The blood serum metabolome profile after different phases of a 4-km cycling time trial: Secondary analysis of a randomized controlled trial.

It has been assumed that exercise intensity variation throughout a cycling time trial (TT) occurs in alignment of various metabolic changes to prevent premature task failure. However, this assumption is based on target metabolite responses, which limits our understanding of the complex interconnection of metabolic responses during exercise. The current study characterized the metabolomic profile, an untargeted metabolic analysis, after specific phases of a cycling 4-km TT. Eleven male cyclists performed three separated TTs in a crossover counterbalanced design, which were interrupted at the end of the fast-start (FS, 600 ± 205 m), even-pace (EP, 3600 ± 190 m), or end-spurt (ES, 4000 m) phases. Blood samples were taken before any exercise and 5 min after exercise cessation, and the metabolomic profile characterization was performed using Nuclear Magnetic Resonance metabolomics. Power output (PO) was also continually recorded. There were higher PO values during the FS and ES compared to the EP (all p < 0.05), which were accompanied by distinct metabolomic profiles. FS showed high metabolite expression in TCA cycle and its related pathways (e.g., glutamate, citric acid, and valine metabolism); whereas, the EP elicited changes associated with antioxidant effects and oxygen delivery adjustment. Finally, ES was related to pathways involved in NAD turnover and serotonin metabolism. These findings suggest that the specific phases of a cycling TT are accompanied by distinct metabolomic profiles, providing novel insights regarding the relevance of specific metabolic pathways on the process of exercise intensity regulation.

Modulation of the gut microbiota by probiotics and symbiotics is associated with changes in serum metabolite profile related to a decrease in inflammation and overall benefits to metabolic health: a double-blind randomized controlled clinical trial in women with obesity.

Modulation of the gut microbiota may help in treating obesity by improving host metabolic health. We aimed to evaluate the effects of probiotics or symbiotics on body weight and serum metabolite profile in women with obesity. A double-blind, parallel, randomized, controlled clinical trial was conducted with 32 adult women with body mass index ranging from 30 to 34.9 kg m-2. Volunteers followed a low-energy diet and were subjected to 8 weeks intervention: probiotic group (PG - Bifidobacterium lactis UBBLa-70, n = 10), symbiotic group (SG - Bifidobacterium lactis UBBLa-70 and fructooligosaccharide, n = 11), or control group (CG - placebo, n = 11). Analyses of anthropometric variables, gut microbiota and serum metabolites by 1H nuclear magnetic resonance (NMR) were performed at baseline and after the intervention. Multivariate statistics showed that all groups presented a decrease in glycerol and increase in arginine, glutamine and 2-oxoisovalerate. Therefore, a low-energy diet per se promoted changes in the metabolite profile related to decreased inflammation and positive effects on body weight. SG presented unique changes in metabolites (increase in pyruvate and alanine and decrease in citrate and BCAA). Negative correlations between arginine and glutamine with fat mass were observed in the SG. PG presented a decrease in 1H NMR lipid signals and negative correlation between Verrucomicrobia and Firmicutes with (CH2)n lipids. Both probiotics and symbiotics promoted changes in metabolites related to improved metabolic health. Specific metabolite changes following symbiotic intervention might suggest some advantage in providing Bifidobacterium lactis in combination with fructooligosaccharide in a low-energy diet, rather than probiotics or diet alone. Clinical trial: NCT02505854.

Nefrolitiasis: fisiopatología, evaluación metabólica y manejo terapéutico / Nephrolithiasis: pathofisiology, metabolic evaluation, and therapy

La nefrolitiasis es un trastorno frecuente en países desarrollados y en desarrollo. Su prevalencia varía entre el 4 y 20% según diferentes series y depende de la edad de la población analizada, las condiciones geográficas y socioeconómicas del grupo en estudio. La prevalencia de litiasis renal aumenta con la edad tanto en varones como en mujeres; es más común en varones jóvenes. Una de las características de la litiasis renal es la alta recurrencia y muchas veces la solución de los cólicos requiere de intervenciones endoscópicas u otro tratamiento urológico y esto hace a la morbilidad de la enfermedad. El promedio de diferentes trabajos que estudiaron la evolución natural de la enfermedad muestra que la posibilidad de recurrencia al año del primer episodio es del 15%, a los 5 años 40% y a los 10 años del 60%. Tanto los factores genéticos como los medioambientales contribuyen a la formación de cálculos. Los factores genéticos explican la tendencia a la agregación familiar de la enfermedad. El rol de la herencia es claro en algunas enfermedades como cistinuria o hiperoxalurias primarias, pero la litiasis idiopática también tiene una tendencia familiar, si bien los genes involucrados aún no se conocen. Dentro de los factores medioambientales se destaca la dieta, o sea determinados hábitos de ingesta que expresan la propensión a la litogénesis que tienen algunos sujetos. En aproximadamente 90% de los afectados es posible identificar alteraciones metabólicas que ayudan no sólo al diagnóstico etiológico sino que permiten también un manejo adecuado, con modificaciones dietéticas e intervenciones farmacológicas específicas. El tratamiento es eficaz en disminuir significativamente la tasa de recurrencias. En esta revisión analizamos la fisiopatología de la hipercalciuria, la hiperoxaluria, la hipocitraturia, y las litiasis úrica y cistínica. Se detallan el manejo del cólico renal y el tratamiento dietético y farmacológico apropiado para cada tipo de litiasis.