Vitrification in human and domestic animal embryology: work in progress.

According to the analysis of papers published in major international journals, rapidly increasing application of vitrification is one of the greatest achievements in domestic animal and especially human embryology during the first decade of our century. This review highlights factors supporting or hampering this progress, summarises results achieved with vitrification and outlines future tasks to fully exploit the benefits of this amazing approach that has changed or will change many aspects of laboratory (and also clinical) embryology. Supporting factors include the simplicity, cost efficiency and convincing success of vitrification compared with other approaches in all species and developmental stages in mammalian embryology, while causes that slow down the progress are mostly of human origin: inadequate tools and solutions, superficial teaching, improper application and unjustified concerns resulting in legal restrictions. Elimination of these hindrances seems to be a slower process and more demanding task than meeting the biological challenge. A key element of future progress will be to pass the pioneer age, establish a consensus regarding biosafety requirements, outline the indispensable features of a standard approach and design fully-automated vitrification machines executing all phases of the procedure, including equilibration, cooling, warming and dilution steps.