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Background: Culicoides biting midges transmit viruses resulting in disease in ruminants and equids such as bluetongue, Schmallenberg disease and African horse sickness. In the past decades, these diseases have led to important economic losses for farmers in Europe. Vector abundance is a key factor in determining the risk of vector-borne disease spread and it is, therefore, important to predict the abundance of Culicoides species involved in the transmission of these pathogens. The objectives of this study were to model and map the monthly abundances of Culicoides in Europe. Methods: We obtained entomological data from 904 farms in nine European countries (Spain, France, Germany, Switzerland, Austria, Poland, Denmark, Sweden and Norway) from 2007 to 2013. Using environmental and climatic predictors from satellite imagery and the machine learning technique Random Forests, we predicted the monthly average abundance at a 1 km2 resolution. We used independent test sets for validation and to assess model performance. Results: The predictive power of the resulting models varied according to month and the Culicoides species/ensembles predicted. Model performance was lower for winter months. Performance was higher for the Obsoletus ensemble, followed by the Pulicaris ensemble, while the model for Culicoides imicola showed a poor performance. Distribution and abundance patterns corresponded well with the known distributions in Europe. The Random Forests model approach was able to distinguish differences in abundance between countries but was not able to predict vector abundance at individual farm level. Conclusions: The models and maps presented here represent an initial attempt to capture large scale geographical and temporal variations in Culicoides abundance. The models are a first step towards producing abundance inputs for R0 modelling of Culicoides-borne infections at a continental scale.

Objectives: The aim of the present study was to characterize the cellular reaction to a xenogeneic resorbable collagen membrane of porcine origin using a subcutaneous implantation model in Wistar rats over 30 days. Materials and methods: Ex vivo, liquid platelet-rich fibrin (PRF), a leukocyte and platelet-rich cell suspension, was used to evaluate the blood cell membrane interaction. The material was implanted subcutaneously in rats. Sham-operated rats without biomaterial displayed physiological wound healing (control group). Histological, immunohistological, and histomorphometric analyses were focused on the inflammatory pattern, vascularization rate, and degradation pattern. Results: The membrane induced a large number of mononuclear cells over the observation period, including lymphocytes, macrophages, and fibroblasts. After 15 days, multinucleated giant cells (MNGCs) were observed on the biomaterial surface. Their number increased significantly, and they proceeded to the center of the biomaterial on day 30. These cells highly expressed CD-68, calcitonin receptor, and MMP-9, but not TRAP or integrin-ß3. Thus, the membrane lost its integrity and underwent disintegration as a consequence of the induction of MNGCs. The significant increase in MNGC number correlated with a high rate of vascularization, which was significantly higher than the control group. Physiological wound healing in the control group did not induce any MNGCs at any time point. Ex vivo blood cells from liquid-PRF did not penetrate the membrane. Conclusion: The present study suggests a potential role for MNGCs in biomaterial degradation and questions whether it is beneficial to accept them in clinically approved biomaterials or focus on biomaterials that induce only mononuclear cells. Thus, further studies are necessary to identify the function of biomaterial-induced MNGCs. Clinical relevance: Understanding the cellular reaction to biomaterials is essential to assess their suitability for specific

Platelet-rich fibrin (PRF) is a blood concentrate derived from venous blood that is processed without anticoagulants by a one-step centrifugation process. This three-dimensional scaffold contains inflammatory cells and plasma proteins entrapped in a fibrin matrix. Liquid-PRF was developed based on the previously described low-speed centrifuge concept (LSCC), which allowed the introduction of a liquid-PRF formulation of fibrinogen and thrombin prior to its conversion to fibrin. Liquid-PRF was introduced to meet the clinical demand for combination with biomaterials in a clinically applicable and easy-to-use way. The aim of the present study was to evaluate, ex vivo, the interaction of the liquid-PRF constituents with five different collagen biomaterials by histological analyses. The results first demonstrated that large variability existed between the biomaterials investigated. Liquid-PRF was able to completely invade Mucograft® (MG; Geistlich Biomaterials, Wolhusen, Switzerland) and to partly invade Bio-Gide® (BG; Geistlich Biomaterials, Wolhusen, Switzerland) and Mucoderm® (MD; Botiss Biomaterials, Berlin, Germany), and Collprotect® (CP; Botiss Biomaterials, Berlin, Germany) showed only a superficial interaction. The BEGO® collagen membrane (BCM; BEGO Implant Systems) appeared to be completely free of liquid-PRF. These results were confirmed by the different cellular penetration and liquid-PRF absorption coefficient (PAC) values of the evaluated membranes. The present study demonstrates a system for loading biomaterials with a complex autologous cell system (liquid-PRF) in a relatively short period of time and in a clinically relevant manner. The combination of biomaterials with liquid-PRF may be clinically utilized to enhance the bioactivity of collagen-based biomaterials and may act as a biomaterial-based growth factor delivery system.

The present study evaluated the tissue response toward a resorbable collagen membrane derived from bovine achilles tendon (test group) in comparison to physiological wound healing (control group). After subcutaneous implantation in Wistar rats over 30 days, histochemical and immunohistochemical methods elucidated the cellular inflammatory response, vascularization pattern, membrane protein and cell absorbance capacity. After 30 days, the test-group induced two different inflammatory patterns. On the membrane surface, multinucleated giant cells (MNGCs) were formed after the accumulation of CD-68-positive cells (macrophages), whereas only mononuclear cells (MNCs) were found within the membrane central region. Peri-implant vascularization was significantly enhanced after the formation of MNGCs. No vessels were found within the central region of the membrane. Physiological wound healing revealed no MNGCs at any time point. These dynamic changes in the cellular reaction and vascularization within the test-group are related typical indications of a foreign body reaction. Due to the membrane-specific porosity, mononuclear cells migrated into the central region, and the membrane maintained its integrity over 30 days by showing no breakdown or disintegration. The ex vivo investigation analyzed the interaction between the membrane and a blood concentrate system, liquid platelet-rich fibrin (liquid PRF), derived from human peripheral blood and consisting of platelets, leukocytes and fibrin. PRF penetrated the membrane after just 15 min. The data question the role of biomaterial-induced MNGCs as a pathological reaction and whether this is acceptable to trigger vascularization or should be considered as an adverse reaction. Therefore, further pre-clinical and clinical studies are needed to identify the types of MNGCs that are induced by clinically approved biomaterials.

Titanium is a biocompatible material that is frequently used for making implantable medical devices. Nanoengineering of the surface is the common method for increasing material biocompatibility, and while the nanostructured materials are well-known to represent attractive substrata for eukaryotic cells, very little information has been documented about the interaction between mammalian cells and bactericidal nanostructured surfaces. In this study, we investigated the effect of bactericidal titanium nanostructures on PC12 cell attachment and differentiation—a cell line which has become a widely used in vitro model to study neuronal differentiation. The effects of the nanostructures on the cells were then compared to effects observed when the cells were placed in contact with non-structured titanium. It was found that bactericidal nanostructured surfaces enhanced the attachment of neuron-like cells. In addition, the PC12 cells were able to differentiate on nanostructured surfaces, while the cells on non-structured surfaces were not able to do so. These promising results demonstrate the potential application of bactericidal nanostructured surfaces in biomedical applications such as cochlear and neuronal implants.

Biomaterials are widely used in guided bone regeneration (GBR) and guided tissue regeneration (GTR). After application, there is an interaction between the host immune system and the implanted biomaterial, leading to a biomaterial-specific cellular reaction. The present review focuses on cellular reactions to numerous biomaterials in vivo with consideration of different implantation models and microenvironments in different species, such as subcutaneous implantation in mice and rats, a muscle model in goats and a femur model in rabbits. Additionally, cellular reactions to different biomaterials in various clinical indications within the oro-maxillofacial surgical field were considered. Two types of cellular reactions were observed. There was a physiological reaction with the induction of only mononuclear cells and a pathological reaction with the induction of multinucleated giant cells (MNGCs). Attention was directed to the frequently observed MNGCs and consequences of their appearance within the implantation region. MNGCs have different subtypes. Therefore, the present review addresses the different morphological phenotypes observed within the biomaterial implantation bed and discusses the critical role of MNGCs, their subtypes and their precursors as well as comparing the characteristics and differences between biomaterial-related MNGCs and osteoclasts. Polymeric biomaterials that only induced mononuclear cells underwent integration and maintained their integrity, while polymeric biomaterials that induced MNGCs underwent disintegration with material breakdown and loss of integrity. Hence, there is a question regarding whether our attention should be directed to alternative biological concepts, in combination with biomaterials that induce a physiological mononuclear cellular reaction to optimize biomaterial-based tissue regeneration.

Objective: To investigate the relationship between tumor-associated macrophages (TAMs), neovascularization, and tumor cell migration in oral squamous cell carcinoma (OSCC) of an African subpopulation. Materials and Methods: Twenty OSCC paraffin blocks underwent immunohistochemistry to TAM1 (CCR7), TAM2 (CD206), Twist, E-cadherin, N-cadherin, and CD34. The relative percentage of CCR7 + and CD206 + cells to overall immune cell population was calculated for three high power fields and an average was taken. TAM-related microvessel density (MVD) was determined as the mean of the three recorded values. Cases that had no CD34 + vessels adjacent to the TAMs region were regarded as having an MVD score of 0. Results: Ten cases (50%) expressed greater CCR7 activity than CD206, seven cases (35%) expressed approximately equal activity of CCR7 and CD206, while three cases (15%) expressed greater activity of CD206 than CCR7. Twist expression was strong in some cases with strong N-cadherin and weak E-cadherin, but the expression of Twist was not consistently high in all cases that expressed strong N-cadherin and weak E-cadherin. Conclusions: TAMs distribution suggested antitumor activity and the potential for tumor metastasis was only partly due to Twist-mediated epithelial–mesenchymal transition., Objectif: Étudier la relation entre les macrophages associés à la tumeur (TAM), la néovascularisation et la migration des cellules tumorales dans le carcinome épidermoïde oral (OSCC) d'une sous-population africaine. Matériaux et méthodes: Vingt blocs de paraffines OSCC ont subi une immunohistochimie à TAM1 (CCR7), TAM2 (CD206), Twist, E-cadhérine, N-cadhérine et CD34. Le pourcentage relatif de cellules CCR7+ et CD206+ dans la population globale de cellules immunitaires a été calculé pour 3 champs de puissance élevée et une moyenne prise. La densité de microvaisseaux (MVD) liée aux TAM a été déterminée comme la moyenne des trois valeurs enregistrées. Les cas qui n'avaient pas de navires CD34+ adjacents à la région des TAM étaient considérés comme ayant un score MVD de 0. Résultats: Dix cas (50%) ont exprimé une plus grande activité CCR7 que CD206, 7 cases (35%) ont exprimé une activité approximativement égale de CCR7 et CD206, tandis que 3 cas (15%) ont exprimé une plus grande activité de CD206 que CCR7. L'expression de la Twist était forte dans certains cas avec une N-cadhérine forte et une E-cadhérine faible, mais l'expression de la Twist n'était pas toujours élevée dans tous les cas, ce qui exprimait une N-cadhérine forte et une E-cadhérine faible. Conclusions: La distribution des TAM a suggéré une activité antitumorale et le potentiel de métastases tumorales était seulement dû à l'EMT à effet de Twist.

Cellular attachment plays a vital role in the differentiation of pheochromocytoma (PC12) cells. PC12 cells are noradrenergic clonal cells isolated from the adrenal medulla of Rattus norvegicus and studied extensively as they have the ability to differentiate into sympathetic neuron-like cells. The effect of several experimental parameters including (i) the concentration of nerve growth factor (NGF); (ii) substratum coatings, such as poly-L-lysine (PLL), fibronectin (Fn), and laminin (Lam); and (iii) double coatings composed of PLL/Lam and PLL/Fn on the differentiation process of PC12 cells were studied. Cell morphology was visualised using brightfield phase contrast microscopy, cellular metabolism and proliferation were quantified using a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay, and the neurite outgrowth and axonal generation of the PC12 cells were evaluated using wide field fluorescence microscopy. It was found that double coatings of PLL/Lam and PLL/Fn supported robust adhesion and a two-fold enhanced neurite outgrowth of PC12 cells when treated with 100 ng/mL of NGF while exhibiting stable metabolic activity, leading to the accelerated generation of axons.