Effect of Physical Activity on Cognitive Development: Protocol for a 15-Year Longitudinal Follow-Up Study

Development and validation of brain-derived neurotrophic factor measurement in human urine samples as a non-invasive effect biomarker

Background

Brain-derived neurotrophic factor (BDNF), a neurotrophic growth factor mainly expressed in the brain, has been proposed as a potential effect biomarker; that is, as a measurable biomarker whose values could be associated with several diseases, including neurological impairments. The European Human Biomonitoring Initiative (HBM4EU) has also recognized effect biomarkers as a useful tool for establishing link between exposure to environmental pollutants and human health. Despite the well-establish protocol for measuring serum BDNF, there is a need to validate its assessment in urine, a non-invasive sample that can be easily repeated over time. The aim of this study was to develop, standardize and validate a methodology to quantify BDNF protein levels in urine samples before its implementation in biomonitoring studies.

Methods

Different experimental conditions and non-competitive commercial enzyme-linked immunosorbent assay (ELISA) kits were tested to determine the optimal analytical procedure, trying to minimize the shortcomings of ELISA kits. The fine-tune protocol was validated in a pilot study using both upon awakening (n = 150) and prior to sleeping (n = 106) urine samples from the same Spanish adolescent males in a well-characterized study population (the Spanish INMA-Granada cohort).

Results

The best results were obtained in 0.6 ml of urine after the acidification and extraction (pre-concentration) of samples. The highest reproducibility was obtained with the ELISA kit from Raybiotech. Urinary BDNF concentrations of adolescent males were within the previously reported range (morning = 0.047-6.801 ng/ml and night = 0.047-7.404 ng/ml). Urinary BDNF levels in the awakening and pre-sleep samples did not follow a normal distribution and were not correlated.

Conclusion

The developed methodology offers good sensitivity and reproducibility. Having reliable markers in urine may facilitate both diagnosis and monitoring possible diseases (and treatment). Further studies are needed to implement urinary BDNF in biomonitoring studies to further elucidate its usefulness and biological significance for neurological impairments.

Association between tennis training experience and executive function in children aged 8–12

Cognitively engaging activities have been shown to facilitate the improvement of executive functions in children. However, a limited number of studies have investigated whether the relationship between dose parameters of physical activities and executive functions, and heterogeneity exists. In the present study, we aim to explore the association between tennis training experience and executive functions in children. Sixty children between the ages of 8 and 12 were recruited in this study and were allocated to the short-term (ST) group (<12 months, n = 30) and the long-term (LT) group (more than 12 months, n = 30). The abilities of inhibitory control, cognitive flexibility, and working memory were measured by the Stop-signal task, Switching task, and N-back task, respectively. There was no significant group difference in either the accuracy or reaction time of the Stop-signal task. No significant difference between the groups' accuracy in the Switching task was observed. However, the LT group presented a shorter reaction time than the ST group (731.69 ± 149.23 ms vs. 857.15 ± 157.99 ms, P < 0.01) in the Switching task. Additionally, training experience was positively associated with the reaction time of the Switching task. As for the N-back task, in comparison with the LT group, the ST group showed a longer reaction time (711.37 ± 168.14 ms vs. 164.75 ± 635.88 ms, P < 0.05). Moreover, training experience was also positively associated with the reaction time of the N-back task. But there was no significant group difference in the accuracy of the N-back task. In conclusion, children trained for over 1 year have better performance in cognitive flexibility and working memory than those trained in <1 year; thus, tennis experience is positively associated with executive functions.

Field-based physical fitness assessment in preschool children: A scoping review

Physical fitness, which can be measured using various health- and skill-related components, is an important indicator of child development and health status. This study undertakes a scoping review on physical fitness assessment methods in preschool children to summarize the most widely used field-based physical fitness batteries and specific test items for preschool children. A search of the literature in English was undertaken using two major electronics databases, which yielded 76 literatures that met the inclusion and exclusion criteria. These literatures took the quantitative indicators of physical fitness as the outcome variables in 3-6-year-old children. This review found that of these 76 literatures analyzed, 71.1% came from Europe and 89.5% were published after 2010. The results showed six physical fitness test batteries, with the assessing FITness in PREschoolers (PREFIT) battery is the most widely used, and specific test items such as body mass index (BMI), standing long jump, handgrip, one-leg stance, sit and reach, 20 m shuttle run test (SRT)-PREFIT, and 4 × 10 m SRT are widely used in corresponding components. Therefore, we recommend that an international standard for some specific test items should be developed for preschool children to facilitate more widespread adoption and promote physical fitness assessment for preschool children.

(Neuro) Peptides, Physical Activity, and Cognition

Regular physical activity (PA) improves cognitive functions, prevents brain atrophy, and delays the onset of cognitive decline, dementia, and Alzheimer’s disease. Presently, there are no specific recommendations for PA producing positive effects on brain health and little is known on its mediators. PA affects production and release of several peptides secreted from peripheral and central tissues, targeting receptors located in the central nervous system (CNS). This review will provide a summary of the current knowledge on the association between PA and cognition with a focus on the role of (neuro)peptides. For the review we define peptides as molecules with less than 100 amino acids and exclude myokines. Tachykinins, somatostatin, and opioid peptides were excluded from this review since they were not affected by PA. There is evidence suggesting that PA increases peripheral insulin growth factor 1 (IGF-1) levels and elevated serum IGF-1 levels are associated with improved cognitive performance. It is therefore likely that IGF-1 plays a role in PA induced improvement of cognition. Other neuropeptides such as neuropeptide Y (NPY), ghrelin, galanin, and vasoactive intestinal peptide (VIP) could mediate the beneficial effects of PA on cognition, but the current literature regarding these (neuro)peptides is limited.

Shaping the adult brain with exercise during development: Emerging evidence and knowledge gaps

Exercise is known to produce a myriad of positive effects on the brain, including increased glia, neurons, blood vessels, white matter and dendritic complexity. Such effects are associated with enhanced cognition and stress resilience in humans and animal models. As such, exercise represents a positive experience with tremendous potential to influence brain development and shape an adult brain capable of responding to life's challenges. Although substantial evidence attests to the benefits of exercise for cognition in children and adolescents, the vast majority of existing studies examine acute effects. Nonetheless, there is emerging evidence indicating that exercise during development has positive cognitive and neural effects that last to adulthood. There is, therefore, a compelling need for studies designed to determine the extent to which plasticity driven by developmental exercise translates into enhanced brain health and function in adulthood and the underlying mechanisms. Such studies are particularly important given that modern Western society is increasingly characterized by sedentary behavior, and we know little about how this impacts the brain's developmental trajectory. This review synthesizes current literature and outlines significant knowledge gaps that must be filled in order to elucidate what exercise (or lack of exercise) during development contributes to the health and function of the adult brain.

ACTN3 is associated with children's physical fitness in Han Chinese

The ACTN3 gene locates on 11q13-q14 and encodes the α-actinin-3 protein, which is only expressed in human skeletal muscle and influenced muscle function and metabolism. The previous studies reported that SNP rs1815739 is associated with elite power athletes' performance. In this study, we investigated the association between five SNPs within the ACTN3 gene and Chinese children physical fitness. We recruited 2244 Han Chinese children participants, and measured their 25-m run, stand broad jump, 10-m shuttle run, handgrip, BMI (calculated by weight and height) data. SNPs rs1671064, rs2275998, rs2290463, rs10791881, and rs1815739 of ACTN3 gene were genotyped and analyzed in five physical fitness data. QTL analysis on genotype and physical fitness data was carried out in all samples. Furthermore, a dichotomous division of samples into an overweight group (543) and a normal group (1701) was used for an association study of overweight. In the QTL analysis, we found rs2290463 was significantly associated with stand broad jump (corrected P value = 0.009, beta = 2.692). After added age and gender as covariates in the regression test, the association became more significant (P value = 5.80 × 10^- 5, corrected P value = 4.06 × 10^- 4); when we used BMI as a covariate, the association still existed (P value = 4.65 × 10^- 4, corrected P value = 0.001). In the association study of overweight, rs2275998 was found to be significant (OR, 95% CI = 0.733 [0.6-0.895]; P_allele = 0.011, P_genotype = 0.024) after the Bonferroni correction, and the association did not change much after a further correction for gender, age, and stand broad jump performance. Our results showed that common variants in ACTN3 are significantly associated with both stand broad jump performance and overweight in Han Chinese children.

Preschoolers' Technology-Assessed Physical Activity and Cognitive Function: A Cross-Sectional Study

Early childhood is a critical period for development of cognitive function, but research on the association between physical activity and cognitive function in preschool children is limited and inconclusive. This study aimed to examine the association between technology-assessed physical activity and cognitive function in preschool children. A cross-sectional analysis of baseline data from the Physical Activity and Cognitive Development Study was conducted in Shanghai, China. Physical activity was measured with accelerometers for 7 consecutive days, and cognitive functions were assessed using the Chinese version of Wechsler Young Children Scale of Intelligence (C-WYCSI). Linear regression analyses were used to assess the association between physical activity and cognitive function. A total of 260 preschool children (boys, 144; girls, 116; mean age: 57.2 ± 5.4 months) were included in analyses for this study. After adjusting for confounding factors, we found that Verbal Intelligence Quotient, Performance Intelligence Quotient, and Full Intelligence Quotient were significantly correlated with light physical activity, not moderate to vigorous physical activity, in boys. Standardized coefficients were 0.211, 0.218, and 0.242 (all p < 0.05) in three different models, respectively. However, the correlation between physical activity and cognitive functions were not significant in girls (p > 0.05). These findings suggest that cognitive function is apparently associated with light physical activity in boys. Further studies are required to clarify the sex-specific effect on physical activity and cognitive functions.