Bile acids play a significant role in the digestion of nutrients. In addition, bile acids perform a signaling function through their blood-circulating fraction. They regulate the activity of nuclear and membrane receptors, located in many tissues. The gut microbiota is an important factor influencing the effects of bile acids via enzymatic modification. Depending on the rate of healthy and pathogenic microbiota, a number of bile acids may support lipid and glucose homeostasis as well as shift to more toxic compounds participating in many pathological conditions. Thus, bile acids can be possible biomarkers of human pathology. However, the chemical structure of bile acids is similar and their analysis requires sensitive and specific methods of analysis. In this review, we provide information on the chemical structure and the biosynthesis of bile acids, their regulation, and their physiological role. In addition, the review describes the involvement of bile acids in various diseases of the digestive system, the approaches and challenges in the analysis of bile acids, and the prospects of their use in omics technologies.

Human platelet lysate (HPL) is a promising alternative to fetal calf serum (FCS) for the expansion of adipose tissue mesenchymal stromal cells (AT-MSCs) for translational medicine applications. However, some biological effects of HPL are still to be elucidated. We aimed to compare complex characteristics, such as cell morphology, proliferative activity, differentiation potential, and especially monolayer recovery, DNA integrity, and the gene expression pattern, between AT-MSCs cultured with HPL or FCS. Primary AT-MSC cultures were expanded in medium containing FCS or pooled HPL. Cell growth and proliferation were estimated by cell doubling time and the monolayer formation rate, while migration was assessed by wound-healing assay. The capacity for adipogenic and osteogenic differentiation was evaluated by alkaline phosphatase and Oil Red O staining. DNA integrity was evaluated by comet assay, and analysis of gene expression by real-time PCR. Media supplemented with HPL or FCS provided a similar surface immunophenotype, cell morphology (except some cell dimensions and a bigger colony size in HPL), DNA integrity, and rate of wound healing. Meanwhile, AT-MSC proliferated more intensively in HPL-supplemented media (especially at 5% HPL) and had a reduced doubling population time. AT-MSC in HPL had increased adipogenic potential and similar osteogenic potential in comparison with FCS. Our results indicate the feasibility and evident prospects for the use of pooled HPL as an alternative to FCS and safe non-xenogenic growth supplement for ex vivo expansion of clinical-grade AT-MSCs for regenerative medicine purposes.