Scientists have known since the 1800s what happens to a totally crushed peripheral nerve in animals: the damaged axons are broken down in a process called Wallerian degeneration, allowing healthy ones to regrow. But humans rarely suffer complete axonal damage. Instead, axons tend to be partially damaged, causing neuropathic pain — a difficult-to-treat, chronic pain associated with nerve trauma, chemotherapy and diabetes.
Neuropathic pain is chronic pain originating through some malfunction of the nervous system, often triggered by an injury. It causes hypersensitivity to innocuous stimuli and is often extremely debilitating. It doesn’t respond to existing painkillers — even opioids can’t reach it well.
New research in a mouse model, described last week in Cell Reports, deconstructed neuropathic pain and could offer new leads for treating it. The carefully done study showed that two major neuropathic pain symptoms in patients — extreme touch sensitivity and extreme cold sensitivity — operate through separate pathways.
“We think this separation will allow targeted drug-based therapies in the future,” says Michael Costigan, PhD, of the F.M. Kirby Neurobiology Center at Boston Children’s Hospital, who was the study’s senior investigator. “If our results stand experimental scrutiny by others, this will be profoundly important in our overall understanding of neuropathic pain.” …
As the opioid epidemic deepens and drug overdoses increase, effective non-addicting painkillers are desperately needed. Efforts to discover new pain pathways to target with new drugs have thus far had little success. Other promising research is investigating triggerable local delivery systems for non-opioid nerve blockers, but it’s still in the early stages.
A new collaboration between Boston Children’s Hospital and the biopharmaceutical company Amgen is aimed at accelerating new pain treatments. Announced yesterday, it will revolve around patients with rare, perplexing pain syndromes. The scientists hope that the genetic variants they find in these patients will shed new light on pain biology and lead to new ways of controlling pain.…
Second in a two-part series on nerve regeneration. Read part 1.
The search for therapies to spur regeneration after spinal cord injury, stroke and other central nervous system injuries hasn’t been all that successful to date. Getting nerve fibers (axons) to regenerate in mammals, typically lab mice, has often involved manipulating oncogenes or tumor suppressor genes to encourage growth, a move that could greatly increase a person’s risk of cancer.