The Triad Na+ Activated Na+ Channel (Nax)-Salt Inducible KINASE (SIK) and (Na+ + K+)-ATPase: Targeting the Villains to Treat Salt Resistant and Sensitive Hypertension.

The Na+-activated Na+ channel (Nax) and salt-inducible kinase (SIK) are stimulated by increases in local Na+ concentration, affecting (Na+ + K+)-ATPase activity. To test the hypothesis that the triad Nax/SIK/(Na+ + K+)-ATPase contributes to kidney injury and salt-sensitive hypertension (HTN), uninephrectomized male Wistar rats (200 g; n = 20) were randomly divided into 4 groups based on a salt diet (normal salt diet; NSD-0.5% NaCl-or high-salt diet; HSD-4% NaCl) and subcutaneous administration of saline (0.9% NaCl) or deoxycorticosterone acetate (DOCA, 8 mg/kg), as follows: Control (CTRL), CTRL-Salt, DOCA, and DOCA-Salt, respectively. After 28 days, the following were measured: kidney function, blood pressure, (Na+ + K+)-ATPase and SIK1 kidney activities, and Nax and SIK1 renal expression levels. SIK isoforms in kidneys of CTRL rats were present in the glomerulus and tubular epithelia; they were not altered by HSD and/or HTN. CTRL-Salt rats remained normotensive but presented slight kidney function decay. HSD rats displayed augmentation of the Nax/SIK/(Na+ + K+)-ATPase pathway. HTN, kidney injury, and kidney function decay were present in all DOCA rats; these were aggravated by HSD. DOCA rats presented unaltered (Na+ + K+)-ATPase activity, diminished total SIK activity, and augmented SIK1 and Nax content in the kidney cortex. DOCA-Salt rats expressed SIK1 activity and downregulation in (Na+ + K+)-ATPase activity in the kidney cortex despite augmented Nax content. The data of this study indicate that the (Na+ + K+)-ATPase activity response to SIK is attenuated in rats under HSD, independent of HTN, as a mechanism contributing to kidney injury and salt-sensitive HTN.

Saccharomyces boulardii modulates oxidative stress and renin angiotensin system attenuating diabetes-induced liver injury in mice.

Type 1 diabetes (T1DM) is a chronic disease characterized by hyperglycemia due to a deficiency in endogenous insulin production, resulting from pancreatic beta cell death. Persistent hyperglycemia leads to enhanced oxidative stress and liver injury. Several studies have evaluated the anti-diabetic and protective effects of probiotic strains in animal models. In the present study, we investigated, through histopathological and biochemical analyses, the effects of eight weeks of administration of Saccharomyces boulardii (S. boulardii) yeast on the liver of streptozotocin (STZ) induced diabetic C57BL/6 mice. Our results demonstrated that S. boulardii attenuates hepatocytes hydropic degeneration and hepatic vessels congestion in STZ-induced diabetic mice. The treatment attenuated the oxidative stress in diabetic mice leading to a reduction of carbonylated protein concentration and increased activity of antioxidant enzymes superoxide dismutase and glutathione peroxidase, compared to untreated diabetic animals. The results also show the beneficial influence of S. boulardii in regulating the hepatic concentration of renin angiotensin system (RAS) peptides. Therefore, our results demonstrated that S. boulardii administration to STZ-induced diabetic mice reduces oxidative stress and normalizes the concentration of RAS peptides, supporting the hypothesis that this yeast may have a role as a potential adjunctive therapy to attenuate diabetes-induced liver injury.

Both aldosterone and spironolactone can modulate the intracellular ACE/ANG II/AT1 and ACE2/ANG (1-7)/MAS receptor axes in human mesangial cells.

The kidney is an important target of the renin-ANG-aldosterone system (RAAS). To date, several studies have demonstrated the existence of a local RAAS in various tissues, including the renal tissue. The mineralocorticoid aldosterone is known to play a critical role in the classical RAAS; however, its effect on mesangial cells (MCs) remains to be elucidated. Based on this, our aim was to investigate whether aldosterone stimulation can modulate the intracellular RAAS of immortalized human MCs by evaluating ANG-converting enzyme (ACE)/ANG II/ANG II receptor type 1 (AT1) and ANG-converting enzyme 2 (ACE2)/ANG (1-7)/MAS receptor axes. To realise this, protein expression, enzyme activity, and immunofluorescence were performed under aldosterone stimulation and in the presence of the mineralocorticoid receptor (MR) antagonist spironolactone (SPI). We observed that high doses of aldosterone increase ACE activity. The effect of aldosterone on the catalytic activity of ACE was completely abolished with the pretreatment of SPI suggesting that the aldosterone-induced cell injuries through ANG II release were attenuated. Aldosterone treatment also decreased the expression of MAS receptor, but did not alter the expression or the catalytic activity of ACE 2 and ANG (1-7) levels. Spironolactone modulated the localization of ANG II and AT1 receptor and decreased ANG (1-7) and MAS receptor levels. Our data suggest that both aldosterone and the MR receptor antagonist can modulate both of these axes and that spironolactone can protect MCs from the damage induced by aldosterone.

Modulation of renin angiotensin system components by high glucose levels in the culture of collecting duct cells.

Diabetes mellitus and its complications have become a major health concern in Western countries. Increased activity of the intrarenal renin-angiotensin system (RAS) contributes to diabetic nephropathy (DN). We previously reported that in mesangial cells, the high glucose concentration (HG) leads to upregulation of angiotensin-converting enzyme (ACE) messenger RNA, suggesting that ACE was modulated by angiotensin II (Ang II) release. However, this relation in the collecting duct has not yet been studied. We, therefore, aimed to evaluate RAS modulation in inner medullary collecting duct cells (IMCD) exposed to HG. The IMCD were divided into normal glucose (5 mM D-glucose, NG), high glucose (30 mM, HG), and mannitol (30 mM, M) groups. The cells were cultured 48 hr in their respective media. The intracellular and extracellular ACE activity was measured using hippuryl-His-Leu as substrate via a fluorimetric assay and expression was analyzed using western blot analysis. ACE activity, intracellular (27%) and extracellular (22%), was significantly lower in the HG group than in NG and M. ACE2 activity and Ang 1-7 levels were higher in the intracellular compartment. Our data suggest that the HG cannot modify ACE synthesis in IMCD cells but can modulate its activity. The decrease in ACE activity may result in decreased levels of Ang II to protect the IMCD against proliferative and inflammatory deleterious effects of this peptide. Conversely, the increase of ACE2 generating high levels of Ang 1-7, a vasodilator peptide, suggesting that this peptide can induce glucose uptake and protect cells against oxidative stress, which can elicit insulin resistance.

Kinin-B2 Receptor Activity in Skeletal Muscle Regeneration and Myoblast Differentiation.

The bioactive peptide bradykinin obtained from cleavage of precursor kininogens activates the kinin-B2 receptor functioning in induction of inflammation and vasodilatation. In addition, bradykinin participates in kidney and cardiovascular development and neuronal and muscle differentiation. Here we show that kinin-B2 receptors are expressed throughout differentiation of murine C2C12 myoblasts into myotubes. An autocrine loop between receptor activation and bradykinin secretion is suggested, since bradykinin secretion is significantly reduced in the presence of the kinin-B2 receptor antagonist HOE-140 during differentiation. Expression of skeletal muscle markers and regenerative capacity were decreased after pharmacological inhibition or genetic ablation of the B2 receptor, while its antagonism increased the number of myoblasts in culture. In summary, the present work reveals to date no functions described for the B2 receptor in muscle regeneration due to the control of proliferation and differentiation of muscle precursor cells.

Circulating catecholamines are associated with biobehavioral factors and anxiety symptoms in head and neck cancer patients.

Studies have shown that stress-related catecholamines may affect cancer progression. However, little is known about catecholamine secretion profiles in head and neck cancer patients. The present study investigated plasma norepinephrine and epinephrine levels in head and neck squamous cell carcinoma (HNSCC) patients and patients with oral leukoplakia, as well as their association with clinicopathological and biobehavioral variables and anxiety symptoms. A total of 93 patients with HNSCC and 32 patients with oral leukoplakia were included. Plasma norepinephrine and epinephrine levels were measured by high performance liquid chromatography with electrochemical detection (HPLC-ED), and psychological anxiety levels were measured by the Beck Anxiety Inventory (BAI). Plasma norepinephrine and epinephrine concentrations were significantly higher in patients with oral and oropharyngeal squamous cell carcinoma (SCC) compared to non-cancer patients. Oral SCC patients displayed plasma norepinephrine levels about six times higher than oropharyngeal SCC patients, and nine times higher than oral leukoplakia patients (p < .001). Plasma epinephrine levels in oral SCC patients were higher compared to the oropharyngeal SCC (p = .0097) and leukoplakia (p < .0001) patients. Oropharyngeal SCC patients had higher plasma norepinephrine (p = .0382) and epinephrine levels (p = .045) than patients with oral leukoplakia. Multiple regression analyses showed that a history of high alcohol consumption was predictive for reduced plasma norepinephrine levels in the oral SCC group (p < .001). Anxiety symptom of "hand tremor" measured by the BAI was an independent predictor for higher plasma norepinephrine levels in HNSCC patients (ß = 157.5, p = .0377), while the "heart pounding/racing" symptom was independently associated with higher plasma epinephrine levels in the oropharyngeal SCC group (ß = 15.8, p = .0441). In oral leukoplakia patients, sleep deprivation and worse sleep quality were independent predictors for higher plasma norepinephrine levels, while severe tobacco consumption and higher anxiety levels were factors for higher plasma epinephrine levels. These findings suggest that head and neck cancer patients display sympathetic nervous system hyperactivity, and that changes in circulating catecholamines may be associated with alcohol consumption, as well as withdrawal-related anxiety symptoms.

The binding of captopril to angiotensin I-converting enzyme triggers activation of signaling pathways.

Hypertension is a global health problem, and angiotensin I (ANG I)-converting enzyme (ACE) inhibitors are largely used to control this pathology. Recently, it has been shown that ACE can also act as a transducer signal molecule when its inhibitors or substrates bind to it. This new role of ACE could contribute to understanding some of the effects not explained by its catalytic activity only. In this study, we investigated signaling pathway activation in Chinese hamster ovary (CHO) cells stably expressing ACE (CHO-ACE) under different conditions. We also investigated gene modulation after 4 h and 24 h of captopril treatment. Our results demonstrated that CHO-ACE cells when stimulated with ANG I, ramipril, or captopril led to JNK and ERK1/2 phosphorylation. To verify any physiological role at the endogenous level, we made use of primary cultures of mesangial cells from spontaneously hypertensive rats (SHR) and Wistar rats. Our results showed that ERK1/2 activation occurred mainly in primary cultures of mesangial cells from SHR rats upon captopril stimulation, suggesting that this signaling pathway could be differentially regulated during hypertension. Our results also showed that captopril treatment leads to a decrease of cyclooxygenase 2, interleukin-1ß, and ß-arrestin2 and a significant increase of AP2 gene expression levels. Our findings strengthen the fact that, in addition to the blockage of enzymatic activity, ACE inhibitors also trigger signaling pathway activation, and this may contribute to their beneficial effects in the treatment of hypertension and other pathologies.

Nebivolol prevents vascular oxidative stress and hypertension in rats chronically treated with ethanol.

BACKGROUND AND AIMS: Chronic ethanol consumption is associated with hypertension and atherosclerosis. Vascular oxidative stress is described as an important mechanism whereby ethanol predisposes to atherosclerosis. We hypothesized that nebivolol would prevent ethanol-induced hypertension and vascular oxidative stress. METHODS: Male Wistar rats were treated with ethanol 20% (vol./vol.) or nebivolol (10 mg/kg/day, p. o., gavage), a selective ß1-adrenergic receptor antagonist. RESULTS: Ethanol-induced increase in blood pressure and in the circulating levels of adrenaline and noradrenaline was prevented by nebivolol. Similarly, nebivolol prevented ethanol-induced increase in plasma levels of renin, angiotensin I and II. Chronic ethanol consumption increased the aortic levels of superoxide anion (O2-), thiobarbituric acid reactive species (TBARS) as well as the expression of Nox1 and nitrotyrosine immunostaining in the rat aorta. Treatment with nebivolol prevented these responses. The decrease in aortic levels of nitrate/nitrite (NOx) induced by ethanol was prevented by the treatment with nebivolol. Finally, nebivolol attenuated ethanol-induced increase in phenylephrine- and noradrenaline-induced contraction of endothelium-intact and endothelium-denuded aortic rings. CONCLUSIONS: The novelty of our study is that nebivolol prevented ethanol-induced hypertension and vascular oxidative stress. Additionally, we showed that the sympathetic nervous system (SNS) and the renin-angiotensin system (RAS) are important endogenous mediators of the cardiovascular effects of ethanol.

Ethanol withdrawal increases blood pressure and vascular oxidative stress: a role for angiotensin type 1 receptors.

We evaluated the possible mechanisms underlying the oxidative stress induced by ethanol withdrawal. With this purpose, we verified the role of AT1 receptors in such response. Male Wistar rats were treated with ethanol 3%-9% (vol./vol.) for 21 days. Ethanol withdrawal was induced by abrupt discontinuation of the treatment. Experiments were performed 48 hours after ethanol discontinuation. Increased plasma levels of angiotensin II were detected after ethanol withdrawal. Losartan (10 mg/kg; p.o. gavage), a selective AT1 receptor antagonist, impeded the increase in blood pressure induced by ethanol withdrawal. Increased lipoperoxidation and superoxide anion (O2-) levels were detected in aortas after ethanol withdrawal, and losartan prevented these responses. Decreased hydrogen peroxide and nitrate/nitrite concentration were detected in aortas after ethanol withdrawal, and losartan prevented these effects. Nitrotyrosine immunostaining in the rat aorta was increased after ethanol withdrawal, and AT1 blockade impeded this response. Increased expression of PKCδ and p47phox was detected after ethanol withdrawal, and treatment with losartan prevented these responses. Our study provides novel evidence that ethanol withdrawal increases vascular oxidative stress and blood pressure through AT1-dependent mechanisms. These findings highlight the importance of angiotensin II in ethanol withdrawal-induced increase in blood pressure and vascular oxidative damage.

Direct renin inhibition is not enough to prevent reactive oxygen species generation and vascular dysfunction in renovascular hypertension.

Renin-angiotensin system activation promotes oxidative stress and endothelial dysfunction. However, no previous study has examined the effects of the renin inhibitor aliskiren, either alone or combined with angiotensin II type 1 antagonists on alterations induced by two-kidney, one-clip (2K1C) hypertension. We compared the vascular effects of aliskiren (50mg/kg/day), losartan (10mg/kg/day), or both by gavage for 4 weeks in 2K1C and control rats. Treatment with losartan, aliskiren, or both exerted similar antihypertensive effects. Aliskiren lowered plasma Ang I concentrations in sham rats and in hypertensive rats treated with aliskiren or with both drugs. Aliskiren alone or combined with losartan decreased plasma angiotensin II concentrations measured by high performance liquid chromatography, whereas losartan alone had no effects. In contrast, losartan alone or combined with aliskiren abolished hypertension-induced increases in aortic angiotensin II concentrations, whereas aliskiren alone exerted no such effects. While hypertension enhanced aortic oxidative stress assessed by dihydroethidium fluorescence and by lucigenin chemiluminescence, losartan alone or combined with aliskiren, but not aliskiren alone, abolished this alteration. Hypertension impaired aortic relaxation induced by acetylcholine, and losartan alone or combined with aliskiren, but not aliskiren alone, reversed this alteration. Losartan alone or combined with aliskiren, but not aliskiren alone, increased plasma nitrite concentrations in 2K1C rats. These findings show that antihypertensive effects of aliskiren do not prevent hypertension-induced vascular oxidative stress and endothelial dysfunction. These findings contrast those found with losartan and suggest that renin inhibition is not enough to prevent hypertension-induced impaired redox biology and vascular dysfunction.

Temporal changes in cardiac oxidative stress, inflammation and remodeling induced by exercise in hypertension: Role for local angiotensin II reduction.

Exercise training reduces renin-angiotensin system (RAS) activation, decreases plasma and tissue oxidative stress and inflammation in hypertension. However, the temporal nature of these phenomena in response to exercise is unknown. We sought to determine in spontaneously hypertensive rats (SHR) and age-matched WKY controls the weekly effects of training on blood pressure (BP), plasma and left ventricle (LV) Ang II and Ang-(1-7) content (HPLC), LV oxidative stress (DHE staining), gene and protein expression (qPCR and WB) of pro-inflammatory cytokines, antioxidant enzymes and their consequence on hypertension-induced cardiac remodeling. SHR and WKY were submitted to aerobic training (T) or maintained sedentary (S) for 8 weeks; measurements were made at weeks 0, 1, 2, 4 and 8. Hypertension-induced cardiac hypertrophy was accompanied by acute plasma Ang II increase with amplified responses during the late phase of LV hypertrophy. Similar pattern was observed for oxidative stress markers, TNF alpha and interleukin-1ß, associated with cardiomyocytes' diameter enlargement and collagen deposition. SHR-T exhibited prompt and marked decrease in LV Ang II content (T1 vs T4 in WKY-T), normalized oxidative stress (T2), augmented antioxidant defense (T4) and reduced both collagen deposition and inflammatory profile (T8), without changing cardiomyocytes' diameter and LV hypertrophy. These changes were accompanied by decreased plasma Ang II content (T2-T4) and reduced BP (T8). SHR-T and WKY-T showed parallel increases in LV and plasma Ang-(1-7) content. Our data indicate that early training-induced downregulation of LV ACE-AngII-AT1 receptor axis is a crucial mechanism to reduce oxidative/pro-inflammatory profile and improve antioxidant defense in SHR-T, showing in addition this effect precedes plasma RAS deactivation.

Association between Diastolic Dysfunction with Inflammation and Oxidative Stress in Females ob/ob Mice.

Objective: To evaluate autonomic and cardiovascular function, as well as inflammatory and oxidative stress markers in ob/ob female mice. Methods: Metabolic parameters, cardiac function, arterial pressure (AP), autonomic, hormonal, inflammatory, and oxidative stress markers were evaluated in 12-weeks female wild-type (WT group) and ob/ob mice (OB group). Results: OB animals showed increased body weight, blood glucose, and triglyceride levels, along with glucose intolerance, when compared to WT animals. Ejection fraction (EF) and AP were similar between groups; however, the OB group presented diastolic dysfunction, as well as an impairment on myocardial performance index. Moreover, the OB group exhibited important autonomic dysfunction and baroreflex sensitivity impairment, when compared to WT group. OB group showed increased Angiotensin II levels in heart and renal tissues; decreased adiponectin and increased inflammatory markers in adipose tissue and spleen. Additionally, OB mice presented a higher damage to proteins and lipoperoxidation and lower activity of antioxidant enzymes in kidney and heart. Correlations were found between autonomic dysfunction with angiotensin II and inflammatory mediators, as well as between inflammation and oxidative stress. Conclusions: Our results showed that female adult ob/ob mice presented discrete diastolic dysfunction accompanied by autonomic disorder, which is associated with inflammation and oxidative stress in these animals.

Reduced Sympathetic Stimulus and Angiotensin 1-7 Are Related to Diastolic Dysfunction in Spinal Cord-Injured Subjects.

Chronic spinal cord injury (SCI) is often associated with reductions in left ventricular (LV) diastolic function. Impairments in sympathetic activity and activation of the renin-angiotensin system are reported in SCI individuals and may hypothetically be implicated in this association. Hence, the present study verified the relationship between these two neuro-hormonal and cardiac functional and structural characteristics in SCI individuals. Twenty-two men with SCI (injury level above T6 and no voluntary motion below the injury) and 11 able-bodied men were evaluated by clinical, hemodynamic, laboratory, and echocardiographic analysis and had plasmatic renin, angiotensin I (ANGI), angiotensin II (ANGII), angiotensin 1-7 (ANG1-7), and noradrenaline levels measured. SCI subjects had lower noradrenaline (p = 0.003) and higher ANG1-7 (p = 0.009), but similar renin, ANGI, and ANGII levels when compared with able-bodied individuals. In SCI individuals, results of multi-variable analysis showed that higher Em, a marker of better LV diastolic function, was directly associated with ANG1-7 (p = 0.05) or ANG1-7/ANGII ratio (p = 0.007), whereas lower noradrenaline levels were independently associated with worse LV diastolic function, as assessed by E/Em ratio (p = 0.028). In conclusion, these results suggest that reduced sympathetic activity and expression of ANG1-7 may be involved in SCI-related diastolic dysfunction.

90-kDa N-domain angiotensin I-converting enzyme (ACE): possible marker for hypertension in a renal transplant model.

INTRODUCTION: Hypertension is nearly universal in kidney transplant and several factors are associated with post transplant hypertension, including immunosuppressive medications and genetic predisposition. OBJECTIVE: The aims were to evaluate the effects of spontaneously hypertensive rats (SHR) kidney transplantation in Wistar rats and the possible transference of 80/90-kDa N-domain ACE. METHODS: To do so, the data from Wistar recipients of kidney from SHR were compared to data from transplanted Wistar submitted to CsA treatment and, to Wistar Sham. RESULTS AND DISCUSSION: Despite the unaltered blood pressure observed at early stages, 80/90-kDa ACE was found expressed in the urine of rats 7 and 15 days after transplantation, which was intense when rats became hypertensive 30 days post-surgery. CONCLUSION: Our data show that this enzyme is associated with the development of hypertension, and this marker appears in the urine before any substantial blood pressure alteration.

90-kDa N-domain angiotensin I-converting enzyme (ACE): possible marker for hypertension in a renal transplant model / Enzima conversora de angiotensina I (ECA) N-domínio 90-kDa: possível marcador para hipertensão em modelo de transplante renal

Abstract Introduction: Hypertension is nearly universal in kidney transplant and several factors are associated with post transplant hypertension, including immunosuppressive medications and genetic predisposition. Objective: The aims were to evaluate the effects of spontaneously hypertensive rats (SHR) kidney transplantation in Wistar rats and the possible transference of 80/90-kDa N-domain ACE. Methods: To do so, the data from Wistar recipients of kidney from SHR were compared to data from transplanted Wistar submitted to CsA treatment and, to Wistar Sham. Results and Discussion: Despite the unaltered blood pressure observed at early stages, 80/90-kDa ACE was found expressed in the urine of rats 7 and 15 days after transplantation, which was intense when rats became hypertensive 30 days post-surgery. Conclusion: Our data show that this enzyme is associated with the development of hypertension, and this marker appears in the urine before any substantial blood pressure alteration.

Resumo Introdução: A hipertensão é altamente prevalente pós-transplante renal e vários fatores estão associados incluindo o tratamento com imunossupressores e a predisposição genética. Objetivo: Os objetivos foram avaliar os efeitos do transplante do rim de ratos espontaneamente hipertensos (SHR) em ratos Wistar, e a possível transferência da ECA N-domínio de 80/90-kDa para os tecidos dos receptores. Métodos: Para isso, os dados dos animais Wistar receptores dos rins de SHR foram comparados aos dados dos Wistar submetidos ao tratamento com CsA e Wistar Sham. Resultados e Discussão: Apesar da pressão arterial permanecer inalterada nos estágios iniciais pós-transplante renal, a expressão da ECA de 80/90-kDa foi identificada na urina de ratos 7 e 15 dias após o transplante, e de forma mais intensa aos 30 dias após a cirurgia, quando os animais tornaram-se hipertensos. Conclusão: Nossos dados mostram que ECA N-domínio está associada ao desenvolvimento da hipertensão, e que este marcador pode ser identificado na urina pós-transplante renal antes mesmo de qualquer alteração da pressão arterial.

Plasma proteomics for the assessment of acute renal transplant rejection.

Renal transplant is the best treatment for patients with chronical kidney disease however acute graft rejection is the major impediment to success in renal transplantation leading to loss of the organ the first year after transplantation. The aim of this study was to identify plasma proteins that may be early biomarkers of acute rejection of renal allograft, developing a diagnostic model that avoids the loss of the transplanted organ. Shotgun proteomics (LC-MS/MS) method was used to analyze a set of thirty-one plasma samples, including 06 from patients with acute graft rejection after transplantation (rejection group/Rej-group) and twenty-five from renal transplant patients with stable renal graft function (control group/Ct-group). As results nineteen proteins were upregulated in the rejection group compared to the control group, and two proteins were downregulated; and three were present exclusively in the rejection group. After analysis, we selected four proteins that were related to the acute phase response and that were strongly associated with each other: they are alpha-1 antitrypsin (A1AT), alpha-2 antiplasmin (A2AP), serum amyloid A (SAA) and apolipoprotein CIII (APOC3). We think that simultaneous monitoring of SAA and APOC3 can provide insights into a broad profile of signaling proteins and is highly valuable for the early detection of a possible acute renal graft rejection. STATEMENT OF SIGNIFICANCE OF THE STUDY: In this study we did plasma shotgun patients with and without acute rejection of renal allograft. In a clinical setting an acute rejection is typically suspected upon an increase in plasma creatinine and renal biopsy. But these methods are late and unspecific; sometimes the rejection process is already advanced when there is an increase in serum creatinine. Therefore, it is necessary to find proteins that can predict the allograft rejection process. In our study were able to identify changes in the concentration of plasma protein belonging to a network of protein interaction processes the acute phase response. We believe, therefore, that development of a routine diagnosis of these proteins can detect early acute rejection of renal allograft process, thus preventing its loss.

Reactive oxygen species contribute to dysfunction of bone marrow hematopoietic stem cells in aged C57BL/6 J mice.

BACKGROUND: Stem cells of intensely regenerative tissues are susceptible to cellular damage. Although the response to this process in hematopoietic stem cells (HSCs) is crucial, the mechanisms by which hematopoietic homeostasis is sustained are not completely understood. Aging increases reactive oxygen species (ROS) levels and inflammation, which contribute to increased proliferation, senescence and/or apoptosis, leading to self-renewal premature exhaustion. In this study, we assessed ROS production, DNA damage, apoptosis, senescence and plasticity in young, middle and aged (2-, 12- and 24-month-old, respectively) C57BL/6 J mice. RESULTS: Aged HSCs showed an increase in intracellular superoxide anion (1.4-fold), hydrogen peroxide (2-fold), nitric oxide (1.6-fold), peroxynitrite/hidroxil (2.6-fold) compared with young cells. We found that mitochondria and NADPHox were the major sources of ROS production in the three groups studied, whereas CYP450 contributed in middle and aged, and xanthine oxidase only in aged HSCs. In addition, we observed DNA damage and apoptosis in the middle (4.2- and 2-fold, respectively) and aged (6- and 4-fold, respectively) mice; aged mice also exhibited a significantly shorter telomere length (-1.8-fold) and a lower expression of plasticity markers. CONCLUSION: These data suggest that aging impairs the functionality of HSCs and that these age-associated alterations may affect the efficacy of aged HSC recovery and transplantation.

Characterization of the renal renin-angiotensin system in transgenic mice that express rat tonin.

INTRODUCTION: Tonin is an enzyme that is able to generate angiotensin II (Ang II) from angiotensin I (Ang I) or directly from angiotensinogen. Our goal was to characterize the renal renin-angiotensin system in transgenic mice that express rat tonin (TGM`(rTon)). MATERIALS AND METHODS: Mice were euthanized and the kidneys removed for analysis. Tonin activity was evaluated by radioimmunoassay and angiotensin I-converting enzyme (ACE) activity by HPLC. Tonin, ACE and angiotensin II-converting enzyme (ACE2) expression was analyzed by Western blotting. RESULTS: Tonin activity was significantly increased in TGM`(rTon) compared to their respective wild-type (WT) littermates (1.7 ± 0.21 vs 0.11 ± 0.02 nmol of Ang II/min/mg of protein). Tonin activity had a strong positive correlation with tonin expression in both TGM`(rTon) and their respective wild-type littermates. The ACE activity and expression levels of 65-kDa N-domain angiotensin I-converting enzyme isoform were significantly increased in the TGM`(rTon) when compared with WT. ACE2 expression levels were statistically significantly higher in the TGM`(rTon) when compared with WT. Angiotensin 1-7 (Ang(1-7)) and Ang I levels were significantly lower in the TGM`(rTon). CONCLUSIONS: We suggest that the environment of tonin abundance may increase N-domain ACE activity liberated by a secretase able to cleave somatic ACE.

Post-Exercise Hypotension and Its Mechanisms Differ after Morning and Evening Exercise: A Randomized Crossover Study.

Post-exercise hypotension (PEH), calculated by the difference between post and pre-exercise values, it is greater after exercise performed in the evening than the morning. However, the hypotensive effect of morning exercise may be masked by the morning circadian increase in blood pressure. This study investigated PEH and its hemodynamic and autonomic mechanisms after sessions of aerobic exercise performed in the morning and evening, controlling for responses observed after control sessions performed at the same times of day. Sixteen pre-hypertensive men underwent four sessions (random order): two conducted in the morning (7:30 am) and two in the evening (5 pm). At each time of day, subjects underwent an exercise (cycling, 45 min, 50%VO2peak) and a control (sitting rest) session. Measurements were taken pre- and post-interventions in all the sessions. The net effects of exercise were calculated for each time of day by [(post-pre exercise)-(post-pre control)] and were compared by paired t-test (P<0.05). Exercise hypotensive net effects (e.g., decreasing systolic, diastolic and mean blood pressure) occurred at both times of day, but systolic blood pressure reductions were greater after morning exercise (-7±3 vs. -3±4 mmHg, P<0.05). Exercise decreased cardiac output only in the morning (-460±771 ml/min, P<0.05), while it decreased stroke volume similarly at both times of day and increased heart rate less in the morning than in the evening (+7±5 vs. +10±5 bpm, P<0.05). Only evening exercise increased sympathovagal balance (+1.5±1.6, P<0.05) and calf blood flow responses to reactive hyperemia (+120±179 vs. -70±188 U, P<0.05). In conclusion, PEH occurs after exercise conducted at both times of day, but the systolic hypotensive effect is greater after morning exercise when circadian variations are considered. This greater effect is accompanied by a reduction of cardiac output due to a smaller increase in heart rate and cardiac sympathovagal balance.

Cecropia pachystachya extract attenuated the renal lesion in 5/6 nephrectomized rats by reducing inflammation and renal arginase activity.

ETHNOPHARMACOLOGICAL RELEVANCE: The plant Cecropia pachystachya Trécul has been used in Brazilian folk medicine to treat hypertension, bladder and kidney inflammation and renal diseases. The aim of this study was to evaluate the potential of the aqueous fraction from the ethanolic extract of Cecropia pachystachya (FCP) in the management of hypertension, inflammation and progressive renal disease in rats submitted to 5/6 nephrectomy. MATERIALS AND METHODS: Thirty male Wistar rats submitted to 5/6 nephrectomy (5/6 NE) were untreated (NE) or treated (NE+FCP) with the FCP (0.5g/kg/day). The treatment started 15 days after surgery, and the rats were followed for a period of 60 days. Systolic blood pressure (SBP) and albuminuria were evaluated from 15-60 days after the surgical procedure. Function and estructural renal changes, TGF-ß (transforming growth factor ß), MCP-1 (monocyte chemoattractant protein-1) and nitric oxide (NO) urinary excretion were analyzed. Expression and activity of the renal enzymes arginase (ARG), angiotensin converting enzyme (ACE), and MAP kinase p-JNK expression also were analyzed. RESULTS: The nephrectomized rats developed progressive albuminuria and increased SBP that was less intense in the treated group. There was a reduction in the glomerular filtration rate (GFR) in the nephrectomized rats, which was attenuated by treatment with FCP extract. The treatment with FCP also attenuated the histological changes, reduced the expression and activity of renal arginase, the number of macrophages (ED-1 positive cells) and the p-JNK expression in the renal cortex of the rats submitted to 5/6 NE. The urinary excretion of TGF-ß was less intense in the treated group and was associated with the reduction of the expression and activity of the renal arginase. CONCLUSIONS: These results suggest that the reduction of renal arginase activity, p-JNK and TGF-ß expression can explain the mechanism by which the treatment with C. pachystachya reduced the inflammation and improved renal function. This study presents the potential use of Cecropia pachystachya in the treatment of chronic renal diseases.