Cytokine Expression in Human Osteoblasts After Antiseptic Treatment: A Comparative Study Between Polyhexanide and Chlorhexidine

Purpose/Aim of the study: Chlorhexidine and polyhexanide are frequently used antiseptics in clinical practice and have a broad antimicrobial range. Both antiseptics are helpful medical agents for septic wound treatment with a high potential for defeating joint infections. Their effect on human osteoblasts has, so far, not been sufficiently evaluated. The aim of this study was to investigate the activating potential of polyhexanide and chlorhexidine on inflammatory cytokines/chemokines in human osteoblasts in vitro. Materials and Methods: Human osteoblasts were isolated and cultivated in vitro and then treated separately with 0.1% and 2% chlorhexidine and 0.04% polyhexanide as commonly applied concentrations in clinical practice. Detection of cell structure and cell morphology was performed by light microscopic inspection. Cytokine and chemokine secretion was determined by using a multiplex suspension array. Results: Cell shrinking, defective cell membrane, and the loss of cell adhesion indicated cell damage of human osteoblasts after treatment with both antiseptics was evaluated by using light microscopy. Polyhexanide, but not chlorhexidine, caused human osteoblasts to secrete various interleukins (1β, 6, and 7), interferon γ, tumor necrosis factor α, vascular endothelial growth factor, eotaxin, fibroblast growth factor basic, and granulocyte macrophage colony-stimulating factor as quantified by multiplex suspension array. Conclusions: Both antiseptics induced morphological cell damage at an optimum exposure between 1 and 10 min. But only polyhexanide mediated a pronounced secretion of inflammatory cytokines and chemokines in human osteoblasts. Therefore, we recommend a preferred usage of chlorhexidine in septic surgery to avoid the induction of an inflammatory reaction.     

Fibrosis impairs the formation of new myofibers in the soft palate after injury

Muscle repair is a crucial component of palatoplasty but little is known about muscle regeneration after cleft palate repair. We hypothesized that the formation of new myofibers is hampered by collagen accumulation after experimental injury of the soft palate of rats. One‐millimeter excisional defects were made in the soft palates of 32 rats. The wound area was evaluated after 3, 7, 28, and 56 days using azocarmine G and aniline blue to stain for collagen and immunohistochemistry to identify myofibroblasts and to monitor skeletal muscle differentiation. To evaluate age effects, 16 unwounded animals were evaluated at 3 and 56 days. Staining was quantified by image analysis, and one‐way ANOVA was used for the statistical analysis. At day 56, the area percentage of collagen‐rich tissue was higher in the injured palatal muscles (46.7 ± 6.9%) than in nonwounded controls (15.9 ± 1.0%, p < 0.05). Myofibroblasts were present in the injured muscles at days 3 and 7 only. The numbers of proliferating and differentiating myoblasts within the wound area were greater at day 7 (p < 0.05), but only a few new myofibers had formed by 56 days. No age effects were found. The results indicate that surgical wounding of the soft palate results in muscle fibrosis. Although activated satellite cells migrated into the wound area, no new myofibers formed. Thus, regeneration and function of the soft palate muscles after injury may be improved by regenerative medicine approaches.     

Activated protein C resistance: molecular mechanisms based on studies using purified Gln506-factor V

Gln506-factor V (FV) was purified from plasma of an individual homozygous for an Arg506Gln mutation in FV that is associated with activated protein C (APC) resistance. Purified Gln506-FV, as well as Gln506-FVa generated by either thrombin or FXa, conveyed APC resistance to FV-deficient plasma in coagulation assays. Clotting assay studies also suggested that APC resistance does not involve any abnormality in FV-APC-cofactor activity. In purified reaction mixtures, Gln506-FVa in comparison to normal FVa showed reduced susceptibility to APC, because it was inactivated approximately 10-fold slower than normal Arg506-FVa. It was previously reported that inactivation of normal FVa by APC involves an initial cleavage at Arg506 followed by phospholipid- dependent cleavage at Arg306. Immunoblot and amino acid sequence analyses showed that the 102-kD heavy chain of Gln506-FVa was cleaved at Arg306 during inactivation by APC in a phospholipid-dependent reaction. This reduced but measurable susceptibility of Gln506-FVa to APC inactivation may help explain why APC resistance is a mild risk factor for thrombosis because APC can inactivate both normal FVa and variant Gln506-FVa. In summary, this study shows that purified Gln506- FV can account for APC resistance of plasma because Gln506-FVa, whether generated by thrombin or FXa, is relatively resistant to APC.