Mussel Adhesive Protein as a Promising Alternative to Fibrin for Scaffold Fixation during Cartilage Repair Surgery.

OBJECTIVE: Fibrin has been used as a standard material for scaffold fixation during cartilage repair surgery. Most of the commercially available fibrin preparations need an additional method for scaffold fixation, most often with sutures, thus damaging the surrounding healthy cartilage. There is therefore a need to find alternatives to this method. In our study, we have investigated the potential possibility to use mussel adhesive protein as such an alternative. METHODS: In this study, hydrophobic plastic was coated with the mussel adhesive protein Mefp-1 as well as with other cell adhesives (poly-lysine, fibronectin, and collagen). Human keratinocytes and chondrocytes were seeded on these substrates at 37°C in culture medium, followed by analysis of attachment and proliferation by crystal violet staining and metabolic labelling. Performance of Mefp-1 and fibrin as tissue glues were estimated by tensional force resistance measurement of moist porcine dermis (as a correlate to scaffold) glued to dermis, cartilage, or bone at 37°C. RESULTS: Mefp-1 supported maximal cell attachment at a coating density of approximately 1 µg/cm2. This was at least as good as the other adhesives tested. In addition, it supported cell proliferation at least as good as regular tissue culture plastic over a 7-day period. Measurement of tensional force resistance showed that Mefp-1 performed equally well as fibrin when porcine dermis was glued to cartilage and bone at the same concentration. Separation of the moist tissues after 15-minute incubation required a force of approximately 1 N/cm2 for both compounds. CONCLUSIONS: Mefp-1 show properties that qualify it as a compound that potentially could replace fibrin as a tissue glue for scaffold fixation. Given the possibilities to modify this protein by bioengineering, it is likely that the properties can be further improved.

No outgrowth of chondrocytes from non-digested particulated articular cartilage embedded in commercially available fibrin matrix: an in vitro study.

BACKGROUND: Commercially available fibrin is routinely being used as both a matrix in certain cartilage repair techniques and a method for scaffold fixation. Chondrocytes from non-digested particulated cartilage fragments are proposed as a possible source for new cartilage tissue formation in some operative techniques. The goal of this study was to test that chondrocytes from particulated articular cartilage embedded in fibrin have an active role in the process of cartilage repair, as well as if commercially available fibrin should be used as a suitable matrix. METHODS: Articular cartilage was obtained from patients undergoing total knee replacement surgery. The biopsies were particulated in small, 1-2-mm(3) pieces and embedded in fibrin. Two groups were compared in our study, particulated articular cartilage with and without collagenase treatment. The specimens were analyzed by optical microscopy after 2-5 weeks of cultivation in a special construct embedded in a cell culture medium containing particulated cartilage embedded in fibrin in the upper phase and cancellous bone in the lower phase under the perforated nylon membrane. RESULTS: None of the biopsies taken from four different patients showed the outgrowth of chondrocytes or bone marrow-originated cells into the fibrin matrix in our experimental model. CONCLUSIONS: It has been shown in our experimental model in vitro little to support the theory that articular chondrocytes from particulated articular cartilage embedded in fibrin have an active role in cartilage repair in its early stage.

Periosteal Transplantation Combined with the Autologous Matrix-Induced Chondrogenesis (AMIC) Technique in Isolated Patellofemoral Osteoarthritis: A Case Report.

OBJECTIVE: Isolated cases of osteoarthritis of the knee represent a major clinical problem. A particular challenge is a case in which both articular surfaces are affected. Such is the case with the isolated form of patellofemoral osteoarthritis. Studies that describe methods for treating such conditions are few, and the results are not too promising. METHODS: In this article, we present one such case of isolated patellofemoral osteoarthritis in which we used a new approach combining periosteal transplantation on one side and the autologous matrix-induced chondrogenesis (AMIC) technique on the other side. RESULTS: The patient has improved, measured by the Knee injury and Osteoarthritis Outcome Score (KOOS) from 48 preoperatively to 77 at 1 year postoperatively (mean improvement) and measured by the Lysholm score from 45 preoperatively to 90 at 1 year postoperatively. CONCLUSION: This original approach has shown promising results in this patient and could be tested in a larger group of patients with the same type of osteoarthritis in order to estimate its real clinical value.

Articular cartilage surgery in outpatients: a pilot study.

Open knee surgery for the treatment of large symptomatic cartilage defects is routinely performed in the inpatient stay, where the patients are hospitalized for several days after surgery. This has implications for both costs for the health system and medical complications such as hospital-related infections. In this article, we describe for the first time that this type of operation can be performed as outpatient surgery without any complications for the patients and with good clinical results that in our sample do not differ from those reported in larger groups of patients who underwent surgery and were hospitalized thereafter.

Beta-endorphin regulation of MAPKs in cultured human articular chondrocytes: MAPK inhibitors prevent the increase of IL-1 beta protein levels during beta-endorphin stimulation.

We investigated the effect of beta-endorphin on the activities of mitogen-activated protein kinases in cultured human articular chondrocytes in order to elucidate its effect on cartilage. Monolayer cultures of chondrocytes obtained from patients undergoing total knee arthroplasty were treated with 60, 600, or 6000 ng/ml beta-endorphin, or 100 ng/ml naltrexone combined with 600 ng/ml beta-endorphin. The regulation of three major mitogen-activated protein kinases phosphorylation, ERKp44/p42, p38, and JNK, was determined by Western blotting. We also examined the influence of specific mitogen-activated protein kinase inhibitors on IL-1 beta protein levels during beta-endorphin stimulation. The results demonstrate that beta-endorphin, dependent on concentration and duration of stimulation, significantly affected the activation of the three mitogen-activated protein kinases in cultured human articular chondrocytes. Naltrexone in some cases significantly regulated the mitogen-activated protein kinases in different ways when added to beta-endorphin 600 ng/ml. Furthermore, specific mitogen-activated protein kinase inhibitors hindered the increase of IL-1 beta during beta-endorphin incubation. The effect of beta-endorphin seen in this study is considered critical for the production of several mediators of cartilage damage in an arthritic joint.

Detection of mRNA transcripts of truncated opiate precursor (POMC) in human cartilage.

In the present study, we have investigated the presence of pro-opiomelanocortin C-terminal fragment derived-peptides in human articular cartilage and cultured chondrocytes. beta-Lipotropin and beta-endorphin were monitored in different cell cultures and biopsies using different techniques. Biopsies were taken from patients undergoing total knee arthroplasty due to osteoarthritis. Both fresh tissue sections and chondrocytes cultured in monolayer were used in the study. Immunohistochemistry, immunocytochemistry, reverse transcriptase-polymerase chain reaction and qualitative Western blots were carried out. The results of the reverse transcriptase-polymerase chain reaction showed transcription of a truncated-form of mRNA for pro-opiomelanocortin in native cartilage and cultured chondrocytes. There was no detection of endogenous production of beta-lipotropin or beta-endorphin in human articular chondrocytes, either in situ or in vitro. Whether pro-opiomelanocortin-derived peptides of non-cartilaginous origin are present in articular cartilage itself still remains unclear.

Opiate regulation of IL-1beta and TNF-alpha in cultured human articular chondrocytes.

In order to investigate if beta-endorphins anti-inflammatory effect in cartilage-damaging states is mediated via tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta), we examined its influence on these two cytokines in vitro. Human articular chondrocytes were obtained from patients undergoing total knee arthroplasty and stimulated with beta-endorphin (60-6000 ng/ml). Protein levels of TNF-alpha and IL-1 beta were measured by ELISA in supernatants from articular chondrocyte cultures. beta-Endorphin significantly increased the levels of IL-1 beta for all concentrations used after 15 min incubation, and when stimulated with 600 and 6000 ng/ml after 24 h incubation. The opioid-induced increase in IL-1 beta was blocked by naltrexone in the group tested. TNF-alpha expression was also significantly stimulated by 60 and 600 ng/ml beta-endorphin after 15 min, an effect blocked by naltrexone in the group tested. These findings indicate that the mechanism of beta-endorphins anti-inflammatory influence in cartilage-damaging states is not apparently mediated via these two cytokines modulation.

Expression of functional mu-opioid receptors in human osteoarthritic cartilage and chondrocytes.

There is evidence of effects of morphine on cell proliferation and intraarticular morphine produces analgesia and has an anti-inflammatory effect in chronic arthritis. The effects of opioids are mediated through the G-protein-coupled receptors affecting the cAMP pathway. We demonstrated that human osteoarthritic cartilage and cultured chondrocytes possess the mu-opioid receptor. The presence of the receptor was shown by immunodetection, polymerase chain reaction, and Western blotting. Stimulation of chondrocytes with beta-endorphin resulted in decreased phosphorylation of the transcription factor cAMP responsive element binding protein (CREB). The effect was reversed by naltrexone. The obtained results indicate that in human articular chondrocytes opioids affect, via the mu-opioid receptor, the transcription factor CREB which in turn can cause subsequent changes in gene expression.