acid-phosphatase and Femoral-Fractures

Osteoporosis is characterized by poor bone quality. However, it is still controversially discussed whether osteoporosis compromises fracture healing. Herein, we studied whether the course of healing of a femur fracture is affected by osteoporosis or age.. Using the senescence-accelerated osteoporotic mouse, strain P6 (SAMP6), and a closed femur fracture model, we studied the process of fracture healing in 5- and 10-month-old animals, including biomechanical, histomorphometric, and protein biochemical analysis.. In five-month-old osteoporotic SAMP6 mice, bending stiffness, callus size, and callus tissue distribution as well as the concentrations of the bone formation marker osteocalcin and the bone resorption markers tartrate-resistant acid phosphatase form 5b (TRAP) and deoxypyridinoline (DPD) did not differ from that of non-osteoporotic, senescence-resistant, strain 1 (SAMR1) controls. In contrast, femur fractures in 10-month-old SAMP6 mice showed a significantly reduced bending stiffness and an increased callus size compared to fractures in age-matched SAMR1 controls. This indicates a delayed fracture healing in advanced age SAMP6 mice. The delay of fracture healing was associated with higher concentrations of TRAP and DPD. Significant differences in osteocalcin concentrations were not found between SAMP6 animals and SAMR1 controls.. In conclusion, the present study indicates that fracture healing in osteoporotic SAMP6 mice is not affected in five-month-old animals, but delayed in animals with an age of 10 months. This is most probably due to the increased osteoclast activity in advanced age SAMP6 animals.

Topics: Acid Phosphatase; Aging; Amino Acids; Animals; Bone Resorption; Femoral Fractures; Fracture Healing; Fractures, Closed; Isoenzymes; Mice; Mice, Mutant Strains; Osteocalcin; Osteoclasts; Osteoporosis; Tartrate-Resistant Acid Phosphatase; Weight-Bearing

As a downstream product of cyclooxygenase 2 (COX-2), prostaglandin E(2) (PGE(2)) plays a crucial role in the regulation of bone formation. It has four different receptor subtypes (EP1 through EP4), each of which exerts different effects in bone. EP2 and EP4 induce bone formation through the protein kinase A (PKA) pathway, whereas EP3 inhibits bone formation in vitro. However, the effect of EP1 receptor signaling during bone formation remains unclear. Closed, stabilized femoral fractures were created in mice with EP1 receptor loss of function at 10 weeks of age. Healing was evaluated by radiographic imaging, histology, gene expression studies, micro-computed tomographic (µCT), and biomechanical measures. EP1(-/-) mouse fractures have increased formation of cartilage, increased fracture callus, and more rapid completion of endochondral ossification. The fractures heal faster and with earlier fracture callus mineralization with an altered expression of genes involved in bone repair and remodeling. Fractures in EP1(-/-) mice also had an earlier appearance of tartrate-resistant acid phosphatase (TRAcP)-positive osteoclasts, accelerated bone remodeling, and an earlier return to normal bone morphometry. EP1(-/-) mesenchymal progenitor cells isolated from bone marrow have higher osteoblast differentiation capacity and accelerated bone nodule formation and mineralization in vitro. Loss of the EP1 receptor did not affect EP2 or EP4 signaling, suggesting that EP1 and its downstream signaling targets directly regulate fracture healing. We show that unlike the PGE(2) receptors EP2 and EP4, the EP1 receptor is a negative regulator that acts at multiple stages of the fracture healing process. Inhibition of EP1 signaling is a potential means to enhance fracture healing.

Topics: Acid Phosphatase; Alkaline Phosphatase; Animals; Bone Density; Bony Callus; Cartilage; Cell Differentiation; Cells, Cultured; Collagen Type I; Collagen Type I, alpha 1 Chain; Collagen Type II; Collagen Type X; Core Binding Factor Alpha 1 Subunit; Female; Femoral Fractures; Fracture Healing; Gene Expression; Isoenzymes; Male; Mesenchymal Stem Cells; Mice; Mice, Inbred C57BL; Mice, Knockout; Osteoblasts; Osteocalcin; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptors, Prostaglandin E, EP1 Subtype; Receptors, Prostaglandin E, EP2 Subtype; Receptors, Prostaglandin E, EP4 Subtype; Sp7 Transcription Factor; Tartrate-Resistant Acid Phosphatase; Time Factors; Torsion, Mechanical; Transcription Factors; X-Ray Microtomography

A new small animal model of bone atrophic nonunion was established for investigating the process of bone regeneration by performing cauterization of the periosteum, removal of the local bone marrow, and stabilization with external fixation. The model allows the creation of an atrophic nonunion without the need for a critical size defect. Furthermore, it provides reproducible, well-defined mechanical conditions and minimized physical interference of the implant with the biological processes in the healing zone. Eighty adult Sprague-Dawley rats received an osteotomy of the left femur, stabilized with an external fixator. In half of the animals, the periosteum proximal and distal to the osteotomy was destroyed by cauterization and the adjacent bone marrow was removed (nonunion group). At 2 and 8 weeks after surgery, radiological, biomechanical, histological, and histomorphometrical analyses showed a typical physiological healing in the control group, while the nonunion group was characterized by resorption of the bone ends with some callus formation distant to the osteotomy. At both time points, the callus was composed of significantly less bone and significantly more connective tissue (p < 0.001). In addition, the torsional strength of the osteotomized femur was significantly less in the nonunion group than in the control group, which was comparable to that of the intact femur (p < 0.001). In conclusion, the present model allows the induction of an atrophic nonunion without the need of a critical size defect. It is reproducible, provides standardized biomechanical conditions, and allows minimized interaction of the implant with the healing zone.

Topics: Acid Phosphatase; Animals; Atrophy; Biomechanical Phenomena; Cautery; External Fixators; Femoral Fractures; Femur; Fracture Fixation; Fracture Healing; Fractures, Malunited; Isoenzymes; Male; Models, Animal; Osteoclasts; Osteotomy; Postoperative Care; Radiography; Rats; Rats, Sprague-Dawley; Tartrate-Resistant Acid Phosphatase

Because osteoporotic patients are prone to fractures, it must be considered whether or not patients undergoing drug therapies should discontinue treatment after sustaining a non-vertebral fracture. This study has tested the effect of novel active vitamin D3 analog, 1alpha,25-dihydroxy-2beta(3-hydroxypropoxy)vitamin D3 (ED-71), on the fracture healing comparing with a powerful anti-resorptive agent, alendronate, using a rat femoral fracture model.. Female SD rats (n=201) allocated into 6 groups were treated with MCT-vehicle and ED-71 at 0.025 and 0.05 microg/kg/day (EDL and EDH groups), and with saline-vehicle and alendronate at 5 and 10 microg/kg/day (ALL and ALH groups). After 4 weeks of pretreatment, osteotomy of the femur was performed. Treatment was continued until sacrifice at 6 and 16 weeks post-fracture. Fracture callus was evaluated by soft X-ray radiography, pQCT, biomechanical testing and histomorphometry.. At 16 weeks post-fracture, new cortical shell appeared in 100% of Control (MCT and saline-vehicle), EDL and EHL, and in 67% and 56% of ALL and ALH, respectively. ED-71 treatment showed insignificantly large callus area only at 6 weeks, while alendronate treatment induced bigger callus at both 6 and 16 weeks post-fracture. The lamellar/callus area was decreased only at 6 weeks by ED-71 treatment, but both at 6 and 16 weeks by alendronate treatment. Osteoclast number in callus surface was decreased in both ED-71 and alendronate treatment groups at 6 weeks and in EDH, ALL and ALH at 16 weeks, indicating that ED-71 inhibits osteoclastic bone resorption, but its effect is less prominent than alendronate. Almost complete callus remodeling was observed in ED-71-treated groups at 16 weeks without any significant change in structural and material properties of fractured bone.. ED-71 suppression of callus remodeling by inhibiting osteoclastic bone resorption was mild and dose-dependent and did not interfere with natural fracture healing process at 16 weeks post-fracture.

Topics: Acid Phosphatase; Animals; Bone Remodeling; Bony Callus; Calcitriol; Disease Models, Animal; Female; Femoral Fractures; Femur; Fracture Healing; Isoenzymes; Radiography; Rats; Rats, Sprague-Dawley; Tartrate-Resistant Acid Phosphatase; Vitamin D

The osteoprotegerin (OPG)/receptor activator of nuclear factor-kappaB ligand (RANKL)/receptor activator of nuclear factor-kappaB (RANK) system was evaluated as a potential target of CGRP anabolic activity on bone. Primary cultures of human osteoblast-like cells (hOB) express calcitonin receptor-like receptor (CLR) and receptor activity modifying protein 1, and, because CGRP stimulates cAMP (one of the modulators of OPG production in osteoblasts), it was investigated whether it affects OPG secretion and expression in hOB. CGRP treatment of hOB (10(-11) M-10(-7) M) dose-dependently inhibited OPG secretion with an EC(50) of 1.08 x 10(-10) M, and also decreased its expression. This action was blocked by the antagonist CGRP(8-37). Forskolin, a stimulator of cAMP production, and dibutyryl cAMP also reduced the production of OPG. CGRP (10(-8) M) enhanced protein kinase A (PKA) activity in hOB, and hOB exposure to the PKA inhibitor, H89 (2 x 10(-6) M), abolished the inhibitory effect of CGRP on OPG secretion. Conditioned media from CGRP-treated hOB increased the number of multinucleated tartrate-resistant acid phosphatase-positive cells and the secretion of cathepsin K in human peripheral blood mononuclear cells compared with the conditioned media of untreated hOB. These results show that the cAMP/PKA pathway is involved in the CGRP inhibition of OPG mRNA and protein secretion in hOB and that this effect favors osteoclastogenesis. CGRP could thus modulate the balance between osteoblast and osteoclast activity, participating in the fine tuning of all of the bone remodeling phases necessary for the subsequent anabolic effect.

Topics: Acid Phosphatase; Aged; Bone Remodeling; Calcitonin Gene-Related Peptide; Calcitonin Gene-Related Peptide Receptor Antagonists; Carrier Proteins; Cathepsin K; Cathepsins; Cell Separation; Colforsin; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Femoral Fractures; Glycoproteins; Humans; Isoenzymes; Leukocytes, Mononuclear; Membrane Glycoproteins; Middle Aged; Osteoblasts; Osteoclasts; Osteoprotegerin; Peptide Fragments; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Calcitonin Gene-Related Peptide; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Signal Transduction; Tartrate-Resistant Acid Phosphatase

The effect of zinc acexamate on fracture healing of the femoral-diaphyseal tissues in rats was investigated in vivo. Zinc acexamate (0.3 and 10.0 mg Zn/100 g body weight per day) was orally administered to rats (4 weeks old) surgically fractured the femoral diaphysis for 14 to 28 days. Calcium content and alkaline phosphatase activity in the femoral-diaphyseal tissues were significantly decreased in rats with fracture healing, while bone acid phosphatase activity and protein content were markedly increased. The administration of zinc acexamate (10.0 mg Zn/100 g) for 28 days caused a significant increase in calcium content, alkaline and acid phosphatases activities, protein and deoxyribonucleic acid (DNA) contents in the femoral-diaphyseal tissues of rats with fracture healing. With the lower dose (3.0 mg Zn/100 g), zinc compound had a partial effect on bone components. Femoral mineral density in rats with fracture healing was significantly increased by the administration of zinc acexamate (10.0 mg Zn/100 g) for 28 days. Femoral-diaphyseal zinc content was significantly decreased in rats with fracture healing. This decrease was completely restored by the administration of zinc acexamate (10.0 mg Zn/100 g) for 28 days. The present study suggests that the supplement of zinc compound stimulates fracture healing of the femoral-diaphyseal tissues in rats.

Topics: Acid Phosphatase; Alkaline Phosphatase; Aminocaproates; Aminocaproic Acid; Animals; Antifibrinolytic Agents; Calcium; Femoral Fractures; Femur; Fracture Healing; Male; Proteins; Rats; Rats, Wistar; Zinc

Quantitative microchemical study of the tissues comprising fracture callus has been undertaken to correlate the biochemical activity of the bone repair process with its previously established morphological features. Areas of proliferating fibrous tissue, hypertrophic cartilage, new bone and undifferentiated granulation tissue were analyzed for their content of carbohydrate metabolizing and phosphatase enzymes. Fracture callus cartilage is biochemically similar to epiphyseal cartilage. Carbohydrate metabolism provides structural intermediates and energy for bone repair. Inorganic pyrophosphatase removes the inorganic pyrophosphate which accumulates from structural synthesis and prevents its inhibition of new bone calcification. The individual parts of the callus have identical biochemical function regardless of the age or healing time of the fracture callus.

Topics: Acid Phosphatase; Alkaline Phosphatase; Animals; Bone Development; Bony Callus; Carbohydrate Metabolism; Femoral Fractures; Glucose; Glucosephosphate Dehydrogenase; Granulation Tissue; Hexokinase; Hydroxyproline; Isocitrate Dehydrogenase; L-Lactate Dehydrogenase; Malate Dehydrogenase; Male; Phosphates; Pyrophosphatases; Rabbits

Topics: Acid Phosphatase; Animals; Bone Regeneration; Bony Callus; Cathepsins; Decalcification Technique; Edetic Acid; Female; Femoral Fractures; Glucuronidase; Histocytochemistry; Lysosomes; Macrophages; Nitrophenols; Osteoblasts; Osteogenesis; Rats; Sulfatases; Sulfates; Thorium Dioxide; Time Factors

A five-year-old boy presented with a three-and-a-half-year history of repeated bone fractures and progressive bone deformity. The excretion of hydroxyproline in the urine was greatly increased, and serum alkaline phosphatase and acid phosphatase levels were very high. These abnormalities together with the findings on bone histology and radiology suggested a diagnosis of juvenile Paget's disease. Human calcitonin reduced the bone turnover as evidenced by an immediate and sustained fall in urine hydroxyproline excretion, while calcium and phosphate balance became more positive. This treatment is therefore being continued on an outpatient basis.

Topics: Acid Phosphatase; Alkaline Phosphatase; Bone and Bones; Calcitonin; Calcium; Child, Preschool; Femoral Fractures; Humans; Hydroxyproline; Hyperostosis, Cortical, Congenital; Leg; Male; Phosphates; Radiography

Topics: Acid Phosphatase; Alkaline Phosphatase; Animals; Electrophoresis; Female; Femoral Fractures; Fractures, Ununited; Isoenzymes; L-Lactate Dehydrogenase; Rats; Spectrophotometry

Topics: Acid Phosphatase; Animals; Autoradiography; Blood Cell Count; Blood Platelets; Carbon Dioxide; Carbon Isotopes; Contusions; Femoral Fractures; Glucuronidase; Hematocrit; Hydrogen-Ion Concentration; Microcirculation; Oxygen; Papio; Pulmonary Embolism; Serotonin; Thigh