Biomedical subjects

Masahiko Toyoda

Publications and source records attributed to Masahiko Toyoda.

11 recordsLinked to original sources

PubMed2005

Investigation of the topical application of procyanidin oligomers from apples to identify their potential use as a hair-growing agent.

BACKGROUND: Procyanidins are a family of condensed tannins, which have been shown to possess hair-growing activity in both the in vitro and in vivo murine models. AIMS: We report a 12-month clinical study aimed at treating male pattern baldness by external application of 0.7% apple procyanidin oligomers. PATIENTS/METHODS: A double-blind clinical test involving a total of 43 subjects was performed. Twenty-one men in the procyanidin group and 22 men in the placebo control group were subjected to analysis. In the first 6 months, we compared the procyanidin and the placebo groups to assess the medicinal effects of procyanidin oligomers. The application time of the procyanidin group was subsequently extended to 12 months, and the time course of its remedial value was examined. RESULTS: The increase in total number of hairs in a designated scalp area of the procyanidin group subjects after the 6-month trial was significantly greater than that of the placebo control group subjects (procyanidin, 3.3 +/- 13.0 (mean +/- SD)/0.50 cm(2); placebo, -3.6 +/- 8.1/0.50 cm(2); P < 0.001, two-sample t-test). Time course-dependent improvement in hair density was observed in the procyanidin subjects. No adverse side effects were observed in any of the subjects. Procyanidin therapy thus shows potential hair-growing activity.

Journal Article↗

PubMed2004

Ultrastructural characterization of the distribution of melanin and epidermal macrophages in photodamaged skin.

We examined the characteristics of melanin distribution, the possible mechanisms underlying the histological incontinence of pigment, and the significance of epidermal macrophages in photodamaged skin. We used electron microscopy to compare and quantitate melanin distribution in various types of cells and structures, to qualitatively observe associations of melanin granules with melanophages, and to examine morphological differences of epidermal macrophages in sun-exposed versus sun-protected facial skin. Melanin-containing cells (such as Langerhans' cells) and melanin-containing structures (such as colloid bodies) in photodamaged skin were more numerous than in sun-protected skin, in proportion to differences in melanocyte density and in epidermal melanin content. Although the precise mechanism(s) of histological incontinence of pigment in photoaging skin appear to be very complicated, it is certainly one of the morphological hallmarks of photodamaged facial skin, and the degeneration of keratinocytes (noted by their electron-lucent properties), a feature characteristic of photoaging, contributes to that process. Furthermore, the increased numbers of epidermal macrophages in sun-exposed skin may be associated with photoaging processes (probably through their phagocytic function) as well as alterations of the cutaneous immune system.

Aged↗

PubMed2003

Upregulation of activin A gene by butyrate in human colon cancer cell lines.

Activin A has been reported to play a role in the progression of colorectal cancer. Because dietary fiber protects against colorectal cancer, we hypothesized that butyrate, a fermentation product of dietary fiber, may affect the expression of activin A in colon cancer cells. Semiquantitative RT-PCR demonstrated that the activin A gene was upregulated by sodium butyrate in the human colon cancer cell lines HT-29 and Caco-2 in a concentration- and time-dependent manner. However, the activin A gene did not respond to sodium butyrate in the human normal colonic cell line FHC, rat normal intestinal epithelial cell (IEC) line IEC-6, and the explant of rat colon. Flow cytometry and agarose gel electrophoresis of genomic DNA revealed that cell cycle arrest and apoptosis were induced by sodium butyrate but not exogenous activin A in HT-29 cells, indicating that activin A could not act as an autocrine factor in colon cancer cells. By assuming that activin A promotes colorectal cancer spread as a paracrine factor, our findings suggest that butyrate could act as a tumor promoter in some circumstances.

Activins↗

PubMed2003

Neuropeptides concentrations in the skin of a murine (NC/Nga mice) model of atopic dermatitis.

BACKGROUND: It has been reported that the expression of neuropeptides (NPs), and the density and structure of peripheral nerves in atopic dermatitis (AD) are different from those in normal skin. OBJECTIVE: We investigated the role of NPs, in the development of AD with quantitative study of substance P (SP) and calcitonin gene-related peptide (CGRP) in the skin of AD-model mice. METHODS: We measured the NPs in the skin of mice (NC/Nga as AD-model mice, BALB/c and C57BL/6 as control) by enzyme-linked immunosorbentassay (ELISA). Peripheral nerve fibers and SP in the skin were stained by immunohistochemical staining, using anti-PGP9.5 antibody and anti-SP antibody. RESULTS: Under conventional condition, SP concentration in AD-like skin lesions of NC/Nga mice was higher than that in non-affected skin of the same mice. Under specific pathogen-free condition, SP concentration in the skin of NC/Nga mice was higher than that in the skin of BALB/c and C57BL/6 mice. In contrast, CGRP concentration in the skin lesions was lower than that in non-affected skin of NC/Nga mice. SP was detected not only in the nerve fibers in the dermis but also in mast cells in the inflammatory areas. CONCLUSIONS: The skin of NC/Nga mice contains more SP congenitally, and environmental factors may aggravate this abnormal condition. We hypothesize that increase of SP accompanied with a decrease of CGRP in the skin may play important roles in the pathogenesis and development of AD.

Animals↗

PubMed2003

New aspects in acne inflammation.

There is ample clinical evidence suggesting that the nervous system such as emotional stress can influence the course of acne. We examined possible participation of cutaneous neurogenic factors including neuropeptides, neuropeptide-degrading enzymes and neurotrophic factors, in association with inflammation in the pathogenesis of acne. Immunohistochemical studies revealed that substance P (SP)-immunoreactive nerve fibers were in close apposition to the sebaceous glands, and that neutral endopeptidase (NEP) was expressed in the germinative cells of the sebaceous glands in the skin from acne patients. Nerve growth factor showed immunoreactivity only within the germinative cells. In addition, an increase in the number of mast cells and a strong expression of endothelial leukocyte adhesion molecule-1 on the postcapillary venules were observed in adjacent areas to the sebaceous glands. In vitro, the levels and the expression of stem cell factor by fibroblasts were upregulated by SP. When organ-cultured normal skin specimens were exposed to SP, we observed significant increases in the sizes of the sebaceous glands and in the number of sebum vacuoles in sebaceous cells. Furthermore, supplementation of SP to organ-cultured skin induced expression of NEP, and we demonstrated the subcellular localization of NEP in the endoplasmic reticulum and the Golgi apparatus within the sebaceous germinative cells using preembedding immunoelectron microscopy. These findings suggest that SP may stimulate lipogenesis of the sebaceous glands which may be followed by proliferation of Propionibacterium acnes, and may yield a potent influence on the sebaceous glands by provocation of inflammatory reactions via mast cells. Thus, cutaneous neurogenic factors should contribute to onset and/or exacerbation of acne inflammation.

Acne Vulgaris↗

PubMed2003

Expression of hornerin in stratified squamous epithelium in the mouse: a comparative analysis with profilaggrin.

We have recently identified a novel protein named hornerin, the structural features of which are most similar to those of profilaggrin, an essential protein for keratinization of epidermal tissues. In this study we examined the expression of hornerin compared with that of profilaggrin in various mouse tissues. Hornerin was expressed in the upper epidermis of newborn mouse skin, as was profilaggrin. In addition, both hornerin and profilaggrin were expressed in the tongue, esophagus, and forestomach. In all four tissues, immunostaining for hornerin and profilaggrin showed a granular pattern, and most of the signals for the two proteins were co-localized on keratohyalin granules. This was confirmed by double immunoelectron microscopy. Within keratohyalin granules, hornerin was detected more frequently in the periphery, whereas profilaggrin was equally distributed. A quantitative RT-PCR revealed that both genes were expressed at highest levels in the forestomach and at the next highest levels in skin. Profilaggrin mRNA was most abundant in the forestomach. In skin, the amount of hornerin mRNA was more than fourfold greater than the amount of profilaggrin mRNA. These results form the basis for a better understanding of possible overlapping and/or differential functions of hornerin and profilaggrin.

Animals↗

PubMed2002

Characterization of the cysteine-rich calcium-binding S100A3 protein from human hair cuticles.

S100A3, a unique protein among all members of the calcium-binding S100 family, is specifically expressed at the inner endocuticle of human hair fibers. Upon hair damage, S100A3 is released from hair fibers and possibly destabilizes the hair tissue architecture. This study describes the purification and characterization of native S100A3 isolated from human hair fibers. We extracted native S100A3 from cuticles and purified the protein by anion-exchange chromatography. The results of 2D gel electrophoresis showed that cuticle S100A3 has a slightly lower isoelectric point compared to the recombinant protein. Tandem mass spectrometry of the peptides resulting from endoproteinase digest of cuticle S100A3 revealed that the N-terminal methionine is replaced with an acetyl group. This is the first report on biochemical characteristics of S100A3 in hair cuticle.

Calcium-Binding Proteins↗

PubMed2002

Morphological analysis of skin in senescence-accelerated mouse P10.

Senescence-accelerated mice (SAM) were established as a kind of group of related inbred strains that have been used as animal models for accelerated senescence and age-associated disorders. To analyze the characteristics of skin in SAM, the present study examined its morphology at the histological and ultrastructural levels. Histologic comparison of skin from senescence-accelerated-prone (SAM P10) and -resistant (SAM R1) mice revealed that the most characteristic features of SAM P10 were remarkable increases in the number of mast cells and in the density of collagen fibers in the dermis. Therefore, cutaneous allergic responsiveness and the proliferative activity of fibroblasts were also examined. Ultrastructurally, mast cells in the skin of SAM P10 possessed specific granules which exhibited considerable heterogeneity in electron density and various degrees of degranulation. In contrast, mast cells in the skin of control SAM R1 possessed a population of stable granules. Mast cell granules were frequently in contact with fibroblasts and were in close apposition to collagen fibers in the dermis of SAM P10. The collagen bundles were disorganized, and various diameters of collagen fibers were observed. SAM P10 demonstrated a significantly reduced wheal-and-flare reaction to histamine and tachykinins such as substance P, which suggests that skin aging may cause reduced sensitivity of mast cells and/or blood vessels to extrinsic stimuli. An in-vitro study using organ and monolayer culture demonstrated that the proliferative capacity of fibroblasts in the skin of SAM P10 was reduced in comparison with SAM R1. This is the first report that demonstrates the detailed morphological characteristics of skin in SAM P10. The findings obtained suggest that SAM P10 is a useful animal model of aged human skin, because of its many similar morphological features, including the reduction of the cutaneous allergic response, represented by neurogenic inflammation via the axon reflex, and its decreased fibroblast proliferation.

Aging, Premature↗

PubMed2002

Label-retaining cells in the bulge region are directed to cell death after plucking, followed by healing from the surviving hair germ.

Hair plucking is the most frequently used method of anagen induction within hair follicles. In this study, we found that plucking leads to the entire renewal of the follicular stem cell region of the mouse pelage follicle. Comparative histochemical analysis revealed that S100A4 protein was specifically distributed in the outer layer of the epithelial sac, which has been identified as the stem cell region of the pelage follicle, whereas the slow cycling cells that retained 5-bromo-2'-deoxyuridine label for 8 wk were located in the epithelial sac and also in the hair germ. Combined terminal deoxynucleotide transferase deoxyuridine triphosphate fluorescein nick end labeling method and immunohistochemistry revealed that positive cells were detected in the outer layer of the epithelial sac possessing both bromo-2'-deoxyuridine and S100A4 labels 4.5 h after plucking. No terminal deoxynucleotide transferase deoxyuridine triphosphate fluorescein nick end labeling signal, however, was observed in the hair germ. Serial inspection of the plucked follicle revealed that almost all regions of the epithelial sac became terminal deoxynucleotide transferase deoxyuridine triphosphate fluorescein nick end labeling positive 12 h after plucking. Terminal deoxynucleotide transferase deoxyuridine triphosphate fluorescein nick end labeling-positive cells ultimately degenerated without forming apoptotic bodies. Subsequently, the surviving label-retaining cells in the hair germ migrated upward to re-epithelialize the damaged portion. These results indicate that follicular stem cells in the epithelial sac underwent cell death after plucking. It is likely that the hair germ is responsible for the reconstruction of the stem cell region of the hair follicle.

Animals↗

PubMedDate not supplied

Neuropeptides and sebaceous glands.

This review provides a new insight into the participation of neuropeptides, notably substance P (SP), in the pathophysiology of acne. We show morphological alterations of sebaceous glands elicited by SP and differences in expression of various neurogenic factors in association with sebaceous glands in acne-prone versus normal facial skin. In vitro studies reveal that SP promotes both the proliferation and the differentiation of sebaceous glands. SP induces the expression of neutral endopeptidase, a potent neuropeptide-degrading enzyme, in sebaceous germinative cells and of E-selectin by perisebaceous venules. Facial skin from acne patients is characterized by rich innervation, by increased numbers of SP-containing nerves and mast cells, and by strong expression of neutral endopeptidase in sebaceous glands and E-selectin in venules around sebaceous glands, compared with normal skin. Mast cell-derived IL-6 and TNF-alpha, followed by SP-stimulated degranulation, have the potential to induce nerve growth factor expression by sebaceous cells which results in the promotion of innervation and in the expression of E-selectin, respectively. SP enhances mast cell proliferation through up-regulation of stem cell factor expression in fibroblasts. These findings suggest the involvement of neurogenic factors, such as neuropeptides, in the disease process of acne and explain the possible mechanism of the exacerbation of acne from a neurological point of view.

Acne Vulgaris↗

PubMedDate not supplied

Nevus lipomatosus cutaneous superficialis with perifollicular fibrosis.

Nevus lipomatosus cutaneous superficialis (NLCS) is a rare hamartomatous skin lesion histopathologically characterized by the presence of mature fat tissue even within the upper dermis. Clinically, two types of NLCS can be distinguished; a multiple type and a solitary type. We here report a 10-month-old girl showing multiple type NLCS as a collection of a nodule and papules on her right abdomen. Histological examination revealed that the lesion was composed of a lobular proliferation of fat tissue throughout the dermis and immature hair follicle-like structures with perifollicular fibrosis. Histological alterations of the dermal connective tissue components were also seen, including thickening of collagen bundles and increased numbers of both fibroblasts and blood vessels. This is the first reported case of NLCS with perifollicular fibrosis.

Female↗