Beta-defensin 14 (Rattus norvegicus)

To address periprosthetic joint infection (PJI), a formidable complication after joint arthroplasty, an implant with excellent osseointegration and effective antibacterial activity has being extensively pursued and developed. In this work, the mouse beta-defensin-14 (MBD-14) was immobilized on the polyetheretherketone (PEEK) surface with three-dimensional (3D) porous structure to improve its antibacterial activity and osseointegration. An in vitro antibacterial evaluation showed that the porous PEEK loaded with MBD-14 wages a durable and effective fight against both Staphylococcus aureus (gram-positive) and Pseudomonas aeruginosa (gram-negative). In addition to the superior antibacterial activity, we found that the enhanced proliferation and osteogenic differentiation of bone mesenchymal stem cells were verified through various in vitro analyses. To evaluate the in vivo bactericidal effect and osseointegration of the samples, the rat femoral models with infection and non-infection were established. The enhanced osseointegration of the MBD-14-loaded samples was found in both two in vivo models. And no bacteria survived on the surfaces of samples with a relatively high MBD-14 concentration. Above results indicate that the 3D porous PEEK coating loaded with MBD-14 simultaneously yields excellent osseointegration while exerting durable and broad-spectrum antibacterial activity. And it paves the way for PEEK to be applied clinically to address PJI. STATEMENT OF SIGNIFICANCE: (1). By using the physio-chemical technique including sulfonation and lyophilization etc., a three-dimensional porous network is developed on polyetheretherketone (PEEK) surface, in which mouse beta-defensin-14 (MBD-14, a broad-spectrum antimicrobial peptide) is then loaded. It endows PEEK with antibacterial activity and osseointegration. (2). Two in vivo animal models with infection and non-infection are used to prove the new bone formation around the samples. (3). Supplementary material also proves that MBD-14 promotes the osteogenic differentiation of BMSCs. However, its potential mechanism needs to be further studied in future. (4). The modified PEEK, including excellent osseointegration and a durable and broad-spectrum antibacterial activity, could be applied clinically to address PJI which is a hot potato for surgeons and patients undergoing total joint arthroplasty.

Aim: The aim of this study was to evaluate the effects of Bdellovibrio bacteriovorus HD100 on experimental periodontitis (EP) in rats. Methods: Thirty-two rats were divided into four groups: control, C-HD100 (B. bacteriovorus), EP, and EP-HD100. On day 0, EP was induced by the placement of cotton ligatures around the mandibular first molars (MFMs) in the EP and EP-HD100 groups. In the C-HD100 and EP-HD100 groups, suspensions containing 1 × 109 PUF/ml of B. bacteriovorus HD100 were topically administered to the subgingival region of MFMs on days 0, 3, and 7. Animals were euthanized on day 14. Morphometrics analyses were performed in hemimandibles. The levels of tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, IL-10, IL-1β, transforming growth factor beta (TGF-β), macrophage colony-stimulating factor (M-CSF) and regulated on activation and normal T cell expressed and secreted (RANTES) were determined by enzymatic immunoassays in gingival tissues. Beta defensin (BD)-1, BD-2, and BD-3, Toll-like receptors (TLR)-2 and TLR-4, and a cluster of differentiation (CD)-4, CD-8 and CD-57 were analyzed by immunohistochemistry in hemimandibles. Data were statistically analyzed. Results: The EP group showed greater alveolar bone loss than EP-HD100 (p < .05). The EP-HD100 group showed higher levels of MCP-1, RANTES, IL-10, and TGF-β, lower levels of TNF-α than the EP group (p < .05). No differences were observed in IL-1β, IL-6, and M-CSF levels between EP and EP-HD100 groups. The C-HD100 group had higher IL-6, TNF-α, RANTES, and MCP-1 levels than the control group (p < .05). Regarding BD, the EP-HD100 group showed a larger immunolabeling pattern for BD-1, BD-2, and BD-3 than the EP group (p < .05). No significant differences in the immunolabeling pattern were observed for TLR-2, TLR-4, CD-4, CD-8, and CD-57 between EP and EP-HD100 groups. Conclusion: The topical use of B. bacteriovorus HD100 reduces alveolar bone loss, increases expression of BD, and modulates the cytokines levels on periodontal tissues in rats with EP.

Approximately 40-50 β-defensins are predominantly expressed in the male reproductive system of mammals. This selective expression raises the question as to the roles of these molecules in innate immunity and fertility in the male reproductive tract. Rat β-defensin 22 is an epididymis-specific β-defensin expressed in segments 12-14 of the epididymis. This protein contains both β-defensin and lectin signature sequences, yet its antimicrobial activity and carbohydrate-binding ability have not been shown. We herein demonstrated the antimicrobial activity of recombinant rat β-defensin 22 against Escherichia coli and Candida albicans. Its lectin-like activity was also investigated by demonstrating its binding ability with heparin beads. This heparin-binding activity implies some potential roles for this defensin in determining the fertilisation capabilities of sperm.