In vivo tissue integration and healing stiffness of woven collagen meshes: comparison to porcine dermis and polypropylene.
-
1
Case Western Reserve University, Biomedical Engineering, United States
-
2
University Hospitals, Department of Urology, United States
-
3
Case Western Reserve University, Department of Pathology, United States
-
4
University Hospitals, Department of General Surgery, United States
-
5
Case Western Reserve University, Mechanical and Aerospace Engineering, United States
Introduction: Shortcomings of modern sling materials used to manage stress urinary incontinence (SUI) underscore the need for an absorbable material that bio-integrates and matches stiffness of surrounding tissues[1]. Our group has developed an electrocompaction method for creating pure macroporous woven collagen meshes that are mechanically robust and induce de novo collagen production in vitro[2]. The aim of this study was to compare the tissue integration and remodeled stiffness of woven collagen meshes versus typical sling materials in an in vivo model to evaluate their potential application as a sling material.
Methods: Electrochemically aligned collagen (ELAC) threads were made as previously described, cross-linked using genipin (Wako) or a combination of 1-ethyl-3-(3-dimethylaminopropyl carboiimide) and N-hydroxy succinimide (EDC-NHS, Sigma) and woven into scaffolds (Fig. 1)[2],[3]. Decellularized porcine dermis (Xenmatrix™, Davol) and monofilament polypropylene mesh (Prolene™, Ethicon) were included as typical sling materials for comparison. Scaffolds for mechanical testing and tissue integration were implanted subcutaneously (dorsal and ventral respectively) in female Sprague Dawley rats. Mechanical testing samples were tested in tension until failure (10 mm/min) at baseline, 2 months, and 5 months along with native vaginal tissue and rectus fascia to act as reference points. Tissue integration samples were processed at 2 weeks, 2 months, and 5 months, then scored for granulation tissue, foreign body response, and fibrous encapsulation (Table 1). The Kruskal-Walis test for group wise comparisons and the Mann-Whitney test for pair-wise comparisons were employed for statistical analysis (α = 0.05).
Results and Discussion: Tissue integration and fibrous encapsulation were robust in Prolene, although there was no significant change in stiffness over time (Fig. 2). Modulus values for Xenmatrix were significantly greater than native tissue at baseline and at 2 months (p= 0.004, p= 0.004), but the stiffness fell about 10-fold at 5 months. Xenmatrix incited fibrous encapsulation, however, tissue integration was poor. EDC-NHS scaffolds also fell in stiffness from baseline, such they could not be recovered for testing at 5 months. The outcome is likely driven by poor fibrous encapsulation, leading to early resorption. Genipin scaffolds showed excellent tissue integration and fibrous encapsulation. Such host response is reflected in the increase in stiffness between 2 and 5 months; remodeled tissue halted the decline in material properties.
Conclusion: The woven framework of collagen meshes provided ample porosity for rapid and thorough cellularization in vivo, an advantage over porcine dermis. The longer term presence of collagen meshes was defined by crosslinking formulations, such that genipin cross-linked scaffolds maintained the overall stiffness beyond 2 months. Thus, genipin crosslinked collagen meshes hold potential as a new biomaterial to treat SUI.
References:
[1] Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR). “Preliminary Opinion: The safety of surgical meshes used in urogynecological surgery.” June 2015.
[2] Younesi M, Islam A, Kishore V, Anderson JM, Akkus, O. Tenogenic Induction of Human MSCs by Anisotropically Aligned Collagen Biotextiles. Adv. Func. Mater. 2014; 24: 5762-5770.
[3] Chunrong Yang. Enhanced physiochemical properties of collagen by using EDC-NHS cross-linking. Mater. Sci. 2012; 5: 913-918.
[4] ISO 10993-6:2007. Biological Evaluation of medical devices – Part 6: Test for local effects after implantation.
Keywords:
Scaffold,
Biocompatibility,
mechanical property,
in vivo tissue engineering
Conference:
10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016.
Presentation Type:
General Session Oral
Topic:
Biomaterials evaluation in animal models
Citation:
Chapin
KJ,
Khalifa
A,
Anderson
JM,
Novitsky
Y,
Hijaz
A and
Akkus
O
(2016). In vivo tissue integration and healing stiffness of woven collagen meshes: comparison to porcine dermis and polypropylene..
Front. Bioeng. Biotechnol.
Conference Abstract:
10th World Biomaterials Congress.
doi: 10.3389/conf.FBIOE.2016.01.00019
Copyright:
The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers.
They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.
The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.
Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.
For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.
Received:
27 Mar 2016;
Published Online:
30 Mar 2016.