Toughening mechanisms for the attachment of architectured materials: The mechanics of the tendon enthesis

Golman, Mikhail; Abraham, Adam C.; Kurtaliaj, Iden; Marshall, Brittany P.; Hu, Yizhong; Schwartz, Andrea G.; Guo, Xing; Birman, Victor; Thurner, Philipp J.; Genin, Guy M.; Thomopoulos, Stavros

doi:10.1101/2021.05.17.444505

Cited by 4 publications

(4 citation statements)

References 62 publications

(54 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…50 Thus, in our study, the strain likely deviated to the weakest area of the sample, leading to failure within the bone. This observation is in line with the avulsion fractures described by Deymier et al ( 2019) and Golman et al (2021) 51 at the supraspinatus tendon insertion following monotonic uniaxial tensile loading in mice, where the supraspinatus muscle had been paralyzed by treatment with botulinum toxin. In the latter study, in contrast to our study, it has been reported a decreased maximum load in response to unloading, positively correlated with a decrease in bone architectural parameters, such as trabecular and cortical thicknesses, BV/TV, or bone mineral density.…”

Section: Discussionsupporting

confidence: 89%

Effects of hindlimb unloading and subsequent reloading on the structure and mechanical properties of Achilles tendon‐to‐bone attachment

et al. 2022

View full text Add to dashboard Cite

While muscle and bone adaptations to deconditioning have been widely described, few studies have focused on the tendon enthesis. Our study examined the effects of mechanical loading on the structure and mechanical properties of the Achilles tendon enthesis. We assessed the fibrocartilage surface area, the organization of collagen, the expression of collagen II, the presence of osteoclasts, and the tensile properties of the mouse enthesis both after 14 days of hindlimb suspension (HU) and after a subsequent 6 days of reloading. Although soleus atrophy was severe after HU, calcified fibrocartilage (CFc) was a little affected.In contrast, we observed a decrease in non-calcified fibrocartilage (UFc) surface area, collagen fiber disorganization, modification of morphological characteristics of the fibrocartilage cells, and altered collagen II distribution. Compared to the control group, restoring normal loads increased both UFc surface area and expression of collagen II, and led to a crimp pattern in collagen. Reloading induced an increase in CFc surface area, probably due to the mineralization front advancing toward the tendon. Functionally, unloading resulted in decreased enthesis stiffness and a shift in site of failure from the osteochondral interface to the bone, whereas 6 days of reloading restored the original elastic properties and site of failure. In the context of spaceflight, our results suggest that care must be taken when performing countermeasure exercises both during missions and during the return to Earth.

show abstract

Section: Discussionsupporting

confidence: 89%

Effects of hindlimb unloading and subsequent reloading on the structure and mechanical properties of Achilles tendon‐to‐bone attachment

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Others have also shown that disruption of the mineral matrix can significantly reduce the tensile strength of the enthesis. 28,29 Surprisingly, despite the thinner mineral thickness at the adult supraspinatus and Achilles entheses, Fgf9 ScxCre mice had increased cellular density at the attachment site. Previously, increased mesenchymal cellularity has been linked to the delayed palatal growth in embryos with global deletion of Fgf9.…”

Section: Discussionmentioning

confidence: 99%

Targeted deletion of Fgf9 in tendon disrupts mineralization of the developing enthesis

et al. 2023

View full text Add to dashboard Cite

The enthesis is a transitional tissue between tendon and bone that matures postnatally. The development and maturation of the enthesis involve cellular processes likened to an arrested growth plate. In this study, we explored the role of fibroblast growth factor 9 (Fgf9), a known regulator of chondrogenesis and vascularization during bone development, on the structure and function of the postnatal enthesis. First, we confirmed spatial expression of Fgf9 in the tendon and enthesis using in situ hybridization. We then used Cre‐lox recombinase to conditionally knockout Fgf9 in mouse tendon and enthesis (Scx‐Cre) and characterized enthesis morphology as well as mechanical properties in Fgf9ScxCre and wild‐type (WT) entheses. Fgf9ScxCre mice had smaller calcaneal and humeral apophyses, thinner cortical bone at the attachment, increased cellularity, and reduced failure load in mature entheses compared to WT littermates. During postnatal development, we found reduced chondrocyte hypertrophy and disrupted type X collagen (Col X) in Fgf9ScxCre entheses. These findings support that tendon‐derived Fgf9 is important for functional development of the enthesis, including its postnatal mineralization. Our findings suggest the potential role of FGF signaling during enthesis development.

show abstract

“…Others have also shown that disruption of the mineral matrix can significantly reduce the tensile strength of the enthesis. 31,32 Surprisingly, despite the thinner mineralized bone at the adult supraspinatus and Achilles entheses, Fgf9 ScxCre mice had increased cellular density at the attachment site. Previously, increased mesenchymal cellularity has been linked to the delayed palatal growth in embryos with global deletion of Fgf9 .…”

Section: Discussionmentioning

confidence: 99%

Targeted Deletion of Fgf9 in Tendon Disrupts Mineralization of the Developing Enthesis

Ganji

Leek

Duncan

et al. 2022

Preprint

View full text Add to dashboard Cite

The enthesis is a transitional tissue between tendon and bone that matures postnatally. The development and maturation of the enthesis involve cellular processes likened to an arrested growth plate. In this study, we explored the role of fibroblast growth factor 9 (Fgf9), a known regulator of chondrogenesis and vascularization during bone development, on the structure and function of the postnatal enthesis. First, we confirmed spatial expression of Fgf9 in wildtype tendon and enthesis using in situ hybridization. We then used Cre recombinase driven by the scleraxis promoter (ScxCre) to conditionally inactivate Fgf9 in mouse tendon and enthesis. Characterization of enthesis morphology and mechanical properties in Fgf9ScxCre and wildtype (WT) entheses showed a smaller calcaneal and humeral apophyses, thinner cortical bone at the attachment, increased cellularity, and reduced failure load in mature entheses in Fgf9ScxCre compared to WT littermates. During postnatal development, we found reduced chondrocyte hypertrophy and disrupted type X collagen (Col X) in Fgf9ScxCre entheses. These findings support a model in which tendon-derived Fgf9 regulates the functional development of the enthesis, including its postnatal mineralization.

show abstract

Toughening mechanisms for the attachment of architectured materials: The mechanics of the tendon enthesis

Cited by 4 publications

References 62 publications

Effects of hindlimb unloading and subsequent reloading on the structure and mechanical properties of Achilles tendon‐to‐bone attachment

Effects of hindlimb unloading and subsequent reloading on the structure and mechanical properties of Achilles tendon‐to‐bone attachment

Targeted deletion of Fgf9 in tendon disrupts mineralization of the developing enthesis

Targeted Deletion of Fgf9 in Tendon Disrupts Mineralization of the Developing Enthesis

Contact Info

Product

Resources

About