Marc van Vijven1,2, Bart van Groningen3, Joyce N Kimenai4, Maria C van der Steen3,5, Marina van Doeselaar4, Rob P A Janssen4,3,6, Keita Ito4,7, Jasper Foolen4,7. 1. Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Building 15, Groene Loper, Gemini-Zuid 4.12, PO Box 513, 5600MB, Eindhoven, The Netherlands. m.v.vijven@tue.nl. 2. Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, the Netherlands. m.v.vijven@tue.nl. 3. Department of Orthopaedic Surgery, Máxima MC, Eindhoven, the Netherlands. 4. Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Building 15, Groene Loper, Gemini-Zuid 4.12, PO Box 513, 5600MB, Eindhoven, The Netherlands. 5. Department of Orthopaedic Surgery, Catharina Hospital Eindhoven, Eindhoven, the Netherlands. 6. Fontys University of Applied Sciences, Eindhoven, the Netherlands. 7. Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, the Netherlands.
Abstract
PURPOSE: Upon anterior cruciate ligament (ACL) rupture, reconstruction is often required, with the hamstring tendon autograft as most widely used treatment. Post-operative autograft remodeling enhances graft rupture risk, which occurs in up to 10% of the patient population, increasing up to 30% of patients aged under 20 years. Therefore, this research aimed to identify potential biological predictors for graft rupture, derived from patient-specific tissue remodeling-related cell properties in an in vitro micro-tissue platform. METHODS: Hamstring tendon-derived cells were obtained from remnant autograft tissue after ACL reconstructions (36 patients, aged 12-55 years), and seeded in collagen I gels on a micro-tissue platform. Micro-tissue compaction over time - induced by altering the boundary constraints - was monitored. Pro-collagen I expression was assessed using ELISA, and protein expression of tenomodulin and α-smooth muscle actin were measured using Western blot. Expression and activity of matrix metalloproteinase 2 were determined using gelatin zymography. RESULTS: Only micro-tissues corresponding to younger patients occasionally released themselves from the constraining posts. Pro-collagen I expression was significantly higher in younger patients. Differences in α-smooth muscle actin and tenomodulin expression between patients were found, but these were age-independent. Active matrix metalloproteinase 2 expression was slightly more abundant in younger patients. CONCLUSIONS: The presented micro-tissue platform exposed patient-specific remodeling-related differences between tendon-derived cells, with the micro-tissues that released from constraining posts and pro-collagen I expression best reflecting the clinical age-dependency of graft rupture. These properties can be the starting point in the quest for potential predictors for identifying individual patients at risk for graft rupture.
PURPOSE: Upon anterior cruciate ligament (ACL) rupture, reconstruction is often required, with the hamstring tendon autograft as most widely used treatment. Post-operative autograft remodeling enhances graft rupture risk, which occurs in up to 10% of the patient population, increasing up to 30% of patients aged under 20 years. Therefore, this research aimed to identify potential biological predictors for graft rupture, derived from patient-specific tissue remodeling-related cell properties in an in vitro micro-tissue platform. METHODS: Hamstring tendon-derived cells were obtained from remnant autograft tissue after ACL reconstructions (36 patients, aged 12-55 years), and seeded in collagen I gels on a micro-tissue platform. Micro-tissue compaction over time - induced by altering the boundary constraints - was monitored. Pro-collagen I expression was assessed using ELISA, and protein expression of tenomodulin and α-smooth muscle actin were measured using Western blot. Expression and activity of matrix metalloproteinase 2 were determined using gelatin zymography. RESULTS: Only micro-tissues corresponding to younger patients occasionally released themselves from the constraining posts. Pro-collagen I expression was significantly higher in younger patients. Differences in α-smooth muscle actin and tenomodulin expression between patients were found, but these were age-independent. Active matrix metalloproteinase 2 expression was slightly more abundant in younger patients. CONCLUSIONS: The presented micro-tissue platform exposed patient-specific remodeling-related differences between tendon-derived cells, with the micro-tissues that released from constraining posts and pro-collagen I expression best reflecting the clinical age-dependency of graft rupture. These properties can be the starting point in the quest for potential predictors for identifying individual patients at risk for graft rupture.
Authors: Isabel N Tromp; Jasper Foolen; Marina van Doeselaar; Ying Zhang; Danny Chan; Moyo C Kruyt; Laura B Creemers; Rene M Castelein; Keita Ito Journal: J Orthop Res Date: 2020-12-01 Impact factor: 3.102