This work describes the preparation, characterization and functionalization with magnetic nanoparticles of a bone tissue-mimetic scaffold composed of collagen and hydroxyapatite obtained through a biomineralization process. Bone remodeling takes place over several weeks and the possibility to follow it in vivo in a quick and reliable way is still an outstanding issue. Therefore, this work aims to produce an implantable material that can be followed in vivo during bone regeneration by using the existing non-invasive imaging techniques (MRI). To this aim, suitably designed biocompatible SPIONs were linked to the hybrid scaffold using two different strategies, one involving naked SPIONs (nMNPs) and the other using coated and activated SPIONs (MNPs) exposing carboxylic acid functions allowing a covalent attachment between MNPs and collagen molecules. Physico-chemical characterization was carried out to investigate the morphology, crystallinity and stability of the functionalized materials followed by MRI analyses and evaluation of a radiotracer uptake ([^99mTc]Tc-MDP). Cell proliferation assays in vitro were carried out to check the cytotoxicity and demonstrated no side effects due to the SPIONs. The achieved results demonstrated that the naked and coated SPIONs are more homogeneously distributed in the scaffold when incorporated during the synthesis process. This work demonstrated a suitable approach to develop a biomaterial for bone regeneration that allows the monitoring of the healing progress even for long-term follow-up studies.

This study aimed to compare incisional wound healing in cats and dogs after the topical application of Μanuka honey and a new medical device, Dermapliq. Comparisons were made between each treatment and control, between the two treatments, and between dogs and cats. Twelve cats and twelve dogs were included in this study, and the impact of the two substances was examined through cosmetic, clinical, ultrasonographical, and histological evaluation. The use of Dermapliq in first-intention wound healing achieved a significantly better cosmetic evaluation score and better total clinical score at days 20–41, compared to the control, in both dogs and cats. The ultrasonographically estimated wound area was smaller with Dermapliq compared to the control. Wounds treated with Dermapliq showed histologically less inflammation compared to the control. The use of Manuka honey did not show a significantly better cosmetic score compared to the control. Skin thickening was significantly higher after using Manuka honey compared to the control and so was the total clinical score. However, the median wound area, as was evaluated ultrasonographically, was significantly smaller when wounds were treated with Manuka honey, the difference being more apparent in dogs. Dermapliq was proven to be a better choice in achieving favorable wound healing than Manuka honey in dogs and cats in first-intention healing. In our study, cats had a statistically better cosmetic score and less skin thickening and scar width compared to dogs. Histologically, cats showed significantly less edema, higher inflammation and angiogenesis scores, and lower fibroblast and epidermis thickening scores when compared to dogs.

Dermisiadou E, et al. J Vet Sci. 2023 Jan;24:e14. https://doi.org/10.4142/jvs.22158

The objective of this experimental study was to compare the semitendinosus (ST) to the split-semitendinosus (SST) myocutaneous flap in covering distal limb skin defects in cats. Twenty-eight purpose-bred laboratory DSH cats were used and allocated into two groups (ST-group (A); n = 14, SST-group (B); n = 14). ST flaps, based on the distal muscle pedicle, and SST flaps, after longitudinal division of the muscle based on both muscle pedicles, were tested over skin defects created on the medial distal tibia. Clinical assessment, planimetry, CT-angiography (CTA) and histological examination were compared between groups. Days to complete flap healing between ST and SST-flaps (30.36 ± 9.1, 32.29 ± 5.44, respectively) and final total flap areas (68.36% ± 27.18, 51.83% ± 22.48, respectively) revealed no significant differences. On CTAs, the caliber of the distal caudal femoral vein on day 10 was statistically significant higher (p < 0.001) for group A and a significantly higher caliber of the distal caudal femoral artery on day 30 for group B (p = 0.021). Histology revealed statistically higher degeneration at 6 months (p = 0.047) for group A, and statistically higher fibrosis at 12 months (p = 0.019) for group B. Both ST and SST flaps had similar healing times and provided coverage of skin tibial defects in cats.

Management of complex feline hindlimb defects is challenging. However, the use of a split semitendinosus myocutaneous (SST) flap for coverage has not yet been reported. The objective of this study was to describe the SST flap and compare it with second-intention healing for the management of complex tibial defects in cats. Two wounds were created on each tibia of 12 purpose-bred laboratory DSH cats. Wounds in group A (n=12) were covered with SST flaps and those in group B (n=12) were left to heal by second intention. In both groups, clinical assessment scoring and planimetry were performed between 1 and 30 postoperative days. CT angiography (CTA) and histological examination were performed on days 0, 10, and 30 and on days 0, 14, 6, and 12 months postoperatively, respectively. Group A had significantly higher assessment scores on days 7 (p=0.002), 14 (p<0.001), 21 (p=0.001), and 30 (p=0.008). The time to complete healing in group A (32,42 days) was significantly higher than that to complete epithelial coverage in group B (24.67 days) (p=0.001). On CTA, significant differences were observed in ST muscle density which was higher on day 10 compared to 0 on the proximal (dP) (p<0.001) and medial (dM) points (p=0,020, p<0,001, p<0,001 respectively) in all three different phases. For the distal (dD) point, the measurement was significantly higher in the precontrast phase (p=0.001) and on day 10 compared today 30 atn all points in all three phases (p<0.001). The caliber of the distal caudal femoral artery and vein and of the proximal gluteal artery and vein were significantly higher on day 10 than on day 0 (p<0.001), on days 10 to 30 (p<0.001), and on days 30 to 0 (p=0.004, p=0.006, p=0.011, p=0.007, respectively). Histologically significant differences were observed on inflammation and muscle cell degeneration which were higher on day 14 than on day 0 and 6 months (p<0.001, p<0.001, p<0.001, p=0.007 respectively). Neovascularization and fibrosis were significantly higher on day 14 than on day 0 (p=0.010 and p=0.009, respectively). In conclusion, although the ST muscle can be safely longitudinally split and cover tibial defects, the SST flap is less efficient than second-intention healing in terms of the time to complete wound healing.

Skin wounds in dogs and cats are frequently managed by second-intention healing, yet comparative evidence on topical treatments in these species remains limited. This study investigated wound-healing dynamics in dogs and cats using a standardized experimental model that enabled direct interspecies and within-animal comparison of treatment responses during secondary-intention healing. Standardized full-thickness cutaneous wounds were created on the dorsolateral trunk, with multiple wounds per animal randomly assigned to different treatments, including Manuka honey, Dermapliq, and untreated controls. Healing was evaluated using a multimodal approach, including clinical endpoints, planimetric analysis of epithelialization, contraction and total healing, ultrasonographic assessment, and blinded histopathology. Planimetry-derived total wound healing, the primary endpoint, did not differ significantly among treatments, while treatment-associated differences were identified in selected secondary endpoints. Dermapliq-treated wounds reached complete epithelial coverage earlier and showed smaller ultrasonographic wound areas than untreated controls, whereas Manuka honey was associated with faster complete granulation coverage but greater exudate quantity. Interspecies differences were also identified, with cats generally exhibiting slower progression to key healing endpoints than dogs under identical experimental conditions. These findings suggest species-specific healing responses and phase-dependent treatment-associated differences during secondary-intention wound healing in a controlled experimental model. However, they should not be interpreted as evidence of broad treatment superiority. Further studies in naturally occurring, larger, contaminated, infected, or chronic wounds are required before direct clinical extrapolation.