Significant morbidity and mortality among patients with diabetes mellitus result largely from a greatly increased incidence of microvascular complications. Proliferative diabetic retinopathy (PDR) and end stage renal disease (ESRD) are two of the most common and severe microvascular complications of diabetes. A high concordance exists in the development of PDR and ESRD in diabetic patients, as well as strong familial aggregation of these complications, suggesting a common underlying genetic mechanism. However, the precise gene(s) and genetic variant(s) involved remain largely unknown. Erythropoietin (EPO) is a potent angiogenic factor observed in the diabetic human and mouse eye. By a combination of case-control association and functional studies, we demonstrate that the T allele of SNP rs1617640 in the promoter of the EPO gene is significantly associated with PDR and ESRD in three European-American cohorts [Utah: P ؍ 1.91 ؋ 10 ؊3 ; Genetics of Kidneys in Diabetes (GoKinD) Study: P ؍ 2.66 ؋ 10 ؊8 ; and Boston: P ؍ 2.1 ؋ 10 ؊2 ]. The EPO concentration in human vitreous body was 7.5-fold higher in normal subjects with the TT risk genotype than in those with the GG genotype. Computational analysis suggests that the risk allele (T) of rs1617640 creates a matrix match with the EVI1/MEL1 or AP1 binding site, accounting for an observed 25-fold enhancement of luciferase reporter expression as compared with the G allele. These results suggest that rs1617640 in the EPO promoter is significantly associated with PDR and ESRD. This study identifies a disease risk-associated gene and potential pathway mediating severe diabetic microvascular complications. diabetic microvascular complication ͉ end stage renal disease ͉ proliferative diabetic retinopathy ͉ SNP ͉ association
We report intrauterine growth restriction (IUGR) increases vascular stiffening in both male and female rats through increased collagen content and altered elastin structure more than a high-fat diet (HFD) alone. Our study shows the importance of stiffness supporting the hypothesis that there are physiologic differences and potential windows for early intervention targeting vascular remodeling mechanisms.
Intrauterine growth restriction (IUGR) and maternal consumption of a high‐saturated‐fat diet (HFD) increase the risk of hypercholesterolemia, a leading cause of morbidity and mortality. Many pregnant women eat a HFD, thus exposing the fetus to a HFD in utero. The cumulative effect of in utero exposure to IUGR and a HFD on offspring cholesterol levels remains unknown. Furthermore, little is known about the mechanism through which IUGR and maternal HFD consumption increase cholesterol. We hypothesize that IUGR combined with a maternal HFD would increase offspring serum and hepatic cholesterol accumulation via alteration in levels of key proteins involved in cholesterol metabolism. To test our hypothesis we used a rat model of surgically induced IUGR and fed the dams a regular diet or a HFD. HFD‐fed dams consumed the same kilocalories as regular diet‐fed dams, with no difference between surgical intervention groups. In the offspring, IUGR combined with a maternal HFD increased hepatic cholesterol levels, low‐density lipoprotein (LDL) receptor protein levels, and Ldlr activity in female rat offspring at birth and both sexes at postnatal day 14 relative to non‐IUGR offspring both from regular diet‐ and HFD‐fed dams. These findings suggest that IUGR combined with a maternal HFD increases hepatic cholesterol accumulation via increased LDL cholesterol uptake into the liver with resulting persistent increases in hepatic cholesterol accumulation.
Background: Intrauterine growth restriction (IUGR) increases the risk of adult-onset hypercholesterolemia. High-fat diet (HFD) consumption potentiates IUGR-induced increased cholesterol. Cholesterol is converted to bile acids by Cyp7a1 in preparation for excretion. We hypothesized that IUGR rats fed a HFD will have increased cholesterol, decreased Cyp7a1 protein levels, and decreased bile acids compared to control rats fed a HFD. Methods: At day 21, IUGR and control pups were placed on one of three diets: a regular chow or one of two HFDs containing 1% or 2% cholesterol. Cholesterol levels and hepatic Cyp7a1 protein levels were quantified a postnatal week 28. results: Both HFDs increased serum cholesterol levels in control rats, and HFD fed IUGR rats had further increased serum cholesterol up to 35-fold. Both HFDs increased hepatic cholesterol levels, and IUGR further increased hepatic cholesterol levels up to fivefold. IUGR decreased hepatic Cyp7a1 protein up to 75%, and hepatic bile acids up to 54%. conclusion: IUGR increased cholesterol and bile acids and decreased Cyp7a1 protein in rats fed a HFD without changing food intake. These findings suggest that IUGR increases the vulnerability of HFD fed rats to hypercholesterolemia via decreased cholesterol conversion to bile acids. i ntrauterine growth restriction (IUGR) predisposes to adultonset hypercholesterolemia (1,2). Epidemiologic studies demonstrate that late-gestation exposure to famine makes individuals more susceptible to hypercholesterolemia only when combined with postnatal consumption of a high-fat diet (HFD) (3). These results suggest that the postnatal nutritional environment impacts cholesterol metabolism differently in IUGR individuals compared their normally grown peers. A better understanding of the mechanism through which IUGR combined with a postnatal HFD impacts cholesterol metabolism would provide a foundation to pursue further research into preventing hypercholesterolemia in IUGR individuals.While the effects of HFD consumption in individuals born IUGR are not well understood, the detrimental effects of HFD consumption in the general population has been extensively documented. HFD consumption often leads to hypercholesterolemia and eventually cardiovascular disease (4). Higher cholesterol levels increase the risk of cardiovascular disease in a continuous, graded fashion (5,6). IUGR may potentiate hypercholesterolemia in individuals that consume a HFD and thus increase morbidity and mortality in this population. The impact of IUGR on cholesterol levels in humans is more evident in the recent decades due to the changing Western diet (7). Average daily fat and cholesterol intake in the United States is ~23-33 g of saturated fat and up to 400 mg cholesterol, both well above the recommended daily intake of ~16 g or no more than 7% of caloric intake for saturated fat and 200 mg cholesterol (7).The liver is the primary organ for regulating both serum and hepatic cholesterol levels. Cholesterol homeostasis is regulated by a series of hepatic genes...
Intrauterine growth restriction (IUGR) programs neurodevelopmental impairment and long-term neurological morbidities. Neurological morbidities in IUGR infants are correlated with changes hippocampal volume. We previously demonstrated that IUGR alters hippocampal cellular composition in both neonatal and juvenile rat pups in association with altered hippocampal gene expression and epigenetic determinants. PPARγ signaling is important for neurodevelopment as well as epigenetic integrity in the brain via the PPARγ-Setd8-H4K20me1 axis and Wnt signaling. We hypothesized that IUGR would decrease expression of PPARγ, Setd8, and H4K20me1 in juvenile rat hippocampus. We further hypothesized that reduced PPARγ-Setd8-H4K20me1 would be associated with reduced Wnt signaling genes Wnt3a and β-catenin, and wnt target gene Axin2. To test our hypothesis we used a rat model of uteroplacental insufficiency-induced IUGR. We demonstrated that PPARγ localizes to oligodendrocytes, neurons and astrocytes within the juvenile rat hippocampus. We also demonstrated that IUGR reduces levels of PPARγ, Setd8 and H4K20me1 in male and female juvenile rat hippocampus in conjunction with reduced Wnt signaling components in only male rats. We speculate that reduced PPARγ and Wnt signaling may contribute to altered hippocampal cellular composition which, in turn, may contribute to impaired neurodevelopment and subsequent neurocognitive impairment in IUGR offspring.
Exfoliation glaucoma (XFG) is the commonest identifiablecause of secondary open-angle glaucoma worldwide, characterized by the deposition of fibrillar proteins in the anterior segment of the eye. We investigated LOXL1 gene variants previously identified to confer susceptibility to XFG in a Utah Caucasian cohort. After a standard eye examination protocol we genotyped SNPs rs2165241 and rs3825942 in 62 XFG or exfoliation syndrome (XFS) patients and 170 normal controls. Genotype frequency distribution, odds ratios (ORs) and population attributable risks were calculated for the risk alleles. The SNP rs2165241 was significantly associated with XFG and XFS (p = 4.13 x 10 -9 for an additive model, OR het = 4.42 (2.30 -8.50), OR hom = 34.19 (4.48 -261.00); T allele: 83.1% in cases versus 52.4% in controls). Significant association was also found for rs3825942: (p = 1.89 x 10 -6 ). Our findings confirm genetic association of LOXL1 with XFG and XFS and implicate a potential role of cross linking of elastin in the pathogenesis of XFG. This information will potentially guide glaucoma monitoring efforts by targeting individuals whose genetic profiles put them at higher risk for XFG.
To address the hypothesis that maternal uteroplacental insufficiency (UPI) increases severity of retinopathy of prematurity, we developed a composite rat model of UPI and oxygen-fluctuations and removed premature birth as a confounding factor. Timed-pregnant Sprague-Dawley dams underwent bilateral uterine artery ligation or anesthesia (control) at e19.5. Full-term pups developed in room air (RA) or an oxygen-induced retinopathy (OIR) model. Isolectin-stained retinal flat-mounts were analyzed for percent of areas of avascular/total retina (AVA) and of intravitreal neovascular/total retina (IVNV). Pup weights and serum and mRNA of liver and kidney VEGF, IGF-1, and erythropoietin (EPO) were determined. Multivariable mixed effects linear regressions and Pearson correlations were performed using STATA14. Postnatal growth restriction occurred in pups in UPI/RA, but not in UPI/OIR. Weight gain was similar between UPI/OIR and control/OIR pups. AVA was reduced and a trend toward reduced IVNV was seen in UPI/OIR compared to control/OIR. No difference in birth weights of UPI/OIR vs. control/OIR pups occurred. Serum and renal IGF-1 and EPO were significantly increased in UPI/OIR compared to control/OIR pups. In the absence of prematurity, UPI increased angiogenic factors in association with reduced OIR severity, suggesting that ischemia from UPI could yield protective angiogenic effects by offspring.
Background: Intrauterine growth restriction (IUGR) offspring with rapid catch-up growth are at increased risk for early obesity especially in males. Persistent insulin-like growth factor-1 (IGF-1) reduction is an important risk factor. Using a mouse model of maternal hypertension-induced IUGR, we examined IGF-1 levels, promoter DNA methylation, and histone H3 covalent modifications at birth (D1). We additionally investigated whether prenatal perturbations could reset at preadolescence (D21). Methods: IUGR was induced via maternal thromboxane A 2 -analog infusion in mice. results: IUGR uniformly decreased D1 IGF-1 mRNA and protein levels with reduced promoter 1 (P1) transcription and increased P1 DNA methylation. IUGR males also had increased H3K4ac at exon 5 and 3′ distal UTR. At D21, IUGR males continued to have decreased IGF-1 levels, originating from both P1 and P2 with reduced 1A variant. IUGR males also had decreased activation mark of H3K4me3 at P1 compared with sham males. In contrast, D21 IUGR females normalized their IGF-1 levels, in association with an increased activation mark of H3K4me3 at P1 compared with sham females. conclusion: IUGR uniformly affected D1 hepatic IGF-1 epigenetic modifications in both sexes. However, at preadolescence, IUGR males are unable to correct for the prenatal reduction possibly due to a more perturbed IGF-1 chromatin structure.i ntrauterine growth restriction (IUGR) predisposes offspring toward early-onset metabolic syndrome. This predisposition is particularly pertinent with rapid postnatal catch-up growth and affects males more than females (1). The molecular mechanisms underlying this sex-specific predisposition remain elusive. Insulin-like growth factor 1 (IGF-1), a major regulator of growth and metabolism, has generated significant interest in the field (2). IGF-1 disruption has been implicated in aberrant growth and development of metabolic syndrome in both IUGR humans and animal models (3-6). In particular, decreased IGF-1 have been observed in IUGR humans who ultimately develop metabolic syndrome as adults (7,8).The IGF-1 gene is an ideal candidate to examine IUGR's effects not only because of its growth and metabolic properties but because of its complex gene structure allowing for developmental-and tissue-specific expression. The majority of serum IGF-1 is synthesized from the liver (9). The IGF-1 gene is regulated by two alternative promoters, promoter P1 initiates transcription from exon 1 while promoter P2 from exon 2. P1 is active in fetal life, whereas P2 becomes upregulated at ~3 wk of life when growth hormone exerts its effects on the rodent IGF-1 gene (10). The rodent IGF-1 gene also has an alternatively spliced exon, with the A variant excluding exon 5 and the B variant includes exon 5. Both alternative promoter selection and alternative exon splicing require specific epigenetic modifications to direct transcriptional machinery for specific mRNA transcript generation (11,12).Given that prenatal insults are known to affect gene-specific DNA methylation a...
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