Is Ki-67, keratin 16, involucrin, and filaggrin immunostaining sufficient to diagnose inflammatory linear verrucous epidermal nevus? A report of eight cases and a comparison with psoriasis vulgaris

Abstract: Inflammatory linear verrucous epidermal nevus and linear psoriasis are sometimes hard to differentiate clinically and pathologically. Although immunohistochemical expression of keratin 10 (K10), K16, Ki-67, and involucrin may be useful for differentiating both entities, these results have been reported in only a few cases. We collected data from 8 patients with inflammatory linear verrucous epidermal nevus, 11 with psoriasis vulgaris, and 8 healthy controls and evaluated immunohistochemical expression of Ki-67, K16, involucrin, and filaggrin among them. Ki-67 and K16 overexpression was similar in inflammatory linear verrucous epidermal nevus and psoriasis vulgaris compared with normal skin. Although staining for involucrin showed discontinuous expression in parakeratotic regions in 4 inflammatory linear verrucous epidermal nevus cases, it was continuous in the other 4 cases and in all psoriasis vulgaris cases. Filaggrin expression was present in hyperkeratotic regions but scarce in parakeratotic areas in both inflammatory linear verrucous epidermal nevus and psoriasis vulgaris. The immunostaining pattern of Ki-67, K16, involucrin, and filaggrin may be insufficient to discriminate inflammatory linear verrucous epidermal nevus from psoriasis vulgaris.

Skin barrier in atopic dermatitis: beyond filaggrin

Abstract: Atopic dermatitis is a chronic inflammatory skin disease with a complex pathogenesis, where changes in skin barrier and imbalance of the immune system are relevant factors. The skin forms a mechanic and immune barrier, regulating water loss from the internal to the external environment, and protecting the individual from external aggressions, such as microorganisms, ultraviolet radiation and physical trauma. Main components of the skin barrier are located in the outer layers of the epidermis (such as filaggrin), the proteins that form the tight junction (TJ) and components of the innate immune system. Recent data involving skin barrier reveal new information regarding its structure and its role in the mechanic-immunological defense; atopic dermatitis (AD) is an example of a disease related to dysfunctions associated with this complex.

Nestin down-regulation of cortical radial glia is delayed in rats submitted to recurrent status epilepticus during early postnatal life / Atraso no desaparecimento da nestina na glia radial cortical de ratos submetidos a recorrentes status epilepticus durante o desenvolvimento pós-natal precoce

OBJECTIVE: Nestin is temporarily expressed in several tissues during development and it is replaced by other protein types during cell differentiation process. This unique property allows distinguishing between undifferentiated and differentiated cells. This study was delineated to analyze the temporal pattern of nestin expression in cortical radial glial cells of rats during normal development and of rats submitted to recurrent status epilepticus (SE) in early postnatal life (P). METHOD: Experimental rats were submitted to pilocarpine-induced SE on P7-9. The cortical temporal profile of nestin was studied by immunohistochemistry at multiple time points (P9, P10, P12, P16, P30 and P90). RESULTS: We observed delayed nestin down-regulation in experimental rats of P9, P10, P12 and P16 groups. In addition, few radial glial cells were still present only in P21 experimental rats. CONCLUSION: Our results suggested that SE during early postnatal life alters normal maturation during a critical period of brain development.

OBJETIVO: A nestina, temporariamente expressa em diversos tecidos durante o desenvolvimento, é substituída no processo de diferenciação celular, o que permite a distinção entre células diferenciadas e indiferenciadas. O objetivo deste estudo foi verificar o padrão temporal da expressão da nestina nas células da glia radial cortical de ratos durante o desenvolvimento normal e nos ratos submetidos a sucessivos status epilepticus (SE) no periodo pós-natal precoce (P). MÉTODO: Os animais foram submetidos ao SE induzido pela pilocarpina em P7-9. O perfil temporal da nestina foi estudado por imuno-histoquímica em P9, P10, P12, P16, P30 e P90. RESULTADOS: Nos ratos experimentais, observamos atraso no desaparecimento da nestina nos grupos P9, P10, P12 e P16. Ainda, encontramos algumas glias radiais corticais apenas em P21 experimental. CONCLUSÃO: Nossos resultados sugerem que o SE durante o desenvolvimento pós-natal precoce altera o processo de maturação durante um periodo crítico do desenvolvimento encefálico.

Expression of nestin and vimentin in gliomatosis cerebri / Expressão de nestina e vimentina na gliomatosis cerebri

Gliomatosis cerebri (GC) is a rare form of CNS neoplasia in which there is diffuse involvement of the nervous tissue with or without the presence of tumor mass. The origin of the tumor is unknown, nor whether it represents a disease with diffuse onset or infiltration from a neoplastic focus. Here we studied the histopathologic characteristics of 6 cases with a diagnosis of GC and performed an immunohistochemical analysis using glial fibrillary acidic protein (GFAP), synaptophysin, nestin and vimentin. Most tumor cells were negative for GFAP, even though there were foci of positivity for this marker in all cases. We detected the presence of many positive cells for nestin and vimentin in all studied samples. The presence of these cells may indicate origin of the tumor from undifferentiated cells with a high degree of mobility.

A gliomatosis cerebri (GC) é uma forma rara de neoplasia do sistema nervoso central em que existe o envolvimento difuso do tecido nervoso com ou sem a presença de massa tumoral. A origem do tumor é incerta, bem como se representa uma doença de início difuso ou uma infiltração a partir de um foco de neoplasia. Foram estudadas as características histopatológicas de seis casos com diagnóstico de GC e realizada imuno-histoquímica utilizando-se GFAP, sinaptofisina, nestina e vimentina. A maioria das células tumorais mostrou-se negativa para GFAP, apesar de existirem focos de positividade para este marcador em todos os casos. Observamos muitas células positivas para nestina e para vimentina em todas as amostras estudadas. Estas células poderiam indicar a origem do tumor em células multipotenciais com alto grau de mobilidade.

Componente oligodendroglial e neuronal em glioblastomas: possível relação com o prognóstico / Oligodendroglial and neuronal component in glioblastomas: possible relation with prognosis

Glioblastomas são tumores astrocíticos de alto grau de malignidade e o diagnóstico baseado nos critérios histológicos atuais não tem explicado a maior sobrevida observada em alguns casos. A presença de um componente oligodendroglial foi proposta mais recentemente como um possível indicador de maior sobrevida, tanto pela OMS quanto pela classificação de Sainte Anne 2000. Esta última propõe ainda que um componente neuronal está relacionado com maior sobrevida. O objetivo deste estudo foi rever tumores de 40 pacientes diagnosticados como glioblastomas pelos critérios da OMS, com o propósito de identificar: a presença de um componente oligodendroglial utilizando critérios morfológicos; a presença de um componente neuronal utilizando marcadores imuno-histoquímicos (anticorpos anti-neurofilamento e sinaptofisina). Objetivou-se também correlacionar os achados histológicos e imuno-histoquímicos com a sobrevida dos pacientes, estudando também outras variáveis que podem ter influência na sobrevida. Foram identificados 11 tumores com componente oligodendroglial e 7 com componente neuronal. Apesar do pequeno número de casos estudados, a presença de um componente oligodendroglial associou-se com maior sobrevida. O valor da expressão de marcadores neuronais em gliomas malignos precisa ser confirmado com a avaliação de séries maiores.

PKC alpha induces differentiation through ERK1/2 phosphorylation in mouse keratinocytes

Epidermal keratinocyte differentiation is a tightly regulated stepwise process that requires protein kinase C (PKC) activation. Studies on cultured mouse keraitnocytes induced to differentiate with Ca2+ have indirectly implicated the involvement of PKC alpha isoform. When PKC alpha was overexpressed in undifferentiated keratinocytes using adenoviral system, expressions of differentiation markers such as loricrin, filaggrin, keratin 1 (MK1) and keratin 10 (MK10) were increased, and ERK1/2 phosphorylation was concurrently induced without change of other MAPK such as p38 MAPK and JNK1/2. Similarly, transfection of PKC alphakinase active mutant (PKC alpha- CAT) in the undifferentiated keratinocyte, but not PKC beta-CAT, also increased differentiation marker expressions. On the other hand, PKC alphadominant negative mutant (PKC beta-KR) reduced Ca2+ -mediated differentiation marker expressions, while PKC beta-KR did not, suggesting that PKC alphais responsible for keratinocyte differentiation. When downstream pathway of PKC alphain Ca2+ - mediated differentiation was examined, ERK1/2, p38 MAPK and JNK1/2 phosphorylations were increased by Ca2+ shift. Treatment of keratinocytes with PD98059, MEK inhibitor, and SB20358, p38 MAPK inhibitor, before Ca2+ shift induced morphological changes and reduced expressions of differentiation markers, but treatment with SP60012, JNK1/2 inhibitor, did not change at all. Dominant negative mutants of ERK1/2 and p38 MAPK also inhibited the expressions of differentiation marker expressions in Ca2+ shifted cells. The above results indicate that both ERK1/2 and p38 MAPK may be involved in Ca2+- mediated differentiation, and that only ERK1/2 pathway is specific for PKCa-mediated differentiation in mouse keratinocytes.

Activation of Embryonic Intermediate Filaments Contributes to Glial Scar Formation after Spinal Cord Injury in Rats

The expression of two intermediate filaments, nestin and vimentin, was studied in spinal cord injury (SCI) to elucidate their roles in the formation of glial scars. Rats were sacrificed 1, 4, and 7 days after induction of compression injury of the spinal cord using an aneurysm clip. The affected spinal cords were studied using antibodies against nestin and vimentin intermediate filaments. One day after spinal cord injury, some clusters of nestin-positive vessels were detected in the center of the injury, but few were seen in other cell types. Vimentin immunostaining was detected in some glial cells in the center and its level of immunoreactivity was enhanced in the ependymal cells of the central canal. On days 4 and 7 after spinal cord injury, astrocytes and some ependymal cells in the central canal were stained positively for nestin and increased expression of nestin was observed in vessels. Vimentin was detected in some macrophages and astrocytes in the lesions. Nestin was co-localized with glial fibrillary acidic protein in some glial cells in SCI. These findings imply that spinal cord cells in adult animals have embryonic capacity, and these cells are activated after injury, which in turn contributes to repair of spinal cord injury through formation of a glial scar.

Utility of Thyroid Transcription Factor-1 and Cytokeratin 20 in Identifying the Origin of Metastatic Carcinomas of Cervical Lymph Nodes

The identification of primary location of a metastatic tumor is a difficult diagnostic problem and sometimes can be facilitated by the use of immunohistochemical markers. Thyroid transcription factor-1 (TTF-1) is a 38-kDa nuclear homeodomain transcription factor that is expressed specifically in lung or thyroid neoplasms. Cytokeratin 20 (CK20) is a 46-kDa low-molecular-weight cytokeratin that shows restricted expression in adenocarcinomas of the gastrointestinal tract (GIT) and transitional cell carcinomas of the urinary tract. We studied the immunohistochemical expression of TTF-1 and CK20 in 68 metastatic carcinomas in cervical lymph nodes. The primary sites were the lung in 29 cases, stomach in 13, colorectum in 3, and other sites in 23. TTF-1 expression was detected in 69.0% of metastatic lung carcinomas and none in metastatic GIT carcinomas, whereas CK20 expression was detected in 68.8% of metastatic GIT carcinomas and none of metastatic lung carcinomas. TTF-1 had a specificity of 0.95 and a sensitivity of 0.69 for metastatic lung carcinoma, whereas CK20 had a specificity of 1.00 and a sensitivity of 0.69 for metastatic GIT carcinoma. These results indicate that TTF-1 and CK20 should be the first choice as a component of antibody panel to prove or to exclude the lung and GIT origin, respectively, especially in patients presenting with metastatic carcinomas of unknown primary site.

The Nerve-dependency of Merkel Cell Proliferation in Cultured Human Fetal Glabrous Skin

Merkel cells are thought to function as slowly adapting mechanoreceptors and are known as targets for sensory nerves. However, the nerve-dependency of Merkel cells remains controversial. In this respect, some investigators have found interregional differences between hairy and glabrous skin and others have shown intraregional differences within denervated rat touch domes. Differences between species have also been reported. This study was performed to determine whether Merkel cells proliferate in vitro in the absence of the systemic factors, blood vessels and the intact nerves in human skin. Suspension organ culture was performed using fetal digits to investigate their in vitro proliferation. Merkel cells and cutaneous nerves were identified using antibodies to cytokeratin 20 and protein gene product 9.5 (PGP 9.5), respectively. Fetal digits of 56-82 day gestational age were cultured in serum free medium in a high O2 (45%) environment. Tissues were harvested before starting culture (D0) and 1,4,7,14, 28d after culture. Merkel cells were observed in the volar pads and dorsal nail matrices at D0. After 28d of suspension organ culture, digits looked healthy structurally and the number of Merkel cells had increased. However, PGP 9.5-immunoreactive nerves were markedly diminished after 1 day of culture and almost disappeared after 4 days. Merkel cell proliferation in vitro suggested that Merkel cell development is probably nerve-independent in human fetal glabrous skin.

Colonic adenocarcinoma metastatic to the thyroid gland: a case report with immunohistochemical investigation

Clinically evident metastases of carcinomas to the thyroid gland are rare, particularly from a colorectal primary tumor. We present a case of colonic adenocarcinoma metastatic to the thyroid gland with histopathologic and immunohistochemical findings. A 68-year-old woman with a history of Dukes' stage B colon carcinoma presented a mass in the thyroid gland. The tumor was confirmed to be metastatic adenocarcinoma from the colon. The immunohistochemical findings demonstrated positive staining for cytokeratin 20, low-molecular-weight cytokeratin, villin and carcinoembryonic antigen, but stains were negative for cytokeratin 7 and thyroglobulin.

Cellular components of proliferative vitreoretinal membranes

To understand the pathogenesis of proliferative vitreoretinal membrane formation which occurs in proliferative vitreoretinopathy (PVR) and proliferative diabetic retinopathy (PDR), etc., accurate identification of the cellular components of the membrane is needed. This study was performed to identify cellular components of the membranes by means of immunohistochemical technique. 11 proliferative vitreoretinal membranes which were surgically obtained from 7 eyes with PVR and 4 eyes with PDR were stained with monoclonal antibodies against cytokeratin, glial fibrillary acidic protein (GFAP), or vimentin using immunoperoxidase technique (ABC method). In the PVR membranes, mean cell positivities for cytokeratin, GFAP and vimentin were 48%, 1% and 92%, respectively and in the PDR membranes, 0%, 5% and 93%, respectively. The above results suggest that retinal pigment epithelial cells and fibroblasts are major cellular components of PVR membranes, and that mesenchymal cells are major cellular components and glial cells are minor cellular components of PDR membranes.