Findings in a study recently published in Nature Medicine showed how high concentrations of transforming growth factor–beta (TGF-β) in the subchondral bone induces the formation of mesenchymal stem cell clusters, and ultimately leads to bone abnormalities.8 This was found in an animal model, but high concentrations of TGF-β also exist in people with osteoarthritis.
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The findings raise the question of the value of a therapy blocking TGF-β, but it is a complicated topic, Dr. Kloppenburg said. “That is not such an easy question to answer because TGF-β also has positive effects,” she said. “So we don’t know that at the moment.”
Another recent study suggests a link between a change in systemic bone mineral density and OA progression. But, she said, researchers have to get at the underlying mechanism and, “that is not easily understood.”
On the role of physical therapy for knee OA, Dr. Kloppenburg pointed to a meta-analysis of more than 80 randomized controlled trials on pain, disability, and physical function.9
Researchers concluded that there is low-strength evidence that several physical therapy interventions are effective. They found aerobic, aquatic, strengthening, and proprioception exercise, as well as ultrasonography, to be effective. But, they found no benefit to diathermy, orthotics, and magnetic stimulation.
Another study, involving 351 patients with mild to moderate knee OA called into question the role of arthroscopic partial meniscectomy in knee OA with pain thought to have arisen from a meniscal tear, finding no significant benefit compared to physical therapy alone.10 However, a proportion of patients assigned to the physical therapy group did cross over to surgery.
The findings, she said, suggest that, “in this patient group, physical therapy is a good option.”
In another study, a randomized controlled trial of 146 symptomatic knee OA patients, there was no benefit found from vitamin D supplementation on pain and structural findings.11
“Although there were substantial ideas from observation studies that vitamin D could be a target to work,” Dr. Kloppenburg said, “it does not come in this randomized controlled trial.”
Thomas Collins is a freelance medical writer based in Florida.
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- Mease P, Fleischmann RM, Wollenhaupt J, et al. Effect of certolizumab pegol on signs and symptoms in patients with psoriatic arthritis with and without prior anti-TNF exposure: 24 week results of a phase 3 double-blind randomized placebo-controlled study. Arthritis Rheum. 2012;64 (Suppl.):S1107.
- Jimenez-Boj E, Stamm TA, Sadlonova M, et al Rituximab in psoriatic arthritis: An exploratory evaluation. Ann Rheum Dis. 2012;71:1868-1871.
- Patel DD, Lee DM, Kolbinger F, Antoni C. Effect of IL-17A blockade with secukinumab in autoimmune diseases. Ann Rheum Dis. 2013;72(Suppl 2):ii116-ii123.
- McInnes IB, Kavanaugh A, Gottlieb AB, et al. Efficacy and safety of ustekinumab in patients with active psoriatic arthritis: 1 year results of the phase 3, multicentre, double-blind, placebo-controlled PSUMMIT 1 trial. Lancet. 2013. pii: S0140-6736;60594-60592.
- Zhen G, Wen C, Jia X, et al. Inhibition of TGF-β signaling in mesenchymal stem cells of subchondral bone attenuates osteoarthritis. Nat Med. 2013;19:704-712.
- Wang SY, Olson-Kellogg B, Shamliyan TA, et al. Physical therapy interventions for knee pain secondary to osteoarthritis: A systematic review. Ann Intern Med. 2012;157:632-644.
- Katz JN, Brophy RH, Chaisson CE, et al. Surgery versus physical therapy for a meniscal tear and osteoarthritis. N Engl J Med. 2013;368:1675-1684.
- McAlindon T, LaValley M, Schneider E, et al. Effect of vitamin D supplementation on progression of knee pain and cartilage volume loss in patients with symptomatic osteoarthritis: A randomized controlled trial. JAMA. 2013;309:155-162.