Istradefylline induces A2A/P2X7 crosstalk expression inducing pro-inflammatory signal, and reduces AKT/mTOR signaling in melanoma-bearing mice.

ATP and adenosine (ADO) are critical players in the context of cancer. In the tumor microenvironment, the signaling dependent on these molecules, and immune cells, is regulated by an enzymatic chain and purinergic receptors called purinome. Primarily, the A2A receptor (A2AR) has a pro-tumor action since it reduces the immune response and favors the growth of malignant melanoma. Therefore, this study aimed to verify the effects of A2AR antagonism with Istradefylline (IST) on the purinergic signaling profile of the melanoma tumor and immunological compartments. We observed reduced tumor growth of melanoma in IST-treated animals. IST inhibited AKT/mTOR pathway, which is involved with tumor growth. In the tumor, spleen, and thymus, the modulation of purinergic enzymes (CD39, CD73, and E-ADA) characterized a pro-inflammatory profile since it favored increased extracellular concentrations of ATP to the detriment of ADO. A2AR inhibition generated a compensatory feedback process with increased A2AR expression at the tumor level. However, there was also an increase in the expression of the P2X7 receptor (P2X7R), which culminated in an increase in pro-inflammatory pathways with the release of IL-1ß and pro-inflammatory cytokines such as IFN-γ and TNF-α. Our data evidence the cross-involvement between expression and action of the A2AR and P2X7R. We suggest that IST is a promising drug for off-label use in cancer since it promotes an anti-tumoral response by producing pro-inflammatory cytokines and blocking of AKT/mTOR tumor growth pathway.

Distinct kinetics for nucleotide hydrolysis in lymphocytes isolated from blood, spleen and cervical lymph nodes: Characterization of ectonucleotidase activity.

Ectonucleotidases are a plasma membrane-bound enzyme that hydrolyses extracellular adenosine triphosphate (eATP) and adenosine diphosphate (eADP) to adenosine monophosphate (AMP). It regulates normal function of lymphocytes, acts as an inflammatory marker and represents a molecular target for new therapeutics. Thus, this study sought to isolate lymphocytes from blood (BL), spleen (SL) and cervical lymph node (CLL), and characterize the eATP and eADP enzymatic hydrolysis in Wistar rats. The hydrolysis of the nucleotides occurred primarily at pH 8.0, 37°C in the presence of Ca2+ or Mg2+ . Chevillard-plot showed the hydrolysis of eATP and eADP at the same active site. The inhibitors of some classical ATDPases did not cause any significant change on enzymatic activity. Inhibitors of E-NTPDase (-1, -2, -3 isoforms) and E-NPP-1 decrease the enzyme activity in all resident lymphocytes. Furthermore, kinetic parameters (Vmax and Km) revealed that SL had significantly (P < .001) higher enzymatic activity when compared to BL and CLL. In conclusion, this study standardized kinetic values for eATP and eADP hydrolysis for resident lymphocytes isolated from BL, SL and CLL.

Lipotoxicity-associated inflammation is prevented by guarana (Paullinia cupana) in a model of hyperlipidemia.

Hyperlipidemia causes lipotoxicity which prompts an inflammatory response linked to the development of cardiovascular diseases. Natural compounds have been receiving special attention for its potential to treat diseases, inexpensiveness, and safety. Guarana (Paullinia cupana) has demonstrated notable anti-inflammatory and antioxidant effects, which may prevent chronic diseases caused by changes in lipid profile. Thus, this study aims to evaluate the effect of guarana powder (Paullinia cupana) in the purine metabolism and inflammatory profile in lymphocytes and serum of rats with Poloxamer-407-induced hyperlipidemia. Pretreatment with guarana 12.5, 25, and 50 mg/kg/day or caffeine (0.2 mg/kg/day) by gavage was applied to adult male Wistar rats for a period of 30 days. As a comparative standard, we used simvastatin (0.04 mg/kg) post-induction. Hyperlipidemia was acutely induced with intraperitoneally injection of Poloxamer-407 (500 mg/kg). Guarana powder and caffeine increased the activity of the E-NTPDase (ecto-apyrase), and all pretreatments decreased the E-ADA (ecto-adenosine deaminase) activity, reducing the inflammatory process caused by lipotoxicity. In hyperlipidemic rats, ATP levels were increased while adenosine levels were decreased, guarana and caffeine reverted these changes. Guarana powder, caffeine, and simvastatin also prevented the increase in INF-γ and potentiated the increase in IL-4 levels, promoting an anti-inflammatory profile. Guarana promoted a more robust effect than caffeine. Our results show that guarana powder and caffeine have an anti-inflammatory as seen by the shift from a proinflammatory to an anti-inflammatory profile. The effects of guarana were more pronounced, suggesting that guarana powder may be used as a complementary therapy to improve the lipotoxicity-associated inflammation.

Uncaria tomentosa improves cognition, memory and learning in middle-aged rats.

Aging accelerates neurodegeneration, while natural and safe neuroprotective agents, such as Uncaria tomentosa, may help to overcome this problem. This study assessed the effects of U. tomentosa extract treatment on the aging process in the brain of Wistar rats. The spatial memory and learning, acetylcholinesterase (AChE) activity, and DNA damage were assessed. Animals of 14 months were tested with different doses of U. tomentosa (5 mg/kg, 15 mg/kg, and 30 mg/kg) and with different durations of treatment (one month and one year). In the Morris Water Maze (MWM), the escape latency was significantly (p < 0.0001) shorter in rats that received 5 mg/kg, 15 mg/kg, and 30 mg/kg of U. tomentosa for both one month and one year of treatment. There was a significant difference in time spent at the platform zone (p < 0.05) of the middle-aged rats treated with U. tomentosa extract for one year when compared to the control rats. The cortex and hippocampus of rats treated with U. tomentosa for one year showed significant (p > 0.05) reduction in AChE activity. DNA damage index on cortex was significantly lower (p < 0.05) in animals treated with 30 mg/kg of U. tomentosa for one month while all the tested doses demonstrated significant (p < 0.001) reductions in DNA damage index in animals treated for one year. In conclusion, U. tomentosa may represent a source of phytochemicals that could enhance memory activity, repair DNA damage, and alter AChE activity, thereby providing neuroprotection during the aging process.

CD4/CD8 ratio, comorbidities, and aging in treated HIV infected individuals on viral suppression.

The progression of the human immunodeficiency virus (HIV) infection to acquired immunodeficiency syndrome (AIDS) can be efficiently interrupted by antiretroviral therapy (ART). However, even successfully treated HIV-infected individuals are prone to develop non-AIDS-related diseases that affect the metabolism and several organs and systems. Biomarkers that predict the occurrence of comorbidities may help develop preventive measures. Current research shows that CD4+ T cell counts and viral load do not predict the development of non-AIDS-related diseases. The CD4/CD8 ratio has been indicated as a suitable marker of persistent immune dysfunction and the occurrence of non-AIDS-related events in treated HIV-positive patients. In this study, we explored the relationship between CD4/CD8 ratios, comorbidities, and aging in ART-treated HIV patients on viral suppression. We collected and evaluated data from 352 HIV-positive adults who were virologically suppressed (<40 copies/mL) on ART and with CD4 counts above 350 cells/mm3 . The median age for participants was 46 years, 218 individuals had at least one comorbidity, and 239 had inverted CD4/CD8 ratios (<1). Current CD4/CD8 ratios were predicted by baseline CD4/CD8 ratios and nadir CD4 counts. Despite the high rates of inverted CD4/CD8 ratios and prevalence of comorbidities, no association between them was observed. The prevalence of comorbidities was significantly higher in older individuals, though aging alone did not explain the rate of all individual comorbidities. Low CD4/CD8 ratios were linked to neurocognitive disorders, suggesting that persistent T cell dysfunction contributes to neurocognitive decline.

Hyperlipidemia-induced lipotoxicity and immune activation in rats are prevented by curcumin and rutin.

We assessed the effects of curcumin, rutin, and the association of rutin and curcumin in organs of hyperlipidemic rats. Rutin and curcumin have notable antioxidant and anti-inflammatory actions, so we hypothesized that their association would enhance their beneficial effects. Hyperlipidemia results in lipotoxicity and affects several organs. Lipotoxicity is not only an outcome of lipid accumulation in non-adipose tissues but also a result of the hyperlipidemia-associated inflammation and oxidative stress. Wistar rats were treated with rutin and curcumin for 30 days before the induction of acute hyperlipidemia by Poloxamer-407. After 36 h, the animals were euthanized for collection of blood and organs. Untreated hyperlipidemic rats showed higher uric acid and albumin levels in the serum and increased spleen size and ADA activity. Rutin, curcumin and the association reduced the spleen size by 20% and ADA activity by 23, 28, and 27%, respectively. Rats pretreated with rutin showed reduced lipid damage in the liver (40%) and the kidney (44%), and the protein damage was also reduced in the liver (75%). The lipid damage was decreased by 40% in the liver, and 56% in the kidney of rats pretreated with curcumin. The association reduced lipid damage by 50% and 36%, and protein damage by 77% and 64% in the liver and kidney, respectively. Rutin better prevented the decrease in the antioxidant defenses, increasing SOD by 34%, CAT by 246% and GST by 84% in the liver, as well as SOD by 119% and GST by 190% in the kidney. Also, analyses of blood and spleen parameters of untreated and pretreated non-hyperlipidemic rats showed no signs of immunotoxicity. Despite showing protective effects, the association did not perform better than the isolated compounds. Here, we showed that rutin and/or curcumin reestablished the immune homeostasis and redox balance disrupted by hyperlipidemia in peripheral organs of rats.

Astrocaryum aculeatum fruit improves inflammation and redox balance in phytohemagglutinin-stimulated macrophages.

ETHNOPHARMACOLOGICAL RELEVANCE: The fruit of Astrocaryum aculeatum G.Mey. (tucumã) is highly consumed by riverside communities in the Amazonian region. These communities have recently been shown to have increased longevity and reduced prevalence of age-related morbidity. Tucumã, which is locally used in their diet and traditional medicine may contribute to these features. AIM OF THE STUDY: To investigate the anti-inflammatory and antioxidant properties of A. aculeatum extract against phytohemagglutinin-induced inflammation in cell cultures. MATERIALS AND METHODS: Cell viability and cytotoxicity assays, gene expression of interleukins IL-1ß, IL-6, IL-10, levels of reactive oxygen species (ROS), nitric oxide (NO) and thiols were employed, as well as the activities of antioxidant enzymes in RAW 264.7 cells stimulated with phytohemagglutinin to mimic inflammation. RESULTS: The extract of A. aculeatum fruit inhibited macrophage proliferation (P < 0.05), arrested the cell cycle in G0/G1 phase (P < 0.001), increased antioxidant defenses (P < 0.01), reduced oxidative stress (P < 0.01), and modulated genes related to the inflammatory response (P < 0.001). CONCLUSION: Our results demonstrate that A. aculeatum fruit has anti-inflammatory and antioxidant capacities. These beneficial effects of tucumã on cells are also likely to be seen in vivo, thereby suggesting that its extract is a suitable therapeutic adjuvant in the prevention or treatment of inflammatory diseases.

ATP and adenosine: Role in the immunopathogenesis of rheumatoid arthritis.

Rheumatoid arthritis (RA) is a classic inflammatory autoimmune disease. Local joint destruction and extra-articular manifestations of RA deeply compromise the life quality of the affected patients. RA immunopathogenesis depends on continuous immunogenic activation in which the purinergic system participates. The purinergic system comprises the signaling and metabolism of purines such as adenosine triphosphate (ATP) and adenosine. ATP signaling is involved in the activation and maintenance of the inflammatory state of RA through the activation of P2X7 and the production of cytokines, which orchestrate the pathogenesis of RA. The breakdown of ATP through the CD39/CD73 axis produces adenosine, which mostly inhibits the inflammatory process through activation of specific P1 receptors. Adenosine is hydrolyzed by adenosine deaminase (ADA) that interacts with other molecules playing additional roles in this disease. This review explores the release, metabolism, and the effects of binding of ATP and adenosine to their respective receptors in the context of RA, as well as their potential use as biomarkers and therapeutic targets.

Co-Nanoencapsulation of Vitamin D3 and Curcumin Regulates Inflammation and Purine Metabolism in a Model of Arthritis.

We analyzed the effects of a nanoencapsulated association of curcumin and vitamin D3 on purine metabolism enzymes in neutrophils, lymphocytes, and platelets in a model of adjuvant-induced arthritis (AIA) in rats. Following AIA induction, the animals were treated for 15 days with free and nanoencapsulated curcumin (4 mg/kg), nanocapsules of vitamin D3 (VD3) (15.84 IU/day), a nanoencapsulated combination of curcumin and VD3, vehicle, or blank nanocapsules. The animals were euthanized, and blood was collected to evaluate the activities of E-NTPDase, adenosine deaminase (ADA), and myeloperoxidase (MPO), as well as reactive oxygen species (ROS) levels and biochemical parameters. Also, the liver and kidney were collected for histological analysis. The changes in the activities of purinergic enzymes indicated that inflammation was significantly reverted by vitamin D3 and curcumin co-nanoencapsulation treatments in the arthritic rats. The reduction of inflammation was confirmed by the reduction in the signs and symptoms of AIA, as well as in MPO activity by all formulations. The treatments with nanocapsules reverted histological alterations in the kidney. Serum parameters were not altered by the induction or treatments. Our results suggest that co-nanoencapsulation of vitamin D3 and curcumin is an efficient alternative adjuvant treatment for rheumatoid arthritis as it reverts the changes in the purine metabolism and reduces arthritis-associated inflammation.

Rutin and curcumin reduce inflammation, triglyceride levels and ADA activity in serum and immune cells in a model of hyperlipidemia.

Hyperlipidemia is associated with endothelial dysfunction and inflammatory disorders. Adenosine and adenosine deaminase (ADA) modulate immune responses and lipid metabolism. Curcumin and rutin are polyphenols with antioxidant, anti-inflammatory, and hypolipidemic effects. We evaluated the action of rutin and curcumin in the lipid levels and inflammation, as well as their effect on ADA activity in serum, lymphocytes, platelets, and neutrophils of hyperlipidemic rats. Adult male Wistar rats pretreated with curcumin and/or rutin for 30 days were submitted to Poloxamer-407- induced hyperlipidemia. Biochemical, hematological, and oxidative stress parameters, as well as serum and extracellular ADA activity, were performed 36h post-induction. Hyperlipidemia was confirmed by the increase in total cholesterol (TC) and triglycerides (TG). Hematological alterations, elevated reactive oxygen species (ROS) levels, and increased myeloperoxidase (MPO) and ADA activities were observed in hyperlipidemic rats. Curcumin and the curcumin/rutin association decreased TG and increased high-density lipids (HDL) levels. The pretreatments prevented changes in the hematological parameters, decreased the activities of MPO in plasma and ADA in serum and cells. Cholesterol and ROS levels were not altered by the pretreatments. Our results show that pretreatments with rutin and/or curcumin prevent the hyperlipidemia-induced inflammation. Pretreatments with curcumin and/or rutin are potential complementary therapies in the prevention of hypertriglyceridemia and inflammation.

Activity and expression of E-NTPDase is altered in peripheral lymphocytes of systemic lupus erythematosus patients.

BACKGROUND: Systemic lupus erythematosus (SLE) is an inflammatory autoimmune disease, where there is irreversible breakdown of immunological self-tolerance. Extracellular adenosine triphosphate (ATP) and adenosine are signaling molecules that play an important part in the immune response. During inflammation and the immune response, a group of enzymes control these molecules, including ectonucleoside triphosphate diphosphohydrolase (E-NTPDase), E-5'-nucleotidase, and ecto-adenosine deaminase (E-ADA). We determined the activity and expression of E-NTPDase, the expression of E-5'-nucleotidase, the activity of E-ADA in lymphocytes and serum of SLE patients. METHODS: This study involved 35 patients with SLE and 30 healthy subjects as a control group. E-NTPDase activity and expression were increased in lymphocytes from SLE patients (31% and 37% for activity and expression, respectively) compared with the control group. RESULTS: An approximately 42% increase in E-ADA activity in lymphocytes was observed in SLE patients compared with the control group, in serum the ADA activity was decreased by 57% in SLE patients. Expression of E-5'-nucleotidase was not changed in SLE patients. CONCLUSIONS: E-NTPDase and E-ADA perform key functions in the modulation of the immune and inflammatory response in SLE.

Ecto-enzymes activities in splenic lymphocytes of mice experimentally infected by Trypanosoma cruzi and treated with specific avian immunoglobulins: an attempt to improve the immune response.

The aim of this study was to evaluate the therapeutic efficacy of specific avian polyclonal antibodies (IgY) against Trypanosoma cruzi and their interaction with ecto-enzymes of the purinergic system (NTPDase and adenosine deaminase (ADA) activities) in splenic lymphocytes. For this, mice were divided into six groups: three non-infected (A, B, and C) and three infected (D, E, and F). The groups A and D were composed by negative and positive controls, respectively; while the groups B and E were treated prophylactically with IgY (50 mg/kg), and the groups C and F were treated therapeutically with IgY (50 mg/kg). Treatment with IgY reduced parasitemia on day 6 post-infection (PI) compared to the infected control group, but it was similar on day 8 PI. Moreover, infected and treated animals (the groups E and F) did not show neither amastigotes in the cardiac tissue nor cardiac lesions when compared to the positive control group (the group D). The E-NTPDase (ATP and ADP as substrate) and ADA activities in splenic lymphocytes increased significantly in the positive control group (the group D) compared to the negative control group (the group A). The therapeutic treatment of IgY (the group F) was able to prevent the increase of E-NTPDase and E-ADA activities compared to the positive control group (the group D), but this finding was not observed in animals that received the prophylactic treatment (the group E). The therapeutic treatment of IgY may be considered an interesting approach to improve the immune response of mice experimentally infected by T. cruzi.

Pretreatment with quercetin prevents changes in lymphocytes E-NTPDase/E-ADA activities and cytokines secretion in hyperlipidemic rats.

Hyperlipidemia (HL) is a condition associated with endothelial dysfunction and inflammatory disorders. Purinergic system ectoenzymes play an important role in modulating the inflammatory and immune response. This study investigated whether the preventive treatment with quercetin is able to prevent changes caused by hyperlipidemia in the purinergic system, through the activities of E-NTPDase and E-ADA in lymphocytes, and quantify the nucleotides and nucleoside, and the secretion of anti- and proinflammatory cytokines. Animals were divided into saline/control, saline/quercetin 5 mg/kg, saline/quercetin 25 mg/kg, saline/quercetin 50 mg/kg, saline/simvastatin (0.04 mg/kg), hyperlipidemia, hyperlipidemia/quercetin 5 mg/kg, hyperlipidemia/quercetin 25 mg/kg, hyperlipidemia/quercetin 50 mg/kg, and hyperlipidemia/simvastatin. Animals were pretreated with quercetin for 30 days and hyperlipidemia was subsequently induced by intraperitoneal administration of 500 mg/kg of poloxamer-407. Simvastatin was administered after the induction of hyperlipidemia. Lymphocytes were isolated and E-NTPDase and E-ADA activities were determined. Serum was separated for the cytokines and nucleotide/nucleoside quantification. E-NTPDase and E-ADA activities were increased in lymphocytes from hyperlipidemic rats and pretreatment with quercetin was able to prevent the increase in the activities of these enzymes caused by hyperlipidemia. Hyperlipidemic rats when receiving pretreatment with quercetin and treatment with simvastatin showed decreased levels of ATP and ADP when compared to the untreated hyperlipidemic group. The IFN-γ and IL-4 cytokines were increased in the hyperlipidemic group when compared with control group, and decreased when hyperlipidemic rats received the pretreatment with quercetin. However, pretreatment with quercetin was able to prevent the alterations caused by hyperlipidemia probably by regulating the inflammatory process. We can suggest that the quercetin is a promising compound to be used as an adjuvant in the treatment of hyperlipidemia.

Changes in inflammatory/cardiac markers of HIV positive patients.

HIV replication promotes atherogenesis and participates in the immune response to the virus, thereby influencing the inflammatory profile. These changes may, in turn, contribute to the risk of cardiovascular diseases with involvement of platelets. However, adenine nucleotides and nucleosides involved in thromboregulation and modulation of immune response may therefore be affected by these alterations. OBJECTIVES: This study sought to evaluate the profile of pro and anti-inflammatory cytokines (IL-10, IL-6, IL-17, TNF, IL-4, IL-2 and IFN-gamma), cardiac markers (troponin, CK, CK MB, LDH, CRP) in HIV-positive patients and assess the in vitro effect of antiretroviral therapy on the activities of ectonucleotidases (E-NTPDase and E-5'-nucleotidase) in human platelets. DESIGN AND METHODS: Blood samples were obtained from ten HIV positive patients at the Infectious Disease Clinic of the University Hospital of Santa Maria, Brazil and ten HIV negative individuals (control group) for this study. RESULTS: The results revealed that there were significant (P < 0.05) increases in serum levels of IL-6 and IFN-gamma with no significant (P > 0.05) changes in the serum levels of the cardiac markers investigated (CK, CK-MB, troponin, LDH and CRP). In addition, the ectonucleotidases (E-NTPDase and E-5'-nucleotidase) activities were not altered (P > 0.05) in human platelets when incubated with different antiretroviral drugs in vitro. CONCLUSIONS: The results of this study suggest that, despite successful treatment, a proinflammatory state is not altered in HIV patients, and that antiretroviral therapy per se does not change the purinergic profile.

Treatment with 3'-deoxyadenosine and deoxycoformycin in mice infected by Trypanosoma cruzi and its side effect on purinergic enzymes.

The aim of this study was to evaluate the efficacy of 3'-deoxyadenosine and deoxycoformycin combination in the treatment of mice infected by T. cruzi, as well as to verify the influence of the treatment on purinergic enzymes. Heart and serum samples were collected from 60 mice (30 infected and 30 uninfected) at day 12 post-infection. To verify treatment efficacy, parasitemia was monitored, and the treatment with 3'-deoxy adenosine and deoxycoformycin combination was able to reduce it, but had no curative effect on mice. Seric activities of NTPDase (ATP and ADP substrate) and ADA were increased significantly in untreated mice infected by T. cruzi compared to the negative control, as well as mice treated with 3'-deoxyadenosine and deoxycoformycin (alone or combined) modulated the activity of NTPDase (ATP and ADP substrate), preventing them from increasing in infected animals (activity similar to healthy animals). Treatment with deoxycoformycin alone and associated with 3'-deoxyadenosine modulated the activity of ADA preventing them from increasing in infected animals. However, seric activities of ADA in mice treated with 3'-deoxyadenosine (cordycepin) alone does not modify the ADA activity compared with infected and non-treated mice. However, the 5'-nucleotidase activity decreased significantly in infected untreated animals and the same occurred in infected and treated animals with deoxycoformycin and 3'-deoxyadenosine. However, treatment with deoxycoformycin associated with 3'-deoxyadenosine preventing them from decreasing the 5'-nucleotidase activity. Therefore, we conclude that the treatments did not have curative success for mice infected by T. cruzi. However, the treatments were able to modulate the purinergic enzymes during the infection by T. cruzi, which may contribute to reduce the inflammatory damage in heart.

Sepsis induced by cecal ligation and perforation (CLP) alters nucleotidase activities in platelets of rats.

Sepsis is a potentially lethal condition, and it is associated with platelet alterations. The present study sought to investigate the activity of ecto-nucleoside triphosphate diphosphohydrolase (E-NTPDase), E-5'-nucleotidase, and ecto-adenosine deaminase (E-ADA) in the platelets of rats that were induced with sepsis. Male Wistar rats were divided into three groups of ten animals each: a negative control group (normal; NC); a group that underwent surgical procedures (sham); and a group that underwent cecal ligation and perforation (CLP). The induction of sepsis was confirmed by bacteremia, and the causative pathogen identified was Escherichia coli. Hematological parameters showed leukocytosis and thrombocytopenia in animals in the septic group. The results also revealed that there were significant (p < 0.05) increases in adenosine triphosphate (ATP) and adenosine monophosphate (AMP) hydrolyses, and in the deamination of adenosine in the CLP group compared to the sham and control groups. Conversely, ADP hydrolysis was significantly decreased (p < 0.05) in the CLP group compared to the sham and control groups. Purine levels were analyzed by high-performance liquid chromatography (HPLC) in serum samples from control, sham, and CLP groups. Increased concentrations of ATP, adenosine, and inosine were found in the CLP group compared to the sham and control groups. Conversely, the concentrations of ADP and AMP in the CPL group were not significantly altered. We suggest that alterations in hematological parameters, nucleotide hydrolysis in platelets, and nucleotide concentrations in serum samples of rats with induced sepsis may be related to thromboembolic events.

Treatment with tucumã oil (Astrocaryum vulgare) for diabetic mice prevents changes in seric enzymes of the purinergic system: Improvement of immune system.

The aim of this study was to evaluate the enzymatic activity of the purinergic system in sera samples from alloxan-induced diabetic mice treated with tucumã oil (Astrocaryum vulgare). For this, the mice were divided into four groups (n=6): control/water (the group CW); control/tucumã oil (the group CT); diabetic/water (the group DW), and diabetic/tucumã oil (the group DT) treated for 14days with 5.0mLkg-1 via oral gavage. On day 14 post-treatment, mice were submitted to euthanasia and blood samples were collected by cardiac puncture. Tucumã oil treatment significantly decreased (p<0.05) blood glucose levels in the group DT compared to the group DW. These results demonstrated an increase (p<0.05) in NTPDase (adenosine triphosphate (ATP substrate) or adenosine diphosphate (ADP substrate)), 5'-nucleotidase (AMP substrate) and adenosine deaminase (ADA; adenosine substrate) activities in serum from the group DW compared to the group CW. Tucumã oil treatment prevented these alterations in the group DT compared to the group DW, and restored these parameters near to the group CW. In summary, the treatment with tucumã oil was able to modulate the alterations caused by hyperglycemia probably by the presence of carotenoids compounds, maintaining normal levels of ATP, ADP, AMP and adenosine, molecules that could exhibit anti-inflammatory properties, depending on their concentration. Thus, the tucumã oil is a promising natural compound with protective action against diabetes and its side effects, such as changes in the purinergic system, improving the immune system.

Diphenyl diselenide modulates nucleotidases, reducing inflammatory responses in the liver of Toxoplasma gondii-infected mice.

The aim of this study was to verify the effect of diphenyl diselenide (PhSe)2 on hepatic nucleotidases and on the concentration of purines in mice infected by Toxoplasma gondii. The animals were divided into four groups: Group A (uninfected), Group B (uninfected and treated with (PhSe)2), Group C (infected), and Group D (infected and treated with (PhSe)2). The inoculation (groups C and D) was performed with 50 cysts of T. gondii (ME-49 strain). Mice from groups B and D were treated with 5 µmol kg-1 of (PhSe)2. Liver tissue from infected mice showed less severe inflammation, elevated ATP/ADO ratio, elevated NTPDase, 5'nucleotidase, and ADA activities compared to the uninfected group (Group A; P < 0.05). However, infected and treated mice showed decreased ATP levels and elevated ADO levels, as well as higher NTPDase and 5'nucleotidase activities and decreased ADA activity in the hepatic tissue compared to the infected group (P < 0.05). Moreover, the (PhSe)2 treatment of infected mice reduced the hepatic inflammation and showed an immunomodulatory effect on ectonucleotidases of hepatic lymphocytes, which it returned to basal levels. Therefore, chronic infection by T. gondii induces hepatic inflammation in mice, and it is possible that purine levels and nucleotidase activities in hepatic tissue are related to the pathogenesis of the infection in this tissue. The treatment with (PhSe)2 was able to reverse the hepatic inflammation in mice chronically infected, possibly due to the modulation of purinergic enzymes that produce an anti-inflammatory profile through the purinergic system in the liver tissue.

Toxoplasmosis treatment with diphenyl diselenide in infected mice modulates the activity of purinergic enzymes and reduces inflammation in spleen.

Toxoplasma gondii, an intracellular protozoan, may cause chronic infection in the brain tissue of the host inducing a systemic pro-inflammatory profile. Chronic infections can induce numerous physiological changes, such as alterations in the immune and oxidative profiles. Diphenyl diselenide (PhSe)2, an organoselenium compound, has shown antioxidant and immunomodulatory activities in recent studies. So, the aim of this study was to investigate the activity of purinergic enzymes and reactive oxygen species (ROS) in serum and spleen of mice chronically infected by T. gondii, untreated and treated with (PhSe)2. For this experiment, were divided into four groups: Group A (healthy mice), Group B (healthy mice treated with (PhSe)2), Group C (infected mice) and Group D (infected mice treated with (PhSe)2). Group C and group D were infected via oral route with ME49 Toxoplasma gondii strain. Groups B and D were treated subcutaneously with 5 µmol kg-1 of (PhSe)2. Chronic T. gondii infection induced splenomegaly and physiological changes in the spleen and raised histologic inflammatory markers, ROS levels and the activity of purinergic enzymes activity such as NTPDase, 5´nucleotidase and ADA. In serum, the infection increased 5´nucleotidase and ADA activities. (PhSe)2per se has managed to decrease ROS levels and ADA activity and increase NTPDase and 5´nucleotidase in spleen. In infected mice, treatment with (PhSe)2 reversed splenomegaly, reduced histological inflammatory markers, ROS levels and ADA activity in the spleen. Our results prove that chronic toxoplasmosis can induce splenomegaly, heightens ROS levels and purinergic enzyme activity in mice. These results suggest that (PhSe)2 is a potential therapy for the alterations found in the spleen in chronic T. gondii infection.

Melaleuca alternifolia essential oil prevents alterations to purinergic enzymes and ameliorates the innate immune response in silver catfish infected with Aeromonas hydrophila.

Aeromonas hydrophila infection represents a major impediment to the development of aquaculture, leading to important economic losses. Over the last few years, different methods have been used to counteract and minimize the negative effects of this infection, such as the use of Melaleuca alternifolia essential oil, popularly known as tea tree oil (TTO), that possess a bactericide action against A. hydrophila. The purinergic system develops an important role in the inflammatory response, principally due to involvement of adenosine triphosphate (ATP) in the inflammatory process, as well as by the anti-inflammatory properties of adenosine (Ado), a molecule that is controlled by NTPDase, 5'-nucleotidase and adenosine deaminase (ADA) enzymes. Thus, the aim of this study was to investigate the involvement of purinergic enzymes in the pathogenesis of A. hydrophila infection, and whether the purinergic pathway and innate immune response are involved in the protective effects of TTO in silver catfish (Rhamdia quelen) experimentally infected with A. hydrophila. Our results revealed that A. hydrophila infection increased seric NTPDase and 5'-nucleotidase activity, while ADA activity decreased. Also, the seric levels of pro-inflammatory cytokines such as interleukin-1 (IL-1), IL-6, tumor necrosis factor alpha (TNF-α) and interferon gamma (INF-γ) increased in the infected fish, while the seric level of anti-inflammatory interleukin-10 (IL-10) decreased. Treatment with TTO was able to prevent the impairment of purinergic enzymes and improve the innate immune response through the modulation of cytokine response during A. hydrophila infection. In summary, prophylactic therapy with TTO can be considered an important approach to improve the immune response and consequently avoid the inflammatory process in fish infected with A. hydrophila.