Bisphosphonates have been shown to attenuate ectopic calcification in experimental uremia. While they are known to reduce bone turnover, the effects on endochondral bone formation have not yet been addressed. To address this issue, we administered male Sprague-Dawley rats weekly subcutaneous injections of either vehicle or ibandronate (1.25 μg/kg body weight) for a total of 10 weeks. The rats were randomly allocated into one of four groups: (1) vehicle-treated, sham-operated rats; (2) ibandronate-treated, sham-operated rats; (3) vehicle-treated, 5/6 nephrectomized rats; (4) ibandronate-treated, 5/6 nephrectomized rats. Bones were double labeled with tetracycline and demeclocycline in vivo, and tibiae were removed for analysis. Weight gain was similar in all groups. Ibandronate reduced body length gain and tibial growth rate in the sham-operated animals but not in the rats showing chronic renal failure (CRF). The height of the proliferative zone of the epiphyseal growth plate was reduced in the ibandronate-treated controls and tended to be reduced in CRF rats. A significant correlation between tibial growth rate and height of the proliferative zone was observed. Mineral apposition rates were significantly reduced in ibandronate-treated, sham-operated rats and tended to be reduced in CRF rats. In conclusion, ibandronate interferes with tibial growth and bone mineralization in young rats with normal and reduced renal function.
Background/Aims: Renal osteodystrophy and eventually osteoporosis are serious long-term complications in children with end-stage renal disease before and after renal transplantation. Strontium (Sr) salts are used for treatment of osteoporosis in adults. Methods: To evaluate the time-dependent effects of Sr on growth plate morphology and their reversibility, chronic renal failure (CRF) rats received either normal or Sr-loaded drinking water (2 g/l; ±200 mg/kg/day) for periods of 2, 6 and 12 weeks with or without subsequent washout periods of 0, 2, 4 or 8 weeks. Results: While weight gain was not affected by Sr loading, a significant enlargement of the entire growth plate, mainly due to expansion of the hypertrophic zone, was already present after 2 weeks. Sr-loaded animals showed increased osteoid areas and reduced bone formation rates at 2, 6 and 12 weeks compared to controls. This was accompanied by reduced PTH levels and increased serum bone alkaline phosphatase activity. After the washout periods these effects were reversed. In general, the height of the hypertrophic zone was positively correlated with osteoid area and negatively correlated with bone formation rate. Conclusion: Moderate Sr loading in CRF rats results in rapid development of rickets, which is reversible after washout.
Three resistant starches (RSs), namely fibre of potatoes (FP), wrinkle pea starch (WPS), and high amylose maize starch (HAMS) with different dietary fibre contents, were supplemented in adults to evaluate their effects on urinary nitrogen and ammonia excretion as well as on faecal nitrogen excretion by means of lactose-[(15)N2]ureide ((15)N-LU) degradation. Twenty subjects received a regular diet either without or with the supplementation of FP, WPS, and HAMS in a randomized order. After administration of (15)N-LU, urine and faeces were collected over 48 and 72 h, respectively, whereas blood was collected after 6 h. The (15)N-abundances were measured by isotope ratio mass spectrometry. In comparison to the dry run, supplementation with RS significantly lowered renal (15)N-excretion (dry run: 43.2%, FP: 34.6%, WPS: 37.9%, HAMS: 36.4%) as well as the corresponding (15)NH3-excretion (dry run: 0.08%, FP: 0.06%, HAMS: 0.05%), clearly indicating a reduced colonic nitrogen generation at high dietary fibre intake.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.