From EurekAlert!: "Early-stage research [in mice] has found that a new gene therapy can nearly eliminate arthritis pain, and significantly reduce long-term damage to the affected joints ... If all goes well with a follow-up study currently underway, researchers will apply [to] begin human trials next year. ... researchers used gene therapy to increase by about one thousand times the number of opioid receptors expressed on the surfaces of nerve cells that carry pain messages back and forth between an osteoarthritic jaw joint and the spinal cord. ... nerve cells involved in pain transmission [became] drastically more responsive to the naturally occurring painkiller ... [this] work has contributed to the emerging theory that pain is not a symptom of osteoarthritis, but is instead part of the disease. According to this new paradigm, pain is composed of nerve messages that over time cause permanent chemical changes in the pathways they travel along, making them more sensitive to pain and encouraging inflammation. This two-way 'crosstalk' may mean that arthritis in one joint can spread, through the central nervous system (CNS), to other joints. Worse yet, joint arthritis may export inflammation to the brain, where it plays a role in neurological conditions (e.g. Alzheimer's disease, dementia and multiple sclerosis)."