1
|
Näf L, Miescher I, Pfuderer L, Schweizer TA, Brunner D, Dürig J, Gröninger O, Rieber J, Meier-Buergisser G, Spanaus K, Calcagni M, Bosshard PP, Achermann Y, Stark WJ, Buschmann J. Pro-angiogenic and antibacterial copper containing nanoparticles in PLGA/amorphous calcium phosphate bone nanocomposites. Heliyon 2024; 10:e27267. [PMID: 38486752 PMCID: PMC10937708 DOI: 10.1016/j.heliyon.2024.e27267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 02/27/2024] [Indexed: 03/17/2024] Open
Abstract
Large bone defects after trauma demand for adequate bone substitutes. Bone void fillers should be antibacterial and pro-angiogenic. One viable option is the use of composite materials like the combination of PLGA and amorphous calcium phosphate (aCaP). Copper stimulates angiogenesis and has antibacterial qualities. Either copper oxide (CuO) nanoparticles (NPs) were therefore added to PLGA/aCaP/CuO in different concentrations (1, 5 and 10 w/w %) or copper-doped tricalcium phosphate NPs (TCP with 2% of copper) were electrospun into PLGA/CuTCP nanocomposites. Bi-layered nanocomposites of PLGA/aCaP with different copper NPs (CuO or TCP) and a second layer of pristine PLGA were fabricated. Two clinical bacterial isolates (Staphylococcus aureus and Staphylococcus epidermidis) were used to assess antibacterial properties of the copper-containing materials. For angiogenesis, the chorioallantoic membrane (CAM) assay of the chicken embryo was performed. The higher the CuO content, the higher were the antibacterial properties, with 10 % CuO reducing bacterial adhesion most effectively. Vessel and cell densities were highest in the 5 % CuO containing scaffolds, while tissue integration was more pronounced at lower CuO content. The PLGA/aCaP/CuO (1 % CuO) behaved similar like PLGA/CuTCP in all angiogenic and antibacterial readouts, based on the same copper fraction. We conclude that CuO NPs or CuTCP NPs are useful components to increase angiogenic properties of nanocomposites and at the same time exhibiting antibacterial characteristics.
Collapse
Affiliation(s)
- Lukas Näf
- Department of Plastic Surgery and Hand Surgery, University Hospital of Zürich, Rämistrasse 100, 8091, Zürich, Switzerland
| | - Iris Miescher
- Department of Plastic Surgery and Hand Surgery, University Hospital of Zürich, Rämistrasse 100, 8091, Zürich, Switzerland
| | - Lara Pfuderer
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Tiziano A. Schweizer
- Department of Dermatology, University Hospital Zurich, University of Zurich, Rämistrasse 100, 8091, Zurich, Switzerland
| | - David Brunner
- Department of Plastic Surgery and Hand Surgery, University Hospital of Zürich, Rämistrasse 100, 8091, Zürich, Switzerland
| | - Johannes Dürig
- Department of Plastic Surgery and Hand Surgery, University Hospital of Zürich, Rämistrasse 100, 8091, Zürich, Switzerland
| | - Olivier Gröninger
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Julia Rieber
- Department of Plastic Surgery and Hand Surgery, University Hospital of Zürich, Rämistrasse 100, 8091, Zürich, Switzerland
| | - Gabriella Meier-Buergisser
- Department of Plastic Surgery and Hand Surgery, University Hospital of Zürich, Rämistrasse 100, 8091, Zürich, Switzerland
| | - Katharina Spanaus
- Clinical Chemistry, University Hospital Zurich, 8001, Zurich, Switzerland
| | - Maurizio Calcagni
- Department of Plastic Surgery and Hand Surgery, University Hospital of Zürich, Rämistrasse 100, 8091, Zürich, Switzerland
| | - Philipp P. Bosshard
- Department of Dermatology, University Hospital Zurich, University of Zurich, Rämistrasse 100, 8091, Zurich, Switzerland
| | - Yvonne Achermann
- Department of Dermatology, University Hospital Zurich, University of Zurich, Rämistrasse 100, 8091, Zurich, Switzerland
| | - Wendelin J. Stark
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Johanna Buschmann
- Department of Plastic Surgery and Hand Surgery, University Hospital of Zürich, Rämistrasse 100, 8091, Zürich, Switzerland
| |
Collapse
|
2
|
Deplazes BC, Hofmaenner DA, Scheier TC, Epprecht J, Mayer M, Schweizer TA, Buehler PK, Frey PM, Brugger SD. Enzymatic debridement with bromelain and development of bacteremia in burn injuries: A retrospective cohort study. Burns 2024; 50:405-412. [PMID: 38182450 DOI: 10.1016/j.burns.2023.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 11/12/2023] [Accepted: 12/07/2023] [Indexed: 01/07/2024]
Abstract
BACKGROUND Debridement is crucial for effective wound management in patients with severe burn injuries, and bromelain, a proteolytic enzyme from pineapple stems, has emerged as a promising alternative for surgery. However, potential links of bromelain use to fever and sepsis have raised some concerns. Given the uncertainty as to whether this was caused by infection or other inflammatory sources, we aimed to investigate if the use of topical bromelain was associated with bacteremia. METHODS This single-centre retrospective cohort study included critically ill adult patients with severe burn injuries hospitalised at the Burn Center of the University Hospital Zurich between January 2017 and December 2021. Data were collected from two in-hospital electronic medical records databases. Our primary outcome, the association between topical bromelain treatment and the development of bacteremia, was investigated using a competing risk regression model, taking into account the competing risk of death. As a secondary outcome, the relationship between bromelain treatment and overall ICU mortality was examined using a Cox proportional hazards model. RESULTS The study included 269 patients with a median age of 50 years and median burnt total body surface area of 19%. A first bacteremia occurred in 61 patients (23%) after a median time of 6 days. Bromelain treatment was given to 83 (31%) of patients, with 22 (27%) of these developing bacteremia. In the fully adjusted competing risk regression model, no evidence for an association between bromelain treatment and bacteremia was found (SHR 0.79, 95%CI 0.42-1.48, p = 0.47). During hospital stay, 40 (15%) of patients died. There was no significant difference in mortality between patients treated with bromelain and those who were not (HR 0.55, 95%CI 0.26-1.20, p = 0.14). Among the five multidrug-resistant (MDR) pathogens identified, three were found in patients with bromelain treatment. CONCLUSION Our study did not confirm an association between topical bromelain and bacteremia in patients with severe burn injuries. This finding can inform evidence-based practices by addressing concerns about potential risks of bromelain use, contributing to the development of more effective and safe burn wound management strategies.
Collapse
Affiliation(s)
- Barla C Deplazes
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Daniel A Hofmaenner
- Institute of Intensive Care Medicine, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Thomas C Scheier
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Jana Epprecht
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Michelle Mayer
- Institute of Intensive Care Medicine, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Tiziano A Schweizer
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Philipp K Buehler
- Department of Intensive Care Medicine, Cantonal Hospital Winterthur, Winterthur, Switzerland
| | - Pascal M Frey
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland; Department of General Internal Medicine, Bern University Hospital, Inselspital, University of Bern, Bern, Switzerland.
| | - Silvio D Brugger
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| |
Collapse
|
3
|
Roehrig C, Huemer M, Lorgé D, Arn F, Heinrich N, Selvakumar L, Gasser L, Hauswirth P, Chang CC, Schweizer TA, Eichenseher F, Lehmann S, Zinkernagel AS, Schmelcher M. MEndoB, a chimeric lysin featuring a novel domain architecture and superior activity for the treatment of staphylococcal infections. mBio 2024; 15:e0254023. [PMID: 38275913 PMCID: PMC10865858 DOI: 10.1128/mbio.02540-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 12/14/2023] [Indexed: 01/27/2024] Open
Abstract
Bacterial infections are a growing global healthcare concern, as an estimated annual 4.95 million deaths are associated with antimicrobial resistance (AMR). Methicillin-resistant Staphylococcus aureus is one of the deadliest pathogens and a high-priority pathogen according to the World Health Organization. Peptidoglycan hydrolases (PGHs) of phage origin have been postulated as a new class of antimicrobials for the treatment of bacterial infections, with a novel mechanism of action and no known resistances. The modular architecture of PGHs permits the creation of chimeric PGH libraries. In this study, the chimeric enzyme MEndoB was selected from a library of staphylococcal PGHs based on its rapid and sustained activity against staphylococci in human serum. The benefit of the presented screening approach was illustrated by the superiority of MEndoB in a head-to-head comparison with other PGHs intended for use against staphylococcal bacteremia. MEndoB displayed synergy with antibiotics and rapid killing in human whole blood with complete inhibition of re-growth over 24 h at low doses. Successful treatment of S. aureus-infected zebrafish larvae with MEndoB provided evidence for its in vivo effectiveness. This was further confirmed in a lethal systemic mouse infection model in which MEndoB significantly reduced S. aureus loads and tumor necrosis factor alpha levels in blood in a dose-dependent manner, which led to increased survival of the animals. Thus, the thorough lead candidate selection of MEndoB resulted in an outstanding second-generation PGH with in vitro, ex vivo, and in vivo results supporting further development.IMPORTANCEOne of the most pressing challenges of our era is the rising occurrence of bacteria that are resistant to antibiotics. Staphylococci are prominent pathogens in humans, which have developed multiple strategies to evade the effects of antibiotics. Infections caused by these bacteria have resulted in a high burden on the health care system and a significant loss of lives. In this study, we have successfully engineered lytic enzymes that exhibit an extraordinary ability to eradicate staphylococci. Our findings substantiate the importance of meticulous lead candidate selection to identify therapeutically promising peptidoglycan hydrolases with unprecedented activity. Hence, they offer a promising new avenue for treating staphylococcal infections.
Collapse
Affiliation(s)
- Christian Roehrig
- Micreos Pharmaceuticals AG, Baar, Zug, Switzerland
- Micreos GmbH, Wädenswil, Zurich, Switzerland
| | | | | | | | | | | | - Lynn Gasser
- Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences (ZHAW), Wädenswil, Zurich, Switzerland
| | - Patrick Hauswirth
- Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences (ZHAW), Wädenswil, Zurich, Switzerland
| | - Chun-Chi Chang
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Tiziano A. Schweizer
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | | | - Steffi Lehmann
- Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences (ZHAW), Wädenswil, Zurich, Switzerland
| | - Annelies S. Zinkernagel
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | | |
Collapse
|
4
|
Miescher I, Rieber J, Schweizer TA, Orlietti M, Tarnutzer A, Andreoni F, Meier Buergisser G, Giovanoli P, Calcagni M, Snedeker JG, Zinkernagel AS, Buschmann J. In Vitro Assessment of Bacterial Adhesion and Biofilm Formation on Novel Bioactive, Biodegradable Electrospun Fiber Meshes Intended to Support Tendon Rupture Repair. ACS Appl Mater Interfaces 2024; 16:6348-6355. [PMID: 38288645 DOI: 10.1021/acsami.3c15710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
The surgical repair of a ruptured tendon faces two major problems: specifically increased fibrous adhesion to the surrounding tissue and inferior mechanical properties of the scar tissue compared to the native tissue. Bacterial attachment to implant materials is an additional problem as it might lead to severe infections and impaired recovery. To counteract adhesion formation, two novel implant materials were fabricated by electrospinning, namely, a random fiber mesh containing hyaluronic acid (HA) and poly(ethylene oxide) (PEO) in a ratio of 1:1 (HA/PEO 1:1) and 1:4 (HA/PEO 1:4), respectively. Electrospun DegraPol (DP) treated with silver nanoparticles (DP-Ag) was developed to counteract the bacterial attachment. The three novel materials were compared to the previously described DP and DP with incorporated insulin-like growth factor-1 (DP-IGF-1), two implant materials that were also designed to improve tendon repair. To test whether the materials are prone to bacterial adhesion and biofilm formation, we assessed 10 strains of Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Enterococcus faecalis, known for causing nosocomial infections. Fiber diameter, pore size, and water contact angle, reflecting different degrees of hydrophobicity, were used to characterize all materials. Generally, we observed higher biofilm formation on the more hydrophobic DP as compared to the more hydrophilic DP-IGF-1 and a trend toward reduced biofilm formation for DP treated with silver nanoparticles. For the two HA/PEO implants, a similar biofilm formation was observed. All tested materials were highly prone to bacterial adherence and biofilm formation, pointing toward the need of further material development, including the optimized incorporation of antibacterial agents such as silver nanoparticles or antibiotics.
Collapse
Affiliation(s)
- Iris Miescher
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Julia Rieber
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Tiziano A Schweizer
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Rämistrasse 100, 8091 Zurich, Switzerland
- Department of Dermatology, University Hospital Zurich, University of Zurich, Rämistrasse 100, 8091 Zurich, Switzerland
| | - Mariano Orlietti
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Rämistrasse 100, 8091 Zurich, Switzerland
| | - Andrea Tarnutzer
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Rämistrasse 100, 8091 Zurich, Switzerland
| | - Federica Andreoni
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Rämistrasse 100, 8091 Zurich, Switzerland
| | - Gabriella Meier Buergisser
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Pietro Giovanoli
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Maurizio Calcagni
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Jess G Snedeker
- Laboratory for Orthopedic Biomechanics, Department of Orthopedics, University of Zurich, Lengghalde 5, 8008 Zurich, Switzerland
| | - Annelies S Zinkernagel
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Rämistrasse 100, 8091 Zurich, Switzerland
| | - Johanna Buschmann
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| |
Collapse
|
5
|
Räz AK, Andreoni F, Boumasmoud M, Bergada-Pijuan J, Schweizer TA, Mairpady Shambat S, Hasse B, Zinkernagel AS, Brugger SD. Limited Adaptation of Staphylococcus aureus during Transition from Colonization to Invasive Infection. Microbiol Spectr 2023; 11:e0259021. [PMID: 37341598 PMCID: PMC10433843 DOI: 10.1128/spectrum.02590-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 05/24/2023] [Indexed: 06/22/2023] Open
Abstract
Staphylococcus aureus carriage is a risk factor for invasive infections. Unique genetic elements favoring the transition from colonizing to invasive phenotype have not yet been identified, and phenotypic adaptation traits are understudied. We therefore assessed phenotypic and genotypic profiles of 11 S. aureus isolate pairs sampled from colonized patients simultaneously suffering from invasive S. aureus infections. Ten out of 11 isolate pairs displayed the same spa and multilocus sequence type, suggesting colonization as an origin for the invasive infection. Systematic analysis of colonizing and invasive isolate pairs showed similar adherence, hemolysis, reproductive fitness properties, antibiotic tolerance, and virulence in a Galleria mellonella infection model, as well as minimal genetic differences. Our results provide insights into the similar phenotypes associated with limited adaptation between colonizing and invasive isolates. Disruption of the physical barriers of mucosa or skin was identified in the majority of patients, further emphasizing colonization as a major risk factor for invasive disease. IMPORTANCE S. aureus is a major pathogen of humans, causing a wide range of diseases. The difficulty to develop a vaccine and antibiotic treatment failure warrant the exploration of novel treatment strategies. Asymptomatic colonization of the human nasal passages is a major risk factor for invasive disease, and decolonization procedures have been effective in preventing invasive infections. However, the transition of S. aureus from a benign colonizer of the nasal passages to a major pathogen is not well understood, and both host and bacterial properties have been discussed as being relevant for this behavioral change. We conducted a thorough investigation of patient-derived strain pairs reflecting colonizing and invasive isolates in a given patient. Although we identified limited genetic adaptation in certain strains, as well as slight differences in adherence capacity among colonizing and invasive isolates, our work suggests that barrier breaches are a key event in the disease continuum of S. aureus.
Collapse
Affiliation(s)
- Anna K. Räz
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Federica Andreoni
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Mathilde Boumasmoud
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Judith Bergada-Pijuan
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Tiziano A. Schweizer
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Srikanth Mairpady Shambat
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Barbara Hasse
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Annelies S. Zinkernagel
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Silvio D. Brugger
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| |
Collapse
|
6
|
Schweizer TA, Hertegonne S, Vulin C, Zinkernagel AS, Mairpady Shambat S. Antibacterial Neutrophil Effector Response: Ex Vivo Quantification of Regulated Cell Death Associated with Extracellular Trap Release. Methods Mol Biol 2023; 2674:235-250. [PMID: 37258972 DOI: 10.1007/978-1-0716-3243-7_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Regulated cell death (RCD) and the concomitant release of extracellular traps by neutrophils (NETs) constitute an important antibacterial effector response. Usually, the dynamic processes of RCD and NETs release are assessed independently of each other by either unspecific or time-consuming methods. Here, we describe a flow cytometry-based high-throughput analysis method incorporating neutrophil RCD and NETs release with visual live-imaging conformation upon ex vivo bacterial challenge. This combined approach allows to quantify and closely follow the kinetics of the dynamic neutrophil effector response towards bacterial infection.
Collapse
Affiliation(s)
- Tiziano A Schweizer
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Sanne Hertegonne
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Clément Vulin
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Annelies S Zinkernagel
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Srikanth Mairpady Shambat
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich and University of Zurich, Zurich, Switzerland.
| |
Collapse
|
7
|
Schweizer TA, Andreoni F, Acevedo C, Scheier TC, Heggli I, Maggio EM, Eberhard N, Brugger SD, Dudli S, Zinkernagel AS. Intervertebral disc cell chondroptosis elicits neutrophil response in Staphylococcus aureus spondylodiscitis. Front Immunol 2022; 13:908211. [PMID: 35967370 PMCID: PMC9366608 DOI: 10.3389/fimmu.2022.908211] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 07/06/2022] [Indexed: 11/13/2022] Open
Abstract
To understand the pathophysiology of spondylodiscitis due to Staphylococcus aureus, an emerging infectious disease of the intervertebral disc (IVD) and vertebral body with a high complication rate, we combined clinical insights and experimental approaches. Clinical data and histological material of nine patients suffering from S. aureus spondylodiscitis were retrospectively collected at a single center. To mirror the clinical findings experimentally, we developed a novel porcine ex vivo model mimicking acute S. aureus spondylodiscitis and assessed the interaction between S. aureus and IVD cells within their native environment. In addition, the inflammatory features underlying this interaction were assessed in primary human IVD cells. Finally, mirroring the clinical findings, we assessed primary human neutrophils for their ability to respond to secreted inflammatory modulators of IVD cells upon the S. aureus challenge. Acute S. aureus spondylodiscitis in patients was characterized by tissue necrosis and neutrophil infiltration. Additionally, the presence of empty IVD cells’ lacunae was observed. This was mirrored in the ex vivo porcine model, where S. aureus induced extensive IVD cell death, leading to empty lacunae. Concomitant engagement of the apoptotic and pyroptotic cell death pathways was observed in primary human IVD cells, resulting in cytokine release. Among the released cytokines, functionally intact neutrophil-priming as well as broad pro- and anti-inflammatory cytokines which are known for their involvement in IVD degeneration were found. In patients as well as ex vivo in a novel porcine model, S. aureus IVD infection caused IVD cell death, resulting in empty lacunae, which was accompanied by the release of inflammatory markers and recruitment of neutrophils. These findings offer valuable insights into the important role of inflammatory IVD cell death during spondylodiscitis and potential future therapeutic approaches.
Collapse
Affiliation(s)
- Tiziano A. Schweizer
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Federica Andreoni
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Claudio Acevedo
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Thomas C. Scheier
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Irina Heggli
- Center of Experimental Rheumatology, University Hospital Zurich and Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Department of Physical Medicine and Rheumatology, University Hospital Zurich and Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Ewerton Marques Maggio
- Department of Pathology and Molecular Pathology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Nadia Eberhard
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Silvio D. Brugger
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Stefan Dudli
- Center of Experimental Rheumatology, University Hospital Zurich and Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Center for Applied Biotechnology and Molecular Medicine (CABMM), University of Zurich, Zurich, Switzerland
| | - Annelies S. Zinkernagel
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Center for Applied Biotechnology and Molecular Medicine (CABMM), University of Zurich, Zurich, Switzerland
- *Correspondence: Annelies S. Zinkernagel,
| |
Collapse
|
8
|
Boumasmoud M, Dengler Haunreiter V, Schweizer TA, Meyer L, Chakrakodi B, Schreiber PW, Seidl K, Kühnert D, Kouyos RD, Zinkernagel AS. Genomic Surveillance of Vancomycin-Resistant Enterococcus faecium Reveals Spread of a Linear Plasmid Conferring a Nutrient Utilization Advantage. mBio 2022; 13:e0377121. [PMID: 35343787 PMCID: PMC9040824 DOI: 10.1128/mbio.03771-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 02/25/2022] [Indexed: 12/12/2022] Open
Abstract
Healthcare-associated outbreaks of vancomycin-resistant Enterococcus faecium (VREfm) are a worldwide problem with increasing prevalence. The genomic plasticity of this hospital-adapted pathogen contributes to its efficient spread despite infection control measures. Here, we aimed to identify the genomic and phenotypic determinants of health care-associated transmission of VREfm. We assessed the VREfm transmission networks at the tertiary-care University Hospital of Zurich (USZ) between October 2014 and February 2018 and investigated microevolutionary dynamics of this pathogen. We performed whole-genome sequencing for the 69 VREfm isolates collected during this time frame and assessed the population structure and variability of the vancomycin resistance transposon. Phylogenomic analysis allowed us to reconstruct transmission networks and to unveil external or wider transmission networks undetectable by routine surveillance. Notably, it unveiled a persistent clone, sampled 31 times over a 29-month period. Exploring the evolutionary dynamics of this clone and characterizing the phenotypic consequences revealed the spread of a variant with decreased daptomycin susceptibility and the acquired ability to utilize N-acetyl-galactosamine (GalNAc), one of the primary constituents of the human gut mucins. This nutrient utilization advantage was conferred by a novel plasmid, termed pELF_USZ, which exhibited a linear topology. This plasmid, which was harbored by two distinct clones, was transferable by conjugation. Overall, this work highlights the potential of combining epidemiological, functional genomic, and evolutionary perspectives to unveil adaptation strategies of VREfm. IMPORTANCE Sequencing microbial pathogens causing outbreaks has become a common practice to characterize transmission networks. In addition to the signal provided by vertical evolution, bacterial genomes harbor mobile genetic elements shared horizontally between clones. While macroevolutionary studies have revealed an important role of plasmids and genes encoding carbohydrate utilization systems in the adaptation of Enterococcus faecium to the hospital environment, mechanisms of dissemination and the specific function of many of these genetic determinants remain to be elucidated. Here, we characterize a plasmid providing a nutrient utilization advantage and show evidence for its clonal and horizontal spread at a local scale. Further studies integrating epidemiological, functional genomics, and evolutionary perspectives will be critical to identify changes shaping the success of this pathogen.
Collapse
Affiliation(s)
- Mathilde Boumasmoud
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Vanina Dengler Haunreiter
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Tiziano A. Schweizer
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Lilly Meyer
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Bhavya Chakrakodi
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Peter W. Schreiber
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Kati Seidl
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Denise Kühnert
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Roger D. Kouyos
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Annelies S. Zinkernagel
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| |
Collapse
|
9
|
Bär J, Boumasmoud M, Mairpady Shambat S, Vulin C, Huemer M, Schweizer TA, Gómez-Mejia A, Eberhard N, Achermann Y, Zingg PO, Mestres C, Brugger SD, Schuepbach RA, Kouyos RD, Hasse B, Zinkernagel AS. Quantification of within-patient Staphylococcus aureus phenotypic heterogeneity as a proxy for presence of persisters across clinical presentations. Clin Microbiol Infect 2022; 28:1022.e1-1022.e7. [DOI: 10.1016/j.cmi.2022.01.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 01/19/2022] [Accepted: 01/23/2022] [Indexed: 12/21/2022]
|
10
|
Mairpady Shambat S, Gómez-Mejia A, Schweizer TA, Huemer M, Chang CC, Acevedo C, Bergada-Pijuan J, Vulin C, Hofmaenner DA, Scheier TC, Hertegonne S, Parietti E, Miroshnikova N, Wendel Garcia PD, Hilty MP, Buehler PK, Schuepbach RA, Brugger SD, Zinkernagel AS. Hyperinflammatory environment drives dysfunctional myeloid cell effector response to bacterial challenge in COVID-19. PLoS Pathog 2022; 18:e1010176. [PMID: 35007290 PMCID: PMC8782468 DOI: 10.1371/journal.ppat.1010176] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 01/21/2022] [Accepted: 12/06/2021] [Indexed: 02/06/2023] Open
Abstract
COVID-19 displays diverse disease severities and symptoms including acute systemic inflammation and hypercytokinemia, with subsequent dysregulation of immune cells. Bacterial superinfections in COVID-19 can further complicate the disease course and are associated with increased mortality. However, there is limited understanding of how SARS-CoV-2 pathogenesis and hypercytokinemia impede the innate immune function against bacterial superinfections. We assessed the influence of COVID-19 plasma hypercytokinemia on the functional responses of myeloid immune cells upon bacterial challenges from acute-phase COVID-19 patients and their corresponding recovery-phase. We show that a severe hypercytokinemia status in COVID-19 patients correlates with the development of bacterial superinfections. Neutrophils and monocytes derived from COVID-19 patients in their acute-phase showed an impaired intracellular microbicidal capacity upon bacterial challenges. The impaired microbicidal capacity was reflected by abrogated MPO and reduced NETs production in neutrophils along with reduced ROS production in both neutrophils and monocytes. Moreover, we observed a distinct pattern of cell surface receptor expression on both neutrophils and monocytes, in line with suppressed autocrine and paracrine cytokine signaling. This phenotype was characterized by a high expression of CD66b, CXCR4 and low expression of CXCR1, CXCR2 and CD15 in neutrophils and low expression of HLA-DR, CD86 and high expression of CD163 and CD11b in monocytes. Furthermore, the impaired antibacterial effector function was mediated by synergistic effect of the cytokines TNF-α, IFN-γ and IL-4. COVID-19 patients receiving dexamethasone showed a significant reduction of overall inflammatory markers in the plasma as well as exhibited an enhanced immune response towards bacterial challenge ex vivo. Finally, broad anti-inflammatory treatment was associated with a reduction in CRP, IL-6 levels as well as length of ICU stay and ventilation-days in critically ill COVID-19 patients. Our data provides insights into the transient functional dysregulation of myeloid immune cells against subsequent bacterial infections in COVID-19 patients and describe a beneficial role for the use of dexamethasone in these patients.
Collapse
Affiliation(s)
- Srikanth Mairpady Shambat
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Alejandro Gómez-Mejia
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Tiziano A. Schweizer
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Markus Huemer
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Chun-Chi Chang
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Claudio Acevedo
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Judith Bergada-Pijuan
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Clément Vulin
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Daniel A. Hofmaenner
- Institute of Intensive Care, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Thomas C. Scheier
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Sanne Hertegonne
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Elena Parietti
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Nataliya Miroshnikova
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Pedro D. Wendel Garcia
- Institute of Intensive Care, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Matthias P. Hilty
- Institute of Intensive Care, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Philipp Karl Buehler
- Institute of Intensive Care, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Reto A. Schuepbach
- Institute of Intensive Care, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Silvio D. Brugger
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Annelies S. Zinkernagel
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| |
Collapse
|
11
|
Schweizer TA, Mairpady Shambat S, Vulin C, Hoeller S, Acevedo C, Huemer M, Gomez‐Mejia A, Chang C, Baum J, Hertegonne S, Hitz E, Scheier TC, Hofmaenner DA, Buehler PK, Moch H, Schuepbach RA, Brugger SD, Zinkernagel AS. Blunted sFasL signalling exacerbates TNF-driven neutrophil necroptosis in critically ill COVID-19 patients. Clin Transl Immunology 2021; 10:e1357. [PMID: 34938538 PMCID: PMC8665925 DOI: 10.1002/cti2.1357] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 10/26/2021] [Accepted: 11/03/2021] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVES Critically ill coronavirus disease 2019 (COVID-19) patients are characterised by a severely dysregulated cytokine profile and elevated neutrophil counts, impacting disease severity. However, it remains unclear how neutrophils contribute to pathophysiology during COVID-19. Here, we assessed the impact of the dysregulated cytokine profile on the regulated cell death (RCD) programme of neutrophils. METHODS Regulated cell death phenotype of neutrophils isolated from critically ill COVID-19 patients or healthy donors and stimulated with COVID-19 or healthy plasma ex vivo was assessed by flow cytometry, time-lapse microscopy and cytokine multiplex analysis. Immunohistochemistry of COVID-19 patients and control biopsies were performed to assess the in situ neutrophil RCD phenotype. Plasma cytokine levels of COVID-19 patients and healthy donors were measured by multiplex analysis. Clinical parameters were correlated to cytokine levels of COVID-19 patients. RESULTS COVID-19 plasma induced a necroptosis-sensitive neutrophil phenotype, characterised by cell lysis, elevated release of damage-associated molecular patterns (DAMPs), increased receptor-interacting serine/threonine-protein kinase (RIPK) 1 levels and mixed lineage kinase domain-like pseudokinase (MLKL) involvement. The occurrence of neutrophil necroptosis MLKL axis was further confirmed in COVID-19 thrombus and lung biopsies. Necroptosis was induced by the tumor necrosis factor receptor 1 (TNFRI)/TNF-α axis. Moreover, reduction of soluble Fas ligand (sFasL) levels in COVID-19 patients and hence decreased signalling to Fas directly increased RIPK1 levels, exacerbated TNF-driven necroptosis and correlated with disease severity, which was abolished in patients treated with glucocorticoids. CONCLUSION Our results suggest a novel role for sFasL signalling in the TNF-α-induced RCD programme in neutrophils during COVID-19 and a potential therapeutic target to curb inflammation and thus influence disease severity and outcome.
Collapse
Affiliation(s)
- Tiziano A Schweizer
- Department of Infectious Diseases and Hospital EpidemiologyUniversity Hospital of ZurichUniversity of ZurichZurichSwitzerland
| | - Srikanth Mairpady Shambat
- Department of Infectious Diseases and Hospital EpidemiologyUniversity Hospital of ZurichUniversity of ZurichZurichSwitzerland
| | - Clement Vulin
- Department of Infectious Diseases and Hospital EpidemiologyUniversity Hospital of ZurichUniversity of ZurichZurichSwitzerland
| | - Sylvia Hoeller
- Department of Pathology and Molecular PathologyUniversity Hospital of ZurichUniversity of ZurichZurichSwitzerland
| | - Claudio Acevedo
- Department of Infectious Diseases and Hospital EpidemiologyUniversity Hospital of ZurichUniversity of ZurichZurichSwitzerland
| | - Markus Huemer
- Department of Infectious Diseases and Hospital EpidemiologyUniversity Hospital of ZurichUniversity of ZurichZurichSwitzerland
| | - Alejandro Gomez‐Mejia
- Department of Infectious Diseases and Hospital EpidemiologyUniversity Hospital of ZurichUniversity of ZurichZurichSwitzerland
| | - Chun‐Chi Chang
- Department of Infectious Diseases and Hospital EpidemiologyUniversity Hospital of ZurichUniversity of ZurichZurichSwitzerland
| | - Jeruscha Baum
- Department of Infectious Diseases and Hospital EpidemiologyUniversity Hospital of ZurichUniversity of ZurichZurichSwitzerland
| | - Sanne Hertegonne
- Department of Infectious Diseases and Hospital EpidemiologyUniversity Hospital of ZurichUniversity of ZurichZurichSwitzerland
| | - Eva Hitz
- Department of Infectious Diseases and Hospital EpidemiologyUniversity Hospital of ZurichUniversity of ZurichZurichSwitzerland
| | - Thomas C Scheier
- Department of Infectious Diseases and Hospital EpidemiologyUniversity Hospital of ZurichUniversity of ZurichZurichSwitzerland
| | - Daniel A Hofmaenner
- Institute for Intensive Care MedicineUniversity Hospital of ZurichUniversity of ZurichZurichSwitzerland
| | - Philipp K Buehler
- Institute for Intensive Care MedicineUniversity Hospital of ZurichUniversity of ZurichZurichSwitzerland
| | - Holger Moch
- Department of Pathology and Molecular PathologyUniversity Hospital of ZurichUniversity of ZurichZurichSwitzerland
| | - Reto A Schuepbach
- Institute for Intensive Care MedicineUniversity Hospital of ZurichUniversity of ZurichZurichSwitzerland
| | - Silvio D Brugger
- Department of Infectious Diseases and Hospital EpidemiologyUniversity Hospital of ZurichUniversity of ZurichZurichSwitzerland
| | - Annelies S Zinkernagel
- Department of Infectious Diseases and Hospital EpidemiologyUniversity Hospital of ZurichUniversity of ZurichZurichSwitzerland
| |
Collapse
|
12
|
Klein K, Schweizer TA, Siwy K, Lechmann B, Karol A, von Rechenberg B, Achermann Y, Darwiche SE. Establishment of a localized acute implant-associated Staphylococcus aureus bone infection model in sheep. Pathog Dis 2021; 79:6298225. [PMID: 34124751 DOI: 10.1093/femspd/ftab032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 06/11/2021] [Indexed: 11/15/2022] Open
Abstract
Orthopedic implant-associated bacterial infections with Staphylococcus aureus constitute a major clinical problem, and large pre-clinical animal models remain scarce. The aim of this study was to establish a standardized method of a localized, acute S. aureus bone infection in the presence of complex implanted devices in a sheep model. Four sheep underwent surgery receiving a complex implanted metallic device with a component stabilizing a bone defect created in the left tibial metaphysis, and an attached component placed in adjacent soft tissue. The bone defect was inoculated with S. aureus strain ATCC25293 (1 × 104 CFU). Twenty one days later, the surgery site was macroscopically evaluated, tissue samples and implants harvested for bacterial cell count quantification and tissue samples histologically analyzed. The animals exhibited clinical signs of localized infection (e.g. swelling, lameness, pain) but did not develop symptoms of sepsis. After euthanasia, macroscopic assessment revealed a localized bone and soft tissue infection at the surgery site. Histologically, an acute inflammation with neutrophils but also signs of bone destruction with necrosis was noted. An ovine model of a localized, acute S. aureus bone infection with complex implants was successfully established and could be used to test novel treatments against orthopedic implant-associated infections.
Collapse
Affiliation(s)
- Karina Klein
- Musculoskeletal Research Unit, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Tiziano A Schweizer
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Katharina Siwy
- Musculoskeletal Research Unit, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | | | - Agnieszka Karol
- Musculoskeletal Research Unit, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Brigitte von Rechenberg
- Musculoskeletal Research Unit, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.,Competence Center for Applied Biotechnology and Molecular Medicine (CABMM), University of Zurich, Zurich, Switzerland
| | - Yvonne Achermann
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.,Competence Center for Applied Biotechnology and Molecular Medicine (CABMM), University of Zurich, Zurich, Switzerland
| | - Salim E Darwiche
- Musculoskeletal Research Unit, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.,Competence Center for Applied Biotechnology and Molecular Medicine (CABMM), University of Zurich, Zurich, Switzerland
| |
Collapse
|
13
|
Churchill NW, Hutchison MG, Graham SJ, Schweizer TA. Long-term changes in the small-world organization of brain networks after concussion. Sci Rep 2021; 11:6862. [PMID: 33767293 PMCID: PMC7994718 DOI: 10.1038/s41598-021-85811-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Accepted: 03/04/2021] [Indexed: 11/09/2022] Open
Abstract
There is a growing body of literature using functional MRI to study the acute and long-term effects of concussion on functional brain networks. To date, studies have largely focused on changes in pairwise connectivity strength between brain regions. Less is known about how concussion affects whole-brain network topology, particularly the “small-world” organization which facilitates efficient communication at both local and global scales. The present study addressed this knowledge gap by measuring local and global efficiency of 26 concussed athletes at acute injury, return to play (RTP) and one year post-RTP, along with a cohort of 167 athletic controls. On average, concussed athletes showed no alterations in local efficiency but had elevated global efficiency at acute injury, which had resolved by RTP. Athletes with atypically long recovery, however, had reduced global efficiency at 1 year post-RTP, suggesting long-term functional abnormalities for this subgroup. Analyses of nodal efficiency further indicated that global network changes were driven by high-efficiency visual and sensorimotor regions and low-efficiency frontal and subcortical regions. This study provides evidence that concussion causes subtle acute and long-term changes in the small-world organization of the brain, with effects that are related to the clinical profile of recovery.
Collapse
Affiliation(s)
- N W Churchill
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada. .,Neuroscience Research Program, St. Michael's Hospital, Toronto, ON, Canada.
| | - M G Hutchison
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada.,Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON, Canada
| | - S J Graham
- Physical Sciences Platform, Sunnybrook Research Institute, Sunnybrook Health Science Center, Toronto, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - T A Schweizer
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada.,Neuroscience Research Program, St. Michael's Hospital, Toronto, ON, Canada.,Faculty of Medicine (Neurosurgery), University of Toronto, Toronto, ON, Canada.,The Institute of Biomaterials and Biomedical Engineering (IBBME), University of Toronto, Toronto, ON, Canada
| |
Collapse
|
14
|
Schweizer TA, Shambat SM, Haunreiter VD, Mestres CA, Weber A, Maisano F, Zinkernagel AS, Hasse B. Polyester Vascular Graft Material and Risk for Intracavitary Thoracic Vascular Graft Infection 1. Emerg Infect Dis 2020; 26:2448-2452. [PMID: 32946737 PMCID: PMC7510746 DOI: 10.3201/eid2610.191711] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Prosthetic vascular graft infections of the thoracic aorta are rare but can be fatal. Our comparison of collagen- and gelatin-coated grafts showed that collagen-coated grafts were associated with increased biofilm formation and bacterial adherence in vitro and with higher rates of perioperative vascular graft infections in vivo.
Collapse
|
15
|
Nur S, Sparber F, Lemberg C, Guiducci E, Schweizer TA, Zwicky P, Becher B, LeibundGut-Landmann S. IL-23 supports host defense against systemic Candida albicans infection by ensuring myeloid cell survival. PLoS Pathog 2019; 15:e1008115. [PMID: 31887131 PMCID: PMC6957211 DOI: 10.1371/journal.ppat.1008115] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 01/13/2020] [Accepted: 10/01/2019] [Indexed: 01/21/2023] Open
Abstract
The opportunistic fungal pathogen Candida albicans can cause invasive infections in susceptible hosts and the innate immune system, in particular myeloid cell-mediated immunity, is critical for rapid immune protection and host survival during systemic candidiasis. Using a mouse model of the human disease, we identified a novel role of IL-23 in antifungal defense. IL-23-deficient mice are highly susceptible to systemic infection with C. albicans. We found that this results from a drastic reduction in all subsets of myeloid cells in the infected kidney, which in turn leads to rapid fungal overgrowth and renal tissue injury. The loss in myeloid cells is not due to a defect in emergency myelopoiesis or the recruitment of newly generated cells to the site of infection but, rather, is a consequence of impaired survival of myeloid cells at the site of infection. In fact, the absence of a functional IL-23 pathway causes massive myeloid cell apoptosis upon C. albicans infection. Importantly, IL-23 protects myeloid cells from apoptosis independently of the IL-23-IL-17 immune axis and independently of lymphocytes and innate lymphoid cells. Instead, our results suggest that IL-23 acts in a partially autocrine but not cell-intrinsic manner within the myeloid compartment to promote host protection from systemic candidiasis. Collectively, our data highlight an unprecedented and non-canonical role of IL-23 in securing survival of myeloid cells, which is key for maintaining sufficient numbers of cells at the site of infection to ensure efficient host protection. Linked to advances in medical technology and the resulting increase in the number of intensive care patients, nosocomial infections with Candida albicans are on the rise. In patients suffering from invasive candidiasis the innate immune response is typically severely impaired. Strengthening the innate immune system has become a promising approach complementing the use of antifungal drugs. Our findings identify an unexpected and IL-17-independent role of IL-23 that prevents rapid death of myeloid cells during systemic candidiasis and thereby promotes optimal protection from disease. As such, IL-23 represents an important new piece in the puzzle of the finely tuned network of cytokines that regulates the innate immune response to fungal infection. Our results contribute to a better understanding of myeloid cell regulation during infection and thereby open new perspectives for future immunotherapeutic applications that may improve patient outcome.
Collapse
Affiliation(s)
- Selim Nur
- Section of Immunology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
| | - Florian Sparber
- Section of Immunology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
| | - Christina Lemberg
- Section of Immunology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
| | - Eva Guiducci
- Section of Immunology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
| | - Tiziano A. Schweizer
- Section of Immunology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
| | - Pascale Zwicky
- Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland
| | - Burkhard Becher
- Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland
| | | |
Collapse
|
16
|
Schweizer TA, Dixon MJ, Westwood D, Piskopos M. Contribution of visual and semantic proximity to identification performance in a viral encephalitis patient. Brain Cogn 2001; 46:260-4. [PMID: 11527344 DOI: 10.1016/s0278-2626(01)80079-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Identification deficits were investigated in F.S., a patient with herpes simplex viral encephalitis. F.S.'s confrontation naming abilities were assessed for multiple repetitions of 12 line drawings of artifacts. Six of the line drawings consisted of psychologically "close" objects (i.e., objects that share many visual and semantic features with other objects) and 6 were psychologically "disparate" objects (i.e., objects that share few, if any, visual and semantic features with other objects). F.S. correctly named all of the objects from the "disparate" category but only 47% of the objects from the "close" category. We also tested F.S. using novel, computer-generated shapes that were paired with artifact labels. We paired semantically close or disparate labels to shapes and F.S. attempted to learn these pairings. Overall, F.S.'s shape-label confusions were most detrimentally affected when we used labels that referred to objects that were visually close and semantically distinct. Results indicate that, at least for our patient, visual similarity contributed the most to his identification errors.
Collapse
Affiliation(s)
- T A Schweizer
- Department of Psychology, University of Waterloo, Ontario, Canada
| | | | | | | |
Collapse
|
17
|
Abstract
The production of transitive limb gestures is optimized when the appropriate tool can be physically manipulated. Little research has addressed the independent contributions of visual and nonvisual sources of sensory information to this phenomenon. In this study, 12 control, 37 LHD, and 50 RHD stroke patients performed transitive limb gestures to pantomime (to verbal command with the object visible) and object manipulation. Performance was more accurate in the object manipulation condition, suggesting that haptic and kinesthetic cues are important for transitive gesture production. Various patterns of performance were observed in the stroke groups, indicating that selective damage to the haptic/kinesthetic processing system is possible and common following unilateral stroke.
Collapse
Affiliation(s)
- D A Westwood
- Department of Psychology, Faculty of Medicine, University of Waterloo
| | | | | | | | | | | |
Collapse
|
18
|
Abstract
OBJECTIVE As shown in previous research, alcohol suppresses negative priming, an effect that normally occurs when subjects are required to respond to information that had been previously ignored. The present research examined the generality of this effect by testing the effect of alcohol on responses to positively primed stimuli that did not require responding to previously ignored information. METHOD Twenty-eight male social drinkers performed a color-naming reaction time task that measured both negative and positive priming effects. After a baseline test on the task, they received either 0.56 g/kg of alcohol or a placebo, and then performed the task twice. RESULTS The results showed a differential effect of alcohol on negative and positive priming. Alcohol suppressed negative priming, but had no effect on the magnitude of positive priming. CONCLUSIONS Evidence for a selective effect of alcohol on negative, but not positive, priming suggests that the drug does not reduce negative priming by impairing memory of priming stimulus information. Rather, the findings provide further support for a specific impairment of an inhibitory process that normally serves to prevent interference from distracting, to be ignored, stimuli. Impairment of this process by alcohol could represent a basic cognitive mechanism by which the drug disrupts performance of laboratory tasks that require visual attention, such as divided attention and vigilance tasks.
Collapse
Affiliation(s)
- M T Fillmore
- Department of Psychology, University of Kentucky, Lexington 40506-0044, USA.
| | | | | |
Collapse
|
19
|
Abstract
The present study was designed to examine the frequency and severity of apraxia in patients with left- or right-hemisphere stroke in both pantomime and imitation conditions and to compare the frequency of apraxia in each stroke group across the three patterns of apraxia described in Roy's model (Roy, 1996). Ninety-nine stroke patients and 15 age-matched healthy adults performed eight transitive gestures to pantomime and to imitation. Gestural performance was quantified as accuracy on five performance dimensions; a composite score, an arithmetic combination of the five performance dimensions, was used as an index of the overall accuracy. Analyses revealed a comparable proportion of patients in each stroke group were classified as apraxic in the imitation condition, but a higher proportion of left stroke patients were apraxic in the pantomime condition. The severity of apraxia in each stroke group and the performance dimensions affected were, however, comparable. Analyses of the patterns of apraxia (pantomime alone, imitation alone or apraxia in both conditions) revealed a higher frequency of apraxia in both stroke groups for the pattern reflecting apraxia in both conditions, indicating that a disruption at the movement execution stage of gesture performance was most common.
Collapse
Affiliation(s)
- E A Roy
- Department of Kinesiology, Waterloo, Ontario, Canada.
| | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Abstract
OBJECTIVE This research examined the effect of alcohol on negative priming, which is considered to reflect a basic process of selective attention. METHOD Male social drinkers (N = 28) performed a color naming reaction time (RT) task that measured negative priming. After a baseline test on the task, they received either 0.56 g/kg of alcohol or a placebo; they then performed the task twice. RESULTS In accord with the hypotheses, alcohol suppressed negative priming during the ascending limb but not during the descending limb of the blood alcohol curve. No suppression of negative priming was evident under placebo. CONCLUSIONS The suppression of this process by alcohol may represent a basic mechanism by which the drug reduces the ability to efficiently allocate attention and leads to impaired performance on various attention-based tasks (e.g., divided attention and vigilance tasks).
Collapse
Affiliation(s)
- M T Fillmore
- Department of Psychology, University of Kentucky, Lexington 40506-0044, USA
| | | | | |
Collapse
|
21
|
Dixon MJ, Koehler D, Schweizer TA, Guylee MJ. Superior single dimension relative to "exclusive or" categorization performance by a patient with category-specific visual agnosia: empirical data and an ALCOVE simulation. Brain Cogn 2000; 43:152-8. [PMID: 10857684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
ELM, a patient with category-specific visual agnosia, was tested on a single-dimension categorization problem, and the "exclusive or" (XOR) categorization problem. Stimuli were computer-generated shapes in which exemplars within a shape set shared values across two visual dimensions (curvature and thickness). In single-dimension categorization only curvature was relevant, and ELM performed as well as normal participants. In the XOR problem, categorization depended on being able to extract from memory values on curvature AND thickness for each exemplar, and ELM was significantly impaired on this task. A computer simulation using ALCOVE (Kruschke, 1992) reproduced ELM's behavior by changing a single (specificity) parameter related to how easily proximate objects within a multidimensional shape space could be disambiguated.
Collapse
|
22
|
Dixon MJ, Piskopos M, Schweizer TA. Musical instrument naming impairments: the crucial exception to the living/nonliving dichotomy in category-specific agnosia. Brain Cogn 2000; 43:158-64. [PMID: 10857685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
In category-specific agnosia (CSA) patients typically have more trouble naming animals, fruits, and vegetables than tools, furniture, and articles of clothing. A crucial exception to this living vs nonliving rule involves the category of musical instruments. Patients with problems naming living objects often repeatedly fail to name musical instruments. In CSA it is crucial to equate living and nonliving object lists on object name frequency, complexity, and familiarity. The present study shows, however, that even the most rigorously controlled object lists can lead to erroneous conclusions if nonliving stimuli contain an overrepresentation of musical instruments. Naming capabilities of a herpes encephalitis patient were assessed using matched lists of living and nonliving objects and showed no indication of category-specific deficits. When exemplars were separated into biological objects, musical instruments and man-made artifacts, strong category-specificity emerged: artifact naming was flawless whereas musical instrument and biological object naming were both severely impaired. It is concluded that CSA is a veridical phenomenon but that our understanding of CSA is limited by adhering to the spurious living/nonliving distinction.
Collapse
Affiliation(s)
- M J Dixon
- Department of Psychology, University of Waterloo
| | | | | |
Collapse
|