isolated from 'bacupari' (the fruit of the Gracinia brasiliensis tree) - has promising activity against Schistosoma mansoni in vitro, damaging the parasite's tegument. However, the target and mechanism of action of 7-epi have not been identified. Here, we examined the possibility that 7-epi harms the tegument by inhibiting parasite superoxide dismutase (SOD), which protects the tegument from damage by reactive oxygen species produced by host immune cells. Molecular docking analysis in silico suggested strong interactions between 7-epi and S. mansoni cytosolic superoxide dismutase (SmCtSOD) at allosteric cavities. Schistosoma mansoni couples were cultivated ex vivo with 12.44-198.96 μm 7-epi for 24 h, and then parasite extracts were tested for lipid peroxidation (as a surrogate for oxidative stress), and SOD activity and expression. Lipid peroxidation levels increased after incubation with concentrations ≥99.48 μm 7-epi, and this compound reduced SOD activity at concentrations ≥24.87 μm. However, contact with 7-epi did not alter SOD expression, by quantitative real-time polymerase chain reaction (qRT-PCR). Our results show that the inhibition of SmCtSOD is partly responsible for the tegument detachment observed after incubation with 7-epi, but is not the only cause of the antiparasitic action of this compound in vitro.

Repurposing Pentoxifylline for the Treatment of Fibrosis: An Overview

Fibrosis is a potentially debilitating disease with high morbidity rates. It is estimated that half of all deaths that occur in the USA are attributed to fibrotic disorders. Fibrotic disorders are characterized primarily by disruption in the extracellular matrix deposition and breakdown equilibrium, leading to the accumulation of excessive amounts of extracellular matrix. Given the potentially high prevalence of fibrosis and the paucity of agents currently available for the treatment of this disease, there is an urgent need for the identification of drugs that can be utilized to treat the disease. Pentoxifylline is a methylxanthine derivative that is currently approved for the treatment of vascular diseases, in particular, claudication. Pentoxifylline has three main properties: improving the rheological properties of blood, anti-inflammatory, and antioxidative. Recently, the effectiveness of pentoxifylline in the treatment of fibrosis via attenuating and reversing fibrotic lesions has been demonstrated in several clinical trials and animal studies. As a result of the limited availability of antifibrotic agents in the long-term treatment of fibrosis that can attenuate and even reverse fibrotic lesions effectively, it would be of particular importance to consider the potential clinical utility of pentoxifylline in the treatment of fibrosis. Thus, this paper discusses the evolving roles of pentoxifylline in the treatment of different types of fibrosis.

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-β1), 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-β1 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.

Pentoxifylline inhibits liver fibrosis via hedgehog signaling pathway

Infection of schistosomiasis japonica may eventually lead to liver fibrosis, and no effective antifibrotic therapies are available but liver transplantation. Hedgehog (HH) signaling pathway has been involved in the process and is a promising target for treating liver fibrosis. This study aimed to explore the effects of pentoxifylline (PTX) on liver fibrosis induced by schistosoma japonicum infection by inhibiting the HH signaling pathway. Phorbol12-myristate13-acetate (PMA) was used to induce human acute mononuclear leukemia cells THP-1 to differentiate into macrophages. The THP-1-derived macrophages were stimulated by soluble egg antigen (SEA), and the culture supernatants were collected for detection of activation of macrophages. Cell Counting Kit-8 (CCK-8) was used to detect the cytotoxicity of the culture supernatant and PTX on the LX-2 cells. The LX-2 cells were administered with activated culture supernatant from macrophages and(or) PTX to detect the transforming growth factor-β gene expression. The mRNA expression of shh and gli-1, key parts in HH signaling pathway, was detected. The mRNA expression of shh and gli-1 was increased in LX-2 cells treated with activated macrophages-derived culture supernatant, suggesting HH signaling pathway may play a key role in the activation process of hepatic stellate cells (HSCs). The expression of these genes decreased in LX-2 cells co-cultured with both activated macrophages-derived culture supernatant and PTX, indicating PTX could suppress the activation process of HSCs. In conclusion, these data provide evidence that PTX prevents liver fibrogenesis in vitro by the suppression of HH signaling pathway.

The hepatoprotective activity of blue green algae in Schistosoma mansoni infected mice

This study aims to evaluate the immunomodulatory effects of a natural product, blue green algae (BGA) (100 mg/kg BW), alone or combined with praziquantel PZQ (250 mg/kg BW) on granulomatous inflammation, liver histopathology, some biochemical and immunological parameters in mice infected with Schistosoma mansoni. Results showed that the diameter and number of egg granuloma were significantly reduced after treatment of S. mansoni-infected mice with BGA, PZQ and their combination. The histopathological alterations observed in the liver of S. mansoni-infected mice were remarkably inhibited after BGA treatments. BGA decreased the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) as well as the level of total protein (TP) while the level of albumin was increased. Treatment of infected mice with BGA, PZQ as well as their combination led to significant elevation in the activities of hepatic antioxidant enzymes glutathione peroxidase (GPX) and glutathione-S-transferase (GST) as compared with control group. Combination of BGA and PZQ resulted in significant reduction in the level of intercellular adhesion molecules-1 (ICAM-1), vascular adhesion molecules-1 (VCAM-1) and tumor necrosis factor-alpha (TNF-α) when compared to those of the S. mansoni-infected group. Overall, BGA significantly inhibited the liver damage accompanied with schistosomiasis, exhibited a potent antioxidant and immunoprotective activities. This study suggests that BGA can be considered as promising for development a complementary and/or alternative medicine against schistosomiasis.

Protective effects of pentoxifylline in pulmonary inflammation are adenosine receptor A2A dependent

Pentoxifylline (PTX) has been shown to exert anti-inflammatory effects in experimental acute lung injury. However, results in humans were controversial. Recent in vitro studies suggested that the adenosine receptor A2A may be required for PTX to be effective. Therefore, we studied the association between A2A and PTX in a murine model of LPS-induced pulmonary inflammation. PTX treatment (10 mg/kg) reduced cellular influx (by 40%), microvascular permeability (30%), and the release of chemotactic cytokines into the alveolar space (TNF-α 60%, IL-6 60%, and CXCL2/3 53%, respectively). These protective effects were abolished completely in A2A(-/-) mice and in wild-type mice that had been treated with the selective A2A antagonist (1 mg/kg), but effects were not different in mice with altered adenosine levels. In vitro transmigration assays revealed a pivotal role of the endothelium in PTX-mediated PMN migration, with a reduction of 50% (2 mM PTX). This effect was also A2A dependent. Further, oxidative burst of human PMNs was A2A-dependently reduced by 53% after PTX treatment. In summary, PTX exhibits its anti-inflammatory effects in LPS-induced lung injury through an A2A-dependent pathway. These results will help to better understand previous conflicting data on PTX in inflammation and will direct further studies to consider the predominant role of A2A.

Effect of ketoconazole, a cytochrome P450 inhibitor, on the efficacy of quinine and halofantrine against Schistosoma mansoni in mice

The fear that schistosomes will become resistant to praziquantel (PZQ) motivates the search for alternatives to treat schistosomiasis. The antimalarials quinine (QN) and halofantrine (HF) possess moderate antischistosomal properties. The major metabolic pathway of QN and HF is through cytochrome P450 (CYP) 3A4. Accordingly, this study investigates the effects of CYP3A4 inhibitor, ketoconazole (KTZ), on the antischistosomal potential of these quinolines against Schistosoma mansoni infection by evaluating parasitological, histopathological, and biochemical parameters. Mice were classified into 7 groups: uninfected untreated (I), infected untreated (II), infected treated orally with PZQ (1,000 mg/kg) (III), QN (400 mg/kg) (IV), KTZ (10 mg/kg)+QN as group IV (V), HF (400 mg/kg) (VI), and KTZ (as group V)+HF (as group VI) (VII). KTZ plus QN or HF produced more inhibition (P<0.05) in hepatic CYP450 (85.7% and 83.8%) and CYT b5 (75.5% and 73.5%) activities, respectively, than in groups treated with QN or HF alone. This was accompanied with more reduction in female (89.0% and 79.3%), total worms (81.4% and 70.3%), and eggs burden (hepatic; 83.8%, 66.0% and intestinal; 68%, 64.5%), respectively, and encountering the granulomatous reaction to parasite eggs trapped in the liver. QN and HF significantly (P<0.05) elevated malondialdehyde levels when used alone or with KTZ. Meanwhile, KTZ plus QN or HF restored serum levels of ALT, albumin, and reduced hepatic glutathione (KTZ+HF) to their control values. KTZ enhanced the therapeutic antischistosomal potential of QN and HF over each drug alone. Moreover, the effect of KTZ+QN was more evident than KTZ+HF.

Pentoxifylline decreases oxidized lipid products in nonalcoholic steatohepatitis: new evidence on the potential therapeutic mechanism

Pentoxifylline (PTX) improved the histological features of nonalcoholic steatohepatitis (NASH) in a recent randomized placebo-controlled trial. However, the underlying mechanism responsible for the beneficial effects of PTX in NASH remains unidentified. A key role of lipid oxidation in the pathogenesis and progression of NASH has been established. PTX is known to decrease free-radical-mediated oxidative stress and inhibit lipid oxidation. The primary aim of this study was to evaluate the effects of PTX on levels of lipid oxidation products in patients with NASH. Levels of multiple structurally specific oxidized fatty acids including hydroxy-octadecadienoic acids (HODEs), oxo-octadecadienoic acids (oxoODEs), and hydroxy-eicosatetraenoic acids (HETEs) were quantified by mass spectrometry in plasma obtained at baseline and at study completion in patients who completed 1 year of therapy with PTX or placebo in a randomized controlled trial. Therapy with PTX resulted in significant decreases in 9-HODE and 13-oxoODE, oxidized lipid products of linoleic acid (LA) linked to histological severity in nonalcoholic fatty liver disease. Similarly, PTX therapy was associated with significant decreases in 8-HETE, 9-HETE, and 11-HETE compared to placebo. Statistically significant correlations were demonstrated between the decrease in HODEs and oxoODEs and improved histological scores of fibrosis and between the decrease in HETEs and improved lobular inflammation.

CONCLUSION

Therapy with PTX compared to placebo was associated with a significant reduction of oxidized fatty acids. This novel evidence supports that the beneficial effects of PTX in patients with NASH are likely partly mediated through decreasing lipid oxidation, largely free-radical-mediated lipid oxidation. Additionally, this is the first report on the link between decreased oxidized lipid products and improved histological disease in the setting of a therapeutic trial in NASH.

Current applications of oogram methodology in experimental schistosomiasis; fecundity of female Schistosoma mansoni and egg release in the intestine of AKR/J mice following immunomodulatory treatment with pentoxifylline

Oogram methodology permitted a direct assessment of the fecundity of Schistosoma mansoni and the passage of parasite eggs from mesenteric vessels into the intestinal lumen in AKR/J mice that had been infected via the intraperitoneal route with 60 cercariae of the trematode and later subjected to short-term subcutaneous treatments with pentoxifylline (PTX). The administration of PTX did not change oviposition kinetics, the individual fecundity of female parasites (as determined by the study of the ratio of second-stage S. mansoni eggs per g intestine/number of female parasites recovered from the portal system), nor the number of mature and dead eggs retained in the host tissue, though the drug has known immunomodulatory effects, as shown previously in experimental schistosomiasis. A better appraisal was also carried out, including the study of statistical parameters, concerning the utilization of the ratios of each stage of immature eggs (first to fourth) per g intestine/number of female worms from the portal system. The second-stage eggs had the lowest variability, confirming that the utilization of this stage as an indicator of the individual fecundity of parasite females is indeed viable. In the light of our findings, current uses of oogram methodology are discussed. Moreover, additional consideration is given to data obtained in the present study concerning intraperitoneal infection with S. mansoni cercariae in both untreated and treated mice of the AKR/J strain, such as the recovery of mature worms, eggs and free granulomas from the peritoneal cavity of these rodents.