Human Eccrine Glands Research Articles

Gap junction-mediated contraction of myoepithelial cells induces the peristaltic transport of sweat in human eccrine glands

Eccrine sweat glands play an essential role in regulating body temperature. Sweat is produced in the coiled secretory portion of the gland, which is surrounded by obliquely aligned myoepithelial cells; the sweat is then peristaltically transported to the skin surface. Myoepithelial cells are contractile and have been implicated in sweat transport, but how myoepithelial cells contract and transport sweat remains unexplored. Here, we perform ex vivo live imaging of an isolated human eccrine gland and demonstrate that cholinergic stimulation induces dynamic contractile motion of the coiled secretory duct that is driven by gap junction-mediated contraction of myoepithelial cells. The contraction of the secretory duct occurs segmentally, and it is most prominent in the region surrounded by nerve fibers, followed by distension-contraction sequences of the excretory duct. Overall, our ex vivo live imaging approach provides evidence of the contractile function of myoepithelial cells in peristaltic sweat secretion from human eccrine glands.

Effect of PACAP on sweat secretion by immortalized human sweat gland cells

The process of sweating plays an important role in the human body, including thermoregulation and maintenance of the environment and health of the skin. It is known that the conditions of hyperhidrosis and anhidrosis are caused by abnormalities in sweat secretion and can result in severe skin conditions such as pruritus and erythema, which significantly reduce the patient’s quality of life. However, there are many aspects of the signaling mechanisms in the process of sweating that have not been clarified, and no effective therapies or therapeutic agents have yet been discovered. Previously, it was reported that pituitary adenylate cyclase-activating polypeptide (PACAP) promotes sweating, but details of the underlying mechanism has not been clarified. We used immortalized human eccrine gland cells (NCL-SG3 cell) to investigate how sweat secretion is induced by PACAP. Intracellular Ca2+ levels were increased in these cells following their exposure to physiological concentrations of PACAP. Intracellular Ca2+ was not elevated when cells were concomitantly treated with PA-8, a specific PAC1-R antagonist, suggesting that PAC1-R is involved in the elevation of intracellular Ca2+ levels in response to PACAP treatment. Furthermore, immunocytochemistry experiments showed that aquaporin-5 was translocated from the cytoplasm to the cell membrane by PACAP. These results suggest that PACAP acts on eccrine sweat glands to promote sweat secretion by translocation of aquaporin-5 to the cell membrane in response to increased levels of intracellular Ca2+. These findings also provide a solid basis for future research initiatives to develop new therapies to treat sweating disorders.

Culture of the human pilosebaceous unit, hair follicle and sebaceous gland.

Terence Kealey first pioneered the isolation and organ maintenance of human eccrine and sebaceous glands in the early to mid-1980. This led to subsequent methods describing the isolation and culture of human hair follicles, the human pilosebaceous unit as well as the sebaceous duct. The importance of these models in the study of the biology of human skin glands and appendages has been demonstrated in numerous publications and their importance as models for animal replacement, refinement and reduction (3Rs) is increasingly important. In particular, in vitro (ex vivo) hair follicle culture has played a significant part in helping elucidate the role of signalling molecules in regulating hair growth and hair fibre formation and has been especially useful in understanding metabolic aspects of hair growth. However, obtaining sufficient numbers of hair follicles is becoming increasingly difficult as plastic surgery becomes less invasive and smaller skin samples provided. There is therefore an urgent requirement for the next generation of in vitro models using cell lines and tissue engineering, and this has led to the development of immortalised cell lines as well as attempts to model hair follicle embryogenesis in vitro and development of skin on a chip.

Dissociative and Nondissociative Models for Culture of Human Eccrine Glands for Toxicology Testing and Tissue Engineering Applications

Abstract Current in vitro models of human skin lack appendages, which are an integral component of native skin and are necessary structures in reconstructed skin models for applications such as testing of pharmacological agents, basic discovery, and tissue engineering. We describe our development of three complementary in vitro human eccrine gland culture models: (1) nondissociative model of whole eccrine glands attached to epidermis, (2) nondissociative model of whole eccrine glands detached from epidermis, and (3) dissociative model of eccrine gland cells. In each model, eccrine glands were encapsulated and cultured in modifiable hyaluronic acid-based hydrogels. Glands in these cultures stained positive for eccrine gland ductal and secretory coil-specific markers, demonstrating the ability of these models to continue to express appropriate phenotypic markers. The nondissociative models of eccrine gland culture maintain full, intact eccrine gland structures ideal for basic discovery and toxicology testin...

The human eccrine sweat gland: Structure, function and disorders

The ability to thermoregulate is a key component in allowing humans to live and work in a variety of torrid environments. A key thermoregulatory component is the role the skin plays in dissipating heat, through vasodilation of skin blood vessels and its critical role in the secretion of sweat. The role of sweating has for a long time been regarded primarily as the main function of the human eccrine sweat gland, although it has been known for a considerable length of time that sweat, produced in response to heat and exercise, was more than just a salt solution and contained a variety of other substances in addition to electrolytes. Recent studies have shown that there is more to the human eccrine gland, such as manufacturing and releasing compounds that contribute to the defensive barrier of the skin, as well as stem cells present in the gland, having a role to play re-epithelialization of the skin in response to wound healing. Disorders of sweat glands and the resultant conditions, most often relate to de...

Localization of Urea Transporters UT‐A1 and UT‐B in Human Eccrine Clear Cell (LB719)

Urea, a solute classically excreted by the kidney that accumulates in kidney failure, is known to be concentrated in human sweat. Urea is also excreted in the sweat of rat eccrine footpad glands. Therefore, sweat represents an alternative route of excretion for urea. The purpose of this study was to probe for a transporter that might contribute to urea excretion in human skin and rat footpad exocrine glands. Immunohistochemistry was performed on 5 human skin and 5 Sprague‐Dawley rat footpad samples. Human skin was formalin fixed and paraffin embedded for sectioning at 5μm while rat samples were formalin fixed and cryogenically sectioned at 5μm. Polyclonal COOH‐terminal UT‐A and UT‐B antibodies were used to identify the location of UT‐A1 and UT‐B, respectively. Human and rat specimens each contained hair follicles, sebaceous glands, and eccrine glands. Immunoperoxidase staining showed that UT‐B is expressed in the plasma membrane of clear cells in the human eccrine sweat gland. The antibodies did not detect urea transporters in any rat footpad epidermal structures nor the human hair follicles or sebaceous glands. In conclusion, these results suggest the presence of UT‐B in the human eccrine gland. This suggests that UT‐B may contribute to urea secretion in sweat. Future studies are needed to determine whether uremia alters the expression of UT‐B in eccrine sweat glands.舃

Noninvasive Galvanic Skin Sensor for Early Diagnosis of Sudomotor Dysfunction: Application to Diabetes

Sudomotor dysfunction is a major clinical manifestation of diabetic autonomic neuropathy and is an early sign of prediabetes. SUDOSCAN™, a noninvasive and quick method was developed to assess sudomotor function based on measurement of the electrical current response of the skin when different rectangular pulses of low voltage amplitudes are applied on nickel electrodes. Electrochemical skin conductance is then calculated from the resulting voltage and the generated current. This leads to an accurate noninvasive way to predict dysglycemia, including type II diabetes, without fasting requirement due to the sensitivity of Ni electrodes to human eccrine glands sweat.

Development, Structure, and Keratin Expression in C57BL/6J Mouse Eccrine Glands

Eccrine sweat glands in the mouse are found only on the footpads and, when mature, resemble human eccrine glands. Eccrine gland anlagen were first apparent at 16.5 days postconception (DPC) in mouse embryos as small accumulations of cells in the mesenchymal tissue beneath the developing epidermis resembling hair follicle placodes. These cells extended into the dermis where significant cell organization, duct development, and evidence of the acrosyringium were observed in 6- to 7-postpartum day (PPD) mice. Mouse-specific keratin 1 (K1) and 10 (K10) expression was confined to the strata spinosum and granulosum. In 16.5 and 18.5 DPC embryos, K14 and K17 were both expressed in the stratum basale and diffusely in the gland anlagen. K5 expression closely mimicked K17 throughout gland development. K6 expression was not observed in the developing glands of the embryo but was apparent in the luminal cell layer of the duct by 6 to 7 PPD. By 21 PPD, the gland apertures appeared as depressions in the surface surrounded by cornified squames, and the footpad surface lacked the organized ridge and crease system seen in human fingers. These data serve as a valuable reference for investigators who use genetically engineered mice for skin research.

Matrigel-Induced Tubular Morphogenesis of Human Eccrine Sweat Gland Epithelial Cells

Human eccrine sweat glands are tubule-structured glands of the skin that are vital in thermoregulation, secretion, and excretion of water and electrolytes. A study of tubular morphogenesis in vitro would facilitate the development of a tissue engineering model for eccrine sweat glands and other tubule-structured glands. Matrigel, a basement membrane matrix, has been shown to promote differentiation and morphogenesis of many different cell types, including tubular cells. This study investigated the growth, differentiation, and tubular morphogenesis of human eccrine sweat gland epithelial cells cultured in Matrigel. Human eccrine gland epithelial cells were isolated and cultured in vitro. The cell growth in Matrigel was evidenced by the formation of cell clusters, which were observed under an inverted microscope. The internal structure of the cell clusters was further investigated by hematoxylin-eosin (HE) staining and confocal laser scanning microscopy (CLSM) of propidium iodide-stained nuclei. The results demonstrated that although on a plastic surface or in a collagen gel the cells could not form tubular structures, they formed tubular structures when cultured in Matrigel. Consequently, we conclude that Matrigel can promote tubular morphogenesis of human eccrine sweat gland epithelial cells.

Hormone receptor expression in interdigital glands of the Asian elephant (Elephas maximus)

AbstractRecently, our group performed the first histologic, histochemical, and immunohistochemical analysis of eccrine‐type interdigital glands in the Asian elephant (Elephas maximus) (Lamps et al. [2001] Res Vet Sci 71:197–200). Since morphologically similar human eccrine glands express reproductive hormone receptors (including androgen, estrogen, and progesterone receptors), the purpose of the current study was to determine whether interdigital eccrine glands in the Asian elephant contain these same hormone receptors. Necropsy samples of interdigital areas from two adult Asian elephants (one male and one female) were obtained. Immunohistochemical staining was performed for estrogen, progesterone, and androgen receptor proteins. Immunoreactivity to all three receptor proteins was seen in a nuclear distribution in eccrine glands from both samples. This staining pattern is similar to that seen in human eccrine glands and tumors of eccrine derivation, although the significance of the receptor protein expression is unknown. The immunoreactivity of elephant interdigital glandular epithelium with monoclonal antibodies raised to human receptor proteins also suggests a high degree of phylogenetic conservation of these proteins between Asian elephants and humans. Despite detailed morphologic characterization, the function of these glands remains unclear. Further studies are needed to elucidate the function of these glands, the possible relationship between hormone receptor expression and circulating hormone levels, and the potential role of these glands in chemical communication in Asian elephants. Zoo Biol 23:463–469, 2004. © 2004 Wiley‐Liss, Inc.

Cutaneous eccrine glands of the foot pads of the small Madagascan tenrec ( Echinops telfairi, Insectivora, Tenrecidae): skin glands in a primitive mammal.

In order to find correlations between skin gland morphology and specific ethological features, the cutaneous glands of the foot pads of the primitive mammal the Madagascan tenrec, Echinops telfairi, were studied by histological and various histochemical methods as well as by electron microscopy. In the foot pads specific eccrine skin glands occurred consisting of coiled ducts and tubular secretory portions, the lumina of which were considerably wider than in primate sweat glands. The secretory tubules were composed of branched myoepithelial cells and glandular cells. The latter contained abundant mitochondria, large amounts of glycogen particles and few secretory granules as well as individual heterolysosomes and myelin bodies. The lateral cell membrane was marked by extensive interdigitations. The apical membranes of all glandular cells contained proteoglycans with sulfated and carboxylated groups containing N-acetyl-glucosamine, N-acetyl-galactosamine, galactose and mannose. The expression pattern of cytokeratins of the glandular epithelium was variable and showed similarities to that of the human eccrine glands. Tubulin, vinculin and actin were expressed in the glandular epithelium. The secretory cells showed positive reactions with antibodies against antimicrobial peptides and IgA. A positive reaction was observed with antibodies against the androgen receptor. The PCNA and TUNEL reactions indicated that the tubular skin glands of Echinops are made up of a slowly renewing tissue. We conclude that the glands fulfill several functions: production of a fluid-rich secretory product, which may prevent slipping of the foot pads on the substrate during running or climbing, secretion of antimicrobial peptides and proteins, and playing a role in thermoregulation.

Characterization of interdigital glands in the Asian elephant (Elephas maximus)

In the Asian elephant, wetness akin to perspiration is commonly observed on the cuticles and interdigital areas of the feet; this observation has lead to speculation regarding the existence of an interdigital gland. Our goal was to search for interdigital glands and characterise them morphologically, histochemically, and immunohistochemically. Necropsy samples of interdigital areas from two Asian elephants were obtained. Multiple sections were fixed and processed routinely, then stained with hematoxylin/eosin and differential mucin stains. Immunohistochemistry was also performed for cytokeratins 8 and 10. Interdigital glands resembling human eccrine glands were detected deep within the reticular dermis. Histochemical staining indicated neutral mucopolysaccharides and nonsulphated acid mucopolysaccharides in glandular secretions, and the glandular epithelium also showed immunoreactivity to cytokeratins 8 and 10. Both the histochemical and immunohistochemical staining patterns are analogous to human eccrine structures. This study shows with certainty that Asian elephants possess sweat glands as they are defined histologically.

541The α/β ratio of human eccrine glands

541The α/β ratio of human eccrine glands

200 Anti-gastric mucin antibodies react with human eccrine gland

200 Anti-gastric mucin antibodies react with human eccrine gland

Development of a bilayered living skin construct for clinical applications

An in vitro construct of human skin (living skin equivalent, LSE) has been engineered using serially passaged human epidermal keratinocytes and human dermal fibroblasts with a matrix of type I collagen. Cells are obtained from neonatal foreskin. LSE is cast, cultured, and shipped in a single culture insert. The size and shape of the insert determines the size and shape of the LSE. The dermal matrix consists of dermal fibroblasts within a condensed collagen lattice. The overlying epidermis is developed at the air-liquid interface to generate a protective cornified layer. Serum was not necessary for development of the epidermis. LSE for graft (Graftskin) has handling characteristics similar to split-thickness skin allowing it to be meshed, stapled, and sutured. LSE was cryopreserved using 65% glycerol an rapid freezing. Viability and in vivo performance on athymic mice were similar to fresh LSE. Cells derived from human eccrine gland were able to invade and form tubules rudimentary appendages may be possible.

Dispersed Cell Culture of Human Sweat Duct Cells under Serum‐free Conditions

Human eccrine gland duct cells were successfully cultured using a serum-free medium, K-GM medium. Eccrine sweat ducts were isolated from dispase treated skin specimens from palms or soles. After treatment of the isolated ducts with trypsin and EDTA, dispersed cells were cultured in K-GM medium. In primary cultures, small colonies were seen 3 to 4 days after inoculation. Then the cells rapidly proliferated and formed large colonies with a paving stone-like cell arrangement. During the culture, small dome shaped areas were sometimes formed in the centers of colonies. Cultures multiplied for a maximum of 7 passages. The plating efficiencies of the 1st to 6th passage cells were about 20% to 30%. Immunocytochemically, cultured cells were positively stained with anti-carcinoembryonic antigens, K8.37 and K8.13, but not with anti-S100 protein, anti-HLA-DR, 34 beta B4, or PKK3. An electron micrograph of the cultured cells showed a multilayer of flattened cells linked by desmosomes. These results indicate that the cultured cells possessed the staining properties compatible with those of the ductal portion of eccrine sweat glands. No contamination by other mesenchymal cells, such as fibroblasts, was seen during the culture.

Ultrastructural localization of lectin-binding sites in normal human eccrine and apocrine glands

The distribution of carbohydrate residues in eccrine and apocrine glands of normal human skin was studied using a post-embedding technique with Lowicryl K4M. Thin sections were incubated with Ulex europaeus agglutinin I (UEA I), wheat germ agglutinin (WGA), peanut agglutinin (PNA), concanavalin A (Con A), soybean agglutinin (SBA), and dolichos biflorus agglutinin (DBA). All lectins except for PNA showed labeling of the plasma membranes of dark cells, clear cells, and apocrine cells. The granules of the eccrine gland were labeled with all lectins except for DBA. The mitochondrial granules of the apocrine gland were not labeled with any lectin, whereas the lysosomal granules showed a positive reaction with all lectins except for PNA. After incubation with PNA, in eccrine glands the granules were the only structure labeled, whereas in apocrine glands the luminal side of the plasma membrane and cytoplasmic vesicles beneath it were the only structures labeled.

Ultrastructural immunocytochemical studies of blood group substances in human eccrine glands.

We investigated the ultrastructure of blood group antigens A, B, and H in human eccrine glands by means of the immunogold labeling technique. Blood group antigens A, B, and H were found in the Golgi apparatus, secretory granules, and over the apical and basolateral cell membranes of dark cells of eccrine glands depending on the blood group phenotype of the donors. Both A and B antigens were found in the dark cells of AB donors. The labeling pattern of the Golgi stacks seemed to have a polarity whereby the anti-blood group A antibody labeled all the stacks, whereas anti-blood groups B and H bound to the trans side of the Golgi complex. These observations suggest that the blood group substances are secreted into the lumen after being processed through the Golgi apparatus and the immature and mature granules in the dark cells of human eccrine glands.

Fine structure of the human sweat ducts of eccrine and apocrine types.

The sweat ducts of human eccrine and apocrine (ceruminous) glands were observed with the transmission electron microscope. Both the dermal and epidermal segment of the eccrine as well as apocrine ducts consist of two epithelial layers: luminal cells and peripheral cells. Well-developed microvilli, occurrence of cored vesicles, dense granules, multivesicular bodies and phagosomes in the adluminal filamentous zone, and a strong accumulation of mitochondria in the basal part of the duct epithelium at the dermal segment, as well as an accumulation of small clear vesicles beneath the surface of the luminal cells of the epidermal segment are all prominent in the eccrine duct and concomitant with the special function of the human eccrine duct, i.e., absorption of ions to make the sweat hyotonic and an active endocytosis of some material from the sweat. All of the above enumerated characteristics of the eccrine duct are only rarely or never seen in the apocrine duct. On the other hand, lipid droplets appear in the peripheral cells in a certain level of the apocrine duct near its orifice into the hair follicle, suggesting a kind of metaplasia towards the sebaceous gland. Epidermal duct cells of both eccrine and apocrine sweat glands may keratinize. In the eccrine duct the process in the duct cells precedes the surrounding keratinocytes, while in the apocrine duct the relationship is reversed.

Drug Excretion in Human Eccrine Sweat

Six healthy adult male volunteers received single doses of sulfaguanidine (6 g), sulfadiazine (4 g), antipyrine (1 g) and aminopyrine (1 g). These drugs include physical properties ranging as follows: pK 1.4–10.0, excluding drugs largely ionized at physiologic pH; partition coefficient, k: 0.001–0.15; molecular dimensions approximately constant. Sweat (S) and plasma (P) levels of drugs were determined chemically in specimens obtained serially 0–4 hr. after drug administration. For these subjects steady state S/P rations of free drug concentrations were approximately 0.1, 0.1, 1.0 and 2.0 respectively. The findings are consistent with passive diffusion in the dermal excretion of these drugs and show an apparently nonlinear relationship between S/P ratio and partition coefficient. However, the high S/P value for aminopyrine is probably due, not to its higher partition coefficient, but to its extensive ionization in the acidic milieu of sweat. The data are consistent with partitioning of the drugs between plasma of pH 7.4 and a fluid of pH near 5.0. The results emphasize that partition coefficient, in addition to pK, is important in determining the rate of excretion of drugs via the human eccrine gland. Such excretion appears to be maximal with basic drugs having high partition coefficients and pK0 values close to the value of sweat pH so that ionization is maximal in sweat and minimal in plasma. A significant amount of drug can be so delivered to the skin surface and such delivery might be of considerable significance toxicologically and therapeutically.