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Aims Current efforts to treat myocardial infarction include the delivery of cells and matrix scaffolds. Bone marrow-derived mesenchymal stem cells (BM-MSCs) are multipotent stem cells that secrete angiogenic growth factors, and fibrin has been shown to be a biomaterial that provides structural support to cells and tissues. The objective of this study was to characterize the attachment and viability of BM-MSCs in fibrin in vitro, and then to assess the efficacy of treatment with BM-MSCs in fibrin for promoting neovascularization in the chronically infarcted myocardium. Materials & methods BM-MSCs were cultured in fibrin and assessed for cell attachment and viability by using immunofluorescence staining for actin filaments and Live/Dead® viability assays, respectively. To determine the efficacy of BM-MSCs in fibrin in vivo, chronically infarcted rat hearts were treated with either cells, cells in fibrin, fibrin or saline (n = 9). After 5 weeks, the infarct scar tissues were assessed for neovascularization. Results BM-MSCs exhibited robust cell attachment and viability when cultured in fibrin in vitro. Furthermore, when injected together into the infarcted tissue, BM-MSCs in fibrin could enhance neovasculature formation by increasing capillary density, in comparison to treatment by cells or fibrin separately. Concomitant to significant improvement in capillary density was an increase in the levels of VEGF in the infarct scar. Conclusion This study demonstrates the angiogenic potential of the combined delivery of BM-MSCs and fibrin, and highlights the advantage of stem cell-matrix approaches for myocardial repair.

Background Although the combination of doxorubicin (DOX) and trastuzumab (TRZ) reduces the progression and recurrence of breast cancer, these anticancer drugs are associated with significant cardiotoxic side effects. Objective We investigated whether prophylactic administration of flaxseed (FLX) and its bioactive components, α-linolenic acid (ALA) and secoisolariciresinol diglucoside (SDG), would be cardioprotective against DOX + TRZ–mediated cardiotoxicity in a chronic in vivo female murine model. Methods Wild-type C57BL/6 female mice (10–12 wk old) received daily prophylactic treatment with one of the following diets: 1) regular control (RC) semi-purified diet; 2) 10% FLX diet; 3) 4.4% ALA diet; or 4) 0.44% SDG diet for a total of 6 wks. Within each arm, mice received 3 weekly injections of 0.9% saline or a combination of DOX [8 mg/(kg.wk)] and TRZ [3 mg/(kg.wk)] starting at the end of week 3. The main outcome was to evaluate the effects of FLX, ALA, and SDG on cardiovascular remodeling and markers of apoptosis, inflammation, and mitochondrial dysfunction. Significance between measurements was determined using a 4 (diet) × 2 (chemotherapy) × 2 (time) mixed factorial design with repeated measures. Results In the RC + DOX + TRZ–treated mice at week 6 of the study, the left ventricular ejection fraction (LVEF) decreased by 50% compared with the baseline LVEF (P < 0.05). However, the prophylactic administration of the FLX, ALA, or SDG diet was partially cardioprotective, with mice in these treatment groups showing an ∼68% increase in LVEF compared with the RC + DOX + TRZ–treated group at week 6 (P < 0.05). Although markers of inflammation (nuclear transcription factor κB), apoptosis [poly (ADP-ribose) polymerase–1 and the ratio of BCL2-associated X protein to B-cell lymphoma–extra large], and mitochondrial dysfunction (BCL2-interacting protein 3) were significantly elevated by approximately 2-fold following treatment with RC + DOX + TRZ compared with treatment with RC + saline at week 6, prophylactic administration of FLX, ALA, or SDG partially downregulated these signaling pathways. Conclusion In a chronic in vivo female C57BL/6 mouse model of DOX + TRZ–mediated cardiotoxicity, FLX, ALA, and SDG were partially cardioprotective.

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Background The gut-derived hormone ghrelin, especially its acylated form, plays a major role in the regulation of systemic metabolism and exerts also relevant cardioprotective effects, hence it has been proposed for the treatment of heart failure (HF). We tested the hypothesis that ghrelin can directly modulate cardiac energy substrate metabolism. Methods and Results We used chronically instrumented dogs, 8 with pacing-induced HF and 6 normal controls. 1.2 nmol/kg/hour of human des-acyl ghrelin was infused intravenously for 15 min, followed by washout (re-baseline) and infusion of acyl ghrelin at the same dose. 3H-oleate and 14C-glucose were co-infused and arterial and coronary sinus blood sampled to measure cardiac free fatty acids (FFA) and glucose oxidation and lactate uptake. As expected, cardiac substrate metabolism was profoundly altered in HF, since baseline FFA and glucose oxidation were, respectively, >70% lower and >160% higher compared to control. Neither des-acyl ghrelin nor acyl ghrelin affected significantly function and metabolism in normal hearts. However, in HF, des-acyl and acyl ghrelin enhanced MVO2 by 10.2±3.5 and 9.9±3.7%, respectively, (P<0.05), while cardiac mechanical efficiency was not significantly altered. This was associated, respectively, with a 41.3±6.7 and 32.5±10.9% increase in FFA oxidation and a 31.3±9.2 and 41.4±8.9% decrease in glucose oxidation (all P<0.05). Conclusions Acute increases in des-acyl ghrelin or acyl ghrelin do not interfere with cardiac metabolism in normal, while they enhance FFA oxidation and reduce glucose oxidation in HF, thus partially correcting its metabolic alterations. This novel mechanism might contribute to the cardioprotective effects of ghrelin in HF.