ABSTRACT
Corneal stem/progenitor cells are typical adult stem/progenitor cells. The human cornea covers the front of the eyeball, which protects the eye from the outside environment while allowing vision. The location and function demand the cornea to maintain its transparency and to continuously renew its epithelial surface by replacing injured or aged cells through a rapid turnover process in which corneal stem/progenitor cells play an important role. Corneal stem/progenitor cells include mainly corneal epithelial stem cells, corneal endothelial cell progenitors and corneal stromal stem cells. Since the discovery of corneal epithelial stem cells (also known as limbal stem cells) in 1971, an increasing number of markers for corneal stem/progenitor cells have been proposed, but there is no consensus regarding the definitive markers for them. Therefore, the identification, isolation and cultivation of these cells remain challenging without a unified approach. In this review, we systematically introduce the profile of biological characterizations, such as anatomy, characteristics, isolation, cultivation and molecular markers, and clinical applications of the three categories of corneal stem/progenitor cells.
ABSTRACT
Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors involved in the regulation of lipid metabolism, energy production, and inflammation. It is well established that all of the three isoforms of PPARs expressed in the cardiomyocytes, and that PPARs are closely involved in the regulation of lipid metabolism and energy homeostasis as well as many other different aspects in the heart. We think that PPARs are very important therapeutic targets for drug development, however, the drugs targeting at PPARs meet some trouble in clinical practice, especially the reported side effects related to heart failure. This review summarizes different functions and mechanisms of each isoform in cardiac hypertrophy and heart failure, for the reason that if more efforts are made to investigate the interactions among different isoforms, minimize the off-target effects, and avoid PPARs-independent side effects, we can develop safer and more effective PPAR agonists for the clinical practice in the near future.