Phthalates are esters of phthalic acid used industrially as plastic additives, however, these are not covalently bound to the polymer matrix and therefore can be released to the environment. The aim of this study was to evaluate the effect of four phthalates: dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), diethyl phthalate (DEP) and diethylhexyl phthalate (DEHP) on the in vitro expansion of human hematopoietic cells from umbilical cord blood. For this, 0.5 9 10 6 cells/mL were exposure to concentrations ranging from 0.1 to 100 lg/mL and the total cell expansion was determined after 14 days of culture in IMDM-cytokines medium. The control cultures attained 1.31 ± 0.21 9 10 6 cell/mL, whereas the cultures exposed to DBP, BBP and DEHP showed a reduction from 23 to 81%, 17 to 69% and 15 to 93.5%, respectively. DEP did not affect the total cell expansion. The most significant decrease on total cell expansion was observed at 0.1 lg/mL DBP, 100 lg/mL BBP and 10 lg/mL DEHP (p \ 0.05). Additionally, the effect of these compounds on the expansion of hematopoietic progenitors was analyzed by clonogenic assays as colony forming units (CFU). The CFU decreased considerably compared with respect to the control cultures. The reduction was 74.6 and 99.1% at 10 and 100 lg/mL DBP respectively, whereas 100 lg/mL BBP and 100 lg/mL DEHP reduced the CFU expansion in 97.1% and 81%, respectively. Cultures exposed to DEP did not show significant differences. The results demonstrate the toxicity of DBP, BBP and DEHP on the human hematopoietic stem cells.

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In this work, we evaluated the expansion of human hematopoietic stem cells from umbilical cord blood in roller bottles. The Iscove's modified Dulbecco's medium, the Stem Pro 34-SFM medium, and the L-15 Leibovitz's medium for cultures in CO(2)-free atmosphere were assessed. At day 5 of culture, total colony forming unit expansions of 14.44 ± 3.74, 11.20 ± 6.37, and 17.25 ± 3.65-folds were attained, respectively. The expansion reached using L-15 medium in roller bottles was around 10 times higher than that achieved in the static control cultures. To our knowledge, this is the first report of cultures in CO(2)-free atmosphere to expand cord blood human hematopoietic stem cells and it opens a new branch of possibilities for culturing and clinical applications.

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Background: Ultraviolet B (UVB) causes photoaging of the skin, the appearance of wrinkles, spots, and alteration of the skin barrier. The main cells in the most superficial layer of the skin are the keratinocytes; these cells play an important role in protecting this organ.Objective: The present study aimed to investigate the antioxidant activity of the hydrolysates from kafirin to inhibit UVB-induced responses in human keratinocytes cells (HaCaT).Methods: Kafirin hydrolysates were produced by enzymatic hydrolysis with alcalase.The activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), in the HaCaT cell line in the presence of UVB and the effects of the hydrolysates against the UVB-induced response were evaluated. Furthermore, the peptides that were generated by hydrolysis were identified in silico using the BIOPEP database.Results: Two protein sequences were identified (α-kafirin and the precursor protein of α-kafirin), in the kafirin extract. A degree of hydrolysis of 18.8% was obtained by hydrolyzing the kafirin extract with alcalase. The kafirin hydrolysates avoided the decrease in endogenous antioxidant enzymes such as SOD, CAT, and GPx reducing the oxidative stress generated by UVB. Using the BIOPEP-UWM database, we found 102 peptide sequences, and it has shown that the peptides have a large amount of hydrophobic amino acids such as proline, alanine, and glutamine, and amino acids with high antioxidant capacity. Conclusion:These results suggest that the kafirin hydrolysates can be used as antioxidant agents to ameliorate UVB-induced skin keratinocytes cells' response in vitro, providing an alternative against UVB-induced photoaging.