Chondroitin

What is Chondroitin?

Chondroitin sulfate is a sulfated glycosaminoglycan (GAG) composed of a chain of alternating sugars (N-acetylgalactosamine and glucuronic acid). It is usually found attached to proteins as part of a proteoglycan. Chondroitin sulfate is an important structural component of cartilage and provides much of its resistance to compression. Along with glucosamine, chondroitin sulfate has become a widely used dietary supplement for treatment of osteoarthritis.

Chondroitin Dosage

The dosage of oral chondroitin used in human clinical trials is 800–1,200 mg per day.  Pharmacokinetic studies performed on humans and experimental animals after oral administration of chondroitin sulfate revealed that it can be absorbed orally.  The bioavailability of chondroitin sulfate ranges from 15% to 24% of the orally administered dose

How does Chondroitin Works on the Joint?

The benefit of chondroitin sulfate in patients with osteoarthritis is likely the result of a number of effects including its anti-inflammatory activity, the stimulation of the synthesis of proteoglycans and hyaluronic acid, and the decrease in catabolic activity of chondrocytes inhibiting the synthesis of proteolytic enzymes, nitric oxide and other substances that contribute to damage cartilage matrix and cause death of articular chondrocytes. A recent review summarizes data from relevant reports describing the biochemical basis of the effect of chondroitin sulfate on osteoarthritis articular tissues1. The rationale behind the use of chondroitin sulfate is based on the belief that osteoarthritis is associated with a local deficiency in some natural substances, including chondroitin sulfate.

Recently, new mechanisms of action have been described for chondroitin sulfate. In an in vitro study, chondroitin sulfate reduced the IL-1β-induced nuclear factor-kB (Nf-kB) translocation in chondrocytes2. In addition, chondroitin sulfate has recently shown a positive effect on osteoarthritic structural changes occurred in the subchondral bone3.

Chondroitin Osteoarthritis Research

Russian researchers reported intervention with chondroitin sulfate in patients with hip OA could protect cartilage, slow disease progression and aid in pain management.4  Pain management was also the primary efficacy criteria in a 24-week, randomized, placebo controlled study conducted at Rangueil University Hospital, Toulouse, France, in which patients with knee OA (n=307) received 1 g/d chondroitin sulfate for six months. 5  While there was no significant difference in biomarkers between the groups, chondroitin was slightly more effective for pain management and quality of life scores. Another group of French researchers divided a crosssectional observational study, which found long-term users of chondroitin sulfate had a significantly lower current and long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) and analgesics. 6

In fact, a 2007 risk assessment on the use of glucosamine and chondroitin sulfate noted: “A large body of human and animal research suggests that oral intakes of these ingredients, either alone or in combination, reduces joint pain and improves mobility in persons with osteoarthritis. … The observed safe level (OSL) risk assessment method indicates that the evidence strongly supports safety at intakes up to 2,000 mg/d for glucosamine and 1,200 mg/d for chondroitin sulfate.” 7

References:
1. Monfort J, Pelletier J-P, Garcia-Giralt N, Martel-Pelletier J. Biochemical basis of the effect of chondroitin sulfate on osteoarthritis articular tissues. Ann Rheum Dis 2007; doi:10.1136/ard.2006.068882 .
2  Jomphe C, Gabriac M, Hale TM, Heroux L, Trudeau LE, Deblois D, Montell E, Verges J, du Souich P. Chondroitin Sulfate Inhibits the Nuclear Translocation of Nuclear Factor-kappaB in Interleukin-1beta-Stimulated Chondrocytes. Basic Clin Pharmacol Toxicol. 2007 Nov 5
3.  Kwan Tat S, Pelletier JP, Verges J, Lajeunesse D, Montell E, Fahmi H, Lavigne M, Martel-Pelletier J. Chondroitin and glucosamine sulfate in combination decrease the pro-resorptive properties of human osteoarthritis subchondral bone osteoblasts: a basic science study. Arthritis Res Ther. 2007 Nov 9;9(6):R117
4. Shmidt EI et al. “[Long-term efficacy and safety of chondroitin sulphate (structum, France) in patients with coxarthrosis][Article in Russian].” Ter Arkh. 2007;79(1):65-7.
5. Mazières B et al. “Effect of chondroitin sulphate in symptomatic knee osteoarthritis: a multicentre, randomised, double-blind, placebo-controlled study.” Ann Rheum Dis. 2007 May;66(5):639-45.
6. Lagnaoui R et al. “Less use of NSAIDs in long-term than in recent chondroitin sulphate users in osteoarthritis: a pharmacy-based observational study in France.” Therapie. 2006 Jul-Aug;61(4):341-6.
7. Hathcock JN, Shao A. “Risk assessment for glucosamine and chondroitin sulfate.” Regul Toxicol Pharmacol. 2007 Feb;47(1)78-83.