Intraoperative Hemi-Diaphragm Electrical Stimulation Demonstrates Attenuated Mitochondrial Function without Change in Oxidative Stress in Cardiothoracic Surgery Patients.

Mechanical ventilation during cardiothoracic surgery is life-saving but can lead to ventilator-induced diaphragm dysfunction (VIDD) and prolong ventilator weaning and hospital length of stay. Intraoperative phrenic nerve stimulation may preserve diaphragm force production to offset VIDD; we also investigated changes in mitochondrial function after stimulation. During cardiothoracic surgeries (n = 21), supramaximal, unilateral phrenic nerve stimulation was performed every 30 min for 1 min. Diaphragm biopsies were collected after the last stimulation and analyzed for mitochondrial respiration in permeabilized fibers and protein expression and enzymatic activity of biomarkers of oxidative stress and mitophagy. Patients received, on average, 6.2 ± 1.9 stimulation bouts. Stimulated hemidiaphragms showed lower leak respiration, maximum electron transport system (ETS) capacities, oxidative phosphorylation (OXPHOS), and spare capacity compared with unstimulated sides. There were no significant differences between mitochondrial enzyme activities and oxidative stress and mitophagy protein expression levels. Intraoperative phrenic nerve electrical stimulation led to an acute decrease of mitochondrial respiration in the stimulated hemidiaphragm, without differences in biomarkers of mitophagy or oxidative stress. Future studies warrant investigating optimal stimulation doses and testing post-operative chronic stimulation effects on weaning from the ventilator and rehabilitation outcomes.

Caffeine effects on systemic metabolism, oxidative-inflammatory pathways, and exercise performance.

Caffeine, a xanthine alkaloid compound, is consumed widely and daily by humans, as it is present in several regular beverages such as tea, coffee, soda beverages, and some drugs. Its consumption triggers arousal and alertness, improves mood, and causes the release of catecholamines, which induce beneficial effects on human behavior. Nonetheless, caffeine has been related to other beneficial effects such as antioxidant and anti-inflammatory actions that are extremely important to human health, altering the cellular redox and inflammatory status in a dose-dependent manner. Caffeine intake has also shown ergogenic effects, which are attributed to different factors, such as enhanced substrate utilization, fatigue delay, and alertness. As such, caffeine has been consumed by athletes from different sports modalities, with positive and negative effects declared. Although peripheral tissues such as the heart, skeletal muscle, and adipocytes are also impacted, there is a deficit of recognized mechanisms in systemic metabolism when compared to caffeine action in the central nervous system. This review summarizes the most relevant classical and current literature available regarding the use of caffeine in different metabolic situations, such as oxidative and inflammatory status, as well as anaerobic and aerobic physical exercises. Here, we identified the non-central nervous system caffeine mechanisms modulation, as most are still unknown or controversial, highlighting its influence in the peripheral system and its essential and crucial impacts on the human's organism adaptation.

Diclofenac attenuates inflammation through TLR4 pathway and improves exercise performance after exhaustive swimming.

BACKGROUND: The use of NSAIDs has become a common practice to counteract the pro-inflammatory acute effects of exercise, in order to improve sports performance. The liver, due to its central role in energy metabolism, may be involved primarily in the process of ROS generation and consequently inflammation after exhaustive exercise. OBJECTIVE: To analyze the influence of diclofenac on the liver TLR4 pathway and time to exhaustion in rats submitted to repeated exhaustive swimming. METHODS: An exhaustive test was performed in order to mimic athletes' routine, and inflammatory status and oxidative stress markers were evaluated in the liver. Animals were divided into sedentary and exhaustion groups, with this last performing three exhaustive swimming bouts. At the same time, diclofenac or saline was pre-administered once a day for nine days. RESULTS: Data showed significantly increased COX-2, TLR4, and MyD88 protein content in the liver after exhaustive swimming bouts. The levels of pro-inflammatory cytokines also increased after exhaustive exercise, while these effects were attenuated in the group treated with diclofenac plus exhaustive swimming bouts. The anti-inflammatory modulation provoked by diclofenac treatment was associated with an increased time to exhaustion in the exercise bouts. The exhaustive exercise increased TBARS formation, but diclofenac treatment blunted this elevation, while GSH/GSSG ratios in both exhaustion-saline and exhaustion-diclofenac-treated groups were lower than in the sedentary-saline group. CONCLUSIONS: Our findings suggest that diclofenac may improve exercise performance and represent an effective tool to ameliorate the pro-inflammatory status in liver when associated with exhaustive exercise, and the liver may be a possible therapeutic target.

High-intensity interval training improves inflammatory and adipokine profiles in postmenopausal women with metabolic syndrome.

This study investigate the effects of high-intensity interval training (HIIT) on systemic levels of inflammatory and hormonal markers in postmenopausal women with metabolic syndrome (MS). Fifteen postmenopausal women with MS completed the training on treadmills. Functional, body composition parameters, maximal oxygen uptake (VO2max), and lipid profile were assessed before and after HIIT. Serum or plasma levels of cytokines and hormonal markers were measured along the intervention. The analysis of messenger RNA (mRNA) expression of these cytokines was performed in peripheral blood mononuclear cells (PBMC). VO2max and some anthropometric parameters were improved after HIIT, while decreased levels of proinflammatory markers and increased levels of interleukin-10 (IL-10) were also found. Adipokines were also modulated after 12 weeks or training. The mRNA expression of the studied genes was unchanged after HIIT. In conclusion, HIIT benefits inflammatory and hormonal axis on serum or plasma samples, without changes on PBMC of postmenopausal MS patients.

Modulación antioxidante y antiinflamatoria del ejercicio físico durante el envejecimiento / Antioxidant and anti-inflammatory modulation of exercise during aging

El proceso de envejecimiento se caracteriza por la pérdida gradual de la reserva funcional, lo cual, asociado a la adopción de hábitos de vida sedentarios y al incremento de factores de riesgo, se traduce en un deterioro de la defensa antioxidante y en un aumento de los niveles circulantes de marcadores inflamatorios y oxidativos. Estos fenomenos incrementan el estado de inflamacion cronica de bajo grado, denominado inflamm-aging, presente en la etiopatología de cuadros crónicos y procesos de deterioro cognitivo asociados a la edad. El objetivo de esta revisión es describir el efecto modulador antioxidante y antiinflamatorio del ejercicio físico de moderada intensidad y volumen durante el envejecimiento. Se presenta evidencia de su efectividad como herramienta no farmacológica, orientada a aminorar los efectos deletéreos del envejecimiento, debido en gran parte a su acción neuroprotectora, incremento de marcadores antiinflamatorios circulantes y mejora de la defensa antioxidante derivados de su práctica

Aging is characterised by a gradual loss of the functional reserve. This, along with the fostering of sedentary habits and the increase in risk factors, causes a deterioration of antioxidant defences and an increase of the circulatory levels of inflammatory and oxidative markers, boosting a low-rate chronic inflammation, defined as inflamm-aging. This phenomenon is present in the aetiopathology of chronic diseases, as well as in cognitive deterioration cases associated with aging. The objective of this review is to describe the modulation of antioxidant and anti-inflammatory effects of physical exercise of moderate intensity and volume in the elderly. Evidence of its effectiveness as a non-pharmacological resource is presented, which decreases some deleterious effects of aging. This is mainly due to its neuroprotective action, the increase in circulating anti-inflammatory markers, and the improvement of antioxidant defence derived from its practice

[Antioxidant and anti-inflammatory modulation of exercise during aging]. / Modulación antioxidante y antiinflamatoria del ejercicio físico durante el envejecimiento.

Aging is characterised by a gradual loss of the functional reserve. This, along with the fostering of sedentary habits and the increase in risk factors, causes a deterioration of antioxidant defences and an increase of the circulatory levels of inflammatory and oxidative markers, boosting a low-rate chronic inflammation, defined as inflamm-aging. This phenomenon is present in the aetiopathology of chronic diseases, as well as in cognitive deterioration cases associated with aging. The objective of this review is to describe the modulation of antioxidant and anti-inflammatory effects of physical exercise of moderate intensity and volume in the elderly. Evidence of its effectiveness as a non-pharmacological resource is presented, which decreases some deleterious effects of aging. This is mainly due to its neuroprotective action, the increase in circulating anti-inflammatory markers, and the improvement of antioxidant defence derived from its practice.

[Effects of high-intensity interval training and nutritional education in patients with type 2 diabetes]. / Ejercicio intermitente y consejería nutricional mejoran control glicémico y calidad de vida en pacientes con diabetes mellitus tipo 2.

BACKGROUND: High-intensity interval training (HIIT) improves cardiometabolic markers, but its effects on the quality of life of patients with type 2 diabetes (T2D) is not well known. AIM: To determine the effects of a 12-week HIIT exercise program on cardiometabolic and quality of life variables of T2D patients. MATERIAL AND METHODS: Nine T2D women were assigned to a HIIT + nutritional education (GE) and 10, to a nutritional education alone group (GC). At baseline and after each intervention, anthropometric and body composition parameters using bio-impedance were assessed, and a blood sample was obtained to measure serum lipid levels, blood glucose and glycated hemoglobin. Quality of life was assessed using the SF-12 questionnaire adapted for the Chilean population. RESULTS: There were no significant changes on the lipid profile variables in the GE group, although HDL cholesterol was increased significantly (p < 0.05) in the GC group. Total fat mass was decreased in the GE group from 43.5 ± 1.5 to 41.9 ± 1.5%, p < 0.01. Fasting glucose and glycated hemoglobin decreased in the GE group. There was a significant correlation between the decrease in total fat mass and that of glycated hemoglobin. There were significant increases in quality of life parameters; physical function, physical role, pain, general health, vitality, emotional role, mental health, and social function in the GE but not in the GC group. CONCLUSIONS: A 12-week program of HIIT plus nutritional education improves cardiometabolic and quality of life parameters on type 2 diabetics.

Functional and biochemical adaptations of elite level futsal players from Brazil along a training season.

BACKGROUND AND OBJECTIVE: Although hard training is mandatory in elite level futsal training, few studies have proposed a biochemical follow up in futsal players during a whole season. Therefore, the aim of this study was to compare functional and biochemical markers in Brazilian elite level futsal players throughout a competition season. MATERIALS AND METHODS: Eight players aged 25.5±5.4 years were evaluated at three time points: preseason (T1), immediately before the FIFA®-Intercontinental-Futsal-Cup (T2), and at the end of the season (T3), with a tapering period of 1 week before T2. Functional parameters (weight, height, body fat, VO2max, heart rate, and distance ran) and blood sampling for cell count and lipid profile (cholesterol, HDL-C, LDL-C, triglycerides) were assessed at each time point. After, a Yo-Yo R2 test was carried out in each time point (T1, T2 and T3) and blood samples to assess skeletal muscle damage (creatine kinase [CK], lactate dehydrogenase [LDH]), inflammation (C-reactive protein [CRP]) and oxidative stress markers (ischemia modified albumin [IMA], and advanced oxidation protein products [AOPP]) were obtained before and after the tests. RESULTS: Although functional parameters did not change throughout the season, greater total number of erythrocytes (P≤0.05), and hemoglobin (P≤0.05) were found at T2 compared to T1. Similarly, lower LDH (P≤0.05) and CK (P≤0.05) levels were found at T2 compared to T1. CPR levels were also decreased at T2 in comparison to T1 both before and after Yo-Yo R2 test (P≤0.05), while IMA and AOPP levels showed only a season effect (P≤0.05). CONCLUSIONS: The tapering strategy was successful considering players presented lower levels of muscle damage, inflammation and oxidative stress makers before T2, which preceded the main championship of the year. These results are of great relevance, considering the team won the FIFA®-Intercontinental-Futsal-Cup, which happened at T2. Thus, it seems that routine-based biochemical markers may be useful as training control means in this population.

Previous physical exercise alters the hepatic profile of oxidative-inflammatory status and limits the secondary brain damage induced by severe traumatic brain injury in rats.

KEY POINTS: An early inflammatory response and oxidative stress are implicated in the signal transduction that alters both hepatic redox status and mitochondrial function after traumatic brain injury (TBI). Peripheral oxidative/inflammatory responses contribute to neuronal dysfunction after TBI Exercise training alters the profile of oxidative-inflammatory status in liver and protects against acute hyperglycaemia and a cerebral inflammatory response after TBI. Approaches such as exercise training, which attenuates neuronal damage after TBI, may have therapeutic potential through modulation of responses by metabolic organs. The vulnerability of the body to oxidative/inflammatory in TBI is significantly enhanced in sedentary compared to physically active counterparts. ABSTRACT: Although systemic responses have been described after traumatic brain injury (TBI), little is known regarding potential interactions between brain and peripheral organs after neuronal injury. Accordingly, we aimed to investigate whether a peripheral oxidative/inflammatory response contributes to neuronal dysfunction after TBI, as well as the prophylactic role of exercise training. Animals were submitted to fluid percussion injury after 6 weeks of swimming training. Previous exercise training increased mRNA expression of X receptor alpha and ATP-binding cassette transporter, and decreased inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor (TNF)-α and interleukin (IL)-6 expression per se in liver. Interestingly, exercise training protected against hepatic inflammation (COX-2, iNOS, TNF-α and IL-6), oxidative stress (decreases in non-protein sulfhydryl and glutathione, as well as increases in 2',7'-dichlorofluorescein diacetate oxidation and protein carbonyl), which altered hepatic redox status (increases in myeloperoxidase and superoxide dismutase activity, as well as inhibition of catalase activity) mitochondrial function (decreases in methyl-tetrazolium and Δψ, as well as inhibition of citrate synthase activity) and ion gradient homeostasis (inhibition of Na+ ,K+ -ATPase activity inhibition) when analysed 24 h after TBI. Previous exercise training also protected against dysglycaemia, impaired hepatic signalling (increase in phosphorylated c-Jun NH2-terminal kinase, phosphorylated decreases in insulin receptor substrate and phosphorylated AKT expression), high levels of circulating and neuronal cytokines, the opening of the blood-brain barrier, neutrophil infiltration and Na+ ,K+ -ATPase activity inhibition in the ipsilateral cortex after TBI. Moreover, the impairment of protein function, neurobehavioural (neuromotor dysfunction and spatial learning) disability and hippocampal cell damage in sedentary rats suggests that exercise training also modulates peripheral oxidative/inflammatory pathways in TBI, which corroborates the ever increasing evidence regarding health-related outcomes with respect to a physically active lifestyle.

Ejercicio intermitente y consejería nutricional mejoran control glicémico y calidad de vida en pacientes con diabetes mellitus tipo 2 / Effects of high-intensity interval training and nutritional education in patients with type 2 diabetes

Background: High-intensity interval training (HIIT) improves cardiometabolic markers, but its effects on the quality of life of patients with type 2 diabetes (T2D) is not well known. Aim: To determine the effects of a 12-week HIIT exercise program on cardiometabolic and quality of life variables of T2D patients. Material and Methods: Nine T2D women were assigned to a HIIT + nutritional education (GE) and 10, to a nutritional education alone group (GC). At baseline and after each intervention, anthropometric and body composition parameters using bio-impedance were assessed, and a blood sample was obtained to measure serum lipid levels, blood glucose and glycated hemoglobin. Quality of life was assessed using the SF-12 questionnaire adapted for the Chilean population. Results: There were no significant changes on the lipid profile variables in the GE group, although HDL cholesterol was increased significantly (p < 0.05) in the GC group. Total fat mass was decreased in the GE group from 43.5 ± 1.5 to 41.9 ± 1.5%, p < 0.01. Fasting glucose and glycated hemoglobin decreased in the GE group. There was a significant correlation between the decrease in total fat mass and that of glycated hemoglobin. There were significant increases in quality of life parameters; physical function, physical role, pain, general health, vitality, emotional role, mental health, and social function in the GE but not in the GC group. Conclusions: A 12-week program of HIIT plus nutritional education improves cardiometabolic and quality of life parameters on type 2 diabetics.

ALA16VAL-MnSOD gene polymorphism and stroke: Association with dyslipidemia and glucose levels.

Stroke risk has been associated to the progression of carotid plaques due to high glucose levels and lipid accumulation, which are greatly associated to cerebral injury, brain oxidative stress, and apoptosis. The ALA16VAL-MnSOD gene single nucleotide polymorphism (SNP) has shown to modulate risk factors of several metabolic and vascular diseases, such as blood glucose (GLU) and lipid levels. However, the association of these factors in stroke patients has not been studied to date. Thus, we evaluated the influence of the Ala16Val-MnSOD SNP on lipid profile, GLU levels, oxidative and DNA damage of 44 patients in a late phase of stroke (>6months). The statistical analysis showed a greater proportion of VV carries in stroke patients. The results also indicated that stroke patients had higher cholesterol (CHO) and GLU levels when compared to healthy counterparts. Interestingly, V allele carriers with stroke showed higher levels of CHO and GLU when compared to AA stroke and healthy counterparts. Our findings suggest that oxidative stress markers are still increased even after 6 months of cerebral injury. Furthermore, we propose that the Ala16Val-MnSOD SNPs may contribute to hypercholesterolemia and higher GLU levels, increasing the risk to neurovascular events that may lead to stroke.

Diclofenac pretreatment modulates exercise-induced inflammation in skeletal muscle of rats through the TLR4/NF-κB pathway.

Nonsteroidal anti-inflammatory drugs, such as diclofenac, are widely used to treat inflammation and pain in several conditions, including sports injuries. This study analyzes the influence of diclofenac on the toll-like receptor-nuclear factor kappa B (TLR-NF-κB) pathway in skeletal muscle of rats submitted to acute eccentric exercise. Twenty male Wistar rats were divided into 4 groups: control-saline, control-diclofenac, exercise-saline, and exercise-diclofenac. Diclofenac or saline were administered for 7 days prior to an acute eccentric exercise bout. The inflammatory status was evaluated through mRNA levels of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6), IL-1ß, and tumor necrosis factor alpha (TNF-α), and protein content of COX-2, IL-6, and TNF-α in vastus lateralis muscle. Data obtained showed that a single bout of eccentric exercise significantly increased COX-2 gene expression. Similarly, mRNA expression and protein content of other inflammation-related genes also increased after the acute exercise. However, these effects were attenuated in the exercise + diclofenac group. TLR4, myeloid differentiation primary response gene 88 (MyD88), and p65 were also upregulated after the acute eccentric bout and the effect was blunted by the anti-inflammatory drug. These findings suggest that pretreatment with diclofenac may represent an effective tool to ameliorate the pro-inflammatory status induced by acute exercise in rat skeletal muscle possibly through an attenuation of the TLR4-NF-κB signaling pathway.

Oxidative stress and inflammation: liver responses and adaptations to acute and regular exercise.

The liver is remarkably important during exercise outcomes due to its contribution to detoxification, synthesis, and release of biomolecules, and energy supply to the exercising muscles. Recently, liver has been also shown to play an important role in redox status and inflammatory modulation during exercise. However, while several studies have described the adaptations of skeletal muscles to acute and chronic exercise, hepatic changes are still scarcely investigated. Indeed, acute intense exercise challenges the liver with increased reactive oxygen species (ROS) and inflammation onset, whereas regular training induces hepatic antioxidant and anti-inflammatory improvements. Acute and regular exercise protocols in combination with antioxidant and anti-inflammatory supplementation have been also tested to verify hepatic adaptations to exercise. Although positive results have been reported in some acute models, several studies have shown an increased exercise-related stress upon liver. A similar trend has been observed during training: while synergistic effects of training and antioxidant/anti-inflammatory supplementations have been occasionally found, others reported a blunting of relevant adaptations to exercise, following the patterns described in skeletal muscles. This review discusses current data regarding liver responses and adaptation to acute and regular exercise protocols alone or combined with antioxidant and anti-inflammatory supplementation. The understanding of the mechanisms behind these modulations is of interest for both exercise-related health and performance outcomes.

Increased xanthine oxidase-related ROS production and TRPV1 synthesis preceding DOMS post-eccentric exercise in rats.

AIMS: It is well-known that unaccustomed exercise, especially eccentric exercise, is associated to delayed onset muscle soreness (DOMS). Whether DOMS is associated with reactive oxygen species (ROS) and the transient receptor potential vanilloid 1 (TRPV1) is still an open question. Thus, the aim of this study was to investigate the association between TRPV1 and xanthine oxidase-related ROS production in muscle and DOMS after a bout of eccentric exercise. MAIN METHODS: Male Wistar rats performed a downhill running exercise on a treadmill at a -16° tilt and a constant speed for 90min (5min/bout separated by 2min of rest). Mechanical allodynia and grip force tests were performed before and 1, 3, 6, 9, 12, 24, 48 and 72h after the downhill running. Biochemical assays probing oxidative stress, purine degradation, xanthine oxidase activity, Ca(2+) ATPase activity and TRPV1 protein content were performed in gastrocnemius muscle at 12, 24, and 48h after the downhill running. KEY FINDINGS: Our statistical analysis showed an increase in mechanical allodynia and a loss of strength after the downhill running. Similarly, an increase in carbonyl, xanthine oxidase activity, uric acid levels and TRPV1 immunoreactivity were found 12h post-exercise. On the other hand, Ca(2+) ATPase activity decreased in all analyzed times. SIGNIFICANCE: Our results suggest that a possible relationship between xanthine oxidase-related ROS and TRPV1 may exist during the events preceding eccentric exercise-related DOMS.

Diclofenac pretreatment effects on the toll-like receptor 4/nuclear factor kappa B-mediated inflammatory response to eccentric exercise in rat liver.

UNLABELLED: Acute exercise is a stress stimulus that may cause cell damage through the activation of the toll-like receptor (TLR)4 pathway, resulting in the translocation of nuclear factor kappa B (NF-κB) into the cell nucleus and the upregulation of inflammatory genes. Nonsteroidal anti-inflammatory drugs, such as diclofenac, are often prescribed to counteract exercise-induced inflammation. AIMS: This study analyzed effects of diclofenac pretreatment on the TLR4/NF-κB pathway in rat liver after an acute eccentric exercise. MAIN METHODS: Twenty male Wistar rats were divided in four groups: control-saline, control-diclofenac, exercise-saline and exercise-diclofenac. The rats received saline or diclofenac (10mg/kg) for 7days prior to an eccentric exercise bout. KEY FINDINGS: After exercise there was an increase in TLR4, myeloid differentiation primary response gene 88 (MyD88), TIR domain-containing adaptor inducing interferon (TRIF) and p65 NF-κB subunit protein levels. Exercise also resulted in increased mRNA and protein expression of interleukin (IL)-6, inducible nitric oxide synthase (iNOS) and tumor necrosis factor (TNF)-α. Proinflammatory effects of exercise were prevented by the administration of diclofenac, which blunted the activation of the TLR4/NF-κB pathway and the inflammatory response in the liver of exercised rats. SIGNIFICANCE: Results from the present study highlight the role of TLR4 as a target for anti-inflammatory interventions.

Response of oxidative stress and inflammatory biomarkers to a 12-week aerobic exercise training in women with metabolic syndrome.

BACKGROUND: Evidences have been highlighted the relationship among metabolic syndrome, chronic low-grade inflammation, oxidative stress and several diseases. In this sense, the aim of this study was to investigate the effects of aerobic exercise training on oxidative stress and inflammatory parameters on women with metabolic syndrome (MS). METHODS: Twenty-three untrained women (51.86 ± 6.58 years old, BMI 30.8 ± 4.3 kg/m2) completed a 12-week treadmill exercise training, without modifications on dietary pattern. Advanced oxidation protein products (AOPP), thiobarbituric acid-reactive substances (TBARS), total thiol content (T-SH) and nitrite and nitrate (NOx) levels were assessed in plasma while the levels of interleukin-1 beta (IL-1ß), interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor alpha (TNF-α) and interferon-gamma (IFN-γ) were evaluated in the serum. The RNA expression (mRNA) of IL-1ß, IL-10, TNF-α, IFN-γ, insulin receptor substrate 2 (IRS-2) and matrix metalloproteinase-9 (MMP-9) were performed inperipheral blood mononuclear cells (PBMC) of a subset with eight women with MS using real real-time polymerase chain reaction (qPCR). RESULTS: The intervention resulted in decreased serum levels of IL-1ß, IL-6, TNF-α, IFN-γ, AOPP and TBARS, besides increased levels of IL-10 and T-SH (P < 0.001). NOx concentrations were unchanged, similarly to mRNA expressions quantified in PBMC. CONCLUSIONS: Twelve weeks of AT improved systemic oxidative stress and inflammatory biomarkers in women with MS, although PBMC mRNA expression for inflammatory pathways appeared to be unchanged. This may indicate that AT induced beneficial effects not only in physical fitness but also on health promotion through decreased oxidative damage and proinflammatory status.

Manganese superoxide dismutase and oxidative stress modulation.

Oxidative stress is characterized by imbalanced reactive oxygen species (ROS) production and antioxidant defenses. Two main antioxidant systems exist. The nonenzymatic system relies on molecules to directly quench ROS and the enzymatic system is composed of specific enzymes that detoxify ROS. Among the latter, the superoxide dismutase (SOD) family is important in oxidative stress modulation. Of these, manganese-dependent SOD (MnSOD) plays a major role due to its mitochondrial location, i.e., the main site of superoxide (O(2)(·-)) production. As such, extensive research has focused on its capacity to modulate oxidative stress. Early data demonstrated the relevance of MnSOD as an O(2)(·-) scavenger. More recent research has, however, identified a prominent role for MnSOD in carcinogenesis. In addition, SOD downregulation appears associated with health risk in heart and brain. A single nucleotide polymorphism which alters the mitochondria signaling sequence for the cytosolic MnSOD form has been identified. Transport into the mitochondria was differentially affected by allelic presence and a new chapter in MnSOD research thus begun. As a result, an ever-increasing number of diseases appear associated with this allelic variation including metabolic and cardiovascular disease. Although diet and exercise upregulate MnSOD, the relationship between environmental and genetic factors remains unclear.

An active lifestyle induces positive antioxidant enzyme modulation in peripheral blood mononuclear cells of overweight/obese postmenopausal women.

AIMS: The aim of this study was to investigate the effects of an active lifestyle on mitochondrial functioning, viability, bioenergetics, and redox status markers in peripheral blood mononuclear cells (PBMC) of overweight/ obese postmenopausal women. MATERIALS AND METHODS: We performed a cross-sectional study with postmenopausal women aged 45­64 years and body mass index N 25 kg/m2, divided into physically active (n = 23) and sedentary (n = 12) groups. Mitochondria functioning and viability, bioenergetics and redox status parameters were assessed in PBMC with spectrophotometric and fluorometric assays. KEY FINDINGS: No differences were found in the enzyme activity of complexes I and II of the electron transport chain (ETC), mitochondrial superoxide dismutase (MnSOD) activity, methyl-tetrazolium reduction levels and reduced glutathione and oxidized glutathione levels between the groups. However, the physically active group presented higher levels of reactive oxygen species (ROS) (P= 0.04) and increased catalase (CAT) (P= 0.029), total (P= 0.011) and cytosolic SOD (CuZnSOD) (P= 0.009) activities. SIGNIFICANCE: An active lifestyle that includes aerobic exercise for at least 30 min, three times per week may improve antioxidant enzyme activities in PBMC in overweight/obese postmenopausal women, without changes in the activity of the ETC enzymes. However, this low intensity physical activity is not able to induce relevant mitochondrial adaptations.

Critical periods in the variation in body composition in school children.

OBJECTIVE: To identify critical periods in the variation in body composition during a school year and determine possible causes. METHODS: A total of 363 boys and girls aged between 10 and 14 years participated in the study. Before and after the Winter Holidays (WIH) and National Holidays (NAH) (July and September, respectively), measurements were taken of body weight, body fat percentage, waist perimeter, time spent on physical activity and hours of sleep in order to determine the variations. The normality of the data was confirmed and the means were compared with an alpha significance level of p<0.05. RESULTS: The school children increased in weight by 600 g and 510 g in the NAH and WIH, respectively (p<0.0001), and their body fat percentage was significantly increased during both periods (0.51%); however, the waist perimeter measurement saw no significant changes. It can also be seen that in NAH physical activity dropped by an important amount (-41 min, p<0.0001), though this did not occur in WIH. A significant increase in hours of sleep was also seen during the two holiday periods (~1 to 2 hours/day). CONCLUSION: It is concluded that both NAH and WIH can be considered critical periods due to the sharp increase in body weight and body fat percentage in the school children, where a possible cause is the reduction in time spent on physical activity.

Objetivo: Identificar periodos críticos en la variación de la composición corporal durante un año escolar y determinar causas posibles. Métodos: Un total de 363 niños y niñas entre 10 y 14 años participaron en el estudio. Antes y después de las Vacaciones de invierno (VI) y Vacaciones nacionales (VN) (julio y septiembre, respectivamente), se tomaron mediciones de peso corporal, porcentaje de grasa corporal, perímetro en la cintura, tiempo dedicado a actividad física y horas de sueño para determinar las variaciones. La normalidad de los datos fue confirmada y las medias fueron comparadas con un nivel de significancia alfa de p.