In vitro comparison of human fibroblasts from intact and ruptured ACL for use in tissue engineering

Institut de Biologie et Chimie des Protéines, Centre National de la Recherche Scientifique - Université Claude Bernard Lyon 1, Lyon, France.
European cells & materials (Impact Factor: 4.89). 02/2007; 14:78-90; discussion 90-1.
Source: PubMed

ABSTRACT The present study compares fibroblasts extracted from intact and ruptured human anterior cruciate ligaments (ACL) for creation of a tissue engineered ACL-construct, made of porcine small intestinal submucosal extracellular matrix (SIS-ECM) seeded with these ACL cells. The comparison is based on histological, immunohistochemical and RT-PCR analyses. Differences were observed between cells in a ruptured ACL (rACL) and cells in an intact ACL (iACL), particularly with regard to the expression of integrin subunits and smooth muscle actin (SMA). Despite these differences in the cell source, both cell populations behaved similarly when seeded on an SIS-ECM scaffold, with similar cell morphology, connective tissue organization and composition, SMA and integrin expression. This study shows the usefulness of naturally occurring scaffolds such as SIS-ECM for the study of cell behaviour in vitro, and illustrates the possibility to use autologous cells extracted from ruptured ACL biopsies as a source for tissue engineered ACL constructs.

    • "Another potential limitation is the isolation of cells from ACL tissue that was surgically removed following injury. However, while cells from injured or intact ACL can exhibit differences in phenotype, Brune and colleagues (Brune et al., 2007) have shown these two populations exhibit similar cell morphology, tissue organization, and expression of integrins, elastin, and smooth muscle actin. "
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    ABSTRACT: Exercise stimulates a dramatic change in the concentration of circulating hormones, such as growth hormone (GH), but the biological functions of this response are unclear. Pharmacological GH administration stimulates collagen synthesis; however, whether the post-exercise systemic milieu has a similar action is unknown. We aimed to determine whether the collagen content and tensile strength of tissue-engineered ligaments is enhanced by serum obtained post-exercise. Primary cells from a human anterior cruciate ligament (ACL) were used to engineer ligament constructs in vitro. Blood obtained from twelve healthy young men 15 min after resistance exercise contained GH concentrations that were ∼7-fold greater than resting serum (P < 0.001), whereas IGF-1 was not elevated at this time point (P = 0.21 vs rest). Ligament constructs were treated for 7 d with media supplemented with serum obtained at rest (RestTx) or 15 min post-exercise (ExTx), before tensile testing and collagen content analysis. Compared with RestEx, ExTx enhanced collagen content (+19%; 181 ± 33 vs. 215 ± 40 μg per construct P = 0.001) and ligament mechanical properties - maximal tensile load (+17%, P = 0.03 vs RestTx) and ultimate tensile strength (+10%, P = 0.15 vs RestTx). In a separate set of engineered ligaments, recombinant IGF-1, but not GH, enhanced collagen content and mechanics. Bioassays in 2D culture revealed that acute treatment with post-exercise serum activated mTORC1 and ERK1/2. In conclusion, the post-exercise biochemical milieu, but not recombinant GH, enhances collagen content and tensile strength of engineered ligaments, in association with mTORC1 and ERK1/2 activation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    The Journal of Physiology 08/2015; DOI:10.1113/JP270737 · 4.54 Impact Factor
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    • "ACLs contain a small subpopulation of fibroblasts positive for α-smooth muscle actin (α-SMA) [9], as well as cells that express certain markers of mesenchymal progenitor cells, including nucleostemin, SSEA-4, STRO-1, and Oct-4 [10-12]. "
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    ABSTRACT: Introduction Anterior cruciate ligament (ACL) degeneration is observed in most osteoarthritis (OA)-affected knee joints. However, the specific spatial and temporal relations of these changes and their association with extracellular matrix (ECM) degeneration are not well understood. The objective of this study was to characterize the patterns and relations of aging-related and OA-associated changes in ACL cells and the ECM. Methods Human knee joints from 80 donors (age 23 through 94) were obtained at autopsy. ACL degeneration was assessed histologically by using a quantitative scoring system. Tissue sections were analyzed for cell density, cell organization, ECM components, ECM-degrading enzymes and markers of differentiation, proliferation, and stem cells. Results Total cell number in normal ACL decreased with aging but increased in degenerated ACL, because of the formation of perivascular cell aggregates and islands of chondrocyte-like cells. Matrix metalloproteinase (MMP)-1, -3, and -13 expression was reduced in aging ACL but increased in degenerated ACL, mainly in the chondrocyte-like cells. Collagen I was expressed throughout normal and degenerated ACL. Collagen II and X were detected only in the areas with chondroid metaplasia, which also expressed collagen III. Sox9, Runt-related transcription factor 2 (Runx2), and scleraxis expression was increased in the chondrocyte-like cells in degenerated ACL. Alpha-smooth muscle actin (α-SMA), a marker of myofibroblasts and the progenitor cell marker STRO-1, decreased with aging in normal ACL. In degenerated ACL, the new cell aggregates were positive for α-SMA and STRO-1. Conclusions ACL aging is characterized by reduced cell density and activation. In contrast, ACL degeneration is associated with cell recruitment or proliferation, including progenitor cells or myofibroblasts. Abnormally differentiated chondrocyte-like cell aggregates in degenerated ACL produce abnormal ECM and may predispose to mechanical failure.
    Arthritis research & therapy 02/2013; 15(1):R29. DOI:10.1186/ar4165 · 3.75 Impact Factor
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    • "Another study compared the performance of fibroblasts extracted from both intact and ruptured human ACLs. They observed that cells extracted from the ruptured ACL were more useful in ligament tissue engineering [17]. Fibroblasts from other sources such as the skin are also being tested for their use in ligament tissue engineering. "
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    ABSTRACT: Tissue engineering is an emerging discipline that combines the principle of science and engineering. It offers an unlimited source of natural tissue substitutes and by using appropriate cells, biomimetic scaffolds, and advanced bioreactors, it is possible that tissue engineering could be implemented in the repair and regeneration of tissue such as bone, cartilage, tendon, and ligament. Whilst repair and regeneration of ligament tissue has been demonstrated in animal studies, further research is needed to improve the biomechanical properties of the engineered ligament if it is to play an important part in the future of human ligament reconstruction surgery. We evaluate the current literature on ligament tissue engineering and its role in anterior cruciate ligament reconstruction.
    01/2012; 2012:438125. DOI:10.1155/2012/438125
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