Modulation of articular chondrocyte proliferation and anionic glycoconjugate synthesis by glucosamine (GlcN), N-acetyl GlcN (GlcNAc) GlcN sulfate salt (GlcN.S) and covalent glucosamine sulfates (GlcN-SO4).

OBJECTIVES: To investigate, in chondrocyte cultures under conditions for maximizing responses in proliferation and proteoglycan (PG) synthesis, the effects of glucosamine hydrochloride (GlcN.HCl) and glucosamine sulfate (GlcN.S) salts, N-acetyl glucosamine (GlcNAc), and covalently substituted GlcN-X,Y,Z(SO(4))(n) (general formula). METHODS: Bovine articular chondrocytes (BAC) were studied under anchorage-independent (AI, alginate beads) and anchorage-dependent (AD, plastic surface) conditions. Differentiation markers were evaluated (e.g., cartilage-specific (V+C)(-) fibronectin). Varying concentrations of GlcN.HCl, GlcN.S, GlcNAc and GlcN sulfated at positions -2, -3, -6, (-2,3), (-3,6) and (-3,4,6), were tested. Cell proliferation, DNA synthesis and [(35)S]-sulfate incorporation into newly synthesized PG were determined. RESULTS: Increasing GlcN.HCl or GlcN.S concentrations gave decreasing net PG synthesis. Compounds showed more pronounced effects in AD cultures (expressing the V(-)C(+) fibronectin isoform) compared to AI cultures ((V+C)(-) isoform). Addition of GlcN.HCl or GlcN.S gave a concentration-dependent decrease in BAC proliferation, partially prevented by glucose (Glc). GlcNAc was not inhibitory. Addition of GlcN-2-SO(4) or GlcN-2,6-diSO(4) did not affect proliferation or DNA synthesis. The other GlcN-sulfates gave varying inhibitory effects, which for GlcN-3-SO(4) were reversed by inosine. CONCLUSIONS: The free amino group of GlcN seems responsible for inhibition of chondrocyte proliferation and PG synthesis. These effects were greater under higher concentrations of GlcN in AD vs AI conditions. GlcN.HCl behaves similarly to GlcN.S, but differential effects with GlcN-X,Y,Z(SO(4))(n) isomers were observed. Acetylation or sulfation of the GlcN amino group reverses or partially reverses, respectively, anti-proliferative effects of GlcN. Sulfation of GlcN, at positions 3 and 6 results in complex effects on AC proliferation and PG synthesis.

Prevalence of and factors associated with glucosamine use in Canada.

OBJECTIVE: Glucosamine is commonly used for the treatment of osteoarthritis, and its use is increasing in the general population. The Canadian Multicentre Osteoporosis Study (CaMos) provided an opportunity to examine the prevalence of glucosamine use across age and gender groups, and to assess the factors associated with its use. METHOD: CaMos is a random, population-based sample of 9423 Canadians. Baseline assessments took place in 1996-1997 and the 5-year follow-up assessments in 2001-2002. The primary outcome of this analysis was glucosamine use at year 5. Prevalence estimates were age- and sex-standardized to the Canadian population. A number of factors potentially associated with glucosamine use were identified from the literature. Multivariable logistic regression was used to identify variables associated with glucosamine use. RESULTS: At 5 years, complete data were available for 7652 of the original 9423 participants (81.2%). For men, glucosamine use increased from 0.9% to 4.7% (weighted values), and for women, it increased from 1.3% to 8.2%. Glucosamine use was higher among older participants, those living in western Canada, and those with arthritis, back pain, higher calcium intake from supplements, physical activity and prior glucosamine use. CONCLUSIONS: Glucosamine use increased substantially over 5 years, and its use is associated with a number of factors. Some may use glucosamine to manage pain and symptoms of arthritis and back pain, while others use it as a preventive measure to maintain health.