POSTN and acute kidney injury: Thus our results show that the kidney IRI already after 24 hours caused a pro-fibrotic shift in the pattern of expression of kidney genes and that the expression levels of the pro-fibrotic genes (Tgf-β1, Inhba and Periostin) 14 days after IRI were still significantly elevated in both NR and vehicle rats, indicating that NAD+ boosting did not protect against transition from AKI to chronic kidney fibrosis in IRI rat model.