Daniel Busch

Protective Role of Peroxisome Proliferator–activated Receptor-β/δ in Septic Shock

RATIONALE Peroxisome proliferator-activated receptor (PPAR)-β/δ is a transcription factor that belongs to the PPAR nuclear hormone receptor family, but the role of PPAR-β/δ in sepsis is unknown. OBJECTIVES We investigated the role of PPAR-β/δ in murine models of LPS-induced organ injury and dysfunction and cecal ligation and puncture (CLP)-induced polymicrobial sepsis. METHODS Wild-type (WT) and PPAR-β/δ knockout (KO) mice and C57BL/6 mice were subjected to LPS for 16 hours. C57BL/6 mice received the PPAR-β/δ agonist GW0742 (0.03 mg/kg intravenously, 1 h after LPS) or GW0742 plus the PPAR-β/δ antagonist GSK0660 (0.1 mg/kg intravenously, 30 min before LPS). CD-1 mice subjected to CLP received GW0742 or GW0742 plus GSK0660. MEASUREMENTS AND MAIN RESULTS In PPAR-β/δ KO mice, endotoxemia exacerbated organ injury and dysfunction (cardiac, renal, and hepatic) and inflammation (lung) compared with WT mice. In C57BL/6 mice subjected to endotoxemia, GW0742 significantly (1) attenuated organ (cardiac and renal) dysfunction and inflammation (lung); (2) increased the phosphorylation of Akt and glycogen synthase kinase (GSK)-3β; (3) attenuated the increase in extracellular signal-regulated kinase (ERK)1/2 and signal transducer and activator of transcription (STAT)-3 phosphorylation; and (4) attenuated the activation of nuclear factor (NF)-κB and the expression of inducible nitric oxide synthase (iNOS). In CD-1 mice subjected to CLP, GW0742 improved 10-day survival. All the observed beneficial effects of GW0742 were attenuated by the PPAR-β/δ antagonist GSK0660. CONCLUSIONS PPAR-β/δ protects against multiple organ injury and dysfunction, and inflammation caused by endotoxic shock and improves survival in polymicrobial sepsis by a mechanism that may involve activation of Akt and inhibition of GSK-3β and NF-κB.

Laparotomy closure using an elastic suture: A promising approach

BACKGROUND Midline laparotomy wound failure like burst abdomen remains one of the major complications after abdominal surgery. The use of sutures with a closer resemblance to abdominal wall physiology, like elastic threads, could decrease the risk of these complications occurring. Thus, we evaluated the possibility of using a new elastic thread composed of thermoplastic polyurethane (TPU) as a suture for the closure of midline laparotomies compared to conventionally used polypropylene (PP) in a rabbit model. METHODS The elastic TPU thread was processed and tensile tests were performed. Twenty female chinchilla rabbits underwent midline laparotomy. They were randomized to a TPU and a PP group depending on the suture used for fascia closure. After 7 or 21 days, the abdominal walls were assessed macroscopically for wound healing complications and were explanted for histopathological investigation. RESULTS Tensile tests showed a mean elastic elongation of 55.5% and a sufficient material strength of the TPU thread. In animal experiments, there was no difference between the groups at 7 days; however, the TPU suture showed significantly less CD68 positive cells (p < 0.001) and a higher collagen I/III ratio (p = 0.011) than PP did after 21 days. The amount of apoptotic cells was significantly elevated in the TPU group (p = 0.007) after 21 days. No differences were found concerning granuloma size and number of Ki67-positive cells. CONCLUSIONS The newly developed TPU thread shows promising tensile characteristics. Midline laparotomy closure is feasible and safe in a rabbit model. Immunohistochemistry indicates similar biocompatibility and wound healing after implantation compared to PP after 21 days. To confirm these findings and to proof long-term capability further studies need to be conducted.

First in vivo visualization of MRI-visible IPOM in a rabbit model

BACKGROUND Application of a mesh in presence of pneumoperitoneum may cause deformation or wave formation when gas is released. Moreover, mesh shrinkage during subsequent wound healing cannot be detected in vivo without invasive diagnostics. Using MRI-visible polyvinylidene fluoride (PVDF) mesh, the extend of mesh deformation and shrinkage could be objectified by MRI for the first time. MATERIALS AND METHODS Laparoscopic intraperitoneal onlay mesh (IPOM) implantation was performed in 10 female rabbits using ferro-oxide loaded PVDF meshes. MRI measurements were performed postoperatively at days 1 and 90. After three-dimensional reconstruction of all MRI images the total surface and the effective surface of the implanted mesh were explored and calculated computer-assisted. RESULTS In all cases, the mesh could be identified in MRI. The subsequent three-dimensional reconstruction always allowed a calculation of the mesh area. In relation to the original size of the used textile implant, we found neither a significant reduction of the effective mesh surface after release of the pneumoperitoneum at day 1 after laparoscopic surgery nor a significant change of the total surface of this large pore mesh by the end of the observation period. CONCLUSIONS In vivo investigation of mesh surface via MRI could exclude a significant initial reduction of the effective mesh surface after release of pneumoperitoneum, in this IPOM rabbit model. A further subsequent shrinkage of these large pore PVDF meshes could be excluded, as well. Imaging of MRI-visible IPOM mesh turned out to be a sufficient tool to objectify mesh configuration and position in vivo.

Utility of Magnetic Resonance Imaging to Monitor Surgical Meshes: Correlating Imaging and Clinical Outcome of Patients Undergoing Inguinal Hernia Repair.

ObjectivesFrom a surgeon’s point of view, meshes implanted for inguinal hernia repair should overlap the defect by 3 cm or more during implantation to avoid hernia recurrence secondary to mesh shrinkage. The use of magnetic resonance imaging (MRI)–visible meshes now offers the opportunity to noninvasively monitor whether a hernia is still covered sufficiently in the living patient. The purpose of this study was therefore to evaluate the efficacy of hernia repair after mesh implantation based on MRI findings (mesh coverage, visibility of hernia structures) and based on the patient’s postoperative symptoms. Materials and MethodsIn this prospective study approved by the ethics committee, 13 MRI-visible meshes were implanted in 10 patients (3 bilaterally) for inguinal hernia repair between March 2012 and January 2013. Senior visceral surgeons (>7 years of experience) implanted the meshes via laparoscopic transabdominal preperitoneal procedure. Magnetic resonance imaging was performed within 1 week and at 3 months after surgery at a 1.5-T system. Mesh position, deformation, and coverage of the hernia were visually assessed in consensus and rated on a 4-point semiquantitative scoring system. Distances of hernia center point to the mesh borders (overlap) were measured. Mesh position and hernia coverage postoperatively and at 3 months after implantation were correlated with the respective patients’ clinical symptoms. Statistical analysis was performed using the Wilcoxon signed rank test. ResultsTwo of the 13 meshes presented with an atypical mesh configuration along the course of psoas muscle with a short medial overlap of less than 2 cm. Eleven of the 13 meshes exhibited a typical mesh configuration with lateral folding and initial overlap of more than 2 cm. Between baseline and 3 months’ follow-up, average overlap decreased in the medial direction by −10% (3.75 cm vs 3.36 cm, P = 0.22), in the lateral direction by −20% (3.55 cm vs 2.82 cm, P = 0.01), in the superior direction by −2% (5.82 cm vs 5.72 cm, P = 0.55), and in the posterior direction by −19% (4.11 cm vs 3.34 cm, P = 0.01). Between baseline and 3 months’ follow-up, mesh folding increased mildly in the medial direction, whereas no change was found in the other directions. Individual folds of the mesh were flexible over time, whereas the gross visual configuration and location of meshes did not change. Four of the 13 former hernia sites were mildly painful at follow-up, whereas 9 of the 13 were completely asymptomatic. No correlation between clinical symptoms and mesh position or hernia coverage was found. ConclusionsOur results suggest that the actual postoperative mesh position after release of laparoscopic pneumoperitoneum may deviate from its position during surgery. Gross mesh position and configuration differed between patients but did not change within a given patient over the observation period of 3 months after surgery. We did not find a correlation between clinical symptoms and mesh configuration or position. Shrinkage of meshes does occur, yet not as concentric process, but regionally variable, leading to a reduced hernia coverage of up to −20% in the lateral and posterior directions.

Development of a standardized trauma-related lung injury model

BACKGROUND The pathophysiology of acute lung injury is multifactorial, and the mechanisms are difficult to prove. We have devised a study of two known and standardized animal models (hemorrhagic shock [HS] and oleic acid [OA]) to more closely reproduce the pathophysiology of posttraumatic acute lung injury. MATERIAL AND METHODS Pressure-controlled HS (group HS) was performed by withdrawing blood over 15-min until mean arterial pressure reached 35 mm Hg for 90 min. In an additional group, HS and standardized lung injury induced by OA were combined (group lung injury [HS + OA]). After the shock period, both groups were resuscitated over 15 min by transfusion of the removed blood and an equal volume of lactate Ringer solution. The end point was 6 h. Plasma interleukin (IL)-6, keratinocyte chemoattractant (KC), IL-10, monocyte chemoattractant protein-1 (MCP-1), and lung histology were carried out. RESULTS The posttraumatic lung injury group demonstrated significantly higher IL-6 levels when compared with HS group (744.8 ± 104 versus 297.7 ± 134 pg/mL; P = 0.004). Histologic analysis confirmed diffuse alveolar congestion and moderate-to-severe lung edema in animals with HS + OA. Lung injury was mild in mice with isolated HS or OA injection. CONCLUSIONS We established a posttraumatic lung injury model combining two different standardized protocols (HS and OA). This model leads to pronounced inflammation and lung injury. This model allows the analysis of the dynamics of sterile lung injury and associated organ dysfunction.

Influence of CD68+ macrophages and neutrophils on anastomotic healing following laparoscopic sigmoid resection due to diverticulitis

BackgroundThe aim of this prospective study was to evaluate the predictive value of a potential preexisting low-grade inflammation regarding the incidence of anastomotic leakage in elective laparoscopic sigmoid resection due to diverticulitis.MethodsPatients with either chronically recurrent diverticulitis or sigmoid stenosis caused by chronic diverticulitis were included in this study. All patients with acute local or systemic inflammation were excluded. Detailed patient information (e.g. American Society of Anesthesiologists (ASA) grade, comorbidities, duration of hospital stay, and anastomotic leakage) was prospectively recorded. CD68+ macrophages, neutrophils, CD3+ T-lymphocytes, CD11c+ dendritic cells, MHCII, TNFR1, and NF-κB were evaluated by immunohistochemistry within the acquired sample of colonic bowel wall tissue. Clinical and immunohistochemical data was compared between groups (leakage vs. no leakage). Additionally, a matched-pair analysis was performed due to the widely heterogeneous groups concerning the number of patients and to minimize the effect of extraneous variables.ResultsA total of 83 patients were included in the study, of which 7 patients suffered an anastomotic leakage. Neither the clinical nor the immunohistochemical parameters were significantly different between the groups. The matched-pair analysis revealed a nonsignificant increase in mean duration of hospital stay for the group with anastomotic leakage and a significantly higher percentage of CD68+ macrophages and neutrophils in the colonic wall obtained at the index operation in both the mucosal and submucosal layers for the leakage group.ConclusionsA preexisting low-grade inflammation represented by infiltrates of macrophages and neutrophils is a predictor for increased risk of developing colon anastomotic leakage.

Fulminant Epstein-Barr virus - infectious mononucleosis in an adult with liver failure, splenic rupture, and spontaneous esophageal bleeding with ensuing esophageal necrosis: a case report

IntroductionInfectious mononucleosis is a clinical syndrome most commonly associated with primary Epstein-Barr virus infection. The majority of patients with infectious mononucleosis recovers without apparent sequelae. However, infectious mononucleosis may be associated with several acute complications. In this report we present a rare case of esophageal rupture that has never been described in the literature before.Case presentationWe present the case of an 18-year-old Caucasian man affected by severe infectious mononucleosis complicated by fulminant hepatic failure, splenic rupture and esophageal necrosis.ConclusionsAlthough primary Epstein-Barr virus infection is rarely fatal, fulminant infection may occur - in this case leading to hepatic failure, splenic rupture and esophageal necrosis, subsequently making several surgical interventions necessary. We show here that infectious mononucleosis is not only a strictly medical condition, but can also lead to severe surgical complications.

Delayed activation of PPAR-β/δ improves long-term survival in mouse sepsis: effects on organ inflammation and coagulation:

Activation of peroxisome proliferator-activated receptor (PPAR)-β/δ reduces tissue injury in murine endotoxemia. We hypothesized that the PPAR-β/δ-agonist GW0742 improves long-term outcome after sepsis caused by cecal ligation and puncture (CLP). Fifty-one CD-1 female mice underwent CLP and received either vehicle (control), GW0742 (0.03 mg/kg/injection; five post-CLP i.v. injections), GSK0660 (PPAR-β/δ-antagonist) or both and were monitored for 28 d. Another 20 CLP mice treated with GW0742 and vehicle were sacrificed 24 h post-CLP to assess coagulopathy. Compared to vehicle, survival of CLP-mice treated with GW0742 was higher by 35% at d 7 and by 50% at d 28. CLP mice treated with GW0742 had 60% higher IFN-γ but circulating monocyte chemoattractant protein-1 and chemokine ligand were lower at 48 h post-CLP. Compared to vehicle, CLP mice treated with GW0742 exhibited a 50% reduction in the circulating plasminogen activator inhibitor-1 associated with an increase in platelet number at 24 h post-CLP (but no changes occurred in anti-thrombin-III, plasminogen, fibrinogen and clotting-times). CLP mice treated with GW0742 exhibited a similar increase in most of the biochemical markers of organ injury/dysfunction (lactate dehydrogenase, alanine aminotransferase, creatine kinase, creatinine, blood urea nitrogen, and triglycerides) measured. Treatment with GW0742 consistently improved long-term survival in septic CD-1 mice by partially modulating the post-CLP systemic cytokine response and coagulation systems.

Dose-dependent effects of peroxisome proliferator-activated receptors β/δ agonist on systemic inflammation after haemorrhagic shock

Introduction PPAR&bgr;/&dgr; agonists are known to modulate the systemic inflammatory response after sepsis. In this study, inflammation modulation effects of PPAR&bgr;/&dgr; are investigated using the selective PPAR&bgr;/&dgr; agonist (GW0742) in a model of haemorrhagic shock (HS)‐induced sterile systemic inflammation. Methods Blood pressure‐controlled (35 ± 5 mmHg) HS was performed in C57/BL6 mice for 90 min. Low‐dose GW0742 (0.03 mg/kg/BW) and high‐dose GW0742 (0.3 mg/kg/BW) were then administered at the beginning of resuscitation. Mice were sacrificed 6 h after induction of HS. Plasma levels of IL‐6, IL‐1&bgr;, IL‐10, TNF&agr;, KC, MCP‐1, and GM‐CSF were determined by ELISA. Myeloperoxidase (MPO) activity in pulmonary and liver tissues was analysed with standardised MPO kits. Results In mice treated with high‐dose GW0742, plasma levels of IL‐6, IL‐1&bgr;, and MCP‐1 were significantly increased compared to the control group mice. When compared to mice treated with low‐dose GW0742 plasma levels of IL‐6, IL‐1&bgr;, GM‐CSF, KC, and MCP‐1 were significantly elevated in high‐dose‐treated mice. Low‐dose GW0742 treatment was associated with a non‐significant downtrend of inflammatory factors in mice with HS. No significant changes of MPO activity in lung and liver were observed between the control group and the GW0742 treatment groups. Conclusion This study identified dose‐dependent effects of GW0742 on systemic inflammation after HS. While high‐dose GW0742 substantially enhanced the systemic inflammatory response, low‐dose GW0742 led to a downtrend of pro‐inflammation cytokine expression. The exact mechanisms are yet unknown and need to be assessed in further studies. HighlightsHigh dosage of GW0742 enhanced the plasma pro‐inflammatory cytokines levels.Low‐dose treatment of GW0742 induced a downtrend of inflammation cytokine levels.GW0742 treatment has no effect on the remote organ neutrophil infiltration.

Influence of gentamicin-coded PVDF suture material on the healing of intestinal anastomosis in a rat model

PurposeIntestinal anastomosis is a fundamental procedure in general surgery and required to restore intestinal continuity following resection. The aim of this study was to evaluate whether a gentamicin-coated polyvinylidene fluoride (PVDF) suture material has beneficial effect on anastomotic healing.MethodsNinety Sprague-Dawley rats were divided into three groups: a PVDF-suture group, a gentamicin-coated PVDF (GPVDF)-suture group and a control group using Maxon® (polyglycolid-co-trimethylene carbonate). For each animal, a colonic anastomosis was performed. Ten animals from each group were sacrificed on postoperative days 3, 5, and 14. Measurements of anastomotic bursting pressure were performed on days 3 and 5. At each time, collagen type I/III ratio, MMP 2 and MMP-9 expression and the proliferation index (Ki67) were analyzed.ResultsIn total, 90 animals underwent surgery without postoperative complications. Bursting strength in the GPVDF group was significantly elevated on day 5. Immunohistochemistry showed significant increase of the collagen type I/III ratio for PVDF and GPVDF on days 3 and 5. MMP2 was significantly increased for PVDF on days 3 and 5 and for GPVDF on day 5. The analysis of MMP9 revealed significant increase compared to control on day 3 and 5 (GPVDF) as well as on day 5 (PVDF). Staining for Ki67 revealed a significant elevation on postoperative day 3 for the PVDF and the GPVDF group.ConclusionsThe present data shows the feasibility of PVDF as suture material for colonic anastomosis and confirms the ability of gentamicin to increase the stability of colonic anastomosis when used as coating material.