Publications by authors named "I C Moraes-Silva"

30 Publications

Acute ingestion of a high-fructose drink impairs vascular autonomic modulation and reflex control of blood pressure in first-degree relatives of diabetic patients.

Diabetes Res Clin Pract 2021 May 2:108793. Epub 2021 May 2.

Cardiology Institute (IC)/Cardiology University Foundation (FUC) of Rio Grande do Sul, Porto Alegre, Brazil; Physical Therapy Department, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, Brazil.

First-degree relatives of diabetes patients, despite being euglycemic, presented impaired BRS and exacerbation of sympathetic modulation after ingestion of a high fructose drink when challenged to orthostatic stress. This finding alerts the importance of early autonomic dysfunction even in clinically healthy people, especially in face of a stressful situation.
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http://dx.doi.org/10.1016/j.diabres.2021.108793DOI Listing
May 2021

Acute renal denervation normalizes aortic function and decreases blood pressure in spontaneously hypertensive rats.

Sci Rep 2020 12 11;10(1):21826. Epub 2020 Dec 11.

Instituto do Coração da Faculdade de Medicina da Universidade de São Paulo (InCor-FMUSP), São Paulo, Brazil.

Mechanisms involved in the acute responses to renal denervation (RDN) have yet to be fully understood. We assessed urinary volume, autonomic control and aorta vascular reactivity after acute RDN. Male normotensive Wistar rats and spontaneously hypertensive rats (SHR) were divided into normotensive + RDN (ND) or sham surgery (NS), and hypertensive + RDN (HD) or sham surgery (HS). Metabolic parameters and hemodynamic measurements were recorded 72h and 4 days after intervention, respectively. Aortic rings were studied 7 days post RDN in an isometric myograph. Concentration-response curves to phenylephrine, sodium nitroprusside and acetylcholine (10-10 M) were performed. Two-way ANOVA was used for group comparisons and differences reported when p < 0.05. Results are presented as mean ± SEM. Urinary volume was 112% higher in HD vs. HS (HS = 14.94 ± 2.5 mL; HD = 31.69 ± 2.2 mL) and remained unchanged in normotensive rats. Systolic BP was lower in HD rats (HS = 201 ± 12 vs. HD = 172 ± 3 mmHg) without changes in normotensive group. HD group showed increased HF and LF modulation (HS = 5.8 ± 0.7 ms vs. HD = 13.4 ± 1.4 ms; HS = 3.5 ± 0.7 ms vs. HD = 10.5 ± 1.7 ms, respectively). RDN normalized vascular reactivity in HD rats and increased phenylephrine response in ND rats. Acute fall in BP induced by RDN is associated with increased urinary volume, which in turn may also have contributed to functional changes of the aorta.
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http://dx.doi.org/10.1038/s41598-020-78674-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7733454PMC
December 2020

Exercise training initiated at old stage of lifespan attenuates aging-and ovariectomy-induced cardiac and renal oxidative stress: Role of baroreflex.

Exp Gerontol 2019 09 11;124:110635. Epub 2019 Jun 11.

Laboratory of Translational Physiology, Universidade Nove de Julho (UNINOVE), São Paulo, Brazil; Department of Physiology, Federal University of São Paulo, São Paulo, Brazil. Electronic address:

Background: The association of aging and menopause is a potent risk factor for cardiometabolic disease. We studied the impact of aerobic exercise training (ET) initiated in the old stage of lifespan in hemodynamics, metabolic, autonomic and oxidative stress.

Methods: Aged (18 months old) female Wistar rats were divided into: ovariectomized and untrained (AG-OVX), and ovariectomized and trained (AG-OVXt, ET for 8 weeks). Intact aged (AG) and young female rats (3 months old; Y) were also studied. Blood pressure and metabolic parameters were measured. Baroreflex sensitivity (BRS) was studied by bradycardic (BR) and tachycardic (TR) responses to vasoactive drugs. Cardiac and renal lipid peroxidation (LPO), catalase (CAT), superoxide dismutase (SOD) and gluthatione peroxidase (GPx), and gluthatione redox balance (GSH/GSSG) were analyzed.

Results: AG-OVXt group increased aerobic performance in 35%, decreased adipose tissue and triglycerides in 36% and 27%, respectively, and improved insulin tolerance in 50% in comparison to AG-OVX. AG-OVX presented hypertensive levels of blood pressure (systolic: 155 ± 5, diastolic: 111 ± 3 mmHg). In contrast, AG-OVXt presented blood pressure values similar to Y rats (systolic: 129 ± 3, diastolic: 112 ± 3 mmHg). TR and BR were reduced by 70% and 46%, respectively, in AG-OVX vs. Y. Once more, AG-OVXt presented similar results to Y. ET decreased LPO in the heart and kidney. In the latter, renal CAT and SOD were corrected by ET, while cardiac redox balance was partially recovered. Improved BRS was correlated with improved oxidative stress markers.

Conclusions: Even when initiated after aging and ovariectomy deleterious effects, ET is able to normalize BRS and highly improve cardiac and renal oxidative stress.
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http://dx.doi.org/10.1016/j.exger.2019.110635DOI Listing
September 2019

The role of the baroreflex and parasympathetic nervous system in fructose-induced cardiac and metabolic alterations.

Sci Rep 2018 Jul 20;8(1):10970. Epub 2018 Jul 20.

Heart Institute (InCor), School of Medicine, University of Sao Paulo (FMUSP), Sao Paulo, Brazil.

It is well-established that baroreflex sensitivity is essential for blood pressure control, and also plays a key role in the modulation of disease-induced metabolic alterations. In order to investigate the role of the baroreflex in the cardiometabolic and inflammatory derangements promoted by fructose overload, Wistar rats underwent sinoaortic denervation (SAD) or sham surgery and were studied 90 days after receiving tap water (Den and Ctrl) or a 10% fructose solution (Fruc and Den-Fruc). All experimental groups showed marked and similar degree of baroreflex impairment compared to Ctrl. As expected, fructose overload effectively induced metabolic syndrome; however, when it was associated with SAD, several alterations were attenuated. While Fruc rats displayed increased sympathetic modulation and tone and reduced vagal modulation compared to Ctrl animals, Den-Fruc rats showed greater vagal tone and modulation when compared to the Fruc group. Moreover, the Den-Fruc group showed augmented expression of β1 adrenergic receptors and TNF/IL-10 ratio and reduction of β2 in the left ventricle. The increase in vagal function was correlated with improved insulin sensitivity (r = 0.76), and decreased abdominal fat (r = -0.78) and β2 receptors (r = -0.85). Our results showed that: (1) chronic fructose overload induced severe baroreflex impairment, i.e. in a similar magnitude to that observed in SAD rats, which is accompanied by cardiometabolic dysfunctions; (2) the compensatory enhancement in parasympathetic function in SAD rats submitted to fructose intake may point out the possibility of use of approaches that improve vagal function as therapeutic target to attenuate fructose-induced cardiometabolic dysfunctions.
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http://dx.doi.org/10.1038/s41598-018-29336-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6054615PMC
July 2018