Sevelamer Restores Bone Volume and Improves Bone Microarchitecture and Strength in Aged Ovariectomized Rats

Abstract

Sevelamer hydrochloride, a noncalcium phosphate binder, has been shown to reduce coronary artery and aortic calcification, and to improve trabecular bone mineral density in hemodialysis patients with chronic kidney disease. Here, we examined whether sevelamer given orally for 12 wk with normal food could restore bone volume (BV) and strength in aged ovariectomized (OVX) rats starting at 4 wk after OVX. Dual-energy x-ray absorptiometry, microcomputerized tomography, and bone histomorphometry analyses showed that OVX animals receiving sevelamer had increased trabecular BV (51%), trabecular number (43%), trabecular thickness (9%), cortical thickness (16%), mineral apposition rate (103%), bone formation rate (25%), and enhanced cortical and trabecular bone mechanical strength as compared with OVX rats. Sevelamer decreased collagen C telopeptide, increased osteocalcin levels, and decreased phosphate and magnesium levels without affecting calcium levels in the blood. Although sevelamer was not absorbed systemically, it stimulated osteoblast differentiation in BM-derived mesenchymal stem cell cultures, as evaluated by alkaline phosphatase positive colony-forming units, and inhibited recombinant human soluble receptor activator of nuclear factor-kappaB ligand-induced osteoclast differentiation, as evaluated by tartrate-resistant acid phosphatase positive cells in bone mineral-hematopoietic stem cell cultures. Surface enhanced laser desorption/ionization time-of-flight mass spectrometry analysis revealed that 69 proteins were differently expressed after OVX, of which 30% (20 of 69) were reversed to sham activity after sevelamer intake. PTH, fibroblast growth factor-23, and cytokine profile in serum were not significantly changed. Together, these results suggest that sevelamer in food increases the BV and improves biomechanical properties of bone in OVX rats.

Npt2b Deletion Attenuates Hyperphosphatemia Associated with CKD

“…33,34 In the ovariectomized rat model of high turnover with normal kidney function, sevelamer treatment was associated with reduced osteoclast number and activity leading to improved bone quality. 35 In other studies, when mice were placed on a low-phosphate diet, decreased osteoclast numbers were observed, whereas a high-phosphate diet was associated with enhanced bone resorption. 36,37 Zhang et al demonstrated that in Dmp1 hypophosphatemic knockout mice, a reduction in the number of osteoclasts was observed.…”

The effects of non-calcium-based phosphate binders versus calcium-based phosphate binders on cardiovascular calcification and bone remodeling among dialysis patients: a meta-analysis of randomized trials

“…Animals' studies had demonstrated that LC and sevelamer have an anabolic effect on bone tissue. 37,38 All meta-analyses are subject to potential bias because of systematic and random errors. 39 Our meta-analysis of randomized controlled trials may have several limitations.…”

Ten-Year Experience with Sevelamer and Calcium Salts as Phosphate Binders

“…The beneficial effects of sevelamer on bone volume and strength were seen in a non-CKD model of osteoporosis that involved aged ovariectomized rats (70). Treatment with sevelamer raised the total-body bone mineral density in the femur, tibia, and lumbar spine and also increased the BFR, cortical thickness, and bone volume, resulting in improved bone biomechanical properties.…”