Okayama University researchers identify clodronate for chronic pain treatment

Researchers at Japan’s Okayama University have demonstrated the effect of clodronate on the regulation of adenosine triphosphate (ATP) release and its potential as a drug for the treatment of chronic pain.

While typical drugs used for treating chronic pain are often accompanied by serious side effects, such as stomach problems, kidney failure or addiction, clodronate inhibits the mechanism triggering chronic pain while having only a few side effects.

Identified by a team of researchers led by Yuri Kato and Takaaki Miyaji from Okayama University, clodronate might also be used to treat other medical conditions including diabetes and neurological disorders.

Pain that lasts for a long time, typically three months or more, is called chronic pain, as opposed to acute pain.

Chronic pain can be neuropathic, when the nervous system is damaged, or nociceptive, when inflammation causes nociceptors (pain sensors) to be triggered permanently.

Inflammation or nerve injuries can cause pathological nociception, which is a long-lasting sensation of pain due to the stimulated production of ATP molecules that bind to purinergic receptors, causing pain responses.

The ATP molecules participating in the purinergic signalling processes are carried by vesicular nucleotide transporter (VNUT) protein.

As revealed in the study, clodronate inhibits VNUT, which in turn attenuates neuropathic and nociceptive pain.

The researchers tested clodronate, a molecule belonging to the class of bisphosphonates, which are compounds used for treating osteoporosis.

Clodronate does not contain nitrogen, which is claimed to decrease therapeutic effect for osteoporosis and the number of side effects. Its therapeutic effectiveness is also stronger than that of other widespread treatments for neuropathic pain.