(From EurekAlert). The production of blood vessels is one major obstacle to the creation of larger engineered replacement tissue, such as organs or portions of organs. Progress is being made, however: "With heart disorders affecting individuals globally and contributing to increasing mortality rates, there has been a need to develop new treatment options. One of the specific challenges in the field of tissue engineering is to produce blood vessels within heart muscle tissue. In this study, the researchers were successful in this task. Their live models showed significant improvement in heart function, particularly in the amount of vascularization throughout the implanted sections. Further, the tissue engineered construct remained viable even after the three-week implantation period, maintaining cardiac specific function."