Gustavo Casimiro-Lopes

Temporal evaluation of body composition, glucose homeostasis and lipid profile of male rats programmed by maternal protein restriction during lactation.

Neonatal protein restriction causes lower body weight and hormonal dysfunctions in 6 months-old rats. In this model, we studied the body composition, glycogen content, serum lipid, serum protein, and hormones related to glucose homeostasis in the offspring during development. At birth, lactating rats were divided into: control dams - fed a normal diet (23% protein) and protein restricted dams - fed a diet with 8% protein. After weaning, pups received normal diet. Offspring were killed at 21, 90, and 180 days-old. Protein restricted offspring showed lower visceral fat (90th day: 14%; 180th day: 19%) and lower total fat (90th day: 16%; 180th day: 14%) that explain their lower body weight. They presented lower glycemia (180th day: 17%), lower insulinemia (21st day: 63%; 180th day: 24%), higher adiponectinemia (21st day: 169%), higher liver glycogen (21st day: 104%), and higher muscle glycogen (180th day: 106%), suggesting a higher insulin sensitivity. The higher serum corticosterone (50%), higher adrenal total catecholamines content (98%) as well as in vitro catecholamine secretion (26%) of adult protein restricted offspring, suggest a programming stimulatory effect upon adrenal gland. They also presented several biochemical changes, such as lower serum total protein, albumin and globulin (21st day: 17, 21, 12%, respectively), higher LDL-c (21st day: 69%), lower triglycerides (21st day: 42%; 90th day: 39%), and lower total cholesterol (180th day: 16%). Thus, maternal protein restriction during lactation induces an energy-protein malnutrition, characterized by an impairment of the pups protein anabolism and, after weaning, the lower adiposity suggests lower lipogenesis and higher lipolytic activity, probably caused by catecholamine and glucocorticoid action.

Maximum acute exercise tolerance in hyperthyroid and hypothyroid rats subjected to forced swimming.

Thyroid dysfunction can compromise physical capacity. Here, we analyze the effects of hyperthyroidism and hypothyroidism on maximum swim time in rats subjected to acute forced swimming, as an indicator of anaerobic capacity. Animals were forced to swim against a load (5% of body weight) attached to the tail and were killed 48 hours after the last test. Hyperthyroid rats were treated with thyroxine (50 mug/100 g body weight, i. p. for 7 days). The hypothyroid group received 0.03% methimazole in the drinking water for 4 weeks. Thyroid state was confirmed by alterations in serum thyroid-stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), and liver mitochondrial glycerol phosphate dehydrogenase (mGPD) activity. Hyperthyroid rats presented significantly lower visceral fat mass (VFM) and higher food intake (p<0.05) with unchanged body weight. Maximum swim time (MST), glycogen content (skeletal muscle and liver), and leptin levels were lower while corticosterone was higher (p<0.05). In hypothyroid rats body weight was lower (p<0.05), without changes in VFM. Tested at 7-day intervals, MST was lower for tests 2, 3, and 4 (p<0.05). Muscle glycogen was higher in extensor digitorum longus (EDL) and soleus (p<0.05), without changes in liver. Serum corticosterone was lower, while leptin was higher (p<0.05). These results suggest that in hyperthyroid and hypothyroid rats, thyroid hormones together with corticosterone and/or leptin may impair exercise capacity differently through its known effects on glycogen metabolism.

High Intensity Interval Training (HIIT) Induces Specific Changes in Respiration and Electron Leakage in the Mitochondria of Different Rat Skeletal Muscles

High intensity interval training (HIIT) is characterized by vigorous exercise with short rest intervals. Hydrogen peroxide (H2O2) plays a key role in muscle adaptation. This study aimed to evaluate whether HIIT promotes similar H2O2 formation via O2 consumption (electron leakage) in three skeletal muscles with different twitch characteristics. Rats were assigned to two groups: sedentary (n=10) and HIIT (n=10, swimming training). We collected the tibialis anterior (TA-fast), gastrocnemius (GAST-fast/slow) and soleus (SOL-slow) muscles. The fibers were analyzed for mitochondrial respiration, H2O2 production and citrate synthase (CS) activity. A multi-substrate (glycerol phosphate (G3P), pyruvate, malate, glutamate and succinate) approach was used to analyze the mitochondria in permeabilized fibers. Compared to the control group, oxygen flow coupled to ATP synthesis, complex I and complex II was higher in the TA of the HIIT group by 1.5-, 3.0- and 2.7-fold, respectively. In contrast, oxygen consumed by mitochondrial glycerol phosphate dehydrogenase (mGPdH) was 30% lower. Surprisingly, the oxygen flow coupled to ATP synthesis was 42% lower after HIIT in the SOL. Moreover, oxygen flow coupled to ATP synthesis and complex II was higher by 1.4- and 2.7-fold in the GAST of the HIIT group. After HIIT, CS activity increased 1.3-fold in the TA, and H2O2 production was 1.3-fold higher in the TA at sites containing mGPdH. No significant differences in H2O2 production were detected in the SOL. Surprisingly, HIIT increased H2O2 production in the GAST via complex II, phosphorylation, oligomycin and antimycin by 1.6-, 1.8-, 2.2-, and 2.2-fold, respectively. Electron leakage was 3.3-fold higher in the TA with G3P and 1.8-fold higher in the GAST with multiple substrates. Unexpectedly, the HIIT protocol induced different respiration and electron leakage responses in different types of muscle.

Associations of n-6 and n-3 polyunsaturated fatty acids and tocopherols with proxies of membrane stability and subcutaneous fat sites in male elite swimmers

We hypothesize that membrane stability of elite swimmers adapted to chronic intense training is dependent on polyunsaturated fatty acids (PUFAs) and tocopherols in blood pools and that the composition of PUFA in plasma nonesterified fatty acids (NEFAs) might be associated with specific subcutaneous fat sites. Our aims were to investigate in male elite swimmers the associations of n-6 and n-3 PUFA and alpha- and gamma-tocopherols with proxies of membrane stability (phase angle and erythrocyte osmotic fragility) and of PUFA in plasma NEFA with specific skinfolds. Brazilian male elite swimmers (n = 20) under regular training for an average of 4.1 h/d and 6.1 d/wk took part in the study. Blood samples were obtained once after 18-hour rest and an overnight fast. Fatty acids were determined in plasma NEFA and erythrocytes by gas chromatolography and tocopherols were determined in plasma and erythrocytes by high-performance liquid chromatography. The status of PUFA was assessed as mean melting point, PUFA index [(Sigman-6 + Sigman-3) / (Sigman-7 + Sigman-9)] and docosahexaenoic acid indices (22:5n-6/22:4n-6 and 22:6n-3/22:5n-6 ratios) calculated from erythrocyte fatty acids. Phase angle was associated with an index of docosahexaenoic acid inadequacy (22:5n-6/22:4n-6; r = -0.53, P = .019) and with 22:5n-3 in erythrocytes (r = 0.51, P = .024), and erythrocyte osmotic fragility was associated with plasma alpha-tocopherol (r = -0.51, P = .05), which is a biomarker of vitamin E status. Plasma NEFAs 18:3n-3 and 20:4n-6 were positively associated with skinfolds of the trunk and arms (r = 0.49-0.59, P = .011-.043). The data presented indicate that n-3 PUFA and vitamin E states possibly improve membrane stability in elite swimmers and that the extent of specific anatomic sites of subcutaneous adipose tissue in the upper body might contribute to the composition of NEFA in the resting state.

Effects of running wheel training on adult obese rats programmed by maternal prolactin inhibition

The inhibition of maternal prolactin production in late lactation leads to metabolic syndrome and hypothyroidism in adult offspring. Physical training is a therapeutic strategy that could prevent or reverse this condition. We evaluated the effects of a short-duration low-intensity running wheel training program on the metabolic and hormonal alterations in rats. Lactating Wistar rats were treated with bromocriptine (Bro, 1 mg twice a day) or saline on days 19, 20, and 21 of lactation, and the training of offspring began at 35 days of age. Offspring were divided into sedentary and trained controls (C-Sed and C-Ex) and sedentary and trained Bro-treated rats (Bro-Sed and Bro-Ex). Chronic exercise delayed the onset of weight gain in Bro-Ex offspring, and the food intake did not change during the experimental period. At 180 days, visceral fat mass was higher (+46%) in the Bro-Sed offspring than in C-Sed and Bro-Ex rats. As expected, running capacity was higher in trained animals. Most parameters observed in the Bro-Sed offspring were consistent with hypothyroidism and metabolic syndrome and were reversed in the Bro-Ex group. Chronic exercise did not influence the muscle glycogen in the C-Ex group; however, liver glycogen was higher (+30%) in C-Ex group and was unchanged in both Bro offspring groups. Bro-Ex animals had higher plasma lactate dehydrogenase levels, indicating skeletal muscle damage and intolerance of the training program. Low-intensity chronic training is able to normalize many clinical aspects in Bro animals; however, these animals might have had a lower threshold for exercise adaptation than the control rats.

Maternal prolactin inhibition during lactation affects physical performance evaluated by acute exhaustive swimming exercise in adult rat offspring.

Maternal prolactin inhibition at the end of lactation programs for metabolic syndrome and hypothyroidism in adult offspring, which could negatively affect exercise performance. We evaluated the effects of maternal hypoprolactinemia in late lactation on physical performance in adult progeny. Lactating Wistar rats were treated with bromocriptine (BRO, 1 mg per day) or saline on days 19, 20, and 21 of lactation and offspring were followed until 180 days old. Physical performance was recorded in untrained rats at 90 and 180 days by an acute exhaustive swimming test (exercise group-Ex). At day 90, BRO offspring showed higher visceral fat mass, higher plasma thiobarbituric acid reactive substances, lower total antioxidant capacity, higher liver glycogen, lower glycemia, and normal insulinemia. Although thyroid hormones (TH) levels were unchanged, mitochondrial glycerol phosphate dehydrogenase (mGPD) activity was lower in muscle and in brown adipose tissue (BAT). At this age, BRO-Ex offspring showed higher exercise capacity, lower blood lactate, higher serum T3, and higher muscle and BAT mGPD activities. At day 180, BRO offspring showed central obesity, hypothyroidism, insulin resistance, and lower EDL (extensor digitorum longus) muscle glycogen with unaltered plasma oxidative stress markers. This group showed no alteration of exercise capacity or blood lactate. After exercise, EDL and liver glycogen were lower, while T3 levels, BAT and muscle mGPD activities were normalized. Liver glycogen seem to be related with higher exercise capacity in younger BRO offspring, while the loss of this temporary advantage maybe related to the hypothyroidism and insulin resistance developed with age.

Methodological Agreement between Body-Composition Methods in Young Soccer Players Stratified by Zinc Plasma Levels

Es factible pensar que la evaluacion de la composicion corporal puede estar influenciada por el estado de maduracion y los niveles plasmaticos de zinc, especialmente en atletas jovenes, que regularmente realizan un alto volumen de entrenamiento fisico. Por tanto, es importante aclarar el impacto de estos factores en la evaluacion de la composicion corporal de los atletas, ya que errores en su analisis pueden conducir al desarrollo de una equivocada prescripcion de entrenamiento, ademas de una dieta determinada, y por lo tanto afectar el rendimiento deportivo. El objetivo de esta investigacion consistio en: (1) comparar los diferentes metodos de evaluacion de la composicion corporal en futbolistas jovenes estratificados por los niveles plasmaticos de zinc; (2) comparar los dos metodos de referencia utilizando el espesor de los pliegues cutaneos en ninos (ecuaciones de Slaughter y Lohman), teniendo en cuenta el nivel de maduracion. En este estudio transversal, cincuenta futbolistas jovenes (13,3±0,7 anos) fueron sometidos a un perfil bioquimico de sangre, bioimpedancia electrica (BIA), absorciometria de rayos X de energia dual (DXA), medidas antropometricas (masa corporal, estatura y pliegues cutaneos de espesor (ST)) y radiografia de mano-muneca. La evaluacion de la composicion corporal se realizo por: DXA, ST (ecuaciones Lohman y Slaughter) y BIA (ecuacion Houtkooper). El nivel de zinc identifico dos grupos: deportistas normozincemicos e hipozincemicos, determinados por un punto de corte de 11,0 mmol/L. Se observo una diferencia significativa en los datos descriptivos de todos los participantes despues de la estratificacion del estado de zinc solo para la concentracion de zinc en plasma; se observaron correlaciones significativas entre los metodos de evaluacion (porcentaje de grasa: r= 0,34 a 0,98 y p <0,001 a 0,013; masa libre de grasa: r= desde 0,95 hasta 0,9998 y p <0,001), y disminuyeron las correlaciones al estar involucrada la impedancia electrica. Los resultados a traves de los metodos Bland y Altman mostraron un acuerdo mas cercano al comparar DXA y ST. El metodo ST fue mejor que el BIA para evaluar la composicion corporal (en los jugadores jovenes de futbol), cuando no estaban disponibles los escaneos DXA. La comparacion de los modelos basados en ST mostro que la mejor asociacion de valores DXA se obtuvieron para la ecuacion Slaughter, seguidos por la ecuacion Lohman utilizando la edad osea en lugar de la edad cronologica. Los niveles de zinc en plasma parecen no influir en la evaluacion de la composicion corporal, lo que amerita mas estudios.

Acute high-intensity exercise test in soccer athletes affects salivary biochemical markers

Abstract Saliva has been reported as a potential biological fluid for biochemical monitoring. This study investigated salivary markers of exercise intensity, oral mucosal immunity, and redox homeostasis in soccer athletes subjected to an acute high-intensity interval exercise (HIIE) protocol characterised by a repeated sprint ability test. Thirty-two professional soccer athletes were recruited and saliva aliquots were collected at rest and immediately after HIIE protocol. When compared with pre-test values we observed that HIIE protocol induced moderate changes for total protein (p = .015; effect size (ES) = 0.51; smallest worthwhile change (SWC)factor = 5.7) and for cortisol levels (p < .0001; ES = 0.49; SWCfactor = 3.9). Lactate levels showed very large changes (p < .000; ES = 1.35; SWCfactor = 10.8), while Ig-A alterations were considered unclear. Besides, transferrin changes were trivial and maintained its levels at rest and after HIIE below the proposed threshold of 0.5 mg/dL. Regarding redox homeostasis we observed unclear effects for TBARs, MDA, GSH, GSSG, CAT, and SOD while uric acid showed large decreases (p = .005; ES = 0.80; SWCfactor = −5.4). HIIE protocol as a physical test conducted in soccer athletes increased salivary concentration of exercise intensity markers, such as lactate, total protein, and cortisol, but did not affect Ig-A levels. Redox homeostasis in saliva seems to be more related with uric acid levels as a possible key factor TBARs homeostasis.

Biological Maturation Assessment Methods in Adolescent Soccer Players Considering Zinc Status

The purpose of this study was to compare different methods of maturity evaluation and their relation with performance-related physical and anthropometric variables in young soccer players, with different plasma zinc status. A total of 53 healthy male young soccer players (age: 13±1 years; body mass: 48±10 kg; stature: 160±10 cm) participated in this study. Variables from physical fitness (stature, ST; fat-free mass, FFM; handgrip strength in the dominant hand, DHS), testosterone and zinc plasma concentration were measured. Biological maturity was evaluated by sexual maturity (development of: pubic hair, PH; genitals, GD; axillary hair; AH), bone maturity (TW3 method; BA), and testosterone plasma concentration methods. We observed that: (i) the frequency of hypozincemics and normozincemics children stratified by BA-CA, PH and GD were similar in each category; (ii) the BA allowed the identification of differences between the three categories, in at least two performance-related variables (FFM and DHS, p<0.0001); (iii) the AH method was able to discriminate only for DHS (p<0.0001); and (iv) the testosterone method was not able to identify differences between the four maturation categories with regard to ST, FFM, and DHS. Results suggested that Zinc deficiency did not influence the results obtained for the maturation categories defined by the different assessment methods. The assessment of biological maturation by BA seems to be the most effective for the stratification of performance-related and anthropometric variables in young soccer players. Nevertheless, the AH method should also be considered as a fair option to be used in field studies and practice.