Men who stare at bone: multimodal monitoring of bone healing

Radiological properties of nano-hydroxyapatite compared to natural equine hydroxyapatite quantified using dual-energy CT and high-field MR

In equine medicine, assisted bone regeneration, including use of biomaterial substitutes like hydroxyapatite (HAP), is crucial for addressing bone defects. To follow-up on the outcome of HAP-based bone defect treatment, the advancement in quantified diagnostic imaging protocols is needed. This study aimed to quantify and compare the radiological properties of the HAP graft and natural equine bone using Magnetic Resonance (MR) and Computed Tomography (CT), both Single (SECT) and Dual Energy (DECT). SECT and DECT, allow for the differentiation of three HAP grain sizes, by progressive increase in relative density (RD). SECT, DECT, and MR enable the differentiation between natural cortical bone and synthetic HAP graft by augmentation in Effective Z and material density (MD) in HAP/Water, Calcium/Water, and Water/Calcium reconstructions, alongside the reduction in T2 relaxation time. The proposed quantification provided valuable radiological insights into the composition of HAP grafts, which may be useful in follow-up bone defect treatment.

Microdialysis Reveals Anti-Inflammatory Effects of Sulfated Glycosaminoglycanes in the Early Phase of Bone Healing

Although chronic inflammation inhibits bone healing, the healing process is initiated by an inflammatory phase. In a well-tuned sequence of molecular events, pro-inflammatory cytokines are secreted to orchestrate the inflammation response to injury and the recruitment of progenitor cells. These events in turn activate the secretion of anti-inflammatory signaling molecules and attract cells and mediators that antagonize the inflammation and initiate the repair phase. Sulfated glycosaminoglycanes (sGAG) are known to interact with cytokines, chemokines and growth factors and, thus, alter the availability, duration and impact of those mediators on the local molecular level. sGAG-coated polycaprolactone-co-lactide (PCL) scaffolds were inserted into critical-size femur defects in adult male Wistar rats. The femur was stabilized with a plate, and the defect was filled with either sGAG-containing PCL scaffolds or autologous bone (positive control). Wound fluid samples obtained by microdialysis were characterized regarding alterations of cytokine concentrations over the first 24 h after surgery. The analyses revealed the inhibition of the pro-inflammatory cytokines IL-1β and MIP-2 in the sGAG-treated groups compared to the positive control. A simultaneous increase of IL-6 and TNF-α indicated advanced regenerative capacity of sGAG, suggesting their potential to improve bone healing.

L-Se-methylselenocysteine loaded mucoadhesive thermogel for effective treatment of Vulvar candidiasis

Vulvar candidiasis (VVC) is a vaginitis caused by vaginal mucosa infection of Candida, which greatly impairs women's health. Although there are more and more thiazoles on the market, new classes of antifungal drugs are still missing, it is still challenging to treat azole-resistant candidal vaginitis. We found that L-Se-methylselenocysteine (L-SeMC) could effectively inhibit the growth of Candida albicans, reduce the density and length of the mycelia. To extend the retention time of L-SeMC in the vaginal tract and enhance its therapeutic effect for VVC, a mucoadhesive thermogel (NAC-HA thermogel) was successfully synthesized and prepared. The gelation window was around 29-56℃ for L-SeMC loaded mucoadhesive thermogel (L-SeMC@NAC-HA thermogel), which exhibited a sustained release profile in the in vitro release study and an extended retention time in the vaginal tract. Besides, L-SeMC@NAC-HA thermogel exhibited a good safety profile in the in vivo safety study. The in vivo anti-VVC effect was examined in a rat VVC model and L-SeMC@NAC-HA thermogel significantly reduced the number of Candida albicans in the vaginal secreta, mitigated the vaginal damage and reduced the secretion of proinflammatory factors (TNF-α, IL-1α and IL-β). Therefore, it is a promising therapy for the clinical treatment of VVC in the near future.