Suelen Santos da Silva

Nitric oxide and Brazilian propolis combined accelerates tissue repair by modulating cell migration, cytokine production and collagen deposition in experimental leishmaniasis.

The fact that drugs currently used in the treatment of Leishmania are highly toxic and associated with acquired resistance has promoted the search for new therapies for treating American tegumentary leishmaniasis (ATL). In this study, BALB/c mice were injected in the hind paw with Leishmania (Leishmania) amazonensis and subsequently treated with a combination of nitric oxide (NO) donor (cis-[Ru(bpy) 2imN(NO)](PF6)3) (Ru-NO), given by intraperitoneal injection, and oral Brazilian propolis for 30 days. Ru-NO reached the center of the lesion and increased the NO level in the injured hind paw without lesion exacerbation. Histological and immunological parameters of chronic inflammation showed that this combined treatment increased the efficacy of macrophages, determined by the decrease in the number of parasitized cells, leading to reduced expression of proinflammatory and tissue damage markers. In addition, these drugs in combination fostered wound healing, enhanced the number of fibroblasts, pro-healing cytokines and induced collagen synthesis at the lesion site. Overall, our findings suggest that the combination of the NO donor Ru-NO and Brazilian propolis alleviates experimental ATL lesions, highlighting a new therapeutic option that can be considered for further in vivo investigations as a candidate for the treatment of cutaneous leishmaniasis.

Brazilian Propolis Antileishmanial and Immunomodulatory Effects

The antileishmanial and immunomodulatory effects of propolis collected in Botucatu, São Paulo State, Brazil, were evaluated in Leishmania (Viannia) braziliensis experimental infection. The antileishmanial effect of propolis on promastigote forms was verified by reducing growth and by promoting morphologic alterations observed by scanning electron microscopy. In in vitro immunomodulatory assays, macrophages were pretreated with propolis and then infected with L. (V.) braziliensis. In vivo, supernatants from liver cells and peritoneal exudate of BALB/c mice pretreated with propolis and infected with Leishmania (107/mL promastigotes) were collected, and TNF-α and IL-12 were measured by ELISA. Macrophages incubated with propolis showed a significant increase in interiorization and further killing of parasites. An increased TNF-α production was seen in mice pretreated with propolis, whereas IL-12 was downregulated during the infection. In conclusion, Brazilian propolis showed a direct action on the parasite and displayed immunomodulatory effects on murine macrophages, even though the parasite has been reported to affect the activation pathways of the cell. The observed effects could be associated with the presence of phenolic compounds (flavonoids, aromatic acids, and benzopyranes), di- and triterpenes, and essential oils found in our propolis sample.

Kaurenoic Acid Possesses Leishmanicidal Activity by Triggering a NLRP12/IL-1β/cNOS/NO Pathway.

Leishmania amazonensis (L. amazonensis) infection can cause severe local and diffuse injuries in humans, a condition clinically known as American cutaneous leishmaniasis (ACL). Currently, the therapeutic approach for ACL is based on Glucantime, which shows high toxicity and poor effectiveness. Therefore, ACL remains a neglected disease with limited options for treatment. Herein, the in vitro antiprotozoal effect and mechanisms of the diterpene kaurenoic acid [ent-kaur-16-en-19-oic acid] (KA) against L. amazonensis were investigated. KA exhibited a direct antileishmanial effect on L. amazonensis promastigotes. Importantly, KA also reduced the intracellular number of amastigote forms and percentage of infected peritoneal macrophages of BALB/c mice. Mechanistically, KA treatment reestablished the production of nitric oxide (NO) in a constitutive NO synthase- (cNOS-) dependent manner, subverting the NO-depleting escape mechanism of L. amazonensis. Furthermore, KA induced increased production of IL-1β and expression of the inflammasome-activating component NLRP12. These findings demonstrate the leishmanicidal capability of KA against L. amazonensis in macrophage culture by triggering a NLRP12/IL-1β/cNOS/NO mechanism.

Protective effect of metformin in an aberrant crypt foci model induced by 1,2-dimethylhydrazine: Modulation of oxidative stress and inflammatory process

Colorectal Cancer (CRC) is the third most frequent type of cancer worldwide. In the past few years, studies have revealed a protective effect of metformin (MET—an anti‐hyperglycemic drug, used to treat type 2 diabetes), against CRC. The protective effect of MET has been associated with AMPK activation (and mTOR inhibition), resulting in suppressed protein synthesis, and reduced cell proliferation in malignant transformed cells. To elucidate new mechanisms for the protective effect of metformin, we evaluated the oxidative stress and inflammatory process modulation, since these processes are strictly involved in colorectal carcinogenesis. The present study evaluated the protective effect of MET in a CRC model induced by 1,2‐dimethylhydrazine (DMH) in Balb/c female mice. The simultaneous/continuous treatment (administration of MET and DMH simultaneously), revealed protective activity of MET, preventing the formation of aberrant crypt foci (ACF) in 71.4% at distal colon sections, and was able to restore basal labeling of apoptosis. Treatment with MET also reduced the inflammatory process induced by DMH, resulting in of the reduction of oxidative stress and nitric oxide related parameters.

Brazilian propolis promotes immunomodulation on human cells from American Tegumentar Leishmaniasis patients and healthy donors infected with L. braziliensis

American Tegumentar Leishmaniasis (ATL) is an infectious disease caused by Leishmania parasites with ineffective treatment. The properties of propolis have been studied in different experimental studies, however, few works have investigated the effects of propolis on human-derived peripheral blood mononuclear cells (PBMC) in leishmaniasis models. Thus, we investigate the immunomodulatory effects of propolis treatment on PBMC from ATL patients and on PBMC from healthy donors infected with Leishmania braziliensis. Our data demonstrate that propolis pretreatment shows immunomodulatory effects on both healthy donors and ATL patients adherent cells, increasing IL-4 and IL-17 and decreasing IL-10, in either the presence or absence of the L. braziliensis infection, demonstrating that propolis contributes with the decrease of the inflammation and could also contribute with parasite control.

Pravastatin and simvastatin inhibit the adhesion, replication and proliferation of Toxoplasma gondii (RH strain) in HeLa cells.

The conventional treatment for toxoplasmosis with pyrimethamine and sulfadiazine shows toxic effects to the host, and it is therefore necessary to search for new drugs. Some studies suggest the use of statins, which inhibit cholesterol synthesis in humans and also the initial processes of isoprenoid biosynthesis in the parasite. Thus, the objective of this study was to evaluate the activity of the statins pravastatin and simvastatin in HeLa cells infected in vitro with the RH strain of T. gondii. HeLa cells (1×105) were infected with T. gondii tachyzoites (5×105) following two different treatment protocols. In the first protocol, T. gondii tachyzoites were pretreated with pravastatin (50 and 100μg/mL) and simvastatin (1.56 and 3.125μg/mL) for 30min prior to infection. In the second, HeLa cells were first infected (5×105) with tachyzoites and subsequently treated with pravastatin and simvastatin for 24h at the concentrations noted above. Initially, we evaluated the cytotoxicity of drugs by the MTT assay, number of tachyzoites adhered to cells, number of infected cells, and viability of tachyzoites by trypan blue exclusion. The supernatant of the cell cultures was collected post-treatment for determination of the pattern of Th1/Th2/Th17 cytokines by cytometric bead array. There was no cytotoxicity to HeLa cells with 50 and 100μg/mL pravastatin and 1.56 and 3.125μg/mL simvastatin. There was no change in the viability of tachyzoites that received pretreatment. Regarding the pre- and post-treatment of the cells with pravastatin and simvastatin alone, there was a reduction in adhesion, invasion and proliferation of cells to T. gondii. As for the production of cytokines, we found that IL-6 and IL-17 were significantly reduced in cells infected with T. gondii and treated with pravastatin and simvastatin, when compared to control. Based on these results, we can infer that pravastatin and simvastatin alone possess antiproliferative effects on tachyzoites forms of T. gondii, giving these drugs new therapeutic uses.

Glucantime reduces mechanical hyperalgesia in cutaneous leishmaniasis and complete Freund's adjuvant models of chronic inflammatory pain

To evaluate the analgesic effect of Glucantime (antimoniate N‐methylglucamine) in Leishmania amazonensis infection and complete Freunds adjuvant (CFA), chronic paw inflammation model, in BALB/c mice.

Concanavalin-A displays leishmanicidal activity by inducing ROS production in human peripheral blood mononuclear cells

Abstract The context of the article: Leishmania amazonensis has a wide geographical distribution throughout South American countries and can cause self-healing to severe cases as mucocutaneous or visceral forms. Leishmaniasis presents a balance of inflammatory and anti-inflammatory cytokines which is responsible for promoting the activation of phagocytes, essential to control the infection and lead to tissue repair/resolution of the disease, respectively. Results and discussion: Our model revealed that the treatment with Con-A was capable to stimulate human PBMC cells by increasing the phagocytic capacity and promoting parasite elimination. The pretreatment with Con-A promoted inflammatory (IFN-γ, TNF-α, IL-2 and IL-6) and anti-inflammatory (IL-4 and IL-10) cytokines production, increased the reactive oxygen species (ROS) sinthesys as well as the expression and presence of iNOS enzyme, but not nitric oxide production. Conclusion: Based on the data obtained, it was possible to infer that Con-A induces the ROS production, responsible for eliminating parasites in addition to regulatory cytokines synthesis which are important for disease resolution.

Interferon-gamma in mobilized stem cells: A possible prognostic marker in early post-transplant management in multiple myeloma

Introduction A complex network of cytokines in the bone marrow microenvironment has been implicated as an important factor in the pathogenesis of multiple myeloma (MM). Different cytokines have been studied in MM, both in peripheral blood and/or bone marrow, but there are few data correlating cytokines in leukapheresis product with post‐transplant response depth to treatment. Materials and Methods In a retrospective cross‐sectional study, levels of tumor necrosis factor alpha (TNF‐&agr;), transforming growth factor beta‐1 (TGF‐&bgr;1) and interferon gamma (IFN‐&ggr;) in peripheral hematopoietic stem cells/leukapheresis product (PHSC) of patients with MM eligible for transplantation were evaluated. Association of these cytokines with certain factors such as mobilized CD34 + cells/kg, staging, response to treatment and outcome were analyzed. Results The median baseline IFN‐&ggr; level was 826.4 pg/mL. IFN‐&ggr; levels in the leukapheresis product were significantly lower in patients who achieved complete response (CR) three months post‐transplant when compared to patients with very good partial response (VGPR) (674.75 ± 80.32 pg/mL versus 939.6 ± 106.8 pg/mL, p = 0.02), respectively. Patients who lost depth of response at the third‐month post‐transplant had a median level of IFN‐&ggr; 1133, being considered “high‐expressors” of IFN‐&ggr;, while those reaching improved response were called “low‐expressors” (median level IFN‐&ggr; 485 pg/mL). Overall and progression–free survival did not have a statistically significant correlation with TNF‐&agr;, TGF‐&bgr;1 or IFN‐&ggr;, as well as TNF‐&agr; and TGF‐&bgr;1 levels in post‐transplant response assessment. Conclusion IFN‐&ggr; in PHSC seems to be an important biomarker of loss of response in MM, suggesting a role in early post‐transplant therapeutic management.

Analysis of cytokines IFN-γ, TNF-α, TGF-β and nitric oxide in amniotic fluid and serum of pregnant women with toxoplasmosis in southern Brazil

HighlightsReduce proinflammatory biomarkers in infected pregnant women.High level of TGF‐&bgr; in pregnant women in the acute phase.Cytokines in the amniotic fluid (AF) were at levels similar to or lower than in those the blood.Nitric oxide in the AF was higher levels than in the blood.Absence of congenital transmission in pregnant women with acute toxoplasmosis. &NA; This study detected and compared the levels of IFN‐&ggr;, TNF‐&agr;, TGF‐&bgr; and nitric oxide (NO) in amniotic fluid (AF) and serum of pregnancies with acute toxoplasmosis, Southern Brazil. It also was compared the levels of the same mediators in the serum of pregnancies in acute and chronic toxoplasmosis with non‐infected. Serological investigation, anti‐T gondii IgM and IgG, of the 67 pregnancies was determined by Elisa MEIA. Forty two were uninfected, eight in chronic phase and 17 in acute phase. Among the acute phase, seven agreed to amniocentesis. The cytokines, in serum and in AF, were assessed by sandwich ELISA, and NO was estimated from the nitrite measurement with Griess reagent. The IFN‐&ggr; and TGF‐&bgr; levels in the AF and blood were similar, while TNF‐&agr; levels was lower in the AF. On the other hand, NO was higher in the AF. Chronically infected pregnant women have showed lower levels of INF‐&ggr; than those in acute and uninfected pregnancies. The serological levels of TNF‐&agr; were lower in pregnancies with toxoplasmosis, when compared with non‐infected. TGF‐&bgr; levels were higher in pregnancies in acute phase when compared with uninfected or chronically infected. NO in the serum of the infected had lower levels than those non‐infected. In summary, higher concentrations of NO and lower levels of TNF‐&agr; were observed in the AF than in the serum of acute pregnancies, while TGF‐&bgr; e INF‐&ggr; levels were similar in both biological material. In the serum of infected pregnancies was observed decrease in inflammatory mediators and increase of TGF‐&bgr;.