Purpose
To evaluate the surgical technique, clinical performance, and biocompatibility of a novel keratoprosthesis (KPro) named KPro of Brazil (KoBra) in an alkali-burned rabbit model.
Methods
Two-piece three-dimensional-printed titanium powder and polymethyl methacrylate KPros were implanted into 14 alkali-burned corneas of 14 rabbits using an autologous full-thickness corneal graft as the KPro carrier. Rabbits were examined weekly for 12 months to evaluate retention and postoperative complications. Anterior segment optical coherence tomography (AS-OCT) and scanning electron microscopy (SEM) were performed at the end of the experiment to evaluate the relationship between the KoBra and the carrier graft.
Results
All surgeries were performed without intraoperative complications, and the immediate postoperative period was uneventful. In 12 eyes (85.7%), the implanted KPros integrated into the operated eyes and maintained clear optics without extrusion or further complications over 12 months. Two eyes presented late postoperative complications that progressed to KPro extrusion: one had a presumed infectious keratitis, and the other had sterile stromal necrosis. AS-OCT demonstrated the correct relationship of the device and carrier graft in all remaining animals at the final follow-up. SEM findings indicate the integration of the porous structure of the back plate into the surrounding tissue.
Conclusions
Clinical evaluations, AS-OCT, and SEM findings indicate good biointegr-ation of the implanted device into the corneal carrier graft. KoBra has the advantage of using recipients’ own corneas as the prosthesis supporter, and its surgical procedure is relatively simple and safe.
Translational Relevance
Titanium three-dimensional-printed technology used in an animal limbal stem-cell deficiency model holds great promise for the treatment of corneal blindness in humans.
There are few published data on the relationship between loss of bone mass due to osteoporosis and poor tooth quality. This study analyzed the effects of osteoporosis on incisor teeth and femoral bones using optical techniques in rats. Twenty female Wistar rats aged 6 months (n = 20) were randomized into two groups: control group, non-ovariectomized rats (n = 10); ovariectomy group, ovariectomized rats to induce osteoporosis (n = 10). Each group was subdivided randomly into two groups containing five rats each as follows. Control group 1: non-ovariectomized rats euthanized at the age of 9 or 3 months post-ovariectomy (n = 5); Control group 2: non-ovariectomized rats euthanized at the age of 1 year or 6 months post-ovariectomy (n = 5); ovariectomy group 1: ovariectomized rats euthanized at the age of 9 months or 3 months post-ovariectomy (n = 5); ovariectomy group 2: ovariectomized rats euthanized at the age of 1 year or 6 months post-ovariectomy (n = 5). The incisor teeth and femoral bones of Wistar rats were removed to perform Raman spectroscopy using an excitation laser at 785 nm. In addition, an energy-dispersive X-ray spectrometer system was used to evaluate calcium (Ca) and phosphorus (P). The main findings included significant changes (p < 0.05) for phosphate and carbonate band areas for both incisor teeth and femur bones. In addition, there was significant negative correlation between the P concentration and phosphate/carbonate ratio (lower P content-larger ratio, p < 0.05) for incisor teeth and femoral bones. The proline and CH wag band areas were significantly reduced only for the incisor teeth (p < 0.05). Therefore, Raman spectroscopy assessed the compositional, physicochemical and structural changes in hard tissue. The current study also pointed out the possible action mechanisms of these changes, bone fracture risk and dental fragility. It is important to emphasize that poor dental quality may also occur due to osteoporosis.
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