Effects of sprint interval or combined aerobic and resistance training on myokines in overweight women with type 2 diabetes: A randomized controlled trial

Metabolic Health-The Role of Adipo-Myokines

Obesity is now a worldwide epidemic. In recent years, different phenotypes of obesity, ranging from metabolically healthy normal weight to metabolically unhealthy obese, were described. Although there is no standardized definition for these phenotypes or for metabolic health, the influence of lifestyle and early-life factors is undisputed. In this context, the ratio of muscle-to-fat tissue seems to play a crucial role. Both adipose tissue and skeletal muscle are highly heterogeneous endocrine organs secreting several hormones, with myokines and adipokines being involved in local autocrine/paracrine interactions and crosstalk with other tissues. Some of these endocrine factors are secreted by both tissues and are, therefore, termed adipo-myokines. High (cardiorespiratory) fitness as a surrogate parameter for an active lifestyle is epidemiologically linked to “better” metabolic health, even in the obese; this may be partly due to the role of adipo-myokines and the crosstalk between adipose and muscle tissue. Therefore, it is essential to consider (cardiovascular) fitness in the definition of metabolically healthy obese/metabolic health and to perform longitudinal studies in this regard. A better understanding of both the (early-life) lifestyle factors and the underlying mechanisms that mediate different phenotypes is necessary for the tailored prevention and personalized treatment of obesity.

Fibroblast Growth Factor 21 and the Adaptive Response to Nutritional Challenges

The Fibroblast Growth Factor 21 (FGF21) is considered an attractive therapeutic target for obesity and obesity-related disorders due to its beneficial effects in lipid and carbohydrate metabolism. FGF21 response is essential under stressful conditions and its metabolic effects depend on the inducer factor or stress condition. FGF21 seems to be the key signal which communicates and coordinates the metabolic response to reverse different nutritional stresses and restores the metabolic homeostasis. This review is focused on describing individually the FGF21-dependent metabolic response activated by some of the most common nutritional challenges, the signal pathways triggering this response, and the impact of this response on global homeostasis. We consider that this is essential knowledge to identify the potential role of FGF21 in the onset and progression of some of the most prevalent metabolic pathologies and to understand the potential of FGF21 as a target for these diseases. After this review, we conclude that more research is needed to understand the mechanisms underlying the role of FGF21 in macronutrient preference and food intake behavior, but also in β-klotho regulation and the activity of the fibroblast activation protein (FAP) to uncover its therapeutic potential as a way to increase the FGF21 signaling.

Novel Associations Between Interleukin-15 Polymorphisms and Post-training Changes of Body Composition Parameters in Young Nonobese Women

Based on the important role of interleukin-15 (IL-15) in human metabolism and, in consequence, in body composition modulation, we examined whether rs1589241 and rs1057972 polymorphisms, analyzed individually or in combination, would influence the effects of a training program. Accordingly, we studied the allele and genotype distribution in a group of 163 young nonobese Caucasian women measured for selected body mass and composition, as well as biochemical parameters before and after the completion of a 12-week endurance training program. After a week-long familiarization stage, low-high impact aerobics were conducted three times a week for 60 min, at an increasing intensity from about 50 to 80% of HRmax. With reference to rs1057972 genotypes, there were two significant genotype × training interactions, in which (i) fat mass percentage (FM%) significantly decreased among the AA homozygotes (p = 0.00002) and AT heterozygotes (p = 0.00002), and (ii) fat free mass (FFM) increased only among the AT heterozygotes (p = 0.0003), whereas in the AA homozygotes there was only a borderline significance (p = 0.065). No genotype × training interactions were found for the second rs1589241 polymorphism. Moreover, the carriers of the[T;A] haplotype (when compared with reference haplotype) displayed significant decrease in FM% (p = 0.027) and increase in FFM (p = 0.014) in response to the applied training program. Our data highlight novel associations between specific IL-15 genotype and different post-training changes of FM% and FFM parameters. The results suggest that harboring the rs1057972 A allele and/or the [T;A] haplotype is favorable for achieving specific positive training-induced body composition changes.