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Calcium pyrophosphate dihydrate crystal deposition disease: frequency of tendon calcification about the knee.

OBJECTIVE: To delineate the prevalence of tendon and cartilage calcification as well as its possible predilection for age, sex, or side of involvement in calcium pyrophosphate dihydrate (CPPD) crystal deposition disease of the knee. METHODS: We reviewed 225 lateral knee radiographs from 138 patients (M/F: 85/52, 1 unspecified sex, mean age: 73 yrs) to document quadriceps and gastrocnemius tendon calcification. Chondrocalcinosis of the knee was evaluated on 275 knee radiographs (lateral and anteroposterior projection) from 153 patients (M/F: 97/55, 1 unspecified sex, mean age: 73 yrs) to determine the frequency of meniscal and hyaline cartilage calcification. RESULTS: Gastrocnemius tendon calcification was found in 28.4% of knees, which is significantly more common than quadriceps tendon calcification (8.4%). No significant age or laterality difference existed for calcification of either tendon. Quadriceps tendon calcification was more prevalent in men, but no sex difference was present for the gastrocnemius tendon. Calcification of either tendon never occurred without associated chondrocalcinosis. Meniscal calcification was significantly more prevalent than hyaline cartilage calcification; meniscal calcification also was significantly more frequent in men. Increased prevalence of calcification with age was observed in hyaline cartilage but not in the menisci. CONCLUSION: Gastrocnemius tendon calcification is not infrequent in CPPD crystal deposition disease of the knee; identification of such calcification may further delineate this extent of the disorder.

Adult↗

Regulation of alkaline phosphatase: implications for calcium pyrophosphate dihydrate crystal dissolution and other alkaline phosphatase functions.

OBJECTIVE: Alkaline phosphatase (ALP), an enzyme with pyrophosphatase (PPiase) activity can dissolve calcium pyrophosphate dihydrate (CPPD) crystals. We studied the effects of enzyme inhibitors such as bisphosphonates, orthovanadate, calcium, cadmium, and ascorbic acid on PPiase activity of ALP as well as on phosphate ester hydrolysis (Pase) activity and compared these effects to those on CPPD crystal dissolution. METHOD: An in vitro model system for crystal enzyme interaction was used to assess CPPD crystal dissolution. RESULTS: Bisphosphonates inhibited ALP Pase activity more than ALP PPiase activity at the same concentrations. Calcium inhibited ALP PPiase activity, but not ALP Pase activity. Orthovanadate and cadmium inhibited ALP PPiase activity more than ALP Pase at the same concentrations. The inhibition rates of ALP PPiase at the same concentrations were orthovanadate > cadmium > calcium. Although ALP Pase activity was not inhibited, at high concentrations, ascorbic acid slightly inhibited ALP PPiase activity. Bisphosphonates at high concentrations inhibited ALP CPPD crystal dissolution. The strong inhibitory effects of bisphosphonates on ALP CPPD crystal dissolution compared to those on ALP PPiase activity suggest that bisphosphonates inhibit crystal dissolution by their affinity for the CPPD crystal surface. Calcium, orthovanadate, and cadmium inhibited ALP CPPD dissolution. The inhibition rates of ALP CPPD dissolution at the same concentrations were cadmium > calcium > orthovanadate. Ascorbic acid at high concentrations enhanced ALP CPPD dissolution. CONCLUSION: These effects of different inhibitors on ALP PPiase and CPPD dissolution suggest that ALP CPPD crystal dissolution depends on binding of ALP CPPD crystals as well as the PPiase activity of the bound ALP. Because of its ubiquitous and broad phosphatase activity including PPiase activity, ALP may have a critical role in cell energy metabolism.

Alkaline Phosphatase↗

Interaction of dihydroxyethylthiamine pyrophosphate with transketolase.

Deprotonated form of dihydroxyethylthiamine pyrophosphate (DHETPP) is an intermediate product of the transketolase reaction. We have shown that when added to the reaction medium DHETPP can act as a substrate of the holoenzyme. The rate of the enzymatic reaction is quite close to that observed with ordinary substrates of transketolase. This fact suggests that the interaction of DHETPP with the holotransketolase and its deprotonation are not rate-limiting steps of the transketolase reaction.

Apoenzymes↗

Calcium pyrophosphate dihydrate deposition disease presenting as tumoral calcinosis (periarticular pseudogout).

It has been considered unusual for periarticular calcifications to consist of calcium pyrophosphate dihydrate (CPPD). We describe a patient presenting with pain and inflammation adjacent to the site of tumoral calcifications and extending to the first metatarsophalangeal joint. Aspiration of the material revealed weakly positive birefringent rhomboid shaped crystals that proved to be CPPD by atomic force microscopy. The patient had no metabolic abnormalities or radiographic chondrocalcinosis. We believe other cases similar to ours represent another clinical form of CPPD deposition disease-periarticular pseudogout.

Aged↗

Polyamines enhance calcium pyrophosphate dihydrate crystal dissolution.

OBJECTIVE: Alkaline phosphatase (ALP), an enzyme with pyrophosphatase (PP(i)ase) activity, can dissolve calcium pyrophosphate dihydrate (CPPD) crystals. We investigated the CPPD crystal dissolution activity of polyamines, substrates known to enhance PP(i)ase activity. METHODS: An in vitro model system for crystal enzyme interaction was used to assess CPPD crystal dissolution both biochemically and morphologically. RESULTS: We demonstrated biochemically and morphologically that polyamines such as spermine and spermidine can enhance CPPD crystal dissolution activity of ALP. Polyamines enhanced ALP induced CPPD crystal dissolution and ALP PP(i)ase activity differentially. By scanning electron microscopy, we observed that polyamines enhanced dissolution stereoselectively at the small end faces (optical 010 faces) of CPPD crystals, indicated by the presence of etch pits. CONCLUSION: Polyamines assist ALP to promote the stereoselective dissolution of CPPD crystals. In addition to implications for CPPD crystal dissolution, as ALP is present intracellularly, these studies suggest that polyamines and ALP have synergistic effects when ALP PP(i)ase activity is required for intracellular energy metabolism.

Alkaline Phosphatase↗

Monosodium urate, hydroxyapatite, and calcium pyrophosphate crystals induce tumor necrosis factor-alpha expression in a mononuclear cell line.

OBJECTIVE: Tumor necrosis factor-alpha (TNF-alpha) is thought to be important in chronic inflammation of joints characteristic of crystal induced arthritis. Monocytes are instrumental in maintaining that inflammation. We investigated production of mRNA and protein for TNF-alpha in vitro in a murine mononuclear cell line, after exposure to relevant crystal types. METHODS: Using the cell line designated RAW 264.7, cells were grown in standard medium and exposed to varying amounts of monosodium urate (MSU), hydroxyapatite (HA), and calcium pyrophosphate dihydrate (CPPD) crystals for differing time periods. Analysis of TNF-alpha mRNA induced by such exposure was by Northern hybridization; analysis of TNF-alpha protein was by ELISA: RESULTS: RNA analyses of cells treated with various levels of MSU, HA, and CPPD crystals showed strong induction of TNF-alpha transcripts. ELISA on culture supernatants confirmed high level TNF-alpha peptide secretion resulting from that transcriptional upregulation. Time course studies showed peak accumulation of TNF-alpha mRNA 1-6 h post-treatment. Study of the signalling pathway involved in TNF-alpha transcriptional upregulation indicated that increased phospholipase A2 activity was required. CONCLUSION: These observations suggest that crystals in joints can directly stimulate production of TNF-alpha, and that the source of that cytokine may be the monocytes known to be present and playing an important role in chronic joint disease.

Acetophenones↗

[Role of muscle pyruvate dehydrogenase histidine residues in thiamine pyrophosphate binding].

The interaction of diethylpyrocarbonate (DEP) with the pyruvate dehydrogenase component (PDH) isolated from the pyruvate dehydrogenase complex (EC 1.2.4.1) results in a modification of 3-5 histidine residues per mole of enzyme, which simultaneously decreases the enzyme activity. After PDH inhibilion by DEP in the presence of dithiothreitol almost complete reactivation (94%) under the effect of neutral hydroxylamine is observed. In the absence of SH-groups protection incomplete reactivation by hydroxylamine (79%) is found. In the latter case titration with 5,5-dithio--bis-(2-nitrobenzoic acid) in 8 M urea showed that the DEP-modified protein contains less quantity of SH groups (by 4-8) as compared to the native enzyme. It is assumed that the DEP-modified SH-groups are not responsible for the enzyme activity. The differential spectrum of the modified and native PDH showed no changes within the range of 260-300 nm. TPP in combination with Mg2+ (10(-3) M) protectes PDH from being inactivated by DEP. TPP (10(-2) M) reactivates PDH by 70% after its complete inhibition by DEP. Similar protective action is manifested by ATP, ADP and inorganic pyrophosphate in the presence of Mg2+. A kinetic study showed a competitive type of PDH inhibition by DEP with respect to TPP. it is concluded that the histidine residues of PDH are involved in TPP binding.

Catalysis↗

Compressive cervical myelopathy due to calcium pyrophosphate dihydrate deposition disease: report of a case and review of the literature.

Calcium pyrophosphate dihydrate (CPPD) deposition disease is an inflammatory arthropathy that is defined by the deposition of CPPD crystals in articular and periarticular structures. The deposition of CPPD in hyaline cartilage and fibrocartilage leads to the chondrocalcinosis that is characteristic of the disease. It can occur independently or in association with any of a number of inflammatory or endocrine disorders. This form of crystal-induced arthritis tends to affect the peripheral joints, particularly the knees, ankles, shoulders, wrists, and second and third metacarpophalangeal joints, but involvement of the lumbar spine is not uncommon. Cervical spine disease due to CPPD deposition is, however, rare. We report a case of compressive cervical myelopathy due to CPPD deposition disease of the cervical spine in a woman with long-standing rheumatoid arthritis. We also, from a review of the English-language literature, describe the collective reported clinical experience with CPPD deposition disease of the cervical spine.

Aged↗

Differential effects of aging on human chondrocyte responses to transforming growth factor beta: increased pyrophosphate production and decreased cell proliferation.

OBJECTIVE: To address the influence of age on inorganic pyrophosphate (PPi) accumulation in human articular chondrocytes. METHODS: Articular cartilage was obtained from men and women in 2 different age groups: ages 15-55 and 56-91. The effects of transforming growth factor beta1 (TGFbeta1) on PPi levels in the media and cell lysates of chondrocytes were investigated. In addition, the effects of TGFbeta on PPi accumulation were compared with chondrocyte proliferation. RESULTS: TGFbeta1 increased PPi levels to a greater extent in chondrocytes from subjects in the older age group compared with those obtained from younger subjects. Treatment of chondrocytes with TGFbeta1 led to a similar increase in total intracellular protein in both age groups. Although TGFbeta increased nucleoside triphosphate pyrophosphohydrolase activity and decreased alkaline phosphatase activity, these effects did not differ between the 2 age groups. Analysis of the same cell preparations showed an age-related decrease in TGFbeta-induced chondrocyte proliferation, whereas these same cells showed an increased response with respect to PPi elaboration. CONCLUSION: These results show that aging differentially affected TGFbeta-induced PPi accumulation versus proliferation in human articular chondrocytes. These differences in TGFbeta response are likely to contribute to the development of age-associated cartilage diseases such as osteoarthritis.

Adolescent↗

Differential mechanisms of inorganic pyrophosphate production by plasma cell membrane glycoprotein-1 and B10 in chondrocytes.

OBJECTIVE: Increased nucleoside triphosphate pyrophosphohydrolase (NTPPPH) activity in chondrocytes is associated with cartilage matrix inorganic pyrophosphate (PPi) supersaturation in chondrocalcinosis. This study compared the roles of the transforming growth factor beta (TGFbeta)-inducible plasma cell membrane glycoprotein-1 (PC-1) and the closely related B10 NTPPPH activities in chondrocyte PPi metabolism. METHODS: NTPPPH expression was studied using reverse transcriptase-polymerase chain reaction and Western blotting. Transmembrane PC-1 (tmPC-1), water-soluble secretory PC-1 (secPC-1), and transmembrane B10 were expressed by adenoviral gene transfer or plasmid transfection, and expression of PPi was assessed in cultured articular chondrocytes and immortalized NTPPPH-deficient costal chondrocytes (TC28 cells). RESULTS: PC-1 and B10 messenger RNA were demonstrated in articular cartilages in situ, in untreated cultured normal articular chondrocytes, and in TC28 cells. Expression of tmPC-1 and secPC-1, but not B10, rendered the NTPPPH-deficient TC28 cells able to increase expression of extracellular PPi, with or without addition of TGFbeta (10 ng/ml) to the media. More plasma membrane NTPPPH activity was detected in cells transfected with tmPC-1 than in cells transfected with B10. Furthermore, confocal microscopy with immunofluorescent staining of articular chondrocytes confirmed preferential plasma membrane localization of PC-1, relative to B10. Finally, both PC-1 and B10 increased the levels of intracellular PPi, but PC-1 and B10 appeared to act principally in different intracellular compartments (Golgi and post-Golgi versus pre-Golgi, respectively). CONCLUSION: PC-1 and B10 NTPPPH activities were not redundant in chondrocytes. Although increased PC-1 and B10 expression caused elevations in intracellular PPi, the major effects of PC-1 and B10 were exerted in distinct subcellular compartments. Moreover, PC-1 (transmembrane and secreted), but not B10, increased the levels of extracellular PPi. Differential expression of PC-1 and B10 could modulate cartilage mineralization in degenerative joint diseases.

Brefeldin A↗

Exclusion of the gene for human cartilage intermediate layer protein in currently mapped calcium pyrophosphate dihydrate deposition syndromes.

OBJECTIVE: To map the gene for human cartilage intermediate layer protein (CILP) in order to assess its involvement in some familial forms of calcium pyrophosphate dihydrate (CPPD) deposition disease. METHODS: A radiation hybrid panel was analyzed for chromosomal assignment of the CILP gene within a 1-cM limit of resolution. The location of the gene for CILP was confirmed to reside at the observed radiation hybrid locus by fluorescence in situ hybridization. RESULTS: The human CILP gene resides at chromosome 15q21. CONCLUSION: This map location definitively excludes mutations in the CILP gene as the cause of certain familial forms of CPPD deposition disease that have been genetically mapped to chromosomes 8q and 5p.

Base Sequence↗

The effect of dichloromethylene diphosphonate, a pyrophosphate analog, on bone and bone cell structure in the growing rat.

Dichloromethylene diphosphonate (Cl2MDP) is a synthetic compound related in structure to inorganic pyrophosphate but is resistant to enzymatic and chemical degradation and is known to be a potent inhibitor of bone resorption. The administration of 20 mg/kg/day of Cl2MDP for ten days to growing rats results in marked increases in metaphyseal mineralized tissue mass due to slowed bone resorption. There was an increase in resorption areas covering anorganic bone viewed by scanning electron microscopy (SEM), however, the resorption pits, or Howship's lacunae, in these resorption areas were smaller and less defined than those encountered in controls. The appearance of these large areas of poorly delineated resorption pits is likely due to an inhibition of bone resorption coupled with slow bone formation. Administration of Cl2MDP to growing rats also results in an increase in the numbers and size of osteoclasts. Because this would appear to be a histological paradox, in view of the ability of Cl2MDP to slow bone resorption, the osteoclasts were examined by transmission electron microscopy (TEM). The ruffled borders and associated cytoplasmic vacuoles were generally less extensive in the Cl2MDP-treated osteoclasts than in controls, even though clear zones were frequently seen. Examination of undecalcified light microscope sections reveal that the area of bone being degraded by adjacent osteoclasts was generally much smaller in the Cl2MDP-treated animals than in controls. Thus the collaborating TEM observations of smaller ruffled borders, with the SEM observations of smaller, less-defined resorption pits, with the light microscope observations of smaller bone areas being degraded by individual osteoclasts provide a morphological basis for the observed decreases in bone resorption following Cl2MDP administration.

Animals↗

Mutations in the amino terminus of ANKH in two US families with calcium pyrophosphate dihydrate crystal deposition disease.

OBJECTIVE: To analyze ANKH in families with calcium pyrophosphate dihydrate crystal deposition disease (CPPD) for disease-causing mutations. METHODS: Two US families (one of British ancestry and the other of German/Swiss ancestry) with autosomal-dominant CPPD, whose disease phenotypes were found to be linked to chromosome 5p15.1 (locus symbol CCAL2), were screened by direct sequencing for mutations in ANKH, a gene in the CCAL2 candidate interval that has been shown to harbor mutations in other families with CPPD. Observed sequence variants were confirmed by antisense sequencing, and expression of the mutant allele was verified by reverse transcriptase-polymerase chain reaction amplification of messenger RNA followed by direct sequencing. RESULTS: The two US families displayed the same mutation at position 5 of the ANKH gene product (P5T). All affected members were heterozygous for the P-to-T variant, and the mutation was not seen in 204 control alleles. The two families displayed distinct disease haplotypes, suggesting that they were unrelated to each other. CONCLUSION: These observations represent the fourth and fifth families with heritable CPPD whose disease phenotypes are linked to the CCAL2 locus and who have missense mutations in the amino terminus of ANKH. This same position (P5) was the site of a missense mutation in an Argentine family of northern Italian ancestry; however, the sequence variant in that family generated a P5L mutation. The distinct disease haplotypes among the 3 families with P5 mutations suggest that the mutations arose independently and that the evolutionarily conserved P5 position of ANKH may represent a hot spot for mutation in families with autosomal-dominant CPPD.

Chondrocalcinosis↗

Cartilage nucleoside triphosphate pyrophosphohydrolase. II. Role in extracellular pyrophosphate generation and nucleotide metabolism.

Extracellular generation of inorganic pyrophosphate (PPi) in cartilage organ culture is markedly augmented by ATP.ATP, not an ATP metabolite (ADP, AMP, adenosine) is necessary for this augmentation. Excess PPi production is effectively blocked by known inhibitors of nucleoside triphosphate (NTP) pyrophosphohydrolase (EDTA, EGTA, dithiothreitol). Excess 32P-PPi is generated directly from gamma 32P-ATP by cartilage, as substrate and product have similar specific activities. These findings strongly favor ecto-NTP pyrophosphohydrolase as the source of extracellular PPi generation in the presence of NTP. Additionally, active nucleotide and nucleoside catabolism is demonstrated in these cartilage organ cultures.

Adenosine Triphosphate↗

Inorganic pyrophosphate release by rabbit articular chondrocytes in vitro.

Release of inorganic pyrophosphate (PPi) by rabbit articular chondrocytes in vitro was measured by a newly developed assay which utilizes radioactive orthophosphate (32Pi) labeling and anion exchange high performance liquid chromatography. Chondrocytes in monolayer and high density culture failed to release PPi. Explants (cartilage fragments), however, released newly formed PPi into the culture medium. Trypsin treatment of cartilage fragments almost completely blocked the PPi extrusion. Collagenase treatment had no effect on PPi extrusion. There was no clear correlation between proteoglycan synthesis, measured by 35SO4 incorporation, and PPi release. Suppression of proteoglycan synthesis with tunicamycin did not influence the PPi release of the explants.

Animals↗

Acceleration of experimental lapine osteoarthritis by calcium pyrophosphate microcrystalline synovitis.

OBJECTIVE: To investigate the effects of chronic calcium pyrophosphate dihydrate (CPPD) synovitis on the development of osteoarthritic (OA) lesions in an animal model. METHODS: OA was induced in the right knees of 30 male New Zealand white rabbits by partial lateral meniscectomy and section of the fibular collateral and sesamoid ligaments (PLM/LS), followed by 8 weekly intraarticular (IA) injections of 1 mg (low-dose) or 10 mg (high-dose) of CPPD crystals in 3 sets of experiments (10 rabbits each). The contralateral left knees served as controls: experiment 1 PLM/LS alone, experiment 2 8 weekly IA injections of CPPD crystals alone, and experiment 3 sham surgery plus 8 weekly IA injections of CPPD crystals. RESULTS: At 8 weeks, repeated IA injections of low-dose and high-dose CPPD crystals into meniscectomized right knees resulted in more severe OA than in meniscectomized but noninjected left knees (experiment 1) (P = 0.003 and P = 0.001, respectively). One-fourth of the meniscectomized knees (11 of 40), both CPPD-injected and noninjected, showed embedded synovial cartilage shards. CONCLUSION: The data demonstrate a worsening effect of chronic CPPD crystal-induced synovitis on experimental OA produced in the rabbit knees by PLM/LS, and support a possible role for CPPD microcrystalline inflammation in the progression of OA lesions in clinical CPPD crystal deposition disease.

Animals↗

Association of sporadic chondrocalcinosis with a -4-basepair G-to-A transition in the 5'-untranslated region of ANKH that promotes enhanced expression of ANKH protein and excess generation of extracellular inorganic pyrophosphate.

OBJECTIVE: Certain mutations in ANKH, which encodes a multiple-pass transmembrane protein that regulates inorganic pyrophosphate (PPi) transport, are linked to autosomal-dominant familial chondrocalcinosis. This study investigated the potential for ANKH sequence variants to promote sporadic chondrocalcinosis. METHODS: ANKH variants identified by genomic sequencing were screened for association with chondrocalcinosis in 128 patients with severe sporadic chondrocalcinosis or pseudogout and in ethnically matched healthy controls. The effects of specific variants on expression of common markers were evaluated by in vitro transcription/translation. The function of these variants was studied in transfected human immortalized CH-8 articular chondrocytes. RESULTS: Sporadic chondrocalcinosis was associated with a G-to-A transition in the ANKH 5'-untranslated region (5'-UTR) at 4 bp upstream of the start codon (in homozygotes of the minor allele, genotype relative risk 6.0, P = 0.0006; overall genotype association P = 0.02). This -4-bp transition, as well as 2 mutations previously linked with familial and sporadic chondrocalcinosis (+14 bp C-to-T and C-terminal GAG deletion, respectively), but not the French familial chondrocalcinosis kindred 143-bp T-to-C mutation, increased reticulocyte ANKH transcription/ANKH translation in vitro. Transfection of complementary DNA for both the wild-type ANKH and the -4-bp ANKH protein variant promoted increased extracellular PPi in CH-8 cells, but unexpectedly, these ANKH mutants had divergent effects on the expression of extracellular PPi and the chondrocyte hypertrophy marker, type X collagen. CONCLUSION: A subset of sporadic chondrocalcinosis appears to be heritable via a -4-bp G-to-A ANKH 5'-UTR transition that up-regulates expression of ANKH and extracellular PPi in chondrocyte cells. Distinct ANKH mutations associated with heritable chondrocalcinosis may promote disease by divergent effects on extracellular PPi and chondrocyte hypertrophy, which is likely to mediate differences in the clinical phenotypes and severity of the disease.

5' Untranslated Regions↗

Comparative analysis of alpha beta and gamma delta T cell activation by Mycobacterium tuberculosis and isopentenyl pyrophosphate.

Phosphorylated nonpeptide compounds have recently been identified as potent mycobacteria-derived ligands for human V gamma 9/V delta 2-expressing gamma delta T cells. Crude mycobacterial extracts also contain protein antigens which stimulate CD4 alpha beta T cells to produce growth factors that are used by gamma delta T cells for clonal expansion. We have investigated the dynamics in vitro of expansion of CD4 T cells and V gamma 9 cells in cultures of peripheral blood mononuclear cells stimulated with synthetic isopentenyl pyrophosphate (IPP) in the absence or presence of additional stimuli. The results indicated that following stimulation with IPP, gamma delta T cells express CD25 and CD69 antigens, but fail to proliferate unless growth factors are provided exogenously or endogenously through activation of CD4 T cells by additional stimuli such as tetanus toxoid, alloantigen, or superantigens. Furthermore, the presence of antigen presenting cells are required for expansion of gamma delta T cells. In response to IPP stimulation, purified CD4 T cells neither express CD25 or CD69, nor do they proliferate even in the presence of exogenous IL-2. Apart from IL-2, IL-15 and, less efficiently, IL-4, IL-7, and IL-12 can contribute to cellular expansion of IPP-reactive V gamma 9 cells. Together, the results demonstrate that peripheral blood gamma delta T cells proliferate in response to IPP only if CD4 T cells are simultaneously activated by an additional stimulus. This mechanism provides a tight control of the reactivity of gamma delta T cells towards phosphorylated nonpeptide antigens.

Antigen-Presenting Cells↗