Maternal arachidonic acid supplementation improves neurodevelopment of offspring from healthy and diabetic rats

Effects of Maternal Diabetes and Diet on Gene Expression in the Murine Placenta

Adverse exposures during pregnancy have been shown to contribute to susceptibility for chronic diseases in offspring. Maternal diabetes during pregnancy is associated with higher risk of pregnancy complications, structural birth defects, and cardiometabolic health impairments later in life. We showed previously in a mouse model that the placenta is smaller in diabetic pregnancies, with reduced size of the junctional zone and labyrinth. In addition, cell migration is impaired, resulting in ectopic accumulation of spongiotrophoblasts within the labyrinth. The present study had the goal to identify the mechanisms underlying the growth defects and trophoblast migration abnormalities. Based upon gene expression assays of 47 candidate genes, we were able to attribute the reduced growth of diabetic placenta to alterations in the Insulin growth factor and Serotonin signaling pathways, and provide evidence for Prostaglandin signaling deficiencies as the possible cause for abnormal trophoblast migration. Furthermore, our results reinforce the notion that the exposure to maternal diabetes has particularly pronounced effects on gene expression at midgestation time points. An implication of these findings is that mechanisms underlying developmental programming act early in pregnancy, during placenta morphogenesis, and before the conceptus switches from histiotrophic to hemotrophic nutrition.

Expression Pattern of ALOXE3 in Mouse Brain Suggests Its Relationship with Seizure Susceptibility

Arachidonic acid (AA), a polyunsaturated fatty acid, is involved in the modulation of neuronal excitability in the brain. Arachidonate lipoxygenase 3 (ALOXE3), a critical enzyme in the AA metabolic pathway, catalyzes the derivate of AA into hepoxilins. However, the expression pattern of ALOXE3 and its role in the brain has not been described until now. Here we showed that the levels of Aloxe3 mRNA and protein kept increasing since birth and reached the highest level at postnatal day 30 in the mouse hippocampus and temporal cortex. Histomorphological analyses indicated that ALOXE3 was enriched in adult hippocampus, somatosensory cortex and striatum. The distribution was restricted to the neurites of function-specific subregions, such as mossy fibre connecting hilus and CA3 neurons, termini of Schaffer collateral projections, and the layers III and IV of somatosensory cortex. The spatiotemporal expression pattern of ALOXE3 suggests its potential role in the modulation of neural excitability and seizure susceptibility. In fact, decreased expression of ALOXE3 and elevated concentration of AA in the hippocampus was found after status epilepticus (SE) induced by pilocarpine. Local overexpression of ALOXE3 via adeno-associated virus gene transfer restored the elevated AA level induced by SE, alleviated seizure severities by increasing the latencies to myclonic switch, clonic convulsions and tonic hindlimb extensions, and decreased the mortality rate in the pilocarpine-induced SE model. These results suggest that the expression of ALOXE3 is a crucial regulator of AA metabolism in brain, and potentially acts as a regulator of neural excitability, thereby controlling brain development and seizure susceptibility.

Significance of Increasing n-3 PUFA Content in Pork on Human Health

Evidence for the health-promoting effects of food rich in n-3 polyunsaturated fatty acids (n-3 PUFA) is reviewed. Pork is an important meat source for humans. According to a report by the US Department of Agriculture ( http://www.ers.usda.gov/topics ), the pork consumption worldwide in 2011 was about 79.3 million tons, much higher than that of beef (48.2 million tons). Pork also contains high levels of unsaturated fatty acids relative to ruminant meats (Enser, M., Hallett, K., Hewett, B., Fursey, G. A. J. and Wood, J. D. (1996) . Fatty acid content and composition of English beef, lamb, and pork at retail. Meat Sci. 44:443-458). The available literature indicates that the levels of eicosatetraenoic and docosahexaenoic in pork may be increased by fish-derived or linseed products, the extent of which being dependent on the nature of the supplementation. Transgenic pigs and plants show promise with high content of n-3 PUFA and low ratio of n-6/n-3 fatty acids in their tissues. The approaches mentioned for decreasing n-6/n-3 ratios have both advantages and disadvantages. Selected articles are critically reviewed and summarized.

Maternal obesity reduces milk lipid production in lactating mice by inhibiting acetyl-CoA carboxylase and impairing fatty acid synthesis

Maternal metabolic and nutrient trafficking adaptations to lactation differ among lean and obese mice fed a high fat (HF) diet. Obesity is thought to impair milk lipid production, in part, by decreasing trafficking of dietary and de novo synthesized lipids to the mammary gland. Here, we report that de novo lipogenesis regulatory mechanisms are disrupted in mammary glands of lactating HF-fed obese (HF-Ob) mice. HF feeding decreased the total levels of acetyl-CoA carboxylase-1 (ACC), and this effect was exacerbated in obese mice. The relative levels of phosphorylated (inactive) ACC, were elevated in the epithelium, and decreased in the adipose stroma, of mammary tissue from HF-Ob mice compared to those of HF-fed lean (HF-Ln) mice. Mammary gland levels of AMP-activated protein kinase (AMPK), which catalyzes formation of inactive ACC, were also selectively elevated in mammary glands of HF-Ob relative to HF-Ln dams or to low fat fed dams. These responses correlated with evidence of increased lipid retention in mammary adipose, and decreased lipid levels in mammary epithelial cells, of HF-Ob dams. Collectively, our data suggests that maternal obesity impairs milk lipid production, in part, by disrupting the balance of de novo lipid synthesis in the epithelial and adipose stromal compartments of mammary tissue through processes that appear to be related to increased mammary gland AMPK activity, ACC inhibition, and decreased fatty acid synthesis.

LPIAT1 regulates arachidonic acid content in phosphatidylinositol and is required for cortical lamination in mice

Arachidonic acid (AA) is remarkably enriched in phosphatidylinositol (PI). Studies using knockout mice of lysophosphatidylinositol acyltransferase 1, which selectively incorporates AA into PI, reveal that AA-containing PI plays a crucial role in cortical lamination and neuronal migration during brain development.

Dietary arachidonic acid (AA) has roles in growth, neuronal development, and cognitive function in infants. AA is remarkably enriched in phosphatidylinositol (PI), an important constituent of biological membranes in mammals; however, the physiological significance of AA-containing PI remains unknown. In an RNA interference–based genetic screen using Caenorhabditis elegans, we recently cloned mboa-7 as an acyltransferase that selectively incorporates AA into PI. Here we show that lysophosphatidylinositol acyltransferase 1 (LPIAT1, also known as MBOAT7), the closest mammalian homologue, plays a crucial role in brain development in mice. Lpiat1^−/− mice show almost no LPIAT activity with arachidonoyl-CoA as an acyl donor and show reduced AA contents in PI and PI phosphates. Lpiat1^−/− mice die within a month and show atrophy of the cerebral cortex and hippocampus. Immunohistochemical analysis reveals disordered cortical lamination and delayed neuronal migration in the cortex of E18.5 Lpiat1^−/− mice. LPIAT1 deficiency also causes disordered neuronal processes in the cortex and reduced neurite outgrowth in vitro. Taken together, these results demonstrate that AA-containing PI/PI phosphates play an important role in normal cortical lamination during brain development in mice.

Maternal serum docosahexaenoic acid and schizophrenia spectrum disorders in adult offspring

It is believed that during mid-to-late gestation, docosahexaenoic acid (DHA), an n-3 fatty acid, plays an important role in fetal and infant brain development, including neurocognitive and neuromotor functions. Deficits in several such functions have been associated with schizophrenia. Though sufficient levels of DHA appear to be important in neurodevelopment, elevated maternal DHA levels have also been associated with abnormal reproductive outcomes in both animal models and humans. Our objective was to assess whether a disturbance in maternal DHA levels, measured prospectively during pregnancy, was associated with risk of schizophrenia and other schizophrenia spectrum disorders (SSD) in adult offspring. In order to test the hypothesis that abnormal levels of DHA are associated with SSD, a case-control study nested within a large, population-based birth cohort, born from 1959 through 1967 and followed up for SSD from 1981 through 1997, was utilized. Maternal levels of both DHA and arachidonic acid (AA), an n-6 fatty acid, were analyzed in archived maternal sera from 57 cases of SSD and 95 matched controls. There was a greater than twofold increased risk of SSD among subjects exposed to maternal serum DHA in the highest tertile (OR=2.38, 95% CI=1.19, 4.76, p=0.01); no such relationship was found between AA and SSD. These findings suggest that elevated maternal DHA is associated with increased risk for the development of SSD in offspring.

Maternal arachidonic acid supplementation improves neurodevelopment in young adult offspring from rat dams with and without diabetes

Maternal diabetes may compromise infant arachidonic acid (AA) status and development. This study tested if maternal AA supplementation improves neurodevelopment in adult offspring. Rat dams were randomized into 6 groups: Saline-Placebo, streptozotocin-induced diabetes with glucose controlled at <13mmol/L, or poorly controlled at 13-20mmol/L using insulin; and fed either a Control or AA (0.5% fat) diet throughout reproduction. Weaned-offspring were fed regular chow to 12 weeks of age. Testing included exploratory behavior, rota rod and water maze (WM). Poorly controlled offspring showed longer (p≤0.018) escape-latency on testing-day 1 WM but not thereafter (p>0.05). Maternal glucose concentration positively correlated with (p=0.006) male offspring testing-day 1 WM latency. The AA-diet offspring performed better in WM and rota rod (p≤0.032) and showed higher exploratory behavior (p=0.008) than Control-diet offspring. These data suggest maternal hyperglycemia has longstanding consequences to initial stages of learning in the offspring. Maternal AA supplementation and training positively influence learning outcomes.

Animal models in diabetes and pregnancy

The worldwide increase in the incidence of diabetes, the increase in type 2 diabetes in women at reproductive ages, and the cross-generation of the intrauterine programming of type 2 diabetes are the bases for the growing interest in the use of experimental diabetic models in order to gain insight into the mechanisms of induction of developmental alterations in maternal diabetes. In this scenario, experimental models that present the most common features of diabetes in pregnancy are highly required. Several important aspects of human diabetic pregnancies such as the increased rates of spontaneous abortions, malformations, fetoplacental impairments, and offspring diseases in later life can be approached by using the appropriate animal models. The purpose of this review is to give a practical and critical guide into the most frequently used experimental models in diabetes and pregnancy, discuss their advantages and limitations, and describe the aspects of diabetes and pregnancy for which these models are thought to be adequate. This review provides a comprehensive view and an extensive analysis of the different models and phenotypes addressed in diabetic animals throughout pregnancy. The review includes an analysis of the surgical, chemical-induced, and genetic experimental models of diabetes and an evaluation of their use to analyze early pregnancy defects, induction of congenital malformations, placental and fetal alterations, and the intrauterine programming of metabolic diseases in the offspring's later life.

Long-term effects of gestational diabetes on offspring health are more pronounced in skeletal growth than body composition and glucose tolerance

Infants of diabetic mothers may have low arachidonic acid (AA) and develop obesity and insulin resistance in adulthood. The present study tested the effect of maternal diabetes and AA supplementation on offspring body composition, bone mass and glucose tolerance from 4 to 12 weeks. Rat dams were randomised into six groups using a 3 × 2 design. The rat dams were treated using the following treatments: saline-placebo, streptozotocin-induced diabetes (STZ) with glucose controlled at < 13 mmol/l (STZ/GC) or poorly controlled at 13-20 mmol/l (STZ/PC) using insulin, and fed either a control or an AA (0.5 % of fat) diet throughout reproduction. Weaned offspring were fed regular chow. Measurements included offspring body composition, bone and oral glucose tolerance testing (OGTT) plus liver fatty acids of dam and offspring. Comparable to saline-placebo offspring, the STZ/GC offspring had greater (P < 0.03) whole body and regional bone area than STZ/PC offspring. Maternal glucose negatively correlated (P < 0.05) with offspring whole body bone area and mineral content at 4 weeks in all offspring, and with tibia area in males at 12 weeks. Maternal liver DHA negatively (P < 0.03) correlated with femur and tibia mineral content and tibia mineral density of female offspring at 12 weeks. Offspring from AA-supplemented dams had higher (P = 0.004) liver AA at 4 weeks. Liver AA at 4 weeks positively (P = 0.05) correlated with lumbar spine mineral density in males. OGTT was not affected by maternal treatment or diet. These results suggest that maternal glucose control has long-term consequences to bone health of adult offspring. Skeletal growth appears more sensitive to maternal hyperglycaemia than glucose tolerance.