IGF-1 (insulin-like growth factor) is a protein produced by the liver in response to growth hormone stimulus. For this reason, IGF-1 is often used to assess the body's natural biochemical source for proper bone, muscle and tissue development. Both IGF-1 and growth hormone levels usually decline with age. One important key in effectively preventing and treating osteoarthritis, is establishing a healthy balance of IGF-1.

Numerous clinical studies suggest that IGF-1 works to protect and repair cartilage tissue. 1-3 One researcher has cited this protein as "the major anabolic mediator for articular cartilage."4 This regenerative effect of IGF-1 is believed to offset the damage inflicted by reactive immune mediators, such as cytokines, to the cartilage. Thus diminished serum levels have been discovered in patients with osteoarthritis as compared with controls, 5, 6 although one study found that the correlation with these low levels was age-related.7

Within the arthritic joint itself, dysfunctional mechanisms involving IGF-1 may manifest in a variety of ways. Specific genotypes of the IGF-1 gene are significantly associated with the presence of osteoarthritis.8 The most damaged osteoarthritic tissue shows a heightened genetic expression for increased sensitivity to IGF-1 receptor messages. 9

It may be as a response to progressive cartilage degradation that IGF-1 levels within the damaged joint itself are much higher than they are in normal cartilage tissue.10,11 However, some investigators have speculated that despite these increased local levels, the chondrocytes--cartilage cells--are unresponsive to these elevations due to increased binding of IGF-1 to binding proteins, rendering IGF-1 biologically unavailable.12 Because high bone density is associated with increased risk of osteoarthritis, however, large excess of growth hormone in the body is also thought to exert a detrimental effect on development of osteoarthritis.13

IGF-1 Assessment provides important information about the body's levels of this crucial hormonal mediator in osteoarthritis, and also helps assess the general functioning integrity and homeostasis of the nervous system.

References
1 Bellometti S, Giannini S, Sartori L, Crepaldi G. Cytokine levels in osteoarthritis patients undergoing mud bath therapy. Int J Clin Pharmacol Res 1997;17(4):149-53.

2 Keyszer GM, Heer AH, Kriegsmann J, Geiler T, Keysser C, Gay RE, Gay S. Detection of insulin-like growth factor I and II in synovial tissue specimens of patients with rheumatoid arthritis and osteoarthritis by in situ hybridization. J Rheumaol 1995;22(2):275-281.

3 Trippel SB. Growth factor actions on articular cartilage. J Rheumatol Suppl 1995;43:129-32.

4 Olney RC, Tsuchiya K, Wilson DM, Mohtai M, Maloney WJ, Schurman DJ, Smith RL. Chondrocytes from osteoarthritic cartilage have increased expression of insulin-like grwoth factor I (IGF-1) and IGF-binding protein-3 (IGFBP-3) and - 5, but not IGF-II or IGFBP-4. J Clin Endocrinol Metab 1996;81(3):1096-103.

5 Moskowitz RW, Boja B, Denko CW. The role of growth factors in degernative joint disorders. J Rheumtol Suppl 1991;27:147-8.

6 Denko CW, Boja B, Moskowitz RW. Growth promoting peptides in osteoarthritis: insulin, insulin-like growth factor-1, growth hormone. J Rheumatol 1990;17(9):1217-21.

7 Hochberg MC, lehtbridge-Cejku M, Scott WW Jr, Reichle R, Plato CC, Tobin JD. Serum levels of insulin-like growth factor in subjects with osteoarthritis of the knee. Data form the Baltimore Longitudinal Study of Aging. Arthritis Rheum 1994;37(8):1177-1180.

8 Meulenbelt I, Bijkerk C, Meidema HS, Breeveld FC, Hofman A, Valkenburg HA, et. al. A genetic association study of the IGF-1 gene and radiological osteoarthritis in a population-based cohort sutdy (the Rotterdam Study). Ann Rheum Dis 1998;57(6):371-4.

9 Middleton J, Manthey A, Tyler J. Insulin-like growth factor (IGF-1) receptor, IGF-1, interleukin-1 beta (IL-1 beta), and IL-6 m RNA expression in osteoarthritic and normal human cartilage. J Histochem Cytochem 1996;44(2):133-141.

10 Schneiderman R, Rosenberg N, Hiss J, Lee P, Liu F, Hintz RL, Maraoudas A. Concentration and size distribution of insulin-like growth factor-1 in human normal and osteoarthritic synovial fluid and cartilage. Arch Biochem Biophys 1995;324(1):173-88.

11 Lloyd ME, Hart DJ, Nandra D, McAlindon TE, Wheeler M, Doyle DV, Spector TD. Relation between insulin-like growth factor-I concentrations, osteoarthritis, bone density, and fractures in the general population: the Chingford study. Ann Rheum Dis 1996;55(12):870-4.

12 Martel-Peletier J, Di Battista JA, Lajeunesse D, Pelletier JP. IGF/IGFBP in carilage and bone in osteoarthritis pathogenesis. Inflamm Res 1998;47(3):90-100.

13 Bouillon R. Growth hormone and bone. Horm Res 1991;36 Suppl 1:49-55.

All lab tests can be done through the mail in the privacy of your own home, except blood tests, we send you to a lab to have your blood drawn for these. After you pay for the test we mail you the kit, the results take two weeks, the test results will be mailed to us and we will call you to go over the results, its that easy! All tests include the consultation for the report of findings.

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