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Strontium ranelate administered at 625 mg/kg/day for 52 weeks prevented OVX-induced biomechanical properties deterioration by influencing the determinants of bone strength: it prevented bone loss and micro-architecture degradation in association with an effect on intrinsic bone quality. These beneficial effects on bone contribute to explain strontium ranelate antifracture efficacy.

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The reverse transcriptase (RT) inhibitor tenofovir (TFV) is highly effective in the simian immunodeficiency virus (SIV) macaque model of human immunodeficiency virus infection. The current report describes extended safety and efficacy data on 32 animals that received prolonged (>1-to 13-year) daily subcutaneous TFV regimens. The likelihood of renal toxicity (proximal renal tubular dysfunction [PRTD]) correlated with plasma drug concentrations, which depended on the dosage regimen and age-related changes in drug clearance. Below a threshold area under the concentration-time curve for TFV in plasma of ϳ10 g ⅐ h/ml, an exposure severalfold higher than that observed in humans treated orally with 300 mg TFV disoproxil fumarate (TDF), prolonged TFV administration was not associated with PRTD based on urinalysis, serum chemistry analyses, bone mineral density, and clinical observations. At low-dose maintenance regimens, plasma TFV concentrations and intracellular TFV diphosphate concentrations were similar to or slightly higher than those observed in TDF-treated humans. No new toxicities were identified. The available evidence does not suggest teratogenic effects of prolonged low-dose TFV treatment; by the age of 10 years, one macaque, on TFV treatment since birth, had produced three offspring that were healthy by all criteria up to the age of 5 years. Despite the presence of viral variants with a lysine-to-arginine substitution at codon 65 (K65R) of RT in all 28 SIV-infected animals, 6 animals suppressed viremia to undetectable levels for as long as 12 years of TFV monotherapy. In conclusion, these findings illustrate the safety and sustained benefits of prolonged TFV-containing regimens throughout development from infancy to adulthood, including pregnancy.Because at present it is not possible to cure human immunodeficiency virus (HIV) infection, prolonged treatment with combinations of anti-HIV drugs is required in order to prevent disease progression. The feasibility of giving HIV-infected persons a normal life span through chronic treatment will be determined by a number of factors, including compliance and cost, but especially the long-term safety and efficacy of the drugs.The nucleotide reverse transcriptase (RT) inhibitor tenofovir {TFV; 9-[2-(phosphonomethoxy)propyl]adenine}, in the form of its orally bioavailable prodrug TFV disoproxil fumarate (TDF), has become one of the most commonly used anti-HIV drugs due to its favorable efficacy and safety profile, based on data collected over more than 7 years for HIV-infected adults (12,24,35,37,47,49).The acyclic nucleoside phosphonates cidofovir, adefovir, and TFV are renally excreted by a combination of glomerular filtration and active tubular secretion (14,15,18,38). The effective uptake of acyclic nucleoside phosphonates by organic anion transporters in proximal tubules leads to accumulation in tubular cells and dose-limiting toxicity in animals (5, 63). Renal toxicity is usually manifested as renal insufficiency and proximal renal tubular dysfunction (PRTD). Dur...

The objective of the present study was to determine if naturally occurring osteoarthritis of the knee joints that is similar to the condition in humans develops in cynomolgus macaques. Knee joints from 58 young adult (mean age, 7.4 years) female cynomolgus macaques were studied with x-ray densitometry, high-detail radiography, and histology. The animals studied were subjects in a triad designed to examine the effects of the administration of sex steroids on atherosclerosis; except for a control group, the monkeys had been either ovariectomized or treated with sex steroids for 2 years. Therefore, the data were analyzed to determine if these treatments, both of which can influence bone density, affected the severity of osteoarthritis. There was a high prevalence of osteoarthritic lesions, morphologically similar to those seen in humans. Bone changes were more common and severe than cartilage changes and morphologically appeared to precede the cartilage changes. Treatment with testosterone resulted in increased body weight, body mass index, and bone mineral content in the femur and tibia but did not affect the severity of osteoarthritis. These data indicate that naturally occurring osteoarthritis developed in the knee joints of cynomolgus macaques; these animals may be a useful model for the study of osteoarthritis in humans.