Felix Peter Koch
Research interests
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InterestsOrthognathic Surgery, Maxillofacial Surgery, Oral Cancer, Oral Pathology, Maxillofacial Abnormalities, Orthognathic Surgical Procedures, Maxillofacial Injuries, Oral Medicine, Dental Implants, Osseointegration, Bone Regeneration, Tissue Engineering, Stem Cell, Scaffold, Stem Cell Differentiation, Regenerative Medicine, Maxillofacial Development, Biomedical Engineering, Stem Cell Isolation, Facial trauma, Oral Surgery, Biomaterials, Drug Delivery, Drug Delivery Systems, Nanomedicine, Nanoparticles Drug Delivery, Plastic and reconstructive surgery, Microsurgery, Autologous Transplantation, Stem Cell Transplantation
Publications
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1.70Impact points
GDF-5 and BMP-2 Regulate Bone Cell Differentiation by Gene Expression of MSX1, MSX2, Dlx5, and Runx2 and Influence OCN Gene Expression In Vitro.
The International journal of periodontics & restorative dentistry. 06/2012; 32(3):285-93.
Recombinant human growth/differentiation factor 5 (rhGDF-5) and recombinant human bone morphogenetic protein 2 (rhBMP-2), as members of the transforming growth factor Β family, influence bone formation and differentiation. This in vitro osteoblast cell culture study investigated the molecular biolog... [more] Recombinant human growth/differentiation factor 5 (rhGDF-5) and recombinant human bone morphogenetic protein 2 (rhBMP-2), as members of the transforming growth factor Β family, influence bone formation and differentiation. This in vitro osteoblast cell culture study investigated the molecular biologic effect of these growth factors on regulator gene expression of the homebox proteins MSX1 and MSX2 as well as distal-less homebox 5 (Dlx5) and runt-related transcription factor 2 (Runx2/Cbfa1). Concerning effector genes, the messenger ribonucleic acids of osteocalcin (OCN) were quantified using a reverse transcriptase real-time polymerase chain reaction. Over a period of 15 days, osteoblasts were stimulated and analyzed at days 1, 2, 5, 10, and 15. rhGDF-5 and rhBMP-2 were applied in concentrations of 100, 500, and 1,000 ng/mL. The results showed enhanced gene expression of MSX1 and MSX2 by the lower rhGDF-5 concentration (100 ng/mL) during the first 48 hours and a marginally enhanced gene expression of Runx2 and OCN in a dose-dependent manner. The rhBMP-2 stimulation showed enhanced MSX1 and MSX2 gene expression with peaks at 24 and 240 hours; Runx2 and OCN were more highly expressed than the unstimulated control with the 100-ng/mL concentration. rhGDF-5 seems to stimulate early osteoblast differentiation and extracellular matrix production, while rhBMP-2 seems to boost early and late osteoblast differentiation. Low growth factor concentrations appeared to be more effective in terms of gene expression.
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3.12Impact points
GDF 15 as an anti-apoptotic, diagnostic and prognostic marker in oral squamous cell carcinoma.
Oral oncology. 02/2012;
Growth-differentiation factor 15 (GDF 15) is involved in tumor pathogenesis and its expression is increased in many types of cancers. Functional effects of GDF 15 on oncogenesis of oral squamous cell carcinoma (OSCC) remain unclear. Therefore, the aim of this study was to examine the apoptotic chara... [more] Growth-differentiation factor 15 (GDF 15) is involved in tumor pathogenesis and its expression is increased in many types of cancers. Functional effects of GDF 15 on oncogenesis of oral squamous cell carcinoma (OSCC) remain unclear. Therefore, the aim of this study was to examine the apoptotic characteristics of GDF 15 in OSCC cell lines in vitro and to analyze serum GDF 15 concentrations as a diagnostic and prognostic tumor marker for OSCC in vivo. Caspase activity was assessed in OSCC cell lines with the Caspase-Glo 3/7 system. Serum GDF 15 concentrations from 64 patients with histopathological proven OSCC and from 30 healthy volunteers were measured using an enzyme-linked immunosorbent assay. In 21 patients, serum GDF 15 was also analyzed postoperatively. In vitro, treatment of OSCC cell lines with GDF 15 reduced Caspase 3/7 activity significantly (p<0.05). In vivo, serum GDF 15 concentrations of the OSCC patients in all stages of OSCC were significantly higher than those of the healthy subjects (p<0.0001). After surgery, GDF 15 concentrations declined significantly from 1545±774pg/ml preoperative to 953±438pg/ml postoperative (p=0.003). The median survival time of OSCC patients with GDF 15 levels below 875pg/ml was significantly higher than of OSCC patients with GDF 15 levels above or equal 875pg/ml (p=0.031). Determination of receiver operating characteristic curves (ROC) showed a respective area under the ROC curve (AUC) of 0.943. The anti-apoptotic effect of GDF 15 in OSCC cell lines was shown in vitro. In vivo, significant elevated serum GDF 15 levels with prognostic value in OSCC-patients were seen for the first time. The results indicate that GDF15 may be used as a potential marker for diagnosis and prognosis of this entity.
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2.23Impact points
Effectiveness of autofluorescence to identify suspicious oral lesions--a prospective, blinded clinical trial.
Clinical oral investigations. 12/2011; 15(6):975-82.
Regular screening through white light inspection of the entire oral mucosa is the most important examination method to identify precancerous lesions and early oral carcinoma. Additionally, the physiologic autofluorescence of the oral mucosa has been described as a novel screening method for the dete... [more] Regular screening through white light inspection of the entire oral mucosa is the most important examination method to identify precancerous lesions and early oral carcinoma. Additionally, the physiologic autofluorescence of the oral mucosa has been described as a novel screening method for the detection of mucosal lesions that are not visible by white light. This study aimed to evaluate the sensitivity and specificity of the autofluorescence examination. Seventy-eight patients were examined in this study. All of them suffered from suspicious oral mucosal lesions. Two different investigation methods were applied: the standard examination by white light and an examination by a novel light source of 400 nm that evoked a green light emission (>500 nm) in normal mucosa. It was proposed that malignant oral mucosal lesions show different autofluorescence characteristics than the green autofluorescence of healthy mucosa. Red autofluorescence indicated SCC with a sensitivity of 20% and a specificity of 98%. The results showed that dysplasia and carcinoma could be identified with a sensitivity of 96% and a specificity of 18% by using the autofluorescence method. The sensitivity decreased according to the grade of mucosal keratosis and was influenced by the localisation of the lesion. In conclusion, benign as well as malignant oral lesions could not be distinguished by a diminished autofluorescence signal. A red autofluorescence signal, however, could indicate cancerous processes of the oral mucosa.
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4.64Impact points
Bone marrow concentrate and bovine bone mineral for sinus floor augmentation: a controlled, randomized, single-blinded clinical and histological trial--per-protocol analysis.
Tissue engineering. Part A. 04/2011; 17(17-18):2187-97.
The purpose of this work was to evaluate the potential of substituting autogenous bone (AB) by bone marrow aspirate concentrate (BMAC). Both AB and BMAC were tested in combination with a bovine bone mineral (BBM) for their ability of new bone formation (NBF) in a multicentric, randomized, controlled... [more] The purpose of this work was to evaluate the potential of substituting autogenous bone (AB) by bone marrow aspirate concentrate (BMAC). Both AB and BMAC were tested in combination with a bovine bone mineral (BBM) for their ability of new bone formation (NBF) in a multicentric, randomized, controlled, clinical and histological noninferiority trial. Forty-five severely atrophied maxillary sinus from 26 patients were evaluated in a partial cross-over design. As test arm, 34 sinus of 25 patients were augmented with BBM and BMAC containing mesenchymal stem cells. Eleven control sinus from 11 patients were augmented with a mixture of 70% BBM and 30% AB. Biopsies were obtained after a 3-4-month healing period at time of implant placement and histomorphometrically analyzed for NBF. NBF was 14.3%±1.8% for the control and nonsignificantly lower (12.6%±1.7%) for the test (90% confidence interval: -4.6 to 1.2). Values for BBM (31.3%±2.7%) were significantly higher for the test compared with control (19.3%±2.5%) (p<0.0001). Nonmineralized tissue was lower by 3.3% in the test compared with control (57.6%; p=0.137). NBF after 3-4 months is equivalent in sinus, augmented with BMAC and BBM or a mixture of AB and BBM. This technique could be an alternative for using autografts to stimulate bone formation.
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Osteonecrosis of the jaw related to sunitinib.
Oral and maxillofacial surgery. 03/2011; 15(1):63-6.
CASE REPORT: A 59-year-old male patient was referred to the hospital with exposed bone measuring 10 mm in diameter in the posterior, left-side region of the lower jaw. Two months previous, the first molar had been extracted. The patient had contracted renal cell carcinoma and had been treated by nep... [more] CASE REPORT: A 59-year-old male patient was referred to the hospital with exposed bone measuring 10 mm in diameter in the posterior, left-side region of the lower jaw. Two months previous, the first molar had been extracted. The patient had contracted renal cell carcinoma and had been treated by nephrectomy in 2003. Soft tissue metastases occurred. After initial therapy with interferon and vinblastine, a relapse occurred and the therapy was changed to sorafenib, followed by sunitinib. Osteonecrosis of the lower jaw appeared 1 year after initial and exclusive therapy with sunitinib. CONCLUSIONS: Bisphosphonates had never been applied. With increasing application of multi-kinase inhibitors, complications due to osteonecrosis could occur more frequently.
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The influence of bisphosphonates on human osteoblast migration and integrin aVb3/tenascin C gene expression in vitro.
Head & face medicine. 02/2011; 7(1):4.
Bisphosphonates are therapeutics of bone diseases, such as Paget's disease, multiple myeloma or osteoclastic metastases. As a severe side effect the bisphosphonate induced osteonecrosis of the jaw (BONJ) often requires surgical treatment and is accompanied with a disturbed wound healing.Therefor... [more] Bisphosphonates are therapeutics of bone diseases, such as Paget's disease, multiple myeloma or osteoclastic metastases. As a severe side effect the bisphosphonate induced osteonecrosis of the jaw (BONJ) often requires surgical treatment and is accompanied with a disturbed wound healing.Therefore, the influence on adhesion and migration of human osteoblasts (hOB) after bisphosphonate therapy has been investigated by morphologic as well as gene expression methods. By a scratch wound experiment, which measures the reduction of defined cell layer gap, the morphology and migration ability of hOB was evaluated. A test group of hOB, which was stimulated by zoledronate 5 × 10(-5)M, and a control group of unstimulated hOB were applied. Furthermore the gene expression of integrin aVb3 and tenascin C was quantified by Real-Time rtPCR at 5 data points over an experimental period of 14 days. The bisphosphonates zoledronate, ibandronate and clodronate have been compared with an unstimulated hOB control. After initially identical migration and adhesion characteristics, zoledronate inhibited hOB migration after 50 h of stimulation. The integrinavb3 and tenascin C gene expression was effected by bisphosphonates in a cell line dependent manner with decreased, respectively inconsistent gene expression levels over time. The non-nitrogen containing bisphosphonates clodronate led to decreased gene expression levels. Bisphosphonates seem to inhibit hOB adhesion and migration. The integrin aVb3 and tenascin C gene expression seem to be dependent on the cell line. BONJ could be enhanced by an inhibition of osteoblast adhesion and migration. The gene expression results, however, suggest a cell line dependent effect of bisphosphonates, which could explain the interindividual differences of BONJ incidences.
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2.23Impact points
The influence of bisphosphonates on viability, migration, and apoptosis of human oral keratinocytes--in vitro study.
Clinical oral investigations. 01/2011; 16(1):87-93.
Bisphosphonate-associated osteonecrosis of the jaw (BP-ONJ) is one of the most often seen side effects in patients treated with bisphosphonates, presenting clinically as a non-healing wound. One theory of BP-ONJ etiology describes a negative effect on soft tissues, especially on keratinocytes, which... [more] Bisphosphonate-associated osteonecrosis of the jaw (BP-ONJ) is one of the most often seen side effects in patients treated with bisphosphonates, presenting clinically as a non-healing wound. One theory of BP-ONJ etiology describes a negative effect on soft tissues, especially on keratinocytes, which play an important role in oral wound healing and oral soft tissue regeneration. A high cell viability of keratinocytes, which can migrate to the affected location, is essential for wound healing. The aim of this in vitro study was to investigate the effect of differently potent bisphosphonates on human oral keratinocytes (HOK).Three nitrogen-containing bisphosphonates (ibandronate, pamidronate, and zoledronate) and one non-nitrogen-containing bisphosphonate (clodronate) were compared concerning their potency on cell viability (calcein assay and MTT assay), migration ability (Boyden chamber migration assay and scratch wound proliferation assay), and apoptosis (TUNEL assay) of HOK.The nitrogen-containing bisphosphonates, particularly highly potent pamidronate and zoledronate preparations, had a strong negative influence on cell viability, migration ability, and apoptosis of HOK. The non-nitrogen-containing clodronate even increased cell viability in higher concentrations.This study demonstrates that bisphosphonates have a strong influence on HOK on different cellular levels like cell viability, migration ability, and apoptosis rate. The results support the theory that BP-ONJ is a multifactorially caused disease.Furthermore, this in vitro study confirms the theory that perioperative interruption of bisphosphonate application during dental surgical procedures might be feasible to promote better tissue regeneration and wound healing.
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2.92Impact points
A prospective, randomized pilot study on the safety and efficacy of recombinant human growth and differentiation factor-5 coated onto β-tricalcium phosphate for sinus lift augmentation.
Clinical oral implants research. 11/2010; 21(11):1301-8.
The aim of this prospective, randomized clinical trial was to investigate the potential of recombinant human growth and differentiation factor-5 (rhGDF-5) coated onto β-tricalcium phosphate (β-TCP) (rhGDF-5/β-TCP) to support bone formation after sinus lift augmentation. In total, 31 patients partici... [more] The aim of this prospective, randomized clinical trial was to investigate the potential of recombinant human growth and differentiation factor-5 (rhGDF-5) coated onto β-tricalcium phosphate (β-TCP) (rhGDF-5/β-TCP) to support bone formation after sinus lift augmentation. In total, 31 patients participated in this multicenter clinical trial. They required a two-stage unilateral maxillary sinus floor augmentation (residual bone height <5 mm). According to a parallel-group design, the patients were randomized to three treatment groups: (a) augmentation with rhGDF-5/β-TCP and a 3-month healing period, (b) augmentation with rhGDF-5/β-TCP and a 4-month healing period and (c) medical device β-TCP mixed with autologous bone and a 4-month healing period. The primary study objective was the area of newly formed bone within the augmented area as assessed by histomorphometric evaluation of trephine bur biopsies. The osseous regeneration was similar in each treatment group; the amount of newly formed bone ranged between 28% (± 15.5%) and 31.8% (± 17.9%). Detailed analysis of histological data will be published elsewhere. As secondary efficacy variables, the augmentation height at the surgery site was measured by radiography. The largest augmentation was radiologically achieved in the rhGDF-5/β-TCP - 3-month and the rhGDF-5/β-TCP - 4-month treatment groups. As safety parameters, adverse events were recorded and anti-drug antibody levels were evaluated. Most of the adverse events were judged as unrelated to the study medication. Four out of 47 (8.5%) implants failed in patients treated with rhGDF-5/β-TCP, a result that is in agreement with the general implant failure rate of 5-15%. Transiently very low amounts of anti-rhGDF-5 antibodies were detected in some patients who received rhGDF-5, which was not related to the bone formation outcome. rhGDF-5/β-TCP was found to be effective and safe as the control treatment with autologous bone mixed β-TCP in sinus floor augmentation. Thus, further investigation regarding efficacy and safety will be carried out in larger patient populations.
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2.23Impact points
Influence of bisphosphonates on the osteoblast RANKL and OPG gene expression in vitro.
Clinical oral investigations. 10/2010; 16(1):79-86.
Bisphosphonates are widely used in the clinical treatment of bone diseases with increased bone resorption. In terms of side effects, they are widely known to be associated with osteonecrosis of the jaw (BONJ). The objective of this study was to evaluate the effect of bisphosphonates on the gene expr... [more] Bisphosphonates are widely used in the clinical treatment of bone diseases with increased bone resorption. In terms of side effects, they are widely known to be associated with osteonecrosis of the jaw (BONJ). The objective of this study was to evaluate the effect of bisphosphonates on the gene expression of receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) in vitro. Nitrogen-containing and non-nitrogen containing bisphosphonates have been compared. Human osteoblasts were stimulated with zoledronate and ibandronate at concentrations of 5 × 10(-5) M, 5 × 10(-6) M, and 5 × 10(-7) M over the experimental period of 14 days. Furthermore, the hOB cell lines were stimulated by clodronate at concentrations of 5 × 10(-3) M, 5 × 10(-5) M, and 5 × 10(-6) M. At each point in time, the gene expression levels of RANKL and OPG were quantified by real-time RT-PCR. The results showed a moderate enhancement of OPG gene expression whereas RANKL gene expression was strongly increased by nitrogen-containing bisphosphonates reaching a maximum after 14 days at high concentrations of 5 × 10(-5) M. Lower concentrations did not enhance the RANKL and OPG expression considerably. The non-nitrogen-containing bisphosphonate clodronate, however, effected OPG and RANKL gene expression much less, even at higher concentrations of 5 × 10(-3) M. The above-mentioned data suggest an enhanced RANKL/OPG gene expression after stimulation by bisphosphonates. Interestingly, clodronate might have little influence on osteoblast/osteoclast interaction with respect to OPG and RANKL gene expression.
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1.25Impact points
Zoledronate, ibandronate and clodronate enhance osteoblast differentiation in a dose dependent manner--a quantitative in vitro gene expression analysis of Dlx5, Runx2, OCN, MSX1 and MSX2.
Journal of cranio-maxillo-facial surgery : official publication of the European Association for Cranio-Maxillo-Facial Surgery. 10/2010; 39(8):562-9.
Bisphosphonates are widely used in the clinical treatment of bone diseases with increased bone resorption. In terms of side effects, they are known to be associated with osteonecrosis of the jaw (BONJ). There are two groups of bisphosphonates: the nitrogen-containing bisphosphonates, e.g. zoledronat... [more] Bisphosphonates are widely used in the clinical treatment of bone diseases with increased bone resorption. In terms of side effects, they are known to be associated with osteonecrosis of the jaw (BONJ). There are two groups of bisphosphonates: the nitrogen-containing bisphosphonates, e.g. zoledronate and ibandronate, and the non-nitrogen-containing bisphosphonates, e.g. clodronate. Their impact on bone metabolism seems to differ. The objective of this study was to compare the osteogenic differentiation potency of these two pharmacologic groups. Human osteoblasts were stimulated with zoledronate and ibandronate at concentrations of 5×10(-5) M, 5×10(-6) M and 5×10(-7) M over the experimental periods of 1, 2, 5, 10 and 14 days. Clodronate was applied with concentrations of 5×10(-3), 5×10(-5) M and 5×10(-6) M. At each time point, the cells were dissolved, the mRNA extracted, and the gene expression level of the osteoblast specific differentiation markers of the homeobox transcription factors MSX1 and MSX2, the distal-less homeobox 5 (Dlx5), the Runt-related transcription factor 2 (Runx2/CBF1a) and osteocalcin (OCN) were quantified by Real-Time PCR. The gene expression was compared to an unstimulated osteoblast cell culture as control. The results showed a significant difference between the nitrogen-containing and the non-nitrogen-containing bisphosphonates. Zoledronate and ibandronate at concentrations of 5×10(-5) M enhanced the gene expression of all differentiation markers by several hundred folds compared to unstimulated control after 10 days, whereas clodronate had less influence on gene expression, even at higher concentrations of 5×10(-3) M. Lower concentrations of zoledronate and ibandronate, however, led to a decreased gene expression. These data confirm the results of other studies which have shown the osteogenic stimulus on osteoblasts in a dose dependent manner. The nitrogen-containing bisphosphonates appear to enhance bone density by stimulation of osteoblast differentiation. Non-nitrogen-containing bisphosphonates seem to have less influence on osteoblast differentiation.
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2.23Impact points
Diagnostic efficiency of differentiating small cancerous and precancerous lesions using mucosal brush smears of the oral cavity-a prospective and blinded study.
Clinical oral investigations. 07/2010;
The aim of this study was to evaluate the diagnostic accuracy of oral brush biopsy to identify early malignancy. One hundred and eighty-six brush biopsies of suspicious mucosal lesions were obtained, haematoxilin and eosin (H&E)-stained and compared with the histology of conventional excision bi... [more] The aim of this study was to evaluate the diagnostic accuracy of oral brush biopsy to identify early malignancy. One hundred and eighty-six brush biopsies of suspicious mucosal lesions were obtained, haematoxilin and eosin (H&E)-stained and compared with the histology of conventional excision biopsies of the same site performed concomitantly. The sensitivity for identifying squamous cell carcinoma (SCC) was 88.5%. High-risk lesions including squamous intraepithelial neoplasia (SIN II, SIN III) and SCC were identified with a sensitivity of 86.4%, using a pap-analogous classification, which is considered to be carcinomatous, as well as moderate and severe dysplastic cells positive. Depending on the cytopathologic definition for malignancy and the tumour size, the test accuracy varied: Extending the cytopathologic criteria for malignancy by defining all dysplastic or malignant cytopathologic findings as positive, the sensitivity was increased to 95.2% at the expense of the specificity, which was reduced from 94.9% to 82.3%. Separately analysing SCCs of less than 20 mm, the sensitivity was reduced by 9.5% to 78%. Although small malignant lesions seem to be less reliable by the conventional oral brush biopsy, it is a useful screening instrument for early diagnosis of suspicious, epithelial lesions and could therefore contribute to improved cancer prognosis.
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2.92Impact points
Osseointegration of one-piece zirconia implants compared with a titanium implant of identical design: a histomorphometric study in the dog.
Clinical oral implants research. 03/2010; 21(3):350-6.
The aim of this study was to evaluate osseointegration of one-piece zirconia vs. titanium implants depending on their insertion depth by histomorphometry. Four one-piece implants of identical geometry were inserted on each side of six mongrel dogs: (1) an uncoated zirconia implant, (2) a zirconia im... [more] The aim of this study was to evaluate osseointegration of one-piece zirconia vs. titanium implants depending on their insertion depth by histomorphometry. Four one-piece implants of identical geometry were inserted on each side of six mongrel dogs: (1) an uncoated zirconia implant, (2) a zirconia implant coated with a calcium-liberating titanium oxide coating, (3) a titanium implant and (4) an experimental implant made of a synthetic material (polyetheretherketone). In a split-mouth manner they were inserted in submerged and non-submerged gingival healing modes. After 4 months, dissected blocks were stained with toluidine blue in order to histologically assess the bone-to-implant contact (BIC) rates and the bone levels (BL) of the implants. All 48 implants were osseointegrated clinically and histologically. Histomorphometrically, BL in the crestal implant part did not differ significantly with regard to material type or healing modality. The submerged coated zirconia implants tended to offer the most stable crestal BL. The histometric results reflected the different healing modes by establishing different BL. The median BIC of the apical implant part of the zirconia and titanium group amounted to 59.2% for uncoated zirconia, 58.3% for coated zirconia, 26.8% for the synthetic material and 41.2% for titanium implants. Within the limits of this animal study, it is concluded that zirconia implants are capable of establishing close BIC rates similar to what is known from the osseointegration behaviour of titanium implants with the same surface modification and roughness.
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3.12Impact points
Influence of class M1 glutathione S-transferase (GST Mu) polymorphism on GST M1 gene expression level and tumor size in oral squamous cell carcinoma.
Oral oncology. 02/2010; 46(2):128-33.
Glutathione S-transferases (GST) are antioxidant enzymes and oxidative stress markers in oral carcinogenesis. They present a system of polymorphic proteins. Some variants are associated with increased sensitivity to toxic compounds, as it is known for the GSTM1-null variant allele. However, the infl... [more] Glutathione S-transferases (GST) are antioxidant enzymes and oxidative stress markers in oral carcinogenesis. They present a system of polymorphic proteins. Some variants are associated with increased sensitivity to toxic compounds, as it is known for the GSTM1-null variant allele. However, the influence of the GSTM1 allele variant genotype on GSTM1-mRNA quantity in oral squamous cell carcinoma (OSCC) and normal mucosa as well as the impact on prognosis remains unclear. The genotype for GSTM1 (mutation vs. wild type) was determined by polymerase chain reaction (PCR) using genomic DNA extracted from peripheral blood from 28 OSCC patients. From the same patients, 28 pairs of OSCC cells and normal oral mucosal cells were obtained by brush biopsy. mRNA was extracted from these paired samples and the expression levels of GSTM1 were examined by real-time reverse transcriptase qPCR (RT-qPCR). The mRNA expression of the OSCC samples was normalized against an external standard, as well as to the corresponding normal mucosa. The coincidence of GSTM1 genotype and GSTM1-mRNA-expression level was examined. In 15 patients (54%), the null genotype GSTM1 was present. In the GSTM1-null allele group, the GSTM1 gene expression level was determined at 1.63 (mean: 3.08; SD 3.4) folds vs. 3.6 (mean: 10.5; SD 14.2) folds in the group with the positive genotype (p=0.06), if calibrated vs. individual normal mucosa. More T3 and T4 OSCCs (+38%), higher UICC stadia (+38%) and more lymphatic metastasis (+28%) were seen in the group with the negative allele. Furthermore, positive GSTM1 genotype and enhanced GSTM1 gene expression was accompanied with increased tumor size, lymphatic metastasis status and UICC stadium. A coincidence of null type GSTM1 and lowered GSTM1 gene expression was observed. The larger tumors and more frequent lymph node metastases in this group could be explained by the insufficient cell protection by GST.
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The impact of bisphosphonates on the osteoblast proliferation and Collagen gene expression in vitro.
Head & face medicine. 01/2010; 6:12.
Bisphosphonates are widely used in the clinical treatment of bone diseases with increased bone resorption. In terms of side effects, they are known to be associated with osteonecrosis of the jaw (BONJ).The objective of this study was to evaluate the effect of bisphosphonates on osteoblast proliferat... [more] Bisphosphonates are widely used in the clinical treatment of bone diseases with increased bone resorption. In terms of side effects, they are known to be associated with osteonecrosis of the jaw (BONJ).The objective of this study was to evaluate the effect of bisphosphonates on osteoblast proliferation by cell count and gene expression analysis of cyclin D1 in vitro. Furthermore, the gene expression of the extracellular matrix protein collagen type I was evaluated. Nitrogen-containing and non-nitrogen-containing bisphosphonates have been compared on gene expression levels. Human osteoblast obtained from hip bone were stimulated with zoledronate, ibandronate and clodronate at concentrations of 5 x 10-5M over the experimental periods of 1, 2, 5, 10 and 14 days. At each point in time, the cells were dissolved, the mRNA extracted, and the gene expression level of cyclin D1 and collagen type I were quantified by Real-Time RT-PCR. The gene expression was compared to an unstimulated osteoblast cell culture for control. The proliferation appeared to have been influenced only to a small degree by bisphosphonates. Zolendronate led to a lower cyclin D1 gene expression after 10 days. The collagen gene expression was enhanced by nitrogen containing bisphosphonates, decreased however after day 10. The non-nitrogen-containing bisphosphonate clodronate, however, did not significantly influence cyclin D1 and collagen gene expression. The above data suggest a limited influence of bisphosphonates on osteoblast proliferation, except for zoledronate. The extracellular matrix production seems to be initially advanced and inhibited after 10 days. Interestingly, clodronate has little influence on osteoblast proliferation and extracellular matrix production in terms of cyclin D1 and collagen gene expression.
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Zoledronate, ibandronate and clodronate enhance osteoblast differentiation in a dose dependent manner – A quantitative in vitro gene expression analysis of Dlx5, Runx2, OCN, MSX1 and MSX2
Journal of Cranio-Maxillofacial Surgery.
Bisphosphonates are widely used in the clinical treatment of bone diseases with increased bone resorption. In terms of side effects, they are known to be associated with osteonecrosis of the jaw (BONJ). There are two groups of bisphosphonates: the nitrogen-containing bisphosphonates, e.g. zoledronat... [more] Bisphosphonates are widely used in the clinical treatment of bone diseases with increased bone resorption. In terms of side effects, they are known to be associated with osteonecrosis of the jaw (BONJ). There are two groups of bisphosphonates: the nitrogen-containing bisphosphonates, e.g. zoledronate and ibandronate, and the non-nitrogen-containing bisphosphonates, e.g. clodronate. Their impact on bone metabolism seems to differ.The objective of this study was to compare the osteogenic differentiation potency of these two pharmacologic groups.Human osteoblasts were stimulated with zoledronate and ibandronate at concentrations of 5 × 10−5 M, 5 × 10−6 M and 5 × 10−7 M over the experimental periods of 1, 2, 5, 10 and 14 days. Clodronate was applied with concentrations of 5 × 10−3, 5 × 10−5 M and 5 × 10−6 M. At each time point, the cells were dissolved, the mRNA extracted, and the gene expression level of the osteoblast specific differentiation markers of the homeobox transcription factors MSX1 and MSX2, the distal-less homeobox 5 (Dlx5), the Runt-related transcription factor 2 (Runx2/CBF1a) and osteocalcin (OCN) were quantified by Real-Time PCR. The gene expression was compared to an unstimulated osteoblast cell culture as control.The results showed a significant difference between the nitrogen-containing and the non-nitrogen-containing bisphosphonates. Zoledronate and ibandronate at concentrations of 5 × 10−5 M enhanced the gene expression of all differentiation markers by several hundred folds compared to unstimulated control after 10 days, whereas clodronate had less influence on gene expression, even at higher concentrations of 5 × 10−3 M. Lower concentrations of zoledronate and ibandronate, however, led to a decreased gene expression.These data confirm the results of other studies which have shown the osteogenic stimulus on osteoblasts in a dose dependent manner.The nitrogen-containing bisphosphonates appear to enhance bone density by stimulation of osteoblast differentiation. Non-nitrogen-containing bisphosphonates seem to have less influence on osteoblast differentiation.
Following (1)
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Wilfried Wagner
Johannes Gutenberg-University
