alendronate, Fosamax
Contrasting effects of alendronate and clodronate on RAW 264 macrophages: the role of a bisphosphonate metabolite.

Makkonen N, Salminen A, Rogers MJ, Frith JC, Urtti A, Azhayeva E, Monkkonen J.

Department of Pharmaceutics, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio, Finland.

Clodronate (dichloromethylidene-bisphosphonate), a halogen-containing bisphosphonate, can inhibit the release of cytokines from RAW 264 macrophages and has anti-inflammatory properties in rheumatoid arthritis, whilst amino-containing bisphosphonates such as alendronate (4-amino-1-hydroxybutylidene-bisphosphonate), have pro-inflammatory properties and can cause an acute phase response. The basis for these pharmacological properties is unclear. Recently, it was demonstrated that clodronate is metabolised by certain cell lines in vitro to an analogue of ATP, whereas amino-bisphosphonates are not. We therefore investigated whether clodronate can also be metabolised by RAW 264 macrophages and whether intracellular accumulation of the metabolite (AppCCl2p) could account for the anti-inflammatory properties of clodronate. The effect of alendronate and AppCCl2p on the release of cytokines (IL-1beta, IL-6, and TNFalpha) from RAW 264 cells was compared, and the effect of the bisphosphonates and AppCCl2p on the DNA binding activities of transcription factors, NF-kappaB and AP-1, was investigated. Pretreatment of RAW 264 macrophages with alendronate augmented the LPS-stimulated release of IL-1beta and increased the binding of NF-kappaB to DNA in an electrophoretic mobility shift assay. Without LPS-induction, alendronate did not affect cytokine release or NF-kappaB binding. Clodronate was metabolised by RAW 264 cells to AppCCl2p. Like clodronate, AppCCl2p inhibited the LPS-induced release of cytokines and NO from RAW 264 macrophages. Both clodronate and its metabolite also inhibited the LPS-stimulated binding of NF-kappaB to DNA. In conclusion, these results suggest that the metabolite of clodronate may be responsible for the anti-inflammatory properties of clodronate, and that the contrasting effects of different bisphosphonates on the release of cytokines could be mediated partly through changes in the DNA binding activity of NF-kappaB.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10210733&dopt=Abstract alendronate Fosamax



alendronate, Fosamax
Alendronate blocks metalloproteinase secretion and bone collagen I release by PC-3 ML cells in SCID mice.

Stearns ME, Wang M.

Allegheny University of the Health Sciences, Department of Pathology, Philadelphia, PA 19102-1192, USA. stearnsm wpo.auhs.edu

We have previously shown that alendronate, a potent bisphosphonate compound, can prevent human PC-3 ML tumor cell metastasis to the bone (Stearns and Stearns, 1996, Oncol Res, 8, 69-75). In this paper, tumor cells were injected into the bone medullary cavity of SCID mice femurs both in vivo and following isolation in vitro. ELISAs showed that the amount of collagen I released in the bone marrow (i.e. in in vitro experiments) and the blood plasma (i.e. in in vivo experiments) was a function of the time of incubation or the number of cells injected in the femurs. ELISAs also showed that the levels of matrix metalloproteinase (MMP-2 and MMP-9) secreted in the bone medullary cavity of the femurs directly correlated with the extent of collagen 1 release. In vitro experiments carried out with 'live' and 'devitalized bone' yielded similar results suggesting that the tumor cells (not the osteoclasts) were primarily responsible for the bone solubilization observed. Alendronate pretreatment of the SCID mice (0.1 mg/kg biweekly for 3 weeks) (or the tumor cells) blocked both MMP production by the tumor cells (and the osteoclasts) and collagen I release, providing direct evidence that alendronate might be utilized to prevent bone destruction by metastatic tumor cells. Zymography indicated that MMP-2 activation might be responsible for bone solubilization. In addition, the data suggest that the plasma levels of collagen I might be a marker of bone metastasis and osteolysis.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10211982&dopt=Abstract alendronate Fosamax



alendronate, Fosamax
Effect of prostaglandin and bisphosphonate on cancellous bone volume and structure in the ovariectomized rat studied by quantitative three-dimensional nuclear magnetic resonance microscopy.

Takahashi M, Wehrli FW, Wehrli SL, Hwang SN, Lundy MW, Hartke J, Borah B.

Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA.

The purpose of this work was to evaluate the potential of nuclear magnetic resonance microscopy (NMRM) in conjunction with a processing technique to monitor the effect of preventive agents in an ovariectomized (OVX) rat. Twenty-five female Sprague-Dawley rats were OVX at 6 months of age (except for the intact control group), allowed to lose bone for 60 days, and then treated for 60 days. During treatment, animals were administered vehicle, prostaglandin E2 (PGE2; 6 mg/kg), or alendronate (3 microg/kg) subcutaneously once a day. Subsequently, tibiae were harvested and the marrow removed. NMRM was carried out at 9.4 T, with the specimens immersed in 1.2 mM diethylenetriaminepentaacetic acid-gadolinium salt (Gd-DTPA) aqueous solution. A three-dimensional (3D) partial flip-angle pulse sequence was used, providing a 1283 array of (46 microm)3 isotropic voxels. Fifty of the 128 axial images in the 3D data set comprising approximately 2.4 mm volume distal to the growth plate were processed from each specimen using a probability-based method for determining bone volume fraction (BVF), tubularity, contiguity, as well as the mean trabecular plate thickness and separation. PGE2 and alendronate altered BVF consistently at all tibial regions. The effect of alendronate was to keep BVF about midway between intact and OVX, whereas PGE2 returned BVF to intact levels. The other parameters showed similar responses to treatment. The strongest discriminator was trabecular BVF, which could obviously differentiate the groups. The study establishes NMRM as a nondestructive histomorphometric method for the quantitative evaluation of drug response in a rat ovariectomy model.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10320516&dopt=Abstract alendronate Fosamax



alendronate, Fosamax
The effects of nitrogen-containing bisphosphonates on human epithelial (Caco-2) cells, an in vitro model for intestinal epithelium.

Twiss IM, Pas O, Ramp-Koopmanschap W, Den Hartigh J, Vermeij P.

Leiden University Medical Center, Department of Clinical Pharmacy, Leiden, The Netherlands.

Nitrogen-containing bisphosphonates (N-PCP) are bisphosphonates with an increased antiresorptive potency. Aminobisphosphonates, N-PCPs with an amino group, can cause nonspecific gastrointestinal complaints. It is not known whether these side effects are specific for these bisphosphonates or for the whole class of N-PCPs. In this study, we investigated the effects of two aminobisphosphonates (pamidronate and alendronate) and a structurally similar N-PCP (olpadronate) and their three respective calcium complexes on the viability and the intracellular calcium concentration ([Ca2+]i) of cultured Caco-2 cells a model for intestinal epithelium. These cells were also examined for apoptosis or necrosis. In the presence of calcium, pamidronate and alendronate were toxic to the cells, with pamidronate being more toxic than alendronate. Olpadronate induced toxicity only at concentrations more than ten times higher than the toxic concentrations of pamidronate. In the absence of calcium definite signs of toxicity were observed only with pamidronate at clinically relevant concentrations. The complexes of pamidronate and alendronate with calcium were considerably less soluble than the olpadronate calcium complex. There were no signs of apoptosis. [Ca2+]i was transiently raised after treatment with the N-PCPs. Doses at which responses were seen were, respectively, 0.02 mM (pamidronate), 0.3 mM (alendronate), and 2 mM (olpadronate). The peak of response was slightly greater after pamidronate treatment than after alendronate or olpadronate, respectively. In conclusion pamidronate, either as an ion or as a calcium complex, is the most toxic of the bisphosphonates tested for Caco-2 cells. Alendronate was less toxic while olpadronate was the least toxic in presence of calcium. The solubility of the bisphosphonate complexes with calcium may account for these differences in toxicity.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10320527&dopt=Abstract alendronate Fosamax



alendronate, Fosamax
Clinic visits and hospital admissions for care of acid-related upper gastrointestinal disorders in women using alendronate for osteoporosis.

Ettinger B, Pressman A, Schein J.

Division of Research, Kaiser Permanente Medical Care Program, CA 94611-5714, USA.

CONTEXT: About 1 in 3 women taking alendronate for osteoporosis report gastrointestinal symptoms, a rate much higher than that found during clinical trials. OBJECTIVE: To establish the frequency of outpatient visits and hospital admissions for acid-related upper gastrointestinal disorder (ARD) among women taking alendronate and to identify potential risk factors. METHODS: A retrospective database analysis identified 812 women with osteoporosis who had filled one or more 10-mg alendronate prescriptions from October 1995 through October 1996. RESULTS: One hundred (12.3%) of the 812 women received healthcare for ARD, a clinical encounter rate of 28.5 per 100 person-years. A reference group of 362,109 women from the same health plan had 17.6 ARD encounters per 100 person-years. Excluding women who had ARDs before receiving alendronate, alendronate users were 1.6 (95% CI = 1.2, 2.7) times more likely to have an ARD encounter than nonusers. Risk of having ARD increased with age [users aged 70 years and older had a relative risk of 1.5 (95% confidence interval (CI) 1.0-2.30) compared with younger women] and with concurrent use of nonsteroidal anti-inflammatory drugs (NSAIDS) (relative risk 1.7, 95% CI 1.1-2.6). CONCLUSIONS: Elderly alendronate users or those concurrently taking NSAIDS should be carefully monitored because of their high risk of having ARD. Cost/benefit analyses of alendronate treatment for osteoporosis should include costs of treating ARD.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10338731&dopt=Abstract alendronate Fosamax



alendronate, Fosamax
Preclinical safety profile of alendronate.

Peter C, Rodan GA.

Merck Research Laboratories, West Point, Pennsylvania, USA.

Acute toxicity studies showed that the LD50 values of oral alendronate in female animals corresponded to human oral doses of 27,800 mg in rats and 48,300 mg in mice; LD50 values in male animals were even higher. Chronic toxicity studies showed clinically nonrelevant retention of primary spongiosa of bone in areas of endochondral bone formation, serum biochemical changes (reductions in serum concentrations of calcium, phosphate and alkaline phosphatase) and nephrotoxicity. Of the 5 genotoxicity studies performed, 4 showed no evidence of mutagenicity, including those most relevant to human carcinogenic potential. Carcinogenicity studies in rats and mice at maximum tolerated doses showed no increased tumour incidence associated with alendronate treatment. Alendronate had no effect on fertility or reproductive performance in male or female rats receiving oral doses up to 5 mg/kg/day. No adverse developmental effects were noted at doses up to 25 mg/kg/day in rats and 35 mg/kg/day in rabbits. Alendronate had no deleterious effect on bone strength or morphology. The evidence presented in these studies supports the conclusion that alendronate administered to humans at therapeutic doses is a safe drug for the treatment of postmenopausal osteoporosis.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12669734&dopt=Abstract alendronate Fosamax