Rheological study of hyaluronic acid derivatives

The viscoelastic properties of four novel, low molecular weight hyaluronic acid derivatives were investigated and compared to the parent hyaluronic acid compound. Briefly, all derivatives were synthesized by first deacetylating the parent hyaluronic acid. One sample was left as such, while two others were reacytelated. The final compound, of particular interest for its anti-inflammatory properties, was butyrylated. The compounds were dissolved in phosphate buffer solution (PBS) and studied at a concentration of 5 mg/mL. Shear thinning behaviour was observed for all compounds, however, derivative samples had a lower viscosity than the parent compound at high shear rates. Viscoelastic properties were also observed to decrease as a result of the derivative preparation method. It is believed that these changes are primarily caused by a decrease in hyaluronic acid molecular weight. By increasing the concentration of the anti-inflammatory compound, it may be possible to modulate the viscoelastic properties to more closely resemble those of commercial viscosupplements. As a result, an anti-inflammatory derivative of hyaluronic acid may potentially improve upon existing viscosupplements used to treat patients who are susceptible to flare up.

Effects of Adjuvant Hydrotherapy on Functional Status and Mental Relaxation in Patients with Knee Osteoarthritis: Preliminary Study

BACKGROUND: The aim of this study is to test if adjuvant hydrotherapy with viscosupplement is beneficial on management of pain, stiffness, function, and mental relaxation in knee osteoarthritis (OA). METHODS: Nineteen patients with OA were randomly assigned to hydrotherapy or control groups. All patients received viscosupplement injections once a week for 3 weeks. Hydrotherapy group (n=9) had a spa containing green tea, 3 days a week for 2 weeks. The control group (n=10) received only injections. All patients were assessed at baseline and after the third injection. All were assessed for pain (visual analog scale, VAS), pain severity, and functional status (Western Ontario and McMaster Universities osteoarthritis index, WOMAC), emotional status, quality of life (Euro quality of life health-related quality of life inventory five dimension, EQ-5D), and relative spectral power of alpha waves in electroencephalography (EEG). RESULTS: Both groups reported a statistically significant reduction of pain at the end of treatment and detailed assessment of pain, and function in WOMAC and the relative power of alpha in electroencephalogram showed statistical significant difference only in the hydrotherapy group. However, there were no significant intergroup differences, except for VAS score. CONCLUSION: Adjuvant 2-week hydrotherapy to viscosupplement might have a modest role in the management of pain and functional disability and the mental relaxation in patients with knee OA. Larger, randomized controlled trials with intervention of long term period to determine efficacy in treating knee OA are warranted.