Phillipp Brockmeyer

The time interval between primary surgery and adjuvant therapy determines prognosis of oral squamous cell carcinomas

To estimate the prognosis in patients suffering from oral squamous cell carcinoma (OSCC) and to select a therapy concept, staging tests are performed. Patients with similar characteristics are grouped into AJCC stages [1]. For prognosis analysis, the Cox proportional hazard regression (CR) is most widely used [2]. The random forest approach (RFA), as a new statistical method, facilitates an improved estimation of the survival of patients [3–7]. In a retrospective analysis of 106 OSCC patients, we investigated how different clinical and pathological factors affect the overall survival (OS) and the incidence of first local recurrence (LR). We combined RFA, competing risk regression (CRR), and CR to identify major risk factors for a poor clinical outcome.

Increase of homogenous new bone formation using osteoinductive factor rhGDF‐5 during sinus floor augmentation in Goettingen Minipigs

OBJECTIVES The aim of this study was to test the hypothesis that recombinant human growth and differentiation factor-5 (rhGDF-5) induces an increased and homogenous distribution of new bone formation across the entire volume of sinus floor augmentation in 12 Goettingen Minipigs. MATERIAL AND METHODS In a randomized split-mouth design, one maxillary sinus was augmented with the bone substitute β-TCP, whereas a combination of β-TCP and the osteoinductive growth factor rhGDF-5 was used on the contralateral side. To evaluate the influence of dose and time on the effectiveness of the factor, two different concentrations of rhGDF-5 (400 μg and 800 μg) and healing periods (4 and 12 weeks) were each analysed. RESULTS After 4 weeks, a homogenous gradient of bone formation could be observed for all dosage groups, with decreasing bone density from the local bone towards the sinus membrane. Both test groups, however, achieved a higher total level of bone formation compared with the control group, which was only significant in the low-dose group (P = 0.0184). After 12 weeks, the influence of the growth factor significantly depends on the region (P = 0.023). In the low-dose group, the new bone formation did not differ significantly within the examined regions of the graft (P = 0.1118), suggesting a homogeneous bone formation over the entire augmentation. The gradient of the high-dose group was similar to the control group with a decrease of local bone development. CONCLUSIONS rhGDF-5 delivered on a β-TCP scaffold material leads to an increase in homogeneous new bone formation across the entire volume of the sinus floor augmentation.

Elongated styloid process in patients with temporomandibular disorders — Is there a link?

BACKGROUND Elongated styloid processes may display clinical signs that can easily be confused with symptoms associated with temporomandibular disorders (TMD). Thus, the present study aimed to investigate alterations of the styloid process in patients with TMD. METHODS Temporomandibular joint (TMJ) X-ray images of 192 patients with RDC/TMD diagnoses were examined retrospectively. On each side, the styloid process and mandibular ramus were evaluated regarding length as well as sagittal angulation. Data were statistically analyzed using two-way ANOVA, Pearsons r and Kruskal-Wallis test. In order to confirm the accuracy of the obtained X-ray measurements, the available cone-beam-computed tomographies (CBCT) of the subjects were also examined as reference standard and compared with the X-ray TMJ data by using Bland-Altman analysis. RESULTS In a group of TMD patients we assessed a mean styloid length of 40.8mm over both genders. In female subjects the means of length and angulation of the styloid process were 40.4mm and 54.9°, male subjects showed means of 42.1mm and 63.4°. The mean height of the mandibular ramus in males was significantly higher than the same measurement in females (66.8mm vs 59.7mm). Styloid length in relation to ramus height (relative styloid length) was significantly larger in females. No significant correlations between RDC/TMD diagnoses and process length as well as process angle were found. A Bland-Altman analysis revealed conformity of CBCT and digital X-ray results. CONCLUSION The mean styloid length measured in a group of TMD patients is referred to as elongated, whereas females showed longer styloid in relation to body height. However, it appears that alterations of the styloid are not related to TMD diagnoses.

High mast cell density indicates a longer overall survival in oral squamous cell carcinoma.

This study evaluates the effects of tumour-associated mast cells on the prognosis of patients suffering from oral squamous cell carcinoma (OSCC). Tryptase-positive (MCT+) and CD117-positive (CD117+) mast cells were immunohistochemically evaluated in tissue samples of 118 OSCC patients. Besides, various clinicopathological parameters, the influence of the MCT+ and CD117+ mast cell density on overall survival and the incidence of first local recurrence was analysed by Cox regression and competing risk regression. Among all investigated parameters, multiple Cox regression revealed a significant influence of the MCT+ (cut-off at 14.87 mast cells/mm2 stroma; p = 0.0027) and CD117+ mast cell density (cut-off at 33.19 mast cells/mm2 stroma; p = 0.004), the age at primary diagnosis, and the T and N stage (all p-values < 0.05) on overall survival. Patients with a low mast cell density showed a significantly poorer overall survival rate compared to those with a high mast cell density in the tumour-associated stroma. Competing risk regression revealed a significant influence of the resection status (R) on the incidence of first local recurrence (p = 0.0023). A high mast cell density in the tumour-associated stroma of oral squamous cell carcinoma indicates a longer patient survival.

Generation of highly differentiated BHY oral squamous cell carcinoma multicellular spheroids

Three-dimensional (3D) multicellular spheroids (MCS) are considered suitable models in cancer research and anticancer drug development. Although studying the complex tumour characteristics from all different degrees of malignancy is vital, MCS generation has only been described in a few moderately- and poorly differentiated oral squamous cell carcinoma (OSCC) cell lines. No previous study has demonstrated the MCS formation in a highly differentiated OSCC cell line. For the first time, the present study aimed to generate MCS from the highly differentiated OSCC cell line BHY. BHY spheroids were grown in three independent experiments in 96-well plates through the use of the liquid overlay technique. Although BHY cells are grow slowly and are difficult to culture, they formed compact MCS within 24 h. After 3 days of incubation, no further increase in spheroid size was observed. MCS were harvested, paraffin-embedded and 2 µm tissue sections were prepared for further analysis. The diameter and volume of each spheroid were determined. BHY MCS diameter ranged between 46.76 and 233.26 µm, with a volume range from 5.35×104-6.65×106 µm3. In conclusion, using the liquid overlay technique, the highly differentiated OSCC cell line BHY forms different sized spheroids, which may be used for further investigations.

Influence of TGF-β1 on tumor transition in oral cancer cell and BMSC co-cultures

OBJECTIVES TGF-β1 signaling modulates epithelial mesenchymal transitions (EMT) of head and neck squamous cell carcinoma (HNSCC). Bone marrow mesenchymal stromal cells (BMSC) are able to exert a regulating influence on the expression of markers of EMT in HNSCC cells. It was thus the aim of this study to test the hypothesis that TGF-β1 modulates the interactions of tumor transition between BMSCs and HNSCC, affecting the expression of E-cadherin, Vimentin, Snail, Twist, MMP14 and beta-catenin. Furthermore, we analyzed alterations in the AKT-signaling of tumor and stroma cells. MATERIALS AND METHODS BMSCs were isolated from iliac bone marrow aspirates and co-cultured in trans-well permeable membrane wells with tumor cells of the established HNSCC cell line PCI-13. Following the induction with TGF-β1 under serum free conditions the expression of Vimentin and E-Cadherin was assessed via immunofluorescence. A quantitative RT-PCR analysis of tumor transition markers E-cadherin, Vimentin, Snail, Twist, MMP14 and beta-catenin was performed. Changes in AKT-Signaling were identified via protein analysis. RESULTS In non-induced co-cultures, BMSC were able to suppress Vimentin in PCI-13 as a marker of tumor transition. In TGF-β1 induced co-cultures PCI-13 significantly increased the expression of Vimentin, Twist, Snail, MMP14, GSK3a, PRAS40, 4E-BP1, and AMPKa compared to monolayer controls. TGF-β1 co-cultured BMSC demonstrated a significant increase of Snail, PRAS40, mTOR, GSK3a/b, Bad, PDK1 and 4E-BP1. CONCLUSIONS TGF-β1 was able to attenuate the modulating influence of BMSC in co-culture and drive the co-culture towards a progressive tumor transition, affecting the expression of markers of EMT, AKT-Signaling and proliferative checkpoints.

Epigenetic modification suppresses proliferation, migration and invasion of urothelial cancer cell lines

Epigenetic approaches offer additional therapeutic options, including apoptosis induction, modification of cell cycle regulating proteins and the re-expression of pharmaceutical targets, such as hormone receptors. The present study analyzed the effect of the epigenetic modifiers 5-aza-2′-deoxycytidine and Trichostatin A on the proliferative, migratory and invasive behavior of four urinary bladder cancer cell lines (RT-4, RT-112, VMCUB-1 and T-24), and the expression of various matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs). Cell proliferation, migration and invasion assays revealed that treatment with the two epigenetic modifiers resulted in proliferation inhibition in all cell lines, and migration and invasion inhibition in RT-4, RT-112 and T-24 cell lines. Quantitative polymerase chain reaction demonstrated that the mRNA expression of a broad selection of MMPs and their TIMPs was induced in all cell lines, and MMP-14 mRNA expression was suppressed in all cell lines, with the exception of RT-4. In conclusion, epigenetic modifications suppressed the motility and invasiveness of three out of four urothelial cancer cell lines. The inhibitory effect on cell motility appears to be crucial for reduced invasive properties. However, even a broad spectrum of mRNA analysis does not sufficiently explain the loss of invasiveness, as it does not allow for functional conclusions. Further complex urothelial tumour models should be applied to investigate whether epigenetic therapeutic approaches may be an option in urothelial cancer.

Primary stability and osseointegration of dental implants in polylactide modified bone - A pilot study in Goettingen minipigs.

The present study aimed to evaluate primary stability (PS) and osseointegration of dental implants in polylactide [70/30 poly(l-lactide-co-d, l-lactide); (PLDLA)] modified bone in 30 Goettingen minipigs. Each animal received three implants per jaw quadrant. In a split-mouth design, one side of the maxilla and mandible was randomly allocated to the experimental treatment (PLDLA applied into the drill hole before implantation), while the contralateral sides served as intraindividual controls (no PLDLA applied). The required insertion torque and the implant stability quotient (ISQ) were measured during implantation. ISQ, volume density (VD) of new bone formation (NBF), and the bone-implant contact (BIC) were evaluated at the end of the observation period (1, 3, 6, 12, and 24 months, respectively) in six animals each. Across all study groups, the PLDLA treatment resulted in a) a comparable insertion torque, b) an equivalent ISQ, c) a reduced BIC, and d) a reduced VD of NBF, as opposed to the untreated controls. In conclusion, the PLDLA treatment did not affect the PS, but rather led to an impaired osseointegration, which was particularly strong in the compact mandibular bone, and decreased in the spongious maxillary bone. PLDLA induced anchoring in spongious bone should be evaluated in further investigations.