International Journal of Molecular Sciences

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Editorial of Special Issue: Biological Basis of Musculoskeletal Regeneration 2019

by Franka Klatte-Schulz and Britt Wildemann

Int. J. Mol. Sci. 2020, 21(17), 5968; https://doi.org/10.3390/ijms21175968 - 19 Aug 2020

Viewed by 1490

Abstract

The Special Issue “Biological Basis of Musculoskeletal Regeneration 2019” aimed to collect research and review articles that cover various aspects of the molecular and cellular mechanisms of bone, cartilage, tendon/ligament, and muscle regeneration [...] Full article

(This article belongs to the Special Issue Biological Basis of Musculoskeletal Regeneration 2019)

Research

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18 pages, 3763 KiB

Open AccessArticle

Vertebral Bone Marrow-Derived Mesenchymal Stromal Cells from Osteoporotic and Healthy Patients Possess Similar Differentiation Properties In Vitro

by El-Mustapha Haddouti, Thomas M. Randau, Cäcilia Hilgers, Werner Masson, Robert Pflugmacher, Christof Burger, Sascha Gravius and Frank A. Schildberg

Int. J. Mol. Sci. 2020, 21(21), 8309; https://doi.org/10.3390/ijms21218309 - 5 Nov 2020

Cited by 7 | Viewed by 2711

Abstract

Osteoporosis is a disease characterized by low bone mass and an increased risk of fractures. Although several cellular players leading to osteoporosis have been identified, the role of mesenchymal stromal cells (MSC) is still not fully elaborated. The aim of this study was, [...] Read more.

Osteoporosis is a disease characterized by low bone mass and an increased risk of fractures. Although several cellular players leading to osteoporosis have been identified, the role of mesenchymal stromal cells (MSC) is still not fully elaborated. The aim of this study was, therefore, to isolate and characterize MSCs from vertebral body of healthy non-osteoporotic and osteoporotic patients, with a particular focus on their osteogenic differentiation potential. Isolated MSCs were characterized by their osteogenic, adipogenic, and chondrogenic differentiation, as well as surface marker expression, proliferation behavior, and immunomodulatory capacity. The mineralization process was confirmed using Alizarin Red S and alkaline phosphatase (ALP) stains and further evaluated by determining ALP activity, mineral deposition, and free phosphate ion release. MSCs from both healthy and osteoporotic patients showed common fibroblast-like morphology and similar proliferation behavior. They expressed the typical MSC surface markers and possessed immunomodulatory capacity. Both groups demonstrated solid trilineage differentiation potential; osteogenic differentiation was further confirmed by increased ALP activity, deposition of inorganic crystals, phosphate ion release, and expression of osteoblast marker genes. Overall, MSCs from osteoporotic and non-osteoporotic patients showed neither a difference in general MSC features nor in the detailed analysis regarding osteogenic differentiation. These data suggest that vertebral body MSCs from osteoporotic patients were not impaired; rather, they possessed full osteogenic potential compared to MSCs from non-osteoporotic patients. Full article

(This article belongs to the Special Issue Biological Basis of Musculoskeletal Regeneration 2019)

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12 pages, 2687 KiB

Open AccessArticle

Molecular and Functional Phenotypes of Human Bone Marrow-Derived Mesenchymal Stromal Cells Depend on Harvesting Techniques

by Sebastian G. Walter, Thomas M. Randau, Cäcilia Hilgers, El-Mustapha Haddouti, Werner Masson, Sascha Gravius, Christof Burger, Dieter C. Wirtz and Frank A. Schildberg

Int. J. Mol. Sci. 2020, 21(12), 4382; https://doi.org/10.3390/ijms21124382 - 19 Jun 2020

Cited by 25 | Viewed by 2859

Abstract

Mesenchymal stromal cells (MSC) harvested in different tissues from the same donor exhibit different phenotypes. Each phenotype is not only characterized by a certain pattern of cell surface markers, but also different cellular functionalities. Only recently were different harvesting and processing techniques found [...] Read more.

Mesenchymal stromal cells (MSC) harvested in different tissues from the same donor exhibit different phenotypes. Each phenotype is not only characterized by a certain pattern of cell surface markers, but also different cellular functionalities. Only recently were different harvesting and processing techniques found to contribute to this phenomenon as well. This study was therefore set up to investigate proteomic and functional properties of human bone marrow-derived MSCs (hBM-MSC). These were taken from the same tissue and donor site but harvested either as aspirate or bone chip cultures. Both MSC populations were profiled for MSC markers defined by the International Society for Cellular Therapy (ISCT), MSC markers currently under discussion and markers of particular interest. While classic ISCT MSC markers did not show any significant difference between aspirate and outgrowth hBM-MSCs, our additional characterization panel revealed distinct patterns of differentially expressed markers. Furthermore, hBM-MSCs from aspirate cultures demonstrated a significantly higher osteogenic differentiation potential than outgrowth MSCs, which could be confirmed using a transcriptional approach. Our comparison of MSC phenotypes obtained by different harvesting techniques suggests the need of future standardized harvesting, processing and phenotyping procedures in order to gain better comparability in the MSC field. Full article

(This article belongs to the Special Issue Biological Basis of Musculoskeletal Regeneration 2019)

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21 pages, 4478 KiB

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Detecting the Effects of the Glucocorticoid Dexamethasone on Primary Human Skeletal Muscle Cells—Differences to the Murine Cell Line

by Eva K. Langendorf, Pol M. Rommens, Philipp Drees, Stefan G. Mattyasovszky and Ulrike Ritz

Int. J. Mol. Sci. 2020, 21(7), 2497; https://doi.org/10.3390/ijms21072497 - 3 Apr 2020

Cited by 12 | Viewed by 5978

Abstract

Skeletal muscle atrophy is characterized by a decrease in muscle fiber size as a result of a decreased protein synthesis, which leads to degradation of contractile muscle fibers. It can occur after denervation and immobilization, and glucocorticoids (GCs) may also increase protein breakdown [...] Read more.

Skeletal muscle atrophy is characterized by a decrease in muscle fiber size as a result of a decreased protein synthesis, which leads to degradation of contractile muscle fibers. It can occur after denervation and immobilization, and glucocorticoids (GCs) may also increase protein breakdown contributing to the loss of muscle mass and myofibrillar proteins. GCs are already used in vitro to induce atrophic conditions, but until now no studies with primary human skeletal muscle existed. Therefore, this study deals with the effects of the GC dexamethasone (dex) on primary human myoblasts and myotubes. After incubation with 1, 10, and 100 µM dex for 48 and 72 h, gene and protein expression analyses were performed by qPCR and Western blot. Foxo, MuRF-1, and MAFbx were significantly upregulated by dex, and there was increased gene expression of myogenic markers. However, prolonged incubation periods demonstrated no Myosin protein degradation, but an increase of MuRF-1 expression. In conclusion, applying dex did not only differently affect primary human myoblasts and myotubes, as differences were also observed when compared to murine cells. Based on our findings, studies using cell lines or animal cells should be interpreted with caution as signaling transduction and functional behavior might differ in diverse species. Full article

(This article belongs to the Special Issue Biological Basis of Musculoskeletal Regeneration 2019)

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19 pages, 3736 KiB

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Characterization and Comparison of Human and Ovine Mesenchymal Stromal Cells from Three Corresponding Sources

by El-Mustapha Haddouti, Thomas M. Randau, Cäcilia Hilgers, Werner Masson, Klaus J. Walgenbach, Robert Pflugmacher, Christof Burger, Sascha Gravius and Frank A. Schildberg

Int. J. Mol. Sci. 2020, 21(7), 2310; https://doi.org/10.3390/ijms21072310 - 27 Mar 2020

Cited by 16 | Viewed by 3054

Abstract

Currently, there is an increasing focus on mesenchymal stromal cells (MSC) as therapeutic option in bone pathologies as well as in general regenerative medicine. Although human MSCs have been extensively characterized and standardized, ovine MSCs are poorly understood. This limitation hampers clinical progress, [...] Read more.

Currently, there is an increasing focus on mesenchymal stromal cells (MSC) as therapeutic option in bone pathologies as well as in general regenerative medicine. Although human MSCs have been extensively characterized and standardized, ovine MSCs are poorly understood. This limitation hampers clinical progress, as sheep are an excellent large animal model for orthopedic studies. Our report describes a direct comparison of human and ovine MSCs from three corresponding sources under the same conditions. All MSCs presented solid growth behavior and potent immunomodulatory capacities. Additionally, we were able to identify common positive (CD29, CD44, CD73, CD90, CD105, CD166) and negative (CD14, CD34, CD45, HLA-DR) surface markers. Although both human and ovine MSCs showed strong osteogenic potential, direct comparison revealed a slower mineralization process in ovine MSCs. Regarding gene expression level, both human and ovine MSCs presented a comparable up-regulation of Runx2 and a trend toward down-regulation of Col1A during osteogenic differentiation. In summary, this side by side comparison defined phenotypic similarities and differences of human and ovine MSCs from three different sources, thereby contributing to a better characterization and standardization of ovine MSCs. The key findings shown in this report demonstrate the utility of ovine MSCs in preclinical studies for MSC-based therapies. Full article

(This article belongs to the Special Issue Biological Basis of Musculoskeletal Regeneration 2019)

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17 pages, 4962 KiB

Open AccessArticle

Biofabrication of SDF-1 Functionalized 3D-Printed Cell-Free Scaffolds for Bone Tissue Regeneration

by Alina Lauer, Philipp Wolf, Dorothea Mehler, Hermann Götz, Mehmet Rüzgar, Andreas Baranowski, Dirk Henrich, Pol Maria Rommens and Ulrike Ritz

Int. J. Mol. Sci. 2020, 21(6), 2175; https://doi.org/10.3390/ijms21062175 - 21 Mar 2020

Cited by 24 | Viewed by 3923

Abstract

Large segmental bone defects occurring after trauma, bone tumors, infections or revision surgeries are a challenge for surgeons. The aim of our study was to develop a new biomaterial utilizing simple and cheap 3D-printing techniques. A porous polylactide (PLA) cylinder was printed and [...] Read more.

Large segmental bone defects occurring after trauma, bone tumors, infections or revision surgeries are a challenge for surgeons. The aim of our study was to develop a new biomaterial utilizing simple and cheap 3D-printing techniques. A porous polylactide (PLA) cylinder was printed and functionalized with stromal-derived factor 1 (SDF-1) or bone morphogenetic protein 7 (BMP-7) immobilized in collagen type I. Biomechanical testing proved biomechanical stability and the scaffolds were implanted into a 6 mm critical size defect in rat femur. Bone growth was observed via x-ray and after 8 weeks, bone regeneration was analyzed with µCT and histological staining methods. Development of non-unions was detected in the control group with no implant. Implantation of PLA cylinder alone resulted in a slight but not significant osteoconductive effect, which was more pronounced in the group where the PLA cylinder was loaded with collagen type I. Addition of SDF-1 resulted in an osteoinductive effect, with stronger new bone formation. BMP-7 treatment showed the most distinct effect on bone regeneration. However, histological analyses revealed that newly formed bone in the BMP-7 group displayed a holey structure. Our results confirm the osteoinductive character of this 3D-biofabricated cell-free new biomaterial and raise new options for its application in bone tissue regeneration. Full article

(This article belongs to the Special Issue Biological Basis of Musculoskeletal Regeneration 2019)

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20 pages, 2595 KiB

Open AccessArticle

Degeneration of Lumbar Intervertebral Discs: Characterization of Anulus Fibrosus Tissue and Cells of Different Degeneration Grades

by Stefan Stich, Michal Jagielski, Anja Fleischmann, Carola Meier, Patricia Bussmann, Benjamin Kohl, Julia Schmidt, Jan-Philipp Krüger, Michaela Endres, Mario Cabraja, Kolja Reimann, Dominik Laue, Wolfgang Ertel and Michael Sittinger

Int. J. Mol. Sci. 2020, 21(6), 2165; https://doi.org/10.3390/ijms21062165 - 21 Mar 2020

Cited by 12 | Viewed by 4415

Abstract

Intervertebral disc (IVD) herniation and degeneration is a major source of back pain. In order to regenerate a herniated and degenerated disc, closure of the anulus fibrosus (AF) is of crucial importance. For molecular characterization of AF, genome-wide Affymetrix HG-U133plus2.0 microarrays of native [...] Read more.

Intervertebral disc (IVD) herniation and degeneration is a major source of back pain. In order to regenerate a herniated and degenerated disc, closure of the anulus fibrosus (AF) is of crucial importance. For molecular characterization of AF, genome-wide Affymetrix HG-U133plus2.0 microarrays of native AF and cultured cells were investigated. To evaluate if cells derived from degenerated AF are able to initiate gene expression of a regenerative pattern of extracellular matrix (ECM) molecules, cultivated cells were stimulated with bone morphogenetic protein 2 (BMP2), transforming growth factor β1 (TGFβ1) or tumor necrosis factor-α (TNFα) for 24 h. Comparative microarray analysis of native AF tissues showed 788 genes with a significantly different gene expression with 213 genes more highly expressed in mild and 575 genes in severe degenerated AF tissue. Mild degenerated native AF tissues showed a higher gene expression of common cartilage ECM genes, whereas severe degenerated AF tissues expressed genes known from degenerative processes, including matrix metalloproteinases (MMP) and bone associated genes. During monolayer cultivation, only 164 differentially expressed genes were found. The cells dedifferentiated and altered their gene expression profile. RTD-PCR analyses of BMP2- and TGFβ1-stimulated cells from mild and severe degenerated AF tissue after 24 h showed an increased expression of cartilage associated genes. TNFα stimulation increased MMP1, 3, and 13 expression. Cells derived from mild and severe degenerated tissues could be stimulated to a comparable extent. These results give hope that regeneration of mildly but also strongly degenerated disc tissue is possible. Full article

(This article belongs to the Special Issue Biological Basis of Musculoskeletal Regeneration 2019)

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12 pages, 3258 KiB

Open AccessArticle

Bioactive Glass (BG) ICIE16 Shows Promising Osteogenic Properties Compared to Crystallized 45S5-BG

by Fabian Westhauser, Frederike Hohenbild, Marcela Arango-Ospina, Sarah I. Schmitz, Sebastian Wilkesmann, Leena Hupa, Arash Moghaddam and Aldo R. Boccaccini

Int. J. Mol. Sci. 2020, 21(5), 1639; https://doi.org/10.3390/ijms21051639 - 28 Feb 2020

Cited by 39 | Viewed by 4010

Abstract

The ICIE16-bioactive glass (BG) (48.0 SiO₂, 6.6 Na₂O, 32.9 CaO, 2.5 P₂O₅, 10.0 K₂O (wt %)) has been developed as an alternative to 45S5-BG, the original BG composition (45.0 SiO₂, 24.5 [...] Read more.

The ICIE16-bioactive glass (BG) (48.0 SiO₂, 6.6 Na₂O, 32.9 CaO, 2.5 P₂O₅, 10.0 K₂O (wt %)) has been developed as an alternative to 45S5-BG, the original BG composition (45.0 SiO₂, 24.5 Na₂O, 24.5 CaO, 6.0 P₂O₅ (wt %)), with the intention of broadening the BG sintering window while maintaining bioactivity. Because there is a lack of reports on ICIE16-BG biological properties, the influence of ICIE16-BG on viability, proliferation, and osteogenic differentiation of human mesenchymal stromal cells (MSCs) was evaluated in direct comparison to 45S5-BG in this study. The BGs underwent heat treatment similar to that which is required in order to fabricate scaffolds by sintering, which resulted in crystallization of 45S5-BG (45S5-CBG) while ICIE16 remained amorphous. Granules based on both BGs were biocompatible, but ICIE16-BG was less harmful to cell viability, most likely due to a more pronounced pH alkalization in the 45S5-CBG group. ICIE16-BG outperformed 45S5-CBG in terms of osteogenic differentiation at the cellular level, as determined by the increased activity of alkaline phosphatase. However, granules from both BGs were comparable regarding the stimulation of expression levels of genes encoding for osseous extracellular matrix (ECM) proteins. The addition of therapeutically active ions to ICIE16-BG might further improve its ability to stimulate ECM production and should be investigated in upcoming studies. Full article

(This article belongs to the Special Issue Biological Basis of Musculoskeletal Regeneration 2019)

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16 pages, 2834 KiB

Open AccessArticle

Attenuation of Hypertrophy in Human MSCs via Treatment with a Retinoic Acid Receptor Inverse Agonist

by Moritz Riedl, Christina Witzmann, Matthias Koch, Siegmund Lang, Maximilian Kerschbaum, Florian Baumann, Werner Krutsch, Denitsa Docheva, Volker Alt and Christian Pfeifer

Int. J. Mol. Sci. 2020, 21(4), 1444; https://doi.org/10.3390/ijms21041444 - 20 Feb 2020

Cited by 10 | Viewed by 4235

Abstract

In vitro chondrogenically differentiated mesenchymal stem cells (MSCs) have a tendency to undergo hypertrophy, mirroring the fate of transient “chondrocytes” in the growth plate. As hypertrophy would result in ossification, this fact limits their use in cartilage tissue engineering applications. During limb development, [...] Read more.

In vitro chondrogenically differentiated mesenchymal stem cells (MSCs) have a tendency to undergo hypertrophy, mirroring the fate of transient “chondrocytes” in the growth plate. As hypertrophy would result in ossification, this fact limits their use in cartilage tissue engineering applications. During limb development, retinoic acid receptor (RAR) signaling exerts an important influence on cell fate of mesenchymal progenitors. While retinoids foster hypertrophy, suppression of RAR signaling seems to be required for chondrogenic differentiation. Therefore, we hypothesized that treatment of chondrogenically differentiating hMSCs with the RAR inverse agonist, BMS204,493 (further named BMS), would attenuate hypertrophy. We induced hypertrophy in chondrogenic precultured MSC pellets by the addition of bone morphogenetic protein 4. Direct activation of the RAR pathway by application of the physiological RAR agonist retinoic acid (RA) further enhanced the hypertrophic phenotype. However, BMS treatment reduced hypertrophic conversion in hMSCs, shown by decreased cell size, number of hypertrophic cells, and collagen type X deposition in histological analyses. BMS effects were dependent on the time point of application and strongest after early treatment during chondrogenic precultivation. The possibility of modifing hypertrophic cartilage via attenuation of RAR signaling by BMS could be helpful in producing stable engineered tissue for cartilage regeneration. Full article

(This article belongs to the Special Issue Biological Basis of Musculoskeletal Regeneration 2019)

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10 pages, 2730 KiB

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Assessment of Bones Deficient in Fibrillin-1 Microfibrils Reveals Pronounced Sex Differences

by Lukas Altinbas, Nicole Bormann, Daniel Lehmann, Sarah Jeuthe, Dag Wulsten, Uwe Kornak, Peter N. Robinson, Britt Wildemann and Georgios Kararigas

Int. J. Mol. Sci. 2019, 20(23), 6059; https://doi.org/10.3390/ijms20236059 - 1 Dec 2019

Cited by 11 | Viewed by 3205

Abstract

Defects in the extracellular matrix protein fibrillin-1 that perturb transforming growth factor beta (TGFβ) bioavailability lead to Marfan syndrome (MFS). MFS is an autosomal-dominant disorder, which is associated with connective tissue and skeletal defects, among others. To date, it is unclear how biological [...] Read more.

Defects in the extracellular matrix protein fibrillin-1 that perturb transforming growth factor beta (TGFβ) bioavailability lead to Marfan syndrome (MFS). MFS is an autosomal-dominant disorder, which is associated with connective tissue and skeletal defects, among others. To date, it is unclear how biological sex impacts the structural and functional properties of bone in MFS. The aim of this study was to investigate the effects of sex on bone microarchitecture and mechanical properties in mice with deficient fibrillin-1, a model of human MFS. Bones of 11-week-old male and female Fbn1^mgR/mgR mice were investigated. Three-dimensional micro-computed tomography of femora and vertebrae revealed a lower ratio of trabecular bone volume to tissue volume, reduced trabecular number and thickness, and greater trabecular separation in females vs. males. Three-point bending of femora revealed significantly lower post-yield displacement and work-to-fracture in females vs. males. Mechanistically, we found higher Smad2 and ERK1/2 phosphorylation in females vs. males, demonstrating a greater activation of TGFβ signaling in females. In summary, the present findings show pronounced sex differences in the matrix and function of bones deficient in fibrillin-1 microfibrils. Consequently, sex-specific analysis of bone characteristics in patients with MFS may prove useful in improving the clinical management and life quality of these patients, through the development of sex-specific therapeutic approaches. Full article

(This article belongs to the Special Issue Biological Basis of Musculoskeletal Regeneration 2019)

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22 pages, 7927 KiB

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Migrating Myofibroblastic Iliotibial Band-Derived Fibroblasts Represent a Promising Cell Source for Ligament Reconstruction

by Silke Schwarz, Clemens Gögele, Benjamin Ondruschka, Niels Hammer, Benjamin Kohl and Gundula Schulze-Tanzil

Int. J. Mol. Sci. 2019, 20(8), 1972; https://doi.org/10.3390/ijms20081972 - 22 Apr 2019

Cited by 16 | Viewed by 4261

Abstract

The iliotibial band (ITB) is a suitable scaffold for anterior cruciate ligament (ACL) reconstruction, providing a sufficient mechanical resistance to loading. Hence, ITB-derived fibroblasts attract interest for ligament tissue engineering but have so far not been characterized. This present study aimed at characterizing [...] Read more.

The iliotibial band (ITB) is a suitable scaffold for anterior cruciate ligament (ACL) reconstruction, providing a sufficient mechanical resistance to loading. Hence, ITB-derived fibroblasts attract interest for ligament tissue engineering but have so far not been characterized. This present study aimed at characterizing ITB fibroblasts before, during, and after emigration from cadaveric ITB explants to decipher the emigration behavior and to utilize their migratory capacity for seeding biomaterials. ITB and, for comparison, ACL tissues were assessed for the content of alpha smooth muscle actin (αSMA) expressing fibroblasts and degeneration. The cell survival and αSMA expression were monitored in explants used for cell isolation, monolayer, self-assembled ITB spheroids, and spheroids seeded in polyglycolic acid (PGA) scaffolds. The protein expression profile of targets typically expressed by ligamentocytes (collagen types I–III, elastin, lubricin, decorin, aggrecan, fibronectin, tenascin C, CD44, β1-integrins, vimentin, F-actin, αSMA, and vascular endothelial growth factor A [VEGFA]) was compared between ITB and ACL fibroblasts. A donor- and age-dependent differing percentage of αSMA positive cells could be detected, which was similar in ITB and ACL tissues despite the grade of degeneration being significantly higher in the ACL due to harvesting them from OA knees. ITB fibroblasts survived for several months in an explant culture, continuously forming monolayers with VEGFA and an increased αSMA expression. They shared their expression profile with ACL fibroblasts. αSMA decreased during the monolayer to spheroid/scaffold transition. Using self-assembled spheroids, the migratory capacity of reversible myofibroblastic ITB cells can be utilized for colonizing biomaterials for ACL tissue engineering and to support ligament healing. Full article

(This article belongs to the Special Issue Biological Basis of Musculoskeletal Regeneration 2019)

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16 pages, 3281 KiB

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Chondrocyte Culture Parameters for Matrix-Assisted Autologous Chondrocyte Implantation Affect Catabolism and Inflammation in a Rabbit Model

by Martin Sauerschnig, Markus T. Berninger, Theresa Kaltenhauser, Michael Plecko, Gabriele Wexel, Martin Schönfelder, Valerie Wienerroither, Andreas B. Imhoff, Philip B. Schöttle, Elizabeth Rosado Balmayor and Gian M. Salzmann

Int. J. Mol. Sci. 2019, 20(7), 1545; https://doi.org/10.3390/ijms20071545 - 27 Mar 2019

Cited by 2 | Viewed by 3561

Abstract

Cartilage defects represent an increasing pathology among active individuals that affects the ability to contribute to sports and daily life. Cell therapy, such as autologous chondrocyte implantation (ACI), is a widespread option to treat larger cartilage defects still lacking standardization of in vitro [...] Read more.

Cartilage defects represent an increasing pathology among active individuals that affects the ability to contribute to sports and daily life. Cell therapy, such as autologous chondrocyte implantation (ACI), is a widespread option to treat larger cartilage defects still lacking standardization of in vitro cell culture parameters. We hypothesize that mRNA expression of cytokines and proteases before and after ACI is influenced by in vitro parameters: cell-passage, cell-density and membrane-holding time. Knee joint articular chondrocytes, harvested from rabbits (n = 60), were cultured/processed under varying conditions: after three different cell-passages (P1, P3, and P5), cells were seeded on 3D collagen matrices (approximately 25 mm³) at three different densities (2 × 10⁵/matrix, 1 × 10⁶/matrix, and 3 × 10⁶/matrix) combined with two different membrane-holding times (5 h and two weeks) prior autologous transplantation. Those combinations resulted in 18 different in vivo experimental groups. Two defects/knee/animal were created in the trochlear groove (defect dimension: ∅ 4 mm × 2 mm). Four identical cell-seeded matrices (CSM) were assembled and grouped in two pairs: One pair giving pre-operative in vitro data (CSM-i), the other pair was implanted in vivo and harvested 12 weeks post-implantation (CSM-e). CSMs were analyzed for TNF-α, IL-1β, MMP-1, and MMP-3 via qPCR. CSM-i showed higher expression of IL-1β, MMP-1, and MMP-3 compared to CSM-e. TNF-α expression was higher in CSM-e. Linearity between CSM-i and CSM-e values was found, except for TNF-α. IL-1β expression was higher in CSM-i at higher passage and longer membrane-holding time. IL-1β expression decreased with prolonged membrane-holding time in CSM-e. For TNF-α, the reverse was true. Lower cell-passages and lower membrane-holding time resulted in stronger TNF-α expression. Prolonged membrane-holding time resulted in increased MMP levels among CSM-i and CSM-e. Cellular density was of no significant effect. We demonstrated cytokine and MMP expression levels to be directly influenced by in vitro culture settings in ACI. Linearity of expression-patterns between CSM-i and CSM-e may predict ACI regeneration outcome in vivo. Cytokine/protease interaction within the regenerate tissue could be guided via adjusting in vitro culture parameters, of which membrane-holding time resulted the most relevant one. Full article

(This article belongs to the Special Issue Biological Basis of Musculoskeletal Regeneration 2019)

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Review

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40 pages, 919 KiB

Open AccessReview

Crosstalk of Brain and Bone—Clinical Observations and Their Molecular Bases

by Ellen Otto, Paul-Richard Knapstein, Denise Jahn, Jessika Appelt, Karl-Heinz Frosch, Serafeim Tsitsilonis and Johannes Keller

Int. J. Mol. Sci. 2020, 21(14), 4946; https://doi.org/10.3390/ijms21144946 - 13 Jul 2020

Cited by 47 | Viewed by 6653

Abstract

As brain and bone disorders represent major health issues worldwide, substantial clinical investigations demonstrated a bidirectional crosstalk on several levels, mechanistically linking both apparently unrelated organs. While multiple stress, mood and neurodegenerative brain disorders are associated with osteoporosis, rare genetic skeletal diseases display [...] Read more.

As brain and bone disorders represent major health issues worldwide, substantial clinical investigations demonstrated a bidirectional crosstalk on several levels, mechanistically linking both apparently unrelated organs. While multiple stress, mood and neurodegenerative brain disorders are associated with osteoporosis, rare genetic skeletal diseases display impaired brain development and function. Along with brain and bone pathologies, particularly trauma events highlight the strong interaction of both organs. This review summarizes clinical and experimental observations reported for the crosstalk of brain and bone, followed by a detailed overview of their molecular bases. While brain-derived molecules affecting bone include central regulators, transmitters of the sympathetic, parasympathetic and sensory nervous system, bone-derived mediators altering brain function are released from bone cells and the bone marrow. Although the main pathways of the brain-bone crosstalk remain ‘efferent’, signaling from brain to bone, this review emphasizes the emergence of bone as a crucial ‘afferent’ regulator of cerebral development, function and pathophysiology. Therefore, unraveling the physiological and pathological bases of brain-bone interactions revealed promising pharmacologic targets and novel treatment strategies promoting concurrent brain and bone recovery. Full article

(This article belongs to the Special Issue Biological Basis of Musculoskeletal Regeneration 2019)

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22 pages, 378 KiB

Open AccessReview

PRP and BMAC for Musculoskeletal Conditions via Biomaterial Carriers

by Fabio S. M. Yamaguchi, Shahin Shams, Eduardo A. Silva and Roberta S. Stilhano

Int. J. Mol. Sci. 2019, 20(21), 5328; https://doi.org/10.3390/ijms20215328 - 25 Oct 2019

Cited by 18 | Viewed by 6939

Abstract

Platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC) are orthobiologic therapies considered as an alternative to the current therapies for muscle, bone and cartilage. Different formulations of biomaterials have been used as carriers for PRP and BMAC in order to increase regenerative [...] Read more.

Platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC) are orthobiologic therapies considered as an alternative to the current therapies for muscle, bone and cartilage. Different formulations of biomaterials have been used as carriers for PRP and BMAC in order to increase regenerative processes. The most common biomaterials utilized in conjunction with PRP and BMAC clinical trials are organic scaffolds and natural or synthetic polymers. This review will cover the combinatorial strategies of biomaterial carriers with PRP and BMAC for musculoskeletal conditions (MsCs) repair and regeneration in clinical trials. The main objective is to review the therapeutic use of PRP and BMAC as a treatment option for muscle, bone and cartilage injuries. Full article

(This article belongs to the Special Issue Biological Basis of Musculoskeletal Regeneration 2019)

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