Intercellular mediators in bone remodeling regulation in the experimental renal pathology / Mediadores intercelulares de la regulación de la remodelación ósea en un modelo experimental de patología renal

Bone metabolism disorders are characterized by an imbalance of bone resorption and formation in the bone remodeling process. Glucocorticoids that are used to treat kidney diseases exacerbate these disorders. P-selectin and galectin-3 are molecules involved in the sclerotic process in kidney, whereas bone resorption is regulated by the interaction between the nuclear factor activator kappa b receptor (RANK), its ligand (RANKL) and the RANKL decoy receptor osteoprotegerin (OPG). The aim of this study was to investigate the cellular and molecular mechanisms of disruption of bone remodeling regulation processes, reflected by intercellular mediators (RANKL, OPG, P-selectin and galectin-3) in chronic kidney disease experimental model treated with glucocorticoids. Rats were divided into four groups of 10 animals each. The first group, the control group, included intact animals. The second group consisted of rats with impaired bone remodeling resulting from chronic kidney disease (experimental group (CKD). The third group was a group of animals with impaired bone remodeling due to exposure to glucocorticoids (experimental group (GCs)). The fourth group consisted of rats with impaired bone remodeling in chronic kidney disease, followed by exposure to glucocorticoids (experimental group (CKD + GCs)). The effects of CKD and glucocorticoid were evaluated biochemically, histologically and by measuring bone density. An enzymelinked immunoassay was used to measure intercellular mediator levels in the serum. The bone density in the experimental groups was reduced compared to the control group. RANKL levels in animals of three experimental groups were higher than in intact animals. Serum levels of OPG were higher in CKD and GCs groups than in intact animals. At the same time, in the animals' blood serum of the CKD + GCs group, the levels of OPG were lower, than those in animals from the control group. The levels of galectin-3 in the serum of the experimental groups GCs and CKD + GCs were lower than in intact animals. The serum levels of galectin-3 in animals of the CKD group were higher than those in animals from the control group. The levels of P-selectin were lower in the serum of the GCs group than in intact animals. At the same time, the levels of P-selectin were higher in the CKD and CKD + GCs groups, than those in animals from the control group. In conclusion, the study of the complex system of bone remodeling regulation, which includes many factors and their interactions, may lead to the development of new methods for treating patients with chronic kidney disease in order to prevent osteoporosis in the future. (AU)

Las enfermedades metabólicas óseas se caracterizan por un desequilibrio en el proceso de remodelación ósea en los que participan mediadores tales como receptor del activador del factor nuclear- kappa- b (RANK), su ligando (RANKL) y la osteoprotegerina (OPG). Los glucocorticoides, recuentemente empleados en el tratamiento de la enfermedad renal crónica, exacerban este desequilibrio. En la enfermedad esclerótica renal, las moléculas de adhesión celular P-selectina and galectina-3 tienen un rol fundamental. El objetivo de esta trabajo fue estudiar las alteraciones en los mediadores de la remodelación ósea (RANKL, OPG, P-selectina and galectina-3) en un modelo de enfermedad renal crónica con tratamiento glucocorticoideo. Ratas Wistar hembras fueron divididos en 4 grupos: control (C); enfermedad renal crónica con afección de la remodelación ósea (ERC); animales con afección de la remodelación ósea expuestos a glucocorticoides (GC); enfermedad renal crónica con afección de la remodelación ósea tratados con glucocorticoides (ERC+GC). Los efectos de la ERC y los GC fueron evaluados bioquímicamente, histológicamente y por medición de la densidad ósea. RANKL, OPG, Pselectina and galectina-3 se cuantificaron en muestras de sangre venosa empleando enzimoinmuno análisis. En los 3 grupos experimentales la densidad ósea se evidenció reducida y los niveles séricos de RANKL elevados respecto al grupo control. Los niveles de OPG en los grupos ERC y GC fueron superiores mientras que en el grupo ERC+GC menores respecto a los animales controles. Galectina 3 plasmática en GC y ERC+GC se encontró reducida y aumentada en los animales ERC, en comparación con los animales controles. La concentración sérica de P-selectina sérica fue mayor en los grupos ERC y ERC+GC, y menor en los animales GC respecto a los niveles plasmáticos de los animales intactos. El avance del conocimiento sobre la regulación de la remodelación ósea a través de la interacción de mediadores sistémicos, en un futuro, puede conducir al desarrollo de nuevas estrategias terapéuticas para la prevención de la osteoporosis en pacientes con enfermedad renal crónica. (AU)

Beneficial effects of Cuscuta chinensis extract on glucocorticoid-induced osteoporosis through modulation of RANKL/OPG signals

Cuscuta chinensis Lam. (Convolvulaceae) is an important herbal medicine widely used to improve sexual function, treat osteoporosis, and prevent aging, and has been reported to exhibit anti-osteoporotic effects in vitro. However, the activity of Cuscuta chinensis Lam. on glucocorticoid-induced osteoporosis still remains unclear. The present study aimed to assess the protective effect and the underlying mechanism of action of Cuscuta chinensis extract (CCE) against glucocorticoid-induced osteoporosis in vivo. Sprague-Dawley rats were randomly divided into four groups as follows: control group, osteoporosis group, and 2 CCE-treated osteoporosis groups (100 mg·kg-1·day-1). Blood samples and femur bones were collected for immunohistochemistry, biochemical, mRNA expression, and western blot analysis. HPLC analysis revealed that chlorogenic acid, quercetin, and hyperin were the major constituents of CCE. The results indicated that CCE increased bone length, bone weight, and bone mineral density and suppressed dexamethasone (DEX)-induced reduction in body weight. In addition, TRAP staining indicated that CCE reduced osteoclasts in DEX-induced osteoporosis rats. Mechanistically, CCE treatment alleviated the increase of bone resorption markers and the decline of osteogenic markers, which might be partially mediated by regulation of RANKL/OPG and RunX2 pathways. These results suggest that CCE showed promising effects in the protection against glucocorticoid-induced osteoporosis through protecting osteoblasts and suppressing osteoclastogenesis.

Effect of risperidone on proliferation and apoptosis of MC3T3-E1 cells

This aim of this study was to assess the molecular mechanism of osteoporosis in schizophrenia patients with risperidone use. Here, we investigated the effects of risperidone on cellular proliferation and apoptosis of a preosteoblast cell line, MC3T3-E1. Cell viability and apoptotic rate of MC3T3-E1 were detected by cell counting kit-8 and flow cytometry at a serial dose of risperidone and at different time points, respectively. Bone transformation relevant gene serum osteocalcin (BGP), collagen 1, tumor necrosis factor-α (TNF-α), osteoprotegerin (OPG), and receptor activator of nuclear factor-κB ligand (RANKL) mRNA levels were determined by real-time PCR (qPCR). Their protein expression patterns were evaluated using western blot. The results revealed that risperidone dramatically inhibited MC3T3-E1 cell proliferation in a dose-dependent manner. It also significantly induced MC3T3-E1 cell apoptosis. TNF-α gene and protein levels were greatly enhanced after risperidone treatment. In contrast, BGP, collagen 1, OPG, and RANKL gene and protein levels were markedly downregulated. Our study indicated that risperidone suppressed MC3T3-E1 cell proliferation and induced apoptosis. It also regulated BGP gene and protein expression.

Cascada de fracturas vertebrales en paciente osteoporótica al año de suspender Denosumab / Cascade of vertebral fractures in osteoporotic patient one year after Denosumab

Una paciente con osteoporosis había sido tratada por 4 años con ibandronato oral, luego por 1 año con ranelato de estroncio, y finalmente por 4 años con denosumab. En vista de la buena respuesta densitométrica este fármaco fue suspendido a fines de 2015. A los 14 meses la enferma tuvo lumbalgia aguda y se detectó hundimiento del platillo superior de L1, a lo que siguieron en rápida sucesión iguales lesiones en L2 y L3, y acuñamiento de D11 y D12. Se descartaron causas de osteoporosis secundaria. El plan terapéutico incluye corsé ortopédico, analgésicos, y teriparatida. En los dos últimos años se han publicado varios casos de este síndrome.

A patient with osteoporosis had been treated for 4 years with oral ibandronate, then for 1 year with strontium ranelate, and finally for 4 years with denosumab. In view of the good densitometric response to the latter, the drug was discontinued in December 2015. Fourteen months later the patient had acute low back pain; crushing of the upper plate of L1 was detected, followed by similar lesions in L2 and L3, and wedging of D11 and D12. Causes of secondary osteoporosis were ruled out. The therapeutic strategy includes a corset, analgesics, and teriparatide. In the last two years several cases of this syndrome have been reported.

The effects of chitosan oligosaccharides on OPG and RANKL expression in a rat osteoarthritis model

Abstract Purpose: To investigate the effect of chitosan oligosaccharides (COS) against osteoarthritis (OA) and preliminarily discuss the osteoprotegerin (OPG), receptor activator of NF-κB ligand (RANKL) and RANK expression in a rat OA model. Methods: Thirty-six 6-week-old Male SD rats were randomly divided into three groups: sham-operated group(CON), OA-induction group(OA), COS intervention group(n=12/group). At 4 weeks after the operation, COS (50 ul) intervention weekily for consecutive 5 weeks. The OA and CON groups received an injection of 50 ul physiological saline. At death, 11 weeks following surgery, cartilage was harvested and total RNA and protein were extracted. Both the morphological changes of the cartilage were observed and harvested the total RNA and protein. Meanwhile, the expression of OPG, RANKL and RANK in cartilage were determined. Results: The expression of OPG and RANKL were both enhanced in the cartilage of the OA model. Compared with the OA group, COS treatment improved the cartilage damage (both extent and grade). Furthermore, the COS group showed highly OPG and lower RANKL. Simultaneously, COS treatment upregulated the ratio of OPG/RANKL and downregulated the RANKL/RANK. Conclusion: Chitosan oligosaccharides may be used as a unique biological agent to prevent and treat osteoarthritis, and this effect is associated with modulation of the expression of osteoprotegerin and receptor activator of NF-κB ligand.

Effect of sumac extract on serum oxidative status, RANKL/OPG system and alveolar bone loss in experimental periodontitis in rats

Objectives Sumac (Rhus coriaria L.) is widely used spice which has several properties such as antioxidant, anti-inflammatory and antimicrobial. The purpose of this animal study was to evaluate the effects of sumac extract on levels of receptor activator of nuclear factor-kappa B ligand (RANKL), osteoprotegerin (OPG) expression, serum oxidative status, and alveolar bone loss in experimental periodontitis. Material and Methods Twenty-four Wistar rats were separated into three groups: non-ligated (NL, n=8), ligature only (LO, n=8), and ligature and treated with sumac extract (S, n=8) (20 mg/kg per day for 11 days). A 4/0 silk suture was placed around the mandibular right first molars subgingivally; after 11 days, the rats were sacrificed, and alveolar bone loss was histometrically measured. The detection of RANKL and OPG were immunohistochemically performed. Levels of serum total antioxidant status (TAS)/total oxidant status (TOS), and oxidative stress index (OSI) were also analyzed. Results Alveolar bone loss was significantly greater in the LO group compared to the S and NL groups (p<0.05). The number of inflammatory cell infiltrate (ICI) and osteoclasts in the LO group was significantly higher than that of the NL and S groups (p<0.05). The number of osteoblasts in the LO and S groups was significantly higher than that of the NL group (p<0.05). There were significantly more RANKL-positive cells in the LO group than in the S and NL groups (p<0.05). OPG-positive cells were higher in S group than in LO and NL groups (p<0.05). TOS and OSI levels were significantly reduced in S group compared to LO group (P<0.05) and TAS levels were similar in S and NL group (p>0.05). Conclusions The present study showed that systemic administration of sumac extract may reduce alveolar bone loss by affecting RANKL/OPG balance, TOS and OSI levels in periodontal disease in rats. .