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ABSTRACT: OBJECTIVE: Hypercholesterolaemia, a risk factor for atherosclerosis (ATH), has been suggested to have a role in the development of osteoarthritis (OA). To test this hypothesis, the effect of cholesterol and different cholesterol-lowering treatments on OA was investigated in a mouse model resembling human lipoprotein metabolism. METHODS: Female ApolipoproteinE*3Leiden.human Cholesteryl Ester Transfer Protein mice received a western-type diet with 0.1% (w/w) cholesterol (LC), 0.3% (w/w) cholesterol alone (HC) or treated with 3 mg/kg/day atorvastatin or 0.3 mg/kg/day ezetimibe. One group remained on chow (control). After 39 weeks, OA grades of the knees and the extent of ATH were determined. Plasma cholesterol levels were measured throughout the study. RESULTS: LC and HC groups developed significantly more OA at the medial side than the control group in a dose-dependent manner. Atorvastatin but not ezetimibe treatment significantly suppressed OA development. As expected, features of ATH were significantly increased in the LC and HC groups compared with the control group and suppressed by atorvastatin (48%) and ezetimibe (55%) treatment. There were significant correlations between the development of OA on the medial side of the joint and cholesterol exposure (r=0.4) or ATH features (r=0.3). CONCLUSIONS: Dietary cholesterol and accordingly increased plasma levels play a role in the development of OA. The correlation found between OA, cholesterol and ATH demonstrates that these variables are connected, but indicates the contribution of other ongoing processes in the development of OA. The suppressive effect on OA development of atorvastatin but not of ezetimibe, which had similar cholesterol exposure levels, corroborates these findings.
Annals of the rheumatic diseases 04/2013; · 8.11 Impact Factor
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ABSTRACT: OBJECTIVE: Soluble mediators in synovial fluid are acknowledged as key players in the pathophysiology of osteoarthritis (OA). However, a wide-spectrum screening of such mediators in synovial fluid is currently lacking. In this study, the levels of 47 mediators in the synovial fluid of control donors and osteoarthritic (OA) patients were compared. MATERIALS & METHODS: Synovial fluid was collected from control donors (n=16) and end-stage knee OA patients (n=18) and analysed for 47 cytokines, chemokines and growth factors using several multiplex ELISAs. A Mann-Whitney U test was used to determine differences between OA and control controls. A principal component analysis (PCA) was performed to cluster the 47 mediators. RESULTS: The majority of the mediators could be detected in both control and OA synovial fluid. IL-6, IP-10, MDC, PDGF-AA and RANTES levels were found to be higher in OA compared to control synovial fluid (p<0.001). Leptin, IL-13, MIP-1β, sCD40L levels were higher and eotaxin and G-CSF levels were lower in OA synovial fluid than in control synovial fluid, albeit borderline significant (p<0.05). The PCA enabled identification of 6 clusters of mediators, which explained 76% of the variance. CONCLUSIONS: The current study provides the first extensive profile of cytokines, chemokines and growth factors present in control and OA synovial fluid. Increased levels of mediators such as MDC and IL-6 imply involvement of inflammatory processes and might be associated with the influx of inflammatory cells in OA synovial tissue. Moreover, the performed cluster analysis indicated multiple clusters, which could indicate different pathophysiological pathways in the joint.
Osteoarthritis and Cartilage 04/2013; · 3.90 Impact Factor
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ABSTRACT: Macrophages are important in foreign body reactions. We devised a culture model with human primary macrophages to evaluate the acute response of macrophages to biomaterials. First we selected proteins representative for pro-inflammatory (M1) or anti-inflammatory/repair (M2) response of monocytes isolated from blood of healthy human donors by exposing them to LPS+IFNγ or IL-4. A relative M1/M2 index was calculated using IL-1β, IL-6, tumor necrosis factor (TNF)α, monocyte chemotactic protein (MCP)-3 and macrophage inflammatory protein (MIP)-1α as M1 markers, and IL-1 receptor antagonist (IL-1RA), CCL18, regulated and normal T-cell expressed and secreted (RANTES), and macrophage-derived chemokine (MDC) as M2 markers. Then monocytes were cultured for 3 days on 4 materials selected for known different foreign body reactions: Permacol(TM), Parietex(TM) Composite, multifilament polyethylene terephthalate and multifilament polypropylene. Macrophages on polypropylene produced high levels of anti-inflammatory proteins with a low M1/M2 index. Macrophages on Parietex(TM) Composite produced high levels of inflammatory and anti-inflammatory proteins, with a high M1/M2 index. Macrophages on polyethylene terephthalate also resulted in a high M1/M2 index. Macrophages on Permacol(TM) produced a low amount of all proteins, with a low M1/M2 index. This model with human primary macrophages and the panel of read-out parameters can be used to evaluate the acute reaction of macrophages to biomaterials in vitro to get more insight in the foreign body reaction.
Biochemical and Biophysical Research Communications 02/2013; · 2.48 Impact Factor
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ABSTRACT: Although osteoarthritis (OA) is considered a non-inflammatory condition, it is widely accepted that synovial inflammation is a feature of OA. However, the role of immune cells and their cytokines in OA is largely unknown. This narrative systematic review summarizes the knowledge of inflammatory properties, immune cells and their cytokines in synovial tissues (STs) of OA patients.
Broad literature search in different databases was performed which resulted in 100 articles.
Of 100 articles 33 solely investigated inflammation in OA ST with or without comparison with normal samples; the remaining primarily focussed on rheumatoid arthritis (RA) ST. Studies investigating different severity stages or cellular source of cytokines were sparse. OA ST displayed mild/moderate grade inflammation when investigated by means of haematoxylin and eosin (H&E) staining. Most frequently found cells types were macrophages, T cells and mast cells (MCs). Overall the number of cells was lower than in RA, although the number of MCs was as high as or sometimes even higher than in RA ST. Cytokines related to T cell or macrophage function were found in OA ST. Their expression was overall higher than in normal ST, but lower than in RA ST. Their cellular source remains largely unknown in OA ST.
Inflammation is common in OA ST and characterized by immune cell infiltration and cytokine secretion. This inflammation seems quantitatively and qualitatively different from inflammation in RA. Further research is needed to clarify the role of inflammation, immune cells and their cytokines in the pathogenesis of OA.
Osteoarthritis and Cartilage 09/2012; 20(12):1484-99. · 3.90 Impact Factor
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ABSTRACT: Mesenchymal stem cells (MSCs) are promising candidates for osteoarthritis (OA) therapies, although their mechanism of action remains unclear. MSCs have recently been discovered to secrete anti-inflammatory cytokines and growth factors. We studied the paracrine effects of MSCs on OA cartilage and synovial explants in vitro.
MSC-conditioned medium was prepared by stimulating primary human MSCs with tumour necrosis factor alpha (TNFα) and (50ng/ml each). Human synovium and cartilage explants were cultured in MSC-conditioned medium or in control medium, containing the same amount of added TNFα and IFNγ but not incubated with MSCs. Explants were analyzed for gene expression and the production of nitric oxide (NO). The presence of the inhibitor of nuclear factor kappa B alpha (IκBa) was assessed by Western blot analysis.
Synovial explants exposed to MSC-conditioned medium showed decreased gene expression of interleukin-1 beta (IL-1β), matrix metalloproteinase (MMP)1 and MMP13, while suppressor of cytokine signaling (SOCS)1 was upregulated. In cartilage, expression of IL-1 receptor antagonist (IL-1RA) was upregulated, whereas a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)5 and collagen type II alpha 1 (COL2A1) were downregulated. MSC-conditioned medium reduced NO production in cartilage explants and the presence of IκBa was increased in synoviocytes and chondrocytes treated with MSC-conditioned medium.
In an inflammatory environment, MSCs secrete factors which cause multiple anti-inflammatory effects and influence matrix turnover in synovium and cartilage explants. Thereby, the presented data encourage further study of MSCs as a treatment for joint diseases.
Osteoarthritis and Cartilage 07/2012; 20(10):1186-96. · 3.90 Impact Factor
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ABSTRACT: Osteoarthritis (OA) is one of the most prevalent musculoskeletal diseases. Collagen derivatives are candidates for disease-modifying OA drugs. This group of derivatives can be divided into undenatured collagen (UC), gelatine and collagen hydrolysate (CH). Collagen derivatives are marketed as having direct chondroprotective action and reducing complaints of OA. This review summarizes the evidence for the effectiveness of symptomatic and chondroprotective treatment with collagen derivatives in patients with OA.
Eligible randomised controlled trials (RCTs) and quasi-RCTs were identified by searching PubMed, Embase and the Cochrane Central Register of Controlled Trials until November 2011. Methodological quality was assessed using methods of the Cochrane Back Review Group.
Eight studies were identified: six on CH, two on gelatine, and one on UC. The pooled mean difference based on three studies for pain reduction measured with the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index comparing CH with placebo was -0.49 (95% CI -1.10-0.12). However, some studies report significant between-group differences in pain when measured with a visual analogical scale (VAS) or other instruments, or when CH is compared with glucosamine sulphate. For disability no significant between-group mean differences were found when comparing CH with placebo. Gelatine compared with placebo and with alternative therapies was superior for the outcome pain. UC compared with glucosamine+chondroitin showed no significant between-group differences for pain and disability. The most reported adverse events of collagen derivatives were mild to moderate gastro-intestinal complaints. The overall quality of evidence was moderate to very low.
There is insufficient evidence to recommend the generalized use of CHs in daily practice for the treatment of patients with OA. More independent high-quality studies are needed to confirm the therapeutic effects of collagen derivatives on OA complaints.
Osteoarthritis and Cartilage 04/2012; 20(8):809-21. · 3.90 Impact Factor
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L M Gierman,
F van der Ham,
A Koudijs,
P Y Wielinga,
R Kleemann,
T Kooistra,
R Stoop,
M Kloppenburg, G J V M van Osch,
V Stojanovic-Susulic,
T W Huizinga,
A-M Zuurmond
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ABSTRACT: Obesity is associated with systemic inflammation and is a risk factor for osteoarthritis (OA) development. We undertook this study to test the hypothesis that metabolic stress-induced inflammation, and not mechanical overload, is responsible for the development of high-fat diet-induced OA in mice.
Human C-reactive protein (CRP)-transgenic mice received a high-fat diet without or with 0.005% (weight/weight) rosuvastatin or 0.018% (w/w) rosiglitazone, 2 different drugs with antiinflammatory properties. Mice fed chow were included as controls. After 42 weeks, mice were killed and histologic OA grading of the knees was performed. To monitor the overall inflammation state, systemic human CRP levels were determined.
Male mice on a high-fat diet had significantly higher OA grades than mice on chow and showed no correlation between OA severity and body weight. In male mice, high-fat diet-induced OA was significantly inhibited by rosuvastatin or rosiglitazone to OA grades observed in control mice. Both treatments resulted in reduced human CRP levels. Furthermore, a positive correlation was found between the relative individual induction of human CRP evoked by a high-fat diet on day 3 and OA grade at end point.
High-fat diet-induced OA in mice is due to low-grade inflammation and not to mechanical overload, since no relationship between body weight and OA grade was observed. Moreover, the OA process was inhibited to a great extent by treatment with 2 drugs with antiinflammatory properties. The inflammatory response to a metabolic high-fat challenge may predict individual susceptibility to developing OA later in life. The use of statins or peroxisome proliferator-activated receptor γ agonists (e.g., rosiglitazone) could be a strategy for interfering with the progression of OA.
Arthritis & Rheumatism 10/2011; 64(4):1172-81. · 7.87 Impact Factor
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ABSTRACT: Osteoarthritis is the most frequent chronic joint disease causing pain and disability. Besides biomechanical mechanisms, the pathogenesis of osteoarthritis may involve inflammation, vascular alterations and dysregulation of lipid metabolism. As statins are able to modulate many of these processes, this study examines whether statin use is associated with a decreased incidence and/or progression of osteoarthritis.
Participants in a prospective population-based cohort study aged 55 years and older (n=2921) were included. x-Rays of the knee/hip were obtained at baseline and after on average 6.5 years, and scored using the Kellgren and Lawrence score for osteoarthritis. Any increase in score was defined as overall progression (incidence and progression). Data on covariables were collected at baseline. Information on statin use during follow-up was obtained from computerised pharmacy databases. The overall progression of osteoarthritis was compared between users and non-users of statins. Using a multivariate logistic regression model with generalised estimating equation, OR and 95% CI were calculated after adjusting for confounding variables.
Overall progression of knee and hip osteoarthritis occurred in 6.9% and 4.7% of cases, respectively. The adjusted OR for overall progression of knee osteoarthritis in statin users was 0.43 (95% CI 0.25 to 0.77, p=0.01). The use of statins was not associated with overall progression of hip osteoarthritis.
Statin use is associated with more than a 50% reduction in overall progression of osteoarthritis of the knee, but not of the hip.
Annals of the rheumatic diseases 10/2011; 71(5):642-7. · 8.11 Impact Factor
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ABSTRACT: Peroxisome proliferator activated receptor α (PPARα) agonists are used in clinical practice as lipid-lowering drugs and are also known to exert anti-inflammatory effects on various tissues. We hypothesized that PPARα activation leads to anti-inflammatory and anti-destructive effects in human OA cartilage.
Cartilage explants obtained from six OA patients were cultured for 48 h with 10 ng/ml interleukin (IL)1β as a pro-inflammatory stimulus. 100 μM Wy-14643, a potent and selective PPARα agonist, was added to the cultures and gene expression of matrix metalloproteinase (MMP)1, MMP3, MMP13, collagen type II (COL2A1), aggrecan and PPARα in cartilage explants and the release of glycosaminoglycans (GAGs), nitric oxide (NO) and prostaglandin E(2) (PGE(2)) in the culture media were analyzed and compared to the control without Wy-14643.
Addition of Wy-14643 decreased mRNA expression of MMP1, MMP3 and MMP13 in cartilage explants that responded to IL1β, whereas Wy-14643 did not affect gene expression of COL2A1 and aggrecan. Wy-14643 also decreased secretion of inflammatory marker NO in the culture medium of cartilage explants responding to IL1β. Wy-14643 inhibited the release of GAGs by cartilage explants in culture media.
PPARα agonist Wy-14643 inhibited the inflammatory and destructive responses in human OA cartilage explants and did not have an effect on COL2A1 or aggrecan mRNA expression. These effects of PPARα agonists on osteoarthritic cartilage warrant further investigation of these drugs as a potential therapeutic strategy for osteoarthritis (OA).
Osteoarthritis and Cartilage 03/2011; 19(7):895-902. · 3.90 Impact Factor
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ABSTRACT: Human bone marrow stromal-derived mesenchymal stem cells (hBMSCs) will differentiate into chondrocytes in response to defined chondrogenic medium containing transforming growth factor-β (TGFβ). Results in the literature suggest that the three mammalian subtypes of TGFβ (TGFβ1, TGFβ2 and TGFβ3) provoke certain subtype-specific activities. Therefore, the aim of our study was to investigate whether the TGFβ subtypes affect chondrogenic differentiation of in vitro cultured hBMSCs differently. HBMSC pellets were cultured for 5 weeks in chondrogenic media containing either 2.5, 10 or 25 ng/ml of TGFβ1, TGFβ2 or TGFβ3. All TGFβ subtypes showed a comparable dose-response curve, with significantly less cartilage when 2.5 ng/ml was used and no differences between 10 and 25 ng/ml. Four donors with variable chondrogenic capacity were used to evaluate the effect of 10 ng/ml of either TGFβ subtype on cartilage formation. No significant TGFβ subtype-dependent differences were observed in the total amount of collagen or glycosaminoglycans. Cells from a donor with low chondrogenic capacity performed equally badly with all TGFβ subtypes, while a good donor overall performed well. After addition of β-glycerophosphate during the last 2 weeks of culture, the expression of hypertrophy markers was analysed and mineralization was demonstrated by alkaline phosphatase activity and alizarin red staining. No significant TGFβ subtype-dependent differences were observed in expression collagen type X or VEGF secretion. Nevertheless, pellets cultured with TGFβ1 had significantly less mineralization than pellets cultured with TGFβ3. In conclusion, this study suggests that TGFβ subtypes do affect terminal differentiation of in vitro cultured hBMSCs differently.
Journal of Tissue Engineering and Regenerative Medicine 02/2011; 6(1):68-76. · 3.28 Impact Factor
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I R Klein-Wieringa,
M Kloppenburg,
Y M Bastiaansen-Jenniskens,
E Yusuf,
J C Kwekkeboom,
H El-Bannoudi,
R G H H Nelissen,
A Zuurmond,
V Stojanovic-Susulic, G J V M Van Osch,
R E M Toes,
A Ioan-Facsinay
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ABSTRACT: Obesity is a risk factor for the development of osteoarthritis (OA) in hands and knees. Adipose tissue can secrete different adipokines with powerful immunomodulatory effects. The infrapatellar fat pad (IFP) is an intra-articular organ in the vicinity of the synovium and cartilage. It is hypothesised that IFP-derived soluble factors could contribute to pathological processes in the knee joint. A study was therefore undertaken to compare the release of inflammatory mediators in the IFP and subcutaneous adipose tissue (ScAT) and to characterise the adipocytes and immune cell infiltrate in these tissues.
Paired IFP and ScAT samples were obtained from 27 patients with primary OA. The stromal vascular cell fraction (SVF) was isolated and characterised by fluorescence activated cell sorting. Cytokine and adipokine release in fat- and adipocyte-conditioned media was measured by luminex.
IFP secreted higher levels of inflammatory mediators such as interleukin 6 (IL-6), adipsin, adiponectin and visfatin than ScAT. This could be due to differences in the phenotype of adipocytes and/or in the composition and phenotype of the SVF cells. IFP adipocyte-conditioned media showed a trend towards more IL-6 and adipsin than ScAT. Moreover, the SVF fraction of IFP contained more cells/g tissue, a lower percentage of T cells and a higher percentage of mast cells than ScAT. In addition, T cells had a predominantly pro-inflammatory phenotype while macrophages had a mixed pro- and anti-inflammatory phenotype in the IFP.
There are profound differences in secreted inflammatory factors and immune cell composition between the IFP and ScAT. These data indicate that IFP-derived soluble mediators could contribute to pathophysiological processes in the OA knee joint.
Annals of the rheumatic diseases 01/2011; 70(5):851-7. · 8.11 Impact Factor
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Unpublished data. Manuscript submitted. 01/2011;
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Orthopaedic Research SocietyOrthopaedic Research Society, Long Beach, Los Angeles, California, US; 01/2011
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ABSTRACT: Osteoarthritis (OA) of the knee joint is caused by genetic and hormonal factors and by inflammation, in combination with biomechanical alterations. It is characterized by loss of articular cartilage, synovial inflammation and subchondral bone sclerosis. Considerable evidence indicates that the menisci, ligaments, periarticular muscles and the joint capsule are also involved in the OA process. This paper will outline the theoretical framework for investigating the infrapatellar fat pad (IPFP) as an additional joint tissue involved in the development and progression of knee-OA.
A literature search was performed in Pubmed from 1948 until October 2009 with keywords InFrapatellar fat pad, Hoffa fat pad, intraarticular adipose tissue, knee, cartilage, bone, cytokine, adipokine, inflammation, growth factor, arthritis, and OA.
The IPFP is situated intracapsularly and extrasynovially in the knee joint. Besides adipocytes, the IPFP from patients with knee-OA contains macrophages, lymphocytes and granulocytes, which are able to contribute to the disease process of knee-OA. Furthermore, the IPFP contains nociceptive nerve fibers that could in part be responsible for anterior pain in knee-OA. These nerve fibers secrete substance P, which is able to induce inflammatory responses and cause vasodilation, which may lead to IPFP edema and extravasation of the immune cells. The IPFP secretes cytokines, interleukins, growth factors and adipokines that influence cartilage by upregulating the production of matrix metalloproteinases (MMPs), stimulating the expression of pro-inflammatory cytokines and inhibiting the production of cartilage matrix proteins. They may also stimulate the production of pro-inflammatory mediators, growth factors and MMPs in synovium.
These data are consistent with the hypothesis that the IPFP is an osteoarthritic joint tissue capable of modulating inflammatory and destructive responses in knee-OA.
Osteoarthritis and Cartilage 07/2010; 18(7):876-82. · 3.90 Impact Factor
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ABSTRACT: Defects in the assembly and composition of cartilage extracellular matrix are likely to result in impaired matrix integrity and increased susceptibility to cartilage degeneration. The aim of this study was to determine the functional interaction of the collagen fibril-associated proteins type IX collagen and cartilage oligomeric matrix protein (COMP) during cartilage matrix formation.
Primary chondrocytes from mice deficient in type IX collagen and COMP (double-deficient) were cultured in monolayer or alginate beads. Anchorage of matrix proteins, proteoglycan and collagen content, collagen crosslinks, matrix metalloproteinase activity, and mechanical properties of the matrix were measured. Electron microscopy was used to study the formation of fibrillar structures.
In cartilage lacking both type IX collagen and COMP, matrilin 3 showed decreased matrix anchorage. Less matrilin 3 was deposited in the matrix of double-deficient chondrocytes, while larger amounts were secreted into the medium. Proteoglycans were less well retained in the matrix formed in alginate cultures, while collagen deposition was not significantly affected. Electron microscopy revealed similar cartilage collagen fibril diameters in the cultures of double-deficient and wild-type chondrocytes. In contrast, a larger fibril diameter was observed in the matrix of chondrocytes deficient in only type IX collagen.
Our results show that type IX collagen and COMP are involved in matrix assembly by mediating the anchorage and regulating the distribution of other matrix macromolecules such as proteoglycans and matrilins and have counteracting effects on collagen fibril growth. Loss of type IX collagen and COMP leads to matrix aberrations that may make cartilage more susceptible to degeneration.
Arthritis & Rheumatism 11/2009; 60(12):3676-85. · 7.87 Impact Factor
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ABSTRACT: Effects of oxygen tension (pO2) and pH on gene and protein expression and metabolic activity of human chondrocytes were independently assessed. Chondrocytes were cultured under a range of pH (6.4–7.4) and different pO2 (5 and 20%) during 5 days in a bioreactor. Effects on gene expression, DNA content, protein expression, and metabolic activity were determined. Linear regression analysis showed that gene expression of type I collagen (COL1), SOX9, and VEGF is significantly lower at acidic pH, while expression of aggrecan, type II collagen, and HIF1A is pH-independent. Higher protein levels of VEGF were found under low pO2. Acidic pH severely lowered VEGF release into medium, glucose consumption, and lactate production. Extracellular pH proved to more potently influence cell function than oxygen tension, the latter showing down-regulation of COL1 gene expression and up-regulation of VEGF protein under hypoxia. Hypoxic culture inhibits COL1 mRNA expression pH-dependently, while expression of SOX9 is largely hypoxia independent, but pH dependent. Expression of HIF1A and VEGF revealed divergent pH dependencies. Subtle fluctuations in extracellular pH and oxygen tension clearly influence chondrocyte metabolism and marker expression. Sophisticated pH and oxygen control not only allows study of (patho)physiological changes, but also opens new venues in cartilage tissue engineering. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:537–545, 2010
Journal of Orthopaedic Research 10/2009; 28(4):537 - 545. · 2.81 Impact Factor
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ABSTRACT: Effects of oxygen tension (pO(2)) and pH on gene and protein expression and metabolic activity of human chondrocytes were independently assessed. Chondrocytes were cultured under a range of pH (6.4-7.4) and different pO(2) (5 and 20%) during 5 days in a bioreactor. Effects on gene expression, DNA content, protein expression, and metabolic activity were determined. Linear regression analysis showed that gene expression of type I collagen (COL1), SOX9, and VEGF is significantly lower at acidic pH, while expression of aggrecan, type II collagen, and HIF1A is pH-independent. Higher protein levels of VEGF were found under low pO(2). Acidic pH severely lowered VEGF release into medium, glucose consumption, and lactate production. Extracellular pH proved to more potently influence cell function than oxygen tension, the latter showing down-regulation of COL1 gene expression and up-regulation of VEGF protein under hypoxia. Hypoxic culture inhibits COL1 mRNA expression pH-dependently, while expression of SOX9 is largely hypoxia independent, but pH dependent. Expression of HIF1A and VEGF revealed divergent pH dependencies. Subtle fluctuations in extracellular pH and oxygen tension clearly influence chondrocyte metabolism and marker expression. Sophisticated pH and oxygen control not only allows study of (patho)physiological changes, but also opens new venues in cartilage tissue engineering.
Journal of Orthopaedic Research 10/2009; 28(4):537-45. · 2.81 Impact Factor
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ABSTRACT: The use of superparamagnetic iron oxide (SPIO) for labeling cells holds great promise for clinically applicable cell tracking using magnetic resonance imaging. For clinical application, an effectively and specifically labeled cell preparation is highly desired (i.e. a large amount of intracellular iron and a negligible amount of extracellular iron). In this study we performed a direct comparison of two SPIO labeling strategies that have both been reported as efficient and clinically translatable approaches. These approaches are cell labeling using ferumoxides-protamine complexes or ferucarabotran particles. Cell labeling was performed on primary human bone marrow stromal cells (hBMSCs) and chondrocytes. For both cell types ferumoxides-protamine resulted in a higher percentage of labeled cells, a higher total iron load, a larger amount of intracellular iron and a lower amount of extracellular iron aggregates, compared with ferucarbotran. Consequently, hBMSC and chondrocyte labeling with ferumoxides-protamine is more effective and results in more specific cell labeling than ferucarbotran.
Contrast Media & Molecular Imaging 09/2009; 4(5):230-6. · 3.33 Impact Factor
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ABSTRACT: Estrogens are suggested to play a role in the development of osteoarthritis as indicated by the increased prevalence in women after menopause. We studied whether deletion of the estrogen receptor (ER) alpha, beta, or both in female mice results in cartilage damage, osteophytosis, and changes in subchondral bone of skeletally mature animals.
We studied knee joints of 6-month-old female ERalpha-/-, ERbeta-/-, and (double) ERalpha-/-beta-/- mice and their wild type (wt) littermates. The presence and size of osteophytes and osteoarthritic changes in cartilage were analyzed using histology. Changes in subchondral plate and trabecular bone were studied using micro-CT.
In ERalpha-/-beta-/- mice, we observed an increase in number and/or size of osteophytes and thinning of the lateral subchondral plate. However, cartilage damage was not different from wt. In ERalpha-/- or ERbeta-/- mice, no significant differences in cartilage damage score, osteophyte formation, or subchondral plate thickness were found. The bone volume fraction of the epiphyseal trabecular bone was unchanged in ERalpha-/- mice, increased in ERbeta-/- mice, and decreased in ERalpha-/-beta-/- mice.
We conclude that deletion of both ERs leads to increased osteophytosis, but deletion of one or both ERs does not lead to overt cartilage damage in 6-month-old mice.
Osteoarthritis and Cartilage 05/2009; 17(10):1356-61. · 3.90 Impact Factor
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ABSTRACT: The optimal stimulus to repair or regenerate cartilage is not known. We therefore modulated collagen deposition, collagen crosslinking and GAG deposition simultaneously during cartilage matrix production and integrative repair, creating more insight into their role in cartilage repair processes. Insulin-like growth factor 1 (IGF-1; increases proteoglycan and collagen synthesis), beta-aminopropionitrile (BAPN; a reversible inhibitor of collagen crosslinking) and para-nitrophenyl-beta-D-xyloside (PNPX; interferes with proteoglycan production) were used. Bovine articular chondrocytes were cultured in alginate beads for 3 weeks with or without IGF-1, BAPN or PNPX alone and in all possible combinations, followed by 3 weeks in control medium. DNA content, GAG and collagen deposition and collagen crosslinks were determined. Cartilage constructs were cultured under the same conditions and histologically analysed for integration of two opposing cartilage matrices. In alginate cultures, inhibition of collagen crosslinking with BAPN, in combination with promotion of matrix synthesis using IGF1, was most beneficial for matrix deposition. Addition of PNPX was always detrimental for matrix deposition. For integration of opposing cartilage constructs, the combination of BAPN, IGF1 and temporary prevention of proteoglycan formation with PNPX was most beneficial. When a new matrix is produced, proteoglycans are important to retain collagen in the matrix. When two already formed cartilage matrices have to integrate, a temporary absence of proteoglycans and temporary inhibition of collagen crosslinking might be more beneficial in combination with stimulation of collagen production, e.g. by IGF1. Therefore, the choice of soluble factors to promote cartilage regeneration depends on the type of therapy that will be used.
Journal of Tissue Engineering and Regenerative Medicine 01/2009; 3(2):117-23. · 3.28 Impact Factor
