FROM:
Alternative Medicine Review 1999 (Jun); 4 (3): 193–195 ~ FULL TEXT
Glucosamine sulfate's role in halting or reversing joint
degeneration appears to be directly due to its ability to act as an essential
substrate for, and to stimulate the biosynthesis of, the glycosaminoglycans
and the hyaluronic acid backbone needed for the formation of the proteoglycans
found in the structural matrix of joints. Successful treatment of osteoarthritis
must effectively control pain and should slow down or reverse the progression
of the degeneration. Biochemical and pharmacological data combined with
animal and human studies demonstrate that glucosamine sulfate is capable
of satisfying both of these criteria.
Introduction
Glucosamine is the most fundamental building block required
for biosynthesis of the classes of compounds including glycolipids, glycoproteins,
glycosaminoglycans (formerly called mucopolysaccharides), hyaluronate,
and proteoglycans. As a component of these macromolecules, glucosamine
has a role in the synthesis of cell membrane lining, collagen, osteoid,
and bone matrix. Glucosamine is also required for the formation of lubricants
and protective agents such as mucin and mucous secretions.
Pharmacokinetics
In humans, about 90 percent of glucosamine, administered
as an oral dose of glucosamine sulfate, is absorbed from the digestive
tract. [1] After an oral
dose, glucosamine concentrates in the liver, where it is either incorporated
into plasma proteins, degraded into smaller molecules, or utilized for
other biosynthetic processes. [1]
Elimination of glucosamine is primarily through the urine, with a small
amount of glucosamine or its derivatives eliminated in the feces. [2, 3]
Mechanism of Action
Glucosamine sulfate is capable of stimulating proteoglycan
synthesis, inhibiting the degradation of proteoglycans, and stimulating
the regeneration of experimentally-induced cartilage damage. [4, 5]
Some experts also believe glucosamine sulfate might promote the incorporation
of sulfur into cartilage. [6]
Clinical Research on Osteoarthritis
The primary therapeutic use of glucosamine sulfate has
been in the treatment of degenerative diseases of the joints. Although
many of the available studies have compared glucosamine sulfate to placebo,
in the trials where glucosamine sulfate has been compared to NSAIDs, long-term
reductions in pain are greater in patients receiving glucosamine sulfate. [7–11]
Symptoms such as articular pain, joint tenderness, and
swelling often improve following a 6-8 week period of oral administration
of glucosamine sulfate. [7–13] For
most individuals, an expectation of a reduction in symptoms of from 50-70
percent is reasonable. [7]
Improvements secondary to glucosamine sulfate therapy generally are sustained
six to 12 weeks following cessation of the treatment regimen. [12]
For arthritis of the knee, evidence suggests that about
60 percent of patients will have a good to excellent response to this intervention,
while an additional 35 percent will have a more moderate benefit. Preliminary
evidence suggests patients with arthritis of the shoulder or elbow respond
the best to glucosamine sulfate (about 75 percent judged as good and only
one percent judged as insufficient), while polyarticular arthritis and
arthritis of the hip had the poorest response rate (only 43 percent and
49 percent, respectively). [12]