Immunohistochemical investigation of collagen subtypes in human glioblastomas

Gliofibroma: immunohistochemical analysis

A case of gliofibroma occurring in an adult patient as a large circumscribed supratentorial tumor is reported. The bimorphic pattern was substantiated and further analyzed by immunohistochemistry. Some evidence in favor of collagen production by mesenchymal and/or inflammatory cells leading to a progressive fibrous replacement of the glial cells in this particular tumor type is presented.

Rat glioma cell lines C6 and 9L synthesize type 1 collagen in vitro

Glial cell lines (C6, a glioma and 9L, a gliosarcoma) grown in vitro produce type 1 collagen which is detectable in the extracellular matrix by immunocytochemistry. Northern blot analysis using a cDNA specific for the proalpha2 (I) chain of procollagen indicates the presence of a single transcript with an apparent size of 4.8 kb in the C6 cell line, whereas two transcripts with apparent sizes of 5.8 and 4.8 kb are visualized in the 9L cells. The stimulatory effect of ascorbic acid on collagen production is detectable by a 20-27% increase in the concentration of hydroxyproline in the culture medium from the two glioma cell lines. Therefore these glioma cell lines provide a valuable model system for comparative investigations on the regulation of type 1 collagen synthesis by nonmesenchymal cells of neuroepithelial origin.

Gliofibroma. Case report

The case history of an infant with a large gliofibroma is presented. Gliofibromas are rare mixed glialmesenchymal tumors that have been poorly characterized. The computerized tomography appearance and a detailed light and electron microscopic description are presented, along with immunoperoxidase studies of this tumor. This case is compared with gliofibromas described elsewhere in the literature.

Increased levels of type VIII collagen in human brain tumours compared to normal brain tissue and non-neoplastic cerebral disorders

The expression of type VIII collagen was examined in the normal and diseased human brain. Focal immunoreactivity was seen in histologically abnormal vessels of all four angiomas and 40 of 52 brain tumours (gliomas, meningiomas and schwannomas). An extended staining pattern, as well as a punctate distribution, was frequently observed in affected vessels. Staining was not apparent in nine normal brains and in 15 pathologic brains showing various cerebrovascular abnormalities, including Alzheimer's, Leigh's and Wernicke's diseases. Immunoblotting of glioblastomas revealed two bands at 56 kD and 67 kD which were also present at low levels in normal frontal cortex. The extracellular distribution of type VIII collagen was different from that of the other collagen types which have been described in brain and resembles patterns of expression described for certain tissues during mammalian embryogenesis (Kapoor et al., 1988). Our results provide additional evidence for the participation of type VIII collagen in some types of angiogenesis.

Histogenesis of sarcomatous component of the gliosarcoma: an ultrastructural study

This report describes the ultrastructural findings of the sarcomatous component in five cases of gliosarcoma. The tumor contained a heterogenous population of cells with collagen scattered in the interstitium. Three main cell types were found: histiocyte-like cells, fibroblast-like cells and undifferentiated cells. The histiocyte-like cells had oval nuclei, short and flat rough endoplasmic reticulum, prominent Golgi apparatus, lysosomes, phagocytic vacuoles, ruffled cytoplasmic membrane with filopodia, segmental basal lamina and occasional intercellular junctions. The fibroblast-like cells had elongated nuclei, prominent cisterns of rough endoplasmic reticulum and microfilaments. The undifferentiated cell cytoplasmic processes suggesting differentiation toward histiocyte-like cell. In addition, intermediate cells, myofibroblasts, multinucleated giant cells and xanthomatous cells were also present. Occasional glial processes were interposed between tumor cells. Some were enclosed by cytoplasmic processes of histiocyte-like cells and others engulfed within the cytoplasm. Capillary showed surface infoldings, fenestrations of endothelial cells, thickened basal lamina, occasional pericytes and scattered collagen. Some capillaries were surrounded by aggregating histiocyte-like cells and undifferentiated cells. The present findings suggest that (a) the sarcomatous component in gliosarcoma is likely derived from undifferentiated cells with a broad differentiation into histiocytic, fibroblastic and other cell types, (b) endothelial cells and pericytes may not participate in sarcomatous development, (c) capillaries within the sarcomatous component are of non-gliomatous type, and (d) the histiocyte-like cells are capable of phagocytizing glial elements.

Histopathological features of recurrent pleomorphic xanthoastrocytomas: further corroboration of the glial nature of this neoplasm. A study of 3 cases

Pleomorphic xanthoastrocytoma (PXA), a tumor most often presenting superficially over the cerebral hemisphere of young subjects, has certain morphological similarities to fibrous histiocytoma (or fibrous xanthoma) of the meninges and brain, namely the occurrence of lipid-laden neoplastic cells and, frequently, a dense reticulin fiber network. The detection of glial fibrillary acidic (GFA) protein in the tumor cells helped to establish its astrocytic derivation, but it has been advanced that, in spite of this agreed observation, the tumor should still be regarded as a fibrous xanthoma of meningeal origin. Although many patients have a long symptom-free postoperative survival, local recurrences at varying intervals after surgery have been noted in some instances. Weldon-Linne et al. first reported that such a recurrence had the morphology of a small-cell glioblastoma. We are reporting three further examples of locally recurrent neoplasms in patients whose original meningocerebral tumors had the typical features of PXA; the recurrences (developing 7 months, 7 years and 15 years, respectively, after surgery) were small-cell glioblastomas. The rich reticulin network present in the initial tumor was mostly lost in the recurrences. This anaplastic evolution further confirms the astrocytic nature of the PXA.

Alteration of tumour cell arrangement related to connective tissue stroma in metastatic brain tumours. Histological and immunohistochemical studies of 68 autopsy cases

Tumour cell arrangements of a variety of 68 tumours metastatic to brain parenchyma and leptomeninges were compared histologically and immunohistochemically with those of the primary tumours in regard to their connective tissue stroma. In the brain parenchyma, more than 90% of 31 metastatic differentiated adenocarcinomas from various organs changed in cell arrangement from a tubular to a papillary pattern, in which tumour cells lined the increased perivascular connective tissue, rich in both type III collagen and fibronectin, the typical constituents of interstitial type extracellular matrices. Twelve (39%) and 3 of 31 cases were rearranged in a partially or completely tubular pattern respectively, within the metastatic nodules. Most of these neoplastic tubules were surrounded by diffusely proliferating connective tissue. Metastatic growth of carcinoma cells in the absence of supporting connective tissue in the nervous tissue was rare. A similar result was obtained for differentiated squamous cell carcinoma. In contrast, metastatic undifferentiated carcinoma and tumours with some neuro-ectodermal characteristics showed a sheet-like arrangement without pronounced connective tissue proliferation, similar to that of the primary tumours. In the leptomeninges, differentiated carcinoma cells were arranged in a tubular or a squamoid pattern and were frequently accompanied by marked stromal response. These results indicate that differentiated carcinomas require connective tissue stroma for metastatic growth, and that tumour cell arrangement in the brain varies depending upon the amount and distribution of proliferating connective tissue stroma. In undifferentiated carcinomas and tumours with neuro-ectodermal characteristics lacking stromal dependency, the tumor cell arrangement remains unchanged. The degree of stromal response to metastatic tumours in the brain parenchyma is related to the degree of epithelial differentiation.

Altered expression of collagen type VI in brain vessels of patients with chronic hypertension. A comparison with the distribution of collagen IV and procollagen III

The vascular extracellular matrix (ECM) plays an important role in the histopathology of cerebral microcirculation, but its characterization is still incomplete. For that reason we investigated paraffin-embedded and cryostat sections of intracerebral and meningeal vessels from eight normotensive and six hypertensive humans using monospecific affinity-purified polyclonal antibodies against human/monkey amino-terminal procollagen I + III peptide (P I P, P III P), collagen IV (7-S and NC1 domains), VI, and laminin (P 1 fragment) by applying peroxidase-antiperoxidase- and alkaline phosphatase-antialkaline phosphatase techniques. In normotensives, laminin and collagen IV were codistributed in the basal lamina of meningeal and intraparenchymal vessels. Collagen VI was only present in the adventitia of meningeal vessels and larger intraparenchymal arteries and veins, whereas it was absent from cortical vessels including capillaries. Intensive staining for collagen VI was observed in the choroid plexus, the superficial glia and sheath of cranial nerves. In hypertensives, the basement membrane constituents laminin and collagen IV appeared ubiquitously increased. Here, collagen VI was also deposited in the broadened vascular intima and media of larger arteries and in cortical vessels. In both groups collagen VI and P III P appeared to be codistributed. Our results indicate that significant qualitative change sin ECM of cerebral blood vessels are taking place during the development of hypertension, such as (1) an atypical deposition or an increase of collagen VI which by interconnecting collagen fibrils (I and III) might exert a stabilizing (sclerosing) function in the ECM, and (2) a thickening of vascular basement membranes caused by an accumulation of its major components laminin and collagen IV.