Fernanda Aparecida Ronchi

Chronic conventional resistance exercise reduces blood pressure in stage 1 hypertensive men.

Abstract Moraes, MR, Bacurau, RFP, Casarini, DE, Jara, ZP, Ronchi, FA, Almeida, SS, Higa, EMS, Pudo, MA, Rosa, TS, Haro, AS, Barros, CC, Pesquero, JB, Würtele, M, and Araujo, RC. Chronic conventional resistance exercise reduces blood pressure in stage 1 hypertensive men. J Strength Cond Res 26(4): 1122–1129, 2012—To investigate the antihypertensive effects of conventional resistance exercise (RE) on the blood pressure (BP) of hypertensive subjects, 15 middle-aged (46 ± 3 years) hypertensive volunteers, deprived of antihypertensive medication (reaching 153 ± 6/93 ± 2 mm Hg systolic/diastolic BP after a 6-week medication washout period) were submitted to a 12-week conventional RE training program (3 sets of 12 repetitions at 60% 1 repetition maximum, 3 times a week on nonconsecutive days). Blood pressure was measured in all phases of the study (washout, training, detraining). Additionally, the plasma levels of several vasodilators or vasoconstrictors that potentially could be involved with the effects of RE on BP were evaluated pre- and posttraining. Conventional RE significantly reduced systolic, diastolic, and mean BP, respectively, by an average of 16 (p < 0.001), 12 (p < 0.01), and 13 mm Hg (p < 0.01) to prehypertensive values. There were no significant changes of vasoactive factors from the kallikrein-kinin or renin-angiotensin systems. After the RE training program, the BP values remained stable during a 4-week detraining period. Taken together, this study shows for the first time that conventional moderate-intensity RE alone is able to reduce the BP of stage 1 hypertensive subjects free of antihypertensive medication. Moreover, the benefits of BP reduction achieved with RE training remained unchanged for up to 4 weeks without exercise.

Expression of angiotensin I-converting enzymes and bradykinin B2 receptors in mouse inner medullary-collecting duct cells

We described in mouse inner medullary-collecting duct cells (mIMCD-3) the somatic and the N-domain ACE synthesis and its interaction with the kallikrein-kinin system co-localized in the same cells. We purified two ACE forms from culture medium, M1 (130 kDa) and M2 (N-domain, 60 kDa), and cellular lysate, C1 (130 kDa) and C2 (N-domain, 60 kDa). Captopril and enalaprilat inhibited the purified enzymes. The immunofluorescence studies indicated that ACE is present in the membrane, cytoplasm and in the cell nucleus. Kinin B1 and B2 receptors were detected by immunofluorescence and showed to be activated by BK and DesR9 BK, increasing the acidification rate which was enhanced in the presence of enalaprilat. The presence of secreted and intracellular ACE in mIMCD-3 confirmed the hypothesis previously proposed by our group for a new site of ACE secretion in the collecting duct.

Association of somatic and N-domain angiotensin-converting enzymes from Wistar rat tissue with renal dysfunction in diabetes mellitus.

Diabetes mellitus (DM) is characterised by alterations in the intrarenal renin-angiotensin system (RAS). Insulin treatment may reverse these changes by an unknown mechanism. We aimed to verify the association between somatic ACE with 136 kDa (sACE) and N-domain ACE with 69 kDa (nACE) from Wistar (W) rat tissue with DM.Three groups were studied: control (CT), insulin treated diabetic (DT) and untreated (D). ACE activity was determined using Hippuryl-His-Leu and Z-Phe-His-Leu as substrates. In D group, urine ACE activity increased for both substrates when compared with CT and DT, despite the decreased activity of renal tissues. Immunostaining of renal tissue demonstrated that ACE is more strongly expressed in the proximaltubule of D than in the same nephron portion in the other groups. Angiotensin (Ang) 1-7 and Ang II are less expressed in DT group when compared with CT and D. Ang II levels decreased in the D and DT groups showed when compared to the control. Ang 1-7 was detected in all studied groups with low levels in DT.The modulation of angiotensin peptides suggests that sACE, nACE, ACE 2 and NEP could have important functions in renal RAS regulation through a counter-regulatory mechanism to protect the kidney in diabetes mellitus.

N-domain angiotensin-converting enzyme isoform expression in tissues of Wistar and spontaneously hypertensive rats.

Background Angiotensin I-converting enzyme (ACE) is a protein containing two active sites, called N- and C-domains, according to their position in the protein. Aim The aim of the present study was to verify whether the expression of the N-domain ACEs detected in the urine of Wistar and spontaneously hypertensive (SHR) rats was restricted to the kidney. Methods Adrenal, aorta, heart, liver, lung, kidney and testicle tissue from Wistar rats and spontaneously hypertensive rats were homogenized in assay buffer and analyzed by gel filtration, Western blotting and radio-immunoassay. Results Two peaks (at 136 and 69 kDa) with ACE activity upon ZPhe-His-Leu were separated by gel filtration from homogenate tissues of Wistar rats, in contrast with the tissue from hypertensive rats, which showed ACE forms of 96 and 69 kDa. The bands detected by Western blotting for all studied tissue from Wistar and spontaneously hypertensive rats showed a correspondence with the two peaks containing ACE activity detected in the polyacrylamide gel slices. Angiotensin II levels were increased in hypertensive rat tissue when compared with Wistar rat tissues. In addition, captopril 3 μmol/l inhibited the enzymic activity, where the Km was in the order of mmol/l and μmol/l using hippuryl-His–Leu and Abz-Ser-Asp-Lys(Dnp)Pro-OH as substrates, respectively. All tissues from Wistar rats presented ACE with 136 kDa, similar to somatic ACE, and N-domain ACE with 69 kDa. In the same tissue of spontaneously hypertensive rats, 96 and 69 kDa N-domain ACEs were detected. Conclusions Our results demonstrated that N-domain ACEs were not exclusively produced in the kidney and excreted in the urine; they were expressed in all tissue studied, suggesting that these enzymes could influence local angiotensin II production, contributing to organ-specific regulation.

N-domain isoform of Angiotensin I converting enzyme as a marker of hypertension: populational study.

The aim of this paper was to investigate the presence of the urinary 90 kDa N-domain ACE in a cohort of the population from Vitoria, Brazil, to verify its association with essential hypertension since this isoform could be a possible genetic marker of hypertension. Anthropometric, clinical, and laboratory parameters of the individuals were evaluated (n = 1150) and the blood pressure (BP) was measured. The study population was divided according to ACE isoforms in urine as follows: ACE 65/90/190, presence of three ACE isoforms (n = 795), ACE 90+ (65/90) (n = 186), and ACE 90− (65/190) (n = 169) based on the presence (+) or absence (−) of the 90 kDa ACE isoform. The anthropometric parameters, lipid profile, serum levels of uric acid, glucose, and the systolic and diastolic BP were significantly greater in the ACE 90+ compared with the ACE 90− and ACE 65/90/190 individuals. We found that 98% of individuals from the ACE 90+ group and 38% from the ACE 65/90/190 group had hypertension, compared to only 1% hypertensive individuals in the ACE 90− group. There is a high presence of the 90 kDa N-domain ACE isoform (85%) in the studied population. The percentile of normotensive subjects with three isoforms was 62%. Our findings could contribute to the development of new efficient strategy to prevent and treat hypertension to avoid the development of cardiovascular disease.

Low-dose enalapril reduces angiotensin II and attenuates diabetic-induced cardiac and autonomic dysfunctions.

Abstract Activation of renin–angiotensin system has been linked to cardiovascular and autonomic dysfunctions in diabetes. Experiments were performed to investigate the effects of angiotensin-converting enzyme inhibitor (ACEI), enalapril, on cardiac and autonomic functions in diabetic rats. Diabetes was induced by streptozotocin (50 mg/kg), and rats were treated with enalapril (1 mg·kg−1·d−1). After 30 days, evaluations were performed in control, diabetic, and enalapril-treated groups. Cardiac function was evaluated by echocardiography and through cannulation of the left ventricle (at baseline and in response to volume overload). Heart rate and systolic blood pressure variabilities were evaluated in the time and frequency domains. Streptozotocin rats had left ventricular systolic and diastolic dysfunctions, expressed by reduced ejection fraction and increased isovolumic relaxation time. The ACEI prevented these changes, improved diastolic cardiac responses to volume overload and total power of heart rate variability, reduced the ACE1 activity and protein expression and cardiac angiotensin (Ang) II levels, and increased angiotensin-converting enzyme 2 activity, despite unchanged blood pressure. Correlations were obtained between Ang II content with systolic and diastolic functions and heart rate variability. These findings provide evidence that the low-dose ACEI prevents autonomic and cardiac dysfunctions induced by diabetes without changing blood pressure and associated with reduced cardiac Ang II and increased angiotensin-converting enzyme 2 activity.

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-β (transforming growth factor β), 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-β 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-β 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.

Overexpression of Urinary N-Domain ACE in Chronic Kidney Dysfunction in Wistar Rats

Local activation of the renin–angiotensin system (RAS) has been implicated in the pathogenesis of several renal disorders. In this study we investigated how chronic kidney disease (CKD) modulates RAS components in an experimental model. Male Wistar rats were divided into three groups: sham, nephrectomized, and nephrectomized receiving losartan. Chronic kidney disease animals presented decreased renal N-domain angiotensin-converting enzyme (ACE) activity but overexpression of N-domain ACE in urine. Remnant kidneys presented high angiotensin II levels. Losartan treatment increased urine and tissue ACE activity and tissue levels of angiotensins, mainly angiotensin (1–7), and improved renal and histopathologic parameters. Taken together, the authors’ results indicate that pathophysiological changes due to CKD could lead to an increased expression of somatic and N-domain ACE, mainly the 65 kDa isoform, suggesting that this enzyme could be used as a biological urinary marker in CKD.

Association of Urinary N-Domain Angiotensin I-Converting Enzyme with Plasma Inflammatory Markers and Endothelial Function

The aim of this study was to investigate the association between urinary 90 kDa N-domain Angiotensin I-converting enzyme (ACE) form with C-reactive protein (CRP) and homocysteine plasma levels (Hcy), urinary nitric oxide (NOu), and endothelial function (EF) in normotensive subjects. Forty healthy subjects were evaluated through brachial Doppler US to test the response to reactive hyperemia and a panel of blood tests to determine CRP and Hcy levels, NOu, and urinary ACE. They were divided into groups according to the presence (ACE90+) or absence (ACE90−) of the 90 kDa ACE, the presence (FH+) or absence (FH−) of family history of hypertension, and the presence or absence of these two variables FH+/ACE90+ and FH−/ACE90−. We found an impaired endothelial dilatation in subjects who presented the 90 kDa N-domain ACE as follows: 11.4% ± 5.3% in ACE90+ compared with 17.6% ± 7.1% in ACE90− group and 12.4% ± 5.6% in FH+/ACE90+ compared with 17.7% ± 6.2% in FH−/ACE90− group, P < 0.05. Hcy and CRP levels were statistically significantly lower in FH+/ACE90+ than in FH−/ACE90− group, as follows: 10.0 ± 2.3 µM compared with 12.7 ± 1.5 µM, and 1.3 ± 1.8 mg/L compared with 3.6 ± 2.0 mg/L, respectively. A correlation between flow-mediated dilatation (FMD) and CRP, Hcy, and NOu levels was not found. Our study suggests a reduction in the basal NO production confirmed by NOu analysis in subjects with the 90 kDa N-domain ACE isoform alone or associated with a family history of hypertension. Our data suggest that the presence of the 90 kDa N-domain ACE itself may have a negative impact on flow-mediated dilatation stimulated by reactive hyperemia.

Angiotensin Converting Enzyme 90 kDa isoform: Biomarker for diagnosis of preeclampsia?☆

Preeclampsia (PE), one of the leading gestational hypertensive diseases, is characterized by increased blood pressure (⩾140/90mmHg) and pathological proteinuria after 20weeks gestation. It is a complex, multifactorial syndrome with an unestablished etiology and cure. The search continues for a biomarker that could assist in the early prediction or diagnosis of PE, reducing the rate of maternal and fetal mortality. Based on the findings of Casarini et al. that suggest the 90kDa isoform of the Angiotensin Converting Enzyme (ACE) as a possible marker of hypertension, we hypothesized that this isoform may be present in pregnant women with PE, since they present a transient and spontaneous model of systemic arterial hypertension in pregnancy. We believe, therefore, that pregnant women with pure PE (PPE) express the ACE 90kDa isoform in urine, as well as having elevated isoform enzymatic activity, during pregnancy only. Postpartum, with the normalization of blood pressure, the protein isoform would no longer be expressed. Pregnant women with superimposed preeclampsia (SPE) would present the ACE 90kDa isoform both during and after the gestation period, and its enzymatic activity would remain high as they are chronically hypertensive. It is expected that normotensive pregnant women do not present this isoform in their urine as elevated blood pressure levels do not occur. Both normotensive and PPE affected pregnant women with a family history of hypertension, will possibly express the ACE 90kDa isoform before pregnancy and may become hypertensive, only after some years, through the influence of environmental factors and/or other diseases. If our hypothesis is confirmed, it will allow differentiation of PPE and SPE sooner than 12weeks postpartum, which is currently the estimated period for confirmation of the specific diagnosis. Furthermore, it could be an early biomarker for predicting the disease, enabling the physician to choose the best clinical management. In addition, it would minimize the use of other methods as the biological sample for obtaining the marker is urine, a practical and effective test with good reproducibility. Finally, test results would enable a greater understanding of the mechanisms involved in gestational hypertension.