The Role of Hyaluronic Acid in Cartilage Boundary Lubrication
Hydration lubrication has emerged as a new paradigm for lubrication in aqueous and biological media, accounting especially for the extremely low friction (friction coefficients down to 0.001) of articular cartilage lubrication in joints. Among the ensemble of molecules acting in the joint, phosphati...
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MDPI AG
2020-07-01
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| Series: | Cells |
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| Online Access: | https://www.mdpi.com/2073-4409/9/7/1606 |
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| author | Weifeng Lin Zhang Liu Nir Kampf Jacob Klein |
| author_facet | Weifeng Lin Zhang Liu Nir Kampf Jacob Klein |
| author_sort | Weifeng Lin |
| collection | DOAJ |
| description | Hydration lubrication has emerged as a new paradigm for lubrication in aqueous and biological media, accounting especially for the extremely low friction (friction coefficients down to 0.001) of articular cartilage lubrication in joints. Among the ensemble of molecules acting in the joint, phosphatidylcholine (PC) lipids have been proposed as the key molecules forming, in a complex with other molecules including hyaluronic acid (HA), a robust layer on the outer surface of the cartilage. HA, ubiquitous in synovial joints, is not in itself a good boundary lubricant, but binds the PC lipids at the cartilage surface; these, in turn, massively reduce the friction via hydration lubrication at their exposed, highly hydrated phosphocholine headgroups. An important unresolved issue in this scenario is why the free HA molecules in the synovial fluid do not suppress the lubricity by adsorbing simultaneously to the opposing lipid layers, i.e., forming an adhesive, dissipative bridge between them, as they slide past each other during joint articulation. To address this question, we directly examined the friction between two hydrogenated soy PC (HSPC) lipid layers (in the form of liposomes) immersed in HA solution or two palmitoyl–oleoyl PC (POPC) lipid layers across HA–POPC solution using a surface force balance (SFB). The results show, clearly and surprisingly, that HA addition does not affect the outstanding lubrication provided by the PC lipid layers. A possible mechanism indicated by our data that may account for this is that multiple lipid layers form on each cartilage surface, so that the slip plane may move from the midplane between the opposing surfaces, which is bridged by the HA, to an HA-free interface within a multilayer, where hydration lubrication is freely active. Another possibility suggested by our model experiments is that lipids in synovial fluid may complex with HA, thereby inhibiting the HA molecules from adhering to the lipids on the cartilage surfaces. |
| first_indexed | 2024-03-10T18:43:10Z |
| format | Article |
| id | doaj.art-0292f3102fa047f0b606485989aa6def |
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| issn | 2073-4409 |
| language | English |
| last_indexed | 2024-03-10T18:43:10Z |
| publishDate | 2020-07-01 |
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| series | Cells |
| spelling | doaj.art-0292f3102fa047f0b606485989aa6def2023-11-20T05:42:14ZengMDPI AGCells2073-44092020-07-0197160610.3390/cells9071606The Role of Hyaluronic Acid in Cartilage Boundary LubricationWeifeng Lin0Zhang Liu1Nir Kampf2Jacob Klein3Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, IsraelDepartment of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, IsraelDepartment of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, IsraelDepartment of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, IsraelHydration lubrication has emerged as a new paradigm for lubrication in aqueous and biological media, accounting especially for the extremely low friction (friction coefficients down to 0.001) of articular cartilage lubrication in joints. Among the ensemble of molecules acting in the joint, phosphatidylcholine (PC) lipids have been proposed as the key molecules forming, in a complex with other molecules including hyaluronic acid (HA), a robust layer on the outer surface of the cartilage. HA, ubiquitous in synovial joints, is not in itself a good boundary lubricant, but binds the PC lipids at the cartilage surface; these, in turn, massively reduce the friction via hydration lubrication at their exposed, highly hydrated phosphocholine headgroups. An important unresolved issue in this scenario is why the free HA molecules in the synovial fluid do not suppress the lubricity by adsorbing simultaneously to the opposing lipid layers, i.e., forming an adhesive, dissipative bridge between them, as they slide past each other during joint articulation. To address this question, we directly examined the friction between two hydrogenated soy PC (HSPC) lipid layers (in the form of liposomes) immersed in HA solution or two palmitoyl–oleoyl PC (POPC) lipid layers across HA–POPC solution using a surface force balance (SFB). The results show, clearly and surprisingly, that HA addition does not affect the outstanding lubrication provided by the PC lipid layers. A possible mechanism indicated by our data that may account for this is that multiple lipid layers form on each cartilage surface, so that the slip plane may move from the midplane between the opposing surfaces, which is bridged by the HA, to an HA-free interface within a multilayer, where hydration lubrication is freely active. Another possibility suggested by our model experiments is that lipids in synovial fluid may complex with HA, thereby inhibiting the HA molecules from adhering to the lipids on the cartilage surfaces.https://www.mdpi.com/2073-4409/9/7/1606hyaluronic acidphosphatidylcholine lipidscartilage lubricationhydration lubricationpolymer bridging |
| spellingShingle | Weifeng Lin Zhang Liu Nir Kampf Jacob Klein The Role of Hyaluronic Acid in Cartilage Boundary Lubrication Cells hyaluronic acid phosphatidylcholine lipids cartilage lubrication hydration lubrication polymer bridging |
| title | The Role of Hyaluronic Acid in Cartilage Boundary Lubrication |
| title_full | The Role of Hyaluronic Acid in Cartilage Boundary Lubrication |
| title_fullStr | The Role of Hyaluronic Acid in Cartilage Boundary Lubrication |
| title_full_unstemmed | The Role of Hyaluronic Acid in Cartilage Boundary Lubrication |
| title_short | The Role of Hyaluronic Acid in Cartilage Boundary Lubrication |
| title_sort | role of hyaluronic acid in cartilage boundary lubrication |
| topic | hyaluronic acid phosphatidylcholine lipids cartilage lubrication hydration lubrication polymer bridging |
| url | https://www.mdpi.com/2073-4409/9/7/1606 |
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