1
|
Oakes RS, Polei MD, Skousen JL, Tresco PA. An astrocyte derived extracellular matrix coating reduces astrogliosis surrounding chronically implanted microelectrode arrays in rat cortex. Biomaterials 2017; 154:1-11. [PMID: 29117574 DOI: 10.1016/j.biomaterials.2017.10.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [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: 08/04/2017] [Revised: 09/25/2017] [Accepted: 10/02/2017] [Indexed: 12/27/2022]
Abstract
Available evidence suggests that the magnitude of the foreign body response (FBR) to implants placed in cortical brain tissue is affected by the extent of vasculature damage following device insertion and the magnitude of the ensuing macrophage response. Since the extracellular matrix (ECM) serves as a natural hemostatic and immunomodulatory agent, we examined the ability of an FDA-approved neurosurgical hemostatic coating and an ECM coating derived from primary rat astrocytes to reduce the FBR surrounding a penetrating microelectrode array chronically implanted in rat cortex. Using quantitative methods, we examined various components of the FBR in vitro and after implantation. In vitro assays showed that both coatings accelerated coagulation in a similar fashion but only the astrocyte-derived material suppressed macrophage activation. In addition, the ECM coating derived from astrocytes, also decreased the astrogliotic response 8 weeks after implantation. Neither coating had a significant influence on the intensity or spatial distribution of FBR biomarkers 1 week after implantation or on degree of macrophage activation or neuronal survival at the later time point. The results show that microelectrode coatings with similar hemostatic properties but different immunomodulatory characteristics differentially affect the FBR to an anchored, single-shank, silicon microelectrode array. The results also support the concept that divergent biological pathways affect the various components of the FBR in the CNS and suggests that decreasing its impact will require a multifaceted approach.
Collapse
Affiliation(s)
- Robert S Oakes
- Department of Bioengineering, University of Utah, 36 S Wasatch Dr, 151 SMBB, Room 4511, Salt Lake City, UT, 84112, USA
| | - Michael D Polei
- Department of Bioengineering, University of Utah, 36 S Wasatch Dr, 151 SMBB, Room 4511, Salt Lake City, UT, 84112, USA
| | - John L Skousen
- Department of Bioengineering, University of Utah, 36 S Wasatch Dr, 151 SMBB, Room 4511, Salt Lake City, UT, 84112, USA
| | - Patrick A Tresco
- Department of Bioengineering, University of Utah, 36 S Wasatch Dr, 151 SMBB, Room 4511, Salt Lake City, UT, 84112, USA.
| |
Collapse
|
2
|
Avula M, Jones D, Rao AN, McClain D, McGill LD, Grainger DW, Solzbacher F. Local release of masitinib alters in vivo implantable continuous glucose sensor performance. Biosens Bioelectron 2015; 77:149-56. [PMID: 26402593 DOI: 10.1016/j.bios.2015.08.059] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [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: 07/18/2015] [Revised: 08/24/2015] [Accepted: 08/25/2015] [Indexed: 11/25/2022]
Abstract
Continuous glucose monitoring (CGM) sensors are often advocated as a clinical solution to improve long-term glycemic control in the context of diabetes. Subcutaneous sensor inflammatory response, fouling and fibrous encapsulation resulting from the host foreign body response (FBR) reduce sensor sensitivity to glucose, eventually resulting in sensor performance compromise and device failure. Several combination device strategies load CGM sensors with drug payloads that release locally to tissue sites to mitigate FBR-mediated sensor failure. In this study, the mast cell-targeting tyrosine kinase inhibitor, masitinib, was released from degradable polymer microspheres delivered from the surfaces of FDA-approved human commercial CGM needle-type implanted sensors in a rodent subcutaneous test bed. By targeting the mast cell c-Kit receptor and inhibiting mast cell activation and degranulation, local masitinib penetration around the CGM to several hundred microns sought to reduce sensor fibrosis to extend CGM functional lifetimes in subcutaneous sites. Drug-releasing and control CGM implants were compared in murine percutaneous implant sites for 21 days using direct-wire continuous glucose reporting. Drug-releasing implants exhibited no significant difference in CGM fibrosis at implant sites but showed relatively stable continuous sensor responses over the study period compared to blank microsphere control CGM implants.
Collapse
Affiliation(s)
- M Avula
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, USA
| | - D Jones
- Department of Internal Medicine, University of Utah, Salt Lake City, UT 84112, USA
| | - A N Rao
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - D McClain
- Department of Internal Medicine, University of Utah, Salt Lake City, UT 84112, USA
| | - L D McGill
- Associated Regional and University Pathologist Laboratories, University of Utah, Salt Lake City, UT 84112, USA
| | - D W Grainger
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, USA; Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT 84112, USA.
| | - F Solzbacher
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, USA; Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84112, USA
| |
Collapse
|