Stem cell bandages – an investigation into the therapeutic effect of adipose-derived mesenchymal stem cells in corneal wound healing

Ph. D. ThesisHuman corneal regenerative capacity is not enough to heal deep injuries that causes scars, such abrasions result in the formation of the irregular extracellular matrix that leads to scar and often results in corneal transparency and vision reduction. Because of the limited number of corneal donors for transplantation, there has been an increased interest in cell therapy. Adipose-derived stem cells (ASCs) showed a promising choice for they are environmentally responsive in wound repair. ASCs can secrete paracrine factors and extracellular molecules that have immunomodulatory, angiogenic, trophic, anti-fibrotic, and antimicrobial activity. This thesis explores the formation of bandages; such bandages are formed of sodium alginate. Alginates are present in nature and extracted from brown seaweed. Generally, this material is safe, cost-effective, and wildly used in biomedical applications due to its biocompatibility and ease of handling. Hypothermic temperatures are also explored in here for bandage storage. Hence, this project hypothesized the formation of hypothermically stored ASCs bandages and their beneficial effect on corneal injuries. ASCs bandages were found to improve in vitro corneal scratch wounds, while storage at 15°C presented a favorable condition to store the bandages to vastly enhance their therapeutic potential. This storage is suggested to be a hypoxia-induced environment that augments cells ability to produce paracrine factors. Thus, hypoxia-induced ASCs bandages showed a promising therapeutic ability in healing corneal injures. Gene assessment and protein array revealed the production of several paracrine factors including HGF, TSG-6, IL-8, MCP1, TSP-1 that aid in wound healing. In vivo, hypoxia-induced ASCs bandages were transferred to adult male mice corneas following a chemical burn, where reduction of immune cell infiltration was observed. Thus, supporting this thesis hypothesis

Early clinical and radiological outcomes of the new porous titanium shell in combination with locking screw in revision total hip arthroplasty

Abstract Introduction Extensive acetabular bone loss and poor bone quality are two key challenges often encountered in revision total hip arthroplasty. A new 3D-printed porous acetabular shell has been made available with the option to insert multiple variable-angle locking screws. We sought to evaluate the early clinical and radiological outcomes of this construct. Methods A retrospective review of patients operated by two surgeons was performed in a single institution. Fifty-nine revision hip arthroplasties were performed in 55 patients (34 female; mean age 68.8 ± 12.3 years) for Paprosky defects I (n = 21), IIA/B (n = 22), IIC (n = 9), III (n = 7) between February 2018 and January 2022 using the novel porous titanium acetabular shell and multiple variable angle locking screws. Postoperative clinical and radiographic outcomes were locally maintained. Patient-reported outcome measures collected included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Oxford Hip Score, and the 12-item Short Form Survey. Results After a mean follow-up of 25.7 ± 13.9 months, two cases of shell migration were noted. One patient had a failed constrained mechanism and received revision to a cemented dual mobility liner. No other acetabular shells showed any evidence of radiographic loosening at the final follow-up. Preoperatively, 21 defects were classified as Paprosky grade I, 19 grade IIA, 3 grade IIB, 9 IIC, 4 grade IIIA, and 3 IIIB. The mean postoperative WOMAC function score was 84 (SD 17), WOMAC (stiffness) 83 (SD 15), WOMAC (pain) 85 (SD 15), and WOMAC (global) 85 (SD 17). The mean postoperative OHS was 83 (SD 15), and mean SF-12 physical score was 44 (SD 11). Conclusion The additional augmentation of porous metal acetabular shells with multiple variable-angle locking screws provides reliable initial fixation with good clinical and radiological outcomes in the short term. Further studies are needed to establish the medium- and long-term outcomes. Level of evidence IV