Sebaceous Duct Research Articles

Squamous Eddies Are Spirals of Sebaceous Ducts

Squamous Eddies Are Spirals of Sebaceous Ducts

Eruptive Vellus Hair Cysts

The eruptive vellus hair cyst is an uncommon, yet distinct, clinical and pathological entity that may be acquired in a sporadic or hereditary form. This descriptive term gives no indication of the type of epithelium lining this cyst. A case report of eruptive vellus hair cyst is reported herein in which the epithelial lining differentiated toward the sebaceous duct. We propose that eruptive vellus hair cysts should be more accurately diagnosed by characterizing the type of epithelial lining.

Immunohistochemical markers of human sebaceous gland differentiation.

Cryostat sections of human skin were stained with monoclonal antibodies to involucrin, a range of cytokeratins, epithelial membrane antigen (EMA), and an ovarian cystadenocarcinoma antibody (OM1) to identify combinations of antibodies that could be used to discriminate between basal and differentiated sebocytes and other cell types present in the pilosebaceous unit. Both the EMA and OM1 monoclonal antibodies specifically recognized differentiated sebocytes. No staining of basal sebocytes or other epidermal cell types was seen. Differentiated (but not basal) sebocytes were also stained by a cytokeratin 10 antibody (LH2). Conversely, the basal sebocytes were recognized by an antibody specific to basal keratinocytes (LH6). Cells of the sebaceous duct stained with both LH2 and LH6 and also with the anti-involucrin monoclonal antibody. Cytokeratin 4 has been detected in sebaceous glands by protein analysis but has not previously been detectable immunohistochemically. We show by immunofluorescence after limited proteolysis that cytokeratin 4 epitopes are distributed in all sebaceous gland cells, including the duct cells.

Monoclonal Antibody Labeling for Cytokeratins and Filaggrin in the Human Pilosebaceous Unit of Normal, Seborrhoeic and Acne Skin

The distribution of cytokeratins and filaggrin in human pilosebaceous unit was investigated in specimens obtained from normal (n = 15), seborrhoeic (n = 6), and acne skin (n = 6), using the monoclonal antibodies CK8.12, CK8.13, CK4.62, CK8.60, KL1, PKK2, RPN 1160, and an antibody for filaggrin. The type and amount of cytokeratin content was correlated with the stage of cell differentiation in these three skin types. In all specimens studied the sebocytes. The sebaceous duct cells, and the infundibular cells contained cytokeratins, no clear differences were found between normal, seborrhoeic, and acne skin. During sebocytic maturation the amount and type of cytokeratin content changed gradually and the labeling pattern was partly different compared to the interfollicular epidermal pattern. In the sebaceous duct and the infundibulum, the labeling pattern using KL1, CK8.12, and CK8.13 was similar to that seen in interfollicular epidermis, whereas labeling with CK8.60 and PKK2 was different. These findings indicate that sebaceous duct and infundibular cells express transitional patterns of differentiation between epidermal keratinocytes and sebocytes. Filaggrin was expressed only in some sebaceous duct cells and in infundibular cells. In seborrhoeic and in acne skin, however, the reactivity of antibody to filaggrin was more intense and was already observed in the lower parts of the sebaceous duct and the infundibulum. Although no filaggrin was found in the intermediate cells of the sebaceous duct and the infundibulum in normal skin, these cell types clearly contained filaggrin in seborrhoeic and acne skin.

Transglutaminase Activity in Human and Rabbit Ear Comedogenesis: A Histochemical Study

Using monodansylcadaverine as a fluorescent, lysine-substrate analogue, alterations in the histochemical profile of transglutaminase activity during human and coal tar-induced rabbit ear comedogenesis were examined. When compared to the normal pilosebaceous follicles of both species, a marked increase in enzyme-specific fluorescence in the hyperplastic epidermal lining and in the epithelium of the sebaceous duct was observed in human and rabbit early lesions. In mature human open and closed comedones, an intact band of transglutaminase activity corresponding to the differentiating epidermal cell layers was seen to surround the lesion. In mature rabbit comedones this band of activity was most striking. In most lesions, transglutaminase activity was closely apposed to the plasma membrane of the differentiating keratinocytes, the site of cornified envelope formation. In normal human and rabbit interfollicular epidermis the cornified layer immediately above the fluorescent granular layer was histochemically inactive, while the surface stratum corneum showed an increase in activity. A similar phenomenon was observed in many comedones. This pattern of activity may relate to the process of desquamation. Finally, the changes in transglutaminase activity observed during comedogenesis suggest the possibility that inhibitors of transglutaminase could be useful in acne therapy.

Distribution of major histocompatibility antigens in normal skin.

The distribution of major histocompatibility antigens HLA-A,B,C (HLA), beta 2-microglobulin (beta 2m), and Ia-like antigens (HLA-DR; Ia) in normal skin was studied in frozen tissue sections by a four-step immunoperoxidase method and an avidin-biotin method employing monoclonal antibodies. HLA and beta 2m were present on the basal and spinous keratinocytes of the epidermis, on the outer root sheath epithelium in the infundibulum of the hair follicle, and on the excretory sebaceous duct epithelium. Ia-positive dendritic cells were found in the epidermis and hair follicles, but they were more frequent in the infundibulum and isthmus of the hair follicle than in its inferior portion or in the epidermis. In the straight eccrine duct, HLA and beta 2m-positivity was most striking in its lower portion. In the superficial duct, there was a less intense staining using the four-step procedure, but when an avidin-biotin method was used, the difference was less apparent. In contrast, the acrosyringial epithelium was markedly Ia-positive with decreasing intensity of staining as the duct penetrated the dermis. No HLA or Ia antigens were identified in eccrine glands and apocrine glands. Eccrine glands were slightly beta 2m-positive. HLA and beta 2m were uniformly present in non-dilated and dilated intradermal apocrine ducts.

Morphological and histological features of the integument of the New Zealand sea lionPhocarctos hookeri

Abstract Morphological and histological features of the integument of 2 Hooker’s sea lions, obtained dead in February, were examined. In a 3- week-old pup there were 7 rows of mystacial vibrissae, comprising 40 on the left side of the muzzle and 38 on the right. In the skin of the torso the guard hairs were in the quiescent phase of their growth cycle. In a 2½-year-old specimen a moult was imminent; guard hairs in quiescent follicles were about to be displaced by fibres in developing follicles. Histological features of the older sea lion, which may have been age-related, were coarser collagen bundles in the reticular layer of the dermis and a greater number of secondary follicles. In guard hair follicles of both animals the sweat gland duct opened above the sebaceous gland duct.

Steatocystoma multiplex: anatomic reevaluation, electron microscopy, and autoradiography.

Histologic and electron-microscopic features of steatocystoma multiplex were investigated. Specimens from 25 patients (8 females, 17 males) were serially cut and three-dimensional drawings constructed. Steatocystoma multiplex is a nevoid sebaceous duct and sebaceous gland tumor, originating from sebaceous follicles, but is not a dermoid tumor. One pilary unit continuously produces vellus hairs, which are trapped in the cystic cavity or in the pilary canal (trichostasis). Steatocystoma multiplex is connected to the epidermis by a straight or meandering epithelial cord, the remnant of the follicular infundibulum. This infundibulum is a more or less solid strand, often containing sebocytes or sebaceous lobulelike structures. A lumen, partly present in a few areas of the cord, is filled with cellular debris of keratinocytes, corneocytes, sebocytes, or trapped hairs. Steatocystoma multiplex has electron-microscopical features similar to the sebaceous duct and sebaceous glands of sebaceous follicles. The 3H-thymidine labeling index of the cyst wall with or without sebaceous acini is lower than in sebaceous follicles. Steatocystoma multiplex suppurativum, characterized by spontaneous rupture of the cyst, inflammation and scarring, mimics acne conglobata with hidradenitis-suppurativa-like lesions as seen in the acne triade or tetrade.

On the mechanism of sebaceous secretion.

Following the studies of Kligman, most investigators now believe that sebaceous glands function continuously in excreting sebum to the skin surface [7, 8]. Populations of differentiating cells are maintained by mitotic activity both in the peripheral cells of the sebaceous lobules and in aggregations of undifferentiated cells which extend through the body of the lobules. Once formed, and as long as maintained by circulating hormones, each lobule continues to produce a stream of differentiating cells which accumulate sebum as they move towards the sebaceous duct and finally disrupt to release their contents into the pilosebaceous canal. After intradermal injections of 3H-thymidine to label germinative cells during DNA replication, up to 28 days elapse before all labeled cells disappear from the glands. When differentiating cells are labeled with 3H-amino acids, much of the label is lost in 7 days. Likewise, when lipids are labeled with 14C-acetate, the average excretion time for the labeled sebum is 8 days. To this time may be added the renewal time of undifferentiated cells to give an average sebaceous cell transition time of 14 days [15]. From knowledge of the time between synthesis and excretion of sebum, sebum production rates were calculated from the sebum content of punch biopsies. The transit time of sebum in the follicular canals was estimated to be 14 h. Production rates determined in this way agree with those measured by long-term absorption of sebum at the skin surface.

An ultrastructural study of steatocystoma multiplex and the normal pilosebaceous apparatus.

ABSTRACTIn order to clarify the site(s) from which steatocystoma multiplex (SCM) originates, five cases of SCM and the normal pilosebaceous apparatus were comparatively examined by electron microscopy. The cyst‐wall of SCM, consisting either of flattened or of undulating horny layer, contained a small number of tonofilaments, desmosomes, and tiny spherical keratohyalin granules. There were variable numbers of lamellar granules which were also frequently observed in the intercellular spaces of the horny layer. Three of the SCM cases included sebaceous cells. The contents of the cysts were mostly amorphous and short‐fibrillar, but sometimes keratinized cells and remnants of lamellar granules were observed. These findings were analogous to those of the normal pilosebaceous apparatus from the level of the lower part of the infundibulum to the outer root sheath Via the sebaceous duct, and were specifically more analogous to those of the sebaceous duct.

The process of replacement of vellus hairs by coarse hairs.

The authors report a detailed histologic study of the process of replacement of solitary vellus hairs by solitary coarse hairs in the axilla. The replacement process is revealed to be quite different from the ordinary hair cycle. In puberty, hormonal activity causes the vellus hair follicle to become multilobular. The vellus hair expires, and formation of a new bud and a new (coarse) hair begins to develop from the upper isthmal portion of the follicle just below the sebaceous duct. The new hair pegs downward, until the formation of a new hair bulb (matrix) is completed, and then grows upward as a coarse terminal hair.

Acne and Antibiotics

Acne vulgaris is a disorder of the skin which begins with the accumulation of sebum in the sebaceous duct. The pressure built up by the accumulated sebum can rupture the duct. Diffusion of the sebum, particularly of its fatty acids, into the skin brings about an inflammatory reaction often accompanied by an infection. Besides causing infection, the bacteria produce lipases that stimulate the inflammatory processes by hydrolyzing the sebum into fatty acids. These effects can be attributed to both Corynebacterium acnes and Staphylococcus epidermidis. The way in which both oral and topical antibiotics can be used in, the treatment of acne is reviewed. The possibility for combined local treatment with an antibiotic and an antiandrogen is discussed.

Histologic Study of the Regeneration of Axillary Hair after Removal with Subcutaneous Tissue Shaver

It was observed that after subcutaneous tissue shaving for the radical therapy of hircismus and hyperhidrosis axillary hair often regrew. Histologic study of this phenomenon showed that hair bulb and most of the follicle up to a level near the sebaceous duct opening had been removed. Hair regrows from remnant outer root sheath, but only when sebaceous glands are preserved, that is when the upper portion of the follicular isthmus is intact. One or several solid epithelial pegs grow downward from the cut end of the trichilemma, and inner root sheath and new young hair are formed in its center. In hair peg stage, the lower tip of the hair follicle descends while new hair is growing in its center through the mitotic activity is growing in its center through the mitotic activity of hair germ cells and is prevented from pushing toward the skin surface by interlocking fusion between hair cuticula and sheath cuticula. Eventually, the epithelial cells wrap around a mass of mesenchymal cells and form a new bulb from which the terminal hair grows upward. The new matrix acquires a new complement of functioning melanocytes.

Regeneration of axillary hair and related phenomena after removal of deep dermal and subcutaneous tissue by a special "shaving" technique.

A subcutaneous tissue "shaver" was used in the treatment of axillary bromhidrosis. Regeneration of axillary hair was observed postoperatively even if subcutaneous tissue and dermis were removed almost up to the level of sebaceous ducts. Hair regenerated more often in male patients whose sebaceous glands and follicular isthmus were designedly left intact than in female patients whose sebaceous glands were designedly removed completely. Some function of apocrine and eccrine glands tends to return over a two-year period.

A quantitative study of membrane coating granules in follicles undergoing experimental comedo formation.

Membrane coating granules (MCGs) may be required for normal keratinization. Comedone formation is associated with abnormal keratinization, and so the MCGs in sebacaous follicles were counted during experimental comedogenesis in the rabbit. During induced comedo formation with 50% oleic acid in paraffin oil, the numbers of MCGs decreased significantly; first, at the epidermis and mouth of the follicle and then later, at the follicular canal and common sebaceous duct. The maximum decrease of about 40% was reached by the 6th day in these regions. Throughout the treatment, the MCG count in the individual sebaceous ducts remained fairly constant.

Topical Androgen Treatment for ACNE a Review

Acne results from the increased production of sebum and the accumulation of sebum in the sebaceous duct. Androgens have a direct influence on this condition as they stimulate both the formation of sebum and the hyperkeratinisation of the upper part of the duct which leads eventually to its obstruction. Clinical tests have demonstrated that most acne patients do not have an increased level of androgen in the blood. They do, however, show an increased conversion of testosterone to 5-alpha-dihy-drotestosterone (5-alpha-DHT) in the skin. This latter hormone is responsible for the stimulation of the sebaceous gland. The enzymic conversion of testosterone to 5-alpha-DHT can be inhibited by progesterone. Progesterone, when applied topically in an alcohol/water solution, is 80 percent metabolized in the skin and is not converted into androgens in the body. It may therefore be expected that the topical application of progesterone will not give rise to side effects in either men or women. Preliminary trials are in agreement with this expectation. Extensive clinical investigations of an alcohol/ water solution of progesterone are therefore recommended, as this may be the first clinically useful, locally active, antiandrogen to be effective in the treatment of acne.

On the propionibacteria in the pilosebaceous ducts of uninvolved skin of acne patients.

In 24 persons with a severe inflammatory acne and 48 control subjects, bacteria were sampled from the sebaceous gland exretory ducts with the glass sampling head method according to Holland et al. After anaerobic culture bacterial counts were performed. The total numbers of P. acnes and the frequency of detection of P. granulosum were determined. The bacterial counts of P. acnes were almost idendical in the two collectives. P. granulosum was detected at a significantly higher frequence in the acne patients than in the control subjects. It can be assumed on the basis of the results that an increase in the bacterial counts of P. acnes is not to be regarded as a pathogenetic factor in the inflammatory acne of older patients. On the other hand, they suggest that P. granulosum may have an appreciable role in acne.

Anatomical, histological and histochemical observations and changes in the poll glands of the camel (<i>Camelus dromedarius</i>)

This study deals with the anatomical, histological and histochemical observations and the changes in the poll glands due to age, seasonal variations and castration. The male camels had two poll glands, one on either side of the mid-line of the poll region. The glands were present in the male camels at birth, while no visible glands were observed in the she-camels at any age. The weight and dimensions of the glands increased with age in the uncastrated camels, but the glands regressed after castration. The active glands were compound tubulo-alveolar glands. The tubules and alveoli were lined by simple squamous to high cuboidal epithelium depending on the secretory stages. The mild PAS-reactive apical blebs of the secretory cells were also positive for acid mucopolysaccharides and alkaline phosphatase. The myoepithelial cells around the alveoli and small ducts were PAS-negative. The intralobular ducts were lined by simple cuboidal epithelium. The stratified cuboidal epithelium lining the initial portion of the excretory duct abruptly changed into the stratified squamous epithelium which continued with the cutaneous epithelium of the skin. The ducts opened into the neck of the hair follicles above the level of the sebaceous ducts. The glands appeared to be modified apocrine sweat glands in the histological appearance. The interglandular connective tissue was reduced to thin strands during the winter months while, comparatively, in the summer months, the connective tissue increased. During the winter months of December to March the pungent coffee-coloured secretion from the glands was most profusing in those camels who were apparently in rut. The tubules and alveoli in such glands were lined by high cuboidal cells with apical blebs. During the summer months, the secretion was scanty except in severe exercises, and the glandular epithelium varied from simple squamous to low cuboidal.

HAMSTER EAR MODEL FOR SEBACEOUS GLANDS

The ventral side of the earlobes of Syrian hamsters richly endowed with sebaceous glands. These glands are large and are similar to human sebaceous follicles since they have an infundibulum, a sebaceous duct, multiple lobules, and a pilary unit which enters from below into the gland. In this study we have measured gland size by planimetry,and cellular activity by autoradiography using tritiated thymidine and tritated histidine. Males have much larger glands in sagittal sections than do females(0.1750 mm2 vs 0.0727 mm2, p less than 0.001) and a higher labeling index (19.85% vs 14.3%, p less than 0.01). Injection of testosterone propionate increases the gland size in female hamsters to 0.2362 mm2 (p less than 0.001). The labeling index also increases. The turnover of the total gland population is 12 to 14 days. Androgen sensitivity, gland size, and turnover time make the sebaceous glands on the ventral surface of the hamster earlobe a suitable model for study.

Hydrolytic enzymes in the sebaceous glands of the domestic cat.

The distribution and activities of some hydrolytic enzymes in various portions of the sebaceous glands of the domestic cat have been studeid. The results point to the outstanding importance of none-specific esterases and lipases for sebum production, which generally appears to be abundant in thickly-haired mammals. The activities of the lysosomal enzymes demonstrated were connected with autolytic processes during sebaceous gland cell differentiation. There was a strong aryl-sulphatase reaction in the sebum of the sebaceous gland excretory ducts.