Effect of angiotensin II and angiotensin-(1-7) on proliferation of stem cells from human dental apical papilla.

The effects of the renin-angiotensin system (RAS) on stem cells isolated from human dental apical papilla (SCAPs) are completely unknown. Therefore, the aim of this study was to identify RAS components expressed in SCAPs and the effects of angiotensin (Ang) II and Ang-(1-7) on cell proliferation. SCAPs were collected from third molar teeth of adolescents and maintained in cell culture. Messenger RNA expression and protein levels of angiotensin-converting enzyme (ACE), ACE2, and Mas, Ang II type I (AT1) and type II (AT2) receptors were detected in SCAPs. Treatment with either Ang II or Ang-(1-7) increased the proliferation of SCAPs. These effects were inhibited by PD123319, an AT2 antagonist. While Ang II augmented mTOR phosphorylation, Ang-(1-7) induced ERK1/2 phosphorylation. In conclusion, SCAPs produce the main RAS components and both Ang II and Ang-(1-7) treatments induced cell proliferation mediated by AT2 activation through different intracellular mechanisms.

Subclinical failures of direct pulp capping of human teeth by using a dentin bonding system.

INTRODUCTION: The goal of this study was to examine the adhesive interface of pulp tissue to investigate subclinical failures after direct pulp capping (DPC) of human teeth by using a dentin adhesive system. METHODS: The pulps of 12 caries-free first premolars scheduled for extraction for orthodontic reasons were exposed and capped with the Single Bond adhesive system. The adhesive technique was carefully performed to ensure complete coverage of the exposed area and a satisfactory clinical aspect. After 1 (n = 6) and 30 days (n = 6), the teeth were extracted for evaluation of the adhesive interface under light microscopy and scanning electron microscopy. Brown-Brenn staining was used to detect bacteria. RESULTS: The clinical aspect of direct pulp capping during the operation was satisfactory, and all patients were asymptomatic in the postoperative phase. Brown-Brenn staining revealed no bacterial microleakage at both time points. A hybrid layer was seen on all walls but decreased gradually toward the area of pulp exposure. In contrast to clinical data, light microscopy and scanning electron microscopy revealed important subclinical bond failures near the area of exposed pulp. Some frequent findings were gaps between the restoration and the dentin substrate; unpolymerized monomers under the adhesive layer; interface breaks with blood extravasation between the layers of the adhesive system; rupture of the odontoblast layer; and multinucleated giant cells close to the bonding agent. CONCLUSIONS: The Single Bond adhesive system should not be used for direct pulp capping of human teeth because subclinical adhesive failures invariably occur at its interface with the pulp tissue.

Angiotensin-(1-7) receptor Mas is an essential modulator of extracellular matrix protein expression in the heart.

In this study we investigated the effects of genetic deletion of the Angiotensin-(1-7) receptor Mas or the Angiotensin II receptor AT(2) on the expression of specific extracellular matrix (ECM) proteins in atria, right ventricles and atrioventricular (AV) valves of neonatal and adult mice. Quantification of collagen types I, III and VI and fibronectin was performed using immunofluorescence-labeling and confocal microscopy. Picrosirius red staining was used for the histological assessment of the overall collagen distribution pattern. ECM proteins, metalloproteinases (MMP), ERK1/2 and p38 levels were quantified by western blot analysis. Gelatin zymography was used to evaluate the activity of MMP-2 and MMP-9. We observed that the relative levels of collagen types I and III and fibronectin are significantly higher in both the right ventricle and AV valves of neonatal Mas(-/-) mouse hearts (e.g., collagen type I: 85.28±6.66 vs 43.50±4.41 arbitrary units in the right ventricles of Mas(+/+) mice). Conversely, the level of collagen type VI was lower in the right ventricle and AV valves of Mas(-/-) mice. Adult Mas(-/-) mouse hearts presented similar patterns as observed in neonates. No significant differences in ECM protein level were detected in atria. Likewise, no changes in ECM levels were observed in AT(2) knockout mouse hearts. Although deletion of Mas induced a significant reduction in the level of the active form of MMP-2 in neonate hearts and a reduction of both MMP-2 and MMP-9 in adult Mas(-/-) mice, no significant differences were observed in MMP enzymatic activities when compared to controls. The levels of the active, phosphorylated forms of ERK1/2 and p38 were higher in hearts of both neonatal and adult Mas(-/-) mice. These observations suggest that Mas is involved in the selective expression of specific ECM proteins within both the ventricular myocardium and AV valves. The changes in the ECM profile may alter the connective tissue framework and contribute to the decreased cardiac performance observed in Mas(-/-) mice.

Potencial do MTA e sealapex agregado ao MTA no selamento apical / Potential of the MTA and sealapex added to the MTA in the apical sealing

Objetivo: O objetivo deste trabalho foi avaliar a capacidade de selamento apical do MTA- Angelus® e a combinação do Sealapex agregado ao pó do MTA- Ângelus® em retrobturações. Metodologia: Os canais de incisivos centrais de humanos foram instrumentados e em seguida obturados pela técnica da condensação lateral usando o cimento endodôntico Sealer 26. Os dentes foram divididos aleatoriamente em 2 grupos experimentais (n= 40) e dois controles (n= 4). Em seguida foram realizados apicectomia das raízes a 3 mm do ápice e preparo da cavidade com pontas lisas de ultrassom com 3 mm de profundidade, seguindo-se a obturação retrógrada da seguinte maneira: grupo 1, as retrocavidades foram preenchidas com MTA-Angelus® e o grupo 2, as retrocavidades foram preenchidas com Sealapex agregado ao pó do MTA- Angelus®. Depois de serem corados com solução de azul de metileno 1% por 24 horas, lavados por 24 horas, os dentes foram seccionados longitudinalmente no sentido vestíbulo-palatino, com um disco diamantado em duas metades, e analisados com uma lupa esteroscópica. Resultados: Os resultados obtidos foram submetidos à análise estatística e mostraram que, o grupo 2 apresentou menor infiltração que o grupo 1 (p<0,01). Conclusão: Concluiu-se então, que o pó MTA agregado ao Sealapex apresenta potencial para serem usados como materiais retrobturadores.

The purpose of this study was to examine the ability of sealing the root end cavities filled with MTA- Angelus® or Sealapex increased a powder MTA- Angelus®. Forty single-rooted extracted human teeth were cleaned, shaped and filled by the lateral condensation technique using Sealer 26. The specimens were divided randomly into two groups of 20. Folowing root-end resection and cavity preparation with ultrassonic, the root-end cavities were filled with: Group 1: MTA- Angelus® and group 2: Sealapex plus power MTA- Angelus®. The teeth were then submerged in solution methilene blue 1% dye for 24 hours, washed for 24 hours, and using a slow-speed diamond saw, the teeth were longitudinally sectioned into two halves and the quantitative analysis of leakage was performed using light microscopy. The results showed that the specimens of group 2 had significantley less leakage than group 1 (p< 0,01). The results of this study indicated that Sealapex plus power MTA presents the potential to be used as a root end filling material.

Indirect effects of oral tolerance improve wound healing in skin.

Tissue injury in adult mammalian skin frequently results in scarring while fetal mammalian skin heals with complete regeneration. Inflammatory reactions are among the factors thought to impair regeneration. Previous studies have shown that the injection of an immunologically tolerated protein blocks immune responses to unrelated antigens and is also able to inhibit inflammation in mice. This phenomenon, which we refer to as the indirect effects of oral tolerance, does not require the simultaneous injection of the tolerated antigen and the second antigen, and also occurs when the two antigens are given by separate routes of immunization. Herein, we investigated whether the i.p. injection of an orally tolerated antigen (ovalbumin, OVA) would inhibit inflammatory reactions at an incisional lesion and influence healing of adult mouse skin. In OVA-tolerant mice, the injection of OVA minutes before wounding altered inflammation: it reduced the numbers of mast cells, neutrophils, and lymphocytes but increased the number of macrophages around the lesion area. Tolerant mice also showed fewer myofibroblasts and reduced scar area. Furthermore, tolerant mice displayed a pattern of extracellular matrix deposition similar to that observed in intact skin, plus characteristics of regeneration, such as an increased deposition of fibronectin and tenascin-C. These observations suggest that the indirect effects of oral tolerance can alter the process of wound healing in skin and reduce scar formation.

Mesenchymal stem cells in the dental tissues: perspectives for tissue regeneration.

In recent years, stem cell research has grown exponentially owing to the recognition that stem cell-based therapies have the potential to improve the life of patients with conditions that range from Alzheimer's disease to cardiac ischemia and regenerative medicine, like bone or tooth loss. Based on their ability to rescue and/or repair injured tissue and partially restore organ function, multiple types of stem/progenitor cells have been speculated. Growing evidence demonstrates that stem cells are primarily found in niches and that certain tissues contain more stem cells than others. Among these tissues, the dental tissues are considered a rich source of mesenchymal stem cells that are suitable for tissue engineering applications. It is known that these stem cells have the potential to differentiate into several cell types, including odontoblasts, neural progenitors, osteoblasts, chondrocytes, and adipocytes. In dentistry, stem cell biology and tissue engineering are of great interest since may provide an innovative for generation of clinical material and/or tissue regeneration. Mesenchymal stem cells were demonstrated in dental tissues, including dental pulp, periodontal ligament, dental papilla, and dental follicle. These stem cells can be isolated and grown under defined tissue culture conditions, and are potential cells for use in tissue engineering, including, dental tissue, nerves and bone regeneration. More recently, another source of stem cell has been successfully generated from human somatic cells into a pluripotent stage, the induced pluripotent stem cells (iPS cells), allowing creation of patient- and disease-specific stem cells. Collectively, the multipotency, high proliferation rates, and accessibility make the dental stem cell an attractive source of mesenchymal stem cells for tissue regeneration. This review describes new findings in the field of dental stem cell research and on their potential use in the tissue regeneration.

Mesenchymal stem cells in the dental tissues: perspectives for tissue regeneration

In recent years, stem cell research has grown exponentially owing to the recognition that stem cell-based therapies have the potential to improve the life of patients with conditions that range from Alzheimer’s disease to cardiac ischemia and regenerative medicine, like bone or tooth loss. Based on their ability to rescue and/or repair injured tissue and partially restore organ function, multiple types of stem/progenitor cells have been speculated. Growing evidence demonstrates that stem cells are primarily found in niches and that certain tissues contain more stem cells than others. Among these tissues, the dental tissues are considered a rich source of mesenchymal stem cells that are suitable for tissue engineering applications. It is known that these stem cells have the potential to differentiate into several cell types, including odontoblasts, neural progenitors, osteoblasts, chondrocytes, and adipocytes. In dentistry, stem cell biology and tissue engineering are of great interest since may provide an innovative for generation of clinical material and/or tissue regeneration. Mesenchymal stem cells were demonstrated in dental tissues, including dental pulp, periodontal ligament, dental papilla, and dental follicle. These stem cells can be isolated and grown under defined tissue culture conditions, and are potential cells for use in tissue engineering, including, dental tissue, nerves and bone regeneration. More recently, another source of stem cell has been successfully generated from human somatic cells into a pluripotent stage, the induced pluripotent stem cells (iPS cells), allowing creation of patient- and disease-specific stem cells. Collectively, the multipotency, high proliferation rates, and accessibility make the dental stem cell an attractive source of mesenchymal stem cells for tissue regeneration. This review describes new findings in the field of dental stem cell research and on their potential use in the tissue regeneration.

Nos últimos anos, as pesquisas com células tronco têm aumentado exponencialmente devido ao reconhecimento de que seu potencial terapêutico pode melhorar a qualidade de vida de pacientes com diversas doenças, como a doença de Alzheimer, isquemias cardíacas e, até mesmo, nas pesquisas de medicina regenerativa que visa uma possível substituição de órgão perdidos, como por exemplo, os dentes. Baseado em habilidades de reparar tecidos injuriados e restaurar parcialmente as funções de um órgão, diversos tipos de células-tronco têm sido estudadas. Recentes evidências demonstram que as células-tronco são primariamente encontradas em nichos e que certos tecidos apresentam mais células-tronco que outros. Entre estes, os tecidos dentais são considerados como uma fonte rica de células-tronco mesenquimais adequado para aplicações em engenharia tecidual. Sabe-se que estas células têm o potencial de diferenciarem-se em diversos tipos celulares, incluindo osteoblastos, células progenitoras de neurônios, osteoblastos, condrócitos e adipósitos. Na odontologia, a biologia celular e a engenharia tecidual são de grande interesse, pois fornecem inovações na geração de novos materiais clínicos e ou na regeneração tecidual. Estas podem ser isoladas e crescidas em diversos meios de cultura apresentando grande potencial para ser usada na engenharia tecidual, incluindo regeneração de tecidos dentais, nervos e ossos. Recentemente, outra fonte de células tronco tem sido geradas a partir de células somáticas de humanos a um estágio de pluripotência, chamados de células-tronco pluripotente induzida (iPS) levando à criação de células-tronco específicas. Coletivamente, a multipotencialidade, altas taxas de proliferação e acessibilidade, faz das células-tronco dentárias uma fonte atrativa de células-tronco mesenquimais para regeneração tecidual. Esta revisão descreve novos achados no campo da pesquisa com células-tronco dentais e seu potencial uso na regeneração tecidual.

Attenuation of isoproterenol-induced cardiac fibrosis in transgenic rats harboring an angiotensin-(1-7)-producing fusion protein in the heart.

OBJECTIVE: It has been shown that Ang-(1-7) has cardioprotective actions. To directly investigate the effects of Ang-(1-7) specifically in the heart, we generated and characterized transgenic (TG) rats which express an Ang-(1-7)-producing fusion protein driven by the alpha-MHC promoter. METHODS AND RESULTS: After microinjection of the transgene into fertilized rat zygotes, we obtained four different transgenic lines. Homozygous animals were analyzed with regard to the expression profile of the transgene by ribonuclease protection assay. Transgene expression was detected mainly in the heart with weak or no expression in other organs. Heterozygous TG(hA-1-7)L7301 rats presented a significant increase in cardiac Ang-(1-7) concentration compared with control rats (17.1+/-2.1 versus 3.9+/-1.4 pg/mg protein in SD rats). Radiotelemetry analysis revealed that TG rats presented no significant changes in blood pressure and heart rate compared with normal rats. Overexpression of Ang-(1-7) in the heart produced slight improvement in resting cardiac function (+ dT/dt: 81530+/-1305.0 versus 77470+/-345.5 g/s bpm in SD rats, p < 0.05), which was in keeping with the enhanced [Ca(2+)] handling observed in cardiomyocytes of TG rats. TG(hA-1-7)L7301 rats also showed a greater capacity to withstand stress since TG rats showed a less pronounced deposition of collagen type III and fibronectin induced by isoproterenol treatment in the subendocardial area than in corresponding controls. In addition, hearts from TG rats showed reduced incidence and duration of reperfusion arrhythmias in comparison with SD rats. CONCLUSION: These results indicate that Ang-(1-7) has blood pressure-independent, antifibrotic effects, acting directly in the heart.

Molecular characterization of the Schistosoma mansoni zinc finger protein SmZF1 as a transcription factor.

BACKGROUND: During its development, the parasite Schistosoma mansoni is exposed to different environments and undergoes many morphological and physiological transformations as a result of profound changes in gene expression. Characterization of proteins involved in the regulation of these processes is of importance for the understanding of schistosome biology. Proteins containing zinc finger motifs usually participate in regulatory processes and are considered the major class of transcription factors in eukaryotes. It has already been shown, by EMSA (Eletrophoretic Mobility Shift Assay), that SmZF1, a S. mansoni zinc finger (ZF) protein, specifically binds both DNA and RNA oligonucleotides. This suggests that this protein might act as a transcription factor in the parasite. METHODOLOGY/PRINCIPAL FINDINGS: In this study we extended the characterization of SmZF1 by determining its subcellular localization and by verifying its ability to regulate gene transcription. We performed immunohistochemistry assays using adult male and female worms, cercariae and schistosomula to analyze the distribution pattern of SmZF1 and verified that the protein is mainly detected in the cells nuclei of all tested life cycle stages except for adult female worms. Also, SmZF1 was heterologously expressed in mammalian COS-7 cells to produce the recombinant protein YFP-SmZF1, which was mainly detected in the nucleus of the cells by confocal microscopy and Western blot assays. To evaluate the ability of this protein to regulate gene transcription, cells expressing YFP-SmZF1 were tested in a luciferase reporter system. In this system, the luciferase gene is downstream of a minimal promoter, upstream of which a DNA region containing four copies of the SmZF1 putative best binding site (D1-3DNA) was inserted. SmZF1 increased the reporter gene transcription by two fold (p

Novel pathogenic mutations and skin biopsy analysis in Knobloch syndrome.

PURPOSE: To facilitate future diagnosis of Knobloch syndrome (KS) and better understand its etiology, we sought to identify not yet described COL18A1 mutations in KS patients. In addition, we tested whether mutations in this gene lead to absence of the COL18A1 gene product and attempted to better characterize the functional effect of a previously reported missense mutation. METHODS: Direct sequencing of COL18A1 exons was performed in KS patients from four unrelated pedigrees. We used immunofluorescent histochemistry in skin biopsies to evaluate the presence of type XVIII collagen in four KS patients carrying two already described mutations: c.3277C>T, a nonsense mutation, and c.3601G>A, a missense mutation. Furthermore, we determined the binding properties of the mutated endostatin domain p.A1381T (c.3601G>A) to extracellular matrix proteins using ELISA and surface plasmon resonance assays. RESULTS: We identified four novel mutations in COL18A1, including a large deletion involving exon 41. Skin biopsies from KS patients revealed lack of type XVIII collagen in epithelial basement membranes and blood vessels. We also found a reduced affinity of p.A1381T endostatin to some extracellular matrix components. CONCLUSIONS: COL18A1 mutations involved in Knobloch syndrome have a distribution bias toward the coding exons of the C-terminal end. Large deletions must also be considered when point mutations are not identified in patients with characteristic KS phenotype. We report, for the first time, lack of type XVIII collagen in KS patients by immunofluorescent histochemistry in skin biopsy samples. As a final point, we suggest the employment of this technique as a preliminary and complementary test for diagnosis of KS in cases when mutation screening either does not detect mutations or reveals mutations of uncertain effect, such as the p.A1381T change.

Genetic deletion of the angiotensin-(1-7) receptor Mas leads to glomerular hyperfiltration and microalbuminuria.

Angiotensin-(1-7), an active fragment of both angiotensins I and II, generally opposes the vascular and proliferative actions of angiotensin II. Here we evaluated effects of the angiotensin-(1-7) receptor Mas on renal physiology and morphology using Mas-knockout mice. Compared to the wild-type animals, Mas knockout mice had significant reductions in urine volume and fractional sodium excretion without any significant change in free-water clearance. A significantly higher inulin clearance and microalbuminuria concomitant with a reduced renal blood flow suggest that glomerular hyperfiltration occurs in the knockout mice. Histological analysis found reduced glomerular tuft diameter and increased expression of collagen IV and fibronectin in the both the mesangium and interstitium, along with increased collagen III in the interstitium. These fibrogenic changes and the renal dysfunction of the knockout mice were associated with an upregulation of angiotensin II AT1 receptor and transforming growth factor-beta mRNA. Our study suggests that Mas acts as a critical regulator of renal fibrogenesis by controlling effects transduced through angiotensin II AT1 receptors in the kidney.

Angiotensin-(1-7) activates a tyrosine phosphatase and inhibits glucose-induced signalling in proximal tubular cells.

BACKGROUND: In the diabetic kidney, stimulation of mitogen-activated protein kinases (MAPKs) leads to extracellular matrix protein synthesis. In the proximal tubule, angiotensin-(1-7) [Ang-(1-7)] blocks activation of MAPKs by angiotensin II. We studied the effect of Ang-(1-7) on signalling responses in LLC-PK(1) cells in normal (5 mM) or high (25 mM) glucose. METHODS: The p38 MAPK was assayed by immunoblot, Src homology 2-containing protein-tyrosine phosphatase-1 (SHP-1) activity was measured after immunoprecipitation, cell protein synthesis was determined by [(3)H]-leucine incorporation and transforming growth factor-beta1 (TGF-beta1), fibronectin and collagen IV were assayed by immunoblots and/or ELISA. RESULTS: High glucose stimulated p38 MAPK. This response was inhibited by Ang-(1-7) in a concentration-dependent fashion, an effect reversed by the receptor Mas antagonist A-779. Ang-(1-7) increased SHP-1 activity, via the receptor Mas. An inhibitor of tyrosine phosphatase, phenylarsine oxide, reversed the inhibitory effect of Ang-(1-7) on high glucose-stimulated p38 MAPK. Ang-(1-7) inhibited high glucose-stimulated protein synthesis, and blocked the stimulatory effect of glucose on TGF-beta1. Conversely, Ang-(1-7) had no effect on glucose-stimulated synthesis of fibronectin or collagen IV. CONCLUSIONS: These data indicate that in proximal tubular cells, binding of Ang-(1-7) to the receptor Mas stimulates SHP-1, associated with the inhibition of glucose-stimulated p38 MAPK. Ang-(1-7) selectively inhibits glucose-stimulated protein synthesis and TGF-beta1. In diabetic nephropathy, Ang-(1-7) may partly counteract the profibrotic effects of high glucose.

Schistosoma mansoni tegument protein Sm29 is able to induce a Th1-type of immune response and protection against parasite infection.

BACKGROUND: Schistosomiasis continues to be a significant public health problem. This disease affects 200 million people worldwide and almost 800 million people are at risk of acquiring the infection. Although vaccine development against this disease has experienced more failures than successes, encouraging results have recently been obtained using membrane-spanning protein antigens from the tegument of Schistosoma mansoni. Our group recently identified Sm29, another antigen that is present at the adult worm tegument surface. In this study, we investigated murine cellular immune responses to recombinant (r) Sm29 and tested this protein as a vaccine candidate. METHODS AND FINDINGS: We first show that Sm29 is located on the surface of adult worms and lung-stage schistosomula through confocal microscopy. Next, immunization of mice with rSm29 engendered 51%, 60% and 50% reduction in adult worm burdens, in intestinal eggs and in liver granuloma counts, respectively (p<0.05). Protective immunity in mice was associated with high titers of specific anti-Sm29 IgG1 and IgG2a and elevated production of IFN-gamma, TNF-alpha and IL-12, a typical Th1 response. Gene expression analysis of worms recovered from rSm29 vaccinated mice relative to worms from control mice revealed a significant (q<0.01) down-regulation of 495 genes and up-regulation of only 22 genes. Among down-regulated genes, many of them encode surface antigens and proteins associated with immune signals, suggesting that under immune attack schistosomes reduce the expression of critical surface proteins. CONCLUSION: This study demonstrates that Sm29 surface protein is a new vaccine candidate against schistosomiasis and suggests that Sm29 vaccination associated with other protective critical surface antigens is the next logical strategy for improving protection.

Isoproterenol-induced impairment of heart function and remodeling are attenuated by the nonpeptide angiotensin-(1-7) analogue AVE 0991.

The aim of this study was to evaluate the effects of AVE 0991 (AVE), a nonpeptide compound that mimics Ang-(1-7) actions, on cardiac remodeling. Heart hypertrophy and heart dysfunction were induced by isoproterenol (ISO) (2 mg/kg i.p./day for 7 days) in male Wistar rats. At the end of the 7-day period, the hearts were perfused according to the Langendorff method to evaluate cardiac function. The hearts, atria, and right and left ventricles wet weights were recorded, normalized for body weight and then expressed as muscle mass index (mg/g). In addition, serial sections from left ventricle were stained with hematoxylin-eosin for cell morphometry and with collagen-specific Masson's trichrome for detection of fibrosis. Immunofluorescence-labeling and confocal microscopy were used to investigate the distribution and deposition of collagen types I, III, VI, and fibronectin. AVE reduced the ISO-induced hypertrophy as quantified by myocyte diameter measurements (Control: 10.60+/-0.08 microm; ISO: 14.60+/-0.11 mum; ISO+AVE: 11.22+/-0.08 microm, n = 5). In addition, AVE markedly attenuated the increase of extracellular matrix proteins induced by ISO. AVE treatment also attenuated the decrease in systolic tension and +/-dT/dt and exacerbated the vasodilatation induced by ISO. These results show that AVE has a cardioprotective effect on ISO-induced cardiac remodeling.

Impairment of in vitro and in vivo heart function in angiotensin-(1-7) receptor MAS knockout mice.

In this study we investigated the effects of the genetic deletion of the angiotensin (Ang)-(1-7) receptor Mas on heart function. Localization of Mas in the mouse heart was evaluated by binding of rhodamine-labeled Ang-(1-7). Cardiac function was examined using isolated heart preparations. Echocardiography was used to confirm the results obtained with isolated heart studies. To elucidate the possible mechanisms involved in the cardiac phenotype observed in Mas(-/-) mice, whole-cell calcium currents in cardiomyocytes and the expression of collagen types I, III, and VI and fibronectin were analyzed. Ang-(1-7) binding showed that Mas is localized in cardiomyocytes of the mouse heart. Isolated heart techniques revealed that Mas-deficient mice present a lower systolic tension (average: 1.4+/-0.09 versus 2.1+/-0.03 g in Mas(+/+) mice), +/-dT/dt, and heart rate. A significantly higher coronary vessel resistance was also observed in Mas-deficient mice. Echocardiography revealed that hearts of Mas-deficient mice showed a significantly decreased fractional shortening, posterior wall thickness in systole and left ventricle end-diastolic dimension, and a higher left ventricle end-systolic dimension. A markedly lower global ventricular function, as defined by a higher myocardial performance index, was observed. A higher delayed time to the peak of calcium current was also observed. The changes in cardiac function could be partially explained by a marked change in collagen expression to a profibrotic profile in Mas-deficient mice. These results indicate that Ang-(1-7)-Mas axis plays a key role in the maintenance of the structure and function of the heart.