151
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Abstract
Teriparatide, recombinant human parathyroid hormone (1-34) (rhPTH [1-34]), is approved for the treatment of osteoporosis in men and postmenopausal women at high risk for fracture. The best candidates are those who have already had vertebral compression fractures (symptomatic or asymptomatic) or other osteoporosis-related fractures, or those who have very low bone mineral density, in the T score range of -3.5 or below. Teriparatide is the first anabolic drug approved by the US Food and Drug Administration for osteoporosis. It not only dramatically improves bone mass, but also restores bone microarchitecture and increases bone diameter. All of these mechanisms contribute to increasing bone strength and reducing the risk for osteoporosis-related fractures. Although PTH has been used in combination with other agents such as estrogens, calcitonin, and bisphosphonates, the relative benefit of the combined approach versus teriparatide alone for fracture risk reduction has not been shown. In fact, some data suggest that initiating PTH and alendronate together in previously untreated patients or pretreating patients for a short time with alendronate before initiating PTH may somewhat reduce the anabolic response to PTH. There are many unanswered questions regarding PTH, such as the optimal duration of treatment, the optimal sequence of medications for severe osteoporosis, the mechanism of resistance to effect after 18 to 24 months, the effect of subsequent rechallenge with PTH and, most importantly, surrogates to measure PTH effect.
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Affiliation(s)
- Felicia Cosman
- Regional Bone Center, Helen Hayes Hospital, Route 9W, West Haverstraw, New York, NY 10993, USA.
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152
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Miller PD, Bilezikian JP, Deal C, Harris ST, Ci RP. Clinical Use of Teriparatide in the Real World: Initial Insights. Endocr Pract 2004; 10:139-48. [PMID: 15256332 DOI: 10.4158/ep.10.2.139] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To summarize expert opinion regarding clinical application of the recently introduced anabolic agent teriparatide [human parathyroid hormone (1-34)] in treatment of postmenopausal osteoporosis in women, and osteoporosis in men. SUMMARY The anabolic agent teriparatide was approved for clinical use by the Food and Drug Administration (FDA) on November 26, 2002. Since the launch of teriparatide, many more questions about clinical use of this exciting agent have emerged than there are answers provided by clinical trials or FDA-approved product labeling. A group of physicians with a broad range of experience in research and clinical applications of teriparatide met recently to address practical issues related to its use. This manuscript is a compendium of the consensus opinions of the authors that attempts to provide practical answers to many real-world questions being asked about teriparatide therapy since its approval by the FDA.
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Affiliation(s)
- Paul D Miller
- Colorado Center for Bone Research, Lakewood, 80227, USA
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153
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Abstract
OBJECTIVE To review the pharmacology, toxicology, pharmacokinetics, pharmacodynamics, efficacy, safety, therapeutic controversies, administration, patient counseling, and formulary recommendations for teriparatide (rDNA origin). DATA SOURCES A MEDLINE search (1966–May 2003) of articles using the key words parathyroid hormone and osteoporosis, parathyroid hormone and fracture, and teriparatide was conducted to identify relevant literature in the English language. Additional references were obtained from bibliographies of those articles. Some clinical trial data not yet published were obtained from the manufacturer. STUDY SELECTION AND DATA EXTRACTION All articles obtained from the data sources were reviewed; all data deemed relevant were included. DATA SYNTHESIS Teriparatide, recombinant human parathyroid hormone (1–34) [rhPTH (1–34)], is the first anabolic agent to treat postmenopausal women with osteoporosis and men with idiopathic or hypogonadal osteoporosis who are at high risk for osteoporotic fracture. Daily subcutaneous injections of teriparatide significantly increase both spine and hip bone-mineral density (BMD) while decreasing the incidence of fractures in both women and men. Common adverse effects noted with teriparatide use were nausea, headache, dizziness, and arthralgias. An increased incidence of osteosarcoma in rats during preclinical trials with teriparatide led to a black box warning for the drug. CONCLUSIONS Teriparatide substantially increases spine and hip BMD and may offer additional benefits to patients with severe osteoporosis. Clinical trials comparing teriparatide with other available agents to treat osteoporosis are needed to more clearly define its place in therapy. Long-term safety and efficacy are not known.
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Affiliation(s)
- Kimberly A Cappuzzo
- Department of Pharmacy and the Geriatric Pharmacotherapy Program, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23298-0533, USA.
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154
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Abstract
Parathyroid hormone (PTH), given intermittently, is an anabolic agent. PTH has been demonstrated to increase bone mass and reduce vertebral and nonvertebral fractures, and has been approved for use in the US and Europe. PTH is a genetically engineered 34 amino acid protein with the designation teriparatide (recombinant DNA origin) or recombinant human PTH 1-34. A recombinant DNA preparation with all 84 amino acids of the native PTH molecule is in clinical trials. These PTH preparations are self-administered daily injections, and it is approved for women and men at high risk for fractures, including patients with prevalent fractures, low bone mass, and multiple risk factors. PTH is likely to be used most frequently in patients who fracture on therapy, but can be used in high-risk treatment-naïve patients. Previous treatment with alendronate appears to impair the anabolic response of PTH preparations. Patients who have Paget's disease, prior radiation therapy to the skeleton, as well as children and young adults with open epiphyses, are at higher risk for osteosarcoma and should not be given PTH. Patients with hypercalcemia and hyperparathyroidism also should not receive the drug.
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Affiliation(s)
- Chad Deal
- Center for Osteoporosis and Metabolic Bone Disease, Department of Rheumatology, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
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155
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Daragon A, Pouplin S. Potential benefits of intermittent bisphosphonate therapy in osteoporosis. Joint Bone Spine 2004; 71:2-3. [PMID: 14769511 DOI: 10.1016/s1297-319x(03)00156-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2003] [Accepted: 05/16/2003] [Indexed: 11/19/2022]
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156
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Abstract
UNLABELLED The diagnosis and management of osteoporosis have become increasingly more complex as new drugs enter the marketplace and meta-analyses of randomized trials with "other" agents become more prolific. We describe five common clinical scenarios encountered in the practice of osteoporosis medicine and various road maps that could lead to successful therapy. INTRODUCTION The diagnosis and treatment of osteoporosis have changed dramatically in the last decade. Advances in diagnostic technologies and a range of newer treatment options have provided the clinician with a wide array of choices for treating this chronic disease. Despite the issuance of several "guidelines" and practice recommendations, there still remains confusion among clinicians about basic approaches to the management of osteoporosis. This paper should be used as a case-based approach to define optimal therapeutic choices. MATERIALS AND METHODS Five representative cases were selected from two very large clinical practices (Bangor, ME; Pittsburgh, PA). Diagnostic modalities and treatment options used in these cases were selected on an evidence-based analysis of respective clinical trials. Subsequent to narrative choices by two metabolic bone disease specialists (SG and CR), calculation of future fracture risk and selection of potential alternative therapeutic regimens were reviewed and critiqued by an epidemiologist (DB). RESULTS A narrative about each case and possible management choices for each of the five cases are presented with references to justify selection of the various therapeutic options. Alternatives are considered and discussed based on literature and references through July 2003. The disposition of the individual patient is noted at the end of each case. CONCLUSIONS A case-based approach to the management of osteoporosis provides a useful interface between guidelines, evidence-based meta-analyses, and clinical practice dilemmas.
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Affiliation(s)
- Clifford J Rosen
- Maine Center for Osteoporosis Research and Education, St. Joseph Hospital, Bangor, Maine 04401, USA.
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157
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Abstract
The prevalence of osteoporosis in all US postmenopausal women is 17%, and it is as high as 30% in women older than 65. All postmenopausal women should be encouraged to have adequate daily calcium and vitamin D intake, to exercise regularly, and to avoid tobacco and excessive alcohol use. Although the clinical impact and cost-effectiveness of osteoporosis screening tools remain to be established, a rational approach based on current evidence involves using National Osteoporosis Foundation guidelines, Simple Calculated Osteoporosis Risk Estimation, or Osteoporosis Risk Assessment Instrument clinical decision rules to decide when a postmenopausal woman should undergo further evaluation.
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Affiliation(s)
- Gina S Wei
- Department of Medicine, Uniformed Services University of Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
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158
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Abstract
Osteoporosis is a disease that may have a tremendous impact on the lives of many postmenopausal women. It is encouraging that effective treatments for this disease abound and the challenge is to ensure that those most in need of diagnosis or therapy obtain adequate care. Further research is expected to clarify the role of combination therapy or sequential use of different agents for the maximum benefit in fracture protection. There is an array of efficacious options to consider when diagnosing and treating osteoporosis so that patients and their caregivers can remain optimistic about the management of this chronic disease and prevention of future fractures.
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Affiliation(s)
- Sue A Brown
- Division of Endocrinology, Department of Medicine, University of North Carolina-Chapel Hill, Campus Box 7172, Bioinformatics Building 1163A, 130 Mason Farm Road, Chapel Hill, NC 27599-7172, USA
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159
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160
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Abstract
The growing number of patients with osteoporosis in our aging population need "anabolic" drugs to stimulate bone growth, improve bone microarchitecture, and accelerate fracture healing. Potent anabolic agents such as parathyroid hormone (PTH) and some of its adenylyl cyclase-stimulating fragments are either on their way, or have just now reached the clinic. This article discusses how PTHs might stimulate bone growth. The controversial bone anabolic activities of the widely used cholesterol-lowering lipophilic statins and how they might stimulate bone growth are also probed. Also, evidence is presented for leptin, a controller of body fat stores and the ovarian cycle. It has the remarkable property of being an anabolic and antianabolic that uses a hypothalamic factor to restrain osteoblast activity but by itself stimulates osteoblasts and inhibits osteoclasts.
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Affiliation(s)
- James F Whitfield
- Institute for Biological Sciences, National Research Council of Canada, Montreal Road Campus, Building M-54, Ottawa, Ontario K1A 0R6, Canada.
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161
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Abstract
PTH represents an important new advance in the therapy of osteoporosis. As an anabolic agent, its potential might be substantially greater than that of antiresorptive agents. Clear evidence in human trials now documents the ability of PTH to stimulate cancellous bone formation and to reduce fractures. Because antiresorptive agents and PTH work by distinct mechanisms of action, it is possible that the combination of these agents could be significantly more potent than either agent alone. There are other unanswered questions about PTH. More studies are needed to document an anabolic effect on cortical bone. In addition, more large-scale studies are needed to further determine the reduction in nonvertebral fractures with PTH, especially at the hip. More information is also required to determine the possible need for antiresorptive therapy after PTH. Protocols to consider PTH as an intermittent recycling therapy would be of interest. In the future, PTH is likely to be modified for easier and more targeted delivery. Oral or transdermal delivery systems may become available. Recently, Gowen et al [78] have described an oral calcilytic molecule that antagonizes the parathyroid cell calcium receptor, thus stimulating the endogenous release of PTH. This approach could represent a novel endogenous delivery system for intermittent PTH administration. Ultimately, when the anabolic and catabolic mechanisms of PTH can be clearly distinguished, both mechanistically and in molecular terms, it may be possible to develop PTH analogs that are more purely anabolic.
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Affiliation(s)
- Mishaela R Rubin
- Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032, USA
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162
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Hamdy RC. May is osteoporosis month. South Med J 2003; 96:419-20. [PMID: 12911176 DOI: 10.1097/01.smj.0000067662.21765.27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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163
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Cada DJ, Levien T, Baker DE. Teriparatide. Hosp Pharm 2003. [DOI: 10.1177/001857870303800507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Each month, subscribers to The Formulary Monograph Service receive five to six well-documented monographs on drugs that are newly released or are in late Phase III trials. The monographs are targeted to your Pharmacy and Therapeutics Committee. Subscribers also receive monthly one-page summary monographs on the agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation (DUE) is also provided each month. The monographs are published in printed form and on diskettes that allow customization. Subscribers to the The Formulary Monograph Service also receive access to a pharmacy bulletin board, The Formulary Information Exchange (The F.I.X.). All topics pertinent to clinical and hospital pharmacy are discussed on The F.I.X. Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. If you would like information about The Formulary Monograph Service or The F.I.X., call The Formulary at 800–322–4349. The May 2003 monograph topics are enfuvirtide, oxybutynin transdermal, gemifloxacin, efalizumab, and hyaluronidase ovine. The DUE is on enfurvirtide.
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Affiliation(s)
- Dennis J. Cada
- The Formulary, 310 North Riverpoint Boulevard, PO Box 1495, Spokane, WA 99210–1495
| | - Terri Levien
- Drug Information Pharmacist, Drug Information Center, Washington State University Spokane, 310 North Riverpoint Boulevard, PO Box 1495, Spokane, WA 99210–1495
| | - Danial E. Baker
- Drug Information Center and College of Pharmacy, Washington State University Spokane, 310 North Riverpoint Boulevard, PO Box 1495, Spokane, WA 99210–1495
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164
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Abstract
Post-menopausal osteoporosis is characterized by increased fracture risk due to deficiencies in both the quantity and quality of bone. Assessing fracture risk involves combining clinical risk factors, including fall risks, with bone density testing. Treatment strategies are aimed at reducing fracture risk. General nutritional and lifestyle measures are appropriate for all women. Drug treatment is most clearly indicated in post-menopausal women at high current fracture risk. Treatment should also be considered for women at intermediate fracture risk, including those who have both low bone density and other risk factors for fracture. Whether there is practical clinical value in treating low-risk patients is much less clear. Non-pharmacological approaches addressing the consequences of fractures are integral parts of a comprehensive treatment programme. Reducing both the frequency and the effects of falls complements the efforts of treating osteoporosis to reduce the incidence of fractures and their important clinical consequences.
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Affiliation(s)
- Michael R McClung
- Oregon Osteoporosis Center, 5050 NE Hoyt Street, Suite 651, Portland, OR 97210, USA.
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165
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Landin-Wilhelmsen K, Nilsson A, Bosaeus I, Bengtsson BA. Growth hormone increases bone mineral content in postmenopausal osteoporosis: a randomized placebo-controlled trial. J Bone Miner Res 2003; 18:393-405. [PMID: 12619921 DOI: 10.1359/jbmr.2003.18.3.393] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Eighty osteoporotic, postmenopausal women, 50-70 years of age, with ongoing estrogen therapy (HRT), were randomized to recombinant human growth hormone (GH), 1.0 U or 2.5 U/day, subcutaneous, versus placebo. This study was double-blinded and lasted for 18 months. The placebo group then stopped the injections, but both GH groups continued for a total of 3 years with GH and followed for 5 years. Calcium (750 mg) and vitamin D (400 U) were given to all patients. Bone mineral density and bone mineral content were measured with DXA. At 18 months, when the double-blind phase was terminated, total body bone mineral content was highest in the GH 2.5 U group (p = 0.04 vs. placebo). At 3 years, when GH was discontinued, total body and femoral neck bone mineral content had increased in both GH-treated groups (NS between groups). At 4-year follow-up, total body and lumbar spine bone mineral content increased 5% and 14%, respectively, for GH 2.5 U (p = 0.01 and p = 0.0006 vs. placebo). Femoral neck bone mineral density increased 5% and bone mineral content 13% for GH 2.5 U (p = 0.01 vs. GH 1.0 U). At 5-year follow-up, no differences in bone mineral density or bone mineral content were seen between groups. Bone markers showed increased turnover. Three fractures occurred in the GH 1.0 U group. No subjects dropped out. Side effects were rare. In conclusion, bone mineral content increased to 14% with GH treatment on top of HRT and calcium/vitamin D in postmenopausal women with osteoporosis. There seems to be a delayed, extended, and dose-dependent effect of GH on bone. Thus, GH could be used as an anabolic agent in osteoporosis.
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166
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Abstract
Anabolic agents represent an important new advance in the therapy of osteoporosis. Their potential might be substantially greater than the anti-resorptives. Because the anti-resorptives and anabolic agents work by completely distinct mechanisms of action, it is possible that the combination of agents could be significantly more potent than either agent alone. Recent evidence suggests that a plateau in BMD might occur after prolonged exposure to PTH. Anti-resorptive therapy during or after anabolic therapy might prevent this skeletal adaptation. Protocols to consider anabolic agents as intermittent recycling therapy would be of interest. Of all the anabolics, PTH is the most promising. However, there are unanswered questions about PTH. More studies are needed to document an anabolic effect on cortical bone. More large-scale studies are needed to further determine the reduction in nonvertebral fractures with PTH, especially at the hip. In the future, PTH is likely to be modified for easier and more targeted delivery. Oral or transdermal delivery systems may become available. Recently, Gowen et al have described an oral calcilytic molecule that antagonizes the parathyroid cell calcium receptor, thus stimulating the endogenous release of PTH. This approach could represent a novel endogenous delivery system for intermittent PTH administration. Rising expectations that anabolic therapies for osteoporosis will soon play a major role in treating this disease are likely to fuel further studies and the development of even more novel approaches to therapy.
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Affiliation(s)
- Mishaela R Rubin
- Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032, USA
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167
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Horwitz MJ, Tedesco MB, Gundberg C, Garcia-Ocana A, Stewart AF. Short-term, high-dose parathyroid hormone-related protein as a skeletal anabolic agent for the treatment of postmenopausal osteoporosis. J Clin Endocrinol Metab 2003; 88:569-75. [PMID: 12574182 DOI: 10.1210/jc.2002-021122] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PTH-related protein (PTHrP) is homologous with PTH. PTH, an effective anabolic agent for treating osteoporosis, has been shown to stimulate both bone resorption by osteoclasts and bone formation by osteoblasts. We examined whether PTHrP might share anabolic properties in osteoporosis. A 3-month double-blind, prospective, placebo-controlled, randomized clinical trial was performed in 16 healthy postmenopausal women with osteoporosis. All received calcium and vitamin D, and all continued their prior hormone replacement therapy. One group also received daily sc PTHrP (6.56 microg/kg x d, or approximately 400 microg/d), and the other group received placebo injections. The PTHrP group displayed a 4.7% increase in lumbar spine bone mineral density (BMD) and also demonstrated an increase in osteoblastic bone formation, as assessed using serum osteocalcin measurements. In contrast, there was no increase in bone-specific alkaline phosphatase and collagen-1 propeptide or either of two markers of osteoclastic bone resorption, N-telopeptide, or deoxypyridinoline. One subject in the placebo group withdrew from the study, but there were no significant adverse events in the PTHrP group. PTHrP administered sc in high doses for only 3 months appears to be a potent anabolic agent, producing a 4.7% increase in lumbar spine BMD. This compares very favorably to available antiresorptive drugs for osteoporosis and is similar to the increases in BMD at this early time point reported for PTH. Despite the high doses, PTHrP was well tolerated. Larger clinical trials are required to confirm these results and fully assess the anabolic potential of PTHrP in osteoporosis.
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Affiliation(s)
- Mara J Horwitz
- Division of Endocrinology, The University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA
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168
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Abstract
There is a need for "anabolic" drugs that can directly stimulate bone growth, improve bone microarchitecture, accelerate fracture healing, and, thus, restore bone strength to osteoporosis patients and, hopefully, regenerate eroded bone in arthritis patients. The anabolic agents currently leading the way to the clinic are the parathyroid hormone (PTH) and some of its adenylyl cyclase-stimulating fragments. This article is a summary of what is known about how PTHs stimulate bone growth. The controversial bone anabolic activities of the cholesterol-lowering lipophilic statins are also described, and mechanisms by which they may stimulate bone growth are presented. Finally, evidence is presented for the body's "fat-o-stat" cytokine--leptin--indirectly restraining bone growth via a hypothalamic factor, while at the same time serving as a local PTH-like autocrine/paracrine stimulator of osteoblast activity, as well as an inhibitor of osteoclast generation.
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Affiliation(s)
- James F Whitfield
- Institute for Biological Sciences, National Research Council of Canada, Montreal Road Campus, Building M-54, Ottawa, Ontario K1A 0R6, Canada.
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169
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Whitfield JF, Morley P, Willick GE. Bone growth stimulators. New tools for treating bone loss and mending fractures. VITAMINS AND HORMONES 2003; 65:1-80. [PMID: 12481542 DOI: 10.1016/s0083-6729(02)65059-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In the new millennium, humans will be traveling to Mars and eventually beyond with skeletons that respond to microgravity by self-destructing. Meanwhile in Earth's aging populations growing numbers of men and many more women are suffering from crippling bone loss. During the first decade after menopause all women suffer an accelerating loss of bone, which in some of them is severe enough to result in "spontaneous" crushing of vertebrae and fracturing of hips by ordinary body movements. This is osteoporosis, which all too often requires prolonged and expensive care, the physical and mental stress of which may even kill the patient. Osteoporosis in postmenopausal women is caused by the loss of estrogen. The slower development of osteoporosis in aging men is also due at least in part to a loss of the estrogen made in ever smaller amounts in bone cells from the declining level of circulating testosterone and is needed for bone maintenance as it is in women. The loss of estrogen increases the generation, longevity, and activity of bone-resorbing osteoclasts. The destructive osteoclast surge can be blocked by estrogens and selective estrogen receptor modulators (SERMs) as well as antiosteoclast agents such as bisphosphonates and calcitonin. But these agents stimulate only a limited amount of bone growth as the unaffected osteoblasts fill in the holes that were dug by the now suppressed osteoclasts. They do not stimulate osteoblasts to make bone--they are antiresorptives not bone anabolic agents. (However, certain estrogen analogs and bisphosphates may stimulate bone growth to some extent by lengthening osteoblast working lives.) To grow new bone and restore bone strength lost in space and on Earth we must know what controls bone growth and destruction. Here we discuss the newest bone controllers and how they might operate. These include leptin from adipocytes and osteoblasts and the statins that are widely used to reduce blood cholesterol and cardiovascular damage. But the main focus of this article is necessarily the currently most promising of the anabolic agents, the potent parathyroid hormone (PTH) and certain of its 31- to 38-aminoacid fragments, which are either in or about to be in clinical trial or in the case of Lilly's Forteo [hPTH-(1-34)] tentatively approved by the Food and Drug Administration for treating osteoporosis and mending fractures.
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Affiliation(s)
- James F Whitfield
- Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, Canada K1A 0R6
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170
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Marcus R, Wang O, Satterwhite J, Mitlak B. The skeletal response to teriparatide is largely independent of age, initial bone mineral density, and prevalent vertebral fractures in postmenopausal women with osteoporosis. J Bone Miner Res 2003; 18:18-23. [PMID: 12510801 DOI: 10.1359/jbmr.2003.18.1.18] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In a recent study of women with postmenopausal osteoporosis, treatment with teriparatide for a median of 19 months increased bone mineral density and decreased the risk of vertebral and nonvertebral fractures. Using the same cohort, the current study evaluated the relationship between these therapeutic effects and the patient's baseline age, vertebral bone mineral density, and prevalent vertebral fractures. In women over 65 years of age, treatment resulted in a greater increase in vertebral bone mineral density than in younger women (treatment-by-age interaction, p = 0.037), but baseline age had no effect on the relative risk reduction for vertebral fractures (treatment-by-age interaction, p = 0.558). In women receiving placebo (with calcium and vitamin D), there was an inverse relationship between baseline vertebral bone mineral density and vertebral fracture risk. When compared across bone mineral density tertiles, the effects of teriparatide on the relative risk for developing new vertebral fractures and increase in vertebral bone mineral density did not differ significantly (p = 0.817 and p = 0.615, respectively). Teriparatide treatment significantly decreased vertebral fracture risk in patients with a vertebral bone mineral density T score of less than -33 or a score between -2.1 and -3.3 (p < 0.001 and p = 0.027, respectively) and showed a trend toward reduced fracture risk in the group with a T score greater than -2.1 (p = 0.115). Placebo-treated women with two or more prevalent vertebral fractures had a significantly greater risk of developing new vertebral fractures than women with zero or one prevalent vertebral fracture (p < 0.001). When compared within prevalent vertebral fracture subgroups, the effects of teriparatide on the relative risk for developing new vertebral fractures were similar. The results of this study indicate that teriparatide offers clinical benefit to patients across a broad range of age and disease severity.
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Affiliation(s)
- Robert Marcus
- The Geriatrics Research, Education, and Clinical Center, Veterans Affairs Medical Center, Palo Alto, California, USA
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171
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172
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Smock SL, Vogt GA, Castleberry TA, Lu B, Owen TA. Molecular cloning and functional characterization of the canine parathyroid hormone/parathyroid hormone related peptide receptor (PTH1). Mol Biol Rep 2002; 28:235-43. [PMID: 12153143 DOI: 10.1023/a:1015716726452] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Parathyroid hormone (PTH) is a major mediator of calcium and phosphate metabolism through its interactions with receptors in kidney and bone. PTH binds with high affinity to PTH1 and PTH2, members of the superfamily of G protein-coupled receptors. In order to clone the canine PTH1 receptor, a canine kidney cDNA library was screened using the human PTH1 receptor cDNA and two clones were further characterized. The longest clone was 2177 bp and contained a single open reading frame of 1785 bp, potentially encoding a protein of 595 amino acids with a predicted molecular weight of 66.4 kD. This open reading frame exhibits >91% identity to the human PTH1 receptor cDNA and >95% identity when the putative canine and human protein sequences are compared. Competition binding following transfection of the canine PTH1 receptor into CHO cells demonstrated specific displacement of 125I-human PTH1-34 by canine PTH1-34, human PTH1-34, and canine/human parathyroid hormone related peptide (PTHrP) 1-34. Treatment of canine PTH1 receptor transfected cells, but not mock transfected cells, with these ligands also resulted in increased levels of intracellular cAMP. In contrast, the non-related aldosterone secretion inhibiting factor 1-35 neither bound nor activated the canine PTH1 receptor. Northern blot analysis revealed high levels of PTH1 receptor mRNA in the kidney, with much lower, but detectable, levels in aorta. heart, lung, prostate, testis, and skeletal muscle. Together, these data indicate that we have cloned the canine PTH1 receptor and that it is very similar, both in sequence and in functional characteristics, to the other known PTH1 receptors.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Binding, Competitive
- CHO Cells
- Cloning, Molecular
- Cricetinae
- Cyclic AMP/metabolism
- Dogs
- Gene Expression Profiling
- Humans
- Ligands
- Molecular Sequence Data
- Organ Specificity
- Polymerase Chain Reaction
- Protein Binding
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptor, Parathyroid Hormone, Type 1
- Receptors, Parathyroid Hormone/chemistry
- Receptors, Parathyroid Hormone/genetics
- Receptors, Parathyroid Hormone/metabolism
- Sequence Homology, Amino Acid
- Transfection
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Affiliation(s)
- S L Smock
- Department of Cardiovascular and Metabolic Diseases, Pfizer Global Research and Development, Groton Laboratories Pfizer Inc, CT 06340-8003, USA.
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173
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Abstract
Osteoporosis is a major clinical problem in older women and men. Almost any bone can fracture as a result of the increased bone fragility of osteoporosis. These fractures are associated with higher health care costs, physical disability, impaired quality of life, and increased mortality. Because the incidence of osteoporotic fracture increases with advancing age, measures to diagnose and prevent osteoporosis and its complications assume a major public health concern. BMD is a valuable tool to identify patients at risk for fracture, to make therapeutic decisions, and to monitor therapy. Several other modifiable and nonmodifiable risk factors for osteoporosis have also been identified. Treatment of potentially modifiable risk factors along with exercise and calcium and vitamin D supplementation forms an important adjunct to pharmacologic management of osteoporosis. Improved household safety can reduce the risk of falls. Hip protectors have been found to be effective in nursing home population. The pharmacologic options include bisphosphonates, HRT, SERMs and calcitonin. PTH had received FDA advisory committee approval. Alendronate has been approved for treatment of osteoporosis in men, and other treatments for men are under evaluation.
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Affiliation(s)
- Manish Srivastava
- Section of Geriatric Medicine, A91 Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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174
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Marie PJ. The molecular genetics of bone formation: implications for therapeutic interventions in bone disorders. AMERICAN JOURNAL OF PHARMACOGENOMICS : GENOMICS-RELATED RESEARCH IN DRUG DEVELOPMENT AND CLINICAL PRACTICE 2002; 1:175-87. [PMID: 12083966 DOI: 10.2165/00129785-200101030-00003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Skeletal biology is a complex process involving the developmental commitment and differentiation of chondrocytes and osteoblasts which produce and mineralize cartilage and bone matrix during growth and postnatal life. Several genes are involved in controlling osteogenesis by acting on target cells in a very complex manner. Manipulation of genes in mice and studies of genetic mutations affecting the skeleton in humans have enabled the assessment of the role of transcription factors, bone matrix proteins and regulatory factors involved in the control of chondrocyte and osteoblast differentiation, and have considerably improved our understanding of the bone formation process. Clinical studies and gene polymorphism analyses suggest that the variable expression of particular genes may be linked to clinical osteoporosis. A major challenge in the future will be to develop molecularly targeted approaches to stimulating bone formation and increasing bone mass. The use of mouse strain models and transgenic animals with variable bone density may be useful to identify genetic determinants of bone mass which may serve as a basis for drug discovery and development. On the other hand, the availability of gene microarrays and other emerging genomic techniques are promising tools to identify genes that are distinctly expressed in health and disease. These technologies may also serve to test the mechanisms of action of drugs aimed at increasing bone formation. Genetic studies of the molecular signaling pathways involved in normal and pathological osteogenesis may also help to identify genes that could be targeted for therapeutic intervention. Candidate approaches include selective gene transfection in target cells and the use of drugs acting on gene promoters to selectively enhance gene expression in osteoblasts. The development of these strategies is expected not only to bring new insight into the molecular mechanisms that govern bone formation in normal and pathological situations but, in the long term, may also result in the identification of novel molecular targets for therapeutic interventions for bone formation disorders.
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Affiliation(s)
- P J Marie
- Laboratory on Osteoblast Biology and Pathology, INSERM U349, Affiliated CNRS, Hôpital Lariboisière, Paris, France.
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175
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Abstract
While antiresorptive drugs have been the cornerstone of osteoporosis therapy, anabolic drugs are an important new advance in the treatment of osteoporosis. By directly stimulating bone formation, anabolic agents might have greater potential than the antiresorptives to increase bone mass and to decrease fractures. It is also possible that the combination of an antiresorptive agent with an anabolic agent could be more potent than either agent alone. Potential anabolic therapies for osteoporosis, including fluoride, growth hormone, insulin-like growth factor-I, strontium, and parathyroid hormone, are reviewed here. Of these, parathyroid hormone has clearly emerged as the most promising treatment at this time.
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Affiliation(s)
- Mishaela R Rubin
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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176
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Tashjian AH, Chabner BA. Commentary on clinical safety of recombinant human parathyroid hormone 1-34 in the treatment of osteoporosis in men and postmenopausal women. J Bone Miner Res 2002; 17:1151-61. [PMID: 12096828 DOI: 10.1359/jbmr.2002.17.7.1151] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Armen H Tashjian
- Department of Cancer Cell Biology, Harvard School of Public Health, Boston, Massachusetts 02115, USA
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177
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Abstract
A number of agents have been shown to reduce the risk of fractures in patients with postmenopausal osteoporosis. However, the additional benefits of combination therapy as opposed to monotherapy are uncertain. We performed a MEDLINE search and reviewed the published randomized trials of agents used in combination. Combination therapy results in greater gains in bone mineral density than monotherapy and possibly greater effects on bone turnover. However, none of these studies are large enough or of sufficient duration to determine whether a greater reduction in fracture is achieved. Combination therapy has important cost implications and is likely to be associated with an increased prevalence of adverse events, reduced tolerability and a reduction in adherence. Furthermore, over-suppression of bone turnover as a result of combination antiresorptive therapy might have adverse effects on bone strength, particularly with long-term treatment. Thus, the use of combination therapy for treatment of osteoporosis cannot be recommended on the basis of currently available evidence.
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Affiliation(s)
- Juliet E Compston
- Department of Medicine, Addenbrooke's Hospital, Cambridge CB2 2QQ, UK.
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178
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Iida-Klein A, Zhou H, Lu SS, Levine LR, Ducayen-Knowles M, Dempster DW, Nieves J, Lindsay R. Anabolic action of parathyroid hormone is skeletal site specific at the tissue and cellular levels in mice. J Bone Miner Res 2002; 17:808-16. [PMID: 12009011 DOI: 10.1359/jbmr.2002.17.5.808] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The cellular and molecular events triggering the anabolic response of the skeleton to exogenous parathyroid hormone (PTH) are not well understood. Despite the numerous bone mass studies in rats, few data are available for mice. Therefore, we treated 10-week-old female intact C57BL/6J mice with human PTH(1-34) delivered subcutaneously at a dose of 40 microg/kg per day 5 days a week for 3 weeks and 7 weeks. Bone mineral density (BMD) of total bone, femur, tibia, and lumbar vertebrae was measured weekly by PIXImus. Bone turnover was examined by histomorphometry, and gene expression of bone formation and resorption markers and osteoclastogenesis regulators in the excised femur and tibia was assessed by reverse-transcription polymerase chain reaction (RT-PCR) at 3 weeks and 7 weeks. The PTH-stimulated increase in BMD was more prominent in the tibia and femur than in the lumbar vertebrae, with an anabolic effect detected within 1-2 weeks and BMD continuing to increase. The appearance of a detectable PTH-stimulated increase in BMD was slower in the lumbar vertebrae where the increase was only significant after 7 weeks of treatment. Histomorphometric analysis of the proximal tibia at both 3 weeks and 7 weeks indicated significant time-dependent increases in trabecular area, trabecular number, trabecular and cortical widths, and osteoblast and osteoid perimeters. In the lumbar vertebrae, these stimulatory effects of PTH on trabecular area, trabecular number, and cortical width were smaller and not detected until 7 weeks. PTH-stimulated increases in bone turnover were evident by increased gene expression of osteocalcin (OC), tartrate-resistant acid phosphatase (TRAP), and receptor of activator nuclear factor kappaB (NF-kappaB) ligand (RANKL) in the tibia and femur. No significant difference in gene expression was observed between the two long bone sites. In conclusion, PTH exerts an anabolic action at the tissue and cellular levels in intact mice and the magnitude and temporal pattern of this anabolic action, as assessed by densitometry and histomorphometry, are skeletal site specific.
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Affiliation(s)
- Akiko Iida-Klein
- Regional Bone Center, Helen Hayes Hospital, New York State Department of Health, West Haverstraw 10993-1195, USA
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179
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Rubin MR, Silverberg SJ. Rheumatic manifestations of primary hyperparathyroidism and parathyroid hormone therapy. Curr Rheumatol Rep 2002; 4:179-85. [PMID: 11890884 DOI: 10.1007/s11926-002-0014-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A frequent manifestation of severe primary hyperparathyroidism was the bone disease osteitis fibrosa cystica. Rarely, excess parathyroid hormone (PTH) was associated with gout and calcium pyrophosphate crystal deposition disease. Surgical cure of primary hyperparathyroidism was occasionally associated with pseudogout. Today, primary hyperparathyroidism is generally asymptomatic. Clinically overt rheumatologic and skeletal effects are mainly of historical interest. Skeletal disease is still detectable by more sensitive techniques. In certain circumstances, PTH may be protective and anabolic for the skeleton.
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Affiliation(s)
- Mishaela R Rubin
- Department of Medicine, College of Physicians & Surgeons, Columbia University, 630 W. 168th Street, New York, NY 10032, USA.
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180
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181
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Malaivijitnond S, Takenaka O, Anukulthanakorn K, Cherdshewasart W. The nucleotide sequences of the parathyroid gene in primates (suborder Anthropoidea). Gen Comp Endocrinol 2002; 125:67-78. [PMID: 11825036 DOI: 10.1006/gcen.2001.7735] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nucleotide sequences of the parathyroid (PTH) gene of 12 species of primates belonging to suborder Anthropoidea were examined. The PTH gene contains one intron that separates two exons that code the sequence of prepro and PTH, respectively. The intron of the PTH gene in Cebus apella, Callithrix jacchus, and Saguinus oedipus was 102 bp long, whereas a 103-bp intron was observed in the remaining species. Phylogenetic analysis using the nucleotide sequences of PTH revealed that these 12 species of primates of suborder Anthropoidea could be divided into two groups of the infraorder Platyrrhini (C. apella, C. jacchus, and S. oedipus) and the infraorder Catarrhini (Macaca fascicularis, Macaca fuscata, Cercopithecus aethiops, Papio hamadryas, Presbytes obscura, Hylobates lar, Pongo pygmaeus, Pan troglodytes, and Pan paniscus). The latter infraorder could be further subdivided into two subgroups belonging to the superfamily Cercopithecoidea (M. fascicularis, M. fuscata, C. aethiops, P. hamadryas, and P. obscura) and the superfamily Hominoidea (H. lar, P. pygmaeus, P. troglodytes, and P. paniscus). The deduced amino acid sequences of PTH gene between 12 species of nonhuman primates and human revealed no amino acid substitution in mature PTH among orangutans, chimpanzees, and humans. The results indicated that the PTH gene is very conserved among primates, especially between great apes and humans. The apes are the most suitable animals to be used for studying the bone metabolism and applying the knowledge to clinical use in humans.
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182
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Whitfield JF, Morley P, Willick GE. Parathyroid Hormone, Its Fragments and Their Analogs for the Treatment of Osteoporosis. ACTA ACUST UNITED AC 2002; 1:175-90. [PMID: 15799210 DOI: 10.2165/00024677-200201030-00005] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The susceptibility to traumatic fracturing of osteopenic bones, and the spontaneous fracturing of osteoporotic bones by normal body movements caused by the microstructural deterioration and loss of bone, are currently treated with antiresorptive drugs, such as the bisphosphonates, calcitonin, estrogens, and selective estrogen receptor modulators. These antiresorptive agents target osteoclasts and, as their name indicates, reduce or stop bone resorption. They cannot directly stimulate bone formation, increase bone mass above normal values in ovariectomized rat models, or improve microstructure. However, there is a family of agents - the parathyroid hormone (PTH) and some of its fragments and their analogs - which directly stimulate bone growth and improve microstructure independently from impairing osteoclasts. These drugs are about to make their clinical debut in treating patients with osteoporosis and, probably not too far in the future, for accelerating fracture healing. They stimulate osteoblast accumulation and bone formation in three ways via signals from the type 1 PTH/PTH-related protein (PTHR1) receptors on proliferatively inactive preosteoblasts, osteoblasts, osteocytes and bone-lining cells. The receptor signals shut down the proliferative machinery in preosteoblasts and push their maturation to osteoblasts, cause the osteoblastic cells to make and secrete several factors that stimulate the extensive proliferation of osteoprogenitors without PTHRI receptors, stimulate the reversion of bone-lining cells to osteoblasts, and extend osteoblast lifespan and productivity by preventing them from suicidally initiating apoptosis. The first of the PTHs to reach the clinic will be teriparatide [recombinant human (h)PTH-(1-34)], which was recommended for approval in 2001 by the US Food and Drug Administration Endocrinology and Metabolic Drugs Advisory Committee for the treatment of postmenopausal osteoporosis. Teriparatide has been shown to considerably increase cancellous and cortical bone mass, improve bone microstructure, prevent fractures and thus provide benefits that cannot be provided by current antiresorptive drugs, when administered subcutaneously at a daily dose of 20 microg for no longer than 2 years to patients with osteoporosis.
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Affiliation(s)
- James F Whitfield
- Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, Canada.
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183
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Trafton PG. What's new in orthopaedic surgery. J Am Coll Surg 2001; 193:641-8. [PMID: 11768681 DOI: 10.1016/s1072-7515(01)01103-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- P G Trafton
- Department of Orthopaedic Surgery, Brown University and Rhode Island Hospital, Providence, USA
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184
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Abstract
The aim of treating osteoporosis is to restore bone strength by increasing its mass and reconstructing its architecture. Antiresorptive drugs reduce bone remodeling, allowing more complete secondary mineralization of the existing bone; the mass, macro- and microarchitecture of the bone remains unchanged. Anabolic agents have the potential to achieve this goal. Parathyroid hormone (PTH) is famous for its catabolic actions. Its anabolic effects, known by a select few over 70 years ago, are finally being appreciated. There is widely reproduced and compelling evidence in a range of species made osteoporotic by gonadectomy that intermittent PTH administration restores bone strength by stimulating new bone formation on the periosteal (outer) and endosteal (inner) bone surfaces, enlarging bone diameter, thickening the cortices and existing trabeculae, and perhaps increasing trabecular numbers and their connectivity.
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Affiliation(s)
- E Seeman
- Austin and Repatriation Medical Centre, University of Melbourne, VIC., Australia.
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