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Modeling effects of dexamethasone on disease progression of bone mineral density in collagen-induced arthritic rats.

ABSTRACT: A mechanism-based model was developed to characterize the crosstalk between proinflammatory cytokines, bone remodeling biomarkers, and bone mineral density (BMD) in collagen-induced arthritic (CIA) rats. Male Lewis rats were divided into five groups: healthy control, CIA control, CIA receiving single 0.225 mg kg(-1) subcutaneous (SC) dexamethasone (DEX), CIA receiving single 2.25 mg kg(-1) SC DEX, and CIA receiving chronic 0.225 mg kg(-1) SC DEX. The CIA rats underwent collagen induction at day 0 and DEX was injected at day 21 post-induction. Disease activity was monitored throughout the study and rats were sacrificed at different time points for blood and paw collection. Protein concentrations of interleukin (IL)-1?, IL-6, receptor activator of nuclear factor kappa-B ligand (RANKL), osteoprotegerin (OPG), and tartrate-resistant acid phosphatase 5b (TRACP-5b) in paws were measured by enzyme-linked immunosorbent assays (ELISA). Disease progression and DEX pharmacodynamic profiles of IL-1?, IL-6, RANKL, and OPG were fitted simultaneously and parameters were sequentially applied to fit the TRACP-5b and BMD data. The model was built according to the mechanisms reported in the literature and modeling was performed using ADAPT 5 software with naïve pooling. Time profiles of IL-1? and IL-6 protein concentrations correlated with their mRNAs. The RANKL and OPG profiles matched previous findings in CIA rats. DEX inhibited the expressions of IL-1?, IL-6, and RANKL, but did not alter OPG. TRACP-5b was also inhibited by DEX. Model predictions suggested that anti-IL-1? therapy and anti-RANKL therapy would result in similar efficacy for prevention of bone loss among the cytokine antagonists.

SUBMITTER: Lon HK

PROVIDER: S-EPMC4618640 | biostudies-literature | 2015 Oct

REPOSITORIES: biostudies-literature

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Modeling effects of dexamethasone on disease progression of bone mineral density in collagen-induced arthritic rats.

Lon Hoi-Kei HK DuBois Debra C DC Earp Justin C JC Almon Richard R RR Jusko William J WJ

Pharmacology research & perspectives 20150803 5

A mechanism-based model was developed to characterize the crosstalk between proinflammatory cytokines, bone remodeling biomarkers, and bone mineral density (BMD) in collagen-induced arthritic (CIA) rats. Male Lewis rats were divided into five groups: healthy control, CIA control, CIA receiving single 0.225 mg kg(-1) subcutaneous (SC) dexamethasone (DEX), CIA receiving single 2.25 mg kg(-1) SC DEX, and CIA receiving chronic 0.225 mg kg(-1) SC DEX. The CIA rats underwent collagen induction at day ...[more]

PMID: 26516581

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Project description:BackgroundSevere gonadal steroid deficiency induces bone loss in adult men; however, the specific roles of androgen and estrogen deficiency in hypogonadal bone loss are unclear. Additionally, the threshold levels of testosterone and estradiol that initiate bone loss are uncertain.MethodsOne hundred ninety-eight healthy men, ages 20-50, received goserelin acetate, which suppresses endogenous gonadal steroid production, and were randomized to treatment with 0, 1.25, 2.5, 5, or 10 grams of testosterone gel daily for 16 weeks. An additional cohort of 202 men was randomized to receive these treatments plus anastrozole, which suppresses conversion of androgens to estrogens. Thirty-seven men served as controls and received placebos for goserelin and testosterone. Changes in bone turnover markers, bone mineral density (BMD) by dual-energy x-ray absorptiometry (DXA), and BMD by quantitative computed tomography (QCT) were assessed in all men. Bone microarchitecture was assessed in 100 men.ResultsAs testosterone dosage decreased, the percent change in C-telopeptide increased. These increases were considerably greater when aromatization of testosterone to estradiol was also suppressed, suggesting effects of both testosterone and estradiol deficiency. Decreases in DXA BMD were observed when aromatization was suppressed but were modest in most groups. QCT spine BMD fell substantially in all testosterone-dose groups in which aromatization was also suppressed, and this decline was independent of testosterone dose. Estradiol deficiency disrupted cortical microarchitecture at peripheral sites. Estradiol levels above 10 pg/ml and testosterone levels above 200 ng/dl were generally sufficient to prevent increases in bone resorption and decreases in BMD in men.ConclusionsEstrogens primarily regulate bone homeostasis in adult men, and testosterone and estradiol levels must decline substantially to impact the skeleton.Trial registrationClinicalTrials.gov, NCT00114114.FundingAbbVie Inc., AstraZeneca Pharmaceuticals LP, NIH.

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Modeling effects of dexamethasone on disease progression of bone mineral density in collagen-induced arthritic rats.

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Modeling effects of dexamethasone on disease progression of bone mineral density in collagen-induced arthritic rats.

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