Is This Old Therapy Worth Its Weight in Gold?
Prized for its luster, purity, and value, gold may be the first metal used by humans. In its raw form, it appears more like a dark yellow rock. The first known health-related use of gold was recorded by the ancient Egyptians approximately 4500 years ago.1 Gold dental work has been found in archeologic sites, indicating that the Egyptians mined, extracted, and shaped the mineral for a wide variety of uses in their civilization. Modern use of gold in medicine began in the early 1900s and was referred to as aurotherapy or chrysotherapy.2
Gold is classified as a metal, with the elemental designation of Au. It has a density of nearly 20 g/cm3 and does not melt until it reaches an amazing 1948 degrees Fahrenheit.3 Because of its purity, gold is an inert element when used in the human body. This biocompatibility has made it extremely useful in many areas of dentistry and medicine. Anti-inflammatory and antimicrobial actions have since been widely recognized.
The anti-inflammatory mechanism of gold compounds is still one of speculation, but mounting evidence indicates that gold is taken into intracellular organelles and stored in lysosomes. There, it both inhibits the processing of antigenic agents and blocks the reactive processes that produce and release inflammatory cytokines.4,5 Research that was originally directed at the use of gold in rheumatoid arthritis evolved to show potential uses in antimicrobial therapy as well as antiviral therapy. Ongoing studies exploring the use of gold in the treatment of conditions such as cancer and human immunodeficiency virus show promising potential.
Even though the use of gold products to treat rheumatoid arthritis has declined since the development of newer anti-inflammatory agents and biologic disease-modifying antirheumatic drugs (DMARDs), its efficacy still appeals to many. In a systematic review of the gold drug auranofin versus placebo for the treatment of rheumatoid arthritis, the gold compound was more efficacious when patient outcomes were scored on the presence of tender joints, pain, and erythrocyte sedimentation rate.6
In a 48-week randomized, placebo-controlled trial, researchers examined the results of using both oral methotrexate and intramuscular gold therapy in patients with rheumatoid arthritis whose disease was not sufficiently controlled on methotrexate alone. The researchers reported significant clinical improvement after adding intramuscular gold therapy to methotrexate.7
The same mechanisms of action are being explored for possible anticancer and antimicrobial actions. Gold microparticles in a cancer cell appear to accelerate cell death as well as upregulate tumor-suppressing signals.8 Gold has also been shown to both inhibit cell growth of certain infectious microbes and make these cells more susceptible to oxidative stress and death.9 Laboratory researchers have demonstrated that relatively low intracellular concentrations of gold microparticles exhibit definite inhibitory action against cultures of methicillin-resistant Staphylococcus aureus.10