CCL3, a member of the CC-chemokine family, has been associated with macrophage recruitment to heart tissue and parasite control in the acute infection of mouse with
, the causative agent of Chagas ...disease. Here, we approached the participation of CCL3 in chronic chagasic cardiomyopathy (CCC), the main clinical form of Chagas disease. We induced CCC in C57BL/6 (
3
) and CCL3-deficient (
3
) mice by infection with the Colombian Type I strain. In
3
mice, high levels of CCL3 mRNA and protein were detected in the heart tissue during the acute and chronic infection. Survival was not affected by CCL3 deficiency. In comparison with
3
, chronically infected
3
mice presented reduced cardiac parasitism and inflammation due to CD8
cells and macrophages. Leukocytosis was decreased in infected
3
mice, paralleling the accumulation of CD8
T cells devoid of activated CCR5
LFA-1
cells in the spleen. Further,
-infected
3
mice presented reduced frequency of interferon-gamma (IFNγ)
cells and numbers of parasite-specific IFNγ-producing cells, while the
antigen-specific cytotoxic activity was increased. Stimulation of CCL3-deficient macrophages with IFNγ improved parasite control, in a milieu with reduced nitric oxide (NO
) and tumor necrosis factor (TNF), but similar interleukin-10 (IL-10), concentrations. In comparison with chronically
-infected
3
counterparts,
3
mice did not show enlarged heart, loss of left ventricular ejection fraction, QTc prolongation and elevated CK-MB activity. Compared with
3
, infected
3
mice showed reduced concentrations of TNF, while IL-10 levels were not affected, in the heart milieu. In spleen of
3
NI controls, most of the CD8
T-cells expressing the CCL3 receptors CCR1 or CCR5 were IL-10
, while in infected mice these cells were mainly TNF
. Lastly, selective blockage of CCR1/CCR5 (Met-RANTES therapy) in chronically infected
3
mice reversed pivotal electrical abnormalities (bradycardia, prolonged PR, and QTc interval), in correlation with reduced TNF and, mainly, CCL3 levels in the heart tissue. Therefore, in the chronic
infection CCL3 takes part in parasite persistence and contributes to form a CD8
T-cell and macrophage-enriched cardiac inflammation. Further, increased levels of CCL3 create a scenario with abundant IFNγ and TNF, associated with cardiomyocyte injury, heart dysfunction and QTc prolongation, biomarkers of severity of Chagas' heart disease.
Toxoplasmosis is a globally significant disease that poses a severe threat to immunocompromised individuals, especially in Brazil, where a high prevalence of virulent and atypical strains of ...Toxoplasma gondii is observed. In 1998, the EGS strain, exhibiting a unique infection phenotype, was isolated in Brazil, adding to the complexity of strain diversity. The P2X7 receptor is critical in inflammation and controlling intracellular microorganisms such as T. gondii. However, its genetic variability can result in receptor dysfunction, potentially worsening susceptibility. This study investigates the role of the P2X7 receptor during acute infection induced by the EGS atypical strain, offering insight into the mechanisms of T. gondii infection in this context. We infected the female C57BL/6 (WT) or P2X7 knockout (P2X7 −/− ) by gavage. The EGS infection causes intestinal inflammation. The P2X7 −/− mice presented higher parasite load in the intestine, spleen, and liver. The absence of the P2X7 receptor disrupts inflammatory cell balance by reducing NLRP3, IL-1β, and Foxp3 expression while increasing IFN-γ expression and production in the intestine. In the liver, P2X7 -/- animals demonstrate diminished inflammatory infiltrate within the portal and lobular regions concurrent with an enlargement of the spleen. In conclusion, the infection of mice with the EGS strain elicited immune alterations, leading to acute inflammation and cytokine dysregulation, while the P2X7 receptor conferred protection against parasitic proliferation across multiple organs.
This study aimed to investigate the pathophysiology of hepatic microcirculatory dysfunction in non-alcoholic fatty liver disease (NAFLD).
In Wistar rats, NAFLD model was induced by 20 weeks of ...high-fat diet (HFD) feeding. Rolling and adhesion of leukocytes and tissue perfusion in hepatic microcirculation were examined using in vivo microscopic and laser speckle contrast imaging (LSCI), respectively. Oxidative stress and inflamatory parameters were analysed by TBARs, catalase enzyme activity, RT-PCR and ELISA. The participation of advanced glycation end-products (AGE) and its receptor RAGE was evaluated by the measurement of gene and protein expression of RAGE by RT-PCR and Western-blot, respectively and by liver and serum quantification of fluorescent AGEs.
Wistar rats fed high-fat diet (HFD) showed increase in epididymal and abdominal fat content, systolic arterial blood pressure, fasting blood glucose levels, hepatic triglycerides and cholesterol, and impairment of glucose and insulin metabolisms. Liver histology confirmed the presence of steatosis and ultrasound analysis revealed increased liver size and parenchymal echogenicity in HFD-fed rats. HFD causes significant increases in leukocyte rolling and adhesion on hepatic microcirculation and decrease in liver microvascular blood flow. Liver tissue presented increase in oxidative stress and inflammtion. At 20 weeks, there was a significantly increase in AGE content in the liver and serum of HFD-fed rats and an increase in RAGE gene expression in the liver.
The increase in liver AGE levels and microcirculatory disturbances could play a role in the pathogenesis of liver injury and are key components of NAFLD.
Chagasic chronic cardiomyopathy (CCC) is the primary clinical manifestation of Chagas disease (CD), caused by Trypanosoma cruzi. Current therapeutic options for CD are limited to benznidazole (Bz) ...and nifurtimox. Amiodarone (AMD) has emerged as most effective drug for treating the arrhythmic form of CCC. To address the effects of Bz and AMD we used a preclinical model of CCC. Female C57BL/6 mice were infected with T. cruzi and subjected to oral treatment for 30 consecutive days, either as monotherapy or in combination. AMD in monotherapy decreased the prolonged QTc interval, the incidence of atrioventricular conduction disorders and cardiac hypertrophy. However, AMD monotherapy did not impact parasitemia, parasite load, TNF concentration and production of reactive oxygen species (ROS) in cardiac tissue. Alike Bz therapy, the combination of Bz and AMD (Bz/AMD), improved cardiac electric abnormalities detected T. cruzi-infected mice such as decrease in heart rates, enlargement of PR and QTc intervals and increased incidence of atrioventricular block and sinus arrhythmia. Further, Bz/AMD therapy ameliorated the ventricular function and reduced parasite burden in the cardiac tissue and parasitemia to a degree comparable to Bz monotherapy. Importantly, Bz/AMD treatment efficiently reduced TNF concentration in the cardiac tissue and plasma and had beneficial effects on immunological abnormalities. Moreover, in the cardiac tissue Bz/AMD therapy reduced fibronectin and collagen deposition, mitochondrial damage and production of ROS, and improved sarcomeric and gap junction integrity. Our study underlines the potential of the Bz/AMD therapy, as we have shown that combination increased efficacy in the treatment of CCC.
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To investigate the effects of moderate aerobic physical training on cardiac function and morphology as well as on the levels of glial cell-derived neurotrophic factor (GDNF), nerve growth factor ...(NGF) and brain derived neurotrophic factor (BDNF) of animals infected with the Y strain of Trypanosoma cruzi.
Twenty-eight male C57BL/6 mice were distributed into 4 groups: sedentary control (SC), trained control (TC), sedentary infected (CHC) and trained infected (CHT). The infection was performed by intraperitoneal injection of trypomastigote forms and the animals were adapted to treadmill in the week before the beginning of the training protocol, initiated 45 days post infection. Maximal exercise test (TEM) was performed at the baseline as well as at the end of the 4th, 8th and 12th weeks of training. At the end of the 12th week, all animals were evaluated for cardiac morphology and function by echocardiography.
CHC group showed a larger area of right ventricle (RVA), increased end-systolic volume and reduction in ejection fraction (EF), stroke volume (SV), cardiac output (CO) and fractional area change (FAC). The training reduced the RVA and improved the FAC of chagasic animals. GDNF level was higher in TC and CHC groups compared to SC in heart and BDNF levels were higher in CHC compared to SC in heart and serum.
Physical training ameliorated the cardiac function of infected animals and promoted adjusts in BDNF and GDNF levels. These findings evidenced these neurotrophins as possible biomarkers of cardiac function responsive to exercise stimulus.
Chronic chagasic cardiomyopathy (CCC), the main clinical sign of Chagas disease, is associated with systemic CD8+ T-cell abnormalities and CD8-enriched myocarditis occurring in an inflammatory ...milieu. Pentoxifylline (PTX), a phosphodiesterase inhibitor, has immunoregulatory and cardioprotective properties. Here, we tested PTX effects on CD8+ T-cell abnormalities and cardiac alterations using a model of experimental Chagas' heart disease.
C57BL/6 mice chronically infected by the Colombian Trypanosoma cruzi strain and presenting signs of CCC were treated with PTX. The downmodulation of T-cell receptors on CD8+ cells induced by T. cruzi infection was rescued by PTX therapy. Also, PTX reduced the frequency of CD8+ T-cells expressing activation and migration markers in the spleen and the activation of blood vessel endothelial cells and the intensity of inflammation in the heart tissue. Although preserved interferon-gamma production systemically and in the cardiac tissue, PTX therapy reduced the number of perforin+ cells invading this tissue. PTX did not alter parasite load, but hampered the progression of heart injury, improving connexin 43 expression and decreasing fibronectin overdeposition. Further, PTX reversed electrical abnormalities as bradycardia and prolonged PR, QTc and QRS intervals in chronically infected mice. Moreover, PTX therapy improved heart remodeling since reduced left ventricular (LV) hypertrophy and restored the decreased LV ejection fraction.
PTX therapy ameliorates critical aspects of CCC and repositioned CD8+ T-cell response towards homeostasis, reinforcing that immunological abnormalities are crucially linked, as cause or effect, to CCC. Therefore, PTX emerges as a candidate to treat the non-beneficial immune deregulation associated with chronic Chagas' heart disease and to improve prognosis.
Tissue factor (TF), a blood coagulation protein, plays an important role in tumor growth, invasion, and metastasis. Ixolaris, a tick-derived non-immunogenic molecule that binds to TF, has ...demonstrated in vivo inhibitory effect on murine models of melanoma, including primary growth and metastasis. This work aimed to: I) develop an efficient and stable labeling technique of ixolaris with Iodine-131(
131
I); II) compare the biodistribution of
131
I and
131
I-ixolaris in tumor-free and melanoma-bearing mice; III) evaluate whether
131
I-ixolaris could serve as an antimetastatic agent. Ixolaris radioiodination was performed using iodogen, followed by liquid paper chromatography. Labeling stability and anticoagulant activity were measured. Imaging studies were performed after intravenous administration of free
131
I or
131
I-ixolaris in a murine melanoma model employing the B16-F10 cell line. Animals were divided in three experimental groups: the first experimental group, D0, received a single-dose of 9.25 MBq of
131
I-ixolaris at the same day the animals were inoculated with melanoma cells. In the second group, D15, a single-dose of 9.25 MBq of
131
I-ixolaris or free
131
I was applied into mice on the fifteenth day after the tumor induction. The third group, D1-D15, received two therapeutic doses of 9.25 MBq of
131
I-ixolaris or
131
I. In vitro studies demonstrated that
131
I-ixolaris is stable for up to 24 h and retains its inhibitory activity on blood coagulation. Biodistribution analysis and metastasis assays showed that all treatment regimens with
131
I-ixolaris were effective, being the double-treatment (D1/D15) the most effective one. Remarkably, treatment with free
131
I showed no anti-metastatic effect.
131
I-ixolaris is a promising theranostic agent for metastatic melanoma.
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.
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.
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.
•Dox was unable to improve ejection fraction in T. cruzi (VL-10 strain)-infected mice.•Dox did not ameliorate immune-parasitological parameters in T. cruzi-infected mice.•Benznidazole ameliorated ejection fraction in T. cruzi (VL-10 strain)-infected mice.•Benznidazole reduced parasitemia, CCL2/CCL5 plasma levels and cardiac infiltration.•Combination therapy with Dox does not potentiate the effects of benznidazole.
Chagas disease (CD), caused by the protozoan
, is a neglected tropical disease and a health problem in Latin America. Etiological treatment has limited effectiveness in chronic CD; thus, new ...therapeutic strategies are required. The practice of physical exercises has been widely advocated to improve the quality of life of CD patients. The most frequent clinical CD manifestation is the chronic indeterminate form (CIF), and the effect of physical exercises on disease progression remains unknown. Here, in a CIF model, we aimed to evaluate the effect of physical exercises on cardiac histological, parasitological, mitochondrial, and oxidative metabolism, electro and echocardiographic profiles, and immunological features. To establish a CIF model, BALB/c and C57BL/6 mice were infected with 100 and 500 trypomastigotes of the Y
strain. At 120 days postinfection (dpi), all mouse groups showed normal PR and corrected QT intervals and QRS complexes. Compared to BALB/c mice, C57BL/6 mice showed a lower parasitemia peak, mortality rate, and less intense myocarditis. Thus, C57BL/6 mice infected with 500 parasites were used for subsequent analyses. At 120 dpi, a decrease in cardiac mitochondrial oxygen consumption and an increase in reactive oxygen species (ROS) were detected. When we increased the number of analyzed mice, a reduced heart rate and slightly prolonged corrected QT intervals were detected, at 120 and 150 dpi, which were then normalized at 180 dpi, thus characterizing the CIF. Y-infected mice were subjected to an exercise program on a treadmill for 4 weeks (from 150 to 180 dpi), five times per week in a 30-60-min daily training session. At 180 dpi, no alterations were detected in cardiac mitochondrial and oxidative metabolism, which were not affected by physical exercises, although ROS production increased. At 120 and 180 dpi, comparing infected and non-infected mice, no differences were observed in the levels of plasma cytokines, indicating that a crucial biomarker of the systemic inflammatory profile was absent and not affected by exercise. Compared with sedentary mice, trained Y-infected mice showed similar parasite loads and inflammatory cells but reduced cardiac fibrosis. Therefore, our data show that physical exercises promote beneficial changes that may prevent CD progression.
The present study demonstrated the potential effects of diethylcarbamazine (DEC) on monocrotaline (MCT)-induced pulmonary hypertension. MCT solution (600mg/kg) was administered once per week, and ...50mg/kg body weight of DEC for 28days. Three C57Bl/6 male mice groups (n=10) were studied: Control; MCT28, and MCT28/DEC. Echocardiography analysis was performed and lung tissues were collected for light microscopy (hematoxylin-eosin and Masson's trichrome staining), immunohistochemistry (αSMA, FADD, caspase 8, caspase 3, BAX, BCL2, cytochrome C and caspase 9) western blot (FADD, caspase 8, caspase 3, BAX, BCL2, cytochrome C and caspase 9) and qRt-PCR (COL-1α and αSMA). Echocardiography analysis demonstrated an increase in the pulmonary arterial blood flow gradient and velocity in the systole and RV area in the MCT28 group, while treatment with DEC resulted in a significant reduction in these parameters. Deposition of collagen fibers and αSMA staining around the pulmonary arteries was evident in the MCT28 group, while treatment with DEC reduced both. Western blot analysis revealed a decrease in BMPR2 in the MCT28 group, in contrast DEC treatment resulted in a significant increase in the level of BMPR2. DEC also significantly reduced the level of VEGF compared to the MCT28 group. Apoptosis extrinsic and intrinsic pathway markers were reduced in the MCT28 group. After treatment with DEC these levels returned to baseline. The results of this study indicate that DEC attenuates PH in an experimental monocrotaline-induced model by inhibiting a series of markers involved in cell proliferation/death.
•First study on the therapeutic effects of diethylcarbamazine in lung hypertension•Lung hypertension exhibited reductions apoptosis extrinsic and intrinsic pathways.•Diethylcarbamazine inhibited markers involved in cell proliferation/death.
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