Joachim Windolf

Depletion of neutrophil extracellular traps in vivo results in hypersusceptibility to polymicrobial sepsis in mice

IntroductionAlthough the formation of neutrophil (PMN) extracellular traps (NETs) has been detected during infection and sepsis, their role in vivo is still unclear. This study was performed in order to evaluate the influence of NETs depletion by administration of recombinant human (rh)DNase on bacterial spreading, PMN tissue infiltration and inflammatory response in a mouse model of polymicrobial sepsis.MethodsIn a prospective controlled double-armed animal trial, polymicrobial sepsis was induced by cecal ligation and puncture (CLP). After CLP, mice were treated with rhDNase or phosphate buffered saline, respectively. Survival, colony forming unit (CFU) counts in the peritoneal cavity, lung, liver and blood were determined. PMN and platelet counts, IL-6 and circulating free (cf)-DNA/NETs levels were monitored. PMN infiltration, as well as organ damage, was analyzed histologically in the lungs and liver. Capability and capacity of PMN to form NETs were determined over time.Resultscf-DNA/NETs were found to be significantly increased 6, 24, and 48 hours after CLP when compared to the levels determined in sham and naïve mice. Peak levels after 24 hours were correlated to enhanced capacity of bone marrow-derived PMN to form NETs after ex vivo stimulation with phorbol-12-myristate-13-acetate at the same time. rhDNase treatment of mice resulted in a significant reduction of cf-DNA/NETs levels 24 hours after CLP (P < 0.001). Although overall survival was not affected by rhDNase treatment, median survival after 24 hours was significantly lower when compared with the CLP group (P < 0.01). In mice receiving rhDNase treatment, CFU counts in the lung (P < 0.001) and peritoneal cavity (P < 0.05), as well as serum IL-6 levels (P < 0.001), were found to be already increased six hours after CLP. Additionally, enhanced PMN infiltration and tissue damage in the lungs and liver were found after 24 hours. In contrast, CFU counts in mice without rhDNase treatment increased later but more strongly 24 hours after CLP (P < 0.001). Similarly, serum IL-6 levels peaked after 24 hours (P < 0.01).ConclusionsThis study shows, for the first time, that depletion of NETs by rhDNase administration impedes the early immune response and aggravates the pathology that follows polymicrobial sepsis in vivo.

Distal radius fracture management in elderly patients: a literature review.

Distal radius fracture management in elderly patients remains without consensus regarding the appropriate treatment or anticipated outcome. Forty-one studies that included at least 10 patients with a minimum mean age of 65 years and that were indexed in Medline or Embase were reviewed. Treatment methods included pins and plaster, external fixation, K-wires, bone cement, and open reduction and internal fixation with plates. The methodological quality of each study was evaluated through use of a grading scale. Despite study heterogeneity, higher rates of infection were noted with external fixation and K-wire stabilization. Stratifying patients into low-demand and high-demand groups may improve the management of distal radius fractures in elderly patients. In sedentary patients with low demands, functional outcomes are good despite the presence of deformity. Patients with higher demands may benefit from fracture stabilization with locking volar plates. Volar plating with fixed-angle screws may be particularly suitable for elderly patients who may take longer to heal a fracture, be more susceptible to pin-track infection, and demonstrate earlier tendon irritation leading to rupture.

The clinical value of neutrophil extracellular traps

Neutrophil extracellular traps (NETs) have recently been discovered as a central part of antimicrobial innate immunity. In the meanwhile, evidence accumulated that NETs are also generated upon non-infectious stimuli in various clinical settings. In acute or chronic inflammatory disorders aberrantly enhanced NET formation and/or decreased NET degradation seems to correlate with disease outcome. This review summarizes current knowledge about the relation of NETs in a broad spectrum of clinical settings. Specifically, we focus on the importance of NETs as a predictive marker in severely ill patients and further, we speculate about the potential pathophysiology of NETs.

Combined use of platelet-rich plasma and autologous bone grafts in the treatment of long bone defects in mini-pigs

The use of platelet-rich plasma (PRP) for improving of bone defect healing is discussed controversially. The aim of this study was to assess the effect of PRP in combination with autologous cancellous graft on bone defect healing in a critical metaphyseal long bone defect. A critical size defect in the tibial metaphysis of 16 mini-pigs was filled either with autologous cancellous graft as control group or with autologous cancellous graft combined with autologous PRP. Compared to native blood platelets were enriched about 4.9-fold in the PRP. After 6 weeks, the specimens were assessed by X-ray and histological evaluation. Histomorphometrical analysis revealed that the area of new bone was significantly higher in the PRP group concerning the central area of the defect zone (p<0.02) as well as the cortical defect zone (p<0.01). All defects showed substantial new bone formation, but only defects of the PRP group regenerated entirely. The PRP group was superior to the control group even in the semi-quantitative assessment of the osseous bridging in both observed areas of the defect. Within the limits of the present study it could be demonstrated that PRP combined with autologous cancellous graft leads to a significantly better bone regeneration compared to isolated application of autologous cancellous graft in an in vivo critical size defect on load-bearing long bones of mini-pigs.

Distal radius fractures: current concepts.

Despite the frequency of distal radius fractures, the optimal treatment remains without consensus opinion. A trend toward increased distal radius fracture open reduction and internal fixation has been identified, with biomechanical and clinical studies suggesting treatment advantages of certain fixation methods over others. Well-controlled patient trials are still missing to lend objective findings to management algorithms. This article reviews the literature over the past 5 years to guide our management regarding this common upper-extremity injury.

Platelet-Rich Plasma on Calcium Phosphate Granules Promotes Metaphyseal Bone Healing in Mini-Pigs

The role of platelet‐rich plasma (PRP) as a promoter of bone healing remains controversial. The aim of this study was to investigate the effect of PRP in combination with calcium phosphate granules (CPG) on bone defect healing in a metaphyseal long bone defect. A metaphyseal bone defect at the proximal tibia of 16 mini‐pigs was filled with CPG combined with autologous PRP or CPG solely (control group). The PRP showed 4.4‐fold more platelets compared to peripheral blood. Six weeks after surgery the radiological and histomorphometrical evaluations showed significantly more bone formation in the PRP group in the central area of the defect zone (p < 0.01) as well as the cortical defect zone (p < 0.04). Furthermore, the resorption rate of CPG was increased in animals who received PRP. Nevertheless there were only isolated instances of complete osseous bridging of the bone defects even in the PRP group. This study demonstrates that a PRP‐CPG composit promotes bone regeneration but does not lead to a solid fusion of a tibial defect in mini‐pigs.

Diagnostic accuracy of neutrophil‐derived circulating free DNA (cf‐DNA/NETs) for septic arthritis

The release of “neutrophil extracellular traps” (NETs) has been identified as a novel immune response in innate immunity. NETs are composed of neutrophil‐derived circulating free DNA (cf‐DNA) and neutrophil cytoplasm‐derived proteins such as proteases. In this study, we analyzed the putative diagnostic value of synovial cf‐DNA/NETs for identification of septic arthritis. Forty‐two patients with a joint effusion who had undergone arthrocentesis were included. From synovial fluid, cf‐DNA/NETs (j‐cf‐DNA) levels were directly quantified. Diagnostic value of j‐cf‐DNA was compared with white blood cells (WBC), synovial white blood cells (j‐WBC), C‐reactive protein (CRP), j‐IL‐6, j‐TNF alpha, j‐IL‐1 beta, and myeloperoxidase (j‐MPO). Sensitivity, specificity, positive and negative predictive value, as well as ROC‐curves for each parameter were calculated. Synovial fluid cf‐DNA/NETs values from patients with septic arthritis (3,286 ± 386 ng/ml, n = 9) were significantly increased compared to patients with noninfectious joint inflammation (1,040 ± 208 ng/ml, n = 17) or osteoarthritis (278 ± 34 ng/ml, n = 16, p < 0.01). In conjunction with j‐cf‐DNA, j‐IL‐6 and j‐IL‐1 beta were significantly elevated (p < 0.01), but WBC, CRP, and j‐WBC were not. At a cut‐off of 300 ng/ml, j‐cf‐DNA had a sensitivity of 0.89, a specificity of 1.0, a positive predictive value of 1.0, and a negative predictive value of 0.97. Receiver operation curves revealed largest areas under the curve for cf‐DNA/NETs (0.933) and j‐IL‐6 (0.951). cf‐DNA/NETs seem to be a valuable additional marker for the diagnosis of septic arthritis or periprosthetic infections. However, this result should be confirmed in a large clinical trial.

Computerassistierte Verschraubung des hinteren Beckenrings

ZusammenfassungFragestellungComputerassistierte Verfahren sind in der Traumatologie von zunehmender Bedeutung. Als eine sinnvolle Indikation hat sich die iliosakrale Schraubeninsertion erwiesen, wobei bislang keine systematischen Untersuchungen dazu vorliegen, mit welchem Navigationsverfahren die besten Ergebnisse erzielt werden können. In einer experimentellen Untersuchung sollte die Praktikabilität eines für die Beckenchirurgie zugelassenen 3D-Bildwandlers für diese Indikation geprüft und mit bereits etablierten Navigationsverfahren verglichen werden.Material und MethodenDie Versuche wurden an 20 fixierten Humankadavern vorgenommen. Zur Durchführung der navigierten Prozedur wurde ein aktives optoelektronisches System verwendet. Die Verschraubung erfolgte perkutan in Rückenlage mit durchbohrten Spongiosaschrauben, wobei 4 Behandlungsgruppen gebildet wurden. Die postoperative Schnittbildgebung erfolgte mittels fluoroskopischem 3D-Scan und MSCT. Zielparameter der Untersuchung waren neben der Praktikabilität und Präzision der Verfahren die durchschnittliche Operations- und Durchleuchtungszeit pro instrumentierter Schraube.ErgebnisseAlle navigierten Verfahren führten im Vergleich zur konventionellen Technik zu einer Verlängerung der Operationszeit (2D: p<0,001, 3D: p>0,05, CT: p<0,001). Gleichzeitig wurde die intraoperative Durchleuchtungszeit bei Anwendung aller navigierten Verfahren signifikant gesenkt (p<0,001). Die Fehlplatzierungsrate betrug bei der konventionellen und der 2D-fluoroskopisch navigierten Verschraubung jeweils 20%, die Verfahren mit dreidimensionaler (3D-)Bilddarstellung blieben jeweils ohne Implantatfehllagen (p>0,05). Die CT-Navigation erwies sich für die untersuchte Indikation aufgrund des störanfälligen Registrierungsvorgangs und der häufig unzureichenden Matchingpräzision allerdings nur als bedingt geeignet.SchlussfolgerungenUnsere Daten zeigen, dass die fluoroskopisch navigierte Verschraubung des hinteren Beckenrings gegenüber der CT-Navigation hinsichtlich Praktikabilität und logistischem Aufwand eindeutige Vorteile aufweist. Beide bildwandlergestützten Navigationsverfahren senken darüber hinaus die intraoperative Strahlenbelastung im Vergleich zur konventionellen Technik. Eine verbesserte Präzision der Schraubenplatzierung kann eher durch Verwendung eines 3D-Bildwandlers erreicht werden, mit dem darüber hinaus die Schraubenplatzierung noch intraoperativ zuverlässig beurteilt werden kann.AbstractObjectiveComputer-assisted procedures have recently been introduced for navigated iliosacral screw placement. Currently there are only few data available reflecting results and outcome of the different navigated procedures which may be used for this indication. We therefore evaluated the features of a new 3D image intensifier used for navigated iliosacral screw placement compared to 2D fluoroscopic and CT navigation.Materials and methodsTwenty fixed human cadavers were used in this trial. Cannulated cancellous screws were percutaneously implanted in the supine position in four treatment groups. An optoelectronic system was used for the navigated procedures. Screw placement was postoperatively assessed by fluoroscopic 3D scan and CT. The target parameters of this investigation were practicability, precision as well as procedure and fluoroscopic time per screw.ResultsAll navigated procedures revealed a significant loss of time compared to non-navigated screw placement (2D: p<0.001, 3D: p>0.05, CT: p<0.001). Simultaneously a significant decrease of radiation exposure time was observed in the navigated groups (p<0.001 each). The misplacement rate was 20% in the non-navigated and the 2D fluoroscopic navigated group each. Procedures providing 3D imaging of the posterior pelvis did not produce any screw misplacement (p>0.05). However, the CT procedure was associated with time-consuming registration and high rates of failed matching procedures.ConclusionOur data show a clear benefit of using C-arm navigation for iliosacral screw placement compared with the CT-based procedure. While both fluoroscopy-based navigation procedures decrease intraoperative radiation exposure times, only 3D fluoroscopic navigation seems to improve the precision compared to non-navigated screw placement.

Functional results and complications following locking palmar plating on the distal radius: a retrospective study

This retrospective study investigates the radiological and the functional results as well as complications following locking palmar plating on the distal radius. Eighty-nine adult patients with a dorsally displaced distal radius fracture were treated using a locking palmar plate at our clinic over a period of 25 months. The radiological and functional results as well as the DASH score were recorded for 77 out of 89 patients in the routine final examinations conducted on average 12 months later. The radiological examinations showed a relevant shortening of the radius among five patients. A dorsal angulation of more than 20° as well as a radial inclination of less than 10° was observed in 11 patients. Most of the patients showed good to excellent functional and radiological results as well as good results on the DASH score. A3 fractures in elderly patients and the majority of C1 and C2 fractures can be safely treated with locking palmar plating.

Increased plasma kynurenine values and kynurenine-tryptophan ratios after major trauma are early indicators for the development of sepsis.

Kynurenine, the major degradation product of tryptophan has been shown to directly damage tissues, but its possible contribution to posttraumatic morbidity is unknown. Here, we studied the kinetics of kynurenine in patients after major trauma and whether this correlates with the development of posttraumatic sepsis. Kynurenine and tryptophan levels of 60 multiple-injured patients with Injury Severity Score of more than 16 were quantified prospectively by high-performance liquid chromatography. Blood samples were obtained daily from admission until day 10 after admission. Significantly increased kynurenine values were detectable already at day 1 after admission in blood from patients who later developed sepsis, regardless of injury pattern (P < 0.01). In contrast, kynurenine values of nonsepsis patients remained low throughout the observation period. However, all patients exhibited significantly decreased tryptophan values versus healthy controls (P < 0.01). Moreover, significantly increased kynurenine-tryptophan ratios rapidly predicted subsequent sepsis, multiple organ failure, and death (P < 0.01). Both increased kynurenine values and kynurenine-tryptophan ratios predicted posttraumatic development of sepsis and organ failure. This ought to be validated in subsequent studies.