Clinical and Technical Review - Tecomedical

2
Bone turnover Biomarker in
Osteoporosis
Diagnosis of metabolic bone diseases can be established
by measuring bone mineral density (BMD) at the hips or spine.
However, BMD is a static measure of bone composition,
reflecting its history. A baseline BMD value does not offer
any prediction of future bone loss or response to therapy.
Moreover, since biochemical bone marker reflect the wholebody
rates of bone turnover, the combined measurement of
bone marker and BMD provides more information on the
overall bone loss than BMD measurement at specific skeletal
sites alone.
The increasing number of drugs available for treatment of
osteoporosis and other bone diseases requires the use of
more rapid and predictive methods to assess therapy efficacy.
While detectable and significant changes in BMD take 18 to
24 months to develop, bone turnover marker have been
shown to detect changes in bone tissue within 3-6 months
after starting anti-resorptive therapy. Therefore, measurement
of bone turnover marker is increasingly recommended
as a key component of therapy management: to rapidly
identify therapy responders and non-responders, to assess
therapy efficacy and to determine the optimal therapy and
dose of treatment.
Bone marker are intended for use as an
aid in:
• management of postmenopausal osteoporosis and
Paget’s disease;
• monitoring of postmenopausal women on hormonal
or bisphosphonate therapy;
• prediction of skeletal response to hormonal therapy
in postmenopausal women.
• Detection and monitoring of Bone metastasis.
Biomarker and Cartilage Destruction
Degenerative joint disease such as osteoarthritis (OA) and
rheumatoid arthritis (RA) are major causes of disability and
impaired quality of life among the elderly. Despite better
understanding of the underlying pathomechanisms, current
clinical practice for diagnosing these diseases mainly relies
on symptom assessment, which has limited sensitivity and
specificity. By the time radiological techniques can reveal
specific sign, the disease has advanced to a late phase with
pronounced structural damage, when the only therapeutical
option remaining is joint replacement. As marker provide a
dynamic measure of current degradation rate in contrast to
radiological investigations, they allow a rapid determination
of the therapeutic effects, and they may also be used for
selecting the therapies and drug dose, which are most efficient.
In the lack of established diagnostic methods allowing
the detection of cartilage degradation, early diagnosis
and disease monitoring remain a major challenge of health
care professionals.
Therefore Biochemical marker for Cartilage degradation and
synthesis are helpful for the management of Rheumatoid
Arthritis and Osteoarthritis.
Biomarker for diagnosing skeletal
metastases
Cancers have the ability to metastasize to organs distant
from the site of the primary tumor. Breast, prostate,
and lung cancer are primary tumors that most frequently
metastasize to the skeleton. The chronic presence of bone
metastasis often results in complete pathologic remodeling
of the affected bone compartment, making affected bones
vulnerable to several complications. Such complications
include pathologic fractures, spinal cord compression,
hypocalcemia, and severe bone pain. All reducing quality of
life and worsening prognosis. Therefore, early diagnosis and
adequate treatment of bone metastasis is critically important
for the clinical management of cancer patients.
Emerging evidence suggests that biomarker of bone
turnover carry notable potentials to become useful
diagnostic tools for the diagnosis of bone metastases.
The study by Leeming et al was sought to assess the
relative use of eight biomarker for the detection of bone
metastases in cancer forms frequently spreading to the skeleton.
Participants were 161 patients with either breast, prostate,
or lung cancer. The presence and extent of
bone metastases was assessed by imaging techniques
(computer tomography and/or magnetic resonance
imaging) and Technetium-99m scintigraphy. Number of
bone metastases was recorded, and the skeletal load was
graded, as previously proposed by Soloway. The Serum
or urinary level of the bone resorption marker (alpha-CTX,
beta-CTX, NTX, and ICTP), formation marker (BSAP),
and osteoclastogenesis marker (osteoprotegerin, RANKL,
and TRAP5b) was measured by commercially available
immunoassays. There was a uniform pattern of significantly
increased levels of the resorption marker in patients with
bone metastases compared with those without.
The relative responsiveness of marker was calculated to
obtain insights into the relative sensitivity of the different
marker to signal skeletal involvement. The plot demonstrates
a trend toward greater relative increases in the level of the
urine alpha-CTX and serum BSAP marker compared with
other marker; differences becoming more evident with
increasing Soloway score.