Iris Callado Sanches

Bio: Iris Callado Sanches is an academic researcher from Universidade São Judas Tadeu. The author has contributed to research in topics: Blood pressure & Heart rate. The author has an hindex of 14, co-authored 37 publications receiving 437 citations. Previous affiliations of Iris Callado Sanches include University of São Paulo.

Parasympathetic dysfunction is associated with insulin resistance in fructose-fed female rats

Abstract: The objective of the present study was to identify metabolic, cardiovascular and autonomic changes induced by fructose overload administered in the drinking water of rats for 8 weeks. Female Wistar rats (200-220 g) were divided into 2 groups: control (N = 8) and fructose-fed rats (N = 5; 100 mg/L fructose in drinking water for 8 weeks). The autonomic control of heart rate was evaluated by pharmacological blockade using atropine (3 mg/kg) and propranolol (4 mg/kg). The animals were submitted to an intravenous insulin tolerance test (ITT) and to blood glucose measurement. The fructose overload induced a significant increase in body weight (approximately 10%) and in fasting glycemia (approximately 28%). The rate constant of glucose disappearance (KITT) during ITT was lower in fructose-fed rats (3.25 +/- 0.7%/min) compared with controls (4.95 +/- 0.3%/min, P < 0.05) indicating insulin resistance. The fructose-fed group presented increased arterial pressure compared to controls (122 +/- 3 vs 108 +/- 1 mmHg, P < 0.05) and a reduction in vagal tonus (31 +/- 9 vs 55 +/- 5 bpm in controls, P < 0.05). No changes in sympathetic tonus were observed. A positive correlation, tested by the Pearson correlation, was demonstrable between cardiac vagal tonus and KITT (r = 0.8, P = 0.02). These data provided new information regarding the role of parasympathetic dysfunction associated with insulin resistance in the development of early metabolic and cardiovascular alterations induced by a high fructose diet.

Standardization of resistance exercise training: effects in diabetic ovariectomized rats.

Abstract: This study was carried out with a 3-fold aim: 1) to standardize a maximal load test (MLT) on ladders for prescription of resistance exercise training (RET) in rats, 2) to prescribe moderate-intensity RET based on this MLT and 3) to test the effect of this RET in diabetic ovariectomized rats. Female Wistar rats were divided into control (C), diabetic ovariectomized sedentary (DOS) and trained (DOT) groups. The MLT was standardized with increased load applied to the rat tail for each climb, and blood lactate was measured to identify lactate threshold in C rats. MLT was applied in the 1st, 4th and 8th week of the protocol. After 8 weeks of RET, the arterial pressure was directly recorded. DOS group reduced performance in MLT, body weight, left ventricular, plantar and soleus muscles mass (vs. C). DOT rats showed an improvement in MLT associated with plantar muscle mass increased (vs. C and DOS), with attenuation of hypotension and bradycardia (vs. DOS). In conclusion, the results provide a useful method for determining the maximal load and applying RET in rats. Moreover, this study showed that moderate intensity RET improves hemodynamic status in diabetic ovariectomized rats, thereby reinforcing the role of RET in diabetes management.

Cardiometabolic benefits of exercise training in an experimental model of metabolic syndrome and menopause.

Abstract: ObjectiveThe aim of this study was to investigate the cardiometabolic effects of exercise training in ovariectomized hypertensive rats both submitted and not submitted to fructose overload.MethodsSpontaneously hypertensive ovariectomized rats were divided into sedentary and trained (THO) gro

Increased Fructose Associates with Elevated Blood Pressure

Abstract: The recent increase in fructose consumption in industrialized nations mirrors the rise in the prevalence of hypertension, but epidemiologic studies have inconsistently linked these observations. We investigated whether increased fructose intake from added sugars associates with an increased risk for higher BP levels in US adults without a history of hypertension. We conducted a cross-sectional analysis using the data collected from the National Health and Nutrition Examination Survey (NHANES 2003 to 2006) involving 4528 adults without a history of hypertension. Median fructose intake was 74 g/d, corresponding to 2.5 sugary soft drinks each day. After adjustment for demographics; comorbidities; physical activity; total kilocalorie intake; and dietary confounders such as total carbohydrate, alcohol, salt, and vitamin C intake, an increased fructose intake of ≥74 g/d independently and significantly associated with higher odds of elevated BP levels: It led to a 26, 30, and 77% higher risk for BP cutoffs of ≥135/85, ≥140/90, and ≥160/100 mmHg, respectively. These results suggest that high fructose intake, in the form of added sugar, independently associates with higher BP levels among US adults without a history of hypertension.

Dietary Glycemic Load and Cancer Recurrence and Survival in Patients with Stage III Colon Cancer: Findings From CALGB 89803

Abstract: Preclinical and clinical evidence indicates that hyperinsulinemia may play an important role in the development of colorectal cancer (1,2). Many of the established risk factors of colorectal cancer, including obesity (3,4) and physical inactivity (5), directly influence insulin levels. Other studies have observed elevated risks of colon cancer among those with a history of type 2 diabetes mellitus (6) or elevated blood insulin or plasma C-peptide levels (7–10). Diet influences systemic insulin levels. Foods with low glucose indexes have reduced serum insulin and glucose responses, compared with foods with high indexes. The physiological response to carbohydrates can be quantified by the glycemic index, a qualitative assessment of foods calculated as a percentage of the body’s plasma glucose response to specific foods compared with the response induced by the same amount of carbohydrate from a standard carbohydrate source, usually white bread or pure glucose (11,12). The glycemic load is calculated by multiplying the carbohydrate index of each food by its glycemic index and the frequency of consumption, providing a qualitative and quantitative measurement (13). Glycemic load and other carbohydrate measures have been associated with the risk of developing colorectal cancer in some (14–17), but not all (18–21), studies. Recent studies have found a direct association between host factors leading to hyperinsulemia and cancer recurrences and mortality in colorectal cancer survivors (22–28). In a study of stage III colon cancer patients, the highest quintile of consumption of a Western pattern diet (characterized by high intakes of meat, fat, refined grains, and sugar desserts) was associated with a three-fold increase in cancer recurrence and deaths compared with the lowest quintile (27). To further understand which component of a Western pattern diet is associated with poorer outcomes and define the impact of dietary glycemic measures on colon cancer survival, we prospectively examined the association between dietary glycemic load and index, total fructose intake, and total carbohydrates intake on cancer recurrences and survival in a cohort of stage III colon cancer patients enrolled in an adjuvant chemotherapy trial in which extensive data on dietary intake, height, weight, and physical activity were collected at the study onset prior to any subsequent events of cancer recurrence.

Isocaloric fructose restriction and metabolic improvement in children with obesity and metabolic syndrome

Abstract: Objective: Dietary fructose is implicated in metabolic syndrome, but intervention studies are confounded by positive caloric balance, changes in adiposity, or artifactually high amounts. This study determined whether isocaloric substitution of starch for sugar would improve metabolic parameters in Latino (n 527) and African-American (n 516) children with obesity and metabolic syndrome. Methods: Participants consumed a diet for 9 days to deliver comparable percentages of protein, fat, and carbohydrate as their self-reported diet; however, dietary sugar was reduced from 28% to 10% and substituted with starch. Participants recorded daily weights, with calories adjusted for weight maintenance. Participants underwent dual-energy X-ray absorptiometry and oral glucose tolerance testing on Days 0 and 10. Biochemical analyses were controlled for weight change by repeated measures ANCOVA. Results: Reductions in diastolic blood pressure (25 mmHg; P 50.002), lactate (20.3 mmol/L; P <0.001), triglyceride, and LDL-cholesterol (246% and 20.3 mmol/L; P <0.001) were noted. Glucose tolerance and hyperinsulinemia improved (P <0.001). Weight reduced by 0.9 60.2 kg (P <0.001) and fat-free mass by 0.6 kg (P 50.04). Post hoc sensitivity analysis demonstrates that results in the subcohort that did not lose weight (n 510) were directionally consistent. Conclusions: Isocaloric fructose restriction improved surrogate metabolic parameters in children with obesity and metabolic syndrome irrespective of weight change.

The crosstalk between autonomic nervous system and blood vessels

Abstract: The autonomic nervous system (ANS), comprised of two primary branches, sympathetic and parasympathetic nervous system, plays an essential role in the regulation of vascular wall contractility and tension. The sympathetic and parasympathetic nerves work together to balance the functions of autonomic effector organs. The neurotransmitters released from the varicosities in the ANS can regulate the vascular tone. Norepinephrine (NE), adenosine triphosphate (ATP) and Neuropeptide Y (NPY) function as vasoconstrictors, whereas acetylcholine (Ach) and calcitonin gene-related peptide (CGRP) can mediate vasodilation. On the other hand, vascular factors, such as endothelium-derived relaxing factor nitric oxide (NO), and constriction factor endothelin, play an important role in the autonomic nervous system in physiologic conditions. Endothelial dysfunction and inflammation are associated with the sympathetic nerve activity in the pathological conditions, such as hypertension, heart failure, and diabetes mellitus. The dysfunction of the autonomic nervous system could be a risk factor for vascular diseases and the overactive sympathetic nerve is detrimental to the blood vessel. In this review, we summarize findings concerning the crosstalk between ANS and blood vessels in both physiological and pathological conditions and hope to provide insight into the development of therapeutic interventions of vascular diseases.