Maria Paula Mota

The role of mitochondria in aging of skeletal muscle

Aging can be characterized as a time dependent decline of maximal functionality that affects tissues and organs of the whole body. Such is induced by the progressive loss of redundant components and leads to an increased susceptibility to disease and risk of death. Regarding the aging of skeletal muscle, it has been pointed out that mitochondria is a key factor behind the loss of redundancy and functionality, since this organelle has a major role in cellular homeostasis particularly at the level of the bioenergetic status. Decreased activities of the mitochondrial electron transport chain complexes and an increased release of reactive oxygen species from mitochondria are well documented with age; it is suggested that the mitochondrial loss of function results from the increased oxidative damage to proteins, lipids, and DNA of this organelle. However, it is important to be aware that the mitochondrial loss of function could also be a consequence, rather than a cause, of the cellular deterioration with age, which compromises mitochondrial biogenesis, mitochondrial protein turnover and autophagocytosis of damaged mitochondria. In this review several topics will be addressed regarding the age-related loss of skeletal muscle redundancy associated with mitochondrial dysfunction, emphasizing hypotheses for underlying mechanisms. In addition, we discuss some of the cellular mechanisms that can be pointed out as being responsible for the age-related mitochondrial dysfunction.

Effects of structured exercise and pharmacotherapy vs. pharmacotherapy for adults with depressive symptoms: A randomized clinical trial.

OBJECTIVE Physical exercise has been consistently documented as a complementary therapy in the treatment of depressive disorders. However, despite a higher prevalence among women compared to men, the trials developed in women are scarce. In addition, the optimal dosage of exercise capable of producing benefits that reduce depressive symptoms remains unclear. This clinical trial is designed to measure the effect of a structured physical exercise program as a complement to antidepressant medication in the treatment of women with depression. METHODS From July 2013 to May 2014, we implemented a randomized controlled trial (HAPPY BRAIN study). A total of 26 women (aged 50.16 ± 12.08) diagnosed with clinical depression were randomized either to a supervised aerobic exercise group (45-50 min/week three times a week for four months) plus pharmacotherapy (intervention group), or only antidepressant medication (control group). RESULTS The exercise group presented a decrease in BDI-II and DASS-21 total score scales. Relatively to DASS-21, it showed a significant decrease in anxiety and stress. The exercise group when compared to a control group showed improvement in relation to physical functioning parameters between baseline and post-intervention. Moreover, anthropometric parameters presented only significant differences between groups in fat mass percentage. Nonetheless, no differences were found between groups in weight, body mass index, waist circumference, and self-esteem. CONCLUSION Our results showed that supervised structured aerobic exercise training could be an effective adjuvant therapy for treating women with depression, reducing depressive symptomatology and improving physical fitness. A key factor of this improvement included strict control of exercise workload parameters and adjustment to each subjects capacity. In our study, due to the sample size there is an increase in the probability of type II errors.

Physical Inactivity is a Major Contributor to Ovariectomy-Induced Sarcopenia

Since the mechanism(s) underlying menopause-related sarcopenia remain unknown we aimed to investigate the role of physical inactivity in its etiology. Ovariectomized and sham-operated rats were allocated into 2 experimental groups: (1) sedentary-standard housing; and (2) exercise-housed with running wheel. After a 9-month experimental period, soleus muscle structure and biochemical properties were analyzed. No differences existed in muscle fibre size or ultrastructure between sedentary sham and ovariectomized animals housed in standard conditions. In the exercise groups, average daily running distance was 10-fold less in ovariectomized compared to sham-animals. Further, in exercised animals, soleus fibre size was smaller in ovariectomized compared to sham-animals. Nonetheless, compared to both sedentary groups, muscle fibre size was larger in the exercised ovariectomized animals. Our results indicate that ovariectomy-induced sarcopenia is not due to the loss of ovarian hormones per se, but is largely due to physical inactivity.

Influence of exercise order on muscle damage during moderate-intensity resistance exercise and recovery

This study aimed to investigate the role of exercise order on total number of repetitions and to evaluate the possible importance on muscle damage and on rating perceived exertion (RPE). Ten trained participants completed two sequences: sequence A (SEQA) was leg press (LP), leg extension (LE), leg curl (LC), bench press (BP), shoulder press (SP), and triceps extension (TE) and in sequence B (SEQB), the order of execution of the exercises was reversed. Highest creatine kinase (CK) concentrations were observed 24 hours following both sessions, but no differences were found at any time between them, revealing that muscle damage has occurred. There were significant differences between SEQA and SEQB in the total number of repetitions for TE, LE, and LC. Our results suggest that differences in total strength production when exercise order is changed must be explained by some other mechanisms besides muscle damage and RPE.

How can age and lifestyle variables affect DNA damage, repair capacity and endogenous biomarkers of oxidative stress?

Age-related DNA damage has been regarded as one of the possible explanations of aging, and these age-related changes have been associated with lifestyle variables. Considering this, the purpose of this study was to investigate how age and lifestyle may affect DNA damage, DNA repair capacity and endogenous biomarkers of oxidative stress. Sixty-one healthy men (40 to 89 yrs) were enrolled in this study. The results showed that DNA strand breaks (DNA SBs) and DNA repair capacity were greater in the older group (>=65 yrs) compared to the younger group (<65 yrs) (p<0.05). FPG-sensitive sites, total antioxidant capacity and lipid peroxidation (MDA) were not statistically different between groups. The correlation test showed that DNA damage variables were not correlated with any lifestyle variable excepting DNA SBs which was correlated with aerobic capacity (6MWT). DNA SBs and DNA repair were positively correlated with age. The multiple regression analysis revealed that the aerobic capacity (6MWT) and MDA were the predictors for the variation of DNA SBs (41.9%). In conclusion these results suggest that DNA SB damage increases with age but not FPG-sensitive sites. Moreover, base excision repair capacity increases with age without the increase of oxidative damage to DNA. The most predictable variables of DNA SBs were the aerobic capacity and MDA.

Age-related increases in human lymphocyte DNA damage: is there a role of aerobic fitness?

Oxidative stress has been advanced as one of the major causes of damage to DNA and other macromolecules. Although physical exercise may also increase oxidative stress, an important role has been recognized for regular exercise in improving the overall functionality of the body, as indicated by an increase in maximal aerobic uptake ( V˙ O2max), and in resistance to cell damage. The aims of this study were 1) to evaluate the association between DNA damage in human lymphocytes and age and 2) to evaluate the association between DNA damage in human lymphocytes and V˙ O2max. The sample was composed of 36 healthy and nonsmoking males, aged from 20 to 84 years. V˙ O2max was evaluated through the Bruce protocol with direct measurement of oxygen consumption. The comet assay was used to evaluate the DNA damage, strand breaks and formamidopyrimidine DNA glycosylase (FPG)‐sensitive sites. We found a positive correlation of age with DNA strand breaks but not with FPG‐sensitive sites. V˙ O2max was significantly inversely related with DNA strand breaks, but this relation disappeared when adjusted for age. A significantly positive relation between V˙ O2max and FPG‐sensitive sites was verified. In conclusion, our results showed that younger subjects have lower DNA strand breaks and higher V˙ O2max compared with older subjects and FPG‐sensitive sites are positively related with V˙ O2max, probably as transient damage due to the acute effects of daily physical activity. Copyright

Portuguese adults' physical activity during different periods of the year

Abstract This study aims to describe the daily physical activity (PA) of a sample of adults over the course of 1 year and to examine if there are any changes in achieving PA recommendations when assessed at different periods of the year. Participants, 257 women (age: 58.99±18.93 years, BMI: 26.75±4.57 kg m−2) and 178 men (age: 49.22±20.39 years, BMI: 26.81±3.51 kg m−2), wore an accelerometer 4–7 days. Periods of data collection were defined as T1 (September to December), T2 (January to April) and T3 (May to July). From T1 and T2, men from 20 to 39 years significantly increased values of daily average ct.min−1 (U=506, p=0.012), due to an increase in moderate-to-vigorous PA by 15.96 min (U=455, p=0.003). Achievement of the two PA recommendations varied throughout the year and among the gender/age groups. Results from this study showed that women generally maintain their level of PA throughout the year, whereas men show some variation, and that there are periods of the year when individuals are more likely to be involved in PA, or perform lower-intensity activities, especially older age groups. Also, recommendations of minimum PA are not accomplished in a constant way throughout the year. PA interventions should be conducted while being mindful of the time of year in which they will take place in order to help maintain a consistent PA level throughout the year to ensure health benefits from PA.

Lifelong Sedentary Behaviour and Femur Structure

The aim of the present study was to analyze the lifelong differences of femur structure in sedentary and physically active animal models. Thirty male C57BL/6 mice, 2 months old, were either: i) housed in cages with running wheel (AA; n=10), ii) housed in cages without running wheel (AS; n=10), iii) or sacrificed without intervention (Y; n=10). AA and AS animals were sacrificed after 23 months of housing. Right femur structure was analyzed in all animals by histomorphometry. Significant differences in several microarchitectural parameters of cancellous and cortical bone were identified between Y mice and both groups of aged mice, as well as between AA and AS groups. Lifelong physically active mice had significantly higher cancellous bone surface (Cn.BS) and trabecular number (Tb.N) and decreased trabecular separation (Tb.Sp) at both epiphyses when compared to AS animals. No differences were observed between Y and AA groups regarding osteocyte number (N.Ot) despite its significant reduction in AS animals, suggesting that age alone was not a cause for decreases in N.Ot. Our results suggest that the reduced bone quality observed in the elderly is not only a consequence of age but also of lack of physical activity since sedentary behaviour significantly aggravated the degenerative age-related bone differences.

Impact of physical exercise on catechol-O-methyltransferase activity in depressive patients: A preliminary communication

BACKGROUND Catechol-O-methyltransferase (COMT) is a catabolic enzyme involved in the degradation of bioactive molecules including the neurotransmitters epinephrine, norepinephrine, and dopamine. Higher COMT activity in depressive patients in comparison to non-depressed individuals has been reported. The effect of aerobic exercise on depressive patients has been studied and a number of researchers and clinicians believe it to be effective in the treatment of depression and to be involved in several molecular underlying mechanisms. However, the effect of physical exercise on this enzyme activity is unknown, and it remains to be elucidated if chronic exercise changes COMT activity. This randomized control trial evaluates the effects of chronic exercise on peripheral COMT (S-COMT) activity in women with depressive disorder. METHODS Fourteen women (aged: 51.4±10.5 years) diagnosed with depression (according to International Classification of Diseases-10) were randomized to one of two groups: pharmacotherapy plus physical exercise (n=7) or only pharmacotherapy (n=7). The aerobic exercise program was supervised, lasting between 45-50min/session, three times/week for 16 weeks. Erythrocyte soluble COMT were assessed prior to and after the exercise program. RESULTS Exercise group when compared to a control group presented a significant decrease (p=0.02, r=-0.535) in S-COMT activity between baseline and post-intervention. LIMITATIONS These data are preliminary outcomes from a small sample and should be replicated. CONCLUSIONS Chronic exercise therapy combined with pharmacotherapy leads to significant decrease in S-COMT activity. Our results provide evidence that exercise interferes with S-COMT activity, a molecular mechanism involved in depression.

Exercise as an Essential Therapeutic Tool in Mental Health: Closing the Gap From Research to Practice, A Portuguese Perspective

1. Centre of Research, Sports Sciences, Health and Human Development. Universidade de Trás-os-Montes e Alto Douro. Vila Real. Portugal. 2. School of Psychiatry. University of New South Wales. Sydney. Australia. 3. The Black Dog Institute. University of New South Wales. Prince of Wales Hospital. Wales. Australia. 4. Post-graduation Program in Health and Human Development. Unilasalle. Canoas. Brazil. 5. Hospital de Clínicas de Porto Alegre. Porto Alegre. Brazil. 6. Instituto de Engenharia de Sistemas e Computadores, Tecnologia e Ciência. Universidade de Trás-os-Montes e Alto Douro. Vila Real. Portugal.  Autor correspondente: Lara Carneiro. larafcarneiro@gmail.com Recebido: 05 de novembro de 2016 Aceite: 10 de abril de 2017 | Copyright