Neoadjuvant Radiochemotherapy Alters the Immune and Metabolic Microenvironment in Oral Cancer-Analyses of CD68, CD163, TGF-β1, GLUT-1 and HIF-1α Expressions

BACKGROUND

The first-line treatment of oral squamous cell carcinoma (OSCC) involves surgical tumor resection, followed by adjuvant radio(chemo)therapy (R(C)T) in advanced cases. Neoadjuvant radio- and/or chemotherapy has failed to show improved survival in OSCC. Recently, neoadjuvant immunotherapy has shown promising therapeutic efficacy in phase 2 trials. In this context, the addition of radio- and chemotherapy is being reconsidered. Therefore, a better understanding of the tumor-biologic effects of neoadjuvant RCT would be beneficial. The current study was conducted on a retrospective cohort of patients who received neoadjuvant RCT for the treatment of oral cancer. The aim of the study was to evaluate the influence of neoadjuvant RCT on the immunological tumor microenvironment (TME) and hypoxic and glucose metabolisms.

METHODS

A cohort of 45 OSSC tissue samples from patients were analyzed before and after RCT (total 50.4 Gy; 1.8 Gy 5× weekly; Cisplatin + 5-Fluorouracil). Immunohistochemistry for CD68, CD163, TGF-β, GLUT-1 and HIF-1α was performed using tissue microarrays and automated cell counting. Differences in expression before and after RCT and associations with histomorphological parameters (T-status, N-status) were assessed using the Mann-Whitney U test.

RESULTS

Tumor resection specimens after neoadjuvant RCT showed a significant decrease in CD68 infiltration and a significant increase in CD163 cell density. The CD68/CD163 ratio was significantly lower after RCT, indicating a shift toward M2 polarization. The GLUT-1 and HIF-1α expressions were significantly lower after RCT. Larger tumors (T3/T4) showed a lower GLUT-1 expression. Other biomarkers were not associated with the T- and N-status.

CONCLUSIONS

Neoadjuvant RCT with 50.4 Gy induced a shift toward the M2 polarization of macrophages in the TME. This change in immune composition is not favorable and may be prognostically negative and counteract immunotherapeutic approaches. In addition, the decreased expressions in GLUT-1 and HIF-1α indicate reductions in the glucose metabolism and hypoxic energy metabolism in response to "high dose" neoadjuvant RCT, which may be therapeutically desirable.

Does surgery affect systemic immune response? a perioperative analysis of TGF-β, IL-8 and CD45RO

Background

The options of (neo-)adjuvant immunotherapy in addition to surgery in the treatment of oral squamous cell carcinoma (OSCC) are steadily increasing, but patients do not always respond to therapy as intended. The objectives of this study were to investigate the systemic perioperative course of the biomarkers CD45RO, TGF-β, and IL-8 in non-tumor-related minor and tumor-related major maxillofacial surgery and to perform association analyses with demographic and histomorphologic parameters. A deeper understanding of surgery-related changes in various of different immune biomarkers could help to better understand the immunologic consequences of surgery which could influence immunotherapeutic protocols.

Methods

Peripheral whole blood from 38 patients was analyzed by real-time quantitative polymerase chain reaction (RT-qPCR) at five different timepoints before and after maxillofacial surgery to detect changes in mRNA expression of the biomarkers TGF-β, IL-8 and CD45RO. All patients underwent general anesthesia to undergo either resection and free flap reconstruction for OSCC or minor maxillofacial surgery (controls). Statistical analysis was done using Mann-Whitney-U test, Wilcoxon test, and Spearman's correlation.

Results

Compared to the preoperative expression, there was a significant postoperative downregulation of CD45RO, TGF-β and IL-8 until the 4th postoperative day (p ≤ 0.003) in OSCC patients. For TGF-β and IL-8, the reduction in expression was significant (p ≤ 0.004) compared to controls. By postoperative day 10, all analyzed parameters converged to baseline levels. Only CD45RO still showed a significant downregulation (p=0.024). Spearman analysis revealed a significant correlation between increased duration of surgery and perioperative reduction in peripheral blood expression of CD45RO, TGF-β and IL-8 (p ≤ 0.004). Perioperative changes in TGF-β and PD-L1 expression were shown to be not correlated. Preoperative TGF-β expression was significantly lower in patients with lymph node metastases (p=0.014).

Conclusion

With regard to the analyzed parameters, major oncologic head-and-neck surgery does not seem to have long-lasting systemic immunologic effects. Reduced CD45RO might be an expression of transient systemic immunosuppression in response to major surgery. The association of duration of surgery with expression changes of immunologic markers supports efforts to keep the duration of surgery as short as possible. As perioperative TGF-β and PD-L1 expression changes are not associated, these results support further investigation of a combined perioperative anti-PD-1 and anti-TGF-β immunotherapy.

Postoperative Changes in Systemic Immune Tolerance Following Major Oncologic versus Minor Maxillofacial Surgery

BACKGROUND

There is increasing evidence of the benefits of adjuvant and neoadjuvant immunotherapy in the treatment of solid malignancies like oral squamous cell carcinoma (OSCC). To optimize (neo-)adjuvant treatment, the systemic immunomodulatory effects of tumor surgery itself need to be considered. Currently, there is little evidence on the immunological effects of major surgery, such as free microvascular flap reconstruction. The current study aims to analyze how and to what extent maxillofacial surgery affects systemic parameters of immune tolerance.

METHODS

A total of 50 peripheral whole blood samples from patients (Group 1 (G1) = extensive OSCC surgery; Group 2 (G2) = free flap reconstruction without persistent malignant disease; Group 3 (G3) = minor maxillofacial surgery) undergoing surgery were included for real-time quantitative polymerase chain reaction (RT-qPCR) to examine changes in mRNA expression of the biomarkers IL-6, IL-10, FOXP3, and PD-L1. Blood samples were taken immediately before and after surgery as well as on the second, fourth, and tenth postoperative days. Differences in mRNA expression between groups and time points were calculated using statistical tests, including Mann-Whitney U-test and Pearson correlation analysis.

RESULTS

Comparing postoperative expression of G1 and G3, there was a significantly higher PD-L1 expression (p = 0.015) in G1 compared to G3 and a significantly lower IL-6 (p = 0.001) and FOXP3 (p = 0.016) expression. Interestingly, IL-10 expression was higher pre- (0.05) and postoperative (p < 0.001) in G1 compared to G3. Additionally, in G1, there was a significant overexpression of IL-10 post-surgery compared to the preoperative value (p = 0.03) and a downregulated expression of FOXP3 between pre- and 2 d post-surgery (p = 0.04). Furthermore, there was a significant correlation between the duration of surgery and the perioperative expression changes of the analyzed biomarkers. As the duration of surgery increased, the expression of IL-10 and PD-L1 increased, and the expression of IL-6 and FOXP3 decreased.

CONCLUSION

Extensive surgery in OSCC patients is associated with a transient shift toward postoperative systemic immune tolerance compared with patients undergoing minor surgery. However, even extensive surgery causes no signs of long-lasting systemic immunosuppression. The degree of immune tolerance that occurred was associated with the duration of surgery. This supports efforts to minimize the duration of surgery.

Alterations in macrophage polarization in the craniofacial and extracranial skeleton after zoledronate application and surgical interventions - an in vivo experiment

Purpose

Medication-related osteonecrosis occurs exclusively in the jaw bones. However, the exact pathogenesis of medication-related osteonecrosis of the jaw (MRONJ) and the unique predisposition of the jaw bones have not been elucidated, making its treatment a challenge. Recent evidence indicates that macrophages might play a pivotal role in MRONJ pathogenesis. The aim of the present study was to compare the macrophage populations between the craniofacial and extracranial skeleton and to investigate the changes induced by zoledronate (Zol) application and surgical interventions.

Materials and methods

An in vivo experiment was performed. 120 wistar rats were randomized to 4 groups (G1, G2, G3, G4). G1 served as an untreated control group. G2 and G4 received Zol injections for 8 weeks. Afterwards, the right lower molar of the animals from G3 and G4 was extracted and the right tibia osteotomized followed by osteosynthesis. Tissue samples were taken from the extraction socket and the tibia fracture at fixed time points. Immunohistochemistry was conducted to determine the labeling indexes of CD68+ and CD163+ macrophages.

Results

Comparing the mandible and the tibia, we observed a significantly higher number of macrophages and a heightened pro-inflammatory environment in the mandible compared to the tibia. Tooth extraction caused an increase of the overall number of macrophages and a shift toward a more pro-inflammatory microenvironment in the mandible. Zol application amplified this effect.

Conclusion

Our results indicate fundamental immunological differences between the jaw bone and the tibia, which might be a reason for the unique predisposition for MRONJ in the jaw bones. The more pro-inflammatory environment after Zol application and tooth extraction might contribute to the pathogenesis of MRONJ. Targeting macrophages might represent an attractive strategy to prevent MRONJ and improve therapy. In addition, our results support the hypothesis of an anti-tumoral and anti-metastatic effect induced by BPs. However, further studies are needed to delineate the mechanisms and specify the contributions of the various macrophage phenotypes.

Recipient bed perfusion as a predictor for postoperative complications in irradiated patients with microvascular free tissue transfer of the head and neck area: a clinical analysis of 191 microvascular free flaps

PURPOSE

Despite microvascular free tissue transfer being the mainstay of care in the reconstruction of larger maxillofacial defects, a significant number of patients experience postoperative complications due to impaired blood supply of the flap. In this context, the early influence of recipient bed perfusion remains unclear, but there is evidence that it is associated with free flap viability immediately after surgery.

METHODS

We analyzed flap and recipient bed perfusion within the first 2 weeks after surgery by using the oxygen-to-see device. One hundred ninety-one patients who underwent free flap surgery in our department were included.

RESULTS

Flow parameters were higher and postoperative complications were less frequent in radial forearm free flaps compared to any other type of flap. Flow parameters of the recipient bed were higher than transferred tissue at all times, implicating flap autonomization is not completed within 2 weeks. Previous radiotherapy significantly decreased flow parameters of the recipient bed but not of the flaps. Furthermore, irradiated patients with postoperative complications were found to have reduced flow parameters of their recipient bed compared to non-irradiated patients with postoperative complications.

CONCLUSION

We conclude that monitoring of recipient bed perfusion is useful for detecting flap compromise of irradiated patients in the early postoperative period.

Lineage-associated connexin 43 expression in bisphosphonate-exposed rat bones

Expression of signaling proteins in bone cells depends on their embryological mesoderm-derived (e.g. tibia) or cranial neural crest (CNC)-derived (e.g. jaw) origin. Connexin 43 (Cx43) is a gap junction protein that plays an essential role in the mode of action of bisphosphonates (BP). This study aimed to investigate Cx43 expression and the influence of BP application on mesoderm- and CNC-derived bone. Using a rat model, molar extraction and tibia osteotomy with (Group 4) or without (Group 3) previous BP application was performed. Untreated (Group 1) and animals selectively treated with BPs (Group 2) served as controls. Cx43 expression was immunohistochemically determined 12 and 16 weeks postoperatively via a labeling index. Cx43 expression in CNC-derived bone was significantly higher compared with mesodermal bone. BP application decreased Cx43 expression; however, detected expression levels were still higher in jawbone (Group 2 tibia vs jaw: 5.83 ± 5.06 vs 23.52 ± 6.42; p = 0.007). During bone healing after surgical intervention (Group 3) there were no expression differences between tibia and jawbone. BP treatment prior to surgery resulted in significantly lower Cx43 expression in CNC-derived compared with tibia bone (Group 4 tibia vs jaw: 56.84 ± 15.57 vs 16.40 ± 5.66; p < 0.01). Increased Cx43 expression in jaw compared with tibia bone is in line with their embryological origins. A significant Cx43 suppression in jawbone after BP application and surgery might contribute to the selectively altered osseous turnover and development of MRONJ in CNC-derived bone.

Endothelial inflammatory and thrombogenic expression changes in microvascular anastomoses - An immunohistochemical analysis

The aim of this study was to investigate intraluminal vessel diameters and endothelial expression levels of pro-inflammatory and -thrombotic mediators in patent and non-patent microvascular anastomoses. Endothelial expression of CD31, VCAM-1, E- and P-Selectin, eNOS, iNOS and PAI-1 was evaluated by immunohistochemistry and compared to non-anastomosed arteries as controls. Intraluminal diameters were determined via H.E.-staining. In 20 human anastomoses (8 patent, 12 non-patent) neither the analysis of endoluminal de-endothelialization (p = 0.966) nor luminal narrowing (p = 0.750) revealed any significant differences between patent and non-patent microanastomoses. Expressions of pro-inflammatory mediators were significantly higher in patent anastomoses compared to controls but did not show any difference compared to non-patent anastomoses (p > 0.050). iNOS was higher in non-patent compared to patent anastomoses (p = 0.030) and controls (p = 0.001), whereas eNOS did not reveal any differences between these groups (p = 0.611 and p = 0.130). In non-patent anastomoses PAI-1 was expressed higher compared to patent anastomoses and controls (p = 0.021 and p < 0.001). Irrespective of their patency, anastomoses are characterized by endothelial dysfunction with a pro-inflammatory and pro-thrombotic milieu. Avoiding endothelial trauma during suturing is essential in order not to aggravate existing endothelial dysfunction in microanastomoses. Additionally, the influence of medication-related changes on anastomoses should be investigated as this is still an indistinctive topic.

Osteocyte necrosis triggers osteoclast-mediated bone loss through macrophage-inducible C-type lectin

Although the control of bone-resorbing osteoclasts through osteocyte-derived RANKL is well defined, little is known about the regulation of osteoclasts by osteocyte death. Indeed, several skeletal diseases, such as bone fracture, osteonecrosis, and inflammation are characterized by excessive osteocyte death. Herein we show that osteoclasts sense damage-associated molecular patterns (DAMPs) released by necrotic osteocytes via macrophage-inducible C-type lectin (Mincle), which induced their differentiation and triggered bone loss. Osteoclasts showed robust Mincle expression upon exposure to necrotic osteocytes in vitro and in vivo. RNA sequencing and metabolic analyses demonstrated that Mincle activation triggers osteoclastogenesis via ITAM-based calcium signaling pathways, skewing osteoclast metabolism toward oxidative phosphorylation. Deletion of Mincle in vivo effectively blocked the activation of osteoclasts after induction of osteocyte death, improved fracture repair, and attenuated inflammation-mediated bone loss. Furthermore, in patients with osteonecrosis, Mincle was highly expressed at skeletal sites of osteocyte death and correlated with strong osteoclastic activity. Taken together, these data point to what we believe is a novel DAMP-mediated process that allows osteoclast activation and bone loss in the context of osteocyte death.

The Special Developmental Biology of Craniofacial Tissues Enables the Understanding of Oral and Maxillofacial Physiology and Diseases

Maxillofacial hard tissues have several differences compared to bones of other localizations of the human body. These could be due to the different embryological development of the jaw bones compared to the extracranial skeleton. In particular, the immigration of neuroectodermally differentiated cells of the cranial neural crest (CNC) plays an important role. These cells differ from the mesenchymal structures of the extracranial skeleton. In the ontogenesis of the jaw bones, the development via the intermediate stage of the pharyngeal arches is another special developmental feature. The aim of this review was to illustrate how the development of maxillofacial hard tissues occurs via the cranial neural crest and pharyngeal arches, and what significance this could have for relevant pathologies in maxillofacial surgery, dentistry and orthodontic therapy. The pathogenesis of various growth anomalies and certain syndromes will also be discussed.

Free Gingival Graft and Collagen Matrix Revascularization in an Enoral Open Wound Situation

PURPOSE

Vestibuloplasty with free gingival grafting is a frequently performed surgical procedure to generate sufficient keratinized mucosa (KM) around dental implants. Avascular porcine collagen matrices (CM) have been proclaimed to be sufficient substitutes as alternatives to free gingival grafts (FGGs). However, the process of graft integration and vascularization is still incompletely understood.

METHODS

In 18 patients a vestibuloplasty in the lower edentulous jaw situation was performed during implant exposure, either with FGGs from the palate or a porcine CM (mucoderm). Tissue perfusion of the soft tissue grafts was measured using laser-doppler-spectrophotometer intraoperatively and on postoperative days 2, 5, 10, 30 and between days 60 and 90. With graft perfusion expressed by oxygen saturation [SO2%], the relative amount of hemoglobin [rHb], blood flow, and velocity [AU] was detected and compared between groups and the surrounding mucosa.

RESULTS

Healing was uneventful in both groups, with mature KM around dental implants after healing. Blood flow and velocity significantly increased until postoperative day 10, comparable to perfusion values of the surrounded mucosa. Intergroup comparisons revelated no significant differences concerning the flow between CM and FGGs. Oxygen saturation also significantly increased within the first 5 postoperative days in both groups. Hemoglobin content did not show any differences during the investigated period.

CONCLUSIONS

The perfusion mainly progresses within the first postoperative week with only minimal further detectable alterations until the final investigation, comparable in both groups. Although integration of FGGs (revascularized) and the CM (new tissue formation) is biologically different, both transplants show comparable perfusion patterns, leading to sufficient KM.

PD1 expression and correlation with its ligands in oral cancer specimens and peripheral blood

OBJECTIVES

This study analyzed the expression of the PD1 receptor in tumor tissue and peripheral blood of oral squamous cell carcinoma (OSCC) patients, and correlated it with the PD1 ligands PD-L1 and PD-L2. The currently low response rates of checkpoint inhibitor treatment in OSCC could be increased by a better understanding of immune checkpoint biology. Despite evidence in the literature for upregulation of PD1 checkpoint ligands in OSCC tissue, there has been no correlation analysis of the PD1 receptor with its ligands in tissue specimens and peripheral blood of OSCC patients.

MATERIALS AND METHODS

An RT-qPCR analysis of PD1 mRNA expression was performed in oral cancer specimens, healthy mucosa, and corresponding blood samples. A cut-off point (COP) was determined and a chi-square (χ²) test was carried out. PD1 expression was correlated with previously reported PD-L1 and PD-L2 expression values using the Spearman test.

RESULTS

Tissue and blood specimens of 48 OSCC patients and 26 healthy individuals were analyzed. PD1 expression in OSCC specimens was significantly increased (p = 0.006) compared with healthy oral mucosa. PD1 overexpression in tissue samples showed a significant association with the presence of malignancy (p = 0.006). PD1 expression in tissue samples showed a significant positive correlation (p < 0.001) with the ligands PD-L1 and PD-L2. In contrast, there was no correlation between PD1 and its ligands in blood samples. However, there was a significant positive correlation (p < 0.001) between the ligands PD-L1 and PD-L2, both in tissue and blood samples.

CONCLUSIONS

Increased PD1 expression might be a manifestation of T-cell exhaustion in OSCC specimens, leading to immune tolerance. PD-L1/PD-L2-PD1 interaction may be a major mediator of local immunosuppression in OSCC, requiring advanced multimodal treatment protocols.

Craniofacial Osteosarcoma-Pilot Study on the Expression of Osteobiologic Characteristics and Hypothesis on Metastasis

Background: Craniofacial osteosarcomas (COS) and extracranial osteosarcomas (EOS) show distinct clinical differences. COS show a remarkably lower incidence of metastases and a better survival. However, in contrast to EOS, they show a poor response to neoadjuvant chemotherapy. Tumor-associated macrophages and their polarization as well as developmental biological signaling pathways are possible candidates for explaining the clinical differences between COS and EOS. The aim of the study was to analyze differential expression of macrophage markers and important regulators of these pathways.

Methods: Twenty osteosarcoma cases (10 COS and 10 EOS) were immunohistochemically stained to assess CD68, CD11c, CD163, MRC1, Gli1, and Gli2 expression. Statistical differences between COS and EOS were tested using the Mann–Whitney U test. Additionally, the paper describes an example of multidisciplinary treatment of a patient suffering from COS and discusses the surgical challenges in treatment and rehabilitation of COS.

Results: COS showed a significantly (p < 0.05) increased infiltration of CD11c-positive M1 macrophages and a shift toward M1 polarization compared to EOS. Additionally, COS revealed a significantly (p < 0.05) lower Gli1 expression than EOS.

Conclusion: The reduced Gli1 expression in COS can be interpreted as reduced activation of the Hedgehog (Hh) signaling pathway. The increased M1 polarization and reduced Hh activation in COS could explain the low incidence of metastases in these osteosarcomas.

Saliva diagnostics in patients suffering from bisphosphonate-associated osteonecrosis of the jaw: Results of an observational study

OBJECTIVE

One of the severe side effects of bisphosphonate (BP) therapy is bisphosphonate-associated osteonecrosis of the jaw (BONJ). However, there is no information available about its pathogenesis. Hence, the aim of this observational study was to contribute to discerning this pathogenesis by comparing salivary quantity and quality in patients with BONJ and undergoing BP treatment.

MATERIALS AND METHODS

This study included 60 patients divided into three groups. The first group consisted of 20 patients with established BONJ, the second group had 20 patients undergoing BP treatment, and the third group comprised 20 healthy individuals. These groups were analysed for the flow rate of stimulated saliva, buffer capacity, and salivary pH level.

RESULTS

Reduced salivation was observed in a significantly high number of patients with established BONJ (n = 8) and those undergoing BP treatment (n = 9) in comparison with the healthy control group (n = 4; p = 0.039). Though the distribution of the mean value of stimulated saliva flow rates in patients undergoing BP treatment was lower than in the control group, the difference was not significant. Moreover, there were no significant differences in the salivary pH level and buffer capacity in patients undergoing BP treatment as compared with the healthy control group.

CONCLUSIONS

It is possible that the quantity of human saliva is affected by BP treatment. This reduction in saliva production could have a negative effect on mucosal health and is perhaps a cofactor in the pathogenesis of BONJ.

Correction to: Long-term endothelial dysfunction in irradiated vessels: an immunohistochemical analysis

Correction to: Strahlenther Onkol 2018 https://doi.org/10.1007/s00066-018-1382-3 The original version of this article unfortunately contained a mistake. The correct version of the Acknowledgements is given ….

Differences in Inflammation and Bone Resorption between Apical Granulomas, Radicular Cysts, and Dentigerous Cysts

INTRODUCTION

Dental cysts can be of inflammatory (radicular cysts) or noninflammatory (dentigerous cysts) origin. Apical periodontitis is a necrosis of the pulp and infection of the root canal causing the development of apical granulomas or radicular cysts. The immunology of granuloma and cyst formation is important because modern root filling materials are immunologically active and can contribute to the resolution of apical granulomas. In contrast, radicular cysts often require apicectomy. A better understanding of the pathophysiology of inflammation and bone resorption in apical periodontitis could be the basis for developing new root filling materials with superior immunomodulatory properties.

METHODS

Forty-one apical granulomas, 23 radicular cysts, and 23 dentigerous cysts were analyzed in this study. A tissue microarray of the 87 consecutive specimens was created, and human leukocyte antigen-DR isotype (HLA-DR)-, CD83-, receptor activator of nuclear factor kappa B ligand-, macrophage colony-stimulating factor (MCSF)-, galectin-3 (Gal3)-, CD4-, and CD8-positive cells were detected by immunohistochemistry. Tissue microarrays were digitized, and the expression of markers was quantitatively assessed.

RESULTS

HLA-DR, CD83, MCSF, and Gal3 expression was significantly (P < .05) higher in radicular cysts compared with apical granulomas. HLA-DR, CD83, MCSF, receptor activator of nuclear factor kappa B ligand, and Gal3 expression in dentigerous cysts was significantly (P < .05) lower than in both periapical lesions (apical granulomas and radicular cysts). CD4 and CD8 infiltration was not statistically different between apical granulomas and radicular cysts. Dentigerous cysts showed a significantly (P < .05) lower T-cell infiltration than apical periodontitis. The CD4/CD8 ratio was not significantly different between the analyzed groups.

CONCLUSIONS

The development of radicular cysts in apical periodontitis is associated with an increased expression of myeloid inflammatory markers and bone resorption parameters. Antigen-presenting cells and myeloid cells might be more relevant for the pathogenesis of apical periodontitis than T cells. Increased inflammation might promote the formation of radicular cysts and more pronounced bone resorption.

Osteoclastic expression of higher-level regulators NFATc1 and BCL6 in medication-related osteonecrosis of the jaw secondary to bisphosphonate therapy: a comparison with osteoradionecrosis and osteomyelitis

Background

With an increasing indication spectrum of antiresorptive drugs, the medication-related osteonecrosis of the jaw secondary to bisphosphonate therapy [MRONJ (BP)] is continuously gaining clinical relevance. Impaired osteoclast function, accompanied by altered cell morphology and expression of osteoclastic effector proteins, contributes to the pathogenesis of MRONJ (BP). However, the underlying regulatory mechanisms at a transcriptional level are unaddressed so far. These mechanisms are crucial to the development of disease-characteristic osteoclastic anomalies, that contribute to the pathogenesis of MRONJ (BP). NFATc1 is considered a master upstream osteoclastic activator, whereas BCL6 acts as osteoclastic suppressor. The present study aimed to elucidate the NFATc1 and BCL6 mediated osteoclastic regulation and activity in MRONJ (BP) compared to osteoradionecrosis (ORN) and osteomyelitis (OM) and normal jaw bone.

Methods

Formalin-fixed jaw bone specimens from 70 patients [MRONJ (BP) n = 30; OM: n = 15, ORN: n = 15, control: n = 10] were analyzed retrospectively for osteoclast expression of NFATc1 and BCL6. The specimens were processed for H&E staining and immunohistochemistry. The histological sections were digitalized and analyzed by virtual microscopy.

Results

Osteoclastic expression of NFATc1 and BCL6 was significantly higher in MRONJ (BP) specimens compared to OM and control specimens. NFATc1 and BCL6 labeling indices revealed no significant differences between MRONJ (BP) and ORN. The ratio of nuclear BCL6+ osteoclasts to cytoplasmic BCL6+ osteoclasts revealed significantly higher values for MRONJ (BP) specimens compared to OM and controls.

Conclusion

This study displays that osteoclasts in MRONJ (BP) tissues feature increased expression of the higher-level regulators, paradoxically of both NFATc1 and BCL6. These observations can help to explain the genesis of morphologically altered and resorptive inactive osteoclasts in MRONJ (BP) tissues by outlining the transcriptional regulation of the pathomechanically relevant osteoclastic effector proteins. Furthermore, they strengthen the etiological delineation of MRONJ (BP) from OM and extend the osteoclast profiles of MRONJ (BP), OM and ORN and thus could lead to a better histopathological differentiation that can improve treatment decision and motivate new therapeutic concepts.

Prognostic significance of PD-L2 expression in patients with oral squamous cell carcinoma-A comparison to the PD-L1 expression profile

BACKGROUND

Despite the observed association of increased PD-L1 expression in peripheral blood of oral squamous cell carcinoma (OSCC) patients with histomorphologic parameters, the role of the PD1 ligands-PD-L1 and PD-L2-is insufficiently understood. Aim of the study was to investigate whether the alterations of PD-L1 and PD-L2 expression in blood are associated with survival and could serve as immune monitoring parameter. Moreover, it should be analyzed if PD-L2 is differentially expressed in tissue and blood samples of OSCC patients compared to healthy controls and if there is an association of PD-L2 expression with histomorphologic and prognostic tumor parameters.

METHODS

PD-L2 mRNA expression was analyzed in tumors and healthy oral mucosa specimens and in corresponding peripheral blood samples of 48 OSCC patients and 26 healthy controls using RT-qPCR. A cutoff point (COP) was determined and a chi-square test (χ² test) was carried out. Survival analysis of PD-L2 and previously reported PD-L1 expression data was performed using Kaplan-Meier analysis (Log-rank test).

RESULTS

PD-L2 expression in tissue samples was significantly (P < 0.001) higher in OSCC patients compared to healthy controls. A significant association of PD-L2 expression above the COP (positive) with malignancy was ascertained (P < 0.001). A significant (P = 0.01) association of previously reported PD-L1 expression rates in peripheral blood with survival could be shown.

CONCLUSION

Peripheral blood PD-L1 expression might be a prognostic marker for OSCC patients and a possible parameter to monitor immune dysfunction in malign diseases. In the peripheral blood, PD-L1 might be more relevant for immune tolerance than PD-L2. Local PD-L2 expression in tissue samples might be useful as a diagnostic parameter for malignancy and could contribute to the immunosuppressive local microenvironment in OSCC.

Galectin 3 expression in regional lymph nodes and lymph node metastases of oral squamous cell carcinomas

BACKGROUND

Neck dissection is standard in surgical management of oral squamous cell carcinomas (oscc). However, the immunologic link between primary tumor and lymph nodes is insufficiently understood. Galectin 3 (Gal3) promotes M2 polarization of macrophages and contributes to immunosuppression. The current study analyzes the association between Gal3 expression in regional lymph nodes of oscc with histomorphologic parameters (T-, N-, L- Pn-stage, grading) of the primary tumor. Additionally, Gal3 expression is correlated with markers of macrophage polarization (M1 vs. M2).

METHODS

Preoperative diagnostic biopsies (n = 26), tumor resection specimens (n = 34), tumor-free lymph nodes (n = 28) and lymph node metastases (n = 10) of T1/T2 oscc patients were immunohistochemically analyzed for Gal3 and macrophage marker (CD68, CD11c, CD163 and MRC1) expression. The number of positive cells and the expression ratios were quantitatively assessed.

RESULTS

High Gal3 expression in tumor-free regional lymph nodes was significantly (p < 0.05) associated with increased tumor size. The epithelial compartment of lymph node metastases showed a significantly (p < 0.05) increased Gal3 expression compared to biopsies and tumor resection specimens. Cell density of M2 macrophages was significantly (p < 0.05) and positively correlated with the number of Gal3 expressing cells in lymph nodes and tumor specimens.

CONCLUSION

Gal3 expression in regional lymph nodes might be associated with oscc progression. The increased Gal3 expression in regional lymph nodes of larger tumors underlines the need of immunomodulatory treatment concepts in early-stage oscc. Blocking of Gal3 might be a therapeutic option in oral cancer.

Galectin 3 expression in primary oral squamous cell carcinomas

Background

Immunologic factors can promote the progression of oral squamous cell carcinomas (oscc). The phylogenetic highly conserved protein Galectin 3 (Gal3) contributes to cell differentiation and immune homeostasis. There is evidence that Gal3 is involved in the progression of oscc and influences the regulation of macrophage polarization. Macrophage polarization (M1 vs. M2) in solid malignancies like oscc contributes to tumor immune-escape. However, the relationship between macrophage polarization and Gal3 expression in oscc is not yet understood. The current study analyzes the association between histomorphologic parameters (T-, N-, L- Pn-status, grading) and Gal3 expression resp. the ratio between Gal3 expressing cells and CD68 positive macrophages in oscc specimens.

Methods

Preoperative diagnostic biopsies (n = 26) and tumor resection specimens (n = 34) of T1/T2 oscc patients were immunohistochemically analyzed for Gal3 and CD68 expression. The number of Gal3 expressing cells and the ratio between CD68 and Gal3 expressing cells was quantitatively assessed.

Results

In biopsy and tumor resection specimens, the number of Gal3 positive cells as well as the Gal3/CD68 ratio were significantly (p < 0.05) higher in T2 oscc compared to T1 cases. In biopsy specimens, a significantly (p < 0.05) increased Gal3 expression and Gal3/CD68 ratio was associated with the progression marker lymph vessel infiltration (L1). Tumor resection specimens of cases with lymph node metastases (N+) had a significantly (p < 0.05) increased Gal3 expression. Additionally, a high Gal3/CD68 ratio correlated significantly (p < 0.05) with higher grading (G3) in tumor resection specimens.

Conclusion

High Gal3 expression in oscc is associated with tumor size (T-status) and parameters of malignancy (N-, L-status, grading). Gal3 might contribute to M2 macrophage mediated local immune tolerance. Gal3 expression shows association with prognosis in oscc and represent a potential therapeutic target.

PD-L1 expression in tumor tissue and peripheral blood of patients with oral squamous cell carcinoma

Background

Immune checkpoints like programmed cell death-1 (PD-1) and its ligand PD-L1 are involved in immune escape mechanisms of solid tumors including oral squamous cell carcinoma (OSCC). Inhibitors of the pathway are successfully used for treating especially advanced disease. However, the physiological relevance of PD-1/PD-L1-signaling in OSCC is insufficiently understood. The aim of the study was to analyze if PD-L1 expression in tumor tissue and peripheral blood samples of OSCC patients is associated with histomorphological tumor parameters and if PD-L1 expression in patients is different from controls.

Results

OSCC tumor specimens showed a significantly higher PD-L1 expression than oral mucosa controls (p < 0.001; upregulation more than 3-fold). Cross-tabulation revealed an association of increased expression of PD-L1 mRNA in tissue specimens with malignancy (p < 0.001).

OSCC cases with higher tumor grade and cases with lymph node metastases (N+) were significantly (p < 0.05) associated with increased PD-L1 expression in peripheral blood. Cross-tabulation revealed an significant association with lymph node metastases (N+) (p ≤ 0.002).

Materials and Methods

PD-L1 mRNA expression was analyzed in tumor specimens and corresponding samples of healthy oral mucosa and peripheral blood of 45 OSCC patients and 36 healthy control persons using RT-qPCR analysis. A Mann-Whitney U-test, a cut-off point analysis and a Chi-square test were carried out.

Conclusions

PD-L1 expression in OSCC could contribute to the immunosuppressive local tumor microenvironment. Increased malignant behavior (higher tumor grade, positive nodal status) might be associated with PD-L1 mediated systemic immune tolerance. Thus, PD-L1 expression in peripheral blood might be an indicator of the existence of metastatic disease (N+) in OSCC.

Macrophage and osteoclast polarization in bisphosphonate associated necrosis and osteoradionecrosis

PURPOSE

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a complication of antiresorptive therapy with nitrogen-containing bisphosphonates (BP). With various suggestions as to pathogenesis, the etiology of BRONJ is not sufficiently understood. Osteoclasts and their precursors, that is, macrophages, are the main target cells of BP. BP can repolarize regeneration- and healing-associated M2 macrophages towards the tissue destructive M1-type. The current study aims to elucidate differences in macrophage and osteoclast polarization in BRONJ, osteoradionecrosis (ORN) and healthy control specimens.

MATERIALS AND METHODS

A total of 39 jaw bone samples (18 BRONJ, 8 ORN and 13 healthy controls) were processed for immunohistochemistry to detect CD68-, CD11c- and CD163-positive cells. Macrophages and osteoclasts were distinguished on the basis of morphological differences. Samples were digitized, and the macrophage and osteoclast cell counts were quantitatively analyzed.

RESULTS

In jaw bone affected by BRONJ, a significantly increased macrophage infiltration and M1 polarization of macrophages can be seen. The density of CD68-expressing osteoclasts is significantly increased in BRONJ specimens compared to ORN and to healthy controls.

CONCLUSIONS

A bisphosphonate-derived shift of macrophage polarization towards M1-polarized macrophages might impair bone tissue homeostasis and thus contribute to the pathogenesis of BRONJ. The observed increase in osteoclast density might be caused by BP-induced prolonged osteoclast survival.

Investigation of the interplay between plasma lipids and macrophage polarization in small oral squamous cell carcinomas with different outcome: A pilot study of 17 cases

INTRODUCTION

Growing evidence suggests a correlation of alternative polarization of macrophages (M2) with a bad outcome of oral cancer. Macrophage polarization plays a significant role in the progression of hyperlipidemia and atherosclerosis, being influenced from plasma cholesterol. On the other hand plasma lipids have been studied epidemiologically as risk factors in carcinogenesis. Goal of our pilot study was the investigation of a possible association of plasma lipids with tumor outcome through their potential influence on macrophage polarization.

MATERIALS AND METHODS

17 patients with small pN0 OSCC with different clinical outcome, treated operatively without postoperative R(C)T constituted our patient collective. Plasma lipids (total cholesterol and triglycerides) were studied in relation to macrophage polarization (determined through the expression of CD68, CD11c, CD163 and MRC1 antibodies) and tumor outcome.

RESULTS

Patients with pathological chronic course of either plasma cholesterol or triglycerides demonstrated an increased infiltration with alternatively polarized macrophages in their specimens. Patients with pathological chronic course of plasma cholesterol showed moreover a bad tumor outcome.

CONCLUSION

A role of plasma lipids in the tumor outcome via alternative macrophage polarization could be assumed. A larger prospective study is needed to confirm our preliminary results.

Prognostic significance of macrophage polarization in early stage oral squamous cell carcinomas

BACKGROUND

Polarization of tumor infiltrating macrophages is associated with the prognosis of solid malignancies and correlates with the occurrence of lymph node metastases in oral squamous cell carcinomas (oscc). Early stage (T1/T2, N0) oscc are characterized by a good prognosis and can be cured by surgery. The postoperative regime usually contains no adjuvant radio-/chemotherapy. The current pilot study was conducted to elucidate whether macrophage polarization in tumor resection specimens and diagnostic biopsies of early stage oscc is associated with tumor outcome.

METHODS

Patients with T1/T2, N0, and R0>5mm oscc without adjuvant therapy and 3-year follow-up after tumor resection were retrospectively selected. Tissue microarrays (TMA) containing diagnostic biopsies (n=17) and tumor resection specimens (n=17) were processed for immunohistochemistry in this pilot study to detect CD68-, CD11c-, CD163- and MRC1-positive macrophages. Samples were digitized, and the expression of macrophage markers was quantitatively analyzed.

RESULTS

High infiltration of M2 polarized macrophages correlated with poor tumor outcome in early stage (T1/T2, N0) oscc. This correlation was observed in tumor resection specimens, but was also observed in diagnostic biopsies. M2 macrophage polarization in biopsies - but not in tumor resection samples - correlated with high scores in tumor grading.

CONCLUSION

Macrophage polarization in early stage oscc is a potential prognostic marker for tumor outcome. The correlation of M2 polarized macrophages with tumor outcome can already be detected in the initial biopsies. Furthermore, M2 polarization of macrophages in biopsies is associated with an increased dedifferentiation.

Macrophage polarisation changes within the time between diagnostic biopsy and tumour resection in oral squamous cell carcinomas--an immunohistochemical study

Background:

The prognosis of solid malignancies has been shown to depend on immunological parameters, such as macrophage polarisation (M1/M2). Recently, it was reported that preoperative oral surgery leads to a worsening of oral squamous cell carcinomas (OSCC) prognosis. Diagnostic incision biopsies are oral surgery procedures that might lead to healing-associated M2 macrophage polarisation with a potential negative influence on tumour biology. No studies have compared macrophage polarisation in OSCC biopsies and tumour specimens.

Methods:

Preoperative diagnostic incision biopsies (n=25) and tumour resection specimens (n=34) of T1/T2 OSCC were processed for immunohistochemistry to detect CD68-, CD11c-, CD163- and MRC1-positive cells. Samples were digitised using whole-slide imaging, and the expression of macrophage markers was quantitatively analysed.

Results:

Carcinoma tissues obtained during OSCC tumour resections showed a significantly (P<0.05) increased CD163 cell count (M2 macrophages) compared with tissues obtained during preoperative incision biopsies. Additionally, the CD163/CD68 ratio (an indicator of M2 polarisation) was significantly (P<0.05) higher in tumour resection specimens than in biopsies.

Conclusions:

This study revealed for the first time an increase in M2 polarisation in samples obtained during OSCC tumour resection surgery compared with preoperative incision biopsies. The biopsy-induced tissue trauma might explain the observed shift in macrophage polarisation towards the tumour-promoting M2 type and could lead to accelerated tumour progression.

Assessment of free microvascular flap perfusion by intraoperative fluorescence angiography in craniomaxillofacial surgery

Microsurgical tissue transfer represents a standard technique for reconstruction in craniomaxillofacial surgery. The transferred tissue is anastomosed to vessels of varying diameters and different physiological conditions. The aim of this study was to evaluate the blood flow in free flaps at their origin and compare this with the flow after reperfusion. In 24 patients undergoing microsurgical procedures (13 radial forearm free flaps (RFFF) and 11 parascapular/scapular free flaps (PSFF)), blood flow was evaluated by intraoperative fluorescence angiography after flap raising and again after reperfusion in the neck area (Flow800, Carl Zeiss AG, Oberkochen, Germany). Flow is expressed by the blood flow index (BFI), maximum intensity (MaxInt) and half-time to MaxInt (t1/2) and was measured in the flap pedicle itself, as well as in the supplying vessels. Following anastomosis of the free flaps in the head and neck area, both the arterial and the venous BFI and MaxInt significantly increased, whereas t1/2 decreased significantly. There was no significant difference in the perfusion parameters between RFFF and PSFF. Intraoperative fluorescence angiography is a reliable method for assessing the perfusion of free microvascular flaps. In the head and neck area, free flaps undergo a significant increase in perfusion but show no differences between varying flap types.

Long-term outcomes after vestibuloplasty with a porcine collagen matrix (Mucograft® ) versus the free gingival graft: a comparative prospective clinical trial

OBJECTIVES

Porcine collagen matrices are proclaimed being a sufficient alternative to autologous free gingival grafts (FGG) in terms of augmenting the keratinized mucosa. The collagen matrix Mucograft^® (CM) already showed a comparable clinical performance in the early healing phase, similar histological appearance, and even a more natural appearance of augmented regions. Predictability for long-term stability does not yet exist due to missing studies reporting of a follow-up >6 months.

MATERIAL AND METHODS

The study included 48 patients with atrophic edentulous or partially edentulous lower jaw situations that had undergone an implant treatment. In the context of implant exposure, a vestibuloplasty was either performed with two FGGs from the palate (n = 21 patients) or with the CM (n = 27 patients). Surgery time was recorded from the first incision to the last suture. Follow-up examinations were performed at the following time points: 10, 30, 90, and 180 days and 1, 2, 3, 4, and 5 years after surgery. The width of keratinized mucosa was measured at the buccal aspect of each implant, and augmented sites were evaluated in terms of their clinical appearances (texture and color).

RESULTS

The groups showed similar healing with increased peri-implant keratinized mucosa after surgery (FGG: 13.06 mm ± 2.26 mm and CM: 12.96 mm ± 2.86 mm). The maximum follow-up was 5 years (5 patients per group). After 180 days, the width of keratinized mucosa had decreased to 67.08 ± 13.85% in the FGG group and 58.88 ± 14.62% in the CM group with no statistically significant difference. The total loss of the width of keratinized mucosa after 5 years was significant between the FGG (40.65%) and the CM group (52.89%). The CM group had significantly shorter operation times than the FGG group. Augmented soft tissues had a comparable clinical appearance to adjacent native gingiva in the CM group. FGGs could still be defined after 5 years.

CONCLUSIONS

The FGG and the CM are both suitable for the regeneration of the peri-implant keratinized mucosa with a sufficient long-term stability. With the CM, tissue harvesting procedures are invalid, surgery time can be reduced, and regenerated tissues have a more esthetic appearance.

Extra-oral defect augmentation using autologous, bovine and equine bone blocks: A preclinical histomorphometrical comparative study

OBJECTIVES

This study aimed to compare autologous bone (AB), bovine bone (BB), and equine bone (EB) blocks with regard to de novo bone formation, connective tissue, and residual bone substitute material portions in a standardized defect animal model.

MATERIAL AND METHODS

In the frontal skull of 20 pigs, 106 standardized cylindrical "critical size defects" were prepared. Defects were randomly filled with AB, BB, and EB blocks. After a healing period of 30 and 60 days, de novo bone formation, residual bone substitute material, and connective tissue portion was assessed by means of histomorphometry (Toluidine blue O staining). Mann-Whitney U-tests were used to evaluate differences between the groups.

RESULTS

The de novo bone formation was significantly higher in the AB group in comparison to the xenogeneic groups (p < 0.05). After 30 days, EB showed significantly (p < 0.05) more newly formed bone compared to the BB group. The soft tissue formation was significantly higher in the BB and EB group. Defects augmented with BB showed significantly (p < 0.05) higher portions of bone substitute materials compared to sides augmented with EB after 30 days.

CONCLUSION

In the extra-oral model, AB blocks were superior concerning de novo bone formation. No clinical advantages of EB blocks could be observed.

Expression of transforming growth factor beta 1-related signaling proteins in irradiated vessels

AIM

Microvascular free tissue transfer is a standard method in head and neck reconstructive surgery. However, previous radiotherapy of the operative region is associated with an increased incidence in postoperative flap-related complications and complete flap loss. As transforming growth factor beta (TGF-β) 1 and galectin-3 are well known markers in the context of fibrosis and lectin-like oxidized low-density lipoprotein 1 (LOX-1) supports vascular atherosclerosis, the aim of this study was to evaluate the expression of TGF-β1 and related markers as well as LOX-1 in irradiated vessels.

MATERIALS AND METHODS

To evaluate the expression of galectin-3, Smad 2/3, TGF-β1, and LOX-1, 20 irradiated and 20 nonirradiated arterial vessels were used for immunohistochemical staining. We semiquantitatively assessed the ratio of stained cells/total number of cells (labeling index).

RESULTS

Expression of galectin-3, Smad 2/3, and TGF-β1 was significantly increased in previously irradiated vessels compared with nonirradiated controls. Furthermore, LOX-1 was expressed significantly higher in irradiated compared with nonirradiated vessels.

CONCLUSION

Fibrosis-related proteins like galectin-3, Smad 2/3, and TGF-β1 are upregulated after radiotherapy and support histopathological changes leading to vasculopathy of the irradiated vessels. Furthermore, postoperative complications in irradiated patients can be explained by increased endothelial dysfunction caused by LOX-1 in previously irradiated patients. Consequently, not only TGF-β1 but also galectin-3 inhibitors may decrease complications after microsurgical tissue transfer.

Increased malignancy of oral squamous cell carcinomas (oscc) is associated with macrophage polarization in regional lymph nodes - an immunohistochemical study

Background

It is largely accepted that specific immunological parameters in solid malignancies are associated with patient’s prognosis. Recently a correlation of macrophage polarization with histomorphological parameters could also be shown in oral squamous cell carcinoma (oscc). The observed tumor derived peripheral immune tolerance could be associated with the macrophage polarization in regional tumor draining lymph nodes.

So far there are no studies analyzing the macrophage polarization in cervical lymph nodes of oscc patients. In the present study we aimed to correlate macrophage polarization in different anatomical lymph node compartments of patients diagnosed with oscc with histopathologic parameters of the primary tumor (T-, N-, L-, V-, Pn-status, grading).

Methods

Tumor free (n = 37) and metastatic (n = 17) lymph nodes of T1 and T2 oscc patients were processed for immunohistochemistry to detect CD68, CD11c, CD163 and MRC1 positive cells. Samples were digitized using whole slide imaging and the number of cells expressing the aforementioned markers in the region of interest quantitatively analyzed.

Results

The malignancy of the primary tumor (defined by T-, L-, Pn-status, grading) correlated with the lymph node macrophage polarization. L1 and Pn1 tumor cases displayed a significantly (p < 0.05) decreased M1 and increased M2 polarization in the sinus of the lymph nodes. G3 cases presented a significantly (p < 0.05) increased M2 polarization in the sinus compared to G2 cases. T2 tumors had significantly (p < 0.05) increased M2 polarization in the interfollicular zone of regional lymph nodes compared to T1 tumors. Metastatic and non-metastatic lymph nodes did not differ regarding their macrophage polarization.

Conclusions

The current study revealed for the first time an influence of oscc on the macrophage polarization in regional lymph nodes. Markers of malignant behavior in the primary tumor were associated with a shift of macrophage polarization in lymph nodes from the anti-tumoral M1 type to the tumor-promoting M2 type. As tumor free and metastatic lymph nodes did not differ in terms of their macrophage polarization pattern, there must be other factors influencing the location for lymph node metastasis formation.

Osteo-radio-necrosis (ORN) and bisphosphonate-related osteonecrosis of the jaws (BRONJ): the histopathological differences under the clinical similarities

OBJECTIVES

Both osteoradionecrosis (ORN) and bisphosphonate associated osteonecrosis of the jaws (BRONJ) present clinically as regions of exposed necrotic bone. The study aimed to demonstrate the histopathological differences behind the observed clinical similarities.

STUDY DESIGN

Ten ORN specimens and ten BRONJ specimens were used, as well as ten samples of normal mandibular bone as control. Two bone-specific stainings were used, i.e. Sirius Red for the study of the relative presence of collagen types I and III and toluidine blue for the study the osteon density.

RESULTS

The Red Green Blue (RGB)-analysis of the specimens stained with Sirius Red identified significant differences between the chromatic patterns observed in bone preparations of patients suffering from ORN when compared to both BRONJ and control samples. Moreover, the osteon density of the BRONJ samples was significantly lower when compared to ORN and normal bone samples.

CONCLUSIONS

The demonstrated differences in the bone architecture and in the bone collagen content between the two pathological conditions most likely reflect underlying pathophysiological differences.

The outcome after surgical therapy of bisphosphonate-associated osteonecrosis of the jaw--results of a clinical case series with an average follow-up of 20 months

OBJECTIVES

The present case series evaluates the success rate of osteotomy and primary wound closure in patients with bisphosphonate-associated osteonecrosis of the jaw (BRONJ).

MATERIALS AND METHODS

Eighty patients suffering from BRONJ were included in the study. All patients received intravenous bisphosphonate therapy and underwent osteotomy and primary wound closure according to a standardised protocol. After discharge, the patients were reviewed on a regular basis over an average time period of 20 months.

RESULTS

During follow-up in 11 patients, a recurrence of BRONJ occurred in the former operation field. Seventeen patients died due to their underlying disease. The success rate of osteotomy and primary wound closure in the treatment of BRONJ was calculated at 84.2 % 20 months after surgery. The results showed non-significant difference concerning the outcome of surgery in the different clinical stages of BRONJ.

CONCLUSIONS

In accordance with previous studies, stage-independent osteotomy and primary wound closure combined with antibiotics shall be deemed a viable treatment option in patients suffering from BRONJ.

CLINICAL RELEVANCE

With a high success rate, osteotomy in combination with primary wound closure seems to be a viable alternative to more conservative protocols in the treatment of BRONJ.

Critical size defect regeneration using PEG-mediated BMP-2 gene delivery and the use of cell occlusive barrier membranes - the osteopromotive principle revisited

OBJECTIVE

The objective of this study was to investigate if osseous regeneration can be accelerated by involvement of periosteal tissue. Bone defect regeneration could be accelerated by the involvement of periosteal tissue if osteogenic cell signalling is maintained within the defect. It was questioned if local cell-mediated BMP-2 gene delivery makes a cell occlusive membrane dispensable during bone critical size defect regeneration.

METHODS

PEG matrix (degradation time 10 days) and PEG membrane (degradation time 120 days) were used in the pig calvarial model. Cylindrical (1 × 1 cm) critical size defects (CSD) (9 per animal; 20 animals) were filled with: (i) particulated autologous bone, covered with PEG membrane (group 1); (ii) HA/TCP, covered with PEG membrane (group 2); (iii) HA/TCP, mixed with PEG matrix (group 3); and (iv) HA/TCP mixed with BMP-2-transfected osteoblasts and PEG matrix (group 4). BMP-2/4 gene transfer: liposomal in vitro transfection of BMP-2/V5-tag fusion-protein. Quantitative histomorphometry (toluidine blue staining) after 2, 4 and 12 weeks assessed bone formation. Semiquantitative immunohistochemistry estimated the expression of BMP-2, V5-tag, Runx-2 and Sox9.

RESULTS

PEG matrix embedded BMP-2 expressing cells presented higher bone formation (P < 0.05) than HA/TCP + PEG matrix defect filling or PEG membrane covering (HA/TCP filling) after 12 weeks. Highest expression of BMP-2, Runx-2 and lowest expression of fibrous tissue marker Sox9 was seen in the BMP-2 group.

CONCLUSION

PEG matrix embedded BMP-2 expressing cells are capable to maintain osteogenic signalling and to accelerate osseous defect regeneration in absence of a cell occlusive membrane.

PEG matrix enables cell-mediated local BMP-2 gene delivery and increased bone formation in a porcine critical size defect model of craniofacial bone regeneration

PURPOSE

This study addressed the suitability of a polyethylene glycol (PEG) matrix as scaffold for cell-mediated local BMP-2 gene transfer in a calvarial critical size defect (CSD) model.

MATERIALS AND METHODS

PEG matrix (degradation time 10 days) and PEG membrane (degradation time 120 days) were used in the pig calvarial model. Cylindrical (1 × 1 cm) CSD (9 per animal; 20 animals) were filled with: (i) HA/TCP, covered by PEG membrane (group 1); (ii) HA/TCP, mixed with PEG matrix (group 2); and (iii) HA/TCP mixed with BMP-2 transfected osteoblasts and PEG matrix (group 3). BMP-2/4 gene transfer: liposomal in vitro transfection of BMP-2/V5-tag fusion-protein. Quantitative histomorphometry (toluidine blue staining) after 2, 4 and 12 weeks assessed bone formation. Semiquantitative immunohistochemistry estimated the expression of BMP-2 and V5-tag.

RESULTS

Group 3 showed significantly higher new bone formation than groups 1, 2 at 4 (P < 0.05) and 12 (P < 0.02) weeks. BMP-2-V5-tag was detected for 4 weeks. BMP-2 expression in group 3 was higher compared to all other groups after 2 and 4 (P < 0.02) weeks.

CONCLUSIONS

The PEG matrix serves as scaffold for cell-mediated BMP-2 gene delivery in guided bone regeneration facilitating cell survival and protein synthesis for at least 4 weeks. Local BMP-2 gene delivery by PEG matrix-embedded cells leads to increased bone formation during critical size defect regeneration.

Increased human defensine levels hint at an inflammatory etiology of bisphosphonate-associated osteonecrosis of the jaw: an immunohistological study

Background

Human β-defensins (hBD) are antimicrobial peptides that are an integral part of bone innate immunity. Recently, it could be shown that expression of hBD-1, -2 and -3 were upregulated in cases of osteomyelitis of the jaws. In order to gain insight into the possible impairment of hBD metabolism in bisphosphonate-associated osteonecrosis of the jaws (BONJ), the present exploratory study was designed so as to determine the qualitative and quantitative expression of afore mentioned hBDs in BONJ and infected osteoradionecrosis (ORN), both of which represent inflammatory bone diseases.

Methods

Bone samples were collected from patients with BONJ (n = 20) and ORN (n = 20). Non-infected healthy bone samples (n = 20) were included as controls. Immunohistological staining in an autostainer was carried out by the (Strept-ABC)-method against hBD-1,-2,-3. Specific positive vs. negative cell reaction of osteocytes (labeling index) near the border of bony resection was determined and counted for quantitative analysis. Number of vital osteocytes vs. empty osteocytes lacunae was compared between groups.

Results

hBD-1,-2 and -3 could be detected in BONJ as well as ORN and healthy bone samples. Immunoreactivity against hBD-2 and -3 was significantly higher in BONJ than in ORN and healthy jaw bone samples. Number of empty osteocyte lacunae was significantly higher in ORN compared with BONJ (P = 0.001).

Conclusion

Under the condition of BONJ an increased expression of hBD-1,-2,-3 is detectable, similarly to the recently described upregulation of defensins in chronically infected jaw bones. It remains still unclear how these findings may relate to the pathoetiology of these diseases and whether this is contributing to the development of BONJ and ORN or simply an after effect of the disease.

Bisphosphonate-associated osteonecrosis of the jaw is linked to suppressed TGFβ1-signaling and increased Galectin-3 expression: a histological study on biopsies

Background

Bisphosphonate associated osteonecrosis of the jaw (BRONJ) implies an impairment in oral hard- and soft tissue repair. An understanding of the signal transduction alterations involved can inform therapeutic strategies. Transforming growth factor β1 (TGFβ1) is a critical regulator of tissue repair; galectin-3 mediates tissue differentiation and specifically modulates periodontopathic bacterial infection. The aim of this study was to compare the expression of TGFβ1-related signaling molecules and Galectin-3 in BRONJ-affected and healthy mucosal tissues. To discriminate between BRONJ-specific impairments in TGFβ1 signaling and secondary inflammatory changes, the results were compared to the expression of TGFβ1 and Galectin-3 in mucosal tissues with osteoradionecrosis.

Methods

Oral mucosal tissue samples with histologically-confirmed BRONJ (n = 20), osteoradionecrosis (n = 20), and no lesions (normal, n = 20) were processed for immunohistochemistry. Automated staining with an alkaline phosphatase-anti-alkaline phosphatase kit was used to detect TGFβ1, Smad-2/3, Smad-7, and Galectin-3. We semiquantitatively assessed the ratio of stained cells/total number of cells (labeling index, Bonferroni-adjustment).

Results

TGFβ1 and Smad-2/3 were significantly decreased (p < 0.032 and p(0.028, respectively) in the BRONJ samples and significantly increased (p < 0.04 and p <0.043, respectively) in the osteoradionecrosis samples compared to normal tissue. Smad-7 was significantly increased (p < 0.031) in the BRONJ group and significantly decreased (p < 0.026) in the osteoradionecrosis group. Galectin-3 staining was significantly (p < 0.025) increased in both the BRONJ and the osteoradionecrosis (p < 0.038) groups compared to the normal tissue group. However, Galectin-3 expression was significantly higher in the BRONJ samples than in the osteoradionecrosis samples (p < 0.044).

Conclusion

Our results showed that disrupted TGFβ1 signaling was associated with delayed periodontal repair in BRONJ samples. The findings also indicated that impairments in TGFβ1-signaling were different in BRONJ compared to osteoradionecrosis. BRONJ appeared to be associated with increased terminal osseous differentiation and decreased soft tissue proliferation. The increase in Galectin-3 reflected the increase in osseous differentiation of mucoperiosteal progenitors, and this might explain the inflammatory anergy observed in BRONJ-affected soft tissues. The results substantiated the clinical success of treating BRONJ with sequestrectomy, followed by strict mucosa closure. BRONJ can be further elucidated by investigating the specific intraoral osteoimmunologic status.

Msx-1 is suppressed in bisphosphonate-exposed jaw bone analysis of bone turnover-related cell signalling after bisphosphonate treatment

OBJECTIVES

Bone-destructive disease treatments include bisphosphonates and antibodies against receptor activator for nuclear factor κB ligand (aRANKL). Osteonecrosis of the jaw (ONJ) is a side-effect. Aetiopathology models failed to explain their restriction to the jaw. The osteoproliferative transcription factor Msx-1 is expressed constitutively only in mature jaw bone. Msx-1 expression might be impaired in bisphosphonate-related ONJ. This study compared the expression of Msx-1, Bone Morphogenetic Protein (BMP)-2 and RANKL, in ONJ-affected and healthy jaw bone.

MATERIAL AND METHODS

An automated immunohistochemistry-based alkaline phosphatase-anti-alkaline phosphatase method was used on ONJ-affected and healthy jaw bone samples (n = 20 each): cell-number ratio (labelling index, Bonferroni adjustment). Real-time RT-PCR was performed to quantitatively compare Msx-1, BMP-2, RANKL and GAPDH mRNA levels.

RESULTS

Labelling indices were significantly lower for Msx-1 (P < 0.03) and RANKL (P < 0.003) and significantly higher (P < 0.02) for BMP-2 in ONJ compared with healthy bone. Expression was sevenfold lower (P < 0.03) for Msx-1, 22-fold lower (P < 0.001) for RANKL and eightfold higher (P < 0.02) for BMP-2 in ONJ bone.

CONCLUSIONS

Msx-1, RANKL suppression and BMP-2 induction were consistent with the bisphosphonate-associated osteopetrosis and impaired bone remodelling in BP- and aRANKL-induced ONJ. Msx-1 suppression suggested a possible explanation of the exclusivity of ONJ in jaw bone. Functional analyses of Msx-1- RANKL interaction during bone remodelling should be performed in the future.

Expression of Msx-1 is suppressed in bisphosphonate associated osteonecrosis related jaw tissue-etiopathology considerations respecting jaw developmental biology-related unique features

Background

Bone-destructive disease treatments include bisphosphonates and antibodies against the osteoclast differentiator, RANKL (aRANKL); however, osteonecrosis of the jaw (ONJ) is a frequent side-effect. Current models fail to explain the restriction of bisphosphonate (BP)-related and denosumab (anti-RANKL antibody)-related ONJ to jaws. Msx-1 is exclusively expressed in craniofacial structures and pivotal to cranial neural crest (CNC)-derived periodontal tissue remodeling. We hypothesised that Msx-1 expression might be impaired in bisphosphonate-related ONJ. The study aim was to elucidate Msx-1 and RANKL-associated signal transduction (BMP-2/4, RANKL) in ONJ-altered and healthy periodontal tissue.

Methods

Twenty ONJ and twenty non-BP exposed periodontal samples were processed for RT-PCR and immunohistochemistry. An automated staining-based alkaline phosphatase-anti-alkaline phosphatase method was used to measure the stained cells:total cell-number ratio (labelling index, Bonferroni adjustment). Real-time RT-PCR was performed on ONJ-affected and healthy jaw periodontal samples (n = 20 each) to quantitatively compare Msx-1, BMP-2, RANKL, and GAPDH mRNA levels.

Results

Semi-quantitative assessment of the ratio of stained cells showed decreased Msx-1 and RANKL and increased BMP-2/4 (all p < 0.05) expression in ONJ-adjacent periodontal tissue. ONJ tissue also exhibited decreased relative gene expression for Msx-1 (p < 0.03) and RANKL (p < 0.03) and increased BMP-2/4 expression (p < 0.02) compared to control.

Conclusions

These results explain the sclerotic and osteopetrotic changes of periodontal tissue following BP application and substantiate clinical findings of BP-related impaired remodeling specific to periodontal tissue. RANKL suppression substantiated the clinical finding of impaired bone remodelling in BP- and aRANKL-induced ONJ-affected bone structures. Msx-1 suppression in ONJ-adjacent periodontal tissue suggested a bisphosphonate-related impairment in cellular differentiation that occurred exclusively jaw remodelling. Further research on developmental biology-related unique features of jaw bone structures will help to elucidate pathologies restricted to maxillofacial tissue.

Skin repair using a porcine collagen I/III membrane--vascularization and epithelization properties

BACKGROUND

Collagen membranes have been developed to overcome the problem of limited availability of skin grafts. Vascularization and restricted functional epithelization limit the success of bioartificial constructs.

OBJECTIVE

To compare the vascularization, epithelization, and integration of a porcine collagen I/III membrane with that of split-thickness skin grafts on skin wounds.

MATERIALS AND METHODS

In 21 adult pigs, full-thickness skin defects on the rear side of the ear healed by split-thickness skin grafting, by covering with the membrane, or by free granulation. Skin samples on postoperative days 1, 3, 7, 14, 21, and 28 were evaluated histologically (hematoxylin-eosin, Sirius Red) and using immunohistochemistry (cytokeratin 5/6, transforming growth factor beta receptor (TGFbetaR-III) and immunoblot (TGFbeta(1,3), Smad2/3). Epithelial thickness and TGFbetaR-III-positive capillary area were quantitatively assessed.

RESULTS

Epithelization and vascularization in the membrane group were not significantly different from in the group treated with a split-thickness skin graft. Free granulation showed significantly slower epithelization and vascularization (p<.05). TGFbeta(1) and Smad2/3 complex expression were high during free granulation. Matrix was distinguishable until day 7.

CONCLUSIONS

This membrane serves as a suitable full-thickness dermal substitute, because the membrane is vascularized faster than free granulation tissue and enables early epithelization.