TGFB1 and fibrosis: Strikingly, the intermittent systemic (i.p) or oral administration of SPION-RLX abrogated the ISO-induced interstitial LV collagen fibrosis (to ~ 2.0 ± 0.3%; Fig. 4B), myofibroblast accumulation (to 9–10 cells/field; Fig. 4C) and TGF-β1 expression levels (to 0.7 ± 0.1%; Fig. 4D) to an equivalent extent as Pump-RLX treatment, and to levels that were no different to that measured in saline-injected control mice.