Low back pain patients with Modic type 1 changes exhibit distinct bacterial and non-bacterial subtypes.

Objectives: Modic type 1 changes (MC1) are vertebral endplate bone marrow (BM) lesions observed on magnetic resonance images in sub-populations of chronic low back pain (CLBP) patients. The etiopathogenesis remains unknown and treatments that modify the underlying pathomechanisms do not exist. We hypothesized that two biological MC1 subtypes exist: a bacterial and a non-bacterial. This would have important implications for developing treatments targeting the underlying pathomechanisms. Methods: Intervertebral disc (IVD) samples adjacent to MC1 (n â€‹= â€‹34) and control (n â€‹= â€‹11) vertebrae were collected from patients undergoing spinal fusion. Cutibacterium acnes (C.acnes) genome copy numbers (GCNs) were quantified in IVD tissues with 16S qPCR, transcriptomic signatures and cytokine profiles were determined in MC1 and control BM by RNA sequencing and immunoassay. Finally, we assessed if C.acnes GCNs are associated with blood plasma cytokines. Results: IVD tissues from control levels had <870 â€‹C.acnes GCNs/gram IVD. MC1-adjacent IVDs had either "low" (<870) or "high" (>870) C.acnes GCNs. MC1 patients with "high" C.acnes GCNs had upregulated innate immune cell signatures (neutrophil, macrophage/monocyte) and pro-inflammatory cytokines related to neutrophil and macrophage/monocyte function in the BM, consistent with a host defense against bacterium. MC1 patients with "low" C.acnes GCNs had increased adaptive immune cell signatures (T-and B-cell) in the BM and elevated IL-13 blood plasma levels. Conclusion: Our study provides the first evidence for the existence of bacterial (C.acnes "high") and non-bacterial (C.acnes "low") subtypes in MC1 patients with CLBP. This supports the need for different treatment strategies.

An intensive care unit outbreak with multi-drug-resistant Pseudomonas aeruginosa - spotlight on sinks.

BACKGROUND: Pseudomonas aeruginosa and other Gram-negative bacteria have the ability to persist in moist environments in healthcare settings, but their spread from these areas can result in outbreaks of healthcare-associated infections. METHODS: This study reports the investigation and containment of a multi-drug-resistant P. aeruginosa outbreak in three intensive care units of a Swiss university hospital. In total, 255 patients and 276 environmental samples were screened for the multi-drug-resistant P. aeruginosa outbreak strain. The environmental sampling and molecular characterization of patient and environmental strains, and control strategies implemented, including waterless patient care, are described. RESULTS: Between March and November 2019, the outbreak affected 29 patients. Environmental sampling detected the outbreak strain in nine samples of sink siphons of three different intensive care units with a common water sewage system, and on one gastroscope. Three weeks after replacement of the sink siphons, the outbreak strain re-grew in siphon-derived samples and newly affected patients were identified. The outbreak ceased after removal of all sinks in the proximity of patients and in medication preparation areas, and minimization of tap water use. Multi-locus sequence typing indicated clonality (sequence type 316) in 28/29 patient isolates and all 10 environmental samples. CONCLUSIONS: Sink removal combined with the introduction of waterless patient care terminated the multi-drug-resistant P. aeruginosa outbreak. Sinks in intensive care units may pose a risk for point source outbreaks with P. aeruginosa and other bacteria persisting in moist environments.

Eye-tracking to observe compliance with hand hygiene in the intensive care unit: a randomized feasibility study.

BACKGROUND: Healthcare-associated infections are associated with increased patient mortality. Hand hygiene is the most effective method to reduce these infections. Despite simplification of this easy intervention, compliance with hand disinfection remains low. Current assessment of hand hygiene is mainly based on observation by hygiene specialists. The aim of this study was to investigate additional benefits of eye-tracking during the analysis of hand hygiene compliance of healthcare professionals in the intensive care unit. METHODS: In a simulated, randomized crossover study conducted at the interdisciplinary intensive care unit at University Hospital Zurich, Switzerland, doctors and nurses underwent eye-tracking and completed two everyday tasks (injection of 10 µg norepinephrine via a central venous line, blood removal from the central line) in two scenarios where the locations of alcoholic dispensers differed ('in-sight' and 'out-of-sight'). The primary outcomes were dwell time, revisits, first fixation duration and average fixation duration on three areas of interest (central venous line, alcohol dispenser, protective glove box) for both scenarios. Compliance with hand hygiene guidelines was analysed. FINDINGS: Forty-nine participants (35 nurses, 14 doctors) were included in this study. Eye-tracking provided additional useful information compared with conventional observations. Dwell time, revisits, first fixation duration and average fixation duration did not differ between the two scenarios for all areas of interest. Overall compliance with recommended hand hygiene measures was low in both doctors (mean 20%) and nurses (mean 42.9%). CONCLUSION: Compared with conventional observations, eye-tracking offered additional helpful insights and provided an in-depth analysis of gaze patterns during the recording of hand hygiene compliance in the intensive care unit.

FGF2 overrides key pro-fibrotic features of bone marrow stromal cells isolated from Modic type 1 change patients.

Extensive extracellular matrix production and increased cell-matrix adhesion by bone marrow stromal cells (BMSCs) are hallmarks of fibrotic alterations in the vertebral bone marrow known as Modic type 1 changes (MC1). MC1 are associated with non-specific chronic low-back pain. To identify treatment targets for MC1, in vitro studies using patient BMSCs are important to reveal pathological mechanisms. For the culture of BMSCs, fibroblast growth factor 2 (FGF2) is widely used. However, FGF2 has been shown to suppress matrix synthesis in various stromal cell populations. The aim of the present study was to investigate whether FGF2 affected the in vitro study of the fibrotic pathomechanisms of MC1-derived BMSCs. Transcriptomic changes and changes in cell-matrix adhesion of MC1-derived BMSCs were compared to intra-patient control BMSCs in response to FGF2. RNA sequencing and quantitative real-time polymerase chain reaction revealed that pro-fibrotic genes and pathways were not detectable in MC1-derived BMSCs when cultured in the presence of FGF2. In addition, significantly increased cell-matrix adhesion of MC1-derived BMSCs was abolished in the presence of FGF2. In conclusion, the data demonstrated that FGF2 overrides key pro-fibrotic features of MC1 BMSCs in vitro. Usage of FGF2-supplemented media in studies of fibrotic mechanisms should be critically evaluated as it could override normally dominant biological and biophysical cues.

Pro-fibrotic phenotype of bone marrow stromal cells in Modic type 1 changes.

Modic type 1 changes (MC1) are painful vertebral bone marrow lesions frequently found in patients suffering from chronic low-back pain. Marrow fibrosis is a hallmark of MC1. Bone marrow stromal cells (BMSCs) are key players in other fibrotic bone marrow pathologies, yet their role in MC1 is unknown. The present study aimed to characterise MC1 BMSCs and hypothesised a pro-fibrotic role of BMSCs in MC1. BMSCs were isolated from patients undergoing lumbar spinal fusion from MC1 and adjacent control vertebrae. Frequency of colony-forming unit fibroblast (CFU-F), expression of stem cell surface markers, differentiation capacity, transcriptome, matrix adhesion, cell contractility as well as expression of pro-collagen type I alpha 1, α-smooth muscle actin, integrins and focal adhesion kinase (FAK) were compared. More CFU-F and increased expression of C-X-C-motif-chemokine 12 were found in MC1 BMSCs, possibly indicating overrepresentation of a perisinusoidal BMSC population. RNA sequencing analysis showed enrichment in extracellular matrix proteins and fibrosis-related signalling genes. Increases in pro-collagen type I alpha 1 expression, cell adhesion, cell contractility and phosphorylation of FAK provided further evidence for their pro-fibrotic phenotype. Moreover, a leptin receptor high expressing (LEPRhigh) BMSC population was identified that differentiated under transforming growth factor beta 1 stimulation into myofibroblasts in MC1 but not in control BMSCs. In conclusion, pro-fibrotic changes in MC1 BMSCs and a LEPRhigh MC1 BMSC subpopulation susceptible to myofibroblast differentiation were found. Fibrosis is a hallmark of MC1 and a potential therapeutic target. A causal link between the pro-fibrotic phenotype and clinical characteristics needs to be demonstrated.

Protease-activated receptor-1 cleaved at R46 mediates cytoprotective effects.

BACKGROUND: Activated protein C (aPC) mediates powerful cytoprotective effects through the protease-activated receptor-1 (PAR1) that translate into reduced harm in mouse injury models. However, it remains elusive how aPC-activated PAR1 can mediate cytoprotective effects whereas thrombin activation does the opposite. OBJECTIVES: We hypothesized that aPC and thrombin might induce distinct active conformations in PAR1 causing opposing effects. METHODS: We analyzed antibody binding to, and cleavage and signalling of PAR1 in either endogenously expressing endothelial or overexpressing 293T cells. RESULTS: In thrombin-cleaved PAR1 neither the tethered ligand nor the hirudin-like domain were available for anti-PAR1 ATAP2 and WEDE15 binding unless the tethered ligand was quenched. In contrast, aPC irreversibly prevented ATAP2 binding while not affecting WEDE15 binding. Reporter constructs with selective glutamine substitutions confirmed R41 as the only thrombin cleavage site in PAR1, whereas aPC preferentially cleaved at R46. Similarly, we report distinct cleavage sites on PAR3, K38 for thrombin and R41 for aPC. A soluble peptide corresponding to R46-cleaved PAR1 enhanced the endothelial barrier function and reduced staurosporine toxicity in endothelial as well as in 293T cells if PAR1 was expressed. Overexpression of PAR1 variants demonstrated that cleavage at R46 but not R41 is required for cytoprotective aPC signaling. CONCLUSIONS: We provide a novel concept on how aPC and thrombin mediate distinct effects. We propose that the enzyme-specific cleavage sites induce specific conformations which mediate divergent downstream effects. This unexpected model of PAR1 signaling might lead to novel therapeutic options for the treatment of inflammatory diseases.

Coagulation factor Xa cleaves protease-activated receptor-1 and mediates signaling dependent on binding to the endothelial protein C receptor.

BACKGROUND AND OBJECTIVE: Coagulation is intrinsically tied to inflammation, and both proinflammatory and anti-inflammatory responses are modulated by coagulation protease signaling through protease-activated receptor-1 (PAR1). Activated factor X (FXa) can elicit cellular signaling through PAR1, but little is known about the role of cofactors in this pathway. Endothelial protein C receptor (EPCR) supports PAR1 signaling by the protein C pathway, and in the present study we tested whether EPCR mediates surface recruitment and signaling of FXa. METHODS AND RESULTS: Here, we show that FXa binds to overexpressed as well as native endothelial EPCR. PAR1 cleavage by FXa as analyzed with conformation-sensitive antibodies and a tagged PAR1 reporter construct was strongly enhanced if EPCR was available. Anti-EPCR failed to affect the tissue factor-dependent activation of FX, but high concentrations of FXa decreased EPCR-dependent protein C activation. Most importantly, the FXa-mediated induction of Erk1/2 activation, expression of the transcript for connective tissue growth factor and barrier protection in endothelial cells required binding to EPCR. CONCLUSIONS: Our results demonstrate that EPCR plays an unexpected role in supporting cell surface recruitment, PAR1 activation, and signaling by FXa.

Indications and impact of postoperative transesophageal echocardiography in cardiac surgical patients.

OBJECTIVE: Transesophageal echocardiography (TEE) has gained widespread acceptance among intensivists as a tool to facilitate decision-making in the management of critically ill patients. This observational study analyzes the indications and impact of TEE and the outcome in patients following cardiac surgery. DESIGN: Standardized reports containing indication, main diagnosis, and impact on patient management were completed during TEE. SETTING: Intensive care unit in a university hospital. PATIENTS: Postoperative cardiac surgery patients requiring TEE. INTERVENTION: TEE in sedated and mechanically ventilated patients. MEASUREMENTS AND RESULTS: Reports were obtained in 301 adult patients between June 1996 and June 2000. Indications were postoperative control of left ventricular function in 102 (34%) cases; unexplained, sudden hemodynamic deterioration in 89 (29%); suspicion of pericardial tamponade in 41 (14%); cardiac ischemia in 26 (9%); and "other" in 43 (14%). In 136 patients (45%), a new diagnosis was established or an important pathology was excluded. Pericardial tamponade was diagnosed in 34 cases (11%) and excluded in 36 cases (12%). Other diagnoses included severe left ventricular failure, large pleural effusion, and others. Therapeutic impact was found in 220 cases (73%): change of pharmacologic treatment and/or fluid therapy in 118 cases (40%), resternotomy in 43 (14%), no reoperation necessary in 39 (13%), and various in 20 (7%). No impact was found in 81 cases (27%). In a subgroup of patients in whom preoperative risk scores were evaluated, the indication for a postoperative TEE was significantly associated with a prolonged stay in the intensive care unit: 7 (5.6, 8.4) days vs. 1 (0.8, 1.2) day (median, [95% confidence interval]) (p <.0001), more neurologic complications (18/137 = 13.1% vs. 21/680 = 3.0%) (p <.0001), and increased mortality (34/153 = 22.2% vs. 18/709 = 2.5%) (p <.0001). Corrected for preoperative risk scores, these differences were still significant. CONCLUSION: Although TEE provided important findings and therapeutic impact in postoperative cardiac surgical patients, patients with comparable preoperative risk who had postoperative TEE examinations had a significantly worse outcome than those without the need for postoperative TEE.