Human bone marrow stem cells co-cultured with neonatal rat cardiomyocytes display limited cardiomyogenic plasticity.

BACKGROUND AIMS: This study investigated whether neonatal rat cardiomyocytes (NRCM), when co-cultured, can induce transdifferentiation of either human mesenchymal stromal cells (MSC) or hematopoietic stem cells (HSC) into cardiomyocytes. Stem cells were obtained from patients with ischemic heart disease. METHODS: Ex vivo-expanded MSC or freshly isolated HSC were used to set-up a co-culture system between NRCM and MSC or HSC. 5-azacytidin (5-aza) or dimethylsulfoxide (DMSO) was used as differentiation-inducing factor. Co-cultured stem cells were separated from NRCM by flow sorting, and cardiac gene expression was analyzed by reverse transcriptase-polymerase chain reaction. Cellular morphology was analyzed by immunofluorescence and transmission electron microscopy (TEM). RESULTS: Co-culturing MSC induced expression of troponin T and GATA-4. However, no expression of alpha-actinin, myosin heavy chain or troponin I was detected. In the case of HSC, only expression of troponin T could be induced. Immunofluorescence and TEM confirmed the absence of sarcomeric organization in co-cultured MSC and HSC. Adding 5-aza or DMSO to the co-cultures did not influence differentiation. CONCLUSIONS: This in vitro co-culture study obtained no convincing evidence of transdifferentiation of either MSC or HSC into functional cardiomyocytes. Nevertheless, induction of troponin T was observed in MSC and HSC, and GATA-4 in MSC. However, no morphologic changes could be detected by immunofluorescence or by TEM. These data could explain why only limited functional improvement was reported in clinical stem cell trials.

Recovery of regional but not global contractile function by the direct intramyocardial autologous bone marrow transplantation: results from a randomized controlled clinical trial.

BACKGROUND: Recent trials have shown that intracoronary infusion of bone marrow cells (BMCs) improves functional recovery after acute myocardial infarction. However, whether this treatment is effective in heart failure as a consequence of remodeling after organized infarcts remains unclear. In this randomized trial, we assessed the hypothesis that direct intramyocardial injection of autologous mononuclear bone marrow cells during coronary artery bypass graft (CABG) could improve global and regional left ventricular ejection fraction (LVEF) at 4-month follow-up. METHODS AND RESULTS: Twenty patients (age 64.8+/-8.7; 17 male, 3 female) with a postinfarction nonviable scar, as assessed by thallium (Tl) scintigraphy and cardiac magnetic resonance imaging (MRI), scheduled for elective CABG, were included. They were randomized to a control group (n =10, CABG only) or a BMC group (CABG and injection of 60.10(6)+/-31.10(6) BMC). Primary end points were global LVEF change and wall thickening changes in the infarct area from baseline to 4-month follow-up, as measured by MRI. Changes in metabolic activity were measured by Tl scintigraphy and expressed as a score with a range from 0 to 4, corresponding to percent of maximal myocardial Tl uptake (4 indicates <50%, nonviable scar; 3, 50% to 60%; 2, 60% to 70%; 1, 70% to 80%; 0>80%). Global LVEF at baseline was 39.5+/-5.5% in controls and 42.9+/-10.3% in the BMC group (P=0.38). At 4 months, LVEF had increased to 43.1+/-10.9% in the control group and to 48.9+/-9.5% in the BMC group (P=0.23). Systolic thickening had improved from -0.6+/-1.3 mm at baseline to 1.8+/-2.6 mm at 4 months in the cell-implanted scars, whereas nontreated scars remained largely akinetic (-0.5+/-2.0 mm at baseline compared with 0.4+/-1.7 mm at 4 months, P=0.007 control versus BMC-treated group at 4 months). Defect score decreased from 4 to 3.3+/-0.9 in the BMC group and to 3.7+/-0.4 in the control group (P=0.18). CONCLUSIONS: At 4 months, there was no significant difference in global LVEF between both groups, but a recovery of regional contractile function in previously nonviable scar was observed in the BMC group.

Effect of prebiotic galacto-oligosaccharide, long-chain fructo-oligosaccharide infant formula on serum cholesterol and triacylglycerol levels.

OBJECTIVE: Cholesterol is a nutrient of essential importance in infant feeding because it is necessary in membrane development. In adults with high lipid levels, high doses of inulin (oligofructose) inconsistently decreased levels of serum cholesterol. The aim of the present study was to evaluate cholesterol and triacylglycerol levels in infants receiving a formula with a specific mixture of 0.6 g/100 mL of galacto-oligosaccharides (GOS) and long-chain fructo-oligosaccharides (lcFOS) in a ratio of 9/1, a control formula, or breast milk. Because the level of lcFOS in the infant milk is low, we hypothesized that there would be no differences between the formula groups. METHODS: Two hundred fifteen infants were included in a prospective, randomized, double-blinded, placebo-controlled trial during the first 6 mo of life. Formula-fed infants were randomized to receive a standard infant formula with a specific mixture of 0.6 g/100 mL of GOS/lcFOS, in a ratio of 9/1, or a control formula. Breast-fed infants were randomized to receive one of these two formulas after the mother had decided to discontinue breastfeeding. Serum levels of cholesterol, high-density lipoprotein, low-density lipoprotein (LDL), and triacylglycerol were determined at 8 and 26 wk of age and were provided for infants who received the GOS/lcFOS formula or control formula from birth or after cessation of breastfeeding and for the subgroups that were fully fed with breast milk and formula. RESULTS: One hundred eighty-seven infants completed the study. Total cholesterol and LDL levels at 8 and 26 wk were significantly lower in the formula-fed groups than in the breast-fed infants. There were no significant differences between the formula-fed groups. Levels of triacylglycerols and high-density lipoprotein did not differ between groups. CONCLUSION: Our study demonstrated no differences in total cholesterol and LDL cholesterol in infants receiving an infant formula with GOS/lcFOS from infants receiving a control infant formula. Furthermore, total cholesterol and LDL cholesterol levels were higher in breast-fed infants than in formula-fed infants.