Patricia Fiorino

Systemic delivery of adult stem cells improves cardiac function in spontaneously hypertensive rats

1 Heart regeneration after myocardial infarction (MI) can occur after cell therapy, but the mechanisms, cell types and delivery methods responsible for this improvement are still under investigation. In the present study, we evaluated the impact of systemic delivery of bone marrow cells (BMC) and cultivated mesenchymal stem cells (MSC) on cardiac morphology, function and mortality in spontaneously hypertensive rats (SHR) submitted to coronary occlusion. 2 Female syngeneic adult SHR, submitted or not (control group; C) to MI, were treated with intravenous injection of MSC (MI + MSC) or BMC (MI + BM) from male rats and evaluated after 1, 15 and 30 days by echocardiography. Systolic blood pressure (SBP), functional capacity, histology, mortality rate and polymerase chain reaction for the Y chromosome were also analysed. 3 Myocardial infarction induced a decrease in SBP and BMC, but not MSC, prevented this decrease. An improvement in functional capacity and ejection fraction (38 ± 4, 39 ± 3 and 58 ± 2% for MI, MI + MSC and MI + BM, respectively; P < 0.05), as well as a reduction of the left ventricle infarcted area, were observed in rats from the MI + BM group compared with the other three groups. Treated animals had a significantly reduced lesion tissue score. The mortality rate in the C, MI + BM, MI + MSC and MI groups was 0, 0, 16.7 and 44.4%, respectively (P < 0.05 for the MI + MSC and MI groups compared with the C and MI + BM groups). 4 The results of the present study suggest that systemic administration of BMC can improve left ventricular function, functional capacity and, consequently, reduce mortality in an animal model of MI associated with hypertension. We speculate that the cells transiently home to the myocardium, releasing paracrine factors that recruit host cells to repair the lesion.

Exercise Training Prevents Cardiovascular Derangements Induced by Fructose Overload in Developing Rats

The risks of chronic diseases associated with the increasing consumption of fructose-laden foods are amplified by the lack of regular physical activity and have become a serious public health issue worldwide. Moreover, childhood eating habits are strongly related to metabolic syndrome in adults. Thus, we aimed to investigate the preventive role of exercise training undertaken concurrently with a high fructose diet on cardiac function, hemodynamics, cardiovascular autonomic modulation and oxidative stress in male rats after weaning. Male Wistar rats were divided into 4 groups (n = 8/group): Sedentary control (SC), Trained control (TC), Sedentary Fructose (SF) and Trained Fructose (TF). Training was performed on a treadmill (8 weeks, 40–60% of maximum exercise test). Evaluations of cardiac function, hemodynamics, cardiovascular autonomic modulation and oxidative stress in plasma and in left ventricle (LV) were performed. Chronic fructose overload induced glucose intolerance and an increase in white adipose tissue (WAT) weight, in myocardial performance index (MPI) (SF:0.42±0.04 vs. SC:0.24±0.05) and in arterial pressure (SF:122±3 vs. SC:113±1 mmHg) associated with increased cardiac and vascular sympathetic modulation. Fructose also induced unfavorable changes in oxidative stress profile (plasmatic protein oxidation- SF:3.30±0.09 vs. SC:1.45±0.08 nmol/mg prot; and LV total antioxidant capacity (TRAP)- SF: 2.5±0.5 vs. SC:12.7±1.7 uM trolox). The TF group showed reduced WAT, glucose intolerance, MPI (0.35±0.04), arterial pressure (118±2mmHg), sympathetic modulation, plasmatic protein oxidation and increased TRAP when compared to SF group. Therefore, our findings indicate that cardiometabolic dysfunctions induced by fructose overload early in life may be prevented by moderate aerobic exercise training.

Effect of High-Fat Diet upon Inflammatory Markers and Aortic Stiffening in Mice

Changes in lifestyle such as increase in high-fat food consumption are an important cause for vascular diseases. The present study aimed to investigate the involvement of ACE and TGF-β in the aorta stiffness induced by high-fat diet. C57BL/6 male mice were divided in two groups according to their diet for 8 weeks: standard diet (ST) and high-fat diet (HF). At the end of the protocol, body weight gain, adipose tissue content, serum lipids and glucose levels, and aorta morphometric and biochemical measurements were performed. Analysis of collagen fibers by picrosirius staining of aorta slices showed that HF diet promoted increase of thin (55%) and thick (100%) collagen fibers deposition and concomitant disorganization of these fibers orientations in the aorta vascular wall (50%). To unravel the mechanism involved, myeloperoxidase (MPO) and angiotensin I converting enzyme (ACE) were evaluated by protein expression and enzyme activity. HF diet increased MPO (90%) and ACE (28%) activities, as well as protein expression of ACE. TGF-β was also increased in aorta tissue of HF diet mice after 8 weeks. Altogether, we have observed that the HF diet-induced aortic stiffening may be associated with increased oxidative stress damage and activation of the RAS in vascular tissue.

Bases moleculares da glomerulopatia diabética

The determinant of the diabetic nephropathy is hyperglycemia, but hypertension and other genetic factors are also involved. Glomerulus is the focus of the injury, where mesangial cell proliferation and extracellular matrix occur because of the increase of the intra- and extracellular glucose concentration and overexpression of GLUT1. Sequentially, there are increases in the flow by the poliol pathway, oxidative stress, increased intracellular production of advanced glycation end products (AGEs), activation of the PKC pathway, increase of the activity of the hexosamine pathway, and activation of TGF-b1. High glucose concentrations also increase angiotensin II (AII) levels. Therefore, glucose and AII exert similar effects in inducing extracellular matrix formation in the mesangial cells, using similar transductional signal, which increases TGF-b1 levels. In this review we focus in the effect of glucose and AII in the mesangial cells in causing the events related to the genesis of diabetic nephropathy. The alterations in the signal pathways discussed in this review give support to the observational studies and clinical assays, where metabolic and antihypertensive controls obtained with angiotensin-converting inhibitors have shown important and additive effect in the prevention of the beginning and progression of diabetic nephropathy. New therapeutic strategies directed to the described intracellular events may give future additional benefits.

Intra-Renal Angiotensin Levels Are Increased in High-Fructose Fed Rats in the Extracorporeal Renal Perfusion Model

Overconsumption of fructose leads to metabolic syndrome as a result of hypertension, insulin resistance, and hyperlipidemia. In this study, the renal function of animals submitted to high fructose intake was analyzed from weaning to adulthood using in vivo and ex vivo methods, being compared with a normal control group. We investigated in ex vivo model of the role of the renin Angiotensin system (RAS) in the kidney. The use of perfused kidney from animals submitted to 8-week fructose treatment showed that high fructose intake caused metabolic and cardiovascular alterations that were consistent with other studies. Moreover, the isolated perfused kidneys obtained from rats under high fructose diet showed a 33% increase in renal perfusion pressure throughout the experimental period due to increased renal vascular resistance and a progressive fall in the glomerular filtration rate, which reached a maximum of 64% decrease. Analysis of RAS peptides in the high fructose group showed a threefold increase in the renal concentrations of angiotensin I (Ang I) and a twofold increase in angiotensin II (Ang II) levels, whereas no change in angiotensin 1-7 (Ang 1-7) was observed when compared with the control animals. We did not detect changes in angiotensin converting enzyme (ACE) activity in renal tissues, but there is a tendency to decrease. These observations suggest that there are alternative ways of producing Ang II in this model. Chymase the enzyme responsible for Ang II formation direct from Ang I was increased in renal tissues in the fructose group, confirming the alternative pathway for the formation of this peptide. Neprilysin (NEP) the Ang 1-7 forming showed a significant decrease in activity in the fructose vs. control group, and a tendency of reduction in ACE2 activity. Thus, these results suggest that the Ang 1-7 vasodilator peptide formation is impaired in this model contributing with the increase of blood pressure. In summary, rats fed high fructose affect renal RAS, which may contribute to several deleterious effects of fructose on the kidneys and consequently an increase in blood pressure.

161 ACUTE EFFECT OF HIGH-FAT DIET ON AUTONOMIC AND METABOLIC FUNCTIONS IN ADULT RATS

Objective: The objective of this study was to evaluate the autonomic and metabolic functions in adult rats subjected to a high-fat diet during 21 days Methods: Adult Male Wistar rats (n = 8/group) were divided in Control Group (CG), commercial rat food, and Hyperlipidic Group (HG), addition of 30% unsalted butter in commercial diet, followed by 21 days. Glucose tolerance test were determinate after intravenous glucose load injection (1.5 g/kg, i.p.). Serum insulin was evaluated by radioimmunoassay. Blood Pressure (BP) and Heart Rate (HR) were directly recorded using a data acquisition system (Windaq, 2 KHz) in conscious and awake rats. Cardiac autonomic activity was evaluated using pharmacological blockade (Atenolol, 8 mg/Kg and Atropine, 4 mg/Kg). Results: At the end of the protocol, body weights and food consumption were similar between the groups. The triglycerides levels was increased in HG (79 ± 5 mg/dL) when compared with CG (40 ± 4 mg/dL). The glucose tolerance was higher in HG (226 ± 12 AUC) when compared to CG (169 ± 16 AUC). Insulin was 26% augmented in HG when compared with CG. There were no differences in BP and HR between the groups. Sympathetic tonus was increased in HG (65 ± 9.2 bpm) compared to CG (37 ± 13 bpm) with no differences in vagal tonus. Intrinsic HR was significantly higher in HG (425 ± 4 bpm) when compared with CG (399 ± 7.2 bpm). Conclusions: In conclusion, our data suggest that acute administration of a high-fat diet was able to promote important metabolic alterations that could be associated with cardiovascular autonomic dysfunction.

196 EFFECTS ON SYMPATHETIC ACTIVITY AND RENIN ANGIOTENSIN SYNTEM IN EXPERIMENTAL METABOLIC SYNDROME MODEL

Introduction: Administration of a diet rich in fructose initiates a series of metabolic events resulting in hypertriglyceridemia, hypertension and glucose intolerance. Objectives: The purpose of this study was to evaluate the role of the renin angiotensin system on cardiovascular function induced by fructose intake during 8 weeks. Desing and Methods: Weaned (21 days old) male Wistar rats (50-60 g) were divided in 2 groups and they were followed for 8 weeks: Control (CG) and Fructose (FG, 10% in drinking water). The participation of the renin-angiotensin system has been evaluated by receptor blockade AT1a with losartan (10 mg/kg iv) and by angiotensin-converting enzyme (ACE) in serum by fluorimetric measurements. Ganglionic blockade (hexamethonium, 20 mg/kg, iv) was used to determine vascular activity of sympathetic nervous system. Arterial pressure (AP) and heart rate (HR) were directly recorded using a data acquisition system (Windaq, 2 KHz) in conscious and awake rats. Results: FG showed an increase of mean AP (120±3.1 mmHg) when compared to CG (98±1.6 mmHg). No changes in heart rate were observed. Blocking with losartan showed an increased depressor response in FG (-18 ± 1.7 mm Hg) compared to the GC (-7 ± 1.5 mmHg) likewise after hexamethonium administration. ACE serum in FG (153±2,7 mU/mL) was higher than CG (103±14,3 mU/mL). Conclusions: In conclusion, these data suggest that metabolic changes induced by frutose-rich diet during life spam in rats are accompanied by hypertension associated with increase of renin angiotensin system and sympathetic overactivity.

729 RENAL AND METABOLIC EVALUATIONS IN RATS WITH METABOLIC SYNDROME INDUCED BY FRUCTOSE

Introduction and objectives: High fructose fed rats has previously been described as an animal model of impaired glucose tolerance. The aim of this study was to evaluate the contribution of overloading of fructose on metabolic and renal function in rats. Design and methods: Male Wistar rats (50–60 g) were divided into control group (CG, n = 6) and Fructose Group (FG, 10% fructose, drinking water, 8 weeks, n = 7). Renal Angiotensin I Converting Enzyme activity (ACE) was evaluated by fluorimetry. Angiotensins Quantification were analyzed by HPLC. The kidney was collected for histological glomerular analysis (5 &mgr;m, Picrosirius Red) to evaluate the collagen deposition at Glomerular Tuft (CGT) and Bowman[Combining Acute Accent]s Capsule (CBC). Blood was collected to biochemical assays (Labtest, BR). Results: There was no difference in Lee Index between groups, however the adiposity was increased in FG (8 ± 0,5 g/kg) when compared with CG (6 ± 1 g/kg). Basal glycemia and Triglycerides were augmented in FG when compared with CG. Renal ANG II was increased in FG (63 ± 8,4 pmol/g) when compared with CG (29 ± 2,5 pmol/g). However, there was no changes in renal ACE activity (CG: 5 ± 0,7 vs 4,6 ± 0,7 mU/mg prot). The CGT was higher (25%) in FG when compared with CG. The CBC was also increased in FG (29%) when compared with CG. Conclusions: In conclusion, our data suggest that fructose is related metabolic alterations associated with an increased renal collagen deposition. Moreover, the elevated renal AngII induced by fructose could be involved in tissue damage and contribute to decrease in renal function.