Are There Any Differences in the Healing Capacity between the Medial Collateral Ligament’s (MCL) Proximal and Distal Parts in the Human Knee? Quantitative and Immunohistochemical Analysis of CD34, α-Smooth Muscle Actin (α-SMA), and Vascular Endothelial Growth Factor (VEGF) Expression Regarding the Epiligament (EL) Theory
The human knee is a complex joint that comprises several ligaments, including the medial collateral ligament (MCL). The MCL provides stability to the knee and helps prevent its excessive inward movement. The MCL also has a thin layer of connective tissue known as the epiligament (EL), which adheres...
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MDPI AG
2024-03-01
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| Series: | Biomedicines |
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| Online Access: | https://www.mdpi.com/2227-9059/12/3/659 |
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| author | Georgi P. Georgiev Yordan Yordanov Lyubomir Gaydarski Richard Shane Tubbs Łukasz Olewnik Nicol Zielinska Maria Piagkou Julian Ananiev Iva N. Dimitrova Svetoslav A. Slavchev Ivan Terziev Athikhun Suwannakhan Boycho Landzhov |
| author_facet | Georgi P. Georgiev Yordan Yordanov Lyubomir Gaydarski Richard Shane Tubbs Łukasz Olewnik Nicol Zielinska Maria Piagkou Julian Ananiev Iva N. Dimitrova Svetoslav A. Slavchev Ivan Terziev Athikhun Suwannakhan Boycho Landzhov |
| author_sort | Georgi P. Georgiev |
| collection | DOAJ |
| description | The human knee is a complex joint that comprises several ligaments, including the medial collateral ligament (MCL). The MCL provides stability to the knee and helps prevent its excessive inward movement. The MCL also has a thin layer of connective tissue known as the epiligament (EL), which adheres to the ligament. This unique feature has drawn attention in the field of ligament healing research, as it may have implications for the recovery process of MCL injuries. According to the EL theory, ligament regeneration relies heavily on the provision of cells, blood vessels, and molecules. The present study sought to compare the expression of vascular endothelial growth factor (VEGF), CD34, and α-smooth muscle actin (α-SMA) in healthy knees’ proximal and distal MCL segments to better understand how these proteins affect ligament healing. By improving the EL theory, the current results could lead to more effective treatments for ligament injury. To conduct the present analysis, monoclonal antibodies were used against CD34, α-SMA, and VEGF to examine samples from 12 fresh knee joints’ midsubstance MCLs. We identified a higher cell density in the EL than in the ligament connective tissue, with higher cell counts in the distal than in the proximal EL part. CD34 immunostaining was weak or absent in blood vessels and the EL, while α-SMA immunostaining was strongest in smooth muscle cells and the EL superficial layer. VEGF expression was mainly in the blood vessels’ tunica media. The distal part showed more SMA-positive microscopy fields and higher cell density than the proximal part (4735 vs. 2680 cells/mm<sup>2</sup>). Our study identified CD34, α-SMA, and VEGF expression in the MCL EL, highlighting their critical role in ligament healing. Differences in α-SMA expression and cell numbers between the ligament’s proximal and distal parts may explain different healing capacities, supporting the validity of the EL theory in ligament recovery. |
| first_indexed | 2024-04-24T18:31:23Z |
| format | Article |
| id | doaj.art-89d10a6e594e4460860dcc4c4d5e88f6 |
| institution | Directory Open Access Journal |
| issn | 2227-9059 |
| language | English |
| last_indexed | 2024-04-24T18:31:23Z |
| publishDate | 2024-03-01 |
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| series | Biomedicines |
| spelling | doaj.art-89d10a6e594e4460860dcc4c4d5e88f62024-03-27T13:23:03ZengMDPI AGBiomedicines2227-90592024-03-0112365910.3390/biomedicines12030659Are There Any Differences in the Healing Capacity between the Medial Collateral Ligament’s (MCL) Proximal and Distal Parts in the Human Knee? Quantitative and Immunohistochemical Analysis of CD34, α-Smooth Muscle Actin (α-SMA), and Vascular Endothelial Growth Factor (VEGF) Expression Regarding the Epiligament (EL) TheoryGeorgi P. Georgiev0Yordan Yordanov1Lyubomir Gaydarski2Richard Shane Tubbs3Łukasz Olewnik4Nicol Zielinska5Maria Piagkou6Julian Ananiev7Iva N. Dimitrova8Svetoslav A. Slavchev9Ivan Terziev10Athikhun Suwannakhan11Boycho Landzhov12Department of Orthopedics and Traumatology, University Hospital Queen Giovanna-ISUL, Medical University of Sofia, 1527 Sofia, BulgariaDepartment of Pharmacology, Pharmacotherapy and Toxicology, Faculty of Pharmacy, Medical University of Sofia, 1000 Sofia, BulgariaDepartment of Anatomy, Histology and Embryology, Medical University of Sofia, 1431 Sofia, BulgariaDepartment of Anatomical Sciences, St. George’s University, St. George 1473, GrenadaDepartment of Anatomical Dissection and Donation, Medical University of Lodz, 90-419 Lodz, PolandDepartment of Anatomical Dissection and Donation, Medical University of Lodz, 90-419 Lodz, PolandDepartment of Anatomy, School of Medicine, National and Kapodistrian University of Athens, 11527 Athens, GreeceDepartment of General and Clinical Pathology, Faculty of Medicine, Trakia University, 6000 Stara Zagora, BulgariaDepartment of Cardiology, University Hospital “St. Ekaterina”, Medical University of Sofia, 1431 Sofia, BulgariaUniversity Hospital of Orthopedics “Prof. B. Boychev”, Medical University of Sofia, 1614 Sofia, BulgariaDepartment of Pathology, University Hospital Queen Giovanna-ISUL, 1527 Sofia, BulgariaDepartment of Anatomy, Faculty of Science, Mahidol University, Bangkok 10400, ThailandDepartment of Anatomy, Histology and Embryology, Medical University of Sofia, 1431 Sofia, BulgariaThe human knee is a complex joint that comprises several ligaments, including the medial collateral ligament (MCL). The MCL provides stability to the knee and helps prevent its excessive inward movement. The MCL also has a thin layer of connective tissue known as the epiligament (EL), which adheres to the ligament. This unique feature has drawn attention in the field of ligament healing research, as it may have implications for the recovery process of MCL injuries. According to the EL theory, ligament regeneration relies heavily on the provision of cells, blood vessels, and molecules. The present study sought to compare the expression of vascular endothelial growth factor (VEGF), CD34, and α-smooth muscle actin (α-SMA) in healthy knees’ proximal and distal MCL segments to better understand how these proteins affect ligament healing. By improving the EL theory, the current results could lead to more effective treatments for ligament injury. To conduct the present analysis, monoclonal antibodies were used against CD34, α-SMA, and VEGF to examine samples from 12 fresh knee joints’ midsubstance MCLs. We identified a higher cell density in the EL than in the ligament connective tissue, with higher cell counts in the distal than in the proximal EL part. CD34 immunostaining was weak or absent in blood vessels and the EL, while α-SMA immunostaining was strongest in smooth muscle cells and the EL superficial layer. VEGF expression was mainly in the blood vessels’ tunica media. The distal part showed more SMA-positive microscopy fields and higher cell density than the proximal part (4735 vs. 2680 cells/mm<sup>2</sup>). Our study identified CD34, α-SMA, and VEGF expression in the MCL EL, highlighting their critical role in ligament healing. Differences in α-SMA expression and cell numbers between the ligament’s proximal and distal parts may explain different healing capacities, supporting the validity of the EL theory in ligament recovery.https://www.mdpi.com/2227-9059/12/3/659medial collateral ligamentepiligamenttheoryknee joint |
| spellingShingle | Georgi P. Georgiev Yordan Yordanov Lyubomir Gaydarski Richard Shane Tubbs Łukasz Olewnik Nicol Zielinska Maria Piagkou Julian Ananiev Iva N. Dimitrova Svetoslav A. Slavchev Ivan Terziev Athikhun Suwannakhan Boycho Landzhov Are There Any Differences in the Healing Capacity between the Medial Collateral Ligament’s (MCL) Proximal and Distal Parts in the Human Knee? Quantitative and Immunohistochemical Analysis of CD34, α-Smooth Muscle Actin (α-SMA), and Vascular Endothelial Growth Factor (VEGF) Expression Regarding the Epiligament (EL) Theory Biomedicines medial collateral ligament epiligament theory knee joint |
| title | Are There Any Differences in the Healing Capacity between the Medial Collateral Ligament’s (MCL) Proximal and Distal Parts in the Human Knee? Quantitative and Immunohistochemical Analysis of CD34, α-Smooth Muscle Actin (α-SMA), and Vascular Endothelial Growth Factor (VEGF) Expression Regarding the Epiligament (EL) Theory |
| title_full | Are There Any Differences in the Healing Capacity between the Medial Collateral Ligament’s (MCL) Proximal and Distal Parts in the Human Knee? Quantitative and Immunohistochemical Analysis of CD34, α-Smooth Muscle Actin (α-SMA), and Vascular Endothelial Growth Factor (VEGF) Expression Regarding the Epiligament (EL) Theory |
| title_fullStr | Are There Any Differences in the Healing Capacity between the Medial Collateral Ligament’s (MCL) Proximal and Distal Parts in the Human Knee? Quantitative and Immunohistochemical Analysis of CD34, α-Smooth Muscle Actin (α-SMA), and Vascular Endothelial Growth Factor (VEGF) Expression Regarding the Epiligament (EL) Theory |
| title_full_unstemmed | Are There Any Differences in the Healing Capacity between the Medial Collateral Ligament’s (MCL) Proximal and Distal Parts in the Human Knee? Quantitative and Immunohistochemical Analysis of CD34, α-Smooth Muscle Actin (α-SMA), and Vascular Endothelial Growth Factor (VEGF) Expression Regarding the Epiligament (EL) Theory |
| title_short | Are There Any Differences in the Healing Capacity between the Medial Collateral Ligament’s (MCL) Proximal and Distal Parts in the Human Knee? Quantitative and Immunohistochemical Analysis of CD34, α-Smooth Muscle Actin (α-SMA), and Vascular Endothelial Growth Factor (VEGF) Expression Regarding the Epiligament (EL) Theory |
| title_sort | are there any differences in the healing capacity between the medial collateral ligament s mcl proximal and distal parts in the human knee quantitative and immunohistochemical analysis of cd34 α smooth muscle actin α sma and vascular endothelial growth factor vegf expression regarding the epiligament el theory |
| topic | medial collateral ligament epiligament theory knee joint |
| url | https://www.mdpi.com/2227-9059/12/3/659 |
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