Early histological and ultrastructural changes in expanded murine scalp.

Tissue expansion has been widely used for plastic, reconstructive, and esthetic surgeries. A mouse scalp expansion model can effectively mimic the characteristics of human skin expansion. However, a detailed study of the histological features and ultrastructural characteristics of expanded scalp is lacking, especially early ultrastructural changes. Here, a mouse scalp expansion model was established and the expanded scalp samples were obtained on day 2 (group I) and 4 (group II) post final injection. Histological analysis revealed epidermal thickening, dermal thinning, subcutaneous fat thinning, and capsule formation in the expanded samples. Ultrastructural evaluation showed the presence of keratinocytes with numerous tonofibrils and damaged mitochondria, and several ruptured collagen fibers and increased number of active fibroblasts and myofibroblasts were observed in the dermis and capsules. Adipocyte dedifferentiation was detected in the expanded samples of both groups, but formation of autophagosomes was only detected in the dermal fibroblasts of group I. Thus, early changes in expanded tissue should be carefully monitored, as it may help avoid dermal thinning and promote expanded tissue regeneration.

The walking dead: sequential nuclear and organelle destruction during hair development.

BACKGROUND: Transition of hair shaft keratinocytes from actively respiring, nucleated cells to structural cells devoid of nucleus and cytoplasm is key to hair production. This form of cell 'death', or cornification, requires cellular organelle removal to allow the cytoplasm to become packed with keratin filament bundles that further require cross-linking to create a strong hair fibre. Although these processes are well described in epidermal keratinocytes, there is a lack of understanding of such mechanisms, specifically in the hair follicle. OBJECTIVES: To gain insights into cornification mechanisms within the hair follicle and thus improve our understanding of normal hair physiology. METHODS: Scalp biopsies and hair-pluck samples were obtained from healthy human donors and analysed microscopically after immunohistochemical staining. RESULTS: A focal point of respiratory activity was evident in keratogenous zone cells within the hair shaft, which also exhibited nuclear damage. Nuclear degradation occurred via both caspase-dependent and caspase-independent pathways. Conversely, mitophagy was driven by Bnip3L and restricted to the boundary of the keratogenous zone at Adamson's Fringe. CONCLUSIONS: We propose a model of stepwise living-dead transition within the first 1 mm of hair formation, whereby fully functional, nucleated cells first consolidate required functions by degrading nuclear DNA, yet continue to respire and provide the source of reactive oxygen species required for keratin cross-linking. Finally, as the cells become packed with keratin bundles, Bnip3L expression triggers mitophagy to rid the cells of the last remaining 'living' characteristic, thus completing the march from 'living' to 'dead' within the hair follicle.

Dermal Titanium Dioxide Deposition Associated With Intralesional Triamcinolone Injection.

Cutaneous discoloration secondary to dermal deposition of titanium dioxide (TiO2) particles is recognized but seldom reported in the literature. In this report, the authors describe the case of a 61-year-old gentleman, with a long history of alopecia areata, who presented with numerous, discrete dark blue macules on the scalp. Scanning electron microscopy with energy dispersive x-ray spectroscopy analysis ultimately identified the macules as deposits of TiO2. The patient had a history of intralesional triamcinolone injections for management of alopecia areata. A sample of generic 0.1% triamcinolone acetonide paste was analyzed and found to contain many TiO2 particles analogous to those seen in the patient's biopsy sample. To the authors' knowledge, this is the first reported case of TiO2 deposition in the dermis likely resulting from topical combined with intralesional triamcinolone injection.

Alterations in Hair Follicle Morphology and Hair Shaft Production After Follicular Unit Transplantation.

Follicular unit transplantation is the most commonly performed technique in modern restorative hair transplantation surgery. It relies on the acquisition of intact follicular units from microdissected scalp skin strips and their subsequent transplantation into the recipient regions affected by alopecia. Ideally, the translocation of follicular units from the balding-resistant areas of the scalp (usually the occipital region) to the recipient site should not result in any morphological change in the grafts. Nevertheless, the insults associated with surgical intervention present grafted follicles to mechanical and chemical cues differently from those of the physiological steady-state conditions in undamaged skin. This disruption of the normal follicular microenvironment might alter important aspects of hair biology in grafts, for example, hair cycle and pigmentation, and, in turn, could lead to differences in hair appearance, eventually culminating in a diminished esthetical outcome of the surgery. In this study, the authors analyzed native and grafted scalp hair follicles (HFs) from 2 patients who had undergone follicular unit transplantation surgeries formerly. Scanning electron microscopy and light microscopy-based histomorphometry revealed a marked enlargement of follicular structures in the grafts with a concomitant increase in hair shaft diameter. Immunohistological staining confirmed a thickening of the dermal sheath in transplanted HFs that also harbored a denser vascular network. Taken together, these results show that the grafted HFs analyzed were subjected to marked morphological changes during their residence in the recipient site and that this phenomenon is associated with a modulation of follicular vascularization.

Evaluation of ATP content in hair bulbs in human scalp.

The content of ATP in scalp hair bulbs in humans was measured in the hair roots from 15 healthy volunteers. Light and electron microscopy confirmed the presence of outer and an inner root sheaths in the root of pulled out anagen hair. Incubation of samples in buffer solution led to extraction of ATP, which was measured by the chemiluminescent method. Mechanic disintegration of hair bulbs and their freezing-defrosting did not increase ATP output. The results of microscopy indicated that ATP extraction procedure was associated with separation of the outer radical sheath from the inner one without impairing the structure of the inner sheath. The mean content of ATP was 12 ± 2 pmol per bulb. The use of pulled out hair bulbs for ATP measurements simplified the procedure as involved no surgical removal of follicles.

Trichoscopy: an update.

Hair and scalp disorders represent a substantial complaint in most dermatologists' daily practice. Trichoscopy is a simple and easy-to-perform technique that has been utilized for diagnosis and management of these patients. The interest for this technique had increased in the last years, and knowledge had expanded. This article reviews the most important dermoscopic patterns in normal Caucasian and African scalp, as well as in the most common trichological conditions.

[Age peculiarities of the sebaceous glands in the temporal area of the scalp skin in men].

The changes of the sebaceous gland number, size and sebocyte proliferative activity were studied in the temporal area of the scalp skin in the male individuals aged 10 to 70 years (n=77, autopsy material). The minimal number of the sebaceous glands was observed in children. This index rapidly increased thereafter, reaching a peak at 20 years, then gradually decreased. These parameters correlated with the sebaceous gland size, sebocyte proliferative activity and total blood testosterone level. In older men the size of the sebaceous glands was increased.

Acquired nonscarring diffuse hair loss in a 3-year-old girl.

A 3-year-old girl showed fine, sparse, and brittle scalp hair without signs of cicatricial cutaneous alterations. Dermoscopy as well as scanning electron microscopy revealed elliptical nodes as well as constricted regions along the hair shaft.

[Age-related changes of the epidermis of men's scalp].

Histological, morphometric and immunocytochemical methods were used to study the autopsy samples of the interfollicular epidermis in the temporal region of scalp of male individuals aged from 7 months to 75 years. Monoclonal antibodies against Ki-67, involucrin and p53 were applied to evaluate the proliferative pool in the epidermis, the thickness of the layer of the cells which started the terminal differentiation, and the fraction of the apoptotic cells. Epidermis in children was thin; it had a low content of Ki-67- and p53-positive cells and small thickness of involucrin-positive cell layer. The highest proliferative activity and maximal thickness of the epidermis were detected at the age of 19-21 years. Thereafter the epidermis thinning was observed, together with the progressive decrease of keratinocyte proliferative activity and an increase of the fraction of p53-positive cells. Absolute thickness of the involucrin-positive cellular layer remained practically constant at different ages, while its proportion in the total epidermal thickness uncreased.

Evaluation of Hair Density and Hair Diameter in the Adult Thai Population Using Quantitative Trichoscopic Analysis.

The data of hair density and hair diameter in the Asian population, especially in Thais, are limited. We aimed to evaluate hair density and hair diameter of members of the Thai population at different scalp sites and to determine the effect of sex and aging as well as to compare the results with those in groups of other ethnicities. Healthy Thais whose hair examination findings were normal were evaluated. Two hundred and thirty-nine subjects participated in this study, of whom 79 were male and 160 were female. Hair density and hair diameter were analyzed at four different scalp sites using quantitative trichoscopic analysis. The highest hair density in Thais was observed in the vertex area. Hair densities at four different scalp sites were significantly different from one another; only hair density at the vertex site showed no significant difference from that in the occipital area. In contrast, hair diameter did not show any statistically significant differences for the different sites. We observed decreased mean hair density with increasing age and found statistically significant differences between participants in their 20s and those in their 60s, while hair diameter remained consistent. Comparing our results with a previous study in other ethnicities, the hair densities in Asians are generally lower. In conclusion, hair density in the Thai population varies at different scalp sites. Aging is a factor in declining hair density. Asians have a lower hair density compared to Caucasian and African populations.

Ultrastructural and immunohistochemical characteristics of telocytes in human scalp tissue.

This study was designed to characterize the location, morphology and ultrastructure of telocytes (TCs) in human scalp tissue. After obtaining approval for this study and informed consent from the patient, a scalp specimen was obtained. The distribution and morphology of TCs in human scalp tissue was assessed by immunohistochemical staining of CD34 and CD117/c-KIT, and the ultrastructure of TCs was investigated using transmission electron microscopy (TEM). Immunohistochemical staining of CD34 revealed that TCs were located in the connective tissue of human scalp, and were concentrated around hair follicles (HFs), blood vessels, sweat glands, sebaceous glands and adipose lobules. Immunohistochemical staining of CD117 revealed that TCs were mainly located in the dermis of human scalp, surrounding the HFs and sweat glands. Under TEM, TCs were seen and confirmed by their special morphological features. These cells were spindle-shaped, had small cell bodies and long thin processes, and surrounded stem cell clusters in the bulge region of HFs. These results demonstrate that TCs in human scalp were positive for CD34 and CD117, and their strategic positioning surrounding stem cells suggests their possible involvement in local regeneration, remodeling and homeostasis of the skin.

AFM analysis of collagen fibrils in expanded scalp tissue after anisotropic tissue expansion.

Successful use of tissue expanders depends on the quality of expanded tissue. This study evaluates the impact of anisotropic self-inflating tissue expander (SITE) on the biomechanics of skin. Two different SITE were implanted subcutaneously on sheep scalps; SITE that requires 30days for maximum expansion (Group A; n=5), and SITE that requires 21days for maximum expansion (Group B; n=5). Control animals (n=5) were maintained without SITE implantation. Young's Modulus, D-periodicity, overlap and gap region length, diameter, and height difference between overlap and gap regions on collagen fibrils were analyzed using atomic force microscopy. Histology showed no significant differences in dermal thickness between control and expanded skin of groups A and B. Furthermore, most parameters of expanded skin were similar to controls (p>0.05). However, the height difference between overlap and gap regions was significantly smaller in group B compared to both control and group A (p<0.01). Strong correlation was observed between Young's Modulus of overlap and gap regions of the control and group A, but not group B. Results suggest that a relatively slower SITE can be useful in reconstructive surgery to maintain the biomechanical properties of expanded skin.

Intranuclear rodlets and associated true intranuclear bodies in normal cultured human dermal papilla cells.

The dermal papilla is believed to exert controlling influences on hair growth. This report documents, for the first time, the occurrence of intranuclear rodlets in normal cultured human dermal papilla cells. Intranuclear rodlets have been observed predominantly in normal neurons, neural neoplasms, and paraneuromas. Whereas intranuclear rodlets and complex intranuclear bodies have not been identified in dermal papilla cells in vivo, they were observed, by light microscopy and transmission electron microscopy, in primary and subsequent passaged cultures in all 10 individuals examined. Intranuclear rodlets and bodies were not found, however, in parallel cultures of scalp dermal fibroblasts from the same individuals. Rodlet ultrastructure in cultured dermal papilla cells exhibited many features in common with previous reports on rodlets in neuronal and paraneuronal cells. Features that differentiated the rodlets in this study, however, included: doublet/triplet rodlets in the same nucleus; rodlets or crystalline filament bundles within complex nuclear inclusions; close relationship with the nuclear membrane, and their frequent intimate association with intranuclear bodies; and nucleoli and fine chromatin-distinct fibrillar material. Although the function of these true intranuclear inclusions in dermal papilla cells is unknown, it is noteworthy that they were present in these highly metabolically active fibroblasts while absent in comparatively less active dermal fibroblasts, and may indeed be a marker for this fibroblast cell type.

Immunocytochemical localization of androgen receptors in the scalp of the stumptail macaque monkey, a model of androgenetic alopecia.

The purpose of this study was to identify the distribution of androgen receptors in the bald and hairy scalp of adult male and female stumptail macaque monkeys by light microscopic biotin-avidin immunocytochemistry with a highly purified rat monoclonal antibody against the cloned human androgen receptor. Consistent, intense nuclear and minimal cytoplasmic immunostaining was observed in several distinct cell populations of the pilosebaceous unit including the dermal papilla, hair epithelium, outer root sheath, dermal sheath, and sebaceous gland. A similar distribution of androgen receptors was found in miniaturized and terminal anagen and telogen follicles of the bald and hairy scalp, respectively. Binding of androgen receptor antibody was also detected in dermal fibroblasts, basal and intermediate layers of the interfollicular epidermis, and duct and glandular cells of eccrine sweat glands. This investigation demonstrates the presence of androgen receptors in the pilosebaceous unit of the scalp of the stumptail macaque and also shows that their distribution is comparable to that previously reported for humans.

Fungus invasion into human hair tissue in black dot ringworm: light and electron microscopic study.

In order to investigate the morphology of fungi invading into the human hair tissue, three cases of black dot ringworm caused by Trichophyton violaceum and Trichophyton glabrum were studied by light and electron microscopy. Fungal elements were mainly present in the hair cortex and showed a constant morphologic change during the differentiation of hair layers. The fungal elements, located deep in the keratogenous zone of the cortex, showed less electron dense non-septate hyphae. Distally, the hyphae showed septation and contained several scattered dense bodies in the cytoplasm. At the level where the Huxley's layer was keratinized, the fungal elements were transformed into arthrospores, which occupied the large volume of the cortex; each spore was surrounded by a fiber- and melanosome-free, electron lucent halo. Fungal elements occasionally invaded the keratinized hair cuticle and keratinized inner root sheath in a few hair follicles. Fungi do not invade the hair germinative cells. There seems to be a distinct relationship between the morphology of the invading fungi and the cortical cell differentiation in black dot ringworm; a balance between the fungus proliferation and the cortical cell development may be present.

Distribution of proteoglycans during the hair growth cycle in human skin.

The involvement of proteoglycans in hair growth has been recognized through the observation of increased hair growth in diseases such as the mucopolysaccharidoses and pre-tibial myxedema, which involve an increase in skin proteoglycan content. In an attempt to understand this, we have examined the distribution of chondroitin 6 sulphate (C6S), unsulphated chondroitin (COS), dermatan sulphate (DS), and heparan sulphate proteoglycans (HSPG) in frozen tissue sections of normal scalp by immunostaining. Results show that during anagen, the thick connective tissue sheath around the follicle strains strongly for C6S, COS, and DS. COS is uniquely associated with this region and is not found beneath the epidermis or infundibular epithelium. HSPG is, however, localized in the basement membrane zone adjacent to the outer root sheath. In addition, all of these proteoglycans are localized in the dermal papilla. In mid-catagen, we observed significant loss of C6S and COS staining from both the dermal papilla and the connective tissue sheath, but no decrease in staining for HSPG. In late catagen, very little staining of C6S and COS was observed. In early anagen, we observed that C6S was again present in the connective tissue sheath and dermal papilla; however, COS staining appeared to be weaker and less closely associated with the follicle. HSPG staining was observed in early anagen in a pattern very similar to that found for other basement membrane components. Results for DS were not obtained for catagen or early anagen. These results provide further evidence that hair growth is associated with the presence of chondroitin proteoglycans in the follicle environment and that the cessation of growth is associated with their removal. Further studies are underway to characterize the relationship between hair growth and proteoglycans.

Immunohistochemical and electron microscopic characterization of the cellular infiltrate in alopecia (areata, totalis, and universalis).

The inflammatory cell infiltrates in scalp skin of 35 patients, 20 with alopecia areata (AA), 7 with totalis, and 8 with universalis were characterized with the ANAE (alpha-naphthylacetate esterase) marker, monoclonal antibodies, and electron microscopy. As demonstrated by the ANAE staining, no clear difference in the main lymphocyte subclasses (T and B cells) or macrophages was seen between the different types of alopecia or as compared to control patients' scalp skin. However, T lymphocytes and macrophages were seen most frequently and in greater numbers perivascularly and infiltrating the hair bulb in those cases of AA where active hair loss took place. Using monoclonal OKT (OKT-3, -4, and -8) antibodies and the avidin-biotin immunoperoxidase method on frozen sections, a concentration of OKT-8 reactive cells (suppressor/cytotoxic T cells) was seen peribulbarly and invading the hair infundibulum. The cells affecting the hair infundibulum were further studied by electron microscopy. They could be classified into three main types: small lymphocytes (60%), macrophages (30%) and cells closely resembling large granular lymphocytes (LGL) (10%). LGL have previously been considered to be human natural killer (HNK) cells. Thus the hair follicle seems to be the target for the cellular immune response in alopecia. Whether HNK cells participate in the destruction of hair bulbs remains to be investigated.

Hamartoma of the scalp with ectopic meningothelial elements. A distinctive benign soft tissue lesion that may simulate angiosarcoma.

Five cases of a distinctive benign soft tissue lesion of the scalp in patients ranging from 4 months to 40 years of age are described. Clinically, the lesions appeared as solitary, subcutaneous nodules suggestive of a cystic vascular malformation or other benign condition. Histologically, however, the lesions were characterized by a monotonous, pseudoinfiltrative proliferation of cuboidal epithelioid cells arranged in clusters within the dermis and subcutaneous tissue in intimate association with vessels, adipose tissue, and other connective tissue elements. A prominent feature in all cases was the presence of areas simulating freely anastomosing vascular channels lined by round to spindle-shaped, slightly hyperchromatic epithelioid cells reminiscent of angiosarcoma. Immunohistochemically, these cells were negative for factor VIII-related antigen and Ulex europaeus lectin but were strongly positive with vimentin and epithelial membrane antigen antibodies, this latter being in keeping with the immunohistochemical profile of meningothelial cells. The meningothelial nature of these cells was supported by the electron microscopic demonstration in one case of cells with complex, interdigitating cytoplasmic processes that were joined by scattered cell junctions and contained abundant intracytoplasmic intermediate filaments. The intimate admixture of meningothelial elements with haphazardly arranged connective tissue elements sets these lesions apart from cutaneous meningiomas and warrants their designation as hamartomas with an ectopic meningothelial component.

The Rapp-Hodgkin syndrome.

We report on a family with the Rapp-Hodgkin ectodermal dysplasia syndrome. Four affected family members are described and a review of the literature is given.

Cranial fasciitis.

We present the clinical, roentgenographic, light-microscopic, immunohistochemical, and ultrastructural findings in two children with cranial fasciitis. A 7-year-old boy and a 3-year-old girl presented with rapidly expanding masses on the scalp. Roentgenographic studies showed erosion of the underlying cranium in one case. Both lesions showed proliferations of elongated spindle cells in a focally myxoid matrix, together with areas of hemorrhage, vascular proliferation, and chronic inflammation. Occasional cells with atypical nuclei were observed, but mitotic figures were uncommon. Immunoperoxidase studies showed negative or equivocal staining for desmin, factor VIII-associated antigen, S100 protein, and macrophage antigen. In one lesion there was focal positivity for alpha 1-antichymotrypsin, and in another lesion, some cells stained positively for smooth-muscle actin. Electron microscopy showed cells with dilated endoplasmic reticulum, bundles of microfilaments, pinocytotic vesicles, and focal external membrane material, features of myofibroblasts. Both lesions were excised and there has been no recurrence in 7 years in one case and 1 year in the other case. Cranial fasciitis is closely related to nodular fasciitis, but it has a predilection for the scalp of children. Despite its rapid growth, it has a benign clinical course and is cured by excision with or without curettage of the underlying bone. Our immunohistochemical and ultrastructural observations indicate that, like nodular fasciitis, cranial fasciitis represents a proliferation of fibroblasts and myofibroblasts.