acid-phosphatase and Osteogenesis-Imperfecta

Initial studies indicated that bone and cartilage, when treated with a hypertonic glutaraldehyde fixative for a short period, retained significant enzyme activity for histochemistry and also maintained excellent fine structure. We used 6% glutaraldehyde in 0.1 M cacodylate buffer, pH = 7.2, 4 degrees C to fix small pieces of bone or cartilage for three hours while the tissues were being constantly agitated. These samples were demineralized in 10% ethylene diamine tetraacetic acid, buffered to pH = 7.2 with 0.1 M Tris HC1, at 4 degrees C. The demineralized tissue was frozen and cryostat sections 32 microns thick were taken for incubation at 37 degrees C in various media for histochemistry. For electron microscopic localization of enzymes a heavy metal capturing method had to be used. For light microscopy, the azo dye methods were frequently used, but these were not usable for electron microscopy. Alkaline phosphatase was found on the outer surface of osteoblast and hypertrophic cartilage cell membranes. The only intracellular enzyme activity was found on the mitochondrial membranes of the osteoclast and only when the pH of the media was lowered from the optimum 9.5 to 8.5. Alkaline phosphatase was not found along the osteocyte or young cartilage cell membranes...

Topics: Acid Phosphatase; Alkaline Phosphatase; Bone and Bones; Bone Neoplasms; Cartilage; Cartilage Diseases; Cell Membrane; Giant Cell Tumors; Golgi Apparatus; Histocytochemistry; Humans; Lysosomes; Mucolipidoses; Organoids; Osteoblasts; Osteoclasts; Osteocytes; Osteogenesis Imperfecta; Osteosarcoma; Phosphoric Monoester Hydrolases

Treatments to reduce fracture rates in adults with osteogenesis imperfecta are limited. Sclerostin antibody, developed for treating osteoporosis, has not been explored in adults with OI. This study demonstrates that treatment of adult OI mice respond favorably to sclerostin antibody therapy despite retention of the OI-causing defect.. Osteogenesis imperfecta (OI) is a heritable collagen-related bone dysplasia, characterized by brittle bones with increased fracture risk. Although OI fracture risk is greatest before puberty, adults with OI remain at risk of fracture. Antiresorptive bisphosphonates are commonly used to treat adult OI, but have shown mixed efficacy. New treatments which consistently improve bone mass throughout the skeleton may improve patient outcomes. Neutralizing antibodies to sclerostin (Scl-Ab) are a novel anabolic therapy that have shown efficacy in preclinical studies by stimulating bone formation via the canonical wnt signaling pathway. The purpose of this study was to evaluate Scl-Ab in an adult 6 month old Brtl/+ model of OI that harbors a typical heterozygous OI-causing Gly > Cys substitution on Col1a1.. Six-month-old WT and Brtl/+ mice were treated with Scl-Ab (25 mg/kg, 2×/week) or Veh for 5 weeks. OCN and TRACP5b serum assays, dynamic histomorphometry, microCT and mechanical testing were performed.. Adult Brtl/+ mice demonstrated a strong anabolic response to Scl-Ab with increased serum osteocalcin and bone formation rate. This anabolic response led to improved trabecular and cortical bone mass in the femur. Mechanical testing revealed Scl-Ab increased Brtl/+ femoral stiffness and strength.. Scl-Ab was successfully anabolic in an adult Brtl/+ model of OI.

Topics: Acid Phosphatase; Adaptor Proteins, Signal Transducing; Anabolic Agents; Animals; Antibodies, Neutralizing; Body Mass Index; Bone Density; Bone Morphogenetic Proteins; Disease Models, Animal; Drug Evaluation, Preclinical; Femur; Genetic Markers; Isoenzymes; Male; Mice, Mutant Strains; Osteocalcin; Osteogenesis; Osteogenesis Imperfecta; Stress, Mechanical; Tartrate-Resistant Acid Phosphatase; X-Ray Microtomography

Osteogenesis imperfecta (OI) is a genetic bone dysplasia characterized by osteopenia and easy susceptibility to fracture. Symptoms are most prominent during childhood. Although antiresorptive bisphosphonates have been widely used to treat pediatric OI, controlled trials show improved vertebral parameters but equivocal effects on long-bone fracture rates. New treatments for OI are needed to increase bone mass throughout the skeleton. Sclerostin antibody (Scl-Ab) therapy is potently anabolic in the skeleton by stimulating osteoblasts via the canonical wnt signaling pathway, and may be beneficial for treating OI. In this study, Scl-Ab therapy was investigated in mice heterozygous for a typical OI-causing Gly→Cys substitution in col1a1. Two weeks of Scl-Ab successfully stimulated osteoblast bone formation in a knock-in model for moderately severe OI (Brtl/+) and in WT mice, leading to improved bone mass and reduced long-bone fragility. Image-guided nanoindentation revealed no alteration in local tissue mineralization dynamics with Scl-Ab. These results contrast with previous findings of antiresorptive efficacy in OI both in mechanism and potency of effects on fragility. In conclusion, short-term Scl-Ab was successfully anabolic in osteoblasts harboring a typical OI-causing collagen mutation and represents a potential new therapy to improve bone mass and reduce fractures in pediatric OI.

Topics: Acid Phosphatase; Adaptor Proteins, Signal Transducing; Animals; Antibodies; Biomarkers; Biomechanical Phenomena; Body Weight; Calcification, Physiologic; Disease Models, Animal; Femur; Fluoresceins; Glycoproteins; Intercellular Signaling Peptides and Proteins; Isoenzymes; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Nanotechnology; Organ Size; Osteocalcin; Osteogenesis; Osteogenesis Imperfecta; Tartrate-Resistant Acid Phosphatase; X-Ray Microtomography

We report a direct comparison of receptor activator of nuclear factor kappa B ligand (RANKL) inhibition (RANK-Fc) with bisphosphonate treatment (alendronate, ALN) from infancy through early adulthood in a mouse model of osteogenesis imperfecta. Both ALN and RANK-Fc decreased fracture incidence to the same degree with increases in metaphyseal bone volume via increased number of thinner trabeculae.. The potential therapeutic benefit of RANKL inhibitors in osteogenesis imperfecta (OI) is under investigation. We report a direct comparison of RANKL inhibition (RANK-Fc) with bisphosphonate treatment (ALN) from infancy through early adulthood in a model of OI, the oim/oim mouse.. Two-week-old oim/oim, oim/+, and wildtype (+/+) mice were treated with RANK-Fc 1.5 mg/kg twice per week, ALN 0.21 mg/kg/week or saline (n = 12-20 per group) for 12 weeks.. ALN and RANK-Fc both decreased fracture incidence (9.0 ± 3.0 saline 4.4 ± 2.7 ALN, 4.3 ± 3.0 RANK-Fc fractures per mouse). Serum TRACP-5b activity decreased to 65% after 1 month in all treated mice, but increased sacrifice with RANK-Fc to 130-200% at sacrifice. Metaphyseal density was significantly increased with ALN in +/+ and oim/oim mice (p < 0.05) and tended to increase with RANK-Fc in +/+ mice. No changes in oim/oim femur biomechanical parameters occurred with treatment. Both ALN and RANK-Fc significantly increased trabecular number (3.73 ± 0.77 1/mm for oim/oim saline vs 7.93 ± 0.67 ALN and 7.34 ± 1.38 RANK-Fc) and decreased trabecular thickness (0.045 mm ± 0.003 for oim/oim saline vs 0.034 ± 0.003 ALN and 0.032 ± 0.002 RANK-Fc) and separation in all genotypes (0.28 ± 0.08 mm for oim/oim saline vs 0.12 ± 0.010 ALN and 13 ± 0.03 RANK-Fc)., with significant increase in bone volume fraction (BVF) with ALN, and a trend towards increased BVF in RANK-Fc.. Treatment of oim/oim mice with either a bisphosphonate or a RANK-Fc causes similar decreases in fracture incidence with increases in metaphyseal bone volume via increased number of thinner trabeculae.

Topics: Acid Phosphatase; Alendronate; Animals; Biomechanical Phenomena; Bone Density; Bone Density Conservation Agents; Disease Models, Animal; Drug Evaluation, Preclinical; Female; Isoenzymes; Male; Mice; Osteogenesis Imperfecta; Osteoporotic Fractures; RANK Ligand; Recombinant Fusion Proteins; Tartrate-Resistant Acid Phosphatase; Weight Gain; X-Ray Microtomography

Receptor activator of nuclear factor-κB ligand (RANKL) inhibitors are being considered for use in children with osteogenesis imperfecta (OI). We sought to assess efficacy of two doses of a RANKL inhibitor, osteoprotegerin-immunoglobulin Fc segment complex (OPG-Fc), in a growing animal model of OI, the col1α2-deficient mouse (oim/oim) and its wild-type controls (+/+).. Treated mice showed runting and radiographic evidence of osteopetrosis with either high- (20 mg/kg twice weekly) or low-dose (1 mg/kg/week) OPG-Fc. Because of this adverse event, OPG-Fc treatment was halted, and the mice were killed or monitored for recovery with monthly radiographs and assessment of serum osteoclast activity (tartrate-resistant acid phosphatase 5b, TRACP-5b) until 25 wk of age.. Twelve weeks of OPG-Fc treatment resulted in radiographic and histologic osteopetrosis with no evidence of bone modeling and negative tartrate-resistant acid phosphatase staining, root dentin abnormalities, and TRACP-5b activity suppression. Signs of recovery appeared 4-8 wk post-treatment.. Both high- and low-dose OPG-Fc treatment resulted in osteopetrotic changes in infant mice, an outcome that was not seen in studies with the RANKL inhibitor RANK-immunoglobulin Fc segment complex (RANK-Fc) or in studies with older animals. Further investigations of RANKL inhibitors are necessary before their consideration for use in children.

Topics: Acid Phosphatase; Age Factors; Animals; Biomarkers; Bone Remodeling; Collagen Type I; Dentin; Disease Models, Animal; Female; Immunoconjugates; Immunoglobulin Fc Fragments; Isoenzymes; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Osteoclasts; Osteogenesis Imperfecta; Osteopetrosis; Osteoprotegerin; Radiography; RANK Ligand; Risk Assessment; Tartrate-Resistant Acid Phosphatase; Time Factors; Tooth Eruption; Weight Gain

This study was carried out to evaluate the clinical validity and usefulness of serum tartrate-resistant fluoride-sensitive acid phosphatase (TrFsACP) activity using 2,6-dichloro-4-acetylphenyl phosphate as substrate at pH 6.2 in metabolic bone diseases. The mean Z-scores of TrFsACP activity in patients on hemodialysis were higher than in healthy subjects (male: 2.04+/-1.98, n = 49, P < .05; female: 1.49+/-2.43, n = 39, P < .05) and increased with duration of hemodialysis (r = .516, P < .01). Bone alkaline phosphatase also was found to be significantly higher in hemodialysis patients (male: 0.93+/-1.49, P < .05; female: 1.66+/-2.42, P < .05) compared with normal subjects: but had lower correlation with duration of hemodialysis than TrFsACP (r = .277, P < .05). Ulcerative colitis (1.37+/-2.21, n = 15) in males showed a significantly higher Z-score of TrFsACP compared with control subjects (P < .05). The relationship of TrFsACP activity and ultrasound findings (stiffness; speed of sound [SOS]; broadband ultra sound attenuation [BUA]) in healthy women aged 30-75 years (n = 95) were inversely and significantly correlated with stiffness (r = -.465, P < .01 ), SOS (r = -.484, P < .01), and BUA (r = -.366, P < .01), but were age dependent. TrFsACP activity significantly correlated with stiffness (r = -.521, P < .05) and SOS (r = -.527, P < .05) only in the age group of 46-55 years. BUA (r = -.313, P > .05) did not correlate significantly in any subject in the present study. We conclude that serum TrFsACP activity is useful in the diagnosis and monitoring of bone turnover.

Topics: Acid Phosphatase; Adult; Aged; Arthritis, Rheumatoid; Biomarkers; Bone and Bones; Bone Remodeling; Case-Control Studies; Colitis, Ulcerative; Female; Fluorides; Humans; Male; Middle Aged; Osteogenesis Imperfecta; Osteoporosis; Predictive Value of Tests; Reference Values; Renal Dialysis; Tartrates; Ultrasonography

We measured serum levels of total alkaline phosphatase activity, osteocalcin, carboxy-terminal propeptide of human type I procollagen (PICP), tartrate-resistant acid phosphatase activity (TRAP), and the fasting urinary hydroxyproline/creatinine ratio (OHPr/Cr) in seven affected members (four men, three women; age, 43.3 +/- 16.6 years [mean +/- SD]) of a family with clinically diagnosed type I-A osteogenesis imperfecta (OI) and in eight (five men, three women) normal age-matched (38.2 +/- 10.3) relatives. Three boys with OI and three normal girls of the same family were also studied, although they were excluded from statistical analysis. Bone mineral density was also determined at four different skeletal sites. Serum levels of PICP were measured with a radioimmunoassay (Farmos Diagnostica, Turku, Finland). There were no significant differences in mean values of the biomarkers studied between OI patients and normal relatives, with the only exception being serum levels of PICP (35 +/- 7.5 v 219 +/- 107.5 micrograms/L, P < .001). A significant reduction of BMD was found in OI patients compared with normal relatives at the lumbar (L) spine (680 +/- 61 v 1,128 +/- 92 mg/cm2, P < .001), at the ultradistal radius ([UDR] 323 +/- 85 v 458 +/- 76, P < .006), at the femoral neck ([F] 494 +/- 140 v 791 +/- 104, P < .001), and at the junction of the distal and middle third of the radius ([MR] 639 +/- 71 v 717 +/- 52, P < .029).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Acid Phosphatase; Adolescent; Adult; Aged; Alkaline Phosphatase; Biomarkers; Bone Density; Bone Resorption; Child; Child, Preschool; Creatinine; Densitometry; Female; Humans; Hydroxyproline; Male; Middle Aged; Osteocalcin; Osteogenesis Imperfecta; Pedigree; Peptide Fragments; Phenotype; Procollagen

Serum tartrate-resistant acid phosphatase (TRAP) and total body bone mineral content (TBBM) were determined in a group of 16 children with osteogenesis imperfecta (OI) aged 5-14 years, 9 of whom suffered from type I and 7 from type III OI. TRAP and TBBM were also determined in a group of 26 normal children of a similar age range. TRAP levels were reduced in the type I and III OI groups (p less than 0.001). TBBM levels were lower in type I OI than in type III (p less than 0.005), and both OI groups showed reduced levels compared to the controls (p less than 0.001). The control group subjects showed a significant correlation between TRAP and TBBM (r = -0.62; p less than 0.001) which was not observed in the OI groups. Since TRAP is a biological marker of bone turnover, the results suggest that bone turnover is reduced in OI.

Topics: Absorptiometry, Photon; Acid Phosphatase; Adolescent; Bone Density; Child; Child, Preschool; Female; Humans; Male; Osteogenesis Imperfecta; Tartrates

10 children with osteogenesis imperfecta, 4 with "tarda" and 6 with "congenita" varieties of the disease, were treated with salmon calcitonin (SCT) for intervals ranging from 14 to 35 months. Responses to SCT therapy in patients with osteogenesis imperfecta tarda were characterized by an apparent decreased fracture incidence in three, a fall in either alkaline or acid phosphatase, and a rate of increase in forearm bone mass which was greater than that observed in an untreated "tarda" population. The chemical response SCT therapy varied in children with osteogenesis imperfecta congenita, only one demonstrating a decrease in both acid phosphatase and urinary hydroxyproline. Three others responded with a rise in acid phosphatase, two of whom also demonstrated a fall in urinary hydroxyproline; in two other "congenita" patients urinary hydroxyproline was actually higher after SCT treatment and acid phosphatase relatively unchanged. Alkaline phosphatase was normal in all "congenita" patients before and following the SCT treatment interval. These varied biochemical responses were associated with temporary increments in bone mass early in the treatment course, although in bone mass early in the treatment course, although one "congenita" patient with the largest calciuric response to SCT and an increase in hydroxyproline excretion demonstrated progressive increments in skeletal mineral content during a 14-month treatment interval. In both "tarda" and "congenita" subjects, parathyroid hormone was unchanged by chronic SCT treatment; SCT-antibodies were detectable although biological responsivity to SCT persisted.

Topics: Acid Phosphatase; Age Factors; Alkaline Phosphatase; Animals; Calcitonin; Calcium; Child; Child, Preschool; Diet Therapy; Female; Follow-Up Studies; Humans; Hydroxyproline; Infant; Male; Osteogenesis Imperfecta; Parathyroid Hormone; Phosphates; Salmon

Topics: Acid Phosphatase; Adolescent; Adult; Alkaline Phosphatase; Alpha-Globulins; Child; Female; Fractures, Bone; Humans; Male; Middle Aged; Osteogenesis Imperfecta

Topics: Acid Phosphatase; Adult; Alkaline Phosphatase; Blood Urea Nitrogen; Calcium; Child; Fluorides; Fractures, Spontaneous; Humans; Magnesium; Nitrogen; Osteogenesis Imperfecta; Phosphorus; Potassium

Topics: Acid Phosphatase; Alkaline Phosphatase; Bone and Bones; Bone Matrix; Bone Resorption; Calcium Phosphates; Child; Glycogen; Golgi Apparatus; Histocytochemistry; Humans; Ilium; Microscopy, Electron; Osteoblasts; Osteogenesis; Osteogenesis Imperfecta

Topics: Acid Phosphatase; Adolescent; Adult; Ascorbic Acid; Blood Protein Electrophoresis; Carotenoids; Child; Child, Preschool; Female; Glycoproteins; Humans; Immunoelectrophoresis; Male; Middle Aged; Osteogenesis Imperfecta; Oxalates; Vitamin A

Topics: Acid Phosphatase; Bone Diseases; Bone Neoplasms; Clinical Enzyme Tests; Diagnosis, Differential; Gaucher Disease; Humans; Hyperparathyroidism; Male; Osteitis Deformans; Osteitis Fibrosa Cystica; Osteogenesis Imperfecta; Osteopetrosis; Osteosclerosis; Prostatic Neoplasms

Topics: Acid Phosphatase; Humans; Osteogenesis Imperfecta; Phosphoric Monoester Hydrolases

Topics: Acid Phosphatase; Humans; Osteogenesis Imperfecta; Phosphoric Monoester Hydrolases

Topics: Acid Phosphatase; Humans; Osteogenesis Imperfecta; Phosphoric Monoester Hydrolases