Current status of genetic modulation of growth factors in wound repair

Growth factors are members of a large functional group of polypeptide regulatory molecules secreted by different cells. They are important players in orchestrating all stages of wound healing exerting their influence through autocrine and paracrine fashions within sites of injury and repair. They are mitogen, chemotactic, they regulate cell-cell interactions and influence synthesis and composition of extracellular matrix components. The use of growth factors to stimulate wound healing is a promising therapeutic approach to repair chronic tissue defects. The delivery of genetic material offers an attractive treatment modality to produce an appropriate amount of growth factor proteins within the wound site. Gene therapy might become a significant treatment modality for those wound healing pathologies refractory to other wound management approaches. This review discusses several methods of growth factor gene transfer into wound tissue.

In vitro analysis of integrin expression during chondrogenic differentiation of mesenchymal stem cells and chondrocytes upon dedifferentiation in cell culture

Tissue engineering represents a promising method for generating chondrogenic grafts for reconstructive surgery. In cultured chondrocytes, the dedifferentiation of cells seems unavoidable for multiplication. Stem cells, however, displaying unlimited self-renewal and the capacity to differentiate towards chondrocytes, might be usable after further characterization. As the interactions between the extracellular matrix and the cellular compartment can alter the cellular behaviour, we investigated the expression of integrins using microarray analysis during chondrogenic differentiation of human mesenchymal stem cells (MSC) in comparison with de-differentiating human chondrocytes (HC) harvested during septoplasty. During chondrogenic differentiation of MSC, the fibronectin-receptor (Integrin beta1alpha5), fibronectin and the GPIIb/IIIa-receptor were downregulated. The components of the vitronectin-receptor (Integrin alphavbeta3) and CD47 were constantly expressed and ILK was downregulated. Vitronectin and osteopontin were not expressed by the cells. In HC, Integrin beta1alpha5 in conjunction with the ligand fibronectin were upregulated during dedifferentiation, Integrin alphavbeta3 as well as the GBIIb/IIIa-receptor were activated on day 21 but neither vitronectin nor osteopontin were expressed by the cells. The integrins, beta2, beta4, beta6, beta8 and alpha2, alpha4, alpha6, alpha7, alpha11, were not expressed at any time. ILK, CD47, and ICAP were activated with ongoing dedifferentiation. In conclusion, a candidate for signal-transmission is the fibronectin receptor (integrin alpha5beta1) in conjunction with its ligand fibronectin. Other receptors, e.g. for vitronectin and osteopontin (alphavbeta3), or their ligands do not seem to be involved in signal transmission for dedifferentiation. The GPIIb/IIIa-receptor might assist the process of dedifferentiation. Intracellularly, ILK, ICAP1 and CD47 might be involved in the transduction of integrin-dependent signals.

Targeting TGF-beta1 increases hepatocyte growth factor (HGF/SF) levels in external auditory canal cholesteatoma (EACC) epithelial cell culture

OBJECTIVE

The transforming growth factor (TGF)-beta 1 is known to have pro- and anti-angiogenic actions. Hepatocyte growth factor/scatter factor (HGF/SF) antagonizes TGF-beta1 by stabilizing SMAD transcriptional co-repressor TGIF. HGF/SF is a multifunctional polypeptide with morphogenic, motogenic, angiogenic, and proliferative capabilities. We assume HGF to be a pivotal factor during the pathogenesis of the external auditory canal cholesteatoma (EACC). In this study, we investigate the effect of antisense targeting TGF-beta1 on HGF/SF levels in the epithelial EACC-culture.

MATERIALS

For 48 h, epithelial EACC cell culture was incubated with 3 and 6 mumol antisense targeting TGF-beta1, respectively. Levels of HGF/SF were determined and normalized to cellular protein. Untreated EACC cell culture and scrambled TGF-beta1-antisense served as control. In the second experiment, EACC cells were incubated with rh TGF-beta1 (2 and 4 ng/ml) for 48 h and HGF/SF was determined.

RESULTS

After incubation with 3 mumol TGF-beta1-antisense, the average level of HGF/SF was measured at 43.68 pg/ml. Incubation with 6 micromol TGF-beta1-antisense showed 64.95 pg/ml. In untreated EACC (control), the average level of HGF/SF after 48 was 34.55 pg/ml. Incubation with scrambled TGF-beta1 oligonucleotide showed an average HGF/SF level of 34.41 (3 micromol) and 35.66 (6 micromol), respectively. The difference between the scrambled antisense and the targeting antisense TGF-beta1 was significant (p<0.05). After incubation with 2 ng/ml TGF-beta1, the HGF/SF levels were at 22.16 pg/ml. TGF-beta1, 4 ng/ml, resulted in 15.33 pg/ml of HGF/SF. The difference of the levels of HGF/SF after incubation with exogenous TGF-beta1 was significant (p<0.05).

CONCLUSION

In this study, levels of HGF/SF increased in the epithelial EACC cell culture after incubation with 3 and 6 mumol antisense TGF-beta1 oligonucleotides depending on the concentration of the antisense. In reverse, TGF-beta1 acted as inhibiting cytokine on HGF/SF levels. In conclusion, TGF-beta1 may be a useful therapeutic agent for managing EACC.

Plastische Deckung von Weichteildefekten im Gesicht

The difficulties in facial reconstruction derive from the unique character of the face and the availability of local matching tissues. Facial reconstructive surgery must aim at a functionally and aesthetically rehabilitated patient. The performance of facial plastic surgery requires an understanding and the application of many important principles. The aim of this paper is to review the critical factors to be considered in the management of surgical wounds by second-intention healing, primary closure, skin grafting, and repair with local or distant free flaps. The key concepts useful in flap choice and implementation are discussed. In addition, an overview of new developments in tissue engineering and gene therapy as they relate to facial plastic surgery is provided.

Dual FISH analysis of benign and malignant tumors of the salivary glands and paranasal sinuses

To date, the underlying genomic changes in benign and malignant tumors of salivary-gland and paranasal-sinus origin are poorly understood. This is due in part to the low incidence of these tumors and the enormous histological variety of tumors within this head and neck region. We examined 58 of these tumors (14 adenoid cystic carcinomas, 9 adenocarcinomas, 5 cylindrical carcinomas, 11 pleomorphic adenomas, and 19 inverted papillomas) by dual fluorescence in situ hybridization (FISH) with centromere-specific probes on six chromosomes (3, 7, 9, 11, 17, and 18) for numerical changes. In adenoid cystic carcinomas, monosomy of chromosome 17 and polysomy of chromosomes 3, 9 and 11 were most frequently encountered. In adenocarcinomas, monosomy of chromosome 17 and polysomy of chromosomes 7 and 11 were most frequent. In cylindrical cell carcinomas, polysomy of chromosomes 7, 9, 11 and 17 was present in the majority of tumors. Disomy is rare, even in benign tumors. Polysomy is more frequent in malignant tumors than in benign. Tetrasomy is found almost only in malignant tumors. In summary, the occurrence of polysomy might reflect a step towards malignancy in tumors of the salivary glands and paranasal mucosa. Polysomy of chromosome 11 could be defined as typical for all investigated histological types of malignant tumor in this region of the head and neck.

Estriol induced squamous metaplasia on the nasal mucosa in patients with hereditary hemorrhagic telangiectasia

BACKGROUND

The aim of this study was to evaluate by light and electron microscopy the effect of topical estriol on the nasal mucosa in patients with hereditary hemorrhagic telangiectasia (HHT).

METHODS

Twelve patients were instructed to apply twice daily 0.1% estriol as a nose ointment over a period of 12 months. Written consent was obtained from each patient, allowing biopsy specimens of the nasal mucosa to be taken prior to and 3, 6 and 12 months after estriol application.

RESULTS

Metaplastic change of the nasal mucosa was observed 6 months after topical estriol application. The former ciliated columnar epithelium changed into a keratinizing squamous epithelium. The effect was reversible after discontinuation of estriol application.

CONCLUSIONS

For the first time, we could outline the effect of topical estriol on the nasal mucosa. These histomorphological findings, and the fact that estriol is a low-potency metabolite of estradiol, make estriol a valuable agent in the treatment of HHT patients.

Human chondrocytes differentially express matrix modulators during in vitro expansion for tissue engineering

Cartilage tissue engineering plays an important role in the generation of grafts for reconstructive surgery. In cultured chondrocytes, the dedifferentiation of cells seems unavoidable for multiplication. Dedifferentiated cells produce matrix of less quality, and the molecular basis is still not well understood. Therefore, the aim of our study was to investigate the expression of matrix modulators in human chondrocytes during expansion. Human chondrocytes were isolated from septal cartilage (n=32) and held in primary cell culture. Cells were harvested after 1, 6 and 21 days. The differentiation of cells using light microscopy, the expression patterns of various proteins (MMPs, BMPs, and TIMPs) using immunohistochemistry, and the expression of distinct genes using microarray technique, were investigated. The chondrocytes showed strong in vitro proliferation. After 6 and 21 days, BMP-5 and -8 were up-regulated, BMP-2 was down-regulated and BMP-6 was inactivated. Other BMPs were not expressed. The expression of MMP-2, -3 and -13 was up-regulated from day 1 to 21, and MMP-12 and -20 were down-regulated. Other MMPs were not expressed. TIMP-1 was up-regulated and TIMP-3 was down-regulated during expansion. Differential expression of matrix modulators might influence the matrix composition of engineered cartilage. Improving the basic knowledge in this area may ultimately help clinicians to identify and proactively intervene in an attempt to prevent bioartificial cartilage from losing stability.

Serum levels of interleukin-6 in patients with primary head and neck squamous cell carcinoma

Interleukin (IL)-6 plays a central role as a differentiation and growth factor of tumor cells. IL-6 has been identified in a wide variety of malignancies, including head and neck squamous cell carcinomas (HNSCC). The aim of this study was to investigate the association between the serum levels of IL-6 in HNSCC patients and the biological characteristics of the tumor as well as the clinicopathological status of the patients. The circulating level of IL-6 in sera from patients with various HNSCC (n = 90) as well as from healthy normal controls (n = 39) was investigated. Serum IL-6 concentrations were determined as serum immunoreactivity using a quantitative sandwich enzyme immunoassay technique. For statistical analysis, the Kruskal-Wallis test was performed. The majority of the patients with HNSCC were found to have high serum IL-6 concentrations. The IL-6 levels in the sera of patients with cancer ranged from below the detection limit to 312.8 pg/ml (mean, 19.5 pg/ml). In contrast, the IL-6 serum levels in 39 healthy individuals ranged from below the detection limit to 52.2 pg/ml (mean, 6.0 pg/ml), with the concentration being significantly higher in HNSCC patients (p < 0.001). Furthermore, the correlation of the IL-6 serum concentration with tumor stage was significant (p = 0.04). Accordingly, there was a significant difference of IL-6 serum concentration of tumors with positive and negative lymph nodes (p = 0.045), with concentration being significantly higher in lymph node-positive tumors. Our data on elevated IL-6 serum levels in the majority of HNSCC cancer patients and its correlation with tumor stage and lymph node status suggest that serum IL-6 reflects the proliferative activity of the tumor in patients with head and neck cancer. IL-6 serum determinations might serve as a biological marker and help to identify advanced head and neck tumors.

Patients with hereditary hemorrhagic telangiectasia have increased plasma levels of vascular endothelial growth factor and transforming growth factor-beta1 as well as high ALK1 tissue expression

BACKGROUND AND OBJECTIVES

Hereditary hemorrhagic telangiectasia (HHT), an inherited vascular dysplasia, is caused by mutations in endoglin or activin receptor-like kinase (ALK)-1. Haploinsufficiency for these genes is thought to result in an imbalanced angiogenic activity. The aim of this study was to evaluate the plasma levels and the expression profiles of angiogenic and angiogenesis-related factors in the context of HHT.

DESIGN AND METHODS

Vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-beta1 plasma concentrations were determined in 31 HHT patients and 40 healthy controls by ELISA. VEGF and TGF-beta1 plasma concentrations were correlated with the patients' clinicopathological features. Tissue expression of angiogenic and angiogenesis related proteins was determined by immunostaining on nasal cryostat sections from 13 HHT patients and 5 healthy controls.

RESULTS

Of the 31 patients, 29 had statistically significantly raised plasma concentrations of VEGF and TGF-beta1 but there was no correlation with specific clinicopathological features. Increased VEGF, TGF-beta1 and ALK1 immunostaining was seen in all 13 investigated patients. beta-smooth muscle actinin immunostaining was increased in 12 patients. Increased endoglin immunostaining was seen in only 9 patients.

INTERPRETATION AND CONCLUSIONS

This study provides evidence of the role of VEGF and TGF-beta1 in the pathogenesis of HHT. Plasma concentrations of these two factors may serve as further diagnostic criteria for HHT. For the first time, we report increased TGF-beta1 plasma concentrations and increased TGF-beta1 and ALK1 tissue expression in HHT, which appear not to be specifically associated with either endoglin or ALK1 mutations. The data suggest that HHT is an angiogenic disorder characterized by an over-expression of VEGF, TGF-beta1 and ALK1.

In vitro analysis of matrix proteins and growth factors in dedifferentiating human chondrocytes for tissue-engineered cartilage

CONCLUSIONS

With ongoing culture and dedifferentiation of chondrocytes, significant changes in the expression patterns of various collagens and the insulin-like growth factor (IGF) receptor were detected. The latter could play an important role in the differentiation of human chondrocytes.

OBJECTIVE

Tissue engineering represents a promising method for the construction of autologous chondrogenic grafts for reconstructive surgery. So far, little is known about the expression of markers for cell proliferation and differentiation in cultured chondrocytes.

MATERIAL AND METHODS

Human chondrocytes were isolated from septal cartilage (n=5) and held in primary cell culture. Cells were harvested after 24 h and 6 days. Proliferation was analyzed using an Alamar Blue assay. The differentiation of the cells was investigated using bright field microscopy, the expression patterns of various proteins using immunohistochemistry and the expression of distinct genes using a microarray technique.

RESULTS

The chondrocytes showed strong proliferation (Day 0: 16.7+/-0.7 fluorescent units; Day 5: 52.4+/-2.2 fluorescent units) from the third day of cell culture in medium without growth factors. From this point onwards, a dedifferentiation of the chondrocytes could be observed. In cell culture, the chondrocytes expressed collagen 1 and 10 without expression of collagen 3. After 6 days of cell culture, they expressed collagen 2. The chondrocytes showed constant low expression of the fibroblast growth factor-2 receptor, but constant high expression of vascular endothelial growth factor, matrix metalloproteinase (MMP)2 and MMP9. The cells never expressed the epidermal growth factor receptor. The proportion of IGF receptor-expressing cells diminished significantly during cell culture.

Tissue engineering with adult stem cells in reconstructive surgery (review)

Tissue engineering is a multidisciplinary field combining biology and engineering along with clinical application to design, manufacture, modify, grow and maintain living tissue. This field has enjoyed tremendous growth in the past 10 years fueled by its potential role in regenerating new tissues and naturally healing injured or diseased organs. Many approaches to tissue engineering have been explored, including ex vivo de novo construction of tissues and strategies of in vivo induction of tissue regeneration. Interventions are hindered by factors such as rejection by the immune system, limited blood supply or morbidity of the donor site. Regardless of the approach, most researchers and clinicians agree that any successful tissue engineering construct will derive from a single unit, the cell. Because the engineering of tissue necessitates a sufficient number of tissue-specific cells with minimal donor site morbidity, a great deal of scientific effort has been directed towards stem cell research and the use of stem cells as a source of cells for new tissues. This review aims at outlining the role of stem cells in tissue engineering, focusing on the use of adult-derived stem cells as applied to the research and practice of plastic surgery.

Differential modulation of integrin expression in chondrocytes during expansion for tissue engineering

Cartilage tissue engineering has an important role to play in the generation of graft material for reconstructive surgery. In cultured chondrocytes, the dedifferentiation of cells seems unavoidable for multiplication. Dedifferentiated cells produce matrix of less quality. Normal cartilage is composed of chondrocytes, which are embedded within an extracellular matrix (ECM). The ECM plays a key role in controlling cellular characteristics and contains the integrins as a large family of heterodimeric cell adhesion receptors involved in cell-cell and cell-matrix interactions. In this study, the characteristic changes of integrin expression and expression of matrix proteins during the course of dedifferentiation of chondrocytes in cell culture for 1, 6 and 21 days, analyzed at the mRNA level by microarray analysis and at the protein level by immunohistochemistry, are described. The components of the fibronectin receptor, integrin beta1,alpha5, in conjunction with the ligand fibronectin, were up-regulated during dedifferentiation. Integrin beta3 was expressed in the grey area. The components of the vitronectin-receptor, integrin alpha2b, alpha v, as well as integrin beta5, were activated on day 21, but neither vitronectin nor osteopontin were expressed by the cells. With ongoing dedifferentiation, activation of the GPIIb/GPIIIa receptor was found. The integrins beta2, beta4, beta6, beta8 and alpha2, alpha4, alpha6, alpha7 and alpha11 were never expressed. ILK, CD47 and ICAP1, as components of the intracellular signalling cascade of several integrins, were activated with ongoing dedifferentiation. In conclusion, a candidate for signal transmission during dedifferentiation is the fibronectin receptor (integrin alpha5beta1) in conjunction with its ligand fibronectin. Other receptors, e.g. for vitronectin and osteopontin (alphaVbeta3) or laminin (alpha6beta1) or their ligands, do not seem to be involved in signal transmission for dedifferentiation. In addition, the GPIIb/IIIa-receptor seems to assist the process of dedifferentiation. Intracellularly, ILK, ICAP1 and CD47 might assist the transduction of the integrin-dependent signals.

Up-regulation of beta-catenin in external auditory canal cholesteatoma

The external auditory canal cholesteatoma (EACC) is a rare disease with hyperproliferation and destructive growth in the adjacent structures. Down-regulation of beta-catenin (key component of the zonula adherens) is a pivotal factor for loose tissue integrity and invasiveness. Transforming growth factor beta1 (TGF-beta1) was reported to decrease beta-catenin in mammary epithelium. We investigated the abrogation of TGF-beta1 and beta-catenin expression in EACC culture cells. Cultured EACC-specimens were incubated with 6 micromol TGF-beta1 antisense. After 48 h, expression of beta-catenin was determined by means of immunohistochemistry. The cells showed an increased mural reactivity to beta-catenin, and intracellular reactivity was unchanged. The untreated cells showed a loss of beta-catenin expression at the membranes. The predominant membranous location after treatment with TGF-beta1 antisense suggests increased tendency of the cells for tissue formation and strong cell-cell adhesion rather than migratory and invasive character, and thus TGF-beta1 antisense application is a useful therapeutical strategy.

Plasma level and tissue expression of angiogenic factors in patients with hereditary hemorrhagic telangiectasia

The value of angiogenic factors interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF) was determined in patients with hereditary hemorrhagic telangiectasia (HHT) to evaluate their role in HHT pathogenesis. IL-8 and VEGF were measured in plasma of 41 HHT patients and healthy controls by ELISA technique. In both groups, the IL-8 and VEGF tissue expression in cryostat sections of the nasal mucosa were then compared. VEGF plasma levels were significantly increased in HHT patients compared to healthy controls. In contrast, the IL-8 plasma levels in both groups did not show any significant difference. Compared to healthy controls, HHT tissue samples showed a weak IL-8 staining, whereas the VEGF staining was very strong. The plasma levels of VEGF and IL-8 could not be correlated to the patients' clinicopathological findings. Additionally to the angiogenic pro-inflammatory cytokine IL-8, the angiogenic factor VEGF seems to play a major role in HHT pathogenesis.

Regulation of Apoptosis in External Auditory Canal Cholesteatoma by Hepatocyte Growth Factor/Scatter Factor

OBJECTIVES

External auditory canal cholesteatomas (EACC) are characterized by focal invasion of squamous cell epithelium and accumulation of keratin debris in the apical part of the matrix. Apoptosis appears to be important in understanding the pathogenesis of EACC. Here the possible regulatory effect of the apoptosis mediated by hepatocyte growth factor (HGF)/scatter factor (SF)-c-Met-Fas in EACC is discussed.

METHODS

We examined 17 EACC specimens for immunohistochemical expression of HGF/SF, c-Met, caspase 3 and Fas. The staining reaction was evaluated semiquantitatively.

RESULTS

HGF/SF was detected in mesenchymal tissue below the EACC epithelium. c-Met was expressed throughout the epithelium. Fas and caspase 3 were detected at increasing levels towards the apical layers of the EACC matrix.

CONCLUSIONS

High levels of HGF/SF result in binding of HGF/SF to c-Met, releasing Fas to aggregate and bind to its death-inducing signaling complex. The result is apoptosis, marked by formation of dead squamous cells and sequestered keratin debris on the apical side of the cholesteatoma.

Immunohistochemical analysis of radiation-induced non-healing dermal wounds of the head and neck

Persistent, poorly healing wounds are a significant clinical problem in patients who have had previous irradiation. The pathology of chronic dermal ulcers is characterised by excessive proteolytic activity which degrades the extracellular matrix (required for cell migration) and growth factors and their receptors. Interestingly, the molecular basis of radiation-induced dermal wounds is poorly understood. The aim of this study was to investigate, by immunohistochemistry, the expression of the endothelial marker vWF, of angiogenic bFGF, VEGF and IL-8, of collagenases MMP-2 and MMP-9 and their inhibitors TIMP-1 and TIMP-2, in tissue samples from radiation-induced chronic dermal wounds and healthy control skin. Performing immunohistochemical detection of microvessels, an equivalent density of microvessels was observed within tissue samples from normal healthy skin and from radiation-induced non-healing cutaneous wounds. Investigation of angiogenic bFGF and VEGF demonstrated a decreased expression of both factors in the radiation-induced dermal wounds. The expression of angiogenic IL-8 was weak in both the healthy skin samples and the radiation-induced wounds. In addition, an increased expression of collagenases MMP-2 and MMP-9 protein within the radiation-induced wounds was demonstrated. While the expression of TIMP-1 showed no difference of expression between normal control skin and tissue samples from radiation-induced wounds, TIMP-2 expression was slightly increased compared to healthy controls. Our data suggest that radiation-induced dermal injuries often fail to heal because of decreased angiogenesis and persistently high concentrations of MMPs with an imbalance of their tissue inhibitors. The basic mechanisms of wound healing in radiation-induced dermal wounds at the molecular level need to be understood further for the development of innovative treatment strategies.

TGF-beta antisense oligonucleotides reduce mRNA expression of matrix metalloproteinases in cultured wound-healing-related cells

The pathology of chronic dermal ulcers is characterized by excessive proteolytic activity which degrades extracellular matrix. 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 the effect of TGF-beta antisense oligonucleotides on the mRNA expression of matrix metalloproteinases in cultured human keratinocytes, fibroblasts and endothelial cells using multiplex RT-PCR. The treatment of keratinocytes and fibroblasts with TGF-beta antisense oligonucleotides resulted in a significant decrease of expression of mRNA of MMP-1 and MMP-9 compared to controls. Accordingly, a decreased expression of MMP-1 mRNA in endothelial cells was detectable. Other MMPs were not affected. Affecting all dermal wound-healing-related cell types, TGF-beta antisense oligonucleotide technology may be a potential therapeutic option for the inhibition of proteolytic tissue destruction in chronic wounds. Pharmaceutical intervention in this area ultimately may help clinicians to proactively intervene in an effort to prevent normal wounds from becoming chronic.

Alcohol-related diseases of the mouth and throat

Chronic consumption of alcoholic beverages is an accepted social custom worldwide. In the upper aerodigestive tract, local morphologic, metabolic and functional alterations are present due to alcohol consumption. A clinical link between the chronic consumption of alcohol and head and neck cancer has been observed for decades. While alcohol was described initially as a risk enhancer only in smokers, a number of epidemiological studies have now provided sufficient evidence that chronic alcohol consumption increases the risk of head and neck cancer independent of exposure to tobacco smoke. The systemic effects of alcohol interact with local changes in the morphology and function of the salivary glands. In addition, alcohol leads to 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, leukoplacia and carcinoma. Chronic alcohol consumption is correlated with an increased risk of cancer and an increased mortality in a dose-effect relationship. A number of biologically plausible mechanisms exist by which alcohol may cause cancer. These mechanisms are discussed in this article.