Corneal transplantation is a typical surgical procedure for severe corneal diseases. However, the waiting time for a donor cornea has gradually increased due to a decrease in supply caused by an aging population and increased cases of laser-based surgeries. Artificial corneas were developed to meet the increase in demand; however, these approaches have suffered from material deterioration resulted by the limited tissue integration. Here, we introduce a cornea-derived decellularized extracellular matrix (Co-dECM) as a bioink for corneal regeneration. The developed Co-dECM bioink had similar quantitative measurement results for collagen and GAGs compared with that of the native cornea and also had the proper transparency for vision. The differentiation potential of human turbinate-derived mesenchymal stem cells (hTMSCs) to a keratocyte lineage was only observed in the Co-dECM group. Moreover, the developed bioink did not have any cytotoxic effect on encapsulated cells for three-dimensional (3D) culture and has great biocompatibility evident by the xeno-implantation of the Co-dECM gel into mice and rabbits for two and one month, respectively. An in vivo safety similar to clinical-grade collagen was seen with the Co-dECM, which helped to maintain the keratocyte-specific characteristics in vivo, compared with collagen. Taken together, the Co-dECM bioink has the potential to be used in various types of corneal diseases based on its corneal-specific ability and design flexibility through 3D cell printing technology.

Haptoglobin, a conserved plasma glycoprotein, forms very stable soluble complexes with free plasma hemoglobin. Hemoglobin binding by haptoglobin is thought to be important in the rapid hepatic clearance of hemoglobin from the plasma and in the inhibition of glomerular filtration of hemoglobin. To evaluate these functions,Haptoglobin knockout (−/−) mice were created. These mice were viable but had a small, significant reduction in postnatal viability. Contrary to popular belief, the lack of haptoglobin did not impair clearance of free plasma hemoglobin in −/− mice. Induction of severe hemolysis by phenylhydrazine caused extensive hemoglobin precipitation in the renal tubular cells of both −/− and +/+ mice, with death occurring in 55% of −/− mice and in 18% of +/+ mice. In general, phenylhydrazine-treated −/− mice suffered greater tissue damage, as evidenced by the induction of hepatic acute phase response resulting in increased plasma alpha 1-acid glycoprotein (AGP) levels. Among −/− and +/+ mice that survived, −/− mice tend to suffer greater oxidative damage and failed to repair or regenerate damaged renal tissues, as indicated by their higher plasma malonaldehyde (MDA) and 4-hydroxy-2(E)-nonenal (HNE) levels and lower mitotic indices in their kidneys, respectively. This study suggested that a physiologically important role of hemoglobin-haptoglobin complex formation is the amelioration of tissue damages by hemoglobin-driven lipid peroxidation. © 1998 by The American Society of Hematology.

The He plasma treatments on PIM zirconia implants made the surface more hydrophilic and enhanced the osseointegration of the implants without changing the micro-topography.

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PLSum5 >24 mm is the suggested criterion for identifying high-risk thin biotype patients based on the comparison with the results from gingival transparency inspection. A clinical reevaluation of this criterion should be examined in additional studies for application in real clinical situations.

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The aim of this study was to compare osseointegration and surface characteristics of zirconia implants made by the powder injection molding (PIM) technique and made by the conventional milling procedure in rabbit tibiae. Surface characteristics of 2 types of implant were evaluated. Sixteeen rabbits received 2 types of external hex implants with similar geometry, machined zirconia implants and PIM zirconia implants, in the tibiae. Removal torque tests and histomorphometric analyses were performed. The roughness of PIM zirconia implants was higher than that of machined zirconia implants. The PIM zirconia implants exhibited significantly higher bone-implant contact and removal torque values than the machined zirconia implants (P < 0.001). The osseointegration of the PIM zirconia implant is promising, and PIM, using the roughened mold etching technique, can produce substantially rough surfaces on zirconia implants.

Background: Nerve injuries with a gap/defect represent a clinical challenge without a clear solution. Reconstruction with cable autografts is a common treatment technique, and repair with decellular nerve allograft is a newer option. The purpose of this study was to compare the functional outcomes of reconstruction with cable autografts with those of matched-diameter decellular nerve allografts to evaluate the relative importance of diameter as well as the autograft-versus-allograft nature of the reconstruction. Methods: A unilateral 10-mm sciatic nerve defect was created in 81 genetically identical male Lewis rats and then repaired with a reverse autograft, 4 or 5 sural nerve cable autografts, or a matched-diameter decellular nerve allograft. In each group, at each time point (12, 16, and 20 weeks), all 9 animals underwent functional testing and 5 of the 9 underwent histologic analysis. Functional testing included bilateral measurements of the isometric tetanic force of the tibialis anterior (primary outcome), the weight of the tibialis anterior, and the gastrocnemius compound muscle action potential (CMAP) latency. Histologic evaluation included an axon count as well as measurement of the axon density, fiber diameter, myelin thickness, and G-ratio. Results: The repair groups did not differ significantly in terms of isometric tetanic force, muscle weight, or CMAP latency, but these measurements did differ significantly according to the time after surgery (p < 0.05). The isometric tetanic force percent recovery (width of the 95% confidence interval) for the reverse autograft, cable autograft, and decellular nerve allograft was 57.7% (15.6%), 57.0% (23.4%), and 56.0% (19.7%), respectively, at 12 weeks; 69.1% (14.7%), 65.6% (18.5%), and 65.9% (29.1%) at 16 weeks; and 72.5% (18.2%), 73.7% (25.6%), and 71.8% (22.4%) at 20 weeks. Isometric tetanic force and muscle weight recovery were greater and CMAP latency was shorter at 20 and 16 weeks after surgery than they were at 12 weeks. The treatment type did not affect any of the histologic outcomes. Conclusions: In this animal study, we found that matched-diameter decellular nerve allograft was not significantly different from reverse autograft or cable graft reconstruction in terms of function and histologic outcomes. These findings support decellular nerve allograft as a viable treatment option for nerve reconstruction. Clinical Relevance: This study showed that decellular nerve allograft was no different from cable or reverse autograft in terms of outcome measures in a rat sciatic nerve defect model. If these results are applicable clinically, it would obviate the need for autograft nerve harvest and its ensuing donor site morbidity.