Metabo-tip: a metabolomics platform for lifestyle monitoring supporting the development of novel strategies in predictive, preventive and personalised medicine

Background/aims Exposure to bioactive compounds from nutrition, pharmaceuticals, environmental contaminants or other lifestyle habits may affect the human organism. To gain insight into the effects of these influences, as well as the fundamental biochemical mechanisms behind them, individual molecular profiling seems to be a promising tool and may support the further development of predictive, preventive and personalised medicine. Methods We developed an assay, called metabo-tip for the analysis of sweat, collected from fingertips, using mass spectrometry—by far the most comprehensive and sensitive method for such analyses. To evaluate this assay, we exposed volunteers to various xenobiotics using standardised protocols and investigated their metabolic response. Results As early as 15 min after the consumption of a cup of coffee, 50 g of dark chocolate or a serving of citrus fruits, significant changes in the sweat composition of the fingertips were observed, providing relevant information in regard to the ingested substances. This included not only health-promoting bioactive compounds but also potential hazardous substances. Furthermore, the identification of metabolites from orally ingested medications such as metamizole indicated the applicability of this assay to observe specific enzymatic processes in a personalised fashion. Remarkably, we found that the sweat composition fluctuated in a diurnal rhythm, supporting the hypothesis that the composition of sweat can be influenced by endogenous metabolic activities. This was further corroborated by the finding that histamine was significantly increased in the metabo-tip assay in individuals with allergic reactions. Conclusion Metabo-tip analysis may have a large number of practical applications due to its analytical power, non-invasive character and the potential of frequent sampling, especially regarding the individualised monitoring of specific lifestyle and influencing factors. The extraordinarily rich individualised metabolomics data provided by metabo-tip offer direct access to individual metabolic activities and will thus support predictive preventive personalised medicine.

Metabo-tip: a Metabolomics Platform for Lifestyle Monitoring

Exposure to bioactive compounds from nutrition, pharmaceuticals, environmental contaminants or other lifestyle habits may affect the human organism. To gain insight into the effects of these influences, as well as the fundamental biochemical mechanisms behind them, molecular profiling seems promising. To address this problem, we developed an assay for the analysis of sweat, collected from finger tips, using mass spectrometry – by far the most comprehensive and sensitive method for such analyses. To evaluate this assay, called metabo-tip, we exposed volunteers to various xenobiotics using standardized protocols and investigated their metabolic response. As early as 15 minutes after the consumption of a cup of coffee, 50g of dark chocolate or a serving of citrus fruits, significant changes in the sweat composition of the finger tips could be observed, providing relevant information in regards to the ingested substances. This included bioactive compounds such as natural flavonoids as well as potential hazardous substances such as pesticides. Furthermore, the identification of metabolites from nicotine after cigarette smoking and metabolites from orally ingested medications such as metamizole indicated the applicability of this assay to observe specific enzymatic processes. Remarkably, we found that the sweat composition fluctuated in a diurnal rhythm, supporting the hypothesis that the composition of sweat can be influenced by endogenous metabolic activities. This was further corroborated by the finding that histamine was significantly increased in the metabo-tip assay in individuals with allergic reactions. Metab-tip may thus enable direct access to individual metabolic profiles and may thus support predictive preventive personalised medicine (PPPM).

The (in)dependency of blood and sweat sodium, chloride, potassium, ammonia, lactate and glucose concentrations during submaximal exercise

Purpose To reduce the need for invasive and expensive measures of human biomarkers, sweat is becoming increasingly popular in use as an alternative to blood. Therefore, the (in)dependency of blood and sweat composition has to be explored. Methods In an environmental chamber (33 °C, 65% relative humidity; RH), 12 participants completed three subsequent 20-min cycling stages to elicit three different local sweat rates (LSR) while aiming to limit changes in blood composition: at 60% of their maximum heart rate (HRmax), 70% HRmax and 80% HRmax, with 5 min of seated-rest in between. Sweat was collected from the arm and back during each stage and post-exercise. Blood was drawn from a superficial antecubital vein in the middle of each stage. Concentrations of sodium, chloride, potassium, ammonia, lactate and glucose were determined in blood plasma and sweat. Results With increasing exercise intensity, LSR, sweat sodium, chloride and glucose concentrations increased (P ≤ 0.026), while simultaneously limited changes in blood composition were elicited for these components (P ≥ 0.093). Sweat potassium, lactate and ammonia concentrations decreased (P ≤ 0.006), while blood potassium decreased (P = 0.003), and blood ammonia and lactate concentrations increased with higher exercise intensities (P = 0.005; P = 0.007, respectively). The vast majority of correlations between blood and sweat parameters were non-significant (P > 0.05), with few exceptions. Conclusion The data suggest that sweat composition is at least partly independent of blood composition. This has important consequences when targeting sweat as non-invasive alternative for blood measurements.

Microfluidic Nonwoven-Based Device as a Potential Biosensor for Sweat Analysis

Monitoring body fluids such as sweat composition can provide useful information about the physiological status. Physiological monitoring of body fluids such as sweat with a textile-based system has the advantage of being non-invasive and easily accessible and such monitoring is beneficial to indicate information about body's physiological status. In the present study, it is aimed to design a textile-based system with non-invasive methods which can be used to monitor a sportsman's performance. A novel, disposable and wearable biochemical analytical device was designed and fabricated by patterning micro channels and reservoirs using SU-8 photoresist through photolithography technique on an absorbant bicomponent Evolon® nonwoven substrate. It was obtained that hydrophilic reservoirs were well defined and demarcated by hydrophobic barriers. Therefore, no liquid leakage was observed around the reservoirs which was crucial for achieving a proper enzyme immobilization and the successful detection of the color change after the simulated sweat was deposited on the hydrophilic reservoir areas. Analyte optimization studies revealed that color change became more evident with the increasing analyte concentration until 20 mM and started to decrease with further increase due to analyte inhibition. Also, on textile fabrics, color densities started to decrease after 40 mM analyte concentration.