FioSchisto's expert perspective on implementing WHO guidelines for schistosomiasis control and transmission elimination in Brazil.

The World Health Organization (WHO) recognizes schistosomiasis as one of the Neglected Tropical Diseases targeted for global elimination in the 2030 Agenda of the Sustainable Development Goals. In Brazil, schistosomiasis mansoni is considered a public health problem, particularly prevalent among vulnerable populations living in areas with poor environmental and sanitary conditions. In 2022, the WHO published a Guideline encompassing recommendations to assist national programs in endemic countries in achieving morbidity control, eliminating schistosomiasis as a public health problem, and advancing towards interrupting transmission. The perspectives presented here, collectively prepared by members of the Oswaldo Cruz Foundation's (Fiocruz) Schistosomiasis Translational Program (FioSchisto), along with invited experts, examine the feasibility of the WHO recommendations for the Brazilian settings, providing appropriate recommendations for public health policies applicable to the epidemiological reality of Brazil, and suggests future research to address relevant issues. In Brazil, the provision of safe water and sanitation should be the key action to achieve schistosomiasis elimination goals. The agencies involved in measures implementation should act together with the Primary Care teams for planning, executing, monitoring, and evaluating actions in priority municipalities based on their epidemiological indicators. Host snails control should prioritize judicious ecological interventions at breeding sites. The Information, Education, and Communication (IEC) strategy should be associated with water and sanitation and other control actions, actively involving school community. To identify infected carriers, FioSchisto recommends a two-stage approach of immunological and molecular tests to verify transmission interruption during the intervention and beyond. Praziquantel administration should be done under medical supervision at the Primary Care level. MDA should be considered in exceptional settings, as a measure of initial attack strategy in locations presenting high endemicity, always integrated with water and sanitation, IEC, and snail control. To assist decision-making, as well as the monitoring and evaluation of strategic actions, there is a need for an Information System. FioSchisto considers this systematization essential to make investments in strategic research to support the improvement of schistosomiasis control actions. Efforts toward schistosomiasis elimination in Brazil will succeed with a paradigm shift from the vertical prescriptive framework to a community-centered approach involving intersectoral and interdisciplinary collaboration.

Therapeutic Potential of Natural Products in the Treatment of Schistosomiasis.

It is estimated that 250 million people worldwide are affected by schistosomiasis. Disease transmission is related to the poor sanitation and hygiene habits that affect residents of impoverished regions in tropical and subtropical countries. The main species responsible for causing disease in humans are Schistosoma Mansoni, S. japonicum, and S. haematobium, each with different geographic distributions. Praziquantel is the drug predominantly used to treat this disease, which offers low effectiveness against immature and juvenile parasite forms. In addition, reports of drug resistance prompt the development of novel therapeutic approaches. Natural products represent an important source of new compounds, especially those obtained from plant sources. This review compiles data from several in vitro and in vivo studies evaluating various compounds and essential oils derived from plants with cercaricidal and molluscicidal activities against both juvenile and adult forms of the parasite. Finally, this review provides an important discussion on recent advances in molecular and computational tools deemed fundamental for more rapid and effective screening of new compounds, allowing for the optimization of time and resources.

Changes in air pollution due to COVID-19 lockdowns in 2020: Limited effect on NO2, PM2.5, and PM10 annual means compared to the new WHO Air Quality Guidelines.

Background: Lockdowns have been fundamental to decreasing disease transmission during the COVID-19 pandemic even after vaccines were available. We aimed to evaluate and compare changes in air quality during the first year of the pandemic in different cities around the world, investigate how these changes correlate with changes in mobility, and analyse how lockdowns affected air pollutants' annual means. Methods: We compared the concentrations of NO2, PM2.5, and PM10 in 42 cities around the world in the first months of the pandemic in 2020 to data from 2016-2019 and correlated them with changes in mobility using Human Development Indexes (HDIs). Cities with the highest decreases in air pollutants during this period were evaluated for the whole year 2020. We calculated the annual means for these cities and compared them to the new World Health Organization (WHO) Air Quality Guidelines. A Student's t-test (95% confidence interval) was used to evaluate significant changes. Results: Highest decreases in NO2, PM2.5, and PM10 were between -50 and -70%. Cities evaluated for the whole year 2020 generally showed a recovery in air pollution levels after the initial months of the pandemic, except for London. These changes positively correlated with year-long mobility indexes for NO2 and PM2.5 for some cities. The highest reductions in air pollutants' annual means were from -20 to -35%. In general, decreases were higher for NO2, compared to PM2.5 and PM10. All analysed cities showed annual means incompliant with the new WHO Air Quality Guidelines for NO2 of 10 µg/m3, with values 1.7 and 4.3 times higher. For PM2.5, all cities showed values 1.3 to 7.6 times higher than the WHO Guidelines of 5 µg/m3, except for New Delhi, with a value 18 times higher. For PM10, only New York complied with the new guidelines of 15 µg/m3 and all the other cities were 1.1 to 4.2 times higher, except for New Delhi, which was 11 times higher. Conclusions: These data show that even during a pandemic that highly affected mobility and economic activities and decreased air pollution around the world, complying with the new WHO Guidelines will demand a global strategical effort in the way we generate energy, move in and around the cities, and manufacture products.

The prophylactic and anti-fibrotic activity of phthalimido-thiazole derivatives in schistosomiasis mansoni.

Schistosomiasis mansoni is considered a serious public health problem. As praziquantel is the only drug recommended by the World Health Organization for the treatment and control of schistosomiasis, the development of new drugs is of great significance. In this work, we present the antischistosomal activity of a small set of phthalimido-thiazole derivatives against Schistosoma mansoni. The effects of those derivatives on the viability of larvae juveniles and adult parasites, production and development of eggs, mortality of schistosomules in vitro by counting worms, and stages of eggs of infected animals in acute and chronic phases were evaluated, resulting in the identification of new multistage antischistosomal compounds. Additionally, a study of liver fibrogenesis was released. The phthalimido-thiazole derivatives, compounds 2b-d, 2h-j, had shown activity on schistosomules, achieving 100% mortality even at 5 mg/mL, in the first 24 h. In the chronic phase of schistosomiasis infection, compound 2i promoted a reduction in the number of immature eggs, an increase in the number of non-viable parasite eggs, a reduction in the average number of eggs in the liver and intestine, decrease in the levels of hydroxyproline in the liver, and a reduction in the areas of hepatic fibrosis. This compound also promoted an increase of IL-10 and a reduction in the level of TNF-α in the liver. Accordingly, the phthalimide-thiazole scaffold is a new starting point for the development of multistage compounds that affect S. mansoni viability, egg formation, and production.

Effects of Migonemyia migonei salivary gland homogenates on Leishmania (Viannia) braziliensis infection in BALB/c mice.

Cutaneous leishmaniasis caused by Leishmania (Viannia) braziliensis is the most widespread clinical form of leishmaniasis in the Americas. Migonemyia migonei is a widely distributed phlebotomine sand fly species in Brazil and has been implicated as a vector for L. (V.) braziliensis. In the present study, we investigated the effects of salivary gland homogenates (SGH) of Mg. migonei on the course of L. (V.) braziliensis infection in BALB/c mice. Mice were separated into four groups (six mice per group): CTRL (uninfected mice); SGH (mice inoculated with Mg. migonei SGH); SGH+LEISH (mice inoculated with Mg. migonei SGH plus L. (V.) braziliensis promastigotes); LEISH (mice inoculated with L. (V.) braziliensis promastigotes). Mice were followed up for 8 weeks and the cellular immune response was evaluated by flow cytometry at the end of the experiment. Analysis of cytokine production by splenic cells stimulated with 0.5 SGH, 0.25 SGH of Mg. migonei or L. (V.) braziliensis soluble antigen stimulation (LSA) demonstrated that upon stimulation with SGH 0.25, the production of IL-17A and TNF was not sustained in the SGH group, with decreasing levels of these cytokines after 5 days compared to 3 days of incubation. Analyzing the production of cytokines after LSA stimulation, we observed lower levels of IL-17A in the SGH group after 5 days compared to 3 days. The same was observed for IFN-γ in the SGH group. Yet, the levels of TNF were significantly higher in the LEISH group after 5 days compared to 3 days. Among SGH+LEISH and LEISH mice, three animals in each group developed skin lesions on the tail, the mean lesion size was significantly higher in the LEISH group. Our study suggests that Mg. migonei SGH may modulate BALB/c immune response, as reflected by the low production or early decrease of pro-inflammatory cytokines in splenic cell cultures following stimulation with L. (V.) braziliensis antigen. Our data also suggest that Mg. migonei saliva may reduce the lesion size in BALB/c mice, but further research with a larger sample size is needed to confirm this hypothesis.

In vitro and in vivo activities of multi-target phtalimido-thiazoles on Schistosomiasis mansoni.

Schistosomicidal activity of six phthalimido-thiazoles derivatives with substitutions at the position three of the thiazole ring were analyzed in an experimental model. The substituents biphenyl (2i) and 2- naphthyl (2j) at a concentration of 80 µg/mL caused 100% mortality of the parasite in culture after 24 h and 48 h respectively. An evaluation of ultrastructural parasites showed damage in the tegument, formation of bubbles and partial destruction of the tubercles. The in vivo anti-parasitic activity with the derivate 2i was performed by administering it orally and intraperitoneally in a 400 mg/kg/5days regimen. Decreases in the number of eggs in the gut (45.1%) and a reduction of the percentage of mature (23.7%) and increased unviable (53.8%) eggs were observed. Our results also showed a reduction in the number of recovered worms after treatment with 2i (oral administration: 81, 25%). The results demonstrated that the prototypes which were tested had a significant anti-schistosomal effect against S. mansoni, suggesting that these derivatives are promising candidates for further research into the chemotherapy of schistosomiasis.

Adoptive Transfer of Bone Marrow-Derived Monocytes Ameliorates Schistosoma mansoni -Induced Liver Fibrosis in Mice.

Liver diseases are a major health problem worldwide leading to high mortality rates and causing a considerable economic burden in many countries. Cellular therapies as potential treatments for liver diseases have proven beneficial in most of the conditions. In recent years, studies involving therapy with bone marrow cells have been implemented to promote liver regeneration and to reduce hepatic fibrosis, however identifying the cell population present in the bone marrow that is responsible for hepatic improvement after therapy is still necessary. The aim of the present study was the evaluation of the therapeutic efficacy of monocytes obtained from bone marrow in fibrosis resulting from S. mansoni infection in C57BL/6 mice. Monocytes were isolated by immunomagnetic separation and administered to the infected animals. The effects of treatment were evaluated through morphometric, biochemical, immunological and molecular analyzes. Monocyte therapy promoted reduction of liver fibrosis induced by S. mansoni infection, associated with a decrease in production of inflammatory and pro-fibrogenic mediators. In addition, monocyte infusion caused downregulation of factors associated with the M1 activation profile, as well as upregulation of M2reg markers. The findings altogether reinforce the hypothesis that the predominance of M2reg macrophages, producers of immunosuppressive cytokines, may favor the improvement of hepatic fibrosis in a preclinical model, through fibrous tissue remodeling, modulation of the inflammatory response and fibrogenesis.

Schistosomicidal and prophylactic activities of phthalimido-thiazoles derivatives on schistosomula and adult worms.

Schistosomiasis is a major public health problem worldwide, especially in poor communities. Praziquantel is currently the only drug available to treat schistosomiasis and it shows low efficacy against schistosomula and juveniles stages of Schistosoma mansoni, allowing lower cure rate in areas with high endemicity. There is an urgent need to identify new antischistosomal drugs. Previous works identified phthalimido-thiazoles as privileged structures acting as schistossomicidal agent. In this way, a phthalimido-thiosemicarbazide intermediate and eight phthalimido-thiazoles derivatives were evaluated concerning the in vitro antischistosomal activity compounds in adult phase of Schistosoma mansoni and examined alterations on the tegumental surface. The results revealed that compounds 2f, 2 l and 2 m caused significant mortality in adult worms at concentrations range of 20 µg/mL to 100 µg/mL. These compounds were also selected in view to verify the activity against the schistosomula. Compound 2 m promoted 100% of mortality of larval forms until doses of 2.5 µg/mL within 48 h. In addition, when compound 2 m was administered orally at dose of 200 mg/kg for 5 consecutive days to the infected mouse with adult schistosomes, a reduction in the parasite burden was observed. Furthermore, scanning electron microscopy revealed that compound 2 m kill the parasite by tegumental damage and bubbles generation.

In vitro and in vivo models for studying Zika virus biology.

The emergence and rapid spread of Zika virus (ZIKV) in the Americas has prompted the development of in vitro and in vivo models to understand several aspects of ZIKV biology and boost the development of vaccines and antivirals. In vitro model studies include reverse genetics systems, two-dimensional (2D) cell models, such as primary cells and cell lines, and ex vivo three-dimensional (3D) models derived from skin, brain and placenta. While these models are cost-effective and allow rigorous control of experimental variables, they do not always recapitulate in vivo scenarios. Thus, a number of in vivo models have been developed, including mosquitoes (Aedes sp. and Culex sp.), embryonated chicken eggs, immunocompetent and immunodeficient mice strains, hamsters, guinea pigs, conventional swine and non-human primates. In this review, we summarize the main research systems that have been developed in recent years and discuss their advantages, limitations and main applications.

Phthalimido-thiazole as privileged scaffold: activity against immature and adult worms of Schistosoma mansoni.

Phthalimide, 1,3-thiazole, and thiazolidinone cores are considered privileged scaffolds and represent an attractive starting point to design new bioactive compounds for neglected tropical disease (NTD). Schistosomiasis is a NTD, caused by Schistosoma worms which praziquantel (PZQ) is the only drug used to treat humans, but the decrease in the effect after treatment has been reported. Recently, some phthalimide-thiazole derivatives exhibited in vitro antischistosomal activity against adult worms with significant ultrastructural changes and a lower cytotoxic effect on splenocytes. This new biological phthalimido-thiazole profile has motivated us to evaluate a new generation of such molecules in immature and adult worms. Thus, a phthalimido-thiazolidinone derivative, (3c), and three phthalimido-thiazoles (6c, 7a, and 7h) were evaluated concerning their in vitro activity on schistosomulae and adult worms. The results showed that these compounds brought a significant reduction on the mortality, inhibited oviposition, and then induced mortality in immature and adult worms alike. According to scanning electron microscopy, the tegument was the principal target for 7a and 7h and revealed gradual damage to the tegument surface, inducing destruction and decomposition of the tegument in the same areas and exposition of subtegumental tissue and of muscle tissue. Furthermore, they caused less toxicity in splenocytes than PZQ. Compounds 7a and 7h revealed to possess promising activity against larval forms. According to the present study, the privileged structure phthalimido-thiazoles act as a molecular framework that has antischistosomal activity and most form the basis to the next pre-clinical tests. Graphical abstract.

Bone marrow-derived monocyte infusion improves hepatic fibrosis by decreasing osteopontin, TGF-ß1, IL-13 and oxidative stress.

AIM: To evaluate the therapeutic effects of bone marrow-derived CD11b+CD14+ monocytes in a murine model of chronic liver damage. METHODS: Chronic liver damage was induced in C57BL/6 mice by administration of carbon tetrachloride and ethanol for 6 mo. Bone marrow-derived monocytes isolated by immunomagnetic separation were used for therapy. The cell transplantation effects were evaluated by morphometry, biochemical assessment, immunohistochemistry and enzyme-linked immunosorbent assay. RESULTS: CD11b+CD14+ monocyte therapy significantly reduced liver fibrosis and increased hepatic glutathione levels. Levels of pro-inflammatory cytokines, including tumor necrosis factor-α, interleukin (IL)-6 and IL-1ß, in addition to pro-fibrotic factors, such as IL-13, transforming growth factor-ß1 and tissue inhibitor of metalloproteinase-1 also decreased, while IL-10 and matrix metalloproteinase-9 increased in the monocyte-treated group. CD11b+CD14+ monocyte transplantation caused significant changes in the hepatic expression of α-smooth muscle actin and osteopontin. CONCLUSION: Monocyte therapy is capable of bringing about improvement of liver fibrosis by reducing oxidative stress and inflammation, as well as increasing anti-fibrogenic factors.

In vivo study of schistosomicidal action of 1-benzyl-4-[(4-fluoro-phenyl)-hydrazono]-5-thioxo-imidazolidin-2-one.

Praziquantel has been the drug most widely used therapy against different forms of schistosomiasis around the world. However, this treatment has shown ineffective in humans and in experimental models of Schistosoma mansoni. New therapeutic alternatives have been tested, including the imidazolidine derivative LPSF/PT-09, which has shown high therapeutic potential in vitro. In this work, we tested the schistosomal activity of this derivative in doses of 250mg/kg and 200mg/kg in mice experimentally infected with a high parasite load of S. mansoni. Parasitological evaluations related to the number of S. mansoni worms and their oviposition were performed during the acute phase of the disease and have demonstrated moderate effectiveness of 30-54,4%. However, LPSF/PT-09 did not influence oviposition of the parasites or the embryonic development of the eggs. The results obtained in this model showed that the imidazolidine derivative LPSF/PT-09 presented significant antischistosomal activity in vivo, posing as a potential candidate for this class of drugs. However, a better understanding of the pharmacokinetics and pharmacodynamics of the imidazolidine derivative LPSF/PT-09 is needed.

Pharmacological Basis for Traditional Use of the Lippia thymoides.

The aim of this study was to evaluate crude extracts and fractions from leaves and stems of Lippia thymoides and to validate their use in folk medicine. In vitro antioxidant and antimicrobial activities and in vivo wound healing in rats, baker yeast-induced fever in young rats, and acute oral toxicity in mice assays were realized. The crude extracts and their dichloromethane and ethyl acetate fractions had potent radical-scavenging activity against the DPPH but were not effective in the ß-carotene bleaching method. The dichloromethane fraction from the leaves extract showed the broadest spectrum of activity against S. aureus, B. cereus, and C. parapsilosis. The animals treated with crude extracts showed no difference in wound healing when compared with the negative control group. The crude extract from leaves (1200 mg/kg) has equal efficacy in reducing temperature in rats with hyperpyrexia compared to dipyrone (240 mg/kg) and is better than paracetamol (150 mg/kg). In acute toxicity test, crude extract of leaves from Lippia thymoides exhibited no mortality and behavioral changes and no adverse effects in male and female mice. This work validates the popular use of Lippia thymoides for treating the wound and fever, providing a source for biologically active substances.

Evaluation of the anti-Schistosoma mansoni activity of thiosemicarbazones and thiazoles.

Schistosomiasis is a chronic and debilitating disease caused by a trematode of the genus Schistosoma and affects over 207 million people. Chemotherapy is the only immediate recourse for minimizing the prevalence of this disease and involves predominately the administration of a single drug, praziquantel (PZQ). Although PZQ has proven efficacy, there is a recognized need to develop new drugs as schistosomicides since studies have shown that repeated use of this drug in areas of endemicity may cause a temporary reduction in susceptibility in isolates of Schistosoma mansoni. Hydrazones, thiosemicarbazones, phthalimides, and thiazoles are thus regarded as privileged structures used for a broad spectrum of activities and are potential candidates for sources of new drug prototypes. The present study determined the in vitro schistosomicidal activity of 10 molecules containing these structures. During the assays, parameters such motility and mortality, oviposition, morphological changes in the tegument, cytotoxicity, and immunomodulatory activity caused by these compounds were evaluated. The results showed that compounds formed of thiazole and phthalimide led to higher mortality of worms, with a significant decline in motility, inhibition of pairing and oviposition, and a mortality rate of 100% starting from 144 h of exposure. These compounds also stimulated the production of nitric oxide and tumor necrosis factor alpha (TNF-α), thereby demonstrating the presence of immunomodulatory activity. The phthalyl thiazole LpQM-45 caused significant ultrastructural alterations, with destruction of the tegument in both male and female worms. According to the present study, phthalyl thiazole compounds possess antischistosomal activities and should form the basis for future experimental and clinical trials.

Transplantation of bone marrow cells decreases tumor necrosis factor-α production and blood-brain barrier permeability and improves survival in a mouse model of acetaminophen-induced acute liver disease.

BACKGROUND AIMS: Acute liver failure (ALF), although rare, remains a rapidly progressive and frequently fatal condition. Acetaminophen (APAP) poisoning induces a massive hepatic necrosis and often leads to death as a result of cerebral edema. Cell-based therapies are currently being investigated for liver injuries. We evaluated the therapeutic potential of transplantation of bone marrow mononuclear cells (BMC) in a mouse model of acute liver injury. METHODS: ALF was induced in C57Bl/6 mice submitted to an alcoholic diet followed by fasting and injection of APAP. Mice were transplanted with 10(7) BMC obtained from enhanced green fluorescent protein (GFP) transgenic mice. RESULTS: BMC transplantation caused a significant reduction in APAP-induced mortality. However, no significant differences in serum aminotransferase concentrations, extension of liver necrosis, number of inflammatory cells and levels of cytokines in the liver were found when BMC- and saline-injected groups were compared. Moreover, recruitment of transplanted cells to the liver was very low and no donor-derived hepatocytes were observed. Mice submitted to BMC therapy had some protection against disruption of the blood-brain barrier, despite their hyperammonemia, and serum metalloproteinase (MMP)-9 activity similar to the saline-injected group. Tumor necrosis factor (TNF)-α concentrations were decreased in the serum of BMC-treated mice. This reduction was associated with an early increase in interleukin (IL)-10 mRNA expression in the spleen and bone marrow after BMC treatment. CONCLUSIONS: BMC transplantation protects mice submitted to high doses of APAP and is a potential candidate for ALF treatment, probably via an immunomodulatory effect on TNF-α production.

Reduction of galectin-3 expression and liver fibrosis after cell therapy in a mouse model of cirrhosis.

BACKGROUND AIMS: Cirrhosis, end-stage liver disease, is caused by different mechanisms of injury, associated with persistent inflammation. Galectin-3 is an important regulator of fibrosis that links chronic inflammation to fibrogenesis. We investigated the role of bone marrow cell (BMC) transplantation in chronic inflammation and hepatic fibrosis. METHODS: Liver cirrhosis was induced by administration of carbon tetrachloride and ethanol to wild-type C57BL/6 or bone marrow chimeric mice. Bone marrow chimeras were generated by lethal irradiation and transplantation with BMC obtained from green fluorescent protein (GFP(+) )donors. Wild-type cirrhotic mice were transplanted with BMC without irradiation. Livers from chimeras and cirrhotic transplanted mice were obtained for evaluation of inflammation, fibrosis and regulatory factors [galectin-3, matrix metallopeptidase (MMP)-9, tissue inhibitor of metalloproteinase (TIMP)-1 and transforming growth factor (TGF)-ß]. RESULTS: The development of cirrhosis was associated with increased expression of galectin-3 by F4/80(+) cells and intense migration of BMC to the liver. Furthermore, when transplanted after the establishment of cirrhosis, BMC also migrated to the liver and localized within the fibrous septa. Two months after BMC therapy, cirrhotic mice had a significant reduction in liver fibrosis and expression of type I collagen. We did not find any difference in levels of TGF-ß, TIMP-1 and MMP-9 between saline and BMC groups. However, the numbers of inflammatory cells, phagocytes and galectin-3(+) cells were markedly lower in the livers of cirrhotic mice treated with BMC. CONCLUSIONS: Our results demonstrate an important role for BMC in the regulation of liver fibrosis and that transplantation of BMC can accelerate fibrosis regression through modulatory mechanisms.

Current status of stem cell therapy for liver diseases.

Liver failure is one of the main causes of death worldwide and is a growing health problem. Since the discovery of stem cell populations capable of differentiating into specialized cell types, including hepatocytes, the possibility of their utilization in the regeneration of the damaged liver has been a focus of intense investigation. A variety of cell types were tested both in vitro and in vivo, but the definition of a more suitable cell preparation for therapeutic use in each type of liver lesions is yet to be determined. Here we review the protocols described for differentiation of stem cells into hepatocytes, the results of cell therapy in animal models of liver diseases, as well as the available data of the clinical trials in patients with advanced chronic liver disease.

Chemotherapeutic effects on larval stages of Schistosoma mansoni during infection and re-infection of mice.

The sensitivity of the larval stages of Schistosoma mansoni to chemotherapy with praziquantel and oxamniquine was tested in mice during primary and secondary infections and after different intervals from cercarial exposure. Worm recovery by perfusion of the porto-mesenteric system, followed by counting and a morphometric study of the parasite, allowed the conclusion that the relative resistance of the larval stages of S. mansoni to schistosomicide drugs, demonstrated in primary infections, also persists when the host is already infected. This indicates that a therapeutic failure may result when an infected host is treated some time after being re-infected, because of the presence of migrating, drug-resistant, immature forms of the parasite.