A High-Fat Diet Induces Cardiac Damage in Obesity-Resistant Rodents with Reduction in Metabolic Health.

BACKGROUND/AIMS: Obesity resistance is associated with the complex interaction of stringent and environmental factors that confer the ability to resist mass gain and body fat deposition, even when eating high-calorie diets. Considering that there are numerous gaps in the literature on the metabolic processes that explain Obesity resistance, specifically in relation to oxidative stress, the purpose of the study was to investigate whether obesity-resistant (OR) rats develop elevated reactive oxygen species in cardiac tissue. METHODS: Wistar rats were initially randomized into two groups: a standard diet (SD) and a high-fat diet (HFD) group. The SD and HFD groups were further divided into control (C), OR, and obese prone (OP) subgroups based on body weight. This criterion consisted of organizing the animals in each group in ascending order according to body weight (BW), and the cutoff point was identified in the animals by terciles: 1) lower BW; 2) intermediate BW; and 3) higher BW. Rats were sacrificed on the 14th week, and serum and organs were collected. Nutritional assessment, food profiles, histological analysis, comorbidities, and cardiovascular characteristics were determined. RESULTS: BW showed a significant difference between the standard diet and high-fat diet groups in the 4th week of the experimental protocol, characterizing obesity. In the 4th week, after the characterization of Obesity resistance, there was a significant difference in BW between groups C, OP, and OR. The OP and OR groups showed a significant increase in caloric intake in relation to the C group. The OP group showed a significant increase in final BW, retroperitoneal fat pad mass, sum of corporal fat deposits and reactive oxygen species, in relation to groups C and OR. The area under the glycemic curve, insulin resistance index and basal glucose were elevated in the OP group in relation to the C. OP also promoted an increase in HOMA-IR when compared with C. OR rats showed a non-significant increase in insulin and HOMA-IR in OR vs. C (p = ~0.1), but no significant differences were observed between OP vs. OR for these parameters, suggesting that both groups suffered from decreased metabolic health. Total cardiac mass, left ventricular cross-sectional area, and cholesterol levels were significantly elevated in the OP and OR groups compared with the C group. CONCLUSION: A high-fat diet induces cardiac damage in obesity-resistant rodents with reduction in metabolic health.

Cardiovascular Harmful Effects of Recommended Daily Doses (13 µg/kg/day), Tolerable Upper Intake Doses (0.14 mg/kg/day) and Twice the Tolerable Doses (0.28 mg/kg/day) of Copper.

Copper is essential for homeostasis and regulation of body functions, but in excess, it is a cardiovascular risk factor since it increases oxidative stress. The objective of this study was to evaluate the effects of exposure to the recommended daily dose (13 µg/kg/day), upper tolerable dose (0.14 mg/kg/day) and twice the upper tolerable dose (0.28 mg/kg/day) via i.p. over 4 weeks on the vascular reactivity of aortic rings and the contraction of LV papillary muscles of male Wistar rats. It was also determined whether the antioxidant peptide from egg white hydrolysate (EWH) prevents these effects. Copper exposure at the doses evaluated did not change weight gain of male Wistar rats, the reactivity of the aortic rings or the cardiac mass. The dose of 0.13 µg/kg/day did not reduce the force of contraction, but it impaired the time derivatives of force. Doses of 0.14 and 0.28 mg/kg/day reduced the force of contraction, the inotropic response to calcium and isoproterenol, the postrest contraction and the peak and plateau of tetanized contractions. EWH treatment antagonized these effects. These results suggest that copper, even at the dose described as upper tolerable, can impair cardiac contraction without altering vascular reactivity. Antioxidative stress therapy with EWH reversed these harmful effects, suggesting a possible strategy for the amelioration of these effects.

Copper exposure for 30 days at a daily dose twice the recommended increases blood pressure and cardiac contractility.

Copper is an essential factor for the body's homeostasis. However, excess copper compromises organic functions. AIMS: We investigated the effects of copper exposure for 30 days on blood pressure (BP) and cardiac contractility and the putative involvement of nitric oxide (NO) and reactive oxygen species. MAIN METHODS: Wistar rats (12 weeks old, 280 g) were randomized to the treated group that was exposed for 30 days to copper (2000 µg/kg/day CuCl2) and the control (Ct) group that received intraperitoneal saline (0.9%). KEY FINDINGS: The blood concentration of copper was ~1.26 µg/mL in the copper-exposed group and ~0.024 µg/mL in the Ct group. The main metal accumulations occurred in the liver and kidneys. Copper exposure increased systolic BP (Cu: 141 ± 3 mmHg; Ct: 133 ± 3 mmHg) (tail cuff method), left ventricular systolic pressure and papillary muscle force. Calcium release from the sarcoplasmic reticulum was reduced. The contractile response to Ca2+ was increased by copper, and the effect was not altered by L-NAME. Copper increased contractions dependent on sarcolemmal Ca2+ influx, and this effect was not altered by L-NAME. The percentage response to isoproterenol decreased in the copper-exposed group, but L-NAME did not alter this reduction. Papillary force development at the peak and plateau of tetanic contractions also increased after copper exposure, but this effect was not altered by L-NAME. In situ detection of OH local production increased. SIGNIFICANCE: Copper increased BP and cardiac force, increased Ca2+ inflow, reduced Ca2+ reuptake by the sarcoplasmic reticulum, and increased OH local production. Copper exposure at doses considered tolerable affects cardiac contractility.

Mercury induces nuclear estrogen receptors to act as vasoconstrictors promoting endothelial denudation via the PI3K/Akt signaling pathway.

Cardiovascular diseases (CVD) are more frequent among postmenopausal women due to the decline of estrogen concentration in plasma. However, the role of the vascular modulator effect of estrogen is controversial, since it occurs both in physiological and pathological conditions, increasing or reducing vascular reactivity. As mercury is widely associated with the development of CVD, we investigated putative hazardous effects on the mechanisms that modulate vascular reactivity in aortic rings of female Wistar rats promoted by acute mercury exposure. Mercury increased vascular reactivity and oxidative stress possibly due to NADPH oxidase participation, increased production of cyclooxygenase-2 (COX-2) and thromboxane A2 (TXA2) formation. The metal also induced endothelial denudation in the aorta by reducing the bioavailability of nitric oxide (NO) and enhancing the activity of the PI3K/Akt signaling pathway. Mercury exposure also induced nuclear estrogen receptors (ERα, ERß) to act as vasoconstrictors. Our findings suggest that mercury might increase the chances of developing cardiovascular diseases in females and should be considered an important environmental risk factor.

Uso de tecnologias no ensino de semiologia e semiotécnica de enfermagem / Uso de la tecnología en la enseñanza de semiología y semiotécnica de enfermería / Use of technology in the teaching of nursing semiology and semiotechnique

Objetivo relatar a vivência de discentes, docentes e monitores na utilização de diferentes tecnologias educativas durante ensino teórico-prático de semiologia e semiotécnica de enfermagem. Método relato de prática de ensino de 2 monitores, 2 docentes e 187 alunos de um curso de graduação em enfermagem de Vitória, Espírito Santo, realizado de 2015 a 2017, com reflexões sustentadas no referencial teórico de Merhy. Resultados o ensino foi mediado por tecnologias leves associadas às leve-duras e duras, buscando-se o desenvolvimento de competências que pudessem aprimorar a produção de conhecimentos e que possam futuramente ser aplicadas na prática profissional, tendo como horizonte um cuidado de enfermagem humanizado e não restrito ao tecnicismo. Conclusão a práxis pedagógica relatada favoreceu ao desenvolvimento de competências relacionais e manuais, à autonomia discente e ao pensamento crítico-reflexivo, necessários à articulação teórico-prática, à tomada de decisão clínica e a novos modos de se produzir cuidado em enfermagem.

Objetivo reportar la experiencia de los estudiantes, profesores y monitores en el uso de diferentes tecnologías educativas durante la enseñanza teórica-práctica de semiología y semiotécnica de enfermería. Método relato de práctica docente de 2 monitores, 2 profesores y 187 estudiantes de un curso de graduación en enfermería de Vitória, Espírito Santo, realizado de 2015 a 2017, con reflexiones sostenidas sobre el referencial teórico de Merhy. Resultados la enseñanza era mediada por tecnologías leves, asociadas a leves-duras, buscando el desarrollo de habilidades que podrían mejorar la producción de conocimiento, y que, en el futuro, podrían ser aplicadas en la práctica profesional, teniendo como horizonte un cuidado de enfermería humanizado y no restringido al tecnicismo. Conclusión lapraxis pedagógica relatada favoreció el desarrollo de competencias relacionales y manuales, la autonomía de los estudiantes y el pensamiento crítico y reflexivo, necesarios para la vinculación teórico-práctica, la toma de decisiones clínicas y las nuevas formas de producción de los cuidados de enfermería.

Objective to report the experience of students, professors and professor's assistants (PA) when using different educational technologies during theoretical-practical teaching of nursing semiology and semiotechnique. Method report of teaching practice of 2 PA, 2 professors and 187 students from a Nursing graduate course in Vitória, Espírito Santo, conducted from 2015 to 2017, with reflections based on Merhy's theory. Results the teaching was mediated by soft technologies associated to soft-hard ones, seeking the development of skills that could enhance knowledge production, and, in the future, be applied in professional practice, having as horizon a humanized nursing care, not restricted to techniques. Conclusion the reported pedagogical praxis favored the development of relational and manual competences, the student's autonomy and critical and reflective thinking, necessary the theoretical-practical articulation, clinical decision-making and new ways of producing nursing care.

Reactive oxygen species impair the excitation-contraction coupling of papillary muscles after acute exposure to a high copper concentration.

Copper is an essential metal for homeostasis and the functioning of living organisms. We investigated the effects of a high copper concentration on the myocardial mechanics, investigating the reactive oxygen species (ROS) mediated effects. The developed force of papillary muscles was reduced after acute exposure to a high copper concentration and was prevented by co-incubation with tempol, DMSO and catalase. The reuptake of calcium by the sarcoplasmic reticulum was reduced by copper and restored by tempol. The contractile response to Ca2+ was reduced and reversed by antioxidants. The response to the ß-adrenergic agonist decreased after exposure to copper and was restored by tempol and catalase. In addition, the in situ detection showed increased O2·- and OH·. Contractions dependent on the sarcolemmal Ca2+ influx were impaired by copper and restored by antioxidants. Myosin-ATPase activity decreased significantly after copper exposure. In conclusion, a high copper concentration can acutely impair myocardial excitation-contraction coupling, reduce the capacity to generate force, reduce the Ca2+ inflow and its reuptake, and reduce myosin-ATPase activity, and these effects are mediated by the local production of O2·-, OH· and H2O2. These toxicity effects of copper overload suggest that copper is a risk factor for cardiovascular disease.