Shift of Neutrophils From Blood to Bone Marrow Upon Extensive Experimental Trauma Surgery.

Introduction: Extensive trauma surgery evokes an immediate cellular immune response including altered circulatory neutrophil numbers. The concurrent bone marrow (BM) response however is currently unclear. We hypothesize that these BM changes include (1) a relative reduction of the bone marrow neutrophil fraction and (2) increasing heterogeneity of the bone marrow neutrophil pool due to (3) the appearance of aged/returning neutrophils from circulation into the BM-compartment.

Standardized porcine unilateral femoral nailing is associated with changes in PMN activation status, rather than aberrant systemic PMN prevalence.

Purpose: Intramedullary nailing (IMN) of fractures is associated with increased rates of inflammatory complications. The pathological mechanism underlying this phenomenon is unclear. However, polymorphonuclear granulocytes (PMNs) seem to play an important role.

Instant intra-operative neutropenia despite the emergence of banded (CD16/CD62L) neutrophils in peripheral blood - An observational study during extensive trauma-surgery in pigs.

Introduction: Deregulation of polymorphonuclear neutrophils (PMNs) is an essential step in the development of inflammatory complications upon trauma. Different neutrophil subtypes have been identified recently, however, the role of neutrophil subtypes in immunoregulation upon trauma is unclear. We hypothesize that extensive trauma surgery causes instant progressive heterogeneity of the blood neutrophil pool, and increased appearance of young (CD16/CD62L) neutrophils in peripheral blood.

An increase in myeloid cells after severe injury is associated with normal fracture healing: a retrospective study of 62 patients with a femoral fracture.

Background and purpose-Nonunion is common in femoral fractures. Previous studies suggested that the systemic immune response after trauma can interfere with fracture healing. Therefore, we investigated whether there is a relation between peripheral blood cell counts and healing of femur fractures.

Differential antibacterial control by neutrophil subsets.

Neutrophils comprise a heterogeneous population of cells essential for bacterial eradication, and defects in neutrophil function are associated with increased susceptibility to infection. In this study, neutrophils from healthy controls were shown to prevent bacterial proliferation for at least 48 hours when cocultured with methicillin-resistant (MRSA) in tissue-like scaffolds by establishing a bacteriostatic environment inside their phagolysosome. This intracellular bacterial containment is independent of reactive oxygen species because neutrophils that lack a functional nicotinamide adenine dinucleotide phosphate-oxidase complex displayed no defect in intracellular bacterial containment, whereas killing of the pathogen was impaired.

A Rise in Neutrophil Cell Size Precedes Organ Dysfunction After Trauma.

Introduction: Organ dysfunction remains a major cause of morbidity after trauma. The development of organ dysfunction is determined by the inflammatory response, in which neutrophils are important effector cells. A femoral fracture particularly predisposes for the development of organ dysfunction.

Human CD62L neutrophils identified as a separate subset by proteome profiling and in vivo pulse-chase labeling.

During acute inflammation, 3 neutrophil subsets are found in the blood: neutrophils with a conventional segmented nucleus, neutrophils with a banded nucleus, and T-cell-suppressing CD62L neutrophils with a high number of nuclear lobes. In this study, we compared the in vivo kinetics and proteomes of banded, mature, and hypersegmented neutrophils to determine whether these cell types represent truly different neutrophil subsets or reflect changes induced by lipopolysaccharide (LPS) activation. Using in vivo pulse-chase labeling of neutrophil DNA with 6,6-H-glucose, we found that H-labeled banded neutrophils appeared much earlier in blood than labeled CD62L and segmented neutrophils, which shared similar label kinetics.

Invasive surgery reduces infarct size and preserves cardiac function in a porcine model of myocardial infarction.

Reperfusion injury following myocardial infarction (MI) increases infarct size (IS) and deteriorates cardiac function. Cardioprotective strategies in large animal MI models often failed in clinical trials, suggesting translational failure. Experimentally, MI is induced artificially and the effect of the experimental procedures may influence outcome and thus clinical applicability.

Mechanical ventilation is the determining factor in inducing an inflammatory response in a hemorrhagic shock model.

Background: Hemorrhagic shock (HS) is known to induce an inflammatory response by activating the immune system. This response is mainly caused by primed polymorphonuclear granulocytes (PMNs). Trauma patients often require mechanical ventilation (MV), which can cause additional pulmonary and systemic inflammation.

Immunophenotyping of posttraumatic neutrophils on a routine haematology analyser.

Introduction: Flow cytometry markers have been proposed as useful predictors for the occurrence of posttraumatic inflammatory complications. However, currently the need for a dedicated laboratory and the labour-intensive analytical procedures make these markers less suitable for clinical practice. We tested an approach to overcome these limitations.

The effect of C1-esterase inhibitor on systemic inflammation in trauma patients with a femur fracture - The CAESAR study: study protocol for a randomized controlled trial.

Background: Systemic inflammation in response to a femur fracture and the additional fixation is associated with inflammatory complications, such as acute respiratory distress syndrome and multiple organ dysfunction syndrome. The injury itself, but also the additional procedure of femoral fixation induces a release of pro-inflammatory cytokines such as interleukin-6. This results in an aggravation of the initial systemic inflammatory response, and can cause an increased risk for the development of inflammatory complications.