Steroid analysis of human apocrine secretion

Sebaceous origins of human odor

The compounds that make up human body odor have been catalogued by researchers in many fields. Yet few are aware of exactly where these molecules come from. Volatile body-odor compounds are often cited as being produced primarily via microbial activity from precursors in sweat. While this is a source of many human volatiles, here we synthesize data showing that some of the most distinctive and abundant components of human odor instead originate from precursors in sebum, via reactions that do not involve the skin microbiome. We also review the unique biochemistry of human sebaceous glands and discuss evolutionary hypotheses that may partly explain why human sebum is so unique. Finally, we discuss how sebum-derived volatiles intersect with human health and disease, for example, via attraction of disease-vector mosquitoes or use in medical diagnostics. Our review draws insights from multiple fields, which together provide surprising clarity on some of the proximate and ultimate mechanisms underlying the distinctive composition of human odor.

Identification of a higher C-S lyase activity of Staphylococcus hominis in volunteers with unpleasant axillary odour

OBJECTIVE

Excessive and unpleasant odours that emanate from the skin can induce bromhidrosis and substantially impair a person's quality of life. Enzymatic pathways generating unpleasant odours are well detailed, and among them, the C-S lyase is one of the enzymes involved in the conversion of non-volatile precursors into thiol-type malodorous volatile molecules such as 3M3SH. This study aimed to investigate the variation of axillary odour intensity correlated with Staphylococcus (S.) hominis C-S lyase activity within a group of volunteers after a physical activity.

METHODS

First, a group of 24 volunteers from the same ethnicity with standardized hygienic and alimentary practices participated in a supervised indoor cycling activity. Following this session, worn T-shirts were recovered to enable the olfactory evaluation of axillary odours by qualified experts. To go further, the microbiota from the axillary zone of each volunteer was sampled and the bacterial relative abundance was investigated by using 16S rRNA metasequencing. Then, S. hominis isolates were obtained by culturomics from these microbiota samples and the C-S lyase activity was measured by spectrofluorometry in protein crude extracts.

RESULTS

The evaluation of the odour intensity revealed that within the panel, two groups were significantly distinct. A non-odorous group and a malodorous one with volunteers having unpleasant odours. The 16S rRNA metasequencing reveals differences in bacterial communities between the two groups with a significant increase in the relative abundance of S. hominis in the malodorous group compared with the non-odorous one. The C-S lyase activities measured on S. hominis sampled on volunteers from the two groups demonstrate that for an equivalent quantity of protein, this enzymatic activity is significantly higher for the samples originating from the malodorous group.

CONCLUSION

Hence, this study demonstrates that beyond the increase of S. hominis relative abundance, the C-S lyase enzymatic activity of this bacteria is also higher in volunteers with unpleasant axillary odours.

Deodorants and antiperspirants: New trends in their active agents and testing methods

Sweating is the human body's thermoregulation system but also results in unpleasant body odour which can diminish the self-confidence of people. There has been continued research in finding solutions to reduce both sweating and body odour. Sweating is a result of increased sweat flow and malodour results from certain bacteria and ecological factors such as eating habits. Research on deodorant development focuses on inhibiting the growth of malodour-forming bacteria using antimicrobial agents, whereas research on antiperspirant synthesis focuses on technologies reducing the sweat flow, which not only reduces body odour but also improves people's appearance. Antiperspirant's technology is based on the use of aluminium salts which can form a gel plug at sweat pores, obstructing the sweat fluid from arising onto the skin surface. In this paper, we perform a systematic review on the recent progress in the development of novel antiperspirant and deodorant active ingredients that are alcohol-free, paraben-free, and naturally derived. Several studies have been reported on the alternative class of actives that can potentially be used for antiperspirant and body odour treatment including deodorizing fabric, bacterial, and plant extracts. However, a significant challenge is to understand how the gel-plugs of antiperspirant actives are formed in sweat pores and how to deliver long-lasting antiperspirant and deodorant benefits.

Cutaneous Hormone Production Is Distinct between Anatomical Sites and between Males and Females

The skin acts as an endocrine organ capable of hormone production and response. Moreover, many skin conditions clinically improve with antiandrogen therapies. Despite their importance, we have an incomplete understanding of the composition of hormones produced by the skin. In this study, we have characterized the hormonal landscape of the skin across anatomical sites and between the sexes through analysis of skin secretions. In this observational pilot study, we collected skin secretions from the antecubital fossa, forehead, back, and axilla of 12 male and 10 female subjects using commercially available adhesive patches. We then developed a method to extract and quantify hormones from these secretions through liquid chromatography-tandem mass spectrometry. We were able to detect seven hormones and observed anatomical site differences in glucocorticoids, cortisone, and 11-deoxycorticosterone. Most notably, we observed marked elevations in dehydroepiandrosterone in the axilla and androstenedione on the forehead. We also detected differences in several sex steroid hormones between male and female subjects, with the majority consistent with known systemic hormone differences. Through this approach, future studies will determine how hormonal composition of skin secretions is altered in skin diseases.

Using the Hair Removal Laser in the Axillary Region and its Effect on Normal Microbial Flora

Introduction: The axillary hair removal laser is one of the most often used procedures to treat unwanted hairs in that region. Employing this technology can be helpful in decreasing the bromhidrosis. Methods: In the present research, a clinical trial study over the effect of the hair removal laser on normal microbial flora at the axillary region is presented. The intervention group consisted of 30 women referred to the dermatologic clinic for the purpose of removing axillary hair by the alexandrite 755 nm laser and the control group consisted of 30 women referred to the same clinic for any other reasons. Both groups were evaluated for the type of bacterial strains on the first visit and after three and six months. Results: The results showed that the sense of sweat smell improved by about 63% after the last laser session. The frequency of all bacterial strains decreased in the intervention group except Staphylococcus epidermidis which was significant. In the control group, there was no significant decrement in any bacterial strains and even the prevalence of more strains including Staphylococcus aureus and S. epidermidis increased. Counting the mean bacterial colon showed a slight decrement of the bacterial count following the laser. Conclusion: The use of laser radiation, even with the aim of hair removal, can alter the microbial flora, and it can be accompanied by the improvement of the smell of sweat. The effect of the laser on different bacterial strains is quite different, which can depend on the amount of energy, the wavelength, the characteristics of the area under the laser, and also the structural properties of the membrane of the microorganism itself.

Flexible, low volume detection of chronobiology biomarkers from human sweat

The work demonstrates the development of a chronobiology tracking system using an affinity-based electrochemical detection modality. This serpentine electrode based system is non-invasive, label free, and economical enabling passive sweat tracking.

Stable Antimicrobial Activity Achieved via Immobilization of Quaternary Ammonium Chloride on Hair

　Dandruff and underarm malodor are caused by microorganisms. Personal hygiene products that contain various types of antimicrobial agents are available and are used for the prevention and alleviation of these conditions. However, their effects are not significant and often do not last long. Working toward a solution, hair was treated with thioglycolic acid, a reducing agent, and then with [2-(acryloyloxy)ethyl] trimethylammonium chloride to covalently bond and immobilize quaternary ammonium chloride (QAC) to hair shafts. Fourier transform infrared analysis confirmed the bonding of QAC. Time-kill assays were performed to evaluate the antimicrobial activities against two yeast strains responsible for dandruff, two bacterial strains responsible for underarm malodor, and two typical bacterial skin microflora strains. The time- kill assays revealed the antimicrobial effects of QAC against all tested microorganisms. Washing with detergents decreased the antimicrobial effects compared to hair not washed with detergent. This method could potentially replace personal hygiene products, such as shampoos and antiperspirants, which act as antimicrobial agents in the prevention and alleviation of dandruff and underarm malodor.

Medical ovariectomy in menopausal breast cancer patients with high testosterone levels: a further step toward tailored therapy

Five years of adjuvant therapy with anti-estrogens reduce the incidence of disease progression by about 50% in estrogen receptor-positive breast cancer patients, but late relapse can still occur after anti-estrogens have been discontinued. In these patients, excessive androgen production may account for renewed excessive estrogen formation and increased risks of late relapse. In the 50% of patients who do not benefit with anti-estrogens, the effect of therapy is limited by de novo or acquired resistance to treatment. Androgen receptor and epidermal growth factor receptor overexpression are recognized mechanisms of endocrine resistance suggesting the involvement of androgens as activators of the androgen receptor pathway and as stimulators of epidermal growth factor synthesis and function. Data from a series of prospective studies on operable breast cancer patients, showing high serum testosterone levels are associated to increased risk of recurrence, provide further support to a role for androgens in breast cancer progression. According to the above reported evidence, we proposed to counteract excessive androgen production in the adjuvant setting of estrogen receptor-positive patients and suggested selecting postmenopausal patients with elevated levels of serum testosterone, marker of ovarian hyperandrogenemia, for adjuvant treatment with a gonadotropins-releasing hormone analogue (medical oophorectomy) in addition to standard therapy with anti-estrogens. The proposed approach provides an attempt of personalized medicine that needs to be further investigated in clinical trials.

Effective axillary malodour reduction by polyquaternium-16-containing deodorants

OBJECTIVE

Worldwide, individuals apply deodorants to combat malodour formation originating from the axillary vault. Considering the globally increasing demand for efficacious, safe deodorants, we investigated the antimicrobial effectiveness of a polymeric quaternary ammonium compound (PQ-16) as a new active in a roll-on formulation against microbial growth and axillary malodour.

METHODS

We utilized an in vivo microbiological assessment to determine antimicrobial effects of the PQ-16-containing deodorant formulation (DEO1) (i) in comparison with a commercially available deodorant roll-on claiming a 24-h protection against body odour (DEO2) and (ii) in comparison with a roll-on containing the same formulation as DEO1 but comprising aluminium chlorohydrate instead of PQ-16 (DEO3) 1, 4, 8, 24 and 48 h after treatment. Also, the axillary malodour intensity 24 and 48 h after application of deodorants was investigated in a controlled in vivo study performed by a trained sniffer panel using direct sniffing.

RESULTS

Treatment with DEO1 in comparison with application of DEO2 significantly reduced the log 10 bacterial count at all points in time. After 24 and 48 h, sniffers rated malodour production in the DEO1-treated axillae significantly lower than in the DEO2-treated armpits. Application of DEO1 in comparison with DEO3 decreased the log 10 bacterial count after 1, 4, 8 and 24 h (significant for 4 and 8 h). After 48 h, the log 10 bacterial count showed similar values for both DEO1 and DEO3. The sniffer panel reported no significant differences between axillary malodour in DEO1-treated compared to DEO3-treated armpits after 24 and 48 h.

CONCLUSION

We identified polyquaternium-16 (PQ-16, copolymers of 1-vinyl-2-pyrrolidone and 1-vinyl-3-methylimidazolium chloride) as a highly effective deodorant active. Results showed that a newly developed PQ-16-containing deodorant roll-on formulation (i) significantly reduced axillary malodour 24 and 48 h after treatment, (ii) significantly decreased the amount of axillary bacteria, (iii) compared to a commercially available deodorant claiming a 24-h odour protection significantly lowered axillary malodour 24 h and 48 h after application, and (iv) was well tolerated by the study population. PQ-16 represents an innovative and skin-friendly deodorant active.

The Effect of Ethnicity on Human Axillary Odorant Production

Previous findings from our laboratory highlighted marked ethnic differences in volatile organic compounds (VOCs) from cerumen among individuals of Caucasian, East Asian, and African-American descent, based, in part, on genetic differences in a gene that codes for a transport protein, which is a member of the ATP-binding cassette transporter, sub-family C, member 11 (ABCC11). In the current work, we hypothesized that axillary odorants produced by East Asians would differ markedly from those obtained from individuals of European or African descent based on the pattern of ethnic diversity that exists in ABCC11. Using gas chromatography/mass spectrometry (GC/MS) we examined differences in axillary odorant VOCs among 30 individuals of African-American, Caucasian, and East Asian descent with respect to their ABCC11 genotype. While no qualitative differences in the type of axillary odorants were observed across ethnic groups, we found that characteristic axillary odorants varied quantitatively with respect to ethnic origin. We propose that ABCC11 is not solely responsible for predicting the relative amounts of volatiles found in axillary secretions and that other biochemical pathways must be involved.

Butane-2,3-dione: the key contributor to axillary and foot odor associated with an acidic note

Human body odor, which contains several volatile organic compounds, possesses various odor qualities. To identify key volatile compounds responsible for the common unpleasant odors derived from human axillae and feet, the odor quality and intensity of 118 human axillae and feet were directly evaluated by sniffing, and odor compounds obtained from the subjects were identified. Furthermore, the sensory differences in odor intensity and quality with and without addition of butane-2,3-dione were evaluated by using the visual analog scale (VAS). An acidic odor was a common unpleasant note in human axillae and feet. Butane-2,3-dione was identified as a key compound associated with this odor. Strong positive correlations between the amount of butane-2,3-dione, and the odor intensities of axillae and feet were observed, and the addition of butane-2,3-dione solution to blended short-chain fatty-acid solutions caused significantly increased VAS values of axillary-like odor, unpleasantness, and odor intensity compared to those of each solution without added butane-2,3-dione.

Glutathione-conjugated sulfanylalkanols are substrates for ABCC11 and γ-glutamyl transferase 1: a potential new pathway for the formation of odorant precursors in the apocrine sweat gland

We have previously shown that precursors of odorous components characteristic of axillary sweat are hardly detectable or undetectable in individuals carrying the 538G > A SNP in the ABCC11 transporter gene. However, it is unclear, whether ABCC11 is directly involved in the transport of these compounds. To approach this question, transport of peptide-conjugated potential precursors of 3-methyl-3-sulfanylhexanol (3M3SH), a key determinant of axillary malodour, was measured using membrane vesicles of Sf9 insect cells overexpressing human ABCC11. Whilst no ABCC11-mediated transport was detected for the dipeptide precursor Cys-Gly-3M3SH, the glutathione conjugate of 3M3SH (SG-3M3SH) was robustly taken up by ABCC11 at a transport rate of 0.47 pmol/mg/min. Collectively, these results illuminate SG-3M3SH as a putative precursor of 3M3SH, which then may undergo intra-vesicular maturation to generate Cys-Gly-3M3SH. Critically, the apocrine sweat gland was demonstrated to express γ-glutamyl transferase 1 (GGT1) protein, which is known to catalyse the deglutamylation of glutathionyl conjugates. Additionally, we provide evidence that recombinant and isolated hepatic human GGT1 is capable of transforming SG-3M3SH to Cys-Gly-3M3SH in vitro. To sum up, we demonstrate that the functionality of ABCC11 is likely to play an important role in the generation of axillary malodour. Furthermore, we identify GGT1 as a key enzyme involved in the biosynthesis of Cys-Gly-3M3SH.

Identification of volatile organic compounds in human cerumen

We report here the initial examination of volatile organic compounds (VOCs) emanating from human earwax (cerumen). Recent studies link a single nucleotide polymorphism (SNP) in the adenosine triphosphate (ATP) binding cassette, sub-family C, member 11 gene (ABCC11) to the production of different types of axillary odorants and cerumen. ABCC11 encodes an ATP-driven efflux pump protein that plays an important function in ceruminous apocrine glands of the auditory canal and the secretion of axillary odor precursors. The type of cerumen and underarm odor produced by East Asians differ markedly from that produced by non-Asians. In this initial report we find that both groups emit many of the same VOCs but differ significantly in the amounts produced. The principal odorants are volatile organic C2-to-C6 acids. The physical appearance of cerumen from the two groups also matches previously reported ethnic differences, viz., cerumen from East Asians appears dry and white while that from non-Asians is typically wet and yellowish-brown.

Biomonitoring of human fetal exposure to environmental chemicals in early pregnancy

The first trimester of human fetal life, a period of extremely rapid development of physiological systems, represents the most rapid growth phase in human life. Interference in the establishment of organ systems may result in abnormal development that may be manifest immediately or programmed for later abnormal function. Exposure to environmental chemicals may be affecting development at these early stages, and yet there is limited knowledge of the quantities and identities of the chemicals to which the fetus is exposed during early pregnancy. Clearly, opportunities for assessing fetal chemical exposure directly are extremely limited. Hence, this review describes indirect means of assessing fetal exposure in early pregnancy to chemicals that are considered disrupters of development. Consideration is given to such matrices as maternal hair, fingernails, urine, saliva, sweat, breast milk, amniotic fluid and blood, and fetal matrices such as cord blood, cord tissue, meconium, placenta, and fetal liver. More than 150 articles that presented data from chemical analysis of human maternal and fetal tissues and fluids were reviewed. Priority was given to articles where chemical analysis was conducted in more than one matrix. Where correlations between maternal and fetal matrices were determined, these articles were included and are highlighted, as these may provide the basis for future investigations of early fetal exposure. The determination of fetal chemical exposure, at the time of rapid human growth and development, will greatly assist regulatory agencies in risk assessments and establishment of advisories for risk management concerning environmental chemicals.

Analysis of characteristic human female axillary odors: Qualitative comparison to males

Odors produced in the human female axillae are of both biological and commercial importance. Several studies have suggested that extracts from female underarm secretions can alter the length and timing of the female menstrual cycle. In addition, more than 1.6 billion dollars are spent annually on products to eliminate or mask the axillary odors. Our recent studies have determined that the characteristic axillary odors in males consist of C6-C11, saturated, unsaturated and branched acids, with (E)-3-methyl-2-hexenoic acid (3M2H) being the major compound in this mixture. The 3M2H appears to be carried to the skin surface bound to two proteins in the axillary secretions. Data reported here show that the same mixture of odorous compounds is found in female axillary secretions, with several minor qualitative differences. Separation of the female apocrine secretions into aqueous and organic soluble fractions demonstrated that 3M2H, and several other members of the acids in the characteristic odor, are released by hydrolysis with base. Electrophoretic separation of the proteins found in the aqueous phase of female apocrine secretions revealed a pattern identical to that seen in males. The qualitative similarity of the acidic constituents making up the characteristic axillary odors of both females and males as well as the proteins present in the aqueous phase suggest a similar origin for axillary odors in both sexes.

Efficient sweat reduction of three different antiperspirant application forms during stress-induced sweating

OBJECTIVES

Stress sweating can occur in everyday situations independently of thermally-induced perspiration. It is triggered by emotionally challenging situations and leads to underarm wetness and a characteristic unpleasant malodor. In this study, we aimed to determine the long-term efficacy of three unperfumed antiperspirant (AP) formulas for different application forms (roll-on, stick, aerosol) against stress-induced sweating and malodor formation.

METHODS

We utilized the widely accepted Trier Social Stress Test (TSST) to induce psychosocial stress in female and male volunteers (18 - 40 years) and determined physiological stress parameters. To additionally assess the efficacy of the test AP roll-on against thermally-induced sweating, a hot room study was performed.

RESULTS

Increasing heart rates and an augmentation of saliva cortisol levels during the TSST indicated a substantial stress reaction which was paralleled by a pronounced sweat production in the untreated axillae of both males and females. Forty-eight hours after application, all three test APs significantly decreased the amount of sweat in the treated axillae independent of gender. With respect to AP effects on malodor production, trained sniffers assessed sweat samples collected during the TSST from the untreated axillae as significantly more malodorous than comparable samples from the AP-treated axillae. Also, independent of gender the test AP roll-on significantly decreased the thermally-induced sweat in the AP-treated axilla.

CONCLUSION

We show for the first time a highly effective reduction of emotionally-induced axillary sweating and malodor production for three different application forms 48 h after the last product use. The specially developed roll-on, stick, and aerosol AP provide long-term protection against stress-induced sweat which is of high relevance in everyday life.

Pharmacogenetics of human ABC transporter ABCC11: new insights into apocrine gland growth and metabolite secretion

Cell secretion is an important physiological process that ensures smooth metabolic activities and tissue repair as well as growth and immunological functions in the body. Apocrine secretion occurs when the secretory process is accomplished with a partial loss of cell cytoplasm. The secretory materials are contained within secretory vesicles and are released during secretion as cytoplasmic fragments into the glandular lumen or interstitial space. The recent finding that the non-synonymous single nucleotide polymorphisms (SNP) 538G > A (rs17822931; Gly180Arg) in the ABCC11 gene determines the type of earwax in humans has shed light on the novel function of this ABC (ATP-binding cassette) transporter in apocrine glands. The wild-type (Gly180) of ABCC11 is associated with wet-type earwax, axillary osmidrosis, and colostrum secretion from the mammary gland as well as the potential risk of mastopathy. Furthermore, the SNP (538G > A) in the ABCC11 gene is suggested to be a clinical biomarker for the prediction of chemotherapeutic efficacy. The aim of this review article is to provide an overview on the discovery and characterization of genetic polymorphisms in the human ABCC11 gene and to explain the impact of ABCC11 538G > A on the apocrine phenotype as well as the anthropological aspect of this SNP in the ABCC11 gene and patients’ response to nucleoside-based chemotherapy.

Adrenarche and middle childhood

Middle childhood, the period from 6 to 12 years of age, is defined socially by increasing autonomy and emotional regulation, somatically by the development of anatomical structures for subsistence, and endocrinologically by adrenarche, the adrenal production of dehydroepiandrosterone (DHEA). Here I suggest that DHEA plays a key role in the coordinated development of the brain and body beginning with middle childhood, via energetic allocation. I argue that with adrenarche, increasing levels of circulating DHEA act to down-regulate the release of glucose into circulation and hence limit the supply of glucose which is needed by the brain for synaptogenesis. Furthermore, I suggest the antioxidant properties of DHEA may be important in maintaining synaptic plasticity throughout middle childhood within slow-developing areas of the cortex, including the insula, thamalus, and anterior cingulate cortex. In addition, DHEA may play a role in the development of body odor as a reliable social signal of behavioral changes associated with middle childhood.

Composition of fingermark residue: a qualitative and quantitative review

This article describes the composition of fingermark residue as being a complex system with numerous compounds coming from different sources and evolving over time from the initial composition (corresponding to the composition right after deposition) to the aged composition (corresponding to the evolution of the initial composition over time). This complex system will additionally vary due to effects of numerous influence factors grouped in five different classes: the donor characteristics, the deposition conditions, the substrate nature, the environmental conditions and the applied enhancement techniques. The initial and aged compositions as well as the influence factors are thus considered in this article to provide a qualitative and quantitative review of all compounds identified in fingermark residue up to now. The analytical techniques used to obtain these data are also enumerated. This review highlights the fact that despite the numerous analytical processes that have already been proposed and tested to elucidate fingermark composition, advanced knowledge is still missing. Thus, there is a real need to conduct future research on the composition of fingermark residue, focusing particularly on quantitative measurements, aging kinetics and effects of influence factors. The results of future research are particularly important for advances in fingermark enhancement and dating technique developments.

Pharmacogenomics of human ABC transporter ABCC11 (MRP8): potential risk of breast cancer and chemotherapy failure

Some genetic polymorphisms of human ABC transporter genes are reportedly related to the risk of certain diseases and patients’ responses to medication. Human ABCC11 functions as an ATP-dependent efflux pump for amphipathic anions. One non-synonymous SNP 538G>A (Gly180Arg) has been found to greatly affect the function and stability of de novo synthesized ABCC11 (Arg180) variant protein. The SNP variant lacking N-linked glycosylation is recognized as a misfolded protein in the endoplasmic reticulum (ER) and readily undergoes proteasomal degradation. This ER-associated degradation of ABCC11 protein underlies the molecular mechanism of affecting the function of apocrine glands. On the other hand, the wild type (Gly180) of ABCC11 is associated with wettype earwax, axillary osmidrosis, colostrum secretion from the mammary gland, and the potential susceptibility of breast cancer. Furthermore, the wild type of ABCC11 reportedly has ability to efflux cyclic nucleotides and nucleoside-based anticancer drugs. The SNP (538G>A) of the ABCC11 gene is suggested to be a clinical biomarker for prediction of chemotherapeutic efficacy. Major obstacle to the successful chemotherapy of human cancer is development of resistance, and nucleoside-based chemotherapy is often characterized by inter-individual variability. This review provides an overview about the discovery and the genetic polymorphisms in human ABCC11. Furthermore, we focus on the impact of ABCC11 538G>A on the apocrine phenotype, patients’ response to nucleoside-based chemotherapy, and the potential risk of breast cancer.

Molecular basis of human body odour formation: insights deduced from corynebacterial genome sequences

During the past few decades, there has been an increased interest in the essential role of commensal skin bacteria in human body odour formation. It is now generally accepted that skin bacteria cause body odour by biotransformation of sweat components secreted in the human axillae. Especially, aerobic corynebacteria have been shown to contribute strongly to axillary malodour, whereas other human skin residents seem to have little influence. Analysis of odoriferous sweat components has shown that the major odour-causing substances in human sweat include steroid derivatives, short volatile branched-chain fatty acids and sulphanylalkanols. In this mini-review, we describe the molecular basis of the four most extensively studied routes of human body odour formation, while focusing on the underlying enzymatic processes. Considering the previously reported role of β-oxidation in odour formation, we analysed the genetic repertoire of eight Corynebacterium species concerning fatty acid metabolism. We particularly focused on the metabolic abilities of the lipophilic axillary isolate Corynebacterium jeikeium K411.

Body malodours and their topical treatment agents

Body malodour, including foot odour, suppresses social interaction by diminishing self-confidence and accelerating damage to the wearer's clothes and shoes. Most treatment agents, including aluminium anti-perspirant salts, inhibit the growth of malodourous bacteria. These metallic salts also reduce sweat by blocking the excretory ducts of sweat glands, minimizing the water source that supports bacterial growth. However, there are some drawback effects that limit the use of aluminium anti-perspirant salts. In addition, over-the-counter anti-perspirant and deodourant products may not be sufficiently effective for heavy sweaters, and strong malodour producers. Body odour treatment agents are rarely mentioned in the literature compared with other cosmetic ingredients. This review briefly summarizes the relationship among sweat, skin bacteria, and body odour; describes how odourous acids, thiols, and steroids are formed; and discusses the active ingredients, including metallic salts and herbs, that are used to treat body odour. A new class of ingredients that function by regulating the release of malodourants will also be described. These ingredients do not alter the balance of the skin flora.

A short history of sweat gland biology

The axilla, especially its microflora and axillary sweat glands as well as their secretions, is the main target of cosmetic compositions such as deodorants or antiperspirants. There are three types of sweat glands present in the axillary skin, namely apocrine, eccrine and apoeccrine sweat glands. Here, we provide an overview of the morphological, structural and functional characteristics of the different gland types and present techniques that allow their clear distinction. Moreover, we describe different forms of perspiration as physical reactions to external and internal stimuli.

Genetic influences on human body odor: from genes to the axillae

Several groups have identified the characteristic axillary odorants and how they arrive on the skin surface, pre-formed, bound to water-soluble odorless precursors in apocrine secretions. In the current issue, Martin et al., (2010) describe the relationship between the production of axillary odorants and variants in the ABCC11 gene. Individuals who are homozygotic for a SNP (538G>A) were found to have significantly less of the characteristic axillary odorants than either individuals who were heterozygotic for this change or those who had the wild-type gene. The 538G>A SNP predominates in Asians who have nearly complete loss of typical body odor. ABCC11 is expressed and localized in apocrine sweat glands. These findings are remarkably similar to the ethnic distribution and expression patterns for apocrine apoD, a previously identified carrier of a characteristic axillary odorant.

Current issues in the study of androstenes in human chemosignaling

We review research on the 16-androstenes and their special claim, born originally of the finding that androstenes function as boar pheromones, to be human chemosignals. Microbial fauna in human axillae act upon the 16-androstenes to produce odorous volatiles. Both individual variation and sex differences in perception of these odors suggest that they may play a role in mediating social behavior, and there is now much evidence that they modulate changes in interpersonal perception, and individual mood, behavior, and physiology. Many of these changes are sensitive to the context in which the compounds are experienced. However, many key outstanding questions remain. These include identification of the key active compounds, better quantification of naturally occurring concentrations and understanding how experimentally administered concentrations elicit realistic effects, and elucidation of individual differences (e.g., sex differences) in production rates. Until such issues are addressed, the question of whether the androstenes play a special role in human interactions will remain unresolved.

A functional ABCC11 allele is essential in the biochemical formation of human axillary odor

The characteristic human axillary odor is formed by bacterial action on odor precursors that originate from apocrine sweat glands. Caucasians and Africans possess a strong axillary odor ,whereas many Asians have only a faint acidic odor. In this study, we provide evidence that the gene ABCC11 (MRP8), which encodes an apical efflux pump, is crucial for the formation of the characteristic axillary odor and that a single-nucleotide polymorphism (SNP) 538G --> A, which is prominent among Asian people, leads to a nearly complete loss of the typical odor components in axillary sweat. The secretion of amino-acid conjugates of human-specific odorants is abolished in homozygotic carriers of the SNP, and steroidal odorants and their putative precursors are significantly reduced. Moreover, we show that ABCC11 is expressed and localized in apocrine sweat glands. These data point to a key function of ABCC11 in the secretion of odorants and their precursors from apocrine sweat glands. SNP 538G --> A, which also determines human earwax type, is present on an extended haplotype, which has reached >95% frequency in certain populations in recent human evolution. A strong positive selection in mate choice for low-odorant partners with a dysfunctional ABCC11 gene seems a plausible explanation for this striking frequency of a loss-of-function allele.

Apocrine sweat gland obstruction by antiperspirants allowing transdermal absorption of cutaneous generated hormones and pheromones as a link to the observed incidence rates of breast and prostate cancer in the 20th century

Breast and prostate cancer share similarities and likely represent homologous cancers in females and males, respectively. The role of hormones such as testosterone and estrogen in carcinogenesis is well established. Despite worldwide research efforts, the pathogenesis of these diseases is largely not well understood. Personal care products containing estrogens or xenoestrogens have raised concern as a breast cancer risk, especially in young African-American women. In the United States (US) there is a parallel rise in the incidence in breast and prostate cancer compared to selected non-hormone dependent tumors. Observed US and global breast and prostate cancer incidence increases were occurring before exogenous hormone replacement and xenoestrogen exposure were commonplace. An unintentional, inadvertent, and long term hormone exposure may occur from transdermal absorption of sex hormones and pheromones (androgens) from axillary apocrine sweat gland obstruction by aluminum-based antiperspirants. The global rise in antiperspirant use parallels rises in breast and prostate cancer incidence and mortality rates. A multi-disciplinary literature based set of evidence is presented on how such a link is possible, to prompt confirmatory investigations in the pursuit of unmet needs in breast and prostate cancer etiology and prevention.

Sexual differentiation in sensitivity to male body odor(1)

We have confirmed that more female subjects than male subjects evaluate male body odor as significantly unpleasant. Through an investigation on sexual differentiation in sensitivity to male body odor, we concluded that one of the volatile steroids, androstenone, had two effects on female olfactory sense. First, female subjects perceived androstenone itself to be more unpleasant than male subjects. Second, for only female subjects, androstenone, at a concentration of one-tenth of detection threshold, enhanced the intensity and unpleasantness of body-odor constituents such as short-chain fatty acids.

Production of malodorous steroids from androsta-5,16-dienes and androsta-4,16-dienes by Corynebacteria and other human axillary bacteria

The biotransformations of a number of steroids, chiefly 5,6,16,17-tetradehydro-androstanes, are reported. The strains investigated were Corynebacteria sp. G38, G40, G41, B, Brevis sp. CW5 and Micrococcus sp. M-DH2. Corynebacterium sp. G41 proved remarkably efficient in effecting oxidative isomerisation of 5-ene-3-sterols into the corresponding 4-en-3-ones. The main biochemical reactions involved were oxidation at C-3; no reduction processes were observed. Conversions of 3beta-sterols into the C-3 oxo-steroids were high, but were correspondingly low for the 3alpha-sterol epimers. Androsta-4,16-dien-3-one and 5beta-androsta-16-en-3-one are crucial to the formation of malodour. The rate of formation of these compounds was measured over 72 h incubation periods using three substrates: androsta-5,16-dien-3beta-ol, androsta-4,16-dien-3beta-ol and androsta-5,16-dien-3-one. Induction studies of the transformation of the androsta-5,16-dien-3beta-ol into the very odorous compound androsta-4,16-dien-3-one showed that cells incubated with a mixture of antibiotics displayed the same extent of biotransformation as normal cells if the concentration of antibiotic was low (1, 3, 5 and 7 microg/ml), although at concentrations higher than 10 microg/ml, biotransformation yields were reduced. Pre-incubation with a 3beta-fluoro-steroid inhibited the formation of the odorous androsta-4,16-dien-3-one.

Headspace solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) for the determination of 5alpha-androst-2-en-17-one and -17beta-ol in the female Asian elephant: application for reproductive monitoring and prediction of parturition

Asian elephants are not self-sustaining in captivity. The main reasons for this phenomenon are a low birth rate, an aging population, and poor calf-rearing. Therefore, it is essential that reproductive rates had to be improved and there is need for rapid quantitative measures to monitor reproductive functions focussing on estrous detection and the prediction of the period of parturition. The objective of this study was to develop a method which combines headspace solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) for analyses of 5alpha-androst-2-en-17beta-ol and -17-one to prognose estrous and to predict the period of parturition. SPME was carried out with a CTC Combi Pal system. The course of the luteal phase-specific substance 5alpha-androst-2-en-17beta-ol and -17-one followed a cyclic pattern in which the follicular and luteal phases could be clearly distinguished (mean estrous cycle length, 15+/-1.4 weeks). Based on daily urine samples, estrous prognosis might be possibly based on the initial 5alpha-androst-2-en-17beta-o1 increase at the end of the follicular phase. Parturition prognosis was performed in three elephant cows based on the 5alpha-androst-2-en-17beta-o1 drop to baseline levels 5-4 days prior parturition. Experiments revealed that 5alpha-androst-3alpha-ol-17-one and probably 5alpha-androst-3alpha-ol-17beta-ol are generated from sulfate conjugates by a thermal process.

Capillary gas chromatography with chemical ionization negative ion mass spectrometry in the identification of odorous steroids formed in metabolic studies of the sulphates of androsterone, DHA and 5alpha-androst-16-en-3beta-ol with human axillary bacterial isolates

The products of metabolism of the sulphates (0.5 micromol/l) of androsterone, dehydroepiandrosterone (DHA) and 5alpha-androst-16-en-3beta-ol have been investigated after incubation with 72 h cultures of human axillary bacterial isolates for 3 days at 37 degrees C. The medium used, tryptone soya broth (TSB), contained yeast extract and Tween 80. The isolates used were Coryneform F1 (known previously to metabolize testosterone and to be involved in under-arm odour (UAO) production, i.e. UAO +ve), Coryneform F46 (inactive in both the testosterone metabolism and UAO tests, i.e. UAO -ve) and Staphylococcus hominis/epidermidis (IIR3). Control incubations of TSB alone, TSB plus each of the steroid sulphates and TSB plus each of the bacterial isolates were also set up. After termination of reactions and addition of internal standards, 5alpha-androstan-3beta-ol and 5alpha-androstan-3-one (50 ng each), extracted and purified metabolites were subjected to combined gas chromatography-mass spectrometry with specific ion monitoring. Steroidal ketones were derivatized as their O-pentafluorobenzyl oximes; steroidal alcohols (only androst-16-enols in this study) were derivatized as their tert-butyldimethylsilyl ethers. Analysis was achieved by negative ion chemical ionization mass spectrometry for the pentafluorobenzyl oximes at [M-20]- and electron impact positive ion mass spectrometry for the tert-butyldimethylsilyl ethers at [M-57]+. The incubation broth contained two compounds which had gas chromatographic and mass spectrometric properties identical to those of DHA and 4-androstenedione. It was not possible, therefore, to show unequivocally that DHA sulphate (DHAS) was converted microbially into DHA, although this is implied by the finding of small quantities of testosterone and 5alpha-dihydrotestosterone in incubations with F1. With androsterone S, no free androsterone was recorded and only very small (5 pg or less) amounts of testosterone. Two odorous steroids, androsta-4,16-dien-3-one and 5alpha-androst-2-en-17-one (Steroid I) were formed (mean quantities 40 and 45 pg, respectively). The sulphate of 5alpha-androst-16-en-3beta-ol was metabolized with F1 into large quantities of the odorous steroids, 5alpha-androst-16-en-3-one and Steroid I. In addition, much smaller quantities of androsta-4,16-dien-3-one were formed. In contrast, incubations of DHAS with F46 resulted in no metabolites except, possibly, DHA, but the sulphate moiety of androsterone S was also cleaved to yield the free steroid together with large amounts of Steroid I. In incubations of DHAS and androsterone S with F1, no 16-unsaturated steroids were formed, although 5alpha-androst-16-en-3beta-yl S was de-sulphated and the free steroid further metabolized. No evidence was obtained for androst-16-ene metabolism in incubations with F46. In incubations with S. hominis/epidermidis (IIR3), androsterone S was converted into androsterone and, in high yield, to Steroid I plus some 5alpha-androst-16-en-3-one. Both DHAS and androsterone S were converted into androst-16-enols. Sulphatase activity was also manifested when 5alpha-androst-16-en-3beta-yl S was utilized as substrate with IIR3, large quantities of Steroid I and 5alpha-androst-16-en-3-one being formed, together with further metabolism of androst-16-enes. In view of the fact that both DHAS and androsterone S occur in apocrine sweat, the metabolism of these endogenous substrates by human axillary bacteria to several odorous steroids may have important implications in the context of human odour formation.

Steroid biochemistry and categorization of breast cyst fluid: relation to breast cancer risk

Patients bearing macrocysts of the breast are at higher risk of later developing cancer. The fluid filling the cysts (breast cysts fluid, BCF) contains unusual amounts of steroid conjugates, first androgen and estrogen sulfates. Measuring BCF cations (K+,Na+) allows categorization of cysts into two major subsets (type I and type II) that are associated with a different degree and/or turnover of apocrine metaplastic cells in the lining epithelium. Type I cysts (high K+/Na+ ratio) accumulate hugh amounts of dehydroepiandrosterone sulfate, estrone sulfate, androstane-3 alpha,17 beta-diol glucuronide, androsterone glucuronide and contain more testosterone and dihydrotestosterone than type II. Conversely, type II cysts (low K+/Na+ ratio) contain more progesterone and pregnenolone. A cohort study was started in 1983 at the Cancer Prevention Center, Ravenna, Italy, with the aim of evaluating the relationships between the biochemistry of BCF and the incidence of breast cancer in women with gross cystic disease (GCD) of the breast. The bimodal distribution of the cationic pattern has been confirmed from data obtained in 798 patients aspirated. The risk of cyst relapse was significantly higher among women with type I cysts or with multiple cysts at presentation. Twelve incident cases of breast cancer have been diagnosed among women whose BCF was categorized. Eleven out of 12 cases had type I or multiple cysts. The cumulative incidence of breast cancer among patients bearing type I cysts was 2.5%. We conclude that women with GCD bearing type I cysts have an increased breast cancer risk when compared with the counterpart bearing type II cysts or the general population.

Comparison of 16-androstene steroid concentrations in sterile apocrine sweat and axillary secretions: interconversions of 16-androstenes by the axillary microflora--a mechanism for axillary odour production in man?

The concentrations of five 16-androstene steroids were determined, by a GC-MS method, in freshly-produced apocrine sweat (adrenaline-induced), in 8 men and 2 women. The ranges of concentrations (nmol/microliter) in apocrine sweat were: 5 alpha-androst-16-en-3-one (5 alpha-A), 0.1-2.0 and 4,16-androstadien-3-one (androstadienone), 0-1.9, 5,16-Androstadien-3 beta-ol (androstadienol) was also found in 5 of the subjects (range 0.05-1.05). 5 alpha-Androst-16-en-3 alpha- or 3 beta-ols [3 alpha (beta)-androstenols] were only found in small amounts (< 0.1 nmol/microliters) in a few subjects. In the second study, prior to apocrine sweat collection (adrenaline injection), the axillary skin of 6 of the male subjects was washed with diethyl ether on an adjacent site of the axillary vault. The concentrations of 16-androstenes were compared in the ethereal extracts and apocrine sweat. The former contained detectable levels (pmol/cm2) of androstadienone (17.9 +/- 2.4), 3 alpha-androstenol (6.9 +/- 3.7), 3 beta-androstenol (1.8 +/- 1.0) and androstadienol (1.9 +/- 0.5) (means +/- SEM) in all 6 subjects. All but 1 subject also had 5 alpha-androstenone, the mean value for the others being 2.5 +/- 0.6. The axillary skin levels of 3 alpha- and 3 beta-androstenols, androstadienol and, in 3 subjects, androstadienone exceeded those in the apocrine sweat obtained from the same subjects, whereas levels of 5 alpha-androstenone in the skin extracts were all lower than in apocrine sweat samples, when related to the corresponding areas of skin sampled. The metabolism of 16-androstenes was studied in vitro in the presence of two aerobic coryneform bacteria, previously shown to metabolize testosterone as well as being capable of producing odour from extracts of axillary sweat in an odour-generation test. Although both coryneforms caused complex metabolic reactions and were capable of oxidation or reduction at C-3 and C-4, the overall direction favoured reduction. For example, large quantities of the more odorous 5 alpha-androstenone and 3 alpha-androstenol were formed from androstadienol and androstadienone. In contrast, strains of corynebacteria, unable to produce odour and incapable of metabolizing testosterone, were also unable to metabolize 16-androstenes.(ABSTRACT TRUNCATED AT 400 WORDS)

Biochemical study of cyst fluid in human breast cystic disease: a review

Gross cystic disease of the breast may sometimes indicate an increased risk of breast cancer. Biochemical analysis of the cyst fluid could suggest which cysts are associated with breast cancer risk, as well as providing insights into the pathophysiology of this condition. The Na+/K+ ratio appears to be associated with the histological classification of the cyst. Sulfoconjugated estrogens and androgens, especially DHEA-S, are often found at high levels. A number of gross cystic disease fluid proteins (GCDFPs) have been described, and several polypeptide growth factors including EGF and IGF-I are frequently found. It is hoped that biochemical analysis of these components of breast cyst fluids will shed further light on the role of gross cysts in relation to breast cancer.

Accumulation of active androgens in breast cyst fluids

80 breast cyst fluids (BCF) from 57 patients were divided by K+/Na+ ratio: 56 with ratio over 1 (type I) and 24 with ratio less than 1 (type II). Significantly higher amounts of testosterone, dihydrotestosterone and dehydroepiandrosterone sulphate (DHAS) were found in type I than in type II cysts. A positive relation was found between testosterone and dihydrotestosterone in both types. DHAS was significantly correlated with testosterone and dihydrotestosterone in type I casts only. In 52 patients, blood was sampled after cyst evacuation. Testosterone was significantly higher in blood than in BCF while dihydrotestosterone and androstenedione were significantly higher in BCF. No relation was observed between circulating levels of androgens and their intracystic concentrations. Women bearing type I cysts may be at increased risk of developing cancer. These findings support the hypothesis that androgens play a role in the hormonal aetiology of breast cancer.