Mineralized collagen plywood contributes to bone autograft performance.

Autologous bone (AB) is the gold standard for bone-replacement surgeries, despite its limited availability and the need for an extra surgical site. Traditionally, competitive biomaterials for bone repair have focused on mimicking the mineral aspect of bone, as evidenced by the widespread clinical use of bioactive ceramics. However, AB also exhibits hierarchical organic structures that might substantially affect bone regeneration.

Periodontal reconstruction by heparan sulfate mimetic-based matrix therapy in -infected mice.

Background: Periodontitis is a set of chronic inflammatory diseases affecting the supporting structures of the teeth, during which a persistent release of lytic enzymes and inflammatory mediators causes a self-perpetuating vicious cycle of tissue destruction and repair. A matrix-based therapy using a heparan sulfate (HS) analogue called ReGeneraTing Agent (RGTA) replaces destroyed HS by binding to available heparin-binding sites of structural molecules, leading to restoration of tissue homeostasis in several inflammatory tissue injuries, including a hamster periodontitis model.

Methods: The ability of RGTA to restore the periodontium was tested in a model of -infected Balb/cByJ mice.

NAMPT expression in osteoblasts controls osteoclast recruitment in alveolar bone remodeling.

In bone remodeling, osteoclasts are recruited via increased production of RANKL (receptor activator of nuclear factor-κB ligand) and migrate to the bone surface, aided by matrix metalloproteinases (MMPs). NAMPT (nicotinamide phosphoribosyl transferase), which catalyzes the rate-limiting step in the NAD salvage pathway, increases during in vitro osteogenic differentiation and inhibits RANKL-induced osteoclast differentiation. Alveolar bone loss, due to disturbance of the remodeling process, is a major feature of periodontitis.

Coordination of early cellular reactions during activation of bone resorption in the rat mandible periosteum: An immunohistochemical study.

The activation step of bone remodeling remains poorly characterized. Activation comprises determination of the site to be remodeled, osteoclast precursor recruitment, their migration to the site of remodeling, and differentiation. These actions involve different compartments and cell types.

RGTA or ReGeneraTing Agents mimic heparan sulfate in regenerative medicine: from concept to curing patients.

The importance of extracellular matrix (ECM) integrity in maintaining normal tissue function is highlighted by numerous pathologies and situations of acute and chronic injury associated with dysregulation or destruction of ECM components. Heparan sulfate (HS) is a key component of the ECM, where it fulfils important functions associated with tissue homeostasis. Its degradation following tissue injury disrupts this delicate equilibrium and may impair the wound healing process.

RGTA-based matrix therapy - A new branch of regenerative medicine in locomotion.

Matrix therapy is an innovative, minimally invasive approach in the field of regenerative medicine, that aims to promote tissue regeneration by reconstructing the cellular microenvironment following tissue injury. This approach has significant therapeutic potential in the treatment of pathologies characterized by tissue inflammation and damage, or following injury, conditions which can be incapacitating and cost-consuming. Heparan sulfate mimics, termed ReGeneraTing Agents (RGTAs) have emerged as a unifying approach to treat these diverse pathologies.

'Pre-prosthetic use of poly(lactic-co-glycolic acid) membranes treated with oxygen plasma and TiO2 nanocomposite particles for guided bone regeneration processes'.

Objectives: Guided bone regeneration (GBR) processes are frequently necessary to achieve appropriate substrates before the restoration of edentulous areas. This study aimed to evaluate the bone regeneration reliability of a new poly-lactic-co-glycolic acid (PLGA) membrane after treatment with oxygen plasma (PO2) and titanium dioxide (TiO2) composite nanoparticles.

Methods: Circumferential bone defects (diameter: 10mm; depth: 3mm) were created on the parietal bones of eight experimentation rabbits and were randomly covered with control membranes (Group 1: PLGA) or experimental membranes (Group 2: PLGA/PO2/TiO2).

Periosteum Metabolism and Nerve Fiber Positioning Depend on Interactions between Osteoblasts and Peripheral Innervation in Rat Mandible.

The sympathetic nervous system controls bone remodeling by regulating bone formation and resorption. How nerves and bone cells influence each other remains elusive. Here we modulated the content or activity of the neuropeptide Vasoactive Intestinal Peptide to investigate nerve-bone cell interplays in the mandible periosteum by assessing factors involved in nerve and bone behaviors.

Relevance of surgical management of patients affected by bisphosphonate-associated osteonecrosis of the jaws. A prospective clinical and radiological study.

Objectives: Actually, consensus management of osteonecrosis of the jaws (ONJ) related to nitrogen-containing bisphosphonates (NBPs) is mostly a conservative approach. It does not always control the symptoms and the progression of the disease. The aim of this study was to evaluate the clinical and radiological outcomes of three therapeutic management strategies of established ONJ.

Glycosaminoglycan mimetic associated to human mesenchymal stem cell-based scaffolds inhibit ectopic bone formation, but induce angiogenesis in vivo.

Tissue engineering approaches to stimulate bone formation currently combine bioactive scaffolds with osteocompetent human mesenchymal stem cells (hMSC). Moreover, osteogenic and angiogenic factors are required to promote differentiation and survival of hMSC through improved vascularization through the damaged extracellular matrix (ECM). Glycosaminoglycans (GAGs) are ECM compounds acting as modulators of heparin-binding protein activities during bone development and regenerative processes.

Zoledronate effects on systemic and jaw osteopenias in ovariectomized periostin-deficient mice.

Osteoporosis and periodontal disease (PD) are frequently associated in the elderly, both concurring to the loss of jaw alveolar bone and finally of teeth. Bisphosphonates improve alveolar bone loss but have also been associated with osteonecrosis of the jaw (ONJ), particularly using oncological doses of zoledronate. The effects and therapeutic margin of zoledronate on jaw bone therefore remain uncertain.

Different sympathetic pathways control the metabolism of distinct bone envelopes.

Bone remodeling, the mechanism that modulates bone mass adaptation, is controlled by the sympathetic nervous system through the catecholaminergic pathway. However, resorption in the mandible periosteum envelope is associated with cholinergic Vasoactive Intestinal Peptide (VIP)-positive nerve fibers sensitive to sympathetic neurotoxics, suggesting that different sympathetic pathways may control distinct bone envelopes. In this study, we assessed the role of distinct sympathetic pathways on rat femur and mandible envelopes.

ReGeneraTing agents matrix therapy regenerates a functional root attachment in hamsters with periodontitis.

Matrix-based therapy restoring the cell microenvironment is a new approach in regenerative medicine successfully treating human chronic pathologies by using a heparan sulfate mimetic (ReGeneraTing agents [RGTA]). Periodontitis are inflammatory diseases destroying the tooth-supporting tissues with no satisfactory therapy. We studied in vivo RGTA ability to fully restore the tooth-supporting tissues.

Dense fibrillar collagen matrices sustain osteoblast phenotype in vitro and promote bone formation in rat calvaria defect.

Two pure collagen materials were prepared from acidic collagen solutions at 5 and 40 mg/mL. Benefits of collagen concentration on bone repair were evaluated in vitro with human calvaria cells and in vivo in a rat cranial defect. Both materials exhibited specific structures, 5 mg/mL was soft with an open porous network of fibrils; 40 mg/mL was stiffer with a plugged surface and bundles of collagen fibrils.

Structure and remodelling of the human parietal bone: an age and gender histomorphometric study.

Objective: Despite its clinical usefulness, the internal structure and remodelling of parietal bone remained poorly documented. The aim of this study was to gain reliable information on parietal bone remodelling in living humans.

Materials And Methods: This study provided a site-specific analysis of static indices of turnover in relation to gender and age by using leftovers of parietal bone sampled in 100 patients (78 females; 22 males, aged 16-79 years).

Bisphosphonate-associated osteonecrosis of the jaw: a key role of inflammation?

Osteonecrosis of the jaw (ONJ) can be associated with nitrogen-containing bisphosphonates (NBPs) therapy. Various mechanisms of NBP-associated ONJ have been proposed and there is currently no consensus of the underlying pathogenesis. The detailed medical and dental histories of 30 ONJ patients treated with NBPs for malignant diseases (24) or osteoporosis (6) were analyzed.

Histamine promotes osteoclastogenesis through the differential expression of histamine receptors on osteoclasts and osteoblasts.

In addition to the numerous roles of histamine in both the immune and nervous systems, previous studies have suggested that this bioamine might also be involved in bone metabolism. Following our observations of impaired bone resorption in ovariectomized rats after histamine receptor antagonist treatment, we focused in this study on osteoclasts and osteoclast precursors. We looked for a direct action of histamine on these cells using both in vivo and in vitro approaches.

Prostaglandin E2 synthesis in cartilage explants under compression: mPGES-1 is a mechanosensitive gene.

Knee osteoarthritis (OA) results, at least in part, from overloading and inflammation leading to cartilage degradation. Prostaglandin E2 (PGE2) is one of the main catabolic factors involved in OA. Its synthesis is the result of cyclooxygenase (COX) and prostaglandin E synthase (PGES) activities whereas NAD+-dependent 15 hydroxy prostaglandin dehydrogenase (15-PGDH) is the key enzyme implicated in the catabolism of PGE2.

An engineered biopolymer prevents mucositis induced by 5-fluorouracil in hamsters.

Oral mucositis is a common, treatment-limiting, and costly side effect of cancer treatments whose biological underpinnings remain poorly understood. In this study, mucositis induced in hamsters by 5-fluorouracil (5-FU) was observed after cheek-pouch scarifications, with and without administration of RGTA (RG1503), a polymer engineered to mimic the protective effects of heparan sulfate. RG1503 had no effects on 5-FU-induced decreases in body weight, blood cell counts, or cheek-pouch and jejunum epithelium proliferation rates, suggesting absence of interference with the cytotoxic effects of 5-FU.