Animal Models and Methods of Myocardial Infarction Induction and the Role of Tissue Engineering in the Regeneration of Damaged Myocardium.

The introduction of an experimental animal model for myocardial infarction (MI) has particular importance. Research done on large animals provides valuable information for the researchers because of the similar characteristics of their hearts compared to humans, but the cost of purchasing and maintaining them is high. In comparison, using small animals has advantages, such as they are easy to work with and have low purchase and maintenance costs. However, in some of these animals, due to less similarity of the heart to humans, they cannot simulate the natural pathogenesis of human MI. Moreover, there are different methods for the induction of MI in animals; each has its own advantages and disadvantages. However, a method must be chosen to simulate the natural pathogenesis of MI with minimal complication. Currently, attempts are being made for myocardial regeneration after MI using the direct transplantation of stem cells or an engineered scaffold. The scaffold creates a 3D ambiance for the cultured cells. The task of tissue engineering is to optimize the scaffold with appropriate systems for the separation, proliferation, and differentiation of the desired cells until they are capable of promoting the threedimensional and appropriate growth of the tissue. The purpose of tissue engineering in cardiac is the use of scaffolds and cells in the damaged area, followed by the improvement of the heart function through automatic pulsation, communication with the host vessels, and electrical coupling with the myocardium, eventually creating a force to increase the heart function.

The Therapeutic Potential of Differentiated Lung Cells from Embryonic Stem Cells in Lung Diseases.

Lung diseases cause great morbidity and mortality. The choice of effective medical treatment is limited and the number of lung diseases are difficult to treat with current treatments. The embryonic stem cells (ESCs) have the potential to differentiate into cell types of all three germinal layers, including lung epithelial cells. So they can be a potential source for new cell therapies for hereditary or acquired diseases of the airways and lungs. One method for treatment of lung diseases is cell therapy and the use of ESCs that can replace the damaged epithelial and endothelial cells. Progress using ESCs has developed slowly for lung regeneration because differentiation of lung cells from ESCs is more difficult as compared to differentiation of other cells. The review studies the therapeutic effects of differentiated lung cells from embryonic stem cells in lung diseases. There are few studies of differentiation of ESCs into a lineage of respiratory and then investigation of this cell in experimental model of lung diseases.

Preparation and Evaluation of Contact Lenses Embedded with Polycaprolactone-Based Nanoparticles for Ocular Drug Delivery.

To improve the efficiency of topical ocular drug administration, we focused on development of a nanoparticles loaded contact lens to deliver the hydrophobic drug over a prolonged period of time. The cross-linked nanoparticles based on PCL (poly ε-caprolactone), 2-hydroxy ethyl methacrylate (HEMA), and poly ethylene glycol diacrylate (PEG-DA) were prepared by surfactant-free miniemulsion polymerization. The lens material was prepared through photopolymerization of HEMA and N-vinylpyrrolidone (NVP) using PEG-DA as the cross-linker. Effects of nanoparticles loading on critical contact lens properties such as transparency, water content, modulus and ion and oxygen permeabilities were studied. Nanoparticles and hydrogel showed high viability, indicating the absence of cytotoxicity and stimulatory effect. Drug release studies revealed that the hydrogel embedded with nanoparticles released the drug for a period of 12 days. The results of this study provide evidence that nanoparticles loaded hydrogels could be used for extended delivery of loteprednol etabonate and perhaps other drugs.