Nestin(+) stem cells independently contribute to neural remodelling of the ischemic heart

Recent studies have revealed the existence of multipotent nestin-immunoreactive cells in the adult mammalian heart. These cells were recruited to infarct site following ischemic injury and differentiated to a vascular lineage leading to de novo blood vessel formation. Here, we show that a sub-population of cardiac resident nestin(+) cells can further differentiate to a neuronal-like fate in vivo following myocardial infarction. In the ischemically damaged rat heart, neurofilament-M(+) fibres were detected innervating the peri-infarct/infarct region and the preponderance of these fibres were physically associated with processes emanating from nestin(+) cells. One week after isogenic heterotopic cardiac transplantation, the beating transplanted rat heart was devoid of neurofilament-M(+) fibre staining. The superimposition of an ischemic insult to the transplanted heart led to the de novo synthesis of neurofilament-M(+) fibres by cardiac resident nestin(+) cells. Nerve growth factor infusion and the exposure of normal rats to intermittent hypoxia significantly increased the density of neurofilament-M(+) fibres in the heart. However, these newly formed neurofilament-M(+) fibres were not physically associated with nestin(+) processes. These data highlight a novel paradigm of reparative fibrosis as a subpopulation of cardiac resident nestin(+) cells directly contributed to neural remodelling of the peri-infarct/infarct region of the ischemically damaged rat heart via the de novo synthesis of neurofilament-M fibres. J. Cell. Physiol. 226: 1157–1165, 2011. © 2010 Wiley-Liss, Inc.