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Long Lasting Microvascular Tone Alteration in Rat Offspring Exposed In Utero to Maternal Hyperglycaemia.

ABSTRACT: Epidemiologic studies have demonstrated that cardiovascular risk is not only determined by conventional risk factors in adulthood, but also by early life events which may reprogram vascular function. To evaluate the effect of maternal diabetes on fetal programming of vascular tone in offspring and its evolution during adulthood, we investigated vascular reactivity of third order mesenteric arteries from diabetic mother offspring (DMO) and control mother offspring (CMO) aged 3 and 18 months. In arteries isolated from DMO the relaxation induced by prostacyclin analogues was reduced in both 3- and 18-month old animals although endothelium (acetylcholine)-mediated relaxation was reduced in 18-month old DMO only. Endothelium-independent (sodium nitroprusside) relaxation was not affected. Pressure-induced myogenic tone, which controls local blood flow, was reduced in 18-month old CMO compared to 3-month old CMO. Interestingly, myogenic tone was maintained at a high level in 18-month old DMO even though agonist-induced vasoconstriction was not altered. These perturbations, in 18-months old DMO rats, were associated with an increased pMLC/MLC, pPKA/PKA ratio and an activated RhoA protein. Thus, we highlighted perturbations in the reactivity of resistance mesenteric arteries in DMO, at as early as 3 months of age, followed by the maintenance of high myogenic tone in older rats. These modifications are in favour of excessive vasoconstrictor tone. These results evidenced a fetal programming of vascular functions of resistance arteries in adult rats exposed in utero to maternal diabetes, which could explain a re-setting of vascular functions and, at least in part, the occurrence of hypertension later in life.

SUBMITTER: Vessieres E

PROVIDER: S-EPMC4710502 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Long Lasting Microvascular Tone Alteration in Rat Offspring Exposed In Utero to Maternal Hyperglycaemia.

Vessières Emilie E Dib Abdallah A Bourreau Jennifer J Lelièvre Eric E Custaud Marc-Antoine MA Lelièvre-Pégorier Martine M Loufrani Laurent L Henrion Daniel D Fassot Céline C

PloS one 20160112 1

Epidemiologic studies have demonstrated that cardiovascular risk is not only determined by conventional risk factors in adulthood, but also by early life events which may reprogram vascular function. To evaluate the effect of maternal diabetes on fetal programming of vascular tone in offspring and its evolution during adulthood, we investigated vascular reactivity of third order mesenteric arteries from diabetic mother offspring (DMO) and control mother offspring (CMO) aged 3 and 18 months. In a ...[more]

PMID: 26756337

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Project description:AIMS/HYPOTHESIS:Individuals exposed to maternal diabetes in utero are more likely to develop metabolic and cardiovascular diseases later in life. This may be partially attributable to epigenetic regulation of gene expression. We performed an epigenome-wide association study to examine whether differential DNA methylation, a major source of epigenetic regulation, can be observed in offspring of mothers with type 2 diabetes during the pregnancy (OMD) compared with offspring of mothers with no diabetes during the pregnancy (OMND). METHODS:DNA methylation was measured in peripheral blood using the Illumina HumanMethylation450K BeadChip. A total of 423,311 CpG sites were analysed in 388 Pima Indian individuals, mean age at examination was 13.0 years, 187 of whom were OMD and 201 were OMND. Differences in methylation between OMD and OMND were assessed. RESULTS:Forty-eight differentially methylated CpG sites (with an empirical false discovery rate ?0.05), mapping to 29 genes and ten intergenic regions, were identified. The gene with the strongest evidence was LHX3, in which six CpG sites were hypermethylated in OMD compared with OMND (p???1.1?×?10-5). Similarly, a CpG near PRDM16 was hypermethylated in OMD (1.1% higher, p?=?5.6?×?10-7), where hypermethylation also predicted future diabetes risk (HR 2.12 per SD methylation increase, p?=?9.7?×?10-5). Hypermethylation near AK3 and hypomethylation at PCDHGA4 and STC1 were associated with exposure to diabetes in utero (AK3: 2.5% higher, p?=?7.8?×?10-6; PCDHGA4: 2.8% lower, p?=?3.0?×?10-5; STC1: 2.9% lower, p?=?1.6?×?10-5) and decreased insulin secretory function among offspring with normal glucose tolerance (AK3: 0.088 SD lower per SD of methylation increase, p?=?0.02; PCDHGA4: 0.08 lower SD per SD of methylation decrease, p?=?0.03; STC1: 0.072 SD lower per SD of methylation decrease, p?=?0.05). Seventeen CpG sites were also associated with BMI (p???0.05). Pathway analysis of the genes with at least one differentially methylated CpG (p?<?0.005) showed enrichment for three relevant biological pathways. CONCLUSIONS/INTERPRETATION:Intrauterine exposure to diabetes can affect methylation at multiple genomic sites. Methylation status at some of these sites can impair insulin secretion, increase body weight and increase risk of type 2 diabetes.

Project description:The risk of obesity in adulthood is subject to programming beginning at conception. In animal models, exposure to maternal obesity and high fat diets influences the risk of obesity in the offspring. Among other long-term changes, offspring from obese rats develop hyperinsulinemia, hepatic steatosis, and lipogenic gene expression in the liver at weaning. However, the precise underlying mechanisms leading to metabolic dysregulation in the offspring remains unclear. Using a rat model of overfeeding-induced obesity, we previously demonstrated that exposure to maternal obesity from pre-conception to birth, is sufficient to program increased obesity risk in the offspring. Offspring of obese rat dams gain greater body weight and fat mass when fed high fat diet (HFD) as compared to lean dam. Since, disruptions of diurnal circadian rhythm are known to detrimentally impact metabolically active tissues such as liver, we examined the hypothesis that maternal obesity leads to perturbations of core clock components and thus energy metabolism in offspring liver. Offspring from lean and obese dams were examined at post-natal day 35, following a short (2 wk) HFD challenge. Hepatic mRNA expression of circadian (CLOCK, BMAL1, REV-ERB?, CRY, PER) and metabolic (PPAR?, SIRT1) genes were strongly suppressed in offspring exposed to both maternal obesity and HFD. Using a mathematical model, we identified two distinct biological mechanisms that modulate PPAR? mRNA expression: i) decreased mRNA synthesis rates; and ii) increased non-specific mRNA degradation rate. Moreover, our findings demonstrate that changes in PPAR? transcription were associated with epigenomic alterations in H3K4me3 and H3K27me3 histone marks near the PPAR? transcription start site. Our findings indicated that offspring from obese rat dams have detrimental alternations to circadian machinery that may contribute to impaired liver metabolism in response to HFD, specifically via reduced PPAR? expression prior to obesity development.

Project description:Aim/hypothesis:In utero exposure to maternal diabetes increases the risk of developing hypertension and cardiovascular disorders during adulthood. We have previously shown that this is associated with changes in vascular tone in favor of a vasoconstrictor profile, which is involved in the development of hypertension. This excessive constrictor tone has also a strong impact on vascular structure. Our objective was to study the impact of in utero exposure to maternal diabetes on vascular structure and remodeling induced by chronic changes in hemodynamic parameters. Methods and Results: We used an animal model of rats exposed in utero to maternal hyperglycemia (DMO), which developed hypertension at 6 months of age. At a pre-hypertensive stage (3 months of age), we observed deep structural modifications of the vascular wall without any hemodynamic perturbations. Indeed, in basal conditions, resistance arteries of DMO rats are smaller than those of control mother offspring (CMO) rats; in addition, large arteries like thoracic aorta of DMO rats have an increase of smooth muscle cell attachments to elastic lamellae. In an isolated perfused kidney, we also observed a leftward shift of the flow/pressure relationship, suggesting a rise in renal peripheral vascular resistance in DMO compared to CMO rats. In this context, we studied vascular remodeling in response to reduced blood flow by in vivo mesenteric arteries ligation. In DMO rats, inward remodeling induced by a chronic reduction in blood flow (1 or 3 weeks after ligation) did not occur by contrast to CMO rats in which arterial diameter decreased from 428 ± 17 ?m to 331 ± 20 ?m (at 125 mmHg, p = 0.001). In these animals, the transglutaminase 2 (TG2) pathway, essential for inward remodeling development in case of flow perturbations, was not activated in low-flow (LF) mesenteric arteries. Finally, in old hypertensive DMO rats (18 months of age), we were not able to detect a pressure-induced remodeling in thoracic aorta. Conclusions: Our results demonstrate for the first time that in utero exposure to maternal diabetes induces deep changes in the vascular structure. Indeed, the early narrowing of the microvasculature and the structural modifications of conductance arteries could be a pre-emptive adaptation to fetal programming of hypertension.

Dataset Information

Long Lasting Microvascular Tone Alteration in Rat Offspring Exposed In Utero to Maternal Hyperglycaemia.

Publications

Long Lasting Microvascular Tone Alteration in Rat Offspring Exposed In Utero to Maternal Hyperglycaemia.

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