RESUMO
Introduction: Diabetes mellitus (DM) impairs fracture healing and is associated with susceptibility to infection, which further inhibits fracture healing. While intermittent parathyroid hormone (1-34) (iPTH) effectively improves fracture healing, it is unknown whether infection-associated impaired fracture healing can be rescued with PTH (teriparatide). Methods: A chronic diet-induced type 2 diabetic mouse model was used to yield mice with decreased glucose tolerance and increased blood glucose levels compared to lean-fed controls. Methicillin-resistant Staphylococcus aureus (MRSA) was inoculated in a surgical tibia fracture model to simulate infected fracture, after which mice were treated with a combination of antibiotics and adjunctive teriparatide treatment. Fracture healing was assessed by Radiographic Union Scale in Tibial Fractures (RUST), micro-computed tomography (µCT), biomechanical testing, and histology. Results: RUST score was significantly poorer in diabetic mice compared to their lean nondiabetic counterparts. There were concomitant reductions in micro-computed tomography (µCT) parameters of callus architecture including bone volume/total volume, trabecular thickness, and total mineral density in type 2 diabetes mellitus (T2DM) mice. Biomechanicaltesting of fractured femora demonstrated diminished torsional rigidity, stiffness, and toughness to max torque. Adjuvant teriparatide treatment with systemic antibiotic therapy improved numerous parameters of bone microarchitecture bone volume, increased connectivity density, and increased trabecular number in both the lean and T2DM group. Despite the observation that poor fracture healing in T2DM mice was further impaired by MRSA infection, adjuvant iPTH treatment significantly improved fracture healing compared to antibiotic treatment alone in infected T2DM fractures. Discussion: Our results suggest that teriparatide may constitute a viable adjuvant therapeutic agent to improve bony union and bone microarchitecture to prevent the development of septic nonunion under diabetic conditions.
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Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Staphylococcus aureus Resistente à Meticilina , Camundongos , Animais , Consolidação da Fratura , Teriparatida/uso terapêutico , Teriparatida/farmacologia , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/tratamento farmacológico , Microtomografia por Raio-X , Hormônio Paratireóideo/farmacologia , Hormônio Paratireóideo/uso terapêuticoRESUMO
Hypoparathyroidism (HypoPT) is a disorder characterized by hypocalcemia, low or absent parathyroid hormone (PTH) levels, reduced bone remodeling, and high areal bone mineral density (aBMD). PTH is a therapeutic option, yet data on the prolonged clinical and skeletal effects of PTH treatment are limited. We tracked annual daily doses of calcium and active vitamin D supplements, calciotropic biochemistries, estimated glomerular filtration rate (eGFR), and aBMD measurements in 27 HypoPT patients (16 postsurgical, 11 nonsurgical) who were treated with recombinant human PTH(1-84) [rhPTH(1-84)] for at least 8 (n = 27) and up to 12 (n = 14) years. We also performed high-resolution-peripheral quantitative computed tomography (HRpQCT) imaging and report results at baseline, 5, 8, and 12 years of rhPTH(1-84) treatment. With prolonged use of rhPTH, reductions in the need for supplemental calcium and active vitamin D were maintained. The eGFR did not decline. Serum calcium was maintained within the lower limit of the normal range. aBMD by dual-energy X-ray absorptiometry (DXA) showed an increase at the lumbar spine and a decrease at the distal 1/3 radius. By HRpQCT, cortical volumetric BMD (vBMD) at the tibia decreased at year 5: -20.0% ± 1.5%. The magnitude of this reduction was mitigated in year 8: -8.5% ± 1.6% and in year 12: -10.3% ± 2.2% but all were significantly below the mean baseline value (p < 0.001). A similar pattern of decline was observed at the radius. Cortical porosity progressively increased at the tibia in year 5: 17.4% ± 10% (p < 0.05), year 8: 55.2% ± 11% (p < 0.001), and year 12: 83.5% ± 14% (p < 0.001). A similar pattern of increase was observed at the radius. Failure load, which was higher than normal at baseline, decreased but remained above normal at year 12. This is the longest experience, to date, with PTH therapy in HypoPT. These results demonstrate sustained biochemical stability but overall decreases in bone mass. © 2023 American Society for Bone and Mineral Research (ASBMR).
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Cálcio , Hipoparatireoidismo , Humanos , Hormônio Paratireóideo/farmacologia , Hormônio Paratireóideo/uso terapêutico , Hipoparatireoidismo/diagnóstico por imagem , Hipoparatireoidismo/tratamento farmacológico , Osso e Ossos , Densidade Óssea , Absorciometria de Fóton , Vitamina D , Cálcio da DietaRESUMO
Introduction: An antibacterial and pro-osteogenic coaxially electrospun nanofiber guided bone regeneration (GBR) membrane was fabricated to satisfy the complicated and phased requirements of GBR process. Methods: In this study, we synthesize dual-functional coaxially electrospun nanofiber GBR membranes by encapsulating parathyroid hormone (PTH) in the core layer and magnesium oxide nanoparticles (MgONPs) in the shell layer (MgONPs-PCL/PTH-PCL). Herein, the physicochemical characterization of MgONPs-PCL/PTH-PCL, the release rates of MgONPs and PTH, and antibacterial efficiency of the new membrane were evaluated. Furthermore, the pro-osteogenicity of the membranes was assessed both in-vitro and in-vivo. Results: We successfully fabricated a coaxially electrospun nanofiber MgONPs-PCL/PTH-PCL membrane with the majority of nanofibers (>65%) ranged from 0.40~0.60µm in diameter. MgONPs-PCL/PTH-PCL showed outstanding antibacterial potential against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) through the release of MgONPs. We also discovered that the incorporation of MgONPs significantly prolonged the release of PTH. Furthermore, both the in-vivo and in-vitro studies demonstrated that high dosage of PTH promoted pro-osteogenicity of the membrane to improve bone regeneration efficacy with the presence of MgONPs. Conclusion: The new composite membrane is a promising approach to enhance bone regeneration in periodontitis or peri-implantitis patients with large-volume bone defects.
Assuntos
Anti-Infecciosos , Nanopartículas , Humanos , Óxido de Magnésio , Materiais Biocompatíveis/química , Hormônio Paratireóideo/farmacologia , Escherichia coli , Staphylococcus aureus , Regeneração Óssea , Anti-Infecciosos/farmacologia , Poliésteres/química , Antibacterianos/farmacologiaRESUMO
In the present study, we examined the systemic and direct effects of parathyroid hormone (PTH) and fibroblast growth factor-23 (FGF-23) on duodenal, jejunal, and ileal Mg2+ absorption. The rats were injected with FGF-23 or PTH for 5 h before collecting the duodenum, jejunum, and ileum for Mg2+ transport analysis in Ussing chambers. The duodenum, jejunum, and ileum were directly exposed to FGF-23, PTH, or FGF-23 plus PTH with or without cell signaling inhibitors for 150 min in Ussing chambers prior to performing the Mg2+ transport study. The small intestinal tissues were also subjected to western blot analyses for FGF receptor (FGFR), PTH receptor (PTHR), Klotho, transient receptor potential melastatin 6 (TRPM6), and cyclin as well as the cystathionine ß-synthase domain divalent metal cation transport mediator 4 (CNNM4) expression. The small intestine abundantly expressed FGFR and PTHR proteins, whereas, Klotho was not expressed in rat small intestine. Systemic PTH or FGF-23 injection significantly suppressed transcellular Mg2+ transport in the duodenum and jejunum. Direct FGF-23-, PTH-, or FGF-23 plus PTH exposure also suppressed transcellular Mg2+ absorption in the duodenum and jejunum. There was no additional inhibitory effect of PTH and FGF-23 on intestinal Mg2+ absorption. The inhibitory effect of PTH, FGF-23, or FGF-23 plus PTH was abolished by Gö 6850. Systemic PTH- or FGF-23-injection significantly decreased membranous TRPM6 expression, but increased cytosolic CNNM4 expression in the duodenum, jejunum, and ileum. In the present study, we propose a novel magnesiotropic action of PTH and FGF-23 by modulating small intestinal Mg2+ absorption.
Assuntos
Proteínas de Transporte de Cátions , Hormônio Paratireóideo , Animais , Proteínas de Transporte de Cátions/metabolismo , Fator de Crescimento de Fibroblastos 23 , Fatores de Crescimento de Fibroblastos/metabolismo , Absorção Intestinal , Intestino Delgado/metabolismo , Magnésio/metabolismo , Hormônio Paratireóideo/metabolismo , Hormônio Paratireóideo/farmacologia , RatosRESUMO
As an important hormone that regulates the balance of calcium and phosphorus, parathyroid hormone (PTH) has also been found to have an important function in intervertebral disc degeneration (IVDD). Our aim was to investigate the mechanism by which PTH alleviates IVDD. In this study, the PTH 1 receptor was found to be highly expressed in severely degenerated human nucleus pulposus (NP) cells. We found in the mouse model of IVDD that supplementation with exogenous PTH alleviated the narrowing of the intervertebral space and the degradation of the extracellular matrix (ECM) caused by tail suspension (TS). In addition, inflammation, oxidative stress, and apoptosis levels were significantly increased in the intervertebral disc tissues of TS-induced mice, and the activity of NP cells was decreased. TS also led to the downregulation of Sonic hedgehog (SHH) signalling pathway-related signal molecules in NP cells such as SHH, Smoothened, and GLI1. However, supplementation with exogenous PTH can reverse these changes. In vitro, PTH also promotes the activity of NP cells and the secretion of ECM. However, the antagonist of the SHH signalling pathway can inhibit the therapeutic effect of PTH on NP cells. In addition, a cAMP-response element-binding protein, as an important transcription factor, was found to mediate the promotion of PTH on the SHH signalling pathway. Our results revealed that PTH can alleviate IVDD by inhibiting inflammation, oxidative stress, and apoptosis and improving the activity of NP cells via activating the SHH signalling pathway.
Assuntos
Proteína de Ligação a CREB/metabolismo , Proteínas Hedgehog/metabolismo , Inflamação/tratamento farmacológico , Degeneração do Disco Intervertebral/tratamento farmacológico , Hormônio Paratireóideo/uso terapêutico , Animais , Apoptose , Modelos Animais de Doenças , Humanos , Masculino , Camundongos , Estresse Oxidativo , Hormônio Paratireóideo/farmacologia , Transdução de SinaisRESUMO
Although the nonselective ß-blocker, propranolol, improves bone density with parathyroid hormone (PTH) treatment in mice, the mechanism of this effect is unclear. To address this, we used a combination of in vitro and in vivo approaches to address how propranolol influences bone remodeling in the context of PTH treatment. In female C57BL/6J mice, intermittent PTH and propranolol administration had complementary effects in the trabecular bone of the distal femur and fifth lumbar vertebra (L5 ), with combination treatment achieving microarchitectural parameters beyond that of PTH alone. Combined treatment improved the serum bone formation marker, procollagen type 1 N propeptide (P1NP), but did not impact other histomorphometric parameters relating to osteoblast function at the L5 . In vitro, propranolol amplified the acute, PTH-induced, intracellular calcium signal in osteoblast-like cells. The most striking finding, however, was suppression of PTH-induced bone resorption. Despite this, PTH-induced receptor activator of nuclear factor κ-B ligand (RANKL) mRNA and protein levels were unaltered by propranolol, which led us to hypothesize that propranolol could act directly on osteoclasts. Using in situ methods, we found Adrb2 expression in osteoclasts in vivo, suggesting ß-blockers may directly impact osteoclasts. Consistent with this, we found propranolol directly suppresses osteoclast differentiation in vitro. Taken together, this work suggests a strong anti-osteoclastic effect of nonselective ß-blockers in vivo, indicating that combining propranolol with PTH could be beneficial to patients with extremely low bone density. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Reabsorção Óssea , Hormônio Paratireóideo , Animais , Reabsorção Óssea/tratamento farmacológico , Reabsorção Óssea/metabolismo , Osso e Ossos , Feminino , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Osteoblastos , Osteoclastos/metabolismo , Osteogênese , Hormônio Paratireóideo/metabolismo , Hormônio Paratireóideo/farmacologia , Propranolol/metabolismo , Propranolol/farmacologiaRESUMO
Vitamin D deficiency, persistent hyperparathyroidism, and bone loss are common after kidney transplantation (KTx). However, limited evidence exists regarding the effects of cholecalciferol supplementation on parathyroid hormone (PTH) and bone loss after KTx. In this prespecified secondary endpoint analysis of a randomized controlled trial, we evaluated changes in PTH, bone metabolic markers, and bone mineral density (BMD). At 1 month post-transplant, we randomized 193 patients to an 11-month intervention with cholecalciferol (4000 IU/d) or placebo. The median baseline 25-hydroxyvitamin D (25[OH]D) level was 10 ng/mL and 44% of participants had osteopenia or osteoporosis. At the end of the study, the median 25(OH)D level was increased to 40 ng/mL in the cholecalciferol group and substantially unchanged in the placebo group. Compared with placebo, cholecalciferol significantly reduced whole PTH concentrations (between-group difference of -15%; 95% confidence interval [CI] -25 to -3), with greater treatment effects in subgroups with lower 25(OH)D, lower serum calcium, or higher estimated glomerular filtration rate (pint < 0.05). The percent change in lumbar spine (LS) BMD from before KTx to 12 months post-transplant was -0.2% (95% CI -1.4 to 0.9) in the cholecalciferol group and -1.9% (95% CI -3.0 to -0.8) in the placebo group, with a significant between-group difference (1.7%; 95% CI 0.1 to 3.3). The beneficial effect of cholecalciferol on LS BMD was prominent in patients with low bone mass pint < 0.05). Changes in serum calcium, phosphate, bone metabolic markers, and BMD at the distal radius were not different between groups. In mediation analyses, change in whole PTH levels explained 39% of treatment effects on BMD change. In conclusion, 4000 IU/d cholecalciferol significantly reduced PTH levels and attenuated LS BMD loss after KTx. This regimen has the potential to eliminate vitamin D deficiency and provides beneficial effects on bone health even under glucocorticoid treatment. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Transplante de Rim , Osteoporose , Deficiência de Vitamina D , Densidade Óssea , Colecalciferol/farmacologia , Colecalciferol/uso terapêutico , Suplementos Nutricionais , Humanos , Transplante de Rim/efeitos adversos , Osteoporose/tratamento farmacológico , Hormônio Paratireóideo/farmacologia , Vitamina D , Deficiência de Vitamina D/tratamento farmacológicoRESUMO
BACKGROUND: In chronic kidney disease, serum phosphorus (P) elevations stimulate parathyroid hormone (PTH) production, causing severe alterations in the bone-vasculature axis. PTH is the main regulator of the receptor activator of nuclear factor κB (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) system, which is essential for bone maintenance and also plays an important role in vascular smooth muscle cell (VSMC) calcification. The discovery of a new RANKL receptor, leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4), which is important for osteoblast differentiation but with an unknown role in vascular calcification (VC), led us to examine the contribution of LGR4 in high P/high PTH-driven VC. METHODS: In vivo studies were conducted in subtotally nephrectomized rats fed a normal or high P diet, with and without parathyroidectomy (PTX). PTX rats were supplemented with PTH(1-34) to achieve physiological serum PTH levels. In vitro studies were performed in rat aortic VSMCs cultured in control medium, calcifying medium (CM) or CM plus 10-7 versus 10-9 M PTH. RESULTS: Rats fed a high P diet had a significantly increased aortic calcium (Ca) content. Similarly, Ca deposition was higher in VSMCs exposed to CM. Both conditions were associated with increased RANKL and LGR4 and decreased OPG aorta expression and were exacerbated by high PTH. Silencing of LGR4 or parathyroid hormone receptor 1 (PTH1R) attenuated the high PTH-driven increases in Ca deposition. Furthermore, PTH1R silencing and pharmacological inhibition of protein kinase A (PKA), but not protein kinase C, prevented the increases in RANKL and LGR4 and decreased OPG. Treatment with PKA agonist corroborated that LGR4 regulation is a PTH/PKA-driven process. CONCLUSIONS: High PTH increases LGR4 and RANKL and decreases OPG expression in the aorta, thereby favouring VC. The hormone's direct pro-calcifying actions involve PTH1R binding and PKA activation.
Assuntos
Miócitos de Músculo Liso/metabolismo , Osteoprotegerina/metabolismo , Hormônio Paratireóideo/farmacologia , Ligante RANK/metabolismo , Receptor Ativador de Fator Nuclear kappa-B/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Calcificação Vascular/metabolismo , Animais , Hormônios e Agentes Reguladores de Cálcio/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Ligantes , Masculino , NF-kappa B/metabolismo , Osteoprotegerina/genética , Ligante RANK/genética , Ratos , Ratos Wistar , Receptor Ativador de Fator Nuclear kappa-B/genética , Receptores Acoplados a Proteínas G/genéticaRESUMO
LA-PTH is a long-acting parathyroid hormone (PTH) peptide analogue in preclinical development for hypoparathyroidism (HP). Like native PTH, LA-PTH contains a methionine at position 8 (Met8) that is predicted to be critical for function. We assessed the impact of Met oxidation on the functional properties of LA-PTH and control PTH ligands. Oxidation of PTH(1-34) resulted in marked (~20-fold) reductions in binding affinity on the PTH receptor-1 (PTHR1) in cell membranes, similarly diminished potency for 3',5'-cyclic AMP signaling in osteoblastic cell lines (SaOS-2 and UMR106), and impaired efficacy for raising blood calcium in mice. Surprisingly, oxidation of LA-PTH resulted in little or no change in these functional responses. The signaling potency of oxidized-LA-PTH was, however, reduced approximately 40-fold compared to LA-PTH in cells expressing a PTHR1 construct that lacks the N-terminal extracellular domain (ECD). Molecular modeling revealed that while Met8 of both LA-PTH and PTH(1-34) is situated within the orthosteric ligand-binding pocket of the receptor's transmembrane domain bundle (TMD), the Met8 sidechain position is shifted for the 2 ligands so that on Met8 oxidation of PTH(1-34), steric clashes occur that are not seen with oxidized LA-PTH. The findings suggest that LA-PTH and PTH(1-34) engage the receptor differently in the Met8-interaction environment of the TMD bundle, and that this interaction environment can be allosterically influenced by the ECD component of the ligand-receptor complex. The findings should be useful for the future development of novel PTH-based peptide therapeutics for diseases of bone and mineral ion metabolism.
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Hipoparatireoidismo/tratamento farmacológico , Hormônio Paratireóideo/análogos & derivados , Receptor Tipo 1 de Hormônio Paratireóideo/agonistas , Animais , Cálcio/sangue , Linhagem Celular Tumoral , Avaliação Pré-Clínica de Medicamentos , Feminino , Células HEK293 , Humanos , Metionina/metabolismo , Camundongos , Modelos Moleculares , Norleucina , Oxirredução , Hormônio Paratireóideo/metabolismo , Hormônio Paratireóideo/farmacologia , Hormônio Paratireóideo/uso terapêutico , Ratos , Receptor Tipo 1 de Hormônio Paratireóideo/metabolismoRESUMO
BACKGROUND: Bone marrow stromal cells (BMSC) have promise in cartilage tissue engineering, but for their potential to be fully realised, the propensity to undergo hypertrophy must be mitigated. The literature contains diverging reports on the effect of parathyroid hormone (PTH) on BMSC differentiation. Cartilage tissue models can be heterogeneous, confounding efforts to improve media formulations. METHODS: Herein, we use a novel microwell platform (the Microwell-mesh) to manufacture hundreds of small-diameter homogeneous micro-pellets and use this high-resolution assay to quantify the influence of constant or intermittent PTH(1-34) medium supplementation on BMSC chondrogenesis and hypertrophy. Micro-pellets were manufactured from 5000 BMSC each and cultured in standard chondrogenic media supplemented with (1) no PTH, (2) intermittent PTH, or (3) constant PTH. RESULTS: Relative to control chondrogenic cultures, BMSC micro-pellets exposed to intermittent PTH had reduced hypertrophic gene expression following 1 week of culture, but this was accompanied by a loss in chondrogenesis by the second week of culture. Constant PTH treatment was detrimental to chondrogenic culture. CONCLUSIONS: This study provides further clarity on the role of PTH on chondrogenic differentiation in vitro and suggests that while PTH may mitigate BMSC hypertrophy, it does so at the expense of chondrogenesis.
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Condrogênese , Células-Tronco Mesenquimais , Células da Medula Óssea , Diferenciação Celular , Células Cultivadas , Condrócitos , Suplementos Nutricionais , Humanos , Hipertrofia , Hormônio Paratireóideo/farmacologiaRESUMO
Glucocorticoid (GC) therapy decreases bone mass and increases the risk of fractures. We investigated interactions between the GC dexamethasone (DEX) and the bone resorptive agents 1,25(OH)2-vitamin D3 (D3) and parathyroid hormone (PTH) on osteoclastogenesis. We observed a synergistic potentiation of osteoclast progenitor cell differentiation and formation of osteoclasts when DEX was added to either D3- or PTH-treated mouse bone marrow cell (BMC) cultures. Cotreatment of DEX with D3 or PTH increased gene encoding calcitonin receptor (Calcr), acid phosphatase 5, tartrate resistant (Acp5), cathepsin K (Ctsk), and TNF superfamily member 11 (Tnfsf11) mRNA, receptor activator of NF-κB ligand protein (RANKL), numbers of osteoclasts on plastic, and pit formation and release of C-terminal fragment of type I collagen from cells cultured on bone slices. Enhanced RANKL protein expression caused by D3 and DEX was absent in BMC from mice in which the GC receptor (GR) was deleted in stromal cells/osteoblasts. Synergistic interactions between DEX and D3 on RANKL and osteoclast formation were present in BMC from mice with attenuated GR dimerization. These data demonstrate that the GR cooperates with D3 and PTH signaling, causing massive osteoclastogenesis, which may explain the rapid bone loss observed with high dosages of GC treatment.-Conaway, H. H., Henning, P., Lie, A., Tuckermann, J., Lerner, U. H. Glucocorticoids employ the monomeric glucocorticoid receptor to potentiate vitamin D3 and parathyroid hormone-induced osteoclastogenesis.
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Colecalciferol/farmacologia , Dexametasona/farmacologia , Osteogênese/efeitos dos fármacos , Hormônio Paratireóideo/farmacologia , Receptores de Glucocorticoides/metabolismo , Animais , Sinergismo Farmacológico , Deleção de Genes , Regulação da Expressão Gênica/efeitos dos fármacos , Camundongos , Ligante RANK/genética , Ligante RANK/metabolismoRESUMO
Exposure to fluoride from environmental sources remains an overlooked, but serious public health risk. In this study, we looked into the role osteocytes play on the mechanism underlying fluoride induced osteopathology. We analyzed bone formation and resorption related genes generated by osteocytes that were exposed to varied doses of fluoride with and without PTH in vitro. Correspondingly, osteogenesis and osteoclastogenesis related genes were also investigated in rats exposed to fluoride for 8 weeks, and the PTH(1-34)was applied at the last 3 weeks to observe its role in regulating bone turnover upon fluoride treatment. The data in vitro indicated that fluoride treatment inhibited Sost expression of mRNA and protein and stimulated RANKL mRNA protein expression as well as the RANKL/OPG ratio in the primary osteocytes. Single PTH treatment played the similar role on expression of these genes and proteins. The PTH combined administration enhanced the action of fluoride treatment on RNAKL/OPG and SOST/Sclerostin. The up-regulation of RANKL and decreasing of Sost induced by fluoride and/or PTH treatment was validated in vivo and suggests that osteocytes are a major source of RANKL and Sost, both of which play essential roles in fluoride affecting osteogenesis and osteoclastogenesis. Expression of Wnt/ß-catenin was up-regulated in both in vitro osteocytes treated with high dose of fluoride and bone tissue of rats in the presence of fluoride and PTH. In vivo, fluoride and single PTH stimulated bone turnover respectively, furthermore, PTH combined with low dose of fluoride treatment reinforced the osteogenesis and osteoclastogenesis genes expression, however, co-treatment of PTH reversed the effect of high dose of fluoride on osteogenesis and osteoclastogenensis related factors. In conclusion, this study demonstrated that osteocytes play a key role in fluoride activated bone turnover, and PTH participates in the process of fluoride modulating SOST/Sclerostin and RANKL expression.
Assuntos
Remodelação Óssea/efeitos dos fármacos , Fluoretos/toxicidade , Osteócitos/efeitos dos fármacos , Hormônio Paratireóideo/farmacologia , Proteínas Adaptadoras de Transdução de Sinal , Animais , Densidade Óssea/efeitos dos fármacos , Remodelação Óssea/genética , Técnicas de Cocultura , Regulação da Expressão Gênica/efeitos dos fármacos , Glicoproteínas/biossíntese , Peptídeos e Proteínas de Sinalização Intercelular , Masculino , Camundongos , Camundongos Endogâmicos ICR , Osteoclastos/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Cultura Primária de Células , Ligante RANK/biossíntese , Via de Sinalização Wnt/efeitos dos fármacosRESUMO
Context: Reduced health-related quality of life (HRQoL) is common in patients with hypoparathyroidism treated conventionally with calcium and active vitamin D supplements. Objective: To examine the effects of recombinant human parathyroid hormone [rhPTH(1-84)] on HRQoL as measured by the 36-Item Short-Form Health Survey (SF-36) during a multinational, randomized, placebo-controlled study. Patients: Adults (N = 122) with chronic hypoparathyroidism. Intervention(s): After an optimization period when calcium and/or active vitamin D supplements were adjusted to reach target serum calcium levels (8.0 to 9.0 mg/dL; 2.0 to 2.2 mmol/L), patients were randomly assigned to receive placebo (n = 39) or rhPTH(1-84) (n = 83) (starting dose, 50 µg/d, could be titrated up to 100 µg/d); supplement doses were adjusted to maintain target serum calcium levels. Main Outcome Measure(s): Change from baseline (postoptimization, at randomization) to week 24 in HRQoL as assessed by the SF-36. Results: Overall, the between-group differences were not statistically significant. However, in the rhPTH(1-84) group, there were significant improvements in the physical component summary score (P = 0.004), and in body pain (P < 0.05), general health (P < 0.05), and vitality (P < 0.001) domains as compared with baseline values. In the placebo group, there were no significant changes for any domains. The magnitude of change between 0 and 24 weeks in SF-36 scores was negatively correlated with baseline scores, such that patients with lower HRQoL at baseline were more likely to experience improvement in response to treatment. Conclusion: Treatment with rhPTH(1-84) may improve HRQoL in adults with hypoparathyroidism.
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Hipoparatireoidismo/tratamento farmacológico , Hormônio Paratireóideo/farmacologia , Hormônio Paratireóideo/uso terapêutico , Qualidade de Vida , Adulto , Idoso , Idoso de 80 Anos ou mais , Cálcio/sangue , Doença Crônica , Método Duplo-Cego , Feminino , Nível de Saúde , Terapia de Reposição Hormonal , Humanos , Hipoparatireoidismo/sangue , Hipoparatireoidismo/epidemiologia , Masculino , Pessoa de Meia-Idade , Hormônio Paratireóideo/sangue , Proteínas Recombinantes/farmacologia , Proteínas Recombinantes/uso terapêutico , Resultado do Tratamento , Vitamina D/sangueRESUMO
Ovariectomized (OVX) rats with type 2 diabetes mellitus (T2DM) with femur fracture received vehicle, insulin, or insulin plus parathyroid hormone (PTH) treatment for 2 and 3 weeks. Radiography, histomorphometry, histology, and immunohistochemistry in callus were evaluated. INTRODUCTION: Reports about effects of PTH plus insulin on callus formation of osteoporotic fracture with T2DM were limited. This study was designed to investigate the effects of the combination of PTH and insulin on fracture healing in OVX rats with T2DM. METHODS: Two-month-old female rats were randomly divided into five groups: normal fracture (F), OVX fracture (OF), T2DM + OVX fracture (DOF), insulin-treated (2-4 u/daylight, 4-6 u/night, DOFI), and treated with insulin and PTH (50 µg/kg/day, 5 days/week, DOFIP). A closed mid-shaft fracture was established in the right femurs of all rats after 6 weeks of OVX. Rats were euthanized at 2 and 3 weeks post-fracture according to the time schedule, respectively. RESULTS: The administration of insulin alone or insulin combined with PTH significantly increased mineralized bone volume fraction (BV/TV) and connectivity density (Conn.D) compared with those of the DOF group at 3 weeks post-fracture and also increased cartilaginous callus area ratio in the DOFI and DOFIP groups at 2 weeks and bony callus area ratio in the DOFIP groups at both the 2 and 3 weeks post-fracture. CONCLUSIONS: OVX rats with T2DM exhibited a marked delay in the fracture healing process; insulin treatment ameliorated these effects, and the healing process was enhanced following treatment with a combination of insulin and PTH.
Assuntos
Diabetes Mellitus Experimental/fisiopatologia , Diabetes Mellitus Tipo 2/fisiopatologia , Fraturas do Fêmur/tratamento farmacológico , Consolidação da Fratura/efeitos dos fármacos , Hormônio Paratireóideo/uso terapêutico , Animais , Glicemia/metabolismo , Calo Ósseo/diagnóstico por imagem , Calo Ósseo/efeitos dos fármacos , Calo Ósseo/patologia , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/tratamento farmacológico , Avaliação Pré-Clínica de Medicamentos/métodos , Quimioterapia Combinada , Feminino , Fraturas do Fêmur/diagnóstico por imagem , Fraturas do Fêmur/fisiopatologia , Hipoglicemiantes/uso terapêutico , Insulina/uso terapêutico , Fraturas por Osteoporose/diagnóstico por imagem , Fraturas por Osteoporose/tratamento farmacológico , Fraturas por Osteoporose/fisiopatologia , Ovariectomia , Hormônio Paratireóideo/farmacologia , Radiografia , Ratos Sprague-Dawley , Microtomografia por Raio-XRESUMO
The bone regeneration and healing effect of formononetin was evaluated in a cortical bone defect model that predominantly heals by intramembranous ossification. For this study, female Balb/c mice were ovariectomised (OVx) and a drill-hole injury was generated in the midfemoral bones of all animals. Treatment with formononetin commenced the day after and continued for 21 d. Parathyroid hormone (PTH1-34) was used as a reference standard. Animals were killed at days 10 and 21. Femur bones were collected at the injury site for histomorphometry studies using microcomputed tomography (µCT) and confocal microscopy. RNA and protein were harvested from the region surrounding the drill-hole injury. For immunohistochemistry, 5 µm sections of decalcified femur bone adjoining the drill-hole site were cut. µCT analysis showed that formononetin promoted bone healing at days 10 and 21 and the healing effect observed was significantly better than in Ovx mice and equal to PTH treatment in many aspects. Formononetin also significantly enhanced bone regeneration as assessed by calcein-labelling studies. In addition, formononetin enhanced the expression of osteogenic markers at the injury site in a manner similar to PTH. Formononetin treatment also led to predominant runt-related transcription factor 2 and osteocalcin localisation at the injury site. These results support the potential of formononetin to be a bone-healing agent and are suggestive of its promising role in the fracture-repair process.
Assuntos
Regeneração Óssea/efeitos dos fármacos , Osso Cortical/efeitos dos fármacos , Fabaceae/química , Fraturas Ósseas/metabolismo , Isoflavonas/farmacologia , Osteogênese/efeitos dos fármacos , Extratos Vegetais/farmacologia , Animais , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Osso Cortical/patologia , Modelos Animais de Doenças , Fêmur/efeitos dos fármacos , Fêmur/patologia , Fraturas Ósseas/tratamento farmacológico , Isoflavonas/uso terapêutico , Camundongos Endogâmicos BALB C , Osteocalcina/metabolismo , Ovariectomia , Hormônio Paratireóideo/farmacologia , Hormônio Paratireóideo/uso terapêutico , Fitoestrógenos/farmacologia , Fitoestrógenos/uso terapêutico , Fitoterapia , Extratos Vegetais/uso terapêutico , Cicatrização/efeitos dos fármacosRESUMO
Parathyroid hormone (PTH), a pleiotropic hormone that maintains mineral homeostasis, is also essential for controlling pH balance and ion transport across renal and intestinal epithelia. Optimization of luminal pH is important for absorption of trace elements, e.g., calcium and phosphorus. We have previously demonstrated that PTH rapidly stimulated electrogenic [Formula: see text] secretion in intestinal epithelial-like Caco-2 monolayers, but the underlying cellular mechanism, contributions of other ions, particularly Cl- and K+, and long-lasting responses are not completely understood. Herein, PTH and forskolin were confirmed to induce anion secretion, which peaked within 1-3 min (early phase), followed by an abrupt decay and plateau that lasted for 60 min (late phase). In both early and late phases, apical membrane capacitance was increased with a decrease in basolateral capacitance after PTH or forskolin exposure. PTH also induced a transient increase in apical conductance with a long-lasting decrease in basolateral conductance. Anion secretion in both phases was reduced under [Formula: see text]-free and/or Cl--free conditions or after exposure to carbonic anhydrase inhibitor (acetazolamide), CFTR inhibitor (CFTRinh-172), Na+/H+ exchanger (NHE)-3 inhibitor (tenapanor), or K+ channel inhibitors (BaCl2, clotrimazole, and TRAM-34; basolateral side), the latter of which suggested that PTH action was dependent on basolateral K+ recycling. Furthermore, early- and late-phase responses to PTH were diminished by inhibitors of PI3K (wortmannin and LY-294002) and PKA (PKI 14-22). In conclusion, PTH requires NHE3 and basolateral K+ channels to induce [Formula: see text] and Cl- secretion, thus explaining how PTH regulated luminal pH balance and pH-dependent absorption of trace minerals.
Assuntos
Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Hormônio Paratireóideo/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Canais de Potássio Cálcio-Ativados/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Acetazolamida/farmacologia , Potenciais de Ação/efeitos dos fármacos , Androstadienos/farmacologia , Compostos de Bário/farmacologia , Bicarbonatos/metabolismo , Células CACO-2 , Cálcio/metabolismo , Inibidores da Anidrase Carbônica/farmacologia , Cloretos/metabolismo , Cloretos/farmacologia , Cromonas/farmacologia , Clotrimazol/farmacologia , Colforsina/farmacologia , Regulador de Condutância Transmembrana em Fibrose Cística/antagonistas & inibidores , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Condutividade Elétrica , Humanos , Concentração de Íons de Hidrogênio , Transporte de Íons/efeitos dos fármacos , Isoquinolinas/farmacologia , Morfolinas/farmacologia , Fosfatidilinositol 3-Quinases/genética , Inibidores de Fosfoinositídeo-3 Quinase , Fósforo/metabolismo , Potássio/metabolismo , Canais de Potássio Cálcio-Ativados/antagonistas & inibidores , Canais de Potássio Cálcio-Ativados/genética , Pirazóis/farmacologia , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , ATPase Trocadora de Sódio-Potássio/genética , Sulfonamidas/farmacologia , WortmaninaRESUMO
Treatment of secondary pediatric osteoporosis-particularly that due to chronic diseases, immobilization, and necessary medical treatments-is currently limited by a poor understanding of the long-term efficacy and safety of skeletal metabolism modifying drugs. This study aimed to characterize longitudinal effects of representative anabolic (parathyroid hormone, PTH) and anti-catabolic (zoledronic acid, ZA) drugs on skeletal morphology, mechanical strength, and growth in juvenile mice. BALB/cJ mice aged 4 weeks were given PTH(1-34) or vehicle (control) daily for 8 weeks, or 4 weekly doses of ZA, and evaluated at time points 0-26 weeks after treatment initiation. There were no enduring differences in body length or mass between treatment groups. ZA increased femur size as early as week 0, including increased distal femur bone volume and diaphyseal cross-sectional area, persisting through week 26. PTH treatment only transiently increased bone size, including distal femur volume at weeks 4-12. ZA decreased diaphyseal cortical tissue mineral density (TMD) at 12-26 weeks versus controls; PTH decreased TMD only at 2 weeks (vs. controls). ZA increased bending strength at 0-12 weeks and flexural strength at week 4 (vs. controls), but decreased flexural strength and modulus at week 26. PTH treatment increased bending strength only at 4 weeks, and did not affect flexural strength. Overall, ZA rapidly and persistently increased femur strength and size, but compromised bone material quality long-term. In healthy juvenile mice, limited-duration PTH treatment did not exert a strong anabolic effect, and had no adverse effects on femur strength, morphology, or growth. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1707-1715, 2017.
Assuntos
Conservadores da Densidade Óssea/farmacologia , Difosfonatos/farmacologia , Fêmur/efeitos dos fármacos , Imidazóis/farmacologia , Osteoporose/tratamento farmacológico , Hormônio Paratireóideo/farmacologia , Animais , Conservadores da Densidade Óssea/uso terapêutico , Difosfonatos/uso terapêutico , Avaliação Pré-Clínica de Medicamentos , Feminino , Crescimento/efeitos dos fármacos , Imidazóis/uso terapêutico , Camundongos Endogâmicos BALB C , Hormônio Paratireóideo/uso terapêutico , Distribuição Aleatória , Ácido ZoledrônicoRESUMO
We investigated the combinatorial effects of whole-body vertical vibration (WBVV) with the primarily osteoanabolic parathyroid hormone (PTH) and the mainly antiresorptive strontium ranelate (SR) in a rat model of osteoporosis. Ovariectomies were performed on 76 three-month-old Sprague-Dawley rats (OVX, n = 76; NON-OVX, n = 12). After 8 weeks, the ovariectomized rats were divided into 6 groups. One group (OVX + PTH) received daily injections of PTH (40 µg/kg body weight/day) for 6 weeks. Another group (OVX + SR) was fed SR-supplemented chow (600 mg/kg body weight/day). Three groups (OVX + VIB, OVX + PTH + VIB, and OVX + SR + VIB) were treated with WBVV twice a day at 70 Hz for 15 min. Two groups (OVX + PTH + VIB, OVX + SR + VIB) were treated additionally with PTH and SR, respectively. The rats were killed at 14 weeks post-ovariectomy. The lumbar vertebrae and femora were removed for biomechanical and morphological assessment. PTH produced statistically significant improvements in biomechanical and structural properties, including bone mineral density (BMD) and trabecular bone quality. In contrast, SR treatment exerted mild effects, with significant effects in cortical thickness only. SR produced no significant improvement in biomechanical properties. WBVV as a single or an adjunctive therapy produced no significant improvements. In conclusion, vibration therapy administered as a single or dual treatment had no significant impact on bones affected by osteoporosis. PTH considerably improved bone quality in osteoporosis cases and is superior to treatment with SR.
Assuntos
Densidade Óssea/efeitos dos fármacos , Osteoporose/tratamento farmacológico , Osteoporose/metabolismo , Hormônio Paratireóideo/farmacologia , Tiofenos/farmacologia , Vibração/efeitos adversos , Animais , Modelos Animais de Doenças , Feminino , Fêmur/metabolismo , Vértebras Lombares/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
A complex feedback mechanism between parathyroid hormone (PTH), 1,25(OH)2D3 (1,25D), and fibroblast growth factor 23 (FGF-23) maintains mineral homeostasis, in part by regulating calcium and phosphate absorption/reabsorption. Previously, we showed that 1,25D regulates mineral homeostasis by repressing dentin matrix protein 1 (DMP1) via the vitamin D receptor pathway. Similar to 1,25D, PTH may modulate DMP1, but the underlying mechanism remains unknown. Immortalized murine cementoblasts (OCCM.30), similar to osteoblasts and known to express DMP1, were treated with PTH (1-34). Real-time quantitative polymerase chain reaction (PCR) and Western blot revealed that PTH decreased DMP1 gene transcription (85%) and protein expression (30%), respectively. PTH mediated the downregulation of DMP1 via the cAMP/protein kinase A (PKA) pathway. Immunohistochemistry confirmed the decreased localization of DMP1 in vivo in cellular cementum and alveolar bone of mice treated with a single dose (50 µg/kg) of PTH (1-34). RNA-seq was employed to further identify patterns of gene expression shared by PTH and 1,25D in regulating DMP1, as well as other factors involved in mineral homeostasis. PTH and 1,25D mutually upregulated 36 genes and mutually downregulated 27 genes by ≥2-fold expression (P ≤ 0.05). Many identified genes were linked with the regulation of bone/tooth homeostasis, cell growth and differentiation, calcium signaling, and DMP1 transcription. Validation of RNA-seq results via PCR array confirmed a similar gene expression pattern in response to PTH and 1,25D treatment. Collectively, these results suggest that PTH and 1,25D share complementary effects in maintaining mineral homeostasis by mutual regulation of genes/proteins associated with calcium and phosphate metabolism while also exerting distinct roles on factors modulating mineral metabolism. Furthermore, PTH may modulate phosphate homeostasis by downregulating DMP1 expression via the cAMP/PKA pathway. Targeting genes/proteins mutually governed by PTH and 1,25D may be a viable approach for designing new therapies for preserving mineralized tissue health.
Assuntos
Cemento Dentário/efeitos dos fármacos , Proteínas da Matriz Extracelular/antagonistas & inibidores , Hormônio Paratireóideo/farmacologia , Vitamina D/farmacologia , Animais , Western Blotting , Linhagem Celular , Proteínas Quinases Dependentes de AMP Cíclico/fisiologia , Cemento Dentário/fisiologia , Regulação para Baixo/efeitos dos fármacos , Proteínas da Matriz Extracelular/fisiologia , Fator de Crescimento de Fibroblastos 23 , Imunofluorescência , Expressão Gênica/efeitos dos fármacos , Camundongos , Hormônio Paratireóideo/fisiologia , Reação em Cadeia da Polimerase em Tempo Real , Vitamina D/fisiologiaRESUMO
Calcium is an essential element in the diet, but there is continuing controversy regarding its optimal intake, and its role in the pathogenesis of osteoporosis. Most studies show little evidence of a relationship between calcium intake and bone density, or the rate of bone loss. Re-analysis of data from the placebo group from the Auckland Calcium Study demonstrates no relationship between dietary calcium intake and rate of bone loss over 5 years in healthy older women with intakes varying from <400 to >1500 mg day(-1) . Thus, supplements are not needed within this range of intakes to compensate for a demonstrable dietary deficiency, but might be acting as weak anti-resorptive agents via effects on parathyroid hormone and calcitonin. Consistent with this, supplements do acutely reduce bone resorption and produce small short-term effects on bone density, without evidence of a cumulative density benefit. As a result, anti-fracture efficacy remains unproven, with no evidence to support hip fracture prevention (other than in a cohort with severe vitamin D deficiency) and total fracture numbers are reduced by 0-10%, depending on which meta-analysis is considered. Five recent large studies have failed to demonstrate fracture prevention in their primary analyses. This must be balanced against an increase in gastrointestinal side effects (including a doubling of hospital admissions for these problems), a 17% increase in renal calculi and a 20-40% increase in risk of myocardial infarction. Each of these adverse events alone neutralizes any possible benefit in fracture prevention. Thus, calcium supplements appear to have a negative risk-benefit effect, and so should not be used routinely in the prevention or treatment of osteoporosis.