Short-term physical exercise controls age-related hyperinsulinemia and improves hepatic metabolism in aged rodents.

PURPOSE: Aging is associated with changes in glucose homeostasis related to both decreased insulin secretion and/or impaired insulin action, contributing to the high prevalence of type 2 diabetes (T2D) in the elderly population. Additionally, studies are showing that chronically high levels of circulating insulin can also lead to insulin resistance. In contrast, physical exercise has been a strategy used to improve insulin sensitivity and metabolic health. However, the molecular alterations resulting from the effects of physical exercise in the liver on age-related hyperinsulinemia conditions are not yet fully established. This study aimed to investigate the effects of 7 days of aerobic exercise on hepatic metabolism in aged hyperinsulinemic rats (i.e., Wistar and F344) and in Slc2a4+/- mice (hyperglycemic and hyperinsulinemic mice). RESULTS: Both aged models showed alterations in insulin and glucose tolerance, which were associated with essential changes in hepatic fat metabolism (lipogenesis, gluconeogenesis, and inflammation). In contrast, 7 days of physical exercise was efficient in improving whole-body glucose and insulin sensitivity, and hepatic metabolism. The Slc2a4+/- mice presented significant metabolic impairments (insulin resistance and hepatic fat accumulation) that were improved by short-term exercise training. In this scenario, high circulating insulin may be an important contributor to age-related insulin resistance and hepatic disarrangements in some specific conditions. CONCLUSION: In conclusion, our data demonstrated that short-term aerobic exercise was able to control mechanisms related to hepatic fat accumulation and insulin sensitivity in aged rodents. These effects could contribute to late-life metabolic health and prevent the development/progression of age-related T2D.

Correlations between resistance training-induced changes on phase angle and biochemical markers in older women.

The main purpose of this study was to investigate the effects of 12 weeks of resistance training (RT) on phase angle (PhA), inflammatory and oxidative stress biomarkers, and to evaluate whether these RT-induced adaptations are related to PhA changes. Fifty-one older women (70.6 ± 5.1 years; 26.9 ± 4.2 kg/m2 ) were randomly allocated into a training group (TG) that performed 12-week RT or a nonexercising control group (CG). The PhA (Xitron), body composition (DXA), and blood sample measurements (after a 12 hours fast) were performed before and after the intervention. The TG showed a significant (P < .05) increase in PhA (TG: +7.4±5.9% vs CG: -3.6 ± 8.8%), and interleukin-10 (IL-10; TG: +51.8 ± 71.1% vs CG: -46.6 ± 38.0%), and a decrease in tumor necrosis factor alpha (TNF-α; TG: -15.2 ± 11.1% vs CG: +6.9±17.7%), interleukin-6 (IL-6; TG: -17.9 ± 17.8% vs CG: +6.1 ± 24.8%), and C-reactive protein (CRP; TG: -24.1 ± 19.9% vs CG: +43.8 ± 31.1%). Moreover, TG upregulated catalase (TG: +11.4 ± 15.0% vs CG: -6.7 ± 10.2%). Changes in TNF-α (r = -.71), CRP (r = -.65), lower advanced oxidation protein products (r = -.55), and catalase (r = +.73) after RT were correlated with changes in PhA (P < .05). These results suggest that RT improves PhA, inflammatory and oxidative stress biomarkers, and the changes in inflammatory and oxidative damage markers are correlated with changes in PhA.

Effect of concurrent training with blood flow restriction in the elderly.

The aim of this present study was to investigate on the effects of concurrent training with blood flow restriction (BFR-CT) and concurrent training (CT) on the aerobic fitness, muscle mass and muscle strength in a cohort of older individuals. 25 healthy older adults (64.7±4.1 years; 69.33±10.8 kg; 1.6±0.1 m) were randomly assigned to experimental groups: CT (n=8, endurance training (ET), 2 days/week for 30-40 min, 50-80% VO(2peak) and RT, 2 days/week, leg press with 4 sets of 10 reps at 70-80% of 1-RM with 60 s rest), BFR-CT (n=10, ET, similar to CT, but resistance training with blood flow restriction: 2 days/week, leg press with 1 set of 30 and 3 sets of 15 reps at 20-30% 1-RM with 60 s rest) or control group (n=7). Quadriceps cross-sectional area (CSAq), 1-RM and VO(2peak) were assessed pre- and post-examination (12 wk). The CT and BFR-CT showed similar increases in CSAq post-test (7.3%, P<0.001; 7.6%, P<0.0001, respectively), 1-RM (38.1%, P<0.001; 35.4%, P=0.001, respectively) and VO(2peak) (9.5%, P=0.04; 10.3%, P=0.02, respectively). The BFR-CT promotes similar neuromuscular and cardiorespiratory adaptations as CT.

Neuromuscular and metabolic characteristics of elite basketball referees.

AIM: The dynamics of Basketball refereeing has changed and more recently the championships started to use the participation of three referees, but there is still a lack of information about the physical characteristics and performance of the referees. The aim of this study was to characterize the neuromuscular and metabolic performances and body composition of Brazilian elite basketball referees, with a level of national and international refereeing. METHODS: Thirty-seven referees participated in the study (international level N.=17 and national level N.=20). We evaluated anthropometric and body composition variables, among them: height, body mass, body mass index (BMI) and body fat (%); metabolic parameters: lactate at rest and post-exercise; and neuromuscular performance: speed, explosive lower limbs strength, flexibility and aerobic capacity. The main results showed a statistically significant difference in age, in which the international referees were older than the national level (41.94±6.71; 37.30±7.23; P=0.036). RESULTS: There were not significant differences between the levels for neuromuscular and metabolic parameters and body composition. Comparing the results with athletes, the referees showed lower neuromuscular and metabolic parameters and the body composition showed higher body fat than basketball players. CONCLUSION: These data may represent physiological parameters to be considered in the prescription of physical training during the preparation and competition period.

Arachidonic acid-containing phosphatidylcholine inhibits lymphocyte proliferation and decreases interleukin-2 and interferon-gamma production from concanavalin A-stimulated rat lymphocytes.

The proliferation of concanavalin A (Con A)-stimulated rat lymphocytes was markedly inhibited by phosphatidylcholine containing arachidonic and stearic acids (PC(A-S)), but not by phosphatidylcholine containing oleic and stearic acids or phosphatidylinositol containing arachidonic and stearic acids. The concentration of PC(A-S) which inhibited Con A-stimulated proliferation by 50% was 31 microM and near total inhibition was observed at 154 microM . Phosphatidylserine containing only oleic acid enhanced proliferation by 37% at a concentration of 31 microM , but phosphatidylethanolamine and phosphatidylcholine containing only oleic acid did not affect proliferation at this concentration. It is concluded that both the head group and the fatty acid composition contribute to the influence of phospholipids on lymphocyte proliferation. The effects of PC(A-S) on T-lymphocyte responses were investigated further. In parallel with the inhibition of proliferation PC(A-S) caused a concentration-dependent decrease in the production of the Th1-type cytokines interleukin (IL)-2 and interferon (IFN)-gamma; inhibition of cytokine production was >85% at the highest concentration of PC(A-S) used (154 microM ). Production of the Th2-type cytokines IL-4 and IL-10 was not affected. The possible role of prostaglandins in mediating the effects of PC(A-S) was examined by adding indomethacin into the medium and the participation of lipid peroxidation was examined by adding vitamin E and vitamin C. Indomethacin and vitamin E did not affect the inhibition caused by PC(A-S) but vitamin C caused a partial reversal. It is concluded that inhibition of T-lymphocyte proliferation by phospholipids involves both the head group and the fatty acyl chains, that this inhibition is not mediated by prostaglandins but may involve some form of oxidant stress and that some phospholipids (e.g., PC(A-S)) can markedly influence cytokine profiles.

MCT1 and MCT4 kinetic of mRNA expression in different tissues after aerobic exercise at maximal lactate steady state workload.

We evaluate the mRNA expression of monocarboxylate transporters 1 and 4 (MCT1 and MCT4) in skeletal muscle (soleus, red and white gastrocnemius), heart and liver tissues in mice submitted to a single bout of swimming exercise at the maximal lactate steady state workload (MLSSw). After 72 h of MLSS test, the animals were submitted to a swimming exercise session for 25 min at individual MLSSw. Tissues and muscle samples were obtained at rest (control, n=5), immediately (n=5), 5 h (n=5) and 10 h (n=5) after exercise for determination of the MCT1 and MCT4 mRNA expression (RT-PCR). The MCT1 mRNA expression in liver increased after 10 h in relation to the control, immediate and 5 h groups, but the MCT4 remained unchanged. The MCT1 mRNA expression in heart increased by 31 % after 10 h when compared to immediate, but no differences were observed in relation to the control group. No significant differences were observed for red gastrocnemius in MCT1 and MCT4 mRNA expression. However, white gastrocnemius increased MCT1 mRNA expression immediately when compared to rest, 5 and 10 h test groups. In soleus muscle, the MCT1 mRNA expression increased immediately, 5 and 10 h after exercise when compared to the control. In relation to MCT4 mRNA expression, the soleus increased immediately and 10 h after acute exercise when compared to the control group. The soleus, liver and heart were the main tissues that showed improved the MCT1 mRNA expression, indicating its important role in controlling MLSS concentration in mice.

Lymphocyte and cytokines after short periods of exercise.

The purpose of this study was to verify the effects of short periods of exercise of different intensity on lymphocyte function and cytokines. Thirty Wistar rats, 2 months old, were used. They were divided into five groups of six rats: a sedentary control group; a group exercised for 5 minutes at low intensity (5 L); a group exercised for 15 minutes at low intensity (15 L); and groups exercised at moderate intensity (additional load of 5 % of body weight) for 5 minutes (5 M) or for 15 minutes (15 M). The parameters measured were: total leukocytes, neutrophils, lymphocytes, monocytes, lymphocytes from lymph nodes, serum cytokines (IL-2, IL-6 and TNF-alpha), lymphocyte mitochondrial transmembrane potential, viability and DNA fragmentation. ANOVA two way followed by Tukey's post hoc test (p

Efeitos agudos do exercício de curta duração sobre a capacidade fagocitária de macrófagos peritoneais em ratos sedentários / Acute effects of short-duration exercise on the phagocytic capacity of peritoneal macrophages in sedentary rats

OBJETIVO: Analisar os efeitos agudos do exercício de curta duração em diferentes durações e intensidades sobre leucócitos totais, número e capacidade fagocitária de macrófagos peritoneais. MÉTODO: Foram utilizados ratos Wistar (n= 30, n= 6 por grupo), divididos em 5 grupos: controle sedentário (C); exercitados 5 minutos na intensidade leve ou moderada (5L e 5M, respectivamente); exercitados 15 minutos na intensidade leve ou moderada (15L e 15M, respectivamente). Na intensidade leve, o exercício foi realizado sem cargas; na moderada, foi utilizada carga adicional de 5 por cento do peso corporal dos animais em suas regiões dorsais. A contagem total de leucócitos e monócitos foi realizada no microscópio, cuja leitura foi procedida no aparelho LEUCOTRON TP. A porcentagem da fagocitose foi determinada por contagem em câmara de Neubauer através do número de células que fagocitaram três ou mais partículas de zymosan. Foram utilizados os testes ANOVA two way e Tukey com p < 0,05. RESULTADOS: Foi observado aumento nos leucócitos totais nos grupos exercitados (de 4,12 ± 0,17 x 10(6) para 8,69 ± 1,06 x 10(6) no grupo 5L, 9,5 ± 0,91 x 10(6) no grupo 15L, 12,56 ± 0,9 x 10(6) no grupo 5M e para 11,61 ± 0,6 x 10(6) no grupo 15M); aumento do número de macrófagos peritoneais após 15 minutos de exercício moderado (de 14,07 ± 0,57 x 10(6) para 20,9 ± 1,28 x 10(6)) e da capacidade fagocitária após 5 e 15 minutos de exercício leve de 74,8 ± 0,73 por cento para 79,8 ± 0,8 por cento e 83 por cento ± 0,44 por cento, respectivamente (p < 0,05). CONCLUSÕES: O exercício de curta duração promove aumento na capacidade fagocitária, fato esse de relevância para a reabilitação e esporte.

OBJECTIVE: To analyze the acute effects of short-duration exercise of different lengths and intensities on total leukocytes, peritoneal macrophage count and on the phagocytic capacity of peritoneal macrophages. METHOD: Five groups of Wistar rats were used (n= 30, n= 6 per group): one sedentary control group (C); two groups exercised for 5 minutes at low or moderate intensity (5L and 5M, respectively); and two groups exercised for 15 minutes at low or moderate intensity (15L and 15M, respectively). Low-intensity exercise was done without any load, while moderate-intensity was done with an additional load of 5 percent of the animal's body weight, attached to its back. The total leukocyte and monocyte counts were obtained under a microscope, and the readings were made with the Leucotron TP apparatus. The percentage phagocytosis was determined by counting in a Neubauer chamber, from the number of cells that phagocytized three or more particles of zymosan. Two-way ANOVA and Tukey tests were used, with p < 0.05. RESULTS: There was an increase in total leukocytes in the exercised groups (from 4.12 ± 0.17 x 10(6) to 8.69 ± 1.06 x 10(6) for 5L, 9.5 ± 0.91 x 10(6) for 15L, 12.56 ± 0.9 x 10(6) for 5M and 11.61 ± 0.6 x 10(6) for 15M), an increase in peritoneal macrophage count after 15 minutes of moderate exercise (from 14.07 ± 0.57 x 10(6) to 20.9 ± 1.28 x 10(6)) and an increase in phagocytic capacity after 5 and 15 minutes of light exercise (from 74.8 ± 0.73 percent to 79.8 ± 0.8 percent and 83 percent ± 0.44 percent, respectively) (p < 0.05). CONCLUSION: Short-duration exercise promotes increased phagocytic capacity. This is of importance for rehabilitation and sports.

Efeitos do fator de crescimento insulínico-i sobre o músculo esquelético e suas relações com o exercício físico / The insulin growth factor-i effects on skeletal muscle and the relationship with physical exercise

O fator de crescimento insulínico-I (IGF-I) e seus componentes exercem importante efeito sobre o crescimento somático e tecidual em muitas espécies. O IGF-I exerce um papel central na hipertrofia muscular associada ao exercício. Este polipeptídeo tem importante função no anabolismo tecidual, causando hipertrofia e hiperplasia tecidual em vários tipos de células, incluindo mioblastos do músculo esquelético e fibroblastos do tendão. As respostas do IGF-I ao exercício físico são dependentes da intensidade e duração do mesmo, podendo sua concentração estar reduzida em exercícios extenuantes (maratona) e aumentado em exercícios de curta duração e intensidade relativa (treinamento com pesos). Sendo assim, esse trabalho tem por objetivo revisar os principais efeitos do IGF-I sobre o músculo esquelético e suas relações com o exercício.

The Insulin growth factor-I (IGF-I) and it’s components exert important effect on somatic and tissue growth in many species. The IGF-I exerts a central role in muscle hypertrophy associated to exercise. It has an important function in tissue anabolism, causing tissue hypertrophy and hyperplasia in many cell types, including skeletal muscle myoblasts and tendon fibroblasts. IGF-I responses to physical exercise are dependant on it’s intensity and duration, so that, it’s levels may be reduced in exhausting exercises marathon) and enhanced in short duration and relative intensity exercises (weight training). This issue has the objective to review the main effects of IGF-I on skeletal muscle and the relationship with exercise.