Diacerein Versus Chondroitin Sulfate in Treatment of Adult Kashin-Beck Disease: An Intervention Trial in Heilongjiang Province, China

Background: Kashin-Beck disease (KBD) is a special type of osteoarthritis and has disabled and stunted the growth of hundreds of people in China. It also can affect patients' ability to work and live. So, how to conduct effective treatment for adult KBD patients has become a major public health problem in current KBD endemic areas. In this trial, therapeutic effects of diacerein and chondroitin sulfate on adult KBD was to evaluate and compare so that we can screen out more suitable drug. Methods: 308 KBD patients were divided into two groups and received chondroitin sulphate (Group A) and diacerein (Group B) for 24 weeks, respectively. Data were collected at 0 week (baseline), 12 weeks (primary end point) and 24 weeks (secondary end point) to calculate the proportion of patients with effective therapeutic effect and overall improvement rate (primary efficacy parameters), WOMAC pain and stiffness scores (secondary efficacy parameters). Blood sample was collected to measure liver and renal function indexes. All indexes and parameters were analysed with SPSS software and intent-to-treat (ITT) analysis was applied. Results: Two primary efficacy parameters in group B at primary end point were significantly higher than those in group A (P=0.021, P=0.007), but no statistical differences were seen in these two primary efficacy parameters between two groups at secondary end point or between primary and secondary end points in same group (all P>0.05). In both groups, with the prolongation of treatment time, WOMAC pain and stiffness scores decreased significantly (all P<0.001), but no significant differences were seen between primary and secondary end points (all P>0.05). In addition, in both groups, the occurrences of total adverse events were relatively low and no side effect on liver function was seen. Diacerein also had no side effect on renal function. Conclusion: For treatment of adult KBD, both diacerein and chondroitin sulfate were effective, and diacerein might work stronger than chondroitin sulfate. Taking into account both efficacy and safety, the optimal intervention time of diacerein was 12 weeks. Trial registration: The trial was registered complementally on 31/10/2020, and the registration number in the Chinese Clinical Trial Registry is ChiCTR2000039600 (http://www.chictr.org.cn).

In-Depth Molecular Dynamics Study of All Possible Chondroitin Sulfate Disaccharides Reveals Key Insight into Structural Heterogeneity and Dynamism

GAGs exhibit a high level of conformational and configurational diversity, which remains untapped in terms of the recognition and modulation of proteins. Although GAGs are suggested to bind to more than 800 biologically important proteins, very few therapeutics have been designed or discovered so far. A key challenge is the inability to identify, understand and predict distinct topologies accessed by GAGs, which may help design novel protein-binding GAG sequences. Recent studies on chondroitin sulfate (CS), a key member of the GAG family, pinpointing its role in multiple biological functions led us to study the conformational dynamism of CS building blocks using molecular dynamics (MD). In the present study, we used the all-atom GLYCAM06 force field for the first time to explore the conformational space of all possible CS building blocks. Each of the 16 disaccharides was solvated in a TIP3P water box with an appropriate number of counter ions followed by equilibration and a production run. We analyzed the MD trajectories for torsional space, inter- and intra-molecular H-bonding, bridging water, conformational spread and energy landscapes. An in-house phi and psi probability density analysis showed that 1→3-linked sequences were more flexible than 1→4-linked sequences. More specifically, phi and psi regions for 1→4-linked sequences were held within a narrower range because of intra-molecular H-bonding between the GalNAc O5 atom and GlcA O3 atom, irrespective of sulfation pattern. In contrast, no such intra-molecular interaction arose for 1→3-linked sequences. Further, the stability of 1→4-linked sequences also arose from inter-molecular interactions involving bridged water molecules. The energy landscape for both classes of CS disaccharides demonstrated increased ruggedness as the level of sulfation increased. The results show that CS building blocks present distinct conformational dynamism that offers the high possibility of unique electrostatic surfaces for protein recognition. The fundamental results presented here will support the development of algorithms that help to design longer CS chains for protein recognition.

A Semi-Quantitative Assay to Measure Glycosaminoglycan Degradation by the Urinary Microbiota

Glycosaminoglycans (GAGs) are linear polysaccharides and are among the primary components of mucosal surfaces in mammalian systems. The GAG layer lining the mucosal surface of the urinary tract is thought to play a critical role in urinary tract homeostasis and provide a barrier against urinary tract infection (UTI). This key component of the host-microbe interface may serve as a scaffolding site or a nutrient source for the urinary microbiota or invading pathogens, but its exact role in UTI pathogenesis is unclear. Although members of the gut microbiota have been shown to degrade GAGs, the utilization and degradation of GAGs by the urinary microbiota or uropathogens had not been investigated. In this study, we developed an in vitro plate-based assay to measure GAG degradation and utilization and used this assay to screen a library of 37 urinary bacterial isolates representing both urinary microbiota and uropathogenic species. This novel assay is more rapid, inexpensive, and quantitative compared to previously developed assays, and can measure three of the major classes of human GAGs. Our findings demonstrate that this assay captures the well-characterized ability of Streptococcus agalactiae to degrade hyaluronic acid and partially degrade chondroitin sulfate. Additionally, we present the first known report of chondroitin sulfate degradation by Proteus mirabilis, an important uropathogen and a causative agent of acute, recurrent, and catheter-associated urinary tract infections (CAUTI). In contrast, we observed that uropathogenic Escherichia coli (UPEC) and members of the urinary microbiota, including lactobacilli, were unable to degrade GAGs.