Background & AimsThe lack of a preclinical model of progressive non-alcoholic steatohepatitis (NASH) that recapitulates human disease is a barrier to therapeutic development.MethodsA stable isogenic cross between C57BL/6J (B6) and 129S1/SvImJ (S129) mice were fed a high fat diet with ad libitum consumption of glucose and fructose in physiologically relevant concentrations and compared to mice fed a chow diet and also to both parent strains.ResultsFollowing initiation of the obesogenic diet, B6/129 mice developed obesity, insulin resistance, hypertriglyceridemia and increased LDL-cholesterol. They sequentially also developed steatosis (4–8 weeks), steatohepatitis (16–24 weeks), progressive fibrosis (16 weeks onwards) and spontaneous hepatocellular cancer (HCC). There was a strong concordance between the pattern of pathway activation at a transcriptomic level between humans and mice with similar histological phenotypes (FDR 0.02 for early and 0.08 for late time points). Lipogenic, inflammatory and apoptotic signaling pathways activated in human NASH were also activated in these mice. The HCC gene signature resembled the S1 and S2 human subclasses of HCC (FDR 0.01 for both). Only the B6/129 mouse but not the parent strains recapitulated all of these aspects of human NAFLD.ConclusionsWe here describe a diet-induced animal model of non-alcoholic fatty liver disease (DIAMOND) that recapitulates the key physiological, metabolic, histologic, transcriptomic and cell-signaling changes seen in humans with progressive NASH.Lay summaryWe have developed a diet-induced mouse model of non-alcoholic steatohepatitis (NASH) and hepatic cancers in a cross between two mouse strains (129S1/SvImJ and C57Bl/6J). This model mimics all the physiological, metabolic, histological, transcriptomic gene signature and clinical endpoints of human NASH and can facilitate preclinical development of therapeutic targets for NASH.

iPSCs, and iPSC-EVs were injected intramyocardially at 48 hours after a reperfused myocardial infarction in mice. Compared with vehicle-injected mice, both iPSC-and iPSC-EV-treated mice exhibited improved left ventricular function at 35 d after myocardial infarction, albeit iPSC-EVs rendered greater improvement. iPSC-EV injection also resulted in reduction in left ventricular mass and superior perfusion in the infarct zone.Both iPSCs and iPSC-EVs preserved viable myocardium in the infarct zone, whereas reduction in apoptosis was significant with iPSC-EVs. iPSC injection resulted in teratoma formation, whereas iPSC-EV injection was safe. Conclusions: iPSC-derived

Recent observational studies in humans suggest that circulating FGF23 is independently associated with cardiac hypertrophy and increased mortality, but it is unknown whether FGF23 can directly alter cardiac function. We found that FGF23 significantly increased cardiomyocyte cell size in vitro, the expression of gene markers of cardiac hypertrophy, and total protein content of cardiac muscle. In addition, FGFR1 and FGFR3 mRNA were the most abundantly expressed FGF receptors in cardiomyocytes, and the coreceptor ␣-klotho was expressed at very low levels. We tested an animal model of chronic kidney disease (Col4a3 Ϫ/Ϫ mice) that has elevated serum FGF23. We found elevations in common hypertrophy gene markers in Col4a3 Ϫ/Ϫ hearts compared with wild type but did not observe changes in wall thickness or cell size by week 10. However, the Col4a3 Ϫ/Ϫ hearts did show reduced fractional shortening (Ϫ17%) and ejection fraction (Ϫ11%). Acute exposure of primary cardiomyocytes to FGF23 resulted in elevated intracellular Ca 2ϩ ([Ca 2ϩ ]i; F/Fo ϩ 86%) which was blocked by verapamil pretreatment. FGF23 also increased ventricular muscle strip contractility (67%), which was inhibited by FGF receptor antagonism. We hypothesize that although FGF23 can acutely increase [Ca 2ϩ ]i, chronically this may lead to decreases in contractile function or stimulate cardiac hypertrophy, as observed with other stress hormones. In conclusion, FGF23 is a novel bone/heart endocrine factor and may be an important mediator of cardiac Ca 2ϩ regulation and contractile function during chronic kidney disease. fibroblast growth factor 23; pathological cardiac hypertrophy; chronic kidney disease; Col4a3; cardiac function; ␣-klotho FIBROBLAST GROWTH FACTOR 23 (FGF23) is a hormone released primarily by osteocytes (2, 4, 14, 38) that functions to regulate phosphate and vitamin D homeostasis through direct actions on the kidney and parathyroid (2). Although an endocrine axis has been established between bone and kidney, a new paradigm is emerging in which FGF23 could be important in establishing an endocrine axis between bone and heart. Circulating levels of FGF23 are markedly elevated 100-to 1,000-fold in patients with chronic kidney disease (CKD) (24, 31) and are independently associated with cardiovascular morbidity and mortality (8,22,26,34,35,48,52). Specifically, an association between left ventricular (LV) hypertrophy and serum FGF23 levels has been established in CKD patients (20,36,52).Nevertheless, despite strong associations between FGF23 and adverse outcomes, it remains relatively unknown whether FGF23 is simply a marker of cardiac disease risk or a direct mediator of cardiac pathology and cardiac performance. Only one study to date has analyzed the direct effects of FGF23 on the heart both in vitro and in vivo (13). This important work by Faul et al. (13) shows that FGF23 can directly induce hypertrophy in isolated neonatal cardiomyocytes as well as with intramyocardial FGF23 injections. These authors also demonstrated that a FGF receptor (FGF...

Rationale The role of interleukin (IL)-6 in the pathogenesis of cardiac myocyte hypertrophy remains controversial. Objective To conclusively determine whether IL-6 signaling is essential for the development of pressure overload-induced left ventricular (LV) hypertrophy, and to elucidate the underlying molecular pathways. Methods and Results Wild-type (WT) and IL-6 knockout (IL-6−/−) mice underwent sham surgery or transverse aortic constriction (TAC) to induce pressure overload. Serial echocardiograms and terminal hemodynamic studies revealed attenuated LV hypertrophy and superior preservation of LV function in IL-6−/− mice after TAC. The extents of LV remodeling, fibrosis, and apoptosis were reduced in IL-6−/− hearts after TAC. Transcriptional and protein assays of myocardial tissue identified CaMKII and STAT3 activation as important underlying mechanisms during cardiac hypertrophy induced by TAC. The involvement of these pathways in myocyte hypertrophy was verified in isolated cardiac myocytes from WT and IL-6−/− mice exposed to pro-hypertrophy agents. Furthermore, overexpression of CaMKII in H9c2 cells increased STAT3 phosphorylation, and exposure of H9c2 cells to IL-6 resulted in STAT3 activation that was attenuated by CaMKII inhibition. Together these results identify the importance of CaMKII-dependent activation of STAT3 during cardiac myocyte hypertrophy via IL-6 signaling. Conclusions Genetic deletion of IL-6 attenuates TAC-induced LV hypertrophy and dysfunction, indicating a critical role played by IL-6 in the pathogenesis of LV hypertrophy in response to pressure overload. CaMKII plays an important role in IL-6-induced STAT3 activation and consequent cardiac myocyte hypertrophy. These findings may have significant therapeutic implications for LV hypertrophy and failure in patients with hypertension.