1
|
Delaney LJ, MacDonald D, Leung J, Fitzgerald K, Sevit AM, Eisenbrey JR, Patel N, Forsberg F, Kepler CK, Fang T, Kurtz SM, Hickok NJ. Ultrasound-triggered antibiotic release from PEEK clips to prevent spinal fusion infection: Initial evaluations. Acta Biomater 2019; 93:12-24. [PMID: 30826477 PMCID: PMC6764442 DOI: 10.1016/j.actbio.2019.02.041] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 02/21/2019] [Accepted: 02/26/2019] [Indexed: 01/01/2023]
Abstract
Despite aggressive peri-operative antibiotic treatments, up to 10% of patients undergoing instrumented spinal surgery develop an infection. Like most implant-associated infections, spinal infections persist through colonization and biofilm formation on spinal instrumentation, which can include metal screws and rods for fixation and an intervertebral cage commonly comprised of polyether ether ketone (PEEK). We have designed a PEEK antibiotic reservoir that would clip to the metal fixation rod and that would achieve slow antibiotic release over several days, followed by a bolus release of antibiotics triggered by ultrasound (US) rupture of a reservoir membrane. We have found using human physiological fluid (synovial fluid), that higher levels (100–500 μg) of vancomycin are required to achieve a marked reduction in adherent bacteria vs. that seen in the common bacterial medium, trypticase soy broth. To achieve these levels of release, we applied a polylactic acid coating to a porous PEEK puck, which exhibited both slow and US-triggered release. This design was further refined to a one-hole or two-hole cylindrical PEEK reservoir that can clip onto a spinal rod for clinical use. Short-term release of high levels of antibiotic (340 ± 168 μg), followed by US-triggered release was measured (7420 ± 2992 μg at 48 h). These levels are sufficient to prevent adhesion of Staphylococcus aureus to implant materials. This study demonstrates the feasibility of an US-mediated antibiotic delivery device, which could be a potent weapon against spinal surgical site infection.
Collapse
Affiliation(s)
- Lauren J Delaney
- Department of Radiology, Thomas Jefferson University, 132 S. 10th Street, Philadelphia, PA 19107, USA
| | - Daniel MacDonald
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA
| | - Jay Leung
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA
| | - Keith Fitzgerald
- Department of Orthopaedic Surgery, Thomas Jefferson University, 1015 Walnut Street, Philadelphia, PA 19107, USA
| | - Alex M Sevit
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA
| | - John R Eisenbrey
- Department of Radiology, Thomas Jefferson University, 132 S. 10th Street, Philadelphia, PA 19107, USA
| | - Neil Patel
- Department of Orthopaedic Surgery, Thomas Jefferson University, 1015 Walnut Street, Philadelphia, PA 19107, USA
| | - Flemming Forsberg
- Department of Radiology, Thomas Jefferson University, 132 S. 10th Street, Philadelphia, PA 19107, USA
| | - Christopher K Kepler
- Department of Orthopaedic Surgery, Thomas Jefferson University, 1015 Walnut Street, Philadelphia, PA 19107, USA; The Rothman Institute, Thomas Jefferson University, 925 Chestnut Street, Philadelphia, PA 19107, USA
| | - Taolin Fang
- Department of Orthopaedic Surgery, Thomas Jefferson University, 1015 Walnut Street, Philadelphia, PA 19107, USA; The Rothman Institute, Thomas Jefferson University, 925 Chestnut Street, Philadelphia, PA 19107, USA
| | - Steven M Kurtz
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA; Exponent, Inc., 3440 Market Street Suite 600, Philadelphia, PA 19104, USA
| | - Noreen J Hickok
- Department of Orthopaedic Surgery, Thomas Jefferson University, 1015 Walnut Street, Philadelphia, PA 19107, USA.
| |
Collapse
|
3
|
Epstein RJ. The unpluggable in pursuit of the undruggable: tackling the dark matter of the cancer therapeutics universe. Front Oncol 2013; 3:304. [PMID: 24377088 PMCID: PMC3859984 DOI: 10.3389/fonc.2013.00304] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 11/29/2013] [Indexed: 01/19/2023] Open
Abstract
The notion that targeted drugs can unplug gain-of-function tumor pathways has revitalized pharmaceutical research, but the survival benefits of this strategy have so far proven modest. A weakness of oncogene-blocking approaches is that they do not address the problem of cancer progression as selected by the recessive phenotypes of genetic instability and apoptotic resistance which in turn arise from loss-of-function – i.e., undruggable – defects of caretaker (e.g., BRCA, MLH1) or gatekeeper (e.g., TP53, PTEN) suppressor genes. Genetic instability ensures that rapid cell kill is balanced by rapid selection for apoptotic resistance and hence for metastasis, casting doubt on the assumption that cytotoxicity (“response”) remains the best way to identify survival-enhancing drugs. In the absence of gene therapy, it is proposed here that caretaker-defective (high-instability) tumors may be best treated with low-lethality drugs inducing replicative (RAS-RAF-ERK) arrest or dormancy, causing “stable disease” rather than tumorilytic remission. Gatekeeper-defective (death-resistant) tumors, on the other hand, may be best managed by combining survival (PI3K-AKT-mTOR) pathway blockade with metronomic or sequential pro-apoptotic drugs.
Collapse
Affiliation(s)
- Richard J Epstein
- Laboratory of Genome Evolution & Informatics, The Kinghorn Cancer Centre, and Clinical Informatics & Research Centre, Department of Oncology, St Vincent's Hospital, UNSW Clinical School , Sydney, NSW , Australia
| |
Collapse
|
4
|
Döppler H, Bastea LI, Eiseler T, Storz P. Neuregulin mediates F-actin-driven cell migration through inhibition of protein kinase D1 via Rac1 protein. J Biol Chem 2012; 288:455-65. [PMID: 23148218 DOI: 10.1074/jbc.m112.397448] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neuregulin (NRG; heregulin) is overexpressed in ∼30% of breast cancers and mediates various processes involved in tumor progression, including tumor cell migration and invasion. Here, we show that NRG mediates its effects on tumor cell migration via PKD1. Downstream of RhoA, PKD1 can prevent directed cell migration through phosphorylation of its substrate SSH1L. NRG exerts its inhibitory effects on PKD1 through Rac1/NADPH oxidase, leading to decreased PKD1 activation loop phosphorylation and decreased activity toward SSH1L. The consequence of PKD1 inhibition by NRG is decreased binding of 14-3-3 to SSH1L, localization of SSH1L to F-actin at the leading edge, and increased cofilin activity, resulting in increased reorganization of the actin cytoskeleton and cell motility. Our data provide a mechanism through which the Rho GTPase Rac1 cross-talks with PKD1 signaling pathways to facilitate directed cell migration.
Collapse
Affiliation(s)
- Heike Döppler
- Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Mayo Clinic, Jacksonville, Florida 32224, USA
| | | | | | | |
Collapse
|