Widely used by doctors to soften forehead wrinkles and reduce uncontrollably sweaty armpits, researchers are exploring botulinum toxin as a potential therapy forosteoarthritis (OA) pain.
“TheBotoxstory is very intriguing,” says David Felson, MD, MPH, professor of medicine and epidemiology at Boston University School of Medicine. “It isn’t just muscles. It can paralyze nerves. Just like celebrities injecting it into wrinkles, it could have the same effect on a hip muscle.Botox会麻痹传递疼痛的肌肉
This toxin may eventually be used to treat OA patients whose pain is not sufficiently controlled by traditional medicines like NSAIDs or analgesics, and for patients who may experience adverse effects from those medicines, says Dr. Felson.
One of the more recent studies was reported at the 2013 European League Against Rheumatism (EULAR) conference. In the study, 45 patients were injected with either hyaluronic acid (HA) alone or a combination of HA plus Botox and monitored at one, three, and six months. After one month, the Botox group showed a significant decrease in WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) pain and physical function scores that sustained through six months.
Blocks Pain Signals
In the same action that botulinum toxin flattens wrinkles for up to six months, the substance “blocks the neuromuscular junction, so the nerve can’t transmit signals to the muscle and it prevents contraction,” says Eric Hsu, MD, a pain specialist at Ronald Reagan-UCLA Medical Center in Los Angeles.
Although the studies conducted so far are small and look at short-term results, the results of these recent studies are “impressive,” says Dr. Felson.
He points to a Minneapolis-based study published in theJournal of Rheumatology在2010年研究了54名在全膝关节置换术后经历慢性疼痛的患者。一些被注射了肉毒杆菌毒素A，一些被注射了安慰剂。结果是显著的:与接受安慰剂注射的35%相比，注射肉毒杆菌毒素的人中有71%的人实现了临床意义上的疼痛减轻和关节可测量的身体功能改善。
Another study published in the PMR, the Journal of Injury, Function and Rehabilitation in 2010 looked at 60 patients aged 40 years or older with painful osteoarthritis of the knee who had failed physical therapy, medications and/or injection therapy. After an 8-week treatment of botulinum toxin A, they showed statistically significant improvements in WOMAC scores for pain, stiffness and function that lasted for six months.
An Italian study published in theJournal of Rehabilitative Medicine在2010年观察了A型肉毒毒素注射对髋关节骨性关节炎患者大腿肌肉疼痛的效果。所有患者在注射后2周、4周和12周髋关节功能和疼痛均有改善。
炎症可能的治疗方法?
另一项研究表明，肉毒杆菌毒素有朝一日也可能被用于治疗炎症，从而引起了人们的进一步兴趣。Published in the journalBiochemistryin 2011, it explored a future use of botulinum toxin: Treating chronic inflammation, not just temporarily relieving pain. Felix Yeh, PhD, who led the study and is now working in the private sector in San Francisco, said the focus of the study was to learn how toxins get into neurons, something he calls “a Trojan horse strategy.”
Yeh和他的同事们利用B型肉毒毒素(一种市场上相对较新的产品)在实验室小鼠身上证明，这种神经毒素可以被重新定向，以抑制肿瘤坏死因子α的释放，这是一种关键的细胞因子，是类风湿性关节炎等自身免疫性疾病炎症的可能原因之一。
Physicians Urge Caution
Physicians treating patients with serious chronic joint pain see botulinum toxin as potentially useful, but urge caution at this point. Although studies haven’t shown serious adverse effects, Dr. Felson speculates that injecting it into large muscles supporting weight-bearing joints, such as the thigh, might impair one’s ability to walk, for example.
到目前为止，结果看起来很有希望，所以许博士抱有希望。“我认为，像这样的事情，不会像其他治疗方法那样引起全身、多器官的副作用，是我们帮助患者的一个潜在选择。”
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