Sources of β-cells for human cell-based therapies for diabetes

PAR-4: a possible new target for age-related disease

INTRODUCTION

Apoptosis plays an important role in age-related disease, and prostate apoptosis response-4 (PAR-4) is a novel apoptosis-inducing factor that regulates apoptosis in most cells. Recent studies suggest that PAR-4 plays an important role in the progression of many age-related diseases. This review highlights the significance of PAR-4 and builds a strong case supporting its role as a possible therapeutic target in age-related disease.

AREAS COVERED

This review covers the advancements over the last 15 years with respect to PAR-4 and its significance in age-related disease. Additionally, it provides knowledge regarding the significance of PAR-4 in age-related disease as well as its role in apoptotic signaling pathways, endoplasmic reticulum (ER) stress, and other mechanisms that may induce age-related disease.

EXPERT OPINION

PAR-4 may be a potential therapeutic target that can trigger selective apoptosis in cancer cells. It is induced by ER stress and increased ER stress, and it is involved in the activity of the dopamine D2 receptor. Abnormal expression of PAR-4 may be associated with cardiovascular disease and diabetes. PAR-4 agonists and inhibitors must be identified before gene therapy can commence.

The stages of type 1A diabetes

We can now predict the development of type 1 diabetes in man because it is a chronic autoimmune disorder with defined stages of disease. We can also readily prevent the disorder in animal models. A major goal is safe prevention in man, and for this we will almost certainly need a better understanding of pathogenesis, coupled with rigorous clinical trials.

Human umbilical cord blood-derived f-macrophages retain pluripotentiality after thrombopoietin expansion

We have previously characterized a new type of stem cell from human peripheral blood, termed fibroblast-like macrophage (f-Mphi). Here, using umbilical cord blood as a source, we identified cells with similar characteristics including expression of surface markers (CD14, CD34, CD45, CD117, and CD163), phagocytosis, and proliferative capacity. Further, thrombopoietin (TPO) significantly stimulated the proliferation of cord blood-derived f-Mphi (CB f-Mphi) at low dosage without inducing a megakaryocytic phenotype. Additional experiments demonstrated that TPO-expanded cord blood-derived f-Mphi (TCB f-Mphi) retained their surface markers and differentiation ability. Treatment with vascular endothelial cell growth factor (VEGF) gave rise to endothelial-like cells, expressing Flt-1, Flk-1, von Willebrand Factor (vWF), CD31, acetylated low density lipoprotein internalization, and the ability to form endothelial-like cell chains. In the presence of lipopolysaccharide (LPS) and 25 mM glucose, the TCB f-Mphi differentiated to express insulin mRNA, C-peptide, and insulin. In vitro functional analysis demonstrated that these insulin-positive cells could release insulin in response to glucose and other secretagogues. These findings demonstrate a potential use of CB f-Mphi and may lead to develop new therapeutic strategy for treating dominant disease.

Embryonic stem cells for basic research and potential clinical applications in cardiology

Embryonic stem (ES) cells are pluripotent, possessing the unique property to differentiate into any somatic cell type while retaining the ability to proliferate indefinitely. Due to their ability to recapitulate embryonic differentiation, ES cells are an ideal tool to study the process of early embryogenesis in vitro. Signalling cascades and genes involved in differentiation can be easily studied, and functional genomics approaches aim to identify the regulatory networks underlying lineage commitment. Their unique ability to differentiate into any cell type make ES cells a prime candidate for cell replacement therapy (CRT) of various degenerative disorders. Results from various disease models are promising and have demonstrated their principal suitability as a therapeutic agent in diseases such as myocardial infarctions, diabetes mellitus and Parkinson's disease. Prior to clinical trials in humans, two issues remain to be solved: due to their high proliferative potential, ES cells can form teratocarcinomas in the recipient, and depending on the source of the cells, ES cell grafts may be rejected by the host organism. This review discusses the current state of basic ES cell research with a focus on cardiac differentiation and gives an overview of their use in CRT approaches.