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Rat tibiae bone response to atherogenic diet
Abstracts Parathyroid hormone-related peptide (PTHrP, also known as its tumoral analog) was initially identified through its role in humoral hypercalcemia of malignancy, one of the most frequent paraneoplastic syndromes. Recently, the protein was found to be distributed in most fetal and adult tissues. It has been observed that their expression correlates with the severity of colon carcinoma and that its overexpression increases cell proliferation in certain intestinal cell lines. However, so far the role of PTHrP in Caco-2, a cell line derived from human colorectal adenocarcinoma, is not known. This study examined, for the first time, whether PTHrP induces proliferation of Caco-2 cells and whether it regulates the MAP kinases (ERK1/2, JNK1/2, p38 MAPK) signaling related to events of cell proliferation. Using different cell proliferation assays we found that PTHrP (10− 8 M) increased cell proliferation compared to the control and, in a time dependent manner, being maximal response at 5 and 6 days of treatment. Furthermore, analysis by Western blot revealed that PTHrP (1–48 h) induced phosphorylation and activation of ERK 1/2 and increased the levels of c-Myc protein, a transcription factor that regulates genes involved in cell proliferation. However, at the times studied, no significant changes were observed in the phosphorylation of JNK isoforms or in the protein expression of both the α isoform of p38 and ERK 1/2. Moreover, immunocytochemistry assays revealed that PTHrP induces the subcellular redistribution of the ERKs. Furthermore, a specific inhibitor of MEK, the kinase “upstream” of ERK 1/2, decreased PTHrP-induced increased of viable cells. These results suggest that in Caco-2 intestinal cells PTHrP promotes the activation and subcellular redistribution of ERK 1/2, increases the expression of c-Myc and the proliferation of intestinal cells through the signaling pathway of ERK 1/2.
doi:10.1016/j.bone.2012.12.035
Positive effects of olpadronate (OPD) on rat femur structural design, toughness and strength, unrelated to tissue mineralization and stiffness R. Capozza, N. Mondelo, P. Reina, L. Nocciolino, J.L. Ferretti, G. Cointry National University of Rosario & Gador SA, Buenos Aires, Argentina Fracture prevention by bisphosphonates (BPs) cannot be fully explained by their effects on remodeling and crystallinity. A positive interaction with the modulation/ orientation of modeling drifts by bone mechanostat by preventing osteocyte/ osteoblast apoptosis (already shown in vitro) and a derived improvement of bone toughness can be proposed; but this can only be shown by studying all the diaphyseal design, stiffness, toughness and strength of geometrically regular and only-modeling bones. With that purpose, 28 3-month-old male rats received high oral doses (45 or 90 mg/kg /d) of OPD, and their femur diaphyses were pQCT-scanned and tested in bending. Compared to 8 untreated controls, both OPD doses enhanced significantly 1. cortical bone area (+ 21%) and bending and torsion moments of inertia (+ 30, + 31%), 2. yield structural stiffness and strength (+15%, +13%), and 3. structural toughness (energy absorption and ultimate strain, +126%, +32%), further than needed for bwbearing. Ultimate strength increased (+ 29%) in correlation with the improvements in diaphyseal design and toughness (p b 0.001), but not so with tissue mineralization (cortical vBMD) and stiffness (calculated E) which were unaffected. The observed geometric/structural improvements unrelated to mineralization and remodeling in this model can only reflect a positive interaction with the directional modulation of modeling drifts by bone mechanostat, congruent with the anti-apoptotic effects of OPD. In remodeling bones, this could complement the unpredictable mechanical impact of the modest bone mass increase induced by BPs, and even neutralize the structural toughness impairment (inductor of diaphyseal fractures) because of reduced turnover and crystallinity.
doi:10.1016/j.bone.2012.12.036
Rapid bone mass recovery after parathyroidectomy, in a 15-year-old boy with parathroid adenomas G. Viterboa, C. Taua, V. Ayarzabalb, L. Felipec, A. Belgoroskya a Metabolismo cálcico y óseo, Endocrinología b Cirugía c Medicina Nuclear, Hospital de Pediatría J.P.Garrahan, Buenos Aires, Argentina Primary hyperparathyroidism is extremely rare in childhood and adolescence. Here we report a clinical case of a 15-year-3-month-old boy who began 2 years before with pain in his knees, genu valgum, and fatigue. Physical examination showed severe genu valgum. Biochemical tests showed hypercalcemia (12.2 mg/dl), hypophosphatemia (2.3 mg/ dl), hypercalciuria (6.4 mg/kg/day), high alkaline phosphatase (2812 IU/L), low 25-hydroxyvitamin D (6 ng/ml), and hyperparathyroidism (PTH: 2653 pg/ml, normal value 12–72). Skull, hands, and knees x-rays showed subperiosteal resorption, rickets, and osteomalacia respectively. Kidney ultrasonography showed increased
603
echogenicity on both sides. Neck ultrasonography and technesium-99 m Sestamibi revealed parathyroid adenomas. Spine, femora, and whole body bone densitometry disclosed markedly reduced bone mineral density: L2–L4: 0.87 g/cm2, Z-score: − 2.3, right femur 0.67 g/cm2, left femur 0.76 g/cm2, and whole body 0.82 g/cm2, Z-score: − 3.4. Two parathyroid adenomas situated on the upper and lower part of the right lobe of the thyroid gland were successfully removed. He developed severe hungry bone syndrome 96 h after surgery. Bone densitometry, repeated after four months, showed a dramatic increase of bone mineral density with normalization in all sites: spine: L2–L4: 1.192 g/cm2, Z-score: + 0.7; right femur: 1.097 g/cm2, left femur: 1.088 g/cm2, whole body: 1.065 g/cm2, z-score + 0.4. In conclusion: Here, we report a case of primary hyperparathyroidism due to parathyroid adenomas in an adolescent boy. He developed severe hungry bone syndrome after surgery. Follow-up and outcome were good and four months after surgery he had completely recovered bone mass.
doi:10.1016/j.bone.2012.12.037
Rat tibiae bone response to atherogenic diet F. Nuñeza, M.J. Gubertc, P. Gómez Echarrenb, P. Rodríguezb, S.M. Friedmanb, C.A. Gambaa,b a Department of Histology, University of Buenos Aires, Argentina b Department of Biochemistry, Faculty of Dentistry, University of Buenos Aires, Argentina c Degree of Bioimages Production, Faculty of Medicine, University of Buenos Aires, Argentina In previous studies we have focused our attention on the mandible. In the present study we speculate that bone modeling of rat tibiae could be altered by atherogenic diet intake. Male weanling Wistar rats (n = 12), divided by weight (Wt) into: Control (C) and experimental (E). C received rodent stock diet (pellets) & E, atherogenic diet (pellets + saturated fatty acids + cholesterol) for 7 weeks (7w), monitoring anthropometry and diet intake. At 7w, blood (mg/dl) lipid-lipoprotein atherogenic profile: total cholesterol (T-cho), triglycerides (TG), high density lipoprotein-cholesterol (HDLcho), HDL-non-cholesterol (n-HDL-cho), confirmed that diet was atherogenc. On the left tibiae the following were measured (Vernier ± 1:20 mm): dry weight (DWt), length (L), epyphiseal height (Eh) & width (Ew), and diaphyseal width (Dw). Right tibiae were fixed in buffered formalin-PBS10%, decalcified in EDTA(pH 7.2), embedded in paraffin for transverse oriented sections of the central diaphysis–standarized-, stained with hematoxiline-eosine, allowed measurement of: total transverse (Tt) and cortical (C1 & C2) sections (μm). Statistics: Student's t test. Results (mean ± SD) at 7w: no anthropometric nor intake differences (p N 0.05), E showed a greater Dw (2.71 ± 0.12 vs 2.59 ± 0.03 mm; p = 0.039) that was confirmed with histolological Tt (2271 ± 95 vs 2045 ± 132 μm; p = 0.041). The remaining measurements did not show significant differences. These results suggest that an atherogenic diet would influence in the final shape of the tibiae, indicating that bone modeling could be altered by a high intake of saturated fatty acids and cholesterol when there is no anthropometric evidence. Clinically this could account for a more vulnerable bone.
doi:10.1016/j.bone.2012.12.038
The intestinal calcium absorption inhibition in diabetes mellitus occurs with alteration in the antioxidant system V.A. Rodríguez, M.E. Peralta López, M.A. Rivoira, N.G. Tolosa de Talamoni Laboratorio de Metabolismo Fosfocálcico “Dr.Cañas”, Cát. de Bioq. y Biol. Mol., Fac. de Cs. Médicas, Universidad Nacional de Córdoba, Argentina Previous studies of our laboratory demonstrated that duodenal oxidative stress is associated with a reduction of intestinal calcium absorption. The aim of this work was to analyze the duodenal antioxidant system in an experimental model of DM. Twomonth old male Wistar rats were divided into two groups: a) controls and b) treated with streptozotocin (single intraperitoneal injection of 60 mg/kg body weight in 100 mM citrate buffer pH 4.5) after a 12-hour fast. Glucose in serum and urine was determined before the induction as well as after 5 days, 1 and 2 months. Rats with glycemia over 250 mg/dl were considered diabetic. Calcium, phosphorus and glycosilated hemoglobin were measured. Total glutathione (GSH), the activity of alkaline phosphatase (AP) and antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)) were determined in duodenal mucosa by spectrophotometry. Controls and diabetic rats had similar levels of calcium and phosphorus in serum. AP activity was significantly lower in diabetic rats than in 5 days and 1 month controls after the induction while it was higher 2 months after streptozotocin injection. Total GSH content decreased in diabetic rats as compared with controls at the studied times. SOD activity did not change whereas CAT activity increased in diabetic rats
doi:10.1016/j.bone.2012.12.035
Positive effects of olpadronate (OPD) on rat femur structural design, toughness and strength, unrelated to tissue mineralization and stiffness R. Capozza, N. Mondelo, P. Reina, L. Nocciolino, J.L. Ferretti, G. Cointry National University of Rosario & Gador SA, Buenos Aires, Argentina Fracture prevention by bisphosphonates (BPs) cannot be fully explained by their effects on remodeling and crystallinity. A positive interaction with the modulation/ orientation of modeling drifts by bone mechanostat by preventing osteocyte/ osteoblast apoptosis (already shown in vitro) and a derived improvement of bone toughness can be proposed; but this can only be shown by studying all the diaphyseal design, stiffness, toughness and strength of geometrically regular and only-modeling bones. With that purpose, 28 3-month-old male rats received high oral doses (45 or 90 mg/kg /d) of OPD, and their femur diaphyses were pQCT-scanned and tested in bending. Compared to 8 untreated controls, both OPD doses enhanced significantly 1. cortical bone area (+ 21%) and bending and torsion moments of inertia (+ 30, + 31%), 2. yield structural stiffness and strength (+15%, +13%), and 3. structural toughness (energy absorption and ultimate strain, +126%, +32%), further than needed for bwbearing. Ultimate strength increased (+ 29%) in correlation with the improvements in diaphyseal design and toughness (p b 0.001), but not so with tissue mineralization (cortical vBMD) and stiffness (calculated E) which were unaffected. The observed geometric/structural improvements unrelated to mineralization and remodeling in this model can only reflect a positive interaction with the directional modulation of modeling drifts by bone mechanostat, congruent with the anti-apoptotic effects of OPD. In remodeling bones, this could complement the unpredictable mechanical impact of the modest bone mass increase induced by BPs, and even neutralize the structural toughness impairment (inductor of diaphyseal fractures) because of reduced turnover and crystallinity.
doi:10.1016/j.bone.2012.12.036
Rapid bone mass recovery after parathyroidectomy, in a 15-year-old boy with parathroid adenomas G. Viterboa, C. Taua, V. Ayarzabalb, L. Felipec, A. Belgoroskya a Metabolismo cálcico y óseo, Endocrinología b Cirugía c Medicina Nuclear, Hospital de Pediatría J.P.Garrahan, Buenos Aires, Argentina Primary hyperparathyroidism is extremely rare in childhood and adolescence. Here we report a clinical case of a 15-year-3-month-old boy who began 2 years before with pain in his knees, genu valgum, and fatigue. Physical examination showed severe genu valgum. Biochemical tests showed hypercalcemia (12.2 mg/dl), hypophosphatemia (2.3 mg/ dl), hypercalciuria (6.4 mg/kg/day), high alkaline phosphatase (2812 IU/L), low 25-hydroxyvitamin D (6 ng/ml), and hyperparathyroidism (PTH: 2653 pg/ml, normal value 12–72). Skull, hands, and knees x-rays showed subperiosteal resorption, rickets, and osteomalacia respectively. Kidney ultrasonography showed increased
603
echogenicity on both sides. Neck ultrasonography and technesium-99 m Sestamibi revealed parathyroid adenomas. Spine, femora, and whole body bone densitometry disclosed markedly reduced bone mineral density: L2–L4: 0.87 g/cm2, Z-score: − 2.3, right femur 0.67 g/cm2, left femur 0.76 g/cm2, and whole body 0.82 g/cm2, Z-score: − 3.4. Two parathyroid adenomas situated on the upper and lower part of the right lobe of the thyroid gland were successfully removed. He developed severe hungry bone syndrome 96 h after surgery. Bone densitometry, repeated after four months, showed a dramatic increase of bone mineral density with normalization in all sites: spine: L2–L4: 1.192 g/cm2, Z-score: + 0.7; right femur: 1.097 g/cm2, left femur: 1.088 g/cm2, whole body: 1.065 g/cm2, z-score + 0.4. In conclusion: Here, we report a case of primary hyperparathyroidism due to parathyroid adenomas in an adolescent boy. He developed severe hungry bone syndrome after surgery. Follow-up and outcome were good and four months after surgery he had completely recovered bone mass.
doi:10.1016/j.bone.2012.12.037
Rat tibiae bone response to atherogenic diet F. Nuñeza, M.J. Gubertc, P. Gómez Echarrenb, P. Rodríguezb, S.M. Friedmanb, C.A. Gambaa,b a Department of Histology, University of Buenos Aires, Argentina b Department of Biochemistry, Faculty of Dentistry, University of Buenos Aires, Argentina c Degree of Bioimages Production, Faculty of Medicine, University of Buenos Aires, Argentina In previous studies we have focused our attention on the mandible. In the present study we speculate that bone modeling of rat tibiae could be altered by atherogenic diet intake. Male weanling Wistar rats (n = 12), divided by weight (Wt) into: Control (C) and experimental (E). C received rodent stock diet (pellets) & E, atherogenic diet (pellets + saturated fatty acids + cholesterol) for 7 weeks (7w), monitoring anthropometry and diet intake. At 7w, blood (mg/dl) lipid-lipoprotein atherogenic profile: total cholesterol (T-cho), triglycerides (TG), high density lipoprotein-cholesterol (HDLcho), HDL-non-cholesterol (n-HDL-cho), confirmed that diet was atherogenc. On the left tibiae the following were measured (Vernier ± 1:20 mm): dry weight (DWt), length (L), epyphiseal height (Eh) & width (Ew), and diaphyseal width (Dw). Right tibiae were fixed in buffered formalin-PBS10%, decalcified in EDTA(pH 7.2), embedded in paraffin for transverse oriented sections of the central diaphysis–standarized-, stained with hematoxiline-eosine, allowed measurement of: total transverse (Tt) and cortical (C1 & C2) sections (μm). Statistics: Student's t test. Results (mean ± SD) at 7w: no anthropometric nor intake differences (p N 0.05), E showed a greater Dw (2.71 ± 0.12 vs 2.59 ± 0.03 mm; p = 0.039) that was confirmed with histolological Tt (2271 ± 95 vs 2045 ± 132 μm; p = 0.041). The remaining measurements did not show significant differences. These results suggest that an atherogenic diet would influence in the final shape of the tibiae, indicating that bone modeling could be altered by a high intake of saturated fatty acids and cholesterol when there is no anthropometric evidence. Clinically this could account for a more vulnerable bone.
doi:10.1016/j.bone.2012.12.038
The intestinal calcium absorption inhibition in diabetes mellitus occurs with alteration in the antioxidant system V.A. Rodríguez, M.E. Peralta López, M.A. Rivoira, N.G. Tolosa de Talamoni Laboratorio de Metabolismo Fosfocálcico “Dr.Cañas”, Cát. de Bioq. y Biol. Mol., Fac. de Cs. Médicas, Universidad Nacional de Córdoba, Argentina Previous studies of our laboratory demonstrated that duodenal oxidative stress is associated with a reduction of intestinal calcium absorption. The aim of this work was to analyze the duodenal antioxidant system in an experimental model of DM. Twomonth old male Wistar rats were divided into two groups: a) controls and b) treated with streptozotocin (single intraperitoneal injection of 60 mg/kg body weight in 100 mM citrate buffer pH 4.5) after a 12-hour fast. Glucose in serum and urine was determined before the induction as well as after 5 days, 1 and 2 months. Rats with glycemia over 250 mg/dl were considered diabetic. Calcium, phosphorus and glycosilated hemoglobin were measured. Total glutathione (GSH), the activity of alkaline phosphatase (AP) and antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)) were determined in duodenal mucosa by spectrophotometry. Controls and diabetic rats had similar levels of calcium and phosphorus in serum. AP activity was significantly lower in diabetic rats than in 5 days and 1 month controls after the induction while it was higher 2 months after streptozotocin injection. Total GSH content decreased in diabetic rats as compared with controls at the studied times. SOD activity did not change whereas CAT activity increased in diabetic rats