Abstract
Background: Posttraumatic osteoarthritis (PTOA) can occur after intra-articular fracture despite anatomic fracture reduction. It has been hypothesized that an early inflammatory response after intra-articular injury could lead to irreversible cartilage damage that progresses to PTOA. Therefore, in addition to meticulous fracture reduction, it would be ideal to prevent this initial inflammatory response but little is known about the composition of the synovial environment after intra-articular fracture. The purpose of this work was to characterize the inflammatory cytokine and matrix metalloproteinase (MMP) composition in the synovial fluid (SF) of patients with acute intra-articular ankle fractures. Methods: Twenty-one patients with an intra-articular ankle fracture were included in this study. All patients had a contralateral ankle joint that was pain free, had no radiographic evidence of arthritis, and no history of trauma. The uninjured ankle served as a matched control. SF was obtained from bilateral ankles at the time of surgery which occurred at a mean of 17 days post-fracture (range 8-40). The SF was analyzed for granulocyte macrophage colony-stimulating factor (GM-CSF), interferon-gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), interleukin (IL)-1β, IL-2, IL-6, IL-8, IL-10, IL-12p70, MMP-1, MMP-2, MMP-3, MMP-9, MMP-10, CTXII, sGAG, and bilirubin/biliverdin (markers of hemearthrosis) using either multiplex assay or ELISA using commercially available kits. Mean concentrations of each factor were compared between SF from fractured and control ankles, and correlation analysis was done to determine potential relationships between levels of cytokines and time from fracture and age at fracture. Results: Twelve of 18 measured factors including GM-CSF, IL-10, IL-1β, IL-6, IL-8, TNF-α, MMP-1, MMP-2, MMP-3, MMP-9, MMP-10, and bilirubin/biliverdin were found to be significantly higher in the fractured ankles. Mean concentrations of ECM degradation markers (sGAG and CTXII) were not found to be significatnly different between groups. Conclusion: These data indicate that after intra-articular ankle fracture the SF exhibits a largely pro-inflammatory and extra-cellular matrix degrading environment similar to that described in idiopathic osteoarthritis. IL-6, IL-8, MMP-1, MMP-2, MMP-3, MMP-9, and MMP-10 were significantly elevated and may play a role in the development of PTOA. Clinical Relevance: In addition to anatomic fracture reduction, these data lend credence to reducing acute intra-articular inflammation through the development of antagonists to these pro-inflammatory and degrading mediators. Likewise, intra-articular lavage might reduce this inflammatory burden.
| Original language | English |
|---|---|
| Pages (from-to) | 1264-1271 |
| Number of pages | 8 |
| Journal | Foot and Ankle International |
| Volume | 36 |
| Issue number | 11 |
| DOIs | |
| State | Published - Nov 1 2015 |
Keywords
- ankle fracture
- arthritis
- interleukin
- intra-articular
- joint injury
- matrix metalloproteinase
- osteoarthritis
- posttraumatic
- synovial fluid
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In: Foot and Ankle International, Vol. 36, No. 11, 01.11.2015, p. 1264-1271.
Research output: Contribution to journal › Article › peer-review
TY - JOUR
T1 - Inflammatory cytokines and matrix metalloproteinases in the synovial fluid after intra-articular ankle fracture
AU - Adams, Samuel B.
AU - Setton, Lori A.
AU - Bell, Richard D.
AU - Easley, Mark E.
AU - Huebner, Janet L.
AU - Stabler, Thomas
AU - Kraus, Virginia B.
AU - Leimer, Elizabeth M.
AU - Olson, Steven A.
AU - Nettles, Dana L.
N1 - Funding Information: An important step toward successful diagnosis and management of PTOA in the ankle is to reveal factors that contribute to pathology progression. In this study, we aspirated SF from 21 fractured ankles and patient-matched contralateral healthy ankles within 40 days of fracture and measured the concentrations of 15 cytokines and MMPs, 2 markers of ECM degradation, and bilirubin and biliverdin (markers of heme metabolism). We believe this represents the first study to characterize ankle SF during the acute phase postfracture with patient-matched SF data as a control. We found that concentrations of 12 cytokines and MMPs were significantly elevated in the fractured ankles compared to the healthy ankles, several of which are known to play a role in joint trauma and OA, including IL-1β, TNF-α, IL-6, IL-8, and the MMPs. 4 , 11 , 16 , 19 In addition, cytokine concentrations for the fractured ankles were in the range prevously reported for the injured knee. 4 , 6 , 19 , 33 IL-1β and TNF-α have been shown to be acutely elevated in serum and synovial fluid following ACL injury with or without intra-articular fracture in the knee 4 , 6 , 19 , 29 , 33 and to be associated with higher expression of IL-6, IL-8, MMP-1, and MMP-3 (reviewed in 38 ), all of which were elevated in the SF from fractured ankles in this study. In addition to upregulation of these cytokines, IL-1β and TNF-α also act to suppress synthesis of ECM components, including proteoglycan and type II collagen. Studies involving ACL tears in the knee report an initial elevation in IL-1β and/or TNF-α following trauma with a return to baseline levels within 1 to 2 weeks. 4 , 19 In the ankle, information on the inflammatory milieu within the injured joint is less studied. Consistent with our findings, Furman and co-workers recently reported a significant elevation of both IL-1β and TNF-α following intra-aticular ankle fracture compared to OA knee SF, with no correlation with time from injury (n=6, time from injury range = 5-21 days). 12 However, anti-IL-1β, but not anti-TNF-α, therapy has been shown in a mouse model of intra-articular fracture to decrease arthritic changes when given locally during the acute inflammatory phase, 13 suggesting the potential for longer persistence of IL-1β in the ankle following fracture. MMPs are enzymes that break down collagen either through acting directly on the fibrillar forms (MMP-1 and MMP-3) or by acting on the gelatinous (partially hydrolyzed) forms in the case of MMP-2 and MMP-9. All measured MMPs, including MMP-10 (which contributes to the catabolism of proteoglycan and fibronectin) were significantly higher in SF from fractured ankles. This is consistent with studies showing elevated MMP-1 and MMP-3 in culture media and cartilage tissue following injury, 7 and in the synovium of knee joints following ACL injury. 17 Interestingly, one study detailing the expression of MMPs in healthy and OA hip cartilage found increased expression of MMP-2 and MMP-9 in OA cartilage, but decreased expression of MMP-1, MMP-3, and MMP-10 compared to healthy cartilage. 21 The present data, together with published reports, suggest a potential longer-term role for MMP-2 and MMP-9 in the development of PTOA. However, despite the upregulation of these MMPs, no significant difference was found between healthy and fractured ankles for markers of collagen (CTXII) or proteoglycan (sGAG) catabolism, perhaps owing to the timing of collection, after the bulk of sGAG release and before a detectable increase in CTXII. Significantly higher concentrations of IL-6 and IL-8 were also noted in SF from fractured ankles. IL-6 has both pro- and anti-inflammatory effects 20 , 38 and has been shown to be a powerful serum biomarker of trauma, stress, and pain that is positively correlated with severity of injury. 3 , 14 IL-6 has also been shown to play a major role in OA and affects the joint much in the same way as other cytokines, that is, decreasing matrix production and upregulating matrix catabolism. 38 IL-8 is induced by both IL-1β and TNF-α and is a potent chemokine for neutrophils 27 as well as neutrophil-mediated cartilage catabolism. 9 Consistent with our data, recent studies in the knee have also shown an increase in both IL-6 and IL-8 in SF from patients with acute knee injury and hemarthrosis 34 and ACL injury, 4 , 19 with a negative relationship with time from injury. Likewise, IL-8, but not IL-6, was recently shown to decrease with time from injury in postfracture ankle SF. 12 Interestingly, one study also showed a correlation of IL-6 and IL-8 with osteonectin expression in SF following knee injury. 33 Osteonectin has been shown to be expressed in early OA cartilage and has been implicated in cartilage calcification. 28 Taken together, these data point to a role for IL-6 and IL-8 in the acute phase of joint injury, and warrant the investigation of their role in PTOA. Consistent with the results of Furman and coworkers, 12 IL-10, a potent anti-inflammatory cytokine, was also elevated in the SF of fractured ankles in our study. IL-10 has been shown to stimulate type II collagen and aggrecan production, inhibit MMPs and chondrocyte apopotosis, and downregulate IL-1β and TNF-α, by stimulating production of IL-1Ra and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1). 38 The presence of IL-10 in the fractured ankle SF suggests that a potent chondroprotective mechanism is also stimulated along with the pro-inflammatory milieu following acute ankle fracture. Yet, it is seemingly outnumbered. Interestingly, IL-10 was negatively correlated with time from fracture, suggesting its importance during the early acute phase. Understanding the balance between destructive and protective cytokines and how and when this balance is tipped toward progressive disease will be key in diagnosing and treating PTOA in the ankle. Levels for GM-CSF and heme products were found to be significantly elevated in the fracture group as well, but it is difficult to draw conclusions owing to the high percentage of samples for which neither was detected in either group ( Table 1 ). However, it is noteworthy that micromolar concentrations of bilirubin have been shown to inhibit cartilage growth in vitro. 37 No significant difference was detected between groups for IFN-γ, IL-12p70, or IL-2, all of which were found to be absent in most samples. There are several limitions to this study. First, one patient did not have SF aspiration until 40 days after fracture. Although this may be considered a time point out of the acute phase, the acute phase has not been defined. One study defined an average of 21 years from ankle fracture to the development of end-stage PTOA, 18 and therefore 40 days is still early in the development of PTOA. Including this time point did allow for better confidence in our time correlations. Second, not all of the ankle fractures underwent concomitant arthroscopy to determine cartilage damage, although aside from a frank OLT, the extent of cartilage damage is not necessarily identified by direct visualization but these injuries should be recorded in future studies. However, our data demonstrate no difference in widespread cartilage damage between the fracture and control groups. Finally, inflammation is considered the first step of healing and, therefore, it may be that acute inflammation after injury is part of the natural healing process and should not be interfered with. Although this may be true, the inflammatory response after fracture is intended for the healing bone. However, in an intra-articular fracture, the entire joint including cartilage and synovium not near the fracture are secondarily subjected to the inflammatory response intended for bone healing, as demonstrated in this study. Cartilage and synovium exposure to these cytokines, MMPs, and bilirubin, as previously described, has been demonstrated to be detrimental to these tissues. In conclusion, this study represents a first step in characterizing the posttraumatic intra-articular environment in the ankle with comparison to patient-matched healthy controls. In order to fully understand how persistence of inflammation may contribute to the development or abatement of PTOA, a larger, long-term longitudinal study will need to be undertaken. Despite this limitation, this study is the first of its kind in the ankle to compare the intra-articular environment in the fractured ankle to a patient’s own uninjured contralateral joint. Because a high percentage of fractured ankles go on to develop PTOA, it is imperative to understand how the forces at play in the acute phase of injury affect PTOA progression in order to develop targeted therapies capable of reducing the risk of PTOA or slowing its progression. Moreover, until therapies are developed, these data support consideration of early intra-articular lavage or intraoperative lavage, either through the fracture or via ankle arthroscopy, to reduce the intra-articular inflammatory burden and exposure of the cartilage and synovium to these detrimental factors. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. Funding The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: U.S. Department of Health and Human Services, National Institutes of Health, R01AR047422 (LAS). Publisher Copyright: © 2015 American Orthopaedic Foot & Ankle Society.
PY - 2015/11/1
Y1 - 2015/11/1
N2 - Background: Posttraumatic osteoarthritis (PTOA) can occur after intra-articular fracture despite anatomic fracture reduction. It has been hypothesized that an early inflammatory response after intra-articular injury could lead to irreversible cartilage damage that progresses to PTOA. Therefore, in addition to meticulous fracture reduction, it would be ideal to prevent this initial inflammatory response but little is known about the composition of the synovial environment after intra-articular fracture. The purpose of this work was to characterize the inflammatory cytokine and matrix metalloproteinase (MMP) composition in the synovial fluid (SF) of patients with acute intra-articular ankle fractures. Methods: Twenty-one patients with an intra-articular ankle fracture were included in this study. All patients had a contralateral ankle joint that was pain free, had no radiographic evidence of arthritis, and no history of trauma. The uninjured ankle served as a matched control. SF was obtained from bilateral ankles at the time of surgery which occurred at a mean of 17 days post-fracture (range 8-40). The SF was analyzed for granulocyte macrophage colony-stimulating factor (GM-CSF), interferon-gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), interleukin (IL)-1β, IL-2, IL-6, IL-8, IL-10, IL-12p70, MMP-1, MMP-2, MMP-3, MMP-9, MMP-10, CTXII, sGAG, and bilirubin/biliverdin (markers of hemearthrosis) using either multiplex assay or ELISA using commercially available kits. Mean concentrations of each factor were compared between SF from fractured and control ankles, and correlation analysis was done to determine potential relationships between levels of cytokines and time from fracture and age at fracture. Results: Twelve of 18 measured factors including GM-CSF, IL-10, IL-1β, IL-6, IL-8, TNF-α, MMP-1, MMP-2, MMP-3, MMP-9, MMP-10, and bilirubin/biliverdin were found to be significantly higher in the fractured ankles. Mean concentrations of ECM degradation markers (sGAG and CTXII) were not found to be significatnly different between groups. Conclusion: These data indicate that after intra-articular ankle fracture the SF exhibits a largely pro-inflammatory and extra-cellular matrix degrading environment similar to that described in idiopathic osteoarthritis. IL-6, IL-8, MMP-1, MMP-2, MMP-3, MMP-9, and MMP-10 were significantly elevated and may play a role in the development of PTOA. Clinical Relevance: In addition to anatomic fracture reduction, these data lend credence to reducing acute intra-articular inflammation through the development of antagonists to these pro-inflammatory and degrading mediators. Likewise, intra-articular lavage might reduce this inflammatory burden.
AB - Background: Posttraumatic osteoarthritis (PTOA) can occur after intra-articular fracture despite anatomic fracture reduction. It has been hypothesized that an early inflammatory response after intra-articular injury could lead to irreversible cartilage damage that progresses to PTOA. Therefore, in addition to meticulous fracture reduction, it would be ideal to prevent this initial inflammatory response but little is known about the composition of the synovial environment after intra-articular fracture. The purpose of this work was to characterize the inflammatory cytokine and matrix metalloproteinase (MMP) composition in the synovial fluid (SF) of patients with acute intra-articular ankle fractures. Methods: Twenty-one patients with an intra-articular ankle fracture were included in this study. All patients had a contralateral ankle joint that was pain free, had no radiographic evidence of arthritis, and no history of trauma. The uninjured ankle served as a matched control. SF was obtained from bilateral ankles at the time of surgery which occurred at a mean of 17 days post-fracture (range 8-40). The SF was analyzed for granulocyte macrophage colony-stimulating factor (GM-CSF), interferon-gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), interleukin (IL)-1β, IL-2, IL-6, IL-8, IL-10, IL-12p70, MMP-1, MMP-2, MMP-3, MMP-9, MMP-10, CTXII, sGAG, and bilirubin/biliverdin (markers of hemearthrosis) using either multiplex assay or ELISA using commercially available kits. Mean concentrations of each factor were compared between SF from fractured and control ankles, and correlation analysis was done to determine potential relationships between levels of cytokines and time from fracture and age at fracture. Results: Twelve of 18 measured factors including GM-CSF, IL-10, IL-1β, IL-6, IL-8, TNF-α, MMP-1, MMP-2, MMP-3, MMP-9, MMP-10, and bilirubin/biliverdin were found to be significantly higher in the fractured ankles. Mean concentrations of ECM degradation markers (sGAG and CTXII) were not found to be significatnly different between groups. Conclusion: These data indicate that after intra-articular ankle fracture the SF exhibits a largely pro-inflammatory and extra-cellular matrix degrading environment similar to that described in idiopathic osteoarthritis. IL-6, IL-8, MMP-1, MMP-2, MMP-3, MMP-9, and MMP-10 were significantly elevated and may play a role in the development of PTOA. Clinical Relevance: In addition to anatomic fracture reduction, these data lend credence to reducing acute intra-articular inflammation through the development of antagonists to these pro-inflammatory and degrading mediators. Likewise, intra-articular lavage might reduce this inflammatory burden.
KW - ankle fracture
KW - arthritis
KW - interleukin
KW - intra-articular
KW - joint injury
KW - matrix metalloproteinase
KW - osteoarthritis
KW - posttraumatic
KW - synovial fluid
UR - https://www.scopus.com/pages/publications/84946043884
U2 - 10.1177/1071100715611176
DO - 10.1177/1071100715611176
M3 - Article
C2 - 26449389
AN - SCOPUS:84946043884
SN - 1071-1007
VL - 36
SP - 1264
EP - 1271
JO - Foot and Ankle International
JF - Foot and Ankle International
IS - 11
ER -