Osteoporosis: In postmenopausal women with low levels of estrogen By Jeffrey Brimmer Bio475 Seminar

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Osteoporosis In postmenopausal women with low
levels of estrogen By Jeffrey Brimmer
Bio-475 SeminarDr. Lin

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What is bone?

• Bone is the living tissue that supports our
  muscles, protects our organs, and stores most of
  the calcium in the body.

The McMillan Visual Dictionary, McMillan
Publishing Company, 1992
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What are osteoblasts and osteoclasts?

• An osteoblast is a mononucleate cell that is
  responsible for the formation of bone.
• An osteoclast is a bone cell that removes bones
  mineralized matrix in a process called bone
  resorption.

Kölliker
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What is osteoporosis?

• It a disease of the bones in which bone mineral
  density is reduced and the micro architecture is
  altered.
• There is an imbalance between bone resorption and
  bone formation.

National Institute of Arthritis and
Musculoskeletal and Skin Diseases
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Causes of osteoporosis

• Osteoporosis is caused by the break down of bone
  density because osteoblasts are not forming bone
  fast enough or bone resorption is not taking
  place.
• There is a lack of glucocorticoid hormone to
  increase osteoclast activity.
• A lack of exercise could also lead to
  osteoporosis.
• In women, a lack of estrogen increases bone
  resorption and decreases the deposit of bone.
• The lack of vitamin D and calcium in a persons
  diet can lead to impaired bone deposition.
• With a lack of calcium in the blood more
  parathyroid hormone is released which increases
  bone resorption.

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Menopause

• The permanent physiological stop of the menstrual
  cycle in women.
• Triggered by the deterioration or shut down of
  the ovaries production of estrogen.
• One of estrogens main functions is to reduce bone
  resorption and increases the formation of new
  bone.

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Epidemiology of osteoporosis

• Affects both men and women, but is especially
  seen in women.
• Estimated that one in three women have
  osteoporosis.
• Most prevalent in non-Hispanic white, and Asian
  women.
• Hip fractures, vertebral factures, and distal
  radius fractures are among the most common
  fractures seen in people with osteoporosis.

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Possible treatments of osteoporosis

• Hormone replacement therapy in women to increase
  estrogen levels.
• Bisphosphonates are drugs that inhibit osteoblast
  action and resorption of bone.
• Teriparatide is a recombinant form of parathyroid
  hormone.
• Strontium ranelate is drug taken orally.

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References

• Biller, B.M., V. Saxe, D.B. Herzog, D.I
  Rosenthal, S. Holzman, and A. Klibanski. 1989.
  Mechanisms of osteoporosis in adult and
  adolescent women with anorexia nervosa. The
  Journal of clinical endocrinology and metabolism.
  68 548-554. Retrieved 19 Sept 2007.
• http//jcem.endojournals.org/cgi/content/abstract/
  68/3/548
• Falhammar, H, H. Filipsson, G. Holmdahl, P.O.
  Janson, A. Nordenskjöld, K. Hagenfeldt, and M.
  Thorén. 2007. Fractures and bone mineral density
  in adult women with 21-hydroxylase deficiency.
  The Journal of clinical endocrinology and
  metabolism. 10 1210. Retrieved 19 Sept 2007.
  http//jcem.endojournals.org/cgi/rapidpdf/jc.2007-
  0744v1
• Guardia, G., N. Parikh, T. Eskridge, E.
  Phillips, G. Divine, and D.S. Rao. 2007.
  Prevalence of vitamin D depletion among subjects
  seeking advice on osteoporosis a five-year
  cross-sectional study with public health
  implications. Osteoporosis international. 10
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• Lewiecki, E.M. 2007. Long dosing intervals in the
  treatment of postmenopausal osteoporosis. Current
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