Μελέτη του ρόλου του υποδοχέα RPTP β/ζ στην καρδιακή λειτουργία in vivo

Angiogenesis is the phenomenon under which new blood vessels are being created either from pre-existing blood vessels or de novo. This process is important for the development of both physiological (tissue growth and wound healing) and pathological processes (development and metastasis of malignancies, obesity, arterial atheromatosis, chronic inflammatory conditions etc). Receptor tyrosine phosphatase beta/ zeta (RPTPβ/ζ) and its ligands, pleiotrophin and midkine, are molecules that play an important regulatory role regarding the phenomenon of angiogenesis. Furthermore, it has been found that these molecules are implicated into a multitude of other pathophysiological processes such as schizophrenia, Parkinson’s disease, tissue remodeling after ischemia and the development of atherotic plaques. An increasing amount of research data suggests that both pleiotrophin and midkine do play a role in the development of heart failure, a syndrome that is a major cause of high morbidity and mortality rates worldwide, on the scale of a proper epidemic. However, currently there is no equal amount of data regarding the role of RPTPβ/ζ in the development of this syndrome.In this work, the role of RPTPβ/ζ in the cardiac function was studied by using wild type (WT or Ptprz1+/+) and knock – out (KO or Ptprz1-/-) mice. By applying proper lectin staining on cardiac tissue samples from mice aged 3 weeks old, it has been found that angiogenesis is significantly increased in KO mice, but without statistically important differences regarding the number of cells and the size of the cellular transectional areas. Subsequently, cardiac transthoracic ultrasound on mice aged 3 months old showed impaired systolic left ventricular function on KO mice, with no actual differences regarding the expression of proteins of the extracellular matrix on Western blot analysis of homogenized cardiac tissue. Collectively, these findings suggest the potential involvement of RPTPβ/ζ in cardiac function.