Porcine bone scaffolds adsorb growth factors secreted by MSCs and improve bone tissue repair

An ideal tissue-engineered bone graft should have both excellent pro-osteogenesis and pro-angiogenesis properties to rapidly realize the bone regeneration in vivo . To meet this goal, in this work a porcine bone scaffold was successfully used as a Trojan horse to store growth factors produced by mesenchymal stem cells (MSCs). This new scaffold showed a time-dependent release of bioactive growth factors, such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), in vitro . The biological effect of the growth factors-adsorbed scaffold on the in vitro commitment of MSCs into osteogenic and endothelial cell phenotypes has been evaluated. In addition, we have investigated the activity of growth factor-impregnated granules in the repair of critical-size defects in rat calvaria by means of histological, immunohistochemical, and molecular biology analyses. Based on the results of our work bone tissue formation and markers for bone and vascularization were significantly increased by the growth factor-enriched bone granules after implantation. This suggests that the controlled release of active growth factors from porcine bone granules can enhance and promote bone regeneratio

Biocompatibility and antibacterial properties of zirconium nitride coating on titanium abutments: An in vitro study

Improving soft tissue attachment and reducing bacterial colonization on titanium abutments are key factors for the long-term maintenance of healthy soft and hard peri-implant tissues. This in vitro study was conducted to compare the biocompatibility and antibacterial activity of four different surfaces: uncoated Ti6Al4V, anodized, and coated with titanium nitride or zirconium nitride. Surface topography was investigated with a high-resolution system for measuring surface finishes. Human gingival fibroblast (HGF) adhesion and proliferation were examined using MTT assay, Scanning Electron Microscopy (SEM) imaging, immunofluorescence analysis and real-time PCR for selected target genes. The hemolysis and AMES tests were performed to assess the chemical compounds' blood compatibility and mutagenic potential, respectively. Antibacterial activity was tested against five bacterial strains isolated from the oral cavity (Streptococcus salivarius, S. sanguinis, S. mutans, S. sobrinus, S. oralis), and the percentage of dead bacteria was calculated. Roughness measurements confirmed a substantial similarity between the surfaces and their compatibility with clinical applications. MTT assay, SEM analysis and immunofluorescence staining showed adhesion and proliferation of HGFs cultured on all the examined surfaces. PCR confirmed that HGFs produced extracellular matrix components efficiently on all the surfaces. No hemolytic activity was detected, and the AMES test confirmed the surfaces' clinical safety. For all tested bacterial strains, biofilms grown on the zirconium nitride surface showed a higher percentage of dead bacteria than on the other disks. The titanium nitride surface inactivated bacterial biofilms, too, but to a lesser extent

Genetical stability and osteogenic ability of mesenchimal stem cells on demineralized bone matrices

Journal of Osseointegration Volume 7, Issue 1, 1 March 2015, Pages 2-7 Open Access Genetical stability and osteogenic ability of mesenchimal stem cells on demineralized bone matrices (Article) Pozzuoli, A.a, Gardin, C.b, Aldegheri, R.a, Bressan, E.c, Isola, M.d, Calvo-Guirado, J.L.e, Biz, C.a, Arrigoni, P.a, Feroni, L.b, Zavan, B.b a Department of Surgical,Oncological and Gastroenterological Sciences, University of Padua, Padua, Italy b Department of Biomedical Sciences, University of Padua, Padua, Italy c Department of Neurosciences, University of Padua, Padua, Italy d Department of Animal Medicine, Production and Health (MAPS), Italy e Department of General Dentistry, Faculty of Medicine and Dentistry, University of Murcia, Murcia, Spain Hide additional affiliations View references (44) Abstract Aim: Tissue engineering is a rapidly expanding field with regard to the use of biomaterials and stem cells in the orthopedic surgery. Many experimental studies have been done to understand the best characteristics of cells, materials and laboratory methods for safe clinical applications. The aim of this study was to compare the ability of 2 different human demineralized bone matrices (DBMs), the one enriched and the other not enriched with hyaluronic acid, to stimulate in vitro the proliferation and the osteogenic differentiation of human adipose-derived stem cells (ADSCs) seeded onto an osteoconductive scaffold. Materials and Methods: ADSCs were isolated, by enzymatic digestion, from abdominal adipose tissue of 5 patients undergoing cosmetic lipoaspiration surgery. ADSCs were then seeded onto a 3D scaffold in the presence of the two different osteoinductive matrices of human demineralized bone and evaluated for proliferation and osteogenic differentiation. The safety of the methods was verified using array-Comparative Genomic Hybridization (array-CGH). Results: ADSCs were able to differentiate in osteogenic sense. Both DBMs showed the ability to induce osteogenic differentiation of the cells. Conclusion: array-CGH showed no changes at genome level, thus confirming the safety of materials and method

The biological properties of OGI surfaces positively act on osteogenic and angiogenic commitment of mesenchymal stem cells

Osteogenesis process displays a fundamental role during dental implant osteointegration. In the present work, we studied the influence of Osteon Growth Induction (OGI) surface properties on the angiogenic and osteogenic behaviors of Mesenchymal Stem cells (MSC). MSC derived from dental pulp and HUVEC (Human Umbilical Vein Endothelial Cells) were grown in on OGI titanium surfaces, and cell proliferation and DNA synthesis were evaluated by MTT [3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide] test and DNA quantification. Gene expression has been performed in order to evaluate the presence of mRNA related to endothelial and osteogenesis markers. Moreover, morphological and biochemical analyses of osteogenesis commitments has been performed. On OGI surfaces, MSC and HUVEC are able to proliferate. Gene expression profiler confirms that MSC on OGI surfaces are able to express endothelial and osteogenic markers, and that these expression are higher compared the expression on control surfaces. In conclusion On OGI surfaces proliferation, expression and morphological analyses of angiogenesis-associated markers in MSC are promoted. This process induces an increasing on their osteogenesis commitmen

Plasma rich in growth factors in human extraction sockets: a radiographic and histomorphometric study on early bone deposition

Objectives To determine whether and to what extent the additional application of plasma rich in growth factors ( PRGF ) to an extraction socket may influence the early bone deposition, as assessed by micro‐computed tomography (micro‐ CT ) scan as well as histomorphometric markers. Material and methods Twenty‐eight patients (age range: 34–74 years) contributing 36 extraction sockets were included in the study. Sockets were either treated with PRGF ( PRGF group; 18 sites in 11 patients) or left to spontaneous healing (control group; 18 sites in 17 patients). Radiographic and histomorphometric analysis was performed on bone cores trephined from each healing socket after 4–6 (T1) or 7–10 (T2) weeks of healing. Results Patients treated with PRGF application showed (i) similar bone volume and tissue mineral content, (ii) a trend, although not statistically significant, toward a greater number of CD 68+ cells (at T 1 and T 2) and v VW + cells (at T1), and (iii) a similar OCN staining score throughout the study, when compared with control group. Conclusions Plasma rich in growth factors‐treated group did not show any enhancement in early (4 and 8 weeks) bone deposition compared with control group.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/100296/1/clr12033.pd

Decellularization and Delipidation Protocols of Bovine Bone and Pericardium for Bone Grafting and Guided Bone Regeneration Procedures

The combination of bone grafting materials with guided bone regeneration (GBR) membranes seems to provide promising results to restore bone defects in dental clinical practice. In the first part of this work, a novel protocol for decellularization and delipidation of bovine bone, based on multiple steps of thermal shock, washes with detergent and dehydration with alcohol, is described. This protocol is more effective in removal of cellular materials, and shows superior biocompatibility compared to other three methods tested in this study. Furthermore, histological and morphological analyses confirm the maintenance of an intact bone extracellular matrix (ECM). In vitro and in vivo experiments evidence osteoinductive and osteoconductive properties of the produced scaffold, respectively. In the second part of this study, two methods of bovine pericardium decellularization are compared. The osmotic shock-based protocol gives better results in terms of removal of cell components, biocompatibility, maintenance of native ECM structure, and host tissue reaction, in respect to the freeze/thaw method. Overall, the results of this study demonstrate the characterization of a novel protocol for the decellularization of bovine bone to be used as bone graft, and the acquisition of a method to produce a pericardium membrane suitable for GBR applications

Platform switching on wide-diameter external hex implants a finite element analysis

Objectives: The objective of this work was to use finite element analysis to compare the effect of forces coming to bear on abutments 4.1 or 5.0 mm in diameter connected to a 5.0 mm implant (i.e. with or without platform swit - ching). Study design: A 3D CAD model of a 5 x 11.5 mm external hex implant was developed, complete with a connection screw and either of two abutments, one 4.1 and the other 5 mm in diameter, to assess the influence of two loading conditions, i.e. 200 N loaded either axially or off center on the top of the abutment. Results and conclusions: In the symmetrically loaded models, greater stresses were transmitted to the bone in the area below the neck of the implant in the case of the wider-diameter abutment. When the narrower abutment was considered, the stress lines remained confined to the metal and were transferred to the bone in a more distal position. When the stresses in the bone where compared under non-symmetrical loading of the larger- and smaller-diameter abutments, the stresses reached lower values in the latter case. These findings indicate that platform switching (i.e. coupling a 4.1 mm abutment with a 5 mm implant) achieves a better, more even distribution of the peri-implant stresses deriving from simulated occlusal loads on the bone margins

Applications of videolaparoscopic surgery in children

OBJECTIVES: to present the videolaparoscopies performed by the Children's Surgery Service, and study the main indications for pediatric laparoscopic surgeries, considering advantages and disadvantages over conventional open procedures. METHODS: retrospective analysis of 612 videolaparoscopies in children aged between 8 days and 17 years treated from November/95 to 2000. Basic principles of videolaparoscopy and the postoperative management of several pediatric diseases are described. The results, advantages, and complications were analyzed after a 5-year follow-up period. RESULTS:laparoscopic surgery allowed for a wide series of abdominal procedures conventionally carried out through open surgery, mainly for the treatment of gastroesophageal reflux disease, inflammatory acute abdomen, adhesive intestinal obstruction, biliary lithiasis, tumors, cryptorchidism, ovarian diseases, splenectomies, aganglionosis, trauma and others. Morbidity was low (1%), and mortality due to laparoscopy was nonexistent. Conversion to laparotomy occurred in only 14 cases (2.3%), mainly because of trauma. The principal advantages included minimal surgical trauma, pain and reflex ileum, short hospital stay, almost no incisional hernias and better cosmetic scars. CONCLUSIONS: videolaparoscopy seems to be a great advance in modern pediatric surgery, allowing safer and less invasive treatment of a wide series of abdominal diseases at all pediatric ages.OBJETIVO: apresentar a casuística de videolaparoscopias do serviço, analisando as principais indicações para operações videolaparoscópicas em pediatria e considerando as vantagens e desvantagens em relação aos procedimentos convencionais por laparotomia. MÉTODOS: análise retrospectiva de 612 videolaparoscopias em crianças com idades de 8 dias a 17 anos, operadas de novembro/1995 a 2000. São descritos os princípios básicos da videolaparoscopia e o manejo pós-operatório nas inúmeras indicações pediátricas. Os resultados, vantagens e complicações foram analisados após um período de seguimento de até 5 anos. RESULTADOS: a cirurgia laparoscópica permitiu realizar vários procedimentos abdominais convencionalmente efetuados por via aberta, sobretudo no tratamento do refluxo gastroesofágico, abdome agudo inflamatório, criptorquidia, obstrução por bridas, litíase biliar, tumores, afecções de ovário, esplenectomia, aganglionose, trauma e outros. A morbidade foi baixa (1%) e a mortalidade devido à laparoscopia foi nula. Houve conversão para laparotomia em somente 14 casos (2,3%), sobretudo em trauma. As principais vantagens incluíram mínimos trauma cirúrgico, dor e íleo paralítico, pouco tempo de internação, quase ausência de hérnia incisional e melhor estética. CONCLUSÕES: a videolaparoscopia parece ser um grande avanço da cirurgia pediátrica moderna, permitindo tratar de modo menos invasivo e com segurança grande parte das afecções abdominais em crianças de todas as idades.Universidade Federal de São Paulo (UNIFESP)UFGInstituto Ortopédico de Goiânia e no Hospital AmparoUNIFESPSciEL

Assessment of pulse arrival time effects in a trivariate cardiovascular model on diagnostic indexes in the ICU

LAUREA MAGISTRALEIl Sistema Nervoso Autonomo (SNA) regola vari processi fisiologici, inclusi segnali cardiovascolari come la frequenza cardiaca (HR) e la pressione sanguigna (BP). Molti modelli matematici come WindKessel e gli Autoregressivi Multivariati sono stati usati per stimare questi segnali e le loro relazioni. Utilizzando un modello Point Process, questo lavoro di tesi vuole valutare gli effetti di una terza covariata, il Pulse Arrival Time (PAT), su misure autonomiche di rilievo che potrebbero essere influenzate dalla vasoattività. Quindi, il lavoro di tesi è stato svolto su 4 fasi: 1. adattamento degli indici spettrali come i gain direzionali e le coerenze ad un framework trivariato; 2. validazione dei nuovi indici trivariati su dati simulati; 3. validazione dei nuovi indici su registrazioni di tilt table test, valutando la presenza di nuovi andamenti legati al PAT; 4. valutazione dei nuovi indici trivariati in contesto clinico di terapia intensiva, con particolare attenzione alla caratterizzazione della sepsi. Partendo dalla prima fase di definizione un modello trivariato, per valutarne la capacità di identificare proprietà spettrali tempo-varianti è stato testato su segnali simulati con cambi predefiniti di ampiezza e fase nel tempo: gain e fasi direzionali hanno identificato adeguatamente i cambiamenti imposti. A seguire, il nuovo modello è stato usato su dati reali da tilt table test. Gli indici trivariati hanno mantenuto la capacità discriminativa dei loro analoghi bivariati, come accertato dal signed rank test sulla mediana delle fasi tilt contro la mediana delle fasi rest; però, grafici dell'andamento temporale mediano degli indici spettrali trivariati durante i protocolli di tilt hanno mostrato pattern interessanti che potrebbero essere legati alla vasoattività. Applicando il modello ai dati dei pazienti settici in terapia intensiva, alcuni dei risultati trivariati sono associabili allo stato deteriorato della vascolatura e alla risposta autonomica depressa nella sepsi. In conclusione, l'aggiunta di una terza covariata PAT sembra aver portato alla luce lo stato della vascolatura e degli effetti esterni che la influenzano (che siano meccanici, autonomici o patologici). Nella letteratura analizzata, pochi paper riportano l'uso di modelli statistici black-box per quantificare o analizzare l'attività vascolare di per sé. L'apporto più rilevante della nostro progetto di tesi, è quello di essere il primo ad usare un modello trivariato che include PAT per caratterizzare la sepsi in un contesto di terapia intensiva.The Autonomic Nervous System (ANS) regulates several physiological processes, including cardiovascular signals such as Heart Rate (HR) and Blood Pressure (BP). Several mathematical models such as WindKessel and Multivariate Autoregressive Models have been used to try to estimate these signals and their relations. Within a Point Process framework, this thesis work aimed at investigating the effects of a third covariate, the Pulse Arrival Time (PAT), on autonomic measures of interest that might be affected by vasoactivity. To this end, the thesis work has been developed in 4 phases: 1. adaptation of spectral indexes such as directional gains and coherences to a trivariate framework; 2. validation of the new trivariate indexes on surrogate data; 3. validation of the new indexes on tilt table test recordings, while evaluating new PAT related behaviours; 4. assessment of trivariate indexes in an ICU clinical context, with a focus on sepsis characterization. Starting from the first step of the definition of the new trivariate model, time-varying simulated signals with pre-defined amplitude and phase changes were used to assess its ability to identify time-varying spectral properties: the new trivariate directional gains and phases indeed identified and correctly quantified the imposed changes. Then, the new model has been used on real data from a tilt table test. The trivariate indexes kept the discriminative power of their bivariate analogues, as assessed by signed rank test on the median of tilt phases against the median of rest phases; though, plots of the trivariate median spectral indexes during tilt protocols showed interesting patterns that might be related to vasoactivity. When the model is applied to ICU sepsis recordings, the trivariate indexes results agree with the deteriorated state of the vasculature and general autonomic impairment in sepsis. In the end, the addition of PAT as a third covariate helped shed light on the state of the vasculature and provided an assessment of the influences of mechanical, autonomic or pathological nature acting on it. From the available literature, only a few papers used statistical black-box models to quantify or provide insights on vascular activity by itself. Importantly, our study was the first to use a trivariate framework including PAT to characterize Sepsis in ICU pathological data