Sex differences in amino acids lost via sweating could lead to differential susceptibilities to disturbances in nitrogen balance and collagen turnover

Effects of radiation mitigating amino acid mixture on mice of different sexes

To date, few FDA-approved medical countermeasures are available for addressing hematopoietic acute radiation syndrome (H-ARS). In this study, we present our latest research findings focusing on the evaluation of a novel radiation mitigator known as the mitigating amino acid mixture (MAAM). MAAM is composed of five amino acids as the recently reported amino acid-based oral rehydration solution for mitigating gastrointestinal (GI)-ARS. CD2F1 male and female mice were exposed to 60Co-γ total body irradiation (TBI) at 9.0 or 9.5 Gy. Following irradiation, mice were orally administered with MAAM or a saline vehicle control once daily for a duration of 14 days, commencing 24 h after TBI. Mouse survival and body weight change were monitored for 30 days after irradiation. Complete blood counts (CBCs), bone marrow (BM) stem and progenitor cell survival (clonogenicity), and a serum cytokine antibody array were analyzed using samples from day 30 surviving mice. Our data revealed that MAAM treatment significantly enhanced survival rates in irradiated male CD2F1 mice, and the survival rate increased from 25% in the vehicle control group to 60% in the MAAM-treated group (p < 0.05) after 9.0 Gy TBI. The number of BM colonies significantly increased from 41.8 ± 6.4 /104 cells (in the vehicle group) to 78.5 ± 17.0 /104 cells (in the MAAM group) following 9.0 Gy TBI. Furthermore, MAAM treatment led to a decrease in the levels of six cytokines/proteins [cluster of differentiation 40 (CD40), interleukin (IL)-17A, C-X-C motif chemokine 10 (CXCL10/CRG-2), cutaneous T cell-attracting chemokine (CTACK), macrophage inflammatory protein (MIP)-3β, and IL-1β] and an increase in the levels of five other cytokines/proteins [IL-3Rβ, IL-5, leptin, IL-6, and stem cell factor (SCF)] in mouse serum compared to the vehicle group after 9.0 Gy TBI. However, similar alleviating effects of MAAM were not observed in the irradiated CD2F1 female mice. The serum cytokine profile in the irradiated female mice was different compared to the irradiated male mice. In summary, our data suggest that the beneficial effects of the mitigative amino acid combination treatment after radiation exposure may depend on sex.

Amino acid distribution in blood following high-intensity interval exercise: a preliminary study

This study investigated the effect of high-intensity interval exercise on total and individual amino acid concentrations in red blood cells (RBCs) and plasma. Seven males (31 ± 13 yr) provided venous blood samples at rest, immediately and 15 min and 30 min following an 8-min high-intensity exercise bout. The exercise bout was 16 × 15 s cycle efforts at 0.4N/kg of body mass and 90 rpm, interspersed with 15 s passive recovery. Total and individual amino acid concentrations of RBC and plasma and blood cell parameters were analysed. No significant differences for total amino acid concentrations between RBC and plasma were found. Individual amino acid analyses showed significant interaction effects for alanine and α-aminoadipic acid (P < 0.05), with plasma alanine significantly increased from baseline across the recovery period (P < 0.001). Blood fraction (group) effects showed greater concentrations of glycine, serine, asparagine, aspartic acid, glutamic acid, α-aminoadipic acid and ornithine in RBC, while greater concentrations of alanine, α-aminobutyric acid, valine, leucine, isoleucine, threonine, proline, phenylalanine, glutamine, tryptophan and cystine were found in plasma (P < 0.05). Comparable levels of histidine, lysine and tyrosine were observed between blood fractions. Significant differences in the variation of total amino acids in RBC were reported with higher variance at rest compared to following exercise (P = 0.01). Haemoglobin, pack cell volume and white blood cell count significantly increased immediately following exercise (P < 0.05) but returned to baseline after 15 min recovery. These results support the notion of individualised amino acid transportation roles for RBC and plasma during exercise.

Insight into mechanisms of creatinine optical sensing using fluorescein-gold complex

Creatinine level in biological fluids is a clinically relevant parameter to monitor vital functions and it is well assessed that measuring creatinine levels in the human body can be of great utility to evaluate renal, muscular, or thyroid dysfunctions. The accurate detection of creatinine levels may have a critical role in providing information on health status and represents a tool for the early diagnosis of severe pathologies. Among different methods for creatinine detection that have been introduced and that are evolving with increasing speed, fluorescence-based and colorimetric sensors represent one of the best alternatives, thanks to their affordability, sensitivity and easy readability. In this work, we demonstrate that the fluorescein-Au3+ complex provides a rapid, selective, and sensitive tool for the quantification of creatinine concentrations in ranges typical of sweat and urine. UV-visible absorption, diffuse reflectance spectroscopy, steady state and time resolved fluorescence spectroscopy were used to shed light on the molecular mechanisms involved in the changes of optical properties, which underlie the multiplexed sensor analytical reply. Interestingly, sensing can be performed in solution or on solid nylon support accessing different physiological concentrations from micromolar to millimolar range. As a proof-of-concept, the nylon-based platform was used to demonstrate its effectiveness in creatinine detection on a solid and flexible substrate, showing its analytical colorimetric properties as an easy and disposable creatinine point-of-care test.

Quantification and source characterization of volatile organic compounds from exercising and application of chlorine-based cleaning products in a university athletic center

Humans spend approximately 90% of their time indoors, impacting their own air quality through occupancy and activities. Human VOC emissions indoors from exercise are still relatively uncertain, and questions remain about emissions from chlorine-based cleaners. To investigate these and other issues, the ATHLETic center study of Indoor Chemistry (ATHLETIC) campaign was conducted in the weight room of the Dal Ward Athletic Center at the University of Colorado Boulder. Using a Vocus Proton-Transfer-Reaction Time-of-Flight Mass Spectrometer (Vocus PTR-TOF), an Aerodyne Gas Chromatograph (GC), an Iodide-Chemical Ionization Time-of-Flight Mass Spectrometer (I-CIMS), and Picarro cavity ringdown spectrometers, we alternated measurements between the weight room and supply air, allowing for determination of VOC, NH₃ , H₂ O, and CO₂ emission rates per person (emission factors). Human-derived emission factors were higher than previous studies of measuring indoor air quality in rooms with individuals at rest and correlated with increased CO₂ emission factors. Emission factors from personal care products (PCPs) were consistent with previous studies and typically decreased throughout the day. In addition, N-chloraldimines were observed in the gas phase after the exercise equipment was cleaned with a dichlor solution. The chloraldimines likely originated from reactions of free amino acids with HOCl on gym surfaces.

Sweat metabolome and proteome: Recent trends in analytical advances and potential biological functions

Metabolome and proteome profiling of biofluids, e.g., urine, plasma, has generated vast and ever-increasing amounts of knowledge over the last few decades. Paradoxically, omics analyses of sweat, one of the most readily available human biofluids, have lagged behind. This review capitalizes on the current knowledge and state of the art analytical advances of sweat metabolomics and proteomics. Moreover, current applications of sweat omics such as the discovery of disease biomarkers and monitoring athletic performance are also presented in this review. Another area of emerging knowledge that has been highlighted herein lies in the role of skin host-microbiome interactions in shaping the sweat metabolite-protein profiles. Discussion of future research directions describes the need to have a better grasp of sweat chemicals and to better understand how they function as aided by advances in omics tools. Overall, the role of sweat as an information-rich biofluid that could complement the exploration of the skin metabolome/proteome is emphasized.

Trace amines produced by skin bacteria accelerate wound healing in mice

Certain skin bacteria are able to convert aromatic amino acids (AAA) into trace amines (TA) that act as neuromodulators. Since the human skin and sweat contain a comparatively high content of AAA one can expect that such bacteria are able to produce TA on our skin. Here we show that TA-producing Staphylococcus epidermidis strains expressing SadA are predominant on human skin and that TA accelerate wound healing. In wounded skin, keratinocytes produce epinephrine (EPI) that leads to cell motility inhibition by β2-adrenergic receptor (β2-AR) activation thus delay wound healing. As β2-AR antagonists, TA and dopamine (DOP) abrogate the effect of EPI thus accelerating wound healing both in vitro and in a mouse model. In the mouse model, the S. epidermidis wild type strain accelerates wound healing compared to its ΔsadA mutant. Our study demonstrates that TA-producing S. epidermidis strains present on our skin might be beneficial for wound healing.

Dry sweat as sample for metabolomics analysis

Sweat is gaining popularity in clinical metabolomics as this biofluid is non-invasively sampled and its composition is modified by several pathologies. There is a lack of standardized strategies for collection of human sweat. Most studies have been carried out with fresh sweat collected after stimulation. A promising and simple alternative is sampling dry sweat by a solid support impregnated with a suited solvent. This research was aimed at comparing the metabolomics coverage provided by dry sweat collected by two solid supports (gauzes and filter papers) impregnated with different solvents. The dissolved dry sweat was analyzed by a dual approach: gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Among the tested sampling strategies, filter paper impregnated with 1:1 (v/v) ethanol‒phosphate buffer resulted the combination providing the highest metabolomics coverage (tentative identification of one hundred seventy-five compounds). Dry and fresh sweat were compared by using pools from the same individuals to evaluate compositional differences. Families of metabolites such as carnitines, sphingolipids and N-acyl-amino acids, among others, were exclusively identified in dry sweat. Comparison of both samples allowed concluding that dry sweat is better for analysis of low polar metabolites and fresh sweat is more suited for polar compounds. As most of the identified metabolites are involved in key biochemical pathways, this study opens interesting possibilities to the use of dry sweat as a source of metabolite markers for specific disorders. Sampling of dry sweat could provide a standardized approach for collection of this biofluid, thus overcoming the variability limitations of fresh sweat.

Modelling of protein turnover provides insight for metabolic demands on those specific amino acids utilised at disproportionately faster rates than other amino acids

The nitrogen balance is regulated by factors such as diet, physical activity, age, pathogenic challenges, and climatic conditions. A paradigm was developed from published recommended rates of protein intake (g/kg/day) with corresponding rates of endogenous protein turnover and excretion, to extrapolate amino acid balances under various conditions. The average proportions of amino acids in the ingested proteins representing a well-balanced diet were used to assess intake and an average human composition profile from five major high-turnover proteins in the body to assess endogenous protein turnover. The amino acid excretion profiles for urine and sweat were constructed for males and females from published data. The model calculated the nitrogen balances for a range of amino acids to determine the amino acid requirements to support daily exertion. Histidine, serine, glycine, and ornithine were in negative balances in males and females and this potential deficit was greater in the higher body-mass ranges. Conversely, leucine, isoleucine, and valine were conserved during nitrogen flux and resulted in positive balances. The model was run under a scenario of high demand for the synthesis of IgG during a response to an infectious challenge which indicated that these were increased requirements for tyrosine, threonine, and valine. It was concluded that these amino acids represent points of limitation to anabolic metabolism by restriction of their supply at critical times of demand. This would especially occur under conditions of fitness training, maintaining intensive exercise regimes, facilitating responses to pathogenic challenge, or recovery from injury.