Investigating the Association of Metabolic Biomarkers With Knee Cartilage Composition and Structural Abnormalities Using MRI: A Pilot Study

The effect of pentosan polysulfate sodium for improving dyslipidaemia and knee pain in people with knee osteoarthritis: A pilot study

Objective

To evaluate the efficacy and safety of pentosan polysulfate sodium (PPS, Elmiron®) for dyslipidaemia and knee osteoarthritis (OA) related symptoms.

Method

This was a single-arm, open-label, prospective, non-randomised pilot study. People with painful knee OA and a history of primary hypercholesterolemia were included. PPS was taken orally in a dosage of 10 ​mg/kg once every 4 days for 5 weeks for two cycles. There was 5 weeks of no medication between the cycles. The main outcomes included the change in lipidemia levels, the change in knee OA-related symptoms assessed by pain numerical rating scale (NRS) and Knee Osteoarthritis Outcome Score (KOOS), and knee MRI semi-quantitative score. The changes were analysed using paired t-tests.

Results

38 participants were included, with a mean age of 62.2 years. We found a statistically significant decrease in total cholesterol (from 6.23 ​± ​0.74 to 5.95 ​± ​0.77 ​mmol/L; P ​= ​0.01) and low-density lipoprotein (from 4.03 ​± ​0.61 to 3.82 ​± ​0.61 ​mmol/L; P ​= ​0.009) from baseline to week 16. Knee pain NRS was significantly reduced at weeks 6, 16 and 26 from 6.39 ​± ​1.33 to 4.18 ​± ​1.99, 3.63 ​± ​2.28 and 4.38 ​± ​2.55, respectively (P ​< ​0.001). However, there was no significant difference in terms of the primary outcome of triglyceride levels before and after treatment. The most common AEs were positive faecal occult blood tests, followed by headache and diarrhoea.

Conclusion

The findings suggest that PPS has promising effects on improving dyslipidaemia and symptomatic pain relief in people with knee OA.

Biomarkers of Osteoarthritis—A Narrative Review on Causal Links with Metabolic Syndrome

Development of OA (OA) is multifactorial and is strongly associated with risk factors such as aging, trauma, metabolic disorders, and obesity. Metabolic Syndrome (MetS)-associated OA, collectively coined MetS-OA, is an increasingly recognized entity in which metabolic disorders and low-grade inflammation play a key mechanistic role in the disruption of joint homeostasis and cartilage degradation. Although there have been enormous efforts to discover biomarkers of MetS and OA, studies investigating a pathophysiological link between MetS and OA are relatively limited, and no serum blood marker has proved diagnostic so far. OA biomarkers that are necessary to discriminate and diagnose early disease remain to be elicited, explained in part by limited prospective studies, and therefore limited tools available to utilize in any prognostic capacity. Biomarker validation projects have been established by the Biomarker Consortium to determine biochemical markers demonstrating predictive validity for knee OA. Given that the metabolic constituents of MetS are treatable to varying extents, it stands to reason that treating these, and monitoring such treatment, may help to mitigate deleterious links with OA development. This narrative review will describe the current state of biomarker identification and utility in OA associated with MetS. We discuss the pathophysiological mechanisms of disease according to constituent pathologies of MetS and how identification of biomarkers may guide future investigation of novel targets.

Tissue Engineering of Canine Cartilage from Surgically Debrided Osteochondritis Dissecans Fragments

This study in dogs explored the feasibility of using cartilage fragments removed and discarded during routine palliative surgery for osteochondritis dissecans (OCD) as a source of primary chondrocytes for scaffold-free cartilage tissue-engineering. Primary chondrocytes were obtained from three OCD donors and one age-matched healthy articular cartilage (HAC) donor. After monolayer expansion of primary cells, a three-dimensional spherical suspension culture was implemented. Following this stage, cells were seeded at a high density into custom-made agarose molds that allowed for size and shape-specific constructs to be generated via a method of cellular self-assembling in a scaffold-free environment. Fifty-eight neocartilage constructs were tissue-engineered using this methodology. Neocartilage constructs and native cartilage from shoulder joint were subjected to histological, mechanical, and biochemical testing. OCD and HAC chondrocytes-sourced constructs had uniformly flat morphology and histology consistent with cartilage tissue. Constructs sourced from OCD chondrocytes were 1.5-times (32%) stiffer in compression and 1.3 times (23%) stronger in tension than constructs sourced from HAC chondrocytes and only 8.7-times (81%) less stiff in tension than native tissue. Constructs from both cell sources consistently had lower collagen content than native tissue (22.9%/dry weight [DW] for OCD and 4.1%/DW for HAC vs. 51.1%/DW native tissue). To improve the collagen content and mechanical properties of neocartilage, biological and mechanical stimuli, and thyroid hormone (tri-iodothyronine) were applied to the chondrocytes during the self-assembling stage in two separate studies. A 2.6-fold (62%) increase in compressive stiffness was detected with supplementation of biological stimuli alone and 5-fold (81%) increase with combined biological and mechanical stimuli at 20% strain. Application of thyroid hormone improved collagen content (1.7-times, 33%), tensile strength (1.8-times, 43%), and stiffness (1.3-times, 21%) of constructs, relative to untreated controls. Collectively, these data suggest that OCD chondrocytes can serve as a reliable cell source for cartilage tissue-engineering and that canine chondrocytes respond favorably to biological and mechanical stimuli that have been shown effective in chondrocytes from other animal species, including humans.