J Korean Soc Endocrinol.  2005 Aug;20(4):334-343. 10.3803/jkes.2005.20.4.334.

Effect of Sequential Therapy with Incadronate after Withdrawal of Recombinant Human Parathyroid Hormone(1-84) on Bone Quantity and Quality in Ovariectomized Rats

• Rhee Y
• Youn JC
• Won YY
• Baek MH
• Lim SK

• KMID: 2100464
• DOI: http://doi.org/10.3803/jkes.2005.20.4.334

Abstract

BACKGROUND: Human parathyroid hormone(hPTH) is a promising anabolic agent. However, since hPTH (1-34) is available only via injection, and has a critical side effect of causing bone tumors during life-long administration in the rat, it would be practical to use PTH for the shortest possible duration to obtain the maximal effect. In addition, acquired bone mass due to hPTH tend to decrease after drug cessation. To determine the effectiveness of the osteoporosis-reversing concept of lose, restore, and maintain(LRM), recombinant human PTH(1-84)[rhPTH(1-84)] and the respective anti-resorptive agents were sequentially studied.
METHODS
Thirty six, 20-week-old, Sprague-Dawley rats were used in this study. Treatment was started on the 25th week after an ovariectomy, which had been performed at 20weeks of age, with 5weeks of rhPTH (1-84) 100(microgram/kg/d), 5days/wk, followed by the respective sequential therapies for 5 weeks as follows: 1) Ovariectomized rats(OVX, n=6), 2) Sham operated rats(SHAM, n=6), 3) OVX rats with PTH maintenance(PTH-M, n=6), 4) OVX rats treated with PTH then withdrawn(PTH-W, n=6), 5) PTH-treated OVX rats then treated with 17beta-estradiol(PTH-E, 10microgram/d, SQ, 5days/wk, n=6), 6) PTH-treated OVX rats then treated with incadronate(PTH-I, 3mg/kg, per os 5 days/wk, n=6). The bone mineral density(BMD) of the right femurs was measured using dual X-ray absorptiometry(DXA). Microcomputed tomography(microCT) was used to measure the structural parameters of the 2nd lumbar vertebrae. A three-point bending test of the femur and compressive tests of vertebrae were also performed.
RESULTS
Bone quantity data showed that the femoral BMD was significantly higher in the PTH-M and PTH-I groups than in the OVX and PTH-W groups(P<0.05). Measurement of the cortical thickness revealed that only the PTH-M group had a significant increase(P=0.001). The ultimate force(Fu) at the midshaft of the femur was stronger in the PTH-M group than in the OVX group(P<0.001). However, no significant difference was found among the treated groups.
CONCLUSION
PTH withdrawal resulted in the loss of the acquired BMD, but sequential therapy with the anti-resorptive, incadronate, prevented further bone loss. The use of incadronate after rhPTH(1-84), as a sequential regimen, was significantly effective on the maintenance in the bone mass, but further clarification in the improvement in the bone quality is needed.

MeSH Terms

Animals
Female
Femur
Humans*
Lumbar Vertebrae
Osteoporosis
Ovariectomy
Rats*
Rats, Sprague-Dawley
Spine
Teriparatide
X-Ray Microtomography
Teriparatide

Figure

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  Fig. 1 Bone mineral density (BMD, g/cm2) of the right femur. *: P < 0.003 vs. OVX, PTH-W & PTH-E, †: P < 0.05 vs. OVX.

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  Fig. 2 Three-dimensional trabecular microstructures of L2 vertebral body from each group.

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  Fig. 3 Cortical thickness of the mid-diaphysis of the femur. *: P = 0.001 vs. OVX

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  Fig. 4 Fmax of right femur. *: P < 0.005 vs. all other groups, †: P = 0.03 vs. SHAM, P = 0.089 vs. PTH-I

Reference

1. Consensus development conference: Prophylaxis and treatment of osteoporosis. Am J Med. 1991. 90:107–110.

2. NIH Consensus Development Panel on Osteoporosis Prevention, Diagnosis, and Therapy, March 7-29, 2000: highlights of the conference. South Med J. 2001. 94:569–573.

3. Dempster DW, Cosman F, Parisien M, Shen V, Lindsay R. Anabolic actions of parathyroid hormone on bone. Endocr Rev. 1993. 14:690–709.

4. Kneissel M, Boyde A, Gasser JA. Bone tissue and its mineralization in aged estrogen-depleted rats after long-term intermittent treatment with parathyroid hormone (PTH) analog SDZ PTS 893 or human PTH(1-34). Bone. 2001. 28:237–250.

5. Sato M, Zeng GQ, Turner CH. Biosynthetic human parathyroid hormone (1-34) effects on bone quality in aged ovariectomized rats. Endocrinology. 1997. 138:4330–4337.

6. Mashiba T, Burr DB, Turner CH, Sato M, Cain RL, Hock JM. Effects of human parathyroid hormone (1-34), LY333334, on bone mass, remodeling, and mechanical properties of cortical bone during the first remodeling cycle in rabbits. Bone. 2001. 28:538–547.

7. Burr DB, Hirano T, Turner CH, Hotchkiss C, Brommage R, Hock JM. Intermittently administered human parathyroid hormone(1-34) treatment increases intracortical bone turnover and porosity without reducing bone strength in the humerus of ovariectomized cynomolgus monkeys. J Bone Miner Res. 2001. 16:157–165.

8. Alexander JM, Bab I, Fish S, Muller R, Uchiyama T, Gronowicz G, Nahounou M, Zhao Q, White DW, Chorev M, Gazit D, Rosenblatt M. Human parathyroid hormone 1-34 reverses bone loss in ovariectomized mice. J Bone Miner Res. 2001. 16:1665–1673.

9. Vahle JL, Sato M, Long GG, Young JK, Francis PC, Engelhardt JA, Westmore MS, Linda Y, Nold JB. Skeletal changes in rats given daily subcutaneous injections of recombinant human parathyroid hormone (1-34) for 2 years and relevance to human safety. Toxicol Pathol. 2002. 30:312–321.

10. Betancourt M, Wirfel KL, Raymond AK, Yasko AW, Lee J, Vassilopoulou-Sellin R. Osteosarcoma of bone in apatient with primary hyperparathyroidism: a case report. J Bone Miner Res. 2003. 18:163–166.

11. Horwitz M, Stewart A, Greenspan SL. Sequential parathyroid hormone/alendronate therapy for osteoporosis-robbing Peter to pay Paul? J Clin Endocrinol Metab. 2000. 85:2127–2128.

12. Gunness-Hey M, Hock JM. Loss of the anabolic effect of parathyroid hormone on bone after discontinuation of hormone in rats. Bone. 1989. 10:447–452.

13. Tanizawa T, Yamamoto N, Takano Y, Mashiba T, Zhang L, Nishida S, Endo N, Takahashi HE, Fujimoto R, Hori M. Effects of human PTH(1-34) and bisphosphonate on the osteopenic rat model. Toxicol Lett. 1998. 102-103:399–403.

14. Rhee Y, Won YY, Baek MH, Lim SK. Maintenance of Increased Bone Mass After Recombinant Human Parathyroid Hormone(1-84) With Sequential Zoledronate Treatment in Ovariectomized Rats. J Bone Miner Res. 2004. 19(6):931–937.

15. Tang LY, Jee WS, Ke HZ, Kimmel DB. Restoring and maintaining bone in osteopenic female rat skeleton: I. Changes in bone mass and structure. J Bone Miner Res. 1992. 7:1093–1104.

16. Wronski TJ, Yen CF, Qi H, Dann LM. Parathyroid hormone is more effective than estrogen or bisphosphonates for restoration of lost bone mass in ovariectomized rats. Endocrinology. 1993. 132:823–831.

17. Iwaniec UT, Samnegard E, Cullen DM, Kimmel DB. Maintenance of cancellous bone in ovariectomized, human parathyroid hormone [hPTH(1-84)]-treated rats by estrogen, risedronate, or reduced hPTH. Bone. 2001. 29:352–360.

18. Green JR. Chemical and biological prerequisites for novel bisphosphonate molecules: results of comparative preclinical studies. Semin Oncol. 2001. 28:4–10.

19. Ruegsegger P, Koller B, Muller R. A microtomographic system for the nondestructive evaluation of bone architecture. Calcif Tissue Int. 1996. 58:24–29.

20. Turner CH. Biomechanics of bone: determinants of skeletal fragility and bone quality. Osteoporos Int. 2002. 13:97–104.

21. Komatsubara S, Mori S, Mashiba T, Ito M, Li J, Kaji Y, Akiyama T, Miyamoto K, Cao Y, Kawanishi J, Norimatsu H. Long-term treatment of incadronate disodium accumulates microdamage but improves the trabecular bone microarchitecture in dog vertebra. J Bone Miner Res. 2003. 18:512–520.

22. Frost HM, Jee WS. On the rat model of human osteopenias and osteoporoses. Bone Miner. 1992. 18:227–236.

23. Divieti P, Inomata N, Chapin K, Singh R, Juppner H, Bringhurst FR. Receptors for the carboxyl-terminal region of PTH(1-84) are highly expressed in osteocytic cells. Endocrinology. 2001. 142:916–925.

24. Wilker CE, Jolette J, Smith SY, Doyle N, Hardisty JF, Metcalfe AJ, Marriott TB, Fox J, Wells DS. S. A no observable carcinogenic effect dose level identified in Fischer 344 rats following daily treatment with PTH(1-84) for 2 years: Role of the C-terminal PTH receptor? J Bone Mineral Res. 2004. 19:suppl 1. S98. abstract.

25. Shen V, Birchman R, Liang XG, Wu DD, Dempster DW, Lindsay R. Accretion of bone mass and strength with parathyroid hormone prior to the onset of estrogen deficiency can provide temporary beneficial effects in skeletally mature rats. J Bone Miner Res. 1998. 13:883–890.

26. Yamamoto N, Takahashi HE, Tanizawa T, Fujimoto R, Hara T, Tanaka S. Maintenance of bone mass by physical exercise after discontinuation of intermittent hPTH(1-34) administration. Bone Miner. 1993. 23:333–342.

27. Sato M, Zeng GQ, Rowley E, Turner CH. LY353381 x HCl: an improved benzothiophene analog with bone efficacy complementary to parathyroid hormone-(1-34). Endocrinology. 1998. 139:4642–4651.