Polymorphonuclear leucocyte migration response in uneventful wound healing following trauma surgery. A contribution to the search for objectifiable criteria in wound healing monitoring

Nanotopography-based strategy for the precise manipulation of osteoimmunomodulation in bone regeneration

Immune cells play vital roles in regulating bone dynamics. Successful bone regeneration requires a favourable osteo-immune environment. The high plasticity and diversity of immune cells make it possible to manipulate the osteo-immune response of immune cells, thus modulating the osteoimmune environment and regulating bone regeneration. With the advancement in nanotechnology, nanotopographies with different controlled surface properties can be fabricated. On tuning the surface properties, the osteo-immune response can be precisely modulated. This highly tunable characteristic and immunomodulatory effects make nanotopography a promising strategy to precisely manipulate osteoimmunomdulation for bone tissue engineering applications. This review first summarises the effects of the immune response during bone healing to show the importance of regulating the immune response for the bone response. The plasticity of immune cells is then reviewed to provide rationales for manipulation of the osteoimmune response. Subsequently, we highlight the current types of nanotopographies applied in bone biomaterials and their fabrication techniques, and explain how these nanotopographies modulate the immune response and the possible underlying mechanisms. The effects of immune cells on nanotopography-mediated osteogenesis are emphasized, and we propose the concept of "nano-osteoimmunomodulation" to provide a valuable strategy for the development of nanotopographies with osteoimmunomodulatory properties that can precisely regulate bone dynamics.

Priming effects of lipopolysaccharide and inflammatory cytokines on canine granulocytes

Granulocytes play a pivotal role in natural immunity. Under inflammatory conditions, granulocytes are universally primed by several agents, such as endotoxins and inflammatory cytokines. Primed granulocytes exert potent adhesiveness, chemotaxis, phagocytosis and reactive oxygen species (ROS) production, effectively eliminating invading agents. Reactivity against priming agents is known to vary with species; however, there have been few reports on the effects of priming agents on canine granulocytes. In the present study, we assayed the priming effects of lipopolysaccharide (LPS), recombinant canine tumor necrosis factor-alpha (rcTNF-alpha) and recombinant canine granulocyte macrophage colony-stimulating factor (rcGM-CSF) on canine granulocyte function in vitro. Isolated recombinant canine were primed with various concentrations of LPS, rcTNF-alpha and rcGM-CSF, and CD11b expression was assayed. Furthermore, actin polymerization, phagocytosis and ROS production were then assayed at primer concentrations where enhancement of CD11b expression was observed. LPS did not enhance canine granulocyte function. Phagocytosis and actin polymerization were not enhanced by priming agents; however, rcTNF-alpha and rcGM-CSF enhanced CD11b expression and ROS production in canine granulocytes. These results suggest that priming effects are mainly reflected in CD11b expression and ROS production, with rcGM-CSF and rcTNF-alpha having a priming effect similar to that observed in humans.

Local expression of tumor necrosis factor-alpha and interleukin-10 on wound healing of intestinal anastomosis during endotoxemia in mice

BACKGROUND

This study aimed to evaluate the integrity of anastomotic wound healing after digestive surgery under septic conditions and define the participation of local expression of tumor necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10) around the anastomotic segment.

MATERIALS AND METHODS

Experimental animals were divided into lipopolysaccharide (LPS) and control groups, which had either LPS or normal saline solution injected into the peritoneal cavity 24 h before transection and anastomosis of the colon. Anastomotic bursting pressure (ABP) and tissue hydroxyproline concentration (HP) were measured as indicators of wound healing. Immunohistochemical staining for TNF-alpha and IL-10 on tissue samples obtained from the anastomotic segment were examined 1, 6, and 24 h after the operation. The reactive cells were counted under light microscopy.

RESULTS

ABP and HP were significantly lower in the LPS group than in the control group 7 days after surgery. In the LPS group, TNF-alpha expression increased about threefold over that in the control group 1 h after the operation. TNF-alpha-reactive cells were observed until 24 h after the operation in the LPS group, but not in the control group. On the other hand, IL-10 was not expressed in the control group during the observed period, whereas IL-10 was observed 24 h after the operation in the LPS group.

CONCLUSIONS

It is suggested that anastomotic wound healing was impaired after the digestive surgery in animals treated with intraperitoneal LPS, and that local expression of TNF-alpha and IL-10 at the anastomotic site acts as an inhibitory factor in the wound healing process.

The influence of trauma on changes in neutrophil granulocyte function assessed by an analysis of granulocyte migration

We examined the effects of trauma on polymorphonuclear leucocyte (PMN) migratory parameters and PMN elastase release, with the aim of tracing an acute inflammatory reaction from its very beginning to the phase of recovery. Fifteen patients who underwent monotrauma surgery, followed by uneventful healing, served as inflammation model. PMN activation was studied by measuring their readiness to migrate (TMI) and their penetration potency (DC) in a whole blood membrane filter device, in which a chemoattractant depot (FMLP) was integrated. Control chambers lacking FMLP provided parameters of the spontaneous migration. In healthy controls (n = 64), the numbers of invading PMNs decreased continuously from the outermost layer towards the interior of the filter device. FMLP did not influence the mobilization rate of PMNs immigrant from the blood into the filter, but those cells that did migrate penetrated deeper (P < 0.05). After trauma, the spontaneous and FMLP-stimulated DC was increased (P < 0.05). Trauma also tended to inhibit PMN migratory activity episodically; depression of the unspecific immune function (low TMI values) was found on the 3rd (P < 0.0001) and 12th (P < 0.01) postsurgical days. There was no correlation between the migratory parameters and the inflammation parameter, PMN elastase release. Preliminary results indicate that analyses of PMN migratory parameters by a whole blood membrane filter assay could provide a valuable adjunct in monitoring trauma-associated immunologic changes.