Protective Effects of Inducible HO-1 on Oxygen Toxicity in Rat Brain Endothelial Microvessel Cells

BACKGROUND: Reperfusion in ischemia is believed to generate cytotoxic oxidative stress, which mediates reperfusion injury. These stress conditions can initiate lipid peroxidation and damage to proteins, as well as promote DNA strand breaks. As biliverdin and bilirubin produced by heme oxygenase isoform 1 (HO-1) have antioxidant properties, the production of both antioxidants by HO-1 may help increase the resistance of the ischemic brain to oxidative stress. In the present study, the survival effect of HO-1 was confirmed using hemin. METHODS: To confirm the roles of HO-1, carbon monoxide, and cyclic guanosine monophosphate further in the antioxidant effect of HO-1 and bilirubin, cells were treated with cycloheximide, desferoxamine, and zinc deuteroporphyrin IX 2,4 bis glycol, respectively. RESULTS: HO-1 itself acted as an antioxidant. Furthermore, iron, rather than carbon monoxide, was involved in the HO-1-mediated survival effect. HO-1 activity was also important in providing bilirubin as an antioxidant. CONCLUSION: Our results suggested that HO-1 helped to increase the resistance of the ischemic brain to oxidative stress.

Efficient culture system for human embryonic stem cells using autologous human embryonic stem cell-derived feeder cells

Human embryonic stem cells (hESCs) need feeder cells for their maintenance in an undifferentiated state. In conventional culture systems, mouse embryonic fibroblasts (MEFs) serve as feeder cells to maintain hESCs. However, the use of MEFs elevates the risk of transmitting mouse pathogens and thus limits the potential of hESCs in cell replacement therapy. Consequently, the use of human feeder cells would be an important step forward in this in vitro technology. To address this issue, we used fibroblast-like cells differentiated from the Miz-hES6 hESC line (Diff (Miz-hES6)) as feeder cells to support the in vitro growth of three hESC lines. Immunofluorescence microscopy and reverse transcription-PCR assessing the expression of undifferentiated hESC markers revealed all three hESC lines were maintained in an undifferentiated state. In vitro proliferation proceeded as efficiently as when the hESCs were cultured on MEFS. Moreover, karyotype analysis revealed the chromosomal normality of the hESC lines and the Diff (Miz-hES6) feeders themselves after even 50 passages. Furthermore, the hESC lines maintained their pluripotency since they remained capable of forming embryoid bodies (EBs) in vitro. Thus, hESC-derived fibroblast-like cells successfully support in vitro hESC propagation.

Recent Advances in Human Embryonic Stem Cell Research

The 21st century is considered as the era of Biotechnology (BT). Recently, the regenerative medicine using stem cells has been recognized as the future medicine, especially for the devastating diseases such as neurodegenerative diseases, heart disease, diabetes, infertility and liver diseases. Human embryonic stem cells (hESCs) are at the center of the stem cell research due to its ability to proliferate unlimitedly without differentiation (self-renewal) and to differentiate into the derivatives of all three germ layers including germ cells with appropriate treatments (pluripotency). A total of 173 hESC lines have been derived since the first derivation by Thomson et al. in 1998, and 70 hESC lines are currently available for distribution including hESC line (Miz-hES1) established at the MizMedi Hospital. The major goal of hESC research is to provide basic and clinical clues for cell replacement therapy, whose targets are aforementioned incurable diseases. One of the landmarks in hESC research is the derivation of a hESC line from a cloned human blastocyst, which has recently been done by Korean scientists. This made it possible to overcome the issue of immune-mediated rejection following cell replacement therapy using hESCs. Guided differentiation of hESCs into specific cell types by treating growth factors and drugs or by genetic manipulation by using overexpression or an RNAi knockdown system is one of the most active research areas. Combined efforts towards the guided differentiation of hESC into specific cell types and the cloning of hESC from a cloned human blastocyst will overcome a list of diseases hitherto considered to be incurable.