Sweat Proteins Research Articles

A wireless patch for the monitoring of C-reactive protein in sweat.

The quantification of protein biomarkers in blood at picomolar-level sensitivity requires labour-intensive incubation and washing steps. Sensing proteins in sweat, which would allow for point-of-care monitoring, is hindered by the typically large interpersonal and intrapersonal variations in its composition. Here we report the design and performance of a wearable and wireless patch for the real-time electrochemical detection of the inflammatory biomarker C-reactive (CRP) protein in sweat. The device integrates iontophoretic sweat extraction, microfluidic channels for sweat sampling and for reagent routing and replacement, and a graphene-based sensor array for quantifying CRP (via an electrode functionalized with anti-CRP capture antibodies-conjugated gold nanoparticles), ionic strength, pH and temperature for the real-time calibration of the CRP sensor. In patients with chronic obstructive pulmonary disease, with active or past infections or who had heart failure, the elevated concentrations of CRP measured via the patch correlated well with the protein's levels in serum. Wearable biosensors for the real-time sensitive analysis of inflammatory proteins in sweat may facilitate the management of chronic diseases.

Sweat Proteomics in Cystic Fibrosis: Discovering Companion Biomarkers for Precision Medicine and Therapeutic Development.

In clinical routine, the diagnosis of cystic fibrosis (CF) is still challenging regardless of international consensus on diagnosis guidelines and tests. For decades, the classical Gibson and Cooke test measuring sweat chloride concentration has been a keystone, yet, it may provide normal or equivocal results. As of now, despite the combination of sweat testing, CFTR genotyping, and CFTR functional testing, a small fraction (1–2%) of inconclusive diagnoses are reported and justifies the search for new CF biomarkers. More importantly, in the context of precision medicine, with a view to early diagnosis, better prognosis, appropriate clinical follow-up, and new therapeutic development, discovering companion biomarkers of CF severity and phenotypic rescue are of utmost interest. To date, previous sweat proteomic studies have already documented disease-specific variations of sweat proteins (e.g., in schizophrenia and tuberculosis). In the current study, sweat samples from 28 healthy control subjects and 14 patients with CF were analyzed by nanoUHPLC-Q-Orbitrap-based shotgun proteomics, to look for CF-associated changes in sweat protein composition and abundance. A total of 1057 proteins were identified and quantified at an individual level, by a shotgun label-free approach. Notwithstanding similar proteome composition, enrichment, and functional annotations, control and CF samples featured distinct quantitative proteome profiles significantly correlated with CF, accounting for the respective inter-individual variabilities of control and CF sweat. All in all: (i) 402 sweat proteins were differentially abundant between controls and patients with CF, (ii) 68 proteins varied in abundance between F508del homozygous patients and patients with another genotype, (iii) 71 proteins were differentially abundant according to the pancreatic function, and iv) 54 proteins changed in abundance depending on the lung function. The functional annotation of pathophysiological biomarkers highlighted eccrine gland cell perturbations in: (i) protein biosynthesis and trafficking, (ii) CFTR proteostasis and membrane stability, and (iii) cell-cell adherence, membrane integrity, and cytoskeleton crosstalk. Cytoskeleton-related biomarkers were of utmost interest because of the consistency between variations observed here in CF sweat and variations previously documented in other CF tissues. From a clinical stance, nine candidate biomarkers of CF diagnosis (CUTA, ARG1, EZR, AGA, FLNA, MAN1A1, MIA3, LFNG, SIAE) and seven candidate biomarkers of CF severity (ARG1, GPT, MDH2, EML4 (F508del homozygous), MGAT1 (pancreatic insufficiency), IGJ, TOLLIP (lung function impairment)) were deemed suitable for further verification.

Differential involvement of glycans in the binding of Staphylococcus epidermidis and Corynebacterium spp. to human sweat

Sweat is a secretory fluid that can be a source of unpleasant body odour due to interaction of resident bacteria with sweat components. Identification of glycoproteins in sweat suggests that protein-conjugated glycans may act as binding epitopes for bacteria, as found in other secretory fluids such as human milk, tears and saliva which help to protect epithelial surfaces from infection.We conducted proteomic and glycomic analysis of sweat to reveal an abundance of glycoproteins, predominantly carrying bi-antennary sialylated N-glycans with or without fucose. A fluorescent plate assay was used to determine whether glycans on sweat proteins provide binding epitopes for odour-producing skin commensals Staphylococcus epidermidis and Corynebacterium. Sialic acid and fucose were found to be important binding epitopes for S. epidermidis 3-22-BD-6, a strain recently isolated from human sweat, whereas fucose (but not sialic acid) contributed to the binding of Type strain S. epidermidis ATCC 12228. In contrast, our results indicate that sweat N-glycans do not provide binding epitopes for Corynebacterium.Synthetic sugar mimics of Lewis blood group antigens were investigated as potential inhibitors of the binding of S. epidermidis 3-22-BD-6 to sweat. Pre-incubation of the bacterium with LeB, LeX, LeY and sLeX (pentaose) resulted in a significant reduction in sweat protein adhesion indicating that terminal fucose is a key binding epitope, particularly when linked to a Type 2 chain (Galβ1-4GlcNAc) configuration (LeY).Our results form an impetus for future studies seeking to elucidate the role of glycans in sweat associated malodour, with possible implications for cosmetic and medical fields.

Proteomic and peptidomic analysis of human sweat with emphasis on proteolysis

Sweat is produced by eccrine and apocrine glands and represents a biological fluid with established roles in thermo-regulation and host infection defense. The composition of sweat is highly dynamic and alters significantly in various skin and other disorders. Therefore, in-depth profiling of sweat protein composition is expected to augment our understanding of the pathobiology of several skin diseases and may lead to the identification of useful sweat-based disease biomarkers. We here reported an in-depth analysis of the human sweat proteome and peptidome. Sweat was collected from healthy males and healthy females of ages 20–60years, following strenuous exercise. Two sweat pools were prepared (1 for males and 1 for females) and were subjected to sample preparation for mass spectrometric analysis. We identified a total of 861 unique proteins during our proteomic analysis and 32,818 endogenous peptides (corresponding to additional 1067 proteins) from our peptidomics workflow. As expected, the human skin was identified as the most abundant source of sweat proteins and peptides. Several skin proteases and protease inhibitors were identified in human sweat, highlighting the intense proteolytic activity of human skin. The presence of several antimicrobial peptides supports the functional roles of sweat in host defense and innate immunity. SignificanceSweat is a skin-associated biological fluid, secreted by eccrine and apocrine glands, with essential function in body thermo-regulation and host infection defense. In the present study, we performed in-depth profiling of both sweat proteome and peptidome composition. Our data provide the most in-depth characterization of the skin's catalytic network present in sweat. For the first time, we brought to light novel peptides in human sweat that potentially have antimicrobial activity, which highlight the important role of this fluid in innate immunity. All these findings allow us to have a better understanding of the complex web of proteases in skin and may act as a platform for the future discovery of novel skin biomarkers.

The mechanism of eccrine sweat pore plugging by aluminium salts using microfluidics combined with small angle X-ray scattering

Aluminium salts are widely used to control sweating for personal hygiene purposes. Their mechanism of action as antiperspirants was previously thought to be a superficial plugging of eccrine sweat pores by the aluminium hydroxide gel. Here we present a microfluidic T junction device that mimics sweat ducts, and is designed for the real time study of interactions between sweat and ACH (Aluminium Chloro Hydrate) under conditions that lead to plug formation. We used this device to image and measure the diffusion of aluminium polycationic species in sweat counter flow. We report the results of small angle X-ray scattering experiments performed to determine the structure and composition of the plug, using BSA (Bovine Serum Albumin) as a model of sweat proteins. Our results show that pore occlusion occurs as a result of the aggregation of sweat proteins by aluminium polycations. Mapping of the device shows that this aggregation is initiated in the T junction at the location where the flow of aluminium polycations joins the flow of BSA. The mechanism involves two stages: (1) a nucleation stage in which aggregates of protein and polycations bind to the wall of the sweat duct and form a tenuous membrane, which extends across the junction; (2) a growth stage in which this membrane collects proteins that are carried by hydrodynamic flow in the sweat channel and polycations that diffuse into this channel. These results could open up perspectives to find new antiperspirant agents with an improved efficacy.

Sweat Allergy.

For many years, sweat has been recognized as an exacerbation factor in all age groups of atopic dermatitis (AD) and a trigger of cholinergic urticaria (CholU). Recently, we reported the improvement of AD symptoms by spray with tannic acid, which suppresses basophil histamine release by semipurified sweat antigens in vitro, and showering that removes antigens in sweat from the skin surface. We finally identified MGL_1304 secreted by Malassezia globosa as a major histamine-releasing antigen in human sweat. MGL_1304 is detected as a 17-kDa protein in sweat and exhibits almost the highest histamine-release ability from basophils of patients with AD and CholU among antigens derived from Malassezia species. Moreover, serum levels of anti-MGL_1304 IgE of patients with AD and CholU were significantly higher than those of normal controls. Desensitization therapy using autologous sweat or MGL_1304 purified from culture of M. globosa or its cognates might be beneficial for patients with intractable CholU due to sweat allergy.

Highly abundant defense proteins in human sweat asrevealed by targeted proteomics and label-free quantification mass spectrometry.

The healthy human skin with its effective antimicrobial defense system forms an efficient barrier against invading pathogens. There is evidence suggesting that the composition of this chemical barrier varies between diseases, making the easily collected sweat an ideal candidate for biomarker discoveries. Our aim was to provide information about the normal composition of the sweat, and to study the chemical barrier found at the surface of skin. Sweat samples from healthy individuals were collected during sauna bathing, and the global protein panel was analysed by label-free mass spectrometry. SRM-based targeted proteomic methods were designed and stable isotope labelled reference peptides were used for method validation. Ninety-five sweat proteins were identified, 20 of them were novel proteins. It was shown that dermcidin is the most abundant sweat protein, and along with apolipoprotein D, clusterin, prolactin-inducible protein and serum albumin, they make up 91% of secreted sweat proteins. The roles of these highly abundant proteins were reviewed; all of which have protective functions, highlighting the importance of sweat glands in composing the first line of innate immune defense system, and maintaining the epidermal barrier integrity. Our findings with regard to the proteins forming the chemical barrier of the skin as determined by label-free quantification and targeted proteomics methods are in accordance with previous studies, and can be further used as a starting point for non-invasive sweat biomarker research.

Proteomic Analysis of Eccrine Sweat: Implications for the Discovery of Schizophrenia Biomarker Proteins

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) and multiple reaction monitoring mass spectrometry (MRM-MS) proteomics analyses were performed on eccrine sweat of healthy controls, and the results were compared with those from individuals diagnosed with schizophrenia (SZ). This is the first large scale study of the sweat proteome. First, we performed LC-MS/MS on pooled SZ samples and pooled control samples for global proteomics analysis. Results revealed a high abundance of diverse proteins and peptides in eccrine sweat. Most of the proteins identified from sweat samples were found to be different than the most abundant proteins from serum, which indicates that eccrine sweat is not simply a plasma transudate and may thereby be a source of unique disease-associated biomolecules. A second independent set of patient and control sweat samples were analyzed by LC-MS/MS and spectral counting to determine qualitative protein differential abundances between the control and disease groups. Differential abundances of selected proteins, initially determined by spectral counting, were verified by MRM-MS analyses. Seventeen proteins showed a differential abundance of approximately 2-fold or greater between the SZ pooled sample and the control pooled sample. This study demonstrates the utility of LC-MS/MS and MRM-MS as a viable strategy for the discovery and verification of potential sweat protein disease biomarkers.

The Human Sweat Proteome and Auto-IgE Responses to it's Components

RATIONALE: Previous studies have shown that human sweat contains proteins. The exact composition of these proteins however remains unclear. We have also observed that a proportion of atopic individuals complaining of itching more when they sweat and hypothesize that they may be reacting to their own sweat proteins.

Increase in dermcidin-derived peptides in sweat of patients with atopic eczema caused by a humorous video

Objective Dermcidin (DCD)-derived peptide is an antimicrobial peptide produced by the sweat glands. However, the levels of DCD-derived peptide in sweat were decreased in patients with atopic eczema (AE). The effect of viewing a humorous video on the levels of DCD-derived peptide was studied. Methods Twenty patients with AE viewed an 87-min humorous video (Modern Times, featuring Charlie Chaplin). Just before and immediately after viewing, sweat was collected, and the levels of DCD-derived peptide and total protein in sweat were measured. Results Viewing a humorous video increased the levels of DCD-derived peptide without affecting the levels of total protein in sweat. Conclusion Viewing a humorous video increased DCD-derived peptide in sweat of patients with AE, and thus, it may be helpful in the treatment of skin infection of AE.

Sweat protein vaitiations in exercise and raised temperature conditons in hot humid climate

Sweat protein vaitiations in exercise and raised temperature conditons in hot humid climate

Sweat composition: comparison of collection methods and effects of exercise intensity

SummaryThe objectives of this study were to compare sweat collection techniques and determine effect of low and high intensity exercise on the composition and osmolality of equine sweat in exercise trained Thoroughbred horses. Sweat collection sites included the neck and thorax, bilaterally and behind the girth ventrally. Sweat was collected in cotton gauze, either exposed to the air or contained within a plastic pouch, from sealed pouches, with or without application of vaseline to the skin, and as it dripped off the skin behind the girth (free catch). There were differences in the ionic composition of sweat collected by different techniques during and after low (50% V̇O2max) and after high (90% V̇O2max) intensity exercise. These changes were most consistent where collection technique minimised evaporative losses. With regard to collection method, ionic concentrations and osmolality were lowest in samples obtained from sealed pouches without vaseline on the skin. In samples obtained from cotton gauze and by free catch, osmolality, [Na] and [Cl] were significantly increased when compared with sweat collected from sealed pouches. In samples collected from sealed pouches during low intensity exercise, osmolality increased 11%, [Na] and [Cl] increased 26% and 9%, respectively and [K] decreased 14%. Osmolality and the concentrations of these ions did not change during recovery. In contrast, osmolality increased by 12% in the first 5 min following high intensity exercise. After both intensities of exercise, there was a significant decrease in the concentration of protein in sweat collected by all methods. Results indicate that collection technique had a marked effect on composition of sweat as demonstrated by increased osmolality and increased concentrations of Na and Cl in sweat collected in cotton gauze and by free catch.

Human Eccrine Sweat Contains Tissue Kallikrein and Kininase II

We attempted to determine the level of sweat kallikrein (kininogenase) and to purify and characterize it using sweat collected over a white petrolatum barrier. Thermally induced eccrine sweat obtained from 24 healthy subjects showed kallikrein activity of 24.4 ng kinins generated/1 mg of sweat protein when heated plasma was used as the substrate and 16.1 ng kinin when purified low molecular weight bovine kininogen was used as the substrate. Sweat was sequentially purified by Sephacryl S-200, diethyaminoethyl Sephacel, and fast flow liquid chromatography Mono Q chromatography. Sweat kallikrein had a M(r) of 40,000 and was inhibited by aprotinin but not by soybean trypsin inhibitor. The peptide generated by sweat kallikrein was identified as lys-bradykinin using reverse phase high-performance liquid chromatography and by its amino acid sequence. Anti-human urinary kallikrein immunoglobulin G neutralized the sweat kallikrein activity completely, indicating that the sweat kallikrein is the glandular type. Purified sweat and salivary kallikrein showed similar M(r) and responses to inhibitors and antibodies. Using immunohistochemistry, kallikrein activity was localized in luminal ductal cells and in the peripheral rim of secretory coil segments, presumably the outer membrane of the myoepithelium. We also observed kininase activity in sweat at M(r) 160,000, which was inhibited by ethylenediamine tetraacetic acid, captopril, and angiotensin converting enzyme inhibitor peptide, indicating that it is kininase II (or angiotensin converting enzyme). Sweat also contains abundant non-kallikrein hydrolases for S-2266 and S-2302. The demonstration of glandular kallikrein, its tissue localization, and the presence of kininase II in sweat provide the basis for future studies on the physiologic role of the kallikrein/kinin system in the eccrine sweat gland.

Age dependent reference intervals of glucose, urea, protein, lactate and electrolytes in thermally induced sweat.

Concentrations of electrolytes, lactate, urea, glucose, total lipids and total protein were measured in sweat obtained by thermal stimulation of apparently healthy volunteers. Blood and urine samples were also collected. Electrolytes, urea and total protein were also measured in serum. The concentrations of electrolytes, glucose and urea in sweat increased with age, and this increase was more apparent in males, probably due to certain age-related changes in male sweat glands. The concentrations of lactate, total protein and total lipids in sweat, however, were not age-dependent. The concentration of total protein was higher in females than in males. The concentrations of all the other analytes were higher in males than in females of the same age group.

The Protease as a Cleansing Agent and Its Stabilization by Chemical Modification.

The effect of protease as a cleansing agent and the improvement of protease stability by chemical modification with polyethylene glycol derivatives were studied. The proteolytic actions of Bioprase and papain on keratins and sweat proteins, which are major proteinic impurities on the skin, were compared. Bioprase degraded both more effectively than papain. Although Bioprase possesses potential usefulness as a cosmetic material, it has a defect: low staility in a system containing water. This defect prevents the application of Bioprase to various preparations except for powder-type preparations. To improve the stability of the native Bioprase, it was chemically modified with copolymers of α-allyl-ω-methoxy polyoxyethylene and maleic anhydride. The stability of Bioprase was extremely improved by the modification. The modified Bioprase was further stabilized by adding such polyols as 1, 3-butylene glycol, glycerin, and propylene glycol. Some nonionic surfactants did not decrease the stability of the modified Bioprase. This method for stabilization allows the application of enzyme to various preparations. By continual use of a cleansing preparation containing the modified Bioprase, skin conditions improved.

Sweat protein components tested by SDS-polyacrylamide gel electrophoresis followed by immunoblotting.

Sweat samples were collected in a sauna from 74 healthy volunteers (72 men and 2 women) and concentrated. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) of the individual samples revealed, in general, five main proteins and four PAS positive components. In pooled sweat, a method of SDS-PAGE followed by immunoblotting with specific antisera or antibodies against 24 human serum components was applied, and three out of the five main proteins showed the same molecular weights and antigenicities corresponding to serum albumin (67,000 Da), Zn-alpha 2-glycoprotein (42,000 Da) and lysozyme (14,000 Da). Moreover, orosomucoid, transferrin, IgG and IgA were demonstrated in the pooled sweat. Although alpha 1-antitrypsin was probably in the pooled sweat, other serum components could not be detected. On the pooled and individual sweat samples, anti-carcinoembryonic antigen (CEA) formed three bands at 42,000, 19,000 and 18,000 Da, but the antibody did not react with normal serum. It might be considered from these molecular weights that those sweat components are CEA-related antigens.

Proteolytic enzymes in human eccrine sweat: a screening study.

Thermally induced human eccrine sweat was collected both by simple scraping (SS) and by a polyethylene sweat collector that covered the Vaseline-coated skin of the back to minimize epidermal contamination (CS, clean sweat). Using synthetic chromogenic Kabi S-series substrates, we demonstrated a variety of proteases in both SS and CS, the former being higher than the latter to varying extents. The higher enzyme activity in SS is mainly due to epidermal contamination because abundant protease activity was eluted from the nonperspiring stripped and unstripped skin in vivo and from the stripped stratum corneum itself. The electrophoretic separation of sweat protein has shown that CS contains at least 7 and SS 15 gelatinolytic proteinases. Although some CS proteinases could be derived from the sweat duct, the sweat secretory coil itself is responsible for at least two proteinases at 78 and 25 kilodaltons. The identity and function of these enzymes remain to be studied.

The analysis of human sweat proteins by isoelectric focusing. I. Sweat collection utilizing the macroduct system demonstrates the presence of previously unrecognized sex-related proteins.

The presence of high concentrations of sodium in the sweat of patients with cystic fibrosis is widely accepted by all investigators as one of the most important manifestations of the genetic defect. However, the simple means of sweat collection utilized for diagnostic purposes has been extended to the biochemical and physical analysis of the macromolecular components of human sweat. The most popular technique for the attainment of sweat has been collection of sweat droplets from the skin surface following heat stimulation. In this report, it is demonstrated that a far superior means of sweat collection exists based on a new collection device called the MACRODUCT. Utilizing this device, in conjunction with thin-layer isoelectric focusing, demonstrated that human sweat contains sex-specific proteins expressed in adult males and absent or greatly decreased from females and prepubertal males. Additionally, results are presented which suggest that the presence of epidermal keratins are an excellent marker for sweat contaminated with nonsweat gland-derived macromolecules.

Analysis of human sweat proteins by two-dimensional electrophoresis and ultrasensitive silver staining

The polypeptide components of human sweat have been detected with the methylamine-incorporating silver stain (T. Marshall, 1984, Anal. Biochem., 136, 340–346) following high resolution two-dimensional electrophoresis. This technique reveals over 400 polypeptide components in 65 μl of unconcentrated human sweat.

Protein profile of goat sweat

The main source of skin surface protein is sweat glands. Studies on skin surface proteins of domestic animals have been made by Joshi etal. (1968), Jenkinson, Lloyd & Mabon (1976, 1979), Lloyd, Mabon & Jenkinson (1977) and Rai, More & Singh (1982). However, information on sweat proteins (skin surface proteins) of goats is lacking. The present study is an effort to characterize sweat proteins of goats and to compare them with those of sheep.