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β-Alanine (BA) is one of the most widely used sport supplements, due to its capacity to improve high-intensity exercise performance by increasing muscle carnosine (MCarn) content, and consequently, the buffering capacity of the muscle. BA is also available in a variety of animal foods, but little is currently known about the influence of dietary BA intake on MCarn. The aim of the current study was to compile a detailed summary of available data on the BA content of commonly consumed foods, and to explore whether associations could be detected between self-reported dietary BA intake and skeletal MCarn in a group of 60 healthy, active, omnivorous men and women. Dietary BA intake was assessed via 3-day food records, and MCarn content assessed by high-performance liquid chromatography. A series of univariate and multivariate linear regression models were used to explore associations between estimated dietary BA and MCarn. No evidence of associations between dietary BA intake and MCarn were identified, with effect sizes close to zero calculated from models accounting for key demographic variables (f² ≤ 0.02 for all analyses). These findings suggest that capacity to increase MCarn via dietary strategies may be limited, and that supplementation may be required to induce increases of the magnitude required to improve performance. [ABSTRACT FROM AUTHOR]

This study investigated the impact of intensive endurance exercise on circulating androgenic steroid hormones in women. Fifteen normally menstruating athletic women participated. They completed intensive endurance exercise (treadmill running) until volitional fatigue in their follicular phase, with blood samples collected at pre-exercise, volitional fatigue, 90 min and 24 h into recovery. The steroid hormones (total, free testosterone, dehydroepiandrosterone [DHEA], and DHEA-sulfate [DHEA-S], cortisol) were analyzed in blood sera. Non-parametric statistics were used to assess changes across exercise and recovery. At volitional fatigue, all hormones, except free testosterone, were significantly (p < 0.05) increased compared to pre-exercise levels. Most hormones remained elevated through 90 min of recovery, with DHEA, DHEA-S, and total testosterone changes being significant (p < 0.05). At 24 h of recovery, hormonal levels were reduced; specifically, DHEA, DHEA-S, and total testosterone compared to baseline (p < 0.01 to 0.06). Increases in cortisol levels at volitional fatigue and 90 min of recovery were correlated with reductions in total testosterone, DHEA, and DHEA-S observed at 24 h of recovery (rho > −0.62, p < 0.05). In conclusion, in menstruating women performing intensive endurance exercise during their follicular phase, their androgenic steroid hormones remain elevated during early recovery but are suppressed at 24 h of recovery. The latter finding indicates that establishing a resting endocrine equilibrium requires a longer recovery period than 24 h. [ABSTRACT FROM AUTHOR]

Purpose: Women's professional cycling has grown in popularity, and this increase is also apparent in Brazil, which has increased its female cycling calendar in recent years. The aim of this observational study was to (1) determine training and competition loads of a top-level Brazilian female cycling team, (2) evaluate nutrition and clinical health, and (3) measure whether exercise capacity changed throughout the season. Methods: Training and competition data were collected over the season using global positioning system monitors, while laboratory-based physiological and performance measures (incremental cycling test, 30-s Wingate, 4-km time trial) and clinical and nutritional analyses were performed at time points throughout the season. Results: Total distance covered over the year was 11,124 (2895) km (7382–14,698 km). Endurance capacity was reduced over the season (P =.005) but not anaerobic power (all P >.05). Nutrition and stress markers remained largely unchanged throughout the season, although there were some individual fluctuations in some measures, and testosterone concentration was low for some. Median estimated energy availability ranged between 32.3 and 56.8 kcal·kgLBM−1·d−1 during training and 26.4 and 53.8 kcal·kgLBM−1·d−1 during competition. Percentage of training spent in optimal estimated energy availability was generally low, with 3 athletes spending <35% within the optimal intake. Conclusions: Substantial training and competition loads of the monitored professional Brazilian female cyclists may have reduced exercise capacity toward the end of the season, indicative of a grueling yearlong schedule. Several athletes may have had suboptimal energy availability during the season, potentially affecting testosterone concentration. These data demonstrate the difficulties in maintaining optimal nutrition, health, and performance throughout a season in professional female cycling and highlight the need for quality sport-science support for this type of top-level athlete. [ABSTRACT FROM AUTHOR]

Currently, little is known about the extent of interindividual variability in response to beta-alanine (BA) supplementation, nor what proportion of said variability can be attributed to external factors or to the intervention itself (intervention response). To investigate this, individual participant data on the effect of BA supplementation on a high-intensity cycling capacity test (CCT110%) were meta-analyzed. Changes in time to exhaustion (TTE) and muscle carnosine were the primary and secondary outcomes. Multilevel distributional Bayesian models were used to estimate the mean and SD of BA and placebo group change scores. The relative sizes of group SDs were used to infer whether observed variation in change scores were due to intervention or non-intervention-related effects. Six eligible studies were identified, and individual data were obtained from four of these. Analyses showed a group effect of BA supplementation on TTE (7.7, 95% credible interval [CrI] [1.3, 14.3] s) and muscle carnosine (18.1, 95% CrI [14.5, 21.9] mmol/kg DM). A large intervention response variation was identified for muscle carnosine (σIR = 5.8, 95% CrI [4.2, 7.4] mmol/kg DM) while equivalent change score SDs were shown for TTE in both the placebo (16.1, 95% CrI [13.0, 21.3] s) and BA (15.9, 95% CrI [13.0, 20.0] s) conditions, with the probability that SD was greater in placebo being 0.64. In conclusion, the similarity in observed change score SDs between groups for TTE indicates the source of variation is common to both groups, and therefore unrelated to the supplement itself, likely originating instead from external factors such as nutritional intake, sleep patterns, or training status. [ABSTRACT FROM AUTHOR]

The foreign body response impedes the function and longevity of implantable drug delivery devices. As a dense fibrotic capsule forms, integration of the device with the host tissue becomes compromised, ultimately resulting in device seclusion and treatment failure. We present FibroSensing Dynamic Soft Reservoir (FSDSR), an implantable drug delivery device capable of monitoring fibrotic capsule formation and overcoming its effects via soft robotic actuations. Occlusion of the FSDSR porous membrane was monitored over 7 days in a rodent model using electrochemical impedance spectroscopy. The electrical resistance of the fibrotic capsule correlated to its increase in thickness and volume. Our FibroSensing membrane showed great sensitivity in detecting changes at the abiotic/biotic interface, such as collagen deposition and myofibroblast proliferation. The potential of the FSDSR to overcome fibrotic capsule formation and maintain constant drug dosing over time was demonstrated in silico and in vitro. Controlled closed loop release of methylene blue into agarose gels (with a comparable fold change in permeability relating to 7 and 28 days in vivo) was achieved by adjusting the magnitude and frequency of pneumatic actuations after impedance measurements by the FibroSensing membrane. By sensing fibrotic capsule formation in vivo, the FSDSR will be capable of probing and adapting to the foreign body response through dynamic actuation changes. Informed by real-time sensor signals, this device offers the potential for long-term efficacy and sustained drug dosing, even in the setting of fibrotic capsule formation. [ABSTRACT FROM AUTHOR]

Analysing the composition and organisation of the fibrous capsule formed as a result of the Foreign Body Response (FBR) to medical devices, is imperative for medical device improvement and biocompatibility. Typically, analysis is performed using histological techniques which often involve random sampling strategies. This method is excellent for acquiring representative values but can miss the unique spatial distribution of features in 3D, especially when analysing devices used in large animal studies. To overcome this limitation, we demonstrate a non-destructive method for high-resolution large sample imaging of the fibrous capsule surrounding human-sized implanted devices using diffusion tensor imaging (DTI). In this study we analyse the fibrous capsule surrounding two unique macroencapsulation devices that have been implanted in a porcine model for 21 days. DTI is used for 3D visualisation of the microstructural organisation and validated using the standard means of fibrous capsule investigation; histological analysis and qualitative micro computed tomography (microCT) and scanning electron microscopy (SEM) imaging. DTI demonstrated the ability to distinguish microstructural differences in the fibrous capsules surrounding two macroencapsulation devices made from different materials and with different surface topographies. DTI-derived metrics yielded insight into the microstructural organisation of both capsules which was corroborated by microCT, SEM and histology. The non-invasive characterisation of the integration of implants in the body has the potential to positively influence analysis methods in pre-clinical studies and accelerate the clinical translation of novel implantable devices. [ABSTRACT FROM AUTHOR]