Basic Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Stem Cells. Mar 26, 2015; 7(2): 521-534
Published online Mar 26, 2015. doi: 10.4252/wjsc.v7.i2.521
Mesenchymal stem cells and collagen patches for anterior cruciate ligament repair
Benjamin Gantenbein, Neha Gadhari, Samantha CW Chan, Sandro Kohl, Sufian S Ahmad
Benjamin Gantenbein, Neha Gadhari, Samantha CW Chan, Sufian S Ahmad, Tissue and Organ Mechanobiology, Institute for Surgical Technology and Biomechanics, University of Bern, CH-3014 Bern, Switzerland
Samantha CW Chan, EMPA, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
Sandro Kohl, Sufian S Ahmad, Orthopedic Department, Insel University Hospital, CH-3010 Bern, Switzerland
Author contributions: Gantenbein B collected the data, designed the study, prepared the manuscript and provided funding; Gadhari N contributed microscopy data; Chan SCW contributed to study design; Kohl S contributed to the study design; Ahmad SS edited the manuscript and provided funding.
Supported by A grant of the Swiss Orthopaedics Society (SGOT) to Ahmad SS, No. S99083814080618560.
Ethics approval: The study protocol was approved by local Ethical authorities.
Conflict-of-interest: The authors declare no conflicts of interest.
Data sharing: Technical appendix, statistical code, and dataset are available from the corresponding author (Benjamin.Gantenbein@istb.unibe.ch).
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Dr. Benjamin Gantenbein, Professor, Tissue and Organ Mechanobiology, Institute for Surgical Technology and Biomechanics, University of Bern, Stauffacherstrasse 78, CH-3014 Bern, Switzerland. benjamin.gantenbein@istb.unibe.ch
Telephone: +41-31-6315951 Fax: +41-31-6315960
Received: August 21, 2014
Peer-review started: August 22, 2014
First decision: September 4, 2014
Revised: October 30, 2014
Accepted: November 27, 2014
Article in press: December 1, 2014
Published online: March 26, 2015
Abstract

AIM: To investigate collagen patches seeded with mesenchymal stem cells (MSCs) and/or tenocytes (TCs) with regards to their suitability for anterior cruciate ligament (ACL) repair.

METHODS: Dynamic intraligamentary stabilization utilizes a dynamic screw system to keep ACL remnants in place and promote biological healing, supplemented by collagen patches. How these scaffolds interact with cells and what type of benefit they provide has not yet been investigated in detail. Primary ACL-derived TCs and human bone marrow derived MSCs were seeded onto two different types of 3D collagen scaffolds, Chondro-Gide® (CG) and Novocart® (NC). Cells were seeded onto the scaffolds and cultured for 7 d either as a pure populations or as “premix” containing a 1:1 ratio of TCs to MSCs. Additionally, as controls, cells were seeded in monolayers and in co-cultures on both sides of porous high-density membrane inserts (0.4 μm). We analyzed the patches by real time polymerase chain reaction, glycosaminoglycan (GAG), DNA and hydroxy-proline (HYP) content. To determine cell spreading and adherence in the scaffolds microscopic imaging techniques, i.e., confocal laser scanning microscopy (cLSM) and scanning electron microscopy (SEM), were applied.

RESULTS: CLSM and SEM imaging analysis confirmed cell adherence onto scaffolds. The metabolic cell activity revealed that patches promote adherence and proliferation of cells. The most dramatic increase in absolute metabolic cell activity was measured for CG samples seeded with tenocytes or a 1:1 cell premix. Analysis of DNA content and cLSM imaging also indicated MSCs were not proliferating as nicely as tenocytes on CG. The HYP to GAG ratio significantly changed for the premix group, resulting from a slightly lower GAG content, demonstrating that the cells are modifying the underlying matrix. Real-time quantitative polymerase chain reaction data indicated that MSCs showed a trend of differentiation towards a more tenogenic-like phenotype after 7 d.

CONCLUSION: CG and NC are both cyto-compatible with primary MSCs and TCs; TCs seemed to perform better on these collagen patches than MSCs.

Keywords: Anterior cruciate ligament rupture, Anterior cruciate ligament tenocyte, Dynamic intraligamentary stabilization system, Resazurin red assay, Mesenchymal stem cells, Real-time polymerase chain reaction, Histology, Scanning electron microscopy microscopy, Scanning electron microscopy

Core tip: Commercially available porcine or bovine-derived collagen type I and type III patches are cytocompatible for anterior cruciate ligament derived tenocytes (ACL-TCs) and for bone-marrow derived mesenchymal stem cells (MSCs). The combination of commercially available collagen patches with MSCs and ACL-TCs seems to be suitable for application with a dynamic intraligamentary stabilization system, which represents a novel technique to fix a ruptured ACL. However, co-culture of MSCs with ACL-TCs did show signs of differentiation of MSCs towards a more TC-like phenotype after a short-term culture of 7 d.