Mucopolysaccharide polysulfate increases local skin blood volume through nitric oxide production.

BACKGROUND: Mucopolysaccharide polysulfate (MPS) is widely used as an active ingredient in topical preparations for the treatment of asteatosis and blood flow disorders. Although topical MPS products can increase cutaneous blood flow (CBF), the underlying mechanism remains unclear. OBJECTIVE: In this study, we aimed to elucidate how MPS increases CBF. We investigated the association of nitric oxide (NO), a powerful mediator associated with increased local blood volume, with the blood flow-accelerating action of MPS in mice. In addition, we verified the effects of MPS on NO production in different skin cell types, such as keratinocytes (KCs), endothelial cells (ECs), and dermal fibroblasts (DFs). METHODS: We used raster-scanning optoacoustic imaging mesoscopy to observe in vivo changes in the skin blood volume. NO production was determined in each cell using an NO indicator. An enzyme-linked immunoassay was used to measure the phosphorylated nitric oxide synthase (NOS) levels in ECs, DFs, and KCs in the presence or absence of MPS. RESULTS: Topical application of MPS increased the skin blood volume in mice, and this increase was abolished through the addition of NOS inhibitors. MPS promoted the dose-dependent production of NO in various cells, which caused alterations in the phosphorylation state of NOS. CONCLUSION: Our findings demonstrate that MPS promotes an increase in skin blood volume and NO production in various skin cell types. These results suggest that MPS can potentially accelerate CBF through the NO biosynthesis pathway in different skin cell types.

The Effects of Mucopolysaccharide Polysulfate on Steroid-Induced Tight Junction Barrier Dysfunction in Human Epidermal Keratinocytes and a 3D Skin Model.

INTRODUCTION: The long-term use of topical corticosteroids (TCS) is associated with side effects such as skin atrophy and barrier deterioration. Moisturizers, such as mucopolysaccharide polysulfate (MPS), have been reported to prevent relapses in atopic dermatitis (AD) when used in combination with TCS. However, the mechanisms underlying the positive effects of MPS in combination with TCS in AD are poorly understood. In the present study, we investigated the effects of MPS in combination with clobetasol 17-propionate (CP) on tight junction (TJ) barrier function in human epidermal keratinocytes (HEKa) and 3D skin models. METHODS: The expression of claudin-1, which is crucial for TJ barrier function in keratinocytes, and transepithelial electrical resistance (TEER) was measured in CP-treated human keratinocytes incubated with and without MPS. A TJ permeability assay, using Sulfo-NHS-Biotin as a tracer, was also conducted in a 3D skin model. RESULTS: CP reduced claudin-1 expression and TEER in human keratinocytes, whereas MPS inhibited these CP-induced effects. Moreover, MPS inhibited the increase in CP-induced TJ permeability in a 3D skin model. CONCLUSION: The present study demonstrated that MPS improved TJ barrier impairment induced by CP. The improvement of TJ barrier function may partially be responsible for the delayed relapse of AD induced by the combination of MPS and TCS.

A single pretreatment with clofibric acid attenuates carbon tetrachloride-induced necrosis, but not steatosis, in rat liver.

The present study investigated whether a single pretreatment with clofibric acid suppresses liver injury in rats after CCl4 intoxication. Rats received a single pretreatment with clofibric acid (100 mg/kg, i.p.) 1 h prior to a CCl4 (1 mL/kg, p.o.) challenge, and were euthanized 24 h after the CCl4 administration. A single pretreatment with clofibric acid effectively suppressed increases in the serum aminotransferase activities and the severity of necrosis following the CCl4 challenge, whereas the pretreatment did not protect against CCl4-induced fatty liver. The clofibric acid pretreatment did not affect blood concentrations of CCl4 in the early stage after CCl4 dosing, or the level of the CCl4 reaching the liver 1 h after the CCl4 challenge. Moreover, the clofibric acid pretreatment did not affect the intensity of the covalent binding of the [14C]CCl4 metabolite to microsomal proteins and lipids. The clofibric acid pretreatment did not alter microsomal cytochrome P450 2E1 activity. Based on these results, we conclude that protection against CCl4-induced hepatocellular necrosis by a clofibric acid pretreatment does not require its repeated administration, and that a single and brief pre-exposure to clofibric acid prior to CCl4 dosing markedly suppresses necrosis without affecting the development and progression of steatosis.

Importance of Water Content of the Stratum Corneum in Mouse Models for Contact Hypersensitivity.

Although a marked rise in the prevalence of allergic diseases over the past few decades may be related to environmental factors in industrialized countries, evidence for the protective effect of humidity on the barrier function of the skin is still awaited. We asked whether an increase in the water content of stratum corneum at the site of hapten application had a strong impact on the magnitude of contact hypersensitivity (CHS). The magnitude of CHS, induced by either lipid-soluble or water-soluble hapten, was inversely correlated with the water content of stratum corneum at the hapten application site in the elicitation phase. An increase in the water content induced by exposure to high humidity for 6 hours was sufficient to ameliorate the magnitude of CHS even in mice with the genetic defect in attenuating the CHS responses, such as flaky tail mice. The reduced CHS was associated with downregulation of IL-1α, IL-4, and IFN-γ mRNA expression. Epicutaneously applied hapten can penetrate more readily through the stratum corneum with lower water content than that with higher water content, even after tape-stripping. These findings indicate that increased levels of water in the stratum corneum serve to ameliorate the CHS beyond the genetic effects.

Epidermal Neuromedin U Attenuates IgE-Mediated Allergic Skin Inflammation.

Although keratinocyte-derived neuropeptide neuromedin U (NMU) mediates the proinflammatory effects of innate-type mast cell activation, no information is available on the physiological roles. Here, to investigate the effects of NMU on IgE-mediated allergic skin inflammation, we determined whether IgE-mediated inflammation associated with severe scratching was induced in Nmu-/- mice administered repeated hapten applications to the ear or footpad. Dry skin was induced by targeted deletion of Nmu. Mice administered repeated hapten application developed IgE-mediated allergic inflammation characterized by severe scratching and increased serum IgE levels only when the ear, and not the footpad, was subjected to scratching, indicating that depletion of NMU from the epidermis alone does not drive such allergic inflammation. Thus, the susceptibility of Nmu-/- mice to allergic inflammation depends primarily on scratching dry skin. Further, allergic skin inflammation mediated by FcεRI cross-linking in Nmu-/-mice was inhibited by prior injection of NMU. These results indicate that NMU plays an important physiological role as a negative regulator during the late stage of IgE-mediated allergic skin inflammation.

A spontaneously occurring malignant pituicytoma in a male sprague dawley rat.

Pituicytoma is an extremely rare neoplasm derived from pituicytes, which are glial cells in the posterior lobe of the pituitary gland. A malignant pituicytoma was found in the intracranial cavity of a 55-week-old male Sprague-Dawley rat. Macroscopically, the tumor was located on the sphenoid bone and involved the pituitary gland. The tumor was composed of sheets of fusiform cells with spindle- or pleomorphic-shaped nuclei and abundant eosinophilic cytoplasms. The cells were arranged in a whirling or irregular growth pattern. Some tumor cells were bizarre multinucleated giant cells with cytoplasmic eosinophilic hyaline droplets. Many tumor cells were strongly positive for vimentin and glial fibrillary acidic protein, and some cells were positive for ED-1 and S-100. These findings closely resembled those of a giant cell glioblastoma derived from the pituitary gland, suggesting anaplastic pituicytoma. From our review of the literature, we believe this is the first report of a spontaneous malignant pituicytoma in a rodent.

The 14-day repeated dose liver micronucleus test with methapyrilene hydrochloride using young adult rats.

The repeated dose liver micronucleus (RDLMN) assay using young adult rats has the potential to detect genotoxic hepatocarcinogens that can be integrated into a general toxicity study. The assay methods were thoroughly validated by 19 Japanese facilities. Methapyrilene hydrochloride (MP), known to be a non-genotoxic hepatocarcinogen, was examined in the present study. MP was dosed orally at 10, 30 and 100mg/kg/day to 6-week-old male Crl:CD (SD) rats daily for 14 days. Treatment with MP resulted in an increase in micronucleated hepatocytes (MNHEPs) with a dosage of only 100mg/kg/day. At this dose level, cytotoxicity followed by regenerative cell growth was noted in the liver. These findings suggest that MP may induce clastogenic effects indirectly on the liver or hepatotoxicity of MP followed by regeneration may cause increase in spontaneous incidence of MNHEPs.

Defective sweating responses in atopic dermatitis.

While sweat is thought to be one of the important factors provoking exacerbations of clinical symptoms in atopic dermatitis (AD), little attention has been drawn to a beneficial role of sweat in the development of AD lesions. However, if the permeability barrier and antimicrobial barrier dysfunction represents the primary event in the development of AD, an evaluation of sweating responses in AD is a logical place to look for changes that predispose to the disease. In this regard, there have been conflicting data regarding whether sweating responses are impaired, normal or enhanced in AD patients. Consistent with the results of most recent studies, our recent study showed that most AD patients exhibit a defective ability to deliver sweat to the skin surface in response to thermal stress. Despite such defective sweating responses observed in the most part, a marked augmentation in the sweating response with delayed kinetics can be paradoxically detected in some sweating glands of these AD patients, indicating compensatory hyperhidrosis. Dermcidin, a new antimicrobial peptide exclusively produced by sweat glands, was abundantly detected not only in the sweat glands and ducts, and the lumen, but also in the dermal tissues adjacent to the sweat glands. These results indicate that the sweat may be retained in the lumen or pour into the dermal tissues, thereby causing inflammation. Thus, chronic inflammation in AD may be caused in part by a dysfunction of the sweat delivery system.

[A study of mental health in community-dwelling older persons].

We conducted a comprehensive evaluation of the mental health of community-dwelling elderly people, and encompassed the physiological, psychological, social and environmental aspects of their lives. The study used a questionnaire similar to the one used by Matsubayashi et al in their study in Kahoku-cho. The Japanese version of General Health Questionnaire 12 (GHQ-12) was used to evaluate mental health. Responses were received from 2,799 (81.5%) of 3,432 Numura-cho residents. After eliminating inadequate responses, 1,298 (37.8%) (586 men and 712 women) were analyzed. By setting mental health disorder, defined as a value of GHQ-12 exceeding 4.0, as the target variable, logistic regression analysis was conducted using the background factors as explanatory variables. Information related function (odds ratio: 0.45; 95% CI: 0.30-0.66), living with others (0.36, 0.14-0.94), presence of spouse (2.52, 1.14-5.59), economic condition (0.45, 0.22-0.91), family relationship (0.17, 0.05-0.52), work & sports (0.31, 0.14-0.67) and emotional support (0.67, 0.48-0.95) were found to be explanatory variables for mental health in the young elderly; as were activities of daily living (0.52, 0.35-0.79), Information related function (0.56, 0.35-0.90) and emotional support (0.37, 0.24-0.58) in the old elderly; as were activities of daily living (0.37, 0.19-0.70) and economic condition (0.32, 0.11-0.95) in the very old. For amelioration of the mental health of elderly persons living in the community, attempts should be made to improve the background factors clarified by the present study by efficiently utilizing health, medical and welfare services.