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PubMed1984

Mitogenic effects of hydroxyapatite and calcium pyrophosphate dihydrate crystals on cultured mammalian cells.

Synthetic hydroxyapatite (HA) crystals in 1% serum stimulated 3H thymidine uptake into quiescent canine synovial fibroblasts and human foreskin fibroblast cultures, as did 10% serum. The onset of stimulation and peak uptake of thymidine after crystal addition were delayed by 2-3 hours as compared with the effects produced by 10% serum. Stimulation of 3H thymidine uptake was proportional to the serum concentration used. HA crystals (50 micrograms/ml) stimulated nuclide uptake at each serum concentration used. 3H thymidine uptake was also proportional to the dose of HA or calcium pyrophosphate dihydrate crystals, although larger doses of the latter crystal were required to produce equivalent effects. Not all particulates were effective mitogenic agents. Latex beads and diamond crystals had no effect. Monosodium urate crystals modestly stimulated and calcium urate crystals markedly stimulated nuclide uptake. The more complex crystals found in a naturally occurring condition (calcinosis) were as mitogenic as the pure synthetic HA. The synovial cell hyperplasia sometimes associated with crystals might be explained in part by their mitogenic activity.

Animals↗
PubMed1984

Low incidence of calcium pyrophosphate dihydrate crystal deposition in rheumatoid arthritis, with modification of radiographic features in coexistent disease.

A negative correlation between rheumatoid arthritis (RA) and calcium pyrophosphate dihydrate (CPPD) crystal deposition was demonstrated in separate controlled radiographic and synovial fluid surveys of RA patients aged 55-75 years. Knee chondrocalcinosis was detected in 14% of 135 normal controls and 28% of 87 post-meniscectomy ("joint damage") controls (P less than 0.05), but only 3% of 100 RA and 75 osteoarthritis patients revealed CPPD crystals in 1% and 23%, respectively (P less than 0.01). Ten subjects with coexistent RA and CPPD deposition were also studied; 7 showed radiographic features atypical of RA, including patchy, asymmetric disease, retained bone density, prominent osteophytosis, well-corticated cysts, and paucity of progressive erosive disease. It is suggested that rheumatoid joint damage, unlike that in osteoarthritis, is not conducive to CPPD crystal formation. When RA and CPPD coexist, atypical radiographic features reflecting a hypertrophic reparative response may occur.

Aged↗
PubMed1987

Effect of synthetic calcium pyrophosphate and hydroxyapatite crystals on the interaction of human blood mononuclear cells with chondrocytes, synovial cells, and fibroblasts.

Synthetic calcium pyrophosphate dihydrate crystals and, to a lesser extent, synthetic hydroxyapatite crystals increased the amount of interleukin-1/mononuclear cell factor released by human blood monocytes, as measured by collagenase and prostaglandin E2 production by rabbit chondrocytes, human dermal fibroblasts, and adherent rheumatoid synovial cells. The same crystals also directly induced collagenase and prostaglandin E2 secretion by rabbit chondrocytes, and potentiated the action of interleukin-1/mononuclear cell factor on chondrocytes. These mechanisms may be important in the pathogenesis of the destructive arthropathies associated with these crystals.

Animals↗
PubMed1988

Histologic localization of lipid in the articular tissues in calcium pyrophosphate dihydrate crystal deposition disease.

We demonstrated the histologic localization of lipid in the articular cartilage, meniscus, and synovium in calcium pyrophosphate dihydrate (CPPD) crystal deposition disease, by staining with Sudan III. Almost all the sites of tophus-like deposits of CPPD crystals and the degenerated matrix containing low concentrations of scattered CPPD crystals stained strongly with Sudan III. Transmission electron microscopy demonstrated round or oval lipid droplets in more than half of the chondrocytes around the crystals in each of these tissues. Small lipid droplets were also seen on or around the crystals. These findings suggest that lipids are abundant at the site of CPPD crystal deposition and may be involved in CPPD crystal formation.

Aged↗
PubMed1993

Calcium pyrophosphate dihydrate crystal deposition in synovium. Relationship to collagen fibers and chondrometaplasia.

OBJECTIVE: Reasons for apparent primary deposition of calcium pyrophosphate dihydrate (CPPD) crystals in some synovial membranes have not been systematically examined. We undertook the present study to investigate for and compare possible cellular and matrix factors related to the presence of these crystals in synovium and cartilage. METHODS: Ten synovial membrane specimens and 6 cartilage specimens were obtained at the time of joint surgery from 10 patients with CPPD crystal deposition disease, for light microscopic (LM) and electron microscopic (EM) studies. RESULTS: In all synovial and cartilage specimens, we found many of the small CPPD crystals aligned on or in parallel to collagen fibers, as seen by EM. In 9 of the 10 crystal-containing synovia, we found foci of chondrometaplasia adjacent to CPPD, by LM. In 7 of the synovia, including the one without LM evidence of chondrometaplasia, we observed the presence of chondrocyte-like cells by EM. We did not note any predictable relationship between the crystals and matrix vesicles, either in synovium or in cartilage. CONCLUSION: Our EM findings provide evidence of the relationship of small CPPD-like crystals, presumably early forms, to collagen fibers both in synovium and in cartilage. By LM and EM, we also demonstrate evidence of a close association between chondrometaplasia and CPPD deposits in synovium. We suggest that chondrometaplasia might be responsible for synovial CPPD formation in predisposed patients. Both the collagen fibers and chondrocyte-like cells seem to be involved in the primary formation of CPPD deposits in the synovium as well as in the cartilage.

Aged↗
PubMed2005

Calcium pyrophosphate deposition disease mimicking polymyalgia rheumatica: a prospective followup study of predictive factors for this condition in patients presenting with polymyalgia symptoms.

OBJECTIVE: To assess the characteristics of calcium pyrophosphate deposition disease (CPDD) with proximal involvement mimicking polymyalgia rheumatica (PMR), and to identify the best predictive factors for the presence of a clinical pattern of CPDD in patients presenting with polymyalgia symptoms. METHODS: Patients diagnosed with either PMR or CPDD at the Rheumatology Division of Hospital Meixoeiro (Vigo, Spain) over a 7-year period (1997-2003) were prospectively followed for at least 12 months. RESULTS: The study group comprised 118 patients with PMR features and 112 patients with CPDD. Eighty-two of the 118 patients with PMR manifestations were diagnosed as having pure PMR, and 36 met the diagnostic criteria for both PMR and CPDD. Patients with CPDD mimicking PMR were older (P = 0.02) and had peripheral arthritis more frequently (P = 0.004) than those with pure PMR. Radiologic osteoarthritic changes in the hands and knees, including more advanced radiologic grade of knee osteoarthritis, and tendinous calcifications were more frequent in patients with PMR/CPDD (P < 0.001). The best predictive factors for the occurrence of this atypical pattern of CPDD in a patient presenting with PMR features were the age at diagnosis and the presence of tibiofemoral osteoarthritis, tendinous calcifications, and ankle arthritis. CONCLUSION: Involvement of proximal joints may be the clinical presentation of CPDD. CPDD should be included in the spectrum of diseases mimicking PMR. The presence of tibiofemoral osteoarthritis, tendinous calcifications, and ankle arthritis are clues that may alert the clinician to the presence of CPDD in an elderly patient presenting with PMR manifestations.

Aged↗
PubMed2003

Sugar-mediated chitosan/poly(ethylene glycol)-beta-dicalcium pyrophosphate composite: mechanical and microstructural properties.

The microstructural and mechanical properties of sugar-mediated chitosan/poly(ethylene glycol)-based scaffolds and composites, which are composed of beta-dicalcium pyrophosphate (beta-DCP) and sugar-mediated scaffolds, were investigated. All of the scaffolds were prepared by various freeze-drying protocols. The differences in the freeze-drying process of the sugar-mediated chitosan/poly(ethylene glycol) scaffold for three types of sugar (sucrose, glucose, and D-fructose) were determined by scanning electron microscopic observation, water retention, density, and porosity analyses. The sugar-mediated scaffolds prepared by scheme I of the freeze-drying process show large pores, poorly connective interlayers, and disintegrated inner structures, different from the small pores and well-connective channel structures as shown in the scheme II freeze-drying process. The key factors for controlling pore structure and size in the scheme I freeze-drying process were formulation and composition, but for the scheme II freeze-drying process, the key factor was freeze protocol. The composite scaffolds were macroporous, and the microstructure changed considerably with added beta-DCP content. The incorporation of beta-DCP granules caused a significant enhancement of compressive modulus and yield strength. The increased mechanical strength may be attributable not only to the physical complexation between the sugar-mediated scaffold and beta-DCP, but also the chemical reaction to apatite formed on the cell wall.

Biodegradation, Environmental↗
PubMed2003

The effect of sintered dicalcium pyrophosphate on osteoclast metabolism: an ultrastructural study.

Sintered dicalcium pyrophosphate (SDCP), a synthetic compound, has proved to be both bioabsorbable and biocompatible in vivo. Recent work in our institute also has demonstrated that the ingestion of SDCP can increase bone mass in the ovariectomized rat. In this study, we used an in vitro cell culture model to investigate the ultrastructural changes and fate of osteoclasts induced by SDCP. Quantitative evaluation of osteoblasts and osteoclasts after administration of SDCP was performed. We studied immunohistochemical and ultrastructural features of osteoclasts undergoing apoptosis. The results showed that at 10(-4) M SDCP, the osteoblast cell count increased significantly, whereas the osteoclast population decreased significantly. Apoptosis of the osteoclast population was well demonstrated by immunohistochemical study. Ultrastructural study showed that the Golgi apparatus was degraded or dispersed in the cytoplasm. Later, osteoclasts revealed pyknotic nuclei showing condensation and margination of heterochromatins and DNA fragmentation, which are typical features of apoptosis. In addition, disruption of nuclear envelopes leading to leakage of nuclear contents into the cytoplasm was observed in the late stage of apoptosis. In conclusion, SDCP-induced apoptosis of osteoclasts was characterized by ultrastructural changes of the nucleus accompanied by degradation of cellular organelles.

Animals↗
PubMed2006

Osteoblast response to zirconia-hybridized pyrophosphate-stabilized amorphous calcium phosphate.

Calcium phosphate bioceramics, such as hydroxyapatite, have long been used as bone substitutes because of their proven biocompatibility and bone binding properties in vivo. Recently, a zirconia-hybridized pyrophosphate-stabilized amorphous calcium phosphate (Zr-ACP) has been synthesized, which is more soluble than hydroxyapatite and allows for controlled release of calcium and phosphate ions. These ions have been postulated to increase osteoblast differentiation and mineralization in vitro. The focus of this work is to elucidate the physicochemical properties of Zr-ACP and to measure cell response to Zr-ACP in vitro using a MC3T3-E1 mouse calvarial-derived osteoprogenitor cell line. Cells were cultured in osteogenic medium and mineral was added to culture at different stages in cell maturation. Culture in the presence of Zr-ACP showed significant increases in cell proliferation, alkaline phosphatase activity (ALP), and osteopontin (OPN) synthesis, whereas collagen synthesis was unaffected. In addition, calcium and phosphate ion concentrations and medium pH were found to transiently increase with the addition of Zr-ACP, and are hypothesized to be responsible for the osteogenic effect of Zr-ACP.

Animals↗
PubMed2006

Subcutaneous evaluation of RF magnetron-sputtered calcium pyrophosphate and hydroxylapatite-coated Ti implants.

The in vivo behavior of infrared-heated, RF magnetron-sputtered hydroxylapatite (HA) and calcium pyrophosphate (DCPP) coated titanium discs was investigated. The discs were implanted subcutaneously in the back of six goats for 2, 4, 8 and 12 weeks. At the end of the study, coated discs were removed and examined on their physicochemical properties by X-ray diffraction (XRD) and scanning electron microscopy (SEM), including energy dispersive spectroscopy (EDS). Also, implants were prepared for light microscopical evaluation of the tissue response. The results showed that heat-treated HA coatings showed a stable behavior, i.e. no changes in the XRD pattern occurred during implantation. Also, no dissolution of the coating was observed by SEM. EDS revealed that the Ca/P ratio of the HA coatings remained stable during implantation. In contrast, heat-treated DCPP coatings showed a compositional change into apatite and tricalcium phosphate (TCP) during implantation. This was confirmed by the SEM and EDS analysis. The Ca/P ratio of the DCPP coatings changed from 0.8 to 1.52 during implantation. Finally, histology showed that both heat-treated HA and DCPP coatings showed no adverse tissue response, as characterized by the presence of thin, dense fibrous tissue capsule. Consequently, it can be concluded that 2 mum thick heat-treated, RF magnetron-sputtered HA and DCPP coatings are of sufficient thickness to withstand dissolution during 12 weeks of implantation in a subcutaneous location in goats. In addition, both coatings showed a biocompatible tissue behavior. Further, heat-treated DCPP coatings revealed a gradual compositional change into apatite and TCP.

Animals↗
PubMed1979

Coordinate control of Balb/c3T3 cell survival and multiplication by serum or calcium pyrophosphate complexes.

Balb/c3T3 cells in crowded cultures detach from the dish when deprived of serum, and the survivors incorporate 3H-thymidine at a reduced rate. The detachment becomes pronounced two hours after removal of serum, and reaches its maximum rate between two and four hours. Cells in sparse culture are not detached by serum removal, and their rate of 3H-thymidine incorporation is only slightly reduced. As the sparse cultures grow into more crowded cultures, and the serum is depleted, increasing numbers detach. The detached cells are incapable of reattaching when placed in a new dish with ample fresh serum. The cells are leaky to cellular constituents and appear to be dead. Detachment is a consequence rather than the cause of cell death, and can be produced by agents which inhibit cellular energy metabolism. The cells on the dish which survive serum deprivation are fully viable and grow rapidly when serum is added. When they become crowded they are as sensitive to serum deprivation as was the original population. They are therefore not selected for a low serum requirement but apparently survive because they spread into the space vacated by the detaching cells and then behave as sparse cultures in response to serum variations. Insoluble complexes of Ca2+ and pyrophosphate (Ca2+-PPi) show the same concentration dependence in promoting cell survival as in stimulating 3H-thymidine incorporation, showing that a single substance can be responsible for both activities. It is concluded that survival and growth are part of the coordinate response of 3T3 cells to single external effectors. The results are discussed in terms of a simple model in which the coordinate response is regulated by the availability of Mg2+ for transphosphorylation reactions within the cell, and the availability depends on the binding affinity of cellular membranes for Mg2+. The difference between survival and multiplication is postulated to be in the intensity and duration rather than the kind of stimulus.

Calcium Pyrophosphate↗
PubMed1983

Growth stimulatory precipitates of Ca2+ and pyrophosphate.

Inorganic pyrophosphate (PPi) forms an insoluble precipitate with calcium in growth medium when its concentration exceeds about 0.1 mM. This PPi precipitate can reproduce the effects of 10% calf serum on all cell processes examined in Balb/c 3T3 cells, including hexose uptake and metabolism to lactate, 3H-uridine, and 3H-choline uptake, and the incorporation of 3H-leucine and 3H-thymidine into trichloroacetic acid (TCA)-insoluble material. Concentrations of PPi insufficient to form a precipitate are without effect on cell metabolism. The precipitates are most effective when prepared with concentrations of PPi just sufficient to result in precipitate formation and become considerably less effective as the PPi concentration increases, even though the quantity of precipitate formed continues to increase with PPi concentration up to 1 mM PPi. Precipitates formed at low PPi concentrations consist largely of Ca2+ (81% of cations), PPi (77% of anions), and Pi (23% of anions). Precipitates formed with higher concentrations of PPi contain proportionately less Ca2+ and Pi and more monovalent cations and PPi. We have distinguished cell surface-bound PPi from intracellular PPi by differential extraction. The quantity of surface-bound PPi increases sharply when the PPi concentration reaches the point of precipitate formation. If the precipitate is prevented from binding to the cell surface by inverting monolayer cultures in precipitate-containing medium, the cells are not stimulated. These findings suggest that the binding of PPi precipitate to the cell surface is involved in the stimulation of cell metabolism by PPi. PPi precipitates do not absorb serum mitogens or inhibitors from the culture medium, nor do they affect the binding of 125I-platelet-derived growth factor to its specific cell-surface receptor, suggesting that PPi precipitates do not act directly through either of these mitogen-receptor systems. In analogy to cell stimulation by epidermal growth factor and by antigens, we suggest that PPi may be active only in the form of a precipitate because multivalent binding of receptors with formation of clusters is required for stimulation. The inhibitory effects of high concentrations of PPi may be due to interference by free PPi with formation of active receptor clusters.

Animals↗
PubMed1994

Fructose 3-phosphate and 5-phosphoribosyl-1-pyrophosphate formation in perfused human erythrocytes: 31P NMR studies.

31P NMR was used to study the formation of fructose 3-phosphate (F3P) and 5-phosphoribosyl-1-pyrophosphate (PRPP) in perfused human erythrocytes, in the presence of 10 different combinations and concentrations of glucose, inosine, pyruvate, fructose, and inorganic phosphate (Pi). (1) The cells were immobilized in alginate-coated agarose threads and perfused with a medium containing fructose, and the level of F3P increased continuously over more than 10 h. The net rate of F3P formation was independent of the concentration of 2,3-bisphosphoglycerate (2,3-DPG) present in the cells. (2) PRPP was formed in high concentrations, relative to normal, in immobilized cells when they were perfused with a medium containing Pi at a low pH (6.6). (3) The 2,3-DPG level decreased simultaneously when the sample was perfused with a medium containing fructose, but without inosine or pyruvate. The measured intracellular pH and free Mg2+ concentration were constant in these experiments. (4) The experiments confirmed the presence of fructose-3-phosphokinase (E.C. 2.7.1.-) and ribose-phosphate pyrophosphokinase (E.C. 2.7.6.1) activity in the human erythrocytes and that the biosynthetic pathways are active in immobilized cells at 37 degrees C. (5) The rates of accumulation of 2,3-DPG and phosphomonoesters (PME) appeared to be strongly correlated.

2,3-Diphosphoglycerate↗
PubMed1996

Thiamine pyrophosphate and pyridoxamine inhibit the formation of antigenic advanced glycation end-products: comparison with aminoguanidine.

Nonenzymatic glycation of proteins by glucose leading to the formation of toxic and immunogenic advanced glycation end products (AGEs) may be a major contributor to the pathological manifestations of diabetes mellitus, aging, and, possibly, neurodegenerative diseases such as Alzheimer's. We tested the in vitro inhibition of antigenic AGE formation on bovine serum albumin, ribonuclease A, and human hemoglobin by various vitamin B1 and B6 derivatives. Among the inhibitors, pyridoxamine and thiamine pyrophosphate potently inhibited AGE formation and were more effective than aminoguanidine, suggesting that these two compounds may have novel therapeutic potential in preventing vascular complications of diabetes. An unexpected finding was that aminoguanidine inhibited the late kinetic stages of glycation much more weakly than the early phase.

Animals↗
PubMed1999

Regulatory effect of thiamin pyrophosphate on pig heart pyruvate dehydrogenase complex.

The kinetic behavior of pig heart pyruvate dehydrogenase complex (PDC) containing bound endogenous thiamin pyrophosphate (TPP) was affected by exogenous TPP. In the absence of exogenous TPP, a lag phase of the PDC reaction was observed. TPP added to the PDC reaction medium containing Mg2+ led to a disappearance of the lag phase, inducing strong reduction of the Km value for pyruvate (from 76.7 to 19.0 microM) but a more moderate decrease of Km for CoA (from 12.2 to 4.3 microM) and Km for NAD+ (from 70.2 to 33.6 microM), with no considerable change in the maximum reaction rate. Likewise, thiamin monophosphate (TMP) decreased the Km value of PDC for pyruvate, but to a lesser extent (from 76.7 to 57.9 microM) than TPP. At the unsaturating level of pyruvate, the A50 values for TPP and TMP were 0.2 microM and 0.3 mM, respectively. This could mean that the effect of TPP on PDC was more specific. In addition, exogenous TPP changed the UV spectrum and lowered the fluorescence emission of the PDC containing bound endogenous TPP in its active sites. The data obtained suggest that TPP plays, in addition to its catalytic function, the important role of positive regulatory effector of pig heart PDC.

Adenosine Diphosphate↗
PubMed1993

Aspects of the regulation of hepatic phosphoribosyl pyrophosphate formation in the obese (ob/ob) mouse: relationship to the pentose phosphate pathway.

The content of phosphoribosyl pyrophosphate (PPRibP) and of intermediates involved in its synthesis has been measured in the livers of obese (ob/ob) mice 2 months and 3-4 months of age, a period of dynamic growth and marked hepatic hypertrophy and hyperplasia, and comparison made with the values found in the lean age-matched control groups. The total hepatic PPRibP content and PPRibP/mg DNA was significantly increased in the 3- to 4-month-old obese mice relative to both the lean control groups and the 2-month-old obese mice, illustrating the significant changes occurring in the obese mouse liver in this transition period. The change in hepatic PPRibP/mg DNA in the obese mice is positively correlated with age (up to 4 months, body weight 60 g) and with parameters linked to the activity of the pentose phosphate pathway. There is no apparent correlation between PPRibP concentration and inorganic phosphate, the energy status of the cell, or the hepatic PPRibP synthetase (EC 2.7.6.1.) activity. The increase in the bioavailability of PPRibP, which is both a substrate and activator of the de novo and salvage pathways of purine and pyrimidine synthesis, is considered in relation to the increased nucleotide requirement associated with the rise in total hepatic RNA, DNA, and adenine nucleotide in the obese mouse.

Adenine Nucleotides↗
PubMed1986

Ecto-nucleoside triphosphate pyrophosphohydrolase activity and calcium pyrophosphate dihydrate crystal deposition disease.

Articular cartilage contains any ectoenzyme activity, NTP-PPH, which is capable of generating PPi from NTP substrates. The PPi generated is from the cleavage of the alpha-beta pyrophosphate bond of NTP and does not result from the effects of NTP catabolites. NTP-PPH activity is expressed on human skin fibroblasts in culture and is significantly increased in subjects with CPPD deposition. In addition, cultured fibroblasts from subjects with CPPD disease have higher intracellular PPi concentrations compared to cells from normals and patients with OA. These results support the hypothesis that alterations in PPi metabolism provide the metabolic basis for CPPD deposition.

Adenine Nucleotides↗
PubMed1992

A partial defect in technetium-99m pyrophosphate image suggesting cardiac rupture following acute myocardial infarction.

We present the case of a 70-year-old woman with acute myocardial infarction who died of cardiac rupture on the 2nd hospital day. Dual isotope single photon emission computed tomography (SPECT) using thallium-201 chloride and technetium-99m pyrophosphate (PYP) performed on the 2nd hospital day showed a large perfusion defect in the anteroseptal wall on 201Tl image and a increased accumulation on 99mTc-PYP image in the anterior area consistent with a partial defect. Autopsy performed 1 h after death revealed a tear in the left ventricular anterior wall consistent with the defect on the 99mTc-PYP image. We propose that the finding of a partial defect in 99mTc-PYP is an interesting finding which may be associated with cardiac rupture following acute myocardial infarction.

Aged↗