Local application of ibandronate/gelatin sponge improves osteotomy healing in rabbits

Bisphosphonate-Functionalized Scaffolds for Enhanced Bone Regeneration

The local sustained release of bioactive substances are attracting increasing attention in bone tissue engineering, which is beneficial to bone tissue formation and helps to improve the bone ingrowth ability of a scaffold. Bisphosphonates (BPs), as a representative kind of osteoclast inhibitors, are proven to possess excellent osteogenic induction capability. Accordingly, various physical and chemical strategies are developed to functionalize bone tissue scaffolds with BPs to achieve controlled release profiles. Compared with traditional treatment modalities, local release of BPs from these composite scaffolds will contribute to continuous bone integration without the risk of many complications. This review explores the molecular mechanisms of BPs on bone metabolism and analyzes the appropriate concentrations of BPs that promote bone regeneration. The advanced BP loading strategies, implant modification technologies, and BP-loaded composite scaffolds based on different matrices are summarized. Finally, the latest advances and the future development of BP-modified scaffolds for enhanced bone regeneration are discussed. This article provides leading-edge design strategies of the BP-functionalized bone engineering scaffolds for improved bone repairability.

Protein S100-A7 Derived from Digested Dentin Is a Critical Molecule for Dentin Pulp Regeneration

Dentin consists of inorganic hard tissue and organic dentin matrix components (DMCs). Various kinds of bioactive molecules are included in DMCs and some of them can be released after digestion by endogenous matrix metalloproteinases (MMPs) in the caries region. Digested DMCs induced by MMP20 have been reported to promote pulpal wound healing processes, but the released critical molecules responsible for this phenomenon are unclear. Here, we identified protein S100-A7 as a critical molecule for pulpal healing in digested DMCs by comprehensive proteomic approaches and following pulp capping experiments in rat molars. In addition, immunohistochemical results indicated the specific distribution of S100-A7 and receptor for advanced glycation end-products (RAGE) as receptor for S100-A7 in the early stage of the pulpal healing process, and following accumulation of CD146-positive stem cells in wounded pulp. Our findings indicate that protein S100-A7 released from dentin by MMP20 might play a key role in dentin pulp regeneration.

Gelfoam Interposition Minimizes Risk of Fistula and Postoperative Bleeding in Modified-Furlow Palatoplasty

Failure to accomplish a tension-free, watertight closure predisposes the palatoplasty patient to fistula formation. Perioperative bleeding also places the patient at risk for adverse airway events (AAE). This study introduces the incorporation of a hemostatic gelatin sponge (Gelfoam) into layered palatoplasty to minimize adverse postoperative bleeding and fistula formation. A retrospective chart review was performed to identify subjects who underwent Furlow palatoplasty with insertion of Gelfoam from 2010 to 2015. Exclusion criteria include age >3 years, prior palate surgery, <30-day follow-up, immunosuppressive state, and diagnosis of Treacher-Collins or Apert Syndrome. Demographic data include age, sex, cleft laterality, prior surgeries, Veau classification, Pierre Robin status, and tracheostomy dependence. Primary outcome was fistula formation. Secondary outcomes included perioperative metrics and AAE.One hundred subjects met criteria, 45% female. Average age was 14.6 months. Subjects with syndromes comprised 28%, with 16% diagnosed with Pierre Robin. Two subjects were tracheostomy-dependent. Prior cleft and mandibular procedures were performed in 55%. Isolated palatal defects were seen in 46%, unilateral lip and palate in 41%, and bilateral lip and palate in 13%. The majority of defects were Veau II and III (35% and 34%, respectively). Adverse airway events occurred in 2%, one of which resulted in reintubation. One subject (1%) was found to have a postoperative fistula.The incorporation of Gelfoam in the modified-Furlow palatoplasty results in a low rate of oronasal fistula (1%) and low perioperative risk of AAE. Further prospective comparison of this method to others will be the focus of future work.

Paradoxical side effects of bisphosphonates on the skeleton: What do we know and what can we do?

Bisphosphonates are considered the most effective drugs for controlling adult and pediatric osteolytic diseases. Although they have been used successfully for many years, several side effects, such as osteonecrosis of the jaw, delayed dental eruption, atypical femoral fracture, and alterations to the bone growth system, have been described. After an overview of nitrogenous bisphosphonate, the purpose of this article is to describe their mechanisms of action and current applications, review the preclinical and clinical evidence of their side effects in the skeleton ("what we know"), and describe current recommendations for preventing and managing these effects ("what we can do"). Finally, promising future directions on how to limit the occurrence of these side effects will be presented.

Local application of an ibandronate/collagen sponge improves femoral fracture healing in ovariectomized rats

Non-union is a major clinical problem in the healing of fractures, especially in patients with osteoporosis. The systemic administration of drugs is time consuming and large doses are demanding and act slowly, whereas local release acts rapidly, increases the quality and quantity of the bone tissue. We hypothesize that local delivery demonstrates better therapeutic effects on an osteoporotic fracture. The aim of this paper is to investigate the effect of the local application of ibandronate loaded with a collagen sponge on regulating bone formation and remodeling in an osteoporotic rat model of fracture healing. We found that the local delivery of ibandronate exhibited excellent effects on improving the bone microarchitecture and suppressed effects on bone remodeling. At 4 weeks, more callus formation and improvement of mechanical character and microstructure were observed in a local delivery via μCT, mechanical test, histological research and serum analysis. The suppression of bone remodeling was compared with a systemic treatment at 12 weeks, and the structural mechanical properties and microarchitecture were also improved with local delivery. This research identifies an earlier, safer and integrated approach for local delivery of ibandronate with collagen and provides a better strategy for the treatment of osteoporotic fracture in rats.