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Tendon proper- and peritenon-derived progenitor cells have unique tenogenic properties.

Mienaltowski MJ, Adams SM, Birk DE - Stem Cell Res Ther (2014)

Bottom Line: Tendon construct ultrastructure was also compared after 45 days.It also was found that peritenon-derived progenitors secrete factor(s) stimulatory to tenocytes and tendon proper progenitors.Data demonstrate that, relative to peritenon-derived progenitors, tendon proper progenitors have greater potential for forming functional tendon-like tissue.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Introduction: Multipotent progenitor populations exist within the tendon proper and peritenon of the Achilles tendon. Progenitor populations derived from the tendon proper and peritenon are enriched with distinct cell types that are distinguished by expression of markers of tendon and vascular or pericyte origins, respectively. The objective of this study was to discern the unique tenogenic properties of tendon proper- and peritenon-derived progenitors within an in vitro model. We hypothesized that progenitors from each region contribute differently to tendon formation; thus, when incorporated into a regenerative model, progenitors from each region will respond uniquely. Moreover, we hypothesized that cell populations like progenitors were capable of stimulating tenogenic differentiation, so we generated conditioned media from these cell types to analyze their stimulatory potentials.

Methods: Isolated progenitors were seeded within fibrinogen/thrombin gel-based constructs with or without supplementation with recombinant growth/differentiation factor-5 (GDF5). Early and late in culture, gene expression of differentiation markers and matrix assembly genes was analyzed. Tendon construct ultrastructure was also compared after 45 days. Moreover, conditioned media from tendon proper-derived progenitors, peritenon-derived progenitors, or tenocytes was applied to each of the three cell types to determine paracrine stimulatory effects of the factors secreted from each of the respective cell types.

Results: The cell orientation, extracellular domain and fibril organization of constructs were comparable to embryonic tendon. The tendon proper-derived progenitors produced a more tendon-like construct than the peritenon-derived progenitors. Seeded tendon proper-derived progenitors expressed greater levels of tenogenic markers and matrix assembly genes, relative to peritenon-derived progenitors. However, GDF5 supplementation improved expression of matrix assembly genes in peritenon progenitors and structurally led to increased mean fibril diameters. It also was found that peritenon-derived progenitors secrete factor(s) stimulatory to tenocytes and tendon proper progenitors.

Conclusions: Data demonstrate that, relative to peritenon-derived progenitors, tendon proper progenitors have greater potential for forming functional tendon-like tissue. Furthermore, factors secreted by peritenon-derived progenitors suggest a trophic role for this cell type as well. Thus, these findings highlight the synergistic potential of including these progenitor populations in restorative tendon engineering strategies.

No MeSH data available.


Mean fibril diameters for constructs were similar to embryonic tendon, and supplemented GDF5 improved peritenon progenitor-derived construct mean fibril diameters. Fibril diameters of tendon proper progenitor-seeded (TP) constructs were greater than those of the peritenon-derived progenitor (PERI) constructs as well as those of embryonic Achilles tendon (E15 to E17) (A). Supplementation with GDF5 increased fibril diameters within PERI constructs (B) but not TP constructs. For each group, the mean fibril diameters with 95% confidence interval (CI) are compared (C), and fibril diameter analyses are also given for each group (D) – mean fibril diameters ± standard deviation, median, first and third quartiles. Significant differences are demonstrated via t-test statistical analyses of fibrils analyzed in each group’s images (E). Replicates (n) represent each image analyzed per group: E15 to E17, n = 32; TP, n = 64; TP + GDF5, n = 32; PERI, n = 32; PERI + GDF5, n = 24. E, embryonic day; GDF5, growth differentiation factor 5.
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Figure 3: Mean fibril diameters for constructs were similar to embryonic tendon, and supplemented GDF5 improved peritenon progenitor-derived construct mean fibril diameters. Fibril diameters of tendon proper progenitor-seeded (TP) constructs were greater than those of the peritenon-derived progenitor (PERI) constructs as well as those of embryonic Achilles tendon (E15 to E17) (A). Supplementation with GDF5 increased fibril diameters within PERI constructs (B) but not TP constructs. For each group, the mean fibril diameters with 95% confidence interval (CI) are compared (C), and fibril diameter analyses are also given for each group (D) – mean fibril diameters ± standard deviation, median, first and third quartiles. Significant differences are demonstrated via t-test statistical analyses of fibrils analyzed in each group’s images (E). Replicates (n) represent each image analyzed per group: E15 to E17, n = 32; TP, n = 64; TP + GDF5, n = 32; PERI, n = 32; PERI + GDF5, n = 24. E, embryonic day; GDF5, growth differentiation factor 5.

Mentions: An analysis of fibril diameters generated within the constructs revealed that overall both progenitor populations assembled fibrils with embryonic tendon-like features, that is, unimodal diameter distributions with homogeneous small diameters. Fibrils assembled by the tendon proper-derived progenitors demonstrated a broader diameter distribution shifted to larger diameters than in the embryonic tendon with larger mean diameters (37.2 ± 6.7 nm versus 32.8 ± 4.7 nm, mean ± sd, P <0.001) (Figure 3A,D,E). The peritenon-derived progenitor distribution was shifted to smaller diameters (29.1 ± 6.9 nm, P = 0.002) (Figure 3A, D,E). However, when GDF5 is supplemented, peritenon-derived progenitors produce fibrils with a mean diameter distribution (31.8 ± 4.7 nm) comparable to that of embryonic tendon (P = 0.196; Figure 3B,D,E) and no change in the fibril diameters (37.8 ± 4.7 nm) is noted for tendon proper-derived progenitors (P = 0.959; Figure 3B,D,E).


Tendon proper- and peritenon-derived progenitor cells have unique tenogenic properties.

Mienaltowski MJ, Adams SM, Birk DE - Stem Cell Res Ther (2014)

Mean fibril diameters for constructs were similar to embryonic tendon, and supplemented GDF5 improved peritenon progenitor-derived construct mean fibril diameters. Fibril diameters of tendon proper progenitor-seeded (TP) constructs were greater than those of the peritenon-derived progenitor (PERI) constructs as well as those of embryonic Achilles tendon (E15 to E17) (A). Supplementation with GDF5 increased fibril diameters within PERI constructs (B) but not TP constructs. For each group, the mean fibril diameters with 95% confidence interval (CI) are compared (C), and fibril diameter analyses are also given for each group (D) – mean fibril diameters ± standard deviation, median, first and third quartiles. Significant differences are demonstrated via t-test statistical analyses of fibrils analyzed in each group’s images (E). Replicates (n) represent each image analyzed per group: E15 to E17, n = 32; TP, n = 64; TP + GDF5, n = 32; PERI, n = 32; PERI + GDF5, n = 24. E, embryonic day; GDF5, growth differentiation factor 5.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 3: Mean fibril diameters for constructs were similar to embryonic tendon, and supplemented GDF5 improved peritenon progenitor-derived construct mean fibril diameters. Fibril diameters of tendon proper progenitor-seeded (TP) constructs were greater than those of the peritenon-derived progenitor (PERI) constructs as well as those of embryonic Achilles tendon (E15 to E17) (A). Supplementation with GDF5 increased fibril diameters within PERI constructs (B) but not TP constructs. For each group, the mean fibril diameters with 95% confidence interval (CI) are compared (C), and fibril diameter analyses are also given for each group (D) – mean fibril diameters ± standard deviation, median, first and third quartiles. Significant differences are demonstrated via t-test statistical analyses of fibrils analyzed in each group’s images (E). Replicates (n) represent each image analyzed per group: E15 to E17, n = 32; TP, n = 64; TP + GDF5, n = 32; PERI, n = 32; PERI + GDF5, n = 24. E, embryonic day; GDF5, growth differentiation factor 5.
Mentions: An analysis of fibril diameters generated within the constructs revealed that overall both progenitor populations assembled fibrils with embryonic tendon-like features, that is, unimodal diameter distributions with homogeneous small diameters. Fibrils assembled by the tendon proper-derived progenitors demonstrated a broader diameter distribution shifted to larger diameters than in the embryonic tendon with larger mean diameters (37.2 ± 6.7 nm versus 32.8 ± 4.7 nm, mean ± sd, P <0.001) (Figure 3A,D,E). The peritenon-derived progenitor distribution was shifted to smaller diameters (29.1 ± 6.9 nm, P = 0.002) (Figure 3A, D,E). However, when GDF5 is supplemented, peritenon-derived progenitors produce fibrils with a mean diameter distribution (31.8 ± 4.7 nm) comparable to that of embryonic tendon (P = 0.196; Figure 3B,D,E) and no change in the fibril diameters (37.8 ± 4.7 nm) is noted for tendon proper-derived progenitors (P = 0.959; Figure 3B,D,E).

Bottom Line: Tendon construct ultrastructure was also compared after 45 days.It also was found that peritenon-derived progenitors secrete factor(s) stimulatory to tenocytes and tendon proper progenitors.Data demonstrate that, relative to peritenon-derived progenitors, tendon proper progenitors have greater potential for forming functional tendon-like tissue.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Introduction: Multipotent progenitor populations exist within the tendon proper and peritenon of the Achilles tendon. Progenitor populations derived from the tendon proper and peritenon are enriched with distinct cell types that are distinguished by expression of markers of tendon and vascular or pericyte origins, respectively. The objective of this study was to discern the unique tenogenic properties of tendon proper- and peritenon-derived progenitors within an in vitro model. We hypothesized that progenitors from each region contribute differently to tendon formation; thus, when incorporated into a regenerative model, progenitors from each region will respond uniquely. Moreover, we hypothesized that cell populations like progenitors were capable of stimulating tenogenic differentiation, so we generated conditioned media from these cell types to analyze their stimulatory potentials.

Methods: Isolated progenitors were seeded within fibrinogen/thrombin gel-based constructs with or without supplementation with recombinant growth/differentiation factor-5 (GDF5). Early and late in culture, gene expression of differentiation markers and matrix assembly genes was analyzed. Tendon construct ultrastructure was also compared after 45 days. Moreover, conditioned media from tendon proper-derived progenitors, peritenon-derived progenitors, or tenocytes was applied to each of the three cell types to determine paracrine stimulatory effects of the factors secreted from each of the respective cell types.

Results: The cell orientation, extracellular domain and fibril organization of constructs were comparable to embryonic tendon. The tendon proper-derived progenitors produced a more tendon-like construct than the peritenon-derived progenitors. Seeded tendon proper-derived progenitors expressed greater levels of tenogenic markers and matrix assembly genes, relative to peritenon-derived progenitors. However, GDF5 supplementation improved expression of matrix assembly genes in peritenon progenitors and structurally led to increased mean fibril diameters. It also was found that peritenon-derived progenitors secrete factor(s) stimulatory to tenocytes and tendon proper progenitors.

Conclusions: Data demonstrate that, relative to peritenon-derived progenitors, tendon proper progenitors have greater potential for forming functional tendon-like tissue. Furthermore, factors secreted by peritenon-derived progenitors suggest a trophic role for this cell type as well. Thus, these findings highlight the synergistic potential of including these progenitor populations in restorative tendon engineering strategies.

No MeSH data available.