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PubMed1996

In serum-free culture thyroid hormones can induce full expression of chondrocyte hypertrophy leading to matrix calcification.

A serum-free culture system has been developed to examine the biologic factors involved in the regulation of cellular maturation, extracellular matrix assembly, and calcification in the physis of the bovine fetal growth plate. Isolated prehypertrophic chondrocytes in high density culture undergo a process of cellular maturation whereby full expression of the hypertrophic phenotype is characterized first by type X collagen synthesis followed by matrix calcification. Using this culture system, we compared the capacity of tri-iodothyronine (T3) with thyroxine (T4) to stimulate expression of the hypertrophic phenotype and matrix calcification in three (B, C, and D) maturationally distinct prehypertrophic chondrocyte subpopulations. The B cell subpopulation was the most mature followed by C and D subpopulations in order of decreasing maturity. Comparisons were made to cultures in fetal calf serum (FCS). In Dulbecco's modified Eagle's medium supplemented with insulin, transferrin, and selenium, both hormones (T3/T4) separately induced, in a dose-dependent manner, chondrocyte maturation to the hypertrophic phenotype characterized by increased type X collagen mRNA and induction of protein synthesis of this molecule, together with increased alkaline phosphatase activity, and eventually calcification of the extracellular matrix. Such cellular maturation to the hypertrophic phenotype was not observed in the absence of T3 or T4 with subpopulations C and D. Only in older fetuses (> 210 days) was this observed and then only in the B subpopulation. Furthermore, T3 was at least 50-fold more potent than T4. The effects of T3 were most pronounced with the most immature cells (subpopulations C and D) where, in the case of the subpopulation C, in contrast to 0.5 nM T3 50 nM T4 was unable to induce expression of the hypertrophic phenotype. Alkaline phosphatase activity was also increased in the C cell subpopulation treated with 1 nM T3 (35.5 U/micrograms of DNA) over that supplemented with 50 nM T4 (7.8 U/micrograms of DNA). Furthermore, matrix calcification, measured by the incorporation of 45Ca2+ into the cell layer, always occurred earlier in cells cultured with T3 compared with T4. Cellular maturation to the hypertrophic phenotype was not accompanied by significant changes in DNA content; this ordinarily increases during culture in the presence of serum. Compared with cells cultured in the presence of serum, either thyroid hormone more potently induced cellular maturation. This study demonstrates that the most immature chondrocytes at the prehypertrophic stage are direct targets for T3 and T4 and, to a much a lesser degree, that either hormone is able to induce full chondrocyte hypertrophy from an early maturational stage leading to matrix calcification. But T3 is much more potent than T4. These studies also offer a new serum-free chemically defined medium containing T3 or T4 for the culture of defined prehypertrophic chondrocytes that supports matrix assembly, hypertrophic expression, followed by matrix calcification.

Animals↗
PubMed1993

The process of calcification during development of the rat tracheal cartilage characterized by distribution of alkaline phosphatase activity and immunolocalization of types I and II collagens and glycosaminoglycans of proteoglycans.

The rat tracheal cartilage was shown to calcify during development. The process of calcification was characterized in terms of distribution of alkaline phosphatase (ALP) activity and alterations to immunolocalization of types I and II collagens and glycosaminoglycans of proteoglycans during the development of the tracheal cartilage, in comparison with calcification of the epiphyseal growth plate cartilage. ALP activity was not identified in the tracheal cartilage in the course of calcification, which therefore differed from that in the growth plate. The tracheal cartilage matrix was not resorbed or invaded by type I collagen during calcification. This suggests that no osteogenesis is involved in calcification of the cartilage. Immunoreactivity for type II collagen became weaker in the central region of the tracheal cartilage during development. No net loss of proteoglycans was identified with Alcian blue staining after calcification of the tracheal cartilage. Immunoreactivity for chondroitin 4-sulphate increased in the calcified tracheal cartilage, while reactivity for chondroitin 6-sulphate was weaker in the calcified area than in the surrounding uncalcified region of the tracheal cartilage. The alteration of the extracellular matrices during development may be involved in the calcification of the rat tracheal cartilage.

Alkaline Phosphatase↗
PubMed1987

A comparative study of the calcification-promoting action of 1,25 (OH)2D3 and calcitonin on the growth cartilage of rats with 1-hydroxyethylidene-1, 1-biphosphonic acid (HEBP)-induced rickets.

When HEBP (1-hydroxyethylidene-1, 1-biphosphonic acid) was administered to young rats in large doses over a short period rickets was consistently produced. When HEBP was administered concomitantly with 1,25 (OH)2D3 or calcitonin (CT), calcification appeared in the growth-plate cartilage where there had been an increase in thickness due to the inhibition of calcification. This experiment was done in an attempt to clarify differences in the calcification-promoting mechanisms of 1,25 (OH)2D3 and CT. The serum alkaline phosphatase level was reduced in rats with an accelerated calcification following the administration of 1,25 (OH)2D3, but there was no reduction in the serum alkaline phosphatase level in rats in which the calcification was accelerated by the administration of CT. The mode of appearance of calcification in the growth-plate cartilage by 1,25 (OH)2D3 or CT differed, depending on the time of administration. These results suggest that mechanisms involved in the enhancement of calcification by 1,25 (OH)2D3 and CT differ in cases where rickets are induced by HEBP.

Alkaline Phosphatase↗
PubMed1992

Diphenylhydantoin inhibits calcification of bovine pericardial implants and myocardium: a preliminary study.

Calcification is a major cause of glutaraldehyde-fixed bioprosthetic valve failure. Recent studies have shown that dystrophic calcification shares basic features with normal bone mineralization, including crystal initiation through the mediation of cell membranes, usually in the form of extracellular vesicles. In this study, we observed that calcification of the myocardium of DBA/2J mice was inhibited or reversed by diets supplemented with 100 mg/kg diet diphenylhydantoin (dilantin) for 70 days, with a calcification incidence of 25% in the dilantin group versus 58% in control. We further studied the effects of dilantin on bioprosthetic valve calcification. Three groups of young male Sprague-Dawley rats (100 g, 9/group) were implanted subcutaneously with 1-cm2 pieces of glutaraldehyde-fixed bovine pericardium. Controls were fed a ground chow for 45 or 90 days postimplantation; experimentals received the same chow for the first 45 days postimplantation and then were fed the same diet supplemented with 1000 mg dilantin/kg for the succeeding 45 days. Calcium content (microgram/mg dry weight) of the implants in the dilantin group was 137 +/- 18.6 versus 214 +/- 34.3 in 90 days control and 79.9 +/- 41.5 in 45 days control (mean +/- SD, P < 0.01 and P < 0.05 respectively, t test). The tibia calcium content of the dilantin group was not significantly different from 90 days control. We conclude that orally administered dilantin inhibits calcification of glutaraldehyde-fixed bovine pericardial implants preferentially. It does not cause decalcification either of implants that have already calcified or of the bones. The anti-calcification effect of dilantin may be associated with its anti-vitamin D effect.

Animals↗
PubMed2006

Mechanisms of the in vivo inhibition of calcification of bioprosthetic porcine aortic valve cusps and aortic wall with triglycidylamine/mercapto bisphosphonate.

Heart valve replacements fabricated from glutaraldehyde (Glut)-crosslinked heterograft materials, porcine aortic valves or bovine pericardium, have been widely used in cardiac surgery to treat heart valve disease. However, these bioprosthetic heart valves often fail in long-term clinical implants due to pathologic calcification of the bioprosthetic leaflets, and for stentless porcine aortic valve bioprostheses, bioprosthetic aortic wall calcification also typically occurs. Previous use of the epoxide-based crosslinker, triglycidyl amine (TGA), on cardiac bioprosthetic valve materials demonstrated superior biocompatibility, mechanics, and calcification resistance for porcine aortic valve cusps (but not porcine aortic wall) and bovine pericardium, vs. Glut-prepared controls. However, TGA preparation did not completely prevent long-term calcification of cusps or pericardium. Herein we report further mechanistic investigations of an added therapeutic component to this system, 2-mercaptoethylidene-1,1-bisphosphonic acid (MABP), a custom synthesized thiol bisphosphonate, which has previously been shown in a preliminary report to prevent bioprosthetic heterograft biomaterial calcification when used in combination with initial TGA crosslinking for 7 days. In the present studies, we have further investigated the effectiveness of MABP in experiments that examined: (1) The use of MABP after optimal TGA crosslinking, in order to avoid any competitive interference of MABP-reactions with TGA during crosslinking; (2) Furthermore, recognizing the importance of alkaline phosphatase (ALP) in the formation of dystrophic calcific nodules, we have investigated the hypothesis that the mechanism by which MABP primarily functions is through the reduction of ALP activity. Results from cell-free model systems, cell culture studies, and rat subcutaneous implants, show that materials functionalized with MABP after TGA crosslinking have reduced ALP activity, and in vivo have no significant calcification in long-term implant studies. It is concluded that bioprosthetic heart valves prepared in this fashion are compelling alternatives for Glut-prepared bioprostheses.

Alkaline Phosphatase↗
PubMed2000

Age-related arterial calcification in rats.

In man, i) arteries calcify with age and ii) age-linked arterial calcification is amplified by vascular pathology such as hypertension or arteriosclerosis. Age-linked arterial calcification has a bad prognosis but drugs to prevent it are lacking. This is partially due to the lack of appropriate animal models. This paper looks at the extent to which arteries calcify with age in the rat and whether hypertension or arteriosclerosis amplifies such calcification. Total calcium levels were determined by acid digestion and flame spectrophotometry and intracellular calcium levels ([Ca2+]i) by the intracellular calcium-sensitive dye, fura-2. Arteries contained up to 5 times more calcium than other soft tissues. Arteries progressively calcified with age whereas other soft tissues did not. Accumulation of calcium with age was essentially extracellular. Hypertension had no effect on age-related arterial calcification. Calcification of the same order as in man was produced in a rat model of arteriosclerosis (vitamin D plus nicotine treatment). In conclusion, as in man, age-linked, organ-specific arterial calcification does occur in rats but its intensity is far less. Arterial calcification of a similar degree to that observed in man can be obtained in rats by hypervitaminosis D plus nicotine.

Aging↗
PubMed2005

Inducers and inhibitors of biomineralization: lessons from pathological calcification.

OBJECTIVES: Ectopic calcification is a common response to soft tissue injury and systemic mineral imbalance and can lead to devastating clinical consequences when present in joints, heart valves and blood vessels. We have hypothesized that mineralization of matrices in any tissue is normally controlled by a balance between procalcific and anticalcific regulatory proteins such that abnormal deposition of apatite is avoided. Alterations in this balance induced by injury, disease or genetic deficiency are postulated to induce ectopic mineral deposition. Over the past several years, we have developed in vitro and in vivo models of ectopic calcification to investigate potential inducers and inhibitors of this process. RESULTS: Osteopontin, a secreted phosphoprotein, has emerged as a major inhibitor of ectopic mineralization. Osteopontin is a potent inhibitor of vascular cell calcification in vitro and mice lacking osteopontin are highly susceptible to ectopic calcification. Furthermore, osteopontin treatment of biomaterials protected against ectopic mineralization. Our studies indicate that in addition to inhibiting apatite crystal initiation and growth, osteopontin stimulates resorption of ectopic calcification via peripheral macrophages and giant cells. In contrast, inorganic phosphate has emerged as a major inducer of mineralization in these systems. Elevated inorganic phosphate (Pi) was shown to induce smooth muscle cell matrix calcification with morphological properties similar to those observed in calcified human valves and atherosclerotic plaques. Furthermore, mineralization induced by inorganic phosphate was dependent on the activity of the sodium-dependent phosphate cotransporter, Pit-1. CONCLUSIONS: These studies implicate controlled, transcellular transport of Pi as a major requirement for matrix calcification.

Animals↗
PubMed2006

In vitro evaluation for potential calcification of biomaterials used for staple line reinforcement in lung surgery.

Bovine pericardium (BPC) and polytetrafluoroethylene (PTFE) have been widely used to reinforce staple lines in lung resection. Since limited information regarding the calcification of these biomaterials is available, we undertook an in vitro study to evaluate their calcification potential. Commercially available BPC and PTFE biomaterials were evaluated and compared with custom-prepared BPC tissue. In vitro calcification was performed via submersion in supersaturated solution in a double-walled glass reactor at 37.0 degrees C +/- 0.1 degrees C, pH 7.4 +/- 0.1, mimicking most ion concentrations of human blood plasma. In processing of calcification, the pH decrease of the solution simulated the addition of consumed H(+), Ca(2+), and PO(4)(3-) ions from titrant solutions, the concentrations of which were based on the stoichiometry of octacalcium phosphate. The molar ion addition with time was recorded, and the initial slope of the curve was computed for each experiment. The rate of calcification developed (molar calcium phosphate ion addition rate per time and total surface area) (R) was computed after that with respect to the relative supersaturation (sigma) used in each experiment. R for custom-prepared BPC tissues was found to be in the range of 0.19 +/- 0.08 to 0.52 +/- 0.19 (n = 17) in sigma range of 0.72 to 1.42. Commercial BPC was found to be 0.016 to 0.052 (n = 4), and PTFE was 0.005 to 0.05 (n = 8) in the same sigma range. Both clinically applied biomaterials, BPC and PTFE, seemed to be calcified with rates of at least one order of magnitude lower than the custom-prepared BPC tissue. This data suggested that BPC and PTFE biomaterials showed a similar, relatively very low tendency for calcification compared with custom-prepared BPC tissue. Although further studies are necessary, staple line reinforcement by these two biomaterials should be considered safe from the calcification point of view.

Animals↗
PubMed2000

Sources and mechanisms of inorganic carbon transport for coral calcification and photosynthesis.

The sources and mechanisms of inorganic carbon transport for scleractinian coral calcification and photosynthesis were studied using a double labelling technique with H(14)CO(3) and (45)Ca. Clones of Stylophora pistillata that had developed into microcolonies were examined. Compartmental and pharmacological analyses of the distribution of(45)Ca and H(14)CO(3) in the coelenteron, tissues and skeleton were performed in dark or light conditions or in the presence of various seawater HCO(3)(-) concentrations. For calcification, irrespective of the lighting conditions, the major source of dissolved inorganic carbon (DIC) is metabolic CO(2) (70-75% of total CaCO(3) deposition), while only 25-30% originates from the external medium (seawater carbon pool). These results are in agreement with the observation that metabolic CO(2) production in the light is at least six times greater than is required for calcification. This source is dependent on carbonic anhydrase activity because it is sensitive to ethoxyzolamide. Seawater DIC is transferred from the external medium to the coral skeleton by two different pathways: from sea water to the coelenteron, the passive paracellular pathway is largely sufficient, while a DIDS-sensitive transcellular pathway appears to mediate the flux across calicoblastic cells. Irrespective of the source, an anion exchanger performs the secretion of DIC at the site of calcification. Furthermore, a fourfold light-enhanced calcification of Stylophora pistillata microcolonies was measured. This stimulation was only effective after a lag of 10 min. These results are discussed in the context of light-enhanced calcification. Characterisation of the DIC supply for symbiotic dinoflagellate photosynthesis demonstrated the presence of a DIC pool within the tissues. The size of this pool was dependent on the lighting conditions, since it increased 39-fold after 3 h of illumination. Passive DIC equilibration through oral tissues between sea water and the coelenteric cavity is insufficient to supply this DIC pool, suggesting that there is an active transepithelial absorption of inorganic carbon sensitive to DIDS, ethoxyzolamide and iodide. These results confirm the presence of CO(2)-concentrating mechanisms in coral cells. The tissue pool is not, however, used as a source for calcification since no significant lag phase in the incorporation of external seawater DIC was measured.

Animals↗
PubMed2000

Sonographic appearance of cricoid cartilage calcification in healthy children.

OBJECTIVE: The purpose of this study was to determine the distribution pattern of calcification in cricoid cartilage of healthy children. SUBJECTS AND METHODS: Sonography of the neck was performed with a high-resolution linear array transducer to show the sides of the cricoid cartilage ring in both the sagittal and transverse planes. Twenty-three boys and 33 girls, who ranged in age from 6 to 17 years, were examined. Calcifications in the cartilage were characterized by number and size, distribution pattern, and side-to-side symmetry. RESULTS: Calcifications were seen either as small echogenic, nonshadowing foci or as larger irregular, echogenic areas with acoustic shadowing. Calcifications were found in 19 of the 23 boys and 26 of the 33 girls. The earliest cases were in three 7-year-old children. The incidence and number of echogenic foci generally increased with age. Most calcifications were in the center of the cartilage or distributed diffusely throughout. Side-to-side comparison of the number, size, and distribution pattern of the calcifications showed considerable variation. CONCLUSION: The sides of the cricoid cartilage ring could be seen on sonography in both the sagittal and transverse planes. Calcifications within the cartilage were readily shown and were found in children at an earlier age than previously reported.

Adolescent↗
PubMed2005

Mechanisms of vascular calcification in renal disease.

Vascular calcification is commonplace in patients with end-stage renal disease where it develops rapidly and predicts a variety of adverse outcomes. The processes responsible for vascular calcification have been the focus of much research, aided in recent decades by molecular genetic techniques and in vitro models. Converging evidence now suggests that vascular calcification is an active, regulated process, with abundant similarities to the process of skeletal mineralization. Using an in vitro model of calcifying vascular smooth muscle cells (VSMCs), we have shown that a mineral imbalance induces VSMC apoptosis, and that VSMC apoptotic bodies and vesicles can nucleate basic calcium phosphate in the form of hydroxyapatite, the same mineral found in bone. Gene expression studies suggest that the normal vessel wall expresses proteins such as matrix Gla protein that inhibit calcification. In addition, circulating proteins such as fetuin-A are produced at remote sites and act to inhibit soft tissue calcification systemically. However, down-regulation or perturbation of these proteins may lead to a phenotypic transformation of VSMCs to osteo/chondrocytic-like cells while the calcified environment may stimulate macrophages to adopt osteoclastic properties. Both clinical and basic research findings indicate an inverse relationship between bone mineralization and vascular calcification. The mechanisms linking these two processes are a topic for further investigation, with current theories proposing a role for lipids, common regulatory molecules, and calcium and bone turnover. We have synthesized these findings into a theoretical model offering a putative pathway for the development of severe vascular calcification in end-stage renal disease.

Animals↗
PubMed1990

Pulp calcifications in primary teeth.

One hundred and twenty primary maxillary and mandibular extracted teeth were collected to study the occurrence and nature of pulp calcifications. The teeth were serially sectioned, stained with hematoxylin and eosin, examined by light microscope. Pulp calcifications were observed in 31 (25.8%) teeth. Two types of pulp calcifications were noticed i.e., diffuse calcifications and free/attached type denticles. The occurrence of pulp calcification appears identical in all teeth except in the first primary molar which is statistically not significant (P greater than 0.05). The low prevalence of pulp calcifications in the primary teeth support the view that pulp calcification increases as the age advances.

Dental Pulp Calcification↗
PubMed1988

Mechanisms of pathologic calcification.

Pathologic calcification usually is initiated by the biologic membranes of mitochondria or matrix vesicles. Mitochondria frequently initiate intracellular calcification. Matrix vesicles, derived from the outer membrane of cells by budding or cell disruption, initiate extracellular calcification in calcific tendonitis, apatite-deposition osteoarthritis, atherosclerosis, cardiac valvular calcification, tympanosclerosis, and other calcific diseases. Matrix vesicles and mitochondria usually initiate calcification through the interaction of phosphatase enzymes with calcium-binding phospholipids, both of which are membrane-bound. Hydroxyapatite (HA) crystals are formed first within the protective microenvironment of the membrane-enclosed microspace. Once formed and exposed to the extracellular fluid, HA crystals can serve as nuclei or templates, thus supporting progressive, autocatalytic mineral crystal proliferation.

Arthritis↗
PubMed1993

[Cell mediated calcification in three-dimensional collagen gel culture of the osteoblast-like cells derived from rat calvaria].

Osteoblast-like cells were obtained by sequential enzymatic digestion of 19-day fetal rat calvaria and cultured within native type 1 collagen gels in alpha-MEM supplemented with 10% fetal bovine serum and 10 mM beta-glycerophosphate for 3 weeks. Cells were also cultured as monolayers in the usual manner and used as controls. The collagen gel discs contracted by one tenth in diameter after 4 days. The cells in the collagen gels seemed to proliferate at a low rate and to differentiate immediately into round cells, spindle-like cells, and adipocytes. In the monolayer cultures, calcifications were recognized after 2 weeks only in the high-density confluent areas where cells were disposed in multiple layers and alkaline phosphatase activity was high. In the collagen gels, some cells showed high alkaline phosphatase activity after 1 day of culture and calcifications were observed after 1 week around the cells with intense alkaline phosphatase activity. In collagen gel cultures, the degree of alkaline phosphatase activity and of calcification correlated with the density of the cell suspension at the time of seeding. The round cells were thought to be osteoblasts since they showed high alkaline phosphatase activity and were closely related to initial calcifications. Some of the spindle-like cells also showed high alkaline phosphatase activity and were apparently involved in the calcification process in the latter phase of culture, so that some of them seemed to be resting osteoblasts or lining cells. In electron-microscopical studies, initial calcification was related to the so-called matrix vesicles, and hydroxyapatite crystals were detected in mitochondria. Gap junctions which are specific to osteocytes were observed mainly between the round cells, but also between the round cells and the other cells. This culture system in which cells form a three-dimensional network is suitable to investigate osteoblastic functions and cell mediated calcification in vitro.

Alkaline Phosphatase↗
PubMed1997

Estimation of sex and age by calcification pattern of costal cartilage in Japanese.

The right 4th costal cartilages of 110 Japanese cadavers (55 males and 55 females) were radiographically examined to elucidate the sex differences in the pattern of calcification. Calcification was observed in the cartilages of both sexes aged over 20 years. Twenty out of 98 subjects showed no calcification despite being over 20 years old; so calcification at this site did not occur with aging in all adults, but was seen in approximately 80%. Calcification showed 3 patterns, which were marginal, central, and granular calcification pattern. The marginal pattern was observed in 39 subjects (33 males and 6 females), the central pattern in 15 (all female) and the granular pattern in 20 (1 male and 19 females). Detailed investigation of the internal structure at the distal ends of the ribs and the shape of the costochondral junction revealed better estimates of age compared with the degree of calcification alone, which showed wide individual variation. Radiographic examination of the costal cartilages is useful and conveniet for estimating the sex and age, not only of fragmentary and partial remains, but also of skeletons or badly decomposed bodies. Moreover, it may be effective as a screening test for identification after large-scale disasters.

Adolescent↗
PubMed2001

Sclerochoroidal calcification: clinical manifestations and systemic associations.

BACKGROUND: Sclerochoroidal calcification is an unusual ocular condition that is believed to be idiopathic in most cases. OBJECTIVES: To describe the clinical manifestations of sclerochoroidal calcification and to investigate its possible systemic associations. METHODS: This noncomparative consecutive case series included patients diagnosed as having sclerochoroidal calcification based on clinical characteristics and diagnostic test findings. We analyzed the demographic, systemic, and ocular features of 27 such patients. Systemic evaluation included tests for calcium-phosphorus metabolism in 19 patients and renal tubular hypokalemic metabolic alkalosis syndromes (Bartter or Gitelman syndrome) in 13. RESULTS: All the patients were asymptomatic older (mean age, 70 years) white individuals, incidentally noted as having a choroidal lesion on routine examination. Among 38 eyes, the main referral diagnoses were choroidal metastasis in 10 eyes (26%), choroidal melanoma in 8 (21%), and choroidal nevus in 4 (11%). Sixteen patients (59%) had unilateral clinical findings, while 11 (41%) had bilateral. The Snellen visual acuity was 20/50 or better in 37 eyes (97%). Cogan scleral plaque was visible anterior to the insertion of horizontal rectus muscles in 10 eyes (26%). Among 77 foci, there were a mean of 2 foci of sclerochoroidal calcification in each eye, 41 yellow (53%), 32 yellow-white (42%), 2 white (3%), and 2 orange (3%), measuring a mean 2.6 mm in diameter and 1.1 mm in thickness. The most common locations were postequatorial in 45 (58%), along the temporal vascular arcades in 30 (39%), and in the superotemporal quadrant in 43 (56%). A-scan and B-scan ultrasonography revealed dense echoes compatible with calcium, with orbital shadowing. All the lesions remained stable in size and configuration during a mean follow-up of 38 months. One patient developed a choroidal neovascular membrane over the area of sclerochoroidal calcification. Investigations for abnormal calcium-phosphorus metabolism in 19 patients revealed primary hyperparathyroidism in 1 patient (5%). Clinical and biochemical evaluation of 13 patients demonstrated hypomagnesemia in 6 (46%). Four patients (31%) met the criteria for the diagnosis of Gitelman syndrome. CONCLUSIONS: Sclerochoroidal calcification usually manifests as multiple discrete yellow placoid lesions in the midperipheral fundus of asymptomatic older white individuals. Although most cases may be idiopathic in nature, some patients may have underlying systemic disorders involving abnormal calcium-phosphorus metabolism or renal tubular hypokalemic metabolic alkalosis syndromes. All patients with sclerochoroidal calcification should be tested for these treatable systemic associations.

Adult↗
PubMed2000

Calcification of the aortic arch: risk factors and association with coronary heart disease, stroke, and peripheral vascular disease.

CONTEXT: Calcium deposits in coronary and extracoronary arterial beds may indicate the extent of atherosclerosis. However, the incremental predictive value of vascular calcification, beyond traditional coronary risk factors, is not clearly established. OBJECTIVE: To evaluate risk factors for aortic arch calcification and its long-term association with cardiovascular diseases in a population-based sample. DESIGN AND SETTING: Cohort study conducted at a health maintenance organization in northern California. PARTICIPANTS: A total of 60,393 women and 55,916 men, aged 30 to 89 years at baseline who attended multiphasic health checkups between 1964 and 1973 and for whom incidence of hospitalizations and/or mortality data were ascertained using discharge diagnosis codes and death records through December 31, 1997 (median follow-up, 28 years). MAIN OUTCOME MEASURE: Hospitalization for or death due to coronary heart disease, ischemic stroke, hemorrhagic stroke, or peripheral vascular disease, as associated with aortic arch calcification found on chest radiograph at checkup from 1964-1973. RESULTS: Aortic arch calcification was present in 1.9% of men and 2.6% of women. It was independently associated with older age, no college education, current smoking, and hypertension in both sexes, but it was inversely related to body mass index and family history of myocardial infarction. In women, aortic arch calcification was also associated with black race and elevated serum cholesterol level. After adjustment for age, educational attainment, race/ethnicity, cigarette smoking, alcohol consumption, body mass index, serum cholesterol level, hypertension, diabetes, and family history of myocardial infarction, aortic arch calcification was associated with an increased risk of coronary heart disease (in men, relative risk [RR], 1.27; 95% confidence interval [CI], 1.11-1.45; in women, RR, 1. 22; 95% CI, 1.07-1.38). Among women, it was also independently associated with a 1.46-fold increased risk of ischemic stroke (95% CI, 1.28-1.67). CONCLUSION: In our population-based cohort, aortic arch calcification was independently related to coronary heart disease risk in both sexes as well as to ischemic stroke risk in women. JAMA. 2000;283:2810-2815

Adult↗
PubMed1997

Synergistic inhibition of calcification of porcine aortic root with preincubation in FeCl3 and alpha-amino oleic acid in a rat subdermal model.

Postimplant calcific degeneration is a frequent cause of clinical failure of glutaraldehyde crosslinked porcine aortic valve bioprostheses. We demonstrated previously in rat subdermal and circulatory implants that alpha-amino oleic acid used as a bioprosthesis pretreatment was highly effective in mitigating aortic valve cusp but not aortic wall calcification. In this study we investigated the feasibility of synergistically applying two proven anticalcification agents (alpha-amino oleic acid and FeCl3) as pretreatments for mitigating both bioprosthetic cusp and aortic wall calcification. alpha-Amino oleic acid is hypothesized to prevent calcification by disrupting calcium phosphate formation kinetics, whereas suppression of alkaline phosphatase activity and ferric-phosphate complexation at a cellular membrane initiation sites may be important factors in ferric ion's inhibition of calcification. In vivo implant studies (21-day rat subdermal model) indicated that individually FeCl3 (0.01 or 0.1 M for 24 h) or alpha-amino oleic acid (saturated solution) treatments were equally effective in mitigating cuspal calcification (tissue calcium levels: 30.2 +/- 10.2, 29.8 +/- 2.7, and 31.6 +/- 7.8 micrograms/mg tissue, respectively). However, sequential application of first alpha-amino oleic acid and then FeCl3 synergistically reduced aortic wall calcification more effectively than either of the agents alone. The benefit of a synergistic application of two anticalcification treatments, alpha-amino oleic acid and FeCl3, was demonstrated. However, the synergistic effect was observed on aortic wall only at a higher FeCl3 concentration. (i.e., 0.1 M).

Animals↗