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The incidence of obesity and overweight has reached epidemic levels in the United States and developed countries worldwide. Even more alarming is the increasing prevalence of metabolic diseases in younger children and adolescents. Infants born to obese, overweight, and diabetic mothers (even when normal weight) have increased adiposity and are at increased risk of later metabolic disease. In addition to maternal glucose, hyperlipidemia and inflammation may contribute to the childhood obesity epidemic through fetal metabolic programming, the mechanisms of which are not well understood. Pregravid obesity, when combined with normal changes in maternal metabolism, may magnify increases in inflammation and blood lipids, which can have profound effects on the developing embryo and the fetus in utero. Fetal exposure to excess blood lipids, particularly saturated fatty acids, can activate proinflammatory pathways, which could impact substrate metabolism and mitochondrial function, as well as stem cell fate, all of which affect organ development and the response to the postnatal environment. Fetal and neonatal life are characterized by tremendous plasticity and the ability to respond to environmental factors (nutrients, oxygen, hormones) by altering gene expression levels via epigenetic modifications. Given that lipids act as both transcriptional activators and signaling molecules, excess fetal lipid exposure may regulate genes involved in lipid sensing and metabolism through epigenetic mechanisms. Epigenetic regulation of gene expression is characterized by covalent modifications to DNA and chromatin that alter gene expression independent of gene sequence. Epigenetic modifications can be maintained through positive and negative feedback loops, thereby creating stable changes in the expression of metabolic genes and their main transcriptional regulators. The purpose of this article is to review current literature on maternal-fetal lipid metabolism and maternal obesity outcomes and to suggest some potential mechanisms for fetal metabolic programming in key organ systems that regulate postnatal energy balance, with an emphasis on epigenetics and the intrauterine environment. nutrition; pregnancy; epigenetics; inflammation; diabetes: lipids doi: 10.1152/ajpregu.00310.2010.

Objective: Diet therapy in gestational diabetes mellitus (GDM) has focused on carbohydrate restriction but is poorly substantiated. In this pilot randomized clinical trial, we challenged the conventional low-carbohydrate/higher-fat (LC/CONV) diet, hypothesizing that a higher-complex carbohydrate/lower-fat (CHOICE) diet would improve maternal insulin resistance (IR), adipose tissue (AT) lipolysis, and infant adiposity.Research Design and Methods: At 31 weeks, 12 diet-controlled overweight/obese women with GDM were randomized to an isocaloric LC/CONV (40% carbohydrate/45% fat/15% protein; n = 6) or CHOICE (60%/25%/15%; n = 6) diet. All meals were provided. AT was biopsied at 37 weeks.Results: After ∼7 weeks, fasting glucose (P = 0.03) and free fatty acids (P = 0.06) decreased on CHOICE, whereas fasting glucose increased on LC/CONV (P = 0.03). Insulin suppression of AT lipolysis was improved on CHOICE versus LC/CONV (56 vs. 31%, P = 0.005), consistent with improved IR. AT expression of multiple proinflammatory genes was lower on CHOICE (P < 0.01). Infant adiposity trended lower with CHOICE (10.1 ± 1.4 vs. 12.6 ± 2%, respectively).Conclusions: A CHOICE diet may improve maternal IR and infant adiposity, challenging recommendations for a LC/CONV diet. [ABSTRACT FROM AUTHOR]

The search for the ideal vector for stem cell gene therapy continues as recognized problems remain with all existing viral vectors. The recent identification of over 100 new serotypes of AAV significantly expands the repertoire of available gene transfer vectors. Additionally, the capacity to pseudotype rAAV2 genomes in novel capsids facilitates evaluation. We and others have analyzed rAAV2-mediated gene transfer into hematopoietic stem cells (HSC). However, despite efficient gene-marking of primitive HSCs, there are identified limitations to transgene expression especially at early time points. The use of novel capsids has been shown to overcome these limitations in other tissues and expand the host range of AAV. We tested transduction of CD34+ cells from cytokine-primed peripheral blood, CD34+CD38− cells from cord blood (CB) and the CD34+CD38- cell line TF1a with AAV2-dsRed pseudotyped in capsids of AAV1, 2, 5, 7, 8 and 9. Transduced cells were analyzed by flow cytometry 24 and 48 hours post transduction. Results revealed that the highest level of transgene expression was observed with AAV7 in HSCs from all sources while AAV 2 and 9 showed the lowest. The hierarchy of transgene expression in vitro was: AAV7>AAV8≥AAV1>AAV5>AAV2=AAV9 regardless of the source of CD34+cells. These results indicate that the use of certain novel capsids allows circumvention of limitations to expression from AAV2. We next evaluated in vivo engraftment of human HSCs transduced with pseudotyped rAAV in a NOD/SCID xenotransplant model. Transduced CD34+ cells purified from either CB or cytokine primed peripheral blood were transplanted into sublethally irradiated mice. The pseudotyped rAAV2 genome encoded the firefly luciferase gene under the control of the CBA promoter. Serial live imaging of recipients revealed transgene expression from each of the 6 serotypes tested. However the levels and trends for long term expression variedby serotype. At early time points, the highest initial expression was observed with AAV9 followed by AAV7 and 8. AAV2 showed the lowest level of initial expression. However differences emerged over time. AAV7, 9 and 8 capsids emerged as the best serotypes for long-term expression in vivo, followed by AAV2. AAV5 and 1 showed a rapid decline in expression after initial moderately high levels of expression. These differences suggest that the processing of pseudotyped rAAV in vivo varies with the capsid. AAV serotypes also appear to have different transduction properties in vivo as compared with in vitro. The mechanisms underlying these differences are being investigated. The rapid and robust expression seen in vivo with certain serotypes is highly promising and underscores the need for further evaluation of pseudotyped rAAV for stem cell gene transfer.Molecular Therapy (2006) 13, S188–S188; doi: 10.1016/j.ymthe.2006.08.555 [ABSTRACT FROM AUTHOR]