Angiotensin II Requires Zinc and Downregulation of the Zinc Transporters ZnT3 and ZnT10 to Induce Senescence of Vascular Smooth Muscle Cells

Senescence, a hallmark of mammalian aging, is associated with the onset and progression of cardiovascular disease. Angiotensin II (Ang II) signaling and zinc homeostasis dysfunction are increased with age and are linked to cardiovascular disease, but the relationship among these processes has not been investigated. We used a model of cellular senescence induced by Ang II in vascular smooth muscle cells (VSMCs) to explore the role of zinc in vascular dysfunction. We found that Ang II-induced senescence is a zinc-dependent pathway mediated by the downregulation of the zinc transporters ZnT3 and ZnT10, which work to reduce cytosolic zinc. Zinc mimics Ang II by increasing reactive oxygen species (ROS), activating NADPH oxidase activity and Akt, and by downregulating ZnT3 and ZnT10 and inducing senescence. Zinc increases Ang II-induced senescence, while the zinc chelator TPEN, as well as overexpression of ZnT3 or ZnT10, decreases ROS and prevents senescence. Using HEK293 cells, we found that ZnT10 localizes in recycling endosomes and transports zinc into vesicles to prevent zinc toxicity. Zinc and ZnT3/ZnT10 downregulation induces senescence by decreasing the expression of catalase. Consistently, ZnT3 and ZnT10 downregulation by siRNA increases ROS while downregulation of catalase by siRNA induces senescence. Zinc, siZnT3 and siZnT10 downregulate catalase by a post-transcriptional mechanism mediated by decreased phosphorylation of ERK1/2. These data demonstrate that zinc homeostasis dysfunction by decreased expression of ZnT3 or ZnT10 promotes senescence and that Ang II-induced senescence is a zinc and ROS-dependent process. Our studies suggest that zinc might also affect other ROS-dependent processes induced by Ang II, such as hypertrophy and migration of smooth muscle cells

EFFECTS OF DIURNAL AND NOCTURNAL STRENUOUS EXERCISE ON SERUM MELATONIN LEVELS

ABSTRACT Introduction: There are reports of a possible relationship between melatonin, a hormone secreted by the pineal gland, and exercise. Objective: The present study aims to investigate how diurnal and nocturnal strenuous exercise affects melatonin levels. Methods: The study enrolled 10 healthy sedentary males who did not actively exercise. The subjects had a mean age of 22.20±0.24 years, a mean height of 174.60±2.33 cm, and a mean weight of 69.70±2.42 kg. Two blood samples were collected from the subjects, one at rest, at 10:00 am, and the other immediately after strenuous exercise. Likewise, blood samples were taken from the same group of subjects after 48 hours: at 24:00 hours at rest and immediately after strenuous exercise. Samples were analyzed using the ELISA method to determine the serum melatonin levels (pg/ml). Results: By comparing the values at rest and after exercise, it was found that serum melatonin values remained unchanged with exercise. Serum melatonin values at rest or post-exercise measured at night were higher when compared with those measured during the day (p<0.05). Conclusions: Higher levels of melatonin found in the study appear to result from the increased release of melatonin at night, and not from exercise. The results of this study indicate that strenuous exercise carried out day or night, did not significantly influence serum melatonin levels

A combined method for estimating ventilatory threshold

Background. The aims of this study were to compare two new methods (D-max and CUSUM) for determination of the ventilatory threshold and to examine the consequences of estimation by application of these methods in combination

CEREBRAL BLOOD FLOW AND METABOLISM DURING VERTICAL IMMERSION AND IN-WATER EXERCISE

Vertical head-out water immersion has different physiological effects on the human body system due to hydrostatic pressure and different water temperatures. This review examines the changes in cerebral blood flow and metabolism during head-out water immersion and in-water exercise. Systematic research was conducted in PubMed, ScienceDirect, Scopus databases, by binary research methods. It included 11 articles that met the inclusion criteria. Studies have shown that acutely vertical head-out immersion in thermoneutral water and in-water exercise positively affects the circulation and metabolism of the brain. In healthy people, vertical immersion in thermoneutral water increases brain activity by increasing cerebral artery velocity and oxygenation. But, acutely, immersion in hot and cold water does not have a positive effect on cerebral circulation

The effect of pinealectomy and zinc deficiency on nitric oxide levels in rats with induced Toxoplasma gondii infection

Principles: This study aims at investigating how zinc deficiency and pinealectomy affect nitric oxide levels in rats infected by Toxoplasma gondii. Methods: The study was conducted on a total of 50 adult, male rats of Spraque-Dawley species. The study groups were as follows: General, intact control group (Group I, n = 10), infected control group (Group II, n = 10), infected and zinc-deficient group (Group III, n = 10), infected and pincalectomized group (Group IV, n = 10), infected, zinc-deficient and pinealectomized group (Group V, n = 10). After the experiment the rats were decapitated and levels of zinc, melatonin and total nitrite were identified in the blood samples collected. Results: The total nitrite levels in groups TV and V were more than those in all other groups (p <0.01). The total nitrite levels in Group II were also higher than those in Groups I and III (p <0.01). Plasma zinc levels in the zinc-deficient group and zinc-deficient and pinealectomized group were lower than those in all other groups, while melatonin levels were lower in Infected pinealectomized group (Group IV) and infected, zinc-deficient and pinealectomized group (Group V) than all others (p <0.01). Conclusions: The present study shows that plasma nitric oxide levels increase during Toxoplasma gondii infection, but this increase becomes more apparent in the presence of melatonin deficiency and is inhibited by zinc deficiency

The Effect of the Playing Positions in Basketball on Measures of Cognitive Performance

PurposeTo compete at a high-performance level, an athlete needs not only extraordinary physical capabilities but also extraordinary cognitive capabilities. However, position-specific differences concerning cognitive performance capabilities in team sport athletes (e.g., basketball) have, so far, not been extensively studied. Thus, this study investigated possible position-specific differences in specific cognitive performance capabilities in a cohort of trained basketball athletes playing guard, forward, or center positions for more than 10 years.Methods27 male basketball players and 20 sedentary controls were included in this study. We used three cognitive tests (i.e., Change Detection Test, Timewall Test, and Mackworth Clock Test) to investigate possible cognitive performance differences concerning position-specific capabilities. Thereto, indices of cognitive performance were compared between the athletes of the different playing positions and sedentary controls.ResultsIn the Change Detection Test, the number of correct answers from guards was significantly higher than the one of the forwards, centers, and sedentary controls (p < .001). During the Timewall Test, centers' timing scores were significantly higher than the one of the guards, forwards, and sedentary controls (p < .001). Concerning the Mackworth Clock Test, no significant differences between the playing positions were observed, although all basketball players outperformed sedentary controls.ConclusionIn summary, the results of this cross-sectional study provide evidence (i) that trained basketball players are equipped with superior cognitive capabilities as compared to sedentary controls, and (ii) that in trained basketball players position-related differences in specific cognitive capabilities occur. In regard to the latter, our findings suggest that guards are equipped with superior visuospatial attention and short-term memory capabilities whereas centers showed superior visuospatial perception and timing abilities. Whether such differences are caused by long-term position-specific training, are a result of a selection process, or a result of both factors needs to be investigated in future longitudinal studies