Adequate biological models are a prerequisite to screening and development of probiotic drugs. In the present study, Caco-2 cell line is reviewed as a model for analyzing properties of probiotics. This cell culture possesses all the characteristics necessary for evaluating the effects of probiotic drugs on a wide range of both intracellular processes and intercellular interactions. Informativeness of Caco-2 cells is in the focus of the present review.

Systemic biomarkers (i.e. biomarkers of functioning of cellular pathways) offer a broad spectrum of diagnostic capabilities. There are several approaches to using systemic biomarkers that derive from exact needs of a researcher or a clinical specialist. First, analyzing a multifunctional and multi-systemic pathway in circulating cells (e.g. leukocytes) allows to gather generalized information on functioning of the organism. Second, there are numerous pathways that, even still in circulating cells, allow to assess risks of developing or stage of development of numerous diseases, including the leaders of non-infection diseases mortality-cardiovascular diseases. Third, biopsy specimens can readily be used to assess the exact signaling type of a disease (especially cancer) thus helping in selecting the best treatment option. Due to unique properties of the human oxidative status pathways that are discussed in the present chapter, diagnostics specialists are now acquiring an allin-one toolbox for profiling and detecting almost any non-infectious and a broad range of infectious diseases. In addition to properties of the human oxidative status pathways opening these possibilities, this chapter considers exact systemic biomarkers deriving from this approach, reveals some examples of usage of the resulting diagnostic technology and provides instances of successful clinical application of the systemic biomarker approach.