Biomedical subjects

M Polette

Publications and source records attributed to M Polette.

At least 37 records · Page 2Linked to original sources

PubMed1998

Association of fibroblastoid features with the invasive phenotype in human bronchial cancer cell lines.

The acquisition of a metastatic phenotype by epithelial cells implicates a series of changes altering their differentiation, their overall behavior and morphology. In the present study, we have examined the relationships between the cellular morphology, E-cadherin expression, matrix metalloproteinases expression and in vitro invasive properties in two human bronchial immortalized cell lines. The (16HBE14o-) cell line which did not show any invasive abilities in the Boyden chamber assay displayed a typical epithelial morphology in monolayer, expressed high levels of E-cadherin and synthesized neither MMP-2 and MT1-MMP nor vimentin. In contrast, the BZR cell line which was highly invasive displayed a more elongated phenotype in monolayer, did not produce E-cadherin but expressed vimentin, MMP-2 and MT1-MMP. Our data therefore suggest that the metastatic progression of broncho-pulmonary cancer cells results in a cellular dedifferentiation and the gain of some mesenchymal attributes (loss of E-cadherin and expression of vimentin) associated with enhanced degradative properties (expression of metalloproteinases).

Bronchial Neoplasms↗

PubMed1997

The elastase-induced expression of secretory leukocyte protease inhibitor is decreased in remodelled airway epithelium.

During airway inflammation, proteinases such as human leukocyte elastase are actively secreted. Secretory leukocyte protease inhibitor is a major serine proteinase inhibitor, secreted by bronchial, bronchiolar and lung epithelial cells. We recently identified secretory leukocyte protease inhibitor in human nasal epithelium, exclusively in remodelled areas of the surface epithelium. We now investigated the influence of remodelling and inflammation of the nasal tissue on the in vitro capacity of these cells to respond to human leukocyte elastase. Primary cultures of surface epithelial cells were established from various nasal polyp samples. At confluency, cell cultures were exposed to different human leukocyte elastase concentrations. The secretory leukocyte protease inhibitor immunocytolocalisation, expression and secretion were then investigated. Immunocytochemistry, showed a human leukocyte elastase dose-dependent increase of secretory leukocyte protease inhibitor containing cells and a basal extracellular localization of secretory leukocyte protease inhibitor after incubation with 100 microg/ml human leukocyte elastase. The relative amount of secretory leukocyte protease inhibitor mRNA transcripts increased with respect to the human leukocyte elastase concentration. Nevertheless, the potential stimulation of secretory leukocyte protease inhibitor secretion by human leukocyte elastase was lower in the more remodelled and inflamed tissue. Our results suggest that the contribution of the surface epithelial cells of poorly remodelled tissues to the protection against the deleterious effect of neutrophil proteinases is severely decreased in highly remodelled and inflamed tissues.

Cells, Cultured↗

PubMed1997

Expression of matrix metalloproteinases and their inhibitors in human bronchopulmonary carcinomas: quantificative and morphological analyses.

The expression of various matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in 88 primary bronchopulmonary cancers and in 13 neighbouring pulmonary parenchyma samples was quantified by Northern-blot analysis, and morphologically examined by in situ hybridization and immunohistochemistry in order to evaluate the involvement of MMPs in the pathophysiology of these carcinomas and to look for potential markers of aggressivity of lung tumours. Northern-blot analysis showed that the predominantly expressed MMPs in bronchopulmonary cancers were gelatinase A (66%), its activator MT1-MMP (membrane-type-1 matrix metalloproteinase) (56%) and stromelysin-3 (61%). MMP expression frequencies and mRNA levels increased progressively with malignant phenotype, lack of differentiation and TNM stage of the tumours, whereas TIMP expression decreased very early during tumour progression. Moreover, the principal MMPs were significantly co-expressed in primary tumours, suggesting their co-regulation. Morphological studies revealed the expression of MMPs and TIMPs essentially in stromal cells in close contact with tumour clusters. These results indicate that tumour progression in bronchopulmonary carcinomas implies a progressive disruption of the MMP/TIMP balance leading to an excess of several MMPs that act in concert in vivo. Furthermore, the fact that stromal cells are the principal source of MMPs emphasizes the close cooperation between host cells and cancer cells in tumour invasion.

Blotting, Northern↗

PubMed1997

Distribution of a1(IV) and a3(IV) chains of type IV collagen in lung tumours.

Tumour invasion is associated with strong remodelling of the extracellular matrix, including the basement membrane (BM). The major structural component of BMs is type IV collagen, which is composed of an association of three a chains. In this study, the distribution of the a1 and a3 chains in both normal and neoplastic lung tissues has been examined by immunohistochemistry, using specific monoclonal antibodies. In normal tissues, the a1(IV) chain was found in all BMs, whereas the a3(IV) chain was only found in alveolar BMs. In 36 lung tumours, the a1(IV) chain was detected in all cases, with irregular positivity around tumour clusters and in the stroma. It was noteworthy that this stromal distribution was particularly associated with the presence of cancer cells, whatever their invasive properties. In contrast, in 22 tumours out of 36, the a3(IV) chain was only found at the interface between invasive tumour clusters and stroma, with a linear and disrupted pattern. These data show a distinctive distribution of type IV collagen chains in lung tumours, with expression of a1(IV) chain and likely neosynthesis of the a3(IV) chain around some invasive tumour clusters. The results suggest the involvement of these BM components in the process of tumour invasion.

Antibodies, Monoclonal↗

PubMed1997

Expression of stromelysin-3 in the human placenta and placental bed.

Human placentation is mediated by fetal trophoblastic cells which penetrate into the decidualized uterine endometrium. Trophoblast invasion requires the precisely regulated secretion of specific proteinases able to degrade the endometrial basement membranes and extracellular matrix. To document further the involvement of these proteinases during human placentation, we evaluated in vivo the expression of stromelysin-3, a member of the metalloproteinase family, during the first and third trimesters of pregnancy, by means of immunohistochemistry, in situ hybridization and Northern blot analysis. Human extravillous trophoblasts invading the maternal decidua produced stromelysin-3 during both, the first and third trimesters of pregnancy, but to a lesser extent during the latter. In floating villi, stromelysin-3 expression was restricted to the syncytiotrophoblasts that line intervillous vascular spaces. In conclusion, stromelysin-3 is expressed by differentiated, non-proliferative villous and extravillous trophoblastic cells in early and late placental beds and villi, and its pattern of expression evolves during pregnancy. Our observations suggest that stromelysin-3 could play a role in human placentation.

Blotting, Northern↗

PubMed1997

Induction of membrane-type matrix metalloproteinase 1 (MT1-MMP) expression in human fibroblasts by breast adenocarcinoma cells.

Membrane-type matrix metalloproteinase 1 (MT1-MMP) has been recently described as an activator of proMMP-2 (MMP-2) which is involved in tumor invasion. We have shown by in situ hybridization that MT1-MMP is produced by stromal cells in close contact to preinvasive and invasive tumor cells of breast carcinomas. Of particular interest was the observation that some fibroblasts express this enzyme in focal areas in preinvasive lesions, suggesting that particular tumor cells may stimulate fibroblasts to produce MT1-MMP. We have therefore compared the ability of two different breast cancer cell lines, one non-invasive (MCF7) and one invasive (MDA-MB-231) to stimulate MT1-MMP production in human fibroblasts with consequent proMMP-2-activation. The MDA-MB-231 conditioned medium induced MT1-MMP mRNAs in human fibroblasts and a parallel activation of proMMP-2 whereas MCF7 conditioned medium did not have any effect. These results suggest the existence of soluble factor(s) secreted by invasive or some preinvasive breast tumor cells which stimulate fibroblasts to produce and activate MMPs, and emphasize the cooperation between cancer and stromal cells in tumor invasion.

Blotting, Northern↗

PubMed1997

Expression of c-ets-1 mRNA is associated with an invasive, EMT-derived phenotype in breast carcinoma cell lines.

We have previously observed in vitro that some stromal proteinases (MMP-2, MT1-MMP) were expressed or activated by invasive carcinoma cell lines exhibiting mesenchymal features, presumably acquired through an epithelial to mesenchymal transition (EMT). To examine the potential contribution of c-ets-1 to this phenotype, we have compared here the expression of c-ets-1 with invasiveness in vitro and expression of vimentin, E-cadherin, uPA, MMP-1 and MMP-3 in a panel of human breast cancer cell lines. Our results clearly demonstrate an association between c-ets-1 expression and the invasive, EMT-derived phenotype, which is typified by the expression of vimentin and the lack of E-cadherin. While absent from the two non-invasive, vimentin-negative cell lines, c-ets-1 was abundantly expressed in all the four vimentin-positive lines. However, we could not find a clear quantitative or qualitative relationship between the expression of c-ets-1 and the three proteinases known to be regulated by c-ets-1, except that when they were expressed, it was only in the invasive c-ets-1-positive lines. UPA mRNAs were found in three of the four vimentin-positive lines, MMP-1 in two of the four, and MMP-3 could not be detected in any of the cell lines. Intriguingly, MDA-MB-435 cells, which exhibit the highest metastatic potential of these cell lines in nude mice, expressed vimentin and c-ets-1, but lacked expression of these three proteinases, at least under the culture conditions employed. Taken together, our results show that c-ets-1 expression is associated with an invasive, EMT-derived phenotype in breast cancer cells, although it is apparently not sufficient to ensure the expression of uPA, MMP-1 or MMP-3, in the vimentin-positive cells. Such proteases regulation is undoubtedly qualified by the cellular context. This study therefore advances our understanding of the molecular regulation of invasiveness in EMT-associated carcinoma progression, and suggests that c-ets-1 may contribute to the invasive phenotype in carcinoma cells.

Breast Neoplasms↗

PubMed1997

MT1-MMP correlates with MMP-2 activation potential seen after epithelial to mesenchymal transition in human breast carcinoma cells.

We have previously reported that human breast carcinoma (HBC) cell lines expressing the mesenchymal intermediate filament protein vimentin (VIM+) are highly invasive in vitro, and highly metastatic in nude mice when compared to their VIM- counterparts. Since only VIM+ cell lines can be induced to activate matrix metalloproteinase-2 (MMP-2) upon stimulation with Concanavalin A (Con A), we have examined here membrane type 1 MMP (MT1-MMP), a cell surface activator of MMP-2. Northern analysis reveals baseline expression of MT1-MMP in five of the six VIM+ cell lines studied (MDA-MB-231, MDA-MB-435, BT-549, Hs578T, MCF-7(ADR)), each of which showed variable activation of exogenous MMP-2 after treatment with Con A. In contrast, the four VIM-, poorly invasive HBC cell lines studied (MCF-7, T47D, MDA-MB 468, ZR-75-1) lacked baseline MT1-MMP mRNA expression, and showed no induction of either MT1-MMP expression or MMP-2-activation with Con A. Such differential MT1-MMP expression was confirmed in vivo using in situ hybridization analysis of nude mouse tumor xenografts of representative cell lines. Western analysis of the MDA-MB-231 cells revealed baseline membrane expression of a 60 kDa species, which was strongly induced by Con A treatment along with a weaker band co-migrating with that from MT1-MMP-transfected COS-1 cells (63 kDa), presumably representing latent MT1-MMP. MT1-MMP immunofluorescence strongly decorated Con A-stimulated MDA-MB-231 cells in a manner consistent with membranous staining, but did not decorate the unstimulated MDA-MB-231 cells or MCF-7 cells under either condition. Collectively, the results suggest the constitutive production of active MT1-MMP which is unavailable for either MMP-2 activation or immuno-decoration until Con A treatment. Since VIM expression arises by virtue of the so-called epithelial to mesenchymal transition (EMT) in invasive embryonic epithelia, we propose that this represents a major metastasis mechanism in breast carcinomas. MT1-MMP on the surface of such 'fibroblastoid' carcinoma cells may mediate a paracrine loop for the utilization of stromally produced MMP-2, and contribute to the poorer survival associated with VIM+ breast carcinomas.

Animals↗

PubMed1997

Tumor collagenase stimulatory factor (TCSF) expression and localization in human lung and breast cancers.

Tumor cell-derived collagenase stimulatory factor (TCSF) stimulates in vitro the biosynthesis of various matrix metalloproteinases involved in tumor invasion, such as interstitial collagenase, gelatinase A, and stromelysin 1. The expression of TCSF mRNAs was studied in vivo, using in situ hybridization and Northern blotting analysis, in seven normal tissues and in 22 squamous cell carcinomas of the lung, and in seven benign proliferations and in 22 ductal carcinomas of the mammary gland. By in situ hybridization, TCSF mRNAs were detected in 40 of 44 carcinomas, in pre-invasive and invasive cancer cells of both lung and breast cancers. TCSF mRNAs and gelatinase A mRNAs were both visualized in the same areas in serial sections in breast cancers, and were expressed by different cells, tumor cells, and fibroblasts. The histological results were confirmed by Northern blot analysis, which showed a higher expression of TCSF mRNAs in cancers than in benign and normal tissues. These observations support the hypothesis that TCSF is an important factor in lung and breast tumor progression.

Antigens, CD↗

PubMed1997

Implication of collagen type I-induced membrane-type 1-matrix metalloproteinase expression and matrix metalloproteinase-2 activation in the metastatic progression of breast carcinoma.

We have previously demonstrated that fibroblasts and invasive human breast carcinoma (HBC) cells specifically activate matrix metalloproteinase-2 (MMP-2) when cultured on 3-dimensional gels of type I collagen but not a range of other substrates. We show here the constitutive expression of membrane-type 1 (MT1)-MMP in both fibroblasts, and invasive HBC cell lines, that have fibroblastic attributes presumably acquired through an epithelial-to-mesenchymal transition (EMT). Treatment with collagen type I increased the steady-state MT1-MMP mRNA levels in these cells but did not induce either MT1-MMP expression or MMP-2 activation in noninvasive breast carcinoma cell lines, which retain epithelial features. Basal MT3-MMP mRNA expression had a pattern similar to that of MT1-MMP but was not up-regulated by collagen. MT4-MMP mRNA was seen in both invasive and noninvasive HBC cell lines and was also not collagen-regulated, and MT2-MMP mRNA was not detected in any of the HBC cell lines tested. These data support a role for MT1-MMP in the collagen-induced MMP-2-activation seen in these cells. In situ hybridization analysis of archival breast cancer specimens revealed a close parallel in expression of both collagen type I and MT1-MMP mRNA in peritumoral fibroblasts, which was correlated with aggressiveness of the lesion. Relatively high levels of expression of both mRNA species were seen in fibroblasts close to invasive tumor nests and, although only focally, in certain areas close to preinvasive tumors. These foci may represent hot spots for local degradation and invasive progression. Collectively, these results implicate MT1-MMP in collagen-stimulated MMP-2 activation and suggest that this mechanism may be employed in vivo by both tumor-associated fibroblasts and EMT-derived carcinoma cells to facilitate increased invasion and/or metastasis.

Breast Neoplasms↗

PubMed1996

Cloning of choriocarcinoma cells shows that invasion correlates with expression and activation of gelatinase A.

Implantation and placental development are dependent upon trophoblast invasion of the endometrium. While the villous trophoblast does not display invasive behavior, the extravillous cytotrophoblast is highly invasive. By cloning BeWo choriocarcinoma cells, we have isolated two distinct clones that share similarities with villous and extravillous cytotrophoblasts. When cultured at the surface of a type I collagen gel, BeWo MC-1 cells were not invasive, whereas BeWo MC-2 cells rapidly invaded this matrix. When injected subcutaneously in nude mice, BeWo MC-1 cells developed a localized tumor and BeWo MC-2 cells developed larger tumors with micrometastases. Gelatinase A expression and minute amounts of gelatinase B were detected in the parental cell line and in both clones. However, the parental and the BeWo MC-2 cells secreted 5-to 10-fold more gelatinase A than the BeWo MC-1 cells. Laminin and matrigel stimulated the production of gelatinase A in BeWo MC-2 cells. Type I collagen promoted the conversion of the 72-kDa progelatinase A in an active enzyme only in parental BeWo and in BeWo MC-2 cells. These clones provide an interesting model for studying the complex mechanisms regulating implantation as well as the controlled invasiveness during implantation compared to tumor invasion.

Animals↗

PubMed1996

High level of MT-MMP expression is associated with invasiveness of cervical cancer cells.

MMP-2 (gelatinase A) has been associated with the invasive potential of many cancer cells both in vitro and in vivo. It is now becoming clear that the activation of this enzyme might be a key step in tumor invasion. This activation process has been shown to be a membrane-associated pathway inducible by various agents such as collagen type I, concanavalin A or TGF-beta, but its physiological regulation is still largely unresolved. MT-MMP was recently discovered and described as a potential gelatinase-A activator. In the present study, we investigated the expression of MT-MMP (membrane-type metalloproteinase) in cervical cancer cells both in vitro and in vivo. Comparing several in vitro-transformed cervical cell lines, previously shown to display different invasive potentials, our results showed that the ability of cells to overexpress MT-MMP mRNA following ConA induction correlated with their ability to activate gelatinase A and with a highly invasive behavior. Moreover, using immunohistochemistry and in situ hybridization, we found a higher level of MT-MMP expression in invasive cervical carcinoma and lymph node metastases compared to its expression in non-invasive CIN III lesions. Our in vivo observations also clearly demonstrated a cooperation between stromal and tumor cells for the production of MT-MMP. Taken together, our results clearly correlated high level MT-MMP expression with invasiveness, and thus suggested that MT-MMP might play a crucial role in cervical tumor invasion.

Base Sequence↗

PubMed1996

Vimentin expression in cervical carcinomas: association with invasive and migratory potential.

Vimentin is an intermediate filament protein normally expressed in mesenchymal cells, but evidence is accumulating in the literature which suggests that the aberrant expression of vimentin in epithelial cancer cells might be related to local invasiveness and metastatic potential. Vimentin expression has previously been associated with invasive properties in an in vitro model consisting of a set of HPV-33-transformed cervical keratinocyte cell lines. In the present study, in order to emphasize those in vitro findings, the expression of vimentin has been investigated in cervical neoplasms of different grades, using immunohistochemistry. A clear association is reported between vimentin expression and metastatic progression, since vimentin was detected in all invasive carcinomas and lymph node metastases, but not in CIN III lesions. These in vivo results are compared with present and previous data obtained in vitro on cervical keratinocyte cell lines, where vimentin expression also correlated with in vitro invasiveness.

Animals↗

PubMed1996

Gelatinase B is involved in the in vitro wound repair of human respiratory epithelium.

Following epithelial injury, extracellular matrix undergoes imposing remodelings. We examined the contribution of matrix metalloproteinases, gelatinases A and B, in an in vitro wound repair model of human respiratory epithelium. Confluent human surface respiratory epithelial (HSRE) cells cultured from dissociated surface cells of human nasal polyps were chemically injured. Over the next 3 to 5 days, cells migrated onto the injured area to repair the circular wound. Repair kinetics of these wounds was monitored until wound closure occurred. Gelatinolytic activities were analysed in culture supernates and in cell protein extracts derived from repairing migratory and non repairing stationary cells. Small amounts of gelatinase A were expressed by HSRE cells, and variations of this gelatinase remained very weak for the time of the wound repair. In contrast, gelatinase B was upregulated during the wound repair process, with a maximum peak observed at wound closure. A marked gelatinase B activation occurred only in cells involved in the repair process. Gelatinase B was localized in some migratory basal cells, recognized by an anti-cytokeratin 14 antibody and located around the wound. We could not detect any gelatinase A in repairing or in stationary HSRE cells. Addition of the 6-6B monoclonal antibody, known to inhibit gelatinase B activation, to the culture medium during the repair process resulted in a dose-dependent decrease of the wound repair speed. These results suggest that gelatinase B, produced by epithelial cells, actively contributes to the wound repair process of the respiratory epithelium.

Adult↗

PubMed1996

MT-MMP expression and localisation in human lung and breast cancers.

Thirteen primary pulmonary squamous cell carcinomas, 4 specimens of normal lung from around tumours, 4 benign proliferations of the mammary gland and 16 breast carcinomas were analysed by in situ hybridisation. Northern blot and immunohistochemistry for the expression of a recently described metalloproteinase (MMP), the MT-MMP (membrane-type matrix metalloproteinase). This MT-MMP can activate gelatinase A, involved in the degradation of basement membranes. In situ hybridisation revealed MT-MMP transcripts distributed in both tumour and stromal cells in squamous cell lung cancers, whereas these mRNAs were principally detected in stromal cells in close contact to tumour clusters in breast carcinomas and in lung adenocarcinomas. Northern blot analysis showed a parallel expression of MT-MMP and gelatinase A transcripts in both lung and breast cancers. Immunohistochemistry displayed a more extensive distribution of MT-MMP in pulmonary and mammary carcinomas with numerous labelled preinvasive and infiltrating cancer cells and stromal cells near the tumour cells. The large degree of expression of MT-MMP in these cancers indicates a potential role of this enzyme in tumour progression. The finding of MT-MMP transcripts in stromal cells in the vicinity of lung and breast tumour cells emphasises the cooperation between these cells and cancer cells for the expression of MT-MMP and in tumour invasion in vivo.

Breast Neoplasms↗

PubMed1996

Membrane-type matrix metalloproteinase-1 expression at the site of human placentation.

Human trophoblast implantation is a highly regulated process of invasion that requires action of proteolytic enzymes to degrade extracellular matrix components of the endometrium. Among these enzymes, matrix metalloproteinases (MMPs) seem to be particularly important in this degradative process. We previously showed that gelatinase A is extensively expressed in vivo in the human placenta. A new MMP, MT-MMP-1 (membrane-type matrix metalloproteinase-1), which is thought to activate progelatinase A, has recently been described. In this study, we examined the expression of MT-MMP-1, by immunohistochemistry and in situ hybridization, in human placental bed biopsies taken during the first trimester of gestation. Human first trimester intermediate trophoblasts synthesized MT-MMP-1 mRNAs and the protein. The MT-MMP-1 pattern of distribution in placental beds was similar to that of gelatinase A, suggesting a pivotal role for MT-MMP-1 in placentation, perhaps by activating progelatinase A.

Blotting, Northern↗

PubMed1996

Wound repair-induced expression of a stromelysins is associated with the acquisition of a mesenchymal phenotype in human respiratory epithelial cells.

Wound repair involves many processes including cell migration, provisional matrix deposition, and remodeling. All of these processes are likely to be affected by matrix-modifying enzymes. Members of the matrix metalloproteinases family are physiologic mediators of the extracellular matrix degradation. Within this matrix metalloproteinases family, stromelysins can degrade many components of the extracellular matrix. We therefore tested the hypothesis that stromelysins could be produced by human surface respiratory epithelial (HSRE) cells repairing a wound. Experimental wounds were created in vitro in HSRE cell cultures and in situ in human bronchial mucosa maintained in organ culture. Stromelysin production was measured by casein-gel zymography in cellular protein extracts derived from repairing migratory and nonrepairing stationary cells of wounded HSRE cell cultures. Stromelysin-producing cells present in cell and tissue cultures were localized and characterized using immunofluorescence techniques. Zymographic and immunofluorescence techniques showed that stromelysins were produced exclusively by the migratory HSRE cells. Zymogram analysis showed that stromelysins were overexpressed and overactivated during the wound repair process, with the maximal production observed at wound closure. Using an anti-cytokeratin 14 antibody, we identified stromelysin-3-producing cells as basal epithelial cells. Moreover, most stromelysin-3-producing cells expressed the mesenchymal marker vimentin. Similar to stromelysins localization, vimentin-positive HSRE cells were exclusively located in the wounded area, and they were also positive to cytokeratin 14. In conclusion, stromelysins are suggested to be involved in HSRE cell migration and extracellular matrix remodeling during wound repair. Furthermore, stromelysin production by repairing HSRE cells is linked to the acquisition of a mesenchymal phenotype. HSRE cell migration may then be associated with the shift from an epithelial to a mesenchymal phenotype.

Bronchi↗

PubMed1995

Identification of antileucoprotease in remodelled human adult nasal surface epithelium.

Antileucoprotease (ALP) is generally considered as a specific marker for glandular serous cells, and plays a major role in the defence of the respiratory tract against proteolytic damage. Nevertheless, several studies have identified ALP in bronchial and bronchiolar surface epithelial cells, and also an increased number of ALP-containing cells in bronchiolar tissue during the development of pulmonary diseases. In order to define more clearly whether the surface epithelium might be involved in the defence of the respiratory mucosa, we have investigated the expression of ALP by cells of the nasal surface epithelium. Indirect immunocytochemistry and in situ hybridization for ALP were performed on human nasal polyp sections. The height of the surface epithelium, its morphology, and the degree of local inflammation were assessed in parallel. Surface epithelium morphology was highly heterogeneous. ALP-containing cells were identified, but only in remodelled areas of the surface epithelium (foldings, basal cell and/or mucous cell hyperplasia), with no association to the degree of inflammation. These results demonstrate that the surface epithelial cells of the human adult nasal mucosa can express ALP in remodelled surface epithelium, and may be actively involved in the biochemical defence of the airways.

Epithelium↗