Sheltered in Stromal Tissue Cells, Trypanosoma cruzi Orchestrates Inflammatory Neovascularization via Activation of the Mast Cell Chymase Pathway.

Microangiopathy may worsen the clinical outcome of Chagas disease. Given the obstacles to investigating the dynamics of inflammation and angiogenesis in heart tissues parasitized by Trypanosoma cruzi, here we used intravital microscopy (IVM) to investigate microcirculatory alterations in the hamster cheek pouch (HCP) infected by green fluorescent protein-expressing T. cruzi (GFP-T. cruzi). IVM performed 3 days post-infection (3 dpi) consistently showed increased baseline levels of plasma extravasation. Illustrating the reciprocal benefits that microvascular leakage brings to the host-parasite relationship, these findings suggest that intracellular amastigotes, acting from inside out, stimulate angiogenesis while enhancing the delivery of plasma-borne nutrients and prosurvival factors to the infection foci. Using a computer-based analysis of images (3 dpi), we found that proangiogenic indexes were positively correlated with transcriptional levels of proinflammatory cytokines (pro-IL1ß and IFN-γ). Intracellular GFP-parasites were targeted by delaying for 24 h the oral administration of the trypanocidal drug benznidazole. A classification algorithm showed that benznidazole (>24 h) blunted angiogenesis (7 dpi) in the HCP. Unbiased proteomics (3 dpi) combined to pharmacological targeting of chymase with two inhibitors (chymostatin and TY-51469) linked T. cruzi-induced neovascularization (7 dpi) to the proangiogenic activity of chymase, a serine protease stored in secretory granules from mast cells.

Chymase inhibition: A key factor in the anti-inflammatory activity of ethanolic extracts and spilanthol isolated from Acmella oleracea.

ETHNOPHARMACOLOGICAL RELEVANCE: Acmella oleracea (L.) R. K. Jansen (Asteraceae), known as jambú in Brazil, is used in traditional medicine as analgesic and for inflammatory conditions, characterized by the presence of N-alkylamides, mainly spilanthol. This bioactive compound is responsible for the above-described pharmacological properties, including sialagogue and anesthetic. AIM OF THE STUDY: This study aimed to characterize the anti-inflammatory effects of A. oleracea leaves (AOEE-L) and flowers (AOEE-F) extracts, including an isolated alkylamide (spilanthol), using in vitro and in vivo models. The mechanism underlying this effect was also investigated. MATERIALS AND METHODS: Extracts were analyzed by HPLC-ESI-MS/MS in order to characterize the N-alkylamides content. AOEE-L, AOEE-F (25-100 µg/mL) and spilanthol (50-200 µM) were tested in vitro on VSMC after stimulation with hyperglycemic medium (25 mM glucose). Their effects over nitric oxide (NO) generation, chymase inhibition and expression, catalase (CAT), superoxide anion (SOD) radical activity were evaluated. After an acute administration of extracts (10-100 mg/mL) and spilanthol (6.2 mg/mL), the anti-inflammatory effects were evaluated by applying the formalin test in rats. Blood was collected to measure serum aminotransferases activities, NO activity, creatinine and urea. RESULTS: A number of distinct N-alkylamides were detected and quantified in AOEE-L and AOEE-F. Spilanthol was identified in both extracts and selected for experimental tests. Hyperglycemic stimulation in VSMC promoted the expression of inflammatory parameters, including chymase, NO, CAT and SOD activity and chymase expression, all of them attenuated by the presence of the extracts and spilanthol. The administration of extracts or spilanthol significantly inhibited edema formation, NO production and cell tissue infiltration in the formalin test, without causing kidney and liver toxicity. CONCLUSION: Taken together, these results provide evidence for the anti-inflammatory activity of leaves and flowers extracts of jambú associated distinctly with their chemical profile. The effects appear to be associated with the inhibition of chymase activity, suppression of the proinflammatory cytokine NO and antioxidant activities.

Mast cell heterogeneity and anti-inflammatory annexin A1 expression in leprosy skin lesions.

Mast cells (MCs) have important immunoregulatory roles in skin inflammation. Annexin A1 (ANXA1) is an endogenous anti-inflammatory protein that can be expressed by mast cells, neutrophils, eosinophils, monocytes, epithelial and T cells. This study investigated MCs heterogeneity and ANXA1 expression in human dermatoses with special emphasis in leprosy. Sixty one skin biopsies from 2 groups were investigated: 40 newly diagnosed untreated leprosy patients (18 reaction-free, 11 type 1 reaction/T1R, 11 type 2 reaction/T2R); 21 patients with other dermatoses. Tryptase/try+ and chymase/chy + phenotypic markers and toluidine blue stained intact/degranulated MC counts/mm2 were evaluated. Try+/chy+ MCs and ANXA1 were identified by streptavidin-biotin-peroxidase immunostaining and density was reported. In leprosy, degranulated MCs outnumbered intact ones regardless of the leprosy form (from tuberculoid/TT to lepromatous/LL), leprosy reactions (reactional/reaction-free) and type of reaction (T1R/T2R). Compared to other dermatoses, leprosy skin lesions showed lower numbers of degranulated and intact MCs. Try+ MCs outnumbered chy+ in leprosy lesions (reaction-free/reactional, particularly in T2R), but not in other dermatoses. Compared to other dermatoses, ANXA1 expression, which is also expressed in mast cells, was higher in the epidermis of leprosy skin lesions, independently of reactional episode. In leprosy, higher MC degranulation and differential expression of try+/chy+ subsets independent of leprosy type and reaction suggest that the Mycobacterium leprae infection itself dictates the inflammatory MCs activation in skin lesions. Higher expression of ANXA1 in leprosy suggests its potential anti-inflammatory role to maintain homeostasis preventing tissue and nerve damage.

Mast cell-nerve interaction in the colon of Trypanosoma cruzi-infected individuals with chagasic megacolon.

Chagas disease is an infection caused by the parasite Trypanosoma cruzi that affects millions of people worldwide and is endemic in Latin America. Megacolon is the most frequent complication of the digestive chronic form and happens due to lesions of the enteric nervous system. The neuronal lesions seem to initiate in the acute phase and persist during the chronic phase, albeit the mechanisms involved in this process are still debated. Among the cells of the immune system possibly involved in this pathological process is the mast cell (MC) due to its well-known role in the bi-directional communication between the immune and nervous systems. Using ultrastructural analysis, we found an increased number of degranulated MCs in close proximity to nerve fibers in infected patients when compared with uninfected controls. We also immunostained MCs for the two pro-inflammatory molecules tryptase and chymase, the first being also important in neuronal death. The number of MCs immunostained for tryptase or chymase was increased in patients with megacolon, whereas increased tryptase staining was additionally observed in patients without megacolon. Moreover, we detected the expression of the tryptase receptor PAR2 in neurons of the enteric nervous system, which correlated to the tryptase staining results. Altogether, the data presented herein point to the participation of MCs on the denervation process that occurs in the development of T. cruzi-induced megacolon.

Blunting of cardioprotective actions of estrogen in female rodent heart linked to altered expression of cardiac tissue chymase and ACE2.

BACKGROUND: Diastolic dysfunction develops in response to hypertension and estrogen (E2) loss and is a forerunner to heart failure (HF) in women. The cardiac renin-angiotensin system (RAS) contributes to diastolic dysfunction, but its role with respect to E2 and blood pressure remain unclear. METHODS: We compared the effects of ovariectomy (OVX) or sham surgery on the cardiac RAS, left ventricular (LV) structure/function, and systemic/intracardiac pressures of spontaneously hypertensive rats (SHRs: n = 6 intact and 6 OVX) and age-matched Wistar-Kyoto (WKY: n = 5 intact and 4 OVX) controls. RESULTS: WKY rats were more sensitive to OVX than SHRs with respect to worsening of diastolic function, as reflected by increases in Doppler-derived filling pressures (E/e') and reductions in myocardial relaxation (e'). This pathobiologic response in WKY rats was directly linked to increases in cardiac gene expression and enzymatic activity of chymase and modest reductions in ACE2 activity. No overt changes in cardiac RAS genes or activities were observed in SHRs, but diastolic function was inversely related to ACE2 activity. CONCLUSION: Endogenous estrogens exert a more significant regulatory role upon biochemical components of the cardiac RAS of WKY versus SHRs, modulating the lusitropic and structural components of its normotensive phenotype.

Novedades en el sistema renina-angiotensina / News in the renin-angiotensin system / Novidades no sistema renina-angiotensina

La insuficiencia cardíaca (IC) se define como la incapacidad del corazón de satisfacer los requerimientos metabólicos de los tejidos en reposo o durante el ejercicio ligero. Esta incapacidad motiva una respuesta neurohormonal que se interrelaciona con las alteraciones hemodinámicas vinculadas a las cargas ventriculares, más los problemas funcionales y estructurales del miocardio que puedan existir. En la fisiopatología cardiovascular (de la IC, de la hipertensión arterial, de las valvulopatías, de la enfermedad coronaria, etc.), tiene participación clave el sistema renina angiotensina (SRA), cuyas acciones principales incluyen la regulación de la presión arterial, el tono vascular, la volemia y facilitar la transmisión simpática. El SRA participa en la remodelación ventricular del infartado y del hipertenso, así como en la remodelación vascular. Esta revisión sobre algunos nuevos aspectos del SRA, publicados recientemente en la literatura médica, se acompaña de un resumen de los conceptos clásicos, para ver cómo los nuevos se instalan en ellos, se abren nuevos caminos en la investigación fisiológica y farmacológica, al ampliarse significativamente el espectro de acción del SRA, eje de la fisiopatología de la hipertensión arterial, de la insuficiencia cardíaca y de otras patologías.

Heart failure (HF) is defined as the inability of the heart to satisfy the metabolic requirements of the tissues at rest or during light exercise. This failure motivates neurohormonal response that interrelates with the hemodynamic changes related to ventricular loads more functional and myocardial structural problems that may exist. In cardiovascular pathophysiology (HF, arterial hypertension, valvular heart disease, coronary disease, etc.) has key role the renin angiotensin system (RAS), whose main activities include to regulate blood pressure, vascular tone, volemia and to facilitate sympathetic transmission. The RAS participates in ventricular remodeling of the infarcted and of the hypertensive as well as vascular remodeling. This review of some new aspects of the RAS, recently published in the medical literature, is accompanied by a summary of the classical concepts, to see how new they are installed, opening new pathways in physiological and pharmacological research, to significantly expand the RAS spectrum of action, axis of the pathophysiology of hypertension, heart failure and other diseases.

A insuficiência cardíaca (IC) é definida como a incapacidade do coração para atender às necessidades metabólicas dos tecidos em repouso ou durante exercícios leves. Esta falha motiva resposta neuro-hormonal que interage com as alterações hemodinâmicas relacionadas às cargas ventriculares mais os problemas funcionais e estruturais do miocárdio que possam existir. Na fisiopatologia cardiovascular (IC, hipertensão arterial, doença cardíaca valvular, doença coronariana, etc.) tem papel fundamental no sistema renina angiotensina (SRA), cujas ações principais incluem a regulação da pressão arterial, do tônus vascular, da volemia e facilitar a transmissão simpática. O SRA participa de remodelação ventricular do infartado e do hipertenso assim como a remodelação vascular. Esta revisão de alguns novos aspectos da SRA, recentemente publicado na literatura médica, é acompanhada por um resumo dos conceitos clássicos, para ver como novo eles estão instalados, abrindo novos caminhos na pesquisa fisiológica e farmacológica, para expandir de forma significativa a espectro de ação da SRA, eixo da fisiopatologia da hipertensão, insuficiência cardíaca e outras doenças.

Novedades en el sistema renina-angiotensina / News in the renin-angiotensin system / Novidades no sistema renina-angiotensina

La insuficiencia cardíaca (IC) se define como la incapacidad del corazón de satisfacer los requerimientos metabólicos de los tejidos en reposo o durante el ejercicio ligero. Esta incapacidad motiva una respuesta neurohormonal que se interrelaciona con las alteraciones hemodinámicas vinculadas a las cargas ventriculares, más los problemas funcionales y estructurales del miocardio que puedan existir. En la fisiopatología cardiovascular (de la IC, de la hipertensión arterial, de las valvulopatías, de la enfermedad coronaria, etc.), tiene participación clave el sistema renina angiotensina (SRA), cuyas acciones principales incluyen la regulación de la presión arterial, el tono vascular, la volemia y facilitar la transmisión simpática. El SRA participa en la remodelación ventricular del infartado y del hipertenso, así como en la remodelación vascular. Esta revisión sobre algunos nuevos aspectos del SRA, publicados recientemente en la literatura médica, se acompaña de un resumen de los conceptos clásicos, para ver cómo los nuevos se instalan en ellos, se abren nuevos caminos en la investigación fisiológica y farmacológica, al ampliarse significativamente el espectro de acción del SRA, eje de la fisiopatología de la hipertensión arterial, de la insuficiencia cardíaca y de otras patologías.(AU)

Heart failure (HF) is defined as the inability of the heart to satisfy the metabolic requirements of the tissues at rest or during light exercise. This failure motivates neurohormonal response that interrelates with the hemodynamic changes related to ventricular loads more functional and myocardial structural problems that may exist. In cardiovascular pathophysiology (HF, arterial hypertension, valvular heart disease, coronary disease, etc.) has key role the renin angiotensin system (RAS), whose main activities include to regulate blood pressure, vascular tone, volemia and to facilitate sympathetic transmission. The RAS participates in ventricular remodeling of the infarcted and of the hypertensive as well as vascular remodeling. This review of some new aspects of the RAS, recently published in the medical literature, is accompanied by a summary of the classical concepts, to see how new they are installed, opening new pathways in physiological and pharmacological research, to significantly expand the RAS spectrum of action, axis of the pathophysiology of hypertension, heart failure and other diseases.(AU)

A insuficiÛncia cardíaca (IC) é definida como a incapacidade do coraþÒo para atender Os necessidades metabólicas dos tecidos em repouso ou durante exercícios leves. Esta falha motiva resposta neuro-hormonal que interage com as alteraþ§es hemodinÔmicas relacionadas Os cargas ventriculares mais os problemas funcionais e estruturais do miocárdio que possam existir. Na fisiopatologia cardiovascular (IC, hipertensÒo arterial, doenþa cardíaca valvular, doenþa coronariana, etc.) tem papel fundamental no sistema renina angiotensina (SRA), cujas aþ§es principais incluem a regulaþÒo da pressÒo arterial, do t¶nus vascular, da volemia e facilitar a transmissÒo simpática. O SRA participa de remodelaþÒo ventricular do infartado e do hipertenso assim como a remodelaþÒo vascular. Esta revisÒo de alguns novos aspectos da SRA, recentemente publicado na literatura médica, é acompanhada por um resumo dos conceitos clássicos, para ver como novo eles estÒo instalados, abrindo novos caminhos na pesquisa fisiológica e farmacológica, para expandir de forma significativa a espectro de aþÒo da SRA, eixo da fisiopatologia da hipertensÒo, insuficiÛncia cardíaca e outras doenþas.(AU)