Biological character of human adipose-derived adult stem cells and influence of donor age on cell replication in culture

To investigate the biological character of human adipose-derived adult stem cells (hADAS cells) when cultured in vitro and the relationship between hADAS cell’s replication activity and the donor’s age factor, and to assess the stem cells as a new source for tissue engineering. hADAS cells are isolated from human adipose tissue of different age groups (from adolescents to olds: <20 years old, 21―40 years old, 41―60 years old and >61 years old groups). The protein markers (CD29, CD34, CD44, CD45, CD49d, HLA-DR, CD106) of hADAS cells were detected by flow cytometry (FCM) to identify the stem cell, and the cell cycle was examined for P20 hADAS cells to evaluate the safety of the subculture in vitro. The generative activity of hADAS cells in different age groups was also examined by MTT method. The formula “ log2T D = t logN t ? logN 0” was used to get the time doubling (TD) of the cells. The results showed that the cells kept heredity stabilization by chromosome analysis for at least 20 passages. The TD of these cells increased progressively by ageing, and the TD of the <20 years old group was lower than that of the >61 years old group (statistical analysis of variance (ANOVA), P=0.002, P<0.05). These find- ings suggested that a higher level of hADAS cells replication activity was found in the younger dona- tors, and they represent novel and valuable seed cells for studies of tissue engineering.

Circular RNAs in pulmonary hypertension:Emerging biological concepts and potential mechanism

Circular RNAs(circRNAs)are endogenous RNAs with a covalently closed single-stranded transcript.They are a novel class of genomic regulators that are linked to many important development and disease processes and are being pursued as clinical and therapeutic targets.Using the most powerful RNA sequencing and bioinformatics techniques,a large number of circRNAs have been identified and further functional studies have been performed.It is known that circRNAs act as potential biomarkers,sponges for microRNAs(miRNAs)and RNA-binding proteins(RBPs),and regulators of mRNA transcription.They also participate in the translation of peptides or proteins.Many types of circRNAs are dysregulated in plasma or lung tissues,and they may be involved in regulating the proliferation and apoptosis of pulmonary artery endothelial cells(PAECs)and pulmonary artery smooth muscle cells(PASMCs),leading to pulmonary vascular remodeling in pulmonary hypertension(PH).One possible mechanism is that circRNAs can regulate the function of PAECs and PASMCs by acting as miRNA sponge.However,other potential mechanisms of action of circRNAs are still being actively explored in PH.This paper presents a systematic review of the biogenesis,biological characterization,relevant underlying functions,and future perspectives for studies of circRNAs in the pathogenesis of PH.