Preservation Of Articular Cartilage Research Articles

Acromegalic arthropathy: current perspectives

Acromegaly is associated with manifestations in many organs including the heart, colon, skin, bone, and many joints. Both weight and non-weight bearing joints are affected including shoulders, wrists, knees, hips, and the spine [1–3]. Patients with long-term cure or long-term biochemical control of acromegaly still suffer from acromegalic arthropathy. The prevalence of clinical and radiological osteoarthritis of the hip, hand, and knee reaches even up to 80 % [1]. In comparison with primary osteoarthritis, secondary osteoarthritis in patients with long-term cured acromegaly is characterized predominantly by osteophytes, which were observed frequently without joint space narrowing indicating preservation of articular cartilage. Patients with acromegaly report less functional disability of the hips and knees than the patients with primary generalized osteoarthritis [1]. Radiological features of acromegalic arthropathy progress despite long-term biochemical remission of acromegaly. In contrast to the crosssectional observations, which indicate widened joint spaces in patients cured or controlled from acromegaly, prolongation of follow-up is characterized by a decrease in joint space widening and progression of osteophytosis, despite long-term biochemical control. Thus, this arthropathy appears to be a progressive joint disease that is not merely halted or reversed by control of acromegaly [4]. Remarkably, medically well-controlled patients show more radiographic progression compared with surgically cured patients. In previous studies, GH secretion was still slightly abnormal during treatment with SMS analogs, despite appropriate biochemical control according to current criteria [5]. However, persistent abnormal GH secretion despite somatostatin analogs is not a straight forward explanation, since active acromegaly is associated with joint space widening, rather than with joint space narrowing. Alternatively, it may be hypothesized that SMS analogs have a direct effect on the cartilage of joints. Therefore, it may be possible that SMS analogs contribute to the pathophysiology of the progression of acromegalic arthropathy. In addition to arthropathy, patients with active and cured/controlled acromegaly suffer from an increased prevalence of vertebral fractures, although these patients are considered to have a low risk of osteoporosis since bone mineral density is not decreased [6]. More than 50 % of these patients suffered from vertebral fractures. There was no association with the duration of disease control, bone mineral density, markers of bone turnover, or acromegalic disease characteristics. There was a striking number of fractures per patient (mean 3.4 ± 0.3, range 1–8) [7]. It should be realized that the most of these fractures were asymptomatic. Fractures were also evident in men, especially in the presence of hypogonadism. In view of the significant morbidity associated with vertical fractures, the inclusion of lateral conventional radiographs of the thoracic and lumbar spine has been proposed in the screening of all patients with acromegaly both at diagnosis and during follow-up after establishment of disease control. Longitudinal studies are required to assess both the contribution of risk factors for these fractures including vitamin D, (replacement for) hypopituitarism, and of glucocorticoid replacement at a low dose and the optimal treatment modalities to prevent (additional) vertebral fractures. J. A. Romijn (&) Department of Medicine, Academic Medical Center, University of Amsterdam, P.O. Box 22660, 1100 DD Amsterdam, The Netherlands e-mail: j.a.romijn@amc.uva.nl

Vitreous preservation of articular cartilage from cryoinjury in rabbits

Frozen osteoarticular grafts treated with liquid nitrogen are utilized for joint reconstruction after tumor resection, but the joints may subsequently develop osteoarthritic changes. To preserve articular cartilage from cryoinjury, we modified a vitrification method utilized for embryo cryopreservation and demonstrated in vitro that our vitrification protocol was effective for protecting cartilage from cryoinjury. In this study, we investigated in vivo whether this vitrification method could protect against osteoarthritic changes in articular cartilage. Osteochondral plugs were obtained from the distal femur of rabbits. These grafts were divided into 3 groups: Fresh group (F-group), non-vitrification group (N-group), and vitrification group (V-group). After treatment, the plugs were re-implanted as autografts. Histological findings, chondrocyte viability, and ultrastructural examinations were examined 6, 12, and 24weeks after implantation. Histological findings of chondrocytes for the V-group showed no significant difference from those of the F-group at any time point except at 24weeks postimplantation at the non-weight bearing site (p<0.05). Viability of chondrocyte showed no significant difference from those of the F-group except at 12weeks postimplantation at the bearing site (p<0.05). In contrast, viable cells disappeared from the N-group and histology and viability significantly differed between the N-group and the V-group. Transmission electron microscopy demonstrated preservation of chondrocyte structure in the V-group and the F-group, but chondrocytes of the N-group were abnormally electron dense. Our vitrification method was effective in protecting chondrocytes from cryoinjury that might lead to cartilage degeneration. Reconstructing joints with osteoarticular grafts containing living cartilage may help to avert osteoarthritic changes. Our vitrification method could prove useful for reconstruction with frozen tumor-containing autografts and for long-term storage of living cartilage for allografts.

Permeation of dimethyl sulfoxide into articular cartilage at subzero temperatures

Osteochondral allografting has been proved to be a useful method to treat diseased or damaged areas of joint surfaces. Operational long-term stocks of grafts which supply a buffer between procurement and utilization would contribute to the commercialization or industrialization of this technology. Vitrification has been thought to be a promising method for successful preservation of articular cartilage (AC), but high concentration cryoprotectants (CPAs) are used which may cause high cellular toxicity. An effective way to reduce CPA toxicity is to increase CPA concentration gradually while the temperature is lowered. Understanding the mechanism of CPA permeation at subzero temperatures is important for designing the cryopreservation protocol. In this research, the permeation of dimethyl sulfoxide (Me(2)SO) in ovine AC at subzero temperatures was studied experimentally. Pretreated AC discs were exposed in Me(2)SO solutions for different time (0, 5, 15, 30, 50, 80, and 120 min) at three temperature levels (-10, -20, and -30 °C). The Me(2)SO concentration within the tissue was determined by ultraviolet (UV) spectrophotometry. The diffusion coefficients were estimated to be 0.85×10(-6), 0.48×10(-6), and 0.27×10(-6) cm(2)/s at -10, -20, and -30 °C, respectively, and the corresponding activation energy was 29.23 kJ/mol. Numerical simulation was performed to compare two Me(2)SO addition protocols, and the results demonstrated that the total loading duration could be effectively reduced with the knowledge of permeation kinetics.

Articular Cartilage Changes in Patients With Osteoarthritis After Osteotomy

Background: High tibial osteotomy (HTO) is a method used to treat medial compartmental osteoarthritis in the knee. The realignment of the knee changes the loading patterns within the joint and may allow for regeneration of articular cartilage. Magnetic resonance imaging methods can be used to assess the quality of the regenerated cartilage. Hypothesis: Altering mechanical alignment through HTO will have predictable effects on articular cartilage, allowing cartilage preservation and possible regeneration. Quality of regenerated cartilage will be inferior to normal articular cartilage. Study Design: Case series; Level of evidence, 4. Methods: Ten patients undergoing medial opening wedge HTO were evaluated using dGEMRIC methods (ie, delayed gadolinium-enhanced magnetic resonance imaging of cartilage) preoperatively and at 6 months, 1 year, and 2 years after HTO. Magnetic resonance images were evaluated by hand segmentation, and T1Gd relaxation times reflective of glycosaminoglycan content were determined for these regions of interest using magnetic resonance imaging analysis software. Results: The lateral compartment displayed higher T1Gd values than the medial compartment at baseline. Initially, a decrease in T1Gd values on the medial side were observed for all patients at 6 months and remained reduced for all but 2 participants at 1 year and 2 years after HTO. However, on the medial side after 6 months, the rate of change for T1Gd values shifted from being negative (−9.6 milliseconds per month) to being positive (1.7 milliseconds per month). A positive change in the T1Gd of the medial tibial plateau was responsible for the positive overall change in the medial compartment. There was no significant difference in the rate of change on the lateral side (P = .141), with the average over the 2-year period being a decrease of 2.28 milliseconds per month. Conclusion: Medial opening wedge HTO provides subjective improvements in pain and quality of life, but the potential benefit of allowing articular cartilage preservation and possible regeneration is not well established. Results showed that after a nonweightbearing period, the rate of change in the medial compartment changes from negative to positive, indicating the potential for articular cartilage recovery secondary to an improved mechanical environment.

The Basic Science of Articular Cartilage: Structure, Composition, and Function

Articular cartilage is the highly specialized connective tissue of diarthrodial joints. Its principal function is to provide a smooth, lubricated surface for articulation and to facilitate the transmission of loads with a low frictional coefficient (Figure 1). Articular cartilage is devoid of blood vessels, lymphatics, and nerves and is subject to a harsh biomechanical environment. Most important, articular cartilage has a limited capacity for intrinsic healing and repair. In this regard, the preservation and health of articular cartilage are paramount to joint health. Figure 1. Gross photograph of healthy articular cartilage in an adult human knee. Injury to articular cartilage is recognized as a cause of significant musculoskeletal morbidity. The unique and complex structure of articular cartilage makes treatment and repair or restoration of the defects challenging for the patient, the surgeon, and the physical therapist. The preservation of articular cartilage is highly dependent on maintaining its organized architecture.

Beneficial Storage Effects of Epigallocatechin-3-O-Gallate on the Articular Cartilage of Rabbit Osteochondral Allografts

A fresh osteochondral allograft is one of the most effective treatments for cartilage defects of the knee. Despite the clinical success, fresh osteochondral allografts have great limitations in relation to the short storage time that cartilage tissues can be well-preserved. Fresh osteochondral grafts are generally stored in culture medium at 4 degrees C. While the viability of articular cartilage stored in culture medium is significantly diminished within 1 week, appropriate serology testing to minimize the chances for the disease transmission requires a minimum of 2 weeks. (-)-Epigallocatechin-3-O-gallate (EGCG) has differential effects on the proliferation of cancer and normal cells, thus a cytotoxic effect on various cancer cells, but a cytopreservative effect on normal cells. Therefore, a storage solution containing EGCG might extend the storage duration of articular cartilages. Rabbit osteochondral allografts were performed with osteochondral grafts stored at 4 degrees C in culture medium containing EGCG for 2 weeks and then the clinical effects were examined with macroscopic and histological assessment after 4 weeks. The cartilaginous structure of an osteochondral graft stored with EGCG was well-preserved with high cell viability and glycosaminoglycan (GAG) content of the extracellular matrix (ECM). After an osteochondral allograft, the implanted osteochondral grafts stored with EGCG also provided a significantly better retention of the articular cartilage with viability and metabolic activity. These data suggest that EGCG can be an effective storage agent that allows long-term preservation of articular cartilage under cold storage conditions.

Cartilage in normal and osteoarthritis conditions

The preservation of articular cartilage depends on keeping the cartilage architecture intact. Cartilage strength and function depend on both the properties of the tissue and on their structural parameters. The main structural macromolecules are collagen and proteoglycans (aggrecan). During life, cartilage matrix turnover is mediated by a multitude of complex autocrine and paracrine anabolic and catabolic factors. These act on the chondrocytes and can lead to repair, remodeling or catabolic processes like those that occur in osteoarthritis. Osteoarthritis is characterized by degradation and loss of articular cartilage, subchondral bone remodeling, and, at the clinical stage of the disease, inflammation of the synovial membrane. The alterations in osteoarthritic cartilage are numerous and involve morphologic and metabolic changes in chondrocytes, as well as biochemical and structural alterations in the extracellular matrix macromolecules.

Primary Osteoarthritis of the Elbow: Current Treatment Options

In the elbow, as in other joints, primary osteoarthritis is characterized by pain, stiffness, mechanical symptoms, and weakness. But primary osteoarthritis of the elbow is unique in that there is relative preservation of articular cartilage and maintenance of joint space, with hypertrophic osteophyte formation and capsular contracture. Medical treatment and physical therapy may be initiated in the early stages of the disease process. Surgical treatment options include arthroscopic osteocapsular débridement, open ulnohumeral arthroplasty, distraction interposition arthroplasty, and total elbow arthroplasty. The potential for instability and loosening following total elbow arthroplasty in the setting of primary osteoarthritis limits the clinical application of this procedure. This patient population is generally younger than that recommended for total elbow arthroplasty, and their higher functional demands have limited the long-term success of this treatment option. The improvement in arthroscopic débridement techniques is perhaps the greatest advancement in the treatment of osteoarthritis of the elbow in recent years.

Current Meniscal Allograft Transplantation

Meniscal allograft transplantation is now gradually transforming from an interesting alternative in meniscal restoration algorithms to a reliable treatment of unicompartmental knee pain after meniscectomy. The past decade has allowed refinements in sizing, preservation, and fixation of the meniscal allograft. Current techniques focus on adherence to biomechanical principles in attempting to duplicate the force transfer of an intact meniscal tibial plateau construct. Although intermediate term outcome results are promising in regards to pain relief, the long term objective of articular cartilage preservation remains a goal.

Treatment of experimental equine osteoarthritis by in vivo delivery of the equine interleukin-1 receptor antagonist gene.

Osteoarthritis in horses and in humans is a significant social and economic problem and continued research and improvements in therapy are needed. Because horses have naturally occurring osteoarthritis, which is similar to that of humans, the horse was chosen as a species with which to investigate gene transfer as a potential therapeutic modality for the clinical treatment of osteoarthritis. Using an established model of equine osteoarthritis that mimics clinical osteoarthritis, the therapeutic effects resulting from intra-articular overexpression of the equine interleukin-1 receptor antagonist gene through adenoviral-mediated gene transfer were investigated. In vivo delivery of the equine IL-IRa gene led to elevated intra-articular expression of interleukin-1 receptor antagonist for approximately 28 days, resulting in significant improvement in clinical parameters of pain and disease activity, preservation of articular cartilage, and beneficial effects on the histologic parameters of synovial membrane and articular cartilage. Based on these findings, gene transfer of interleukin-1 receptor antagonist is an attractive treatment modality for the equine patient and also offers future promise for human patients with osteoarthritis.

The long-term effects of hyaluronan during development of osteoarthritis following partial meniscectomy in a rabbit model

Objective The long-term effect of hyaluronan (HA) on meniscus remodeling and articular cartilage preservation was assessed during the development of osteoarthritis following partial meniscectomy in a rabbit model.Design Approximately 60% of the region of each medial meniscus of 20 rabbit knees was excised bilaterally. The left knee joint was treated with five weekly intraarticular injections of 0.3ml of HA, beginning 1 week after surgery. The right control knee was injected with PBS on the same schedule. Six months after surgery, animals were killed and the medial menisci and tibial articular cartilage were evaluated morphologically, histologically and biochemically.Results Meniscal regeneration was observed as newly synthesized translucent tissue, and image analysis revealed that the amount of this tissue was significantly greater in the HA-treated menisci than in the vehicle-treated menisci. Safranin-O staining and image analysis revealed the increased presence of glycosaminoglycans in the HA-treated menisci relative to vehicle-treated menisci while vascularity and biochemical parameters (hydration, total GAGs and reducible collagen crosslinks) were statistically similar in HA- and vehicle-treated menisci. Gross morphologic grading with India ink revealed a trend for less deterioration of tibial articular cartilage in the HA group (P=0.09) while Mankin's score of the HA-treated tibial articular cartilage was marginally lower than that of the vehicle group (P=0.06). Biochemical assessments showed a trend for higher total GAGs concentration in the HA-treated articular cartilage when compared to the vehicle treatment group (P=0.06).Conclusion The present study has demonstrated that following partial meniscectomy, treatment with hyaluronan can enhance meniscal regeneration and may inhibit articular cartilage degeneration as long as six months post surgery.

The effects of hyaluronan during the development of osteoarthritis

Ninety-nine mature New Zealand White (NZW) rabbits underwent unilateral anterior cruciate ligament transection (ACLT) and were divided into three groups. The contralateral non-operated knees served as controls. The first group (SA) received intra-articular injections of 0.3 ml hyaluronan (HA: MW; 8 x 10(5)) beginning 4 weeks after ACLT, once a week for 5 weeks. The second group (SV) was injected with vehicle (carrier of HA) in the same fashion as the SA group. The third group (SN) served as a nontreatment group post ACLT. All animals were killed 9 weeks post-surgery and were assessed by gross morphology, histomorphometry and biochemical analysis. Gross morphologic changes on the femoral cartilage in the SA group were less severe than those in the SV and SN groups. Cartilage thickness, cartilage area, and thickness of synovial lining cell layer histomorphometric parameters were measured, showing a positive effect of HA on the preservation of articular cartilage and synovial tissue. Similarly, the cartilage and synovial tissues from knees injected with HA did not demonstrate significant alterations from contralateral controls as measured by biochemical analysis [i.e., water content, pyridinoline concentration, glycosaminoglycan (GAG) content for the cartilage, and DNA concentration for the synovial tissue].

Interactions of pentosan polysulfate with cartilage matrix proteins and synovial fibroblasts derived from patients with osteoarthritis

Pentosan polysulfate (PPS) has been shown to improve symptoms of patients with osteoarthritis (OA) when studied under double-blinded conditions. Laboratory studies indicated that this drug exhibits multiple actions, including the preservation of articular cartilage (AC) proteoglycans in animal models of OA and the stimulation of hyaluronan synthesis by synovial fibroblasts in vitro and in vivo. As PPS is strongly anionic and has a molecular weight of approximately 5700 Da its ability to enter connective tissues rich in proteoglycans and interact with the resident cells has been questioned. In the present studies, experiments were undertaken to isolate and characterize proteins in human AC which have the potential to bind PPS. Thrombospondin was identified in 4.0 M GuHCl extracts of human AC as a PPS-binding protein. Furthermore, synovial fibroblasts derived from OA joints were shown to secrete thrombospondin and also bind PPS. Using bovine erythrocytes conjugated with PPS a rosetting of the synovial fibroblast could be demonstrated. The level of rosetting was not affected by pre-incubating cultures with thrombospondin antibody suggesting that PPS was interacting directly with the cells. Kinetic studies of 3H-PPS uptake by synovial fibroblasts showed saturation of binding sites within 30 min when cells were maintained at 4 degrees C but preservation of drug uptake for up to 120 min when cells were cultured at 37 degrees C. These data, together with the finding that cells labeled with drug at 37 degrees C showed higher incorporation, than at 4 degrees C after trypsin digestion suggests that PPS first binds to the cell membrane when at 37 degrees C is internalized, possibly by pinocytosis.

Gogarburn Hospital E-block Positioning Aid

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Treatment of antigen-induced arthritis in rabbits with dysprosium-165-ferric hydroxide macroaggregates.

Dysprosium-165-ferric hydroxide macroaggregates (165Dy-FHMA) was used as an agent of radiation synovectomy in an antigen-induced arthritis model in New Zealand white rabbits. Animals were killed up to 6 months after treatment. 165Dy-FHMA was found to have a potent but temporary antiinflammatory effect on synovium for up to 3 months after treatment. Treated knees also showed significant preservation of articular cartilage architecture and proteoglycan content compared with untreated controls, but only during the first 3 months after treatment. In animals killed 3 and 6 months after treatment there were only minimal differences between the treated and untreated knees, indicating that the antiinflammatory effects on synovial tissue and articular cartilage preservation were not sustained.

Investigational Approaches to Articular Cartilage Preservation

A brief review of articular cartilage preservation identifies several directions and concerns for modern investigators. First, storage of intact cartilage in such solutions as alcohol, merthiolate, plasma, and saline may not be as good as storage in air. Second, viable cartilage appears to fare better than nonviable cartilage after transplantation. Third, freezing of isolated cartilage cells appears to be a satisfactory method for preserving viability, but the same may not be true for cartilage tissue slices, slivers, or explants. Fourth, tissue culture of slices seems to provide excellent preservation of cells in their matrix. Fifth, freezing of intact cartilage presents problems of water diffusion, as well as penetration of cryopreservative. Extremely slow freezing may provide an answer to these problems. Sixth, transplantation of isolated chondrocytes into cartilage defects does not seem to provide regeneration of articular cartilage, but transplantation of slices or larger pieces may restore a more normal appearance to the joint surface. Further investigation is obviously necessary and should continue to provide information and knowledge toward the goal of successful preservation of functional articular cartilage.

Articular cartilage preservation and storage. II. Mechanical indentation testing of viable, stored articular cartilage.

Mature rabbit articular cartilage in the form of distal femoral condyles, composite osteoarticular structures, were incubated in the presence of alpha-tocopherol (200 micrograms/ml) over a period of time. Indentation testing and 35S uptake indicate preservation of sustained load carrying capacity and viability, respectively, in the presence of alpha-tocopherol for up to 30 days in organ culture. Condylar cartilage stored in the absence of alpha-tocopherol as well as frozen cartilage demonstrated progressive inability to resist sustained loading over time. Nonoptimal synthetic function apparently occurred in these latter two groups when compared to alpha-tocopherol stored material.

Articular cartilage preservation and storage. I. Application of tissue culture techniques to the storage of viable articular cartilage.

Articular cartilage slice explants were stored under various conditions, including freezing-thawing at various rates by using dimethyl sulfoxide (DMSO) as a cryoprotective agent, incubating in standard tissue culture medium (MEM Eagle:NCTC 135:15% fetal calf serum) in 5% CO2 and air at 4 degrees, 21 degrees, and 37 degrees C, and incubating in standard tissue culture medium containing 200 micrograms/ml alpha-tocopherol (vitamin E) at 37 degrees C after first ascertaining a dose-response curve of vitamin E. Results indicated that articular cartilage slice explants did not survive freezing or storage at 4 degrees and 21 degrees C as measured by 35S uptake. When stored at 37 degrees C in standard tissue culture in 5% CO2 and air, the slice explants remained viable for up to 60 days. The addition of alpha-tocopherol to the medium resulted in significantly less release of previously incorporated 35Sin stored cartilage slices and significantly less reduction of the amount of hexosamine present in the stored explants. alpha-Tocopherol in the medium also preserved safranin O staining. Thus, the application of tissue culture techniques to the storage of articular cartilage made it possible to preserve cartilage slice explants in a viable, biochemically "normal" state.