In-vitro analysis of the expression of TGFbeta -superfamily-members during chondrogenic differentiation of mesenchymal stem cells and chondrocytes during dedifferentiation in cell culture

Traditional surgical methods for the reconstruction of cartilage defects rely on the transplantation of autologous and allogenous tissues. The disadvantages of these techniques are the limited availability of suitable tissues and the donor site morbidity of transplants. In addition, in cultured chondrocytes, the dedifferentiation of cells seems unavoidable during multiplication. In this study, we investigated the expression of distinct markers during the dedifferentiation of human chondrocytes (HC) and human mesenchymal stem cells (MSC) in cell culture using microarray technique, immunohistochemistry and RT-PCR. Transforming growth factor beta (TGFbeta) is a multifunctional peptide that plays play a crucial role in inducing and maintaining chondrogenic differentiation. In dedifferentiating chondrocytes, the gene for TGFbeta1 was constantly expressed, while the gene for TGFbeta2 was never expressed. The genes for TGFalpha, TGFbeta4 and TGFbetai were activated with ongoing dedifferentiation. TGFbeta-receptor 3 was constantly expressed, while the genes for the TGFbeta-receptors 1 and 2 were never expressed. Immunohistochemical staining for TGFbeta beta 3 revealed upregulation in the course of dedifferentiation. The genes for LTBP1 and LTBP2 were activated with ongoing dedifferentiation, whereas the gene for LTBP3 was constantly expressed, and negative results were obtained for the gene for LTBP4. The genes for LTBP1 and LTBP2 were activated with ongoing dedifferentiation. During chondrogenic differentiation, the MSCs constantly expressed TGFbeta1, beta2, beta3 and beta4. LTBP1, LTBP2 and TGFbeta-R3 were downregulated. In conclusion, TGFbeta3, TGFbeta4, TGFbetai, LTBP1 and LTBP2 may assist the process of dedifferentiation, while TGFbeta1 and beta2 might not be involved in this process. Of the TGFbeta-receptors, only type 3 might be involved in dedifferentiation.

Angiogenesis in hereditary hemorrhagic telangiectasia: VEGF165 plasma concentration in correlation to the VEGF expression and microvessel density

Angiogenesis defines the physiologic process of capillary blood vessel formation. It is a multistep process, which is controlled by a large number of pro- and anti-angiogenic factors. Vascular endothelial growth factors (VEGF) are the best characterized pro-angiogenic factors, which play a key role in angiogenesis. Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant, multi-systemic disorder of angiogenesis, clinically characterized by severe and recurrent hemorrhages. We assume in HHT patients with increased VEGF plasma levels a high VEGF expression also correlates with the degree of microvesssel density (MVD). In 41 HHT patients and 47 healthy patients, the VEGF165 plasma concentration was determined by standard ELISA technique. Cryostat sections of 13 HHT patients were immunostained for VEGF and endothelial cells by an anti-vWF monoclonal antibody using a standard streptavidinbiotin complex procedure. The degree of vessel density was quantified by light microscopy (x200) within 'hot spot' areas of the HHT-tissue. All HHT cryostat sections showed a medium to strong staining for VEFG compared to healthy control tissue. The VEGF expression correlated with the VEGF165 plasma concentration and the mean MVD in HHT patients. HHT patients with medium VEGF staining revealed significantly lower VEGF165 plasma concentrations and a lower mean MVD (204+/-12 vessels/per microscopic field) than HHT patients with strong VEGF staining (327+/-76 vessels/per microscopic field). High VEGF expression in patients with HHT in correlation to their VEGF165 plasma levels and the microvessel density may support the theory that VEGF functions as an important regulator and key protein of angiogenesis, even in HHT.

Hepatocyte growth factor/scatter factor induces VEGF in human external auditory canal cholesteatoma cell culture

Human external auditory canal cholesteatoma (EACC) is not often seen in otolaryngology. Some authors have noted circulatory disorders of the local blood vessels as the etiologic factor for establishing EACC. Diminished oxygen supply results in the attempt to establish angiogenesis. Hepatocyte growth factor/scatter factor (HGF/SF) and vascular endothelial growth factor (VEGF) are the most important angiogenic factors in this process. In a recent study we described strong expression of VEGF and HGF in EACC. All EACC and normal AMS cell cultures were obtained from 5 patients undergoing surgery and used at passage 3. After 16 to 72 h of incubation with 20 ng/ml HGF/SF, the expression of the VEGF protein in the supernants of the HGF/SF-treated and untreated culture was analyzed. EACC-culture cells showed a stronger baseline expression of VEGF. After 72 h of incubation with 20 ng/ml HGF/SF of HGF/SF, the expression of VEGF in normal keratinocytes was 173.4 pg/ml. The expression level of VEGF in the EACC culture was 275.73 pg/ml. We observed a 2.5-fold induction of VEGF in EACC after 72 h, which started with 1.5-fold baseline VEGF concentrations of normal keratinocytes. Our analysis showed that, in the EACC culture, VEGF was elevated after treatment with HGF/SF. HGF/SF appears to activate cellular pathways inducing release of VEGF. After purification, no fibroblasts were present in our EACC culture so as to exclude possible paracrine effects by fibroblasts.

Expression von Zell-Zell-Adhäsionsproteinen im Gehörgangscholesteatom

BACKGROUND

External auditory canal cholesteatoma (EACC) is a rare entity in otolaryngology, which is histomorphologically identical with middle ear cholesteatoma. The cause of EACCt is, however, still not clear. The aim of this study was to describe the expression of beta-catenin, MMP-2, and MMP-9 in EACC matrix compared to the normal auditory meatal skin (AMS).

METHODS

Thirteen specimens were obtained during surgical procedure. EACC and AMS specimens were immunostained with antibodies for beta-catenin, MMP-2, and MMP-9.

RESULTS

Only the basal layers of the EACC specimens were positive for beta-catenin. The suprabasal layers showed diminished or negative immunostaining for beta-catenin. In all layers, AMS was homogeneously positive for beta-catenin. In contrast, the immunostaining for the gelatinases was equally increased in all layers of EACC, whereas AMS was weekly positive.

CONCLUSION

The reduced immunoreactivity for beta-catenin may have been present because of the lessened cell-cell adhesion in the suprabasal layers of EACC. The increased expression of the metalloproteinases might point at an increased lack of integrity of EACC matrix. Recent studies revealed a balance between disintegrating and stabilising factors in normal tissue, which is disturbed in inflamed and neoplastic tissue. In EACC matrix, an imbalance of these factors, represented by reduced beta-catenin and increased gelatinase expression, is possible. Increased desquamation, the accumulation of keratin debris, and loss of tissue-stability support our findings.

Expression of collagen and fiber-associated proteins in human septal cartilage during in vitro dedifferentiation

Chondrocytes surrounded by extracellular matrix are responsible for the maintenance of the cartilage as a functional entity. It is well accepted that chondrocytes cultivated for tissue engineering dedifferentiate in cell culture. We characterized the expression of different collagens and collagen related proteins in differentiated (primary) and cultured nasal chondrocytes by using microarray gene expression analysis and immunohistochemical staining. The genes for collagen subunits 1alpha1 (Col1alpha1) and 1alpha2 (Col1alpha2) were activated during a cell culture period of 5 and 20 days whereas Col2alpha1 could be detected both in differentiated and dedifferentiated chondrocytes. The long-term cell culture revealed a late activation of the Col3alpha1, Col4alpha1 and Col11alpha1 genes as well as biglycan, fibromodulin and lumican. In addition, short- and long-term cell culture resulted in down-regulation of Col9alpha1, Col9alpha2, Col9alpha3, Col10alpha1, Col18alpha1, ColQ and chondroadherin. The decorin gene showed up-regulation in short-term cell culture, but down-regulation in long-term culture. Immunohistochemical staining of the different cell populations confirmed the mRNA data for collagen type 1, 2, 3, 4, 9alpha2, 9alpha3, 18 and decorin. Because of their up-regulation in cultured chrondrocytes the collagen types 1, 3, 4 and 11 as well as biglycan, fibromodulin and lumican may be markers for dedifferentiation. The collagen types 9, 18 and Q as well as decorin and chondro-adherin revealed down-regulation and, presumably, represent markers for the differentiation of chondrocytes.

[Alcohol related diseases of the head and neck]

Chronic consumption of alcohol is an accepted social custom worldwide. In the upper aerodigestive tract, local morphologic, metabolic and functional alterations can be present due such consumption. Gastroesophageal reflux or alterations in sleep structure are typical examples of functional disorders. While alcohol was initially described as a risk enhancer only in smokers, a number of epidemiological studies have now shown that chronic alcohol consumption increases the risk of head and neck cancer independently of exposure to tobacco smoke. In addition, alcohol leads to an accumulation of pathologic microbes within the mucosa, leading to chronic infection. Susceptibility to carcinogens and cell proliferation in the mucosa are increased, resulting in genetic changes with the development of dysplasia, leucoplakia and carcinoma. Chronic alcohol consumption is correlated with an increased risk of cancer and increased mortality in a dose-dependent relationship. A number of biologically plausible mechanisms exist by which alcohol may cause cancer.

Targeting TGF-beta in human keratinocytes and its potential role in wound healing

The pathology of chronic dermal ulcers is characterized by excessive proteolytic activity which degrades extracellular matrix (required for cell migration) and growth factors and their receptors. The transforming growth factor-beta (TGF-beta) has been identified as an important component of wound healing. Recent developments in molecular therapy offer exciting prospects for the modulation of wound healing, specifically those targeting TGF-beta. We investigated expression of angiogenic bFGF and VEGF, and collagenases MMP-2 and MMP-9 in tissue samples from chronic dermal wounds by immunohistochemistry. The effect of TGF-beta targeting using antisense oligonucleotides on the expression of these factors was analysed by ELISA in human keratinocytes. Immunohistochemical investigation demonstrated a decreased expression of bFGF and VEGF protein, and an increased expression of MMP-2 and MMP-9 in tissue samples from chronic dermal wounds compared to normal human skin. Antisense TGF-beta oligonucleotide treatment down-regulated collagenase secretion activity and up-regulated VEGF secretion in vitro. Therefore, TGF-beta antisense oligonucleotide technology may be a potential therapeutic option for the inhibition of proteolytic tissue destruction, and stimulation of angiogenesis in chronic wounds. Improving basic knowledge and pharmaceutical intervention in this area ultimately may help clinicians to identify and proactively intervene in an effort to prevent normal wounds from becoming chronic.

Targeting chemotherapy-induced VEGF up-regulation by VEGF antisense oligonucleotides in HNSCC cell lines

BACKGROUND

Angiogenesis is increased in various human cancers, including head and neck squamous cell carcinoma (HNSCC), and correlates with tumour progression and metastasis. Vascular endothelial growth factor (VEGF) has been shown to be a key regulator of angiogenesis. Tumour treatment with anticancer agents might have an effect on the secretion of VEGF. Therefore, we determined whether certain chemotherapeutic agents stimulate VEGF secretion in HNSCC and whether VEGF antisense oligonucleotide treatment can modulate these effects in vitro.

MATERIALS AND METHODS

The effect of chemotherapeutic agents (Cisplatin, Carboplatin and 5-FU) on the production of VEGF was investigated on established human HNSCC cell lines at both mRNA and protein levels. By using a 21-mer VEGF antisense phosphorothioate oligonucleotide targeting the translation start site of human VEGF mRNA, we examined modulation of VEGF expression in cell line supernatants by capture ELISA.

RESULTS

The treatment of HNSCC cell lines with chemotherapeutic agents resulted in a significant induction of VEGF production. Carboplatin most prominently induced the release of VEGF from the tumour cells. VEGF antisense oligonucleotide treatment resulted in a significant reduction of chemotherapy-induced VEGF up-regulation compared to sense control.

CONCLUSION

Induction of VEGF secretion might contribute to the frequently observed drug resistance of HNSCC to chemotherapeutic agents. This molecular effect might be reduced by the use of VEGF antisense oligonucleotides in head and neck cancer therapy.

Dexpanthenol—Nasenspray vs. Nasensalbe

BACKGROUND

Recent technical developments in metered pump systems allow the production and use of preservative-free nasal products. The aim of the current study is to compare the tolerability of a preservative-free dexpanthenol (5%) nasal spray with that of the established dexpanthenol (5%) nasal ointment, also without preservatives. The main outcome measure was in vivo mucociliary clearance.

METHOD

Mucociliary clearance was assessed by saccharin migration time in 20 volunteers. Wash-out phases were 7 days and the spray or ointment was always applied 20 min before the saccharin test. The study was designed to test for non-inferiority.

RESULTS

Saccharin migration time was slightly longer after ointment administration, however, these were not significantly different to nasal spray. The saccharin migration time showed a significant correlation with the age of the volunteers. The upper confidence limit of dexpanthenol nasal spray was markedly less than that of the ointment. Therefore, dexpanthenol nasal spray is at least equal to if not better than dexpanthenol nasal ointment.

CONCLUSIONS

Due to its ease of administration, preservative-free dexpanthenol nasal spray offers a valuable therapeutic alternative.

Co-expression of different angiogenic factors in external auditory canal cholesteatoma

OBJECTIVE

Although external auditory canal cholesteatoma (EACC) was first described in 1850, its cause remains surprisingly unclear. Angiogenesis, the formation of new blood vessels, is essential to normal development and wound healing in adults. Abnormal regulation of angiogenesis has been implicated in the pathogenesis of several disorders. The aim of this study was to analyse angiogenesis regulator expression in EACC.

MATERIALS AND METHODS

Cryostat sections of 13 investigated EACC tissue samples and normal control tissue were immunostained for angiogenic hepatocyte growth factor (HGF)/scatter factor (SF), its c-Met receptor and vascular endothelial growth factor (VEGF) using a standard streptavidin-biotin complex procedure. Staining against von Willebrand factor (vWF) served as an endothelial marker. Statistical analysis was performed semiquantitatively.

RESULTS

The assayed angiogenic factors were all present in the EACC tissue, and partly overexpressed. vWF was detected in the apical layers of the matrix epithelium. Positive immunoreactivity for c-Met and VEGF was detectable in all layers of the EACC epithelium; however, adjacent tissue did not express c-Met and VEGE. HGF/SF was predominantly expressed in the adjacent perimatrix tissue and fibroblasts in particular were stained positive.

CONCLUSIONS

The presence of vWF in the apical part of the matrix depicted the attempt at angiogenesis in this part of the EACC. The detection of VEGF and c-Met in the epithelial part of the EACC implied that their origin may be epithelial, while HGF/SF may be secreted or stored in the adjacent mesenchymal EACC tissue. The angiogenic factors investigated seem to play an important role in establishing that EACC occurs by modulation of angiogenesis.

Abrogation of VEGF expression in human head and neck squamous cell carcinoma decreases angiogenic activity in vitro and in vivo

Angiogenesis is increased in various human cancers, including head and neck squamous cell carcinoma (HNSCC), and correlates with tumor progression and metastasis. Vascular endothelial growth factor (VEGF) has been shown to be a key regulator of angiogenesis. We determined whether VEGF antisense oligonucleotide treatment can decrease angiogenic activity of HNSCC cell lines in vitro and of HNSCC xenografts in vivo. Established human HNSCC cell lines were screened for VEGF expression at both mRNA and protein levels. By using a 21-mer antisense phosphorothioate oligonucleotide targeting the translation start site of human VEGF mRNA, we examined modulation of VEGF expression in cell line supernatants by capture ELISA, and in cell lysates by Western blotting. Human umbilica vein endothelial cells (HUVEC) were grown in conditioned medium produced from the treated tumor cells. Endothelial cell (EC) proliferation was determined by cell count and EC migration was measured using a modified Boyden chamber. Mice with HNSCC xenografts were treated with PBS, VEGF antisense or sense oligonucleotides (10 mg/kg; i.p. injection), respectively and tumor volumes were measured for 5 weeks. VEGF antisense oligonucleotide treatment resulted in a significant reduction of VEGF protein expression compared to sense control. Although the growth rate of the tumor cell lines was not affected, addition of conditioned medium from VEGF antisense-treated tumor cells resulted in decrease of endothelial cell proliferation and migration. VEGF antisense oligonucleotide treatment of HNSCC xenografts resulted in a significant tumor growth suppression. These results suggest that downmodulation of VEGF using antisense oligonucleotides may be a potential therapy for the inhibition of angiogenesis in HNSCC.

Tissue engineering with chondrocytes and function of the extracellular matrix (Review)

Tissue engineering represents a promising method for the construction of autologous chondrogenic grafts for reconstructive surgery. The destruction or malformation of organs such as nasal cartilage, pinna and trachea in otorhinology-head and neck surgery can be caused by both: primary disease or treatment modalities. A large part of modern medical practice is aimed to repair, replace, maintain or enhance the function of damaged or diseased tissues and organs. Replacement or repair is by either artificial implants or transplantation of tissues. Such interventions are hindered by factors such as rejection by the immune system, limited blood supply or morbidity of the donor site. Reconstruction of an injured face using plastic surgery is a prime example of when the limitations of materials, science and reconstructive techniques become apparent. This review aims to briefly outline the use of chondrocytes for tissue engineering with special regard to the function of the extracellular matrix for the signalling between the chondrocytes.