CHECK OUT THIS SUPER INTERESTING PRESENTATION ON ALL ABOUT BONE ACTIVITY IN CLINICAL BIOCHEMISTRY BASIS. HERE YOU WILL GET COMPLETE DESCIPTION ON HOW THE BONE DISSORDERS HAPPENING AND FACTORS TO BE GOVERNED. ENJOY LEARNING.

1. CLINICAL BIOCHEMISTRY AND BONES
~ DETAILED STUDY

2. AARATHILFA G
IST M.SC. ADVANCED
BIOCHEMISTRY
Submitted by-

3. BONES
 Ossification – Process of bone formation by
osteoblasts
 Growth starts from 6th week after fertilization in
an embryo till 25 years of age
 Grows in thickness throughout life, but after 25,
ossification functions primarily in bone
remodelling and repair

4. REQUIRMENT
For healthy and normal growth of bones, proper
amount of:
 Vitamin D,C and A
 Minerals like calcium, phosphorus and
magnesium
 Hormones like PTH, GH and Calcitonin
are required

6. ENZYMOLOGY
 Clinical biology - body fluid, predominantly,
blood as most of the disease conditions are
diagnosed using the ↑ed or ↓ed levels of
enzymes in serum/plasma.
 Plasma functional enzymes are secreted actively
into plasma whereas plasma non- functional
enzymes are increased during disease conditions

7. ALKALINE PHOSPHATASE
~ BONE PROFILE

8. ALP
 EC. 3.1.3.1
 Non-specific enzyme hydrolysing aliphatic, aromatic or
heterocyclic compounds.
 Optimum pH – between 9 and 10
 Activator – magnesium and manganese
 Constituent ion – zinc; produced by osteoblasts of bone, and is
associated with calcification process
 Location – cell membranes (ecto-enzyme)
 Function – associated with transport mechanisms in liver, kidney
and intestinal mucosa
 Sialic acid content in ALP iso-enzyme makes it iso-forms due to
its synthesis during post- translational modification

9. CLINICAL MANIFESTATION
 Normal serum value : 40 – 125 U/L
 Upper normal in children is more, due to ↑ed osteoblastic
activity
 Mild ↑ during pregnancy, due to placental iso-enzyme
production
 Moderate ↑(2 to 3 times) during hepatic disease such as
infective hepatitis, alcoholic hepatitis or hepato cellular
carcinoma; Hodgkin’s lymphoma; congestive cardiac failure
or ulcerative colitis
 Very high level(10-12 times upper limit) during extrahepatic
obstruction (obstructive jaundice) or cholestasis
 Drastically high level(10-25 times upper limit) during bone
diseases such as Paget’s disease, rickets, osteomalacia,
osteoblastoma, hyperparathyroidism

10. SOURCES FOR HEALTHY BONE
Calcium
ExerciseVitamin D

11. ROLE OF VITAMIN D AND BONE DISSORDER

12. CALCITRIOL (1,25- DHCC)
 Biological active form of vitamin D
 7-dehydrocholesterol , an intermediate in cholesterol
biosynthesis, on exposure to sun light is converted to
cholecalciferol (vitamin D3) in the skin. On several
hydroxylation, calcitriol(1,25-
DiHydroxyCholeCalciferol) is synthesised
 Regulates the plasma levels of calcium and phosphate
 Acts at 3 different level – intestine, kidney and bone.

13. RICKETS
 Due to deficiency of vitamin D in children
 Derived from an old English word ‘wrickken’ means
twist.
 Characterized by bone deformities due to incomplete
mineralization, resulting in soft and pliable bones.
Weight bearing bones are bent to form bow-legs.
 plasma level of calcitriol is decreased and ALP is
elevated

15. OSTEOMALACIA
 Due to deficiency of vitamin D in adult (adult
rickets)
 Derived from Greek :osteon- bone; malakia –
softness
 Demineralization of bones occurs, increasing
their susceptibility to fracture
 Vitamin D is called as antirachitic vitamin

17. ROLE OF CALCIUM AND BONE DISSORDER

18. PARATHYROID HORMONE (PTH)
 Causes demineralization of bone, carried out by
osteoclasts, by stimulating ↑ed activity of enzyme
pyrophosphatase and collagenase resulting in
bone reabsorption
 this leads to an increase in the blood Ca level
 Thus blood calcium level is maintained
associated with alterations in PTH

19. RENAL OSTEODYSTROPHY
 Observed in patients with chronic renal failure
or with damage to renal tissues causing
impairment in the synthesis of calcitriol
 Thus renal rickets is mainly due to ↓ed synthesis
of calcitriol in kidney
 This does not respond to vit D, thus called as
vitamin D resistant rickets
 Treated by administration of calcitriol

21. OSTEOPOROSIS
 Characterized by demineralization of bone
resulting in progressive loss of bone mass
 Generally, elderly people (60+ yrs)of both sexes
are at the risk for osteoporosis
 But predominantly occurs in post –menopausal
women.
 This results in frequent bone fractures

23.  The ability to produce calcitriol from vit D is ↓ed with age,
particularly in postmenopausal women
 Immobilized or sedentary individuals tend to decrease bone
mass while those on regular exercise tend to increase bone
mass
 Deficiency of sex hormone(women) has been implicated in
the development of osteoporosis
 Estrogen administration along with calcium
supplimentation (in combination with vit D)to
postmenopausal women reduces the risk factor
 Higher dietary intake of Ca (<1.5g/day) is recommended for
elderly people

25. OSTEOPETROSIS
 Known as marble bone disease
 Characterized by ↑ed bone density, due to
inability to resorb bone
 Mostly observed in association with renal
tubular acidosis ( due to defect in the enzyme
carbonic anhydrase) and cerebral calcification

27. ROLE OF REMODELLING AND BONE DISSORDER

28. PAGET’S DISEASE
 A chronic condition which interferes with the
body’s normal bone remodelling process
 This can cause the affected bones to become
fragile and misshapen
 Most commonly occurs in pelvis, skull, spine and
legs

30. Complications includes:
 Age : 40+yrs
 Sex: Men are affected more
 Family history
 Fractures and deformities(Lathyrism)
 Osteoarthritis
 Neurological problems
 Heart failure
 Bone carcinoma
 Hearing loss

31. Single site of bone is affected –
monostotic paget’s disease
Multiple sites of bone are affected
– polystotic paget’s disease
Bisphosphonate – medication also
used in osteoporosis- are the
mainstay of treatment
In several cases, surgery may be
necessary