Folic acid reduces doxorubicin-induced cardiomyopathy by modulating endothelial nitric oxide synthase.

The use of doxorubicin (DOXO) as a chemotherapeutic drug has been hampered by cardiotoxicity leading to cardiomyopathy and heart failure. Folic acid (FA) is a modulator of endothelial nitric oxide (NO) synthase (eNOS), which in turn is an important player in diseases associated with NO insufficiency or NOS dysregulation, such as pressure overload and myocardial infarction. However, the role of FA in DOXO-induced cardiomyopathy is poorly understood. The aim of this study was to test the hypothesis that FA prevents DOXO-induced cardiomyopathy by modulating eNOS and mitochondrial structure and function. Male C57BL/6 mice were randomized to a single dose of DOXO (20 mg/kg intraperitoneal) or sham. FA supplementation (10 mg/day per oral) was started 7 days before DOXO injection and continued thereafter. DOXO resulted in 70% mortality after 10 days, with the surviving mice demonstrating a 30% reduction in stroke volume compared with sham groups. Pre-treatment with FA reduced mortality to 45% and improved stroke volume (both P < 0.05 versus DOXO). These effects of FA were underlain by blunting of DOXO-induced cardiomyocyte atrophy, apoptosis, interstitial fibrosis and impairment of mitochondrial function. Mechanistically, pre-treatment with FA prevented DOXO-induced increases in superoxide anion production by reducing the eNOS monomer:dimer ratio and eNOS S-glutathionylation, and attenuated DOXO-induced decreases in superoxide dismutase, eNOS phosphorylation and NO production. Enhancing eNOS function by restoring its coupling and subsequently reducing oxidative stress with FA may be a novel therapeutic approach to attenuate DOXO-induced cardiomyopathy.

Intralipid protects the heart in late pregnancy against ischemia/reperfusion injury via Caveolin2/STAT3/GSK-3ß pathway.

BACKGROUND: We recently demonstrated that the heart of late pregnant (LP) rodents is more prone to ischemia/reperfusion (I/R) injury compared to non-pregnant rodents. Lipids, particularly polyunsaturated fatty acids, have received special attention in the field of cardiovascular research. Here, we explored whether Intralipid (ITLD) protects the heart against I/R injury in LP rodents and investigated the mechanisms underlying this protection. METHODS AND RESULTS: In-vivo female LP rat hearts or ex-vivo isolated Langendorff-perfused LP mouse hearts were subjected to ischemia followed by reperfusion with PBS or ITLD (one bolus of 5mg/kg of 20% in in-vivo and 1% in ex-vivo). Myocardial infarct size, mitochondrial calcium retention capacity, genome-wide expression profiling, pharmacological inhibition and co-immunoprecipitation were performed. One bolus of ITLD at reperfusion significantly reduced the in-vivo myocardial infarct size in LP rats (23.3±2% vs. 55.5±3.4% in CTRL, p<0.01). Postischemic administration of ITLD also protected the LP hearts against I/R injury ex-vivo. ITLD significantly increased the threshold for the opening of the mitochondrial permeability transition pore in response to calcium overload (nmol-calcium/mg-mitochondrial protein: 290±17 vs. 167±10 in CTRL, p<0.01) and significantly increased phosphorylation of STAT3 (1.8±0.08 vs. 1±0.16 in CTRL, p<0.05) and GSK-3ß (2.63±0.55 vs. 1±0.0.34 in CTRL, p<0.05). The ITLD-induced cardioprotection was fully abolished by Stattic, a specific inhibitor of STAT3. Transcriptome analysis revealed caveolin 2 (Cav2) was significantly upregulated by ITLD in hearts of LP rats under I/R injury. Co-immunoprecipitation experiments showed that Cav2 interacts with STAT3. CONCLUSIONS: ITLD protects the heart in late pregnancy against I/R injury by inhibiting the mPTP opening through Cav2/STAT3/GSK-3ß pathway.

Long-term treatment of ovariectomized mice with estradiol or phytoestrogens as a new model to study the role of estrogenic substances in the heart.

Epidemiological data reveal that the overall risk for heart disease is lower for premenopausal women compared to age-matched men. However, the beneficial effect for the female sex is lost upon menopause. Thus, it has been suggested that estrogens convey the protective effect for the female sex against heart disease. Numerous natural plant products, i.e., phytoestrogens (PE), interfere with or alter the development or function of the endocrine system. Although PEs have been studied intensively with regard to the effects on the reproductive organs, such as the uterus or mammary gland, surprisingly little data are available about the effects of PEs on the heart. Here, we conducted a long-term study with ovariectomized mice to examine putative estrogenic effects of the PEs genistein (GEN), resveratrol (RES), and equol (EQ), using estradiol (E2) as a reference compound on heart size, morphology, and cardiac gene expression. We report for the first time significant changes in these parameters by GEN and E2. Changes in the size of cardiomyocytes were observed by GEN and E2. In line with these observations, cardiac expression of insulin-like growth factor 1 ( IGF1) was significantly induced by both GEN and E2. Thus, we speculate that endocrine active compounds, like the isoflavone GEN, which is used as a food additive or as a drug for the treatment of menopausal symptoms, may directly affect heart function.