Gestational diabetes mellitus (GDM) is defined as any degree of glucose intolerance that is diagnosed for the first time during pregnancy. The objective of this study is to know the glucose tolerance status after 15 years of pregnancy in patients diagnosed with gestational diabetes and to assess the long-term effect of GDM on the circulating miRNA profile of these women. To answer these, 30 randomly selected women diagnosed with GDM during 2005–2006 were included in the study, and glucose tolerance was measured using the National Diabetes Data Group criteria. Additionally, four miRNAs (hsa-miR-1-3p, hsa-miR-24-3p, hsa-miR-329-3p, hsa-miR-543) were selected for their analysis in the plasma of women 15 years after the diagnosis of GDM. In our study we discovered that, fifteen years after the diagnosis of GDM, 50% of women have some degree of glucose intolerance directly related to body weight and body mass index during pregnancy. Dysglycemic women also showed a significantly increased level of circulating hsa-miR-24-3p. Thus, we can conclude that initial weight and BMI, together with circulating expression levels of hsa-miR-24-3p, could be good predictors of the future development of dysglycemia in women with a previous diagnosis of GDM.

Background: Regular exercise has been described to modify both the diversity and the relative abundance of certain bacterial taxa. To our knowledge, the effect of a cycling stage race, which entails extreme physiological and metabolic demands, on the gut microbiota composition and its metabolic activity has not been analysed. Objective: The aim of this cohort study was to analyse the dynamics of faecal microbiota composition and short-chain fatty acids (SCFAs) content of professional cyclists over a Grand Tour and their relationship with performance and dietary intake. Methods: 16 professional cyclists competing in La Vuelta 2019 were recruited. Faecal samples were collected at four time points: the day before the first stage (A); after 9 stages (B); after 15 stages (C); and on the last stage (D). Faecal microbiota populations and SCFA content were analysed using 16S rRNA sequencing and gas chromatography, respectively. A principal component analysis (PCA) followed by Generalised Estimating Equation (GEE) models were carried out to explore the dynamics of microbiota and SCFAs and their relationship with performance. Results: Bifidobacteriaceae, Coriobacteriaceae, Erysipelotrichaceae, and Sutterellaceae dynamics showed a strong final performance predictive value (r = 0.83, ranking, and r = 0.81, accumulated time). Positive correlations were observed between Coriobacteriaceae with acetate (r = 0.530) and isovalerate (r = 0.664) and between Bifidobacteriaceae with isobutyrate (r = 0.682). No relationship was observed between SCFAs and performance. The abundance of Erysipelotrichaceae at the beginning of La Vuelta was directly related to the previous intake of complex-carbohydrate-rich foods (r = 0.956), while during the competition, the abundance of Bifidobacteriaceae was negatively affected by the intake of simple carbohydrates from supplements (r = −0.650). Conclusions: An ecological perspective represents more realistically the relationship between gut microbiota composition and performance compared to single-taxon approaches. The composition and periodisation of diet and supplementation during a Grand Tour, particularly carbohydrates, could be designed to modulate gut microbiota composition to allow better performance.

Objective: The aim of this study was to analyse the dynamics of faecal microbiota composition and short-chain fatty acids (SCFAs) content of professional cyclists over a Grand Tour, and their relationship with performance and dietary intake. Design: 16 professional cyclists competing in La Vuelta 2019 were recruited. Faecal samples were collected at four time points: The day before the first stage (A); After 9 stages (B); After 15 stages (C); On the last stage (D). Faecal microbiota populations and SCFAs content were analysed using 16S rRNA sequencing and gas chromatography, respectively. Results: A principal component analysis (PCA) followed by Generalized Estimating Equation (GEE) models were carried out to explore the dynamics of microbiota and SCFAs, and its relationship with performance. Bifidobacteriaceae, Coriobacteriaceae, Erysipelotrichaceae , and Sutterellaceae dynamics showed a strong final performance predictive value (R ² =0.83, ranking and R ² =0.81, accumulated time). Positive correlations were observed between Coriobacteriaceae and acetate and isovalerate and Bifidobacteriaceae and isobutyrate. No relationship was observed between SCFAs and performance. The abundance of Bifidobacteriaceae, Coriobacteriaceae , and Erysipelotrichaceae at the beginning of La Vuelta was directly related to the previous intake of a complex-carbohydrate-rich food, potatoes, while during the competition the abundance of Bifidobacteriaceae was negatively affected by the intake of simple carbohydrates from supplements. Conclusion: An ecological perspective represents more realistically the relationship between gut microbiota composition and performance, compared to single-taxon approaches. The composition and periodisation of diet and supplementation during a Grand Tour, particularly carbohydrates, could be designed to modulate gut microbiota composition that allow better performance. KEY MESSAGES: What is already known on this topic: Gut microbiota composition and metabolic activity change in response to acute exercise and training and can directly influence physical performance. However, the effect of a cycling stage race, which entails repeated and continuous days of competition, with extreme physiological and metabolic demands, has not been analysed. What this study adds: Our results show that microbiota dynamics during a Grand Tour involve many taxa and allow performance prediction. Those dynamics are related to dietary intake, both prior to and during competition. How this study might affect research, practice or policy: Our results demonstrate that limiting the relationship between gut microbiota composition and sports performance to a single taxon or metabolite is a reductionist approach that does not reflect the complexity of the microbial ecosystem. It may help to optimize the composition and periodisation of diet and supplementation based on gut microbiota modulation to optimize performance.

SUMMARY: It remains unclear whether the adaptive response to different exercise models is mediated by EV miRNAs released from skeletal muscle and their functional metabolic role. We sequenced miRNA-loaded plasma EVs obtained from resting mice after 4-weeks endurance or resistance training. Resistance exercise increased the expression of a 11-miRNA profile grouped into two functional clusters. Using both genetically modified animal models and in vitro approaches, we have identified miR-29a-3p as a novel myokine secreted into the bloodstream as EV cargo by contracting skeletal muscle. It is a cornerstone in the adaptation to resistance training by mediating the coordinated expression and secretion of other miRNAs and affecting muscle mass development and energy metabolism in muscle and liver. Taken together, our study suggests a coordinating and determinant role of miR-29a-3p in the response and adaptation to resistance training, possibly due to its role as a myokine through its regulatory role in energy metabolism.

During aging, modifiable lifestyle factors, such as physical activity, play an increasingly important role. Specifically, it is known that physical fitness declines relatively predictably with age and that resistance training can be a highly effective strategy for preventing this decline, both at muscular and cognitive levels. Several studies have described that one of the mechanisms mediating some of the beneficial effects of physical exercise during aging is the regulation of miRNAs, and in particular, the miR-29 family appears to play a relevant role. In this review, we analyse, firstly, the relevance of the miR-29 family in aging and, secondly, the protective effects of resistance exercise in delaying age-related dysfunction through the regulation of miR-29.