Purpose. To construct a full-thickness biological substitute of the rabbit cornea by tissue engineering.

The objective was to study the effectiveness of a commercially available collagen conduit filled with fibrin-agarose hydrogels alone or with fibrin-agarose hydrogels containing autologous adipose-derived mesenchymal stem cells (ADMSCs) in a rat sciatic nerve injury model. A 10 mm gap was created in the sciatic nerve of 48 rats and repaired using saline-filled collagen conduits or collagen conduits filled with fibrin-agarose hydrogels alone (acellular conduits) or with hydrogels containing ADMSCs (ADMSC conduits). Nerve regeneration was assessed in clinical, electrophysiological and histological studies. Clinical and electrophysiological outcomes were more favorable with ADMSC conduits than with the acellular or saline conduits, evidencing a significant recovery of sensory and motor functions. Histological analysis showed that ADMSC conduits produce more effective nerve regeneration by Schwann cells, with higher remyelination and properly oriented axonal growth that reached the distal areas of the grafted conduits, and with intensely positive expressions of S100, neurofilament and laminin. Extracellular matrix was also more abundant and better organized around regenerated nerve tissues with ADMSC conduits than those with acellular or saline conduits. Clinical, electrophysiological and histological improvements obtained with tissue-engineered ADMSC conduits may contribute to enhancing axonal regeneration by Schwann cells.

Purpose.: Decellularization of animal corneas is a promising method for the development of artificial human corneas by tissue engineering. In this study, two different decellularization protocols were evaluated to determine which one is able to best preserve the histologic structure, composition, and optical behavior of decellularized porcine corneas. Then, these corneas were recellularized with human keratocytes to obtain a partial human corneal substitute. Methods.: Two different decellularization protocols were applied, using NaCl and SDS, to determine which one is able to best preserve the histologic structure, composition, and optical behavior of the decellularized corneas. Then, those decellularized corneas that showed the most appropriate results were recellularized with human keratocytes and evaluated at the histologic, biochemical, and optical levels for use in regenerative medicine. Results.: The results showed that 1.5 M NaCl treatment of porcine corneas is able to generate an acellular corneal stroma with adequate histologic and optical properties and that human keratocytes are able to penetrate and spread within this scaffold with proper levels of cell differentiation. In contrast, 0.1% SDS treatment of porcine corneas resulted in high levels of fibril disorganization and poor optical behavior of these corneas. Conclusions.: In conclusion, the authors suggest that the decellularization of animal corneas with 1.5 M NaCl represents a useful method for the development of human bioengineered corneas with therapeutic potential.

The structure and function of peripheral nerves can be affected by a range of conditions with severe consequences in these patients. Currently, there are several surgical techniques available to treat peripheral nerve defects. Direct repair is the preferred treatment for short nerve gaps, and nerve autografting is the gold standard in critical nerve defects. The autografting is not always available, and the use of allograft, decellularized allograft and nerve conduits are often used with variable success. During the recent years, several outcomes were achieved in peripheral nerve tissue engineering. Promising experimental results have been demonstrated with this novel generation of nerve conduits, mainly composed by biodegradables materials in combination with intraluminal fillers, growth factors and different cell sources.

Background: Desmin ( DES ) mutations cause severe skeletal and cardiac muscle disease with heterogeneous phenotypes. Recently, DES mutations were described in patients with inherited arrhythmogenic right ventricular cardiomyopathy/dysplasia, although their cellular and molecular pathomechanisms are not precisely known. Our aim is to describe clinically and functionally the novel DES -p.Glu401Asp mutation as a cause of inherited left ventricular arrhythmogenic cardiomyopathy/dysplasia. Methods: We identified the novel DES mutation p.Glu401Asp in a large Spanish family with inherited left ventricular arrhythmogenic cardiomyopathy/dysplasia and a high incidence of adverse cardiac events. A full clinical evaluation was performed on all mutation carriers and noncarriers to establish clinical and genetic cosegregation. In addition, desmin, and intercalar disc–related proteins expression were histologically analyzed in explanted cardiac tissue affected by the DES mutation. Furthermore, mesenchymal stem cells were isolated and cultured from 2 family members with the DES mutation (1 with mild and 1 with severe symptomatology) and a member without the mutation (control) and differentiated ex vivo to cardiomyocytes. Then, important genes related to cardiac differentiation and function were analyzed by real-time quantitative polymerase chain reaction. Finally, the p.Glu401Asp mutated DES gene was transfected into cell lines and analyzed by confocal microscopy. Results: Of the 66 family members screened for the DES -p.Glu401Asp mutation, 23 of them were positive, 6 were obligate carriers, and 2 were likely carriers. One hundred percent of genotype-positive patients presented data consistent with inherited arrhythmogenic cardiomyopathy/dysplasia phenotype with variable disease severity expression, high-incidence of sudden cardiac death, and absence of skeletal myopathy or conduction system disorders. Immunohistochemistry was compatible with inherited arrhythmogenic cardiomyopathy/dysplasia, and the functional study showed an abnormal growth pattern and cellular adhesion, reduced desmin RNA expression, and some other membrane proteins, as well, and desmin aggregates in transfected cells expressing the mutant desmin. Conclusions: The DES -p.Glu401Asp mutation causes predominant inherited left ventricular arrhythmogenic cardiomyopathy/dysplasia with a high incidence of adverse clinical events in the absence of skeletal myopathy or conduction system disorders. The pathogenic mechanism probably corresponds to an alteration in desmin dimer and oligomer assembly and its connection with membrane proteins within the intercalated disc.

Development of human skin substitutes by tissue engineering may offer new therapeutic alternatives to the use of autologous tissue grafts. For that reason, it is necessary to investigate and develop new biocompatible biomaterials that support the generation of a proper human skin construct. In this study, we generated a novel model of bioengineered human skin substitute using human cells obtained from skin biopsies and fibrin-agarose biomaterials and we evaluated this model both at the ex vivo and the in vivo levels. Once the dermal fibroblasts and the epithelial keratinocytes were isolated and expanded in culture, we used fibrin-agarose scaffolds for the development of a full-thickness human skin construct, which was evaluated after 1, 2, 3 and 4 weeks of development ex vivo. The skin substitutes were then grafted onto immune-deficient nude mice and analyzed at days 10, 20, 30 and 40 postimplantation using transmission electron microscopy, histochemistry and immunofluorescence. The results demonstrated that the fibrin-agarose artificial skin had adequate biocompatibility and proper biomechanical properties. A proper development of both the bioengineered dermis and epidermis was found after 30 days in vivo, although the tissues kept ex vivo and those implanted in the animal model for 10 or 20 days showed lower levels of differentiation. In summary, our model of fibrin-agarose skin equivalent was able to reproduce the structure and histological architecture of the native human skin, especially after long-term in vivo implantation, suggesting that these tissues could reproduce the native skin.