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M Tammi

Publications and source records attributed to M Tammi.

At least 19 recordsLinked to original sources
PubMed2006

Prognostic significance of matrix metalloproteinase-9 (MMP-9) in epithelial ovarian cancer.

OBJECTIVE: We investigated the expression of matrix metalloproteinase-9 (MMP-9) and its relation to clinicopathologic factors and survival and also to previously analyzed expressions of CD44 and hyaluronan in epithelial ovarian cancer. METHODS: The expression of MMP-9 was analyzed immunohistochemically in 292 primary tumors and their 31 metastases. RESULTS: A low proportion of strong MMP-9 expression in cancer cells and high stromal MMP-9 expression correlated with advanced stage of the tumor (p=0.003, p=0.02, respectively). Stromal MMP-9 expression significantly correlated with hyaluronan positivity (p<0.0005), whereas MMP-9 did not correlate with CD44. In univariate analysis, a longer 10-year disease-related survival (DRS) was found in patients with a high proportion of MMP-9 or strong MMP-9 expression in cancer cells (p=0.02, p=0.05, respectively). However, high stromal expression of MMP-9 indicated short DRS (p=0.01). In multivariate analysis of all patients, MMP-9 expressing cancer or stromal cells were not independent prognostic factors, while in FIGO stage I patients a high percentage of MMP-9 positive cancer cells was associated with long DRS (p=0.008). CONCLUSION: These data suggest that MMP-9 has a dual role in tumor progression, acting against tumor advancement when in tumor epithelium and promoting tumor progression while in the stroma.

Adult↗
PubMed2005

Quantitative determination of hyaluronan content in cerebral aneurysms by digital densitometry.

OBJECT: Hyaluronan (HA) is a highly hydrated macromolecule; it is one of the essential components of the extracellular matrix (ECM) of the arteries and plays an important role in maintaining the biomechanical features of blood vessels. Although the potential contribution of HA in aneurysms of different vessels has been studied intensively, no data are available about the alteration of the HA content in the extracellular matrix of intracranial aneurysms. The aim of the study was to determine the hyaluronan content in the wall of human cerebral arteries. METHODS: A biotinylated aggrecan fragment that binds specifically to HA was used to stain samples from cerebral aneurysms (n = 11) to compare the HA content to non-aneurysmal arteries of patients who had intracranial aneurysm (n = 11), and to histologically normal arteries of patients who had expired from non-vascular diseases (n = 14). Digital microscopic densitometry was used for the quantitative analysis of the hyaluronan content in these samples. RESULTS: The highest level (169.5 +/- 7.9) was detected in aneurysms, while the HA-level of non-aneurysmal vessels was lower (130.2 +/- 16.8). Both vessel groups contained significantly higher HA than the normal cerebral arteries (32.9 +/- 2.1). CONCLUSIONS: Results suggest that an elevated hyaluronan level in the extracellular matrix may affect the cerebral arterial wall architecture. It is reasonable to suppose that the increased hyaluronan content creates a viscoelastic ECM which might improve the biomechanical resistance of the thinned vessel wall.

Adult↗
PubMed2005

Elevated expression of hyaluronan and its CD44 receptor in the duodenal mucosa of coeliac patients.

AIMS: Since hyaluronan (HA) metabolism is disturbed in some malignant tumours and in inflammatory diseases, we analysed HA and its receptor CD44 as well as the expression of the Ki67 nuclear protein, a marker of cell proliferation, in histological sections of duodenal biopsies of coeliac disease patients and controls. METHODS AND RESULTS: The study group consisted of 52 patients with coeliac disease in remission, 40 patients with newly diagnosed disease and 10 healthy control subjects. HA was detected with a specific biotinylated probe prepared from cartilage aggrecan and link protein, and CD44 with an antibody recognizing all forms of CD44 and another specific for its v6 variant. For the expression of the nuclear protein, monoclonal antibody MIB-1 was used. The percentage of HA-positive cells in surface epithelium was higher in newly diagnosed patients (13%) compared with patients in remission (11%) and controls (2%). In addition, HA intensity in the lamina propria was decreased in the newly diagnosed patients. In patients with active disease, 22-26% of the surface epithelium was CD44+, whereas the corresponding figure in patients in remission was 5%, and that of controls 1%. The more intensive MIB-1 labelling in the duodenal epithelium of coeliac patients without treatment was normalized after gluten-free diet. CONCLUSIONS: The HA-positive coat on surface epithelium seen even in patients in remission suggests persistent or even permanent changes in the epithelial permeability barrier in coeliac disease.

Adult↗
PubMed2005

Expression of CD 44 s, CD 44 v 3 and CD 44 v 6 in benign and malignant breast lesions: correlation and colocalization with hyaluronan.

AIMS: To examine the expression of CD 44 s, CD 44 v 3 and CD 44 v 6 in breast lesions, and to correlate it with the expression of hyaluronan (HA). METHODS AND RESULTS: CD 44 expression was studied in 75 breast tissue samples, consisting of benign, premalignant and malignant breast lesions, using immunohistochemistry. CD 44 s, but not CD 44 v 3 or CD 44 v 6, was found in the stromal cells, and it was similar in benign and malignant tumours. In benign lesions CD 4 v 6 was detected in 20-30% of the ductal epithelial cells, while C 44 v 3 and CD 44 s were not expressed. CD 44 s, CD 44 v 3 and CD 44 v 6 were all up-regulated in the in situ carcinomas and invasive carcinomas. The level of CD 44 expression in carcinoma cells did not correlate with the type or differentiation of the tumours. CD 44 and HA expression levels were not closely linked in the benign or malignant breast lesions, because HA was overexpressed later in breast cancer progression than CD 44. However, in breast carcinomas CD 44 and HA positivity was often found in the same areas of the sections, and the dual staining confirmed actual colocalization of CD 44 s and HA in the same cells. CONCLUSIONS: CD 44 s, CD 44 v 3 and CD 44 v 6 are up-regulated earlier than HA in breast carcinoma progression, and in later stages they often colocalize with cell surface HA.

Breast Neoplasms↗
PubMed2004

Reduced expression of hyaluronan is a strong indicator of poor survival in oral squamous cell carcinoma.

Several malignant tumours accumulate hyaluronan (HA), a matrix component suggested to promote cancer cell growth and migration. The expression and prognostic value of HA was analysed in a cohort of 151 oral squamous cell carcinoma (SCC) patients with adequate archival tumour material and follow-up data. The tumour samples were stained using a biotinylated HA-specific probe. Normal squamous epithelium showed a strong and homogeneously distributed staining for HA. The most superficial layers were HA-negative. In moderate (n=11) and high grade (n=16) dysplasias an irregular HA staining was observed around invasive cancer. Malignant transformation in oral squamous cell epithelium changed the staining toward irregular with focal reduction of HA. The well (n=92) or moderately differentiated (n=47) carcinomas had a strong HA staining intensity. In poorly differentiated tumours (n=12) the HA staining was weaker and mainly intracellular. The stromal tissue showed usually moderate (n=69) or strong (n=67) HA staining intensity with no statistically significant correlation with the degree of tumour differentiation. At the end of the follow-up (median 52 months) 66 (43%) patients had died because of an oral SCC. A significant difference in overall survival (OS) and disease free survival (DFS) (P=0.0002 and 0.0020, respectively) was noticed between the patients with the different epithelial staining patterns for HA. The reduction of HA staining was associated with poor survival. In Cox's multivariate analysis HA staining was a significant independent predictor of OS (P=0.011) and DFS (P=0.013). These results suggest that HA is a prognostic marker in oral squamous cell carcinoma.

Adolescent↗
PubMed2002

Visualisation of hyaluronan and hyaluronan-binding proteins within ovine vertebral cartilages using biotinylated aggrecan G1-link complex and biotinylated hyaluronan oligosaccharides.

The aim of this study was to localise hyaluronan (HA)-binding proteins (HABPs) in ovine vertebral tissues using biotinylated HA oligosaccharides (bHA oligos) as novel affinity probes and to compare this with the distribution of tissue HA visualised using biotinylated aggrecan G1 domain-link protein complex. The bHA oligos, with a size of 6-18 disaccharides were prepared by partial digestion of HA with ovine testicular hyaluronidase, labelled with biotin hydrazide and purified by a combination of aggrecan G1 domain and avidin affinity chromatography. Hyaluronan and HABPs were both prominent pericellular components of hypertrophic cells of the vertebral epiphyseal growth plate and enlarged cells in the cartilaginous end plate of the disc. The bHA oligo probe also visualised HABPs intracellularly in hypertrophic cells, which also contained intracellular HA. Monolayer cultures of ovine annulus fibrosus and nucleus pulposus cells rapidly internalised the bHA oligo affinity probe which was subsequently visualised by indirect fluorescence using avidin-FITC, to cytoplasm and discrete nuclear regions. The results indicate that the abundant pericellular and intracellular HA associated with cartilaginous cells in the vertebral tissues is colocalised with HABPs. The bHA oligo affinity probe may have further applications in investigations of intracellular HABPs, HA endocytosis and the roles they play in cellular regulatory processes.

Aggrecans↗
PubMed2002

Strong Stromal Hyaluronan Expression Is Associated with PSA Recurrence in Local Prostate Cancer.

OBJECTIVE: HA (hyaluronan) is involved in cell migration, differentiation and cell proliferation, which all are essential to tumour growth. In addition, the cell surface receptor of HA, CD44, is important in cancer cell adhesion, cell migration and tumour neovascularisation. We studied the expression of HA and CD44 and their relationship with other prognostic factors and prostate-specific antigen (PSA) recurrence in local prostate cancer (PC). MATERIALS AND METHODS: 77 PC patients treated with radical prostatectomy were followed-up for a mean of 4 years. HA was detected by using a HA specific probe and CD44 expression was analysed by conventional immunohistochemistry. RESULTS: All specimens expressed HA in tumour stroma and 78% (60/77) of the tumours showed strong stromal expression of HA. The fraction of positively stained specimens for CD44 was 66% (51/77). The strong stromal HA expression was related to perineural infiltration (p = 0.001) and capsule invasion (p = 0.05). No correlation was demonstrated between the stromal HA expression and CD44 expression, preoperative PSA, clinical or pathological T classification, pN status, Gleason grade, seminal vesicle invasion or surgical margin invasion. Reduced CD44 expression was related only to preoperative PSA level (p = 0.008). The PSA recurrence was predicted by strong stromal HA expression, pT classification, seminal vesicle invasion, capsule invasion and surgical margin invasion (p <or= 0.02 for all). pT classification and seminal vesicle infiltration predicted PSA recurrence free survival (RFS). In the multivariate analysis only the seminal vesicle infiltration was an independent predictor of PSA RFS (p = 0.009). CONCLUSION: The strong stromal HA expression was related to PSA recurrence, perineural infiltration and seminal vesicle invasion. Those are the factors related to unfavourable prognosis, but the follow-up period of this series is too short to make definitive prognostic conclusions.

Humans↗
PubMed2001

Hyaluronan enters keratinocytes by a novel endocytic route for catabolism.

Hyaluronan synthesized in the epidermis has an exceptionally short half-life, indicative of its catabolism by epidermal keratinocytes. An intracellular pool of endogenously synthesized hyaluronan, from 1 to 20 fg/cell, inversely related to cell density, was observed in cultured rat epidermal keratinocytes. More than 80% of the intracellular hyaluronan was small (<90 kDa). Approximately 25% of newly synthesized hyaluronan was endocytosed by the keratinocytes and had a half-life of 2-3 h. A biotinylated aggrecan G(1) domain/link protein probe demonstrated hyaluronan in small vesicles of approximately 100 nm diameter close to the plasma membrane, and in large vesicles and multivesicular bodies up to 1300 nm diameter around the nucleus. Hyaluronan did not co-localize with markers of lysosomes. However, inhibition of lysosomal acidification with NH(4)Cl or chloroquine, or treating the cells with the hyaluronidase inhibitor apigenin increased intracellular hyaluronan staining, suggesting that it resided in prelysosomal endosomes. Competitive displacement of hyaluronan from surface receptors using hyaluronan decasaccharides, resulted in a rapid disappearance of this endosomal hyaluronan (t(12) approximately 5 min), indicating its transitory nature. The ultrastructure of the hyaluronan-containing vesicles, co-localization with marker proteins for different vesicle types, and application of specific uptake inhibitors demonstrated that the formation of hyaluronan-containing vesicles did not involve clathrin-coated pits or caveolae. Treatment of rat epidermal keratinocytes with the OX50 monoclonal antibody against the hyaluronan receptor CD44 increased endosomal hyaluronan. However, no CD44-hyaluronan co-localization was observed intracellularly unless endosomal trafficking was retarded by monensin, or cultivation at 20 degrees C, suggesting CD44 recycling. Rat epidermal keratinocytes thus internalize a large proportion of their newly synthesized hyaluronan into non-clathrin-coated endosomes in a receptor mediated way, and rapidly transport it to slower degradation in the endosomal/lysosomal system.

Animals↗
PubMed2001

Extracellular glycosaminoglycans modify cellular trafficking of lipoplexes and polyplexes.

It has been shown that extracellular glycosaminoglycans (GAGs) limit the gene transfer by cationic lipids and polymers. The purpose of this study was to clarify how interactions with anionic GAGs (hyaluronic acid and heparan sulfate) modify the cellular uptake and distribution of lipoplexes and polyplexes. Experiments on cellular DNA uptake and GFP reporter gene expression showed that decreased gene expression can rarely be explained by lower cellular uptake. In most cases, the cellular uptake is not changed by GAG binding to the lipoplexes or polyplexes. Reporter gene expression is decreased or blocked by heparan sulfate, but it is increased by hyaluronic acid; this suggests that intracellular factors are involved. Confocal microscopy experiments demonstrated that extracellular heparan sulfate and hyaluronic acid are taken into cells both with free and DNA-associated carriers. We conclude that extracellular GAGs may alter both the cellular uptake and the intracellular behavior of the DNA complexes.

Adjuvants, Immunologic↗
PubMed2001

Prognostic value of hyaluronan expression in non-small-cell lung cancer: Increased stromal expression indicates unfavorable outcome in patients with adenocarcinoma.

The prognostic value of hyaluronan (HA) was analyzed in a large number of patients (n = 261) with non-small-cell lung cancer (NSCLC) by staining archived tumor samples with a biotinylated HA-specific probe. The level of HA in the tumor cells and surrounding stroma was scored and compared with parallel CD44 stainings, clinicopathological factors and survival data. Adenocarcinomas were characterized by a low percentage of HA-positive cells with low staining intensity compared with squamous-cell and large-cell/anaplastic carcinomas. The HA signal in the peri-tumoral stroma was often higher than that in the uninvolved stroma in all subgroups of NSCLC. CD44 and HA associated with the cancer cells showed a strong positive correlation with each other. In the whole tumor material, dominated by squamous-cell carcinomas (n = 168), recurrences were more often found in cases showing a low percentage of cancer cell-associated HA. However, within the adenocarcinoma subgroup (n = 68), a high percentage of cell-associated HA was correlated with poor tumor differentiation. Also specific for the adenocarcinoma subgroup was the increased number of recurrences in cases with a strong stromal HA signal. In survival analysis of the whole material (n = 189), a low percentage of HA-positive cancer cells was associated with a shortened disease-free survival (DFS) together with stage and tumor type. However, in the subgroup of patients with adenocarcinoma (n = 49), a strong stromal signal for HA predicted poor DFS. The level of HA in the stroma of adenocarcinomas retained its prognostic value in Cox's multivariate analysis. These results indicate that the frequency and intensity of HA has a significant prognostic value in NSCLC, particularly when the histological subtypes are analyzed as separate entities.

Adenocarcinoma↗
PubMed2001

Hyaluronan synthases, hyaluronan, and its CD44 receptor in tissue around loosened total hip prostheses.

Aseptic loosening of prosthetic components, the most common long-term complication after total hip replacement (THR), is characterized by the formation of a synovial membrane-like interface tissue (SMLIT). It was hypothesized that the hyaluronan synthase (HAS)/hyaluronan (HA)/HA receptor CD44 signalling system is responsible for the synovial-like differentiation of the interface membrane. SMLIT was therefore compared with osteoarthritis (OA) synovial membrane by using reverse transcriptase polymerase chain reaction (RT-PCR) of HAS 1, 2 and 3, histochemical HA assay, and immunohistochemistry of CD44 and its non-HA ligands. All three isoforms of HAS were found in these samples. HA and CD44 were most abundant in the lining, but the signal was actually stronger in aseptic loosening than in OA (p<0.01). The non-HA CD44 ligands, collagen type VI, fibronectin, osteopontin, and MCP-1, had a similar distribution pattern in both tissues. These results confirm the synovial-like structure of the interface tissue lining. The pressure waves and movement of the HA-rich pseudosynovial fluid seem to drive HA into the implant-to-host interface, which itself also produces HA. HA may be responsible for the induction of a synovial-like lining at the interface through HA-CD44 signalling.

Adult↗
PubMed2001

Vitamin C enhances differentiation of a continuous keratinocyte cell line (REK) into epidermis with normal stratum corneum ultrastructure and functional permeability barrier.

A continuous rat epidermal cell line (rat epidermal keratinocyte; REK) formed a morphologically well-organized epidermis in the absence of feeder cells when grown for 3 weeks on a collagen gel in culture inserts at an air-liquid interface, and developed a permeability barrier resembling that of human skin. By 2 weeks, an orthokeratinized epidermis evolved with the suprabasal layers exhibiting the differentiation markers keratin 10, involucrin, and filaggrin. Granular cells with keratohyalin granules and lamellar bodies, and corneocytes with cornified envelopes and tightly packed keratin filaments were present. Morphologically, vitamin C supplementation of the culture further enhanced the normal wavy pattern of the stratum corneum, the number of keratohyalin granules present, and the quantity and organization of intercellular lipid lamellae in the interstices of the stratum corneum. The morphological enhancements observed with vitamin C correlated with improved epidermal barrier function, as indicated by reduction of the permeation rates of tritiated corticosterone and mannitol, and transepidermal water loss, with values close to those of human skin. Moreover, filaggrin mRNA was increased by vitamin C, and western blots confirmed higher levels of profilaggrin and filaggrin, suggesting that vitamin C also influences keratinocyte differentiation in aspects other than the synthesis and organization of barrier lipids. The unique REK cell line in organotypic culture thus provides an easily maintained and reproducible model for studies on epidermal differentiation and transepidermal permeation.

Animals↗
PubMed2001

The distribution pattern of the hyaluronan receptor CD44 during human tooth development.

The aim was to investigate the expression pattern of the major cell-surface hyaluronan receptor CD44, as there are no existing data on its presence or absence in human dental structures at different developmental stages. Immunohistochemical localization of CD44 was studied using a monoclonal antibody, H3, that specifically recognizes an epitope in the common backbone of all CD44 isoforms. The dental lamina displayed a strong CD44 signal; the external enamel epithelium was negative. In the coronal region of the tooth germ the presecretory ameloblasts showed an intense reaction whereas the less differentiated inner enamel epithelial cells showed no signal at the cervical loop where they meet the external enamel epithelium. In the stellate reticulum a moderate reaction was detected. The secretory ameloblasts and the stratum intermedium showed a strong cell-surface CD44 signal. A strong signal was also observed on the odontoblasts and their processes. In the pulp, close to the odontoblastic layer, weak labelling was seen in the walls of capillary vessels. The distribution of CD44 in the human tooth germ corresponds to that of hyaluronan in most locations, suggesting that during tooth development this transmembrane protein plays an important part in hyaluronan-mediated events.

Age Factors↗
PubMed2001

High stromal hyaluronan level is associated with poor differentiation and metastasis in prostate cancer.

Several epithelial tumours accumulate hyaluronan (HA) which promotes cancer cell invasion and metastasis. We analysed the expression of HA and its receptor CD44 and their prognostic value in 166 prostate cancer patients followed up for a mean of 13 years; standard deviation (S.D.) 2.7; range 8.7-21.4 years. HA was detected with a specific biotinylated probe prepared from cartilage aggrecan and link protein, and CD44 with an antibody recognising all forms of CD44. The peri- and intratumoral stroma from half of the patients strongly expressed immunohistochemically detectable HA in < or = 15% of the stromal area; the tumours in the remaining half expressed HA in > 15% of the area. The staining of cancer cells for HA was scored positive or negative, and for CD44 the median value of 80% of positive tumour cells was used as a cut-off point. The expression of HA in cancer cells was weakly associated with perineural infiltration of the tumour (P = 0.03) and high Gleason score (P = 0.002). There was also a significant inverse relationship between the expression of HA and CD44 in cancer cells (P < 0.001). The high level of HA in the peri-and intratumoral stroma was related to metastasis, high T-category, high Gleason score, perineural infiltration and high mitotic activity of the tumour (for all P < 0.001). There was a significant inverse relationship between the expression of CD44 in cancer cells and high level of strong expression of HA in the tumour stroma (P < 0.001). A low fraction of CD44-positive cells was related to a high TM-category, high Gleason score and rapid cell proliferation (for all P < 0.0001; M/V P value = 0.0013). In the univariate survival analysis, the high level of strong expression of HA in tumour stroma predicted an unfavourable outcome in the entire series (P = 0.003) and also in the M0 tumours (P = 0.07), while in T1-2 M0 tumours the prognostic value did not reach the level of statistical significance (P = 0.1). A low fraction of CD44-positive cells predicted a poor outcome in the entire series (P < 0.001) and also in M0 tumours (P = 0.003). Cancer cell-associated HA expression had no prognostic value in any tumour categories. In the multivariate analysis of prognostic factors, HA expression in the cancer cells or in the tumour stroma had no additional value to the standard prognostic factors TM-classification, Gleason score and CD44 expression. Our results show that stromal HA accumulation is related to several malignant features and adverse clinical outcome in prostate cancer. However, further studies based on uniformly treated patient cohorts are needed to establish the clinical significance of these findings in current clinical practice.

Adult↗
PubMed2001

Expression of CD44 and its variant isoform v3 has no prognostic value in gastric cancer.

AIMS: To study the controversial role of transmembrane glycoprotein CD44 as a moderator of tumour spread and as a prognostic factor in gastric cancer. METHODS AND RESULTS: The expression of all CD44 forms and that with exon v3 was assessed in 198 stage I-IV gastric adenocarcinomas using immunohistochemistry. CD44 expression was found in 72% and CD44v3 in 55% of the cases. The intensity of CD44 expression was associated with the level of invasion and with hyaluronan expression, while the frequency of CD44 positive cells was not significantly related to any of the clinical or histological features of the tumours. CD44v3 expression failed to show any association with the clinical or histological variables examined. Neither total CD44 nor CD44v3 expression affected survival. The most important prognostic factors in this cohort were the level of invasion, lymph node status, tumour size and vascular or perineural invasion. CONCLUSIONS: Changes in CD44 or CD44v3 expression level do not predict tumour spread or patient survival in gastric cancer.

Adenocarcinoma↗
PubMed2001

MtDNA mutations in maternally inherited diabetes: presence of the 3397 ND1 mutation previously associated with Alzheimer's and Parkinson's disease.

Mutations in the mitochondrial tRNA(leu) (UUR) gene have been associated with diabetes mellitus and deafness. We screened for the presence of mtDNA mutations in the tRNA(leu) (UUR) gene and adjacent ND1 sequences in 12 diabetes mellitus pedigrees with a possible maternal inheritance of the disease. One patient carried a G to A substitution at nt 3243 (tRNA(leu) (UUR) gene) in heteroplasmic state. In a second pedigree a patient had an A to G substitution at nt 3397 in the ND1 gene. All maternal relatives of the proband had the 3397 substitution in homoplasmic state. This substitution was not present in 246 nonsymptomatic Caucasian controls. The 3397 substitution changes a highly conserved methionine to a valine at aa 31 and has previously been found in Alzheimer's (AD) and Parkinson's (PD) disease patients. Substitutions in the mitochondrial ND1 gene at aa 30 and 31 have associated with a number of different diseases (e.g. AD/PD, MELAS, cardiomyopathy and diabetes mellitus, LHON, Wolfram-syndrome and maternal inherited diabetes) suggesting that changes at these two codons may be associated with very diverse pathogenic processes. In a further attempt to search for mtDNA mutations outside the tRNAleu gene associated with diabetes, the whole mtDNA genome sequence was determined for two patients with maternally inherited diabetes and deafness. Except for substitutions previously reported as polymorphisms, none of the two patients showed any non-synonymous substitutions either in homoplasmic or heteroplasmic state. These results imply that the maternal inherited diabetes and deafness in these patients must result from alterations of nuclear genes and/or environmental factors.

Alzheimer Disease↗
PubMed2001

Decline after immobilisation and recovery after remobilisation of synovial fluid IL1, TIMP, and chondroitin sulphate levels in young beagle dogs.

OBJECTIVE: To monitor the concentration of markers of cartilage and synovium metabolism in the knee (stifle) joint synovial fluid of young beagles subjected to immobilisation and subsequent remobilisation. METHODS: The right hind limb of 17 dogs was immobilised in flexion for 11 weeks. Simultaneously, the contralateral left knee was exposed to increased weight bearing. The remobilisation period lasted 50 weeks. Litter mates served as controls. The concentration in joint lavage fluid of interleukin 1alpha (IL1alpha) was measured by immunoassay, the activity of phospholipase A(2) (PLA(2)) was determined by an extraction method, chondroitin sulphate (CS) concentration by precipitation with Alcian blue, hyaluronan (HA) by an ELISA-like assay using biotinylated HA-binding complexes, matrix metalloproteinase 3 (MMP-3), and tissue inhibitor of metalloproteinases 1 (TIMP-1) by sandwich ELISA, and synovitis was scored by light microscopy. RESULTS: Synovitis or effusion was absent in all experimental and control groups. Immobilisation decreased the joint lavage fluid levels of IL1alpha (p<0.05), TIMP (p< 0.05), and the concentration of CS down to 38% (p<0.05) in comparison with untreated litter mates with normal weight bearing. Immobilisation did not affect the activity of PLA(2), or the concentration of MMP-3 or HA in synovial fluid. Joint remobilisation restored the decreased concentrations of markers to control levels. Increased weight bearing did not change the concentrations of markers in comparison with the control joints with normal weight bearing. CONCLUSIONS: 11 weeks' joint immobilisation decreased the concentration of markers of cartilage and synovium metabolism in the synovial fluid, and remobilisation restored the concentrations to control levels. The changes in joint metabolism induced by immobilisation, as reflected by the markers, are thus different from those found in osteoarthritis, where increased levels of these markers are associated with enhanced degradation and synthesis. These findings suggest that the change induced in joint metabolism by immobilisation is reversible in its early stages.

Animals↗