Insights into IL-33 on inflammatory response during in vitro infection by Trypanosoma cruzi.

Inflammatory and regulatory cytokines play an important role in the immunopathogenesis of Trypanosoma cruzi infection. Interleukin (IL)-33 is a member of the IL-1 superfamily of cytokines whose expression/production is upregulated following pro-inflammatory stimulation to alert the immune system in response to tissue stress or damage. The aim of this study was to evaluate the inflammatory profile induced in cultured J774 cells stimulated or not with IL-33 (10 ng/mL), with live parasites (1 × 106 metacyclic trypomastigote forms) and/or total antigen, TcAg (100 µg/mL) and with both, IL-33 and TcAg/T. cruzi. The cultures were evaluated at 24 h and 48 h after addition of the stimuli. For this, the supernatants were collected for the measurement of TNF, IL-17, CCL2, and IL-10 by ELISA and of nitrite by the Griess method. TNF, IL-17, and CCL2 concentrations were elevated in the presence of TcAg or live T. cruzi parasites at 24 h, and the addition of IL-33 potentiated these effects at 48 h. In addition, the T. cruzi-amastigote forms reduced in those infected J774 cells stimulated with IL-33 at 48 h. In conclusion, the IL-33 elevated the production of the TNF, IL-17, and CCL2 in cultured J774 cells stimulated with T. cruzi and/or its antigen and reduced the intracellular parasites, providing impetus to new investigations on its potential actions on the parasite-induced inflammation.

New Insights Into Blue Light Phototherapy in Experimental Trypanosoma cruzi Infection.

The search for an effective etiologic treatment to eliminate Trypanosoma cruzi, the causative agent of Chagas disease, has continued for decades and yielded controversial results. In the 1970s, nifurtimox and benznidazole were introduced for clinical assessment, but factors such as parasite resistance, high cellular toxicity, and efficacy in acute and chronic phases of the infection have been debated even today. This study proposes an innovative strategy to support the controlling of the T. cruzi using blue light phototherapy or blue light-emitting diode (LED) intervention. In in vitro assays, axenic cultures of Y and CL strains of T. cruzi were exposed to 460 nm and 40 µW/cm2 of blue light for 5 days (6 h/day), and parasite replication was evaluated daily. For in vivo experiments, C57BL6 mice were infected with the Y strain of T. cruzi and exposed to 460 nm and 7 µW/cm2 of blue light for 9 days (12 h/day). Parasite count in the blood and cardiac tissue was determined, and plasma interleukin (IL-6), tumoral necrosis factor (TNF), chemokine ligand 2 (CCL2), and IL-10 levels and the morphometry of the cardiac tissue were evaluated. Blue light induced a 50% reduction in T. cruzi (epimastigote forms) replication in vitro after 5 days of exposure. This blue light-mediated parasite control was also observed by the T. cruzi reduction in the blood (trypomastigote forms) and in the cardiac tissue (parasite DNA and amastigote nests) of infected mice. Phototherapy reduced plasma IL-6, TNF and IL-10, but not CCL2, levels in infected animals. This non-chemical therapy reduced the volume density of the heart stroma in the cardiac connective tissue but did not ameliorate the mouse myocarditis, maintaining a predominance of pericellular and perivascular mononuclear inflammatory infiltration with an increase in polymorphonuclear cells. Together, these data highlight, for the first time, the use of blue light therapy to control circulating and tissue forms of T. cruzi. Further investigation would demonstrate the application of this promising and potential complementary strategy for the treatment of Chagas disease.

Ectonucleotidases from trypomastigotes from different sources and various genetic backgrounds of Trypanosoma cruzi potentiate their infectivity and host inflammation.

Distinct populations of Trypanosoma cruzi interact with mammalian cardiac muscle cells causing different inflammation patterns and low heart functionality. During T. cruzi infection, the extracellular ATP is hydrolyzed to tri- and/or diphosphate nucleotides, based on the infectivity, virulence, and regulation of the inflammatory response. T. cruzi carries out this hydrolysis through the T. cruzi ectonucleotidase, NTPDase-1 (TcNTPDase-1). This study aimed to evaluate the role of TcNTPDase-1 in culture rich in metacyclic trypomastigote forms (MT) and cell culture-derived trypomastigote forms (CT) from Colombiana (discrete typing unit - DTU I), VL-10 (DTU II), and CL (DTU VI) strains of T. cruzi. For this, we measured TcNTPDase-1 activity in suramin-treated and untreated parasites and infected J774 cells and C57BL/6 mice with suramin pre-treated parasites to assess parasitic and inflammatory cardiac profile in the acute phase of infection. Our data indicated a higher TcNTPDase-1 activity for ATP in culture rich in metacyclic trypomastigote forms from Colombiana strain in comparison to those from VL-10 and CL strains. The cell culture-derived trypomastigote forms from CL strain presented higher capacity to hydrolyze ATP than those from Colombiana and VL-10 strains. Suramin inhibited ATP hydrolysis in all studied parasite forms and strains. Suramin pre-treated parasites reduced J774 cell infection and increased nitrite production in vitro. In vivo studies showed a reduction of inflammatory infiltrate in the cardiac tissues of animals infected with cell culture-derived trypomastigote forms from suramin pre-treated Colombiana strain. In conclusion, TcNTPDase-1 activity in trypomastigotes forms drives part of the biological characteristics observed in distinct DTUs and may induce cardiac pathogenesis during T. cruzi infection.

A High-Fat Diet Exacerbates the Course of Experimental Trypanosoma cruzi Infection That Can Be Mitigated by Treatment with Simvastatin.

The protozoan Trypanosoma cruzi is responsible for triggering a damage immune response in the host cardiovascular system. This parasite has a high affinity for host lipoproteins and uses the low-density lipoprotein (LDL) receptor for its invasion. Assuming that the presence of LDL cholesterol in tissues could facilitate T. cruzi proliferation, dietary composition may affect the parasite-host relationship. Therefore, the aim of this study was to evaluate myocarditis in T. cruzi-infected C57BL/6 mice-acute phase-fed a high-fat diet and treated with simvastatin, a lipid-lowering medication. Animals (n = 10) were infected with 5 × 103 cells of the VL-10 strain of T. cruzi and treated or untreated daily with 20 mg/kg simvastatin, starting 24 h after infection and fed with a normolipidic or high-fat diet. Also, uninfected mice, treated or not with simvastatin and fed with normolipidic or high-fat diet, were evaluated as control groups. Analyses to measure the production of chemokine (C-C motif) ligand 2 (CCL2), interferon- (IFN-) γ, interleukin- (IL-) 10, and tumor necrosis factor (TNF); total hepatic lipid dosage; cholesterol; and fractions, as well as histopathological analysis, were performed on day 30 using cardiac and fat tissues. Our results showed that the high-fat diet increased (i) parasite replication, (ii) fat accumulation in the liver, (iii) total cholesterol and LDL levels, and (iv) the host inflammatory state through the production of the cytokine TNF. However, simvastatin only reduced the production of CCL2 but not that of other inflammatory mediators or biochemical parameters. Together, our data suggest that the high-fat diet may have worsened the biochemical parameters of the uninfected and T. cruzi-infected animals, as well as favored the survival of circulating parasites.

Combination therapy with benznidazole and doxycycline shows no additive effect to monotherapy with benznidazole in mice infected with the VL-10 strain of the Trypanosoma cruzi.

BACKGROUND: Chagas heart disease is the most important clinical manifestation of Trypanosoma cruzi infection. Pharmacological therapies have been proposed aiming to reduce inflammatory response and cardiac damage in infected hosts. In this study, we investigated the use of doxycycline (Dox), in a sub-antimicrobial dose, in monotherapy and in combination with benznidazole (Bz) during the acute phase of infection with the VL-10 strain of T. cruzi, evaluating the therapeutic effect during the acute and chronic phases of the infection. METHODS AND RESULTS: C57BL/6 mice were treated for 20 days with Dox (30 mg/kg), Bz (100 mg/kg), or both drugs in combination starting 9 days after infection. Parasitemia was measured during the acute phase and the animals were monitored for 12 months, after which echocardiography analysis was performed. Blood samples were obtained from euthanized mice for CCL2, CCL5, IL-10 analysis, and cardiac fragments were collected for histopathological evaluation. Dox treatment did not ameliorate parasitological/inflammatory parameters but reduced the cardiac collagen neoformation (CN) in 35%. In contrast, Bz administration reduced parasitemia, plasma levels of CCL2 and CCL5, and cardiac infiltration during acute infection, and reduced the level of IL-10 and CN (95%) at 12 months. Dox was unable to improve ejection fraction, while Bz treatment ameliorated the ejection fraction. No additive effect was observed in combination therapy. CONCLUSION: Dox monotherapy is not effective in the acute or chronic phases of experimental cardiomyopathy induced by the VL-10 strain of T. cruzi. Furthermore, combination therapy with Dox does not potentiate the effects of Bz monotherapy.

The ß-blocker carvedilol and the benznidazole modulate the cardiac immune response in the acute infection induced by Colombian strain of the Trypanosoma cruzi.

BACKGROUND The infection led by Trypanosoma cruzi persists in mammalian tissues causing an inflammatory imbalance. Carvedilol (Cv), a non-selective beta blocker drug indicated to treat heart failure and antihypertensive has shown to promote antioxidant and immunomodulatory properties which might improve the inflammation induced by T. cruzi. OBJECTIVES Evaluate the role of Cv on the inflammatory response of C57BL/6 mice acutely infected with the Colombian strain of T. cruzi. METHODS Animals were infected with the Colombian strain of T. cruzi and treated with Cv (25 mg/kg/day), benznidazole (Bz) (100 mg/kg/day) or their combination. On the 28th day of infection and 23 days of treatment, the euthanasia occurred, and the heart preserved for histopathological, oxidative stress (SOD, catalase, TBARs, carbonylated proteins) and plasma (CCL2, CCL5, TNF, IL-10) analyses. Parasitaemia and survival were assessed along the infection. FINDINGS Cv decreased TBARs, but increased the mortality rate, the parasitaemia and the levels of CCL2, CCL5, catalase and the inflammatory infiltrate in the cardiac tissue. Bz led the reduction of the inflammatory infiltrate and circulating levels of oxidative stress and inflammatory mediators in the infected mice. MAIN CONCLUSIONS Our data suggest that Cv, in this experimental model using the Colombian strain of T. cruzi, caused damage to the host.

The overweight increases circulating inflammatory mediators commonly associated with obesity in young individuals.

Obesity is a serious and growing world healthy problem affecting developed and developing countries. The new conception of obesity as a basal inflammatory condition has opened a new window of possibilities to identify inflammatory biomarkers to be used in the diagnosis or prognosis of obesity-associated comorbidities. This present work aims the identification of the adipokines (leptin and resistin), chemokines (CCL2, CCL5, CXCL16) and the BMP-2 and their association with the clinical, biochemical (fasting glucose, hemogram, cholesterol, T3, T4 and TSH) and anthropometric (weight, height, body circumferences, skinfold thickness and percentage of body fat) parameters in young adults (18-30 years old) presenting obesity and overweight. Our data showed increasing in anthropometric parameters and in the plasma inflammatory levels in those individuals presenting overweight and obesity. We observed a higher plasma levels of CCL2, CCL5, CXCL16, leptin and resistin in those overweigh and obese individuals. In addition, the CCL2, CCL5 presented a positive correlation with the body mass index and the body fat percentage. Assuming the obesity as a systemic inflammatory process, in this current study, the overweight individuals possess a close similar pattern of circulating inflammatory mediators which might be a potential risk of the development of obesity comorbidities. Further studies are still needed to precise the role of the biomarkers CCL2, CCL5, CXCL16 and BMP-2 in the clinical prognosis related to the overweight or obese individuals.

The B-blocker carvedilol and the benznidazole modulate the cardiac immune response in the acute infection induced by Colombian strain of the Trypanosoma cruzi

BACKGROUND The infection led by Trypanosoma cruzi persists in mammalian tissues causing an inflammatory imbalance. Carvedilol (Cv), a non-selective beta blocker drug indicated to treat heart failure and antihypertensive has shown to promote antioxidant and immunomodulatory properties which might improve the inflammation induced by T. cruzi. OBJECTIVES Evaluate the role of Cv on the inflammatory response of C57BL/6 mice acutely infected with the Colombian strain of T. cruzi. METHODS Animals were infected with the Colombian strain of T. cruzi and treated with Cv (25 mg/kg/day), benznidazole (Bz) (100 mg/kg/day) or their combination. On the 28th day of infection and 23 days of treatment, the euthanasia occurred, and the heart preserved for histopathological, oxidative stress (SOD, catalase, TBARs, carbonylated proteins) and plasma (CCL2, CCL5, TNF, IL-10) analyses. Parasitaemia and survival were assessed along the infection. FINDINGS Cv decreased TBARs, but increased the mortality rate, the parasitaemia and the levels of CCL2, CCL5, catalase and the inflammatory infiltrate in the cardiac tissue. Bz led the reduction of the inflammatory infiltrate and circulating levels of oxidative stress and inflammatory mediators in the infected mice. MAIN CONCLUSIONS Our data suggest that Cv, in this experimental model using the Colombian strain of T. cruzi, caused damage to the host.

The immunomodulatory effects of the Enalapril in combination with Benznidazole during acute and chronic phases of the experimental infection with Trypanosoma cruzi.

Trypanosoma cruzi infection triggers a chronic inflammatory process responsible for the alterations in the extracellular matrix and functionality of the heart. The angiotensin converting enzyme (ACE) inhibitors affects T. cruzi in vitro surveillance and modulates in vivo some inflammatory mediators. In this study, we investigated the treatment with an ACE inhibitor (Enalapril) and the Benznidazole (Bz) in a single and combination therapies (CT) in C57BL/6 mice infected with VL-10 strain of the T. cruzi. Animals were treated during 20days with different doses of Bz (100, 80, 60mg/kg), Enalapril (25, 20, 15mg/kg) and their CT (100+25; 80+20; 60+15mg/kg) and euthanized at 30° (acute) and at 120° (chronic) days post infection. The plasma and heart were processed for immunopathological investigations. Our data shown that Bz and Enalapril controlled, in part, the parasite replication and reduced plasma levels of TNF, CCL2 and CCL5 in the acute and in chronic phase of infection. However, the CT doses reduced in around 20% the inflammatory parameters obtained with the Bz therapy. The CT doses of 100+25 and 80+20mg/kg increased the IL-10 levels and reduced the cardiac inflammation while Bz inhibited the collagen neogenesis in the infection. In conclusion, we assume that the CT administrated in the initial stage of infection, presents a minor immunomodulatory effect when the VL-10 strain of T. cruzi is used. In contrast, Bz and Enalapril in monotherapies persist suggesting a potential protection against cardiac damages during experimental T. cruzi infection.

Potential Role of Carvedilol in the Cardiac Immune Response Induced by Experimental Infection with Trypanosoma cruzi.

Trypanosoma cruzi causes a cardiac infection characterized by an inflammatory imbalance that could become the inciting factor of the illness. To this end, we evaluated the role of carvedilol, a beta-blocker with potential immunomodulatory properties, on the immune response in C57BL/6 mice infected with VL-10 strain of T. cruzi in the acute phase. Animals (n = 40) were grouped: (i) not infected, (ii) infected, (iii) infected + carvedilol, and (iv) not infected + carvedilol. We analyzed parameters related to parasitemia, plasma levels of TNF, IL-10, and CCL2, and cardiac histopathology after the administration of carvedilol for 30 days. We did not observe differences in the maximum peaks of parasitemia in the day of their detection among the groups. The plasma TNF was elevated at 60 days of infection in mice treated or not with carvedilol. However, we observed a decreased CCL2 level and increased IL-10 levels in those infected animals treated with carvedilol, which impacted the reduction of the inflammatory infiltration in cardiac tissue. For this experimental model, carvedilol therapy was not able to alter the levels of circulating parasites but modulates the pattern of CCL2 and IL-10 mediators when the VL10 strain of T. cruzi was used in C57BL6 mice.