Increased Osteoblastic and Osteocytic in Vitro Cell Viability by Yerba Mate (Ilex paraguariensis).

BACKGROUND: Yerba mate (YM, Ilex paraguariensis) consumption beneficially affects the bones. However, whether YM components exert their effect on bone cells directly remains elusive. METHODS: We evaluated how main YM components affect osteoblastic (MC3T3-E1) and osteocytic (MLO-Y4) cells in vitro when administered separately or in an aqueous extract. MC3T3-E1 and MLO-Y4 cells were exposed to three different experimental conditions: (1) Caffeine, chlorogenic acid, and their combinations; (2) Caffeine, rutin, and their combinations; (3) Aqueous YM extract. RESULTS: All polyphenol and caffeine concentrations as well as that of their tested combinations significantly increased MC3T3-E1 cell viability from 16.6% to 34.8% compared to the control. In MLO-Y4 cells, the lowest rutin and the two highest caffeine concentrations significantly increased cell viability by 11.9, 14.9, and 13.7%, respectively. While rutin and caffeine combinations tended to increase MLO-Y4 cell viability, different chlorogenic acid and caffeine combinations did not affect it. Finally, the aqueous YM extract significantly increased MLO-Y4, MC3T3-E1, and differentiated MC3T3-E1 cell viability compared to the control without treatment. CONCLUSIONS: YM components (rutin, chlorogenic acid, and caffeine) positively affected bone cells, mainly pre-osteoblast cells. Moreover, the aqueous YM extract significantly increased MLO-Y4, MC3T3-E1, and differentiated MC3T3-E1 cell viabilities indicating an additional relevant nutritional property of YM infusion. Further studies would be required to elucidate the underlying effector mechanism of YM on the bones and its relationship with previously described in vivo positive effects.

Zoledronic acid effect on bone of growing rats / Efecto del ácido zoledrónico en el hueso de ratas en crecimiento

Zoledronic acid (ZA) is an antiresorptive drug used in children with bone diseases like osteogenesis imperfecta, juvenil osteoporosis, fibrous dysplasia and primary bone tumors. The aim of the present study was to evaluate the effects of ZA dose accumulation on growing bone during different periods of treatment in normal rats. Methods: A 4x2 factorial design was used to study the effect of the dose of ZA (D: 0-2.5-12.5-25 µg Z/kg body weight/s.c. weekly) and the length of treatment (T: 15-30 days) in normal female Sprague Dawley rats. Bone morphometric, histomorphometric, densitometric and biomechanical studies were performed. Results: Femoral length and cross-sectional area were affected by both D and T. A significant interaction between D and T was observed in length with a lower value at higher dose and 30 days of treatment. Growth plate of the tibia showed a decrease in total thickness with D and T. Histomorphometric and connectivity parameters of trabecular bone were significantly increased with D and several parameters were also affected by T. Cortical bone strength was increased only with T. Biomechanical parameters of trabecular bone showed significant interaction with greater effect at higher D and T. Conclusion: Even though a mild negative effect of the highest dose of ZA on linear and appositional growth was observed, the other bone parameters evaluated were improved. A careful risk/benefit analysis would lead us to conclude that the mild deleterious effects of ZA during growth are outweighed by the benefit obtained with treatment. (AU)

El ácido zoledrónico (AZ) es un fármaco antirresortivo utilizado en niños con enfermedades óseas como osteogénesis imperfecta, osteoporosis juvenil, displasia fibrosa y tumores óseos primarios. El objetivo del presente estudio fue evaluar los efectos de las dosis acumuladas de AZ en el hueso en crecimiento de ratas hembras normales durante diferentes períodos de tratamiento. Métodos: se utilizó un diseño factorial de 4x2 para estudiar el efecto de la dosis de AZ (D: 0-2,5-12,5-25 µg Z / kg de peso corporal /sc semanalmente) y el período de tratamiento (T: 15-30 días) en ratas Sprague Dawley. Se realizaron estudios óseos morfométricos, histomorfométricos, densitométricos y biomecánicos. Resultados: la longitud y el área de sección transversal del fémur se vieron afectadas tanto por D como por T. Se observó una interacción significativa entre D y T en la longitud obteniéndose un valor más bajo a la dosis más alta y a 30 días de tratamiento. El cartílago de crecimiento de la tibia mostró una disminución en el espesor total con D y T. Los parámetros histomorfométricos y de conectividad del hueso trabecular aumentaron significativamente con D y varios parámetros también se vieron afectados por T. La fortaleza ósea cortical aumentó solo con T. Los parámetros biomecánicos del hueso trabecular mostraron una interacción significativa con un mayor efecto a mayor D y T. Conclusión: a pesar que se observó un leve efecto negativo de la dosis más alta de AZ sobre el crecimiento lineal y aposicional, el resto de los parámetros óseos evaluados mejoraron. Un análisis cuidadoso del riesgo /beneficio permite concluir que los efectos negativos leves del AZ durante el crecimiento son superados por el beneficio obtenido con el tratamiento. (AU)

Regulation of intestinal calcium absorption by luminal calcium content: role of intestinal alkaline phosphatase.

SCOPE: Intestinal alkaline phosphatase is a brush border enzyme that is stimulated by calcium. Inhibition of intestinal alkaline phosphatase increases intestinal calcium absorption. We hypothesized that intestinal alkaline phosphatase acts as a minute-to-minute regulatory mechanism of calcium entry. The aim of this study was to evaluate the mechanism by which intestinal luminal calcium controls intestinal calcium absorption. METHODS AND RESULTS: We performed kinetic studies with purified intestinal alkaline phosphatase and everted duodenal sacs and showed that intestinal alkaline phosphatase modifies the luminal pH as a function of enzyme concentration and calcium luminal content. A decrease in pH occurred simultaneously with a decrease in calcium absorption. The inhibition of intestinal alkaline phosphatase by l-phenylalanine caused an increase in calcium absorption. This effect was also confirmed in calcium uptake experiments with isolated duodenal cells. CONCLUSION: Changes in luminal pH arising from intestinal alkaline phosphatase activity induced by luminal calcium concentration modulate intestinal calcium absorption.

Chicken eggshell as suitable calcium source at home.

AIM: Taken into consideration that the deficiency of calcium (Ca) in the diet is a common problem, the aim of this work was to study the chicken eggshell as Ca source at home. It was evaluated: (1) different mechanisms to process eggshells and find an easy way to determine the required amount of Ca at home and; (2) the flavor and the texture for eggshell fortified food. METHODS: Chemical and mechanical methods of eggshell processing were evaluated. Changes in flavor and texture were evaluated in volunteers coordinated by a professional chef. RESULTS: A single eggshell contains 2.07 ± 0.18 g of Ca; therefore half an eggshell could provide the amount of Ca needed by adult human beings per day. The best way to use chicken eggshell as Ca dietary supplement is powdered to add to bread, pizza or spaghetti as there were small changes in texture and no changes in flavor.

Reguladores clásicos y noveles del metabolismo del fosfato: [revisión] / Classical and novels regulators of phosphate metabolism: [review]

El fosfato es la forma principal en que se encuentra el elemento fósforo en el organismo. Participa en procesos como el metabolismo energético, la transducción de señales y el control de actividad enzimática. Es esencial para el desarrollo y la mineralización del esqueleto. Su homeostasis es compleja y está regulada principalmente por la acción conjunta de la hormona paratiroidea, la vitamina D y el recientemente identificado FGF23, los cuales actúan de manera coordinada sobre intestino, riñón y hueso. En este trabajo se revisan los conceptos conocidos de la fisiología normal del fosfato y se describe el rol del FGF23 en su homeostasis. Además, se refieren algunos desórdenes asociados a variaciones en los niveles circulantes de este factor.

Effect of the administration of monofluorophosphate on alpha-macroglobulin levels and the clinical course of pancreatitis in rats.

Clinical course of pancreatitis depends partially on the proteinases-antiproteinases balance. Monofluorophosphate (CAS 10163-15-2, MFP) binds to plasmatic antiproteinase alpha-macroglobulin (AM), modifies its homeostasis and, as a consequence, has potential effects on the progression of pancreatitis and other inflammatory processes. The progress of incomplete closed duodenal loop induced pancreatitis was studied in rats with AM homeostasis perturbed by the oral administration of MFP. Twelve rats received 80 micromol MFP/day orally for one month before the induction of pancreatitis. Controls did not receive MFP. Plasmatic amylase activity and AM levels were measured. The day of death was recorded and histopathology of pancreas was performed. Higher survival and less histopathologic changes were observed in rats treated with MFP previous to pancreatitis compared to rats without MFP. Amylase activities were higher in controls and AM levels decreased significantly in controls respect to MFP-treated animals. Higher survival, lower amylasemia and less pancreatic damage in MFP-treated animals suggest a protective effect of the drug in the clinical course of pancreatitis.